US3491504A - Method and apparatus for vacuum skin packaging - Google Patents

Description

Jan. 27, 1970 Filed Oct. 2, 196'? W. E. YOUNG ETAL 5 Sheets-Sheet l W l| HI I a 30 32 252 if: 1 g

Fig.4 Fig.5

INVENTORS WILLIAM E. YOUNG WILLIAM R PASCO ROBERT O. WOLFELSPEQGER y @M AGENT Jan. 27, 1970 w. E. YOUNG ETAL 3,491,504

I METHOD AND APPARATUS FOR VACUUM SKIN PACKAGING Filed Oct. 2. 1967 5Sheets-S1 1eet 2 "lif -:55; 21

INVENTORS WILLIAM E YOUNG WILLIAM R- RASco ROBERT 0. WOLFELSPERGER AGENT 5 Sheets-Sheet .5

Jan. 27, 1970 w. E. YOUNG ETAL METHOD AND APPARATUS FOR VACUUM SKIN PACKAGING iled Oct. 2, 1967 Jan. 27, 1970 w. E. YOUNG ETAL 3,491,504

. METHOD AND APPARATUS FOR VACUUM SKIN PACKAGING Filed Oct. 2, 1967 5 Sheets-Sheet 4 INVENTORS WILLIAM E YOUNG WILLIAM R. PA sco ROBERT o. WOLFELSERGER BYEDMEZEZQLT AGENT Jan. 27, 1970 w. E. YOUNG ETAL 3,491,504

METHOD AND, APPARATUS FOR VACUUM SKIN PACKAGING Filed Oct. 2, 1967 5 Sheets-Sheet 5 Fig.2/

HII 7 "W INVENTORS WILLIAM E. YOUNG WILLIAM R. R A sco ROBER WOLFELSPERGER BY Pay/A EBA? AGENT United States Patent U.S. Cl. 5322 44 Claims ABSTRACT OF THE DISCLOSURE A method of forming a skin package particularly for food products such as fresh meats, fowl and the like said package being formed in the presence of a vacuum and with a covering sheet of thermoplastic film held by its edges while being softened by heat to a condition for draping. The product as it is being packaged is carried on an impervious base member having its supporting face adapted for pressure sealing to the heated film. In an evacuated chamber, the product and base member are pushed or brought to and into the heated film to drape the film over the product and bring the heated film into at least a partial sealing contact with the base member, after which the vacuum supply to the chamber is shut off and atmosphere is admitted to the chamber and outside the package in such a manner as to push the film and base member tightly around the product and into a fully sealed condition to one another.

BACKGROUND OF THE INVENTION Field of the invention This invention pertains to the general class of package making and more particularly to the subclass of contents material treating with vacuum or inert atmosphere; to the subclass of methods with contents treating with vacuum or gas,and the subclass of methods, receptacle formed and subsequently filled. Also pertinent to the method of this invention is the general class of Foods and Beverages and to the particular subclasses of preservation, hermetic sealing-packaging, wrapping and casing, and also particularly to the subclass of meat packaged with hermetic sealing, and the subclass of hermetic sealing with inert gas.

Description of the prior art The packaging of food products such as meat and the like with heated film and vacuum has been the subject of many patents and the broad concept of forming a package in or with the assistance of vacuum is well known in the art. These patents are usually directed toward problems in the packaging of processed sliced meats, foods and the like, generally in which the voids in the product are at a minimum and where the size of the grouping is generally of a uniform nature. There are, however, many problems in packaging fresh meat products such as fowl and the like in which there are voids in the product which persist during and after the packaging of the product. When the void in the product is under a negative or reduced pressure, the package cover tends to remain tight to the product. When the void in the product is at or near atmospheric pressure, the package tends to become loose in part or may become completely loose, particularly if, in the transport thereof, the product is partially crushed or is reduced in size.

Representative of the patents in the prior art directed toward packaging processed meat are U.S. Patent 3,290,858 to Eberman of Dec. 13, 1966; U.S. Patent 3,491,504 Patented Jan. 27, 1970 "ice 3,299,608 to Orloff of Jan. 24, 1967; U.S. Patent 3,010,262 to Rumsey, Jr. of Nov. 28, 1961; U.S. Patent 3,060,652 to Eckman of Oct. 30, 1962; U.S. Patent 3,177,106 to Seefluth of Apr. 6, 1965, and U.S. Patent 3,303,628 to Lovas of Feb. 14, 1967. These patents and others known to the art are directed to more or less uniform conditions, whereas this invention is directed toward providing a method for packaging irregularly shaped products of varying sizes.

In the skin packaging of cold meats and in irregularly shaped items such as hardwareand the like, the "packaging in the presence of a vacuum contemplates the preforming of the blister portion of the package before the blister is brought to the product prior to the step of packaging and sealing. In the present invention the thermoplastic cover or upper member is not preformed but in the warmed draping condition is brought into engagement with the product to conform to the exterior shape of the product and to use the very minimum of film in providing this shape.

It is also contemplated that those products which may be packaged by the method of this invention will include items such as hardware, stationery items such as letter openers, inkwells and other irregularly shaped objects.

The method of this invention provides for a package in which the product is packaged in the presence of a vacuum and with the resulting contents after packaging often remaining under a reduced pressure or vacuum. Products such as fowl, fish and fresh foods in which voids are a natural occurrence are packaged in a tightly wrapped film and with the film formed and remaining in a taut condition for a period of time, this period depending on the oxygen permeability of the film.

SUMMARY OF THE INVENTION This invention provides a method whereby products such as fresh meat, fowl, fish and irregularly shaped items are packaged so that voids in the product being packaged are brought to a condition of reduced pressure. The package so formed has the upper package portion of a thermoplastic film which provides at least a substantial portion of the package. This resulting package may have its inner portion under reduced pressure so that the cover is maintained in a taut condition. The film portion of this package tightly conforms to the shape, usually irregular, of the product being packaged. The method of this invention contemplates that the product to be packaged is placed upon a bottom member of film or upon a tray or like member in which the upward surface is adapted for heat sealing to a thermoplastic film such as ionomer, polyethylene and the like when this film is brought into a heated condition. In the method as shown and to be hereinafter more fully described, the product is placed upon a base portion which is arranged upon a movable platen carried in or movable to a lower chamber portion. An upper chamber is movable towards this lower chamber portion and when they are joined they form a hermetic seal, whereupon they are operatively connected to a supply of vacuum. The chamher at another or later period of operation is brought to a condition of or may be opened to the atmosphere.

In the way of the movement of the upper chamber there is a film transporting means adapted to advance a strip of ionomer, polyethylene or a like film in the way of the upper chamber. Upon the placing of the product such as fresh meat, fowl and the like upon the base portion, the upper chamber is caused to be moved into engagement with the lower chamber to provide a hermetically sealed chamber. The strip of thermoplastic film provides an upper film member which is supported by the chamber edges and is disposed above the product. The interior of this sealed chamber is then brought under vacuum or to a condition of reduced pressure. While the desired interior condition of the chamber is being established, heat is caused to be directed towards the upper film to cause the film to soften, whereupon the low p.aten is caused to be raised upwardly, pushing the product into the heated film. The product, as it engages the film locally, cools the film causing this portion to stretch no further. The sides of the film not in contact with the product are allowed to drape over the product and come in the way of the bottom member upon the movable platen. The upper film is in a heat scalable condition as it touches the lower member and as it touches the lower member the package is brought into a more or less attached or sealed condition.

The upward movement of the platen is stopped at a determined position and the vacuum in the chamber is shut oiT, after which the chamber is opened to the atmosphere. The portion of film that has not come in contact with the product is caused to be moved towards the product and to the bottom member resting upon the platen. Upon the engagement therewith the package is heat sealed by atmospheric pressure and the cooling of the film stops any further stretching. At the time that the upper chamber is exposed to the atmosphere the heat directed towards the upper film may be cut off so that the draping ability of the heated film is terminated.

