GB2041331A

GB2041331A - Packaging Compressed Materials

Info

Publication number: GB2041331A
Application number: GB8002186A
Authority: GB
Original assignee: WINCANTON ENG Ltd; Wincanton Engineering Ltd
Current assignee: WINCANTON ENG Ltd; Wincanton Engineering Ltd
Priority date: 1979-02-09
Filing date: 1980-01-23
Publication date: 1980-09-10
Also published as: GB2041331B

Abstract

A container for packaging a wrapped block 12 of cheese or other soft product and maintaining pre-set length and breadth dimensions of the block 12 despite shrinkage comprises four rigid side panels 13-16 and two rigid end covers 10, 17 each end cover 10, 17 having a peripheral flange 20, 22 which retains the side panels 13, 16 at pre-set distances from one another when subjected to internal pressure by engagement with the block 12. Upon assembly, each end cover 10, 17 is forced inwards towards the other to compress the wrapped block 12 against the side panels 13-16 held by the flanges 20, 22. While under compression, the container is bound with strapping under tension extending across the end covers. Each end cover 10, 17 has surface serrations 32, 36 to prevent relative movement of stacked containers. <IMAGE>

Description

SPECIFICATION Improvements in the Packaging of a Block of Cheese or other Soft Product, and Containers Therefor This invention relates to the packaging of a block of natural cheese, butter or other soft product, and is particularly applicable to the packaging, preparatory to maturing, of blocks of natural cheese produced by compressing cheese curd to consolidate the particles of curd.

In the commercial manufacture of hard cheese, the cheese curd is compressed in a mould into a rectangular block of natural cheese having a fixed length and breadth determined by the transverse dimensions of the mould, but a depth which is dependent on the mass and density of the cheese and width may vary by up to half an inch.It has hitherto been common practice to enclose the cheese block in a sealed bag of plastics film which is impervious to air and moisture, the bag being evacuated of air and heat-shrunk to remove wrinkles, and the wrapped block packaged in rigid panels which are brought together and then bound by steel tape to form a rigid-walled container, the faces of two opposing side panels abutting against edges of the other two side panels, and the top and bottom panels being a close fit against the faces of the side panels to define a chamber having fixed length and breadth dimensions equal to those of the moulded block of cheese. The top and bottom panels are movable towards one another to accommodate variation in the depth of block in the chamber.

This method of packaging a cheese block is described and illustrated in British Patent Specification No. 937,411.

The cheese pack is transported to a maturing station where it is stacked and kept for the appropriate time under the required maturing conditions. The pressure applied through the panels to the cheese block by the steel tape ensures that the panels are held firmly in contact with one another and against all faces of the wrapped cheese block, despite small shrinkage which occurs in storage, to maintain the cheese block in a rectangular shape with fixed length and breadth dimensions. It is essential that the length and breadth dimensions of the block be maintained since otherwise, when the cheese is matured, wastage would occur when subdividing the block into consumer portions of regular weights by machinery to handle such blocks.

The packaging method described above is however labour intensive and requires considerable manual dexterity on the part of the operators. Natural cheese, prior to maturing, is very malleable and the tension in the heat-shrunk plastics wrapping distorts the block out of its rectangular shape by rounding off the edges and corners of the block. It is then difficult to assemble six panels around a block of cheese which has been distorted out of a rectangular shape, press the panels against the wrapped block to bring it back into a rectangular shape of fixed length and breadth dimensions, and then hold all the panels pressed flat against the sides of the block with adjacent panels perpendicular to one another while the panels are being bound by steel tape. Also considerable quantities of steel binding tape are used in large scale commercial production of the cheese.

The object of the invention is to provide an improved method of packaging a block of a soft product which will maintain fixed transverse dimensions of the block, and which is easier and quicker than the packaging method described above.

