Cord grip arrangement

Abstract: A cord grip arrangement for relieving mechanical strain on cord conductors (15,16) of an electrical connector assembly comprising a first shell member (19) and a second shell member (26). The cord grip arrangement comprises a base member (1) from which two limbs (4, 5) extend to form a hinged jaw. One limb is provided with an inwardly extending protuberance (7) which co-operates with a space (8) defined by two shoulders (9, 10) in the other limb when the jaws are held closed over cable 14 by being restrained within second shell member (26) of an assembled electrical connector assembly. Such an arrangement ensures that both the outer sheath and the terminated inner conductors of the cord are securely gripped.

Description: This invention relates to a cord grip arrangement for relieving mechanical strain on cord conductors connected to contact elements of two-part coupling connectors for diconnectably interconnecting the conductors of cords such as audio cables, or disconnectably connecting the conductors of audio cables to appliances. A cord in the present context is defined a any small flexible cable having at least one conductor. Cord grip arrangements are known. One such known arrangement sometimes used in the aforementioned electrical connectors is a collet arrangement which grippingly encircles the cord end. A disadvantage of the known collet grip is that although the cord's outer sheath is securely held when under tension, the cord's inner shield and conductors are strained and tension is transferred to contact elements to which they are connected. An example of such a collet is disclosed in the specification of British Patent No. GB-A-1378817 which describes a connector assembly having a radial cable clamping element in the form of an annular collar having four fingers extending therefrom which exert radical pressure about the cable when the connector is assembled. Another example of a cord grip arrangement is disclosed in the specification of British Patent No. GB-A-2068176 which describes a wire clamping arrangement for clamping a pair of relatively small diameter wires between two separate parts having complementary lands and a recess. This arrangement severely deforms the wires when the parts are clamped together which makes it unsuitable for clamping relatively large diameter and stiffen cables, such as shielded audio cables and the like. It is an object of the present invention to provide an improved grip arrangement which avoids the aforementioned disadvantages. According to the invention there is provided an electrical connector having a first shell member engageable with a second shell member to operatively retain a cord grip device, the first and second shell members including mutual engagement means on respective mating ends of said shell members whereby the first and second shell members may be mated together, the second shell member including a cord entrance passage through which a cord may pass; a cord grip member being adapted to be operatively retained within the mated first and second shell members, the cord grip member including a base member from which a first and a second elongate limb project to form a pair of jaws, at least one of said limbs being hingedly mounted on the base member, the first and second limbs being spaced apart to permit passage of the cord there between, the fist limb including at least one transverse projection extending towards the second limb, the second limb including a recess located substantially opposite the transverse projection, the ends of the limbs remote from the base member and at least part of the interior surface of the second shell member being profiled to co-operate such as to cause the limbs to move together when the first and second shell members are being mated with the cord grip member inside the first and second shell members, whereby the cord is wedged by the transverse projection and the recess. According to a further aspect of the invention, there is provided an electrical connector assembly including the aforementioned and grip arrangement, said assembly including wedge-shaped, and wherein the edge of the projection lies in a plane substantially normal to the longitudinal axis of said one of the two said limbs. In order that the invention may be readily carried into effect embodiments thereof will now be described in relation to the drawings, in which: Figure 1 shows a first perspective of a first embodiment of the cord grip of the present invention. Figure 2 shows another perspective of the cord grip of Figure 1. Figure 3 shows a side view of the cord grip of Figures 1 and 2 in an open position prior to clamping a cord. Figure 4 shows the cord grip of Figure 3 in a closed mode. Figure 5 is a cut-away perspective view of a coupling connector element incorporating the cord grip shown in Figure 1 to 4. Figure 6 shows side view of a second embodiment of the cord grip of the present invention. Figures 7 and 8 show an end view of the base member of the embodiment shown in Figure 6. Figure 9 shows a cut-away perspective view of an insulation-penetrating coupling connector element incorporating the cord grip shown in Figures 6-8. Referring to Figures 1 to 4, the cord grip comprises a base member 1 in the form of an annulus of thermo plastic material having key 2 formed on its outer surface for co-operating with a keyway. Extending from the rear surface of base member 1 are two limbs 4 and 5 forming a pair of jaws, one of which, limb 4, being hinged by a narrow section 6; although it will be understood that both limbs may be hinged in this manner. Limb 