After the package has been formed and the chamber brought to atmospheric condition, the chamber portions are separated and the package is removed from the movable platen. Upon the exposure of the atmosphere any vacuum within the voids of the package causes the package to tightly engage the product to retain the film in a taut condition.

In an automatic or semiautomatic embodiment of this invention it is contemplated that the upper film may be warmed prior to its movement in the way of the upper chamber. This warmed film may or may not require further heating while in the chamber and during the step of skin packaging of the product.

It is also contemplated that in certain circumstances it may be desirable to warm at least a portion of the lower packaging member. This may be especially desirable where the lower packaging member is a heavier tray member. The tray-receiving carrier portion of the apparatus may be adapted for heating so as to warm each tray during a portion of the packaging process. Of course, a portion of the heat applied within the hermetically sealed chamber may warm the lower packaging member.

It is an object of this invention to provide a method whereby a product is skin packaged and sealed in the presence of a vacuum. During the packaging, heat is applied to an upper film, causing the film to become softened to a draping condition whereupon the product is pushed or moved into this film and in a hermetically sealed and evacuated chamber. This movement causes substantially even stretching of the draped film over the product. As the upper film meets a lower Support member, the portions forming the package are brought into a sealing condition. At a determined stage of the operation, the vacuum surrounding the package is cut off and atmosphere is permitted to enter the chamber to urge the 'pjackage portions against the product to Produce a package which is heat sealed without the use of pressure bars.

It is a further object of this invention to provide a method of skin packaging a product in a vacuum'chamher, said method of packaging being performed in a chamber having at least an upper and lower portion and with a means for advancing a strip of film in the way of opposite ends of the upper chamber so that as the chamber is closed, this film becomes the upper portion of the package and is suspended at a determined level. Means is provided for heating the film to a drape condition whereby the product is advanced to the heated film to bring the film over the product.

4 INTENT OF THE DISCLOSURE Although the following disclosure offered for public dissemination is detailed to insure adequacy and aid in understanding of the invention, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how it may later be disguised by variations in form or additions of further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirement of pointing out those improvements in the method and apparatus for vacuum skin packaging in which this inventive concept is found.

There has been outlined rather broadly the most important features of the method of skin packaging of this invention in order that the present contribution to the art may be more fully appreciated. There has been chosen a specific method, a modification thereof, and alternates thereof for the purpose of description of the invention and apparatus adapted for performing these methods are shown in the accompanying drawings forming a part of the specification wherein:

FIG. 1 represents a somewhat schematic sectional view showing a three-part chamber apparatus in which the method of this invention may be performed and with the apparatus open to receive the product to be packaged;

FIG. 2 represents the apparatus of FIG. 1 with the chamber in a closed position and with the upper being heated while vacuum is applied to the interior of the closed chamber;

FIG. 3 represents the closed chamber of FIG. 2 at a later stage of the method and with the product raised by a movable platen into the heated upper film and with this heated upper film draped over the product;

FIG. 4 represents the chamber of FIG. 3 at still a later stage of the method and with the vacuum shut oif and atmospheric pressure entering the closed chamber;

FIG. 5 represents the chamber of FIG. 4 with the top portion of the chamber lifted so that the skin package may be removed therefrom;

FIG. 6 represents a modified embodiment of the apparatus of FIG. 1 in which the apparatus comprises an upper and lower chamber portion and showing the product lying on a movable platen within the lower chamber;

FIG. 7 represents the apparatus of FIG. 6 with the chamber in closed position and with vacuum being applied to the hermetically sealed chamber, the movable platen moved downwardly into the lower chamber permitting heat to warm an upper film member;

FIG. 8 represents the apparatus of FIG. 7 with the movable lower platen moved to an upper position and pushing the product into the heated upper film to cause the film to drape over the product;

FIG. 9 represents the apparatus of FIG. 8 after the vacuum has been terminated in the chamber and with the chamber now opened to the atmosphere;

FIG. 10 represents an isometric view of a packaged pair of fowl skin packaged in accordance with the method of this invention;

FIG. 11 represents a partially diagrammatic side view of an automatic or semiautomatic apparatus for packaging fresh meat, fowl and the like, the apparatus particularly adapted for using trays as the bottom packaging member and arranged to sequentially package and seal the product in the presence of a vacuum;

12 represents an enlarged sectional view taken on the line 1212 of FIG. 11 and showing the chamber portion of the apparatus at two positions of operation;

FIG. 13 represents an enlarged fragmentary view of the chamber of FIG. 12 and showing in greater detail this chamber construction;

FIG. 14 represents an automatic or semiautomatic apparatus similar to the apparatus of FIG. 11 but adapted for the package in which the bottom portion of the package is a film portion;

FIG. 15 represents an enlarged sectional View taken on the line 15 of FIG. 14 and showing the chamber portion of the apparatus at two positions of operation;

FIG. 16 represents a somewhat diagrammatic sectional view of the apparatus of FIG. 11 at a beginning or chamber open stage in the sequence of operation;

FIG. 17 represents the apparatus of FIG. 16 in a next or chamber closed stage of operation;

FIG. 18 represents the apparatus of FIG. 17 at the final stage of package making and prior to opening the chamber for removal of the skin packaged product;

FIG. 19 represents a somewhat diagrammatic sectional view of the apparatus of FIG. 14 at a beginning or chamber open stage in the sequence of packaging process;

FIG. 20 represents the apparatus of FIG. 19 in a next or chamber closed stage of operation; and

FIG. 21 represents the apparatusof FIG. 19 at the final stage of package making and prior to opening the chamber for removal of the skin packaged product.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in which like numbers represent like members throughout the figures, there is shown in FIGS. 1 through 5 an apparatus in which the method of this invention may be performed. In this apparatus is provided a three-part chamber including an upper housing 25, a middle housing 26 and a lower housing 28. The upper housing is a diagrammatic representation of a usually generally square or rectangular housing within which there is mounted a pair of pivotally mounted heating elements 30 and 32. These elements are actuated by means not shown and may be moved from a vertical to a horizontal position for heating and then swung again to a vertical position after heating. The entire upper housing 25 is raised or lowered by means of a cylinder 34 carried upon a support 36 and by means of guides not shown is moved downwardly or upwardly in a precisely oriented relationship to the other chambers. Communicating with the interior of and extending upwardly from the housing 25 is a fluid conductor 38 which is connected to a valve and means for supplying either vacuum or atmosphere to the interior of the chamber, the valve and vacuum means being conventional are not shown.

Below the upper housing 25 is the middle housing 26 carried by means of support 40 and maintained in fixed position thereon. This middle housing in the packaging process becomes a separable part of the lower housing 28, as it is merely a matter of selection as to how many portions may comprise each chamber. In this middle housing a pair of heating elements 42 and 43 are indicated as carried in the side portions of the middle housing. These heating elements may be used instead of or in combination with the heating units 30 and 32 in the upper chamber. The heating elements 42 and 43 are contemplated as being movable into selected positions in the ionomer, polyethylene and the like, that portion of film which is advanced in the way of the upper opening of the middle housing provides the upper portion of the skin package.

Referring now particularly to the bottom chamber portion 28 of FIG. 1, there is mounted within this chamber a bottom platen carried by rod 52. Carried by platen 50 is a tray or bottom film member 54 having its upper surface adapted for heat sealing to film 48. The bottom chamber has a fluid conductor 56 connected to a valve and means, not shown, for supplying either vacuum and atmosphere to the lower chamber as steps in the packaging operation to be hereinafter described. Carrying and adapted to move the lower housing 28 is a piston 58 by which the lower housing is caused to be moved into hermetic sealing engagement with the middle housing portion 26.

