WO2002070348A1

WO2002070348A1 - Device and process for interleaving food products with sheets

Info

Publication number: WO2002070348A1
Application number: PCT/IE2002/000027
Authority: WO
Inventors: James Finbar Lucey
Original assignee: James Finbar Lucey
Priority date: 2001-03-05
Filing date: 2002-03-04
Publication date: 2002-09-12
Also published as: IE20020161A1; IES20010205A2; WO2002070348A8

Abstract

The invention concerns a process for interleaving food products, for example burgers (1), with sheets (30) of material, suitably paper, which comprises feeding the food products (1) along a feed path towards a sheet application station, feeding a sheet (30) of sheet material to the sheet application station, and applying a sheet (30) of material to a surface of the food product (1). The food products are rigid food products, and are conveyed in stack formation, on their edges in a substantially horizontal feed path, with the major surface of the food products disposed in a substantially vertical plane, towards the inlet of a sheet application station. The sheet material (30) is fed to the sheet application station in a substantially vertical orientation and at the sheet application station a face of the foremost food product (1a) is pressed against a sheet (30) of the sheet material.

Description

Title

_DEVICE AND PROCESS FOR INTERLEAVING FOOD PRODUCTS WITH SHEETS

Field of the Invention

The invention relates to an interleaving device for inserting a sheet material, e.g. a sheet of paper, cellophane, plastics or the like, between rigid formed or cut food products. The invention is particularly concerned with apparatus and a process for feeding flat surfaced rigid food bodies to an interleaving station, and for inserting a leaf or sheet of paper between individual bodies. The invention is particularly concerned with a process for conveying and interleaving frozen foods, cut or formed frozen portions, and frozen meat products, such as burgers, patties, portioned steaks and the like. The invention also includes a transport apparatus suitable for conveying or feeding the rigid food bodies to an interleaving device or to a packing and/or loading station.

Background of the Invention

Hamburgers are patties of minced meat which are usually fried or grilled, and are served in bread buns. The term "burger" as used throughout this specification is intended to included hamburgers, beefburgers, vegetarian burgers, meat cakes, patties, and indeed all kinds of food products, such as cut and formed food portions, portioned steaks, which have flat parallel surfaces and are typically frozen for delivery and storage before use.

Burgers are usually prepared by filling minced meat under pressure into cavities in a reciprocating mould plate. The formed burgers are knocked out of the cavities onto a conveyor. The conveyor conveys the burgers through a blast freezer where the burgers are individually quick-frozen. The conveyor then conveys the frozen burgers to a packaging station where the frozen burgers are manually stacked into cartons or the like. The frozen burgers may be conveyed to a patty stacker machine which stacks the burgers on their edges. It is known to interleave burgers by inserting a leaf of paper, typically of square shape, between each individual burger or, alternatively, to insert a sheet of paper between each layer of burgers. The interleaving of the burgers has the advantage that it prevents the burgers from sticking together when defrosted. The interleaves also facilitate separating the thawed burgers.

Where burgers are individually separated by individual sheets of paper, as distinct from stacked layers of burgers, it is known to insert the interleaf at the stage when the burgers are initially formed and before the freezing stage.

A variety of operations on the burger may be desirable between the forming and freezing steps. Thus, interleaving burgers after freezing has a number of advantages in that it will be possible to include these options and still supply interleaved burgers. The burgers may be cooked on line before freezing, or they may be surface flamed to give a barbecue appearance, or they may be branded with a grill mark, or perforated or scored to enhance cooking, or they may require a cheese flavour deposit or a coating such as breadcrumbs or batter, or they may be individually inspected for shape and appearance conformance.

With the known interleaving arrangement, the sheets of paper are inserted between the burgers before freezing to produce a stack of burgers. The stack is then passed through the freezer and the burgers are frozen as a stack. However, there is an advantage in freezing the burgers individually because not only are all the aforementioned advantages obtained but also the individual burgers freeze faster. This results in the formation of smaller ice crystals and there is less damage to the meat structure than is the case when the burgers are frozen as an interleaved stack.

It is also known to interleave burgers individually after freezing. For example, US 3, 772, 040 (Benson et al) discloses a method and a machine for stacking frozen patties with sheets of paper or other suitable material between them, comprising the feeding of the patties in succession in flatwise file formation in a predetermined non- vertical path and through a stack-starting ring at the end of the path where the patties fall into a parallel superposed vertical stack on a table which is lowered step-by-step in timed relation to the feed of the patties, the cutting from the leading end of a roll of material a sheet which is inserted between each falling patty and the next preceding patty on the stack, and pushing of the stack horizontally from the table to a predetermined point such as a conveyor.

