GB2168024A - Apparatus for transferring e.g. bottles from a pallet - Google Patents

Abstract

The apparatus (1) comprises a framework (14) with a platform (19) to receive a pallet (3) stacked with layers of bottles (2). The platform (19) raises the pallet (3) through incremental steps upwardly and a transfer arm (22) transfers a layer of bottles at a time onto a conveyor belt (4) of bottling apparatus. The platform (19) is driven by a hydraulic ram (20) via chains while the transfer arm (22) is driven by a hydraulic ram (26) via chains. A roller conveyor (7) transfers loaded pallets into the apparatus (1). Empty pallets are transfered by a chain conveyor (150) from the output end (10) of the roller conveyor (7) into a pallet stacker (12). <IMAGE>

Description

SPECIFICATION Apparatus for transferring a product The present invention relates to apparatus for transferring product and in particular, though not limited to apparatus for transferring bottles, for example, empty mineral bottles from a pallet onto a conveyor or the like.

In bottling plants, for example, milk bottling plants, mineral water bottling plants or the like, empty bottles are received on a pallet. Usually, the bottles are stacked in layers very often as high as five or ten layers high. Each layer is supported by the layer immediately below it on a cardboard platform. Usually, the platform is in the form of a lid which extends downwardly over the bottles on which it is resting. It is necessary to transfer the bottles from these pallets onto a conveyor belt or the like for delivery into the bottle filling apparatus.

Various depalletising apparatus have been developed for this, however, all suffer from various disadvantages. In general, they tend to be relatively complex and accordingly usually difficult to operate, prone to breakdown, and also they tend to be relatively expensive. There is therefore a need for apparatus for removing bottles, or indeed, any other product from a pallet or any other support member which overcomes the problems of apparatus known heretofore.

The present invention is directed towards providing such apparatus.

According to the invention there is provided ap paratus for transferring the product from a pallet on to a conveyor or other such device, the apparatus comprising a platform to support the pallet, a transfer arm extending over at least portion of the platform and being movable transversely to move the product from the pallet.

In one embodiment of the invention the transfer arm extends right across the platform preferably, the transfer arm is slidable on a pair of side run ners extending on each side of the platform, and advantageously, the transfer arm is driven by drive means, which preferably is provided by an hy draulic ram.

In another embodiment of the invention the ap paratus comprises a framework having a base and a top portion joined by upstanding side members.

Preferably, the platform is raisable and lowerable within the framework. Advantageously, it is raisa ble and lowerable by a hydraulic ram. Preferably, the platform is raisable through a plurality of incre mental positions.

In another embodiment of the invention the plat form is adapted to support a pallet, and preferably it is adapted to support a pallet with layers of up standing bottles stacked thereon.

In a still further embodiment of the invention a pair of opposing side members are mounted within the framework, the side members being pi voted to the base of the framework and being movable inwardly by rams extending between the side members and the top of the framework to centre the product.

In a still further embodiment of the invention a rear member is provided in the framework, the rear member extending upwardly, inwardly of the framework to centre the products therein.

Advantageously, a pair of doors pivotal on the framework are provided at the front of the framework and extend inwardly/ outwardly enclosed to centre the product within the framework.

In a further embodiment of the invention a feed conveyor is provided to feed pallets into the apparatus. Advantageously, the conveyor extends outwardly at the rear of the apparatus to form an output conveyor to convey empty pallets therefrom.

Advantageously, the platform is recessed into the conveyor to receive pallets therefrom. Preferably, a pallet stacker is provided at the output end of the conveyor to stack empty pallets.

The invention will be more clearly understood from the following description of a preferred embodiment thereof given by way of example only with reference to the accompanying drawings, in which Figure 1 is perspective view of apparatus according to the invention, Figure 2 is perspective view of the apparatus of Figure 1 showing portions of the apparatus in a different position, Figure 3 is a perspective view of portion of the apparatus of Figure 1, Figure 4 is a perspective view of another portion of the apparatus of Figure 1, Figure 5 is a perspective view of a further portion of the apparatus of Figure 1, Figure 6 is a perspective view of a still further portion of the apparatus of Figure 1, Figure 7 is a perspective view of a detail of the apparatus of Figure 1, Figure 8 is a perspective view of another detail of the apparatus of Figure 1, Figure 9 is a perspective view of a still further detail of the apparatus of Figure 1, Figure 10 is a perspective view of a still further detail of the apparatus of Figure 1, Figure 11 is a perspective view of a further detail of the apparatus of Figure 1, Figure 12 is a planned view of further detail of apparatus according to the invention.