Referring particularly to FIG. 2, it is to be noted that the upper housing 25 has been moved downwardly into engagement with the film 48 and also into hermetic sealing engagement with the upper surface of the middle housing 26 so that the film is trapped therebetween and is retained thereby. The platen 50, as it raises, mechanically clamps the film 48 against the bottom of the upper chamber 25, thereby mechanically separating the lower chamber 28, including middle chamber 26 from the upper chamber. The lower housing 28 has been moved upwardly by means of cylinder 58 to bring the lower housing portion into hermetic sealing engagement with the middle housing portion 26. Upon forming the hermetically sealed chamber, the fluid conductors 38 and 56 of the upper and lower chamber portions are opened to a vacuum supply so that the entire interior of the hermetically sealed chamber including that upper portion between the film 48 and the outlet 38 is under vacuum. Also under vacuum is that portion of the middle housing 26 and lower housing 28 between the film 48 and conductor 56. It is to be noted that the heaters 30 and 32 have been swung into a position parallel that portion the film 48 which is within the chamber. The heaters are activated so that the film exposed thereto is softened by heat into a draping condition.

At this step of operation a product 60 to be packaged has been placed upon the platen 50 and tray 54 and is ready for movement in a manner to be hereinafter described. It is to be noted that the vacuum in the upper and lower chambers is at the same level so that the film 48, although under the influence of heat from heaters 30 and 32, is neither urged upwardly or downwardly by a differential of chamber pressure. Film 48 in this embodiment of the apparatus is wider than the interior width of the chambers.

Referring next to FIG. 3, it is to be noted that the heaters 30 and 32 have been swung to their vertical position and that the lower platen 50 has been moved upwardly carrying the product 60 and its tray or bottom member 54 into the way of the heated film 48 so that the film is draped over the product.

Referring next to FIG. 4, wherein is shown the next step in the operation; the vacuum to the chamber has been shut off and atmosphere is now admitted to the chamber through the passageways 38 and 56. Atmospheric pressure pushes the heated film toward and to the product and to the bottom member 54 so that it, the product, is tightly encapsulated and sealed and with the chamber brought to atmospheric condition the chamber may be opened.

Referring next to FIG. 5, and the final step in the packaging operation, upper chamber 25 has been lifted from engagement with the middle chamber 26 and the packaged product carried by the platen 50 is now ready to be removed therefrom. After the removal of the packaged product 60, the lower chamber 28 and the movable platen 50 are lowered, with the lower chamber 28 and platen 50 brought to the position of FIG. 1 for the repeating of the process above-described.

DESCRIPTION OF THE ALTERNATE EMBODIMENT Referring now to FIGS. 6 through 9, there is shown an alternate chamber construction for the skin packaging of the product in which the apparatus comprises only two chamber portions; however, these chamber portions are arranged slightly different than the embodiment shown in FIGS. 1 through 5.

Referring in particular to FIG. 6, the open chamber includes an upper chamber portion 70 which is maintained in a fixed position by a support not shown. This chamber may be of a substantially rectangular or square shape with a closed top and having a fluid conductor 72 communicating with and extending from the upper portion of this chamber. Movable across the lower open face of this upper chamber 70 is a film 74 similar in purpose and description to the film 48 described in conjunction with the prior apparatus. This film 74 is fed and supported by apparatus not shown and is advanced in a determined manner. A lower chamber 76 is mounted so as to be movable towards and away from the upper chamber 70. Communicating with the interior of the lower chamber portion is a fluid conductor 78 extending downwardly from the lower chamber. Slida'ble in the reduced top opening of the lower chamber portion 76 is a platen 80 carried by rod 82. This platen is movable from the upper opening of the lower chamber portion to the bottom of the chamber portion. Within the lower chamber 76 there are mounted heaters 84 and 85 which are carried near the sides of the chamber and in outward extending portions formed in the sides of the chamber. Deflectors 87 and 88 insure that the heat produced by the heaters 84 and 85 is guided upwardly in the lower chamber. The platen 80 is sized so as to be a sliding fit within the upper portion of the lower chamber 76 and when in the position of FIG. 6, this platen acts as a gate or shutter preventing the flow of heat upwardly. The product 90 is carried on platen 80 which may be water cooled, and upon the top of this platen 80 and supporting the product is a film or tray 91 which has its upward surface adapted for heat sealing to film 74 in the manner described for FIGS. 1 through 5.

It is to be noted that an optional heater means is indicated as mounted in upper housing 70. This heater 75 may be in addition to the heaters 84 and 85 shown in lower housing 76 or this heater 75 may be used instead of the heaters 84 and 85. The particular kind of film and its thickness as well as the product to be packaged all influence the selection of the mode of heating film 74 to a draping condition.

Referring next to FIG. 7, wherein the lower h using 76 has been moved upward into a hermetic sealing engagement with the upper housing 70, the film 74 is disposed between the upper and lower housing and not only is retained and supported but may provide a gasket means to act as a seal to insure that when brought together the upper and lower housing members form a hermetically sealed chamber. At this stage of operation the upper fluid conductor 72 and the lower fluid conductor 78 are opened to a vacuum supply so that both the upper and lower portions of the chamber are brought to a substantially equal reduced pressure. The product 90 and the film or tray 91 upon which it rests has been lowered with the platen 80 resting on the bottom of the chamber. The heat from the heaters 84 and 85 is permitted to pass by the product 90 and by the reflectors 87 and 88. The heat flows upward to engage the underside of the film 74 which is Within the chamber. The heating is continued until the film becomes softened to a drape condition. The film is supported by the sides of the chamber and under conditions of substantially equal reduced pressure on each side of the film is not caused to sag because of a differential in pressure.

The width of the film 74 is merely a matter of selection which is usually dictated by the general size of the product 90 to be packaged. The film is usually wider than the transverse (front to back) interior extent of the chamber so that the film is supported on all sides as it is brought to a drape condition. When the film is of a width Wider than the transverse interior extent of the chamber, it acts as a diaphragm so that in the operation of the chamber the reduced pressures on both sides of the film are maintained at Substantially the same level so that the heated film tends to be maintained in substantially a fiat plane.

Referring next to FIG. 8, it is seen that, with the film softened to a draping condition, the bottom platen is moved upwardly to bring the product into engagement with the softened film 74. The heated film drapes over the product 90 until the edge portions of the film come in contact with the tray or film 91 to partially seal the product 90 between the tray and the film 74. Preferably just before the platform 80 reaches the level of the lower face of the upper chamber 70, the inlet 72 and outlet 78 are shut off from the vacuum.