According to the present invention there is provided a method of packaging a block of a soft product such as natural cheese, which comprises wrapping the block completely in flexible film-like material which is substantially impervious to air and moisture, fitting rigid side panels flat against the sides of the wrapped block and rigid end covers flat against the top and bottom of the wrapped block, the side panels projecting above and below the wrapped block and the end covers having slots for reception of the top and bottom edges of the side panels, the side panels and end covers co-operating to form a container which encloses the wrapped block with clearance being provided between the upper and lower ends of the side panels and the bases of the slots in the end covers to permit inward movement of each of said end covers towards the centre of the container, and the outer walls of said slots preventing outward movement of the side panels beyond predetermined limits due to internal pressure, and then applying force to the end covers so as to compress the product into a block having fixed transverse dimensions determined by the spacing between the side panels located in said slots.

The end covers of the container are preferably bound together by metal or nylon strapping extending around the container and across the end covers, while the product is under compression. It is not necessary to strap the side panels since these are held in position by the outer walls of the slots in the end covers. Such a pack uses less strapping than that of the known method of packaging described above in which the strapping extends around the sides as well as around the ends of the pack.The overall dimensions of the wrapped block in planes normal to the side panels are pre-set by the distances between the outer walls of the slots which locate opposing side panels in position, and these dimensions of the wrapped block remain constant even although the product shrinks in storage since the tension in the strapping and atmosphere pressure continually compresses the product against the side panels.

It is an essential feature of the invention that sufficient clearance be provided between the upper and lower ends of the side panels and the bases of the slots in the end covers to enable each end cover to move inwards towards the centre of the container during compression of the product.

The reason for this is that, when the product is subjected to compression, the frictional force between the film wrapping on the product and the side panels restricts sliding movement of the film on the side panels. A block of a soft product vacuum wrapped in film normally has radiused corners, and if the container is wrongly assembled around the block without clearance between the side panels and the bottom cover, the internal pressure of the product would impose great stress on any film which was not in direct contact with the internal surfaces of the container. The film would either rupture or prevent the product from fully conforming to the inside of the container, thus leaving the radiused corners and edges all round the bottom. Rupture of the film results in loss of vacuum and, in the case of cheese, growth of mould in surrounding areas.

In the method of the invention, the side panels and bottom cover can be assembled around the wrapped product before the top cover is put on, thereby allowing greater conformity to the bottom of the container before any pressure is applied.

When the end covers are pressed together, the product flows mainly laterally outwards due to the fact that each end cover is movable inwardly. As the height of the product decreases with its outward displacement, each end cover follows the movement so that the product is able to move into the corners as the containing film or bag merely changes shape regardless of any friction on the side panels and with little strain from internal pressure.

This self adjusting equalizing action enables blocks of cheese to be matured whilst retaining extremely accurate shape with sharp corners and edges. Moreover, the fact that a great deal of the conforming movement takes place during assembly of the pack results in a very stable unit which can safely be stacked to considerable height.

Cheese blocks packaged in containers in accordance with the invention are preferably stacked one on another during maturing of the cheese. To facilitate stacking of the containers, each of the end covers preferably has an outer surface formed with a first set of serrations and a second set of serrations arranged perpendicular to said first set of serrations; the two sets of serrations on each end cover being adapted to interlock with the corresponding serrations on an end cover of another container of the same construction, when the two containers are mounted one on another, to prevent relative transverse movement in any horizontal direction between the two containers, the serrations of said one set being spaced from the serrations of said second set to enable the serrations to interlock when the containers are offset a short distance relative to one another.

The wrapped block of cheese may, if desired, be enclosed in a thin cardboard carton and the rigid panels applied against the walls of the carton to form a rigid-walled container in accordance with the invention. The construction of the carton is such that it can accommodate intself to the assembly of panels without trapping the innermost film when pressure is applied to the panels.

Several cheese blocks may if desired by packaged in a single rigid-walled container in accordance with the invention and the term block as used herein includes two or more individual blocks assembled together into a stack.

