US2787775A - Wire or line clamp - Google Patents

Description

April 2, 1957 c. G. SORFLATEN ET AL 2,737,775

WIRE OR LINE CLAMP Filed Feb. 5, 1954 FIG. I

I3 I i l2 INVENTORS.

- 1 CHESTER e. SORFLATEN GEORGE R. WHITESIDE ATTORNEY WIRE OR LINE CLAMP Chester G. Sorflaten, Chicago, and George R. Whiteside, Wilmington, 111.

Application February 5, 1954, Serial No. 498,381

2 Claims. (Cl. 339265) This invention relates in general to wire or line clamps and more specifically to a new and improved type of multiple purpose clamp particularly suited for either clamping two or more conductors under high pressure to provide an excellent low resistance electrical connection, or to terminate a tensioned overhead line such as a distribution conductor by clamping the end of the conductor to itself after said end has been looped thru a thimble or other suitable insulator provided for such terminating purposes.

The primary object of this invention is to provide a highly eflicient and durable clamp of the type described which is suitable for making excellent low resistance electrical connections between conductors, especially overhead and either of the same size or of difierent sizes as well as for terminating various sizes of distribution conductors. This object is attained by virtue of the high pressure which the clamp is capable of developing and the highly desirable feature due to closely fitting conductor grooves of suitable length to distribute the pressure evenly to the portion of the conductor or conductors subject to the clamp, whether said conductors be of the single or multiple strand variety.

Another object is to provide a clamp that can be applied with simple hand tools such as adjustable end wrenches or open end wrenches and yet develop an extremely high pressure by the arrangement of its parts in a manner most efficient. I

Another object of this invention in keeping with the foregoing is to provide a clamp especially valuable and for most advantageous use with aluminum conductors.

Still another object of this invention is to provide a clamp suitable for a wide range of conductor sizes with out sacrificing the feature of a uniformly close fitting wire groove.

Yet another object is to provide a clamp the application of which may be achieved with ease by furnishing an assembly of parts which need not be disassembled or disassociated for application to the conductors.

An outstanding feature of this invention resides in its adaptability to manufacture of all the parts thereof from a given metal compatible with the composition of the conductor.

These and other objects and advantages will become more readily apparent as the following description proceeds taken in conjunction with the accompanying sheet of drawings illustrating a preferred embodiment of this invention.

In the drawings:

Fig. l is an exploded view of a clamp according to the present invention having only a single intermediate engaging member or bar so as to accommodate only two conductors or the looped end of a single conductor.

Fig. 2 is an elevational view of the clamp of Fig. 1, in assembled open position ready for application.

Fig. 3 is a top plan view of the clamp of either Fig. 2 or 4.

nited States Patent Fig. 4 is an elevational view of a clamp such as shown in the previous figures but modified to the extent of being provided with a plurality of intermediate engaging members and adapted to clamp and connect a plurality of wires of different sizes. The clamp of this figure is shown in closed or operative position.

Referring now more particularly to the drawings and Fig. 1, a basic member 10 comprises an elongate central section having a groove 11 preferably of semi circular cross section extending the length thereof. The groove 11 provides a wire or line bearing surface to closely embrace a conductor. Midway between the ends of the central section of the basic member 10 and integrally attached to either side are bosses 12 and 13. Openings 14 in each of the bosses 12 and 13 provide slidable entrance for bolts 15 and 16, the heads 17 and 18 of which bear against the outside of the bosses 12 and 13 to exert a pressure against the basic member 10 for clamping the several parts together as will be explained hereinafter. Integrally attached to sides of the boss 13 and on opposite sides of the opening 14 therein are two parallel guides or rails 19 extending upwardly and at right angles to the plane of the inside of the basic member 10. These guides 19 serve to insure alignment of and to retain the several parts of the device in proper relationship or attitude one to another as well as to provide for relative sliding movement of the parts toward and away from the basic member 10, as will be described more fully subsequently.

