US1963571A - Method and apparatus for making paper bags - Google Patents

Description

June 19, 1934.

H. s. WEBBER METHOD AND APPARATUS FOR MAKING PAPER BAGS Filed July 21, 19.53 2 sheds-sheet 1- BY r I I jar/V ATTORNEYS.

June 19, 1934. H 5 WEBBER 1,963,571

'METHOD AND APPARATUS FOR MAKING PAPER BAGS Filed July2l, 1953 2 Sheets-Sheet 2 g a IN VEN TOR.

ATTORNEYS.

Patented June 19, 1934 METHOD AND APPARATUS FOR MAKING PAPER BAGS Harold S. Webber, New York, N. Y., assignor to Schorsch & Co. Inc., New York, N.

poration of New York Y., a cor- Application July 21, 1933, Serial No. 681,402

11 Claims.

This invention relates to the manufacture of paper bags and more particularly to a method and apparatus for making a paper bag of the so-called envelope type having an elongated clos- An object of this invention is to provide a method and apparatus for making such a bag expeditiously and without waste of material. This and other objects, which will be apparent to those skilled in this particular art, are accomplished by the invention hereinafter described and diagrammatically illustrated in the accompanying drawings wherein,

Fig. 1 is a diagrammatic sectional view of a bag forming machine constructed in accordance with one embodiment of this invention.

Fig. 2 is a top plan view of the machine shown in Fig. 1. v

- Fig. 3 is a view illustrating progressive steps of the present method of forming bags from the original web material.

Fig. 4 is a view of a finished bag after the adjacent the former so as to extend transversely to the line of travel of the bag tube and somewhat in back of the cutting edge of the former, so that the striker bar, which intermittently strikes through the paper web adjacent the cutters, chops 01f the end of the-web along the lines of such cutting edges to form .bag blanks.-

By having one cutter offset longitudinally of the bag tube relatively to the other, the bag blanks are formed with projecting flaps at each end,

- due to the fact that one side of the web is cut. along the line of the cutting edge of the former,

while the other side of the web is cut along the the latter is ordinarily torn along its side edges The tube is continuously fed along to form the sides of the projecting flaps'and. the length of the tear is equal to the projection of such flaps which in turn is equal to the distance between the cutting edges of the former and the associated cutter. In the usual bag making machines this tearing operation does not always occur along the lines desired and sometimes results in ragged, uneven edges. If the distance is short this uneven or ragged tear is not objectionable but in the case of an elongated flap such tearing results in an unsightly and unsaleable article. By means of the present invention, the uncertainty of this tearing operation is eliminated and the accurate formation of the projecting flaps is assured by weakening the fibers of the bag tube along the side edges .thereof at longitudinally spaced intervals prior to cutting ofi the bag blanks and while the tube moves toward the striker and cutting edges. The construction and arrangement is such, and the timing of the various parts so co-ordinated, that the striker cuts off the bag blanks at the moment when the regions of weakened fiber reach the cutting knives so that the side edges of the tube are readily torn along the lines of weakened fiber to provide smooth-edged, accurately-formed flaps In accordance with the herein described embodiment of the invention, the weakening of the fibers is accomplished by creasing the side edges of the bag tube along the lines to be sub- 35 sequently torn.

The drawings illustrate diagrammatically a machine which is constructed in accordance with one embodiment of this invention. As illustrated, the machine comprises guide rollers 10 over which a web 11 of paper is drawn from a supply roll 12. The web isdirected downwardly under a former 13 of conventional design around .which it is folded to form a fiat bag tube 14 by conventional folding mechanism including the usual rollers. The paste is applied to one edge of the web '11 and the longitudinal seam 16 of the bag tube is pasted together by usual mechanism. An end of the former 13 is provided with a serrated cutting edge 17 and a second cutter 18 is positioned above the former plate and is displaced longitudinally from the end of the platein the usual way but to a much greater degree than has been practicable heretofore. A striker bar 19 is mounted on a rotating striker support 20 mounted on the end of a rotary shaft 21. The bag tube 14 is continuously fed at a relatively high rate of speed by upper and lower pairs of rollers 22 and 23 which engage the surfaces of the bag tube in the usual way. The lower pair of feed rolls are mounted on a driving shaft 24 and the upper pair are driven by suitable gearing from the lower pair.

In accordance with the present invention, the machine is provided with mechanism for weakening the fibers at longitudinally spaced intervals along the side edges of the tube 14.

As illustrated, this mechanism comprises creasing devices formed by a pair of cam rollers 26 mounted on a shaft 27 extending across the machine above the bag tube and supported in vertically adjustable bearings 28. Presser screws 29 are provided for pressing the shaft supporting bearing boxes downwardly to press the cam rollers 26 against the lower cooperating rollers 30. Each cam roller 26 has a circular portion. 31 which constantly engages the periphery of the associated roller 30. Each cam roller has a web creasing cam 32 adjacent the inner face of the circular portion 31 which cooperates with the associated roller 30 at each revolution of the cam roller to crease the edge of the bag tube 14, as indicated in Fig. 5, to weaken the fiber along the lines of subsequent tear when the bag blank is subsequently chopped off from the bag tube. The lower rollers 30 are driven frictionally by the cam rollers 26.

