US2785519A - Heat shrinking apparatus - Google Patents

Description

March 19, 1957 H RUMSEY, JR

HEAT SHRINKING APPARATUS Filed Sept. 24, 1953 4 Sheets-Sneet 1 7 7 fw q Mn T M MR A W March 19, 1957 H. RUMSEY, JR 2,785,519

HEAT SHRINKING APPARATUS Filed Sept. 24, 1953 4 Sheets-Sneet 2 INVENTOR .lfeggbGW! fr'umsg Jh ATTORNEYS March Filed Sept. 24, 1955 H. RUMSEY, JR

HEAT SHRINKING APPARATUS 4 Sheets-Sneet 3 INVENTOR ffer'bezg Ramsgy r.

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ATTORNEYS March 19, 1957 H. RUMSEY, JR

HEAT SHRINKING APPARATUS 4 Sheets-Sneet 4 Filed Sept. 24 1953 INVENTOB Rumse JfQWZJQ/ i ATTORNEYS United States Patent O i HEAT SHRIN KING APPARATUS Herbert Rumsey, Jr., Rochester, N. Y., assignor t Glaz- Wrap Packaging Co., Passaic, N. J., a corporation of New Jersey Application September 24, 1953, Serial No. 382,174

6 Claims. (Cl. 53-134) This invention relates to improved heat shrinking apparatus to be used in shrinking sheet wrapping material around a package to present a smooth, unwrinkled, attractive appearance.

In moder'n merchandising, it is important that products be attractively packaged and presented to the public. In this connection, it is frequently advantageous to wrap a transparent sheet material around at least a portion of the package so that the food product is displayed therethrough. Where this type of packagin is employed the transparentv wrapping material should be smooth and tightly stretched so as to present an attractive appearance. Several types of wrapping materials can be shrunk when subjected to heat. As an example, tensiled or oriented rubber hydrochloride available commercially under the trade name Pliofilm and tensiled or oriented polyvinyl chloride available commercially under the trade name Saran. When this type of wrapping material is employed it can be wrapped rather loosely around the package and thereafter subjected to a predetermined temperature so as to cause it to shrink and thereby present a smooth, unwrinkled, attractive appearance.

I have employed a heated flat plate to accomplish the shrinkage of the wrapping material and while this method is reasonably satisfactory it is sometimes diflicult to apply uniform heat to all areas of the wrapping material.

In addition, there is the problem of maintaining a constant ideal temperature since too high a temperature melts the film and too low a temperature does not provide sufficient shrinkage. l have found that by subjecting the wrapping material to a hot fluid, particularly hot water, uniform controlled temperature can readily be applied to all portions of the wrapping material with the result that uniform maximum shrinkage, without melting or fusing of the wrapping material, is obtained. In many instances, it is possible to submerge the entire package in hot water of the required temperature. In other instances it is not possible to thus submerge the package in water since areas of the package must be kept dry for the application of a label or for sealing purposes or because of the danger of seepage of water into the package.

It is an object of the present invention to provide improved apparatus for causing the heat shrinking of wrapping material around a package by the application of a heated fluid, particularly hot water, to controlled areas of the package without submerging the package in the fluid.

A further object of the invention is the provision of improved apparatus of the above character which may be utilized for applying labels and also for heat sealing the package.

Other objects of the invention include the provision of improved apparatus for heat shrinking wrapping materials which is of relatively simple and inexpensive construction; which is flexible in design so that it can be utilized in connection with packages of various shapes;

which is flexible in use or application so that it may be readily used either for heat shrinking alone or for .the application of lables or for the heat sealing of a package; which is simple to operate so that it can be readily used by unskilled operators; and which is sturdy in construction so that it can be used over a long period of time with a minimum amount of repairs.

