US2346191A - Bag making machine - Google Patents

Description

April 1 c. F. SCHULTZ E TAL i 2,346,191

BAG MAKING MACHINE Filed Feb. 17, 1940 2 Sheets-Sheet 1 Q 0Q N Q INVENTORS, w CHARLES E 501w. rz;

IRA E. SCHUI. rz. g Q BY pri111,'1944. c. F. SCHULTZ Em 2,346 191 BAG MAKING MACHINE INVENTORST CHARLES E SCHuL TZ. IRA E. SCHULTZ.

ATTOR f Patented Aprrll, 1944 'UNlTED STATES PATENT OFFICE BAG MAKING mom Charles F. Schultz and Ira E. Schultz,

Oakland, Calif.

Application February 17, 1940, Serial No. 819,486 23Claims. (Cl. 93-8) The present invention relates to improvements in bag making machines, and its principal object is to provide a machine of the character described that is fully automatic and makes bags from a continuous roll of Cellophane or similar materialwhich can be sealed by the mere application of heat; under pressure.

More particularlyit is proposed to provide a machine in which a ribbon of Cellophane is fed from a roll disposed at the rear end of the machine, is periodically advanced, by means disposed at the front end of the machine andis subjected to various bag-forming operations intermediate the feed roll and the advancing means.

It is further proposed in the present invention to provide certain improvements in the feed roll mounting whereby the latter may be readily centered with respect to the machine and is allowed free rolling action during the periods of advance. while automatically operating means are providted for stopping rotation during the periods of res It is further proposed to provide means for turning the advancing ribbon into tubular form and to provide an auxiliary means for creasing the advancing material at opposite edges where a square bag is desired.

It is a. further object of our invention to provide certain improvements in connection with the cutting apparatus whereby a previously formed bag is separated from the ribbon and the new end thereof is folded over the remainder of the tubular ribbon to provide a new bottom for the next bag.

It is further proposed to provide a movable ically retracted so as to allow of sealing operations.

and the novel features thereof will be fully set forth in the claims hereto appended.

The preferred form of our invention is illustrated in the accompanying drawings, in which: Figure 1 shows a side elevation of our machine with the near side of the frame removed;

Figure 2, a front view of our machine;

Figure 3, a transverse section taken along line 3-801 Figure 1;

Figure 4, a detail view in longitudinal section illustrating the heater operating means;

Figure 5, a detail view of the s'amemechanism as seen from line 5-5 of Figure s;

Figure 6, a detail view in longitudinal section illustrating the cam drive for the cutter; and

Figure 7, a fragmentary section illustrating an eccentric drive for the advance means; and

1 template over which the extreme end of the ribbon is turned and which thereafter is automat' It is further proposed to provide separate heating means for the transverse seam at the bottom of the bag and the longitudinal seam,

the said heating means being separate to accommodat the template previously mentioned,

4 when in retracted position..

A further object of our invention is to provide certain improvements in the advancing means for the ribbon and in the gripping means for the latter and to provide a general organization in which most of the essential moving parts are driven from a common shaft whereby the machine is rendered comparatively simple.

Further objects and advantages of our inven-' tion will appear as the specification proceeds.

.dle 1''.

Figure 8, a sectional detail view taken along line 8-3 of Figure 1, and

Figure 9, an enlarged sectional detail view of the gripping means of our invention.

While we have shown only the preferred form of our invention, we wish to have it understood that various changes or modifications may be made within the scope of the claims hereto attached without departing from the spirit of the invention.

The frame i of our machine, preferably comprises two sides 2, only one of which is shown in Figure 1, the sides being supported on legs 3 and held in spaced and parallel relation by suitable spacers i. At the rear end of the machine are provided uprights 5 and the latter have arms -6 projecting rearwardly therefrom for supporting a horizontal shaft 1 on which the roll 8 of Cellophane or similar material is mounted.

