GB2046711A

GB2046711A - Method and apparatus for forming a stack of generally flat articles from a shingled stream

Info

Publication number: GB2046711A
Application number: GB7908404A
Authority: GB
Original assignee: Metal Box PLC
Current assignee: Crown Packaging UK Ltd
Priority date: 1979-03-09
Filing date: 1979-03-09
Publication date: 1980-11-19
Also published as: IE49546B1; IE800476L; GB2046711B

Abstract

Flat articles, for example packets (10) of dehydrated soup to be packaged as a stack in a display carton for retail sale, are passed in shingled relation along a generally horizontal conveyor (13), and discharged in succession into an open-topped receptacle, e.g. a carton or a trough (11) associated with a stack removal pusher, located at or beyond the downstream end of the conveyor so as to form a stack of vertically superimposed articles. Because of the close spacing of the articles as they fall into the receptacle, any disorientation of an individual article sufficient to prevent it from adopting its required position and attitude on the stack is prevented by the articles succeeding and/or preceding it. Spaced batches are defined in the article stream by a restraining hook (31), by an accelerator conveyor raisable through the conveyor (13), or by relative movement of the conveyor (13) and an upstream conveyor (12). <IMAGE>

Description

SPECIFICATION Packaging articles This invention relates to the packaging of articles in containers such as cardboard cartons.

The invention has particular application to the packaging of packets of dehydrated soup in display cartons for the retail trade, but may have wide application where generally flat articles have limited rigidity are required to be packaged in containers in stacks of two or more articles.

One method currently used for packaging soup packets in display cartons is to allow the packets to fall in succession from a horizontal feed conveyor on which the packets are placed so as to adopt vertical positions between the upstanding vanes of a vaned conveyor aiigned with the feed conveyor. A reciprocating pusher comb mounted alongside the vaned conveyor then pushes the packets in successive groups from between the vanes and onto a lifting platform. Each stack of packets which is thereby formed on the lifting platform, is in its turn, compressed by a horizontal acting presser ram, raised by the lifting platform to an elevated position whilst still compressed by the presser ram, and then pushed sideways off the lifting platform into a display carton which is suitably positioned to receive it.

The method briefly described in the preceding paragraph suffers from various drawbacks. In addition to the com-plexity and cost of the apparatus involved, the method suffers from an inherent technical weakness which is incurred by the requirement to manipulate the packets when in vertical positions, that is, with their generally plane faces vertical.

For packaging into the cartons the packets need to be substantially flat and of uniform thickness. To that end they may be passed through a flattening device before they are fed onto the feed conveyor as described above.

However, during the whole time interval between their leaving the feed conveyor and their entering the display carton the packets are vertical and therefore subject to the settlement of their contents towards their bottom edges. The distortion of the packets caused by any such settlement may be reduced when the packets are compressed by the presser ram as described, but nevertheless may cause difficulty with the insertion of the packets in the display carton.

The present invention seeks to overcome or substantially reduce the disadvantages described above, and accordingly provides a method of forming a stack of generally flat articles of limited rigidity, the method comprising passing the articles in shingled relationships along a substantially horizontal conveyor with the leading edges of each article overlapped and overlying the trailing edge of the article preceding, and positioning an open-topped receptacle at the downstream end of the conveyor into which the articles may move in succession from the conveyor, each article moving into the receptable being restrained to a generally horizontal position so that a stack of the articles, vertically superimposed, is formed in the receptacle.

The receptacle may be an open-topped trough along which the formed stack may be pushed for further manipulation and packaging. Alternatively the receptacle may itself be a container into which it is required to package the articles. - The restraint provided for the articles as they move into the receptacle may be by virtue of their shingled relationship with the succeeding article or articles on the conveyor; alternatively or additionally it may be provided by the receptacle and any articles already received within it.

In order that the invention may be more fully understood, various embodiments thereof will now be described by way of example and with reference to the accompanying diagrammatic drawings. In the drawings: Fig. 1 shows a first apparatus in accordance with the invention in plan view and when is use; Fig. 2 is a side elevation of the apparatus of Fig.

1 at the same instant of time as depicted in that Figure; Fig. 3 is a scrap view of the apparatus of Fig. 1 showing the discharging of soup packets into the trough; Fig. 4 is a side elevation of a second apparatus embodying the invention; Fig. 5 similarly shows a third apparatus embodying the invention; Fig. 6 similarly shows a fourth apparatus embodying the invention.