In the accompanying drawing Fig. l is a side elevational view of apparatus embodying my invention showing the apparatus as used for heat shrinking a relatively flat type of package;

Fig. 2 is a top plan view of the apparatus shown in Fig. 1;

Fig. 3 is a partially sectional and partially side elevational view of the apparatus showing it as arranged for a relatively thicker package;

Fig. 4 is a top plan view with portions broken away and omitted of the apparatus as shown in Fig. 3;

Fig. 5 is a sectional view in the direction of the arrows on the line 5-5 of Fig. 2;

Fig. 6 is a similar sectional view in the direction of the arrows on the line 6-6 of Fig. 4;

Fig. 7 is a detailed, sectional view through the rollers and package on the line 7-7 of Fig. 6;

Fig. 8 is a detailed view of the apparatus for controlling the spring tension of the rollers;

Fig. 9 is a detailed view in perspective of the feeding and receiving platform which may be used in the form of apparatus shown in Figs. 3 and 4;

Fig. 10 is a top plan view of the tank for the heated fluid;

Fig. 11 is a detailed view in elevation showing the type of mechanism that may be employed for maintaining the fluid in the tank at a constant level;

Fig. 12 is a perspective view of a representative type of flat package with which my apparatus may be used for shrinking and wrapping material; and

Fig. 13 is a perspective view of a representative type of relatively thicker package together with a sealing label with which my apparatus may be used both for shrinking the wrapper and for applying the label.

Referring now to the basic construction of my machine, whether it is assembled in the form shown in Figs. 1 or 2, or the form shown in Figs. 3 or 4 it will be seen that it comprises a base member or support 15 on which is mounted the tank 16 for holding the hot water, or other heated fluid.

The tank is shown most clearly in Figs. 11, 2, 3, 4 and 10 and is preferably rectangular in shape and provided with an open top of a size to accommodate the fluid applying roller. The tank rests directly on the supporting base 15 and is adjustably mounted thereon by means of wing nuts engaging the slotted brackets 17. By loosening the wing nuts the tank may be shifted forwardly or rearwardly to obtain the desired relationship between the fluid applying roller and the pressure roller.

Inside the tank is an electric heating element 18 which should be of the type that operates satisfactorily when immersed in water or other fluids. For this purpose heating elements of the type available commercially under the trade name Calrod operate very satisfactorily. The heating element is connected by leads 19 to a suitable source of electric current so as to maintain the water at the desired temperature. I have found that the water when applied to tensilized rubber hydrochloride or tensilized polyvinyl chloride should preferably be at a temperature between and to the boiling point of water.

Suitable means such as the pivoted tube 20 extend outwardly through the side wall of the tank and which may be pivoted between vertical positions and horizontal positions should be provided for draining the tank. When a the tube is'in vertical position the water in the tank can be maintained at the" proper level. downwardly to horizontal position the tank may be drained.

Suitable filling mechani-sm preferably of the typeto automatically maintain the liquid at its desired level is also provided such as shown in Fig. 11. This preferably takes the form of an enclosed container 21 having a valve controlledinlet at its upper end and an outlet spout 23 dependingdownwardly into the tank. at its lower end.

The container 21 is supported by a suitable bracket 24 above tank 16 with the. spoutextending into the tank to the desired level of the water. Container 21Lis. filled with water through valve 22 anclthe. valve is then closed. Water from container 21 will flow into tank lfiuuntilthe lower end of spout 23 is immersed in the water. Due to the factthat container 21 is completely closed and air can only enter into the container through the spout 23, no" further'wate'r will flow'from the spout when its lower end is immersed in the water in the tank. The container 21 is filled fromtime to time through valve 22 but the valve is normallymaintained in closed position.

The two ends of tank 16 are provided with upwardly projecting brackets '25 which are slotted in the manner shown for receiving the bearings 26 of shaft 27jsupporting the aluminurncylinder 28. The cylinder 28 and shaft 27 are free to rotate in the bearings 26'.

An adjustable, variable speed pulley 29 is mounted on 'one end of shaft 27 and is connected by a belt 30 to a motor or. other drive unit (not shown). The pulley 29 is of a well-known variable speed type in which the diameter may be readily varied by shifting the two sides of the pulley towards and away from each other. In this way, the speed of rotation of shaft 27 may be increased or decreased.

