GB2182908A

GB2182908A - Method and device for removing a paper tray from a pile

Info

Publication number: GB2182908A
Application number: GB08625331A
Authority: GB
Inventors: Michel Guillaume-Marie Cosquer
Original assignee: AERA SARL
Current assignee: AERA SARL
Priority date: 1985-10-25
Filing date: 1986-10-22
Publication date: 1987-05-28
Also published as: GB2182908B; FR2589137A1; GB8625331D0; FR2589137B1

Abstract

Method and device for removing the top tray (1a) from a pile (P) of paper trays stacked one inside the other. The tray (1a) is removed by means of a multiple suction head comprising a vertically reciprocable sliding block (21) with suction cups (20), the axes of the cups being inclined at an angle relative to the axis (ZZ') passing through the central zone (120) of the bottom of the tray, perpendicularly relative to the said bottom to converge at the centre of the stack: the suction cups (20) create a crease in this central zone, thereby separating the edge of the tray from the remainder of the pile. The angle has a value of between 15 DEG and 40 DEG , preferably 25 DEG - 30 DEG . The suction cups may be deformable bellows with the vacuum achieved by a Venturi tube supplied with compressed air via a solenoid valve (23). The trays may be cake trays and after removal are placed in cake moulds. <IMAGE>

Description

SPECIFICATION Method and device for removing a paper tray from a pile The present invention relates to a method and a device for removing the top tray from a pile of paper trays stacked one inside the other.

Certain cakes, for example fru it ca kes and "Breton cakes", are generally baked in trays made of very fine greaseproof paper, with which they are then sold. In order to make a cake ofthis kind, a papertray is removed from a pile, deposited in a metal mould with a matching shape and filled with cake mix, and the assembly is placed in a baking oven. After baking, the cake is removed from the mould (with the paper tray attached to it) and is packaged ready for sale.

In modern industrial biscuitfactories, most of these operations, in particular baking ofthe cakes, are performed on continuously operating production lines.

The trays used, which consist of veryfine paper, generally have a slightly conical rim which is partially or completely crimped; this crimping effect ensures that the trays have a certain degree of rigidity in thevertical direction andatthesametime allows them to match perfectly the shape ofthe mould during baking. These trays are delivered to the biscu it factories in batches or piles consisting of a large number of trays, for example about thirty of them, stacked one inside the other. The conical and crimped parts of the trays are generally very tightly packed together and stick at the corners, so that it is very difficu It to separate them without deforming or tearing them.Unfortunately, the attempts at automation, made hitherto, have not provided satisfactory results and this delicate and tedious operation is usually performed manually. This obviously gives rise to a serious problem in modern biscuitfactorieswhich are highly automated in other departments; in fact, the lack of efficiency in the tray removing operation lowers substantially the output ofthe cake production line.

The invention proposes to overcome this problem.

This result is achieved, according to the method forming the subject of the present invention, in that a multiple sucking action is provided in the central zone ofthe bottom of the top tray in the pile, thereby creating a crease in this central zone, since the latter is raised so as to separate the edge of the trayfrom the remainder of the pile. According to a particularly interesting feature ofthis method, the multiple sucking action is provided in several directions which converge towards the central zone ofthe bottom of the tray and which are regularly distributed about an imaginary axis passing through this zone, perpendicularly relative to the bottom.

When, more particularly, it is required to remove elongated trays with crimped ends, it is particularly simple and advantageous to provide a double sucking action along axes which are located in the longitudinal plane of symmetry of the tray, symmetrically on either side ofthe imaginary axis passing through the central zone of the bottom ofthe tray, perpendicularly relative to the said bottom; in this case, the angle which each of these two suction axes forms with this imaginary axis perpendicularto the bottom ofthe trays preferably has a value of between 15 and 40 and advantageously ofthe order of 25to 30'.

The device for removing the paper trays, which is also the subject of the present invention, comprises a sliding blockwhich performs a reciprocating movement in the direction ofthe pile of trays, perpendicularly relative to the bottom ofthe latter, this sliding block being provided with a suction head directed towards the trays; this device is characterized in that the said suction head comprises at least two suction cups, the axes ofwhich converge in the direction of the trays, these axes forming an acute angle with the direction of movement of the sliding block.

