US2454838A

US2454838A - Plug assembly

Info

Publication number: US2454838A
Application number: US484366A
Authority: US
Inventors: Avery G Richardson; Kaplan Murray
Original assignee: Standard Telephone and Cables PLC
Current assignee: STC PLC; Federal Telephone and Radio Corp
Priority date: 1943-04-24
Filing date: 1943-04-24
Publication date: 1948-11-30
Anticipated expiration: 1965-11-30

Description

Nov. 30, 1948.

A. e. RICHARDSON EIAL PLUG ASSEMBLY Filed April 24. 1943 A TTOR/V Patented Nov. 30, 1948 PLUG ASSEMBLY Avery G. Richardson, Boonton, N. J and Murray Kaplan, Brooklyn, N. Y., assignors to Federal Telephone and Radio Corporation, Newark, N. J a corporation of Delaware Application April 24, 1943, Serial No. 484,366

3 Claims. 1

Our invention relates to a plug assembly for electric cables.

When an electric cable, such as one for carrying high-frequency currents, is connected by means of a plug to a receptacle, it is desirable to provide for the waterproofing of the connections between the conductors of the cable at its extremity and the plug terminals. It is also advantageous to design the plug assembly so that ready access to and inspection of such connections may be made with a minimum of tools.

The present invention has as an object, therefore, the provision of means for accomplishing the above results in an improved manner.

Another object of the invention is to provide a plug assembly designed so as to obviate the tendency of conventional plugs to break connections due to a twist of the cable.

A further object of the invention is to provide a method of attaching the retaining nut to the plug body in a non-separable manner.

The invention still further includes an improved method of grounding the cable to the plug body.

Other objects and advantages of the invention will be apparent from the following description of one embodiment of the invention and from the drawings, in which:

Fig. 1 is a view, partly in section, of a preferred embodiment of the present invention;

Fig. 2 is an end view of Fig. 1;

Fig. 3 is a plan view of one of the parts of Fig. 1;

Fig. 4 is a side sectional View of Fig. 3;

Fig. 5 is a side view of another of the parts of Fig. 1;

Fig. 6 is a side view, partly in section, of two other parts of Fig. 1.

In Fig. l is shown a partly sectional view of a plug assembly for an electrical cable in accordance with the present invention. A cable A is provided with a pair of spaced conductors I and 8 respectively surrounded by individual insulating coverings 9 and ID, which in turn, may be surrounded by separate metal sheaths 9A and IDA (-Fig. 2). Over these separate sheaths 9A and IDA is a common outer sheath I I which may be formed of copper braid, while an outer insulating covering I2 encloses the sheath II. The entire cable construction is thus of a more or less conventional type, and it is to be understood that the invention is not limited to this or any other particular type of cable.

A tubular body I9 is also shown in Fig. 1 enclosing an extremity of the cable A. A disc I of a suitable insulating material with three prong 22, 23 and 24 in spaced apart relation therein is positioned removably in the body I9. A second insulating disc 20 has three openings therein to receive prongs 22, 23 and 24, and slides over such prongs to set face to face with disc H as shown.

The prongs 22, 23 and 24 are respectively provided with terminals I3, I4 and I5 on the inner face of disc 2I. Terminal I3 is joined by means such as soldering to conductor I of cable A. Terminal I5 is joined to conductor 8. Terminal I4 is joined, preferably by soldering, to the outer sheath I I of cable A by a connecting wire I8.

Partly enclosing the exposed conductors I and B and the connecting wire I8, and adjacent the disc 2I, is an insert retainer sleeve 25 having a cut-out portion 26 in the outer surface thereof to allow for inspection of or access to the connections between the cable conductors and the prong terminals. This cut-out portion may best be seen by referring to Figs. 3 and 4 which show detailed views of the insert retainer sleeve 25.

A central opening 28 (Fig. 4) in retainer sleeve 25 allows for insertion therein of cable A, this opening having a shape corresponding to the cross-sectional shape of cable A. A sloping shoulder 21 is formed on retainer sleeve 25 as shown in Fig. 4.

A ring-shaped sleeve 29 of rubber or other resilient material encircles the cable A and adjoin-s a portion of insert retainer sleeve 25. A sloping section 33 of the outer surface of sleeve 29 is designed for parallel relationship with shoulder 21 of insert retainer sleeve 25 as shown in Fig. 1.

Between the shoulder 21 of insert retainer sleeve 25 and the sloping section 33 of resilient sleeve 29 is positioned a grounding ferrule also shown in Fig. 5. This ferrule comprises a ring-shaped disc 32 of conducting material such as copper and has an inwardly-extending tongue-shaped portion 30 bent at right angles to the plane of disc 32, the tongue 30 thus being substantially parallel to the axis of cable A. The tongue 30 is also designed to lie flat on the surface of cable A, and an opening 3] in tongue 30 permits soldering or other connection of tongue 30 to sheath I I as shown in Fig.

3 1. Since one face of ring-shaped disc 32 constituting the grounding ferrule lies flat against the shoulder 21 of insert retainer sleeve 25, it will be seen that an electrical connection is established between sheath ll of cable A and the insert retainer sleeve 25. Since such sleeve 25 as Well as body [9 is formed of conductive material, it follows that the cable shielding is efiectively grounded to the body of the plug assembly.

A compression sleeve 34 is inserted part way into body l9 so as to contact resilient sleeve 29 as shown in Fig. l. An end view of this compression sleeve may be seen in Fig. 2. Two threaded openings 3i and 38 are formed in an extending portion of body I9, and two openings 39 and 49 are formed in oppositely-disposed portions of compression sleeve 34.

Bolts

35 and 36 are designed for insertion in these openings as shown in Fig. 1.

