Title of Invention	DEVICE AND METHOD FOR JOINING PIPES
Abstract	The present invention discloses a portable device and a method for joining channels/ pipes that forms a part of an assembly at customers end by using the present invention in order to avoid the damages during transportation of the whole panel frame. The device is used for locking an inner pipe into an outer pipe. The device comprises a bending punch that applies a force on the outer pipe having projections such that the projections are locked into the cavities of the inner pipe and the pipes are thus joined firmly.

Title of Invention

DEVICE AND METHOD FOR JOINING PIPES

Abstract

The present invention discloses a portable device and a method for joining channels/ pipes that forms a part of an assembly at customers end by using the present invention in order to avoid the damages during transportation of the whole panel frame. The device is used for locking an inner pipe into an outer pipe. The device comprises a bending punch that applies a force on the outer pipe having projections such that the projections are locked into the cavities of the inner pipe and the pipes are thus joined firmly.

Full Text	FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENS RULES, 2003 COMPLETE SPECIFICATION [See section 10, Rule 13] A DEVICE AND A METHOD FOR JOINING PIPES AND/OR CHANNELS; LARSEN & TOUBRO LIMITED, A COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956, WHOSE ADDRESS IS L&T HOUSE, BALLARD ESTATE, MUMBAI - 400 001, MAHARASHTRA, INDIA. THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED. 1 FIELD OF THE INVENTION This invention relates to a device and a method for joining two or more pipes and/or channels of different sizes. BACKGROUND OF THE INVENTION Different pipes/channels of different sizes and/or shapes are joined together to form a pipe assembly. Multiple pipe assemblies may be used in various constructions. For instance, various pipe assemblies may construct a panel frame that can be used in a switchboard assembly. A pipe assembly with several joints being used in a panel-frame should be rigid enough to prevent twisting of the whole structure and any occurrence of failure upon loading. Generally different pipes/channels are joined together using fasteners such as nuts & bolts or rivets. In case of nut & bolt fasteners, there may be a possibility of loosening of nuts over a period of time. This reduces the rigidity of the panel-frames. Further, constructing pipe assemblies by nut & bolt fasteners is quite time consuming. Therefore, rivets may be used that can improve rigidity and reduce the assembling time. However, pneumatic guns are required to fix a rivet. These pneumatic guns need pressurized air, which is a costly affair. Further, if any nail inside the rivet falls during shifting, the riveted joint would fail under loading. As the above-mentioned joints are time consuming and also require some special arrangements, such as pressurized air as in case of riveted joints, panel-frames are usually not assembled at the customers end. They are assembled and then transported in assembled condition to the customer. However, the size and the weight of various constructions like switchboard 2- result in a difficulty of transporting the whole assembled structure from one place to another. Further, there is also a possibility of damage to the aesthetics and the inner subassemblies. Therefore there is a need for a device and a method for providing a rigid yet simple assembly of the whole structure at customer's end within least possible time thereby avoiding the damages during transportation. SUMMARY OF THE INVENTION The object of the present invention is to provide a device and method for joining atleast two channels / pipes that forms a part of an assembly of a panel frame. It is another object of the invention to provide the assembly of a panel frame at customers end in order to avoid the damages during transportation of the whole panel frame. The present invention discloses a portable device for joining an inner pipe and an outer pipe comprising plurality of legs for supporting the device; a support plate attached to said legs; a middle plate adapted between said legs and support plate; multiple clamps; each being attached to corresponding legs for holding the pipes centrally with respect to the device; an eccentric cam pivotally connected to the support plate; a lever mounted on the cam; a bending punch guided in said middle plate; multiple compression springs connected between said cam and the bending punch for maintaining a perpetual contact between said cam and said bending punch; such that the lever is operated to exert pressure on the pipes through the bending punch via said eccentric cam to join and lock the pipes in each other. -3 As per the invention the device joins atleast two pipes of different cross sectional area. The pipe having smaller cross sectional area may be inserted in the other pipe having larger cross sectional area. The inner pipe may include plurality of cavities to accommodate the projections provided in the outer pipe. In other words the projections are bent into cavities to lock the inner pipe into the outer pipe. In an embodiment of the present invention the device is designed such that the bending punch surface that is in contact with the cam is made cylindrical in shape for maintaining a constant line of contact of the cam with the punch whereas the bottom of the bending punch is provided with a projection for actual bending. Further, the eccentric cam profile is designed in such a way that the pressure on the bending punch through the cam increases gradually. The present invention also teaches a method for joining an inner and an outer pipe comprising the steps of: exerting pressure on a lever for transferring said force to a bending punch through an eccentric cam; applying a gradually increasing load on the bending punch; allowing the bending punch to enter into the cavities of atleast one pipe for bending the projections provided on atleast one pipe into said cavities such that the cavities accommodate the projections and the pipes get locked firmly into each other. The method for joining an inner and an outer pipe does not require any separate die to accomplish the bending process since the cavity of the inner pipe is used as a die for bending 4 Other objects, features and advantages of the invention will be apparent from the drawings, and from the detailed description that follows below. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates the schematic view of the device of the present invention. Figure 2 illustrates the schematic view of the pipes and sequence of their joint. Figure 3 illustrates the schematic view of the punch. Figure 4 illustrates the schematic view of the cam. DETAILD DESCRIPTION OF THE PREFERRED EMBODIMENTS A device and a method for joining channels / pipes that forms a part of an assembly of a panel frame is described below to provide a better understanding. However, it should be understood that the present invention is not limited thereto. Those skilled in the art will recognize additional modifications, application and embodiments within the scope thereof and additional fields in which the invention would be of significant utility. The present invention relates to a device, for joining the channel / pipes in less cost and time. The two pipes / channels to be joined are usually of different shapes including rectangular shape and cross-section of different sizes. The dimensional difference between small section pipe / channel & large section pipe / channel is such that the former can easily slide into the latter. The difference in the two is such that inner pipe cannot rotate once put inside the larger one. To assemble the pipes, projections are provided 5 on outer pipe and corresponding cavities / slots are provided on the inner pipe. These projections are bent into cavities to lock the two pipes in each other. To form the above-mentioned joint a compact device is developed that can be placed on the cross sectional area of two pipes to be joined such that the smaller pipe (8) is placed inside the larger (9) and the whole assembly is placed on a base plate (15). The device of the present invention as shown in Figure 1, comprises at least two support legs (1) and atleast two L'shaped clamps (18) attached to said support legs (1) with help of pivot pins (19) for enabling the pipes to get located centrally with respect to the device. The L'shaped clamps (18) are free to rotate on said pivot pins and can be locked in their respective slots (16), provided on the base plate (15). The support legs (1) are clamped to a support plate (4) via a middle plate (3) with the help of alien screws (12). An eccentric cam (5) is pivoted on a stud (21) fixed to the support plate (4). A bending punch (2) herein after referred to as punch, is guided in the middle plate (3) and is kept floating. Two return springs are connected between the stud (21) and a pin (20) fixed to the punch (2). Thus, the punch is always in positive contact with the cam. The cam is provided with a locator (17) on which a lever (6) can be mounted. The lever (6) is a loose piece & can be attached to the cam (5) with help of the locator (17). In one embodiment of the invention the punch (2) is designed such that the surface in contact with the cam is made cylindrical (14) in shape as shown in figure 1. The cylindrical surface of the punch prevents the line of contact between curved cam & punch to vary within a substantial range of distance from line of movement (13) of the punch. Further, this also prevents the punch from deflecting or tilting from the line of movement (13) thereby avoiding any damage occurring to the middle plate (3) or jamming of punch (2) in the middle plate (3). The cylindrical shape of the top surface of the punch maintains the line of contact of the punch with the cam always at the quadrant, i.e. the highest point of the radius provided for the movement of the cam. The line of contact of the cam with the punch therefore remains almost constant and close to the centre of the punch. Hence, the load acting on the punch is always vertical with least possibility of damage to guiding member or jamming of the punch in the guiding member. Further, in an embodiment of the invention, the eccentric cam profile is designed in such a way that the load on the punch increases gradually. Preferably are plurality of different radii provided on the cam (5) viz. Larger Radius (r1), Smaller Radius (r2) and Relief Radius (r3). At the starting of the load application, the radius is largest (r1). This radius rolls on the cylindrically shaped top surface of punch to start its downward movement. Due to larger radius the applied load increases gradually. The movement of the punch is fast in this case. The smaller radius (r2) follows the larger radius (r1) and the relief radius (r3) precedes the larger radius (r1). When the punch is about to enter the cavity in smaller pipe by bending the projections on the larger pipe, the smaller radius (r2) starts. The force exerted by cam on the cylindrical shaped surface of punch increases, the punch slowly starts to bend the particular projection in larger pipe into the respective cavity of the smaller pipe. The bending takes place against the edge of smaller pipe. It is completed when the maximum eccentricity of the cam is reached. As the small radius starts to roll on the surface of the 7 punch, it further pushes the punch in downward direction and the punch performs the bending operation. The movement of the punch is less in this case as compared to the earlier, but the load applied is very high. In this way the load increases gradually as the punch moves in downward direction and is always vertical. The punch is held in the bottom most position of the smaller radius to get the bottoming effect. Thus, both the pipes get assembled and locked in each other. The third radius is provided for the relief. Figure 2(a) to 2(c) illustrates the stage-wise assembly / formation of the joint. Small pipe (8) is provided with cavities (10) and large pipe (9) is provided with respective projections (11). The small pipe is slide into the large pipe as shown in figure 2(b), in such a way that the projections and cavities perfectly match with each other. Figure 2(c) shows final assembly of the two pipes after bending. Figure 3 illustrates the details of punch. The top surface of punch is provided with a cylindrical (14) profile. Projection provided at the bottom of the punch is used for actual bending. Figure 4 shows a schematic view of cam (5). The cam is provided with three different radii viz. r1, r2 and r3 for proper actuation of the punch. The locator (17) is fixed at the top of the cam. The lever (6) is a loose item. At the time of actuation of cam, the lever (6) is attached to the locator. The advantage of this device that it can be operated manually with very less effort and without any help of external source of power e.g. electric power supply, pressurised air. The device is compact in size and light in weight. Hence, it is easy to carry it to any place. 