GB2253529A - Friction-fit of terminal or pressure plate in connector - Google Patents

Abstract

In an insulation piercing connector for effecting electrical connection between an insulated main electric conductor and an insulated supplementary electric conductor, each of the recesses 4 accommodating the contact blades of the connector, and each of the recesses 14 accommodating a pressure plate 24 associated with a clamping bolt 23, has protruding into the recess from its side walls at least two pairs of oppositely disposed ribs 6, 15 which extend downwardly the full depth of and are longitudinally spaced along the recess and between which a contact blade, or a pressure plate, is a force fit. Each of these recesses 4, 14 also has in the bottom wall of the recess at the foot of each rib 6, 15 a well 7, 16 for the collection of any slivers of insulating material that may be spliced from the rib when a contact blade, or pressure plate, is forced into the recess. Risk that a contact blade, or pressure plate, will not be forced fully home in a recess when forced into the recess is substantially reduced. <IMAGE>

Description

2253529 AN IMPROVED ELECTRIC CONDUCTOR CONNECTOR This invention relates to

connectors for effecting electrical connection between a main electric conductor and a supplementary or spur electric conductor. The invention is particularly concerned with connectors of this kind incorporating contact blades for piercing or displacing the insulation of the main and supplementary conductors in order to effect electrical connection therebetween.

One form of electric conductor connector which incorporates such contact blades and which is in common use comprises two separately moulded bodies of electrically insulating material each of which has in one of two opposed major faces of the body a pair of substantially parallel grooves transversely spaced apart for reception of insulated main and supplementary conductors and, extending transversely of said grooves, at least two elongate recesses which are longitudinally spaced apart and in each of which is accommodated a contact blade of electrically conductive metal or metal alloy which has, in each part of the blade traversing a groove, teeth for piercing or displacing the insulation of a conductor. The two bodies, with their grooves cooperating to form two substantially parallel passages, can be urged together around insulated main and supplementary conductors disposed in said passages to cause the teeth of the contact blades to pierce or displace the insulation of the main and supplementary conductors by pressure exerted by at least one clamping 2. bolt extending through the bodies between said passages. With a view to distributing the pressure exerted by the or each clamping bolt over a wide surface area of the co-operating faces of the bodies. at least one of the bodies has in the other of its two opposed major faces at least one recess in which or in each of which is accommodated a pressure plate of metal or metal alloy which has an aperture for passage of the clamping bolt or one of the clamping bolts and which underlies the head of or a nut working on the bolt. For convenience, an electric conductor connector of the aforesaid form will hereinafter be referred to as "an insulation piercing connector of the kind described".

When assembling an insulation piercing connector of the kind described around its main and supplementary conductors there is a risk that the metal pressure plate or one of the metal pressure plates will be dislodged from the recess in which it is housed or will be so displaced that the pressure exerted by the clamping bolt passing therethrough is insufficient to enable the contact blades to impart a satisfactory electrical connection between the main and supplementary conductors. When dismantling an insulation piercing connector of the kind described from around insulated main and supplementary conductors which it is electrically interconnecting, there is a risk that when the two bodies are disengaged from the conductors and separated a metal contact blade will remain embedded in 3. the conductors and will be exposed thereby constituting a dangerous hazard if the main conductor is live.

It is an object of the present invention to provide an improved insulation piercing connector of the kind described in which each of the metal components of the connector is so retained in its associated recess that risk that any metal component of the connector will be displace in or dislodged from the recess in which it is housed during assembly or dismantling of the connector is eliminated or at least substantially reduced.

In the improved insulation piercing connector of the kind described according to the invention, at least one, and preferably each. of the recesses accommodating a metal component of the connector has protruding into the recess from its side walls at least two pairs of oppositely disposed ribs which extend downwardly substantially the full depth of and are longitudinally spaced along the recess and between which said metal component is a force fit and has in the bottom wall of the recess at the foot of each rib a well for the collection of any slivers of insulating material that may be sliced from the rib when said metal component is forced into the recess.

The provision of a well in the bottom wall of a recess at the foot of each rib for the collection of any slivers of insulating material that may be sliced from the rib when a metal component is forced into the recess 4. ensures that there is negligible risk that any such slivers of insulating material will prevent substantially the whole of the lowermost surface of the metal component from bearing against the bottom wall of the recess and the metal component from being forced fully home in the recess.

Preferably, each transversely extending elongate recess accommodating a contact blade has in its bottom wall at least two longitudinally spaced wells each extending across the full width of the recess at the foot of a pair of oppositely disposed ribs. Preferably, also, each pair of oppositely disposed ribs of said transversely extending elongate recess protrude inwardly from a pair of oppositely disposed ridges protruding inwardly from the side walls of the recess.