For inserting the sheets of paper between the patties, a strip of wax paper is unrolled from a roll by a paper feed mechanism step-by-step to project horizontally beneath each falling patty in timed relation to the feed of the patties. The leading end portion of the strip is severed from the strip to form a sheet, by a cutting blade fitted on the frame of the machine, and a shearing blade pivotably mounted.

The severed loose sheet of paper is inserted transversely into the path of the falling patties so that each patty presses a sheet between itself and the next lower patty in the stack.

The machine of US 3, 772, 040 suffers from the disadvantage that it is excessively complicated and expensive to build. For the method to work satisfactorily the paper sheet must be inserted between falling patties and the timing is difficult to control.

US 3, 991, 168 (Richards et al) discloses a method and apparatus for interleaving frozen food patties with sheets of protective material (e.g., paper), in which at least a spot of an edible "adhesive" material adheres, each protective sheet to a patty. In one embodiment, a spot of a true adhesive (e.g., honey, sugar solution, etc.) is applied to a protective sheet that is subsequently moved into engagement with a frozen food patty. In another embodiment, at least a spot of an edible heat-activated adhesive material at the interface between a protective sheet and a frozen patty is activated by heat applied through the protective sheet. In this instance, the adhesive may be a separate material which is applied to either the protective sheet or the food patty; on the other hand, the adhesive may comprise moisture in the surface portion of the patty. A sheet applicator comprises a rotor with a plurality of arms, each carrying a suction pickup device. The pickup device picks up an individual sheet of paper from a sheet supply hopper. The rotor is rotated to carry the sheet to an adhesive application station, where adhesive is applied to the sheet. The sheet is then carried by the rotor into alignment with a patty on a conveyor, and presses the sheet onto the top surface of the patty. The frozen patties are conveyed to the interleaving station flatwise on a conveyor.

This apparatus suffers from the disadvantages that an adhesive is required to adhere the sheet to the patty, and that the patties have to be advanced to the sheet application station individually, and not in stacks. The Richard device also requires the use of paper that is wide enough and stiff enough to be self-supporting on frame members that are spaced by a distance greater than the maximum dimension of the hamburger patties. Consequently the paper must be substantially wider than the patties with which it is interleaved, particularly if a thin and highly flexible paper is employed. The apparatus also has some tendency toward malfunction, when extremely thin and flexible sheets of paper are used, in that they may occasionally fall from the frame before being engaged by the falling hamburger patty, resulting in a failure to achieve effective interleaving.

US 3, 675, 387 (Lekan) discloses a device for interleaving individual thin, flexible sheets of paper or similar material with a series of relatively thick flat articles (e.g., hamburger patties) as those articles fall flatwise along a defined stacking path terminating at a stacking position, comprising a carriage with grippers for pulling each flexible sheet from a support and across a shaping member that bends the sheet sufficiently so that the sheet becomes self-supporting as a cantilever member. The carriage takes the sheet to an interleaving position on the stacking path, where one of the articles engages the sheet and carries it to the stacking position. The grippers release the cantilever sheet at about the time the sheet is engaged by the moving article; the carriage then returns for the next sheet. The sheet supply may comprise a hopper with stacked pre-cut sheets, or may constitute a synchronised knife for cutting a sheet from a continuous web just prior to its engagement by the grippers. This machine is specifically designed to be used in conjunction with a forming machine which outputs a pliable patty. US 3, 952, 478 (Richards et al) discloses a sheet applicator for applying individual thin, flexible sheets of paper or similar material to a series of relatively thick, flat articles (e.g., hamburger patties) as those articles fall flatwise along a defined discharge path terminating at a stacking position, comprising a shuttle with vacuum grippers for transferring each flexible sheet from a transfer position to an application position on the article discharge path, where one of the articles engages the sheet and carries it to the end of the discharge path. The grippers engage at least three peripheral points around the edges of the sheet; the falling article pulls the sheet from the gripper, falling through a central opening in the shuttle. The carriage then returns for the next sheet. A single-sheet feeder applies the sheets to the shuttle in registry with the vacuum grippers.

The devices of US '478 and US '387 provide interleaving devices whereby the interleaving is provided by maintaining the paper in a horizontal plane and dropping the hamburger patty onto the paper. The contact between the patty and the paper pulls the sheet from its retainer and effects the formation of a log comprising a plurality of interleaved horizontally stacked patties. This suffers from two disadvantages; firstly there is no positive control of the patty, if frozen, to the point of interleaving and secondly the patties are stacked one on top of the other in contrast to the present invention in which the burgers are transported, on their edges, in horizontal logs.