8 The present invention also discloses a method for assembling the pipes of rectangular section by means of bending. The bending is done manually by applying force through mechanical linkages without help of any power press or fly press. The method for joining the pipes comprises the steps of placing two pipes to be joined on a base plate (15) in such a way that the pipe having smaller cross sectional area (8) is inside the pipe having larger cross sectional area (9); placing the device of the invention on said pipes for allowing them to get self-located at the centre space between support legs (1) provided in the device; releasing two 'L' shaped clamps (18); allowing the 'L' shaped clamps (18) to enter the respective slots (16) provided in the base plate (15) by means of gravity for locking the pipes. The method for joining the pipes further comprises the steps of exerting force on lever (6) manually for transferring said force to the bending punch (2) through the eccentric Cam (5); applying a gradually increasing load on the punch (2); allowing the punch (2) to enter into the cavity of pipe (8) having smaller cross sectional area such that said cavity accommodates the projection provided in the pipe (9) having larger cross sectional area; releasing the two pipes (8 & 9) with each other by means of the tension spring (7); releasing the load on the lever (6) for bringing the lever (6) to its original position; lifting the clamps (18) for releasing the device; and moving the device to another position for another bending. In this invention, the bending process is done without using any separate die. The device of the present invention is designed such that smaller section rectangular pipe is used as a die for bending. The larger pipe is 9 provided with projections & the smaller section pipe has slots / cavities corresponding to the projections. Edges of these slots act as die edge for bending and take the whole bending load. Hence, the device provides an advantage of accomplishing bending process without using any separate die. The foregoing description of the invention has been described for purposes of clarity and understanding and not to limit the invention to the precise form as disclosed. Various other modifications may be possible within the scope and equivalence of the appended claims. 10 WE CLAIM 1. A portable device for joining an inner pipe and an outer pipe comprising: plurality of legs (1) for supporting the device; a support plate (4) attached to said legs (1); a middle plate (3) adapted between said legs (1) and support plate (4); multiple clamps (18); each being attached to corresponding legs (1) for holding the pipes centrally with respect to the device; an eccentric cam (5) pivotally connected to said support plate (4); a lever (6) mounted on the cam (5); a bending punch (2) guided in said middle plate (3); multiple compression springs adapted between said cam and the punch for maintaining a perpetual contact between said cam (5) and said bending punch (2); such that the lever (6) is operated to exert pressure on the pipes through the bending punch (2) via said eccentric cam (5) to join and lock the pipes in each other. 2. A portable device for joining inner pipe and an outer pipe as claimed in claim 1 wherein the outer pipe includes plurality of projections. 3. A portable device for joining inner pipe and an outer pipe as claimed in claim 1 and claim 2 wherein inner pipe includes plurality of cavities to accommodate the projections of said outer pipe. 11 4. A portable device for joining inner pipe and an outer pipe as claimed in claim 1, 2 and 3 wherein said projections are bent into cavities to lock the pipes into each other. 5. A portable device for inner pipe and an outer pipe as claimed in claim 1 wherein the bending punch surface that is in contact with the cam is cylindrical in shape thereby maintaining a constant line of contact of the cam with the punch. 6. A portable device for joining an inner pipe and an outer pipe as claimed in claim 1 wherein the bottom of the bending punch is provided with a projection for actual bending. 7. A portable device for joining inner pipe and an outer pipe as claimed in claim 1 wherein the eccentric cam profile is designed in such a way that the pressure on the bending punch through the cam increases gradually. 8. A portable device for joining inner pipe and an outer pipe as claimed in claim 1, wherein said pipes may be joined at customer's end. 9. A method for joining inner pipe and an outer pipe comprising the steps of: exerting pressure on a lever (6) for transferring said force to a bending punch (2) through an eccentric cam (5); applying a gradually increasing load on the bending punch (2); allowing the bending punch (2) to enter into the cavities of the inner pipe (8) for bending the projections provided outer pipe into said cavities such that the cavities accommodate the projections and the pipes get locked firmly into each other. 10. A method for joining inner pipe and an outer pipe wherein the bending is accomplished without using any separate die. 12 11. A method for joining inner pipe and an outer pipe wherein the cavity of the inner pipe is used as a die for bending. Dated this 21st day of November, 2005. FOR LARSEN & TOUBRO LIMITED By their Agent (UMA BASKARAN) KRISHNA &SAURASTRI 13 ABSTRACT The present invention discloses a portable device and a method for joining channels / pipes that forms a part of an assembly of a panel frame. The panel frame can be assembled at customers end by using the present invention in order to avoid the damages during transportation of the whole panel frame. The device is used for locking an inner pipe into an outer pipe. The device comprises a bending punch that applies a force on the outer pipe having projections such that the projections are locked into the cavities of the inner pipe and the pipes are thus joined firmly. 14