A cap member 20 comprises a central section correspondingly elongate with that of the basic member ill and having a wire bearing groove 21 preferably of semi circular cross section extending the length of the section to receive a conductor. On either side of the central section of the cap member 26 at its midpoint and integrally attached thereto are bosses 22 and 23 which have threaded openings 24 and 25 to threadably receive the bolts 15 and 16 respectively. The boss 23 may be provided with an extension 26 extending downwardly toward the basic member 10 and between the guides 1s. The extension 26 permits the clamp assembly to be opened to a greater extent without disengaging the bolt 18 which in operation is prethreaded partially into the cap member 20, and it forms an extension to the guiding surfaces 27 on each side of the boss 23 which operate between the two guides 19. This arrangement maintains the cap member 20 in alignment while permitting relative move ment slidably toward and away from the basic member 10. Grooves 28 and projections 29 on each side of the boss 23 (see Fig. 3) retain the boss and its extension 26 between the guides 19 while permitting slidable movement of the cap member 20 relative thereto.

Interposed between the basic member 10 and the cap member 20 there is an engaging or spacer bar member 30. Alignment of the bar member 30 with respect to the other members is achieved by means of the guides 19 attached to the basic member 10 and a rectangular opening formed in the bar member 30 by two arms 32 integrally attached thereto and facing projections 31 on the ends of said arms. The rectangular opening thus formed in the bar member 30 achieves alignment by closely embracing the rectangle formed by the two guides 19 and there- 'by prevents rotation and restricts movement toward and tors or the looped end of a conductor. It is to be noted that the curvatures of the registering grooves correspond and altho in this illustration they have been shown to all be identical to meet the condition of terminating the looped end of a single conductor, the registering grooves of one pair need not correspond to the registering grooves of the other pair as would be the case if two wires of different size were being connected.

A retaining means in the form of a washer 35 of a resilient material such as Neoprene snugly fits the bolt and prevents disengagement of that bolt from the basic member while the conductors are being positioned in the respective pairs of grooves. The various parts likewise cannot become misaligned during this phase of an operation.

After the conductors have been located in their respective pairs of grooves, the bolt 15 is threaded into the threaded hole 24 in the cap member and both bolts 15 and 16 are then manipulated until both are drawn tight whereupon the clamp'is complete and the conductor or conductors are secured therein.

it should be noted here that the ends of the wire bearing grooves are preferably smoothly rounded as at 36 so that no scoring of the conductor by the, edges of the grooves can occur either as the pressure is applied or from moveient of the conductors themselves relative to the clamp such as might be occasioned by line sway or flexing caused by the elements.

In Fig. 4 there is illustrated a clamp which in all respects is substantially the same as the clamp previously described with the exception that a plurality. of intermediate bar members have been provided. These are indicated by reference characters 39a and 36b. The two facing grooves 37 and 38 of the bar members 30a and 3% are illustrated as being of corresponding but smaller curvature than the facing grooves 11 and 33a and 21 and 34a which respectively correspond in size as might be expected for use in connecting a smaller distribution line or drop with larger distribution lines. The clamp in Fig. 4 is moreover shown in closed or operative position with wires or lines 39, 40 and 41 securely clamped and connected mechanically and electrically between the various members of the assembly.

From the foregoing description it. should be apparent that numerous advantages are gained in a clamp made in accordance with the principles of this invention. The arrangement of bolts, one on each side of the conductor and operating thru the especially formed clamp parts has been found to be the most efiicient means for balancing the applied pressure giving a total pressure to the conductors equal to the sum of the pressures developed by each of the bolts. The rotational forces are also balanced by this arrangement so that no stress is set. up in the guides thereby eliminating any binding action between the parts. The most advantageous amount of torque capable of being applied by hand wrenches is achieved by preferably providing the bolts with threads of the American Fine Thread Series.

