Title of Invention	SYSTEM, METHOD AND APPARATUS FOR PRODUCING FIRE RATED DOORS
Abstract	The present invention provides a system, method and apparatus for producing fire rated doors having added strength, better finishing and low cost manufacturing flexibility. The fire rated doors are made from two panels 'sandwiched1 together. An optional interior layer (e.g., fire resistant material, lead sheeting, steel or Kevlar) can be added between the door panels for various purposes. Splines, stiles or sticks are inserted in longitudinal channels in the door panels to provide assistance in aligning the door panels and greater hardware holding strength. An intumescent banding material concealed by a banding material around the perimeter of the door seals the door within its frame during a fire. The door design and the automated manufacturing process provide greater design choice, reduced cost and faster fabrication.

Title of Invention

SYSTEM, METHOD AND APPARATUS FOR PRODUCING FIRE RATED DOORS

Abstract

The present invention provides a system, method and apparatus for producing fire rated doors having added strength, better finishing and low cost manufacturing flexibility. The fire rated doors are made from two panels 'sandwiched1 together. An optional interior layer (e.g., fire resistant material, lead sheeting, steel or Kevlar) can be added between the door panels for various purposes. Splines, stiles or sticks are inserted in longitudinal channels in the door panels to provide assistance in aligning the door panels and greater hardware holding strength. An intumescent banding material concealed by a banding material around the perimeter of the door seals the door within its frame during a fire. The door design and the automated manufacturing process provide greater design choice, reduced cost and faster fabrication.

