AU672563B2 - Method and apparatus for forming and hermetically sealing slices of food items - Google Patents

Description

S F Ref: 286826D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

I- Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Schreiber Foods, Inc.

425 Pine Street Green Bay Nisconsin 54307-9010 UNITED STATES OF AMERICA Vincent A. Meli, Michael A. Matharani, Ted A.

Brzezinski and David L. Shaft Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Method and Apparatus for Forming and Hermetically Sealing Slices of Food Items The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845 i METHOD AND APPARATUS FOR FORMING AND HERMETICALLY SEALING SLICES OF FOOD ITEMS BACKGROUND OF THE INVENTION The present invention relates generally to an )apparatus and method for packaging food items and more particularly to an apparatus and process for packaging and stacking food items in hermetically sealed individual slices.

Various methods and apparatus have been pro- .cposed and utilized for the manufacture and packaging of individual slices of food items such as cheese. Although the available apparatus and methods are suitable for the packaging of individual slices, they are not without disadvantages.

6 Typically, the package for the individual i slices is formed from a continuous film or web of a Sthermoplastic material; The web is first folded in Vfolded condition. As used herein, the term V-folded condition refers to a length of material which has been .Lfolded over onto itself so as to form what may subsequently be identified as a front sheet and a rear sheet which are joined by the fold at the bottom, so as to approximate the letter in cross section. The web is typically folded such that the rear sheet is longer Zthan the front sheet to define a flap section in the rear sheet, which extends beyond the top edge of the front sheet. The flap section is typically folded over onto the front sheet to form a tubular web.

are flattened. Subsequently cross-seals are formed along the longitudinal length of the tubular web at predetermined intervals. After the tube is crosssealed it is severed along the cross-seals in order to Sproduce the individually wrapped slices of cheese.

Several processes presently exist for providing the transverse or cross seal.

In one commonly used 1iechod, the cross-seals are formed by subjecting the flattened web (with the ioinserted cheese) to pressure, at the desired location, to form the transverse cross seal. The pressure is applied such that an ultra thin layer or film of cheese

-I

is left in the transverse sealing section. The ultra thin layer or film of cheese acts as an adhesive to nseal the two layers of the plastic web together. After this "cheese" seal has been formed, the web is severed at the sealed sections to define individual slices cf S cheese.

Although the "cheese" seal provides an ,adequate seal for the individual slices of cheese, the '.shelf life of the cheese product after, it is packaged is not as long as would be desirable. This is due to the fact that the cheese seal is a relatively weak seal which will eventually deteriorate and which allows air o2 4 to enter into the slices under ordinary atmospheric conditions. The slices will soon dry out or spoil.

Other methods of providing a transverse cross-seal have also been disclosed. For example, U.S.

Patent No. 4,586,317 (Bussell) discloses an arrangement 3for forming a seal in packaging material (such as processed cheese) which utilizes a sealing element having a finite number of small channels in the surface. The packaging film is co-extruded or laminated to include an inner sealing layer of rela- 3<'tiVely low thermal plastic melt temperature and an outer layer which does not melt under sealing conditions. The tube is heated and compressed 3 transversely by the sealing elements thereby sealing the internal layers of the packaging film together.

Although the apparatus and method disclosed in this patent provide a suitable cross-seal, the finished .product suffers from the same disadvantages that are described above. Since the longitudinal seal is formed by providing a flap in the V-folded condition web and simply overlapping the flap with the upper surface of the front sheet of the web, a poor seal is formed.

ioThus, air and other atmospheric products will enter into the wrapped slices of cheese, reducing the shelf life of the product: Therefore it would be desirable to provide an individual slice of cheese which is wrapped in a :package which is hermetically sealed on all sides. To accomplish this, a hermetic seal must be formed along the longitudinal edge of the web as well as along the transverse or cross-seals. A hermetically sealed package would have several advantages. For example, a dhermetically sealed slice would permit immersion for cooling and sanitizing. Further, a hermetically sealed slice is essential to aseptic packaging.