It has also been found that a clamp such as provided by this invention is particularly desirable for use with aluminum conductors because of an ever present oxide film on the surface of such conductors which is a very poor electrical conductor and which unless removed can seriously affect the conductivity of the conductor. By providing a clamping means capable of exerting extremely high pressure evenly, the strands of an aluminum conductor are sufficiently distorted to disassociate the oxide film from the contact surfaces and thus provide an excellent electrical connection of negligible resistance. Heretofore known connectors require the conductor strands to be wire brushed with a special greaselike compound, to first scratch the surface and to cover it immediately to prevent reoxidation. The high pressure developed by this clamp is further desirable for terminating or dead-ending tensioned overhead conductors of aluminum. The efficiency of a clamp for dead ending depends on the amount of surface contact area that the clampcan develop with the strands of the conductor, By virtue. qf.the novelconcept 4 of the instant clamp, high pressure is distributed equally over a maximum of contact area.

The shape requirements of the grooves for the multiple purposes uses of this clamp as noted have been found to be complementary, that is a shape that equally distributes a. generous amount of contact area among as many strands of the conductor as possible has been discovered to be a criterion for both good conductivity as well as efiicient holding power.

it should be noted as a distinct advantage that all parts of this clamp are interchangeable and by providing bar members with different curvatures in the grooves on either side, any combination of wire sizes may be efficiently clamped together.

Ry provision of guides integral with one of the members and associated with all the other parts, alignment and slidabie movement is achieved so that easy entrance of the conductors to be clamped is afforded as well as the ability to apply the pressure to the members and the conductors without disassembly of the parts. This is particularly advantageous when applying the clamp to high voltage lines where hot-line tools are used.

Moreover the clamp may be made of almost any suitable metal or alloy and which can be chosen to correspond to the properties of the conductors to obviate ditficulties encountered due to different ratcs of thermal expansion of metals of diifering properties, so that good high conductivity connections can be maintained notwithstanding the severe temperature cycles which are encountered on overhead systems or high lines.

it will be apparent therefore that the clamp described is capable of serving multiple purposes to great advantage. It should also be understood that altho only a preferred embodiment has been described, such modifications as will be suggested to those skilled in the art and coming within the spirit of the invention are intended as being within its scope as best defined by the appended claims.

We claim:

1. A line clamp comprising outer rigid metallic members non-rotatable with respect to one another yet relatively movable toward and away from each other and each being provided with a line bearing groove, at least one additional rigid metallic member intermediate said outer members, relatively movable toward and away therefrom and provided with line bearing grooves in opposite surfaces respectively in register with the corresponding rooves in the adjacent members, means including at least one elongate guide rail integrally connected to one of the outer members centrally and to one side only thereof cxtending substantially the full height of the clamp adapted to maintain in register the line bearing grooves of all of said members at all times in said relative movement and to permit insertion of conductors into said registering line bearing grooves fromthe side opposite said guide rail, and means disposed on opposite sides of said line bearing grooves in the members for exerting a high pressure to draw said members together to tightly grip lines disposed in the registering pairs of grooves and to maintain them so clamped under high pressure.

2. A line clamp comprising outer rigid metallic members non-rotatable with respect to one another yet relatively movable toward and away from each other and each being provided with a line bearing groove, at least one additional rigid metallic member intermediate said outer members relatively movable toward and away therefrom and provided with line bearing grooves in opposite surfaces respectively in register with the corresponding grooves in the adjacent members, means including a pair of parallel elongate guide rails integrally connected to one of the outer members centrally and to one side only thereof extending substantially the. full height ofthe clamp adapted to maintain in register the line bearing grooves of all of said members at all times in said relative movement and to permit insertion of conductors into said registering line bearing grooves from the side opposite said pair of guide rails, bosses centrally disposed on opposite sides of said line bearing grooves in the outer members, and means comprising a pair of bolts slidably extending thru the bosses in one of the outer members and threadedly extending into the bosses of the other one of 5 the outer members.

References Cited in the file of this patent UNITED STATES PATENTS Grover June 26, 1934 10 Lee Mar. 10, 1936 Bergan Apr. 23, 1940 Rogofi Jan. 26, 1943 Birkenmaier Sept. 2, 1947 Van Ryan Dec. 16, 1947

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