Full Text

FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
&
THE PATENS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
A DEVICE AND A METHOD FOR JOINING PIPES AND/OR CHANNELS;
LARSEN & TOUBRO LIMITED, A COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956, WHOSE ADDRESS IS L&T HOUSE, BALLARD ESTATE, MUMBAI - 400 001, MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
1

FIELD OF THE INVENTION
This invention relates to a device and a method for joining two or more pipes and/or channels of different sizes.
BACKGROUND OF THE INVENTION
Different pipes/channels of different sizes and/or shapes are joined together to form a pipe assembly. Multiple pipe assemblies may be used in various constructions. For instance, various pipe assemblies may construct a panel frame that can be used in a switchboard assembly. A pipe assembly with several joints being used in a panel-frame should be rigid enough to prevent twisting of the whole structure and any occurrence of failure upon loading.
Generally different pipes/channels are joined together using fasteners such as nuts & bolts or rivets. In case of nut & bolt fasteners, there may be a possibility of loosening of nuts over a period of time. This reduces the rigidity of the panel-frames. Further, constructing pipe assemblies by nut & bolt fasteners is quite time consuming. Therefore, rivets may be used that can improve rigidity and reduce the assembling time. However, pneumatic guns are required to fix a rivet. These pneumatic guns need pressurized air, which is a costly affair. Further, if any nail inside the rivet falls during shifting, the riveted joint would fail under loading.
As the above-mentioned joints are time consuming and also require some special arrangements, such as pressurized air as in case of riveted joints, panel-frames are usually not assembled at the customers end. They are assembled and then transported in assembled condition to the customer. However, the size and the weight of various constructions like switchboard
2-

result in a difficulty of transporting the whole assembled structure from one place to another. Further, there is also a possibility of damage to the aesthetics and the inner subassemblies.
Therefore there is a need for a device and a method for providing a rigid yet simple assembly of the whole structure at customer's end within least possible time thereby avoiding the damages during transportation.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a device and method for joining atleast two channels / pipes that forms a part of an assembly of a panel frame. It is another object of the invention to provide the assembly of a panel frame at customers end in order to avoid the damages during transportation of the whole panel frame.
The present invention discloses a portable device for joining an inner pipe and an outer pipe comprising plurality of legs for supporting the device; a support plate attached to said legs; a middle plate adapted between said legs and support plate; multiple clamps; each being attached to corresponding legs for holding the pipes centrally with respect to the device; an eccentric cam pivotally connected to the support plate; a lever mounted on the cam; a bending punch guided in said middle plate; multiple compression springs connected between said cam and the bending punch for maintaining a perpetual contact between said cam and said bending punch; such that the lever is operated to exert pressure on the pipes through the bending punch via said eccentric cam to join and lock the pipes in each other.
-3

