Title:
Cable terminating means
United States Patent 2379942


Abstract:
This invention relates in general to cable terminating apparatus and more particularly to electrical connectors for connecting flexible high potential cables to the apparatus with which they are to be associated. In electrical cables and connectors for use at high potentials, it is well known...



Inventors:
Webber, Carroll A.
Application Number:
US47083542A
Publication Date:
07/10/1945
Filing Date:
12/31/1942
Assignee:
BELL TELEPHONE LABOR INC
Primary Class:
Other Classes:
174/73.1, 174/88C, 174/102SC, 174/351, 174/359, 200/51R, 439/578
International Classes:
H01R13/621
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Description:

This invention relates in general to cable terminating apparatus and more particularly to electrical connectors for connecting flexible high potential cables to the apparatus with which they are to be associated.

In electrical cables and connectors for use at high potentials, it is well known that breakdown of the insulation often occurs as the result of corona discharges through entrapped air pockets which in turn form ozone and cause deterioration of the rubber or other insulating medium. This is particularly true in the case of cables and terminating means for high potential equipment to be used in aircraft which are adapted for flying at high altitudes since under such conditions corona occurs at much lower voltages than when operating at altitudes near sea level. For such apparatus it is not only required that there be freedom from corona at high altitudes under the required operating conditions, but it is also desirable that the equipment be small in size in order to keep weight and bulkiness at a minimum.

It is, therefore, an object of the present invention to provide cable terminating means for flexible high potential cables in which corona discharges do not occur even under severe operating conditions.

It is a further object to provide such equipment of a size and weight which are kept at a minimum value.

To accomplish these and other objects and in accordance with the features of the invention, there is provided a terminating means including a connector in which the conducting terminal members are surrounded with a sheath of resilient conducting material which in turn is surrounded by and in such intimate contact with a relatively thick sheath of insulated material so that no corona discharges occur between the conducting element and the insulating sheath.

In accordance with another feature, the adjacent faces of the cooperating resilient members are so shaped that as these members are forced together the area of contact increases gradually from the center to the perimeter thus forcing out al air particles which might otherwise cause corona dificulties particularly at or near the axis where the electrical stresses are highest.

These and other features of the invention may be more clearly understood by reference to the accompanying drawing, in which: Pig. 1 is a view, partly in section, of a connector embodying features of the invention together with its associated cable sections; Fig. 2 is a similar view in section and with the cooperating members out of engagement; and Fig. 3 is a partial view of a modified structure.

Referring to the drawing, the high potential shielded cable sections 5- are terminated by a connector, including a plug member 6 and a jack member 7 provided with suitable terminal contact members 8 and 9 respectively. Each cable section comprises a conductor 10 which preferably is stranded as shown, surrounded by a thin layer II of conducting rubber or similar conducting material and a relatively thick layer or sleeve 12 of insulating rubber over which is placed a second thin layer 13 of conducting rubber. A metallic braiding or shield 14 closely surrounds the conducting layer 13 and it in turn is surrounded by a textile braid or covering 15.

The jack member 9 is connected to its respective conductor 10 and is then provided with a layer i of resilient conducting rubber which is only partially vulcanized. A dished washer or disc 17 is then placed over the layer 13 of conducting rubber and the braided shield 14 is soldered thereto as shown at 18. In order to overcome any unequal stresses which might be caused by the edges of washer 17, the layer 13 extends a suitable distance beyond the washer 17. The cable section 5 with the washer 17 and jack 9 assembled as shown in Fig. 2, is then placed in a suitable mold together with a metallic sleeve member 19 and a heavy layer or sleeve 20 of resilient insulating rubber or similar material is molded within the sleeve and is provided with a tapered end portion 21 extending over the cord end to prevent excessive bending at that point. During the molding operation, the required vulcanization of layer 16 is completed. One end of sleeve 19 is provided with a threaded portion cooperating with clamping nut 22 having a flanged or seat portion 23 which serves to engage that portion of washer 17 projecting out of the insulating sleeve 20 and clamps it securely against the end of sleeve 19.

Thus not only are the parts securely clamped together but a good electrical contact is provided between the braided shield 14 and the metallic sleeve 9I. A flange 24 is provided to facilitate mounting the member 7 to a panel, not shown.