Referring now to FIG. 9, the operation shown in FIG. 8 has proceeded to where the passageways or outlets 72 and 78 are brought into communication with the atmosphere so that the inner chamber is brought to atmospheric condition. The atmospheric pressure causes the upper film 74 to move inwardly toward the product to tightly enclose the product as well as completing a heat seal of the film 74 to the bottom member 91. After the chambers have been brought to an atmospheric pressure condition, the chamber is opened with the lower housing portion 76 moving again to the position shown in FIG. 6. The product 90, now completely packaged, is now removed from the platform 80 and a new packaging cycle is begun.

vides a heat sealed skin package in which at least one of the members forming the package is a thermoplastic film such as ionomer, polyethylene and the like. This method includes the following steps: placing the product upon a lower packaging member having an upper surface adapted for heat sealing to a thermoplastic film; placing the product and the bottom package member upon a platen movable within a lower housing member, said housing adapted to be brought into engagement with an upper housing member to mate to form a hermetic chamber; moving a thermoplastic film in the way of a lower opening of the upper housing member; moving the housing member portions together to provide a hermetically sealed chamber and with the thermoplastic film disposed in a plane above the product; bringing all hermetically sealed regions of the chamber to a condition of reduced pressure by means of vacuum and the like; providing a source of heat within the chamber so as to warm the film to a softened condition for draping; moving the product and film relative to each other to cause the film to drape over the product while the product and the chamber are in a condition of reduced pressure, the warmed film as it contacts the product being locally cooled by the product so that at the contact area it no longer is heat stretchable; continuing to move the product into the heated film until the outer film portion is brought into engagement with the bottom member to at least partially seal the film to the bottom member; exposing the upper and lower portions of the chamber to atmospheric conditions, the atmospheric pressure pushing the film against the product and against the bottom member absent the use of or presence of pressure bars to effect the final heat seal, and then with the chamber portions now at atmospheric condition, opening the chamber to remove the heat sealed product. I

The resulting packaged product is shown in FIG. 10, wherein product 90 is represented as containing two fowls which are tightly packaged by an upper film 74 heat sealed to a bottom film or tray 91. The portion of tray 91 and film 74 extending beyond the product 90 may be trimmed as desired to suit storing and shipping conditions.

DESCRIPTION OF THE EMBODIMENT OF FIGS. 11-13 Referring next to FIGS. 11, 12 and 13, there is shown automatic or semiautomatic apparatus for packaging the product in a manner similar to that as above-described for FIGS. 1 through 5 and FIGS. 6 through 9. In FIG. 11, a somewhat diagrammatic side .view shows an apparatus in which a bottom transport system includes pairs of sprockets 98 and 99, which sprockets carry a roller chain assembly 100. This chain assembly, which may consist of two or more strands, is adapted to transport a plurality of carriers 102 in an endlessly advancing manner around the sprockets. The sprockets 98 and 99 are preferably rotated intermittently by means not shown so that the carriers are at rest for a determined time and at a determined position and are precisely advanced in response to a predetermined programmed operation. As seen in FIG. 11, the chain 100 is advanced as indicated by the arrows so that on its upper extent the plates 102 are moved from right to left.

In concert with the operation of chain 100 and carriers 102, there is provided at the extreme right upper portion of the apparatus a loading operation. At this loading station there is placed upon these carriers a tray or film portion 104, whichportion provides the bottom part of the package to be hereinafter more fully described. The upper surface of this tray or film portion is adapted for sealing to a thermoplastic film. This film 106 is shown as being fed to the apparatus from the upper right of the apparatus. After the tray 104 has been placed upon the carrier 102 and the carrier advanced, a product 108 is laid upon the tray which, of course, is supported by the carrier 102. Intermittently, this tray-supported product is advanced leftwardly toward the skin packaging operation.

Disposed above the upper extent of the roller chain 100 is the film feeding device and the chamber operation, the film 106 as it is fed is advanced at substantially the same'speed and in synchronism with the conveyor roller chain 100. An upper roller chain arrangement includes sprockets 110, 111 and 112 which carry roller chain 114. There are two pairs of sprockets 110, 111 and 112 with each set of sprockets carrying like extents of roller chain 114. As seen in the side view of FIG. 11, the roller chain 114 on its lower extent is guided downwardly from sprocket 110 to form a downwardly sloped incline and then extends leftwardly on a horizontal extent to sprocket 111. This horizontal deflection is provided by means of either sprockets or guides not shown.

Moving in synchronism with these roller chains 114 are two endless belts 115, each of which belts is carried by means of pulleys 116 and 118. The lower extent of the belts is carried in guides and slides. In this embodiment the pulleys 116 and 118 are spaced further apart than are the lower extent of the guided belts so that the lateral extent of the film 106 as it is brought in the way of the twobelts 115 passes between the be ts at pulleys 116. At a position tangent with sprocket 110, the film is brought in the way of the belt 115 and the chain 114 so as to be retained by the mating of the chain and the belt as the film 106 is advanced. T o the left of sprocket 110 and between the lower extent of chains 114 there is indicated a heat supply 120 which is adapted to heat a local area of the film 106 as it is passed beneath this heating unit. The film is usually heated sutficiently to bring the film toa draping condition. After passing beneath this heating unit the film 106 and trays 104 are brought in the way of an upper chamber generally indicated as 122, said upper chamber being reciprocally moved vertically by means of a pneumatic cylinder 124. This chamber is more completely described hereinafter.

In the chamber position the carrier 102 is moved into Referring next in particular to FIG. 12, it is noted that the carriers generally indicated as 102 are movable toward the stationary plate 126 when they, the carriers, are moved to a position to form a hermetic seal with the upper chamber 122. The carriers are supported by resilently supported guide means to be hereinafter more fully described. Each carrier is advanced by means of like strands of roller chains 100 and are attached to the chains by means of carrier pins 132 and 133. The carrier 102 as shown in this figure is contemplated to have upstanding side portions or walls adapted to form two pockets adapted to receive and retain the trays 104. Attached to and as a part of the stationary plate 126 is a fluid conductor 134, which conductor is preferably connected to a valve source not shown. Still referring to FIG. 12, it is to be noted that the upper chamber 122 includes an upper chamber housing support member 136 having attached thereto downwardly and inwardly extending side portions 138. Mounted interior of and adjacent the upper chamber housing members 136 and selectably extending as desired is a heating unit 140, which heating unit provides such additional heating as may be required for completing a hermetically sealed package by the process to be hereinafter described. The upper chamber 122 is reciprocated by means of the cylinder 124 and is carried by the piston rod 142. This upper chamber member 122 is movable in guide means not shown and movable therewith is a flexible fluid conductor 144. This conductor communicates with the interior of the chamber and is connected by valves to a source of vacuum not shown and t0 the atmosphere.

Referring next to FIG. 13, there is seen in greater tail the preferred construction and arrangement of the carriers 102 and stationary plate 126. A seal between carrier 102 and stationary plate 126 is provided by gasket 146 which is carried by a shoulder extending around the plate. As it is transported to and from in the Way of stationary plate 126, the bottom of the carrier is engaged by slide 148 and may be lifted thereby as it, the carrier, passes over the top of the gasket 146. This slide 148 also provides a bottom cover member to the carrier during the skin packaging operation. The slide 148 is springbiased upwardly by spring 149 so that as carrier 102 is pushed downwardly by the upper chamber as it moves into hermetical sealing position so also is the slide moved downwardly.

The roller chain 100 is supported by a rail 150 which engages and supports the chain roller mounted on carrier pin 132. Rail 150, like slide 148, is also spring-biased upwardly by a plurality of springs 152. The rail and 7 spring are carried by and retained in a support 154. A

engages film 106 and pushes it into a gripping contact with belt 115. A chain guide 156 is formed and positioned so as to engage the chain immediately after the chain 114 leaves sprocket and the guide 156 continues to just before sprocket 111. A belt support and guide 158 engages and carries belt from a sprocket 110 till the belt comes in the way of the carrier 102.

Referring once again to FIGS. 11 and 12, it is noted that a plurality of spaced transverse rods 160 are mounted on and are carried by the chains 114 as they are moved. The transverse rods are spaced so as to engage the lateral extent of film 106 and urge the film toward the plane of belt-s 115. As each carrier approaches the packaging station, the rods are timed so as to engage the film strip 106 adjacent the front and rear edges of the carrier. The upper housing sidewalls 138 are contoured to just miss the rods 160. The underside of the upper housing may have a seal or gasket adapted to accommodate any irregularities in mating surfaces. As particularly seen in FIGS.

12 and 13, passageway 162 communicates with passageway 163 so that the fiuid communication from conductor 134 is extended to the upper surface of carrier 102.

