Electrical terminal

.May 21, 1940.

2,201,674

R. N. ROWE ET AL

ELECTRICAL TERMINAL

Filed March 12, 1938

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Patented May 21, 1940

2,201,674

UNITED STATES PATENT OFFICE

2,201,674

ELECTRICAL TERMINAL

Raymond N. Rowe, Plainville, and John L.

Robertson, Forestville, Conn., assignors to The Trumbull Electric Manufacturing Company, Plainville, Conn., a corporation of Connecticut

Application March 12, 1938, Serial No. 195,488

Claims. (Cl. 173—269)

Our invention relates to devices for connecting wires or cables.

The main object is to provide a rugged terminal with effective clamping means, the parts of which can be readily assembled.

A special object is to provide means for connecting the rotatable Clamp screw or nut and the clamp shoe so that they can be assembled and handled as a unit and removed as a unit from the ^; housing or body.

Another object is to provide a device of this character in which the clamp shoe is movable with the threaded nut and can be readily released and retracted from the cable or entirely removed from the housing or terminal.

Fig. 1 is a longitudinal sectional view of one form of terminal involving our invention.

Fig. 2 is a plan view of the same.

Fig. 3 is a cross sectional view of the same.

Fig. 4 is a sectional view of the clamp screw or nut.

Fig. 5 is an exploded perspective view of parts of the device.

Fig. 6 is a view of the underside of the clamp > shoe or saddle showing a transverse rib which may be employed.

The main body or housing 7 of the device may be formed of a single piece of metal with a recess or passage 8 to receive the cable, conductor or circuit wire 9, which is quite frequently of the multi-strand type.

The diameter of the recess will ordinarily be enough larger than the cable to conveniently receive it. It will be found however that the terminal will accommodate considerably smaller conductors. —

The inner face 12 of the shoe 10 is preferably concave so as to embrace the top and sides of the cable. The clamp screw or nut 13 is adjustable In the threaded socket 14 in the terminal body and presses against the clamp shoe 10 to force it against the conductor 9.

The axis of the passage or socket 14 intersects the axis of the cable or conductor recess 8 and the walls of the passage 14 and recess 8 are uninterrupted circumferentially around the mouth of each. The side walls of the screw threaded passage 14 are continued into the recess 8 in the form of grooves ί I to accommodate the screw and the side extensions of the clamp shoe 10 and permit the shoe to be inserted into the passage 14 before the cable is inserted. This also allows the shoe to tilt slightly and accommodate itself in the passage to the cable end.

We have found, however, that it is highly de sirable that the shoe be secured to the clamp screw not only for convenience in keeping the parts together in handling but also to facilitate retraction and removal of the shoe. As the result of considerable study and experimentation we s have discovered a very simple solution of the problem.

The clamp screw 13 preferably has a central recess IS for the insertion of a wrench. This recess extends through the screw and at the inner 10 end a recess 16 of larger diameter is provided to receive the edge of and form a seat for a metal disc or washer 17. This disc may be secured to the clamp screw by swaging, spinning or staking a portion or portions 18 of the lower face of the IS screw over the edges of the disc. The rim 19 of the clamp screw extends slightly below the disc so that the solid part of the screw engages the upper face of the shoe 10 when the screw is tightened against it. 20

The clamp shoe or saddle is pivoted to the disc 17 and thus to the screw 13 by a pivot member 20 which passes through the central hole 21 in the shoe 10 and the central hole 22 in the disc 17. The upper edge of the hole 21 is preferably de- ₂s pressed or countersunk to receive the depressed central portion 23 of the disc so as to assist in aligning or centering the shoe and the screw and to prevent any pressure being transmitted to the disc. The pivot member 20 is preferably in the ₃₀form of a rivet, the upper end of which fits loosely in the depressed center of the disc 17 and the lower end fits in a recess 24 in the under face of the shoe so that it wiU not interfere with the engagement of the shoe with the cable or conductor. ₃₅The upper ends of the rivet member 20 are bent over in the depression in the disc 17 as shown in Figs. 1 and 2 so as not to project as far as the upper flat surface of the disc and so as to be clear of the end of any tool which may be inserted in ₄₀the opening 15 in the screw 13.

The depressed central portion of the disc and the countersunk portion of the hole 21 in the shoe or saddle 10 are so arranged as to provide a free bearing for the shoe until the shoe is pressed hard 45 enough against a cable to force the upper face of the shoe against the lower face of the clamp screw or nut 13 as is necessary in order to securely clamp a cable in position. Thus all of the operating strain is taken up by the clamp screw and the shoe or saddle.

The clamping action of this device is similar to that of the prior Patent 2,068,152 but the improvements make it easier to handle as the shoe

3,201,874 and screw are connected together and cannot be accidentally separated or mislaid.

It also has the great advantage of ease of retraction and removal. If the shoe is wedged or sticks in the housing or against the cable it may be loosened and withdrawn by the usual action of loosening and removing the clamp screw or nut.

For manufacturing reasons it is ordinarily 10 preferable to make the clamp screw 13 with a broached hexagon hole passing entirely through the screw and to provide the necessary bottom in the hole in the form of a separate disc as shown but the bottom of the hole may be closed in any suitable manner.

An important advantage of securing the saddle and the screw or nut together in this manner is that these parts are held together in alignment and thus cannot “cock”, wedge or jam while a cable is being secured in position in the lug and the pivotal connection allows the saddle or shoe to rotate sufficiently to align with the cable.

It will be noted that the body or housing is rugged and that the walls of the conductor recess ; at its entrance are continuous or undivided. The same condition will be found at the inner end of the recess. As a result the body has a maximum strength to resist the pressure of the clamp screw and shoe against the cable end. The screw passage also has a continuous or undivided wall surrounding it so as to afford maximum strength. These features are important as the parts should not be any heavier than necessary and yet must withstand considerable stress when a cable end is securely clamped in place.