US2419372A

US2419372A - Tension control arrangement for winding systems

Info

Publication number: US2419372A
Application number: US583188A
Authority: US
Inventors: Everett J Schneider
Original assignee: Sylvania Electric Products Inc
Current assignee: GTE Sylvania Inc
Priority date: 1945-03-17
Filing date: 1945-03-17
Publication date: 1947-04-22
Anticipated expiration: 1964-04-22

Description

April 22, 1947. E. J. SCHNEIDE R 2 I TENSION CONTROL ARRANGEMENT FOR WINDING SYSTEMS Filed March 17, 1945 2 SheetsSheet 1 INVENTOR. ang

' ATTOPNIE'Y W 1947- E. J. SCHNEIDER TENSIONCON'I ROL ARRANGEMENT FOR WINDING SYSTEMS Filed March 17, 1945 2 Sheets-Sheet 2 A TTUFA/fy Patented Apr. 22, 1947 UNITED STATES PATENT OFFICE TENSION CONTROL ARRANGEMENT FOR WINDING SYSTEMS Application March 17, 1945, Serial No. 583,188

l Claim. 1

This invention refers to reeling and unreeling of filamentary material and more particularly to methods and apparatus for establishing a desired tension in the material being unreeled from one spool and wound up on another spool.

The invention is of particular benefit in applications where a filamentary material is passed from one spool through a number of processing positions to another power driven-spool, as in pickling or electroplating wire, or coating it with an insulating or thermionically emitting material, and in drying, lacquering or similar processing, either in a continuous or in interrupted motion. The invention is, however, useful in all operations where it is desired to transfer filamentary material from one spoolto one or several other spools.

In operations of this kind it is usually necessary that a well-defined tension be maintained during the transfer of the filamentary material, e. g., wire, so as to avoid slackening of any por tion of its free length between the spools or between auxiliary intermediate guiding pulleys. Uniformity of tensions and of the rotation of the spools for insuring uniform motion of the filament or Wire in its full free length becomes very important for the reeling of material having very low tensile strength.

In one kind of reeling system the spindle carrying the spool, onto which the filament or wire is being transferred, is power driven, preferably at constant speed, and the required tension is obtained by applying a frictional force to the spinspool and reeling it up dle from which the filamentary material is being unreeled. The invention is concerned with this type of reeling and unreeling system and deals with means for controlling the frictional force opposing the rotation of the supplying spindle.

According to a conventional method the required friction is applied to the spindle carrying the spool from which the filamentary material is unreeled by a solid brake shoe or a solid flexible brake band, whose pressure on the spindle, or on a. separate brake drum rigidly attached to the spindle can be adjusted in any convenient way, e. g., by adjusting the tension of a spring attached to the frictional or brakin member.

While this method of supplying friction to the supplying spindle is satisfactory for many purposes, I have found that it has serious limitations when it is desired to unreel filamentary material of low tensile strength, and when the reeling motion has to be interrupted and restarted at regular intervals, as is the case in unwinding very small diameter wire from a large supply again in smaller spools carrying shorter standard lengths, and particu, larly if the wire is to be processed on its way from the supply spool to the power driven takeup spool. The tension of such wire must not only remain constant during the runnin operation, but it is, in addition, desirable that the frictional force be large enough to stop the rotation of the supplying spool within a fraction of a full turn whenever the rotation of the power driven take-up spool is interrupted. If this condition is not fulfilled, i. e., if the supply spool continues paying out wire which is not being taken up by the take-up spool, undesirable lengths of wire accumulate in some places between the spools. These tension-free parts of the wire may become entangled and interfere with the smooth restarting of the reeling motion.

The friction on the supply spindle must, therefore, be adjusted to be large enough to act as a fast working brake. If the wire being transferred has very low tensile'strength, it is, of course, necessary that this friction be kept below the tensile strength of the wire.

The frictional force between the surfaces of solid bodies (as between a brake drum and a brake shoe or band), is, however, usually larger under static conditions than during the motion, when the two surfaces are sliding with respect to each other. A larger force is thus necessary to start the motion from rest, than to overcome the friction at uniform speed, and, as a result, an excess tension occurs in the wire every time the reeling-motion is started. This initial excess tension is due, substantially, to the difference between the static and the sliding friction between solid surfaces. An additional excess tension at the time of starting the unreeling motion results from the necessity of overcoming the iner tia of the system comprising the supply spool and spindle.

It is thus obvious, that the friction at the supply spindle must be carefully adjusted, so as to produce the proper fast braking action when the reeling motion is interrupted, and at the same time so as to insure that the initial tension at the instant of starting the reeling motion remains below the tensile strength of the material being unreeled, in order to prevent tearing or stretching of material. For wire of very low tensile strength, the frictional force must therefore be controlled between narrow limits, and I have found that great difiiculties are experienced in making the necessary adjustments when the conventional method of friction between solid surfaces is used in the unreeling of wire or other filamentary material of very low tensile strength.