The plug member 6 is formed in a manner similar to that of jack member 7. Terminal contact member 8 is soldered or otherwise secured to the conductor 10 of a corresponding cable section and over the greater portion of its length it is surrounded by a sheath 25 of resilient conducting rubber. A dished washer 26 is secured in position about the bared conducting layer 13 and soldered to the braided shield 14. The parts thus assembled are then placed in a suitable mold together with a sleeve member 27 and a thick sheath or sleeve 28 of resilient insulating rubber is molded in place. An end clamping nut 29 is provided to clamp the washer 28 and sleeve 27 firmly together. The outer diameter of the end portion 30 of sleeve 27 is such as to provide a sliding fit with the inner diameter of the end portion 31 of sleeve 19 and central clamping nut 32 bearing against shoulder 33 and cooperating with the threaded portion 34 of sleeve portion 31 serves as a member for drawing the plug member and jack member 7 together gradually and with the necessary force. The end surface 35 of sheath 25 and sleeve 28 is convex with respect to the end surface 36 of sheath 19 and sleeve 20 so that as the members are drawn together by means of central clamping nut 32 to cause the plug contact member 8 to engage the jack contact member 9, the area of contact between surfaces 35 and 36 is first made at the center and increases outwardly in a uniform manner thus forcing out all air particles and preventing the formation of any air pockets which would promote corona discharges under severe operating conditions. As shown, the surface 35 is convex and the surface 36 is plane. Obviously, the same result of forcing out the included air will be obtained if both surfaces are convex or if one surface is convex and the other surface is concave but has a greater radius of curvature so that one surface remains convex with respect to the other. Also provided the convex surface 35 has sufficient resiliency, the plane surface 36 need not be of resilient material.

In accordance with the modification disclosed in Fig. 3, a ring 37 of conducting rubber is molded, as shown, in the sleeve 28 as a further precaution in preventing corona discharge between the sleeve 28 and the end portion 30 of sleeve 27.

When following this construction, a similar ring of conducting material, not shown on the drawing, would be provided on the corresponding outer portion of surface 36 of the jack member. The terminating means, as disclosed, has been found to overcome to a large degree the trouble from corona discharges occurring in the larger and more cumbersome devices used heretofore and to thus operate satisfactorily with associated apparatus at higher potentials and at much higher altitudes.

What is claimed is: 1. An electrical connector for joining two sections of high potential flexible cable comprising f a pair of cooperating terminal members each having a layer of resilient conducting material positioned thereabout surrounded by a relatively thick sheath of resilient insulating material, the adjacent end surfaces of said layers and sheaths being easily compressible, the end surface of one member being convex with respect to the end surface of said other member, and means for forcing said members together and compressing said adjacent end surfaces. 2. An electrical connector for joining two sections of high potential flexible cable comprising a pair of cooperating terminal members each having a layer of resilient conducting material positioned thereabout surrounded by a relatively thick sheath of resilient insulating material, the adjacent end surfaces of said layers and sheaths being easily compressible, the end surface of one of said members being convex and the end surface of the other of said members being planar. 57 and means for forcing said members together and compressing said adjacent end surfaces.

3. An electrical connector for joining two sections of shielded flexible cable comprising a pair of cooperating terminal members each having a layer of conducting material positioned thereabout and surrounded by a relatively thick sheath of insulating material, the adjacent end surfaces of one of said layers and sheaths being easily compressible, the end surface of one of said members being convex with respect to the end surface of the other of said members, and means for forcing said members together and compressing said adjacent end surfaces.

4. An electrical connector for joining two sections of shielded flexible cable comprising a pair of cooperating terminal members each having a layer of resilient conducting material positioned thereabout surrounded by a relatively thick sheath of resilient insulating material, a sleeve of conducting material surrounding said thick sheath of resilient insulating material and electrically connected to the shield of the respective cable section, a ring of resilient conducting material positioned at the outer peripheral edge of said sheath and adapted to engage said metallic sleeve when compressed, the adjacent end surfaces of said layers and sheaths being easily compressible and one of said end surfaces being convex with respect to the other of said end surfaces, and means for forcing said members together and compressing said adjacent end surfaces.