Object of the Invention

It is an object of the invention to provide a transport apparatus suitable for conveying burgers, on their edges, in individual stacks to an interleaving device or to a packing and/or loading station. It is also an object to provide transport apparatus suitable for conveying the burgers in an unstable format, and in individual logs of predetermined length, or comprising a predetermined fixed number of burgers in the desired orientation, to an interleaving device or to a packing and/or loading station. It is also an object of the invention to provide an improved interleaving device and process for interleaving sheet material between food products such as burgers after the burgers have been individually frozen. It is also an object to provide an interleaving machine which is simple and inexpensive to manufacture and easy to use. It is also an object to overcome many of the disadvantages of known interleaving machines as described above. It is also an object to produce a horizontally-extending log of interleaved burgers, in which the individual burgers are stacked on their edges.

Summary of the Invention

The invention provides a process for interleaving food products, for example burgers, with sheets of sheet material, suitably paper, comprises feeding the food products along a feed path towards a sheet application station, feeding a sheet of sheet material to the sheet application station, and applying a sheet of material to a surface of the food product characterised in that: a) the food products are rigid food products; b) the rigid food products are conveyed in stack formation, on their edges in a substantially horizontal feed path, with the major surface of the food products disposed in a substantially vertical plane, towards the inlet of a sheet application station; c) sheet material is fed to the sheet application station ; and d) at the sheet application station a face of the foremost food product is pressed against a sheet of the sheet material.

At the interleaving station a food product is moved, on its edge, with its major surface disposed in a substantially vertical plane, and the sheet of the sheet material is presented with the plane of the sheet substantially parallel to the plane of the major surface of the food product.

Each food product is conveyed from the inlet of the sheet application station along a substantially vertical path to the sheet application station where it is pushed on its edge, in a substantially horizontal path against the sheet of the sheet material which is held in a substantially vertical orientation. After the sheet of the sheet material has been applied to the face of the foremost food product, the food product and attached sheet are moved in a substantially horizontal path away from the sheet application station.

The sheet of sheet material may carried from sheet supply means, in a substantially vertical orientation to the sheet application station by a sheet carrier mechanism to which the sheet is adhered by suction means. Alternatively, the sheet material is fed from a roll of sheet material.

The invention also provides interleaving apparatus for inserting a sheet material between rigid food products characterised in that it comprises an interleaving station, receiving means at the interleaving station for receiving a rigid food product disposed on its edge with a major surface of the food product disposed on a substantially vertical plane, a sheet delivery system for delivering an interleaving sheet to the interleaving station, with the sheet in a substantially vertical orientation, and means for moving the food product into contact with the sheet. The interleaved food product is produced in horizontally-extending logs of products in which the individual products are stacked substantially upright on their edges.

Preferably the feed path for the rigid food product is substantially horizontal and the feed path for the interleaving sheet is substantially vertical, such that the sheet is presented with the plane of the sheet substantially parallel to the plane of a major face of the food product.

Preferably, a wall of the interleaving station defines a vertically oriented opening, means adjacent the opening for holding an interleaving sheet at the opening with the plane of the sheet in a substantially vertical plane, push means at a receiving surface to push a rigid food product, disposed on its edge on the receiving surface, along a path substantially perpendicular to the plane in which the interleaving sheet is held whereby a major surface of the rigid food product may be pressed into face to face contact with the surface of the interleaving sheet. In accordance with another aspect the invention provides a transport apparatus for transporting stacks of frozen burgers, as hereinbefore defined, to an interleaving device, or to a packing and/or loading station, comprising a substantially horizontal elongate support, adapted to support a stack of rigid food products on their edges and along which the stack may be conveyed, transport means for moving the stack along the channel, and at least one pressure device, moveable from an inactive position, in which the stack may move over it, to an active position in which it presses against the stack to maintain the stack upright.

Brief Description of the Drawings

Figures 1 to 4 are diagrammatic views of one embodiment of transport apparatus of the invention showing the transport of logs of frozen burgers along the apparatus;

Figures 5 to 8 are end elevations of the apparatus of Figures 1 to 4 at various stages in its operation;

Figure 9 is an perspective view from one end of the transport apparatus;

Figure 10 is a perspective view similar to that of Figure 9 showing the transfer of the burgers to vacuum apparatus.

Figure 11 is a diagrammatic sectional side view of part of the transport apparatus of Figures 1 to 4 and also of interleaving apparatus of the invention;

Figure 12 is a diagrammatic sectional side view of a paper sheet delivery system;

Figures 13 and 14 are perspective views of the paper sheet delivery system of Figure

12, at different stages in its operation; and

Figure 15 is a diagrammatic sectional side view showing a modification of the apparatus of Figure 11.

