US1890350A

US1890350A - Strain relief fitting

Info

Publication number: US1890350A
Application number: US513445A
Authority: US
Inventors: Lenjamin C Webster
Original assignee: Bryant Electric Co
Current assignee: Bryant Electric Co
Priority date: 1931-02-04
Filing date: 1931-02-04
Publication date: 1932-12-06
Anticipated expiration: 1949-12-06

Description

f atented Dec. 6, 1932 UNITED STATES PATENT OFFICE faEN-TAHIN C. WEBSTER, OF SOUTHPORT, CONNECTICUT, ASSIGNOR TO THE BRYANT ELECTRIC COMPANY, OF BRIDGEPORT, GONNECTIGU T, A CORPORATION OF CONNECTI- CUT s'rmm RELIEr rrr'rme Application filed February 4, 1931. Serial at. 513,445.

This invention relates to electric fittings for relieving the strain of the conducting cable u on the .contacts of an electric connector. T e invention is particularly useful in con- 6 nection with attachment plugs, rosettes,

socket caps and the like.

It is an object of my invention to make an electric connector with a strain relief fitting composed of a few easily made parts and thus to simplif and reduce the expense of manufacture 0 this type of electric device. An-

other object is to make an electric connector with strain relief members which engage directly with the insulating portion of the connector whereby the construction as a whole tion.

Fig. 3 is an elevation section view of the plug shown in Fig. 1 with the section taken on line 33 of Fig. 1. m

Fig. 4 is a plan view, partly in section, of

50 the plug shown in Fig. 1 with one of the strain relief members removed.

Figs. 5, 6 and 7 aredetailed plan and eleva- 7 tion views of one of the strain relief members used in my invention.

Referring to the drawing, the invention is shown, byway of example, when used with an attachment plug which comprises an in sulating body 10 which as shown is approximately in the form of a spherical segment of two bases, but obviously this body may be of any convenient form. The larger base, which may be termed the contact face of the insulating body 10, is recessed as at 11 to accommodate the conventional prong contacts 12 as in the attachment plugs of the prior art.

The insulating body 10 is centrally bored as at.

14 to permit the passage of an insulated electric cable 16 in which are the feed wires 16a,

16b for connection to the prong contacts of the plug: At diametrically opposed points on the outside surface of the insulating body are cut channels 18 which run from the smaller or upper base of the insulating body (see Figs. 2 and 3) directly down its outside surface to its contact face. These channels follow a substantiallycircular path as shown in Fig. 3, and they widen out abruptly adj acent the contact face, forming recesses 19a, 19b, in which lie feet 20 which extend laterally from one end of each of identical strain relief members 22. These strain relief members 22 are made of stamped sheet metal and are curved to follow the circumferentially arcuate curvature of the channels 18. The other end portion of each of the members 22 is formed into a cable gripping jaw 25 stand- 1 ing up perpendicularly to the top of the plug adjacent the bore 14, when the member is lying in the channel 18. Laterally extending from these end portions are apertured arms 23, through the apertures of which screws 24 pass whereby to clamp these jaws to, the cable 16. Encasing the insulating body." and the portions of the strain relief members which lie in the channels 18 is a metallic cover or armor casing 28 which fits around the il'lSll? lating body. The casing is opened at its top to permit the passage therethrough of the jaws of the strain relief members and the casing is open at its bottom to permit the pasflange 29 on the casing is turned over parallel to the contact face of the insulating body so asto hold the body within the casing and at the same time to hold the members 22 with their feet 20 seated in the recesses 19a, 19?), this by reason of the inner periphery of the casing lying adjacent the feet 20.

From the foregoing it will be seen that when the plug is assembled, the strain relief members 22 are placed in the channels 18 with the feet 20 lying in the lateral recesses 19a, 19?). Then the--casing 28 is fitted over the insulating body and the flange 29 is turned over thereby holding the parts together. When it is desired to connect the plug to an electric cable, the cable is passed between the jaws of the strain relief members. and through the aperture 14 so that the conductors 16a, 16?), may be connected to the is oi 2% I 'rseoeso prong contacts 12. Then the binding screws 24 are tightened causing the jaws of the strain relief mer'nbersto grip the cable. Now any pull on the cable will be transmitted to the strain relief members and through them directly to the insulating body since the feet 20 engage with the sides of the recesses, 19a, 195.

Although I have shown my invention as aplied to an attachment plug it will be understood that the invention is not limited to this use. Obviously it may be readily applied to electric connector devices generally.

Various changes in form within the scope of my invention will occur to those skilled in the art, therefore I do not limit myself to the exact form of the parts as shown.

Iclaime 1-. An "electric fitting comprising an insulating body having diametrically opposed channels in the surface thereof, said channels having lateral recesses, strain relief members lying in said channels and having laterally extending feet lying in said recesses, said strain relief members also having jaws adapted to grip an electric cable, and a cover encasing said insulating body and holding said strain relief members there- 2. An electric fitting comprising an insulating body having diametrically opposed channels in the surface thereof, said channels having lateral recesses, strain relief members lying in said channels and having laterally extending 'e-et lying in said recesses, said strain relief members also having jaws adapted to grip an electric cable, and a cover encasing said insulating body and holding said strain relief members thereon, said cover being provided with an inwardly turned flange to hold said cover and insulating body together. i

3. An electric fitting coniprising an insulating body having diametrically opposed curved channels on the surface thereof, strain relief members having portions curved com 'plementally to said channels and lying there in, said channels having lateral recesses and said strain relief members having feet in said recesses and a cover encasing said insulating body and holding said feet in said recesses.

4. An electric fitting comprising an insulating body having diametrically opposed curved channels on the surface thereof, strain relief members having portions curved complementally to said channels and lying there- 1n, said channels having lateral recesses and said strain relief members having feet in said recesses, and a cover encasing said insulating body and holding said'feet in said recesses, said cover having an inwardly turned flange lying parallel and engaging the bot tom of said insulating body.

5. An electric fitting comprising an insulaing body having diametrically opposed channels in the surface thereof, said channels being curved substantially along the circumference of a circle and havin lateral recesses, strain relief members lylng in said channels and having laterally extending feet lying in'said recesses, said strain relief members also having jaws adapted to grip an electric cable, and a cover encasing said insulating body and holding said strain relief 1 BENJAMIN C. WEBSTER.