US3094905A - Process for making bags - Google Patents

Description

June 25, 1963 A. B. HASLACHER 3,094,905

PROCESS FOR MAKING BAGS Filed July 8, 1960 2 Sheets-Sheet 1 BY M "Y A 7mm/16 June 25, 1963 A. B. HAsLAcl-IER 3,094,905

PROCESS FOR MAKING BAGS Filed July 8, 19,60 2 Sheets-Sheet 2 61 o @t 65A Il F65 il," 6l 5 1 I 54- 53 l 54 35 af 27 v 29 (31 f I j 27 9 32 z? E [Il z5 .I E' 3l 36 I 6 2e d 32' ,@IV 3a l 27 Z9 Z235 m37 IN V EN TOR.'

A TTRNKS United States Patent Office Patented June 25, 1963 3,094,905 PROCESS FOR MAKING BAGS Alfred B. Haslacher, deceased, late of San Francisco, Calif., by Robert L. Haslacher, administrator, 817 Greenwich Place, Palo Alto, Calif.

Filed July 8, 1960, Ser. No. 41,701 1 Claim. (Cl. 93--35) This invention relates generally to improvements in the art of producing bags -of the gusseted type with certain modifications and refinements. The invention is directed more particularly to the continuous production of completely formed, folded and properly sealed bags from a continuous source of sheet material normally supplied in roll configuration.

A primary object of this invention is to provide means for commercially producing an improved, superior gusseted bag utilizing an eicient method of inexpensively forming a rectangular or squared bottom in conjunction with the sealing of the transverse or 'bottom terminal ap.

It is well known in the packaging industry to fabricate bags of the type commonly called automatic or squarebottomed in which the bag-opening motion will result i-n the bottom -portion assuming a transverse position so the bag will stand in an upright position to Afacilitate lling. However, this type of bag has previously been expensive to manufacture because of the various slitting, trimming and pasting operations which must be performed on the bottom.

The ordinary type of side gusseted bag is cheaper to produce but is considered less acceptable for commercial use since it is more difficult to open and does not provide other desirable handling advantages of the above-mentioned automatic bags. In addition, this type of bag normally is not properly sealed against seepage therethrough of liquids or fine-grained materials.

The chief aim of the present invention is to enable the economical manufacture of large quantities of bags incorporating the best features of both -t-he automatic and gusseted type bags with special apparatus providing for the forming of a rectangular bottom substantially with the bag bottom or terminal flap sealing operation.

More particularly, it is the primary object of this invention to facilitate the manufacture of reliable bags by utilizing a mechanism including a reciprocating expansible ram during the manufacturing process to transform the ordinary gusseted bag into one having the generally dcsirable handling characteristics and features of that type known in the art as an automatic bag.

It is a further object of the present invention to enable the expeditious production of goperly sealed bags by the addition of extra adhesive material in a particular manner to completely fill the voids at the terminal ap occasioned by the material folding and over-lapping process. This procedure obviates the possibility of leakage at the flap upon completion of the forming and sealing operation, and also precludes the necessity for utilizing the usual staggered die-cutting and special folding and handling of the bottom portion.

Other objects and advantages of the invention will become apparent from the following detailed description of the attached drawing wherein:

FIG. l is a diagrammatic view illustrating generally the sequence of operations utilized -to produce a bag;

IFIG. 2 is a side view of the bag ap sealing mechanism with the bottom shaping ram shown in the inoperative position;

FIG. 3 is similar to FIG. 2 but with the apparatus in the operative or extended position;

FIG. 4 is a top view of the expansible ram in closed position;

FIG. 5 is an end view of the ram in open or bottom forming position;

IFIG. 6 is a side view of a partially folded bag;

FIGS. 7, 8 and 9 are sequential views of a bag yduring various stages of the bottom for-ming operation;

FIG. 10 is an exaggerated cross-section of a sealed terminal flap;

IFIG. 11 is a view of the adhesive applying bar;

FIG. 12 is a partial view of the sheet material showing the placement of adhesive thereon.

