GB2231454A - Connecting busbars with play - Google Patents

Abstract

An electrical connector (1) to connect together, in an articulated manner, adjacent ends (2) of two bus-bars (3), comprises: first and second connector heads (4), of electrically conducting material connectable to the ends (2) of respective bus-bars (3); an elongate, mechanical guide (10) extending between the two connector heads (4) and along which guide (10) at least one connector head (4) is adapted to slide, with play, and an electrical connection between the two connector heads (4) comprising a flexible, electrical conducting braid (12) attached to connector head (4) and having a looped return end (16) adjacent each connector head (4) to provide a rolling braid movement when one connector head (4) is displaced with respect to the other connector head (4). <IMAGE>

Description

ELECTRICAL CONNECTOR This invention relates to an electrical connector for use at an articulated joint between two conductors.

One such joint is described in GB 158789, being part of a cableless power supply system to the electric motor(s) of a mining machine with a pick-up arm of the machine entering the conduit to gain access to the bus-bar(s).

Conventionally, in longwall coal mining a scraper chain conveyor is located along the mineral face serving not only to convey coal won from the face but also to guide and/or support the mining machine in the manner of a rail track. The conveyor is built-up to desired length from unit length (5 ft) line pans located end-to-end, with e.g. dog-bone connectors bridging adjacent pan ends to transmit tensile loads and with end-to-end abutment absorbing compressive loads.During the movement of a winning machine along a conveyor to remove a web of e.g. 2 ft. thickness, the individual line pans are progressively snaked over to the newly exposed mineral face, this snaking movement requiring articulated electrical joints between adjacent bus-bar ends which coincide with the pan ends, and for moderate power supplies. e.g. 2 KW, the joint of GB 1508789 has proved satisfactory, but there is an upper limit to the amount of power that this known articulated joint can safely convey in mine conditions, and there is a continuing use of even greater installed machine power on a single face.

The object of the present invention is to provide an electrical joint for articulated bus-bar ends that is satisfactory from both the mechanical and electrical viewpoints to meet heavy power demands, e.g. l KW.

According to the present invention, there is provided an electrical joint to connect together, in an articulated manner, adjacent ends of two bus-bars, and capable of accommodating, within limits, not only linear but angular movement between the adjacent bus-bar ends, comprising: (i) a first connector head, of electrically conducting material, connectable to an end of a first bus-bar; (ii) a second connector head, of electrically conducting material, connectable to an end of a second bus-bar adjacent that of the first bus-bar; (iii) an elongate, mechanical guide extending between the two heads and along which guide at least one head is adapted to slide, with play, to provide, within limits, not only mutual linear movement between the connector heads but also angular articulation in any direction about the longitudinal axis of the guide; and (iv) an electrical connection between the two heads comprising a flexible, electrical conducting braid attached to each head and having a looped return end adjacent each head to provide a rolling braid movement when one head is displaced with respect to the other head.

Each head is conveniently connectable to its respective bus-bar end by a screw. Each screw is preferably captivated to its head, is preferably self-locking, and is preferably a cap screw having a recessed head for engagement by an alien key. It is also preferred for the bus-bar end to be provided with a serrated seating face to receive an engagement face of each head, which is preferably also serrated, the serrations serving to preclude relative movement between each head and its bus-bar.

The mechanical guide means preferably comprising a pin captivated in one, male head and, in a median position of proximity of the two spaced-apart heads, adapted to be located approximately halfway along a blind receiving bore in the other, female head to accommodate e.g. < 45mm, mutual linear displacement between the heads, and the bore being slightly oversize with respect to the pin diameter to provides for ready linear displacement, while angular articulation can be readily accommodated by constructing the pin from resilient material, e.g. spring steel, to provide in practice < 1.50 articulation.

The conducting braid preferably comprises a planar central portion bridging the two looped return ends, with each return end looped through 1800 at each end of the central portion to terminate in an end which is passed into a clamping aperture in each head and expanded into tight clamping engagement with the aperture by a screw, such as a countersunk head self-tapping screw, while the central portion is preferably housed within an electrically insulating housing.

The bus-bars are supported on spaced-apart electrical insulators carried by an elongate, enclosing casing, and preferably, the connector in accordance with the invention is provided as a readily insertable and removable cartridge, with the insulating housing having a braid barrier constituted by the interconnecting web of a short length of channel section housing of synthetic plastics, and with each head retained in spaced relationship between the opposed inner faces of the parallel sidewalls of the channel section housing by an electrical insulating support pad, the external dimensions of the channel section housing being such that, in use, it will just fit between parallel sidewalls of a channel section phase barrier.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings in which: Figure 1 is a sectional side elevation of an electrical connector in accordance with the invention on the line I-I of Figure 2 connecting together adjacent ends of two bus-bars; Figure 2 is a plan view of Figure 1, and Figure 3 is an end elevation of Figure 1 but with the bus-bars omitted.

In the drawings, an electrical connector 1 connects together, in an articulated manner, adjacent ends 2 of two bus-bars 3, and can be seen to comprise a first and second connector heads 4, of electrically conducting material, connected to the end 2 of one of the bus-bars 3 by a screw 5 engaging a self-locking anchor nut 6 screwed to the bus-bars 3. Each screw 5-, is captivated to its connector head 4, is self-locking, and is a cap screw having a recessed head 7 for engagement by an alien key. The end of each bus-bar adjacent its screw 5, is provided with a serrated seating face 8 to receive a similarly serrated engagement face 9 of each head 4.

