US3671033A

US3671033A - Machine and method for folding plastic bags and the like

Info

Publication number: US3671033A
Application number: US92087A
Authority: US
Inventors: John B Coast
Original assignee: Coast Machinery Inc
Current assignee: Glad Products Co; Coast Machinery Inc
Priority date: 1970-11-23
Filing date: 1970-11-23
Publication date: 1972-06-20
Anticipated expiration: 1989-06-20
Also published as: FR2115956A5; DE2157593B2; CA948662A; GB1362594A; DE2157593A1

Abstract

An automatic, variable speed, plastic-bag-folding machine which takes flat plastic bags, rolls, folds, flattens and packages the bags; the machine consists of a conveyor belt assembly (FIGS. 1 & 2) fed by the discharge of a plastic-bag-making machine which feeds the bags into rolling, folding (FIGS. 6 & 7) and multi-bag packaging sections (FIG. 8), synchronized by a pneumatic control system (FIG. 9); the preferred embodiment produces the tubular, rolled bag by a circularly disposed set of interdigitated rollers (FIGS. 3-5); a second embodiment utilizes a continuous belt having a geometric circular rolling section therein to produce the tubular rolled bag (FIGS. 10 & 11).

Description

United States Patent Coast 51 June 20, 1972 [541 MACHINE AND METHOD FOR FOLDING PLASTIC BAGS AND THE LIKE [72] Inventor: John B. Coast, Baton Rouge, La.

[73] Assignee: Coast Machinery, Inc., Baton Rouge, La.

[22] Filed: Nov. 23, 1970 211 Appl. No.: 92,087

2,775,410 12/1956 2,526,010 10/1950 3,228,620 l/1966 Lee ..242/66 X Primary Examiner-George F. Mautz Assistant Examiner-Edward J. McCarthy AttorneyC. Emmett Pugh [57] ABSTRACT An automatic, variable speed, plastic-bag-folding machine which takes flat plastic bags, rolls, folds, flattens and packages the bags; the machine consists of a conveyor belt assembly (FIGS. 1 & 2) fed by the discharge of a plastic-bag-making machine which feeds the bags into rolling, folding (FIGS. 6 & 7) and multi-bag packaging sections (FIG. 8), synchronized by a pneumatic control system (FIG. 9); the preferred embodiment produces the tubular, rolled bag by a circularly disposed set of interdigitated rollers (FIGS. 3-5); a second embodiment utilizes a continuous belt having a geometric circular rolling section therein to produce the tubular rolled bag (FIGS. 10 & 11).

Having formed the rolled bag, a vertical pin located at the middle of the tubular bag is thrust perpendicular to and against the tubular roll pulling the flexible bag from the rolling section and producing a half-fold; as the bag is pulled from the rolling section it is passed between two inwardly biased rollers to flatten the bag and then pushed into the multi-bag packaging section consisting of a tightly fitted pin slot on a set of conveyor chains which holds and secures the folded bag as the pin is retracted in preparation for the next bag folding cycle; when the appropriate number of bags have been folded and secured, a commercial packaging box is fitted beneath the loaded slots and a set of fingers are activated to push the bags out of the slots into the box.

20 Claims, 1 1 Drawing Figures PATENTEDJUH 20 4972 SHEET 2 OF 6 .mm 09 0Q .m mm 1 5 mm mm INVENTOR. JOHN B. COAST AT TOR NEY P'ATENTEnJuuzo m2 3,671,033

saw 3 0F 6 'INVENTOR. JOHN B. COAST ATTORNEY P'ATENTEDJum I972 SHEET 6 BF 6 INVENTOR. JOHN B. COAST 5W ATTORNEY PATENTEDJUHO I972 SHEE T 5 0F 6 INVENTOR.