The shaft 1 is supported in notches 9 in the arms 6 and one of the notches is threaded to receive a correspondingly threaded section of the shaft so that the latter may be adjusted in it position in the notches by a turning movement of the shaft'for effecting proper centering of the roll with respect to the remainder of the machine. The threaded portion of the shaft is made revolvable relative to the remainder of the shaft.- :A suitable construction for this purpose is shown in Figure 8 where the threaded portion is furnished by a sleeve 1 having a hanand held against axial motion between the brake drum I! and the head .of a bolt l'i'threaded into the end of the shaft 1.

The ribbon of Cellophane is drawn from the roll as indicated in dotted linesjlrst underneath a horizontal roller N0 of a swinging frame ll The sleeve is revolvable on the shaft being limited The-roll of Cellophane has a brake drum l1 associated therewith and a brake shoe l8 pivoted, as at [9, is adapted to bear on the brake drum to arrest movement thereof. A rod 20 connects the free end of the brake shoe with the frame ll near the pivot l2 thereof, the rod having sliding connection with the frame as at 2|, and in outward movement by a cotter pin 22. I

The frame ll extends slightly beyond the pivot, as at 23, and this extension is connected to an intermediate portion 24 of the rod 20 by means of a spring 25. With the ribbon in a position of rest, the various parts occupy the positions indicated in Figure 1. When the ribbon is advanced by the gripping means, it first tends to lift the roller it of the frame I I, which allows a short portion of the ribbon to advance. The lifting of the roller ill causes the rod 20 to be raised by the means of the cotter pin 22 which releases the brake so that the roll is free to rotate.

When the advance movement of the ribbon ceases, the roll continues to rotate, but the slack in the ribbon created by the continued rotation is taken up bythe roller III on the frame Ii,

' which immediately descends under the influence of the spring 25, which latter also pulls downwardly on the free end of the brake shoe through the rod 2| for setting the latter.

The free sliding connection between the frame H and the rod 20 allows the latter to go somewhat beyond the cotter pin 22 when the brake The front of the bar 38 is preferably provided with lateral arms 39 to furnish a better support for the front edge of the forming plate. I The rear end of the lower member of the forming plate is made to flare upward, as at 40, to guide the central portion of the ribbon underneath the forming plate.

The ribbon which is identified by the numeral 8', is sufllciently wide for folding over the forming plate to provide centrally overlapping margins and to additionally provide material for the creases to be formed in the sides .of each bag.

The creases are formed by the plates 4| supported on brackets 42, which latter again are supported on transverse rods 43. A pair of brackets are supported on each rod 43, one for each plate 4|, and the brackets are made to move along side of the rod in opposite directions by means of reverse threads 44.

Each plate has two brackets 42, one for each shaft 43, and the two shafts are interconnected by the chain drive 45. A hand wheel 46 is pro- 4 vided for one of the shafts 43, and it will be readily positively held against rotation during each period of rest.

The forming plate l4 extends lengthwise over the machine and may be made as a single plate if an ordinary tubular bag is desired. In the preferred form, shown in the drawings, which is intended for making square bags, the forming plate is made of two spaced members ll and Si held in spaced relation by a central longitudinal bar 22, this construction providing lateral grooves 33 in the forming plate. Any other suitable construction may, of course, be substituted for the one shown and'described as long as it performs the desired function.

The forming plate is supported, preferably insuch a manner as to bring the grooves substantially into alinement with the upper ends of the sides 2 of the frame, which latter are provided with inwardly-turned flanges 24. The rear end of the forming member is hinged, as at 3!, to a frame 24 suspended from the shaft 21 provided in the upper end of the uprights 5. The front Portion of the forming plate is'supported on a bar 22 having its front-end pivoted on one of the spacers 4'and having its rear end resting on the second-spacer 4 provided rearwardly of the first one. The second spacer is preferably mountseen that the two creasing plates 4|, may be moved toward one another for entering the grooves 23 of the forming plate or away from one another for removal from th grooves by the mere operation of the hand wheel 48.

Overlying the forming plate, 'We provide a heater frame 41, substantially coextensive in length with the'forming plate, and having its rear end ivoted to the frame 36, as at 48. A spring 49 has a tendency to draw the heater frame upward, but the latter is normally held against the tension of the spring with its front section in substantially parallel relation to, and slightly spaced from the front section of the forming plate, as shown in Figure l.

