US2534130A

US2534130A - Wire tensioning device

Info

Publication number: US2534130A
Application number: US136053A
Authority: US
Inventors: William R Hunt
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1949-12-30
Filing date: 1949-12-30
Publication date: 1950-12-12
Anticipated expiration: 1967-12-12
Also published as: FR1030232A

Description

1950 w. R. HUNTY 2,534,130

' WIRE mnsronmc ngvrcs Filed Dec. 50, 1949 Inventor: William R. Hunt- His Attorney.

Patented Dec. 12, 1950 WIRE TENSIONING DEVICE William R. Hunt, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application December :0, 1949, Serial a... 130,053

This invention relates to wire tensioning devices of the type used to maintain constant tension on a wire during coil winding operations.-

In the design of machines for high speed winding of coils, for example transformer coils, it is desirable to maintain constant tension on the wire during the winding operation. In such machines rapid changes in the speed of the wire are encountered and the inertia of the supply spool and the wire causes forces to be exerted on the wire which may cause undue stretching and breaking unless a constant predetermined wire tension is maintained. Furthermore, high inertia forces in tension devices formerly utilized tend to vary the tension on the wire to the extent that the wire is stretched and cold worked to an excessive degree. Copper wire has an elastic limit and when bent beyond this limit, it becomes harder and stiffer. Wire which has been hardened and stiffened by bending or cold working will not lie as flat as the wire which has not been coldworked and consequently the layers of cold worked wire in a coil take up more space than in a coil formed of very soft and ductile wire. In addition, wire passing through ordinary wire tensioning devices may become stretched reducing the diameter. The elastic limit is exceeded when the wire is bent more than a certain angle. Whenever wire passes over a pulley or idler wheel, as on a tensioning device, it is bent twice, once when it goes on the wheel and once when it comes on the wheel. It is the radius of the wheel which is important and not the angle of contact between the wheel and the wire since once the wire has been bent to conform to the contact of the wheel, it bends no more until it again leaves the wheel. Thus, if the direction of a traveling wire is changed through 180 by passing it over two pulleys which each bend at 90", it is cold worked twice as much as if it were bent through 180 by being passed over a single pulley. It is therefore desirable in the design of a wire tensioning device to keep to a minimum the number of direction-changing pulleys over which the wire passes and that such pulleys be of relatively large diameter in order to avoid cold working of the wire.

An object of this invention is to provide an improved wire tensioning device.

Another object of this invention is to provide an improved wire tensioning device wherein the wire is not cold worked.

A further object of this invention is to provide an improved wire tensioning device in which the wire is passed around only a single wheel.

Claims. (Cl. 242-455) Furtherobjects and advantages of this invention will become apparent and the invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which, characterize this invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In accordance with this invention, there is provided a light weight low inertia spokeless ring of relatively large diameter around which the wire is passed. Three idler rollers engage the inner surface of the ring to provide rotatable support therefor, two of the rollers being mounted on a stationary member. The third roller is mounted on one end of a lever arm which is in turn pivotally mounted on the stationary member. A spring acts on the lever arm to urge the third roller against the ring to provide rolling friction thereon and to tend to deform the ring from a circle to a triangle. An idler pulley is mounted on the other end of the lever arm and bears on the wire leaving the ring. Increased tension on the wire leaving the ring acts on the idler pulley to cause the lever arm to move against the spring so that the third roller applies less pressure on the ring. This reduces the rolling friction on the ring and also allows the ring to tend to return to its circular shape permitting it to rotate more freely. Conversely, decreased wire tension allows the spring to urge the third roller against the ring applying more pressure so as to increase the rolling friction and to increase the deformation of the ring.

In the drawing Fig. 1 is a side elevation view of the improved wire tensioning device of this invention and Fig. 2 is a cross section view taken along the line 2-4 of Fig. 1.