JOHN B. COAST Mall/ll l l n I I I I I l I l l I l :2

ATTORNEY AIR SUPPLY LINE P'A'TE'N'TEDmzo 1912 3, 71,033

sum 6 or e INDEX CYLINDER UNLOAD CYLINDER INVENTOR. JOH N B. COAST BY Q'J'MW ATTORNEY MACHINE AND METHOD FOR FOLDING PLASTIC BAGS AND THE LIKE BACKGROUND OF THE INVENTION The present invention relates to a bag-folding and packaging machine specifically and particularly designed to handle sheet or flat plastic materials such as are used for plastic bags, although other equivalent sheet materials may be processed. The function of the machine is to receive the discharged bags from a bag-making machine at any given rate and to automatically process, fold and package the bags so that they are ready for commercial distribution.

In the past few years great studies have been made in the production of plastic materials and the acceptance of plastic versions of products over older versions of products made from other materials. A dramatic example of this has been the great demand for and acceptance of plastic bags for garbage and food wrapping over the standard paper bags.

The drastic physical difierences between cellulostic product or paper bags and plastic bags have opened up new marketing frontiers for the plastic bag manufacturing industries,particularly in refuse bag production.

While not directly influencing the overall volume of solid waste or methods of solid waste disposal, the recent upsurge of plastic refuse bags has, in comparison to metal cans, made possible cleaner, odorless, noiseless removal of garbage. In addition, certain economic advantages are offered by fewer manhours for maintenance and collection, no scrubbing of cans and less costly pick-up or collection trucks.

Other advantages include: air and water tight plastic bags eliminate messy pick-ups; there is less attraction for diseasecarrying insects and rodents; less storage space is needed than is required for garbage can storage; injuries are reduced with lighter weight sacks; and no empty cans remain after curb pick-up. Regardless of the method used for garbage collection in our American life style, the plastic refuse bag should serve an increasingly major role in the ecology of our environment, thereby increasing the already present need for a plastic-bagfolding machine.

These plastic bags are made of film forming polymers such as polyethylene, polypropelene and polyvinylchloride. In comparison to their paper or cellulosic counterparts, the plastic bags have substantially no structural rigidity, are thinner and have much lower surface friction characteristics. As a result of these different physical characteristics, the prior art solutions to handling and manipulating paper bags or for that matter fabric materials as well, for example, in the folding and packaging stages, have been found to be inapplicable to or unworkable with plastic bags.

The plastic bag manufacturers of today for the most part have had to end the automated process prior to the folding step simply because the inherent physical difference in materials cause impossible operating difficulties using the automatic prior art paper bag or fabric folding machines. Although many possible variations of the prior art paper bag and fabric folding machines have been experimentally tested and tried, the results have been unsatisfactory, due largely to the basic physical property differences.

The current manufacturers of bags, in an attempt to satisfy market demands, have had to revert to hand-folding and hand processing of each bag as it is discharged from the bag-making machinery, resulting in the lower production rates, less reliability and greater expense inherent in any hand or manual operation. The advantages of a completely automated process versus a semi-automated process, that is one which is dependent upon the human element for completion of one or more steps in the process, is well known and established. Complete automation of a repetitve process such as bag folding and packaging is of course highly desirable.

The present invention will replace the human element in the bag production line and lower the price per unit, so as to lower the ultimate consumer price.

Other advantages of the specific embodiment of the present invention, particularly in its rolling and folding sections, are inter alia that the rolling of the bag is inherently self-starting, there is good roll obtained by there being a moving surface winding completely around the roll forming section in which assisted by centrifugal action which produces a strong a frictional drive action. Moreover, the machine design results in easy bag removal since there is no cone or solid mandrel in the roll, as is often found in prior art machines and removal is completely achieved without stopping the surface wind rolls. To date, prototype speeds of sixty (60) cycles per minute have been achieved, and much greater speeds are possible.

