US2766951A - Tension compensating apparatus - Google Patents

Description

Oct. 16, 1956 H. A. GEORGE 2,766,951

TENSION COMPENSATING APPARATUS Filed Aug. 18, 1953 "Winn INVENTOR Homo/70 4. GEORGE United States Patent Oflice 2,766,951 Patented Oct. 18, 1956 TENSION COMPENSATING APPARATUS Howard A. George, Oyster Bay, N. Y.

Application August 18, 1953, Serial No. 374,886 2 Claims- (Cl. 242-150 Therefore, as the reel or spool is unwound, the force,

required to turn the reel decreases rapidly proportiom ally to the weight of the wire on thereel.

In many applications, for instance in the automatic winding of coils or in the general handling of the wire, it is desirable and necessary to maintain a fairly constant control of the tension of the wire as it is unwound. The techniques of adjusting the tension of light wires or thread, for instance by means of a pivotally mounted tension arm are not applicable to the case of heavy wires, since the tension arm would have to be very heavy and cumbersome,

Other tensions have been built in which the drag on spool could be adjusted to any desired degree. They give questionable satisfaction because with a full spool the tension is at a minimum and with an empty spool it has increased to a maximum since the force arm meas ured from the surface of the spool of wire to its center decreases constantly as the spool is emptied. The present invention overcomes this difliculty since as the spool is emptied, the amount of drag in terms of torque required to turn the spool decreases accordingly.

The present invention generally comprises mounting bracket means for pivotally mounting a reel supporting shaft on the bracket, means for adjusting the angular elevation of the shaft, and a brake disc mounted in fixed relation to said shaft so that the brake disc and the reel mounted on the shaft form a friction clutch, the amount of friction being determined by the weight of the loaded reel and the angle of elevation of the shaft, the coefiicient of friction being a constant.

In the present invention as a full reel is unwound, the drag decreases due to the weight of the spool decreasing, and increases due to the shortening of the force arm radius. These two etfects may be made to compensate in linear fashion by adjusting the elevation angle, and thereby the frictional drag.

Another advantage is that the present invention is self loading since the shaft may be cranked below horizontal and then elevated after a reel is partially slid on. Thus even the heaviest reels may be easily loaded.

Through the discussion, we have used wires as our illustrative example, however, rope or any other material which is adapted to be wound around a reel may be utilized with the invention without extending the scope thereof, and the term wires in the specification and claims is used as a generic term to cover all such material.

Accordingly, it is a principal object of the invention new and improved tension compensating means for unreeling wires comprising a reel, a shaft adapted to rotatably support said reel, a brake disc mounted coaxislly on said shaft, a component the weight of said reel thereby hearing on said brake disc, and means to adjust the angle of said shaft with respect to the horizontal, whereby the amount of friction between said reel and said brake disc will vary proportionately to a function the angle of said shaft with respect -to the horizontal.

Another object of the present invention is to provide new and improved tension adjusting means comprising a reel, a brake disc adapted to bear on said reel and means to adjust the friction between said brake disc and said reel, to thereby balance the loss of weight against the changing of force arm radius.

Another object of the present invention is to provide new and improved tension compensating means comprising a reel, a brake disc adapted to bear on said reel and means to adjust the friction between said brake disc and said reel, said adjusting means comprising means to adjust the vertical component of the weight of said reel bearing on said brake disc.

Another object of the present invention is to provide tension adjusting means for wire or rope reels, comprising a supporting platform, a shaft mounted on said platform and means to adjust the angle of said shaft with respect to the horizontal, a brake disc mounted coaxially on said shaft and a reel mounted coaxially on said shaft and adapted to bear on said brake disc.

Another object of the present invention is to provide an adjustable mounting for a reel of wire which is adapted to provide simple and easy handling of said wire including means for adjusting the tension of said wire, and simple and easy means to load the reels.

Another object of the present invention is to provide means for automatically maintaining substantially con.- stant tension as a reel is unwound from full to empty.

These and other objects of the invention will be apparent in the following specification and figures of which:

Figure 1 is a side view of an embodiment of the invention.

Figure 2 is a top sectional view of the embodiment of Figure l.

Figure 3 is a view of spring loading means,

Referring to Figures 1 and 2, there is shown a triangular mounting bracket having a bottom member 1 and side members v2 and 3. The embodiment of the invention shown provides two separate tensioning devices, one one each side. Therefore, the discussion of one tensioning device will apply equally to the other.

A rod 4 is connected to the mounting bracket 33' by means of the clamps 5 and 6. The triangularly shaped structural member 7 is pivotally connected to the rod 4, and rod 4 extending through a bearing 10 in the member 7. The angular position of the member 7 with respect to the horizontal, is adjusted by the threaded rod member 11, which is connected to the member 7 by means of the connecting plate 12. The connecting plate 12 is pivotally mounted to the member 7 by means of bolts 13 and 13', and the connecting plate 12 has a tapped hole at its center which is adapted to receive the threaded rodmember 11. The threaded rod member 11 is pivotally and rotatably conneetedto the bottom bracket member 1 by means of a ball and socket joint 14. Therefore, as the threaded 3 rod member 11 is rotated, it will change the angular position of the member 7 about the rod 4.