Detailed Description

One embodiment of a transport apparatus for conveying burgers (as hereinbefore defined) to an interleaving device or to a packing and/or loading station is illustrated in Figures 1 to 10. Referring to Figures 1 to 10, transport apparatus for feeding or conveying stacked frozen burgers 1 to an interleaving station or the like comprises and inclined ramp 50, which suitably is inclined at an angle of about 20° to the horizontal. The frozen burgers 1 which have been stacked on their edges by a known stacking machine (not shown) are delivered from the stacking machine along the inclined plane of the ramp 50 to the transport apparatus generally designated as 51.

The transport apparatus comprises a channel consisting of two part-circular elongate supports 52, which, as shown in Figs. 5 to 8, are spaced apart, in parallel arrangement, and are adapted to support the burgers 1, which may be of disc shape, on their edges. The burgers are held upright and slide on their edges along the supports 52, from left to right of Figure 1. Thus, the burgers 1 are conveyed along a substantially non-vertical path, preferably a horizontal path, with the major surface of the burgers in a vertical or substantially vertical plane. It is also envisaged that the path of travel may be inclined to the horizontal, but the burgers are still conveyed on their edges with the major surface of the burgers lying in a vertical plane, a substantially vertical plane, or in a plane substantially perpendicular to the path of travel.

The burgers 1 are preferably presented in the form of a log 2. By "log" is meant a plurality of burgers stacked together, on their edges, with a major face of each burger in contact with the next.

The means for moving the burgers 1 along the supports 52 includes a guide rail 63 which extends above and parallel to the supports 52, in a position midway between the supports. A pair of spaced-apart restraining clamps or lugs 54 and 55, mounted in cylinders 56, are slideably mounted on the rail 63 and slide along the rail 63 in the direction of travel of the burgers 1. The two cylinders 56 are mounted in spaced-apart arrangement at each end of an angular frame 62 which is carried by a sliding bracket 64. As shown in Figures 9 and 10, the bracket 64 engages the guide rail 63 in sliding engagement. The frame 62, carrying the clamps 54, 55, is moved forwardly and backwardly along the guide rail 63 by means of two magnetic tubes 66, 67 which are located below, and parallel with the guide rail 63. The bracket 64, on the frame 62, contains three cylindrical sleeves 65 through which the rail 63 and magnetic tubes 66, 67 pass, so that the bracket may slide along the rail 63 and two tubes 66, 67. Each of the two magnetic tubes 66, 67 contain a moveable permanent magnet (not shown) which moves axially within the tubes by pneumatic means in well known manner. The bracket 64 is also magnetic, of opposite polarity to the magnets within the tubes 66, 67. Thus, movement of the permanent magnets within the tubes 66, 67 causes a parallel movement of the bracket 64, and also the clamps 54, 55 along the guide rail 63. The upper magnetic tube 66 has air pressure applied at the right hand end (as viewed in Figures 9 and 10) and so moves the clamps 54, 55 from right to left; whereas the lower tube 67 is adapted to move the clamps 54, 55 from left to right.

As shown in Figures 9 and 10, the clamps 54, 55 each comprise a pneumatic cylinder 56 which engages the rail 53 in sliding arrangement. The cylinder 56 has a depending piston arm 57 which terminates in a flat paddle 58. As shown in Figures 5 and 6, each arm 7 is retractable, from a position in which the paddle 58 engages the log 2 of burgers 1 , as shown in Figure 5 to a position, as shown in Figure 6, in which it is raised up to disengage from the log 2. The retraction of the arm 57 may be effected, in well known manner, by means of the pneumatic cylinder 56. Alternatively an electromechanical device, such as a solenoid, or hydraulic means may be used to retract the arm 57.

A second guide rail 60, extends below and parallel to the supports 52, in a plane positioned mid- way of the supports 52, and operates in the same manner as the guide rail 63, as described above. It is also provided with two magnetic tubes (not shown) to move a second pair of clamps (lugs) 68 and 69 forwardly and backwardly ofthe rail όO.

The clamps 68, 69 operate similarly to the clamps 54, 55 as described above, and comprise pneumatic cylinders 58, each containing an upwardly extensible piston arm 57, which terminates in a paddle 70. Although in the embodiment described, magnetic tubes are utilised to move the clamps 54, 55 and 68, 69 along the elongate support 52, it will be appreciated that other traction means may be used including mechanical means.