Referring now to the drawings, the major parts and mechanisms required to complete the forming, shaping and sealing operations are shown diagrammatically in FIG. 1 to illustrate the sequence of the manufacturing operation. A web of flat sheet material 10 -is supplied from a rotatably supported roll 11, is guided around a tension control mechanism 12 and roller supports 13 to receive a continuous stripe of adhesive along one margin from applicator 14 to provide for the longitudinal seam -to be completed later. A second applicator device 15 provides a special transverse band of adhesive at the proper predetermined longitudinal intervals for the subsequent terminal flap sealing operation. Scoring of the sheet for later folding may also be accomplished at this point utilizing the usual methods.

The sheet material is next formed into a generally open tubular configuration with reentrant flaps folded inwardly by a tube forming unit 16, passing around the support- -ing leg of the reciprocating ram framework 17 to the longitudinal seaming unit 18. The completed tube then moves over the expansible forming mechanism 19 at the extremity of ram framework 17 to the transverse or terminal flap sealing unit 21-where the bottom is shaped to the desired rectangular or squared conformation while the terminal flap is being sealed.

The functions of the reciprocating drive mechanism and the expansible ram for shaping the bag bottom against the transverse sealing xture are best shown in FIGS. 2 and 3. As previously stated, the web of sheet material 10 is fed around the upright supporting leg 22 of the reciprocating ram framework 17 in the form of an uncompleted tube open at its top. A fluid operated cylinder 23 is mounted on leg 22 and functions through bell crank lever 24 against the pull of spring 25 to move the sliding ram element 26 horizontally in the grooved guide members 27 of the ram framework 17. Spring 25 may be omitted if the drive cylinder 23 is of the double-acting type or positively driven in both directions.

Pivotally connected to the projecting end 28 of reciproeating element 26 are two sets of connecting lever arms 29 and 31. (Also see FIGS. 4 and 5.) The opposite ends of levers 29 and 31 are hingedly pinned by means of integral upstanding lugs 32 to bottom shaping plates 33 and 34. 'I'hese plates are also pivotally supported at their inner ends on extensions 35 of grooved guide members 27 by means of shaft 36. Thus, longitudinal movement of slider element 26 with reference to guide members 27 will cause plates 33 and 34 to rotate outwardly about the shaft 36 until mating edges 37 engage each other so that the plates form a continuous unbroken at surface. Opposite edges 38 of plates 33 and 34 are preferably slightly bent radially to prevent tearing of the material during the bottom shaping operation.

The transverse terminal flap sealing unit 21 comprises a pair of spaced, cooperating rotatable elements 41 and 42 each of which 4is made up of supporting arms 43 pivotally mounted as at 44. Generally ilat plates 4S are attached to the forward ends of arms 43 to which are also attached the transverse sealing bars 46. Plates 45 and sealing bars 46 serve together to form a smooth surface against which the bag material is pressed during the shaping procedure. Sealing bars 46 may be of the electrically heated type if desired for the simultaneous application of heat and pressure for the sealing of thermoplastic sheet material or the like. Either one or both of the sealing bars 46 may be provided with relieved portions 1n the working face to accommodate the increased thickness of the material lat the seam and gussets, A cutoi knife 47 and cooperating shearing jaw 48 may be attached to elements 41 and 42 to provide for severing the continuous tube simultaneously with the sealing operation.

A generally claw-shaped assembly 51, comprising an arcuate plate 52 and supporting arms 53 is pivotally supported at fulcrum points 54 and is adapted to be rotatably operated (by means not shown) in a counterclockwise direction immediately after retraction of the bottom shaping plates to their closed position. Edge 55 of plate 52 is adapted to contact the top side of the squared bag to induce folding of the material along the previously applied score line 56 so the bag will attain the configuration shown in FIG. 6. The terminal flap may be folded over by any known mechanism and adhesively secured if deemed essential.

