US 2521822 A
Description (OCR text may contain errors)
Sept. 12, 1950 l. x. BOSWELL 2,521,322
CONNECTOR 0R TERMINAL MEMBER Filed Nov. 18, 1947 2 Sheets-Sheet 2 ated with another termination member.
Patented Sept. 12, 1950 UNITED STATES PATENT OFFICE lifiiiiilif Application November 18, 1947, Serial No. 786,581 In Great Britain November 15,, i946 Section 1, Public Law 690, August 8, 1946 Patent expires November 15, 1966 This invention relates to connectors or termination members for electric cables.
Hereafter the term connector is intended to mean a composite structure of two separable Darts secured one to each of the cable ends which are to be joined while the term termination member is intended to mean the single part of such a connector which is secured to one cable end and which serves to effect physical connection of two cable ends when operatively associ- Such termination member may or may not, in itself, perform any electric current conducting function,
Connectors for electric cables more especially tele-communication cables have hitherto been provided by termination members on the respective cable ends, one of which is a male member and the other a female member. In conveniences of this arrangement are the necessity of providing two types of termination members and the fact that in use, attention has to be given to ensuring that two cables to be joined will have termination members of different kinds. Similar considerations apply in the connection of the end of a cable to a termination member or socket on an apparatus.
One Object of the invention is the. provision of an improved electric cable onnector comprising two tennination members which w ll intercouple with each other while a further object is the provision of a termination member which will intercouple with an exactly similar termination member.
A further object of the invention is to provide a termination member capable of interlockingv with a similar termination member to constitute an electric cable connector and comprising a tubular body structure having inner and outer coaxial semi-cylindrical tubular projections with a limited region at the free end of said outer projection provided with a screw thread, and an internally threaded sleeve coupling loosely carried upon said body structure with an inwardly directed'flange thereon engageable behind a shoulder on said body structure so that the threads of such sleeve coupling can engage with the corresponding threaded region of the outer projection of a similar termination member when placed in mating connection therewith but not with the threads on its own outer projection whereby, upon tightening such sleeve coupling, the, two termination members are forcibly drawn towards each other in an axial direction to set up a tightly iclaims. (drives-32s) to enlarged scale, of one embodiment of the invention as applied to a connector for a two-core electric cable.
Figure 2 is a view similar to Figure 1, but with all of the parts except the sleeve couplings shown in elevation.
Figures 3a, 3b, 3c and 3d constitute, in conn bination, an exploded view of the constituent parts of one termination member of the connector shown in Figures 1 and 2.
Figures 4a. and 4b illustrate a modified form of the parts shown in Figures 3b and 30 respectively, suitable for use with a single core cable or a concentric-type cable. I I
Referring first to Figures 1, 2 and 3a, to 3d, the connector comprises two identical termination members indicated generally at Ia, I 12, each secured to the ends of the electric cables 2 which are to be connected together. 7
Each termination member comprises a generially tubularbody structure consisting of an in.- ternally threaded outer member '24 and an inner member Hi having an externally threaded cylindrical base 32 screwed into such outer member to a transverse slot in said member and held. in engagement with the cable by means of screws tapped into-the body of the member 24.
Within the bore of the inner member I9 is carried aninsulating bushing 4 which is suitably bored axially to receive the electric connection terminals of the cable conductors in a manner described in greater detail later. The end of the member I9 is formed at its forward or free end with 'tWo semi-cylindrical tubular projections 5, 6. These projections are coaxial with the axis of the tubular structure 3 and are disposed so as each to. embrace opposite circumferential regiens. The inside radius of the inner projection 5 is made just greater than the radius of the bushing '4 while the outside radius of such projection is made just less than the inside radius of the outer projection 6 whereby an exactly similar pair of projections on the other termination member may be interfitted therewith.
The outer cylindrical surface of the outer projectionc is provided with an externally project.- ing screw thread 22 over a limited region lying immediately adjacent its free end, the remainder 'of its outer surface lying nearer to the threaded boss 32 being unthreaded and of a radius less than the base dimension of the thread 22.
The end of the outer member 24 lying opposite to that provided with the cable clamping means, is formed with a projecting shoulder 26 while loosely. disposed around this member is an intcrnally threaded sleeve coup g 21 havin a cannot reach as far as the threads 22 on such projection.
