US3912188A

US3912188A - Damped flexure mounts for use in web winding

Info

Publication number: US3912188A
Application number: US500496A
Authority: US
Inventors: Raymond Marvin Ballard
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1974-08-26
Filing date: 1974-08-26
Publication date: 1975-10-14
Anticipated expiration: 1992-10-14
Also published as: CA1044206A; LU73248A1; AR205403A1

Abstract

In a machine for continuously winding a web onto a wind-up roll having at least a lay-on roll in contact with the surface of the wind-up roll and a spreader roll ahead of the lay-on roll, the improvement wherein the lay-on roll and the spreader roll are mounted within a frame by damped flexure mounts supporting the ends of the rolls and attached by resilient attachments. The flexural mounts have a plurality of alternating spring steel leaves and leaves of polymeric material.

Description

United States Patent [1 1 [111 3,912,188 Ballard Oct. 14, 1975 [54] DAMPED FLEXURE MOUNTS FOR USE IN 1,419,049 6/1922 Harsel 242/752 WEB WINDING 2,267,107 12/1941 .luillard 242/753 3,048,346 8/1962 Karber 242/753 [75] Inventor: .Raymond Marvin Ballard, 3,670,980 6/1972 Mukal 242/752 X Midlothian, Va.

[73] Assignee: E. I. Du Pont de Nemours and Primary ExaminerEdward J. McCarthy Company, Wilmington, Del.

[22] Filed: Aug. 26, 1974 [57] ABSTRACT PP .1 500,496 In a machine for continuously winding a web onto a wind-up roll having at least a lay-on roll in contact [52] US. Cl. 242/75.2 with the surface of the wihd'up reh and a Spreader [51] Int. Cl B65h 23/10 ahead of the lay'eh roll the improvement wherein the [58] Field of Search n 242/752 75.3. 267/36 R lay-on roll and the spreader roll are mounted within a 267730 41 5 4 frame by damped flexure mounts supporting the ends of the rolls and attached by resilient attachments. The [56] References Cited flexural mounts have a plurality of alternating spring UNITED STATES PATENTS 9/1917 Trier 242/752 steel leaves and leaves of polymeric material.

11 Claims, 3 Drawing Figures U.S. Patent Oct. 14, 1975 Sheet 1 of2 3,912,188

US. Patent Oct.14,1975 sheetzofz 3,912,188

DAMPED FLEXURE MOUNTS FOR USE IN WEB WINDING BACKGROUND OF THE INVENTION This invention relates to a mounting device, and more particularly to a flexible mounting device having improved damping properties.

In certain manufacturing processes, e.g., the production of films, where the end product or any intermediate thereof is a web of material there is a need for improving the method by which handling and winding of the webs onto rolls is accomplished. A typical web winding apparatus comprises a plurality of rolls arranged to guide the web onto -a winding roll. Where thin flexible webs are continuously wound at high speeds the winding system becomes very critical and sensitive to variations in web tension and other disturbances caused by rolls having eccentric cores.

Of particular concern where webs are produced on rolls in their finished form is the elimination of transverse direction wrinkles and machine direction ridges which may result in permanent distortion of the web material. The transverse direction wrinkles are convolutions in the transverse direction which occur in the interior of a wound roll and are caused by low mean tension levels and high tension peaks in the web during winding and by an excessive amount of air that is wound-in 38 during windup.

Machine direction ridges are circumferential ridges occurring throughout a roll and are caused, in particular, by high web tension levels and a lack of lateral web mobility during winding. No web tension level is known to exist where neither problem occurs.

The prior art has recognized some of the problems involved in winding webs of material. US. Pat. No. 3,329,368 to Mastriani, for example, discloses an improvement in a web winding machine for automatically adjusting the position of the axis of a rewind roll relative to the position of a lay-on roll, responsive to variations in diameter of the rewind roll. The lay-on roll is disposed in intermediate engagement with a platen and rewind roll by means of a spring plate and connecting link. This arrangement appears to improve web handling where there exists no unsupported web by allowing the lay-on roll to adjust to changes in diameter of the rewind roll while exerting constant pressure.

DESCRIPTION OF THE INVENTION It has been found that transverse direction wrinkles and machine direction ridges can be substantially eliminated in accordance with the present invention which is particularly pointed out in the appended claims and is illustrated in a preferred embodiment in the accompanying drawings wherein:

FIG. 1 is a perspective view ofa web winding apparatus incorporating flexure mounting devices of the present invention.