A method of packaging a rectangular parallelepiped block of natural cheese to form a cheese pack with a rigid-walled outer container in accordance with the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is an exploded view of the container and the cheese block, Figure 2 is a perspective view of the container assembled around the cheese block to form a cheese pack, Figure 3 is a cross-sectional view of the cheese pack of Figure 2 taken along the line Ill-Ill, Figure 4 is a detail view of part of the container taken along the line lV-IV of Figure 1, Figures 5-8 are diagrammatic views illustrating one method of packaging the cheese block in the container, and Figure 9 is a perspective view of a modified construction of the container.

The cheese block to be packaged is first enclosed in a bag of limp flexible laminated plastics film material which is heat-sealable, heatshrinkable and impervious to air and moisture, the bag then being sealed, evacuated of air, and shrunk to remove wrinkles.

The container comprises a bottom cover 10 shaped to provide a rectangular bottom panel 11 engageable flat against the bottom of the wrapped block identified by the numeral 12, four side panels 13, 14, 1 5, 1 6 engageable flat against the four sides respectively of the wrapped block, and a top cover 17 shaped to provide a rectangular top panel 18 engageable flat against the top of the wrapped block. The bottom cover 10 has a peripheral flange 20 which projects above the top surface of the panel 11 and cooperates with the periphery of panel 11 to form a channel shaped slot 21. Similarly the top cover 1 7 has a peripheral flange 22 which projects below the bottom surface of panel 1 8 and cooperates with the periphery of panel 1 8 to form a channel shaped slot 23.

The top and bottom covers 10, 1 7 are identical in construction and as shown in the drawings, each comprises a relatively thin wall which is shaped to form the associated panel 11 or 18, the slot 21 or 23 surrounding the panel, and the flange 21 or 22 forming the outer wall of the slot.

Two longitudinal ribs 25, 26 and three transverse ribs 27, 28, 29 extend across the recessed outer face of the panel to provide reinforcement. The longitudinal ribs 25, 26 and the longitudinal sides 30, 31 of each end cover are formed with transverse serrations 32, and the centre transverse rib 28 and the transverse sides 34, 35 are formed with longitudinal serrations 36, for a purpose explained hereinafter. The serrations project outwards beyond the surfaces of the ribs 27, 29 and the surfaces of the intersections of the ribs 25-29 and sides 30, 31,34. 35, which intersections are free of serrations.

The top and bottom covers and the side panels are made of a substantially rigid material and can conveniently be moulded in rigid plastics material.

The bottom panel 11 and the top panel 18 have a length and breadth equal to the length and breadth of the wrapped block, and the slots 21, 23 are of a size such that the edges of the side panels are a close sliding fit therein. The opposing side panels 13, 1 5 have a length equal to the breadth of the wrapped block, the opposing side panels 14, 1 6 have a length equal to the aggregate of the length of the wrapped block and the thickness of the side panels 13, 1 5, and all the side panels are of the same height which is approximately equal to the aggregate of the depth of the wrapped block and the depth of one of the slots 21,23.Thus in the assembled container the inside surfaces of the side panels 14, 1 6 face the ends of the side panels 13, 1 5, and the top and bottom panels 11, 1 8 engage as a close sliding fit against the inside surfaces of the side panels 13, 14, 1 5, 16. The flanges 20, 22 on the end covers encircle the side panels and maintain the spacing between the side panels to preset limits determined by the dimensions of the flanges when the side panels are forced outwards by internal pressure.

The panels are assembled around a wrapped block of cheese with the aid of a power operated press (not shown) and a plate 40 having a length and breadth less than that of the cheese block and a thickness equal to half the depth of the slot 21 or23.