The rear section of the heater frame supports. on a yielding bracket 50, two rollers 5|, which ride-on the folded margins of the ribbon of Cellophane, and are arranged at a slight angle so as to have a tendency of urging the two margins toventional character may be provided, of course. to cause the advancing ribbon of Cellophane to form itself around the, forming plate into the shape ora tube,.withoverlapping margins over the center of the forming plate.

A yielding horizontal finger 54' carried by the bracket I0, is used for guiding one of the margins to fold underneath the other.

For initiating operation of the machine, the

ribbon is guided manually underneath the forming plate, with the plates 4| retracted. The side edges of the Cellophane are then folded over the" forming plate whereupon the plates 4i are moved ed eccentrically with respect to a supporting bar inwardly to enter the grooves 33 and to form the lateral creases in the ribbon. The extreme margins are folded over the edges of the forming plate manually, and are smoothed into the overlapping position shown in Figure 3. During this manual initial positioning of the ribbon, the heater frame should be allowed to swing upward and the latter is now brought down to the working position of Figure 1, with the, rollers 5| riding -on the margins of the Cellophane and the transverse bar 52 smoothing and flattening the overlap.

After the Cellophane has been thus positioned, the intermittent advance of the same is taken care of by the swinging frame i 6 and the gripping means I! carried thereby. The advance end of the ribbon at the'front end of the forming plate is formed into a bottom seam for the bagduring each operation by means to be'described hereafter, and the gripping means take hold of the bottom seam thus formed and through the lattel, pull the entire ribbon forward by' the length of one'bag, whereupon the latter length is separated from the ribbon by the cutting means to be describedlater, to allow a new seam to be formed for the next bag,

The swinging frame I6 is pivotally mounted on a sleeve 55 supported in the bearing 58 at the lower front end of the machine. It is operated to swing toward the machine and away from it by means of a link 51 pivoted to the frame, as at 58, and to an arm 59, as at 6B.

The arm 59 projects from a sleeve 6! revolvable on a transverse shaft 62, the sleeve having a short arm 83, which is rocked through the connecting rod 64 by an eccentric d on the main drive shaft I The arm 59 is formed with a slot 61 in which the pivot 50 engages and this slot is curved in such a manner that no matter at what point the pivot 80 engages therewith, the back swing of the frame l6 will always terminate at the same point with respect to the'front edge of the machine, while the forward sw ng. away from the machine may be varied to any desired degree. Thus it is impossible for an operator-to make any adjustment which would cause the frame It on its back swing, to strike the front face of the machine and to thereby cause all operations to stop.

For gripping the bottom end of the bag at the front end of the ribbon, we provide the two gripping fingers or plates 61 and 8! pivoted in the upper end of the swinging frame, as at 65 and 19, so that one finger overlies the other in gripping relation relative thereto. Each finger has an arm H projecting downwardly on opposite sides of a vertical rod I2 and the arms 'Il termnate in rollers I3 bearing on opposite sides of the With the shaft 65 rotating counterclockwise, it

will be noted from the position and shape of the cam, that the position of the rod 12 will remain substantially the same during the first quarter of a revolution; that the rod will be pulled down ward for causing the gripping fingers to close upon one another during the second quarter of the revolution and will retain the gripping fingers inthat position during the third quarter of the revolution, while the spring 83 will move the rod 12 upward for opening the gripping fingers dur ing the last quarter of the revolution.

The operation of the gripping means is t'med to correspond to the operation of the swinging frame supporting the gripping means, and the gripping fingers are made to drop the bagjust before, the frame reaches the end of its forward swing. Slight variationsin the timing of the gripping means may be brought about by raising and lowering of the pivot 89 by means of an eccentric mounting indicated in the drawing.

