US3085478A - Apparatus for the production of bags from precut leaves with thermoplastic - Google Patents

Description

April 16, 1963 A, EGLI APPARATUS FOR THE PRODUCTION OF BAGS FROM PRECUT LEAVES WITH THERMO-PLASTIC Filed Aug. 11, 1960 United States Patent O APPARATUS FOR THE PRODUCTIGN OF BAGS FROM PRECUT LEAVES WITH THERMOPLASTIC Alwin Egli, Neuhausen am Rheinfall, Switzerland, assignor to Schweizerische Industrie-Gesellschaft, Neuhausen am Rheinfall, Switzerland Filed Aug. 11, 1960, Ser. No. 48,944 Claims priority, application Switzerland Aug. 19, 1959 1 Claim. (Cl. 931-12) The present invention relates to the production of bags from pre-cut leaves provided with thermoplastic material at least on the margins to be interwelded for the formation of seams, by the formation of a tube or hose of the `said leaf, interwelding of a longitudinal seam thereof and subsequent folding and interwelding of the bottoms of -said bags.

Hitherto all these operations have been carried out on one and the same mandrel, several such mandrels being combined into a mandrel wheel and being turned stepwise from one working position to the subsequent one, each of the said mandrels being provided with folding members and heating jaws for the formation of the tube or hose and of the seams.

It is an object of the present invention to provide a machine for the production of receptacles and bags of the kind referred to which has a high output while dispensing with a plurality of tube or hose forming and seam forming means.

With-these and other objects in view Which will become apparent later from this specification and the accompanying drawing, I provide an apparatus for the production of bags from pre-cut leaves provided with thermoplastic material at least at the margins to be interwelded by a seam, comprising means for folding a Ileaf into a tube or hose and interwelding a longitudinal seam thereof on a single auxiliary mandrel, moving the said auxiliary mandrel axially towards a main mandrel, transferring the said tube or hose axially from said auxiliary mandrel to the said main mandrel, and folding and interwelding the bottom of said tube or hose on the end face of the said main mandrel.

I also provide a device for the production of such bags, comprising in combination: at least two main mandrels stepwise rotatable into various working position for the folding and interwelding of the bottoms of the said bags, and auxiliary mandrel 4ico-operating with the said main mandrels and axially movable towards the main mandrel actually in juxtaposition with it, a folding box for the folding of the said leaves into a tubular member and heatable clampingand welding-jaws for the formation of protruding longitudinal weld seams of the tube or hose co-operating with the said auxiliary mandrel, and feeder rollers engaging the protruding longitudinal seam of the said tube or hose, and transferring the latter from the said auxiliary mandrel to the said actually juxtaposed main mandrel.

These and other features of my said invention will be clearly understood from the following description of a preferred embodiment of my new device given by way of example with reference to the accompanying drawings, in which:

FIG. l illustrates a longitudinal section of the auxiliary mandrel and a main mandrel of a device for the production of bags,

FIG. 2 is a cross section on line II-II of FIG. l of the auxiliary mandrel with the folding box and the heating jaws in the working position in juxtaposition with the folding box,

FIG. 3 is a cross section like FIG. 2 in the Working position during the welding of the longitudinal seam,

FIG. 4 is a diagrammatic illustration of the transfer of j 3,085,473 Patented Apr. 16, 1963 the tube for the bag by pushing it from the auxiliary mandrel on to a main mandrel, and

FIG. 5 is a plan view to FIG. 4, FIGS. 4 and 5 being on a smaller scale than FIGS. l to 3.

In FIG. 1 an auxiliary mandrel is denoted as at 1, which is axially slidably mounted on two bars 5. The bars `Slare fixed to an arm 6, which is xedly connected to the machine frame. The axial shi-fting of the auxiliary mandrel 1 is effected in the working rhythm of the machine by the rocking of a lever 7, which is connected by a connected rod 8 to the auxiliary mandrel 1. On an axle 9, likewise fixed to the machine frame, two rocker levers 10, 11 are pivoted, which at their lower ends carry two heating jaws 12, 13 serving for the welding of the longitudinal seam. The jaws 12, 13 are electrically heated in a well known and accordingly not illustrated in detail.

Below the auxiliary mand-rel 1 a bi-partite folding box 14 is arranged, which is vertically shiftable from the position shown in FIG. 2 in full lines into a position shown in chain-dotted lines. With its upper surface it forms a table 16 with holders 18 serving for taking in a pre-cut leaf 17, from which the bag is made. The folding box encloses a punch 15, likewise vertically shiftable, which cooperates with the underside of the auxiliary mandrel 1 and forces the leaf 17 to be folded against the same. On the axle 9 moreover a conveyer' roller 19 is pivotally mounted. The same co-operates with a similar roller 20 (FIG. 5) and serves for transferring the tube or hose forl the bag f-rom the auxiliary mandrel 1 to the main mandrel 2. The rollers 19, 20 are driven, in a manner not illustrated, from the principal drive of the machine, i.e. preferably continuously.