The plate 40 is placed on a flat surface 41 and the wrapped block placed centrally on the plate as shown in Figure 5. The side panels 13-16 are then placed vertically on the surface 41 and engaged flat against each of the sides of the wrapped block as shown in Figure 6. The bottom cover 10 is then mounted upside down on the top of the block with the upper edges of the side panels engaged in the slots 21 in the bottom cover. The power operated press may be used to compress the cheese block between the side panels if it has become distorted out of its rectangular shape to an extent presenting engagement of the upper edges of the side panels in the slots 21. The assembly of the wrapped block, the bottom cover and the side panels is then lifted off the plate 40 and turned over so that the bottom cover rests on the flat surface as shown in Figure 7.At this stage the side panels are gripped sufficiently firmly between the cheese block and the flange on the bottom cover to enable a single operator to handle the assembly as a unit without altering the positions of the side panels relative to the bottom cover and the block.

The top cover 1 7 is then mounted in position with the flange 22 encircling the side panels and the top panel 1 8 engaged flat against the top of the wrapped block as shown in Figure 8. The power operated press may again be used to compress the cheese block between the side panels if this should be necessary to engage the side panels within the flange 22. The container is then fully assembled with the side panels 1 3, 1 5 disposed between the side panels 14, 1 6, and the end panels 11, 1 8 disposed between the side panels 13, 14, 15, 16. The side panels are engaged in the slots 21,23 in the end covers but are spaced from the bottom of the slots as shown in Figure 3 to permit inward movement of the end covers.

The cheese block is then compressed inside the container by forcing the end covers 10, 1 8 towards one another by the power operated press, so that the edges of the side panels slide further into the slots 21,23 in the end covers.

This compression of the block forces the cheese to flow into the corners of the rectangular space enclosed by the panels. The pressure of the cheese exerts an outward force on the side panels, but these panels are held by the encircling flanges 20, 22 on the end covers, so that the cheese block is maintained in a rectangular shape with fixed length and breadth dimensions dete'rmined by the internal dimensions of the flanges 20, 22. While the cheese block is under compression by force exerted on the end covers, the cheese pack is bound by metal or nylon straps 45 extending around the top and bottom end covers.

The straps 45 are arranged so that they lie along the transverse ribs 27, 29 and between the serrations on each side of the ribs 27, 29, the serrations projecting outwards beyond the outside surfaces of the straps. When the cheese pack is released from the press, the tension in the straps 45 holds the top and bottom panels pressed against the top and bottom of the wrapped cheese block. The upper and lower edges of the side panels are however still spaced from the bottoms of the slots 21, 23 to permit inward movement of the end panels under the tension exerted by the straps 45 upon shrinkage of the cheese block during storage. Due to the fact that the flanges on the end covers completely locate and retain the side panels, most of the compressive force applied by the straps 45 is available to cause the end panels to follow up any shrinkage of the block and maintain the cheese under compression.

The method of assembling the container around the wrapped cheese block as described above in which the side panels are applied to the block before fitting the end covers has the advantage that the whole pack can be put together with very little risk of straining or rupturing the protective film around the cheese.

Moreover, the ability of the end covers to move inwardly relative to the side panels minimises drag on the film during assembly and compression of the cheese block and greatly reduces strain on the corners and edges of the block.

The block of cheese may be wrapped in a sheet of plastics film material, having overlapping portions, instead of being enclosed in a preformed bag. Air is evacuated from between the wrapping and the block of cheese before pressure is applied to the panels, this pressure being relied upon to seal the overlapping portions of the film and prevent ingress of air during storage of the cheese pack.

The method of the invention can bs used to package several blocks of natural cheese in a single rigid-walled container for storage of the cheese at a maturing station. In this method, a bottom cover 10 having an end panel 11 of appropriate dimensions is placed on a platform.