Each transversely extending elongate recess accommodating a contact blade may also have protruding into the recess from its side walls at least two pairs of oppositely disposed elongate guides which extend downwardly of and are longitudinally spaced along the recess and which serve to locate a contact blade initially as it is introduced into the recess. Each transversely extending elongate recess accommodating a contact blade may also have protruding into the recess from its end walls a pair of oppositely disposed guides which extend downwardly of the recess and which serve to locate a contact blade within the recess with respect to the cable conductor grooves which the recess traverses.

5.

Preferably, the or each recess which is in the other of the two opposed major faces of at least one of the bodies of the improved insulation piercing connector and which accommodates a pressure plate serving to distribute the pressure imparted by tightening of the nut of the or a clamping bolt passing therethrough has protruding into the recess from its side walls four pairs of oppositely disposed ribs sub-divided into two groups longitudinally spaced along the recess and each consisting of two pairs of oppositely disposed ribs longitudinally spaced a short distance apart. Preferably, alsof each recess accommodating a pressure plate has in its bottom wall, four wells each of which is at the foot of two adjacent ribs of one of said groups of pairs of oppositely disposed ribs.

The bottom wall of the or each recess in the other of the two opposite major faces of at least one of the bodies of the improved insulation piercing connector, and the lower and upper surfaces of the pressure plate accommodated therein, preferably each lies on a part of the circumferential surface of an imaginary cylinder of substantially circular cross-section whose axis is substantially parallel to the axes of the cable conductor grooves in said body.

Where it is desired that the improved insulation piercing connector be substantially waterproof, preferably the contact blades disposed in the transversely extending elongate recesses are encapsulated in a resilient rubber-like material.

6.

Each separately formed body of the improved insulation piercing connector preferably is made of a substantially rigid electrically insulating plastics material, one especially suitable plastics material being nylon.

The invention is further illustrated by a description, by way of example, of one preferred insulation piercing connector of the kind described with reference to the accompanying drawings, in which:-

Figure 1 is a side view of the assembled insulation piercing connector; Figure 2 is a plan view of the connector shown in Figure 1 looking in the direction of Arrow A; Figure 3 is a plan view of the connector shown in Figure 1 looking the direction of Arrow B; Figure 4 is an end view of the connector shown in Figure 1 looking in the direction of Arrow C; Figure 5 is a plan view of the inner face of one body of the connector shown in Figure 1; Figure 6 is a sectional side view of the body shown in Figure 5 taken on the line VI-VI, and Referring to the drawings, the preferred insulation piercing connector comprises two separately moulded bodies 1, 11 of nylon, the body having in one of two major faces of the body a pair of parallel grooves 2 transversely spaced apart and the body 11 having in one of two major faces of the body a pair of parallel grooves 12 transversely spaced apart. The two bodies 1, 11, with their grooves co-operating to form two parallel passages 22 for reception of insulated main and supplementary conductors, can be urged together around insulated main and supplementary conductors disposed in the passages by two clampinq bu.Its 23 extending through the bodies between the passages.

The bodies 1, 11 each also has extending transversely of the grooves 2, 12 in said major faces of the bodies three elongate recesses 4, the recesses 4 in the body 1 being shown in Figures 5 and 6, which recesses are longitudinally spaced apart and in each of which can be accommodated a metal contact blade (not shown) which has, in each part of the blade traversing a groove 2, 12, teeth for piercing or displacing the insulation of an insulated conductor disposed in the groove. Figure 4 shows the teeth 27 of contact blades protruding into the passages 22 bounded by the cooperating grooves 2, 12. The contact blades disposed in the transversely extending elongate recesses 4 in the body 1 and in the transversely extending elongate recesses in the body 11 are encapsulated in resilient rubber-like material 28 to render the connector substantially waterproof. A cap 29 can be detachably secured to the connector at either end of the passage 22 for accommodating an insulated supplementary conductor, which cap may contain a water-impermeable grease and can accommodate an end part of an insulated supplementary conductor when disposed in the passage, thereby ensuring 8. that the conductor extends throughout the whole length of the passage and that each of the contact blades will traverse the conductor.

Each of the transversely extending elongate recesses 4 in the body 1, and each of the corresponding transversely extending elongate recesses in the body 11, has protruding into the recess from its side walls two pairs of oppositely disposed ridges 5 longitudinally spaced along the recess. From each ridge 5 protrudes a rib 6 which extends downwardly the full depth of the recess. the ribs protruding front oppositely disposed ridges being so spaced apart that a metal contact blade will be a force fit between them. A well 7 in the bottom wall of each elongate recess 4 extends across the full width of the recess at the foot of each pair of oppositely disposed ribs 6. Each elongate recess 4 also has protruding into the recess from its side walls two pairs of oppositely disposed guides 8 which extend downwardly of and are longitudinally spaced along the recess and from the end walls a pair of oppositely disposed guides 9 which extend downwardly of the recess. When a metal contact blade is introduced into an elongate recess 4, the guides 8 serve to locate the blade initially and the guides 9 serve to locate the blade with respect to the grooves 2, 12 which the recess traverses. Any slivers of insulating material of the moulded body 1 that may be sliced from a rib 6 when the blade is forced into the elongate recess 4 will be collected in the well 7 at the foot of the rib.

