US2882662A - Heat sealing packaging machine - Google Patents

Description

April 21, 1959 5. J. CAMPBELL HEAT SEALING PACKAGING MACHINE 5 Sheets-Sheet 1 Filed Nov. 12, 1954 A I7zm52722 Samue/ J (0 /77 066// AM i M fix I .I i lliu ialivlivfliil li i .J XESEW April 21, 1959 5. J. CAMPBELL 2,882,662

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HEAT SEALING PACKAGING MACHINE I Filed Nov. 12, 1954 5 Sheets-Sheet 5 HEAT SEALING PACKAGING MACHINE Samuel J. Campbell, Green Bay, Wis., assignor to Food Machinery and Chemical Corporation, San Jose, Calif., a corporation of Delaware Application November 12, 1954, Serial No. 468,285 6 Claims. (Cl. 53-182) This invention relates to a heat sealing packaging machine and method. The machine invention represents an improvement on the device of my prior Patent No. 2,682,331.

The machine is of the type in which a continuously moving web of wrapping material is channeled downwardly about a procession of moving objects and closed beneath the objects to entube them, the resulting tube of wrapping material being subsequently severed intermediate the entubed objects.

According to the present invention, the wrapping web, after being formed about the work, has its marginal portions flanged downwardly and there sealed to each other in face to face abutment while the wrapping web and the entubed work are still within the former. Thereafter, still within the former, a multi-ply flange resulting from the sealing operation is folded over on to the under surface of the wrapping tube. The seal thus made is subsequently perfect hermetically, being considerably superior to a heat seal made by simply lapping the margins of the wrapper horizontally. Thus, when the Wrapping tube is severed intermediate successive work pieces and, desirably, heat sealed transversely at both sides of the line of severance, a substantially completely sealed package results. The invention has been used commercially in wrapping stacks of super-imposed slices of meat products in wax paper.

A further feature of the invention consists in the heating of the entire former to an accurately controlled temperature such as to facilitate the movement through the former of coated paper without substantial deposits of the coating on the metal of the former.

In the drawings:

Fig. 1 is a diagrammatic view in side elevation of a portion of a machine embodying the invention.

Fig. 2 is a plan view on a materially enlarged scale of the portion of the said machine which includes the former for entubing the work pieces in the wrapping web.

Fig. 3 is a fragmentary view in side elevation of a portion of the machine.

Fig. 4 is an enlarged detail view of the former as it appears in side elevation, other portions of the machine being omitted.

Fig. 5 is a view in cross section taken in section on an enlarged scale on the line 55 of Fig. 3.

Fig. 6 is a fragmentary detail view in perspective of the delivery end of the former.

Fig. 7 is a fragmentary detail view taken in section on an enlarged scale from the line 7-7 of Fig. 3.

Fig. 8 is a diagrammatic view in perspective fragmentarily illustrating successive steps in the progress of the Web through the former.

Fig. 9 is a view in perspective of the inverted package produced by the machine.

The objects 10 to be wrapped are fed into the machine on the infeed conveyor or conveyors, three of which are used in the instant design as best shown at 11, 12 and 13 in Fig. 2. For many purposes, a single infeed conveyor wide enough to carry the work may be used. In the instant design, the conveyor 12 is somewhat longer than conveyors 11 and 13 to provide added propulsion for the work pieces as they enter the former 15.

The wrapping web 16 is drawn from a parent roll 17 and passes over appropriate tensioning rolls to the guide roll 18, from which the web 16 passes into the former in the general manner shown in Fig. 5 of my Patent 2,682,331.

The former 15 comprises a box-shaped chamber desirably provided adjacent its receiving end with a pair of flaring wings at 19 which project laterally from its downwardly inclined margins and assist in guiding the web 16. The web being considerably wider than the former and being initially channeled upwardly. As indicated in Fig. 1, the margins are progressively turned downwardly and forced beneath the work pieces 10 until the work pieces are partially entubed.

In the device of the patent aforesaid, the forming box had bottom wall portions which extended across each other in mutually lapping relationship to force the side margins of the wrapping web into correspondingly lapped positions. In the present device, the former 15 is provided, as best shown in Figs. 4, 5 and 8, with bottom wall portions at 20 and 21 which, instead of lapping, are flanged downwardly at 22 and 23, respectively, to provide a downwardly opening slot at 24 into which the side margins 25 and 26 of the wrapping web project into substantial face contact. The flanges 22 and 23 of the forming chamber bottom are not continuous but may be relatively short as indicated in Figs. 3 and 4. They have downwardly inclined lower margins as shown at 27 in Fig. 4 and then, desirably, they terminate abruptly in the vertical margins 28, to leave the side marginal portions 25 and 26 of the web exposed during" the continued advance of the web and the entubed work pieces.