Referring once again to FIG. 11, it 'is to be noted that to 'ithe left of the packaging station chamber there is shown a stripping station in which an upper'frame 164 is carried on a piston rod 165 and is reciprocated by a cylinder not shown: A hot wire trimmer 166 is sized to engage and cut the film at a determined distance from the tray. A pair of pushers 168 is positioned and sized so that each will engage the 'top of the packaged product 130 and when actuated by cylinder 169 pushes the packaged product through bottom openings in the carrier 102. Cylinder 169 and its piston 'rod carries and moves one of the pair of pushers 168. A reciprocable receiving 7 platform 170 is adapted to engage and support package 130. A-cylinder 172 cariies platform 170 on a rod 173. A stop 174 is disposed to engage the platform 170 as it is moved downwardly and as it engages one edge to tilt the platform to a discharge position as shown in phantom outline. W

After the packaged product 130 has been removed from the carrier 102, the scrap film is fed upwardly over roller 129 where it may be ae'cumulatigl on rolls or disposed of by other means not shown. The belt 115, as it moves from the carriers and upwardly to and over pulley 118, is directed or guided sideways or outwardly so as to pass by that film portion 175 of the film 106 that has not become a part of the packagedproduct. This film portion 175 may be reprocessed or otherwise disposed of. The carrier's 102 are carried around sprocket 98 by chain 100 and thence to 'sprocket '99 to bring the carrier again into position for receiving new trays and products for packaging;

It is contemplated that under certain conditions the "carriers 102 may be heated for at least a portion of their cycle of operation. This heating may provide a determined warming of the tray 104 so as to insure the sealing of 'film 106 to the upper surface of'the tray. This warming of the tray may also be localized so as to provide sealing only at selected areas. Also under certain other conditions it is contemplated that carriers 102 may be provided with a means for cooling. i

OPERATIQN OF THE APPARATUS OF FIGS.

: ll, 12 AND 13 V timed relationship to the actuation of the packaging operation and particularly to the movements of the upper chamber 122 and the stripping operation and the pusher y The film 106 may be ionomer, polyethylene or the like 7 and of; one, two or three mil thickness, which film is of a determined width and in this instance is preferably as wide or wider than the carrier 102. The film is transported forwardly and downwardly until it is brought in the way of the chains 114. The belts 115 move inwardly and downwardly from pulleys 116 so that in the region of sprockets 110 they are aligned with the chains 114. In this region, each chain 114. and belt 115 are caused to converge so that as the is brought therebetween the film is gripped and transported forwardly and downwardly at the angle of the chains. The advance of the film continues until it (the comes in the way of the heating element 120, whereby the film is warmed and softened to a draping condition. The chain and belt continue to advance and carry the heat-softened film down and onto the product 108, whereupon as the film contacts the product which is cooler than the film, the film cools locally at those spots where it contacts the product so that it does not stretch much further at the points of conta-c and stays in contact with the product. The transverse reds 160 and the mated chains and belts provide means for retaining the outer portions of the film 106 in a determined plane. The chain guide 156 and belt support 158 provide means so that the film 106 is precisely controlled and guided as the product and the film are trans- ,ported forwardly or leftwardly. The film as it is passed underneath the heating unit continues to be softened until they (the product and film) approach the chamber packaging portion and the mating of the carrier 102, the upper chamber l22 and the stationary plate 126 into a hermetically sealed chamber. 1

Referring particularly to FIG. 12, it is to be noted that as the product :is brought in the way of the upper chamber 122 that the interior heaters direct heat towards those outer portions of the film which are away from the product This interior heating, when required, pro' ides any additional heat necessary to insure that the film not in contact with the product is in or is again brought to a draping condition and that these portions of the film are caused to remain in;a draping and sealing condition. The right portion of FIG. 12 and FIG. 13 shows the upper chamber iri the open position with the film 106 draped over product 108. Chains 114, belts 115 and rods are adapted to retain the outer edges of the film in a plane as the product is moved into'the filmfA longitudinally disposed midbar 176 is adapted to urge the midportion of the film into the common plane of'the outer' edges of the film.

The left portion of FIG. 12 shows the upper chamber member 122 after it has been moved downwardly to provide a hermetic sealed chamber. After sealing, a vacuum is applied to the conductor 144 and to the conductor 134 so that both sides of the chamber are brought simultaneously and substantially to the same reduced pressure condition. As the chamber is opened to vacuum, the product 108 is also brought to a reduced pressure condition so that any air in the voids of the product is generally removed from the product. As the chamber portions on both sides of the film 106 are about the same pressure, the film is caused to remain in its supported condition until the air in the product is removed. The vacuum or reduced pressure on both sides of the film 106 'inay be maintained substantially at the same level and for a determined period of time.

After the determined period of time has elapsed, during which the product has been brought to a condition of'reduced pressure, the vacuum to conductors 144 and 134 is shut off. The valve to the conductor 144 is then opened to the atmosphere just slightly ahead of the valve to the conductor 134 being opened to the atmosphere. The atmosmaining outer portions of the film in the chamber are 7 pushed downward onto the tray 104. the engagement of the film 106 to. the tray 104 the heat sealing of the packaged product is completed. This heat sealing of the film to the tray is accomplished without the use of or requirement of a sealing bar. The atmospheric pressure also causes the film to be tightly pressed around the product 108. After the upper and lower portion of the chamber has been orought to atmospheric pressure, the upper chamber 122 is moved upwardly, carrier 102 is biased upwardly from supportplate 126 and thechain 100' is ad vanced leftwardly one station or position so that the above process may be repeated. This intermittent feeding c0n tinues to the stripping station where the packaged product 130 is cut from the strip and is discharged.

At the stripping station the hot wire trimmer is moved downwardly to sever the film adjacent the tray 104. The pusher 168 is moved downwardly to push the tray through 13 the opening in the carrier 102. Platform 170 engages the bottom of the tray and transports the packaged product downwardly until the platform engages stop 174 and is tilted to a discharge condition.

METHOD OF PACKAGING AS EXEMPLIFIED IN FIGS. 11, 12 AND 13 The method of packaging as shown in the automatic apparatus of FIGS. 11, 12 and 13 includes the following steps: placing a tray upon a carrier; placing a product upon said tray with the upwardly disposed surface of the tray adapted to make a heat-seal with a thermoplastic film; advancing the carrier until the carrier is brought in the way of an upper chamber member; advancing a strip of thermoplastic film in the way of a heating unit to heat the film until the film is brought to a draping condition; moving the heated film in the way of the product so that the film is in part draped over the product and as the film contacts the product the film is cooled so that the draping condition is locally stopped; advancing the product with its partially draped film laying thereon into the way of said upper chamber; moving the upper chamber downwardly to form a hermetic seal with the carrier and to retain the film therebetween, the product being partially draped with the film; when necessary, heating that portion of the film between the chamber side and the product by internal heating means to retain or bring the film portion exterior of the product and within the chamber into a draped condition; bringing the upper and lower portions of the chamber on each side of the film into a condition of reduced pressure by means of a vacuum and the like and so that air in and about the product is removed therefrom; shutting ofi the vacuum to the upper and lower chamber portions; admitting atmosphere to the upper portion of the chamber so that the atmospheric pressure causes the portion of film in draped condition to be moved into tight engagement with the product and to be moved downwardly into heat-sealing contact with the bottom film portion; bringing the complete chamber into atmospheric condition so that the chamber may be opened;

opening the chamber; transporting the packaged product on the carrier from the chamber position so that the completely packaged product may be removed from the carrier, and delivering the packaged product to other operations such as trimming and the like.

