US3286005A - Method of making polyolefin bags - Google Patents

Description

Nov. 15, 1966 c. A. copK METHOD OF MAKING POLYOLEFIN BAGS 2 Sheets-Sheet 1.

Filed April 19, 1965 CHARLES ACOOK INVENTOR.

Nov. 15, 1966 c, 00K 3,286,005

METHOD OF MAKING POLYOLEFIN BAGS Filed April 19, 1963 2 Sheets-Sheet 2 I PRINTER CHARLES A,COOK

INVENTDR EXTRUDER United States Patent 3,286,005 METHOD OF MAKING POLYOLEFIN BAGS Charles A. Cook, Tyler, Tex., assignor to National Distillers and Chemical Corporation, New York, N.Y., a corporation of Virginia Filed Apr. 19, 1963, Ser. No. 274,120 Claims. (Cl. 264-95) This invention relates to a novel method of manufacture of polyolefin type bags and more specifically relates to a method of manufacturing such bags wherein, after printing on a tube of polyolefin material, the tube is reinflated and rotated with respect to a pair of subsequently collapsing nip rolls. By this method a new crease line is formed along a printed area of the bag while the original crease line falls along the front and rear panels of the bag.

Polyolefin bags and the manufacture thereof are well known to the art. Generally, a tube of polyolefin material is drawn from appropriate extrusion die and the tube is thereafter collapsed and the surfaces may be printed upon. The tube is then transmitted to a bag making machine which in essence cuts the tube into a plurality of lengths, one end of which is sealed and the other of which is open, so that individual bags are formed. In the past such difficulty has been experienced in the opening of the bags and in providing printing for the bags which will be observable along the edge of the bag when the bag is filled.

In accordance with the invention and after the printing step has been completed the tube is reinflated and is caused to be rotated with respect to a pair of collapsing nip rolls. Thereafter a new crease or bag edge is formed which can lie directly over printing intended to be in the edge of the bag while the original creases fall in the front and rear panels of the bag. Accordingly, when the bag is filled, the side printing will be continuous and be easily observable while at the same time the crease lines in the front and rear panels form lair channels extending into the bag which permit the easy opening thereof, as is described in the copending application Serial No. 274,119 filed April 19, 1963, now US. Pat. No. 3,216,646 titled, Side Printed Easy Opening Polyolefin Bag.

Accordingly, a primary object of this invention is to provide a novel method of manufacture of a polyolefin type bag which can be easily opened.

A further object of this invention is to provide a novel method of manufacture for polyolefin bags which permits the direct printing on the front or rear panels or both which ultimately becomes the edge of the bag.

These and other objects will become apparent from the following description when taken in connection with the drawings, in which:

FIGURE 1 illustrates a bag printed in accordance with the concepts of the present invention.

FIGURE 2 schematically illustrates the unsealed end of the bag of FIGURE 1 when the bag is unfilled, to particularly illustrate the formation of creases in the front and rear panels of the bag.

FIGURE 3 is a partially diagrammatic and partially perspective view of the manner in which the preprinted tube of film is rotated and reinfi-ated and then reclosed prior to the bag forming process.

FIGURE 4 is a side plan view of the twister mechanism of FIGURE 3.

FIGURE 5 is an enlarged detail view which illustrates the manner in which the slats of FIGURE 4 may be secured to their side support members.

Referring first to FIGURE 1, there is illustrated therein a novel bag construction wherein a bag is comprised of a front panel 10, a rear panel 11, an edge portion 12, which connects the front and rear panels 10 and 11, and sealed ends 13 and 14. The end 13 is a previously sealed end and the bag prior to being filled as shown in FIGURE 2 was open at front end 14. The front end 14 of the bag is schematically illustrated in FIGURE 2 with the bag collapsed prior to the filling openation. It will be noted that the bag of FIGURE 2 has two manufacturers creases 15 and 1 6 (crease 16 is seen in FIGURE 1) and additionally has further creases 17 and 18 in panels 10 and 11 respectively. The creases 17 and 18 provide means for easily opening the bag of FIGURES 1 land 2. That is to say, a typical polyolefin bag of the prior art is difficult to snap open since the inner surfaces of the front and rear panels tend to stick together. In accordance with the invention, however, additional creases 17 and 18 run completely along the length of the bag to provide air passages within the bag [and a thumb hold for ease of opening.

As a further feature of this invention, it can be seen in FIGURE 1 that printed information (the label 6N 14 appears directly in the side of the bag and straddles crease line 16. Therefore, when bags of the type of FIGURE 1 are placed in a large stack, this identifying information is readily observable as contrasted to prior art type bags which contain information either on front or rear panels which were hidden from view.