For purposes of manufacturing economy, it would be desirable to provide the longitudinal seal and cro..v-seals in a continuous process. Some presently ava-lable methods, however, form seals in an intermittent fashion. Typically, in these presently available methods, a seal is formed by heated jaws which reciprocate between an open and a closed Acposition. When the jaws close, they seal the desired section of the web. After the section has been sealed, the jaws retract and the web is moved for the next section which is to be sealed. This process, however, has obvious disadvantages. The web must be stopped and started in accordance with the reciprocating movement of the jaws. Such a device is disclosed for example in U.S. Patent No. 2,460,460 (Langer).

Another problem which is encountered in the processing and packaging of cheese slices (as well as in the packaging of other products which are packaged in slices) is the lack of an available simple and efficient stacking process. Typically the stacking of slices into packages containing a plurality of slices is performed by an operator or a stacking machine. The available stacking machines, however, do not provide the required degree of efficiency and precision in the packaging of different stacks of cheese. It would be desirable to provide a stacking arrangement or process which would permit slices from a single wrapping machine to be stacked in a plurality of different stacks. It would be even more desirable to provide an arrangement which would allow the operator to selectively vary the number of slices in the stacks from one stacking job to the next. Preferably the stacking arrangement will also accurately stack slices of cheese from a relatively fast production line in a plurality of different stacks.

It is an object of the present invention to overcome or substantially ameliorate at least some of the above disadvantages.

41 oooo

I

ei eeu eeoeo i %lhmt nl'lt 17.R SUMMARY OF THE INVENTION There is disclosed herein an apparatus for stacking slices of a product in at least one stacking location, the apparatus comprising: a belt having a plurality of apertures, the belt being arranged such that at least part of the belt is disposed above the at least one stacking location; means for moving the belt such that the belt travels over the at least one stacking location, the bottom of the belt facing the at least one stacking location; vacuum means for providing vacuum through the apertures of the belt along a product-holding section of the belt, the vacuum being continuously provided during a stacking operation such that the slices of the product are maintained on the belt; a selectively engageable air ejector operatively connected to provide positive air pressure through the apertures in the belt at an air ejector location, the air ejector location being disposed downstream of the product-holding section of the belt at the beginning of the at least one stacking location, the air ejector being continuously operated during a stacking operation to provide positive air pressure to the apertures at the air ejector location simultaneously with the vacuum being provided through the apertures at the product-holding section of the belt such that the leading edge of a slice emeoo of produce is urged off the belt by the positive air pressure as the slice is moved past the apertures at the air ejector location.

R

o1 ,z Irl.\lli~~lonn?-r. nm -6- In a preferred embodiment, means are provided for selectively engaging or disengaging the positive air pressure at the leading edge of each stacking location. This stacking arrangement thus provides an apparatus for stacking a predetermined number of wrapped cheese slices being produced at a relatively rapid production rate into a plurality of stacks.

Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be obtained by means of the combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of a preferred embodiment of an apparatus and method for packaging a food item, including a longitudinal sealer, a cross sealer, and a stacker.

FIG. 2 illustrates a preferred embodiment of a slice of cheese which has been sealed (with the flap folded over).

FIG. 3 illustrates the slice of cheese illustrated in FIG. 2 with the flap unfolded.

FIG. 4 is an illustration of a preferred embodiment of a longitudinal sealer and p 20 flattening means.

/VTr 0 FIG. 5 is a schematic representation of the cross sealer and stacker illustrated in FIG. 1.

FIG. 6 is a top view of a preferred embodiment of the stacker illustrated in FIG. 1.

FIG. 7 illustrates a side view of the preferred embodiment of the stacking arrangement illustrated in FIGS. 1 and 6.

FIG. 8 is an illustration of a preferred embodiment of a longitudinal sealer.

FIG. 9 illustrates an enlarged side view of a section of the cross sealing arrangement illustrated in FIG. 1.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT Reference will now be made to the drawings wherein like elements are referred to with like reference numerals throughout the various drawings. Referring specifically to FIG. 1, a preferred embodiment of the arrangement and process of the present invention including the longitudinal sealer, cross sealer, and the stacker is illustrated.

