US2755451A

US2755451A - Connector for electric cables

Info

Publication number: US2755451A
Application number: US349748A
Authority: US
Inventors: Keith A Smyers
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-04-20
Filing date: 1953-04-20
Publication date: 1956-07-17
Anticipated expiration: 1973-07-17

Description

July 17, 1956 K. A. SMYERS CONNECTOR FOR ELECTRIC CABLES Filed April 20, 1953 United States This invention concerns a connector for electrical wires carrying electrical impulses for the propagation of sound.

The principal use of this connector is for securely holding and clamping electrical connectors carrying audio impulses through wires which include a central stranded conductor and insulating sheath surrounding this and a sheath of metallic braided wires surround the insulation sheath. This structure may be included within a second insulation covering. 7

One of the objects of the invention is to provide a connector which will hold stranded wire of the type above mentioned securely and firmly so that the contacts within the connector can not be loosened by ordinary rough usage or even extraordinary abuse.

A second object is to provide a compact connector having metallic body which will securely hold flexible electric cable and provide secure contacts with a central conductor within the cable and a flexible metallic sheath outside of the central conductor.

1 attain the foregoing objects by means of the particular construction, devices and combination of parts shown in the accompanying drawings in which Figure 1 is a side elevational center section of the connector in assembled form and with a stranded cable held in place.

Figure 2 is a transverse section of the connector taken substantially on line 2-2 of Figure 1.

Figure 2a is a transverse section taken substantially on line 2--2 of Figure 1 but showing the holding keys in an expanded position to release the cable.

Figure 3 is a transverse section taken substantially on line 3-3 of Figure 1; and

Figure 4 is a plan view of the inner end portion of the head bolt and lock nut which hold the stranded conductor.

Similar numerals refer to similar parts in the several views.

The body 3 of the connector is made of metal and has a bore 20 at the outer or connecting end and a bore 24 at the inner or cable clamping end. The end portions of both bores are threaded. An end plug 1 threads into the end of bore 24 and is provided with a central hole 18 at its outer end to receive cable 17, an outwardly extending bore 18a to receive keys 2, and a taper bore 22 joining bores 18a and 18. The unbored space between

bores

20 and 24 is centrally drilled with a small hole 19 to receive the inner portion of cable 17.

Head 4 is threaded into the outer end of bore in body 3. This head carries a head bolt connector 9 which is centrally positioned by insulating washers 6 and 7 which are secured by axial conductor screw 8. When head bolt connector 9 is secured in head 4 and the latter threaded into body 3 the head bolt connector is concentrically positioned within a central inwardly opening bore 4a of head 4 and securely kept out of contact with the metal body portion of said head.

The inner end of head bolt connector 9 is reduced in size and provided with a threaded portion 9a which has a longitudinal groove 12 to receive the stranded lead atent- Q ice wire 14. At the base of threads 9a there is a taper or angular annular shoulder 11. The lock nut 10 screws on to threads at 9a and holds the end portion of lead wire 14 in place in groove 12 and clamps it against tapered shoulder 11. This nut has a tapered inner face 23 which conforms to shoulder 11 and clamps the end of conductor 14 securely against shoulder 11.

At the cable clamping end of body 3 and in order to firmly secure cable 17, I provide two keys indicated by

numerals

2, 2. These keys are beveled from their outer edges toward their inner edges at each end and slidably fit into grooves 13, which may be termed key way slots,

and are formed on the inner annular face of bore 24 of body 3.

At the inner end of bore 24 there is a taper 21 which is aligned with the taper 22 within the central bore of end plug 1. When end plug 1 is screwed into the threadthe braided'wire sheathing 16 of cable 17. Since the inner faces of keys 2 can be made long relative to the diameter of body 3 an adequate clamping surface is provided so that the clamped portion of cable 17 is securely held. This clamping action securely holds the sheathed portion 16 of the cable, and also grounds it to the body 3. The outer insulated portion of cable 17 extends out: ward through hole 18.

The outer end of head 4 is enlarged and threaded to. hold attaching collar 5, when desired, or to permit it to thread onto a male connector plug 5a (shown in dotted lines). Collar 5 may also be threaded inwardly over and beyond the threads on head 4 so that it loosely surrounds body 3, and a female connector (not shown) may be screwed onto the threads on head cap 4.

In use the outer insulated covering of cable 17 is removed to expose a length of the braided wire sheathing 16 sufiicient to contact keys 2. The insulation 15 on the end portion of the cable is then removed for a distance sufficient to expose the stranded lead wire 14 to fit into groove 12 on head bolt 9 and to extend over the tapered shoulder 11. Sufiicient insulation 15 remains to extend through hole 19 and insulate the lead 14 from body 3.

Head 4 is removed from body 3 and end plug 1 and, body 3, in untightened relation, are then slipped onto cable 17.