Referring now to Figs. 1 to 3, an apparatus is shown for forming a stack of vertically superimposed packets 10 of a powder or granulate material (e.g. dehydrated soup) in an open-topped receptacle in the form of an elongate trough 11 having a horizontal bottom 20 and front and back walls 21,22.

The apparatus comprises an endless upstream feed conveyor 1 2 and an endless downstream shingling conveyor 1 3 each driven by means not shown. The conveyors are aligned so that their horizontal upper runs move in series relation from right to left as indicated by the arrows. The trough 11 extends transversely of the centre-line of the conveyors and is dispoed for receiving packets 10 falling off the shingling conveyor as is later to be described.

The feed conveyor is driven to circulate about rollers or shafts 14, 1 5 at a constant first speed; the shingling conveyor is selectively drivable about further rollers or shafts 16, 1 7 at a lower speed which is lower than this first speed, or a higher speed which is substantially greater than the first speed.

The packets 10, possibly after passing through a mangle-like device (not shown) to give them a substantially uniform thickness, are fed individually onto the upstream, right hand end of the feed conveyor 12, and pass along that conveyor with a longitudinal, generally regular spacing at an average flow rate of, typically, 120 packets per minute.

From the feed conveyor the packets fall in succession through a small distance onto the upstream end of the shingling conveyor, which at this time is moving at its lower speed. This lower speed is so chosen in relation to the average flow rate and longitudinal dimension of the packets on the feed conveyor that in falling onto the shingling conveyor the packets are given a shingled relationship. As will be seen from Figs. 2 and 3, the shingling is such that the front or leading edge of each packet is overlapped with, and overlies, the backs or trailing edge of the packet in front of it. The packets are shown to be overlapped by approximately 60% of their length, but the degree of overlapping may vary within wide limits, typically within the range 20% to 80%.

After the number of packets required to fill one carton have been placed in shingled relation on the shingling conveyor, the shingling conveyor is quickly accelerated to its higher speed, so carrying the group of packets at a high speed away from the feed conveyor. Moving at this high speed the packets of the group fall in succession off the downstream end of the shingling conveyor so as to form a stack of vertically superimposed packets in the trough 11.

Fig. 3 illustrates the manner in which the packets 10 fall into the trough. As each packet in turn reaches the downstream end- of the shingling conveyor 1 3 the packet in front of it falls away into the trough and so allows it to adopt a horizontal attitude, in face-to-face engagement with the shingling conveyor. In this attitude is driven by the shingling conveyor so as to overhang the downstream end of the conveyor progressively to a greater and greater extent.

Up to the time that the packet in question overhangs the shingling conveyor by 50% of its length, it has no tendancy to tilt downwards at its front end. After that time, however, its centre of gravity is unsupported, but downward tilting of the packet is restrained by the weight of the packets behind it on the conveyor, by virtue of the shingled relationship of the packets. Depending upon the degree of shingling, the horizontal attitude of the packet is substantially maintained until a large part of the length of the packet, typically 80%, overhangs the shingling conveyor. The tilting movement on the package by virtue of its weight then overcomes the restraint provided by any succeeding packets, and the packet falls away into the trough.At its release from the succeeding packets the packet does adopt a downwardly tilted attitude, but because of the restraint provided as described above the angle through which it tilts is small, i.e. 200 of angle or less, and insufficient to prevent the package from taking its desired horizontal attitude on top of the stack in the trough 11 or, if it is the first package of the stack, on the bottom 20 of the trough. The front and back walls 21, 22 of the trough act as guides so to ensure that the packet is correctly located in the fore and aft direction; the bottom of the trough or, as appropriate, the uppermost packet of the stack also assists location by guiding the bottom edge of the packet in the forward direction.In addition if, as depicted in Fig. 3, the packets fall into the trough so that two or more are simultaneously in flight, gross disorientation of an individual packet is largely prevented by interference which occurs between the packet in question and the preceding and/or succeeding packets as they fall down together.