Cheese is first processed, in a manner known in the art, by cheese processing means 10. The processed cheese is then transferred, in a known manner, from the "cheese processing means 10 into a fill

C

C

N.

Im-lihktnnnn7Rcr 8 tube arrangement 12 which is used to insert the processed cheese into a tubular web made of thermoplastic material.

In more detail, the tubular web of thermomaterial is formed by providing a continuous film or web of thermoplastic material and folding the web into V-folded condition, in a manner known in the art. After the web of thermoplastic material has been folded into the V-folded condition, a longitudinal seal o is formed at a sealing station 20 (in a manner described in more'detail below). Nip rollers 16 are provided to secure the seal and continuously pull the web of thermoplastic material. After the longitudinal seal is formed at the sealing station 20 and leaves the 1Inip rolls 16, the cheese is inserted by means of the fill tube 12 into the tubular web. The web and cheese are then passed to a flattening station 22 (also described in more detail below). At the flattening station 22, the tubular web with the cheese is flat- Ac-tened to form'a continuous web or slice of cheese.

S..After the web has been flattened and formed into the film, the web is then passed through a cooling station 14. In one preferred embodiment, the cooling station 14 comprises a tank or container for holding a z2-cooling liquid, such as water. In this embodiment, the cooling station 14 may include a plurality of rollers .such that the web and cheese are passed through the tank in a winding fashion. Preferably the cooling station 14 is configured such that the web with the 3 cheese passes through the cooling water for approximately 20 seconds with the water being at between 32 0

F

and 50 0 F. This will take the cheese which usually starts off at a temperature of between 170 0 F and 180°F and cool the cheese down to approximately 50 0 F at the _iexiting end of 'the cooling station 14. Preferably, the cooling station includes a roller which is over driven to provide means for keeping the web taut. The cooling 9 station may also include scrapers and/or air-blowers (not shown) to dry the web as it exits from the cooling station 14. It will be recognized by those skilled in the art that other suitable cooling means may also be used.

After leaving the cooling station A4, the web is conveyed, preferably by a pair of driven feed belts 39, to the station which forms the cross seals.

A loop control means and tensioning means 41 may be ic.provided. The transverse or cross sealing station includes a first member 42 with a plurality of heated jaws 46 and an opposed bottom member 44 with jaws with opposed engaging surfaces. The cross sealing station 40 provides a hermetic seal 102 transverse to the longitudinal or forward moving direction of the web. The web now includes a plurality of slices of cheese 100 which are hermetically sealed. The cross sealing station 40 is described in more detail below.

After the transverse or cross seals have been )formed, the web is then conveyed to a cutting station 60 to separate the individual slices of cheese 100. The station 60 includes means for cutting the web along the cross-seal to define the individual slices. The station 60 also preferably includes a J)stacking arrangement 70 which stacks the slices 100 being conveyed from the cross sealing station 40 into a plurality of stacks. The stacking arrangement is described in more detail below.

THE LONG SEALER r:o Referring now specifically to Figs. 4 and 8, a preferred embodiment of the longitudinal sealing arrangement 20 and the flattening arrangement 22 are illustrated.

The preferred embodiment of the longitudinal 2.-;or long sealing arrangement 20 provides a novel and advantageous apparatus and process for forming the 10 longitudinal seal in the web without stopping the web in an intermittent fashion. The sealing station includes a pair of stationary heated plates 24, Each plate includes an undulating surface which forms San important part of the longitudinal sealer 20. The undulating surfaces of the plates 24, 25 are opposeand the plates 24, 25 are disposed such that a fixed gap or distance exists between the opposed undulating surfaces. The gap between the undulating surfaces of rCthe plates 24, 25 is fixed such that as the front and rear sheets of the open longitudinal end of the web are conveyed between the undulating surfaces, the front and rear sheets of-the web are forced into intimate contact with each other.