It will be apparent that the mechanism described will provide the opposite edges of the bag tube with spaced lines 33 of weakened fiber due to the creasing operation of the cam rollers. Proper timing of the parts so that the striker bar 19 strikes through the bag tube at the time when the creases 33 extend from the cutting edge 17 to the cutting edge 18 is obtained by mechanism hereinafter described through the medium of which the operation of the striker operating shaft 21 and the cam roll driving shaft 27 are properly co-ordinated. The operation of the striker cuts the lower web of the bag tube along the line of the cutting edge 17 of the former, while the upper web of the bag tube is severed along the line of the cutter 18, the side edges of the tube being torn along the lines of the creases 33. In this way a bag blank is provided having an elongated flap 36 at each end. By weakening the fibers in the manner described the side edges of the fiap are torn along definite lines and the flaps are formed with relatively smooth side edges.

It will be apparent that the creasing operation can be accomplished by means other than the cam rollers 26 as, for example, vertically movable rollers which are periodically moved into and out of creasing engagement with the travelling bag tube.

The bag blanks so formed are then fed by feed rollers 38 to conventional bottom-folding and pasting mechanism for forming the closed bag bottom 39. This mechanism includes the rotary, bottom-folding and pasting devices 40 and discharging rollers 41 which are driven in timed relation with the other parts of the machine.

The driving shaft 42 is driven from any desired source of power and drives the shaft 43 supporting the roller 38 through gearing 44. The shaft 43 operates the cam roller shaft 27 through a chain 45, the twoshafts operating at the same speed.

The striker bar operating shaft 21 is driven through gearing 46 from the power shaft, and the feed roll shaft 24 is driven through change speed gearing 47-.

To adapt the machine for making different sizes of bags it is only necessary to remove the cam rollers 26 and substitute therefor other cam rollers having a periphery equalto the length of the bag blanks desired. At the same time the gearing 47 is changed to speed up or slow down, as the case may be, the feed rolls 22 and 23 to produce a corresponding change in speed of the paper through the machine in accordance with the change in the size of bag being made.

It will be apparent that the invention can be variously modified and changed within the scope of the appended claims.

I claim:

1. A machine for forming envelope bags from sheet material comprising means for treating the material to form a bag tube having creases at longitudinally spaced intervals, and means for forming bag blanks by severing the opposite sides of said tube and tearing the material along said creases.

2. A machine of the character described comprising mechanism for forming and feeding a bag tube, means for creasing the fibers of said tube at longitudinally spaced intervals, and means for forming bag blanks from said tube by severing the opposite sides thereof and tearing the edges along said creases.

3. A machine of the character described, comprising mechanism for forming and feeding a bag tube, means for creasing the side edges of said tube at longitudinally spaced intervals, and means for striking off bag blanks from said tube by transversely cutting the opposite sides thereof and tearing the edges of said tube longitudinally along said creases.

4. A machine of the character described comprising mechanism for forming and feeding a bag tube, intermittently effective mechanism for creasing the material forming the side edges of said tube at longitudinally spaced intervals, and means for forming bag blanks by cutting the opposite sides of said tube and tearing the edges thereof along said creases.

5. A machine of the character described comprising mechanism for forming and feeding a bag tube, means for intermittently engaging the edges of said tube to crease said edges at spaced intervals, and means for forming bag blanks by cutting the opposite sides of said tube along longitudinally offset lines and tearing the edges along said crease to connect said lines of cut.

6. A machine of the character described comprising mechanism for forming and feeding a bag tube, rollers adapted to intermittently engage the edges of said tube to crease said edges at spaced intervals, and means for forming bag blanks by cutting the opposite sides of said tube along longitudinally offset lines and simultaneously tearing the edges of said tube along said lines of crease.

7. A machine of the character described comprising mechanism for forming and feeding a bag tube, rotary creasing mechanism for creasing the opposite edges of said tube at spaced intervals including a vertically adjustable cam roller, and means for forming bag blanks by cutting the opposite sides of said tube and tearing the edges along said creases.

8. The combination in a bag making machine, means for creasing the side edges of a bag tube at spaced intervals including a supporting roller for the edge of said tube and a creasing roller cooperating therewith having a circular periphery constantly engaging the periphery of said supporting roller and a cam surface for intermittently engaging the edge of said tube to form longitudinally spaced. creases therein.

9. The improvement in the art of making bags from sheet material which consists in manipulating a continuously advancing web of sheet material to form a bag tube having the material thereof formed with longitudinally spaced creases, severing the tube transversely and tearing the material along said creases to provide bag blanks having extended flaps.

10. The process of making paper bags which consists of forming a bag tube, creasing the edges of said tube at spaced intervals, cutting the opposite sides of said tube along longitudinally offset transverse lines and simultaneously tearing said edges along said creases to connect the ends

Images