APPARATUS FOR AUTOMATICALLY STACKING AND SACKING PLASTICS MATERIAL CONCAVE ARTICLES

Abstract: Downstream of magazine (1) having parallel channels (C), in which the stacking is carried out of the trays (V) deliv­ ered from the thermoforming apparatus, matching channels (C1) which are mounted in series on a driven channel-convey­ ing device (15), are set in an aligned close relation with the said channels C. A comb-like pushing teeth assembly (10, 14) is swung upon control, so as to cause its pushing teeth (14) to be inserted into the inlet end of the channels (C) for stacking the trays (V), and is translated so as to cause all the stacks of trays (V) to be simultaneously transferred into the respective channel (C1) on the channel-conveying device (15). The said comb-like pushing teeth assembly (10, 14) is then lowered and returned into its rest position, the channel-conveying device (15) being cyclically actuated so as to have the tray stack-loaded channels (C1) set one at a time in line with a pusher (23) which by being imparted a reciprocating motion, transfers in timed relation the stack of trays (V) on the in-line channel (C1) into an automatic machine (32) which is provided for packing this stack of trays (V) into a continuous sack made from a thermoplastic web.

Description: The invention relates to an apparatus for stacking and sacking concave articles, such as trays, or any like containers of a limited depth, made from foamed plastics foils in a thermoforming apparatus, and the said thermoforming apparatus are provided with multiple molds, which are adapted for thermoforming the concave articles, particularly trays, aligned in more parallel rows. By cutting devices the thermoformed concave articles or trays were up to now separated from the foamed plastics foils, and by cutting and turnover devices the same were then stacked within side-by-side arranged parallel channels. A stacked tray-counting device is provided for cyclically actuating a marking device for marking the last concave article or tray in a stack, whenever this stack is formed by a predetermined number of concave articles or trays. The ejection of a stack of concave articles or trays from each respective channel for stacking the same, was up to now carried out manually by an operator having previously fitted on each one of the said channel outlet ends a sack of plastics material into which the ejected stack of concave articles or trays is inserted as it is driven out of its channel. The packing into sacks of these concave articles or trays was then completed with closing means being manually applied to the sack mouth. The object of the invention is to provide an apparatus particularly for stacking trays, in which the aforementioned sacking operations are entirely automated thanks to the provision of only one tray-sacking machine of known type which is connected thereto, and in which a heat-weldable plastics material web is used. The apparatus of the invention comprises a sack-filling magazine on a channel-conveying device, which is formed by a suitable number of second channels of such a shape and in such an arrangement that the said channels can be set in line with the first channels for stacking the trays, from which they receive the stacks of trays in only one step in which these latter channels are emptied by suitable pushing means which are then neutralized and returned into their cycle-starting position. While in the first channels for stacking the trays the forming of new stacks of trays is being started, the said sack-filling magazine on the channel-conveying device has one of its tray-loaded second channels cyclically set in line by its channel-conveying device with the tray-sacking machine and with a pusher by which a stack of trays to be packed in a continuous sack, is introduced into the said machine. Once the tray-loaded second channels of the sack-filling magazine have been all emptied, the said sack-filling magazine is returned into its in-line condition with the first channels for stacking the trays, for a successive operative cycle to be repeated. The invention, and the advantages arising therefrom, will clearly appear in the following specification of one preferred embodiment thereof, which is shown merely by way of an example in the annexed sheets of drawing, in which: Figures 1 and 2 respectively are a side elevational view and a top plan view of the tray-stacking apparatus according to the invention. Figures 3 and 4 are views in an enlarged scale respectively of the device shown in Figure 1, for driving the tray stacks out of the channels for stacking the trays, and of the pusher shown in Figure 2, for driving the tray stacks out of the sack-filling magazine of the channel-conveying device. Figure 5 is a top plan view of the inlet end of the channels for stacking the trays. Figure 6 is a cross-sectional view of the channels for stacking the trays, taken on line VI-VI in Figure 1. Figure 7 is a front elevational view of the sack-filling magazine on the channel-conveying device, which receives the stacks of trays from the channels for stacking the trays, and cyclically feeds the said tray stacks, one at a time, to the tray-sacking machine. In Figures 1 and 2 there is shown that the apparatus according to the invention, comprises a horizontal magazine 1 formed by a plurality of channels C set in a side-by side parallel relation, into which means of known type will stack in an upstanding position on one of their sides, the trays V delivered from the thermoforming apparatus and the cutting means for separating the trays V from the thermoplastic material web from which they are made. The channels C are each provided at the edges of their sidewalls with longitudinally continuous inward projections 42 of one piece therewith or inserted (see figure 6), made from any suitable material which is such or is so treated that an adequate friction will be exerted on the sides of the trays V. The trays V which are caused to follow the inclined outlet end section of conveyor T, and had their concave part turned downward, come to bear in an oblique arrangement on the inlet end of channels C. The tray-stacking means consist of pushers S which are, for example, actuated by a horizontally arranged pneumatic jack, and are each caused to act in timed relation on the respective trays V, so as to orient these trays vertically and to frictionally insert the same, thanks to the provision of projections 42, into the respective channel C, whereby the trays V are consecutively stacked in the said channels, and are held therein in their upstanding position. Differently from what is contemplated in the known art, the configuration of magazine 1 must now be such that withdrawable pushing means which are provided for driving in timed relation out of the said magazine the tray stacks having been cyclically formed therein, should be each allowed to longitudinally slide in the respective channel C. The details of magazine 1 are clearly shown in Figures 1 and 6 to which reference is now made. The sidewalls 101 of channels C are longitudinally supported by underlying respective beams 2 which at the initial section of the said sidewalls are supported by respective uprights 3 connected to a crosspiece 4 which is made integral with the apparatus frame 5, with the mutual distance between the said uprights 3 being preferably adjustable. Fastened to each beam 2 is also a portion of the bottom wall 201 of each channel C, and the bottom walls 201 of said channels C are each parted into two sections by an elongated, longitudinal median aperture 6, of such a width that the pushing means for driving upon control out of the respective channel C a stack of trays V are each allowed to pass through the said elongated aperture 6. By changing the mutual distance between the uprights 3, the width of channels C is varied so as to each time make the same conformable to the size of the trays V to be stacked. A device 7 for the pushing means to be rectilinearly and reciprocatingly moved, is provided in an intermediate position under the magazine 1, and is arranged parallel to the channels C, and is of a length which is suitably longer than the length of the said magazine. The device 7 is of a type which is available on the market, and comprises a channel-shaped straight body 107 which is secured to the frame 5 of magazine 1 and serves as guide for a small carriage 207 connected to a pneumatic jack for driving the same, and to a belt-and-pulley unit for multiplying its travel, the carriage 207, the pneumatic jack, and the belt-and-pulley unit being all located in the said body 107. The carriage 207 runs under the magazine 1, without interfering therewith, and upon control the said carriage 207 can be moved from its rest position designated by K1, to the position designated by K2 in Figure 1, and vice-versa. As shown in Figures 3, 5, and 6, the carriage 207 has the intermediate portion of a horizontal crosspiece 8 fixed thereto, which is so long as to extend across the magazine 1 substantially throughout the width thereof. By the said carriage 207 which is actuated by the said pneumatic jack through the said belt-and-pulley unit, the crosspiece 8 is imparted a to-and-fro movement of such an extent that the same will be driven lengthwise of, and through the entire floor space occupied by the magazine (1), and will be driven out of the said magazine up to be placed at a suitable distance therefrom. By means of parallel end arms 9, 109 the crosspiece 8 rotatably supports a shaft 10 which is parallel to the said crosspiece, is substantially coplanar thereto, and is turned toward the trays V thermoforming apparatus. At one side of carriage 207, a rotary actuator 11 is mounted by means of a stirrup onto the crosspiece 8, with a crank 12 being keyed onto its shaft 111 and being caused to cooperate with a lever 13 radially connected with shaft 10, the whole assembly being such that the said shaft 10 can be angularly moved upon control over a suitable angle at first in the one direction and then in the opposite direction of rotation. In this embodiment, the pushing means for driving out of magazine 1 the stacks of trays V formed therein, consist of duck neck-shaped equal teeth 14 made from a steel strip, which are secured to shaft 10 in an equispaced, coplanar, side-by-side relation. Depending on the angular position into which the shaft 10 is rotated, the pushing teeth 14 will be located in their rest position below the magazine 1, which is shown by solid lines in Figure 3, or in their active position shown by dash lines in this Figure, in which through the respective, elongated longitudinal apertures 6 in the bottom walls of channels C, the said teeth 14 are each caused to engage a respective channel C. When the pushing teeth 14 are swung into their up position, the said teeth have their flat end portion 114 arranged vertically, and by the said end portion 114 they are each caused to bear against, and to act upon the intermediate area of the internal face of the bottom of the last tray V of a stack formed in the respective channel C. Referring to Figures 1, 2, and 3, there is shown that a suitable number of channels C1, which are associated with the upper part of the sack-filling magazine on the channel-conveying device 15, are set longitudinally and coplanarly in-line with the channels C of magazine 1, the length of channels C1 being substantially equal to the length of the said channels C. Like the channels C, the channels C1 are provided at the edges of their sidewalls with similar longitudinally continuous inward projections 42 of one piece therewith or inserted, for an adequate friction to be exerted on the sides of the trays V being stacked in the said channels C1, whereby also in channels C1 these trays will be frictionally held in their properly stacked upstanding position. The channels C1 may be each made in only one plate piece, or they may be each made in more than one plate piece, whereby their width is adjustable so as to cause the same to conform to the cross-section of channels C. When the channels C1 are made in one piece, these channels can be predisposed for being easily and quickly replaced so as to have the same adapted to the size of trays V. The channels C1 are suitably cantilevered by their end which is turned toward the magazine 1, and are transversely supported at their bottom by the chains 115, 215 of the channel-conveying device 15, which are led over respective pinions 16, 116 keyed onto the ends of a pair of parallel shafts 17, 117, which in turn are supported by a base frame 18, with the tensioning of said chains being adjustable by the means shown at 19 in Figure 7. One of the said shafts, the shaft 17 for example, has its one end connected by means of a positive motion transmission drive, such as a chain-and-pinions unit 20, to a driving unit 21 fitted on the said frame 18, with the chain of unit 20 being stretchable. As seen in Figure 7, the parallel branches of chains 115, 215 of the channel-conveying device 15 are supported by respective stationary straight guides 22, 122, particularly in order to ensure that the upper channels C1 will be held as required in their coplanar and in-line condition to and with the channels C of magazine 1. Still in Figure 7 there is shown that the length of the rectilinear branches of the chains 115, 215 of the channel-conveying device 15 is greater than the width of magazine 1, and is so provided that the said branches will suitably project from the said magazine side on which a straight pusher 23 is arranged, which when in rest position is located outside of the floor space occupied by the channel-conveying device 15, as shown by solid lines in Figure 2. The pusher 23 is located over the ideal horizontal plane containing the bottom of those channels C1 which are associated with the upper branches of the chains 115, 215 of the channel-conveying device 15, and the said pusher is attached to the one end of a suitably long horizontal rod 24 which by its opposite end is made integral with a transverse arm 25 shaped like an upturned "L", which in turn is connected in a cantilevered manner to a small carriage 26 being caused to run with its grooved wheels 27 on a rail 28 secured to one side of a structural shape support 29, and arranged parallel to the said rod 24 and to the longitudinal axis of channels C, C1 (see also Figure 4). The horizontal section of the said upturned L-shaped transverse arm 25 is located over the ideal horizontal plane containing the upper edges of those channels C which are associated with the upper branches of the chains 115, 215 of the channel-conveying device 15, so that the said horizontal section of arm 25 does not interfere with the upper edges of said channels C. The support 29 is carried by a frame 30 which is attached to the base frames 5, 18 of magazine 1 and the channel-conveying device 15. The assembly 28, 29 is so long as to allow the pusher 23 to be moved upon control from its rest position shown by solid lines in Figure 2, to the limit of its active stroke shown by dash lines in this Figure. To be caused to reach this latter position, the pusher 23 is moved through the whole floor space occupied by the channel-conveying device 15, and out therefrom with a suitably long section, as required for the same to be passed through the station 31 in a tray-sacking machine 32, in which a thermoplastic material web is made tubular, and to be positioned downstream of a welding and cutting station 33 in the same machine. Referring to Figures 2, 4, and 7, there is shown that toothed pulleys 34, 134 are rotatably fitted on the ends of the structural shape support 29, with their horizontally arranged shafts being parallel to each other and being perpendicular to the said support. A toothed belt 35 is led over the said pulleys 34, 134, with an integral extension 36 of carriage 26 being fastened to the upper branch thereof. The shaft of one of the said toothed pulleys 34, 134 is keyed onto the slow shaft of a geared motor 37 which runs in either directions of rotation, and may be at two speeds, and is provided for imparting the required reciprocating motion to the aforementioned pusher 23. The return stroke of pusher 23 may be carried out at a higher speed than its forward stroke. As controls for reversing the rotation of unit 37, end-of-stroke microcontacts 38, 138 are provided (Figures 4 and 7), which are fitted on brackets 39, 139 fastened to the structural shape support 29, and are arranged for an alternate cooperation with the two opposite profiles of a cam 40 secured to the extension 36 of carriage 26. The tray-sacking machine 32 is a unit of a type which is available on the market, in which only one roll of a thermoplastic material web is used, which is made tubular and is longitudinally welded in station 31, so that a continuous sack is formed, having the required width dimension for containing a stack of trays V. In station 33 the continuous sack into which a tray stack is packed, is provided with two transverse, relatively close parallel weldings, between which it is cut. Both the welding of the top end of the tray-filled sack portion and the bottom welding of the just formed continuous sack, as well as the separation of the filled sack portion are thus achieved. The operation of the apparatus according to the invention is simple and apparent. Once predetermined stacks of trays V have been formed in channels C, in timed relation the pushing teeth 14 are swung upwardly into the position shown by dash lines in Figures 1 and 3, and are translated into the position shown by K2, whereby the stacks of trays V will be simultaneously trans ferred from channels C into the respective channels C1 being set in line with the said channels C. As seen in Figures 1, 2, and 3, the pushing teeth 14 are caused to partly get into the channels C1, which for this purpose are each formed at the inlet end of the respective bottom wall, with an intermediate opening 41. Once the tray stacks have been simultaneously transferred from channels C into channels C1, the pushing teeth 14 are neutralized and returned into their cycle-starting position, while in channels C of magazine 1 new stacks of trays V are being uninterruptedly formed. During this tray stacks-transferring step, the unit 21 for driving the channel-conveying device 15 is intermittently actuated, whereby a tray-loaded channel C1 comes to be each time set in line with the pusher 23. Such an in-line condition is signalled by a sensor, not shown in the drawings, since this is conceivable and easily practicable by those skilled in the art. In timed relation the motor unit 37 is actuated, whereby the pusher 23 is imparted its reciprocating stroke, as required for transferring the stack of trays V having been set in line therewith, from the respective channel C1 to the tray-sacking machine 32 for packing the said tray stack into a continuous sack of thermoplastic material. Once the pusher 23 has been returned into rest position by a may be faster stroke than its forward stroke, the channel-conveying device 15 is re-actuated, whereby a successive tray-stack-loaded channel C1 comes to be positioned in front of the said pusher 23, the described cycle being repeated until all the previously loaded channels C1 are emptied. On completion of the said cycle, if the channel-conveying device 15 has not yet caused a suitable number of channels C1, which are associated with the upper branches of the chains 115, 215 of the said device 15, to be set in line with the channels C of magazine 1, suitable programming and/or detecting means will automatically restore such an inline condition of channels C1, C, as required for the whole operative cycle as described above, to be repeated.

Claims: An apparatus for automatically sacking stacks of plastics material concave articles, particularly trays, delivered from a thermoforming apparatus with side-by-side arranged multiple molds, characterized by comprising: a horizontal magazine (1) formed by a first plurality of channels (C) arranged in a side-by-side parallel relation, into which pushers (S) of a known type will stack the trays (V) delivered from the thermoforming apparatus, the said trays (V) being stacked in an upstanding position on one of their sides, and the channels (C) for stacking the trays (V) being each formed with friction means (42), whereby the said trays (V) will be frictionally held in the said channels (C), a device (7) provided with multiple pushing teeth (14) which upon control are each caused to bear against, and to act upon the rear side of the respective stack of trays (V), and which are translated lengthwise of the horizontal magazine (1) for stacking the trays (V), so that all the stacks of trays V will be simultaneously discharged from said magazine, a sack-filling magazine which is mounted on a channel-conveying device (15) being actuated transversely to the first channels (C) by a driving unit (21), and is formed by a second plurality of channels (C1) of such a size that is substantially equal to the size of channels (C) of the horizontal magazine (1) for stacking the trays V, the second channels (C1) being set in a side-by-side parallel relation, and being so arranged that a suitable number of said second channels (C1) which come to be located on the upper branch of the channel-conveying device (15), will be longitudinally and coplanarly set in line with, and at a close distance from the said first channels (C) of the magazine (1) for stacking the trays (V), so that the second channels (C1) will be loaded with the stacks of trays being simultaneously driven out of the first channels (C), a driven straight pusher (23) which is located at one side of the magazine (1) for stacking the trays (V), with which the channel-conveying device (15) cyclically sets in line one of the tray stack-loaded second channels (C1) of the sack-filling magazine, so that the pusher (23) being longitudinally moved through the one tray stack-loaded second channel (C1) set in line therewith, will drive the tray stack on the said in-line second channel (C1) into a continuous sack made of a thermoplastic material web, which is formed and is suitably sized in an automatic tray-sacking machine (32) of known type, the said pusher (23) being then returned into its rest position, ready for the described tray-sacking operation to be repeated until all of the channels (C1) of the sack-filling magazine have been all emptied, the second channels (C1) of the sack-filling magazine being then brought again into their in-line condition with the first channels (C) of magazine (1) for stacking the trays (V), as required for the said second channels (C1) to be each loaded again with a successive stack of trays (V). The apparatus according to Claim 1, in which the first channels (C) of the magazine (1) for stacking the trays (V) are preferably so made that the width thereof is adjustable so as to cause the same to conform to the size of the to-be-stacked trays (V), and the said channels (C) are each formed in their bottom wall with an intermediate elongated aperture (6) which extends throughout the length thereof, and is pro vided for the pushing teeth (14) of the device (7) to be moved therethough, so that upon control the said device (7) will transfer the stacked trays (V) from the said magazine (1) into the contiguous second channels (C1) of the sack-filling magazine mounted on the channel-conveying device (15). The apparatus according to Claim 1, in which under the magazine (1) for stacking the trays (V), a crosspiece (8) is horizontally arranged, and the said crosspiece (8) is provided for rotatably supporting by means of end arms (9, 109), a shaft (10) arranged parallel thereto, on which duck neck-shaped, equal pushing teeth (14) are comb-like fitted, one in number for each first channel (C) for stacking the trays (V), which teeth (14) when in rest position lie under the channels (C), and upon control the said teeth (14) are swung upwardly into their active position, to be each inserted into the inlet end of the respective aperture (6) in the bottom wall of said channels (C), with their flat end section (114) bearing against the median area of the bottom of the last-stacked tray (V), the said angularly movable shaft (10) being connected by means of a lever (13) and a crank (12) to a rotary actuator (11) fitted on the said crosspiece (8) which supports this shaft 10. The apparatus according to Claim 3, in which the crosspiece (8) supporting the comb-like pushing teeth assembly (10, 14), which in a withdrawable manner is caused to act on the trays (V) in the first channels of magazine (1) for stacking these trays, has its intermediate portion fastened to a small carriage (207) being caused to run on the straight hollow body (107) of an actuator of known type, in which a pneumatic cylinder-and-piston unit is provided for actuating the said carriage by means of a travel-multiplying means consisting of a belt and pulleys assembly. The apparatus according to Claim 1, in which the second channels (C1) of the sack-filling magazine on the channel-conveying device (15) may be adjusted in width, or the said channels are replaceable so as to make the same conformable to any different size of the trays (V). The apparatus according to Claim 1, in which both the first channels (C) for stacking the trays, and the second channels (C1) of the sack-filling magazine on the channel-conveying device (15) are provided at the upper edges of their sidewalls with longitudinally continuous projections (42) extending inwardly of the said channels, so as to have a friction exterted on the sides of trays (V), whereby these trays are stably held in their stacked position, the said projections (42) being in form of inserts fitted on the channel sidewalls, or being made of one piece therewith, and in this latter case the said projections are roughened by being subjected to a suitable treatment. The apparatus according to Claim 1, characterized in that the bottom walls of the second channels (C1) of the sack-filling magazine on the channel-conveying device (15) are each formed in their end side which is turned toward the magazine (1) for stacking the trays (V), with an intermediate longitudinal opening (41), which is adapted for the duck neck- shaped pushing teeth (14) to be each allowed to enter into, and to be freely moved in the respective channel (C1), so that the said teeth will cyclically feed stacks of trays (V) to the sack-filling magazine on the channel-conveying device (15). The apparatus according to Claim 1, in which the sack-filling magazine on the channel-conveying device (15) is provided with a number of second channels (C1) which is at least twice the first channels (C) of the magazine (1) for stacking the trays (V), so that when the one set of tray stack-loaded second channels (C1) has been emptied, the other set of said second channels (C1) is ready for being set in line, or has been already set in line with the said magazine (1). The apparatus according to Claim 1, in which the sack-filling magazine on the channel-conveying device (15) has a number of second channels (C1) which is at least equal to that of the magazine (1) for stacking the trays (V), and once the said second channels (C1) have been emptied, the same are again moved into alignment with the said magazine (1), owing to the said sack-filling magazine being caused to suitably travel forward or backwards by the channel-conveying device (15).

Inventors: TEMPORIN, CARLETTO GIOVANNI
Applicants: NESPAK S.P.A. SOCIETA GENERALE PER L'IMBALLAGGIO
Application year: 1990
Main classification: B65B5
IPC codes: B65B35