In a preferred embodiment the gap between the undulating surfaces is tapered having a wider gap at o the top than the bottom with an average gap distance of approximately 1/16 of an inch. Means are provided for heating the two plates to a temperature sufficient to S-form a longitudinal hermetic seal as the web is S conveyed between the two plates 24 and 25 without physically clamping the two surfaces together. The heating may be provided by any suitable heating means, for example, an electric heater 26 which is inserted through an aperture 23 in each plate 24, 'e 25. The plates are heated to a temperature sufficient to form a hermetic seal between the two sheets of the web, for example, the plates may be heated to a temperature of approximately 260 0 F. Nip rollers 16 are 3,provided after the sealing plates station 20 to secure the seal and pull the web through the longitudinal sealer.

In a preferred embodiment, the fill tube 12 extends down into the web such that the exiting end of -Vche fill tube 12 is disposed after the nip rollers 16.

In this manner, the cheese is inserted into the web I I after the longitudinal seal has been formed and a tube has been defined.

In a preferred embodiment, a bubble control element 28 is disposed before the flattening station 22. The bubble control unit 28 functions to determine the amount of cheese which is being inserted into the web. In this manner, the flow of cheese may be controlled as appropriate for the speed of the web and the desired thickness and weight of the slice.

,I After the cheese is inserted into the tubular web, the tubular web is conveyed to a flattening station 22. The flattening station 22 includes a first or upper set of juxtaposed rollers 32, a lower set of juxtaposed rollers 34, and a pair of opposed belts i- Each belt 30 is disposed around one set of rollers 32, 34. As the web with the cheese inserted therein passes between the two belts, the cheese is flattened to form a web comprising the tubular thermoplastic film and a continuous slice of cheese. Means 36 are provided K.- 2 Ithe flattening station 22 for adjusting the distanc between the belts 30 to control the thickness of the web of tubular thermoplastic material and cheese.

As illustrated in Fig. 3, the web is formed into a tubular section with a hermetically sealed &Llongitudinal seal 106 (the longitudinal seal is o represented in Fig. 3 by the section illustrated between the arrows) Preferably, the web is sealed along the top longitudinal edge of the front face of the web such that a flap portion 104 is defined as -tillustrated in Fig. 3.

After the longitudinal seal 106 is formed, the web is conveyed through the cooling station 14, as described above, and then the flap 104 is folded over onto the front face of the web as illustrated in '"FiJ. 2. The flap may be folded over in a manner known in the art before the web reaches the cross-sealing station 40. Preferably, the flap 104 is partially 12 sealed at the cross seal sections to the front face of the web at the cross sealing station THE CROSS SEALING STATION Referring now specifically to Figs. 5 and 9, Ta preferred embodiment of the cross-sealing arranygment is disclosed. The cross-sealing arrangement includes an upper sealing member 42 and a lower sealing member 44, with each of the sealing members including a plurality of opposed jaws or cleats 46 and 50 respeciCtively. As best illustrated in Fig. 9, the sealing members 42 and 44 are arranged such that as the web is conveyed through the sealing station 40 between the upper cleat 46 and the engaging lower cleat 50 the top and bottom layers of the film web are merged together i.in the desired cross sealing section, The cleats 46 of the. upper member 42 are heated to the sealing temperature, in a manner known in the art. For example, the top cleat 46 may be heated by an electrical heater and brush arrangement. The cleats 46 and 50 may be made of ?-any suitable material such as aluminum. The top cleat 46 preferably includes a removable section 48. The engaging bottom cleat 50 also preferably includes a .removable section 45, which is made of a softer material than the top mating section 48 of the .(cldat 46. For example, the removable section 48 of the top, cleat 46 may be made of a metallic material such as aluminum and the removable section 45 of the lower cleat 50 may be made of a resilient material such as polyurethane.

3o For.purposes of quality control and to achieve uniformity in the cross seals, each of the heated cleats 46 includes a thermostat 54 which controls the temperature of each individual cleat.

Therefore the temperature of each cleat can be adjusted ;-separately.

