GB2130816A

GB2130816A - Improvements in gripping or locating devices

Info

Publication number: GB2130816A
Application number: GB08232641A
Authority: GB
Inventors: Derek Hayes
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-11-16
Filing date: 1982-11-16
Publication date: 1984-06-06
Also published as: GB2130816B

Abstract

A jaw device 1 for locating or gripping an elongate member 23a or 23b comprises a channel-shaped member 2 having two spaced-apart, substantially parallel first jaws 3 and 4 joined together by a web 5, and defining between them a gap 6 for the reception of the elongate member. Two further jaws 10, 11 are hinged to opposite sides of the channel-shaped member 2 at or close to the web 5 and have i) respective recesses 16, 17 for the reception of a respective one of the jaws 3, 4 and ii) respective projections 18, 19 which, when the jaws 10, 11 are hinged toward each other, abut outwardly-facing surfaces of the jaws 3, 4. A device used in an electrical coupling may have a slot formed in web 5 for receiving an electrical contact blade which pierces a conductor cable gripped between the jaws. <IMAGE>

Description

SPECIFICATION Improvements in gripping or locating devices This invention relates to a device for gripping or locating an elongate member. In particular, but not exclusively, the invention relates to a device for gripping or locating an electrically insulated cable or conductor in an electrical coupling device. The invention also relates to an electrical coupling device comprising such a locating or gripping device.

In my British Patent Specification No.

1,559,789 (hereinafter referred to as "the aforesaid Specification") there are described various embodiments of electrical coupling devices each comprising a body portion having an electrically-insulating part with a recess in its surface, and electrically-conductive metallic piercing means mounted in said recess and extending generally in the direction of a pair of opposed sides of the recess but laterally spaced therefrom, and conductor-locating means comprising a pair of cooperating jaws movable relative to each other and having mutually confronting surfaces configured to receive between them and locate an insulated electrical conductor when said jaws are urged towards one another, at least one end of said pair of jaws being configured to enter said recess and to allow entry of said piercing means bet- the jaws and piercing of said conductor by said piercing means when said one end of the jaws is advanced into said recess, the outer surfaces of said pair of jaws and said opposed surfaces of said recess being configured to produce a camming action such that advancing said jaws into said recess urges the jaws towards one another to locate said conductor at least during piercing of the conductor by the piercing means.

In the specification of my published British Patent Application No. 2039426A (hereinafter referred to as "the aforesaid Application") there is described an electrical coupling device of the kind comprising a housing, means within the housing for effecting electrical connection to one or more conductors of an electrical cable which enters the housing in use of the device and a cable grip for clamping the cable relative to the housing, which is characterised in that the cable grip comprises a pair of cooperating jaws adapted to receive the cable therebetween and camming means formed in the housing into which the pair of jaws with the cable therebetween can be pressed, said camming means being arranged to exert pressure on a pair of opposed surfaces of the pair of jaws to force the jaws towards one another to grip the cable when the jaws are pressed into the camming means in a direction substantially perpendicular to the path of the cable through the jaws, and said housing comprising means to limit movement of the jaws in the direction of said path when a tensile force is applied to the gripped cable in a direction tending to pull the cable out of the coupling device.

In the coupling devices of both the aforesaid Specification and the aforesaid Application there is a pair of cooperating jaws having for its purpose to locate or grip, respectively, an insulated electrical conductor or cable, respectively, and in use of the coupling devices the problem arises that the pair of jaws may be required to locate or grip a conductor or cable in a range of widely differing sizes, the problem being more pronounced in the case of the cable grip of the coupling device described in the aforesaid Application.

Ways in which this problem can be overcome have been suggested in both the aforesaid Specification and in the aforesaid Application.

Thus, in the aforesaid Specification and in the aforesaid Application it has been proposed to employ a pair of jaws provided with a plurality of conductor- or cable-receiving slots of different sizes, for example as illustrated in Figure 6b of the aforesaid Specification and Figure 4 of the aforesaid Application. Again, in both the aforesaid Specification and the aforesaid Application, it has been proposed to employ a pair of jaws provided with a conductor- or cable-receiving slot of oval cross-section and in the aforesaid Application it has been proposed to provide packing pieces which can be inserted between the jaws of a pair to reduce the space available between the jaws for accommodating the cable.