In operation of the apparatus, as shown in Figures 1 to 8, the plurality of frozen burgers 1 are delivered in the form of logs 2 from the discharge unit of a stacker (not shown) along the ramp 50. The frozen burgers slide on their edges on the surface of supports 52. Figure 1 , shows a log A on the ramp 50, whereas a log B has been pushed onto the end of the supports 52. At this point, a sensor activates an automatic feed cycle, and the paddle 58 of clamp 54 engages the end face of the log B and moves the log to the right, as shown in the drawing. The leading burgers in the log B are prevented from toppling forward by the paddle 58 of the forward clamp 55. At this point in the cycle the paddles 58 of the upper clamps 54, 55 are in the extended engaged position, as shown in Figure 5 whereas the paddle 70 of the lower clamp 68 is retracted into the disengaged position as shown in Figure 8, which permits the log B to slide forward over it. In this way, the log B is moved lengthways along the support 52 by the pusher paddle 58 of lug 54; the paddle 58 of lug 55 acting to maintain a light pressure on the leading burger in the log to prevent it from toppling forward. In the meantime, a previous log C has been advanced forwardly of log B until it reaches a gate at the end of the support 52. The log C has been moved forward by the paddle 70 of lug 69. When log B approaches the forward log C, the paddle 70 of lug 69 is retracted to disengage it from the log C, to permit the log B to join the accumulated log C. In the meantime the lug 69 has moved to the left edge of edge log B, and reengages to exert a pressure on the end face of the rearmost burger in the log. Clamp 54 disengages and is moved to the left, followed by clamp 55 to the point where the end of the ramp 50 joins the support 52 where they again engage the forward log B (see Fig. 1), and the accumulation cycle begins again.

The movement of the clamps 54, 55 along rail 63, and of the clamps 68, 69 along rail 30, and the engaging and disengaging of the paddles 58, 70 is controlled, in well known manner, by a programmable logic circuit (PLC). Referring now to Figures 9 to 11 the frozen burgers are moved by the transport apparatus from the ends of support 52 to an in-feed table 6 of feed apparatus 5. In the embodiment shown in Figures 9 and 10 the in-feed table 6 is a continuation of the supports 52, and acts as a discharge chute of the transport feed apparatus.

As described above the frozen burgers are presented on their edges, i.e. with flat surfaces in a vertical plane, and are packed in log format. The accumulated logs, are maintained stable on the in-feed table 6, where they are supported at the front by an optional retaining gate 8 (see Figure 11). Alternatively, or in addition, they are held at the front by engagement of pneumatic clamps 72, which grip the sides of the burgers, as shown in Figure 10. The burgers are pushed forward at the rear by the paddle 70 of clamp 69. As shown in Figure 9, the feed apparatus comprises a plate 75 which contains a circular aperture 73 which is slightly larger in diameter than the burgers 1 so that the burgers can pass through the aperture. The depth of the aperture 73 is approximately equal to the thickness of the burger 1. A suction cup 74 is positioned to the outside of the aperture 73.

The cycle of feeding individual frozen burgers 1 to interleaving apparatus commences (see Figure 9) by moving a plate 15, to which vacuum suction cup 74 is attached into the aperture 73 of the end plate 75. The clamps 72 (see Figures 9 and 10), then open to allow the accumulated log to advance so that the leading burger comes to bear on the face of the vacuum cup 74. The clamps 72 then close and grip the next burger in the log. Air is exhausted from the vacuum cup through a vacuum hose 76 (see Figure 9). Plate 15 having the suction cup 74 moves to the right carrying the leading burger la with it. The vacuum cup 74 is controlled by a make and break circuit. Thus, as the plate 15 moves to a retaining plate 18, the circuit is broken, the vacuum is released and the leading burger la falls by gravity, in a substantially vertical path, through a vertical chute 12 defined by vertically disposed plates 17, 18 which are spaced apart.

The falling burger comes to rest on a horizontal receiving plate 10 of an interleaving apparatus 9. The interleaving apparatus comprises the receiving plate 10 which receives the burger la, to be interleaved, disposed vertically on the plate 10. The plate 10 has an aperture or slot 29 through which a paper sheet 30 is fed by an interleave sheet delivery system, as described below. The single paper sheet 30 is held over an opening 19 in the plate 18. A sliding plate (or pusher) 21, mounted above the receiving plate 10 is advanced horizontally towards the opening 19 and presses the burger la, held on the plate 10, against the sheet 30 to cause the sheet 30 to abut the front face of the burger la. The burger la with sheet 30 attached to the front face is pushed onto a substantially horizontal support 12, e.g. a plate which is substantially in the same plane as the receiving plate 10. Alternatively, the support 12 may comprise a plurality of inclined rods. The sliding plate 21 pushes the burger la with interleaved sheet 30 attached against the rear face of a preceding interleaved burger lb of an accumulated log 22 of previously interleaved burgers. The log 22 is held in a stable position by a vertical retaining plate 25, which is pressed against the front of the log 22, for example by a pneumatically operated ram (not shown). From the support 12 the interleaved logs 22 of burgers are fed to a packing station (not shown).