The exposed stranded conductor 14 is held in groove 12 and against shoulder 11 While lock nut 10 is tightened, to make a secure mechanical and electrical connection to bolt 9. The lead Wire 14 is thus connected to the head. bolt 9 and axial conductor screw 8. After the above described lead wire connection is made body 3 is brought toward head 4 and threaded onto it. During this process the keys 2 are loose and in opened position as shown in Figure 2a. After body 3 is threaded onto head 4 the keys are clamped onto the exposed stranded sheathing 16 of cable 17 by tightening end plug 1 in the threaded inner end of bore 24. When these keys tighten onto this portion of the cable they hold the entire cable firmly in place. The stranded lead 14, is maintained straight and substantially taut as shown in Figure 1, so that it does not contact body 3. Also, the entire cable, including the outer insulated covering, which is held securely in hole 18, is firmly secured within body 3. The keys electrically ground the sheathing 16 to the case 3, and any exterior contact with body 3 will not interfere with electrical circuits passing through lead 14.

It will be noted that the above connections can be made easily and efliciently without the use of any special tools and particularly without the need for any soldered joints. Since the connection of the lead 14 to the central connector screw 8 is contained within the body 3 all joints are protected from moisture and corrosion. Likewise, since the connections between the case 3, keys 2 and sheathing 16, are contained within bore 24 they are likewise protected, and the connector is substantially water proof.

I claim:

1. A connector, for attaching a threaded connector plug to a flexible electrical cable transmitting audio frequency electric impulses and having a central lead and a braided Wire sheathing insulated therefrom, composed of a susbtantially cylindrical body having a threaded outer bore at its outer connecting end and a threaded bore at its inner cable clamping end, said last mentioned bore 'having a taper at its inner end and longitudinal keyways on its inner walls and a smaller axial bore'connesting the bores in said end portions; cable clamping keys disposed in said keyways; a threaded end plug screwed into the bore at said inner cable clamping end of said body, having an axial bore receiving said cable, and a bore within "its threaded end receiving the 'outer portions of said keys and having a taper at its bottom; said keys being compressed into said cable by'engagement'of their respective ends with said'tapers in said body and said end plug when said end plug is threaded into said inner body bore; ahead threaded into said outer bore of said body having an axial bore at its inner end and a threaded rim at its outer end to receive an attaching collar; a head bolt connector extending axially in said inner head bore, and secured therein in insulating relation to ed axially into the outer end of said head bolt connector,

securing said head bolt connector in insulated relation to said head; and an attaching collar screwed onto the outer end of said head; the head of said conductor screw providing an axial contact, insulated from said body and head and attaching collar when said collar is screwed onto said connector plug.

2. A connector, for removably attaching a flexible audio frequency transmitting cable having a central lead and an outer grounded sheathing insulated therefrom to a threaded connector fitting having a central conductor, composed of a cylindrical body having a threaded outer bore at its outer end and a threaded bore witha tapered bottom shoulder at its inner cable attaching end, provided with longitudinal keyway grooves; an end plug threaded into said bore at the cable attaching end of said body having an axial bore within its end adjacent said body said bore being tapered at its bottom and an axial bore to receive a transmitting cable extending therefrom; keys for clamping the sheathing of an audio frequency transmitting cable disposed in said keyways with their ends engaging the tapers in the bores in said body and plug, respectively, and clamping on said cable when said plug is screwed into said body; a head threaded into the outer bore of said body having an enlarged axial bore within its end adjacent said body and a smaller bore extending outwardtherefrom; ahead bolt connector having a threaded inner end portion with a longitudinal groove and a tapered shoulder, disposed in said head bore in insulating relation thereto; a locking nut screwed on said head bolt having an inwardly tapered bore adjacent thettapered shoulder on said head bolt, for securing the central conductor of said cable in said head bolt and securing it on said shoulder; and an axial conductor insulated from said head and extending from its outer ;end portion to-said head bolt; said head having a'peripheral threaded means on its outer end for attachment to a threaded connector fitting'so that the central conductor of said fitting is held in contact with said axial conduc tor'in said head.

3. A connector for removably attaching a flexible audio frequency transmitting cable having a central lead and an .outer grounded sheathing, insulated therefrom, to a threaded connector fitting having a central conductor, composed of a cylindrical body having a threaded outer end ,bore and a threaded inner end bore, ,a head having an'insu'lated axial conductor terminating in a contact head adapted to contact the central conductor of said connector fitting, a threaded outer flange provided with a collar for threaded attachment to said connector, threaded into the outer end of said body, a head bolt axially positioned within said head and insulated therefrom having an axial screw and nut for clamping said central lead of said transmitting cable, an end plug axial- 1y receiving said cable screwed into said threaded inner end bore of said body, longitudinally extending cable clamping keys compressed onto the sheathing of said cable by said end plug and securing said cable axially within said body, so that said central lead remains out of contact with said body, and said cable is retained within said "body.

Belierences Cited in the file of this patent UNITED STATES PATENTS 12 173,643 Moser Sept, 19, 1939 2 232,963 Papp et al. Feb. 25, 194-1 FOREIGN PATENTS 205,930 Great Britain Nov; 1, 1923