Various other objects, distinctions and advantageous features of the present invention will become apparent from the description of the preferred embodiment below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a right, side view of the complete machine of the present invention, showing the conveyor belt assembly, rolling, folding and multi-bag packaging sections, the latter being partially cut away:

FIG. 2 is a top, plan view of the conveyor belt assembly, rolling, folding, and multi-bag packaging sections;

FIG. 3 is a cross-sectional, end view from the rear of the machine along sectional lines 3-3 of FIG. 2,illustrating the driving mechanism for the conveyor belts and for the bag rolling rollers, and showing the interdigitation of the rollers;

FIG. 4 is a cross-sectional, side view along section lines 4-4 of FIG. 2 of the rolling mechanism, illustrating a bag entering the rolling section;

FIG. 5 is a cross-sectional side view along section lines 5-5 of FIG. 2 of the rolling section, including the folding mechanism, and illustrating the bag completely rolled and awaiting the bisectional fold;

FIG. 6 is a cross-sectional, end view depicting the folding mechanism;

FIG. 7 is a top view of the folding unit illustrating the creasing mechanism;

FIG. 8 is an end view from the rear of the machine of the multi-bag packaging section;

FIG. 9 is a schematic illustrating using ASA standard symbols of the pneumatic control system for the machine of the present invention; 1

FIG. 10 is a cross-sectional, side view, illustrating a second embodiment of the rolling section wherein a continuous conveyor belt system is used, and illustrating a bag in the rolling section; and

FIG. 11 is a cross-sectional, front view along section lines 11--ll of FIG. 10, illustrating the belt of the second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT of eight two-inch-wide belts. The bag is held firmly between these belts and conveyed to the folding section of the machine.

As is shown in the drawings, note for example FIGS. 2-5, the closed width of the rolling section is quite substantial, that is, the length of rollers 15 is substantially greater than the radius of the circle about which the axes of the rollers 15 are disposed.

The belts 1,2 are supported by idler rolls 3 conveniently placed along the belt path as desired. Belt tension is maintained on the belts 1,2 by spring loaded tensioners 4, each belt having independent tensioners.

As indicated in FIGS. 4 and 5, the upper belts 1 are friction driven by a rubber covered upper drive roll 5, while the lower are similarly driven by a lower drive roll 6. Both upper drive roll 5 and lower drive roll 6 are driven by a conventional chain drive consisting of sprockets 7,8,9 and chain 10. Sprocket 7 is in turn driven by a DC motor 11 which provides, for example, a -400 feet per minute variable belt speed which can be easily set to match the bag-making machine output rate as presently found in the industry.

This chain drive also provides power for the right folder roll section sprocket 12. Similarly the left folder roll section is driven by means of the roll and

sprockets

13, 14. As seen in FIGS. 2 and 3, sprocket 13 is fixed to the upper belt drive roll 5 and sprocket 14 drives the left roll section, sprocket 12 being its analogous counterpart on the right roll section.

As best seen in FIGS. 4 and 5, the belt sections 1,2 feed the flat, unfolded bag into a group of intermeshing or interdigitating, driven rollers 15 whose surface interaction with the bag cause it by a positive driving action to be wound into a roll. The axes of the rollers 15 are disposed about 270 degrees of a circle, leaving an opening into the bag rolling section into which the belt sections 1,2 feed the bag. The peripheries of the rollers 15 facing inwardly into the circle thus define a generally circular moving surface which drives the bag around into a roll. Driving force is transmitted to the bag by friction between the rubber surface of the rollers 15 and the bag itself. Also the belts 1,2 push the bag into the rollers 15.

Although the axes of the rollers 15 are shown disposed in a precise circle, merely a curved disposition is satisfactory.

The rollers 15 thus form in effect a laterally and horizontally disposed cul-de-sac having an inner moving surface for driving the bag into a roll. Although, it is possible to introduce the bag into the rolling section at another angle or direction than that shown, it is particularly advantageous to introduce it at the bottom lip of the cul-de-sac so that as the bag is driven upward it has a tendency to roll back upon itself.

