US2058549A - Clamp - Google Patents

Description

Oci. 27, 1.936.

A. o AUSTIN CLAMP Filed July 27', 1933 .im c @n MUM .N om mm n du S www ATTORNEY Patented Oct. 27, 1936 UNITED STATES messie PATENT OFFICE` CLABIP Jersey Application July 27, 1933, Serial No. 682,447

6 Claims.

This invention relates to clamps for conductors and is particularly adapted to conductors having hollow cores or conductors of other formation which are not readily gripped by snubbing about a seat.

desired per unit length.

Another object of the invention is to `provide a clamp which will automatically adjust itself to any reduction in the diameter of the conductor` due to the tension thereon so as to insure maintenance of its grip upon the conductor.

A further object of the invention is to provide a clamp having a resilient grip to insure a continuous gripping action and to compensate for .diierential expansion and contraction of the parts.

Other objects and advantages will appear from the following description.

The invention is exemplified by the combination and arrangement of parts shown in the accompanying drawing and described in the following specication, and it is more particularly pointed out in the appended claims.

In the drawing:

Fig. 1 is a fragmentary elevation of a portion of a clamp embodying the present invention and showing the anchor end thereof.

Fig..2 is a side elevation on a larger scale than Fig. 1 showing the gripping portion of the clamp.

Fig. 3 is a section on line 3-3 of Fig. 2.

Fig. 4 is a section on line 4-4 of Fig. 3.

In high voltage transmission lines, it is highly desirable that the clamp used for gripping the conductor shall be such that it may be readily placed upon a taut conductor. It is also desirable that the clamp shall be so constructed that it will not damage or mar the conductor so that the clamp can be relocated if desired.

Heavy tensions or loads on the conductor tend to decrease its diameter. For this reason it is difficult to grip conductors even though the clamp seats be very long. The conductor is at maximum tension where it enters the clamp. Since a heavy load tends to reduce the diameter of the conductor, this reduction in diameter may remove the pressure and friction at the point of entry.

`This tends to throw the grip further back in the clamp where the pressure is again released due to the reduced diameter. In this way, even clamps of very long seats and starting with high initial pressures frequently will not hold a conductor under working conditions.

With my improved type of clamp, the deficiencies commonly present in many types are removed and a clamp is provided which will grip practically any type of conductor when made of the proper size and provided with su'icient length 5 of gripping seat. y

In the improved type of clamp, provision is made for applying and maintaining pressure even though the diameter of the conductor may be reduced appreciably under increased working load. l0 The construction is such that a wedging. action takes place, compensating for any decrease in diameter. In Figure 1 the incoming conductor I0 enters a seat formed by liners II, provided with inclined surfaces I2, The tension on the conduc- 15 tor is taken up by the liners I I through the longitudinal component of the force between the rolling members I3 and the liners. The rolling members operate between inclined surfaces I2 on the liner and inclined surfaces I5 on outer take-up plates I6. The longitudinal component or tension is transferred from the outer take-up plates I5 to the arm Il. The arm I'I may be an integral part of the plates I6 or may be attached by the bolts I8. The member I'I is provided with an eye 2- I9 for attaching to an insulator yoke or suitable adapter.

The method of applying the clamp is as follows. The outer plates I5 and liners II are fastened together by suitable connectors which will hold the two parts with their interposed rolling members in position. One way of holding these parts in proper position is by means of retainers 20 shown in section in Fig. 4. These members 20 are attached in any suitable way to the plates I6 and have flanges 2l that t loosely in grooves in the edges of the liners I I. They not only hold the parts I I and I6 in assembled relation but also prevent the rolling members I3 from becoming displaced, and at the same 0 time permit a relative longitudinal and transverse movement between the members Il and I6 to adjust for the load or for contraction in the cable. The gripping portion consists essen tially of the two halves I I with the various parts held together as described. These are placed over the conductor and bolts 22 are tightened so that there will be some initial pressure between the liner pieces I I and the conductor I0. Since the liner pieces have straight grooves, they 50 may be placed on the taut conductor. The extension Il made in two parts may be attached to the clamp plates I6 after the plates are clamped to the cable. The spacing between the two halves of the extension can be such that the conductor will not bind between the parts I1. The insulator or yoke for holding the cable to its support may then be attached to the eye I 9 by means of any suitable connection.

As tension is taken up, the slack will be thrown into the end of the conductor. The slack portion of the conductor may then be bent into the proper position to form a jumper as at deadend points. If the clamp has been placed at the proper point on the conductor, sufficient slack will be thrown into the jumper section 23 so that .this jumper section may be steadied by means of a liner 24 clamped between a support member 25 which is a part of the extension member I'I.