4 is provided with an inwardly extending transverse wedge 7 whose axis is substantially normal to the longitudinal axis of limb 4. Limb 5 is provided with a transverse channel section 8 opposite the thin edge of the wedge. The two sides of channel section 8 terminate in respective shoulders 9 and 10; shoulder 10 sloping rearwardly. Limbs 4 and 5 each terminate in a section 11, 12 extending inwardly toward each other at an obtuse angle. A flat shroud 13 extends normal from one side of limb 5. The annulus of base member 1 may be discontinued by a slit. The basic operation of the cord grip will now be described with reference to Figures 3 and 4. An end of cord 14 is fed through base member 1 and insulated conductors 15 and 16 exposed. Closing the jaws causes the section of cord 14 traversing channel 8 to be bent and pinched between the thin edge of wedge 7 and shoulders 9 and 10 thereby providing a secure grip on cord 14 and conductors 15 and 16 and relieving strain in both axial directions. Referring to Figure 5, the jaws described above are operatively arranged in a coupling connector element 17 comprising a body of circular cross-section 18 including a shell portion 19 and an insert 20, the latter being constructed of a hard plastics material or a resilient material such as, for example, rubber. An array of male contact elements 21, 22 and 23 extend outwardly from the insert 20 and are fixedly supported therein. Female contact elements are also envisaged. The rear portion of each contact element protrude rearwardly through insert 20 into a space defined by the rear part of shell portion 19. Attached to the rear portion of each contact element is a rearwardly extending solderable contact, one of which, 24 is shown. Shell portion 19 is provided with a screw thread portion 25 on the outer surface of its rear end. Connector element 17 further comprises a cylindrical outer shell 26 having a rear section in the shape of a conical frustrum through which cable 14 enters. A resilient grommet 27 is fitted to the end of the rear section. In use, the end of cord 14 is fed through grommet 27 and a predetermined length of sheath is removed from the end of cord 14 to expose lengths of insulated conductors 15 and 16. Bared ends of conductors 15 and 16 are terminated on respective solderable contacts 24. The jaws are closed slightly and outer shell 26 is pushed over the slightly closed jaws; base member 1 is aligned using key 2 and inserted into the space in the rear part of shell portion 19, and outer shell 26 is screwed onto shell portion 19. The axial movement of outer shell 26 causes the inner surface thereof to slidably abut sections 11 and 12 of the limbs, thereby fixing the jaws closed and gripping cord 14. The embodiment shown in Figures 6, 7 and 8 is similar to the one described above except that the base member 1 is adapted to be used in a coupling connector having insulation-penetrating contact elements. In this embodiment base member 1 is a cylindrical-shaped solid whose outer surface is provided with an axial first channel 28 for laying the insulated conductors therein so that they can pass from one side of the base member 1 to the other but remain within the boundary of the base member. Referring to Figure 7 the front surface 29 of base member 1 is provided with three radial second channels 30, 31 and 32, each communicating with the first channel 28. Transverse each second channel is a scabbard 33, 34 and 35 for receiving insulation piecing contact elements. Preferably, base member 1 of the embodiment includes a third channel 36 (Figure 8) for receiving therein shielding braid (not shown) which may be incorporated in cord 14 to shield insulated conductors 16 and 17. In order to avoid "hum loops" in some applications it is necessary to ensure that this shielding braid does not contact a metallic connector shell associated with the cord grip. Therefore according to the embodiment shown in Figure 8, a cowling 37 is hingedly attached to the surface of base member 1. The said cowling 37 includes a resilient latch hook 38 which latches onto a shoulder 39. When the cowling is closed over channel 36 the twisted shielding braid is insulated from the inner wall of the metallic connector shell when the base member nests within the connector shell. Figure 9 shows the lastmentioned embodiment operatively arranged in a coupling connector element similar to that described in relation to Figure 5, except that that attached to the rear portion of each contact element is a rearwardly extending insulation-penetrating slotted plate one of which 24 is shown. In use, and referring to Figures 6, 7 and 9, the end of cord 14 is fed through grommet 27 and a predetermined length of sheath is removed from the end of cord 14 to expose lengths of insulated conductors 15, 16 and 16a which are laid in first channel 28 and then respectively laid in second channels 30, 31 and 32 where they are trimmed. The jaws are closed slightly and outer 26 is pushed over the slightly closed jaws; base member 1 is aligned using key 2 and inserted into the space in the rear part of shell portion 19; the insulation-penetrating slotted plates 24 enter the respective scabbards in the base member and penetrate the insulation of insulated conductors 15, 16 and 16a, establishing electrical contact between the conductors and the contact elements. Outer shell 26 is screwed onto shell portion 19 fixing the jaws closed as described in relation to Figure 5. It will be understood that a grub screw arrangement or a tab arrangement could substitute the preferred screw thread arrangement on the connector shells.