After a completed bag with the tra ling ribbon has been advanced by the gripping device, by the intended length of one bag, the projecting bag is separated from the ribbon by the cutting means which may be described as follows:

A stationary cutter blade 90 is mounted transverselv over the front edge of the machine at an elevation slightly higher than the forming plate It with its rear forming the cutting edge. The movable cutter 9| is mounted for reciprocating motion in a substantially vertical plane for 00- action with the rear edge of the stationary blade in cutting through the ribbon of material.

The movable blade is carried by the frame 92 supported at the forward end of abell crank lever 93 pivoted in the main frame, as at 94. The

.rear end of the bell crank lever is actuated for cutting action by a spring 95, and for reverse movement, by a cam e on the main shaft65, the cam being shown in part in Figure 1 and in full in Figure 6. j

The movable cutter blade 9| is pivoted in the frame 92, as at 96, a spring 91 urging the movable blade toward the stationary blade, and a set screw 99 serving to correctly position the movable rod, the arms being pulled toward one another by a spring 76.

The rod 12 terminates at its upper end in a cam 15, and it is apparent that when the rod is moved downward, the cam 18 enters between the rollers 13 forcing the arms ll apart and the gripblade so that it will just clear the stationary blade,- on the upward movement of the former.

It will be seen that in this manner the movable cutting blade can be adjusted with respect to the stationary blade with great precision. The

' movable cutting blade is formed with a slant from pin'g fingers I and 88 upon one another. The

points of the gripping fingers may be covered with suitable gripping material indicated at H,

The rod 12 is operated, through the cam a on the main drive shaft 5, through thefollowing mechanism, see Figures -1 and 2. The lower end hi the rod is pivoted to the horizontal arm 18 of a bell crank lever 19 pivoted to theframe, as at and having a vertical arm 8| projecting into I. slot 82 in the sleeve 55. A spring 83 in said slot tends to move rod 12 upwardly and motion in the opposite direction is imparted through a slidable pin 84 driven by one arm of a second bell crank lever 85 pivoted in the frame, as at 8B, the latter bell crank lever being operated by a vertcal rod 81- in the main frame, which is acted on by a third bell crank lever I. pivoted in the main frame, as at 99, and operated by the cam a. on themainshaft". 'i'

' This projecting portion of the ribbon is now folded-over the template by the hooked finger I00, 7

which is pivoted in the frame, as at I01, and which is acted onby a spring I02 to normally occupy a position'where it leans against the rea face of the movable cutting blade 9|. I

As soon as the cutting action is completed, a .cam I03 fixed relative to the finger I00, strikes one of the flanges 34 and causes the finger to turn over the front edge of the forming plate for folding the projecting end of the ribbon over the template 99. j

In this manner the cutting and folding is done by a relatively simple mechanism operated by r single main cam. It should be noted that the cam is used for retracting the cutter, while the spring 95 is relied on to produce the cuttins action so that in case of accident, as for instance, by the operator getting his finger caught between the cutting blades, the spring will yield and no serious injury will result.

The template 9! is a plate mounted transversely over the front section of the forming plate and is actuated by means of two vertical pins lli extending loosely through the plate and forming part of a bell crank lever I" pivotally mounted on a transverse shaft M1. The other end of the bell crank lever is actuated by the cam b on the main shaft 65 for normally holding the template in retracted position and for advancing the same toward the front ed e of the forming plate for the folding operation.

After the cutting and folding operations have been completed and the template has been retracted, the heaters carried by the heater frame become active. It will be remembered that at this time, the ribbon of Cellophane is folded about the forming plate in a manner illustrated-in Figure 3 with side creases formed by the plates ll and marginal portions overlapping substantially on the longitudinal center-line of the forming plate. A projecting end of this ribbon has been turned over backwards over the template 99 and the latter has been retracted to clear the fold, which will become the bottom of the next bag. At this time, the heater frame is made to come down to apply heat and pressure to the bottom seam and to a spaced section of the longitudinal seam, the pacing being mad necessary to accommodate the template in its retracted position.