Referring to the drawings there is provided apparatus according to the invention indicated generally by the reference numeral 1 for transferring a product, in this case, bottles 2 from a pallet 3 on to a conveyor 4 at a higher level, see figure 6. The bottles 2 are stacked in layers 5 on the pallet 3.

Each layer 5 of bottles is supported by the layer beneath it on a cardboard platform 6 which is effectively in the form of a lid. Pallets 3 stacked with bottles 2 are fed into the apparatus 1 by a roller conveyor 7 with driven rollers 8 and idle roller 9.

The conveyor extends through the apparatus 1 to form an output conveyor 10 to deliver empty pal lets from the apparatus 1. A stacker 12 as will be described below stacks the empty pallets.

The apparatus 1 comprises a framework 14 hav ing a base portion 15, a top portion 16 joined by side walls 17 and a rear wall 18. A platform 19 for receiving the pallets 3 is provided within the framework 14 and is raisable and lowerable by an hydraulic ram 20 mounted to the framework and steel cables 21. This is described below. A transfer arm 22 slidable on a pair of side runners 23 is connected to and driven by a pair of side chains 24 across the platform 19 for removing bottles from the pallet 3. The side chains 24 are driven by a hydraulic ram 26 which is also described in detail below, mounted on the framework 14.

Front and rear uprights 36 and 37 respectively extend between the top and bottom of the framework 14. The front uprights are joined by a top cross member 38 while the rear upright 37 are joined by a top cross member 39. An intermediate cross member 40 also joins the rear uprights 37.

Side members 41 extend between the front and rear cross members 38 and 40 and are formed by a pair of parallel members 42 of box section joined by end members 43. The members 42 form a slot 44 to accommodate the transfer arm 22. The members 41 also extend rearwardly of the machine to direct the bottles 2 onto the conveyor 4. The side runners 23 are supported on the front cross members 38 and the intermediate cross member 40 by brackets not show.

The transfer arm 22 comprises a central member 46 of plastics material for engaging the bottles 2, supported on a transverse member 47 of solid section material see Figure 7. A pair of bearing housings 48 are secured to the transverse member 47 by screws 25. Linear bearings 49 mounted in the housing 48 are slidable on the side runners 23. A link 50 in each side chain 24 is provided to secure the housing 48 and in turn the transverse arm 22 to side chain 24. A screw 51 through the link 50 secures the housing 48 to the link 50.

Referring in particular to Figure 3 each side chain 24 extends around 2 pairs of sprockets, namely, a driven sprocket 55 and an idler sprocket 56. The idler sprockets 56, are rotatable on stubshafts 57 mounted on the framework 14, while the driven sprockets 55 are rotatable on a pair of stub shafts 58 by means of insert bearings (not shown). The shafts 58 are mounted in the framework 14. A second sprocket rigidly connected too the sprockets 55 is rotatable on the shafts 58 and is driven by a chain 60 which is in turn driven by a sprocket 63 on an intermediate draft shaft 61 rotatable in plumber block bearings 62 secured to the framework 14. The intermediate shaft 61 is driven by the ram 26 through a chain 64. One end of the chain 64 is anchored at 65 to the framework 14 and the other end is anchored at 66 also to the framework 14.From the anchorage point 65 the chain extends around a sprocket 68 rotatable on a shaft 69 at the end of the piston rod 70 of the ram 26. The chain 64 then extends around a sprocket 73 fast on the intermediate shaft 61 and from there around the sprocket 74 rotatable on a shaft mounted on the framework 14. The chain then extends around a second sprocket 78 on the shaft 69 of the piston rod 70 to the second anchorage point 66. As the piston 70 extends outwards in the direction of the arrow A the intermediate shaft is rotated in the direction of the arrow B and thus the transfer on 22 is driven in the direction of the arrow C to sweep the bottles thereby transferring bottles from the pallet 3 onto the conveyor 4.When the piston is withdrawn into the ram in the direction of the arrow D the intermediate shaft rotates in the opposite direction thereby returning the transfer arm 22 to the front of the apparatus ready for its next stroke.