Centrifugal force, bag material stiffness and the increase in the bag diameter as it is being rolled contribute to the normal force which holds the bag against the drive rollers 15 surface and positively guide it to its rolled condition. The surface speed of rollers 15 is usually designed to be -30 percent greater than belts 1,2. Provided sufficient friction is maintained between the bag and drive rollers 15, the bag will completely roll up. The bag is thus changed from a large, flat sheet to a rolled cylinder, the first step in the folding process, without the necessity of a solid inner mandrel. Although the solid inner mandrel found in prior art systems is avoided in the present invention, enhanced interaction between the bag and the moving surfaces of the rollers 15 may be obtained if desired by adding a perforated tube in the interior of the circle of the rolling section to provide outwardly directed air jets, further pushing the bag outwardly against the rollers 15.

To prevent the bag from escaping between the rollers 15, the rollers 15 have alternating protruding sections 16 which interdigitate or intermesh with the adjacent rollers, as best shown in FIG. 3. This is achieved by placing alternating rubber sleeves 16 on the roll shafts as shown. The degree of interdigitation or intenneshing can be controlled by varying the sleeve width, diameter, spacing and thereby the amount of overlap or intermesh. Friction characteristics of the system can of course be varied by changing the sleeve material and hence its properties.

Although in the disclosed embodiment all the rollers 15 are driven at the same speed, their speed could be different. Particularly each roller 15 could be run at a higher speed than its immediate neighbor so that the last roller to touch the bag will be running at a higher speed than the initial roller 15.

The structural supporting plates at each end of the rolling section 15 are sectioned alonga horizontal line and hinged on pins. Easy entry is thereby allowed into the cul-de-sac defined by the rolling section 15, in case of bag jamming or any other occasion that requires access to the interior of the machine.

The inside diameter of the rolling secton 15 is directly proportional to the width of the folded bag. Therefore any change in the diameter will effect proportionally the width of the folded bag.

To guide the bag from the conveyor sections 1,2 into the rolling section, a number of guides 17 are placed between roll 18 and the initial or bottom drive roll 15; note particularly FIGS. 3-5. These guides 17 also'serve as guides for the lower belts 2. Similar to the lower guides 17, there is an upper set of guides 19 which guide the bag from the upper belts 1 into the roll section. They also serve as upper belt guides.

In order to permit the removal and flat folding of the rolled bag in a manner explained below, the rollers 15 do not extend the full width of the machine but rather are divided into two separate but interconnected side sub-sections. The central region between the central supports 150 of the side sections of the rollers 15 is basically open and unobstructed. As is shown in the drawings, note for example FIG. 2, the width of the open area 150 is substantially less than the width of the roller sub-sections, that is, less than the length of the rollers 15. As explained above, the two sections of the rollers 15 are commonly driven and so interconnected by means of drive shaft 5.

In order to protect the machine in case of bag jam-up or the like, both sections of the drive rollers 15 are driven through an overload slip clutch and sun gear drive system. As illustrated in FIGS. 2 and 3,

sprockets

12,14 drive via clutch disc 20 the main sun gear 21. Clutch clamping pressure on the clutch disc 20 is obtained by adjusting nut 22, thereby loading spring washer 23. Tightening nut 22 increases the clutch clamping pressure. Sprocket 12, clutch disc 20 and gear 21 are loaded and supported between two thrust bearings 24. The sun gear 2] drives gears 25 which are fixed to roller shafts 15' thus providing power to the rollers 15. A jam or overload will cause slippage between gear 21, clutch disc 20 and

sprocket

12, 14.

Although 270 degrees of curved rolling section 15 has been illustrated it is possible to get a rolling section with much less coverage, it being only necessary to supply sufiicient coverage so that the bag would have a tendency to fall back upon itself and form a roll as it proceeds into the rolling section.

As a normal rule it would usually require degrees of coverage to properly form a roll.