The manner by which the bag of FIGURES 1 and 2 can be manufactured is illustrated in FIGURES 3, 4 and 5. FIGURE 3, is a schematic illustration of the method of manufacture leading to the printing of an extruded tube which ultimately is formed into bags. Thus, in FIGURE 3 there is illustrated an extruder 20 which may be of any desired type well known to those skilled in the art, which eXtrudes a thin walled tube 21 of any appropriate polyolefin material.

The tube 21 is grasped at its upper end by appropriate nip roll means 22 which is also well known to those skilled in the art, which flattens the tube to an appropriate flat web which is ultimately processed in any desired manner and then is applied to a printer 23. The printer 23, which may be of any desired type, then pn'nts some repetitive pattern on the tube moving in the direction of the arrow 24, where the pattern on the upper side of the web is shown by shading lines while a similar pattern is printed on the rear panel of the web as shown by dotted lines. i

All of the foregoing are steps well known to those skilled in the art, and in the past, the printed web coming down printer 23 is connected to a bag making machine which now cuts the tube into predetermined lengths, one end of which is sealed and the other end of which is open to form a bag. web 21 is transmitted to a pair of nip rolls 22 and 23 and through a twisting structure 24 which will be described more fully hereinafter.

Essentially, the purpose of twisting structure 24 is to cause the web 21 to rotate. The web 21 emerging from the end of twister 24 is then inflated between the end of twister 24 and a second pair of nip rolls 25 and 26 which recolla-pse the lower tube 21a. It is to be specifically noted, however, that since tube 21a is rotated that when the nip rolls 25 and 26 recollapse tube 21a, the original crease line 30 and 31 of web 21 will now lie in the front and rear panels 32 and 33 respectively and new crease lines 34 and 35 are formed for the tube.

In accordance with the invention, however, the

In comparing the flattened tube of FIGURE 3 to the bag of FIGURE 5 is it now seen that crease line 30 corresponds to crease 17 of FIGURE 2 while the other crease line 31 corresponds to crease line 18 of FIGURE 2 to provide the desired air passages and thumb holds needed for easy opening of the bag. Moreover, it will be seen that the printed pattern, such as patterns 40 and 41, which were originally on the front and rear panels of the tube prior to the passage through twister 24, are now directly over the crease lines 35 and 34 respectively. Therefore, bags formed from the flattened tube leaving nip rolls 25 and 26 will, when filled have the printed material of areas 40 and 41 on the side of the bags. By way of example, area 41 could be printed with the information 6N-24 shown in the edge 12 of FIGURE 1, where this printing is done with conventional printing techniques in the front and rear panels of the bag by the printer 23, although it ultimately appears on the edges of the bag after the twisting operation.

It is to be specifically noted that in a typical manufacturing process it is desirable that the nip rolls 22, 23, 25 and 26 be parallel to one another. Therefore, a twisting operation is necessary to rotate tube 21a to the position shown in FIGURE 3. Clearly, however, no twisting operation is necessary if nip rolls 25 and 26 form some angle to the axis of nip rolls 22 and 23. That is to say, in accordance with the invention, it is only necessary that the web be reinflated and then recollapsed at a new angle with respect to the axis of the bag.

Where the twisting operation is found desirable, the twister 24 can be provided as illustrated in FIGURES 3, 4 and 5 by means of a plurality of spaced slats such as a first group of slats 50 which are supported by end supports 51 and 52 and a second similar group of slats such as slats 53 which are supported by end supports 54 and 55. It will be noted particularly from FIGURE 5 that supports 51 and 55 are parallel to one another and are at an angle to the supports 52 and 54. Moreover, supports 52 and 54 are parallel to one another and are spaced from one another by end clamps 60 and 61 to maintain a predetermined spacing between the faces of slats 50 and 53. In a similar manner, members 51 and 55 are held spaced from one another by end clamps 62 and 63 whereby the other end of slats 59 through 53 are held spaced from one another.

Accordingly, a web twisting area is designed between the opposing surfaces of slats 50 and 53 to twist the web 21 which rides between the spaced slats in the manner illustrated in FIGURE 3. Slats 50 and 53 as well as their supports 51 through 55 can be formed of any desirable material and can be secured to one another in any desired manner.

By way of example, FIGURE 6 illustrates the manner in which support 52 is secured to one end of slat 50, Thus the slat 50 has a countersunk opening 70 therein which receives the head of a bolt 71. Bolt 71 extends through an opening in slat 50 and a cooperating opening in member 52 and is captured on the other side of member 52 by means of an appropriate washer 72 and nut 73 which is threaded onto the end of bolt 71. By appropriately loosening these connections it will be clear that the twisting structure 24 can be rotated to any desired twisting angle with external support structure (not shown) thereafter maintaining the structure in this twisted position with the individual securing means between the supports and the slat being thereafter tightened.

In the foregoing, the invention has been described only in connection with the preferred embodiments thereof. Many variations and modifications of the principles of the invention within the scope of the description herein are obvious. Accordingly, it is preferred to be bound not by the specific disclosure herein, but only by the appending claims.

What is claimed is:

1. The method of manufacturing a polyolefin bag which includes the steps of drawing a tube of polyolefin material, flattening said tube on a first and second crease line, reinflating said tube, and reflattening said tube on crease lines removed from said first and second crease lines.

2. The method of manufacturing a polyolefin bag which includes the steps of drawing a tube of polyolefin material, flattening said tube on a first and second crease line, reinfiating said tube, and reflattening said tube on two crease lines removed from said first and second crease lines; and thereafter cutting said tube into predetermined lengths to form bags having crease lines in the top and bottom surface thereof to permit ease of opening of said bag.

3. The method of manufacturing a polyolefin bag which includes the steps of drawing a tube of polyolefin material, flattening said tube on a first and second crease line, rotating said flattened tube, reinflating said tube, and reflattening said tube on two crease lines removed from said first and second crease lines.

4. The method of manufacturing a polyolefin bag which includes the steps of drawing and flattening a tube of polyolefin material, passing said flattened tube through a first nip roll means, rotating said flattened tube about the axis thereof through an angle less than reinfiating said tube and thereafter passing said reinflated tube through second nip roll means having axes parallel to said first nip roll means to reflatten said tube.

5. The method of manufacturing a polyolefin bag which includes the steps of drawing and flattening a tube of polyolefin material on a first and second crease line, passing said flattened tube through a first nip roll means, rotating said flattened tube about the axis thereof through a predetermined angle, reinflating said tube and thereafter passing said reinflated tube through second nip roll means having axes parallel to said first nip roll means to reflatten said tube on a third and fourth crease line removed from said first and second crease lines.

6. The method of manufacturing a polyolefin bag which includes the steps of drawing and flattening a tube of polyolefin material on a first and second crease line, passing said flattened tube through a first nip roll means, rotating said flattened tube about the axis thereof through a predetermined angle, reinflating said tube and thereafter passing said reinflated tube through second nip roll means having axes parallel to said first nip roll means to reflatten said tube on a third and fourth crease line removed from said first and second crease line; and thereafter cutting said tube into predetermined lengths to form bags having crease lines in the top and bottom surface thereof to permit ease of opening of said bag.

7. The method of manufacturing a polyolefin bag which includes the steps of drawing a tube of polyolefin material, flattening said tube on a first and second crease line, printing on at least said top surface of said flattened tube, reinflating said tube, and reflattening said tube on two crease lines removed from said first and second crease lines.

8. The method of manufacturing a polyolefin bag which includes the steps of drawing a tube of polyolefin material, flattening said tube on a first and second crease line, printing on at least said top surface of said flattened tube, reinflating said tube, and reflattening said tube on two crease lines removed from said first and second crease lines, with at least one of said two crease lines extending through the printing on said top surface of said flattened tube.

9. The method of manufacturing a polyolefin bag which includes the steps of drawing a tube of polyolefin material, flattening said tube on a first and second crease line, printing on at least said top surface of said flattened tube, rotating said flattened tube, reinflating said tube, and reflattening said tube on two crease lines removed from said first and second crease lines.

10. The method of manufacturing a polyolefin bag which includes the steps of drawing and flattening a tube of polyolefin material on a first and second crease line, printing on at least said top surface of said flattened tube, passing said flattened tube through a first nip roll means, rotating said flattened tube about the axis thereof through a predetermined angle, reinfiating said tube and thereafter passing asid reinflated tube through second nip roll means having axes parallel to said first nip roll means to reflatten said tube on a third and fourth crease line removed from said first and second crease lines; at least one of said first and second crease lines extending through said printing on said top surface of said flattened tube.

References Cited by the Examiner UNITED STATES PATENTS 2,838,799 6/1958 Meister 26494 2,980,963 4/1961 Makowski 264-132 3,110,554 11/1963 Yazumi 264132 3,155,752 11/1964 Reigler 26495 ROBERT F. WHITE, Primary Examiner.

ALFRED L. LEAVITT, Examiner.

R. B. MOFFITT, Assistant Examiner.

Claims (1)

1. THE METHOD OF MANUFACTURING A POLYOLEFIN BAG WHICH INCLUDES THE STEPS OF DRAWING A TUBE OF POLYOLEFIN MATERIAL, FLATTENING SAID TUBE ON A FIRST AND SECOND CREASE LINE, REINFLATING SAID TUBE, AND REFLATTENING SAID TUBE ON CREASE LINES REMOVED FROM SAID FIRST AND SECOND CREASE LINES.

Images