In assembling the plug, the cover t2 of cable A is cut back to expose the common braided sheath ll. The common sheath H (and the individual conductor sheaths 9A and IDA) are then out back to expose the individual insulating coverings 9 and II], which are in turn partly removed so as to expose the conductors l and 8. Compression sleeve 34 containing

bolts

35 and 36 is slipped over the end of the cable, as is also resilient member 29, grounding ferrule 32, and insert retainer sleeve 25, these parts being properly positioned relative to each other. The insulating disc 2l (with the terminals I3, I4 and 15, as well as the prongs 22, 23 and 24 already securely positioned therein) is then brought up. The cable conductor 1 is soldered to terminal I3, conductor 8 is soldered to terminal [5, and connecting wire i8 is soldered to both terminal I4 and sheath 1 I.

When these connections are completed, insert retainer sleeve 25 is drawn back to partly enclose the connections, followed by the grounding ferrule 32, the resilient member 29, and the compression sleeve 34. The opening 3| in tongue 30 of grounding ferrule 32 now permits the tongue 39 to be soldered through opening 26 to the sheath Insulating disc 20 is now slipped over the .prongs 22, 23 and 24. and the above assembly inserted in body IS. A shoulder 48 on the inner wall of body l9 contacts shoulder 49 on insert in a compression of resilient member 29 between insert retainer sleeve 25 and compression sleeve (The presence of grounding ferrule 32 does not interfere with this operation.) This pressure on resilient member 29 results in a tight union between such member and all points of its enclosure,'rendering the cable end of the plug assembly substantially waterproof. An opening 53 between the resilient member 29 and the inner wall of body i9 allows for distortion of the resilient member due to action of compression sleeve 34.

As hereinbefore explained, the opening or window 25 in retainer sleeve 25 permits ready inspection of or access to the soldered connections.

'Grounding ferrule 32 grounds sheath ll of cable A to body l9 through retainer sleeve 25.

Compression sleeve 34 is provided with an extending portion 4| which extends away from the body l9 of the plug assembly. This extending portion 4! is designed to loosely encircle the cable covering [2, and any twisting or bending of cable A at a point removed from the plug assembly will be transmitted to and resisted by such extending portion 4| rather than the body l9. This design tends to substantially reduce the possibility of breakage or damage to the soldered connections between the conductors of cable A and the plug terminals.

The method of inserting the plug assembly into a receptacle of conventional type will not be discussed here. However, the invention does provide for a novel method of associating the engaging nut 42 with the body l9 in a non-separable manner.

As best shown in Fig. 6, engaging nut 42 has an annular slot 44 on the inner surface thereof. An opening 45 is formed in one side of this slot 44. A retaining ring 46 is split as shown in Fig. 6 and designed to be insertable through opening 45 into slot 44, by the method of placing one end of the ring into the opening and then feeding the ring into the opening until the other end of the ring snaps into place in the slot to remain permanently therein.

The outer surface of bod 59 has a circular ridge 43 shown in Fig. 1. The engaging nut 42 is placed over the end of the body until ridge 43 contacts a shoulder 47 (Fig. 6) on the inner surface of engaging nut 42. (In use, a gasket is placed between ridge 43 and shoulder so as to render this end of the plug assembly waterproof). When the retaining ring 46 is in place in slot 44 it rotatably positions nut 42 on body l9,but prevents a subsequent removal of the nut.

While We have described above the principles of our invention in connection with specific apparatus, and particular modifications thereof, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of our invention asset forth in the objects of our invention and the accompanying claims.

We claim:

1. In a plug assembly for the extremity of an electric cable having one or more conductors, the combination of a tubular body to receive the end of said cable, a disc-shaped insert of insulating material disposed in said tubular body, a plurality of prongs positioned on one face of said disc-shaped insert, each of said prongs having a terminal on the opposite face of said insert, means forming electrical connections within said body between said. terminals, respectively, and the conductors of said cable, an insert retainer sieeve within. said body, adjacent said disc-shaped insert, a ring-shaped resilient 'member within said body, adjacent said retainer sleeve, and around said cable, a compression sleeve partially within said body, adjacent said resilient memher, and around said cable, and tightening means on the exterior of said body and said compression sleeve, whereby operation of said tightening means will tend to compress said'resilient member between said compression sleeve and said retainer sleeve.

2. The plug assembly defined in claim 1, whercin said cable is equipped with. a grounding sheath enclosing said conductors, in combination with a groundin ferrule disposed between said insert retainer sleeve and said ring-shaped resilient member, said ferrule being electrically joined within said retainer sleeve to said sheath so as to ground said sheath to said retainer sleeve.

3. The plug assembly defined in claim 1, wherein said insert retainer sleeve has a cut-out portion permitting access to and inspection of said electrical connections Without alterin the position 01 said retainer sleeve With respect to said cable.

AVERY G. RICHARDSON. MURRAY KAPLAN.

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

UNITED STATES PATENTS Number Name Date 798,078 Simpson 1- Aug. 29, 1905 944,877 Koschinski Dec. 28, 1909 1,345,473 Benjamin July 6, 1920 1,673,644 Shoe June 12, 1928 Number Name Date Edmonds June 10, 1930 Proos Nov. 4, 1930 Borden May 31, 1932 Bondeson Sept. 25, 1934 Tornblom Aug. 22, 1939 Roper Nov. 28, 1939 Finlayson Jan. 6, 1942 Hayes Dec. 8, 1942 Markey Dec. 29, 1942 Markey Oct. 12, 1943 FOREIGN PATENTS Country Date Austria Feb. 25, 1936 Great Britain June 30, 1937 Great Britain July 15, 1941