One embodiment of a sheet delivery system 17 is shown diagramatically in Figure 12, and in perspective view in Figures 13 and 14. Referring to these drawings, the interleaving paper delivery system comprises a magazine 16 which holds a quantity of pre-cut interleaving sheets 30 (Fig. 12.1). The sheets 30 are held in position against a sheet carrier mechanism 26. The sheet delivery system 17 is shown in more detail in Figures 13 and 14 and is described more fully below. The sheet carrier mechanism 26 is free to slide vertically, upwardly and downwardly through aperture 29, for example by means of a pneumatic ram.

The sheet carrier mechanism 26 includes a vacuum-operated suction device by means of which the leading sheet 30 of paper in the magazine 16 adheres to the face of the carrier mechanism 26 when vacuum is applied. The carrier mechanism 26 is then moved vertically upwardly, by means of a pneumatic ram, through the aperture 29 (see Figure 12.2) where it is aligned with the opening 19 in the plate 18. The plate 18 has a recess 31 adjacent the opening 19 to receive the sheet carrier mechanism 26. Vacuum ports 32, 33 (of which there may be four in number) are provided around the perimeter of opening 19 and when the carried sheet 30 is positioned facing the opening 19, the carrier mechanism 26 is disconnected from the vacuum source to free the sheet 30, and simultaneously vacuum is applied to the ports 32, 33 such that the sheet 19 is attached to the flange 35. The sheet carrier mechanism 26 is then retracted back down through aperture 29 as shown in Figure 12.3.

The slide plate 15 then comes into operation, as described above, to move the burger la, held on receiving plate 10, into contact with the paper sheet 30 held at the opening 19. At that stage, the ports 32, 33 are disconnected from the vacuum source to allow the burger la with attached paper sheet 30 to move horizontally into contact with the log 22 as described above. The cycle then recommences.

An interleaved paper delivery apparatus, of known construction, is shown in Figures 13 and 14. It comprises a support frame 40 which is mounted below the receiving plate 10. The support frame 40 has vertical guides 41 within which a sheet carrier plate 26 is adapted to slide vertically. The sheet carrier plate 26 is moved vertically by means of a pneumatic ram 42. A sheet support, in this case a rod 43, projects forwardly from the support frame 40. The sheet support rod 43 is adapted to support a magazine of pre-cut interleaving paper sheets 30. The face 44 of the sheet carrier plate 26 contains vacuum ports 45. An O-Ring is recessed in each vacuum port to assist the seal between the vacuum ports and the sheet 30. Air is evacuated from the vacuum ports 45 through nipples 46 which are connected to suitable air lines (not shown). Suitably, the face 44 is coated with a non-stick coating such as Teflon®. The carrier plate 26 is moveable from the position shown in Figure 13 to an upper position as shown in Figure 14 to withdraw a sheet from the sheet magazine held on rod 43, through the aperture 29 as described above, to deposit the sheet 30 at the interleaving station.

An alternative paper feed system is now described with reference to Figure 15.

The construction and operation of the interleaving station is the same as that described above with reference to Figure 11 but the method of delivering the paper sheets 30 to the interleaving station is different. In this embodiment a feed roll 80 of grease-proof paper or the like, is positioned below the support 12. A web or strip of paper 81 is fed from roll 80 through a pair of opposed feed rollers 82. The feed rollers 82 are positioned immediately below the aperture 29 and are adapted to deliver the web of paper upwardly in a vertical orientation, through the aperture 29, into position at the opening 19, as shown in the drawing. When the paper is in this position a slitter 83 operates to detach the sheet 30 of paper from the web 81. Otherwise, interleaving apparatus and process operates as described above.

Thus the process and apparatus of the invention conveys flat surfaced rigid bodies, such as burgers, while their major surface is in the vertical plane. It provides buffer means to smooth the effect of arrival variations of the burgers at the end of the initial transport phase, so as to provide a stable accumulation of the burgers with their major surfaces parallel to each other. It forms a log of the burgers in the horizontal plane and each is presented in a format suitable for further processes e.g. interleaving. An interleaving sheet is automatically dispensed from a magazine of pre-cut sheets or from a roll of sheet material. The sheets are dispensed and each sheet d is presented on its edge (major surface in vertical plane) and it is held in the path of the burger being interleaved. The burgers are pushed horizontally (perpendicular to the movement of the interleaving sheet) thus bringing them face to face and forcing the interleave sheet forward horizontally away for its presentation point to an accumulating station. It will be appreciated that in the illustrated embodiments the movement of the interleaving sheet has been described as a movement in a vertical orientation but that it is not intended to limit the present invention to any such specific movement. Those skilled in the art will appreciate that individual sheets or rolls can be transferred from a storage location to the point of interleaving with the rigid article from any direction or plane of travel. Once the sheet is presented at the interleaving position its major surface should be in a vertical plane, how it travelled to this position may vary.