Proximity switches 79 are mounted on the top of the framework 14 to sense the two extreme positions of the transfer on 22. A spud 80 on one of the mounting links 50 extends outwardly of the side chain 24 and is sensed by the proximity switches 79.

The platform 19 comprises a pair of side members 84 of solid section material joined by a front and rear transverse member 85 and 86 and an intermediate transverse member 87. Angle members 89 are provided on each side of the front transverse member 85 and the intermediate transverse member 87 and on one side of the rear transverse member 86. A plurality of ball transfer units 90 are mounted on the angle members 89 to allow the pallets to be freely slidable over the platform 19.

The side members 84 terminate in a pair of plate members 94 for releasably connecting the plafform 19 to a pair of carriage members 95 see Figures 4 and 8. Each carriage member 95 is slidable vertically in a box section member 96 and is raisable and lowerable by the ram 20. The members 96 are welded to the near uprights 37. Each carriage member 95 comprises a plate member 98 with a pair of bearing rollers 99 and 100 mounted on each side thereof.

The bearing rollers 99 bear on the front inner face of the box section member while the bearing rollers 100 bear on the rear inner face of the box section member 96. Thus, the front and rear inner faces of the box section member 96 effectively form tracks on which the bearing rollers 99 and 100 run. The plate member 98 extends through a slot 97 in the box section member 96 and 5 terminates in a connecting plate 102 which in turn engages the corresponding plate 94 or of the platform 19. Screws 103 secure the plates 94 and 102 together. A second connecting plate 104 on each carriage member 95 is provided to engage a corresponding connecting plate 105 on a strutt 106 which extends outwardly and is secured to a corresponding side member 84 of the platform 19. This further adds to the rigidity of the platform 19. The steel cables 21 are anchored to the carriage members 95 by anchor brackets 107. The steel cables 21 extend through the box section members 96 and then extend around pulleys 108 and 109 rotatable on shafts (now shown) which are mounted on the framework 14. The cables 21 then in turn extend around pulleys 111 rotatable on a shaft 112 on the piston rod 113 of the ram 20. The other end of the cables 21 are anchored at 114 to the ram 20 by adjusting the screws 115. Thus, when the piston rod 113 of the ram 20 extends outwardly in the direction of the arrow E see Figure 4, the carriage mem bers 95 and in turn the platform 19 is raised. Retraction of the piston 113 lowers the platform 19.

So that the pallet slides easily onto the platform 19 from the roller conveyor 7, recesses 118 are cut in the frame 119 of the roller conveyor to accommodate the transverse members 85, 86 and 87 thereby allowing the top of the platform 19 to sit just below the top of the rollers 8 and 9 of the of the roller conveyor 7.

It will be appreciated that by virtue of the fact that the cables extend from the anchor screws 115 around the piston pulleys 111, that a mechanical advantage of two to one is achieved when driving the platform.

A proximity switch 121 is provided on the framework to indicate when the platform 19 is passing from its second last top position to the top position. A proximity switch 122 indicates when the platform 19 is at its bottom position, see Figure 3.

Sensing means to sense when the bottles have been raised a sufficient incremental distance so that they can be transferred onto the conveyor 4 is provided by a light source and photo cell unit 123 mounted on a bracket 124 at the top of the framework 14. The light source is directed towards a reflector member 125 on a bracket 126 on the opposite side of the framework 14. Light is reflected from the reflector 125 back to the photo cell in the unit 123. The photo cell unit 123 and the reflector 125 are set at such a distance that when the light beam is broken by a cardboard platform 6 the bottles are at the correct height for transfer by the transfer arm 22. On sensing the platform 6 control apparatus (not illustrated) or described stops the ram 20 thereby stopping the platform 19. Such control apparatus will be well known to those skilled in the art.The light of the unit 123 and the reflector 125 are adjustable to accommodate different heights of bottles. Suitable photosensors (not shown) are provided in the apparatus to sense when a full pallet is fully entered in the apparatus.

A pair of inner side walls 130, see Figure 11 are provided on each side of the apparatus 1 within the framework 14. The side walls 130 are mounted on up standing members 131 which are pivotally connected at 132 to the base 15 of the framework 14. The side walls 130 are pivoted inwardly and outwardly around the pivot 132 by means of hydraulic rams 133 mounted between the side walls 130 and the framework 15. Pivotting the side walls inwardly facilitates centring the pallet and in turn the bottles on the platform 19. An inner rear wall 135 is also mounted within the framework 14 and is slightly inclined inwardly, upwardly to further facilitate centring the pallet and in turn the bottle on the platform 19. A pair of doors 136 are mounted on a pair of pivot shafts 137 which are rotatably mounted in the top cross member 38 and the base 15 of the framework 14.An arm 138 extends from the pivot shaft 137 and is connected to a hydraulic ram 139 for openinga and closing the doors 136.