The member 7 has fixed to it a brake member 15, shown as a disc, by means of the bolts 16, 17. A reel supporting shaft 20 is bolted to the member 7 and extends through the brake disc 15. The shaft 20 and the brake disc are shown to have a coaxial relationship.

The reel 21 to be wound or unwound is placed on the shaft 20. A portion of the weight of the reelwill bear on the brake disc 15, as shown by the vectors A and W where W represents the weight. The brake disc 15 and the reel 21 therefore form a fi iction brake type device and the turning of the reel-will be retarded by the amount of the friction between the reel 21 and the brake disc 15. The amount of friction'is proportional to the angular position of the member 7 and shaft 20. When the shaft is horizontal, there will be practically no friction, but when the shaft 20 is tilted as shown, at an angle B, there will be a certain amount of friction developed between the brake disc 15 and the reel '21. The friction will be equal to the vector A times the coemcient of friction for..the particular materials used. Therefore, the braking maybe varied from zero to an amount determined by the maximum angle that the shaft 20 may be elevated. It has been found that sufiicient friction is generated by the design shown in Figure I, when the shaft 20 is elevated to its maximum angle. Greater angles of elevation may be obtained by connecting the threaded rod member 11 further away from the center of the mounting bracket 1, if desired, or the friction might be increased by using materials for the brake disc 15 and the reel 21 which have a greater coefficient of friction. Alternatively a wafer of brake lining material may be placed between the reel and the fixed disc, thereby permitting the reel and disc to be of metal.

Therefore, the present invention provides means for rotatably mounting a reel for unwinding. The mounting means may be adjusted to vary the tension on the wire being unwound.

In operation, when a full reel is placed on the shaft 20, a certain amount of pull will be required to turn the reel depending upon the angle of elevation of the shaft 20. If too much force is required, the rod 11 may be adjusted to lower the elevation angle thereby lowering the friction between the brake disc 15 and the reel 21, or if a greater force is required the rod 11 may be turned to increase the elevation angel B of the shaft 20. As the reel is gradually unwound, it will become lighter, and easier to pull, at which time the angle of elevation may be increased by means of the threaded member 11, if desired.

In this way, substantially constant tension may be kept on the wire or rope being unwound by making simple adjustments of the member 11. A handle 19 may be mounted on the member 11 for ease of adjustment, if desired.

The tension will be maintained automatically if where W =Weight of reel fully loaded W=Weight of reel empty Ry=Full radius force arm R=Empty radius force arm then the loss of drag due to loss of weight will linearly compensate the gain in drag due to decreasing force arm. *The weight of the empty reel may be chosen to fulfill this condition or a compensating weight 25 may be added.

4 The compensating weight 25 may be determined by the following relation:

Wr=Weight of reel Ww=Weight of wire W=Weight of compensating weight Ry=Full radius force arm R=Empty radius force arm Alternatively the reel may be spring loaded as shown in Figure 3. However, the spring method is accurate for only one elevation angle. is loaded by spring assembly 29. The spring may be fixed at the shaft end by nut 30. A bronze bearing may be inserted between the spring and reel to prevent the spring from turning.

Instead of the compensating weight 25 a drag cable brake may be used as shown in Figure 2. This com prises a cable 31 fixed to disc 15 by post 32 and wrapped around the reel 21 in the groove 33. The cable brake quired to be handled, the mounting bracket 1 may be cut in half along its center line. For instance, the right hand half of the mounting bracket is all that is required to handle one reel provided conventional mechanical.

bracing is supplied to support the desired weight.

Another arrangement might be to mount single red devices at right angles to the double reel device shown.

That is, there will be four reels, eachseparated by Various other modifications and arrangements will occur to those desiring to utilize the principals of the invention in view of the specific number of wires required for a particular application. The mounting brackets may be made rectangular for vertical stacking, and may be mounted on vertical surfaces if desired.

The reels may be easily loaded without lifting them off the ground by cranking the shaft 20 below horizontal and partially sliding the reels on and thenalternately elevating the shaft and sliding the reel on.

Addin'onal clamps 5' may be added for different size reels and the mounting brackets 2 and 3 may be suitably perforated to accurate clamps for different size reels.

I claim:

1. Spool handling equipment comprisinga pair of mounting brackets, a horizontal member supported .by said mounting brackets, a shaft member rotatably supported by said horizontalmember, control means connected to said shaft member to adjust the angular position of said shaft relative to said horizontal member, a friction brake face plate fixedly mounted to said shaft member, and a cable brake mounted on said friction brake face plate, said cable brake adapted to cooperate with an end plate of a spool mounted on said shaft member.

2. Spool handling equipment comprising a pair of mounting brackets, a horizontal member supported by said mounting brackets, a shaft member rotatably supported by said horizontal member, control means connected to said shaft member to adjust the angular position of said shaft relative to said horizontal member,

a friction brake face plated fixedly mounted to said shaft in Figure 3 the reel 21' member, a cable brake mounted on said friction brake face plate, said cable brake adapted to cooperate with an end plate of a spool mounted on said shaft member, and spring means attached to the terminal of said shaft member and adapted to urge a spool mounted on said 5 shaft member toward said friction brake face plate.

References Cited in the file of this patent UNITED STATES PATENTS 207,612 Locke Sept. 3, 1878 220,465 Chase et al. Oct. 14, 1879 1,514,767 Hill Nov. 11, 1924

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