The cylinder 23 serves as a support for the water applying roller and rollers of various types may be applied By pivoting the tube in accordance with the type of package being used with the machine. In Figs. 1, 2, 5 and 7, I have shown a cylindrical roller 31 which is suitable for use in connection with a relatively flat, thin package such as a package of bacon. The roller 31 extends for almost the entire length of cylinder 28 and inthe form of a tubular sleeve embracing the cylinder and having a bayonet slot 32 for engaging a screw secured to cylinder 28 and which serves to releasably hold the roller in place. The roller may be made of any desired material which will withstand the hot water in which it is partially immersed. Thus, it may have a relatively hard, smooth surface. However, '1 prefer'to provide the roller with a covering 33ofyiel din'g, water absorbing material and for this purpose I have found that plastic sponge or synthetic rubber sponge serves very satisfactorily. The diameter of the cylinder 28 and roller 31 are such that when the parts are assembled as shown, the lowcr portion of the roller will be immersed in the water in tank 16 while the upper part of the roller is disposed above the tank in the atmosphere. By withdrawing one of the bearings 26 and the end of the shaft 27 from supporting bracket 25, roller 31 maybe readily assembled with, or removed from the cylinder .28.

As previously indicated, various types of rollers may be assembled with cylinderlh in accordance with the type of package to be processed by the machine. In Figs. 3, 4, and 6 I have shown a modified roller 34 which is part-ic'ularly suitable for use in connection with relatively thick, flat packages, wherein it is desirable to apply heat to-the sides of the package as well as to the display surface thereof in order to obtain the proper shrinkage of the wrapping material. Roller 34 takes the form of a tubular sleeve which fits snugly over cylinder 28 and is similarly provided witlra bayonet slot 35 for holding it in place on the cylinder. Extending around one portion of the roller is a covering 36 which likewise is preferably made of a thetic rubber sponge. Adjacent the two ends of the covering 36 I provide flanges 37 having their confronting faces lined with similar yielding absorbing material; When the roller 34 is rotated in tank 16 absorbent covering 36 as well as the absorbent surface of the flanges 37 will pick up water from the tank and, as will be later described, will apply it to the sides as well as the display face of the package.

Cooperating with fluid applyingroller31 or 34, as the case may be, is a heated pressure roller which serves to press the package against the fluid applying. roller towin: sure the application of the heatedfluid'tothe package. and also to expel any confined air from the package. Due to the fact that the pressure roller is heated,, -it,.serves to help maintain the base of the package in dry condition. In addition, the heated pressure roller may be utilized for applying a label to a package and also for heat-sealing the package.

The pressure roller assembly comprises. a. tubular shaft 38 journaled in the bracket 3:9. The bracketis formed in two separable parts connected together. by, the bolt and wing nut 49 so that the two parts may be readily separated to permit a roller to be assembled withor removed from the shaft 38. The bracket 39 is carried by a pairofarrns 41 which, in turn, are pivotally mounted at 42 on the standards 43. The pressure roller. is provided. with adjustable means for maintaining it inspaced relationship with respect to the fluid applying roller and this maytake the form of screw 44, for each of the arms, 41, adjustably threaded to bracket 45 so as to be engageable with platform 46 mounted on a standard 47. By turning .the1screw 44 in a clockwise direction, the pressure roller .is spaced a greater distance from the fluid applying roller and, ,QOntrarywise, by turning the screw in an anti-clockwise, direction, the pressure roller approaches closer to the fluid applying roller.

A spring 48, connected between bracket 45 and stand-' ard 47, normally serves to urge the pressure. roller tQ- wards the fluid applying roller under yielding spring force. The spring tension may be adjusted by connecting it to any one of a number of apertures in standard 47.

It will be appreciated that the normal spacing between the rollers is varied in accordance with the. size. of. the package being processed. The spacing between therollers should be slightly less than the thickness. of the package. This permits the package to be. readily inserted between the rollers but, at the same time permitsthe pressure roller, under the action of spring, to apply yielding pressure or force against. the pac kage'.

Inside the tubular shaft 38 I providev an electric. heating element 49 which is connected by leads 50 to;a control unit 51, which, in turn, is connected by leads. 52 to. .a suitable source of electric power. Thecontrol unit :51 may be of an desired adjustable, type and is adjusted so as to maintain the temperature of the pressure I roller at between approximatelyl and to the boiling point of water.

As in the case of the fluid applying roller,,the design and form of the pressure roller is preferably varied with the type of packaging being processed. Thus, in connection with a relatively thin, flat package such as a package of sliced bacon, a relatively longtransversely concave roller is employed, as shown at 53 in Figs. 1, 2, 5 and 7. The roller 53 is mounted on a tubular sleeve which fits snugly over the shaft 38. The roller may be made of a suitable metal such as aluminum and prefer ably has a fabric tape tightly wound around thesurfaee thereof. In connection with a relativelythicker, flat package, a cylindrical roller, such as shown at .54 in Figs. 3, 4 and 6, is preferably employed. The roller 54 is likewise-made of a suitable metal such as .al I g and the surface of the roller may beknurled, ifidesl d As previously stated, my apparatus maybeemployed for applying labels to a package andfor heat-sealing; package and this is frequently true when my machineis assent used with a relatively thicker package, such as a package of luncheon meat. For this purpose, I mount on the arms 41 a pair of uprights 55 which serve to support a roll 56 of labels 57 made of paper or other suitable sheet material. The bracket assembly for supporting the roll of labels also includes the depending arms 58 and 59 for the guide rods 60 and 61 under which the ribbon of labels is fed. From the rod 61 the labels are thence fed over the top of the heated pressure roller 54. A ring roller 62 carried by the ends of the pivoted arms 63 rests under the force of gravity against the upper surface of the pressure roller and the labels are fed between the ring roller and the pressure roller. In this connection the roll of labels, the supporting brackets and ring roller occupy no more than one half the width of the pressure roller and are so arranged and assembled with the machine as shown in Figs. 4 and 6 to cooperate with one end of the pressure roller.

The labels have a thermoplastic adhesive applied to one surface thereof, said surface facing inwardly towards the center of the roll, as shown in the drawings. Thus, when the labels are fed over the heated pressure roller 54, the adhesive surface faces upwandly away from the pressure roller. The contact area between the ring roller and the pressure roller is relatively small. The heat from the pressure roller serves to pre-heat the thermoplastic adhesive so that it has suflicient surface tackiness to adhere to the package when applied thereto.

The label supporting and feeding assembly can be applied to the arms 41 when it is desired to alfix a label or seal to the packages and may be removed when no label is to be applied.

As shown most clearly in Figs. 1 and 2, an adjustable platform 64 may be provided at the leading end of the apparatus for supported packages before they are fed between the rollers. The adjustable platform takes the form of a fiat platen having depending end flanges with arcuate slots 65 formed therein. The arcuate slots are engaged by the wing nut assemblies 66 carried by standards 67. By loosening the wing nuts 66 the relative angle of the platform may be adjusted. Where my apparatus is used for processing relatively thin, flat packages, the platform 64 serves very satisfactorily. Where my apparatus is used with a relatively thicker, flat package, not only for shrinking the wrapping material but also for applying a label or seal thereto, then I prefer to apply the supplemental platform 68 to the platform 64.

As shown in Fig. 9, supplemental platform 68 is formed in stepped relationship with a relatively higher platen 69 and relatively lower platen 70 both mounted on a base 71 which, in turn, is secured to the platform 64 by screws 72 passing through slots formed in the base. The supplemental platform 68 is so arranged that the higher platen 69 is in the same horizontal plane as the upper surface of pressure roller 54 and it is arranged in alignment with the ring roller 62. The lower platen 70 is in alignment with the covered portion 36 of liquid applying roller 34.

At the discharge end of the apparatus I provide a roller type conveyor 73 consisting of angularly disposed arms 74 supporting the rollers 75.

In using my apparatus for processing a relatively thin, flat type of package, I first assemble the machine as shown in Figs. 1, 2, 5 and 7, by placing the fluid applying roller 31 over the cylinder 28 and the concave pressure applying roller 53 over the tubular shaft 38. The adjusting screw 44 is adjusted so that pressure roller 53 is spaced a slight distance above the fluid applying roller less than the thickness of the package. Tank 16 is filled with water to the proper level and the heating mechanism is turned on so as to cause the water and the pressure roller to assume a temperature of approximately 190 to the boiling point of water.

A package 76, of the general type that may be used, is shown in Fig. 12. The package is arranged in fiat,

thin form and a sheet of heat-shrinkable wrapping mate rial has been wrapped over the display face and the sides of the package and then is overlapped at the rear or base of the package. The longitudinal seam 77 may be heat-sealed across the base of the package before the side edges 78 are folded over. The package 76 is placed upon the platform 64 before the side edges 78 are folded inwardly. The drive mechanism is set into operation and the side edges 78 are folded inwardly while the package is fed between the rollers 31 and 53 with the display face of the package in contact with the fluid applying roller 31 and the base of the package having the folded material disposed thereon in engagement with the dry heated pressure roller 53. The heated water, picked up by the roller 31, is applied to the wrapping material over the entire display surface thereof with the result that the wrapping material is uniformly shrunk. Simultaneously, the heated pressure roller applies dry heat to the base of the package, sealing the folded over edges 78 and preserving the folded material at the base of the package in dry condition. The pressure exerted by the pressure roller not only causes the water in the fluid applying roller to be expelled from the absorbent surface thereof but also under yielding pressure, forces all or most of the air from inside the package out through the seams before final sealing thereof. The completed pack age is discharged from between the roller onto the discharge conveyor 73.

When my apparatus is used for processing a relatively thicker package and for applying a label. or heat seal thereto, I then assemble the fluid applying roller 34 with the cylinder 28 and the pressure roller 54 with the shaft 38. In addition, the label supply roller 56 and the associated mechanism is applied to the arms 41 and the labels are fed beneath the guides 60 and 61 and thence between ring roller 62 and pressure roller 54. As in the first form of my invention, water to the desired level is placed in tank 16 and the heating mechanism is set into operation so as to cause the water and the roller to assume a temperature of approximately 190 to the boiling point of water.

A package of the general type shown at 80 in Fig. 13 may then be processed by my apparatus. This package is flat but relatively thicker than the package shown in Fig. 12. The heat-shrinking wrapping material is wrapped over the display face and side surfaces of the package and thence folded over the base and lightly heat-sealed in place as shown at 81 and 82. The packages are placed upon platen 70 of. the supplementary platform and the drive mechanism for the rollers is set into operation. A preheated label 57 is torn from the supply of labels coming between pressure roller 54 and ring roller 62 and the tacky side of the label is then placed against the base of the package with the printed material facing outwardly. The package with the label thus lightly held in place is then fed between the surface 36 of the roller 34 and pressure roller 54. The pressure roller applies dry heat to the label and base of the package with the result that the label is firmly sealed in place and the base of the package is maintained in dry condition. Simultaneously the squeezing action of the pressure roller causes the coated surface 36 to discharge the heated water over the display face and over the side surfaces of the package. In this connection, the leading and trailing faces of the package likewise receive hot water as the package is fed into and out of the roller. The application of the hot water over the display face and side surfaces of the package causes uniform shrinking of the material with the result that it presents a smooth, unwrinkled appearance.

As the package is fed between the rollers 34 and 54, roller 54 will be caused to rotatea sufiicient amount to feed another pre-heated label into position on the platen '7 fromyiuside thc' relatiitelyithickenpackage, duetoithefact that ,.the wrapping material was only lightlysealeiover the bases ,of .s-th e. package. before, passing. through the machine, so .that .the air is :free. to escape through the folded. layers .of material.

'ItlWlll thus be. .seen that I have provided improved apparatusgfor heattshrinking wrapping material around a package by the application of aaheated :fluid, particularly hot=water,..to controlled areas .of the package without submerging theipackagein thefiuid. 1 thereby accomplish uniform shrinking .of.the wrapping material over the display} surface ,wi't-houtinterferring. with the sealing of the packageordamaging the. contents thereof. My apparatus also effectively seals t-he package and may be used for applying labels thereto, In addition, all or substantiallyall of the'ai ris removed-from the package by the yielding pressure exerted by the rollers. Modifica- -tionsmay be-m ade intheillustrated embodiments of my invention without departing from the invention as set forth-in the accompanying claims.

:lelaimz Apparatus for heat-shrinking wrapping material around a'p ackage comprising: a container for holding a liquid; means for heating aliquid in said container; 21 rollerjrotatably mounted adjacent said container, said container and roller being arranged so that heated liquid fromthe container is applied to the roller; a pressure member mounted in parallel operative relationship with the roller; means for heating said pressure member; and means for urging said pressure member and roller towards each other'under yielding-force whereby a package fed therebetween has yielding pressure applied to the opposite sides-thereof with dry heat applied to one surface and heated liquid applied to another surface.

2. Apparatus for heat-shrinking Wrapping material around a package as set forth in claim 1 in which the liquid applying roller has a yielding liquid absorbing surface.

3..Apparatus for heat-shrinking Wrapping material around a package as set forth in claim 1 in which the liquid applying roller has a yielding liquid absorbing surface extending around at least a portion thereof and also has a pair of spaced radial flanges with yielding liquid absorbingsurfaces.

8 4- ..A aata as t qr, thaae hxinkins Mannin .imterial arounda r-pasls .et a e; 'i l m havin f t uppo in sa supp yf-Q he ssali ab lsa d nt i means, are-P heate Pgfisfifl! .s Q .si icl ns... d, labe s o e the embe u t tztherqwi br ink n Mappin m t ria aroundapa kag ja set or hin cl im 1 hav ng pons an leyetiiquid supply ng dev ce onthe con ain r. in h form of acompletely; enclosed supply tank with a nozzle depend ng .downwardly {into th q ntaineriosga.pre-deterw mined level.

6. Apparatus .for =heat-shrinking wrapping material around apackagev comprising: .a c0ntainer.;for holdinga liquid; .meansfor maintainingthe liquid in the container atia substantially constant level; meanstfonheatingwthe liquid in .the .container; .a shaft rotatably .mounted time mediately adjacent. the container; a. liquid applying roller having a yielding liquid absorbing-surface "removably mounted onrsaid shaftso. as. to .bepartially. immersed; in a liquid. in saidcontainer; a second. shaft rotatablymounted in spaced parallelrelationship with respectto the first shaft; a pressure..roller..removably. mounted on said second shaft; tmean seforheating. saidpressure roller; and yielding. means for urging. said. shafts andv rollers. toward each other .whereby .a. package fed between. therollers has yielding pressure,applied toopposite sides thereof with dry-.lieat applied to.cinesurfaceandheated liquid. applied to anotherasurface.

RefetencesCited in theme. of, this patent UNITED STATES PATENTS 1,476,419 .Robbins... Dec. .4, 1923 1,851,709 :Laucks -.M-ar. 29,1932 2,037,631 Hultin Apr. 14,1936 2,097,427 Bergstein Nov. 2, 1937 2,168,551 McCoy. Aug..8, 1939 2,274,495 -.Muen'cl -i. Feb. 24, 1942 2,420,763 vVVellS May. 20, ;l947 2,538,025 Moore. Ian. 16, 1951 2,586,580 Truscott Feb. 19, 1952 FOREIGN PATENTS 669,775 Great Britain Apr. 9, 1952

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