The doors are also slightly inclined upwardly, inwardly to facilitate in centring the pallet and in turn the bottles 2. A safety guard 140 formed by a framework 141 and wire mesh 142 is provided to prevent any pallets falling over off the conveyor 7 and injuring an operator.

Outer side panels 143 and rear panel 145 are secured to the framework 14 for safety. The rams 20 and 26 are mounted in a casing 145 with a door 146.

A portion 147 at the end of the rear panel 144 and rear wall 135 are removed to permit an empty pallet to exit on the output portion 10 of the roller conveyor 7. The output conveyor 10 extends for a sufficient distance so that the pallets progressing along the conveyor 10 clear the apparatus 1. Pallets on the output conveyor 10 are transferred into the pallet stacker 12 by a pair of chains 150. Three pairs of dogs 151 on the chains 150 engage the pallets 3 and transfer them into the stacker 12. The chains 151 extend around sprockets 152 on an idler shaft 153 and the drive shaft 154. a drive shaft 154 is driven by an electric motor 156 through a chain and sprocket drive 157. A platform 158 in the stacker 12 receives and raises the pallets in the stacker 12. A scissors lift 159 raises the platform 158. A hydraulic ram (not shown) operates the scissors lift 159.Two members 160 which effec tivelyform dogs on opposing sides 161 of the stacker 12 engage and retain the lower most pallet as it is raised by the platform 158.

In use, pallets 3 stacked with bottles 2 are fed into the apparatus 1 by the roller conveyor 7. Prior to a pallet being transferred into the apparatus 1 the platform 19 is lowered so that it recesses into the conveyor 7. On being transferred into the apparatus doors 136 close. The side walls 130 point inwardly and the platform 19 is then raised the first incremental distance by the ram 20. A cardboard lid 6 on blocking the photo cell unit 123 the platform 19 is stopped having advanced its first incremental distance. An operator removes the cardboard lid 6 from the bottles and the transfer arm 22 is then driven in the direction of the arrow C by the ram 26 thereby transferring bottles 2 from the pallet 3 to the conveyor 4.At the end of its stroke the transfer arm 22 is then returned by the ram 26 to the front of the apparatus and the platform is then raised through its next incremental distance to offer up the next layer of bottles 2 to the transfer arm 22 for transfer again on to the conveyor 4. When all the layers of bottles 2 have been transferred from the pallet 3 onto the conveyor 6 the platform 19 is then lowered to recess into the roller conveyor 7. The side walls 130 are pivoted outwardly, and the rollers 8 of the conveyor 7 are activated, to convey a new pallet in and to convey the empty pallet out through the opening 157 into the output side of the conveyor 7.

The operation commences all over again. On activation of the conveyor 7 the stacker platform 158 raises a pallet in the stacker 12 from the previous cycle of the apparatus. When the platform 158 returns to its bottom position the chains 150 are activated and the dogs convey the last empty pallet into the stacker 12. Simultaneously with the platform 158 returning to its bottom position the next cycle of the apparatus commences.

It will be appreciated that while the apparatus has been described as having a platform driven by a hydraulic ram, any other means for driving the platform could be used, for example, the cables could be raised and lowered by an electric motor a pneumatic ram or the like. Indeed, in certain cases it is envisaged that a pneumatic or hydraulic 5 ram could be connected directly to the platform for raising and lowering. It will also of course be appreciated that while a particular arrangement of cables has been used in lowering the platform any other arrangement of cables, indeed, chains or other flexible members could be used.

Similarly, it will be appreciated that means other than hydraulic ram could be used for driving the transfer arm, for example, a pneumatic ram, electric motor or any other drive means. It will also of course be appreciated that other arrangements of drive chains could be used. Needless to say any other means of connecting the transfer arm to the side chains could be used. Further, it is envisaged in certain cases that the transfer arm could be directly driven by an hydraulic or pneumatic ram. It will of course be appreciated that while the transfer arm has been described as extending across the platform, this is not necessary it need only extend over a portion of the platform in certain cases. Further, it would be appreciated that the transfer arm could transfer the pallet from one side of the apparatus to the other rather than front to back.Of course, this will readily be apparent to those skilled in the art. Similarly, instead of delivering the bottles from front to back with the apparatus, they could be delivered from back to front.