On a vertical axle 4 there is arranged a mandrel Wheel 3, having for example four main mandrels 2, one of which is illustrated in section. The vertical shaft 4 is rotated in a step by step manner to successively move the main mandrels 2 into and out of the work station by a suitable mechanism 50 such as is shown in United States Patent 1,020,821 to Hesser, issued March 19, 1912. The lowerwall 2l of the main mandrel 2 is pivotally mounted about a horizontal axle 22 capable of being swung inward against the bias of a coiled spring 23, in order to facilitate the pushing over of the tube or hose for the bag. The inward pivoting of the bottom wall 21 takes place automatically, when the main mandrel 2 runs into theworking position illustrated, opposite the auxiliary mandrel 1. In this position a roller 27 arranged on the bottom wall 21 runs up a fixed abutment 28, whereby the bottom Wall 21 is turned inward. Above the upper edge of the main mandrel 2 there is moreover arranged a clamping jaw 24, which is mounted on a rocker arm 25 co-operating with a lever 26 actuated by the .principal machine drive.

The method for producing the bags comprises the following steps:

A pre-cut leaf or blank 17 is supplied to the table 16, lbeing brought into the correct position by the holders 18. Thereafter the folding box 14 with the punchy 15 move upward. The leaf or blank 17 is forced against the bottom of the auxiliary mandrel 1 by the punch 15. The folding box 14 continues to move upward until the table 16 is flush with the upper edges of the auxiliary mandrel 1 (chain-dotted line position in FIG. 2). The leaf or blank 17 is thereby folded about the two side faces and the bottom portion of the auxiliary mandrel 1. By a rocking movement of the rocker lever 10 the side 17 protruding upward from the leaf or blank 17 is folded by the jaw 12 of said lever about the upper face of the auxiliary mandrel 1. At the same time the lever 11 turns into the position shown in FIG. 3. The margins of the leaf 17 protruding upwardly and provided'with a thermoplastic coating are then compressed by the heating jaws I2, 13 and thus interwelded. Thereafter the jaws 12 and 13 release the protruding margin of the leaf 17, which has now been interwelded to form a hose. The lever 7 then shifts the auxiliary mandrel 1 to the right of FIG. 1, until its end face abuts the adjacent end face of the main mandrel 2. Thereby the forward end of the protruding longitudinal seam of the tube or hose gets between the driven rollers 19 and 20, is engaged by the same land the tube or hose is pushed over the main mandrel which had been in a position of readiness. In order to facilitate the pushing over the lower wall 21 of the latter has been slightly turned upward (FIG. V4). With advantage `moreover the main mandrel is made slightly narrower than the auxiliary mandrel, which likewise contributes to the safe transfer from the auxiliary mandrel. Thereafter the lever 26 forces through the rocker arm 25 the clamping jaw 24 against the main mandrel 2, so that the tube or hose is retained there. The auxiliary mandrel 1 runs back again to its basic position, while the main mandrel 2 is turned about the axle 4 into a further working position, where in a manner known in itself the folding and interwelding of the lbottom of the bag is carried out. Previously the roller 19 has been swung out of its working position, in order to afford a free passage to the protruding seam `during the step-movement of the mandrel wheel which is rotated stepwise according to United States Patent 1,020,821 to Hesser, issued March 19, 1912. The roller 19 could natur-ally be arranged axially adjustably instead of pivotally, for the purpose of releasing at any time the longitudinal seam.

The use of an auxiliary mandrel 1 for the formation of the tube or hose facilitates the formation of a seam, which is faultless over its full length. For this purpose the auxiliary mandrel is made longer than the tube or hose to be produced, while the mainy mandrel 2 -rnust be made shorter than the latter, since one end of the tube or hose must projectbeyond the main mandrel in order that it can be folded for the formation of the bottom of the tube or hose to `form a bag.

While I have herein described and illustrated in the accompanying drawing what may be considered a typical and particularly useful embodiment of my said invention, I wish it to be understood, that I ido not limit myself to the particular details and dimensions described or illus- 4 trated; for obvious modifications will occur to a person skilled in the art.

What I claim as my invention and desire to secure by Letters Patent, is:

In an apparatus for forming bags Ifrom precut blank sheets provided at least Ialong the marginal edges with a thermoplastic material to be interwelded and form a seam along one side of said bag, comprising step by step support means, a work `station spaced from said support means, a rotatable carrier on said support means, a plurality of radially extending main mandrel sections on said carrier movable stepwise into and out of registry with said work station, expansible and retractable sections for each of said radial sections, slide guide means mounted at said work station extending in the same plane as said radially extending main mandrel section on said carrier, an auxiliary mandrel slidably mounted on said slide guide means adapted to be moved toward and away `from the end of each lmain mandrel section while said sections are in their work `station position, means for moving said mandrel toward and away from `said main mandrel sections as they are successively moved to their work station position, a 4forming box beneath said auxiliary mandrel having a forming chamber over which one of said sheets is adapted to be placed and moved upwardly around said auxiliary mandrel, a pair of jaw members mounted above said auxiliary mandrel to engage the free ends of said sheet and move the same into sealing engagement to form a longitudinal upstanding seam, roller means located at said work station to frictionally engage said seam when the auxiliary mandrel s moved to a position adjacent the end of one of said main mandrels, and means for retracting the expansible sections of said main mandrels when the same approach saidwork station to permit said roller means to feed the formed blank'endwise over said main mandrel section.

References Cited in the lile of this patent UNITED STATES PATENTS 2,671,383 Jungmayr Mar. 9, 1954 2,821,121 Vergobbi Jan. 28, 1958 2,854,899 Bauder et al. Oct. 7, 1958 2,966,832 Vergobbi Jan. 3, 1961

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