The heater frame carries, at its extreme end, and overlying the bottom seam, a transverse heater H0, and spaced therefrom a second heater l H arranged over a portion of the longitndinal seam. Since, due to this construction, there is a break between the transverse heater and the longitudinal heater, which would leave a small portion of the longitudinal seam adjacent the bottom seam unsealed, we make the longitudinal heater sufiiciently long to seal at least a portion of the next bag. This offers the advantage that the advance portion of each bag reaches the front edge of the heater frame with its longitudinal seam already sealed, which not only facilitates the folding operation, but also produces a more perfect bottom seam, since without the pre-sealing of an advance portion, a small section of the longitudinal seam would remain unsealed in view of the fact that a small portion of the seam has to be made to project beyond the farming plate to furnish a pping edge for the ripping means. a

The heater frame 41, which is hinged at its rear end, as at 48, is operated by two rods H2, see Figures 4 and 5, rising from a transverse bar H3, which latter has two downwardly projecting lugs ill, slotted as at Hi, to straddle the main shaft '5 on opposite sides of a cam c adapted to bear down on a roller H8 supported in the lugs underneath the cam. A thecam rotates, itv

forces the heater frame downward upon the forming plate and the interposed seam of the Cellophane, while the heater frame is raised by the heavy spring I! when the cam releases its downward pressure.

A very simple way of connecting the rods H2 to'the heater is illustrated in Figures 4 and 5. The heater frame has arms H1 projecting therefrom in opposite directions and these arms are formed with notches III in them: edges, the notches being positioned for engagement by the rods H2, which latter are formed with heads HQ bearing on the upper faces of the arms H1 when properly positioned. The lugs I II have a small bracket III projecting rearwardiy therefrom andthisbracketisactedonbyaspring III tourgetherods Hlforwardly. This construction makes the attaching and de-. taching of the heater frame to and from its op erating mechanism very simple. The drawings show the heater frame attached in working pontion. To detach the frame, it is merely necessary to pull the head m of the rod H2 backward, to clear the notches H8. The spring 49 will then lift the heater frame into an out-of-the-way position. To re-attach the frame, it is pressed downward, while the rods H2 are pressed rearward to bring the rods opposite the notches Ill, whereupon they are made to enter the notches, which completes the attaching operation. The spring i2l continuously urges the rods I I: forward and prevents accidental disengagement. The plates 4| are provided with suitable slots I22 to accommodate the rods I I2.

The operation of the machine may be briefly described as follows:

In the position shown in Figure l, a cutting operation has been completed and the hooked finger I00 has turned a projecting end of the ribbon of material over the template 99. The next steps include the retracting of the template, the downward movement of the heaters to seal the bottom seam and the longitudinal seam and the downward movement of the cutter frame 92. Thereupon the gripping means l5 moves backward underneath the stationary cutter and into engagement with the forward end of the bottom ger I00 folds the projecting end of the ribbon of material over the template to prepare a new seam ready for sealing.

The individual movements of the various parts of the machine may be readily traced as follows: The five cams a, b, c, d and e are mounted on the main shaft in'the order indicated by the. letters, the cam a being adjacent the near side of the frame, as viewed in Figure 1, and cam e adjacent the far side. The main shaft 85 rotates counter-clockwise.

Taking the cams in their order, cam a operates the grippers 61-", which are shown open in Figure 1. According to the shape of the cam. they will remain open during the next quarter of revolution, will then close during the second quarter, remain closed during the third quarter;

and will open again during the last quarter.

Cam b operates the template 99 which is shown in Figure 1 as being in its front position or rather as having initiated its rearward movement. On further rotation of the cam, the rearward movement will be completed and the template will be held in its rearward position substantially through three-quarters of a revolution, whereupon it is allowed to move into advanced position for a brief period during the fourth quarter of the revo-' lutlon.

The third cam c operates the heater which is shown as having initiated its downward movement. It will be further pressed downward into as being in its most advanced position. As the cam d rotates, it pulls the swinging frame :8

, toward the work during the first quarter of the revolution, continues to pull at a decreased rate of speed during the second quarter, slowly reverses the movement during the third quarter, and swings forward to its original position during the last quarter of the revolution. It will be noted that when the gripping means reaches the seam,

it comes to a momentary stand-still while its movement is reversed. This momentary standstill coincides with the time when cam a causes the gripping fingersto close.