5. An electrical connector comprising a pair of cooperating members and means for clamping said members together, each of said membeis comprising a contacting terminal member, the non-contacting portion of which is surrounded by a layer of conducting resilient material in intimate contact with a relatively thick sheath of resilient insulating material, the end surface of said resilient layer and sheath of one of said members being convex with respect to the end surface of said resilient layer and sheath of the other of said members, whereby as said members are drawn together by said clamping means the area of contact between said end surfaces is gradually increased outwardly from the center thus expelling air particles between said end surfaces.

6. An electrical connector comprising a pair of cooperating members and means for clamping said members together, each of said members comprising a contacting terminal member, the non-contacting portion of which is surrounded by a layer of conducting resilient material in intimate contact with a relatively thick sheath of resilient insulating material, the end surface of said resilient layer and sheath of one of said members being convex with respect to the end surface of said resilient layer and sheath of the other of said members, whereby as said members are drawn together by said clamping means the area of contact between said end surfaces is gradually increased outwardly from the center thus expelling air particles between said end surfaces, said clamping means comprising a pair of metallic sleeve members securely fixed to the respective sheaths of resilient insulating material and a clamping nut adapted to bear against a shouldered portion of one of said metallic sleeves and engage a threaded portion on the other of said metallic sleeves.

7. An electrical connector for making detachable electrical connection between two sections of high potential cable, each section comprising a metallic conductor, a thin coating of resilient conducting material thereover, a relatively thick sleeve of insulating material over said layer, a thin layer of resilient conducting material over said insulating sleeve and in intimate contact therewith and a metallic shield over said outer layer of conducting material, said connector comprising a pair of cooperating members and means for securely holding said members in engagement, each of said members comprising a terminal contact member connected to its respective cable conductor, a metallic disc positioned about said outer layer of said conducting material, a sleeve of resilient conducting material surrounding at least a portion of said terminal contact member, and a relatively thick layer of resilient insulating material surrounding said conducting layer, the end surface of one of said members being convex with respect to the end surface of the other of said members.

8. A cable terminating means comprising a cable section having a terminal sleeve of resilient ,insulating material fitted over one end of said section, a metallic disc molded in said sleeve and having its peripheral edge projecting out through the periphery of said sleeve to provide a rigid flange secured to said sleeve, a metallic coupling sleeve snugly fitting over said resilient sleeve, and a clamping nut fitting over and providing a seat for the projecting portion of said disc and engaging threads on said metallic sleeve thereby clamping said disc against one end of said metallic sleeve and locking said resilient sleeve in saiid metallic sleeve.

9. A cable terminating means for shielded electrical cables comprising a cable section having a terminal sleeve of resilient insulating material fitted over one end of said section, a metallic disc molded in said sleeve and having its peripheral edge projecting out through the periphery of said sleeve to provide a rigid flange secured to said sleeve, said disc being electrically connected to a metallic outer shield on said cable section, a metallic coupling sleeve snugly fitting over said resilient sleeve, and a clamping nut fitting-over and providing a seat for the projecting portion of said disc and engaging threads on said metallic sleeve thereby clamping said disc against one end of said metallic sleeve, locking said resilient sleeve to said metallic sleeve and providing an electrical circuit from said cable shield to said metallic sleeve.

10. A cable terminating means for shielded electrical cables comprising a pair of cable sections each having a terminal sleeve of resilient insulating material fitted over one end of one of said sections, a metallic disc molded in said sleeve and having its peripheral edge projecting out through the periphery of said sleeve to provide a rigid flange secured to said sleeve, said disc being electrically connected to a metallic outer shield on said cable sections, a metallic coupling sleeve snugly fitting over said resilient sleeve and a clamping nut fitting over and providing a seat for the projecting portion of said disc and engaging threads on said metallic sleeve thereby clamping said disc against one end of said metallic sleeve, locking said resilient sleeve in said metallic sleeve and providing an electrical circuit from said cable shield to said metallic sleeve, and means for forcibly connecting said cable sections together, said means comprising a coupling nut engaging a shouldered portion on one of said metallic sleeves and a threaded portion on the other of said metallic sleeves.

CARROLL A. WEBBER.