As per the invention the device joins atleast two pipes of different cross sectional area. The pipe having smaller cross sectional area may be inserted in the other pipe having larger cross sectional area. The inner pipe may include plurality of cavities to accommodate the projections provided in the outer pipe. In other words the projections are bent into cavities to lock the inner pipe into the outer pipe.
In an embodiment of the present invention the device is designed such that the bending punch surface that is in contact with the cam is made cylindrical in shape for maintaining a constant line of contact of the cam with the punch whereas the bottom of the bending punch is provided with a projection for actual bending. Further, the eccentric cam profile is designed in such a way that the pressure on the bending punch through the cam increases gradually.
The present invention also teaches a method for joining an inner and an outer pipe comprising the steps of: exerting pressure on a lever for transferring said force to a bending punch through an eccentric cam; applying a gradually increasing load on the bending punch; allowing the bending punch to enter into the cavities of atleast one pipe for bending the projections provided on atleast one pipe into said cavities such that the cavities accommodate the projections and the pipes get locked firmly into each other.
The method for joining an inner and an outer pipe does not require any separate die to accomplish the bending process since the cavity of the inner pipe is used as a die for bending
4

Other objects, features and advantages of the invention will be apparent from the drawings, and from the detailed description that follows below.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates the schematic view of the device of the present invention.
Figure 2 illustrates the schematic view of the pipes and sequence of their joint.
Figure 3 illustrates the schematic view of the punch.
Figure 4 illustrates the schematic view of the cam.
DETAILD DESCRIPTION OF THE PREFERRED EMBODIMENTS
A device and a method for joining channels / pipes that forms a part of an assembly of a panel frame is described below to provide a better understanding. However, it should be understood that the present invention is not limited thereto. Those skilled in the art will recognize additional modifications, application and embodiments within the scope thereof and additional fields in which the invention would be of significant utility.
The present invention relates to a device, for joining the channel / pipes in less cost and time. The two pipes / channels to be joined are usually of different shapes including rectangular shape and cross-section of different sizes. The dimensional difference between small section pipe / channel & large section pipe / channel is such that the former can easily slide into the latter. The difference in the two is such that inner pipe cannot rotate once put inside the larger one. To assemble the pipes, projections are provided
5

on outer pipe and corresponding cavities / slots are provided on the inner pipe. These projections are bent into cavities to lock the two pipes in each other.
To form the above-mentioned joint a compact device is developed that can be placed on the cross sectional area of two pipes to be joined such that the smaller pipe (8) is placed inside the larger (9) and the whole assembly is placed on a base plate (15). The device of the present invention as shown in Figure 1, comprises at least two support legs (1) and atleast two L'shaped clamps (18) attached to said support legs (1) with help of pivot pins (19) for enabling the pipes to get located centrally with respect to the device. The L'shaped clamps (18) are free to rotate on said pivot pins and can be locked in their respective slots (16), provided on the base plate (15). The support legs (1) are clamped to a support plate (4) via a middle plate (3) with the help of alien screws (12). An eccentric cam (5) is pivoted on a stud (21) fixed to the support plate (4). A bending punch (2) herein after referred to as punch, is guided in the middle plate (3) and is kept floating. Two return springs are connected between the stud (21) and a pin (20) fixed to the punch (2). Thus, the punch is always in positive contact with the cam. The cam is provided with a locator (17) on which a lever (6) can be mounted. The lever (6) is a loose piece & can be attached to the cam (5) with help of the locator (17).
In one embodiment of the invention the punch (2) is designed such that the surface in contact with the cam is made cylindrical (14) in shape as shown in figure 1. The cylindrical surface of the punch prevents the line of contact between curved cam & punch to vary within a substantial range of distance from line of movement (13) of the punch. Further, this also