DESCRIPTION OF THE EMBODIMENT OF FIGS. 14 AND 15 Referring next to the apparatus of FIGS. 14 and 15,

there is shown a modification of the automatic and semiautomatic apparatus of FIGS. 11-13 above-described. In FIG. 14, a somewhat diagrammatic side view shows an apparatus in which a bottom transport system includes a bottom roller conveyor support table 180. This roller vided a package receiving guide 186 into which the product 108 is located in timed and spaced position on the film 184. The lower film and product move leftwardly in the direction of the arrows upon the rollers of the conveyor 180 until the product 108 comes in the way of the 7 upper film 106 which is fed to the packaging station in the manner shown and described in FIG. 11 above.

The roller chain 114, belt 115, chain guide 156 and belt support 158 are arranged as described in FIG. 11 above with the film 106 being brought in the way of the strip heater 120 as above-described. Transverse rods 160 are similarly attached to roller chain 114 as above-described and provide means for transverse retaining of the film 14 106 in a determined plane similar to the manner described in FIG. 11. However, it is to be noted that the bottom film 184 is flat rather than having upwardly extending sides as in the trays above-described. For this reason the film 106 in this apparatus is brought closer to the final seal line than it is in the apparatus of FIG. 11.

After the product 108 and lower film 184 reach the slide support 182, the lower film and product are caused to be pulled into a determined position below the upper chamber 122. This upper chamber is identical or similar to the chamber described in conjunction with FIG. 11; however, in certain applications it may be desirable to extend the side walls 138 a small amount downwardly to provide an additional height necessary to accommodate the absence of a carrier 102 as used in the apparatus of FIG. 11.

Referring now in particular to FIG. 15, it is to be noted that lower film 184 is of a lesser extent than the transverse distance of the side wall 138 and that instead of a single fluid conductor there are a pair of fluid conductors which are connected to a flow conducting means formed in the slide support 182 so as to communicate with that portion of the chamber which is outside the bottom film 184. It is to be noted that belt is carried in a slide guide 188 and that upper film 106 is retained between the belt 115 and the chain 114 by means of chain guide 156 in the manner above-described. After completing the the packaging of the product there is an idle station whereby the package seals are allowed to cool, thence the packaged product is fed to the trimming station which is similar to the station described in FIG. 11; however, it is to be noted that the bottom platform is a sliding fit in the aperture formed in the slide support 182. This platform 170 is movable in time with the movement of the pusher 168 and after the hot wire trimming has been completed in the manner above-described. After the product has been trimmed from the package strip, the scrap film 190, which contains both upper and lower film portions not used to form or provide a part of the package, is accumulated as scrap for reprocessing or f other disposition.

USE AND OPERATION OF THE APPARATUS vOF FIGS. 14 AND 15 The apparatus of FIGS. 14 and 15 operates in a manner similar to the manner of the apparatus of FIGS. 11 through 13; however, it is to be noted that film 184 which provides the bottom portion of the product package is a continuous strip and is brought in the way of the roller conveyor which may have free rolling rollers or may be powered as required so that the lower film is advanced in a determined manner. The lower film is advanced 'to coincide with the advancement of the film 106 and is moved in a timed manner to the packaging operation to be more fully described hereinafter. The packaged product, after the packaging operation is finished, is moved to the trimming operation and is removed from the strip and discharged in the same manner as described in the apparatus of FIGS. 1ll3. With the exception that the film 184 is lower than the upper portion of the tray carrier 102 and that the tray carrier is movable by chains, the operation of the two apparatus are quite similar. The operational differences of the two, and the sequence of packaging is to be more fully described in conjunction with the process steps shown in FIGS. 16 through 18 and FIGS. 19 through 21.

PACKAGING SEQUENCE SHOWN IN FIGS. 16, 17 AND 18 Referring particularly to FIGS. 16, 17 and 18, the sequence of packaging is diagrammatically shown in the sectional views wherein is illustrated the steps of forming the package. In FIG. 16, it is to be noted that the upper housing 122 is in position above the carrier 102 and that 102 is spring-biased above the support plate 126.

The heated film 106 extends from the outer edge of the carrier 102 thence over the product 108 and thence, as held by the midbars 176, is directed downwardly towards the middle portion of the carrier 102. At this particular stage the portion of film in contact with product 108 has lost its draping ability as it is contemplated that product 108 is comparatively cool or cold when placed upon the tray 104.

Referring next to FIG. 17, it is to be noted that the upper housing 122 has now been moved downwardly to push the outer edges of the film into a determined plane and to trap the film against the carrier 102. The chamber thus formed is now in a hermetically sealed condition. Fluid conductor 144 and fluid conductor 134 are open to the vacuum in the manner above-described so that both sides of the film 106 are exposed to a similar condition of reduced pressure. The product 108 is also subject to vacuum or reduced pressure so that any voids therein are brought to a like condition of reduced pressure. A heater 140 may be employed to supply a source of heat directed towards the portion of film 106 that is not in contact with the product 108 or retained by the housing so that this tent-like slope portion is brought to or is maintained in a draping condition.

Referring next to FIG. 18, the vacuum supply to fluid conductors 134 and 144 is shut off and the first conductor 144 is open to the atmosphere so that atmospheric pressure enters the upper portion of the chamber to cause the film 106 to be pushed tightly to and against the product 108 and down into the upper surface of the tray 104. After this action has been started, the bottom conductor 134 is opened to the atmosphere so that when the chamber is brought to atmospheric pressure the chamber may be opened and the bottom carrier is then advanced to later operations above-described.

PACKAGING SEQUENCE SHOWN IN FIGS. 19, AND 21 Referring next to FIGS. 19, 20 and 21, and this sequence of packaging, it is to be noted that instead of carrier 102, the bottom film 184 rests upon the slide support 182 and in the manner of FIG. 16, the film 106 that is not in engagement with the product 108 is in a draping condition and lays at a downward slope around each of the products 108.

Referring next to FIG. 20, it is to be noted that the upper chamber 122 has been moved downwardly to clamp the film portion between the side wall 138 and the slide support 182 to form a hermetically sealed chamber. A gasket around the side wall 138 may provide the proper resilience necessary to accommodate any irregularities between the side wall 138 and the upper surface of slide support 182. Although this sealing is always between the same mating parts, small irregularities may be readily corrected at assembly or during use. After the hermetic seal has been made, the upper portion and lower portions of the chamber as provided by fluid conductors 144, 186 and 187 are open to vacuum so that the chamber is brought to a condition of reduced pressure in the manner of FIG. 17 above. The product 108 is also brought to a condition of reduced pressure so that any voids therein may have the air generally removed.

Referring now to the chamber of FIG. 21, the vacuum to the conductors 144, 186 and 187 has been shut off and atmospheric pressure through conductor 144 is first allowed to enter the chamber to cause the film 106 to be moved against the product 108 and intosealing contact with the upper surface of the bottom film 184. After a determined interval of time the fluid conductors 186 and 187 are also open to atmospheric pressure so that the upper housing 122 may be lifted from in the way of the packaged product. The packaged product and the film 184 are then advanced from the chamber for trimming or other operations in the manner above-described.

It is to be noted that in the methods shown in FIGS.

16-18 and FIGS. 19-21, that the internal heat within the upper chamber 122 may not be necessary when the heater brings the film to a draping condition and the skin packaging sequence is sufliciently rapid to complete the packaging before the warmed film cools to a non-heat sealing condition. It is to be further noted that although the apparatus of FIGS. 11 and 14 are preferably cycled in an intermittent manner, the apparatus can be modified to provide continuous operation.

DEFINITIONS In the foregoing description the term film is applied to a thin non-fibrous flexible sheet of less than tenthousandths of an inch in thickness. Ionomer resin film (such as Surlyn A a product of E. I. du Pont) has been found excellent in the packaging process abovedescribed. These films are not impervious to the passage of oxygen but permit a tight package to be made and any initial negative pressure interior of the package may be lost gradually over a period of several days or more. Both the upper film and the bottom package member are contemplated to be sufiiciently impervious to the passage of air to enable the above process to be eflectively completed.