Full Text	Field of Invention The present invention relates in general to the field of door manufacturing and, more particularly, to a system, method and apparatus for producing fire rated doors. Background Art Many methods and techniques for manufacturing doors have been developed over time. For example, FIGURE 1 shows a typical residential door 100 that is constructed from a set of interlocking perimeter boards 102, 104 and 106, internal boards 108, and panels 110 and 112. In another example, FIGURE 2 shows a fire rated door 200 that is constructed from a mineral core 202 sandwiched between two medium density fiberboards 204 and 206. A perimeter channel 208 extends around the sides of the door assembly. An intumescent banding 210 is sandwiched between a first hardwood insert 212 and a second hardwood insert 214, all of which are disposed in the perimeter channel 208. Many other designs exist These prior art designs do not lend themselves well to fully automated manufacturing processes. Moreover, the prior art fire rated doors are expensive and require the internal mineral core. The internal core can be exposed in routed details and may reduce the strength of the door as a result of the reduced thickness of the door panels. In addition, alignment of the panels during assembly can be troublesome and require additional finishing to square the door after assembly. As a result, there is a need for a fire rated door that does not suffer from these deficiencies. Summary of the Invention The present invention provides a system, method and apparatus for producing fire rated doors having added strength, better finishing and low cost manufacturing flexibility. The fire rated doors are made from two panels "sandwiched" together, which minimizes low density core exposure in routed details, improves routing detail appearance, provides a smoother appearance when painted, and increases the overall strength of the door assembly, through improved modulus of elasticity and modulus of rupture. An optional interior layer (e.g., fire resistant material, lead sheeting, steel or Kevlar) can be added between the door panels for various purposes. Splines, stiles or sticks are inserted in longitudinal channels in the door panels to provide assistance in aligning the door panels and greater hardware holding strength. An intumescent banding material concealed by a banding material around the perimeter of the door seals the door within its frame during a fire. The door design and the automated manufacturing process provide greater design choice, reduced cost and faster fabrication. The present invention provides a fire rated door that includes a first routable door panel attached to a second routable door panel. Each door panel has two opposing longitudinal interior channels with each interior channel containing a spline. The attached door panels have a perimeter channel containing an intumescent banding material and an exterior banding to conceal the intumescent banding material. Hie present invention also provides a fire rated door having one or more protective layers disposed between a first routable door panel and a second routable door panel. Each door panel has two opposing longitudinal interior channels. The attached door panels have a perimeter channel. A spline is disposed within each interior channel. An intumescent banding material and an exterior banding to conceal the intumescent banding material are disposed within the perimeter channel. A data device containing production data is embedded within the door. In addition, the present invention provides a fire rated door that includes a first routable door panel attached to a second routable door panel using a fire resistant adhesive and wherein each door panel has two opposing longitudinal interior channels with each interior channel containing a spline. Alternatively, the each door panel may also have a fire resistant coating. Moreover, the present invention provides a method for manufacturing a fire rated door by cutting two longitudinal interior channels into a back side of a door panel, assembling a door slab by inserting a spline in each longitudinal interior channel of a first door panel, attaching a second door panel to the splines and first door panel using an adhesive and applying pressure to door slab to bond the splines and door panels together ,cutting a perimeter channel in the sides of the door slab, inserting an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel, routing a specified design into each panel of the door slab, applying one or more primer coats to the door slab, and machining the door slab to receive a set of hinges and lockset hardware. Note that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps. Furthermore, the present invention provides a manufacturing line to produce fire rated doors having a first set of machines to cut two longitudinal interior channels into a back side of a door panel, a second set of machines to assemble a door slab by inserting a spline in each longitudinal interior channel of a first door panel, attaching a second door panel to the splines and first door panel using an adhesive and applying pressure to door slab to bond the splines and door panels together, a third set of machines to cut a perimeter channel in the sides of the door slab, and insert an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel, a fourth set of machines to route a specified design into each panel of the door slab, a fifth set of machines to apply one or more primer coats to the door slab, a sixth set of machines to machine the door slab to receive a set of hinges and lockset hardware, and one or more conveyors interconnecting the machines to move the door slabs. The present invention is described in detail below with reference to the accompanying drawings. Brief Description of the Drawings Further benefits and advantages of the present invention will become more apparent from the following description of various embodiments that are given by way of example with reference to the accompanying drawings: FIGURE! is a partial perspective exploded view of a door in accordance with the prior art; FIGURE 2 is a partial perspective view with a cut away of a fire rated door in accordance with the prior art; FIGURE 3 is a partial perspective exploded view of a door in accordance with one embodiment of the present invention; FIGURE 4 is a partial perspective exploded view of a door in accordance with another embodiment of the present invention; FIGURE 5 is a flow chart illustrating a method to manufacture a door in accordance with one embodiment the present invention; FIGURE 6 is a flow chart illustrating a method to manufacture a door in accordance with another embodiment the present invention; FIGURE 7 is a flow chart illustrating a method to manufacture a door in accordance with yet another embodiment of the present invention; FIGURE 8 is a partial perspective exploded view of a fire rated door in accordance with one embodiment of the present invention; FIGURE 9 is a partial perspective exploded view of a fire rated door in accordance with another embodiment of the present invention; FIGURE 10 is a flow chart illustrating a method to manufacture a fire rated door in accordance with one embodiment the present invention; FIGURE 11 is a flow chart illustrating a method to manufacture a fire rated door in accordance with another embodiment the present invention; FIGURE 12 is a flow chart illustrating a method to manufacture a fire rated door in accordance with yet another embodiment the present invention; and FIGURE 13 is a block diagram of a manufacturing line in accordance with one embodiment of the present invention. Description of the Invention While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention. To facilitate the understanding of this invention, a number of terms are defined below. Terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as "a", "an" and "the" are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as outlined in the claims. The present invention provides a system, method and apparatus for producing fire rated doors having added strength, better finishing and low cost manufacturing flexibility. The fire rated doors are made from two panels "sandwiched" together, which minimizes low density core exposure in routed details, improves routing detail appearance, provides a smoother appearance when painted, and increases the overall strength of the door assembly, through improved modulus of elasticity and modulus of rupture. An optional interior layer (e.g., fire resistant material, lead sheeting, steel or Kevlar) can be added between the door panels for various purposes. Splines, stiles or sticks are inserted in longitudinal channels in the door panels to provide assistance in aligning the door panels and greater hardware holding strength. An intumescent banding material concealed by a banding material around the perimeter of the door seals the door within its frame during a fire. The door design and the automated manufacturing process provide greater design choice, reduced cost and fester fabrication. Now referring to FIGURE 3, a partial perspective exploded view of a door 300 in accordance with one embodiment of the present invention is shown. The door 300 includes a first routable door panel 302 attached to a second routable door panel 304. The door panels 302 and 304 can be made of a lignocellulosic substrate, a wood, a wood composite, , a medium density fiberboard or a combination thereof.. Each door panel 302 and 304 has two opposing longitudinal interior channels, slots, grooves or recesses 306. Each interior channel, slot or groove 306 contains a spline, stick or rail 308. The spline, stick or rail 308 can be made of a hardwood or other hard composite material. The splines 308 are used to locate and align the door panels so that the door can be assembled using automated machines. As a result, the use of the splines 308 reduces errors and waste, improves the quality of the door and speeds up the production process. Alternatively, the splines can be inserted and glued on edge of the door panels in stick or tape format into a machined recess. The door panels 302 and 304 and splines 308 are attached together using an adhesive. The type of adhesive used will depend on the material properties of the door panel 102 and where the door 300 is to be installed. The adhesive may be an epoxy or glue, and may be applied by various means such as brushing or spraying, for example. A double sided tape may also be employed for some applications. The adhesive 106 may be . applied to a portion or portions of one or both of the door panels 302 and 304. The adhesive is, however, preferably spread over Ihe extent of one of the door panels 302 or 304 and is a water soluble latex based glue, isocyanate resin/glue, catalyzed glue (e.g., epoxies and contact cements) or urethane-based resin. The amount of adhesive applied to adhere the door panels 302 and 304 together is an amount at least sufficient to hold these two members together such that the door 300 can be handled and installed into its final application. The use of two panels "sandwiched" together minimizes low density core exposure in routed details, improves routing detail appearance, provides a smoother appearance when painted, and increases the overall strength of the door assembly, through improved modulus of elasticity and modulus of rupture. The outward facing portions of the door panels 302 and 304 can be finished to suit the environment in which the door 300 is being installed. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. Referring now to FIGURE 4, a partial perspective exploded view of a door in accordance with another embodiment of the present invention is shown. The door 400 includes a first routable door panel 402 attached to a second routable door panel 404. The door panels 402 and 404 can be made of a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof. Each door panel 402 and 404 has two opposing longitudinal interior channels, slots, grooves or recesses 406 and a large interior channel, slot or recess 408 between the two opposing longitudinal interior channels 406. Bach interior channel 306 contains a spline, stick or rail 410. The spline, stick or rail 410 can be made of a hardwood or other hard composite material, and provides the benefits previously described. The large interior channel contains one or more protective layers 412. The protective layers 412 can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. For example, the protective layers can be one or more gypsum boards, one or more metallic sheets, one or more lead sheets, one or more Kevlar sheets, one or more ceramic sheets, a layer of urethane foam, a layer of graphite, a wire mesh or a combination thereof. The door panels 402 and 404, splines 410 and protective layers 412 are attached together using an adhesive as previously described. The outward facing portions of the door panels 402 and 404 can be finished to suit the environment in which the door 400 is being installed. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. • Now referring to FIGURE 5, a flow chart illustrating a method 500 to manufacture a door in accordance with one embodiment the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 502. Then in ■ block 504, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) attaching a second door panel to the splines and the first door panel using an adhesive and (c) applying pressure to the door slab to bond the splines and the door panels together. A specified design is routed into each door panel of the door slab in block 506. One or more primer coats are applied to the door slab in block 508. The primer coats can be applied using an electrostatic powder coating process. The door slab is machined to receive a set of hinges and lockset hardware in block 510. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. Note also that this method can-be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps. Referring now to FIGURE 6, a flow chart illustrating a method 600 to manufacture a door in accordance with another embodiment the present invention is shown. Two longitudinal interior channels and a large interior channel between the two longitudinal interior channels are cut into a back side of a door panel in block 602. Then in block 604, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) inserting one or more protective layers in the large interior channel between the splines, (c) attaching a second door panel to the splines, the protective layers and the first door panel using an adhesive, and (d) applying pressure to the door slab to bond the splines and the door panels together. The protective layers can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof A specified design is routed into each door panel of the door slab in block 606. One or more primer coats are applied to the door slab in block 608. The primer coats can be applied using an electrostatic powder coating process. The door slab is machined to receive a set of hinges and lockset hardware in block 610. Alternatively, the one or more protective layers are inserted between the door panels without using the large interior channel. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. Note also that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps. Now referring to FIGURE 7, a flow chart illustrating a method 700 to manufacture a door in accordance with yet another embodiment of the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 702. Then in block 704, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) inserting a data device into the door slab, (c) attaching a second door panel to the splines and the first door panel using an adhesive, and (d) applying pressure to the door slab to bond the splines and the door panels together. A specified design is routed into each door panel of the door slab in block 706. One or more primer coats are applied to the door slab in block 708. The primer coats can be applied using an electrostatic powder coating process. The door slab is machined to receive a set of hinges and lockset hardware in block 710. A chemical is injected into one or more screw pilot holes to increase the screw holding capacity or pull strength in block 712. The door slab is then packaged for shipping in block 714. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. Note also that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps. Referring now to FIGURE 8, a partial perspective exploded view of a fire rated door 800 in accordance with one embodiment of the present invention is shown. The fire rated door 800 includes one or more protective layers 802 disposed between a first routable door panel 804 and a second routable door panel 806. The door panels 804 and 806 can be made of a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof. The protective layers 802 can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. Each door panel 804 and 806 has two opposing longitudinal interior channels 808. The attached door panels 800 have a perimeter channel 810. Each interior channel 808 contains a spline, stick or rail 812. The spline 812 can be made of a hardwood or other hard composite material, and provides the benefits previously described. An intumescent banding material 814 and an exterior banding 816 to conceal the intumescent banding material 814 are disposed within the perimeter channel 810. As shown, the perimeter channel 810 extends to the spline 812. Alternatively, the perimeter Channel 810 does not extend to the spline 812. A data device (not shown), such as a radio frequency identification device (RFID), containing production data is embedded within the door. The production data may include a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program (CNC) or a combination thereof. The protective layers 802, door panels 804 and 806 and splines 812 are attached together using an adhesive. Note also that an adhesive having fire retardant properties can be used. Likewise, the door panels can be coated with a fire resistant or retardant material. Now referring to FIGURE 9, a partial perspective exploded view of a fire rated door in accordance with another embodiment of the present invention is shown. The fire rated door 900 includes one or more protective layers 902 disposed between a first routable door panel 904 and a second routable door panel 906. The door panels 904 and 906 can be made of a lignocelluiosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof. The protective layers 902 can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. Each door panel 904 and 906 has two opposing longitudinal interior channels 908. The attached door panels 900 have a perimeter channel 810. Each interior channel 908 contains a spline, stick or rail 912. The spline 912 can be made of a hardwood or other hard composite material, and provides the benefits previously described. An intumescent banding material 914 and an exterior banding 916 to conceal the intumescent banding material 914 are disposed within the perimeter channel 910. As shown, the perimeter channel 910 extends to the spline 912. Alternatively, the perimeter channel 910 does not extend to the spline 912. A data device (not shown), such as a radio frequency identification device (RFID), containing production data is embedded within the door. The production data may include a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program (CNC) or a combination thereof. The protective layers 902, door panels 904 and 906 and splines 912 are attached together using an adhesive. The one or more protective layers 902 and splines, 912 are coated with an intumescent material 818. Note that the door panels 904 and 906 can also be coated with the intumescent material 818 or other fire retardant or resistant material. Note also that an adhesive having fire retardant properties can be used. Referring now to FIGURE 10, a flow chart illustrating a method 1000 to manufacture a fire rated door in accordance with one embodiment the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 1002. Then in block 1004, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) attaching a second door panel to the splines and the first door panel using an adhesive and (c) applying pressure to the door slab to bond the splines and the door panels together. A perimeter channel is cut in the sides of the door slab in block 1006. Note that the perimeter channel can extend to the spline. An intumescent banding material and an exterior banding to conceal the intumescent banding material are inserted into the perimeter channel in block 1008. Alternatively, the stiles and door panels can contain intumescent or fire resistant materials. A specified design is routed into each door panel of the door slab in block 1010. One or more primer coats are applied to the door slab in block 1012. The primer coats can be applied using an electrostatic powder coating process. Alternatively, the stiles, door panels and/or primer coats can contain intumescent or fire retardant/resistant materials. Note also that an adhesive having fire retardant properties can be used. The door slab is machined to receive a set of hinges and lockset hardware in block 1014. Note that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps. Now referring to FIGURE 11, a flow chart illustrating a method 1100 to manufacture a fire rated door in accordance with another embodiment the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 1102. Then in block 1104, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) inserting one or more protective layers between the stiles, (c) inserting a data device into the door slab, (d) attaching a second door panel to the splines, the protective layers and the first door panel using an adhesive, and (e) applying pressure to the door slab to" bond the splines and the door panels together. The protective layers can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. The data device contains production data, such as a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program (CNC) or a combination thereof. A perimeter channel is cut in the sides of the door slab in block 1106. Note that the perimeter channel can extend to the spline. An intumescent banding material and an exterior banding to conceal the intumescent banding material are inserted into the perimeter channel in block 1108. One or more primer coats are applied to the door slab in block 1112. The primer coats can be applied using an electrostatic powder coating process. Alternatively, the protective layers, stiles, door panels and/or primer coats can contain intumescent or fire retardant/resistant materials. Note also that an adhesive having fire retardant properties can be used. A specified design is routed into each door panel of the door slab in block 1110. The door slab is machined to receive a set of hinges and lockset hardware in block 1114. Note that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps. Referring now to FIGURE 12, a flow chart illustrating a method 1200 to manufacture a fire rated door in accordance with yet another embodiment the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 1202. One or more protective layers are coated with an intumescent material in block 1204 and the stiles are coated with the intumescent material in block 1206. The protective layers can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding, material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. Then in block 1208, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) inserting one or more protective layers between the stiles, (c) inserting a data device into the door slab, (d) attaching a second door panel to the splines, the protective layers and the first door panel using an adhesive, and (e) applying pressure to the door slab to bond the splines and the door panels together. The data device contains production data, such as a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program (CNC) or a combination thereof. A perimeter channel is cut in the sides of the door slab in block 1210. Note that the perimeter channel can extend to the spline. An intumescent banding material and an exterior banding to conceal the intumescent banding material are inserted into the perimeter channel in block 1212. A specified design is routed into each door panel of the door slab in block 1214. One or more primer coats are applied to the door slab in block 1216. The primer coats can be applied using an electrostatic powder coating process. Alternatively, the protective layers, stiles, door panels and/or primer coats can contain intumescent or fire resistant/retardant materials. Note also that an adhesive having fire retardant properties can be used. The door slab is machined to receive a set of hinges and lockset hardware in block 1215. Note that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps. Now referring to FIGURE 13,- a block diagram of a manufacturing line 1300 in accordance with one embodiment of the present invention is shown. A first set of machines 1302 cuts two longitudinal interior channels into a back side ofadoorpanel, A second set of machines 1304 assembles a door slab by inserting a spline in each longitudinal interior channel of a first door panel, attaching a second door panel to the splines and first door panel using an adhesive and applying pressure to door slab to bond the splines and door panels together. A third set of machines 1306 cut a perimeter channel in the sides of the door slab, and insert an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel. A fourth set of machines 1308 route a specified design into each panel of the door slab. A fifth set of machines 1310 apply one or more primer coats to the door. slab.. A sixth set of machines 1312 machine the door slab to receive a set of hinges and lockset hardware. One or more conveyors 1314 interconnect the machines to move the door slabs. The manufacturing line may also include a seventh set of machines 1316 to cut large sheets of a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof into a door panel. An eighth set of machines 1318 can be used to apply an intumescent coating to the splines and a ninth set of machines 1320 can be used to apply an intumescent coating to the one or more protective layers. The one or more protective layers are inserted between the first door panel and the second panel by the second set of machines 1304. A tenth set of machines 1322 cut the protective layers, such as gypsum board, to the proper size. An eleventh set of machines 1324 prehang and package the doors. The second set of machines 1304 can also a data device into the door slab. The data device provides one or more instructions to control one or more of the machines. As a result, the specified design for the router can be different for successive door slabs moving through the line. Moreover, the data device allows each door slab to be customized to satisfy a purchase order. AH of the machines can be fully automated or semi-automated. A more specific example of a production process in accordance with the present invention will not be described. The door panels are sawn to rough size from large sheets. The door panels are sized on long edges and grooved for splines or sticks, if necessary. The panels from the previous saw operation are automatically fed into a production line of several machines. The first operation in that line trims the long edges of the panels to a consistent and predetermined size for the product required. This same machine also machines two grooves to accept the aligning splines or sticks. After the panels leave