13 Means are provided for urging the two opposed cleats to engage the web of cheese as it is conveyed through the sealing station 40. As illustrated in the figures, in the preferred embodiment, the means for z-urging the cleat together comprises a track and chain arrangement. Each of the cleats is attached to a chain arrangement which rides on a track 56, 58. The chain arrangement, illustrated best in Fig. 9, includes sections of chain including rollers 52 and 53 which are cattached at spaced intervals to the links of the respective chain. The rollers 52, 53 ride on elongated circular tracks 56,:58, respectively. The elongated circular tracks 56, 58 are disposed such that the cleats 46 and 50 ride in engaging relationship for a predetermined interval (discussed in more detail below).

Preferably the web of cheese in the tubular film is conveyed through the opposed jaws 46, 50 of the sealing members 42, 44 such that a hermetic seal is S..formed between the two inner layers of the web material. More preferably, the seal is formed such that when after the seal has been made and the package is pulled apart at the seal, the seal will break. This is opposed to the seals which are presently made A)3-wherein after the seal has been formed and the package is pulled apart, the seal is broken by delamination, that is, by breaking the bond between the top nonsealing layer of and the inner or sealing layer of the sheet of the web. This preferred packaging arrangement CAis achieved by proper selection of the thermoplastic material. For example, one preferred material comprises a polypropylene layer coextruded with a polyethylene sealant layer with an intermediate adhesive layer.

In a preferred embodiment, the sealing temperature is between 260°F and 280°F and the jaws travel with the web from the first point of engagement 14 to the point of disengagement for approximately one second. The pressure exerted between the two opposing jaws on the sealing section 106 is such that substantially all of the cheese is removed from between the two )layers of the thermoplastic web material in the crosssealed areas.

Suitable means are provided for driving the two chain arrangements in the sealing members 42 and 44. The slices of cheese are defined in the section 1between the jaws. Preferably, the sealing section of the jaws 46 and 50 are such that the cross seal 102 between adjacent cheese slices 100 is approximately 1/4 of an inch. The cleats 46, 50 are spaced in their respective chains such that the distance from the :6-beginning of one slice to the beginning of the next slice (including the cross-seal sections 102) is approximately 3-1/2 inches.

This arrangement allows for high speed production of the individual slices of cheese 100.

i" 0 ,Since the heating cleats 46 and the mating 50 ride or move along with the cross seal for a fixed period of time, the web may be continuously moved at a relatively .fast pace providing a rapid production rate. For •example, the web may be moved at approximately 300 'feet/minute or such that over approximately 1,000 slices are produced per minute.

THE CUTTING AND STACKING ARRANGEMENT After the cross seals 102 have been formed, the web is then conveyed to a cutting station 62. Loop ccontrol means 63 and tensioning means 67 are also provided. Referring specifically to Figs. 5 and 7, the cutting station includes a pair of spindles 64, 66 with means for severing the web at the cross seals such that individual slices are defined. After the web has been 3'cut' to form the individual slices, the slices of cheese 100 are ready to be stacked into individual stacks for 15 packaging. The slices 100 are discharged from the cutting section 62 and disposed on the stacker Referring now specifically to Figs. 6 and 7, a preferred embodiment of the stacker of the present -invention is disclosed. The stacker 70 provides an efficient way for selectively stacking a predetermined number of the cheese slices 100 being produced by the previously discussed forming, sealing and cutting arrangement into a plurality of stacks.

t)0 The stacking arrangement 70 comprises a porous conveyor belt, which is preferably in the form of an endless belt 72. Preferably, the endless belt 72 include a plurality of apertures such that the belt 72 is approximately 25% or more open. A vacuum system 78 lis provided on the inside of the endless belt 72 such that the slices of cheese 100 are maintained on the outside surface of the endless belt 72 by the atmospheric pressure differential pressure created by the vacuum system 78. Preferably the endless belt 72 rotates about two rollers or drums 74 and 76 which are rotated by means known in the art. The vacuum system 78 provides sufficient vacuum such that the slices of cheese 100 adhere to the surface of the belt 72 as the belt is advanced. That is, the slices of cheese 100 .•'are maintained on the belt as the belt travels around the drum 76 and further are maintained even in an upside down position as the slices 100 travel around and are disposed on the bottom of the stacker Thus, the vacuum of the vacuum system 78 is sufficient ^tto overcome the force of gravity pulling the slice of cheese 100 down when it is on the bottom of the belt 72.

