Cord Grip Arrangement

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 disconnectably 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 as 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.

It is an object of the present invention to provide a grip arrangement which avoids the aforementioned disadvantage.

According to the invention there is provided a cord grip arrangement for an electrical connector element assembly of a first shell member supporting therein at least one forwardly extending contact element whose opposite end terminates in a rearwardly extending termination means, and a second shell member having a cord entrance passage, and detachably attached to the first shell member, the cord grip arrangement comprising a base member having two longitudinal limbs extending therefrom to form a pair of jaws, at least one limb being hinged by hinge means, and wherein one of the two of the limbs is provided intermediate its length with an inwardly extending protuberance opposite a space defined by two raised shoulders that extend inwardly from the other the limb, whereby when an end section of a cord having at least one exposed conductor for termination on the termination means of a detached first shell member is brought through the cord entrance and laid longitudinally between the limbs of the cord grip arrangement with the conductor/s extending towards the base member, a part of the end section of the cord spans the space such that upon holding the jaws closed with a co-operating part within said second shell member of an assembled said connector element assembly, the part of the end section of the cord is wedged between the shoulders and the protuberance.

In order that the invention may be readily carried into effect embodiments thereof will now be described in relation to the drawings, in which:

FIG. 1 shows a first perspective of a first embodiment of the cord grip of the present invention.

FIG. 2 shows another perspective of the cord grip of FIG. 1.

FIG. 3 shows a side view of the cord grip of FIGS. 1 and 2 in an open position prior to clamping a cord.

FIG. 4 shows the cord grip of FIG. 3 in a closed mode.

FIG. 5 is a cut-away perspective view of a coupling connector element incorporating the cord grip shown in FIGS. 1 to 4.

FIG. 6 shows side view of a second embodiment of the cord grip of the present invention.

FIGS. 7 and 8 show an end view of the base member of the embodiment shown in FIG. 6.

FIG. 9 shows a cut-away perspective view of an insulation-penetrating coupling connector element incorporating the cord grip shown in FIGS. 6-8.

Referring to FIGS. 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 I may be discontinued by a slit.

The basic operation of the cord grip will now be described with reference to FIGS. 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 FIG. 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 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 FIGS. 6, 7 and 8 is similar to the one described above except that the base member I 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 FIG. 7 the front surface 29 of base member 1 is provided with three radial second channels 30, 31 and 32, each communicating with 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 (FIG. 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 FIG. 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.

FIG. 9 shows the lastmentioned embodiment operatively arranged in a coupling connector element similar to that described in relation to FIG. 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 FIGS. 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 FIG. 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.