the machine in the step above, they are coated with a PUR hot melt adhesive, and then assembled into a door slab. This may consist of two door panels with encapsulated locating splines or sticks, an assembly without the splines, or a fire door or other type of assembly with or without splines. The third layer in a fire door assembly consists of a layer of 5/8" or 1/2" thick type C or type X gypsum board. This board may be coated with an intumescent or fire resistant paint or it may have the intumescent ingredients mixed within the gypsum. The splines, if present, may also be coated with the same intumescent or fire resistant paint. It is at this point that the RFID device is inserted internally. This RFID device will store information about the door, identifying it to all subsequent operations, so that the proper machine programs and parameters will be utilized during the processes of manufacturing. After the slab is assembled, it will run through pressure devices to assure a quality bond between the components, and will be automatically stacked down onto roller conveyor. The next step in the process is to automatically feed the doors from stacks on the roller conveyor into an automated line that will first machine the short sides of the door so that they are parallel and to a specific dimension. The doors are then rotated 90 degrees and fed into a second machine that machines the long sides, giving them a 3 degree relief angle, makes those sides parallel and to proper dimension. These operations will also sand the machined edges to conceal the joint between the panels, and chamfer or radius the edges. When fire rated doors are being produced, the machines will also machine clearance for and install intumescent banding along all four edges, and will also have the ability to install another layer of paintable banding over the intumescent banding, to provide the required appearance of a solid substrate. After the machining, banding and sanding operations, the doors will again be automatically stacked on roller conveyor. Doors are fed through automated router lines, where the first router machines one side of the door, a second station inverts the door, and another router machines the opposite side before they are automatically stacked. After the doors have been sized and/or banded, they will be automatically fed from stacks into machine lines that will perform the routing per customer order to give them the desired final appearance of being of raised panel construction and/or carved. The first machine will work on one panel of the door, and when that operation is complete, the doors will be conveyed to a device that inverts itso that it can be introduced to a second machine which will work on the opposite panel. When this operation is complete, the doors will again be automatically stacked on roller conveyor. The doors are fed through an automated prime coating line, where the top side is finished first, the doors are inverted, and the opposite side is finished. The doors then are fed into a second identical line which applies a second coat to all panels of the doors before they are automatically stacked. The doors are fed one at a time through a process that first-sands the top panel to remove imperfections, denibs (remove whiskers) and cleans, preheats, sprays primer, cures the primer and denibs again. The doors are then inverted and the same steps are performed on the opposite panel, with one additional step: at the end of the process line, the long edges are denibbed. At this point, the doors are automatically sent into a second line which is identical to the first, applying a second coat to all panels. The doors are then automatically stacked on roller conveyor. Alternatively, the doors are fed through an automated powder coat finish line. The doors are loaded either by hand or by a robot onto racks mounted to an overhead conveyor system. This conveyor system can be of a line conveyor type or a "power and free" type system. The doors are electrically charged either through contact through the racks/hooks and the conveyor system itself, or a conductive primer coating has been applied. After the doors are loaded onto the racks, they are sent through the preheat process. The preheat mechanism can be via one of three types; IR electric, IR gas catalytic or thermally via . heated air circulation. Care needs to be taken in this process not to heat the doors too quickly, which can cause moisture to be driven to the panel resulting in cracks in the panel of the doors. Another issue could be scorching of the door panel. After preheating, the doors go to the powder application booth. The powder can be applied manually, semi-automatically (where an operator must be present to touch up areas to ensure complete coverage) or automatically. The powder itself can be of three types; theimo cure, low heat thermo cure or UV cure. After the powder is applied, the doors then proceed to the curing process. The curing process is accomplished through the application of heat via IR devices. These IR devices can be of different wavelength for different applications, or they can be of a combination of short, medium and long wavelength to improve the curing properties. At the end of the curing cyple, a UV light source can be utilized for the UV cured powder type. Next in the process is the cool, down tunnel where cool air is circulated to bring the doors down to a temperature where they can' be handled. They are then removed from the conveyor system and stacked, either manually or with a robot. The panels that can be obtained with the above process can range in texture from smooth to rough* and the gloss level can range from low to high gloss. The doors are fed through an automated machine line where they are prepared for hinges and lock sets as required. After this operation, the doors pass through an automatic inspection station, where they are checked via machine vision and laser inspection/measuring equipment for conformation to standards, and to verify that the doors match the intended specifications recorded on the enclosed RFID chip. They are then automatically stacked and packaged for shipment This machine line will machine the edges of the doors for the proper hinges and lockset hardware. The doors are automatically fed into and stacked from this process as well. It is after this operation where we may inject the pilot holes for the hinge screws with the chemical to improve the screw holding properties. Each of these machine lines will receive the instructions for what work is to be performed on each door via the encoded information stored on the embedded RFID device. Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification, but only by the claims. WE CLAIM: Claim 1: A fire rated door comprising: a first routable door-sized panel attached back-to-back to a second routable door-sized panel such that two longitudinal interior channels are formed by opposing longitudinal interior channels in the back of each door-sized panel with each formed longitudinal interior channel containing a spline; a perimeter channel in the sides of the door containing an intumescent banding material; an exterior banding to conceal the intumescent banding material; and the first routable door-sized panel and the second routable door-sized panel comprise a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof. Claim 2: The door as recited in claim 1, further comprising: one or more protective layers disposed between the first routable door-sized panel and the second routable door-sized panel; and wherein the one or more protective layers comprise a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. Claim 3: The door as recited in claim 2, wherein the one or more protective layers comprise one or more gypsum boards, one or more metallic sheets, one or more lead sheets, one or more Kevlar sheets, one or more ceramic sheets, a layer of urethane foam, a layer of graphite, a wire mesh or a combination thereof. Claim 4: The door as recited in claim 2, wherein the one or more protective layers contain an intumescent or fire resistant material, or are coated with the intumescent or fire resistant material. Claim 5: The door as recited in claim 1, wherein the perimeter channel along the longitudinal sides of the door extend to the spline. Claim 6: The door as recited in claim 1, further comprising a data device containing production data embedded within the door, wherein the production data comprises a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program or a combination thereof. Claim 7: The door as recited in claim 1, wherein the splines contain an intumescent or fire resistant material, or are coated with an intumescent or fire resistant material. Claim 8: The door as recited in claim 1, wherein the first routable door-sized panel and the second routable door-sized panel contain an intumescent or fire resistant material, or are coated with the intumescent or fire resistant material. Claim 9: A method for manufacturing a fire rated door comprising the steps of: cutting two longitudinal interior channels into a back side of a first door-sized panel and a second door-sized panel, wherein the door-sized panel comprising a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof; assembling a door slab by inserting a spline in each longitudinal interior channel of the first door-sized panel, attaching the back side of the second door-sized panel to the splines and the back side of the first door-sized panel using an adhesive and applying pressure to the door slab to bond the splines and the door-sized panels together; cutting a perimeter channel in the sides of the door slab; inserting an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel; routing a specified design into a front side of each door-sized panel of the door slab; applying one or more primer coats to the door slab; and machining the door slab to receive a set of hinges and lockset hardware. Claim 10: The method as recited in claim 9, further comprising the step of applying an intumescent coating to the splines. Claim 11: The method as recited in claim 9, further comprising the step of: inserting a data device into the door slab; and injecting a chemical into one or more screw pilot holes to increase screw holding capacity or pull strength. Claim 12: The method as recited in claim 9, further comprising the step of inserting one or more protective layers between the first door-sized panel and the second door-sized panel. Claim 13: The method as recited in claim 12, further comprising the step of applying an intumescent coating to the one or more protective layers. Claim 14: The method as recited in claim 9, wherein the one or more primer coats include an intumescent material. Claim 15: The method as recited in claim 9, wherein the one or more primer coats are applied with an electrostatic powder coating process. Claim 16: A manufacturing line to produce fire rated doors comprising: a first set of machines to cut two longitudinal interior channels into a back side of a first door-sized panel and a second door-sized panel; a second set of machines to assemble a door slab by inserting a spline in each longitudinal interior channel of the first door-sized panel, attaching the back side of the second door-sized panel to the splines and the back side of first door-sized panel using an adhesive and applying pressure to door slab to bond the splines and the door-sized panels together; a third set of machines to cut a perimeter channel in the sides of the door slab, and insert an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel; a fourth set of machines to route a specified design into a front side of each door-sized panel of the door slab; a fifth set of machines to apply one or more primer coats to the door slab; a sixth set of machines to machine the door slab to receive a set of hinges and lockset hardware; and one or more conveyors interconnecting the machines to move the door slabs. Claim 17: The manufacturing line as recited in claim 16, further comprising a seventh set of machines to cut large sheets of a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof into a door panel. Claim 18: The manufacturing line as recited in claim 16, wherein: the first set of machines further trims the long edges of the door-sized panels; the perimeter channel along the longitudinal sides of the door slab extend to the spline; and the one or more primer coats include an intumescent material. Claim 19: The manufacturing line as recited in claim 16, wherein the specified design is different for successive door slabs moving through the line. Claim 20: The manufacturing line as recited in claim 16, wherein each door slab is customized to satisfy a purchase order. Claim 21: The manufacturing line as recited in claim 16, further comprising an eighth set of machines to apply an intumescent coating to the splines. Claim 22: The manufacturing line as recited in claim 16, wherein: the second set of machines further inserts a data device that provides one or more instructions to control one or more of the machines into the door slab; and all of the machines are automated or semi-automated. Claim 23: The manufacturing line as recited in claim 16, wherein the second set of machines further inserts one or more protective layers between the first door-sized panel and the second door-sized panel. Claim 24: The manufacturing line as recited in claim 23, further comprising a ninth set of machines to apply an intumescent coating to the one or more protective layers. Claim 25: The manufacturing line as recited in claim 16, wherein: the one or more primer coats are applied with an electrostatic powder coating process; and the sixth set of machines further injects a chemical into one or more screw pilot holes to increase screw holding capacity or pull strength.