The preferred embodiment described above requires a conveyor belt assembly and, although completely integrated, a separate mechanism for rolling the bag. In FIGS. 10 and 11, a second embodiment accomplishing the conveying and rolling step using only one continuous mechanism, namely a continuous belt mechanism, is illustrated.

The continuous belt mechanism of FIG. 10 employs a lower 56 and upper 61 belt conveyor assembly similar to the preferred embodiment. However the lower belt 56, rather than immediately returning as in the preferred embodiment, is guided into a geometric circular section therein creating a rolling section 63.

A guide element 59 is positioned between the lower special belt 56 and the upper belt 61 at the entrance to the rolling section 63 to facilitate the formation of the roll and avoid the possibility of the bag following the belt out of the circular rolling section 63.

The lower belt 56 like the belts 1,2 of the preferred embodiment can consist of eight belts, each 2 inches wide and on 3 inch centers. A 4 inch opening between the two inside belts to allow the passage of the integral pin folding mechanism 26-30 as described supra should of course also be provided Although having open areas between the belt, the total closed width of each belted rolling sub-section would still be substantial, being still substantially greater than the radius of the circular rolling section.

In order to provide positive control and positioning of thelower belts 56, particularly in the rolling section 63, lateral pins 64 on the belts 56 ride in guides 59; note especially FIG. 11. The belts 56 are driven by drive roller 60 and ride on and are supported by

idler rollers

55, 58, 62.

Noting particularly FIGS. 2 and 5-7, the fully rolled bag is removed from the roller secton, folded in half and flattened in the following manner. Pin 26, which is fully retracted while the bag is being rolled, is driven down from packing gland 27 by air cylinder 28, as shown in FIG. 5. When pin 26 is fully extended, slider block 29 starts moving toward the rear of the machine away from belts 1,2 with the pin 26, gland 27 and air cylinder 28 mounted on and carried by the slide block 29. Slider 29 is driven by air cylinder 30 and slides on guide bars 29. At the same time pin 26 is coming down, flattening rolls 31 move in and flatten the bag along its centerline position, as shown in FIGS. 6 and 7. Rolls 31 are in the phantom line position (FIG. 7) during the rolling operation, and move to the solid line position while pin 26 comes down and moves past them. The movement of rolls 31 is provided by air cylinder 32 and

appropriate linkages

33,34.

As slider block 29 moves to the rear of the machine to the right in FIGS. 2 and 5, the bag is pulled between the inwardly pressing vertical rolls 31 by the pin 26, thereby flattening and transversely folding the bag in half. The bag is pulled through the rolls 31 until the tail end clears the rolls 3].

After being rolled and folded flat, the bags are assembled and packaged in the following manner, having particular reference to FIG. 8. As pin 26 pulls the bag from rolls 31, the bag is pulled between two sets of holding pins 35 which are mounted on

chains

36,37;note FIGS. 1 and 2. When the bag is fully extracted from the roll section and inserted and held between the pins 35, the pin 26 retracts and slider block 29 returns to its original position, As each bag is pulled from the rolling and folding sections, chain 36 indexes and an open set of pins 35 is brought into position to'receive a new bag. Any appropriate indexer mechanism can be used. The folded and held bags are moved by the pins 35 and

chain

36,37 from the load position described above in a counter clockwise direction (looking at FIG. 8) to a boxing section A protective shield 45 is supplied to prevent the bags from falling out of the loaded slots from the loading position to the boxing section of the packaging unit. When a desired number of bags are directly over box 38, pusher plate 39 driven by air cylinder 40, extends and pushes bags off of pins 35 into the box 38. Alternatively, instead of going into a box, the bags could be discharged into a holding mechanism or tray, as desired. From the tray the bags could be pushed into an end load box.

As illustrated,

chains

36,37 are supported by

sprockets

41, 42 & 43. Element 44 is a detent to hold the

chains

36, 37 in position while it is being indexed.