Cam e operates the movable cutter and the folding finger I00. The cutter is shown as hav-.

ing completed its cutting action and the folding finger as having performed the folding operation, and Figure 6 shows cam e positioned to correspond to the position of the cutting blade. 0n the next quarter of a revolution, the cutting blade will be retracted, will be held in retracted position during the second and third quarter of the revolution. and will be allowed to move back to cutting position under the influence of spring 95 during the fourth part of the revolution.

The folding finger lhlmoves as part of the cutter supporting frame and receives its final impetus to fold over the projecting end of the ribbon by the cam I03 striking the fiange 34 of the main frame. This is timed to take place immediately after the cutting action is completed.

While our machine has been described as particularly adapted for use on material such as Cellophane which may be sealed by mere application of heat under pressure, it is apparent that most of the features as readily apply to a material which requires glue or other adhesive for sealing. could be provided for feeding the glue and the heating means might be omitted from the heater frame, the latter being used as a pressure means only, or as a means for conveying a small amount of heat.

We claim:

1. In a bag forming machine, means for mounting a ribbon of material with freedom of lengthwise movement, means for forming the advance and of the ribbon into a bag, a carrier frame rookably mounted with respect to the advance edge of the bag, gripping means'carried by the frame, means for operating the frame to alternately move the gripping means toward'the advance edge of the bag and in reverse direction and means for adjusting the angle of rocking movement of the carrier frame arranged to bring the carrier to the same point on its forward swing regardless of the length of its rearward swing.

2. In a bag forming machine, means for mount.- ing a ribbon of material with freedom of lengthwise movement, means for forming the advance end of the ribbon into a bag, a carrier frame rockably mounted with respect to the advance edge of the bag, gripping means carried by the In that case any conventional means frame, means for operating the frame to aiternately move the gripping means toward the advance edge of the bag and in reverse direction,

the said operating means including a rocking shaft having an arm projecting therefrom with a curved slot in the arm and a connecting link pivoted to the carrier frame and tothe arm by means of the slot, the curve of the slot being such as to bring the carrier frame to the same point on its forward swing regardless of the adjustment with respect to the rearward swing.

3. In a bag forming machine, means for revolvablymountin'g a roll of material for feeding a ribbon of material therefrom. means engaging the front end of the ribbon for intermittently advancing the ribbon a specified distance, means for forming an intermediate portion of the ribbon into a tube during the advance, means for cutting the'ribbon at the end of each advance and at a point spaced from the front edge so as to present a new front edge means for turning the new front edge over the tube to form, a closure therefor and a common drive means for the advancing means, the cutting means and the turning means for operating the same in timed relation.

4. In a bag forming machine, means for revolvably mounting a roll of material for feeding a ribbon -of material therefrom, means engaging the front end of the ribbon forintermittently advancing the ribbon a specified distance, means for forming an intermediate portion of the ribbon into a tube during the advance, means for cutting the ribbon at the end of each advance and at a point spaced from the front edge so as to present a new front edge, a bar extending transversely across the width of the ribbon so as to rest thereon, means for intermittently moving the same lengthwise of the ribbon between an advance position near the front edge of'the tubeand a retracted positionparallel therewith, and

means for turning the new front edge over the advancing bar to form a closure for the tube.

5. In a bag forming machine, means for revolvably mounting a roll of material for feeding a ribbon of material therefrom, means engaging the front end of the ribbon for intermittently advancing the same a specified distance, means for forming an intermediate portion 01' the ribbon into a tube during the advance,- with overlapping longitudinal edges, means for cutting the ribbon at the end of each advance and at a point spaced from the front edge so as to present a newv front edge, a bar extending transversely across the width of the ribbon so as to rest thereon,-means for intermittently moving the same lengthwise of the ribbon between an advance position near the front edge of the tube and a retracted position parallel therewith, means for turning the new front edge over the advanced bar to form a transverse closure for the tube, two heating elements, one being transverse and one longitudinal, and means for pressing the same upon the turned front edge and the, longitudinal overlap for sealing the same when the bar is retracted, the heating elements being spaced by a distance equal at least to the width of the bar so as to accommodate the latter therebetween.