An elongate, mechanical guide in the form of a spring pin 1B, extends between the two connector heads 4. In detail the pin 18 e.g. of spring steel is captivated in one, male connector head, being the connector head to the right hand side of Figures 1 and 2, and in a median position of proximity of two the spaced-apart connector heads - which position illustrated in Figures 1 and 2 - is adapted to be located approximately halfway along a blind receiving bore 11 in the other female connector head, being the connector head to the left hand side of Figures 1 and 2, the bore 11 is slightly oversize with respect to the diameter of the pin 1B to provide for ready linear displacement e.g., < 45 mm, while angular articulation is readily accommodated by constructing the pin 1B from spring steel, to provide in practice < 1.50 articulation.

An electrical connection between the two connector heads 4, is provided by a flexible, electrical conducting braid 12 attached to each connector head 4 by a braid end 13 passed into a clamping aperture 14 in each connector head 4, and expanded into tight clamping engagement with the aperture 14 by a countersunk head self-tapping screw 15.The braid 12 also has looped return ends 16 adjacent each connector head 4, to provide a rolling braid movement when one connector head 4 is displaced with respect to the other connector head 4, while the braid 12 further comprises a planar central portion 17 bridging the two braid ends 13, with one looped return end 16 at each end of the central portion 17, the latter being housed within a short length of channel-section, electrically insulating housing 18 of synthetic plastics having a braid barrier constituted by the interconnecting web 19 and with each connector head 4, retained in spaced relationship between the opposed inner faces 2 of the parallel sidewalls 21 of the housing 18, by an electrical insulating support pad 22, the external dimensions of the short length channel housing 18 being such that it will just fit between parallel sidewalls 23 of a channel section phase barrier 24.

The bus-bars 3 are supported on spaced-apart electrical insulators (not shown) and the connector 1 in accordance with the invention is conveniently provided as a readily insertable and removable cartridge, having a braid barrier constituted by the interconnecting web 19 and with each connector head 4, retained in spaced relationship between the opposed inner faces 2 of the parallel sidew all s 21 of the housing 18, by an electrical insulating support pad 22, the external dimensions of the short length channel housing 18 being such that it will just fit between parallel sidewalls 23 of a channel section phase barrier 24.

Claims (17)

1. An electrical joint to connect together, in an articulated manner, adjacent ends of two bus-bars, and capable of accommodating, within limits, not only linear but angular movement between the adjacent bus-bar ends, comprising: (i) a first connector head, of electrically conducting material, connectable to an end of a first bus-bar; (ii) a second connector head, of electrically conducting material, connectable to an end of a second bus-bar adjacent that of the first bus-bar; (iii) an elongate, mechanical guide extending between the two heads and along which guide at least one head is adapted to slide, with play, to provide, within limits, not only mutual linear movement between the connector heads but also angular articulation in any direction about the longitudinal axis of the guide; and (iv) an electrical connection between the two heads comprising a flexible, electrical conducting braid attached to each head and having a looped return end adjacent each head to provide a rolling braid movement when one head is displaced with respect to the other head.

2. An electrical joint as claimed in Claim 1, wherein each head is connectable to its respective bus-bar end by a screw.

3. An electrical joint as claimed in Claim 2, wherein each screw is captivated to its head.

4. An electrical joint as claimed in Claim 2 or Claim 3, wherein each screw is self-locking.

5. An electrical joint as claimed in any one of Claims 2 to 4, wherein each screw is a cap screw having a recessed head for engagement by an alien key.

6. An electrical joint as claimed in any preceding Claim, wherein each connector head is serrated at an engagement face thereof.

7. An electrical joint as claimed in any preceding Claim, wherein the mechanical guide means comprises a pin captivated in one, male head and, in a median position of proximity of the two spaced-apart heads, adapted to be located approximately halfway along a blind receiving bore in the other, female head to accommodate mutual linear displacement between the heads, and the bore being slightly oversize with respect to the pin diameter to provides for ready linear displacement.

8. An electrical joint as claimed in Claim 7, wherein the mutual linear displacement is < 45 mm.

9. An electrical joint as claimed in Claim 7 or Claim 8, wherein the angular articulation is accommodated by constructing the pin from resilient material.

1B. An electrical joint as claimed in Claim 9, wherein the pin is of spring steel.

11. An electrical joint as claimed in any preceding Claim, wherein the angular articulation is < 1.50.

12. An electrical connector as claimed in any preceding Claim, wherein the conducting braid comprises a planar central portion bridging the two looped return ends, with each return end looped through 1800 at each end of the central portion to terminate in an end which is passed into a clamping aperture in each head and expanded into tight clamping engagement with the aperture by a screw.

13. An electrical connector as claimed in Claim 12, wherein each screw is a counter sunk head self-tapping screw.

14. An electrical connector as claimed in Claim 12 or Claim 13, wherein the central portion is housed within an electrically insulating housing.

15. An electrical connector as claimed in Claim 14, wherein the electrically insulating housing constitutes a braid barrier comprising an interconnecting web of a short length of channel section housing of synthetic plastics, and with each head retained in spaced relationship between the opposed inner faces of the parallel sidewalls of the channel section housing by an electrical insulating support pad, the external dimensions of the channel section housing being such that, in use, it will just fit between parallel sidewalls of a channel section phase barrier.

16. An electrical connector as claimed in Claim 14 or Claim 15, provided as a readily insertable and removable cartridge.

17. An electrical connector substantially as hereinbefore described with reference to the accompanying drawings.