As the web advances beyond the spaced parallel flanges 22 and 23, its depending marginal portions 25 and 26 encounter heat sealing rolls 30 and 31 which are best illustrated in Fig. 8. The forming chamber in which the web 16 is still held is cut away in Fig. 8 at this point in order to expose the entubed web and heat sealing roll. The actual mounting and driving connections for the rolls are best shown in Fig. 2 and Fig. 3, the latter illustrating one of the heating elements 32. The rolls are desirably, although not necessarily, peripherally ribbed or toothed at 33 to crimp the heat sealed marginal portions 25 and 26 of the wrapper as such portions are laminated together by the heat and pressure of such rolls. A substantially hermetically tight seal is provided between the marginal portions of the wrapper thus heat sealed together in face contact.

During the continued movement of the wrapper through the forming box or chamber 15, the laminated margins of the wrapper, now identified by reference character35, are engaged by a flange 36 projecting laterally from the bottom portion 20 of the forming chamber and lapping beneath the bottom portion 21 of such chamber as best shown in Figs. 6 and 8. Elongated inclination of the margin 37 of the downwardly offset lapping flange 36 gradually turns the laminated wrapper margins 35 to the position shown in Fig. 8 and Fig. 9.

Thereafter the continuously moving tubular web and the entubed work pieces therein pass beneath the trans verse crimping and severing rolls 38, 39 which are of the general type best disclosed in Figs. 2, 3 and 4 of my Patent 2,546,721. These rolls are so timed as to operate upon the tubular wrapper intermediate the entubed work pieces to crimp and heat seal portions of the wrapper Patented Apr. 21, 1959 3 which are transverse at 40 and 41 (Fig. 9) and to sever the wrapper through the areas thus sealed to produce hermetically sealed packages as shown in Fig. 9. Fig. 9 shows the package inverted to illustrate the laminated margins 35 of the wrapper as they appear when folded over on the bottom surface of the work pieces.

Particularly where the wrapper comprises a coated paper such as wax paper, it is desirable to heat the interior of the former, at least throughout the length of that portion of the former about which the paper is drawn and channeled during the entubing operation. As shown in Figs. 2 to 5,1 provide heating elements 42, 43 supplied with current at 44, 45, respectively, and disposed in the upper part of the former above the floating pressure plate 4 6 which rests on the wrapper tube and the entubed work pieces. A thermostat shown diagrammatically at 48 projects into the former from a point near the discharge end of its heated section. It is connected by the wires 49 in controlling relation with the conductors 44 and 45 leading to the heating element. A suitable control is provided at 50 for thermostat adjustment. The heating elements within the former keep the metal surfaces traversed by the coated web at a temperature just sulficiently high so that the coatings on the web become somewhat softened and, in effect, lubricates the metal surfaces to promote free --web movement. Paraflin and other coatings do not stick to or gum up metal surfaces which are appreciably warmer than the coating.

It will be observed that the forming operation is really conducted in two steps, the heat sealing rolls acting to laminate together the parallel marginal portions of the web after the web has been drawn about the work pieces and before any marginal portion thereof is forced into lapping position beneath the botom of the tube. By performing the heat sealing operation while the flanges are projecting parallel to each other and in the same downward direction, it is not only possible to draw the web very snugly about the work pieces, but. it is also possible to seal the web much more tightly than through the use of previously known procedures or apparatus. Particularly when the work pieces are relatively soft, no great amount of sealing pressure can be exerted on upwardly lapping and oppositely directed margins of the web because such pressure would necessarily be communicated to the work pieces. As compared with the very slight pressure possible under such circumstances, I am able to use pressure limited only by the strength of the web itself. In the instant device, the requisite pressure is developed by mounting the heat sealing roll 36: on .a slidable bearing block 52 subject to the adjustable bias of compression springs 53.

Entubed work pieces may be moved from the former in any desired manner. In the device illustrated, I use the lateral belts 55 and 56 as described in my Patent 2,546,721. The driving connections for the various parts are illustrated but, so far as the present invention is concerned, they may be operated in any desired manner. They are more fully described in my two prior patents herein identified.

The device and method herein disclosed may be used to wrap a wide variety of work pieces. They were developed particularly for the wrapping of stacks of sliced meat products under circumstances such that a very tight seal was desired. Accomplishment of such a seal is an easy matter with the apparatus and method disclosed.

While the method has been described incidentally in the course of the foregoing description of the device, it may be summarized as follows:

The wrapping web is pulled through a forming box which first channels the web by turning its margins progressively downwardly about a succession of mutually spaced work pieces fed into the box beneath the web. As the forming operation continues during the progressive advance of the'web and the workpieces, the web is folded beneath the work pieces with its free margins turned downwardly at a point centrally beneath the advancing work pieces.

Thereupon the free margins of the web are exposed, being substantially in face contact and both projecting in the same downward direction. During the continued ad- Vance of the web and the partially wrapped work pieces, the margins are sealed to each other, desirably by laminating heat and pressure, although, in the generic aspects of the method, any other sealing or connecting means may be employed at this point.