6. In a bag forming machine, means for revolvably mounting a roll of material for feeding a ribbon of material therefrommeans engaging the front end of the ribbon for intermittently advancing the same a specified distance, means for forming an intermediate portion of the ribbon into a tube during the advance, with overlapping longitudinal edges, means for cutting the ribbon at the end of each advance and at a point spaced from the front edge so as ,to present a new front edge, a bar extending transversely across the width of the ribbon so as to rest thereon, means for intermittently moving the same lengthwise of the ribbon between an advance position near the front edge of the tube and a retracted position parallel therewith, means for turning the new front edge over the advanced bar to form a transverse closure for the tube, two heating elements, one being transverse and one longitudinal, and means for pressing the same 7 termittently advancing a ribbon of material for bag-forming operations, a heating device mounted over the ribbon with freedom of swinging movement in the vertical plane of the ribbon, means urging the heating device away from the ribbon, a transverse shaft underneath the ribbon having a cam thereon,- a forked member straddling the cam, and having slots in which the shaft is slidably received, a roller at the end of theforked member for the cam to operate against, a transverse member carried by the forked member and having prongs projecting upwardly therefrom, arms projecting from the heating device having notches'therein for receiving the prongs, and spring means urging the prongs into the notches, the prongs having heads bearing down on the margins of the notches.

8. In a bag forming machine, means for intermittently advancing a ribbon of material for bag forming operations including means for folding the same to form a tube, a stationary cutter mounted over the tube, a movable cutter mounted imdemeath the 'tube for ooaction with the former cutter in cutting the tube, means for moving the movable cutter, a bar, means for moving the same to overlie the tube near the cutters, a folder carried by the movable cutter so as to move therewith and means on the folder cooperable with a fixed member for swinging the folder around the Ear for folding the cut end of the tube over the 9. In a bag making machine, a mandrel having a front edge substantially fitting within a bag to be made, means for advancing material over movement, means for cutting the sleeve .at a

point spacedslightiy from the front edge'of the mandrel so as to leave a small projecting portion of the sleeve in front of the mandrel free for A 11. In a bag making machine, a mandrel,

means for mounting the same horizontally with freedom of slight vibratory movement of the front section of the-mandrel, a supporting element for the front section of the mandrel, means for advancing material ovr the mandrel in inthe mandrel from the rear in intermittent movement to form a sleeve embracing the mandrel" and extending forwardly therefrom substantially by the length of a bag at the end of each movement, means for cutting the sleeve at a Point spaced slightly from the front edge of the man-- drel and extending forwardly therefrom substantially by the length of a bag at the end of each-- termittent movement with a thickness of material between the mandrel and the supporting element and overlapping side margins on top of the mandrel, a heater, means for pressing the same upon the overlapping side margins for sealing the same, whereby the mandrel is pressed upon its supporting element, the advancing means being constructed to exert a slight upward pull on the sleeve for relieving the pressure, on the thickness of material confined between the mandrel and the supporting element.

12. In a bag making machine, a mandrel, means for mounting the same horizontally with freedom of slight vibratory movement of the front section of the mandrel, a supporting element for the front section of the mandrel,

means for advancing material over' the mandrel in intermittent movement with a thickness of material between the mandrel and the supporting element and overlapping side margins on top of themandrel, a heater, means for pressing the same upon the overlapping side margins between the mandrel and the supporting means.

a bar extending transversely across the plate'to I aid in forming the bottom seam and being retractable to an inactive position, and a heating means for the seams comprising a supporting bracket, a heater arranged transverselythereon for sealing the bottom seam and a second heater mounted longitudinally thereon for sealing the longitudinal seam, the second heater being spaced from the first heater to allow clearance for the retracted bar.

14. In a bag making machine, a frame, means for revolvabl; mounting a roll of material thereon for feeding a ribbon from said roll, a mandrel arranged longitudinally with respect to the ribbon and having lateral grooves therein, means -for passing an intermediate portion of the ribbon over the mandrel to form atube, creasin plates adapted to project into the grooves from opposite sides, a pair of shafts extending transversely across the frame, a pair of brackets on each shaft for supportingthe' creasing plates, reverse threads on each shaft for driving the brackets toward or away from each other, and adriving connectlonbetween the two shafts.

15. In a bag making machine, a mandrel adapted-to, have a bag. formed thereommeans fox-horimntally mounting the mandrel, shaft mounted below the mandrel, a frame having a pivoted support at its lower end below the front end of the mandrel and having an upper end rockable toward and away from the' front end of the mandrel, gripping members carried by the upper end of the frame, means for operating the gripping members including a cam rod and a member slidable in co-axial relation to the frame, means operated by. the shaft for rocking the frame,

said end, means for operating the gripping members including a member slidable in co-axial relation to the frame, a revolvable shaft, a driving connection between the haft and the frame, and

a driving connection between the shaft and the slidable member, whereby the gripping members are made to act in timed relation to the frame movements.

. 1'7. In a bag making machine, a mandrel adapted to form bags thereon from a continuous ribbon, means engaging the front end of the ribbon for intermittently advancing the same a specified distance, the said means including a pair of gripping members, a movable carrier for the same and means for operating the carrier and the gripping means in timed relation whereby gripping means release the front end of the ribbon before the carrier reaches the end of its movement; I

18. In a bag making machine, a mandrel adaptedto have a ribbon of sheet material arranged thereon in tubular form, means for intermittently advancing the material, means for cutting the material a short distance ahead of the mandrel to leave a projecting portion, meansfor folding the projecting portion over the mandrel, and means for operating the cutting means and the folding means in automatic succession.

19. In a bag forming machine, a mandrel adapted to have a ribbon of sheet material arranged thereon in tubular form, means for intermittently advancing the material, a cutter blade mounted above the ribbon slightly forward of the mandrel, a lever mounted underneath the mandrel and having a second cutter blade for cooperation with the first blade in cutting the ribbon so as to leave a portion projecting beyond the mandrel, and a folder carried by the lever for cooperation with a fixed element in folding the projecting portion over the mandrel.

20. In a bag making machine, a mandrel adapted to have a ribbon of sheet material arranged thereon in tubular form, means for-intermittently advancing the ribbon, a bar extending transversely across the mandrel so as to rest on the ribbon and being made to project beyond the sides of the mandrel, and means engaging the projecting ends of the bar for sliding the bar back and forth over the material in timed relation to the intermittent advanceimovements,

21. In a bag forming machine, a mandrel, means for folding sheet-like material about the mandrel in tubular form, means for mounting the mandrel horizontally with a slight vibratory movement of the front section of the same, a

1 supporting element for the front section of the mandrel, a heater, means forintermittently pressing the same upon the material for sealing the same whereby the mandrel is pressed upon the supporting element, and means for advancing the sheet material after each heatingoperation with a slight lifting effect for relieving the pressure on the material confined'between the mandrel and the supporting element.

22. In a bag making machine, a mandrel adapted to have sheet-like material folded thereabout in tubular form with overlapping edges on top of the mandrel, means operable for intermittent- 1y advancing the material a specified distance, means adapted for cutting the material a slight distance forward of the mandrel after each advance and for folding the projecting portion of the material over the front edge of the mandrel to form an overlap, means adapted for heat-sealing the overlapping portions of the sheet material, and means for operating the advancing means, cutting and folding means, and the heatseallng means in timed relation.

23. In a bag making machine, a mandrel adapted to have sheet-like material folded thereabout in tubular form with overlapping edges on top of the mandrel, means operable for intermittentlyv advancing the material a specified distance, means adapted for cutting the material a slight distance forward of the mandrel after each advance and for folding the projecting portions of the material 'over the front edge of the mandrel to form an overlap, means adapted for heat-

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