When a complete stack of the packets 10 has been formed in the trough 11, a pusher plate 24 (Fig. 1, 3) is operated by a pneumatic cylinder (not shown) to move the stack horizontally along and out of the trough perpendicularly to the centre line of the conveyors 12, 13. A further pusher plate 25 then moves the stack, preferably after vertical compression by a pneumatically operated compressor plate 27, into a packaging carton 26 which 15 open and suitably disposed to receive it.

The carton is then removed and closed for despatch and sale.

As soon as all the packets of the group have been transferred from the shingling conveyor to the trough, the shingling conveyor is decelerated to its lower speed so as to form the next group of packets in shingled relation on its upper run in the same manner as before. The sequence described above is then repeated.

The acceleration and deceleration of the shingling conveyor, and the operation of the pusher plates 24, 25 and the compressor plate 27 are controlled automatically in a predetermined sequence which is initiated by a counter 30 mounted above the feed conveyor each time the number of packets required to form a group has passed. A further controlling function provided by this sequence control is the operation of a hook member 31 which is mounted adjacent the downstream end of the feed conveyor and which is pivotable between the retracted, inoperative position shown in full line in Fig. 2, and the raised position (shown in broken line) in which it is capable of temporarily holding any package incoming along the feed conveyor.

The hook is raised each time the shingling conveyor is accelerated to its higher speed, and lowered to its retracted position when, subsequently, the shingling conveyor is decelerated as described above after the packets on it have been discharged into the trough 11. By its repeated action the hook therefore introduces a spacing between the groups of packets subsequently formed on the shingling conveyor, and prevents any packet from being transferred from the feed conveyor to the shingling conveyor while the shingling conveyor is operating at its higher speed. At any time the shingling conveyor only carries the packets of a single group; it has a length which is just greater than that required to hold all the packets of a group in their shingled relationship, so that the time of operation of the shingling conveyor at its higher speed is kept to a minimum.

By virtue of this and of the high speed at which the shingling conveyor operates when discharging into the trough 1 ,the temporary disruption in the packet flow caused by the hook member 31 only affects a few (e.g. two) of the packets on the feed conveyor. When they subsequently move onto the shingling conveyor these packets have a greater degree of overlapping than the other packets of the group, but this is insufficient to impair their correct location in the trough as described above.

As each group is being discharged into the trough the last packets of the group are subject to progressively reducing restraint to prevent them tilting downwards. However, correct positioning of each of these packets in the trough 11 is assured by the packets already located there, the uppermost packet in the trough being at this time at a substantially reduced spacing below the down-stream end of the shingling conveyor.

Fig. 4 shows the second apparatus embodying the invention. The apparatus can be considered as a modification of the apparatus of Figs. 1 to 3 with the spacing between groups of packets introduced by a two-speed intermediate conveyor 1 8 which replaces the hook member 30 and which is disposed between, and in series with, the conveyors 12, 13 for circulation about rollers or shafts 32, 33.

When, as described in relation to the first embodiment, the shingling conveyor 13 operates at its fast speed to move the shingled packages on it into the trough 1 the intermediate conveyor operates at the former, shingling speed of the shingling conveyor, so that the packages oncoming from the feed conveyor 12 are shingled.

However, when the shingling conveyor itself operates at its shingling speed, the intermediate conveyor operates at the speed of the feed conveyor so as to form a continuation of that conveyor for the remaining packets of the group to be formed on the shingling conveyor.

As with the first embodiment, the apparatus of Fig. 4 generates a greater degree of shingling of the leading packets of a group on the shingling conveyor than that of the remaining packets of the group. As before, however, this does not prevent correct location of all the packets of the group in the trough 11.

In order to reduce the differential shingling within a group on the shingling conveyor, the lower, shingling speed of the intermediate conveyor may be made intermediate the shingling speed of the shingling conveyor and the constant speed of the feed conveyor. However, this requires an increased length for the intermediate conveyor, and for that reason may be undesirable.

Fig. 5 shows the third embodiment of the invention to be a further modification of the first embodiment with the spacing between groups of packets introduced on the shingling conveyor itself. In this embodiment the shingling conveyor 1 is driven at a constant, shingling speed which is substantially lower than the constant speed of the feed conveyor 1 2. The shingling conveyor is formed of a plurality of spaced and parallel belts arranged to circulate about rollers or shafts 16, 1 7 for receiving packets 10 from the feed conveyor as in the first embodiment. In contrast with the first embodiment, however, the forward roller or shaft 1 6 is located at a substantial spacing from the trough 11 upstream of the latter.