In an advantageous embodiment, the suction cups are deformable sleeves in the form of bellows, which means that they are able to assume the correct position on the bottom ofall the trays, independently of the height ofthe pile.

The vacuum insidethe suction cups may be achieved very simply by means of a Venturi tu be which is supplied with compressed air by means of a solenoid valve.

In a preferred embodiment, which is particularly suitable for removing elongated trays with crimped ends from a pile arranged horizontally, the sliding block moves along a vertical axis and its suction head comprises a pair of suction cups, the axes of which are located in the longitudinal plane of symmetryofthetrays and are inclined symmetrically on either side ofthe vertical axis along which the sliding block moves.It is possible to arrange this device so that it transfers the trays which have been removed and deposits them individually in cake moulds; for this purpose, the sliding block may be mounted on a carriage which performs a horizontal reciprocating movement transversely relative to the longitudinal plane of symmetry ofthe trays, and the movements of the sliding block and of the carriage are alternated in such a waythatthe suction head has a trajectory in the form of an inverted "U".

The vertical reciprocating movement of the sliding block and the horizontal reciprocating movement of the carriage are advantageously controlled by pneumatic double-action jacks.

This device may be equipped, according to an interesting characteristic feature of the invention, on the one hand, with first means which are designed so as to convey and arrange successive piles of trays beneath the trajectory ofthe suction head, in a position which allows the trays to be removed, and, on the other hand, with second means which are designed so asto convey and arrange, in succession, the moulds beneath the trajectory of the suction head, in a position for receiving the trays.

Other characteristic features and advantages of the invention will emerge from the description and accompanying drawings which illustrate preferred embodiments thereof.

In the accompanying drawings, Figures land 2 are a front view and plan view, respectively, of an elongated tray with crimped ends; Figure 3 shows, in schematic form and in cross-section, a device for removing,from a pile, a tray identical to that shown in Figures 1 and2; FiguresVand sark views similarto that of Figure 3, showing two stages ofthe operation for removing the top tray from the pile; Figure 6shows, in schematic form, a second possible embodiment of a removal device according to the invention, designed to remove a round tray; Figure 7is a frontview showing a plant which is designed to remove trays from a pile and transfer them into baking moulds for cakes, this plant being equipped with a removal device similarto that shown in Figures3to 5;; Figure 8 is a right-hand view, partially sectioned through a transverse vertical plane, ofthe plant shown in Figure 7.

The papertray 1 shown in Figures 1 and 2 is a tray made ofveryfine greaseproof paper; it has a bottom 12, the length L of which is for example 500 millimetres, and the width 1100 millimetres; it has a roughlyvertical peripheral edge 13,the heighth of which is 60 millimetres; at each of the two ends 10of thetray,this raised edge 13 is rounded and crimped; the crimping lines are indicated bythe reference number 11; moreover, the end edges 10 are slighly conical and form an angle angle a with the vertical. On account ofthethinness of its wall, the two side edges ofthetray, which are not crimped, have a tendency to collapse, as can be seen in Figure 2.The reference numbeer 120 indicates the central zone ofthe bottom 12 ofthe tray, and the reference letter (V) indicates the vertical longitudinal plane of symmetry ofthis tray.

Figure 3 shows a pile P of trays 1 stacked one inside the other, from which it is required to remove the top tray 1 a. The device according to the invention, shown in Figure 3, comprises a sliding block2which is movableverticallyso asto perform a reciprocating movement, indicated by the double arrow F.

The sliding block 2, which is positioned above the pile oftrays P arranged horizontally, is provided with a suction head, generally indicated by the reference number2l,which is directed downwards, i.e.

towards the trays. This suction head comprises a pair suction cups 20, the axes X1, X2, of which are both located inthe longitudinal planeofsymmetry (V) ofthe trays; these axes X1 and X2 are inclined symmetrically at an angle a relative to a vertical axis ZZ' passing through the central zone 120 ofthe bottom ofthe trays; these two axes therefore converge in the direction ofthetrays; the angle is, for example of the o rder of 25" to 30".