Further details of the construction will become apparent from the following description of'the method of assembly and connection, now to be given in conjunction also with Figs. lid-3d. To the end of the cable 2 is attached a circular metal disc or washer ll having two oppositely disposed straight chord surfaces and a ring shaped neck of lesser diameter through which the central portion of the cable is passed. Any braiding on the cable can be soldered to the ring. The top layer of insulation or cording can be bound off below the ring. The cable is assumed to contain a single pair of conductors and the respective conductors are passed through openings in an insulating disc I2 flattened over two oppositely disposed portions corresponding to the similar surfaces on the metal disc H. A raised collar l3 of insulating material is formed where the two conductors emerge from the disc i order to increase the leakage path between the conductors. The conductors are terminated by inner connecting members each provided with a metal collar l'5 comprising respectively a silver plated rod 14 and a slightly longer hollow cylindrical pin it adapted to receive a rod of the sam'esize as l4, and provided with longitudinal slots to give a spring effect to grip such a rod. The cable end thus prepared is next inserted into the insulating bushing 4 which as shown in Figures 1 and 3b is in the form of a cylinder with two borings to receive the members l4 and I6 and the collars IS. A small projection I1 is provided for a purpose to be described later. At the lower or cable mounting end the bushing 4 terminates in a disc shaped portion [8 of the same flattened shape as the discs H and I2, and at the other end the block is stepped by cutting away a semi-circular segment of the material thereof over the boring for the pin I4. The purpose of this is to assist in forming a firm connection with the cooperating terminal and also to increase the leakage path between the two exposed electric connectionterminals l4 and lBat this point.
The prepared cable end in the bushing 4 is next inserted into the inner member l9 shown in Figs. 1, 2, and 3a. The projection ll of the bushing 4 fits into a recess 20 in this member I9 to ensure that the bushing is inserted the correct way round. Extension limbs 2| on the member [9 are provided to overlay the flattened portions on the discs I I, I2 and I 8 and so prevent rotation of these parts with respect to one another.
Fitting over the cable 2 and screwing over the thread 23 of the member l9 there is provided the internally threaded outer member 24 shown in Fig. 6d.
A variation of the terminal arrangements shown in Figs. 3b and 3c is shown in Figs. 4a and 4b, to be used for single cored cable for example a coaxial cable. Only a single aperture is provided in the disc 12. A central silver plated rod or cylindrical conductor 28 terminates the cable conductor. The base of the rod is formed by a ring 29 of a slightly greater diameter than the rod itself, flattened at one side. In the top of the rod is cut a V-shaped slot into which is fitted a flat silver plated tongue 30 so that it lies substantially along the axis of the rod, and a curved springy silver plated tongue 3| which touches or almost touches the first tongue towards its tip.
The bushing shown in Fig. 7a is internally bored to receive the shape of the rod 28 which will be prevented from rotation with respect to the bushing due to the shape of the ring 29 and its recess in the bushing.
The completely assembled connector is shown in Figures 1 and 2. The sleeve coupling 21 of one termination member screws on to the threaded portion 22 on the outer projection 6 of the other termination member while the sleeve coupling 21 of such second termination member similarly screws over the threaded portion 22 of the outer projection 6 of the first termination member. When the sleeves 21 are each tightly screwed up the cable end of the sleeve comes to bear tightly against the shoulder 26 on the member 24 and the threaded portion 22 of the other terminal is thereby drawn axially inwards towards the shoulder so that the semi-cylindrical shell segments or projections 5, 6 of the two termination members interlock.
At the same time as the interlocking of the inner and outer semi-cylindrical projections is being effected, the inner electric conductor terminal or terminals will be firmly interengagedf In the case of a terminal according to Figs. 3b'and 3c the rod l4 of one terminal will be forced into the hollow cylindrical pin I6 of the other terminal and the rod I4 of the second terminal into the hollow cylindrical pin I 6 of the first. The stepped portions of the bushings shown in Fig. 3b will also interflt.
In the case of the variation shown in Figs. 4a and 4b the flat tongue 30 of one terminal will be held between the flat tongue 30 and the curved spring'tongue 3| of the other terminal and vice versa.
A secure and effective connector is thus obtained which can easily be taken apart again by simply unscrewing the sleeve couplings 21 and pulling the termination members apart. It is not possible to unscrew in error some portion of the termination member instead of the sleeve coupling which is an advantage with a connector of this type. The only other unscrewable portion is the member 24 and this will be locked so long as the sleeves 21 are tightly screwed up.