A continuously driven high speed conveyor 35 is formed of a plurality of spaced and parallel belts intermeshed with those of the shingling conveyor and arranged to circulate about three rollers or shafts 36, 37, 38. Of these, the roller or shaft 36 is located adjacent the trough 11 at a slightly higher level than the upper run of the shingling conveyor 13, the roller or shaft 37 is located below the roller or shaft 1 7 at the upstream end of the shingling conveyor, and the roller or shaft 38 is carried by a carriage (not shown) for movement between a retracted position in which it is located adjacent the downstream end of the feed conveyor (but forward of the rolled or shaft 1 7 of the shingling conveyor) and an advanced position 38A in which is is located adjacent the roller or shaft 1 6 of the shingling conveyor slightly above the upper run of the latter. In addition, a lifting device (not shown) is provided on the carriage and operable to lift the roller or shaft 38, when in its retracted position, from a lowered position 38L to a raised position 38R.

In the lowered position 38L of the roller or shaft 38, the upper run of the high speed conveyor 35 is located below the upper run of the shingling conveyor where they overlap, and the shingling conveyor is therefore able to receive and shingle packets fed onto it from the feed conveyor 12 as described in relation to the first embodiment.

After packets 10 sufficient to form a group have been fed in their shingled relation onto the shingling conveyor, the roller or shaft 38 is lifted by the lifting device to its raised position 38f; so bringing the upper run of the high speed conveyor through and past that of the shingling conveyor.

The shingled packets of the group on the shingling conveyor are therefore made subject to the high speed conveyor, and are carried forward by that conveyor at a high speed for discharge into the trough 11 in the manner previously described in relation to the first embodiment.

As soon as it reaches its raised position 38R the roller or shaft 38 is advanced by the carriage at the speed of the high speed conveyor towards its advanced position 38A. In so doing it correspondingly advances the trailing end of the upper run of the high speed conveyor (which accordingly moves forward just behind the last packet of the group moving into the trough 11), so that the shingling conveyor is vacated for receiving the packets of the next group to be formed. After completing its forward movement the roller or shaft 38 is returned directly to its lowered and retracted position 38L in readiness for a repeat operation upon the next group of packets in the manner described above.

Fig. 6 shows the fourth apparatus embodying the invention. The feed conveyor 12 is, as before driven to circulate at a constant speed about rollers or shafts 14, 1 5. The shingling conveyor has two parts each formed of parallel and spaced endless belts and intermeshed with one another.

The downstream part 1 3A of the shingling conveyor is arranged to circulate about five rollers or shafts 40,41 , 42, 43 and 44 arranged as shown, with its upper run extending horizontally between the rollers or shafts 40, 44. The upstream part 13B of the shingling conveyor (shown in broken line) is arranged to circulate about further rollers or shafts 45 to 48 and the roll; or shaft 44, so that its upper run extends horizontally between the rollers or shafts 44, 48 in alignment with the upper run of the part 13A. It will be seen that the roller or shaft 44 forms the intersection of the upper runs of the conveyor parts 13A, 138.

The rollers or shafts 43, 44 and 45 are mounted on a carriage (not shown) which is horizontally reciprocable in the fore and aft direction between the retracted position shown, and an advanced position in which it is located closely adjacent the roller or shaft 40 defining the downstream end of the part 1 3A adjacent the trough 11.

The two parts of the shingling conveyor are continuously driven so that, with the exception mentioned below, their upper runs move from right to left as shown at the same speed at which packets fed from the feed conveyor 12 are received on them in shingled relation as previously described.

During normal shingling, the carriage is in its retracted position (as shown) and the soup packets are deposited on the downstream part 1 3A of the shingling conveyor. When a group of packets to be packaged has been formed on the part 13A, the carriage is moved at a high speed to its advanced position. The roller or shaft 43 incorporates a sprag clutch which locks at the beginning of the forward movement, so causing the conveyor part 1 3A to mqve forward in unison with the carriage and so deposit the packets on it into the trough 11.

The movement of the carriage to its advance position correspondingly extends the upper run of the upstream conveyor part 13B forward beyond the dropping point from the feed conveyor 12, so that while the packets of the group are being deposited in the trough the first packets of the next group to be formed are deposited in their desired shingled relation on the conveyor part 13B.

This formation of the next group of packets on the conveyor part 13B proceeds until the preceding group of packets has been deposited in the trough. The carriage is then returned to its retracted position, so transferring the packets on the upstream conveyor part 13B to the downstream conveyor part 1 3A and extending the downstream conveyor part 1 3A upstream beyond thedropping point from the feed conveyor 12.

Normal shingling is therefore resumed as previously described to complete the group of packets on the conveyor part 13A. The cycle described above is repeated for succeeding groups of packets.

If desired, the embodiments of Figs. 5 and 6 may include an inhibit arrangement in the power supply for the shingling conveyor and arranged to stop that conveyor if a gap of greater than a predetermined spacing follows a packet on the feed conveyor. Normal operation of the shingling conveyor is resumed when the succeeding packet arrives.

Although all of the described embodiments have provision for introducing a spacing between successive groups of shingled packets to be deposited into the receptacle formed by the trough 11 , this is not essential to the invention. No spacing between successive groups need be introduced if the overall time required for depositing a group into the receptacle is less than the minimum time interval separating the incoming packets.

Thednvention is not limited to the packing of packets of powder or granulate material as particularly described. It may have wide application where generally flat articles, particularly those of limited rigidity, require to be collated in stacks of two or more articles.

Claims

1. A method of forming a stack of generally fiat articles of limited rigidity, the method comprising; passing the articles generally horizontally but in shingled relationship along a conveyor with the leading edge of each article overlapped and overlying the trailing edge of the article preceding, and positioning an open-topped receptacle at or beyond the downstream end of the conveyor into which the articles may move in succession from the conveyor, each article moving into the receptacle being prevented from gross disorientation from a generally horizontal position by the article succeeding and/or preceding it, so that a stack of the articles, vertically superimposed, is formed in the receptacle.

2. A method according to claim 1, wherein the articles are received in non-shingied serial relationship at a first forward speed, and are formed into their shingled relationship by the said conveyor moving at a lower speed than the said first speed.

3. A method according to claim 2, wherein the articles are separated into successive, spaced groups each formed of a plurality of shingled articles, each group forming one stack in the opentopped receptacle, and the open-topped receptacle being replaced or emptied each time a stack has been formed therein.

4. Apparatus for forming a stack of generally flat articles of limited rigidity, the apparatus comprising: a feed conveyor arranged to advance the articles serially in spaced relation, and a shingling conveyor arranged for receiving the articles from the feed conveyor and for advancing the articles at a speed which, in relation to the longitudinal dimension of the articles and their flow rate along the feed conveyor, is such that the articles are placed in shingled relation on the shingling conveyor, the arrangement being such that an open-topped receptacle positioned at or beyond the downstream end of the shingling conveyor may receive the articles in succession, and a stack of the articles, vertically superimposed, may be formed therein, each'article moving into the receptacle being prevented from gross disorientation from a generally horizontal position by the article succeeding and/or preceding it.

5. Apparatus according to claim 4, which includes a said open-topped receptacle positioned at or beyond the downstream end of the shingling conveyor, and a pusher member, operable after a stack of a predetermined number of articles has formed in the receptacle, to move the stack to vacate the receptacle for a succeeding said stack to be formed therein.

6. Apparatus according to claim 4 or claim 5, wherein the feed conveyor is operable at a first; constant speed, and the shingling conveyor is controllably operable at a shingling speed which is lower than the first speed or alternatively at a discharge speed which is substantially greater than the first speed, operation of the shingling conveyor at its shingling speed resulting in shingling of the articles received from the feed conveyor, and operation of the shingling conveyor at its discharge speed resulting in discharge of the articles so shingled for stacking in a said receptacle.

7. Apparatus according to claim 6, which includes a hook member moveable into the path of articles as they move along the feed conveyor and intermittently operable to separate the articles into groups by temporarily impeding the movement along the feed conveyor of the first article or articles of each group, the changes of operation of the shingling conveyor between its said shingling and discharge speeds being in sequential relation to the operation of the hook member so that for each group the articles are placed in shingled relation on the shingling conveyor and are then discharged by the shingling conveyor whilst further deposition of articles of the succeeding group on the shingling conveyor is prevented by the hook member.