A plurality of stacking locatio:is 82a-82f are provided to accommodate the rapid production rate of %gthd wrapping system described above.

An air ejector 80a-80f is provided at the front of each stacking location 82a-82f. The air 16 ejector 80a-80f, when actuated, applies air pressure at the leading edge of the cheese slice 100 as it travels on the belt 72. The ejector 80a-80f provides the positive air pressure through the apertures of the belt as the slice passes under it to thereby override the vacuum and "peel off" the cheese slice 100 as it is being conveyed past the ejector 80a-80f. In this manner, the force of gravity releases the slice 100 into the desired stacking location. Preferably, an O"inclined plate or ramp plate 90 is provided before the front edge of each stacking location 82a-82f. This ramp plate 90 assures that if the cheese slice 100 is released from the conveyor belt 70 before it is fullyin the stacking location, the cheese slice 100 will r -slide onto the plate 90 and be conveyed into the oee stacking location. A photo sensor 84 is provided at the beginning of the stacking location for programming the number of slices 100 to be dropped at each stacking location 82.

e a 4 In-a preferred embodiment, a particularly advantageous stacking system is configured such that an intermediate slice receiving means is used to temporarily hold the first few slices being dropped into the stacking location 82. In one preferred embodiment, the x-intermediate slice receiving means comprises a first or upper set of retractable fingerlike members 86. Preferably, a lower set of retractable fingerlike members 88 are also provided. The upper set of retractable fingers 86 are disposed at an intermediate level nZbetween the top of the particular stacking location and the bottom of the stacking location. This upper set of stacking fingers 86 acts as an intermediate landing stop for the cheese slices 100 as they are peeled off into the particular stacking location. After a prede- ;~termined number of slices have fallen on to the upper set of fingers 86, the fingers 86 are retracted such that the slices of cheese 100 which were stacked in the 17 particular stacking locations fall onto the lower sec of fingers 88. The lower set of fingers 88 is particularly important where the number of slices 100 that is to be stacked in each stacking location is large.

"For example, some projects may require as much as a four inch stack of slices of cheese 100. The advantages of the upper set of fingers 86 are best illustrated by describing the trajectory of the cheese slices 100 if this upper set of retractable fingers 86 iowere not present. As the slice 100 would be peeled off by the ejector 80, the slice 100 would begin to fall at an, angle with the leading edge of the slice 100 having the lowest position. If the slice 100 were to fall a sufficient distance, it would tumble rather than being r flatly deposited in an orderly fashion thereby disrupting the stacking process. The upper fingers 86 provide o an intermediate stop for the slices 100. The slice 100 only falls a short distance to the upper set of finger 86. Thus, the stability of the stack is maintained.

After a number of 100 slices have been disposed on to the upper set of fingers 86, the upper retractable fingers 86 are retracted and the entire stack of slices 100 falls onto the lower set of fingers 88. Since a number of slices 100 have already been deposited on the stack, the slices 100 which are now being peeled off from the conveyor 72 and dropped onto the existing stack of slices 100 will have a shorter distance to fall. That is, the distance 3othat a falling slice 100 will have to fall will only be the distance between the conveyor belt 70 and the top of the stack. After all of the slices 100 that are to be included in a particular stack have been stacked, the lower set of retractable fingers 88 is retracted and'the stack of slices 100 falls onto the conveyor table 92.

18 In another preferred embodiment, the intermediate slice receiving means may comprise an elevator arrangement which is initially raised to a predetermined intermediate height and is lowered to accom- Emodate the rate at which the slices are being stacked in the stacking locations. Preferably, in this embodiment, the elevator is lowered to deliver the stack to a conveyor table 92 after the last slice 100 has been dropped in the stack.