It is, therefore, a principal object of the invention to provide frictional means for an unreeling system in which the initial excess tension of the material being unreeled is reduced to a minimum.

It is another object of the invention to provide means for controlling the tension of the material during all phases of an unreeling operation between precise and narrow limits.

It is a still further object of theinvention to provide a frictional tensioning device for the supply spindle of an unreeling system, in which the resistance of a plurality of radial vanes rotating in a viscous liquid provides the required tension.

According to another object of the invention, the tension in a thread or wire being unreeled is adjusted by varying the distance between a rotatable and a stationary wheel provided with radial arms.

A feature of the invention refers to the variation of frictional forces applied to a spindle to be intermittently rotated, by varying the depth of immersion of a rotatable vaned wheel below the surface of a viscous fluid.

Another feature of the invention provides means for controlling the friction of a rotatable spindle by varying the level of a viscous fluid with respect to a rotating paddle which is rotatable within the fluid.

It is a further object of the invention to provide a fluid frictional device for an unreeling system, in which the tension of the unreeling material may be changed by replacing a fluid of one viscosity by a fluid of another viscosity.

According to the invention, the conventional friction between solid surfaces applied to the spindle carrying th spool from which the filamentary material is being unreeled, is replaced by a viscous fluid coupling system. The resistance required for obtaining the desired tension is obtained from the motion of a paddle wheel adapted to rotate with the spindle in a pool of viscous fluid, and the principal features of the invention can be described in connection with the fluid coupling members which are attached to the supply spindle.

The rotation of the supply spindle in the unreeling operation is due to the torque supplied by thefllamentary material bein pulled away by a second, power-driven, take-up spool of the unreeling system. The viscositypf the fluid surrounding the paddle wheel provides a torque in the opposite direction which is proportional to the angular velocity of the paddle wheel (or a power thereof), and to the viscosity of the surrounding alike, with two exceptions.

Fig. 5 is a cross-sectional view of Fig. 3, along the line 5-5 thereof.

Fig. 6 is a schematic diagram of a reeling system embodying the invention.

The fluid coupling system consists of stationary part and of rotatable parts. As shown in Fig. l, the stationary parts comprise a bearing box 24, cylindrically flanged annular disk l3 and tank l1. Tank l'i serves as a container for the viscous fluid (not shown in the drawing), which couples the paddle wheel l9 to paddle wheel 30 and tothe inner surface 38 of tank 11.

Rotatably mounted in and passing through bearing box 24 is spindle 9 which has suitable ball bearings 1 and II. At the-upper of spindle 9 is shown chuck 5, provided with springs I arranged to hold in place a supply spoo1 40 (Fig. 6) from which the filamentary material 4| is being unreeled. The lower end 3| of spindle 9 carries the hub 42 of paddle wheel l9, which is adapted to rotate with spindle 9.

As shown more clearly in Figs. 3 and 4, the outer diameter of rim 43 0f paddle wheel I9 is smaller than the inner diameter of the cylindrical wall of tank I1, forming an annular space 36 between rim 43 of the paddle wheel and the cylindrical wall of tank 11. As the tank is filled with fluid, the annular space 36 is fully or partly occupied by the tank fluid, to provide a viscous coupling between rim 43 and inner wall section 38 of the tank. The radial spacing between rim 43 and the inner wall of tank I] is preferably less than 5% of the radius of the Wheel. At the bottom 26 of tank ll, inside of the tank, is provided a stationary paddle Wheel 30 (Fig. 5), rigidly attached to bottom 26 by screws 44. Paddle wheel 30, as more clearly shown in'Fig. 2 consists of a plurality of radial vanes 29, centrally attached to hub 21 and terminating peripherally in rim 28, and attached at their lower edges to bottom 23 which is provided with holes 35 in at least some of the sectors between the vanes. The holes serve for the passage of screws 44 adapted to firmly attach Wheel 30 to the bottom 26 of tank l1. Wheel 30 represents the stator of the fluid coupling system, in which the paddle wheel I9 is adapted to rotate. The outer diameter of paddle wheel 30 is very nearly qual to the inner diameter of the cylindrical wall of tank H, as shown in Fig, 5.

Wheels I9 and 30 are thus built very nearly The outer diameter of rim 43 of wheel I9, is slightly smaller than that of rim 28 of wheel 30. The two paddle wheels are mounted coaxially with respect to from each other by an adjustable distance 31.

fluid. The characteristics of a fluid coupling of this type depend, in addition, on the distance of the rotating paddle wheel from certain stationary members forming part of the fluid coupling, and on the shape of the paddle wheel and of the coordinated stationary members.

The invention will now be described in corn nection with the drawing, in which,

Fig. 1 is an isometric View of the parts compris-' ing the fluid coupling system according to the invention.

Fig. 2 is an isometric view of one of the paddle wheels forming part of the fluid coupling system.