The suction cups 20 are connected by a suitable pipe 22, via a solenoid valve, to a suction orvacuum device D.

The suction cups 20 have an elastically deformable wall made,forexample,ofrubberorsimilarmaterial and have to shape of bellows.

In orderto remove the top tray la from the pile P, the sliding block 2 is lowered so that the two suction cups 20 are applied against the bottom ofthistray.

The flexibility ofthe suction cups allows them to rest properly on the bottom of the tray 1 a, despite their inclined position and whatever the height of the pile P (see Figure 4).

With the suction cups connected to the suction device D (valve 23 open),the sliding block 2 is raised; the elastic suction cups therefore reassume their initial shape and create a crease in the central zone 120 of the tray 1 a, thereby freeing its two crimped ends 10 from the ends of the pile where they were tightly packed (see Figure 5).

The tray la thus sucked up may obviously then be transferred by means of the sliding blockto any desired location, for example inside a baking mould, as will be seen below, with reference to Figures 7 and 8.

In the variation shown in Figure 6, the device is designed to remove trays 1' which are circular in shape; this device comprises a sliding block 2' which is movable along a vertical axis ZZ' passing through the central zone 120' of the bottom 12' ofthistray; the suction head 21 ' with which the sliding block 2' is equipped comprises 4 suction cups 20' which are arranged in regularfashion around this axis ZZ', such that their axes Y1, Y2, Y3, Y4form a pyramid,the vertex ofwhich is directed towards the tray 1'.

denotes the angle which each of the axes Y1, Y2, Y3 and Y4 of the suction cups 20' forms with the vertical axis ZZ' ofthe sliding block's movements. The operation of removing the tray 1' from a pile is performed in a manner quite similarto that described forthe preceding embodiment: the sliding block 2' is lowered, a vacuum is formed in the suction pads which come into contact with the bottom 12', and the sliding block is raised; this raising action creates a crease in the central zone 120' of the bottom ofthetrayandfreestheannularedge 13'ofthetray, this edge being separated from the edges ofthe remainder of the pile inside which it was tightly packed.

The plant which is shown in Figures7 and 8 comprises a cantilever-type frame 3 with a pair of horizontal bars 30 inside which slideways 31 are formed. A horizontal plate 4, which will subsequently be referred to as a "carriage", is guided so as to slide along the slideways 31. A double-action pneumatic jack7 is mounted on the upper side of the carriage 4; the plunger 70 of the jack mounted on the said carriage passes through the plate 4 and carries, beneath the latter, a sliding block 2. The latter is provided with a suction head 21 consisting of two suction cups 20; the axes X1, X2 Of these suction cups from an acute angle awith the vertical axis ofthe jack plunger 70; these suction cups are bellows made of rubber which is elastically deformable. The distance between the two.suction cups 20, as well as the angle of inclination a of these suction cups, can be adjusted owing to the presence of elongated apertures 24 formed in the sliding block 2.

Thetwo suction cups 20 are connected by a tube 22 to a Venturi tube 24which is supplied bya compressed-air source AC, via a solenoid valve 23.

The carriage 4 has a rear part 40 which is raised vertically and to which the end of a horizontal plunger 80 of a double-action pneumatic jack 8 is connected; the latter is supported bytheframe3.

The travel of the jack 8 is indicated by the reference "d" inFigure8.

The device operating the two jacks 7 and 8, which, forthe sake of clarity, has not been shown in the Figures and the design of which lies within the technical competence of a person skilled in the art, is arranged sothatthe sliding block 2 (and the suction head 21 carried by the latter) describes the trajectory of an inverted "U", the two arms of which are separated bythedistanced.