Preferably means such as a programmable controller or microprocessor are operatively connected to the respective ejectors 80a-80f at each stacking location 82a-82f such that the number of slices 100 in the stacks 82a-82f can be selectively adjusted. The jzcontrolling means will also make it possible to only fill certain stacking locations and eliminate other stacking locations. In one particularly advantageous embodiment, the ejectors 80a-80f and the control means are operatively configured such that each sta,:kng 'colocation 82a through 82f is successively or 'stetially filled. In this embodiment, before any ar tae stacking locations 82a-82f have been filled, all of the ejectors provide positive pressure at the front edge of each stacking location. As the slice 100 is conveyed 9past the first ejector 80 (corresponding to the first stacking location 82a), the first ejector 80 provides positive pressure to peel the slice 100 off the conveyor belt 72 and into the first stacking location 82a.

After the predetermined number of slices 100 have been dropped into the first stacking location 82a, the positive.pressure provided by the ejector means 80a at the first stacking location is terminated. Thus, the vacuum pressure from the vacuum means 78 will continue to hold the next slice 100 on the conveyor belt 72 ;Suntil it reaches the ejector 80a at the second stacking location 82b. The ejector 80b at the second stacking location 82b will continue to operate until the second 19 stack has been filled with the predetermined number of slices. After the second stack has been filled, the ejector 80b at the beginning of the second stacking location 82b will be turned off and thus the next slice '100 will be conveyed to the third stacking location 82c. This process will continue until the predetermined number of slices for each stacking location is complete. This process is particularly advantageous since the vacuum system does not have to be repeatedly icdisengaged. The air ejectors override the vacuum without the need to discontinue its operations.

Preferably as illustrated in Figs. 1 and the stacks from each individual location 82a through 82f are disposed onto another conveyor 92 which is 1Idisposed such that it advances in a direction transverse to the direction of movement of the endless belt 72 of the stacker 70. In this manner, the stacks of the slices 100 are conveyed away from the stacker 72 to a location where they may be further processed either rmanually or automatically.

:Therefore, the packaging and stacking system of the present invention provide a means for hermetically packaging individual slices of cheese at an efficient and rapid production rate. The sealing provided by the present invention provides a hermetic seal along the longitudinal edge of the web.

After the cheese is inserted in the tubular web hermetically sealed cross seals are formed. This arrangement provides a hermetically sealed package of cheese i-which will have a substantially longer shelf life than the presently available sliced cheese products. Additionally, the longitudinal seal and the cross seals are provided in a manner which permits continuous movement of the web without the intermittent action of some 3presently available sealing systems. The slice which is produced and packaged according to the present invention provides a preferred final packaged product.

20 The seal is formed between the two inner layers of the low thermal melt material such that the seal is broken when the packaging materials are pulled apart to open the individual slice. Unlike presently ,,available packages, wherein the sealing layer is delaminated from the top layer of the packaging material and when the package is opened a rough tear is made which leads to "stringing". With the package of the present invention, the bond is broken between the )Otwo sealing layers of polyethylene and a nice clean opening is provided which eliminate the stringing problem.

Additionally, since the polyethylene may be used as the sealing layer, the packaging material is iSeasily released from the processed cheese. This :obviates the need for items such as a sheer pump to Sprocess the cheese so as to have a less cohesive texture and provide a better release. The process and apparatus of the present invention also permit the top o ,layer of the packaging material to be made of a polypropylene material. This is particularly advantageous since polypropylene is less expensive than presently used materials such as MYLAR.

The present invention also provides an effio tcient stacker which takes slices produced by a relatively rapid production machine and stacks the slices In a plurality of stacks. The number of slices may be selectively varied in the stacking locations allowing S"for greater control in the production process.