FIG. 2 is a right end view of the apparatus of FIG. 1 taken along line 22.

FIG. 3 is an enlarged, detailed elevational view of a flexure mounting device in accordance with the present invention.

Referring now to FIGS. 1 and 2, a web of material such as polymeric film is wound onto a winding roll 11. A pivot roll 12, a spreader roll 13 and a lay-on roll 14 are arranged in essentially parallel relation to winding roll 11 by means ofa frame 15 comprising support arms l6 and 17 which are attached to a pivot shaft I8 at

points

19 and 20, respectively. Air cylinders 21 are used to lift the frame assembly 15 and provide friction damping for the pivoted support arms 16 and 17.

During the winding process lay-on roll 14 remains in contact with the surface of winding roll 11 at 22. Uniform constant pressure contact at 22 must exist between the lay-on roll 14 and the winding roll 11 to maintain a constant minimum thickness air layer that is wound-in. Surface irregularities in winding roll 11 may produce a bouncing contact between lay-on roll 14 and winding roll 11. Friction damping is provided to overcome said bouncing contact by means of damped flexure mounts 23 in accordance with the present invention. Friction damping provides a smoother more effective control than viscous damping for low velocities and small displacements involved in bouncing contact.

A spreader roll 13 (such as a Flex-Spreader" roll manufactured by the Samuel Bingham Company) is located immediately ahead of the lay-on roll 14. It is attached to support arms 16 and 17 by means of clamped flexure mounts 24 aligned parallel to the web 10 approaching the roll to preclude web tracking problems. The spreader roll 13 tenters (i.e., provides transverse direction tension to the incoming web 10 by the action of helical-conical grooves provided in the soft rubber roll surface. Machine direction tension produces transverse direction tensile stress in the web 10 by the outward resilient movement of the conical elements of the roll. When a web 10 is wound on a winding roll having an eccentric core, a sinusoidal tension variation is induced. In a preferred embodiment of the present invention damped flexure mounts 23 and 24 (enlarged, detailed views of which are shown in FIG. 3) provide for relative motion between lay-on roll 14 and spreader roll 13 thereby creating a desired accumulator effect to attenuate web tension variations.

Counterweights 25 are employed to establish the desired force, i.e., nip pressure, between lay-on roll 14 and winding roll 11. In a preferred embodiment damped flexure mounts 26 are used to mount said counterweights 25 to an extension of support arms 16 and 17 thereby to reduce the dynamic inertia, i.e., impedance, of the pivoted support frame 15. Optionally, the counterweights 25 can be attached to pivot shaft 18 by means of a damped flexure mount 26 and cantilever beam member 27.

Referring now to FIG. 3 (which illustrates in an enlarged, detailed view the

flexure mounts

23 and 24 and how they are associated with

rolls

14 and 13, respectively) the damped flexure mount 50 of the present invention consists essentially of a plurality of alternating spring steel leaves 51 and leaves of polymeric material 52 rigidly fastened at one end by any suitable means 53. In a preferred embodiment the fastening means is adapted to be rigidly mounted on the support arms 16 and 17 of frame 15. The opposite end of the flexure mount 54 is adapted to fasten to the ends 55 of a web handling roll 58 by means of resilient attachments 56. In a preferred embodiment said resilient attachments 56 comprise a plurality of resilient washers such as Belleville spring washers arranged alternately and assembled with any suitable machine fastener 57.

The alternating spring steel leaves 51 can be formed of any suitable grade steel with AISI 1070 or AISI 4130 heat treated steel being preferred.

In a preferred embodiment the polymeric leaves 52 consist essentially of a polyacetal resin having a static coefficient of friction in the range of about 0.15 to 0.3. The dynamic coefficient of friction ranges between about 0.18 and 0.33. Asbestos-phenolic compositions can also be used for the polymeric leaves 52.

When the flexure mount of the present invention is ready for use, the load imposed on the resilient washers 56 by the fastener 57, which can be a typical machine bolt, is adjusted to achieve the critical damping required of the web carrying roll 58. In a particularly preferred embodiment of this invention in the use of damped flexure mountswith web handling machines, the polymeric leaf material is selected to have a lower static coefficient of friction than dynamic coefficient of friction (e.g., a difference of about 0.02 to 0.05) thereby precluding a slip-stick phenomenon.

The damped flexure mount of the instant invention provides an improved and simple method of attenuating tension variations in web handling machines. Disturbances in the winding process that would normally cause web elongations and consequent induced tension variations are absorbed by changes in length of the web span between the lay-on roll 14 and spreader roll 15 because of their capability to move relative to one another. The multiple uses of damped flexure mounts for roll and counterweight mounting provides a low inertia, high compliance system.