In order to control, coordinate and synchronize the various elements and sections of the machine, an appropriate control system with sensors is used. The sensing element for the control of the various air cyclinders described above could be achieved by using means such as air cams, solenoids or rotary actuators, to mention but a few. A pneumatic or air system was chosen for the preferred embodiment. An air proximity sensor 46,shown in FIG. 4, senses a passing bag. The resulting signal controls a simple, conventional sequencing pneumatic system which in turn controls all of the air cylinders described above. Such a pneumatic system is schematically illustrated in FIG. 9, standard ASA symbols being used.

The pneumatic control system operates as follows. Pressure of a passing bag is detected by fluidic proximity sensor 46. Sensor 46 outputs an air pressure increasing the pressure in line A, causing diaphram amplifier 47 to operate. Operation of amplifier 47 pressurizes line B which then causes air control valve 48 to shift. Shifting of valve 48 retracts air cylinder 28 and extends air cylinder 32.

When pressure in line C reaches approximately Psig, sequence valve 49 shifts.

Cylinders

28,32 are sized so that they will operate at less than 15 Psig or at the sequence pressure. Shifting of valve 49 causes air cylinder to retract and air cylinder 51 to extend. Extension of cylinder 51 indexes sprocket 53 which

indexes chains

35,36. Any appropriate index mechanism may be used. Cam 52 is fixed to sprocket 53. The air control valve 50, when pressure is on line D, extends air cylinder 40.

When the end of the bag passes sensor 46, pressure in line A drops, amplifier 47 returns to its original condition and line B is vented to atmosphere through the amplifier. Valve 48 is returned by an appropriate spring bias. Shifting of valve 48 causes the air cylinder 28 to extend, air cylinder 32 to retract, and valve 40 to shift when sequence pressure is reached in line F. Shifting of valve 49 causes cylinder 30 to extend to its normal position and cylinder 50 to retract to its normal position. Line D is thus vented to atmosphere through valve 49. The control system will then remain in this posture until sensor 46 senses the pressure of another bag.

In most if not all of the prior art machines using a rolling technique prior to the folding,a certain degree of rigidity of the material being folded was necessary. By using a relatively high speed conveying drive, the relatively rigid type of material such as paper could be driven into a system of static circular guides to thereby form a roll. However, plastic bag or sheet material, having practically no rigidity, does not consistently work with such prior art machines.

The present invention provides, not a static guide, but rather a guide that generates or has its own driving force. The two particular embodiments disclosed of the present invention for the rolling section, namely, a set of driver rollers circularly disposed and a continuous driven belt having a circular section, provide a positive, dynamic carrying and driving of the bag into a tubular roll. This positive, dynamic carrying and driving of the bag into a tubular roll at high speed is an important element for successful operation when dealing with low rigidity materials such as plastic bag type sheet plastic.

Other embodiments of bag rolling sections are possible, the two disclosed being of course merely exemplary.

Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the description requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.

What is claimed as invention is:

l. A folding machine for folding flexible sheet material such as plastic bags and the like comprising:

rolling means for rolling the material into a roll comprising a rolling section disposed about at least degrees of a circle, said rolling section presenting on its inward side a moving surface throughout a substantial portion of said 180 degrees of a circle, said moving surface driving the material into a roll, said roller section being divided into at least two laterally disposed sub-sections having an open, unobstructed area therebetween;

introduction means for introducing the material into said rolling means;

removal means for removing the rolled material from said rolling means, said removal means including an extended member extended in a direction at least generally perpendicular to the axis of the curved surface defined by said rolling section, the rolled material being removed from said rolling section by the extended member moving through and across said open area, moving the rolled material out of said rolling section; and

folding means for folding the rolled material as desired after it is removed fromsaid rolling section by said removal means.

2. The machine of claim 1 wherein each of said rolling subsections has a substantial width as measured along their longitudinal axes, the total width of each being greater than the radius of said circle, the width of said open area being substantially less than the width of said rolling sub-sections.