8. Apparatus according to claim 6, which includes an intermediate conveyor interposed between the feed and shingling conveyors and arranged to operate at a higher speed when the shingling conveyor is operating at its shingling speed and at a lower speed when the shingling conveyor is operator at its discharge speed, said lower speed being lower than the speed of the feed conveyor and resulting in shingling of the articles received from the feed conveyor, said higher speed being substantially equal to the speed of the feed conveyor whereby the intermediate conveyor then operates as a continuation of the feed conveyor, the alternate operation of the intermediate conveyor at its two speeds resulting in separation of the articles into successive, spaced groups each formed of a plurality of shingled articles.

9. Apparatus according to claim 4 or claim 5, wherein the feed conveyor is operable at a first, constant speed, and the shingling conveyor is operable at a second, constant speed lower than the first speed and such that articles received thereon from the feed conveyor are shingled, the apparatus further including a discharge conveyor arranged periodically to lift the shingled articles from the shingling conveyor and to advance them at a speed substantially greater than said first and second speeds for discharge beyond the downstream end of the shingling conveyor, the discharge conveyor thereby discharging the articles in successive, spaced groups each formed of a plurality of shingled articles.

10. Apparatus according to claim 9, wherein the shingling conveyor and the discharge conveyor each comprise a plurality of spaced and parallel endless belts arranged to circulate about rollers or shafts, the belts of the two conveyors being intermeshed, and the upstream end of the operative run of the discharge conveyor being trained about rollers or shafts mounted on a carriage, to achieve the lifting of the shingled articles from the shingling conveyor and their subsequent discharge, the said carriage being raisabie to bring the operative run of the discharge conveyor above that of the shingling conveyor and thereafter being advanceable, at said high speed and still in its raised position, towards and beyond the downstream end of the shingling conveyor, said high speed movement being accompanied by circulatory movement of the discharge conveyor at the same speed and in the same operative direction.

11. Apparatus according to claim 10, which includes a sprag clutch associated with said carriage-mounted rollers or shafts for causing the said movement of the belts of the discharge conveyor when the carriage is advanced.

12. Apparatus according to claim 4 or claim 5, wherein the feed conveyor is operable at a first, constant speed, and the shingling conveyor comprises upstream and downstream parts arranged in serial relation and operable at a second speed which is low in relation to the first speed so that articles received from the feed conveyor are placed in shingled relation thereon, the intersection between the said upstream and downstream conveyor parts being reciprocable upstream and downstream of the delivery of articles from the feed conveyor and being normally located at a position upstream of the delivery so that the articles from the feed conveyor are received in shingled relation on the downstream conveyor part, the said intersection being periodically movable, in the downstream direction and at a third speed which is substantially greater than said first and second speeds, to a second position downstream of the delivery from the feed conveyor, and subsequently returnable to said first position, each such downstream movement of the intersection causing the temporary delivery of the articles from the feed conveyor to the upstream conveyor part and being accompanied by operation of the downstream conveyor part at the said third speed, the articles received by the shingling conveyor from the feed conveyor being thereby discharged from the downstream conveyor part in spaced groups each formed of a plurality of shingled articles.

1 3. Apparatus according to claim 12, wherein the upstream and downstream conveyor parts are formed as endless, circulatory loops having their respective downstream and upstream ends trained about rollers or shafts mounted on a reciprocable carriage which forms the said intersection, there being provided a sprag clutch associated with the training of the downstream conveyor part on the carriage and arranged, on downstream movement of the carriage at the third speed, to circulate the downstream conveyor part so that its operative run moves in the same direction and at the same speed as the carriage.

14. A method of forming a stack of generally flat articles, substantially as hereinbefore described with reference to the accompanying drawings.

1 5. Apparatus for forming a stack of generally flat articles, substantially as hereinbefore described with reference to Figs. 1 to 3 of the accompanying drawings.

1 6. Apparatus for forming a stack of generally fiat articles, substantially as hereinbefore described with reference to Fig. 4 of the accompanying drawings.

1 7. Apparatus for forming a stack of generally flat articles, substantially as hereinbefore described with reference to Fig. 5 of the accompanying drawings.

18. Apparatus for forming a stack of generally flat articles, substantially as hereinbefore described with reference to Fig. 6 of the accompanying drawings.