Terms such as in, out, up, down, right, left and the like are applied to the various embodiments of packaging apparatus as shown and described in conjunction with the drawings. These terms are used merely for the purposes of description and do not necessarily apply to a particular position in which the apparatus may be constructed or used.

The conception of the above-described packaging apparatus and the method of packaging and their many applications are not limited to the embodiments above-described but departures therefrom may be made within the scope of the accompanying claims and protection is sought to the broadest extent the prior act allows.

What is claimed is:

1. A method of skin packaging products which may be of unlike and irregular shape, and in which the skin packaging is done in the presence of a vacuum and in which at least one of the members forming the skin package is a thermoplastic film, said steps of skin packaging including: (a) placing the product to be packaged upon a' lower packaging member having an upper surface adapted for heat sealing to a thermoplastic film; (b) bringing the product and the bottom package member to and within a lower housing member adapted to be brought into engagement with an upper housing member to mate with and form a hermetically sealed chamber; (0) moving an upper thermoplastic film in the way of a lower opening of the upper housing member; ((1) moving at least one of the housing member portions toward the other to provide a hermetically sealed chamber and with the supported portions of the thermoplastic film disposed in a plane above the lower package member; (e) bringing all hermetically sealed regions of the chamber to a condition of reduced pressure by means of vacuum and the like; (f) providing a source of heat adapted to warm the upper thermoplastic film to a softened condition for draping; (g) moving the product and the film relative to each other to cause the film to drape over the product until the film contacts the product and is locally cooled by the product to stop stretching of the film at such contacted portions; (h) moving the product into the heated film until the outer portion of the heated film is brought near to the bottom member; (i) shutting ofi? the vacuum to the chamber then exposing first the upper then the lower portions of the chamber to atmospheric conditions, the atmospheric pressure in the upper portion of the chamber pushing the film against the product and against the bottom member absent the use of pressure bars, and (j) opening the chamber to remove the heat sealed skin packaged product.

2. A method of skin packaging as in claim 1 in which 1 7 there is a platen movable within the lower housing member, this platen adapted to be brought to the upper housing member to bring the lower packaging member near to the upper film member.

3. A method of skin packaging as in claim 2 in which the source of heat is a heating element within the chamber and said element is adapted to warm the upper thermoplastic film while the chamber is closed in a hermetically sealed condition.

4. A method of skin packaging as in claim 3 in which the source of heat is carried in the upper chamber and the heating source is movable to and away from a position adjacent the upper thermoplastic film.

5. A method of skin packaging as in claim 3 in which the source of heat is carried in the lower chamber, the source being adapted to warm the film to a draping condition when the platen is moved to a low position within the lower housing portion of the chamber, and the source of heat being closed to the film when the platen is in a product loading and unloading position.

6. A method of skin packaging as in claim 1 in which the bringing of the product to the position beneath the upper housing member is a carrier adapted to be a part of the lower housing member, and in which the upper thermoplastic film is brought in the way of a heating means prior to the film being brought in the way of the upper chamber member.

7. A method of skin packaging as in claim 6 in which there may be provided an additional heating means within the upper housing so the film portion within the upper chamber is brought to a draping condition, and in which the carrier is adapted to carry at least one tray.

8. A method of skin packaging as in claim 7 in which the carrier is movable to a trimming operation wherein the skin Packaged product is cut from the upper thermoplastic film strip and is discharged from the carrier.

9. A method of skin packaging as in claim 8 in which the skin packaged product is pushed through an opening in the carrier and is received from the carrier and is transported to a discharge position by a movable platform from whence the skin packaged product is moved to an accumulating station.

10. A method of skin packaging as in claim 6 in which the upper thermoplastic film is fed toward the carrier path from a supply station, and intermediate the feeding station and convergence with the carrier the film is brought in the way of a film engaging and transporting means.

11. A method of skin packaging as in claim 10* in which the film engaging and transporting means includes an endless chain and an endless belt adapted to be brought together and between the chain and belt the film is gripped.

12. A method of skin packaging as in claim 11 in which the film in the chamber closed position is supported and retained by engaging portions of the upper and lower chamber.

13. A method of skin packaging as in claim 1 in which the lower packaging member is a strip of film and in bringing of the product to a position beneath the upper housing member is carried on a conveyor section adapted to receive and transport the lower film for a determined distance, and in which the lower chamber portion is a portion of a slide support plate upon which the loWer film and spaced product is advanced and supported.

14. A method of skin packaging as in claim 13 in which the skin packaged product is moved from the packaging operation to a trimming operation whereat the packaged product is cut from the strip of film and is discharged from the path of the film.

15. A method of skin packaging as in claim 14 in which the motion of the upper and lower films is in synchronism and in which the motion is intermittent.

16. A method of skin packaging as in claim 13 in which the upper thermoplastic film is brought in the way of a heating means prior to the film being brought in the way of the upper chamber member, and in which there may be provided additional heating means within the upper housing so that the film portion within the upper chamber may be brought to a draping condition.

17. A skin packaging apparatus which may be for unlike products of irregular shape and in which the package is formed in the presence of a vacuum, the package so formed having an upper packaging member which is a thermoplastic film and with the lower packaging member an impervious portion having at least a portion of its product supporting surface adapted for pressure sealing to the heated upper film, said skin packaging apparatus including: (a) an upper chamber portion having a downwardly extending opening; (b) a lower chamber portion having an opening adapted to mate with the upper chamber downwardly extending opening and when engaged to form a hermetically sealed chamber; (c) means to move at least one of said upper and lower chamber portions toward and away from the other chamber portion to bring the chamber portions to a closed position to form a hermetically sealed chamber and to an open position whereby the chamber may be loaded and unloaded; (d) a fluid conducting means for communicating with the upper chamber and connected to means for cycling the upper chamber from a condition of atmospheric pressure to a condition of reduced pressure; (e) a fluid conducting means for communicating with the lower chamber and connected to means for cycling the lower chamber from a condition of atmospheric pressure to a condition of reduced pressure; (f) means for feeding a strip of thermoplastic film in the Way of the chamber openings to provide an upper package member which film, when the upper and lower chamber portions are brought together, is held at those portions which are in contact with the engaged chamber openings; (g) means for heating the upper film to warm the film to a draping condition; (h) means for feeding a lower packaging member to the chamber posi tion; (i) means for providing a package support for the lower package member; (j) means for advancing the supported product to and into the draped heated film; (k) means for bringing the hermetically sealed chamber portions on both sides of the upper film to a substantially simultaneous and equal condition of reduced pressure for a selected period of time; (1) means for bringing the hermetically sealed upper chamber portion of reduced pressure to a condition of atmospheric pressure, and (m) means for bringing the hermetically sealed lower chamber portion of reduced pressure to a condition of atmospheric pressure after beginning to bring the upper chamber to a condition of atmospheric pressure.

18. A skin packaging apparatus as in claim 17 in which there is provided a bottom platen movable within the bottom chamber portion, the bottom platen movable from a position substantially at the bottom of the chamber to an upper position substantially at the level of the plane at which the upper film is held and means for moving the bottom platen from its bottom position in the chamber to its upper determined position.

19. A skin package apparatus as in claim 18 in which there is provided a middle housing member portion pro- Viding an upper fixed portion of the lower housing member and in which there is a movable lower housing member portion adapted to move to and away from the middle housing member portion so that when the lower housing member portion is in a lower position a ready access to the movable bottom platen is provided.

20. A skin package apparatus as in claim 19 in which there is carried a heating element within the chamber and when the chamber is closed and during the hermetically sealed period of reduced pressure, the heating element may be actuated to heat the upper thermoplastic film to a draping condition; and there is means for regulating the period of heating time of the heating element.