The base of the slots 21 in the bottom cover is fitted with retractable pins which extend vertically upwards a distance equal to approximately half the depth of the slots. A sheet of laminated plastics material is placed across the panel 11, the several blocks of cheese mounted on the sheet on the bottom panel in a rectangular parallelepiped stack of the appropriate dimensions, and the edges of the sheet wrapped around the stack with overlapping portions at the ends. Side panels are then fitted in the slots in the bottom cover, the side panels being supported by the pins, and a top cover fitted on the stack of cheese blocks with the upper edges of the side panels engaged in the slot in the top cover. The pins in the bottom cover are then retracted and the two end covers pressed together and bound by strapping as described above.

A number of the containers may be stacked one on another for storage during maturing of the cheese. The transverse and longitudinal serrations 32, 34 in the top cover of each container interlock with the corresponding transverse and longitudinal serrations on the bottom cover of a superimposed container and thereby prevent relative horizontal movement between the two containers in any direction. It is not neccessary for the containers to be accurately aligned with one another in the stack, since the spacing between the strips of serrations enable the serrations to interlock even when the containers are offset from one another a distance corresponding to the pitch of one or more of the serrations in the longitudinal or transverse direction of the containers.

In the modified construction shown in Figure 9, the serrations are in the form of rectangular section splines or teeth which extend along the length of the sides 30, 31 , 34, 35, the splines being arranged in groups with the splines of each group aligned with the gaps between the splines of the adjacent group or groups, and also being arranged so that splines on adjacent end covers of superimposed end covers intermesh when the two containers are in vertical alignment. The splines can conveniently be 2 mm in height, and the ribs 25, 26, 28 formed with a plain surface 1 mm above the level of the top surfaces of the sides, except for the portions transversed by the straps 45. Thus the adjacent end covers on two containers mounted one on the other will have the splines on each end cover abutting the surfaces between the splines on the adjacent end cover, and the ribs on each end cover other than those covered by the straps abutting the corresponding ribs on the other end cover, so as to provide a substantially even distribution of load on the end covers.

Although the invention has been described particularly with reference to the packaging of cheese for maturing, the method of the invention and the container illustrated in the drawings can be used for the packaging of any other soft product, for example butter.

Claims

1. A method of packaging a block of a soft product such as natural cheese, which comprises wrapping the block completely in flexible film-like material which is substantially impervious to air and moisture, fitting rigid side panels flat against the sides of the wrapped block and rigid end covers flat against the top and bottom of the wrapped block, the side panels projecting above and below the wrapped block and the end covers having slots for reception of the top and bottom edges of the side panels, the side panels and end covers co-operating to form a container which encloses the wrapped block with clearance being provided between the upper and lower ends of the side panels and the bases of the slots in the end covers to permit inward movement of each of said end covers towards the centre of the container, and the outer walls of said slots preventing outward movement of the side panels beyond predetermined limits due to internal pressure, and then applying force to the end covers so as to compress the product into a block having fixed transverse dimensions determined by the spacing between the side panels iocated in said slots.

2. A method as claimed in claim 1, including the step of compressing the wrapped block between the side panels prior to fitting the end covers to the wrapped block with the edges of the panels engaged in the slots.

3. A method as claimed in claim 1, including the step of binding the end covers together while the block is compressed between the panels

4. A method as claimed in claim 3, wherein the end covers are bound together by fitting strapping under tension around the container and across the end covers.

5. A method of packaging a rectangular block of a soft product according to the method of claim 1, including the step of compressing the wrapped block between said side panels with the surfaces of two opposing side panels abutting against the edges of the other two side panels before fitting the end covers to the wrapped block with the edges of the panels engaged in the slots.