In some cases, the arm used for steadying the jumper may be dispensed with while in others a very long arm may be necessary to prevent undue swinging of the jumper. ber 25 may be removable or may be provided with different locations for the liner member 24 s0 that the angle between the jumper 23 and the axisof the clamp may be changed to meet various conditions.

The construction of the clamp is such that an` appreciable irregularity in the surface is provided for. This is very desirable from the manufacturing standpoint as well as from the construction standpoint. The member I6, while having considerable strength longitudinally, may be readily bent by the bolts so that if adjacent rolling members or inclined surfaces have slightly different clearances, it is possible to bring the parts in contact. This is further aided by the resiliency in the rolling members I3, which may be tubes having continuous resilient walls.

In order that the resilient tube members will Y not be seriously distorted by applying too heavy a load through the gripping bolts, internal spacing members or rolls 26 may be placed in a portion, if not all, of the resilient members I3. In this case, further deformation of the tubular members is arrested when the Walls of the tubular members come into contact with the backing-up rolls 26. The tubular members preferably are made of resilient material such as phosphor or silica bronze, or galvanized or stainless steel. The pressure may be graded by use of the tubular members having different degrees of stiffness or by leaving out the backing-up members 26 from some of the rollers. Normally the grip with this type of construction is automatically graded when the tension in the conductor is taken up by the clamp. The reduction in tension as the conductor passes through the seat of the clamp tends to lessen the amount of contraction of the conductor, thereby insuring a heavy grip or pressure between the conductor and the clamp at the rear of the gripping seat. If a heavy tension is applied to the conductor, this will tend to reduce the diameter. As this reduction will be greatest at the point of entry, it is seen that a graded grip will be produced.

It will, of course, be understood that the clamp may take a number of different forms and still come within the scope of the invention. Some of the advantages of the clamp are its ability to grip a taut conductor and provide practically any degree of pressure desired per unit length, and its ability automatically to adjust itself to any reduction in the diameter of the conductor so as to insure maintenance of grip. Resiliency is provided in the gripping members, which feature helps to insure grip on the conductor at all times and to provide for differential ex- The steady memj `Ainterposed between said wedging faces, said rollers being sufficiently compressible and expansible to hold substantially the entire contact surfaces of said seat members in gripping engagement with the conductor notwithstanding unequal contraction of said conductor under tension.

2. A clamp for electrical conductors or the like comprising seat members shaped to conform to opposite faces of a taut conductor, pressure members cooperating with the outer faces of said seat members respectively, said pressure members and seat members having cooperating wedging faces distributed longitudinally of said conductor, resilient rollers interposed between said wedging faces, and threaded means for exerting initial pressure on said pressure members to cause said seat members to grip said cable, said rollers being sufficiently compressible and expansible to hold substantially the entire contact surfaces of said seat members in gripping engagement with the conductor notwithstanding unequal contraction of said conductor under tension.

3. A clamp for electrical conductors or the like comprising seat members for engaging opposite sides of the conductor, the engaging faces of said seat members extending in straight lines parallel to the axis of the conductor to permit said seat members to engage a taut conductor, pressure members for holding said seat members in contact with said conductor, said seat members and pressure members having cooperating wedging faces distributed longitudinally of said conductor for causing a pull on said conductor to increase the pressure of said seat members on the surface of said conductor, resilient rollers interposed between said wedging faces, and adjustable means for clamping said pressure members together to exert initial pressure on said seat members, said rollers being sufficiently compressible and expansible to hold substantially the entire contact surfaces of said seat members in gripping engagement with the conductor notwithstanding unequal contraction of said conductor under tens1on.

4. A clamp for conductors comprising a pair of seat members foi` engaging opposite sides of a conductor, grippers for pressing said seat members against said conductor, said grippers and seat members having cooperating inclined bearing faces distributed longitudinally thereof, resilient rollers interposed between said bearing faces, a plurality of bolts distributed longitudinally of said clamp for drawing said grippers toward each other and for pressing the bearing faces on said grippers against said resilient rollers, said grippers being sufficiently flexible to permit control of the distribution of the stress along said cable by the tension in the individual bolts.

5. A cable clamp jaw comprising a seat member, a gripper for exerting pressure on said seat member, said seat member and gripper having cooperating inclined bearing faces, rollers interposed between said bearing faces, means for pressing said gripper against said rollers and keepers for retaining said rollers in position, said keepers providing for relative longitudinal and transverse movement of said gripper and seat member.

6. Means for gripping a cable comprising seat members and pressure members having cooperating Wedging faces acting to force said seat members against said cable under tension on said cable, and a plurality of hollow resilient rollers interposed between said pressure members and seat members and distributed in spaced relation to one another along said seat members and adapted individually to exert yielding pressure on said seat members, said rollers being suiciently compressible and expansible to maintain said seat members in contact with said cable notwithstanding unequal contraction of said cable under tension.

ARTHUR O. AUSTIN.

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