Claims: In an electrical connector (17) having a first shell member (19) engageable with a second shell member (26) to operatively retain a cord grip device, the first and second shell members including mutual engagement means on respective mating ends of said shell members whereby the first and second shell members may be mated together, the second shell member including a cord entrance passage through which a cord (14) may pass; a cord grip member being adapted to be operatively retained within the mated first and second shell members, characterized in that the cord grip member includes a base member (1) from which a first and a second elongate limb (4, 5) project to form a pair of jaws, at least one of said limbs being hingedly mounted on the base member, the first and second limbs being spaced apart to permit passage of the cord there between, the first limb including at least one transverse projection (7) extending towards the second limb (5), the second limb including a recess (8) located substantially opposite the transverse projection, the ends (11, 12) of the limbs remote from the base member and at least part of the interior surface of the second shell member being profiled to co-operate such as to cause the limbs to move together when the first and second shell members are being mated with the cord grip member inside the first and second shell members, whereby the cord is wedged by the transverse projection and the recess. An arrangement as claimed in claim 1, wherein the hinged mounting is achieved by a flexible section (6) of said limb. An arrangement as claimed in claim 1, wherein said recess comprises a space defined by two raised shoulders (9, 10). An arrangement as claimed in claim 1, wherein the remote ends of the limbs and the said part of the interior surface of the second shell member form cooperating complementary camming surfaces (11, 12) whereby the cord grip member is pushed into the first shell member (19) and the limbs are moved closer together as the second shell member (26) is mated with the first shell member. An arrangement as claimed in claim 4, wherein a section of each limb proximate their free end is tapered towards the free end of the limb. An arrangement as claimed claim 5, wherein said second shell is a cylinder having a rear section in the shape of a conical frustum whose narrow end forms the cord entrance passage. An arrangement as claimed in claim 1, wherein a section of each limb proximate its free end is tapered towards the free end of the limb. An electrical connector element assembly (17) including a cord grip arrangement as claimed in claim 1, the assembly including at least one forwardly extending contact element (21, 22, 23) whose opposite end terminates in a rearwardly extending termination (24) means in the first shell member (19), the second shell member (26) being detachably attached to said first shell member, at least one limb being hinged by hinge means (6), and wherein the recess (8) is defined by two raised shoulders (9, 10) that extend inwardly from the second limb (26), whereby when an end section of a cord (14) having at least one protruding insulated conductor (15, 16) for termination on said termination means (24) of a detached first shell member (19) is brought through said cord entrance and laid longitudinally between said limbs (4, 5) of said cord grip arrangement with said conductor/s (15, 16) extending towards said base member (1), a part of said end section of the cord spans said recess (8) such that upon holding the jaws (4, 5) closed with a co-operating part within said second shell member (26) of an assembled said connector element assembly, said part of said end section of the cord is wedged between said shoulders (9, 10) and said protuberance (7), wherein said base member is a solid having a rear surface from which said elongate limbs extend, a side surface and a front surface, said side surface including at least one axial first channel (28) for receiving therein said at least one insulated conductor (15, 16), wherein said front surface (29) includes at least one second channel (30, 31, 32) which communicates with said first channel (28), said at least one second channel traverses a scabbard means (33, 34, 35) in said front surface, said scabbard means being arranged for receiving said insulation penetrating means (24). An assembly as claimed in claim 8, wherein said projection (7) is wedge-shaped, and wherein the edge of the projection lies in a plane substantially normal to the longitudinal axis of said one of the two said limbs (4, 5). An assembly as claimed in claim 8, wherein said at least one contact element comprises solderable terminal means. An assembly as claimed in claim 8, wherein said at least one contact element comprises an insulation-penetrating means. An assembly as claimed in claim 11, wherein a third channel (36) is provided in said side surface said third channel communicating with at least one second channel (30, 31, 32). An assembly as claimed in claim 12, wherein said side surface is provided with a hinged cowling member (37) hingedly covering said third channel (36). An arrangement as claimed in claim 13, wherein said cowling member includes clasp means (38) for clasping said cowling member when closed over said third channel (36). An assembly as claimed in claim 14, wherein said base member is substantially cylindrical. An assembly as claimed in claim 15, wherein said first channel's (28) bottom surface is proximate said base member's axis, one second channel (33, 34, 35) radiating therefrom. An assembly as claimed in claim 8, wherein said side surface of said base member (1) includes an axial keyway (2). An assembly as claimed in claim 8, wherein a flat shroud (13) extends from one side of a limb (5), said shroud lying in a plane parallel to a plane intersecting both limbs. An assembly as claimed in claim 8, wherein said base member is an openended wall about a central axis defining a space through which said at least one insulated conductor can pass. An assembly as claimed in claim 19, wherein said base member is an annulus. An assembly as claimed in claim 20, wherein said annulus is discontinued by a slit. An arrangement as claimed in claim 8, wherein the remote ends of the limbs (4, 5) and the said part of the interior surface of the second shell member form cooperating complementary camming surfaces (11, 12) whereby the cord grip member is pushed into the first shell member (19) and the limbs are moved closer together as the second shell member (26) is mated with the first shell member. An assembly as claimed in claim 22, wherein a section of each limb proximate its free end is tapered towards the free end of the limb. An assembly as claimed claim 22, wherein said second shell is a cylinder having a rear section in the shape of a conical frustum whose narrow end forms the cord entrance passage. An assembly as claimed in claim 24, wherein said cord entrance passage is provided with a resilient grommet (27). An assembly as claimed in any one of claims 8 to 25, wherein the first and second shell members include mating threaded cylindrical portions (25), and the remote ends of the limbs and the said part of the interior surface of the second shell member form complementary camming surfaces whereby the cord grip member is pushed into the first shell member and the limbs are moved closer together to wedge the cord as the second shell member is mated with the first shell member.

Inventors: VAN EMMERIK DAVID LAWRENCE, WEISS CHRISTOPHER JOHN, VAN EMMERIK, DAVID LAWRENCE, WEISS, CHRISTOPHER JOHN
Applicants: ALCATEL COMPONENTS LTD, ALCATEL COMPONENTS LIMITED
Application year: 1993
Main classification: H01R13
IPC codes: H05K7, H01R13