It will also of course be appreciated that while particular shapes and configuration in construction of platform have been described, platforms of any other shape or construction could be provided. Indeed, in certain cases it is envisaged that the ball bushes may be dispensed with, although needless to say, they do have considerable advantage in accommodating alignment of the pallet and bottles in the apparatus.

It will also of course be appreciated that in certain cases that the input and output roller conveyor could be dispensed with altogether and in which case the pallets would be fed manually into the apparatus. In certain cases, it is envisaged that conveyors other than roller conveyors could be used for transferring the pallets. It will of course be appreciated in certain cases that the product could be mounted on other means besides a pallet. For example, solid base or the like. Needless to say, it will also be appreciated that the platform itself could be provided by a solid base. It is also envisaged that in certain cases that the side walls which are pivoted inwardly aligning the product may be dispensed with.Similarly, in certain cases it is envisaged that the rear wall may be upright instead of slightly inclined and similarly the doors may be upright instead of slightly inclined.

It will of course be appreciated that in certain cases it is not necessary for the apparatus to have a platform which is raisable and in certain cases the platform may be fixed.

Needless to say, it is not necessary for the apparatus to deliver the bottles onto a conveyor, the bottles could be delivered onto any other suitable means or device.

While the apparatus has been described with a stacker for stacking empty pallets, it will of course be appreciated in certain cases that this part of the apparatus may be dispensed with. Further, it will be appreciated that the sensing means could be dispensed with altogether indeed, in certain cases all of the sensing means could be dispensed with and the operations of the apparatus could be manually controlled. In certain cases it is also envisaged that the front doors may be dispensed with.

While a particular shape and construction of the apparatus has been described it will be readily apparent to those skilled in the art that many other constructions and shapes could be provided without departing from the scope of the invention.

It will also of course be appreciated that the apparatus could be used for transferring any type of product from a pallet or the like.

In certain cases, it is envisaged that the ends of the strokes of each of the hydraulic rams may be cushioned. Such cushioning may be provided by an external valving arrangement or alternately may be provided by an in-built valving arrangement.

Claims (43)

1. Apparatus for transferring a product from a pallet to a conveyor or other such device, the apparatus comprising a platform to support the pallet, a transfer arm extending over at least portion of the platform and being movable transversely to move the product from the pallet.

2. Apparatus as claimed in claim 1 in which the transfer arm extends right across the platform.

3. Apparatus as claimed in claim 1 or 2 in which the transfer arm is slidable on a pair of side runners extending on each side of the platform.

4. Apparatus as claimed in any preceding claim in which drive means are provided to drive the transfer arm.

5. Apparatus as claimed in claim 4 in which at least one side chain extends longitudinally of one of the side runners around a pair of spaced apart sprockets, and connecting means are provided on the chain to connect the transfer arm to the chain for driving the transfer arm.

6. Apparatus as claimed in claim 5 in which a pair of side chains are provided, a side chain being provided adjacent each side arm runner.

7. Apparatus as claimed in any of claims 4 to 6 in which the drive means is provided by an hydraulic ram.

8. Apparatus as claimed in claim 7 in which a sprocket of each side chain is driven by the ram.

9. Apparatus as claimed in claim 8 in which the hydraulic ram drives an intermediate shaft which in turn drives a drive sprocket of each side chains.

10. Apparatus as claimed in claim 9 in which a pair of side by side sprockets independently rotatable are connected to the piston of the ram, a chain extending from an anchorage point on the apparatus about one of said piston sprockets extends fur ther around a sprocket on the intermediate shaft and then extends around an idler sprocket mounted on the ram and further extends around the second piston sprocket and is anchored to the apparatus so that as the ram extends in one direction the chain drives the sprocket on the intermediate shaft and when the piston moves in the reverse direction the intermediate shaft rotates in the opposite direction.

11. Apparatus as claimed in any preceding claim in which proximity switches are provided on the apparatus to detect extreme position of the transfer arm

12. Apparatus as claimed in any preceding claim in which the apparatus comprises of framework having a base portion and a top portion joined by upstanding side members.