prevents the punch from deflecting or tilting from the line of movement (13) thereby avoiding any damage occurring to the middle plate (3) or jamming of punch (2) in the middle plate (3).
The cylindrical shape of the top surface of the punch maintains the line of contact of the punch with the cam always at the quadrant, i.e. the highest point of the radius provided for the movement of the cam. The line of contact of the cam with the punch therefore remains almost constant and close to the centre of the punch. Hence, the load acting on the punch is always vertical with least possibility of damage to guiding member or jamming of the punch in the guiding member.
Further, in an embodiment of the invention, the eccentric cam profile is designed in such a way that the load on the punch increases gradually. Preferably are plurality of different radii provided on the cam (5) viz. Larger Radius (r1), Smaller Radius (r2) and Relief Radius (r3). At the starting of the load application, the radius is largest (r1). This radius rolls on the cylindrically shaped top surface of punch to start its downward movement. Due to larger radius the applied load increases gradually. The movement of the punch is fast in this case. The smaller radius (r2) follows the larger radius (r1) and the relief radius (r3) precedes the larger radius (r1). When the punch is about to enter the cavity in smaller pipe by bending the projections on the larger pipe, the smaller radius (r2) starts. The force exerted by cam on the cylindrical shaped surface of punch increases, the punch slowly starts to bend the particular projection in larger pipe into the respective cavity of the smaller pipe. The bending takes place against the edge of smaller pipe. It is completed when the maximum eccentricity of the cam is reached. As the small radius starts to roll on the surface of the
7

punch, it further pushes the punch in downward direction and the punch performs the bending operation. The movement of the punch is less in this case as compared to the earlier, but the load applied is very high. In this way the load increases gradually as the punch moves in downward direction and is always vertical. The punch is held in the bottom most position of the smaller radius to get the bottoming effect. Thus, both the pipes get assembled and locked in each other. The third radius is provided for the relief.
Figure 2(a) to 2(c) illustrates the stage-wise assembly / formation of the joint. Small pipe (8) is provided with cavities (10) and large pipe (9) is provided with respective projections (11). The small pipe is slide into the large pipe as shown in figure 2(b), in such a way that the projections and cavities perfectly match with each other. Figure 2(c) shows final assembly of the two pipes after bending.
Figure 3 illustrates the details of punch. The top surface of punch is provided with a cylindrical (14) profile. Projection provided at the bottom of the punch is used for actual bending.
Figure 4 shows a schematic view of cam (5). The cam is provided with three different radii viz. r1, r2 and r3 for proper actuation of the punch. The locator (17) is fixed at the top of the cam. The lever (6) is a loose item. At the time of actuation of cam, the lever (6) is attached to the locator.
The advantage of this device that it can be operated manually with very less effort and without any help of external source of power e.g. electric power supply, pressurised air. The device is compact in size and light in weight. Hence, it is easy to carry it to any place.
8