The foregoing description of the preferred embodiments of the present invention has been presented for purposes of illustration and description. The described embodiments are not intended to be exhaustive or to limit the invention to the precise form dis- 9closed. Obviously many modifications and variations are possibl.e in light of the above teachings. The embodiments which were described were chosen in order 21 to best explain the principles of the invention and its practical applications. It is intended that the scope of the invention be defined by the f llowing claims, including all equivalents.

oe ee s

Claims (11)

1. An apparatus for stacking slices of a product in at least one stacking location, the apparatus comprising: a belt having a plurality of apertures, the belt being arranged such that at least part of the belt is disposed above the at least one stacking location; means for moving the belt such that the belt travels over the at least one stacking location, the bottom of the belt facing the at least one stacking location; vacuum means for providing vacuum through the apertures of the belt along a product-holding section of the belt, the vacuum being continuously provided during a stacking operation such that the slices of the product are maintained on the belt; a selectively engageable air ejector operatively connected to provide positive air pressure through the apertures in the belt at an air ejector location, the air ejector location being disposed downstream of the product-holding section of the belt at the beginning of the at least one stacking location, the air ejector being continuously operated during a stacking operation to provide positive air pressure to the apertures at the air ejector location simultaneously with the vacuum being provided through the apertures at the product-holding section of the belt such that the leading edge of a slice of produce is urged off the belt by the positive air pressure as the slice is moved past the apertures at the air ejector location.

2. Apparatus as claimed in claim 1, wherein the belt comprises an endless belt and the means for moving the belt comprises means for advancing the belt.

3. Apparatus as claimed in claim 2, wherein the vacuum means provides o vacuum through the apertures around the endless belt at least up to the location of the air ejector. 25

4. Apparatus as claimed in any one of claims 1-3, comprising a plurality :l E of sequentially disposed stacking locations including respective air ejectors for each stacking location and further comprising means for selectively engaging and disengaging the air ejector at each stacking location.

Apparatus as claimed in claim 4 which includes means for counting the number of slices deposited at each stacking location.

6. Apparatus as claimed in any one of claims 1-5, further comprising intermediate slice receiving means in the at least one stacking location for receiving the slices of a product at a location intermediate to the top and the bottom of the at least one stacking location.

7. Apparatus as claimed in claim 6, wherein the intermediate slice receiving means comprises a plurality of retractable fingers.

8. Apparatus as claimed in claim 6, wherein the intermediate slice receiving means comprises an elevator and means for lowering the elevator at a rate ik INAI:\IIhIOO3100 7'-lf 23 sufficient to provide room for a subsequent slice and to lower the first slice of product stacked in the at least one stacking location to a predetermined elevation after the last slice of product is stacked in the at least one stacking location.

9. Apparatus as claimed in claim 1, further comprising means for selectively engaging and disengaging the respective air ejector at each stacking location.

Apparatus as claimed in claim 9, further comprising means for counting the number of slices deposited at each stacking location.

11. An apparatus for stacking slices of a product in at least one stacking location, substantially as hereinbefore described with reference to Figures 1, 5, 6 and 7. DATED this Twenty-ninth Day of January 1996 Schreiber Foods, Inc. Patent Attorneys for the Applicant SPRUSON FERGUSON D r ~s I o o D o o -V C) Z N:\libtt1100837:nFD Method and Apparatus for Forming and Hermetically Sealing Slices of Food Items ABSTRACT An apparatus and method are provided for forming a hermetically sealed package for a slice of a food item (100). A web of thermoplastic material is first formed into a tubular arrangement with a hermetic longitudinal seal. To form the tubular arrangement, means (12) are provided for folding a continuous web of thermoplastic material into V-folded condition and (20) for continuously forming a hermetic seal along the open longitudinal edge of the V-folded web. The hermetic seal is formed between the inner surfaces of the front and rear faces of the web to define a tubular web member. The food item which has beem formed into a soft mass is then inserted into the tubular member and the tubular member is flattened to form a thin film tube. Means (40) are provided for forming a hermetically sealed cross-seal which are disposed substantially transverse to the longitudinal forward moving direction of the web, *o maa4254W I