6. A method of packaging a rectangular block of natural cheese preparatory to the maturing thereof, which comprises wrapping the cheese block completely in flexible film-like material which is substantially impervious to air and moisture, evacuating air from between the wrapping and the block of cheese, compressing the wrapped block between rigid side panels engaged flat against the sides of the wrapped block and projecting above and below the top and bottom of the wrapped block, fitting end covers flat against the top and bottom of the wrapped block, each end cover comprising a rigid end panel having a length and breadth corresponding to the length and breadth of the block to be packaged and a peripheral flange co-operating with the edges of the end panel to form slots for the reception of the top and bottom edges of the side panels, and the side panels and end covers co-operating to form a container which encloses the wrapped block with clearance being provided between the upper and lower ends of the side panels and the base of the slots in the end covers when the end panels are engaged flat against the block to permit inwards movement of each of said end covers towards one another upon compression of the cheese, the flanges on the end covers preventing outward movement of the side panels beyond predetermined limits due to internal pressure, subsequently compressing the wrapped block between the end covers so as to provide the block with fixed length and breadth dimensions determined by the spacing between the side panels, and then binding the container by strapping under tension extending across the end covers while the block is compressed between the end covers.

7. A container packaging a block of a soft product wrapped in film material, the container comprising rigid side panels engaged flat against the sides of the wrapped block and two end covers engaged flat against the ends of the wrapped block, the side panels projecting beyond the ends of the wrapped block and the end covers having slots which receive the end edges of the side panels as a close sliding fit so that the panels and end covers co-operate to define a chamber accommodating the wrapped block and the outer walls of said slots prevent outward movement of the side panels beyond predetermined limits due to internal pressure, the ends of said side panels being spaced from the bottom of the slots in each end cover to permit movement of each end cover towards the other end cover, and means applying pressure to the end covers and thereby compressing the product into a block having fixed transverse dimensions determined by the spacing between the side panels.

8. A container as claimed in claim 7, wherein strapping under tension extends around the container and across the end covers so as to hold the covers against the wrapped block and maintain the wrapped block in compression.

9. A container packaging a rectangular block of natural cheese wrapped in film material, the container comprising four rigid side panels engaged flat against the sides of the wrapped block and projecting above and below the top and bottom of the block, and two end covers each comprising a rigid end panel having a length and breadth corresponding to the length and breadth of the wrapped block and a peripheral flange cooperating with the edges of the panel to form slots, the end panels being engaged flat against the top and bottom of the wrapped block and the top and bottom edges of the side panels extending into said slots so that the side panels and end covers co-operate to define a chamber accommodating the wrapped block clearance being provided between the upper and lower ends of the side panels and the base of the slots in the end covers, and strap means under tension which encircle the container and extend across the end covers so as to force the end covers inwardly and compress the cheese into a block having fixed length and breadth dimensions determined by the peripheral dimensions of the flanges holding the side panels in position.

10. A container as claimed in claim 9, wherein two of said side panels on opposite sides of the block are disposed between the other two side panels.

11. A container for packaging a rectangular block of a soft product wrapped in film material, the container comprising four rigid side panels and two end covers adapted to be fitted on the ends of the side panels when engaged against the sides of a wrapped block, each end cover comprising an end panel and a peripheral flange co-operating with the end panels to form a slot for reception of the adjacent ends of the side panels in the assembled container, the flange projecting beyond the inside face of the end panel.

12. A container as claimed in claim 11, wherein the edges of two opposing side panels in the assembled container are contiguous to the adjacent faces of the other two opposing side panels, and the end panels are a close sliding fit between the side panels.

13. A container as claimed in claim 11, wherein each of said end covers has an outer surface formed with a first set of serrations or splines and a second set of serrations or splines arranged perpendicular to said first set of serrations or splines, the two sets of serrations or splines on each end cover being adapted to interlock with the corresponding serrations or splines on an end cover of another container of the same construction, when the two containers are mounted one on another, to prevent relative transverse movement in any horizontal direction between the two containers, the serrations or splines of said one set being spaced from the serrations or splines of said second set to enable the serrations or splines to interlock when the containers are offset a short distance relative to one another.

14. A method of packaging a block of a soft product such as natural cheese, substantially as hereinbefore described with reference to the accompanying drawings.

1 5. A container for packaging a rectangular block of a soft product wrapped in film material substantially as hereinbefore described with reference to Figures 1 4 or Figure 9 of the accompanying drawings.