Fig. 3 is a, longitudinal or axial section of part of the fluid coupling system shownjn Fig. 1*.

Fig. 4 is a cross-sectional view of Fig. 3, along the line 4-4 thereof.

Preferably, wheel I9. is attached to the spindle with its flat disk-like portion 45 facing upward. This arrangement adapts the vanes 46 of wheel I9 for exerting a positive torque on the fluid in the tank. This torque is coupled through the viscous liquid onto the vanes of stationary wheel 30. The frictional characteristics. of the fluid coupling system may thus be adjusted by adjusting the axial spacing 31 between the lower edges of vanes 46 and the upper edges of vanes 29.

In order to adjust the axial distance between the coaxially located rotor and stator, disk l3, which is coaxially joined to bearing box 24, is provided with 'a threaded cylindrical flang 25, onto which the upper threaded rim 34 of cup 11 can be screwed. A knurled locking ring I5 is provided at theupper end of rim 34, which when in a change in axial spacing between stator 30.

and rotor 19. The thread on flange 25 is so chosen that the axial distance between the coupling wheels can be controlled within narrow limits.

As cup I! is filled with a, viscous fluid, the

frictional characteristics of the fluid coupling can be controlled by the viscosityof the fluid being used, and by the axial distance between the fluid coupling wheels.

Due to the intrinsic slip of a fluid coupling system of this particular type at low velocities, there is no danger of an initial excess tension imparted to the filamentary material when the rotation of the unreeling system is started. n the other hand, the viscous friction can be so adjusted'that spindle 9 stops rotating within a fraction of a full turn when the rotation of the power-driven take-up spindle is interrupted.

The frictional control between rotor and stator by viscous coupling may, however, be carried out in difierent ways. According to one method, the liquid level in cup I I is kept high enough so as to insure complete immersion of stator and rotor in the fluid for all adjustments of their mutual axial distance. It is, however, possible to control the frictional characteristic of the fluid coupling by keeping the level of the viscous fluid low enough, whereby a change of height of cup [1 with respect to the rotor will not only result in a variation of the axial distance between stator and rotor, but will simultaneously change the depth of immersion of the rotor blades into the fluid.

If desired, holes 41 may be provided in disk 45 which forms the "ceiling" of rotor l 9, to facilitate the passing of air through the rotor. This prevents the formation of air bubbles in the inverted rotor cup, when it is inserted and insures proper depth oi? immersion of all parts of the rotor when the liquid level is chosen lower than the upper end of the rotor.

The friction between solid surfaces is reduced to a minimum by the use of ball bearings, as shown in Fig. 1. If desired, rollerbearings may be used in place of the ballbearings.

The invention is particularly useful in the reeling and unreeling of extremely fine metal filaments such as those having a diameter of the order of .00035 inch and in particular where the filament must undergo certain processes between the payofl! reel and the winding reel. For example, as shown in Fig. 6, the device of Figs. 1 to 5 is illustrated diagrammatically and carries payofl' reel 40 having the fine wire metal filament 4] provide it with a thin coating of a suitable material and then the coated filament passes through a heating coil or chamber 5|, and then through another processing device 52 from. whence it passes to the reel 53. Because of the fineness of the filament wire, it has been found that a winding control device such as that described in connection with Figs. 1 to 5, is necessary in order to reduce the likelihood of breakage of the filament during the winding operation.

What is claimed is:

A' fluid coupling system comprising, a paddle wheel supported by a spindle, a stationary paddl wheel mounted coaxially with and in axially adjustable spaced relation with respect to the first paddle wheel, a pool of viscous liquid in which both paddle wheels are submerged, a tank containing the fiuid and surrounding the two paddle wheels, the first paddle wheel comprising a plurality of radial vanes extending between the central hub portion and a peripheral rim portion and a disc-shaped portion extending between the hub and the rim along the edges of the vanes at the side of the wheel remote from the stationary paddle wheel, the stationary paddle wheel comprising a plurality of radial vanes extending between a central hub portion and a peripheral rim portion and the disc-shaped portion extending between the edges of the hub and the rim along the edges of the radial vanes pointing away from the first paddle wheel, said stationary paddle wheel being rigidly attached to a wall of said tank, means for supporting said spindle, means for supporting said tank, means for adjusting the axial spacing between the paddle wheels; the said means for supporting said spindle including a bearing box; the said means for supporting said tank comprising an annular disc provided with a threaded cylindrical peripheral flange and with a. central portion rigidly attached to said bearingbox; and the said-means for adjusting the said axial spacing between the paddle wheels includes a threaded portion on the wall of the tank which is adapted to fit into the cylindrical peripheral flange ofsaid annular disc supporting the tank.

. EVERETT J. SCHNEIDER.

REFERENCES CITED The following references are oirecord in the file of this patent:

which may pass through a coating bath 50 to UNITED STATES PATENTS British Apr. 7, 193?