Title of Invention

METHOD AND APPARATUS FOR INLINE CUTTING AND STACKING OF THERMOFORMED ARTICLES

Abstract

A method and apparatus for in line cutting and stacking of thermoformed articles consisting of [i] drawing and indexing a sheet element from a sheet storage means; [ii] transporting the drawn sheet to a forming cum cutting station comprising a fixed top platen bearing a male tool and a bottom platen bearing a female die complementary to the male tool; [iii] moving and swiveling the bottom platen with the help of a toggle lever and cam mechanism fitted to the bottom platen, relative to the top platen in four operative positions: (a) in a clamping positin in which the bottom platen clamps a drawn sheet to the top platen (b) a forming position where the bottom platen further bears upon the top platen, the male tool descends towards the female die and the forming air is introduced between the clamped platens; [c] a cutting position in whcih the bottom platen further bears on the top platen to cut webs formed between formed articles from the drawn sheet between the top and bottom platens [d] a stacking position in which the bottom platen bearing the formed and cut articles is swiveled away from the top platen towards the stacking station and the formed and cut articles are pushed into the stacking station for stacking and [iv] stacking the formed and cut articles in a stacking station.

Full Text

FORM-2 THE PATENTS ACT, 1970 COMPLETE SPECIFICATION SECTION 10 TITLE METHOD AND APPARATUS FOR INLINE CUTTING AND STACKING OF THERMOFORMED ART1CI,ES APPLICANTS WONDERPACK INDUSTRIES PVT. LTD. PLOT NO. 12, BOMBAY AGRA ROAD, TALEGAON, IGATPURL PIN: 422 403, DIST. NASI UK, MAHARASHTRA, INDIA, AN INDIAN COMPANY The following Specification particularly describes and-ascertain* the nature of this invention and the manner in which it is to be performed :- A This invention relates to method and apparatus for inline cutting and stacking of thermoformed articles. In particular this invention relates to thermo|orming cum cutting machines having stacking capability. In the prior art thermoforming machines for the production of thin walled containers have a mould platform which works in the vertical direction and the finished articles are ejected at 90 degrees by blowing air or are taken out by the punched web itself. This method does not allow for efficient stacking of the finished articles, wasting a lot of time and labour. The main object of this invention is to envisage a machine that is able to thermoform articles at high speed and which has a built in stacking facility and capability. The thermoforming machine in accordance with this invention is specially designed for producing drinking cups & other articles formed typically out of polystyrene and polypropylene. The machine of this invention is equipped with a cam controlled toggle lever mechanism for mould platen movement driven by a servomotor. Indexing of the sheet element is also through servo drive to achieve high degree of accuracy. Thus an object of this invention is to achieve a controlled and precise acceleration and positioning of all components & functions with assured sharp forming and high closing forces with higher consistent output. A unique feature of this machine is tilting of mould platform for a convenient angle to facilitate direct stacking of products for each cycle. The invention therefore provides for a machine having cam controlled thermoforming cum cutting & stacking operation by toggle/lever mechanism for mould platform with tilting mould feature with stacker. According to this invention there is provided a method for inline cutting and stacking of thermoformed articles consisting of [i] drawing and indexing a sheet element from a sheet storage means; [ii] transporting the drawn sheet to a forming cum cutting station comprising a fixed top platen bearing a male tool and a bottom platen bearing a female die complementary to the male tool; [iii] moving and swiveling the bottom platen with the help of a toggle lever and cam mechanism fitted to the bottom platen, relative to the top platen in four operative positions: (a) in a clamping position in which the bottom platon clamps a drawn sheet to the top platen (b) a forming position where the bottom platen further bears upon the top platen, the male tool descends towards the female die and the forming air is introduced between the clamped platens; [c] a cutting position in which the bottom platen further bears on the top platen to cut webs formed between formed articles from the drawn sheet between the top and bottom platens [d] a stacking position in which the bottom platen bearing the formed and cut articles is swiveled away from the top platen towards the stacking station and the formed and cut articles are pushed into the stacking station for stacking and [iv] stacking the formed and cut articles in a stacking station. According to another aspect of this invention there is provided apparatus for carrying out the inline cutting and stacking of thermoformed articles method in accordance with this invention, which consists of [i] an indexing device for drawing and indexing sheet material from a sheet storage means; [ii] carrier means for transporting the drawn sheet to a forming cum cutting station comprising a fixed top platin bearing a male tool and a bottom platen bearing a female die complementary to the male tool;[iiiJ forming air introducing means cooperating with the top platen [iv] a stacking station where formed articles can be received for stacking [v] a toggle lever and cam mechanism fitted to the bottom platen which is adapted to move and swivel the bottom platen relative to the top platen in four operative positions: (a) in a clamping position in which the bottom platen clamps a drawn sheet to the top platen (b) a forming position where the bottom platen further bears upon the top platen, the male tool descends towards the female die and the forming air introducing means introduces forming air between the clamped platens; [c] a cutting position in which the bottom platen further bears on the top platen, to cut webs formed between formed articles from the drawn sheet between the top and bottom platens [d] a stacking position in which the bottom platen bearing the formed and cut articles is swiveled away from the top platen towards the stacking station and the formed and cut articles are pushed into the stacking station for stacking. 4 The invention will now be described with reference to the accompanying drawings, which illustrates one preferred embodiment of this invention, in which Figure 1 shows the schematic drawing of the machine in accordance with this invention showing the three stage machine having an indexing station, a thermoforming station cum cutting station particularly showing the cam and toggle mechanism; Figures 2 show details of the thermoforming station shown in figure 1 in the clamping cum forming position; Figure 3 shows details of the thermoforming cum cutting station as envisaged in accordance with this invention in the cutting position; Figure 4 shows details of the thermoforming cum cutting station in which the mould is tilted for accessing the stacking mechanism; and Figure 5 shows details of the thermoforming cum cutting station cooperation with the stacking mechanism. Referring to the drawings, there is shown generally a thermoforming cum cutting station with inline stacking means. The thermoforming cum stacking machine of this invention consists of the following stations : > roll unwind station {M} > sheet transportation system {ID,CC} 5 > heating station{TP, BP} > forming & cutting station {TP,BP} > stacking unit {ST} > scrap winder unit {not shown} Figure 1 shows the arrangement for indexing and the details of the thermoforming cum cutting station. The material M is drawn by an indexing device ID and led via a carrier chain CC or any other device to an area between the top platen TP and the bottom platen BP of the forming cum cutting station. Top platen bears the male tool MT and the bottom platen BP the female tool/die FT. The bottom platen BP is movable and swivelable on a toggle lever mechanism TLM as is clearly illustrated consisting of a cam CAM a toggle TG a toggle lever TL a toggle tilting lever TTL and stud S. Roll unwind station : The material M in Roll form is mounted on the backside of the machine. Thermoformable grade i.e. PVC/ hips / PP plastic roll of desired size is loaded here. Feeding of sheet [Min] is automatic. The sheet M is pulled through a slow speed geared motor onto a carrier chain CC, controlled by proximity switch to maintain the sheet sag and to ensure desired feed of the material between top and bottom platens TP and BP of the thermoforming cum cutting station. 6 Sheet transportation system : Indexing of the sheet is done by servomotor [not shown]. The desired length of the sheet advancement can be programmed and stored by a pic. Specially designed duplex sprocket and tooth chain can be used to transport the sheet M. Figure 2 shows the clamping and forming position of the bottom platen BP. The bottom platen BP is toggled from the initial tilted position seen in figure 1 to the position where it moves towards the top platen TP and clamps the sheet M between the two platens. In the forming step the male tool in the form of a plug MT descends towards the female tool FT. Forming air FA is blown in and forming takes place. Figure 3 shows the extreme position of the toggling mechanism where the bottom platen moves further up to perform the cutting operation and separate the formed articles from a web formed between the formed articles. Heating The heating is accomplished by top and bottom infrared ceramic heaters [not shown] placed in the top and bottom platens to ensure constant and even radiation of heat. The heaters are moved pneumatically across the material & individual heater 7 zone control is done by closed loop pid temperature control system through pic. Forming & cutting station F&CM The toggle lever mechanism TLM secured to the bottom platen can consist of heavy-duty die pillar set guided by two sliding blocks with bronze bush and four-guide shaft and toggle mechanism TL, The toggle mechanism consists of cutting toggle lever CTL and tilting toggle lever TTL and it is connected between main die pillar and the camshaft driving a cam CAM. The camshaft [not shown] is directly coupled with a servomotor [not shown] . The 2 pair of cams ( one for tilting toggle lever and other for cutting toggle lever) are used to operate the toggle mechanism, which in turn operates the mould platen movement. Additional buffer cylinders can be also provided to mould platen at both sides to reduce the load on servo motor & also to keep wear off of moving parts to a minimum . Figure 4 shows the final position of the bottom platen. After the cutting operation the bottom platen goes to the mould tilted position. Where one arm of the toggle lever is displaced to tilt the mould platen and align it with a stacker ST. The stacking arrangement is shown in figure 5 where a pusher P in the mould platen [the bottom platen] BP pushes the formed and cut articles to the stacker ST. 8 Stacking unit : ST The stacking unit can typically consist of a sliding block with guide shaft and a stacking mask can be operated by a pneumatic system. The formed articles are pushed directly into the collecting channels by means of an ejector plate provided at the mould frame of the bottom platen and thus stacking of the article takes place automatically. Scrap winding unit : [not shown] The scrap generated after forming and punching can get wound automatically at this station by a geared motor, which can be removed easily , while machine is in operation. This cycle is repeated for the next operation. It will be appreciated that numerous variations of the basic concept can be envisaged without departing from the basic nature and the scope of the invention. We Claim: 1. A method for inline cutting and stacking of thermoformed articles consisting of [i] drawing and indexing a sheet element from a sheet storage means; [ii] transporting the drawn sheet to a forming cum cutting station comprising a fixed top platen bearing a male tool and a bottom platen bearing a female die complementary to the male tool; [iii] moving and swiveling the bottom platen with the help of a toggle lever and cam mechanism fitted to the bottom platen, relative to the top platen in four operative positions: (a) in a clamping position in which the bottom platen clamps a drawn sheet to the top platen (b) a forming position where the bottom platen further bears upon the top platen, the male tool descends towards the female die and the forming air is introduced between the clamped platens; [c] a cutting position in which the bottom platen further bears on the top platen to cut webs formed between formed articles from the drawn sheet between the top and bottom platens [d] a stacking position in which the bottom platen bearing the formed and cut articles is swiveled away from the top platen towards the stacking station and the formed and cut articles are pushed into the stacking station for stacking and [iv] stacking the formed and cut articles in a stacking station 2. Apparatus for carrying out the inline cutting and stacking of thermoformed articles method in accordance with claim 1, which consists of [ij an indexing device for drawing and indexing sheet 10 material from a sheet storage means; [ii] carrier means for transporting the drawn sheet to a forming cum cutting station comprising a fixed top platen bearing a male tool and a bottom platen bearing a female die complementary to the male tool;[iiij forming air introducing means cooperating with the top platen [iv] a stacking station where formed articles can be received for stacking [v] a toggle lever and cam mechanism fitted to the bottom platen which is adapted to move and swivel the bottom platen relative to the top platen in four operative positions: (a) in a clamping position in which the bottom platen clamps a drawn sheet to the top platen (b) a forming position where the bottom platen further bears upon the top platen, the male tool descends towards the female die and the forming air introducing means introduces forming air between the clamped platens; [c] a cutting position in which the bottom platen further bears on the top platen to cut webs formed between formed articles from the drawn sheet between the top and bottom platens [d] a stacking position in which the bottom platen bearing the formed and cut articles is swiveled away from the top platen towards the stacking station and the formed and cut articles are pushed into the stacking station for stacking. 3. A method for inline cutting and stacking of thermoformed articles as described herein with reference to the accompanying drawings. 11 12 4. Apparatus for carrying out the inline cutting and stacking of thermoformed articles as described herein with reference to the accompanying drawings.

Documents:

569-MUM-2001-ABSTRACT(7-6-2002).pdf

569-mum-2001-abstract(granted)-(7-5-2008).pdf

569-mum-2001-cancelled pages(12-12-2003).pdf

569-mum-2001-claims(7-6-2002).pdf

569-mum-2001-claims(granted)-(12-12-2003).doc

569-mum-2001-claims(granted)-(12-12-2003).pdf

569-mum-2001-claims(granted)-(7-5-2008).pdf

569-mum-2001-correspondence(12-12-2003).pdf

569-mum-2001-correspondence(ipo)-(20-05-2004).pdf

569-mum-2001-correspondence(ipo)-(4-6-2008).pdf

569-mum-2001-description(complete)-(7-6-2002).pdf

569-mum-2001-description(granted)-(7-5-2008).pdf

569-mum-2001-description(provisional)-(19-6-2001).pdf

569-mum-2001-drawing(07-06-2002).pdf

569-mum-2001-drawing(19-6-2001).pdf

569-mum-2001-drawing(7-6-2002).pdf

569-mum-2001-drawing(granted)-(7-5-2008).pdf

569-mum-2001-form 1(19-06-2001).pdf

569-mum-2001-form 1(19-6-2001).pdf

569-mum-2001-form 19(12-12-2003).pdf

569-MUM-2001-FORM 19(23-5-2003).pdf

569-mum-2001-form 2(complete)-(7-6-2002).pdf

569-mum-2001-form 2(granted)-(12-12-2003).doc

569-mum-2001-form 2(granted)-(12-12-2003).pdf

569-mum-2001-form 2(granted)-(7-5-2008).pdf

569-mum-2001-form 2(provisional)-(19-6-2001).pdf

569-mum-2001-form 2(title page)-(complete)-(7-6-2002).pdf

569-mum-2001-form 2(title page)-(granted)-(7-5-2008).pdf

569-mum-2001-form 2(title page)-(provisional)-(19-6-2001).pdf

569-mum-2001-form 3(07-06-2002).pdf

569-mum-2001-form 5(07-06-2002).pdf

569-mum-2001-power of attorney(19-06-2001).pdf

569-mum-2001-specification(amended)-(12-12-2003).pdf

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