Full Text

Field of Invention
The present invention relates in general to the field of door manufacturing and, more particularly, to a system, method and apparatus for producing fire rated doors.
Background Art
Many methods and techniques for manufacturing doors have been developed over time. For example, FIGURE 1 shows a typical residential door 100 that is constructed from a set of interlocking perimeter boards 102, 104 and 106, internal boards 108, and panels 110 and 112. In another example, FIGURE 2 shows a fire rated door 200 that is constructed from a mineral core 202 sandwiched between two medium density fiberboards 204 and 206. A perimeter channel 208 extends around the sides of the door assembly. An intumescent banding 210 is sandwiched between a first hardwood insert 212 and a second hardwood insert 214, all of which are disposed in the perimeter channel 208. Many other designs exist
These prior art designs do not lend themselves well to fully automated manufacturing processes. Moreover, the prior art fire rated doors are expensive and require the internal mineral core. The internal core can be exposed in routed details and may reduce the strength of the door as a result of the reduced thickness of the door panels. In addition, alignment of the panels during assembly can be troublesome and require additional finishing to square the door after assembly. As a result, there is a need for a fire rated door that does not suffer from these deficiencies.
Summary of the Invention
The present invention provides a system, method and apparatus for producing fire rated doors having added strength, better finishing and low cost manufacturing flexibility. The fire rated doors are made from two panels "sandwiched" together, which minimizes low density core exposure in routed details, improves routing detail appearance, provides a smoother appearance when painted, and increases the overall strength of the door assembly, through improved modulus of elasticity and modulus of rupture. An optional interior layer (e.g., fire resistant material, lead sheeting, steel or Kevlar) can be added between the door panels for various purposes. Splines, stiles or sticks are inserted in
longitudinal channels in the door panels to provide assistance in aligning the door panels and greater hardware holding strength. An intumescent banding material concealed by a banding material around the perimeter of the door seals the door within its frame during a fire. The door design and the automated manufacturing process provide greater design choice, reduced cost and faster fabrication.
The present invention provides a fire rated door that includes a first routable door panel attached to a second routable door panel. Each door panel has two opposing longitudinal interior channels with each interior channel containing a spline. The attached door panels have a perimeter channel containing an intumescent banding material and an exterior banding to conceal the intumescent banding material.
Hie present invention also provides a fire rated door having one or more protective layers disposed between a first routable door panel and a second routable door panel. Each door panel has two opposing longitudinal interior channels. The attached door panels have a perimeter channel. A spline is disposed within each interior channel. An intumescent banding material and an exterior banding to conceal the intumescent banding material are disposed within the perimeter channel. A data device containing production data is embedded within the door.
In addition, the present invention provides a fire rated door that includes a first routable door panel attached to a second routable door panel using a fire resistant adhesive and wherein each door panel has two opposing longitudinal interior channels with each interior channel containing a spline. Alternatively, the each door panel may also have a fire resistant coating.
Moreover, the present invention provides a method for manufacturing a fire rated door by cutting two longitudinal interior channels into a back side of a door panel, assembling a door slab by inserting a spline in each longitudinal interior channel of a first door panel, attaching a second door panel to the splines and first door panel using an adhesive and applying pressure to door slab to bond the splines and door panels together ,cutting a perimeter channel in the sides of the door slab, inserting an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel, routing a specified design into each panel of the door slab, applying one or more primer coats to the door slab, and machining the door slab to receive a set of hinges and lockset hardware. Note that this method can be implemented using a computer
program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps.
Furthermore, the present invention provides a manufacturing line to produce fire rated doors having a first set of machines to cut two longitudinal interior channels into a back side of a door panel, a second set of machines to assemble a door slab by inserting a spline in each longitudinal interior channel of a first door panel, attaching a second door panel to the splines and first door panel using an adhesive and applying pressure to door slab to bond the splines and door panels together, a third set of machines to cut a perimeter channel in the sides of the door slab, and insert an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel, a fourth set of machines to route a specified design into each panel of the door slab, a fifth set of machines to apply one or more primer coats to the door slab, a sixth set of machines to machine the door slab to receive a set of hinges and lockset hardware, and one or more conveyors interconnecting the machines to move the door slabs.
The present invention is described in detail below with reference to the accompanying drawings.
Brief Description of the Drawings
Further benefits and advantages of the present invention will become more apparent from the following description of various embodiments that are given by way of example with reference to the accompanying drawings:
FIGURE! is a partial perspective exploded view of a door in accordance with the prior art;
FIGURE 2 is a partial perspective view with a cut away of a fire rated door in accordance with the prior art;
FIGURE 3 is a partial perspective exploded view of a door in accordance with one embodiment of the present invention;
FIGURE 4 is a partial perspective exploded view of a door in accordance with another embodiment of the present invention;
FIGURE 5 is a flow chart illustrating a method to manufacture a door in accordance with one embodiment the present invention;
FIGURE 6 is a flow chart illustrating a method to manufacture a door in accordance with another embodiment the present invention;
FIGURE 7 is a flow chart illustrating a method to manufacture a door in accordance with yet another embodiment of the present invention;
FIGURE 8 is a partial perspective exploded view of a fire rated door in accordance with one embodiment of the present invention;
FIGURE 9 is a partial perspective exploded view of a fire rated door in accordance with another embodiment of the present invention;
FIGURE 10 is a flow chart illustrating a method to manufacture a fire rated door in accordance with one embodiment the present invention;
FIGURE 11 is a flow chart illustrating a method to manufacture a fire rated door in accordance with another embodiment the present invention;
FIGURE 12 is a flow chart illustrating a method to manufacture a fire rated door in accordance with yet another embodiment the present invention; and
FIGURE 13 is a block diagram of a manufacturing line in accordance with one embodiment of the present invention.
Description of the Invention
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.
To facilitate the understanding of this invention, a number of terms are defined below. Terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as "a", "an" and "the" are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as outlined in the claims.
The present invention provides a system, method and apparatus for producing fire rated doors having added strength, better finishing and low cost manufacturing flexibility. The fire rated doors are made from two panels "sandwiched" together, which minimizes low density core exposure in routed details, improves routing detail appearance, provides a smoother appearance when painted, and increases the overall strength of the door assembly, through improved modulus of elasticity and modulus of rupture. An optional
interior layer (e.g., fire resistant material, lead sheeting, steel or Kevlar) can be added between the door panels for various purposes. Splines, stiles or sticks are inserted in longitudinal channels in the door panels to provide assistance in aligning the door panels and greater hardware holding strength. An intumescent banding material concealed by a banding material around the perimeter of the door seals the door within its frame during a fire. The door design and the automated manufacturing process provide greater design choice, reduced cost and fester fabrication.
Now referring to FIGURE 3, a partial perspective exploded view of a door 300 in accordance with one embodiment of the present invention is shown. The door 300 includes a first routable door panel 302 attached to a second routable door panel 304. The door panels 302 and 304 can be made of a lignocellulosic substrate, a wood, a wood composite, , a medium density fiberboard or a combination thereof.. Each door panel 302 and 304 has two opposing longitudinal interior channels, slots, grooves or recesses 306. Each interior channel, slot or groove 306 contains a spline, stick or rail 308. The spline, stick or rail 308 can be made of a hardwood or other hard composite material. The splines 308 are used to locate and align the door panels so that the door can be assembled using automated machines. As a result, the use of the splines 308 reduces errors and waste, improves the quality of the door and speeds up the production process. Alternatively, the splines can be inserted and glued on edge of the door panels in stick or tape format into a machined recess. The door panels 302 and 304 and splines 308 are attached together using an adhesive. The type of adhesive used will depend on the material properties of the door panel 102 and where the door 300 is to be installed. The adhesive may be an epoxy or glue, and may be applied by various means such as brushing or spraying, for example. A double sided tape may also be employed for some applications. The adhesive 106 may be . applied to a portion or portions of one or both of the door panels 302 and 304. The adhesive is, however, preferably spread over Ihe extent of one of the door panels 302 or 304 and is a water soluble latex based glue, isocyanate resin/glue, catalyzed glue (e.g., epoxies and contact cements) or urethane-based resin. The amount of adhesive applied to adhere the door panels 302 and 304 together is an amount at least sufficient to hold these two members together such that the door 300 can be handled and installed into its final application. The use of two panels "sandwiched" together minimizes low density core exposure in routed details, improves routing detail appearance, provides a smoother appearance when painted, and increases the overall strength of the door assembly, through
improved modulus of elasticity and modulus of rupture. The outward facing portions of the door panels 302 and 304 can be finished to suit the environment in which the door 300 is being installed. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material.
Referring now to FIGURE 4, a partial perspective exploded view of a door in accordance with another embodiment of the present invention is shown. The door 400 includes a first routable door panel 402 attached to a second routable door panel 404. The door panels 402 and 404 can be made of a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof. Each door panel 402 and 404 has two opposing longitudinal interior channels, slots, grooves or recesses 406 and a large interior channel, slot or recess 408 between the two opposing longitudinal interior channels 406. Bach interior channel 306 contains a spline, stick or rail 410. The spline, stick or rail 410 can be made of a hardwood or other hard composite material, and provides the benefits previously described. The large interior channel contains one or more protective layers 412. The protective layers 412 can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. For example, the protective layers can be one or more gypsum boards, one or more metallic sheets, one or more lead sheets, one or more Kevlar sheets, one or more ceramic sheets, a layer of urethane foam, a layer of graphite, a wire mesh or a combination thereof. The door panels 402 and 404, splines 410 and protective layers 412 are attached together using an adhesive as previously described. The outward facing portions of the door panels 402 and 404 can be finished to suit the environment in which the door 400 is being installed. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. •
Now referring to FIGURE 5, a flow chart illustrating a method 500 to manufacture a door in accordance with one embodiment the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 502. Then in ■ block 504, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) attaching a second door panel to the splines and the first door panel using an adhesive and (c) applying pressure to the door slab to bond the splines
and the door panels together. A specified design is routed into each door panel of the door slab in block 506. One or more primer coats are applied to the door slab in block 508. The primer coats can be applied using an electrostatic powder coating process. The door slab is machined to receive a set of hinges and lockset hardware in block 510. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. Note also that this method can-be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps.
Referring now to FIGURE 6, a flow chart illustrating a method 600 to manufacture a door in accordance with another embodiment the present invention is shown. Two longitudinal interior channels and a large interior channel between the two longitudinal interior channels are cut into a back side of a door panel in block 602. Then in block 604, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) inserting one or more protective layers in the large interior channel between the splines, (c) attaching a second door panel to the splines, the protective layers and the first door panel using an adhesive, and (d) applying pressure to the door slab to bond the splines and the door panels together. The protective layers can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof A specified design is routed into each door panel of the door slab in block 606. One or more primer coats are applied to the door slab in block 608. The primer coats can be applied using an electrostatic powder coating process. The door slab is machined to receive a set of hinges and lockset hardware in block 610. Alternatively, the one or more protective layers are inserted between the door panels without using the large interior channel. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. Note also that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps.
Now referring to FIGURE 7, a flow chart illustrating a method 700 to manufacture a door in accordance with yet another embodiment of the present invention is shown. Two
longitudinal interior channels are cut into a back side of a door panel in block 702. Then in block 704, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) inserting a data device into the door slab, (c) attaching a second door panel to the splines and the first door panel using an adhesive, and (d) applying pressure to the door slab to bond the splines and the door panels together. A specified design is routed into each door panel of the door slab in block 706. One or more primer coats are applied to the door slab in block 708. The primer coats can be applied using an electrostatic powder coating process. The door slab is machined to receive a set of hinges and lockset hardware in block 710. A chemical is injected into one or more screw pilot holes to increase the screw holding capacity or pull strength in block 712. The door slab is then packaged for shipping in block 714. Note that the previously described door can be a fire rated door by using an adhesive having fire retardant properties. Likewise, the door panels can be coated with a fire resistant or retardant material. Note also that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps.
Referring now to FIGURE 8, a partial perspective exploded view of a fire rated door 800 in accordance with one embodiment of the present invention is shown. The fire rated door 800 includes one or more protective layers 802 disposed between a first routable door panel 804 and a second routable door panel 806. The door panels 804 and 806 can be made of a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof. The protective layers 802 can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. Each door panel 804 and 806 has two opposing longitudinal interior channels 808. The attached door panels 800 have a perimeter channel 810. Each interior channel 808 contains a spline, stick or rail 812. The spline 812 can be made of a hardwood or other hard composite material, and provides the benefits previously described. An intumescent banding material 814 and an exterior banding 816 to conceal the intumescent banding material 814 are disposed within the perimeter channel 810. As shown, the perimeter channel 810 extends to the spline 812. Alternatively, the perimeter Channel 810 does not extend to the spline 812. A data device (not shown), such as a radio frequency identification device (RFID), containing production
data is embedded within the door. The production data may include a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program (CNC) or a combination thereof. The protective layers 802, door panels 804 and 806 and splines 812 are attached together using an adhesive. Note also that an adhesive having fire retardant properties can be used. Likewise, the door panels can be coated with a fire resistant or retardant material.
Now referring to FIGURE 9, a partial perspective exploded view of a fire rated door in accordance with another embodiment of the present invention is shown. The fire rated door 900 includes one or more protective layers 902 disposed between a first routable door panel 904 and a second routable door panel 906. The door panels 904 and 906 can be made of a lignocelluiosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof. The protective layers 902 can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. Each door panel 904 and 906 has two opposing longitudinal interior channels 908. The attached door panels 900 have a perimeter channel 810. Each interior channel 908 contains a spline, stick or rail 912. The spline 912 can be made of a hardwood or other hard composite material, and provides the benefits previously described. An intumescent banding material 914 and an exterior banding 916 to conceal the intumescent banding material 914 are disposed within the perimeter channel 910. As shown, the perimeter channel 910 extends to the spline 912. Alternatively, the perimeter channel 910 does not extend to the spline 912. A data device (not shown), such as a radio frequency identification device (RFID), containing production data is embedded within the door. The production data may include a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program (CNC) or a
combination thereof. The protective layers 902, door panels 904 and 906 and splines 912 are attached together using an adhesive. The one or more protective layers 902 and splines, 912 are coated with an intumescent material 818. Note that the door panels 904 and 906 can also be coated with the intumescent material 818 or other fire retardant or resistant material. Note also that an adhesive having fire retardant properties can be used.
Referring now to FIGURE 10, a flow chart illustrating a method 1000 to manufacture a fire rated door in accordance with one embodiment the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 1002. Then in block 1004, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) attaching a second door panel to the splines and the first door panel using an adhesive and (c) applying pressure to the door slab to bond the splines and the door panels together. A perimeter channel is cut in the sides of the door slab in block 1006. Note that the perimeter channel can extend to the spline. An intumescent banding material and an exterior banding to conceal the intumescent banding material are inserted into the perimeter channel in block 1008. Alternatively, the stiles and door panels can contain intumescent or fire resistant materials. A specified design is routed into each door panel of the door slab in block 1010. One or more primer coats are applied to the door slab in block 1012. The primer coats can be applied using an electrostatic powder coating process. Alternatively, the stiles, door panels and/or primer coats can contain intumescent or fire retardant/resistant materials. Note also that an adhesive having fire retardant properties can be used. The door slab is machined to receive a set of hinges and lockset hardware in block 1014. Note that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps.
Now referring to FIGURE 11, a flow chart illustrating a method 1100 to manufacture a fire rated door in accordance with another embodiment the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 1102. Then in block 1104, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) inserting one or more protective layers between the stiles, (c) inserting a data device into the door slab, (d) attaching a second door panel to the splines, the protective layers and the first door panel using an adhesive, and (e) applying pressure to the door slab to" bond the splines and the door panels together. The protective layers can be a fire resistant material, a blast resistant material, a
ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. The data device contains production data, such as a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program (CNC) or a combination thereof. A perimeter channel is cut in the sides of the door slab in block 1106. Note that the perimeter channel can extend to the spline. An intumescent banding material and an exterior banding to conceal the intumescent banding material are inserted into the perimeter channel in block 1108. One or more primer coats are applied to the door slab in block 1112. The primer coats can be applied using an electrostatic powder coating process. Alternatively, the protective layers, stiles, door panels and/or primer coats can contain intumescent or fire retardant/resistant materials. Note also that an adhesive having fire retardant properties can be used. A specified design is routed into each door panel of the door slab in block 1110. The door slab is machined to receive a set of hinges and lockset hardware in block 1114. Note that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps.
Referring now to FIGURE 12, a flow chart illustrating a method 1200 to manufacture a fire rated door in accordance with yet another embodiment the present invention is shown. Two longitudinal interior channels are cut into a back side of a door panel in block 1202. One or more protective layers are coated with an intumescent material in block 1204 and the stiles are coated with the intumescent material in block 1206. The protective layers can be a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding, material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof. Then in block 1208, the door is assembled by (a) inserting a spline in each longitudinal interior channel of a first door panel, (b) inserting one or more protective layers between the stiles, (c) inserting a data device into the door slab, (d) attaching a second door panel to the splines, the protective layers and the first door panel using an adhesive, and (e) applying pressure to the door slab to bond the splines and the