I claim:

1. In a machine for continuously winding a web onto a wind-up roll comprising a lay-on roll in contact with the surface of the wind-up roll, the improvement wherein said lay-on roll is mounted within a frame by damped flexure mounts supporting the ends of said layon roll one end of said flexure mounts being attached to said frame and the other end being attached to the ends of said roll by resilient attachments, said flexure mounts having a plurality of alternating spring steel leaves and leaves of polymeric material.

2. A machine as defined in claim 1 wherein said frame has a spreader roll mounted thereon by damped flexure mounts supporting the ends of said spreader roll one end of said flexure mounts being attached to said frame and the other end being attached to the ends of said roll by'resilient attachments, said spreader roll positioned to permit said web to pass thereover prior to passing around said lay-on roll.

3. A machine as defined in claim 2 wherein said spreader roll and said lay-on roll move relative to one another by means of damped flexture mounts thereby creating an accumulator effect to attenuate web tension variations when winding a web of material, portions thereof being unsupported.

4. A machine as defined in claim 2 wherein said frame comprises at least two support arms each having a counterweight suspended therefrom by means of a damped flexure mount one end of said flexure mount being attached to said arm and the other end being attached to said counterweight by resilient attachments thereby to establish the desired nip pressure between said lay-on roll and said wind-up roll.

5. A machine as defined in claim 4 wherein said resilient attachments comprise a plurality of resilient washers. I

6. A machine as defined in claim 4 wherein said polymeric material has a static coefficient of friction within the range of about 0.15 to 0.3 and a dynamic coefficent of friction with the range of about 0.18 to 0.33, said static coefficient being lower than said dynamic coefficient.

7. A machine as defined in claim 6 wherein the polymeric material is a polyacetal resin or an asbestos containing phenolic resin.

8. A damped flexure mounting device for mounting web handling rolls on a frame comprising a plurality of alternating spring steel leaves and leaves of polymeric material, and resilient attaching means for attaching one end of said flexure mounting device to the ends of such rolls i 9. A flexure mounting device as described in claim 8 wherein said resilientattaching means comprise a plurality of resilient washers. 7

10. A flexure mounting device as defined in claim 9 wherein said polymeric material has a static coefficient of friction within the range of about 0.15 to 0.3 and a dynamic coefficient of v friction within the range of about 0.18 to 0.33, said static coefficient being lower than said dynamic coefficient.

11. A flexure mounting device as defined in claim 10 wherein the polymeric material is a polyacetal resin or an asbestos containing phenolic resin.

Claims

1. In a machine for continuously winding a web onto a wind-up roll comprising a lay-on roll in contact with the surface of the wind-up roll, the improvement wherein said lay-on roll is mounted within a frame by damped flexure mounts supporting the ends of said lay-on roll , one end of said flexure mounts being attached to said frame and the other end being attached to the ends of said roll by resilient attachments, said flexure mounts having a plurality of alternating spring steel leaves and leaves of polymeric material.

2. A machine as defined in claim 1 wherein said frame has a spreader roll mounted thereon by damped flexure mounts supporting the ends of said spreader roll , one end of said flexure mounts being attached to said frame and the other end being attached to the ends of said roll by resilient attachments, said spreader roll positioned to permit said web to pass thereover prior to passing around said lay-on roll.

4. A machine as defined in claim 2 wherein said frame comprises at least two support arms each having a counterweight suspended therefrom by means of a damped flexure mount , one end of said flexure mount being attached to said arm and the other end being attached to said counterweight by resilient attachments thereby to establish the desired nip pressure between said lay-on roll and said wind-up roll.

5. A machine as defined in claim 4 wherein said resilient attachments comprise a plurality of resilient washers.

8. A damped flexure mounting device for mounting web handling rolls on a frame comprising a plurality of alternating spring steel leaves and leaves of polymeric material, and resilient attaching means for attaching one end of said flexure mounting device to the ends of such rolls .

9. A flexure mounting device as described in claim 8 wherein said resilient attaching means comprise a plurality of resilient washers.

10. A flexure mounting device as defined in claim 9 wherein said polymeric material has a static coefficient of friction within the range of about 0.15 to 0.3 and a dynamic coeFficient of friction within the range of about 0.18 to 0.33, said static coefficient being lower than said dynamic coefficient.