9.

The moulded body 1 has in its major face opposite to that in which the grooves 2 are disposed, two rectangular recesses 14 each for accommodating a metal pressure plate 24 serving to distribute the pressure imparted by tightening of the nut of the clamping bolt 23 passing therethrough. The bottom wall of each recess 14 and each of the lower and upper surfaces of the pressure plate 24 each lie on a part of the circumferential surface of an imaginary cylinder of circular cross- section whose axis is parallel to the axes of the grooves 2 in the body 1. Each recess 14 has protruding into the recess from its side walls four pairs of oppositely disposed ribs 15 sub-divided into two groups longitudinally spaced along the recess and each consisting of two pairs of oppositely disposed ribs longitudinally spaced a short distance apart. In the bottom wall of each recess 14 are four wells 16 each of which is at the foot of two adjacent ribs 15 of one of said groups of pairs of oppositely disposed ribs, the wells serving to collect any slivers of insulating material that may be sliced from the ribs as the pressure plate 24 is forced into the recess.

By virtue of the fact that each contact blade will be a force fit between the ribs 6 in the elongate recess 4 in which the contact blade is disposed, risk that the contact blade will remain embedded in an insulated conductor when the two bodies 1, 11 are disengaged is substantially reduced. By virtue of the fact that each 10. pressure plate 24 is a force fit between the ribs 15 in one of the recesses 14, the risk that the pressure plate will be dislodged from the recess or will be so displaced that the pressure exerted by the clamping bolt 23 is insufficient to enable the contact blades to impart a satisfactory electrical connection between insulated main and supplementary conductors is also substantially reduced.

11.

Claims (11)

1. CLAIMS:

   An insulation piercing connector of the kind described, wherein at least one of the recesses accommodating a metal component of the connector has protruding into the recess from its side walls at least two pairs of oppositely disposed ribs which extend downwardly substantially the full depth of and are longitudinally spaced along the recess and between which said metal component is a force fit and has in the bottom wall of the recess at the foot of each rib a well for the collection of any slivers of insulating material that may be sliced from the rib when said metal component is forced into the recess.
2. 2. An insulation piercing connector as claimed in Claim 1, wherein each transversely extending elongate recess accommodating a contact blade has in its bottom wall at least two longitudinally spaced wells each extending across the full width of the recess at the foot of a pair of oppositely disposed ribs.
3. 3. An insulation piercing connector as claimed in Claim 3, wherein each pair of oppositely disposed ribs of each transversely extending elongate recess accommodating a contact blade protrude inwardly from a pair of oppositely disposed ridges protruding inwardly from the side walls of the recess.
4. 4. An insulation piercing connector as claimed in Claim 2 or 3, wherein each transversely extending elongate recess accommodating a contact blade has 12. protruding into the recess from its side walls at least two pairs of oppositely disposed elongate guides which, extend downwardly of and are longitudinally spaced along the recess and which serve to locate a contact blade initially as it is introduced into the recess.
5. 5. An insulation piercing connector as claimed in Claim 4, wherein each transversely extending elongate recess accommodating a contact blade has protruding into the recess from its end walls a pair of oppositely disposed guides which extend downwardly of the recess and which serve to locate a contact blade within the recess with respect to the cable conductor grooves which the recess traverses.
6. 6. An insulation piercing connector as claimed in any one of the preceding Claims, wherein the or each recess which is in the other of the two opposed major faces of at least one of the bodies of the connector and which accommodates a pressure plate serving to distribute the pressure imparted by tightening of the nut of the or a clamping bolt passing therethrough has protruding into the recess from its side walls four pairs of oppositely disposed ribs sub-divided into two groups longitudinally spaced along the recess and each consisting of two pairs of oppositely disposed ribs longitudinally spaced a short distance apart.
7. 7. An insulation piercing connector as claimed in Claim 6, wherein each recess accommodating a pressure plate has in its bottom wall, four wells each of which 13. is at the foot of two adjacent ribs of one of said groups of pairs of oppositely disposed ribs.
8. 8. An insulation piercing connector as claimed in Claim 6 or 7, wherein the bottom wall of the or each recess in the other of the two opposite major faces of at least one of the bodies of the connector, and the lower and upper surfaces of the presssure plate accommodated therein, each lies on a part of the circumferential surface of an imaginary cylinder of substantially circular cross-section whose axis is substantially parallel to the axes of the cable conductor grooves in the body.
9. 9. An insulation piercing connector as claimed in any one of the preceding Claims, wherein the contact blades disposed in the transversely extending elongate recesses of the bodies are encapsulated in a resilient rubberlike material.
10. 10. An insulation piercing connector as claimed in any one of the preceding Claims, wherein each separately formed body of the connector is made of a substantially rigid electrically insulating plastics material.
11. 11. An insulation piercing connector substantially as hereinbefore described with reference to and as shown in the accompanying drawings.