The plant comprises a first conveyor 6, consisting, for example, of a moving belt mounted on rollers 60 which ensure that the latter is guided and driven stepwise by means which, for the sake of clarity, have not been shown. This conveyor 6 is designed to transport, in stages, piles of trays P1, P2, P3 directly underneath the sliding block 2 when the latter is located at the rear of the carriage (position shown in Figures 8; (V) denotes the vertical plane in which the axes ofthe suction cups 20 are located; this plane coincides with the longitudinal plane of symmetry of the pile of trays P1 which is located in the position where removal of these trays is effected; in this position, the pile P1 rests against a positioning and centring part 62.The plant is equipped with a second conveyor 5 intended to convey metal moulds M, used for baking the cakes, into the position for receiving the trays which have been removed. This conveyor 5 consists, for example, of a moving belt which is continuously driven by means which,for the sake of clarity, have not been shown.

On either side of the belt 5, there are arranged membersforstopping and centring the moulds M; these members comprise a pair of pressure jacks 50 co-operating with bearing stops 51 located on the othersideofthe belt; the plant is also equipped with a devicefor detecting the moulds, for example a photoelectric cell 52.

It will also be notedthatthe sliding block2 has a vertical rod 9 which is provided with a contactor 90 designed to co-operate with a contact 41 integral with the carriage 4; this contactor makes it possible to detect when the sliding block has reached the bottom position.

The longitudinal vertical plane of symmetry ofthe moulds M, when the latter are clamped between the jacks 50 and the stops 51, indicated by (V1), coincides with the vertical plane containing the axis ofthe suction cups 20, when the carriage 4 is in itsforwards position, separated by the distanced from the plane (V).

The plant operates in the following manner: when a pile of paper trays is positioned against the part 62, the automatic operating means of the plant cause the pneumatic jack 7 to extend,thereby causing the sliding block 2 to descend in the vertical plane (V); the suction cups 20 therefore penetrate inside the pile P1 and rest againstthe bottom of the top tray in this pile; when the sliding block 2 is in its lowered position, the contactor 90/41 closes, thereby causing the solenoid valve 23to open; compressed air is then conveyed into the Venturi tube 24, thereby creating a vacuum inside the tubes 22 and a corresponding sucking action inside the suction cups 20; at the same time, the jack 7 retracts, causing the sliding block 2 to move upwards.During this upwards movement, the suction head 21 extracts the top tray from the pile P1, as explained above with reference to Figure 5.

Meanwhile, a mould M is conveyed bythe conveyor belt into the vicinity of the device; when the cell 52 detects the presence of the end ofthe mould M, it sends a signal to the pressure jacks 50, which causesthem to extend and to clampthis mould againstthe stops 51. The mould M is therefore held by these means 50,51 in the position for receiving the tray, despite the continuous forwards movement ofthe belt 5, this belt sliding against the bottom of the mould.

When the sliding block 2 reaches its uppermost position, the jack 8 starts to operate and moves the carriage 4 into its forward position; the sliding block 2 is thus located in the plane (V1), directly above the mould M; atthis point,thejack7startstooperate again and causes the sliding block to move downwards, thereby inserting the tray, which is still held bythe suction head 21, inside the mould M; when the sliding block 2 reaches its lowermost position, the contactor 90/41 causes the closure of the solenoid valve 23 and the corresponding return to atmospheric pressure of the suction cups 20, such that the paper tray is deposited insidethe mould M, at the same time, the jacks 50 retract, releasing the mould containingthetray, which is transported by the belt 50 to the next station where it receives some cake mixture (arrow H, Figure 7).

The movements ofthe sliding block are then reversed, the suction head returning into the plane (V) in orderto pick up the nexttray; the plant is advantageously equipped with a member for detecting the pile P1 when it is located againstthe support piece 62; when the lasttray in this pile has been removed, this detecting member(notshown) causes the conveyor 6 to start operating and the latterbringsa new pile P2 up againstthesupport piece 62.

It will be noted that the device described above can be adapted for different sizes of trays; hence, there are generally two series oftrayswith different lengths: L = 500 mm and L = 250 mm, the other dimensions land h ofthetrays remaining unchanged; experience has shown that, for the longertrays (L = 500 mm), the ideal angleawas of theorderof25 ,while,forshortertrays(L=250 mm), the ideal angle cm was ofthe order of 30"; in ordertochangefrom one angleto another, itis sufficientto alterthe inclination ofthe axes ofthe suction cups 20 by displacing the latter slightly inside the mounting apertures 24 and pivoting them.