The disadvantage of providing the user with a choice of ways in which to employ a pair of jaws in the above described coupling devices is that there will always be someone who makes the wrong choice, with the possible result that the jaws will not provide an effective conductor-locating or cable-gripping function.

The problem discussed above also arises in other situations where a device is required to locate or grip one of a number of elongate members having a range of different crosssectional areas, for example gripping one of a number of conduits of different sizes at an entrance to an electrical junction box.

The present invention aims to provide a device for locating or gripping an elongate member which at least partly eliminates the problem discussed above.

According to one aspect of the invention, a jaw device for locating or gripping an elongate member comprises a channel-shaped member having two spaced-apart, substantially parallel first jaws joined together by a web, said first jaws being deflectable toward and away from one another and defining between them a gap for the reception of the elongate member it is desired to locate or grip, and two further jaws hinged to opposite sides, respectively, of said channelshaped member at or close to said web, the hingeing axis of each of said further jaws being substantially parallel to the longitudinal axis of said channel-shaped member, the faces of said further jaws which confront one another when said further jaws are hinged toward each other having a recess for the reception of a respective one of said first jaws when the further jaws are hinged toward each other, and each of said further jaws comprising a projection which, when said jaws are hinged toward each other, abuts an outwardly-facing surface of a respective one of said first jaws.

According to another aspect of the invention, an electrical coupling device comprises at least one jaw device in accordance with the first aspect of the invention which is employed to locate or grip an insulated electrical conductor or cable, respectively, within the coupling device. For example, the jaw device may serve as the cable grip in a multi-pin electric plug. Again, the jaw device may be employed as the conductorlocating means in an electrical coupling device of the kind described in the aforesaid Specification.

In particular, the jaw devices may be employed as conductor-locating means in a 3-pin, 13 amp fused plug of the non-rewirabie kind, in which connection between the insulated conductors of a cable and the pins of the plug is effected by metallic piercing means which penetrate the conductors, for example as described in the aforesaid Specification. In this last mentioned case, the jaw devices may, with advantage, be employed in combination with means for displacing insulation from the conductors.

In each of the above recited aspects of the invention, the jaw device may be moulded in one piece from a synthetic resin material, which may be either a thermoplastics material, for example nylon, or a thermosetting plastics material, for example a phenolic or amine resin.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which Figure 1 is a side view of one embodiment of a jaw device in accordance with the invention, the device being shown in open position, Figure 2 is a plan of the device of Figure 1, Figure 3 is a sectional view taken on the line Ill-Ill of Figure 1, Figure 4 is a sectional view of part of an electrical coupling device employing the jaw device of Figure 1 , the jaw device being shown partly in end view and partly in section and being employed to locate an insulated electrical conductor of small cross-sectional area, and Figure 5 is a view similar to Figure 4, but showing the jaw device employed to locate an insulated electrical conductor of larger crosssectional area.

Figures 1 to 3 show a jaw device, generally designated by the reference numeral 1, which is moulded in one piece from synthetic resin material, for example nylon.

The device 1 comprises a channel-shaped member, generally designated by the numeral 2, which consists of two spaced-apart, substantially parallel jaws 3 and 4 which are joined together by a web 5. The jaws 3 and 4 are deflectable toward and away from each other at theirfree ends and they define between them a gap 6. A rectangular through-slot 7 is formed in the web 5, the longitudinal axis of this slot being parallel to the jaws 3 and 4, and the slot being disposed midway between the front and rear faces 8 and 9, respectively, of the jaw device.

Two further jaws 10 and 11 are connected by thin webs 12 and 13, respectively, to opposite sides, respectively, of the web 5, the webs 12 and 13 serving as hinges, disposed parallel to the jaws 3 and 4, which enable the jaws 10 and 11 to be hinged, relative to the channel-shaped member 2, in the directions indicated by the arrows A. The faces 14 and 15 of the jaws 10 and 1 1 are provided with respective recesses 1 6 and 1 7 which extend from the front face 8 of the jaw device to its rear face 9. Ribs 1 8 and 1 9 project from the floors of the recesses 1 6 and 1 7, respectively, each of these ribs also extending from the face 8 of the jaw device to its face 9.

Shallow grooves 20 and 21 are formed in the faces 1 4 and 1 5, respectively, of the jaws 10 and 1 , the edges of these grooves being disposed parallel to the faces 8 and 9 of the jaw device, and each groove having a width equal to the length of the slot 7 and being disposed midway between the faces 8 and 9. An elongate slot 22 is formed vertically through the jaw device, this slot having its longitudinal axis disposed parallel to, and midway between, the faces 8 and 9. The slot 22 extends through part of the jaw 10, the projection 18, the web 12, the channel-shaped member 2, the web 13, the projection 1 9 and part of the jaw 11.

The jaw device shown in Figures 1 to 3 may be employed to grip or locate an elongate member, for example a rod 23a or 23b of circular crosssection shown in chain lines in Figure 1. To this end, the rod 23a or 23b is first presented to the jaws 3 and 4 with its longitudinal axis parallel to the jaws 3 and 4 and the web 5, with the jaws 10 and 11 hinged away from each other. Depending on the cross-sectional area of the rod, it will either pass between the jaws 3 and 4 and take up a position wholly in the gap 6, such as the position occupied by the rod 23a, or it will rest on the free ends of the jaws 3 and 4, like the rod 23b.The jaws 10 and 11 are then hinged toward each other in the direction of the arrows A until their faces 14 and 15 are close to each other, to enclose the rod 23a or 23b within the jaw device.

In this closed position of the jaws 10 and 1 the free ends of the ribs 1 8 and 1 9 bear against the outwardly-facing surfaces of the jaws 3 and 4, respectively. In the case of the rod 23a, the ribs 18 and 19 will deflect the jaws 3 and 4 slightly towards each other so that the rod is firmly located in the gap 6. In the case of the rod 23b, the free ends of the jaws 3 and 4 will be deflected away from each other as the rod is forced between them by the rod entering the recesses 1 6 and 17, the jaws bending about their points of abutment with the ribs 1 8 and 19, respectively. The rod 23b will then be firmly located partly in the gap 6 and partly in the recesses 1 6 and 17.

However, the jaw device 1 is designed particularly for employment in an electrical coupling device for the purpose of accurately locating an insulated conductor relative to a metallic piercing means which serves to make electrical connection between the electricallyconducting material of the conductor and, for example, a contact pin of the coupling device, in the manner described in the aforesaid Specification. The use of the jaw device 1 for this purpose is illustrated in Figures 4 and 5 of the accompanying drawings. In each of these Figures, the jaw device 1 is shown in section to the left of the line B - B and in end view to the right of this line.

Figure 4 shows the jaw device 1 pressed into a recess 24 in a block 25 of electrically insulating material, the recess 24 having spaced-apart, parallel side walls 26 and 27. A metallic piercing means, in the form of a blade 28, projects into the recess 24 from the base 29 of the latter, the blade 28 being disposed midway between, and parallel to, the side walls 26 and 27. From Figure 4 it will be seen that insertion of the jaw device 1 into the recess 24, with an electrically-insulated electrical conductor 30 positioned in the gap 6, has resulted in the blade 28 passing through the slot 7 in the web 5, piercing the conductor 30 and then passing between the jaws 10 and 11 in the grooves 20 and 21.During this piercing of the conductor 30, the latter is accurately located midway between the side walls 26 and 27 of the recess 24 by the jaws 3 and 4, which are deflected slightly towards one another by the ribs 18 and 19ofthe jaws 10 and 11.

To ensure good electrical contact between the blade 28 and the electrically-conducting material of the conductor 30, an L-shaped insulation displacement plate 31 may be arranged in the recess 24, prior to insertion of the jaw device 1, with its horizontal limb 32 resting on the floor 29 of the recess. The insulation displacement plate 31 may be of the kind shown in Figure 1 5 of British Patent Specification No. 1,389,170. As the jaw device 1 is inserted into the recess 24, the upright limbs 33 and 34 of the plate 31 are received in the slot 22 (see Figures 1 to 3) of the jaw device, and the conductor 30 is forced down into the gap 35 between the limbs 33 and 34, resulting in displacement of insulating material from the conductor 30.

Figure 5 shows the same jaw device 1 and recess 24 used to locate an electrically-insulated conductor 30a during its piercing by the blade 28, the conductor 30a being of larger cross-sectional area than the conductor 30 shown in Figure 4. In this case it will be seen that the conductor 30a has been accommodated in the jaw device 1 by deflection of the free ends of the jaws 3 and 4 away from each other, these jaws having bent around their points of abutment with the ribs 1 8 and 19, respectively. The only other difference between Figures 4 and 5 is that, in the latter, the insulation displacement plate 31 has a wider gap 35 than in Figure 4, in order to accommodate the larger conductor.

The combination of the jaw device 1, the recess 24, the blade 28 and the insulation displacement plate 31 may form part of a non-rewirable, 3-pin 13 amp fused plug. In this case, the recess 24 may take the form of a hole formed in a base member of the plug, or it may be formed between a pair of spaced-apart pillars formed integrally with the base of the plug. To facilitate connection of the conductor 30 (or 30a) to the blade 28, the jaws 10 and 11 may be provided with grooves 36 and 37, respectively, which allow the jaw device to be entered a short distance into the recess 24, with the jaws 10 and 11 separated from one another, prior to presenting the conductor 30 (or 30a) to the jaws 3 and 4.

As previously mentioned, the jaw device in accordance with the invention may be used for locating or gripping elongate members other than insulated conductors or cables in electrical coupling devices. In such other uses of the jaw device, it would not be necessary to provide the slots 7 and 22 in the jaw device shown in Figures 1 to 3. If it is necessary accurately to register the jaws 10 and 11 in relation to one another when these jaws are closed together, a projection 38 may be provided on the face 14 of the jaw 10 which enters a recess 39 in the face 1 5 of the jaw 11.

The invention is not, of course, limited to the particular embodinients of the jaw device described above with reference to the drawings.

For example, the ribs 18 and 1 9 may be positioned differently in the recesses 1 6 and 1 7 so that, when the jaws 10 and 11 are hinged toward each other, the ribs 18 and 19 abut regions of the outwardly-facing surfaces of the jaws 3 and 4, respectively, that are either closer to, or further from, the web 5 than in the case of the jaw device of Figures 1 to 3. In some embodiments of the jaw device, it may even be desired to arrange for the ribs 1 8 and 1 9 to abut the outwardly-facing surfaces of the jaws 3 and 4, respectively, at the free ends of the latter.

Claims

1. A jaw device for locating or gripping an elongate member, said device comprising a channel-shaped member having two spacedapart, substantially parallel first jaws joined together by a web, said first jaws being deflectable toward and away from one another and defining between them a gap for the reception of the elongate member it is desired to locate or grip, and two further jaws hinged to opposite sides, respectively, of said channel-shaped member at or close to said web, the hinging axis of each of said further jaws being substantially parallel to the longitudinal axis of said channel-shaped member, the faces of said further jaws which confront one another when said further jaws are hinged toward each other having a recess for the reception of a respective one of said first jaws when the further jaws are hinged toward each other, and each of said further jaws comprising a projection which, when said jaws are hinged toward each other, abuts an outwardly-facing surface of a respective one of said first jaws.

2. A jaw device according to claim 1, moulded in one piece from a synthetic resin material.

3. Ajaw device constructed and arranged substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 to 3 of the accompanying drawings.

4. An electrical coupling device comprising at least one jaw device according to any of claims 1 to 3 which is employed to locate or grip an insulated conductor or cable, respectively, within the coupling device.

5. An electrical coupling device according to claim 4, in which said at least one jaw device is employed to locate an insulated conductor which, in use of the coupling device, is pierced by a metallic piercing means which is electrically connected to a contact pin of the coupling device.

6. An electrical coupling device according to claim 5, in which said at least one jaw device is received in a recess within the coupling device, said metallic piercing means being mounted in said recess.

7. An electrical coupling device according to claim 6, in which said recess is in the form of a hole in a base member of the coupling device.

8. An electrical coupling device according to claim 6, in which said recess is formed between a pair of spaced-apart pillars formed integrally with a base member of the coupling device.

9. An electrical coupling device according to any of claims 6 to 8, in which an insulation displacement plate is mounted in said recess.

1 0. An electrical coupling device constructed and arranged substantially as hereinbefore described with reference to, and as illustrated in, Figures 4 and 5 of the accompanying drawings.