Referring now to Fig. 1, there is shown a light weight deformable spokeless ring i of relatively large diameter having a groove 2 formed in its outer periphery. A pair of fixed idler rollers 3 are mounted on a spider 4 in a suitable manner, as for example by studs 5. The rollers 3 are pref erably mounted on antifriction bearings as at 6. The spider I is in turn secured to a stationary frame member I in any suitable manner, as by studs 8. A third antifriction bearinged idler roller 9 is provided mounted on a movable lever arm III by a stud II and the lever arm I! is in turn pivotally mounted on the spider member 4, as at 12. The fixed rollers 3 and movable roller 9 engage the inner surface of the ring I, which may be rubber faced, as at l3, to provide a rotatable support for the ring I. An antifriction bearing mounted idler pulley I4 is mounted on the other end of the pivoted lever arm III by a stud I5. A spring I 6 is held in compression between the lever arm I and an extension portion ll of the spider member 4 and serves to bias the lever arm III to urge the movable roller 9 against the ring I to provide rolling friction on the ring. In addition, the pressure applied by the movable roller 9 by virtue of the spring I6 tends to deform the ring I from a circle toward a triangle. A set screw I8 in the end of the extension H of the spider member 4 is provided to adjust the pressure applied on the ring I by the movable roller 9.

The wire I9 from a supply spool (not shown) is wrapped around the ring I one and one quarter times and the wire leaving the ring I passes under the pulley ll. The wire 20 is deflected slightly from a straight line by the pulley I4 due to the loading of the tensioning spring I6. As the tension on the wire 20 leaving the ring I is increased, the wire 20 tends to straighten,

causing the pulley I4 to move the lever I 0 against the spring I6 reducing the pressure on the ring I applied by the roller 9. This allows the ring I to tend to return to its circular shape and the reduction in rolling friction also permits the ring I to turn more freely. Conversely, a decrease in the tension of the wire 20 leaving the ring I permits the spring I6 to move the lever arm III to increase the pressure applied on the ring I by the roller 9. This not only increases the rolling friction, but, as pointed out above, tends to deform the ring I from its original circular shape further increasing the friction effect used for tensioning the wire. A pressure type tensioner ZI applies a slight initial tension to the wire I9 entering the ring I so as to hold the wire on the ring I.

It, can be readily seen that the inertia in this device is reduced to a minimum since the pulley or ring I around which the wire passes does not have spokes or a hub. Furthermore, the wire is passed around only a single pulley and, therefore, cold working of the wire is avoided. In this connection, it has been found that for ordianry sizes of wire the radius of the ring I should be at least 4 inches to insure that the wire 20 leaving the ring is ductile.

It will now be readily apparent that this invention provides an extremely simple device for maintaining constant tension on a wire and furthermore, since this device utilizes a single low inertia relatively large diameter ring, around which the wire is passed, cold working of the wire is prevented thus facilitating coil winding. While three idler rollers are shown, it will be readily understood that a different number may be used, for instance four with two fixed rollers and two movable rollers.

While I have illustrated and described a particular embodiment of this invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that this invention is not to be limited to the particular arrangement disclosed, and I intend in the appended claims to cover all modification which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A wire tensioning device comprising a spokeless ring adapted to have said wire passed therearound, a plurality of idler rollers engaging the inner surface of said ring for rotatably supporting said ring, at least one of said rollers being mounted on one end of a movable lever arm, resilient means for urging said one roller against said ring providing rolling friction thereon, and an idler pulley mounted on the other end of said lever arm and adapted to bear on the wire leaving said ring whereby increased tension on said wire causes said one roller to apply less pressure on said ring permitting said ring to turn more freely.

2. A wire tensioning device comprising a spokeless ring adapted to have said wire assed therearound, a plurality of idler rollers engaging the inner surface of said ring for rotatably supporting said ring, at least one of said rollers being movably mounted, resilient means -for urging said one roller against said ring providing rolling friction thereon, and means responsive to the tension of the wire leaving said ring for increasing or decreasing the pressure applied by said one roller.

3. A wire tensioning device comprising a relatively large diameter spokeless ring adapted to have said wire passed therearound, a plurality of idler rollers engaging the inner surface of said ring for rotatably supporting said ring, at least one of said rollers being mounted on one end of a pivotally mounted lever arm, spring means acting on said lever arm to urge said one roller against said ring providing rolling friction thereon, and an idler pulley mounted on the other end of said lever arm adapted to bear on the wire leaving said ring whereby increased tension on said wire causes said lever arm to move against said spring causing said one roller to apply less pressure on said ring permitting said ring to turn more freely.