The sleeves 2! and the member 24 are conveniently knurled to facilitate assembly and disassembly.
1. A connector for electric cables of the type comprising two similar interlocking termination members, each termination member comprising a cylindrical insulating bushing having two borings therein to receive the individual conductors of a two conductor cable. one of said conductors having a hollow cylindrical pin extending beyond the end of the other of said conductors, said-bushing having an end portion thereof cut away leaving a semi-cylindrical segment, an inner member surrounding said bushing and having an externally threaded cylindrical base portion and two semi-cylindrical tubular projections, the outside radius of one projection being just less than the inside radius of the other projection. said other projection having an external cylindrical surface which is unthreaded except for a region around the free end thereof, an internally threadedcylindrical outer member in threaded engagement with the threads on the base portion of said inner member, said outer member havin a shoulder at the 2 end thereof, and an internally threaded sleeve coupling on said outer member engage able with said shoulder and extending beyond the end of said outer member so as to surround the unthreaded but not the threaded region of said 1 other tubular projection on said inner member of the termination member and engageable only with the corresponding threaded region or the corresponding tubular projection of the other termination member.
2. A connector for electric cables of the type comprising two similar interlocking termination members, each termination member comprising an element having two parallel conductors extending therefrom, one of said conductors having a female extension for engagement with the male extension of the mating assembly, a cylindrical insulating bushing having two borings therein to receive the parallel conductors, said bushing having an end portion thereof cut away leaving a semi-cylindrical segment which is engageable Q with the cut away portion of the mating bushing of the other assembly, an inner member surrounding said bushing and having an externally threaded base portion and inner and outer opposing semi-cylindrical tubular projections, the
first termination member lying outside the inner projection of said other termination member and forming a cylinder with said outer projection of said other termination member when said two termination members are mated, said outer projection of each of said termination members having an external cylindrical surface which is unthreaded except for a region near to the free ends thereof, an internally threaded cylindrical outer member in threaded engagement with the threads on the base portion of said inner member, said outer member having a flange at one end thereof, and an internally threaded sleeve couplin on said outer member engageable with said flange, and extending beyond the end of said outer member so as to surround the unthreaded but not the threaded region of the outer tubular projection on said inner member of the termination member, said threaded coupling of one termination member being engageable only with the threaded region of the outer tubular projection F directed semi-cylindrical tubular projections, the outside radius of one projection being just less than the inside radius of the other projection, said other projection having an external cylindrical surface which is unthreaded except for a region near to the free end thereof, an internally threaded cylindrical outer member in threaded engagement with the threads on the base portion of said inner member, said outer member having a shoulder at the end thereof receiving said inner member and an internally threaded sleeve coupling on said outer member and provided with an inwardly directed flange engageable with said shoulder and extending beyond the end of said outer member so as to surround the unthreaded but not the threaded region of the tubular projection on said inner member and engageable only with the corresponding thread-ed region of the corresponding tubular projection of the other termination member.
4. A termination member for an electric cable connector of the type comprising two similar interlocking termination members and which includes a tubular body structure having cable gripping means at one end and inner and outer oppositely disposed coaxial semi-cylindrical tubular projections at the other end, the outside radius of said inner projection being just less than the inside radius of said outer projection, said outer projection having an external surface which is unthreaded except for a limited region near to the free end thereof, a shoulder around said body structure intermediate said projections and said end having cable gripping means, an insulating bushing within the bore of said body structure, electric terminal means in said bushing and facing the free ends of said projections and an internally threaded sleeve coupling loosely surrounding said body structure, said sleeve coupling being provided with an inwardly directed flange engageable behind said shoulder to position its internal threads surrounding the unthreaded but not the threaded region of said outer projection so as to be engageable with the corresponding threaded region at the free end of the outer projection of a similar termination member to draw the latter axially into tightly clamped engagement.
IAN IRVINE BOSWELL.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 599,434 Wilson Feb, 22, 1898 904,522 Firmin Nov, 24, 1908 1,975,244 Wiseman Oct. 2, 1934 2,124,207 Neeson July 9, 1938 2,125,816 Reynolds Aug. 2, 1938 2,183,651 Langston et al Dec. 19, 1939 2,286,952 Cannon et al June 6, 1942 2,386,177 Andersen Oct. 9, 1945