Thereafter, during continued movement of the web and the now enclosed work pieces, and desirably while the web is still tightly encased in the forming chamber, the connected 0r laminated margins are folded over upon the lower face of the resulting tube to complete the entubing of the work pieces, after which the tube is severed intermediate successive work pieces and is transversely heat sealed along the margin of severance to provide a wrapper in which each work piece is substantially hermetically sealed.

I claim:

1. A former for a wrapping machine, comprising two substantially horizontal wall portions adapted to support work pieces during wrapping thereof, said wall portions being laterally spaced one from the other to provide a longitudinally extending slot therebetween, said slot being adapted to receive side marginal portions of a web of wrapping material, a pair of parallel longitudinally extending spaced apart flanges projecting downwardly from the side edges of said slot respectively, a pair of heat sealing members located at opposite sides of said slot respectively and aligned with said pair of downwardly projecting flanges, and pressure means laterally urging at least one of said heat sealing members toward the other of said members.

2. A former for a wrapping machine, comprising two substantially horizontal wall portions adapted to support work pieces during wrapping thereof, said wall portions being laterally spaced one from the other to provide a longitudinally extending slot therebetween, said slot being adapted to receive side marginal portions of a web of wrapping material, a pair of parallel longitudinally extending spaced apart flanges projecting downwardly from the side edges of said slot respectively, a pair of heat sealing members located at opposite sides of said slot respectively and aligned with said pair of downwardly projecting flanges, at least one of said members being movable with respect to the other member, and pressure means laterally urging said movable member toward said other member.

3. A former for a wrapping machine, comprising two substantially horizontal wall portions adapted to support work pieces during wrapping thereof, said wall portions being laterally spaced one from the other to provide a longitudinally extending slot therebetween, said slot being adapted to receive side marginal portions of a web of wrapping material, a pair of parallel longitudinally extending spaced apart flanges projecting downwardly from the side edges of said slot respectively, a pair of heat sealing rollers located at opposite sides of said slot respectively and aligned with said pair of downwardly projecting flanges, at least one of said rollers being mounted for movement with respect to the other roller, and spring means laterally pressing said movable roller toward said other roller.

4. A former for a wrapping machine, comprising two substantially horizontal wall portions adapted to support Work pieces during wrapping thereof, said wall portions being laterally spaced one from the other to provide a longitudinally extending slot therebetween, said slot being adapted to receive side marginal portions of a web of wrapping material, a pair of parallel longitudinally extending spaced apart flanges projecting downwardly from the side edges of said slot respectively, a pair of heat sealing rollers located at opposite sides of said slot respectively and adjacent said pair of downwardly projecting flanges, a bearing block for one of said rollers, said bearing block being movable toward the other said roller, and spring means biasing said bearing block toward said other roller, whereby said one roller is urged toward the other said roller under positive lateral pressure.

5. A former for a Wrapping machine, comprising two substantially horizontal wall portions adapted to support work pieces during wrapping thereof, said wall portions being laterally spaced one from the other to provide a longitudinally extending slot therebetween, said slot being adapted to receive side marginal portions of a web of wrapping material, a pair of parallel longitudinally extending spaced apart flanges projecting downwardly from the side edges of said slot respectively, a pair of heat sealing members located at opposite sides of said slot respectively and aligned with said pair of downwardly projecting flanges, and a folding flange adjacent said heat sealing members on the side thereof opposite said downwardly projecting flanges, said folding flange merging at one side with one of said Wall portions, and being downwardly ofiset and extending beneath the other of said wall portions.

6. Apparatus for wrapping articles, comprising conveyor means for continuously advancing an article to be Wrapped, means for continuously advancing a Web of wrapping material toward said article, a former adapted to shape the Web of wrapping material progressively about the top, sides and bottom of the article, said former being provided with means for turning downwardly beneath the article the opposed marginal side portions of the web of wrapping material, means for sealing together the downwardly turned web side portions, and means for folding the sealed web side portions upwardly toward the undersurface of the wrapped article.

References Cited in the file of this patent UNITED STATES PATENTS 2,018,806 Richard Oct. 29, 1935 2,142,505 Gammeter Jan. 3, 1939 2,218,585 Merkle Oct. 22, 1940 2,331,927 Palmer Oct. 19, 1943 2,422,188 Epstein June 17, 1947 2,555,758 Noble et al June 5, 1951 2,602,276 Campbell July 8, 1952 2,762,178 Campbell Sept. 11, 1956 Disclaimer 2,882,662.-Samuel J. Campbell, Green Bay, WVis. HEAT SEALING PACK- AGING MACHINE. Patent dated Apr. 21, 1959. Disclaimer filed July 28, 1967, by the assignee, FMU Corpomtz'on. Hereby enters this disclaimer to claim 6 of said patent.

[Oficz'al Gazette October 3, 1967.]

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