door panels together. The data device contains production data, such as a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program (CNC) or a combination thereof. A perimeter channel is cut in the sides of the door slab in block 1210. Note that the perimeter channel can extend to the spline. An intumescent banding material and an exterior banding to conceal the intumescent banding material are inserted into the perimeter channel in block 1212. A specified design is routed into each door panel of the door slab in block 1214. One or more primer coats are applied to the door slab in block 1216. The primer coats can be applied using an electrostatic powder coating process. Alternatively, the protective layers, stiles, door panels and/or primer coats can contain intumescent or fire resistant/retardant materials. Note also that an adhesive having fire retardant properties can be used. The door slab is machined to receive a set of hinges and lockset hardware in block 1215. Note that this method can be implemented using a computer program embodied on a computer readable medium having one or more code segments to instruct a set of machines to perform the steps.
Now referring to FIGURE 13,- a block diagram of a manufacturing line 1300 in accordance with one embodiment of the present invention is shown. A first set of machines 1302 cuts two longitudinal interior channels into a back side ofadoorpanel, A second set of machines 1304 assembles a door slab by inserting a spline in each longitudinal interior channel of a first door panel, attaching a second door panel to the splines and first door panel using an adhesive and applying pressure to door slab to bond the splines and door panels together. A third set of machines 1306 cut a perimeter channel in the sides of the door slab, and insert an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel. A fourth set of machines 1308 route a specified design into each panel of the door slab. A fifth set of machines 1310 apply one or more primer coats to the door. slab.. A sixth set of machines 1312 machine the door slab to receive a set of hinges and lockset hardware. One or more conveyors 1314 interconnect the machines to move the door slabs.
The manufacturing line may also include a seventh set of machines 1316 to cut large sheets of a lignocellulosic substrate, a wood, a wood composite, a medium density
fiberboard or a combination thereof into a door panel. An eighth set of machines 1318 can be used to apply an intumescent coating to the splines and a ninth set of machines 1320 can be used to apply an intumescent coating to the one or more protective layers. The one or more protective layers are inserted between the first door panel and the second panel by the second set of machines 1304. A tenth set of machines 1322 cut the protective layers, such as gypsum board, to the proper size. An eleventh set of machines 1324 prehang and package the doors. The second set of machines 1304 can also a data device into the door slab. The data device provides one or more instructions to control one or more of the machines. As a result, the specified design for the router can be different for successive door slabs moving through the line. Moreover, the data device allows each door slab to be customized to satisfy a purchase order. AH of the machines can be fully automated or semi-automated.
A more specific example of a production process in accordance with the present invention will not be described. The door panels are sawn to rough size from large sheets. The door panels are sized on long edges and grooved for splines or sticks, if necessary. The panels from the previous saw operation are automatically fed into a production line of several machines. The first operation in that line trims the long edges of the panels to a consistent and predetermined size for the product required. This same machine also machines two grooves to accept the aligning splines or sticks.
After the panels leave the machine in the step above, they are coated with a PUR hot melt adhesive, and then assembled into a door slab. This may consist of two door panels with encapsulated locating splines or sticks, an assembly without the splines, or a fire door or other type of assembly with or without splines. The third layer in a fire door assembly consists of a layer of 5/8" or 1/2" thick type C or type X gypsum board. This board may be coated with an intumescent or fire resistant paint or it may have the intumescent ingredients mixed within the gypsum. The splines, if present, may also be coated with the same intumescent or fire resistant paint. It is at this point that the RFID device is inserted internally. This RFID device will store information about the door, identifying it to all subsequent operations, so that the proper machine programs and parameters will be utilized during the processes of manufacturing. After the slab is assembled, it will run through pressure devices to assure a quality bond between the components, and will be automatically stacked down onto roller conveyor.
The next step in the process is to automatically feed the doors from stacks on the roller conveyor into an automated line that will first machine the short sides of the door so that they are parallel and to a specific dimension. The doors are then rotated 90 degrees and fed into a second machine that machines the long sides, giving them a 3 degree relief angle, makes those sides parallel and to proper dimension. These operations will also sand the machined edges to conceal the joint between the panels, and chamfer or radius the edges. When fire rated doors are being produced, the machines will also machine clearance for and install intumescent banding along all four edges, and will also have the ability to install another layer of paintable banding over the intumescent banding, to provide the required appearance of a solid substrate. After the machining, banding and sanding operations, the doors will again be automatically stacked on roller conveyor.
Doors are fed through automated router lines, where the first router machines one side of the door, a second station inverts the door, and another router machines the opposite side before they are automatically stacked.
After the doors have been sized and/or banded, they will be automatically fed from stacks into machine lines that will perform the routing per customer order to give them the desired final appearance of being of raised panel construction and/or carved. The first machine will work on one panel of the door, and when that operation is complete, the doors will be conveyed to a device that inverts itso that it can be introduced to a second machine which will work on the opposite panel. When this operation is complete, the doors will again be automatically stacked on roller conveyor.
The doors are fed through an automated prime coating line, where the top side is finished first, the doors are inverted, and the opposite side is finished. The doors then are fed into a second identical line which applies a second coat to all panels of the doors before they are automatically stacked. The doors are fed one at a time through a process that first-sands the top panel to remove imperfections, denibs (remove whiskers) and cleans, preheats, sprays primer, cures the primer and denibs again. The doors are then inverted and the same steps are performed on the opposite panel, with one additional step: at the end of the process line, the long edges are denibbed. At this point, the doors are automatically sent into a second line which is identical to the first, applying a second coat to all panels. The doors are then automatically stacked on roller conveyor.
Alternatively, the doors are fed through an automated powder coat finish line. The doors are loaded either by hand or by a robot onto racks mounted to an overhead conveyor
system. This conveyor system can be of a line conveyor type or a "power and free" type system. The doors are electrically charged either through contact through the racks/hooks and the conveyor system itself, or a conductive primer coating has been applied. After the doors are loaded onto the racks, they are sent through the preheat process. The preheat mechanism can be via one of three types; IR electric, IR gas catalytic or thermally via . heated air circulation. Care needs to be taken in this process not to heat the doors too quickly, which can cause moisture to be driven to the panel resulting in cracks in the panel of the doors. Another issue could be scorching of the door panel. After preheating, the doors go to the powder application booth. The powder can be applied manually, semi-automatically (where an operator must be present to touch up areas to ensure complete coverage) or automatically. The powder itself can be of three types; theimo cure, low heat thermo cure or UV cure. After the powder is applied, the doors then proceed to the curing process. The curing process is accomplished through the application of heat via IR devices. These IR devices can be of different wavelength for different applications, or they can be of a combination of short, medium and long wavelength to improve the curing properties. At the end of the curing cyple, a UV light source can be utilized for the UV cured powder type. Next in the process is the cool, down tunnel where cool air is circulated to bring the doors down to a temperature where they can' be handled. They are then removed from the conveyor system and stacked, either manually or with a robot. The panels that can be obtained with the above process can range in texture from smooth to rough* and the gloss level can range from low to high gloss.
The doors are fed through an automated machine line where they are prepared for hinges and lock sets as required. After this operation, the doors pass through an automatic inspection station, where they are checked via machine vision and laser inspection/measuring equipment for conformation to standards, and to verify that the doors match the intended specifications recorded on the enclosed RFID chip. They are then automatically stacked and packaged for shipment
This machine line will machine the edges of the doors for the proper hinges and lockset hardware. The doors are automatically fed into and stacked from this process as well. It is after this operation where we may inject the pilot holes for the hinge screws with the chemical to improve the screw holding properties.
Each of these machine lines will receive the instructions for what work is to be performed on each door via the encoded information stored on the embedded RFID device.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification, but only by the claims.

WE CLAIM:
Claim 1: A fire rated door comprising:
a first routable door-sized panel attached back-to-back to a second routable door-sized panel such that two longitudinal interior channels are formed by opposing longitudinal interior channels in the back of each door-sized panel with each formed longitudinal interior channel containing a spline;
a perimeter channel in the sides of the door containing an intumescent banding material;
an exterior banding to conceal the intumescent banding material; and
the first routable door-sized panel and the second routable door-sized panel comprise a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof.
Claim 2: The door as recited in claim 1, further comprising:
one or more protective layers disposed between the first routable door-sized panel and the second routable door-sized panel; and
wherein the one or more protective layers comprise a fire resistant material, a blast resistant material, a ballistic resistant material, a shielding material, a chemical resistant material, a biohazard resistant material, a radiation resistant material, a dampening material, a grounding material or a combination thereof.
Claim 3: The door as recited in claim 2, wherein the one or more protective layers comprise one or more gypsum boards, one or more metallic sheets, one or more lead sheets, one or more Kevlar sheets, one or more ceramic sheets, a layer of urethane foam, a layer of graphite, a wire mesh or a combination thereof.
Claim 4: The door as recited in claim 2, wherein the one or more protective layers contain an intumescent or fire resistant material, or are coated with the intumescent or fire resistant material.
Claim 5: The door as recited in claim 1, wherein the perimeter channel along the longitudinal sides of the door extend to the spline.
Claim 6: The door as recited in claim 1, further comprising a data device containing production data embedded within the door, wherein the production data comprises a date that the door was manufactured, a time that the door was manufactured, an order number, a purchase number, a product identifier, a purchaser identifier, a shift identifier, a personnel identifier, a machine line identifier, one or more specifications for the door, a list of hardware for the door, a size of the door, a style of the door, a routing design identifier, a parts list, an options identifier, a special features identifier, an assembly program or a combination thereof.
Claim 7: The door as recited in claim 1, wherein the splines contain an intumescent or fire resistant material, or are coated with an intumescent or fire resistant material.
Claim 8: The door as recited in claim 1, wherein the first routable door-sized panel and the second routable door-sized panel contain an intumescent or fire resistant material, or are coated with the intumescent or fire resistant material.
Claim 9: A method for manufacturing a fire rated door comprising the steps of:
cutting two longitudinal interior channels into a back side of a first door-sized panel and a second door-sized panel, wherein the door-sized panel comprising a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof;
assembling a door slab by inserting a spline in each longitudinal interior channel of the first door-sized panel, attaching the back side of the second door-sized panel to the splines and the back side of the first door-sized panel using an adhesive and applying pressure to the door slab to bond the splines and the door-sized panels together;
cutting a perimeter channel in the sides of the door slab;
inserting an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel;
routing a specified design into a front side of each door-sized panel of the door slab;
applying one or more primer coats to the door slab; and
machining the door slab to receive a set of hinges and lockset hardware.
Claim 10: The method as recited in claim 9, further comprising the step of applying an intumescent coating to the splines.
Claim 11: The method as recited in claim 9, further comprising the step of:
inserting a data device into the door slab; and
injecting a chemical into one or more screw pilot holes to increase screw holding capacity or pull strength.
Claim 12: The method as recited in claim 9, further comprising the step of inserting one or more protective layers between the first door-sized panel and the second door-sized panel.
Claim 13: The method as recited in claim 12, further comprising the step of applying an intumescent coating to the one or more protective layers.
Claim 14: The method as recited in claim 9, wherein the one or more primer coats include an intumescent material.
Claim 15: The method as recited in claim 9, wherein the one or more primer coats are applied with an electrostatic powder coating process.
Claim 16: A manufacturing line to produce fire rated doors comprising:
a first set of machines to cut two longitudinal interior channels into a back side of a first door-sized panel and a second door-sized panel;
a second set of machines to assemble a door slab by inserting a spline in each longitudinal interior channel of the first door-sized panel, attaching the back side of the second door-sized panel to the splines and the back side of first door-sized panel using an adhesive and applying pressure to door slab to bond the splines and the door-sized panels together;
a third set of machines to cut a perimeter channel in the sides of the door slab, and insert an intumescent banding material and an exterior banding to conceal the intumescent banding material within the perimeter channel;
a fourth set of machines to route a specified design into a front side of each door-sized panel of the door slab;
a fifth set of machines to apply one or more primer coats to the door slab;
a sixth set of machines to machine the door slab to receive a set of hinges and lockset hardware; and
one or more conveyors interconnecting the machines to move the door slabs.
Claim 17: The manufacturing line as recited in claim 16, further comprising a seventh set of machines to cut large sheets of a lignocellulosic substrate, a wood, a wood composite, a medium density fiberboard or a combination thereof into a door panel.
Claim 18: The manufacturing line as recited in claim 16, wherein:
the first set of machines further trims the long edges of the door-sized panels; the perimeter channel along the longitudinal sides of the door slab extend to the
spline; and
the one or more primer coats include an intumescent material.
Claim 19: The manufacturing line as recited in claim 16, wherein the specified design is different for successive door slabs moving through the line.
Claim 20: The manufacturing line as recited in claim 16, wherein each door slab is customized to satisfy a purchase order.
Claim 21: The manufacturing line as recited in claim 16, further comprising an eighth set of machines to apply an intumescent coating to the splines.
Claim 22: The manufacturing line as recited in claim 16, wherein:
the second set of machines further inserts a data device that provides one or more
instructions to control one or more of the machines into the door slab; and all of the machines are automated or semi-automated.
Claim 23: The manufacturing line as recited in claim 16, wherein the second set of machines further inserts one or more protective layers between the first door-sized panel and the second door-sized panel.
Claim 24: The manufacturing line as recited in claim 23, further comprising a ninth set of machines to apply an intumescent coating to the one or more protective layers.
Claim 25: The manufacturing line as recited in claim 16, wherein:
the one or more primer coats are applied with an electrostatic powder coating
process; and
the sixth set of machines further injects a chemical into one or more screw pilot
holes to increase screw holding capacity or pull strength.

Documents:

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Patent Number

279327

Indian Patent Application Number

7917/DELNP/2008

PG Journal Number

03/2017

Publication Date

20-Jan-2017

Grant Date

18-Jan-2017

Date of Filing

19-Sep-2008

Name of Patentee

POLYMER-WOOD TECHNOLOGIES, INC.

Applicant Address

8411 PRESTON ROAD, SUITE 650, DALLAS, TX 75225, U.S.A

Inventors:

#	Inventor's Name	Inventor's Address
1	DANIELS, EVAN, R	11420 CHAUCER DRIVE, FRISCO, TX 75036, U.S.A

PCT International Classification Number

E04C 2/54

PCT International Application Number

PCT/US2007/004605

PCT International Filing date

2007-02-21

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/775,481	2006-02-21	U.S.A.