GB2071927A

GB2071927A - Improvements in or relating to retaining means for elongate members

Info

Publication number: GB2071927A
Application number: GB8008731A
Authority: GB
Original assignee: Plessey Co Ltd
Current assignee: Plessey Co Ltd
Priority date: 1980-03-14
Filing date: 1980-03-14
Publication date: 1981-09-23
Also published as: GB2071927B

Abstract

Retaining means for retaining elongate members, such as electrical conductors, comprises a conical member 10 having a tapering bore and a locating base 12 at the larger diameter end of the conical member. The conical member is provided with or adapted to be provided with at least two slits which extend axially along the length of the conical member so as to divide the conical member into at least two limbs. The member is formed of a resilient material such that the limbs are resi- lient. When an elongate member having a diameter substantially the same as the bore at the larger end of the conical member is inserted through the conical member, the limbs are deflected outwardly and hence grip the elongate member. <IMAGE>

Description

SPECIFICATION Improvements in or relating to retaining means for elongate members This invention relates to retaining means for elongate members and more particularly, but not exclusively to retaining means for electrical conductors mounted inside an electrical connector.

With electrical components becoming smaller and smaller the connections thereto must also become smaller so that the whole electrical component can be extremely compact. Electrical connectors of the cylindrical type are therefore now being produced containing a plurality of male and female electrical conductors which can be less than one inch in diameter and contain as many as 60 to 70 individual electrical conductors.

It will be appreciated that locating and retaining such a number of conductors in an insulating relationship to each other is a substantial probiem.

Various solutions have been attempted such as providing the conductors which are usually elongate metallic rods with tongs which abut shoulders inside moulded holes through the connectors. These suffer from various disadvantages such as difficulties in removing the conductors and the disadvantage that these can usually only be inserted and removed from one direction only. Furthermore, the conductor is more difficult and more expensive to make than a simple rod without tongs or other retaining means formed thereon.

It is the object of the present invention therefore to provide retaining means for elongate members which will enable a large number of small elongate members to be retained within a small area, the elongate members not needing to be specially shaped to be retained thereby.

According to the present invention means for retaining elongate members comprises a conical member having a tapering bore, a locating base portion arranged at the larger diameter end of the conical member, the conical member being adapted to be provided with at least two slits extending axially over the full length of the conical member so as to divide the conical member into at least two limbs and the material of the conical member being resilient whereby the limbs are resilient such that an elongate member having a diameter substantially the same as the bore at the larger end of the conical member, when inserted through the conical member, deflects the limbs outwardly, the limbs thereafter gripping the elongate member.

The slits may be formed during the manufacture of the conical member, or alternatively may be formed by the insertion of an elongate member to split the conical member, grooves or similar markings being formed in the surface of the conical member so that the slits are formed in predetermined positions.

Preferably the conical member is formed integrally with the base portion and preferably the conical member and the base portion are moulded in a plastics material of good electrical insulating properties.

The ratio of the length of the conical member to the diameter of the bore at its larger end is preferably in a range of substantially 2.5:1 to 4:1.

Preferably the ratio is substantially 2.5:1. Preferably the conical member is adapted to be provided with four symmetrically arranged slits.

Preferably the conical member is formed having four symmetrically arranged V-grooves in its outer surface, each V-groove extending through the majority of the thickness of the wall of the conical member whereby the insertion of an elongate member having substantially the same diameter as the bore at the larger end of the conical member causes the wall to split along the bases of the v-grooves.

Preferably a plurality of conical members are formed on a single base portion.

The invention also comprises a connector having retaining means for elongate members as described hereinbefore.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure lisa cross-sectional view through retaining means for elongate members according to the invention, Figure 2 is an end view of the complete retaining means as seen from arrow 2 in Figure 1, Figure 3 is an end view of retaining means for a plurality of elongate members and Figure 4 is a cross sectional view of the retaining means along the line 4-4 in Figure 3.

As shown in Figure 1 the retaining means comprises a conical sleeve 10 which is formed integrally with a base member 12 from a plastics material. Four v-grooves 14 are formed along the length of the conical sleeve 12 which extend almost through the thickness of the sleeve to leave a thin length 16 of plastics material at the base of each v-groove 14. The four grooves are arranged symmetrically around the outer surface of the sleeve 90 apart, although two, three or more than four grooves could be provided depending on the size of the sleeve, the strength of the sleeve and what is required to be retained by the sleeve.