The present invention also discloses a method for assembling the pipes of rectangular section by means of bending. The bending is done manually by applying force through mechanical linkages without help of any power press or fly press.
The method for joining the pipes comprises the steps of placing two pipes to be joined on a base plate (15) in such a way that the pipe having smaller cross sectional area (8) is inside the pipe having larger cross sectional area (9); placing the device of the invention on said pipes for allowing them to get self-located at the centre space between support legs
(1) provided in the device; releasing two 'L' shaped clamps (18); allowing
the 'L' shaped clamps (18) to enter the respective slots (16) provided in
the base plate (15) by means of gravity for locking the pipes.
The method for joining the pipes further comprises the steps of exerting force on lever (6) manually for transferring said force to the bending punch
(2) through the eccentric Cam (5); applying a gradually increasing load on
the punch (2); allowing the punch (2) to enter into the cavity of pipe (8)
having smaller cross sectional area such that said cavity accommodates
the projection provided in the pipe (9) having larger cross sectional area;
releasing the two pipes (8 & 9) with each other by means of the tension
spring (7); releasing the load on the lever (6) for bringing the lever (6) to its
original position; lifting the clamps (18) for releasing the device; and
moving the device to another position for another bending.
In this invention, the bending process is done without using any separate die. The device of the present invention is designed such that smaller section rectangular pipe is used as a die for bending. The larger pipe is
9
provided with projections & the smaller section pipe has slots / cavities corresponding to the projections. Edges of these slots act as die edge for bending and take the whole bending load. Hence, the device provides an advantage of accomplishing bending process without using any separate die.
The foregoing description of the invention has been described for purposes of clarity and understanding and not to limit the invention to the precise form as disclosed. Various other modifications may be possible within the scope and equivalence of the appended claims.
10
WE CLAIM
1. A portable device for joining an inner pipe and an outer pipe
comprising:
plurality of legs (1) for supporting the device;
a support plate (4) attached to said legs (1);
a middle plate (3) adapted between said legs (1) and support plate (4);
multiple clamps (18); each being attached to corresponding legs (1) for holding the pipes centrally with respect to the device;
an eccentric cam (5) pivotally connected to said support plate (4);
a lever (6) mounted on the cam (5);
a bending punch (2) guided in said middle plate (3);
multiple compression springs adapted between said cam and the punch for maintaining a perpetual contact between said cam (5) and said bending punch (2);
such that the lever (6) is operated to exert pressure on the pipes through the bending punch (2) via said eccentric cam (5) to join and lock the pipes in each other.
2. A portable device for joining inner pipe and an outer pipe as claimed in claim 1 wherein the outer pipe includes plurality of projections.
3. A portable device for joining inner pipe and an outer pipe as claimed in claim 1 and claim 2 wherein inner pipe includes plurality of cavities to accommodate the projections of said outer pipe.
11

4. A portable device for joining inner pipe and an outer pipe as claimed in claim 1, 2 and 3 wherein said projections are bent into cavities to lock the pipes into each other.
5. A portable device for inner pipe and an outer pipe as claimed in claim 1 wherein the bending punch surface that is in contact with the cam is cylindrical in shape thereby maintaining a constant line of contact of the cam with the punch.
6. A portable device for joining an inner pipe and an outer pipe as claimed in claim 1 wherein the bottom of the bending punch is provided with a projection for actual bending.
7. A portable device for joining inner pipe and an outer pipe as claimed in claim 1 wherein the eccentric cam profile is designed in such a way that the pressure on the bending punch through the cam increases gradually.
8. A portable device for joining inner pipe and an outer pipe as claimed in claim 1, wherein said pipes may be joined at customer's end.
9. A method for joining inner pipe and an outer pipe comprising the steps of: exerting pressure on a lever (6) for transferring said force to a bending punch (2) through an eccentric cam (5); applying a gradually increasing load on the bending punch (2); allowing the bending punch (2) to enter into the cavities of the inner pipe (8) for bending the projections provided outer pipe into said cavities such that the cavities accommodate the projections and the pipes get locked firmly into each other.
10. A method for joining inner pipe and an outer pipe wherein the
bending is accomplished without using any separate die.
12

11. A method for joining inner pipe and an outer pipe wherein the cavity of the inner pipe is used as a die for bending.
Dated this 21st day of November, 2005.
FOR LARSEN & TOUBRO LIMITED By their Agent

(UMA BASKARAN) KRISHNA &SAURASTRI
13

ABSTRACT
The present invention discloses a portable device and a method for joining channels / pipes that forms a part of an assembly of a panel frame. The panel frame can be assembled at customers end by using the present invention in order to avoid the damages during transportation of the whole panel frame. The device is used for locking an inner pipe into an outer pipe. The device comprises a bending punch that applies a force on the outer pipe having projections such that the projections are locked into the cavities of the inner pipe and the pipes are thus joined firmly.
14

Documents:

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Patent Number

269288

Indian Patent Application Number

1448/MUM/2005

PG Journal Number

42/2015

Publication Date

16-Oct-2015

Grant Date

14-Oct-2015

Date of Filing

21-Nov-2005

Name of Patentee

LARSEN & TOUBRO LIMITED

Applicant Address

L&T HOUSE, BALLARD ESTATE, MUMBAI 400 001,

Inventors:

#	Inventor's Name	Inventor's Address
1	GUJAR, RAHUL SATISH	ENGINEERED TOOLING SOLUTIONS, LARSEN & TOUBRO LIMITED, ELECTRICAL & ELECTRONICS DIVISION (EBG), POWAI WORKS (WEST), GATE NO. 1, SAKI VIHAR ROAD, MUMBAI 400 072

PCT International Classification Number

F16L37/18,B25B1/08

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA