US3467333A

US3467333A - Web slitter

Info

Publication number: US3467333A
Application number: US669818A
Authority: US
Inventors: Nathan W Wilson
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1967-09-22
Filing date: 1967-09-22
Publication date: 1969-09-16
Anticipated expiration: 1986-09-16
Also published as: LU56938A1

Description

P 1969 N. w. WILSON 3,467,333

WEB SLITTER Filed Sept. 22, 1967 INVENTOR NATHAN W. WILSON ATTORNEY United States Patent 3,467,333 WEB SLITTER Nathan W. Wilson, Circleville, Ohio, assignor to E. I. du Pont deNemours and Company, Wilmington, Del., a corporation of Delaware Filed Sept. 22, 1967, Ser. No. 669,818 Int. Cl. B65h 35/02, 17/08 US. Cl. 242-56.2 3 Claims ABSTRACT OF THE DISCLOSURE Web slitting apparatus having a pivoted arm to position wind-up cores, and including a gas filled resilient container bearing on the pivoted arm, for high speed operation and efficient start-up.

Related art This invention is an improvement of the web slitting and winding apparatus of the type described in Nicholson, United States Patent No. 2,777,644 issued Jan. 15, 1957.

Background The formation of good rolls when a multiplicity of narrow strips of thin web, such as film, paper or fabric, are wound on individual rolls is dependent on the character of the material and on the nature of the winding arrangement. The slitting and winding of a film on a pivoted arm slitter of the Nicholson invention can be operated at speeds of to 200 to 400 or more feet per minute. At the higher speeds the pivoted arms winding in contact with the pull roll tend to bounce on the roll, leading to poor windup pattern of the slit roll.

There have been attempts to improve the winding performance of the slitter apparatus. In US. 3,122,335 it is proposed to use a fluid charged piston on each wind roll. The piston system is subject to oscillation at critical speeds dependent upon arm and piston construction. Other systems are shown in US. 3,198,453 and in US. 2,872,126.

Summary of invention In the present invention, web slitting machine of the Nicholson type is improved by including therewith a gas filled resilient container cooperating with the positioning pivoted arms. In a specific embodiment the invention comprises a web slitting machine having a web supply, means for slitting continuous web into a plurality of strips, a positively driven web driving roll over which the strips pass, and cores in peripheral rotating contact with the web driving rolls and upon which the strips are wound, and pivoted arms positioning the cores in substantially parallel relationship in peripheral contact with the driving roll and a gas filled resilient container cooperating with the pivoted arm and urging the cores in contact with the web driving roll.

The gas filled device of the invention achieves an improvement in roll formation by minimizing arm bounce by damping the oscillations which occur, resulting in slit rolls with a smooth windup pattern and Without unwanted beading. Furthermore and of considerable importance, the device can be readily deflated and re-inflated to permit rapid set-ups.

The invention will be more clearly understood by reference to the accompanying drawing wherein:

FIGURE 1 is a simplified schematic drawing of a slitting apparatus employing a device of the present invention; and

FIGURE 2 is a view of a gas filled hold-down device of the present invention as it bears on a pivot arm of the apparatus.

Patented Sept. 16, 1969 ice Referring to FIGURE 1, a continuous web 11, e.g., a thermoplastic film such as polyethylene terephthalate, is unwound from a supply roll 12 and thereafter is slit by knife 13, positioned between supporting

rolls

14 and 15, and then passes over the surface of main web driving drum or roll 16. At web driving roll 16 the web, having been ,slit into a plurality of narrow strips, is wound as shown upon core 17 which is mounted at the free end of the pivot arm 18. Pivot arm 18, suspended to rotate freely about axis 19, has gas-filled hold-down device 20 to urge the windup roll 21 into uniform surface contact'with driving roll 16. A back-up plate 22 is provided to mount and support the hold-down device 20. The next adjacent strip of web is wound upon core 17 mounted at the free end of pivot arm 18, and so on substantially identical to the apparatus already described. That is, eachstrip is individually wound on a separate core disposed on the periphery, alternatively in two or more rows parallel to the axis of driving roll 16.

It 'should be understood that the rolls are driven, directly or through another driven roll, at speeds adapted to maintain the film or web under tension. Hence as rolls of wound material increase in diameter, speed of rotationis adjusted in the usual fashion to maintain the desired surface speed and, therefore, the designed film tension for good roll formation.

FIGURE 1 illustrates a general type of slitting apparatus wherein the present invention is highly useful but it is understood that the present invention can be employed in any type of slitting apparatus wherein the slit ends of the web or film are ultimately conducted onto a roll or rolls of the type illustrated in FIGURE 1.

Still with reference to FIGURE 1, the free end of pivot arm 18 is provided with a short shaft or a mandrel upon which is mounted a rotatable chuck for rigidly mounting thereon core 17. The core 17 can be of cardboard, wood, metal, plastic, etc., and is in rotating contact with the surface of driving roll 16. Core 17 may, if desired, be positively driven in a direction so as to maintain tension of a desired degree upon the roll which forms on this core. It should be understood that the present web winding apparatus is not restricted with respect to the number of individual winding positions which are located in peripheral contact with driving roll 16 of FIGURE 1. Usually, as indicated hereinbefore, additional rolls parallel to roll 21 on core 17 are positioned alternately on an are about driving roll 16 so as to provide proper clearance for free motion of pivot arm 18 and winding of roll 31 on core 17.

FIGURE 2 illustrates in somewhat greater detail the gas filled resilient hold-down device of the present invention and its cooperation with the pivoted arm of the rewinder in contact with driving roll 16. This figure illustrates the device in a preferred embodiment, but modification therefrom can be made to conform to individual requirements.

Shown in FIGURE 2 is rigid support plate 22 to which the device 20 is fixedly clamped, as by suitably shaped flanges on the plate 22 and a rigid top portion 26 on the gas bag or device 20. Plate 22 can be attached to the machine frame (not shown) or other location adapted to cause the device 20 to exert force against pivot arm 18.

The gas filled resilient container 20 can suitably be made of a thin wall reinforced elastomer tube which, of course, is sealed to be gas impervious. For example, the container or bag can be made from a l-ply, fabricreinforced, cured, natural rubber about 60 mils thick. In use, such a bag is inflated to 2 to 10 p.s.i. gauge. A rigid tread top 26 and bottom 24 (FIG. 2) integral to the container 20 make it easy to attach to the support plate 22 and to avoid contact wear of the container 20 as it bears on the pivot arm. An elastomer with a Shore A durometer hardness of 45-50 is suitable for the treads. A tread of A to /2 inch thickness and A to 2 inches wide will function well with a pivot arm. The hold-down device is preferably of a size to extend the full length of the wind roll. Consequently, when the pivot arms must be reset to different widths, the adjustments can be made rapidly and easily as follows: the pressure is released from the device 20 through a gas conduit 23. The arm is moved and set. Then the container is repressured through conduit 23 from a gas source, e.g. a compressor.

The give or yield required of the resilient container 20 will depend upon the location on the arm. A yield of 1 to 3 inches has been found satisfactory for rolls up to 12 inches in diameter and 6 inches wide. The gas or inflatant employed can be any permanent gas such as air, nitrogen, or carbon dioxide.

In operation, the hold-down device 20 presses again the pivot arm 18. As the windup roll 21 increases in diameter after taking up web or film from driving roll 16, the pivot arm 18 compresses the container 20 which thereby maintains pressure on the pivot arm, damping oscillations caused by arm bounce.

When the improved slitting machine of this invention is used, the slitter may be operated at 600 or more feet per minute. The increase of a factor of 2 or more in speed is achieved without loss in yield because of uneven windup edge.

From the foregoing discussion and description, it is evident that the present discovery is an important improvement in web slitting and winding machines. The improvement efiectively overcomes arm bounce with its attendant effects on rolls produced, and has the further advantage of simplicity in allowing speedy adjustments and set-ups of the equipment. While it has been described with certain details, it should be evident that changes can be made without departing from its scope.

What is claimed is:

1. In a web slitting machine having a web supply from which a continuous web is fed, means for slitting the continuous web into a plurality of continuous strips, a positively driven web driving roll over which the strips pass, and cores in peripheral rotating contact with the web driving roll and upon which the strips are wound, and pivoted arms positioning said cores in substantially parallel relationship and in peripheral contact with the web driving roll, the improvement comprising gas filled resilient container including a tread attached to its surface cooperating with the pivoted arm and urging the cores in contact with the web driving roll.

2. A web slitting machine according to claim 1 including means to fill and exhaust gas from said container to facilitate ready start-up of the slitting machine.

3. A web slitting machine according to claim 1 in which the gas container is formed of gas impervious fabric-reinforced rubber.

References Cited UNITED STATES PATENTS 3,222,004 12/1965 Crowe 242-562 X 3,237,877 3/ 1966 Printz et a1. 242-66 WILLIAM S. BURDEN, Primary Examiner U.S. Cl. X.R.