13. Apparatus as claimed in claim 12 in which the transfer arm is mounted adjacent the top of the framework.

14. Apparatus as claimed in claim 12 or 13 in which the platform is raisable and lowerable from a position adjacent the base of the framework to a position adjacent the top of the framework.

15. Apparatus as claimed in claim 14 in which the platform is raisable to a plurality of incremental position between the bottom and the top of the framework.

16. Apparatus as claimed in claim 14 or 15 in which the platform is raisable and lowerable by a hydraulic ram.

17. Apparatus as claimed in claim 16 in which the ram is connected to the platform by steel ropes.

18. Apparatus as claimed in any of claims 14 io 17 in which the platform is mounted to at least one carriage member which is slidable vertically on a track.

19. Apparatus as claimed in claim 18 in which a pair of rotatable rollers are provided spaced apart on the carriage member one above the other to engage the runner.

20. Apparatus as claimed in claim 19 in which a pair of tracks are provided, one track to engage one roller and the other to engage the other roller.

21. Apparatus as claimed in claim 20 in which the tracks are formed by the inner faces of a pair of opposing sides of a box section member.

22. Apparatus as claimed in claim 21 in which a longitudinal slot is provided in the box section material to permit the carriage member to extend there through.

23. Apparatus as claimed in any of the claims 18 to 22 in which the platform is releasably connected to the carriage member.

24. Apparatus as claimed in any of claims 18 to 23 in which a pair of carriage members are provided one on each side of the framework.

25. Apparatus as claimed in any of claims 14 to 24 in which sensing means are provided to sense when the product on the platform has the raised to a position so that the transfer arm can transfer the product.

26. Apparatus as claimed in claim 25 in which the sensing means is provided by a light source and a photo cell.

27. Apparatus as claimed in claim 26 in which proximity sensors are provided on the ram to sense when the piston has reached each end of its stroke.

28. Apparatus as claimed in any of claims 12 to 27 in which a pair of opposing side members are provided within the frame work, the side members being pivoted at their lower end to the base of the framework and movable inwardly to centre the product within the framework.

29. Apparatus as claimed in claim 28 in which each side member is pivoted by a hydraulic ram extending between the side member and the framework adjacent the top thereof.

30. Apparatus as claimed in any of claims 12 to 29 in which a rear wall member is provided in the framework, the rear wall member being inclined inwardly upwardly of the framework for centring the product within the framework.

31. Apparatus as claimed in any of claims 12 to 30 in which a pair of front doors are pivotally mounted on the front of the framework to permit access of the product into the apparatus, the front door being slightly inclined inwardly, upwardly of the framework for centring the product in the apparatus.

32. Apparatus as claimed in any preceding claim in which a feed conveyor is provided to convey pallets into the apparatus.

33. Apparatus as claimed in claim 32 in which the platform of the apparatus recesses into the feed conveyor to receive pallets therefrom.

34. Apparatus as claimed in claim 33 in which the feed conveyor extends rearwardly out of the apparatus to deliver empty pallets therefrom.

35. Apparatus as claimed in claim 34 in which a pallet stacker is provided adjacent the apparatus to receive empty pallets from the output conveyor.

36. Apparatus as claimed in claim 35 in which the empty pallets are fed from the output conveyor by a pair of space depart chains dogs thereon to engage and transfer the pallets onto the pallet stacker.

37. Apparatus as claimed in claim 35 or 36 in which the pallet stacker comprises of platform movable from position a to transfer a pallet from the chain to position above the chain.

38. Apparatus as claimed in claim 37 in which side dogs are provided in the pallet stacker to engage pallet on upward transfer by the pallet stacker platform.

39. Apparatus as claimed in any preceding claim in which all bushes are provided on the platform to permit a pallet to slide freely over the platform.

40. Apparatus as claimed in any preceding claim in which control apparatus is provided to control the operation of the apparatus.

41. Apparatus as claimed in any preceding claim in which the apparatus is adapted to receive a pallet with a plurality of bottles stacked in layers one on top of the other, each layer being supported on the other layer by a cardboard platform resting on the layer immediately below it.

42. Apparatus as claimed in claim 41 in which the sensing means senses the presence of a cardboard platform and on sensing said platform sends a signal to the control apparatus to stop the platform.

43. Apparatus substantially as described herein with reference to and is illustrated in the accompa nying drawings.