If it is found to be necessary for expeditious operations, pivoted tucking fingers 61 may be provided for initiating the infolding of the triangularly shaped portions 62 of the guests during the collapsing or flattening of the squared bag bottom, score lines 63 having previously been applied in the proper location. Fingers 61 are rotatably mounted on rod supports 64 and are operated simultaneously with the actuation of bottom shaping assembly. Springs 65 are provided to bias the ngers against actuating rods 64 but permit the fingers to move out of the way as the bag progresses past the shaping assembly and between the two parts of the terminal ap sealing mechanism to the finished bag stacking trays (not shown).

The sequence of the squared bottom bag shaping and folding operation is best illustrated in FIGS. 7, 8 and 9; wherein FIG. 7 shows the generally tubular end portion 66 as it appears after the transverse bottom sealing operation of terminal ap ,67 has been completed, the longitudinal overlap seal 68 having been previously accomplished by unit 18. Sealing bars are omitted for clarity. FIG. 8 shows the end portion 66 after the squaring operation has been completed by actuation of the reciprocating ram, and consequent pressure of the shaping plates against the iap sealing unit. The folding score line is indicated at 56 and the triangularly shaped infold portion is located at 62 with score lines 63. In FIG. 9 the end has been severed and the resulting bag is illustrated in the completely atened position ready for stacking and packing.

FIG. l is an exaggerted transverse cross section` through the terminal flap 67 at the bottom of a bag which has been sealed in accordance with one embodiment of this invention. At the extremities 71 of the inner folds of the reentrant iiaps 72 and at the inner end 73 of overlap 68 there normally exist areas which are devoid of sealant by virtue of the ifset of the sheet material at these points. In order to satisfactorily fill and seal these voids, adhesive is applied in suiicient volume on speciiic areas of the sheet material prior to the flap sealing in a manner to be explained.

An adhesive applying bar 76, shown in FIG. 1-1, is

.4 a part of the applicator device 15 previously mentioned. Bar 76 is fabricated with the required number of slots or indentations 77 to provide for transfer of additional adhesive at predetermined spots. The slots 77 are appropriately spaced in accordance with the dimensions of the bag being fabricated. It will be readily apparent that by having an increased amount of adhesive applied to the sheet material at speciic areas of the transverse band 78, this surplus can be utilized to advantage to prevent voids from occurring in the completed terminal ap seal. Slot 77a is properly located to take care of the over-lap at 73 While a pair of slots 77b cooperates to supply additional adhesive to accommodate the usual void at the inner end 71 of one re-entrant ilap and similarly pair 77c the opposite ap.

The placement of these heavier quantities of adhesive on the sheet material prior to the folding operation can best be Seen in FIG. l2, wherein the darker shaded areas indicate the surplus applied for obviating the voids which result from the usual manufacture of terminal flap seals. Preferably, the adhesive is of heat sealing nature in order that a siftproof bag be produced.

What I claim is:

'I'he process of producing bags from sheet material comprising:

(a) continuously advancing a continuous web of sheet material;

(b) applying a continuous adhesive stripe to one 1ongituslinal margin of the continuously advancing materi (c) applying transverse bands of adhesive at right angles to said stripe of adhesive material said bands .being applied at predetermined spaced intervals along the length of the material and said band of adhesive being applied in varying amounts across the width of the material with the greatest amount of adhesive being applied at points corresponding to offsets on the finished bags;

(d) thereafter folding the sheet material to form a generally flattened tube having inwardly disposed gussets, the outer edges of the material being overlapped and united along the line of the adhesive stripe;

(e) pressing an end of the generally flattened tube together to form a transverse, face-to-face seal;

(f) expanding the thus sealed end of the bag to form la rectangular bottom by exerting force from inside the -bag against the bottom of the bag;

(g) folding said bottom against |a sidewall of said bag; and

(h) severing the material to form the completed bag detached from the web of material.

References Cited in the file of this patent UNITED STATES PATENTS Appel Aug. 28, 1888 v

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