3. The machine of claim 2 wherein each of said rolling subsections are of equal width, said open area being in the middle of said rolling means and said'extended member contacting the rolled material in the vicinity of its mid-section as the rolled material is moved out of said rolling section.

4. The machine of claim 2 wherein said rolling section is a series of horizontally disposed, juxtaposed, parallel rollers whose axes are disposed about said circle to form the curved portion of said rolling section.

5. The machine of claim 4 wherein said rollers have alternating depressions and raised portions which interdigitate with the alternating depressions and raised portions of the adjacent roller(s).

6. The machine of claim 2 wherein said rolling section is a continuous, endless moving belt system which follows a curved path.

7. The machine of claim 2 wherein the linear speed of said moving surface is at least equal to the speed at which the material is introduced into said rolling means by said introduction means.

8. The machine of claim 7 wherein said linear speed is substantially greater than the speed of the material.

9. The machine of claim 2 wherein said rolling section forms a laterally and horizontally disposed cul-de-sac, the material being introduced into the cul-de-sac formed by said rolling section at its lower lip.

10. The machine of claim 2 wherein said extended member is a vertically disposed elongated finger-like pin which extends down across the full inner diameter of said rolling section as it moves across said open area.

11. The machine of claim 2 wherein said folding means comprises a pair of parallel, juxtaposed rollers which bear toward each other and are disposed adjacent to said open area, said extended member upon passing through said open area pulling said rolled material through and passed said juxtaposed rollers for folding thereof.

12 The machine of claim 2 wherein there is included preliminary packaging means adjacent to said folding means for temporarily holding a series of rolled and folded materials prior to the packaging thereof.

13. The machine of claim 12 wherein said preliminary packaging means comprises a series of adjacent, opposing pins mounted on and extending out from the periphery of a set of chains carried by a series of rotatable sprockets, said extended member carrying and depositing the rolled and folded materials into and between said adjacent, opposing pins after passing through said folding means for temporary storage.

14. The machine of claim 13 wherein said set of chains passes around and over one of said sprocket at the point where the rolled and folded material is deposited between the pins, causing the pins to be open wide at their entry portion for easy entry of the materials therein.

15. A folding machine for folding flexible sheet material such as plastic bags and the like comprising:

rolling means for rolling the material into a roll comprising a rolling section formed by two sets of a series of horizontally disposed, juxtaposed, parallel rollers whose axes are disposed about at least 180 degrees of a circle to thereby present on their inward side a moving surface throughout at least a substantial portion of said 180 degrees of a circle, said moving surface driving the material into a roll, each set of rollers having each roller parallel and in line with a corresponding roller in the other set, said sets being laterally disposed to each other but separated apart and having an open, unobstructed area therebetween;

introduction means for introducing the material into said rolling section;

removal means for removing the rolled material from said rolling section, said removal means including an extended member extended in a direction at least generally perpendicular to the axis of the curved surface defined by said rolling section, the rolled material being removed from said rolling section by the extended member moving through and across said open area, moving the rolled material out of said rolling section; and

folding means for folding the rolled material as desired after it is removed from said rolling section by said removal means.

16. The machine of claim 15 wherein the length of said rollers is substantially greater than the radius of said circle and the width of said open area being substantially less than the length of said rollers.

17. The machine of claim 16 wherein each of said sets of rollers are equal in length, said open area being in the middle of said rolling means and said extended member contacting the rolled material in the vicinity of its mid-section as the rolled material is moved out of said roller section.