4. A wire tensioning device comprising a relatively large diameter spokeless ring adapted to have said wire passed therearound, a plurality of idler rollers engaging the inner surface of said ring for rotatably supporting said ring, at least one of said rollers being mounted on one end of a lever arm pivotally mounted on a stationary member, the remaining rollers being mounted on said stationary member, spring means acting on said lever arm to urge said one roller against said ring for providing rolling friction thereon, and an idler pulley mounted on the other end of said lever arm adapted to bear on the wire leaving said ring whereby increased tension on said wire causes said lever arm to move against said spring so that said one roller applies less pressure on said ring permitting said ring to turn more freely.

5. A wire tensioning device comprising a relatively large diameter spokeless ring adapted to have said wire passed therearound, three idler rollers engaging the inner surface of said ring at equally spaced intervals for rotatably supporting said ring, two of said rollers being mounted on a stationary member, the third of said rollers being mounted on one end of a lever arm pivotally mounted on said stationary member, spring means acting on said lever arm to urge said third roller against said ring providing rolling friction thereon, and an idler pulley mounted on the other end of said lever arm adapted to bear on the wire leaving said ring whereby increased tension on said wire causes said lever arm to move against said spring so that said third roller applies less pressure on said ring permitting said ring to turn more freely.

6. A wire tensioning device comprising a spokeless low inertia deformable ring adapted to have said wire passed therearound, a plurality of idler rollers engaging the inner surface of said ring for rotatably supporting said ring, at least one of said rollers being movably mounted, resilient means for urging said one roller against said ring providing rolling friction thereon and tending to deform said ring from a true circle, and means responsive to the tension on the wire leaving said ring for increasing or decreasing the pressure applied by said one roller.

7. A wire tensioning device comprising a spokeless low inertia deformable ring adapted to have said wire passed therearound, a plurality of idler rollers engaging the inner surface of said ring for rotatably supporting said ring, at least one of said rollers being mounted on one end of a pivotally mounted lever arm, resilient means for urging said one roller against said ring providing rolling friction thereon and tending to deform said ring from a true circle, and an idler pulley mounted on the other end of said lever arm adapted to bear on the wire leaving said ring whereby increased tension on said wire causes said one roller to apply less pressure on said ring permitting said ring to turn more freely and allowing said ring to tend to return to a circular shape.

8. A wire tensioning device comprising a relatively large diameter, spokeless, low inertia deformable ring adapted to have said wire passed therearound, a plurality of idler rollers engaging the inner surface of said ring for rotatably supporting said ring, at least one of said rollers being mounted on a pivotally mounted lever arm, spring means acting on said lever arm to urge said one roller against said ring providing rolling friction thereon and tending to deform said ring from a true circle, and an idler pulley mounted on the other end of said lever arm adapted to bear on the wire leaving said ring whereby increased tension on said wire causes said lever arm to move against said spring so that said one roller applies less pressure on said ring permitting said ring to turn more freely and allowing said ring to tend to return to a circular shape.

9. A wire tensioning device comprising a relatively large diameter, spokeless, low inertia deformable ring adapted to have said wire passed therearound, a plurality of idler rollers engaging the inner surface of said ring for rotatably supporting said ring, at least one of said rollers being mounted on one end of a lever arm pivotally mounted on a stationary member, the other of said rollers being mounted on said stationary member, spring means acting on said lever arm to urge said one roller against said ring providing rolling friction thereon and tending to deform said ring from a true circle, and an idler pulley mounted on the other end of said lever arm adapted to bear on the wire leaving said ring whereby increased tension on said wire causes said lever arm to move against said spring so that said one roller applies less pressure on said ring permitting said ring to turn more freely and allowing said ring to tend to return to a c'ircular shape.

10. A wire tensioning device comprising a relatively large diameter, spokeless, low inertia deformable ring adapted to have said wire passed therearound, three idler rollers engaging the inner surface of said ring at equally spaced intervals for rotatably supporting said ring, two of said rollers being mounted on a stationary member, the third of said rollers being mounted on one end of a lever arm pivotally mounted on said stationary member, spring means acting on said lever arm to urge said third roller against said ring providing rolling friction thereon and tending to deform said ring from a circle to a triangle, and an idler pulley mounted on the other end of said lever arm adapted to bear on the wire leaving said ring whereby increased tension on said wire causes said lever 'arm to move against said spring so that said one roller applies less pressure on said ring permitting said ring to turn more freely and allowing said ring to tend to return to a circular shape.

WILLIAM R. HUNT.

No references cited.