The process executes the controlled detachment of individual burgers from the accumulated log at high speed (up to and above 100 per minute). The burgers are maintained the same orientation (major surface in the vertical plane) throughout the process. They are transferred individually to the interleaving station. The process introduces them face to face in the vertical plane with interleaving material, it transfers the burger so that it pushes the interleaving sheet a short distance to an accumulating station, thus forming a log of individually interleaved burgers.

The process automatically interleaves burgers of substantially flat surfaces and of a variety of shapes, and accommodates wide dimension tolerances.. For example, it can handle burgers of varying/inconsistent shapes, surface roughness, thickness etc., and while the major surface of each is in the vertical plane i.e. inertia unstable, and it presents the accumulated burgers in a stable horizontal log of interleaved burgers in a format suitable for automatic handling e.g. automatic packaging.

The process produces a log of interleaved objects in a controlled format thereby facilitating automation of subsequent operations.

It will be appreciated that the interleaving device of the present device provides for positive control and movement of the objects or articles requiring interleaving. This is advantageous for many reasons including the fact that it facilitates the interleaving of rigid articles from a variety of processing steps including but not limited to freezing, slicing etc.. Using an active or positive control of the movement of each of the articles enables the separation of individual articles from a log, the transportation of the articles to the point of interleaving and a subsequent re-formation of a log having a plurality of interleaved articles. It will also be appreciated that in the preferred embodiment of the present invention the re-formed log is orientated in a horizontal plane, i.e. the plane of the major surface of each of the individual articles is maintained in a vertical orientation which facilitates the downstream processing of such stacked logs in packaging or other such processes.

From the foregoing, it will be apparent that numerous modifications and variation can be effected without departing from the true spirit and scope of the novel concept of the present invention. It will be appreciated that the present disclosure is intended to set forth the exemplifications of the invention which are not intended to limit the invention to the specific embodiments illustrated. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.

Where technical features mentioned in any claim are followed by reference signs, these reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components and groups thereof.

Claims

1. A process for interleaving food products, for example burgers (1), with sheets (30) of sheet material, suitably paper, comprises feeding the food products (1) along a feed path towards a sheet application station, feeding a sheet (30) of sheet material to the sheet application station, and applying a sheet (30) of material to a surface of the food product (1) characterised in that: a) the food products are rigid food products; b) the rigid food products (1) are conveyed in stack formation, on their edges in a substantially horizontal feed path, with the major surface of the food products disposed in a substantially vertical plane, towards the inlet of a sheet application station; c) sheet material (30) is fed to the sheet application station; and d) at the sheet application station a face of the foremost food product (la) is pressed against a sheet (30) of the sheet material.

2. A process as claimed in Claim 1, characterised in that at the interleaving station a food product (la) is moved, on its edge, with its major surface disposed in a substantially vertical plane, and the sheet (30) of the sheet material is presented with the plane of the sheet substantially parallel to the plane of the major surface of the food product (la).

3. A process as claimed in Claim 1 or Claim 2, characterised in that each food product (1) is conveyed from the inlet of the sheet application station along a substantially vertical path to the sheet application station where it is pushed on its edge, in a substantially horizontal path against the sheet (30) of the sheet material which is held in a substantially vertical orientation.

4. A process as claimed in any of Claims 1 to 3, characterised in that after the sheet (30) of the sheet material has been applied to the face of the foremost food product (la), the food product (la) and attached sheet (30) are moved in a substantially horizontal path away from the sheet application station.

5. A process as claimed in any of the preceding claims characterised in that the sheet (30) of sheet material is carried from sheet supply means (16), in a substantially vertical path to the sheet application station by a sheet carrier mechanism (26) to which the sheet is adhered by suction means.

6. A process as claimed in any of Claims 1 to 5, characterised in that the sheet (30) of sheet material is fed from a roll of sheet material.

7. Interleaving apparatus for inserting a sheet material between rigid food products characterised in that it comprises an interleaving station, receiving means (10) at the interleaving station (9) for receiving a rigid food product (la) disposed on its edge with a major surface of the food product (la) disposed in a substantially vertical plane, a sheet delivery system (26) for delivering an interleaving sheet (30) to the interleaving station (9), with the sheet (30) being in a substantially vertical orientation at the interleaving station, and means (21) for moving the food product (la) into contact with the sheet.