The bore of the sleeve tapers to give a constant wall thickness and also passes through the base member 12 with a constant diameter. The ratio of the length 20 of the sleeve to the diameter of the bore at its larger end 18 is substantially 2.5:1 although this can be varied up to 4:1 whilst still being capable of being readily moulded by injecting moulding techniques.

When a rod of substantially the same diameter as the bore 18 is passed through the base member 12 and forced into the tapering bore in the sleeve 10, the sleeve being held in position by the base member 12, the sleeve eventually splits along the thin lengths 16 of plastic material to producfour separate limbs. These limbs are flexible and are urged outwards by further insertion of the rod until the rod passes completely through the sleeve. The four limbs then grip the rod at any predetermined position. The rod may be removed from the sleeve in either direction although a suitable stop such as a flange may be provided on the rod so that it can only be inserted and removed from the sleeve from the base member end.Alternatively, the rod may be provided with a length of smaller diameter into which the four limbs can locate, thus only permitting the rod to be removed from the smaller end of the sleeve 10. Various combinations of lengths of smaller diameter and flanges of larger diameter will permit the rod to be inserted into and removed from the cone in various directions.

The sleeve 10 is of true conical form which optimises columnar strength and permits the use of relatively long limbs so that bending stresses are reduced.

Instead of producing the limbs by the splitting method described above, slits may be formed in the sleeve during manufacture, although the moulding technique for this is rather more difficult than the former method.

The retaining means is primarily intended to retain a large number of electrical conductors in a cylindrical connector and an example of such a retaining means is shown in Figures 3 and 4 on a very much enlarged scale. In this case a circular base member 30 is formed with 68 conical sleeves 32 each being made and intended to be split into four limbs as in Figures 1 and 2. The actual overall diameter of the base is less than 2.5 cm and one is intended to be secured by its base member 30 inside each half of a two-part electrical connector. Into each or a number of the sleeves in one half of the connector are inserted male electrical conductors consisting of, for example, copper rods, and into each or a similar number of the sleeves in the other half of the connector are inserted female conductors consisting of sleeves of for example, copper.The diameters of the conductors may vary along their length so that they can only be inserted or removed in a certain direction as mentioned previously.

The retaining means thus provides a simple and effective method of retaining large numbers of very small diameter conductors and also provides sufficient insulation between the conductors. By suitably shaping the conductors and the conical sleeves a choice can be made on which direction each individual conductor can be removed and/or replaced.

Thus, for example, when it is desired that the elongate member is to be reieased from the smaller diameter end of the sleeve lOan extra bell-shaped portion 34 (shown in broken lines in Figure 1) can be formed on the end of the sleeve 10. The bell-shaped portion 34 is also provided with V-shaped grooves 14 so that is splits into the same number of parts as the sleeve 10. The bell-shaped portion 34 acts as a stop for a flange formed on the conductor which is adapted to bear on the end of the sleeve 10 and thus ease the loading on the smaller diameter end.

Claims

1. Means for retaining elongate members com prising a conical member having a tapering bore, a locating base portion arranged at the larger diameter end of the conical member, the conical member being adapted to be provided with at least two slits extending axially over the full length of the conical member so as to divide the conical member into at least two limbs and the material of the conical member being resilient whereby the limbs are resilient such that an elongate member having a diameter substantially the same as the bore at the larger end of the conical member when inserted through the conical member, deflects the limbs outwardly, the limbs thereafter gripping the elongate member.

2. Means as claimed in claim 1 in which the slits are formed during the manufacture of the conical member.

3. Means as claimed in claim 1 in which the slits are formed by the insertion of an elongate member to split the conical member, grooves or similar markings being formed in the surface of the conical member so that the slits are formed in predetermined positions.

4. Means as claimed in any preceding claim in which the conical member is formed integrally with the base portion.

5. Means as claimed in any preceding claim in which the conical member and the base portion are moulded in a plastics material;

6. Means as claimed in any preceding claim in which the ratio of the length of the conical member to the diameter of the bore at its larger end is in a range of substantially 2.5:1 to 4:1.

7. Means as claimed in claim 6 in which the ratio is substantially 2.5:1.

8. Means as claimed in any preceding claim in which the conical member is adapted to be provided with four symmetrically arranged slits.

9. Means as claimed in claim 8 in which the conical member is formed having four symmetrically arranged V-grooves in its outer surface, each v-groove extending through the majority of the thickness of the wall of the conical member whereby the insertion of an elongate member having substantially the same diameter as the bore at the larger end of the conical member causes the wall to split along the bases of the v-grooves.

10. A connector having retaining means for elongate members as claimed in any preceding claim.

11. Retaining means for elongate members constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.