18. The method of folding flexible sheet material such as plastic bags and the like comprising the steps of:

1. providing rolling means for rolling the material into a roll comprising a rolling section disposed about at least degrees of a circle, said rolling section presenting on its inward side a moving surface throughout at least a substantial portion of said 180 degrees of a circle, said roller section being divided into two laterally disposed subsections having a substantial width and having an open, unobstructed area therebetween;

2. introducing the flexible sheet material in a flat state into said rolling means, and rolling said sheet material into a roll by said moving surface driving the material into a roll;

3. providing removal means for removing the rolled material from said rolling means, said removal means including an extended member extended in a direction at least generally perpendicular to the axis of the curved surface defined by said rolling section;

. removing the rolled material from said rolling section by means of removing said extended member through and across said open area of said rolling section and thereby moving the rolled material out of said rolling section; and

5. folding said rolled material in halfas the rolled material is being removed from said rolling section and flattening the folded, rolled material after it has been removed from said rolling section,

19. The method of claim 18 wherein said rolling section is formed of two sets of a series of horizontally disposed, juxtaposed, parallel rollers whose axes are disposed about said 180 degrees, and wherein step (1) further includes driving said rollers at a relatively high speed, producing a centrifugal action forcing the material out against said moving surface, and thereby positively driving the material into a roll.

20. The method of claim 19 wherein said sets of rollers are of equal length, said open area being in the middle of said rolling means, and wherein step (2) includes introducing the material into said rolling means so that the mid-line of the material is introduced at said open area, the extended member contacting the rolled material in the vicinity of its mid-section as the roller material is being moved out of said roller section.

Claims

1. A folding machine for folding flexible sheet material such as plastic bags and the like comprising: rolling means for rolling the material into a roll comprising a rolling section disposed about at least 180 degrees of a circle, said rolling section presenting on its inward side a moving surface throughout a substantial portion of said 180 degrees of a circle, said moving surface driving the material into a roll, said roller section being divided into at least two laterally disposed sub-sections having an open, unobstructed area therebetween; introduction means for introducing the material into said rolling means; removal means for removing the rolled material from said rolling means, said removal means including an extended member extended in a direction at least generally perpendicular to the axis of the curved surface defined by said rolling section, the rolled material being removed from said rolling section by the extended member moving through and across said open area, moving the rolled material out of said rolling section; and folding means for folding the rolled material as desired after it is removed from said rolling section by said removal means.

2. The machine of claim 1 wherein each of said rolling sub-sections has a substantial width as measured along their longitudinal axes, the total width of each being greater than the radius of said circle, the width of said open area being substantially less than the width of said rolling sub-sections.

3. The machine of claim 2 wherein each of said rolling sub-sections are of equal width, said open area being in the middle of said rolling means and said extended member contacting the rolled material in the vicinity of its mid-section as the rolled material is moved out of said rolling section.

4. removing the rolled material from said rolling section by means of removing said extended member through and across said open area of said rolling section and thereby moving the rolled material out of said rolling section; and

5. folding said rolled material in half as the rolled material is being removed from said rolling section and flattening the folded, rolled material after it has been removed from said rolling section.

12. The machine of claim 2 wherein there is included preliminary packaging means adjacent to said folding means for temporarily holding a series of rolled and folded materials prior to the packaging thereof.

15. A folding machine for folding flexible sheet material such as plastic bags and the like comprising: rolling means for rolling the material into a roll comprising a rolling section formed by two sets of a series of horizontally disposed, juxtaposed, parallel rollers whose axes are disposed about at least 180 degrees of a circle to thereby present on their inward side a moving surface throughout at least a substantial portion of said 180 degrees of a circle, said moving surface driving the material into a roll, each set of rollers having each roller parallel and in line with a corresponding roller in the other set, said sets being laterally disposed to each other but separated apart and having an open, unobstructed area therebetween; introduction means for introducing the material into said rolling section; removal means for removing the rolled material from said rolling section, said removal means including an extended member extended in a direction at least generally perpendicular to the axis of the curved surface defined by said rolling section, the rolled material being removed from said rolling section by the extended member moving through and across said open area, moving the rolled material out of said rolling section; and folding means for folding the rolled material as desired after it is removed from said rolling section by said removal means.