8. Interleaving apparatus as claimed in Claim 7, characterised in that a wall (18) of the interleaving station (9) defines a vertically oriented opening (19), means (32,33) adjacent the opening 19 for holding an interleaving sheet (30) at the opening with the plane of the sheet (30) in a substantially vertical plane, push means (21) at a receiving surface (10) to push a rigid food product (la), disposed on its edge on the receiving surface (10), along a path substantially perpendicular to the plane in which the interleaving sheet (30) is held whereby a major surface of the rigid food product (la) may be pressed into face to face contact with the surface of the interleaving sheet (30).

9. Interleaving apparatus as claimed in Claim 8, characterised in that the receiving surface (10) is positioned at one side of the opening (19), and a accumulating station (12) is positioned at the opposite side of the opening (19), means (32, 33) are provided at the opening for holding an interleaving sheet (30) over the opening (19), and push means (21) are provided to move a rigid food product (la), on its edge, against the sheet (30), and to move the rigid food product (la) with sheet (30) attached through the opening (19) to deposit the rigid food product (la) at the accumulating station (12).

10. Interleaving apparatus as claimed in any of Claims 7 to 9, characterised in that it includes a transport apparatus for transporting stacks of rigid food products (1) to an interleaving station comprising a substantially horizontal elongate channel (52), adapted to support a stack (2) of rigid food products (1) on their edges and along which the stack may be conveyed, transport means for moving the stack along the channel (52), and at least one pressure device (54, 55, 68, 69), moveable from an inactive position, in which the stack may move over, or under, it, to an active position in which it presses against the stack to maintain the stack upright.

11. Interleaving apparatus as claimed in Claim 10, characterised in that the transport means comprises at least one clamp (54), moveable horizontally relative to the channel (52), and adapted to move the stack (2) along the channel (52).

12. Interleaving apparatus as claimed in Claims 10 or 11, characterised in that there are at least two pressure devices (55, 68) and two transport means (54, 69).

13. Interleaving apparatus as claimed in any of Claims 10 to 12, characterised in that the transport apparatus comprises two spaced-apart elongate supports (52), and which are adapted to support rigid food products (1) on their edges, at least one pair of spaced-apart clamps (54, 55) is mounted, above the supports (52) and are moveable along the supports (52), and are each adapted to engage a front and rear leading face of a stack (2) of food products (1) so as to convey the stack (2) along the supports (52) and to maintain the stack (2) with the major surface of the food products (1) in a vertical or substantially vertical plane as the stack (2) is conveyed.

14. Interleaving apparatus as claimed in any of Claims 10 to 13, characterised in that retaining gate means (8) are provided at the end of the channel (52) at which a stack (2) of the rigid food products (1) may be held by holding means (8, 72), means (74) for transporting individual rigid food products (1) from the gate means (8) to an interleaving station (9).

15. Interleaving apparatus as claimed in Claim 14, characterised in that a substantially vertical chute (12) extends between the gate means (8) and the interleaving station (9), the transport means (74) is adapted to move individual rigid food products (1) from the gate means (8) and to release the rigid food products into the chute (1 1).

16. Interleaving apparatus as claimed in either of Claims 14 or 15, characterised in that the transport means comprises a vacuum operated suction cup (74) adapted to grip an individual rigid food product (1) at the gate means (8) and means are provided to move the suction cup (74) in a substantially horizontal path, and means at the end of the path to release the vacuum such that the rigid food product (1) falls into the chute (11).

17. Interleaving apparatus as claimed in any of Claims 7 to 16, characterised in that the sheet delivery system comprises a magazine (16) for holding a supply of interleaving sheets (30), a carrier mechanism (26) having suction means (45) whereby an interleaving sheet may be attached to the carrier mechanism (26), means (42) for moving the carrier mechanism from the magazine (16) to the interleaving station (9) with the sheet (30) held in a substantially vertical orientation.

18. Interleaving apparatus as claimed in Claim 17, characterised in that the carrier mechanism (26) moves vertically upwardly from the magazine (16) to align with the opening 19, means for releasing the suction of the suction means (45) to release the sheet (30) from the carrier mechanism (26), and suction means (32, 33) adjacent the opening (19) to hold the sheet (30) in a substantially vertical orientation at the interleaving station (10).

19. Interleaving apparatus as claimed in any of Claims 7 to 16, characterised in that it comprises a paper feed roll (80), means (82) for feeding a web or strip (81) of paper from the feed roll (80) to the interleaving station (9), along a substantially vertical path, means (83) at the interleaving station (9) for detaching an interleaving sheet (30) from the web or strip (81).

20. A process as claimed in any of claims 1 to 6, characterised in that the rigid food products (1) are conveyed in a log (C), on their edges, on transport means (51), to gate means (8), and at the gate means (8) individual rigid food products (1) are positively detached from the log (C) and delivered individually to an interleaving station.