It is obvious that the present invention is not limited to the embodiments which have been described simply bywayofexample; on the contrary, it embraces all variations thereof. The number,the arrangementand the angle of inclination ofthesuction cups used depend obviously on the shape and dimensions of the trays concerned.

In addition to the angle of inclination a defined above, it is possible to provide for lateral angular displacement of the converging axes X1, X2, symmetrically on either side of the vertical plane V.

This double displacement improves still furtherthe creasing effect on the bottom ofthe tray. The amplitude ofthe lateral displacement is, for example, ofthe order of 15 relativeto the plane V.

Claims

1. A method for removing the top tray from a pile of papertrays stacked one insidethe other, characterized in that a suitable sucking action is provided in the central zone of the bottom of the tray, thereby creating a crease in this central zone, and in that the latter is raised so asto separate the edge of the tray from the remainderofthe pile.

2. A method according to Claim 1, characterized in thatthe multiple sucking action is provided in several directionswhich converge towards the central zone ofthe bottom of the tray and are regularly distributed about an imaginary axis passing through this zone, perpendicularly relative to the said bottom.

3. A method according to Claim 2, which is designed more particularlyforremoving elongated trays (1) with crimped ends (10), characterized in that a double sucking action is provided along axes (X1, X2) which are situated in the longitudinal plane of symmetryofthetray, symmetrically on either side of the said imaginary axis (ZZ'), with which they form an acute angle (a).

4. A method according to Claim 3, characterized in thatthe said angle (a) has a value of between 15 and 40 and is preferably of the order of 25 to 30".

5. A device for removing the top tray from a pile of paper trays stacked one inside the other, comprising a sliding block which performs a reciprocating movement in the direction ofthe pile, perpendicularly relative to the bottom of the trays, this sliding block being provided with a suction head directed towards the trays, characterized in that the said suction head (21) comprises at least two suction cups, the axes of which (X1, X2, Y1, Y2, Y3, Y4) converge in the direction of the trays, these axes forming an acute angle (our) with the direction of movement (ZZ') ofthe sliding block.

6. A device according to Claim 5, characterized in thatthe suction cups are deformable sleeves in the form of bellows.

7. A device according to Claim or 6, characterized in that the vacuum inside the suction cups is achieved by means of a Venturi tube which is supplied with compressed air via a solenoid valve.

8. A device according to any of Claims 5,6 or7, which is more particularly designed to remove elongated trays with crimped ends from a pile arranged horizontally, characterized in that the said sliding block moves along a vertical axis (ZZ') and in that its suction head comprises a pair of suction cups, the axes ofwhich are situated inthe longitudinal plane of symmetry (V) ofthetrays and are inclined symmetricallyon either side of the said axis (ZZ') at an angle (a) which is between 15 and 40 and is advantageously of the order of 25to 30".

9. A device according to Claim 8, which is designedfortransferring and depositingthetrays individually in cakes moulds, characterized in that the sliding block is mounted on a carriage which performs a horizontal reciprocating movement, transversely relative to the longitudinal plane of symmetry (V) of the trays, the movements of the sliding block and ofthe carriage being alternated in such a waythatthe suction head has a trajectory in the form of inverted "U".

10. A device according to Claim 9, characterized in that the vertical reciprocating movements of the sliding block and the horizontal reciprocating movements of the carriage are controlled by double-action pneumatic jacks.

11. A device according to Claim 8 or9, characterized in that it comprises first means designed to bring and arrange successive piles of trays (P1, P2, P3...) beneath the trajectory ofthe suction head, in a position where the trays can be removed, and second means designed to bring and arrange the moulds (M), in succession, beneath the trajectory ofthe suction head, in a position for receiving the trays.

12. A method for removing thetoptrayfrom a pile of papertrays stacked one inside the other substantially as hereinbefore described by reference to the accompanying drawings.

13. A device for removing the top tray from a pile of paper trays stacked one inside the other, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.