US2533897A - Ground clamp - Google Patents

Description

Dec. 12, M D, REDDQCK 2,533,897

GROUND CLAMP Filed May 10, 1946 "Him 2/ l 2/ llmml l/l, '2;

INVENTOR Moi/m & izmacr ATTORzEY Patented Dec. 12, 1950 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to what are generally known as ground clamps for use in grounding electric wires. More particularly, the invention deals with a clamp of the class described composed of three sheet metal stampings, two of which are adapted for clamping engagement upon a pipe or other ground support and the third adapted for clamping engagement with one of the first stampings in clamping a conductor as well as the armor of a conductor therebetween. The novel features of the invention will be best understood from the following description when taken together with the accompanying drawing in which certain embodiments of the inven tion are disclosed, and in which the separate parts are designated by suitable reference characters in each of the views, and in which:

Fig. 1 is a plan view of the clamp.

Fig. 2 is a section on the line 2-2 of Fig. l; and

Fig. 3 is a section on the broken line 3--3 of Fig. 1.

In production of ground clamps of the kind under consideration, it has been customary to employ a fairly substantial clamp member as one of the parts in establishing a clamping engagement with the ground support and such things as castings and forgings have been used. Devices of this type and kind have been expensive and quite heavy in construction, from a standpoint of shipping costs. vention is to provide a light weight and yet strong and durable ground clamp construction made from sheet metal stampings, thereby materially reducing the cost of production of the device.

My improved ground clamp comprises two primary clamp plate I9 and II and a supplemental clamp plate I 2. The plate I! is in the form of a sheet metal strap having an offset central V-portion I3, inner surfaces of the inclined walls 14 of which are provided with notches, as at I5, to provide gripper surfaces to grip a pipe, tube or other support, indicated in dot and dash lines at II; in the drawing. The laterally extending wing end I! of the plate II have threaded apertures I8 to receive clamp bolts I9 which pass freely through apertures 29-49 in corresponding wing ends 2| of the plate I9. The aperture 29 differs from the aperture 29 in opening out through one side of the plate, as seen at 22 in Fig. l of the drawing, thus providing for the swinging 0f the plate I9 with respect to the plate I I without completely detaching the screws or bolts I9 from the plate II in making an assemblage.

The purpose of my in- U The plate In has a central V-portion 23 having transverse grooves 24 on the inner surfaces of the walls 25 thereof, similar to the grooves I5 for grouping the support I6. The walls 25 are cutout, as seen at 26, note Fig. 2, to form another pair of smaller wings 27, having threaded apertures 28 for the reception of clamp screws 29. It will also appear from a consideration of Fig. 2 of the drawing, that the upper end of the V- portion 23 has centrally thereof a longitudinal groove or depression 39 which aids in keying a conductor wire 3| and the armor 32 thereof within and between the plates I9 and I2, as is clearly illustrated in Fig. 3 of the drawing, and also indicated in clamping the wire 3| in Fig. 2 of the drawing.

The plate I ll differs from the plate I I in having a lateral extension 33, best shown in Fig. 9 of the drawing, this extension having a pair of oppositely directed wings 34 which are of greater width than the wings 2'1 and have threaded apertures similar to the apertures 28 for the reception of screws 35. The groove 39 passes through the lateral extension 32, as clearly seen in Fig. 3 in maintaining the key engagement with the armor 32. It will be understood that the plate I9 is also a sheet metal stamping and this applies to the plate I2. The plate I2 is generally of the shape shown in Fig. 1 of the drawing and. has a small pair of wing portions 36 disposed over the wings 21 and apertured for reception of the screws 29. The plate I21 has a longer set of wings 31 disposed over the wings 21 and apertured for reception of the screws 29. The plate I2 has a longer set of wings 31 disposed over the wings 34 and apertured for the reception of the screws 35. The plate I2 has a narrow central V-portion 38 for clamp engagement with the conductor 3| and a wider V- portion 39 for clamp engagement with the armor 32. The V-portion 39 also has a transverse inwardly extended notch or bed 40, note Fig. 3 to engage between the recess portion of the armor 32, as clearly seen in Fig. 3 of the drawing to retain the armor against displacement from the clamp. The purpose of this construction is to establish a ground connection with the armor, as is required in many of the electrical codes.

In attaching the clamp to a support, screws I9 are adjusted in the plate I I to a position to allow the plate I9 to swing over the support, after which the plate I 0 or the opening 29' thereof is brought into engagement with the screws or bolts I9, and the screws or bolts I9 are then tightened to securely fix the clamp to the support, as at I6. In like manner, the screws 29-35 are loosened sufliciently to provide free insertion of the conductor 3| and armor 32 and then these screws 29 and 35 are tightened to secure the conductor and armor to the ground clamp.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

In a ground-wire fitting comprising two'body members substantially V-shaped in cross-section, each member having two flanges, releasable means for securing said members in unitary relation, said members being assembled with said V-shaped portions facing in opposite directions and. being movable to or away from each other to permit mounting said members upon a pipe of large or small diameter, one of said V-s'haped members having a flanged extension and an elongated notch ex ending throughou the 4 height of said member, a cap having a large recess and a small notch, said recess and notch being longitudinally aligned and laterally offset from each other, and means for aligning said cap recess and notch with said notch in said V-shaped member and to cause said cap to clamp an electric cable and its bare wire to said notched V-shaped member simultaneously and in a single straight line.

MORRIS D. REDDOCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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