21. A skin packaging apparatus as in claim 20 in which the heating elements are carried in the upper chamber portion.

22. A skin packaging apparatus as in claim 20 in which the heating elements are carried in the fixed middle housing member portion;

23. A skin packaging apparatus as in claim 20 in which the heating elements are carried in the upper chamber portion and in the fixed middle housing member portion. Z l

24. A skin packaging apparatus asin claim 18 in which the heating element is carried in the bottom housing member and in which the bottom platen is sized and positioned so as to substantially close the opengend of the bottom housing member when the platen is brought to the upper open end of the lower housing and in which the heating element is positioned so that when the bottom platen is brought to the lower position the heating element exposed to permit heat to be directed toward the upper film. g e

25. A skin packaging apparatus as in claim 24 in which the piaten is adapted for warming at least portions of the lower packaging member to assist the heat sealing of the upper film member to the lower packaging member.

26. A skin packaging apparatus as in claim 18 it; which the heating element is carried in the upper housing and may be selectively actuated to heat the upper filrn to a draping condition and in which there is provided means for regulating the period of heating time.

27. A skin packaging apparatus as in claim 18 in which there are heating elements carried in both the upper and lower housing portions and in which there are provided means whereby said heating elements may be actuated to heat the upper film: to a draping condition and there is provided means for regulating the period of heating time of the heating elements.

28. A skin packaging apparatus as in claim 17 in which there are additionally provided a plurality of carriers arranged to be.;mved sequentially to and in the way of the. upper housing member, and after the package sealing operation is completed, the carriers are moved from in the way of the upper housing; in which there is provided means for supporting ,the carriers and to form a lower housing when the carriers are positioned beneath the upper housing member; and in which the upper film is brought to and gripped bg means of a film transport apparatus so that the film and carriers may be moved in a precise synchronism.

29. A skin packaging apparatus as in claim 28 in which eachtcarrier is adapted to receive and transport at ieast one tray and the product to be'packaged as placed thereon; and there is provided an opening in the carrier through which the packaged product may be pushed.

30. A skin packaging apparatus as in claim 29 in which there is provided means for heating the film before *the film is brought in the way of the upper chamber; and in which there may be provided additional heating means within the upper chamber and means for cycling 'said heating means in the upper chamber.

31. A skin packaging apparatus as in claim 30 in which there is provided means for warming the carrier so as to warm at least portions of the lower packaging member to assist the heat sealing of the upper film member to the lower packaging member.

32. A skin packaging apparatus as in claim 30 in Whichthe carriers are adapted to be moved t6 bring the packaged product to a trimming apparatus whereby the packaged'product and the'tray are trimmed from the film and means is provided for pushing the trimmed packaged product thfough anjopening provided in the" carrier.

33. A skin packaging apparatus as in claim 32 in which the carriers are equally spaced and are mounted on at least one endless roller chain; and in which the film transport includes a pair of endless roller chains and a pair of endless beltsQthe chains and pelts being adapted for movi g at t e-i ms speed as the pe 9 the carriers and for a "determined portion of their travel the film roller chains are adapted to be brought adjacent the endless belts so that the upper film is engaged and gripped between said chains and belts.

34. A skin packaging apparatus as in claim 33: in which the film transport .roller chains inciude a plurality of transverse rods attached to and extending rom one roller chain to the other roller .phain, the rods spaced and timed to approach and move forwardly adjacent one of the carriers of the product transporting system;

35. A skin packaging apparatus as in claim 17 in which the lower packaging member is from a strip of film and in which there is provided a conveyor support section adapted to receive and support the lower packaging member asgit is advanced toward the package forming station; and in which there is a slide support member adapted to receive the film from the conveyor support section and to further support the advancing film and product and to form the lower chamber member portion as the packaging operation is performed. e

36. A skin packaging apparatus as in'claim 35 in which there is provided a subsequent trimming station adapted to engage receiving means in the slide support member, the trimming stationiincluding means for cutting the packaged produet from the strip of film and there is provided a means for receiving and discharging the product from in the path of the film as it is moved on the slide suppprt member. a

37. A skin packaging apparatus as in claim 36 in which the trimming apparatus includes a hot wire trimmer and means is provided for moving the hot wire trimmer to and through the film to sever the packaged product from the film.

38. A skin packaging apparatus as in claim 37 in which the trimming apparatus includes a movable platform adapted to support the skin paekaged product as it is trimmed and to transport and discharge the skin packaged product from in the path of the film.

39. A method of packaging including the steps of: placing a product to be packaged upon a lower packaging member having an upper surface adapted for heat sealing to an upper thermoplastic film; heating the film to a softened condition for draping; moving the product and the' film relative to each other e to cause the film to drape over the product; bringing each side of the film to a condition to substantially equal reduced pressure by means of vacuum 2 to remove air from between the film and the packaging member while preventing premature sealing of the film to the packaging membgr; and, pushing the film against the product and against the packaging member to form a heat sealed skin packaged product. 7 Z 40. The method of packaging of claim 39 wherein each side of the film is brought to the condition of substantially equal pressure after the film is draped over the product. 7

41. The method of packaging of claim 39 wherein each side of the film is brought to the condition of substantiatly equal pressure before the film is draped over the product. 7 i

42. The method of packaging of claim 39 including the step of further heating the film prior to pushing the film against the product and against the packaging member, 43; A method of packaging including the steps of: placing a product to be packaged upon a lower pack- 7 aging member having an upper surface adapted for 'heat sealing to an uppeu thermoplastic film; bringing the product and the lower packaging member to a lower chamber portion adapted to he brought into engagemeut with an upper chamber portion to J mate with and'form a hermetically sealed chamber; moving the upper thermoplastic film in the way of a lower opening of the upper chamber portion; p oviding a sourc of h at ada ted to warm the upper thermoplastic film to a softened condition for drapmoving the product and the heated film relative to each other to cause the film to drape over the product until the film contacts the product and is locally cooled by the product to stop stretching of the film at such contacted portions;

moving at least one of the chamber portions toward the other to provide a hermetically sealed chamber and with the supported portions of the thermoplastic film disposed in a plane above the lower packaging member;

bringing the upper and lower chamber portions of the chamber to a condition of substantially equal reduced pressure by means of vacuum;

shutting ofi the vacuum to the chamber;

exposing first the upper and then the lower chamber portions to atmospheric conditions, the atmospheric pressure in the upper portion of the chamber pushing the film against the product and against the bottom packaging member to seal the film to the packaging member; and,

opening the chamber to remove the heat sealed skin packaged product.

44. A packaging apparatus including:

an upper chamber portion;

a lower chamber portion;

means to bring the upper and lower chamber portions to a closed position to form a hermetically sealed chamber;

means for feeding a strip of thermoplastic film in the way of the chamber portions to provide an upper film, which when the upper and lower chamber portions are brought together, is gripped between those portions which are in contact;

means for heating the upper film to warm the film to a draping condition;

means for feeding a lower packaging member to the chamber portions;

means for providing a support for the lower packaging member and product;

means for moving the supported product to and into the heated film;

means for bringing the upper and lower chamber portions from a condition of atmospheric pressure to a condition of reduced pressure;

means for bringing the upper and lower chamber portions on both sides of the upper film to a substantially simultaneous and equal condition of reduced pressure for a selected period of time;

means for bringing the upper chamber portion from reduced pressure to a condition of atmospheric pressure; and,

means for bringing the lower chamber portion from reduced pressure to a condition of atmospheric pressure.

References Cited UNITED STATES PATENTS 3,267,634 8/1966 Omori 5322 FOREIGN PATENTS 245,774 7/ 1963 Australia.

TRAVIS S. MCGEHEE, Primary Examiner

Images