GB2214003A - Electrical connector - Google Patents

Abstract

Electrical connection apparatus for simultaneously providing more than one intrinsically safe electrical connection system uses connectors comprising matable components 10. Each component 10 has a plurality of terminal pins 12 or socket members. The pins and sockets are divided into groups 14, each group 14 providing all of the connections in a respective electrical system of intrinsic safety type. The pins of each group 14 are separated from any neighbouring group by a distance sufficiently large to provide adequate safety according to a standard such as CENELEC standard EN 50020, for instance by omitting one column 20 of pins. <IMAGE>

Description

Electrical Connection The present invention relates to electrical connection arrangements and apparatus and arises from an appreciation of the difficulties of providing safe electrical supplies in hostile environments, such as mines.

Mining equipment is increasingly sophisticated and much of the equipment now used in mines requires electrical connections. These connections may be power supplies and may also include paths for data or other communication. For instance, a computer may be used to control a gas detection system. The computer and each sensor may require an electrical power supply and data communication paths will be required between the compuLer and each sensor.

The dangerous environment below ground places severe constraints on the design of electrical systems in order to ensure adequate safety. A known arrangement is arranged to provide "intrinsic safety". The electrical connection requirements in the mine are analysed and divided into a number of systems of connections. The power conducted by the connections of any system is limited so that even if any of the cables of one system inadvertently short, the maximum power available is limited and within accepted safety limits. In order to maintain the integrity of this form of protection, each system must be well insulated to minimize the risk of shorts between systems. A power supply to an underground machine may for instance be provided by a continuous run of earth screened cable from a generator at a remote location to the machine at its underground location.The use of screened cables minimizes the risk of accidental or inadvertent exposure of the conductors.

Difficulties with this arrangement arise from the continual movement of machines during working. The cables must be regularly replaced with longer or shorter cables.

The present invention seeks to obviate or mitigate these and other disadvantages.

According to the present invention there is provided an electrical connection arrangement comprising two components which can mate, each component having a plurality of terminal members which come into electrical contact with a corresponding terminal member of the other component when the components are mated, the terminal members of each component being divided into groups which form connections in respective electrical systems, each group being separated from any neighbouring group by a distance which is sufficiently large to provide a desired degree of safety between neighbouring groups.

The desired degree of safety may be determined by reference to CENELEC standard EN 50020.

The terminal members of each component may be located at points which form a regular array, the nearest terminal members of neighbouring groups being at array points which are adjacent and on respective sides of an array point at which no terminal member is located or at which there is located a terminal member which does not form part of a group.

The array may be a rectilinear array. Terminal members of neighbouring groups may be separated by a line of array points, whereby the closest spacing of terminal members of neighbouring groups is twice the spacing of array points. The array may be a rectangular array of points arranged in perpendicular rows and columns. The terminal members of neighbouring groups may be separated by a line of array points which extends fully across the array.

Preferably earthed terminal members are located between the terminal members of neighbouring groups.

Preferably at least two earthed terminal members are provided between each pair of neighbouring groups.

Preferably the terminal members of each component are mounted on a substrate, the terminal members being located at a substrate face which confronts a similar substrate face when two components are mated, the terminal members extending into the substrate on which they are mounted and being connected to conductors of the electrical system at locations remote from the said substrate face. Preferably the terminal members extend through the substrate to a second substrate face and are connected to the conductors at the second face. The terminal members may comprise pin members and socket members. The terminal members may be removably attached to a substrate, whereby they may be removed from locations between neighbouring groups.

Preferably the matable components comprise locking means for retaining components in the mated condition.

Preferably a barrier member is provided between the said remote locations corresponding to respective electrical systems. Preferably the barrier member is earthed. The barrier member may be connected to a terminal member located between neighbouring groups. The barrier member is preferably connected to at least two terminal members as aforesaid. The barrier member may comprise a clamp member by which a conductor may be electrically connected to the barrier member.

In another aspect, there is provided electrical connection apparatus comprising two terminal boxes and cable extending between the terminal boxes, the cable being connected to electrical conductors within the terminal boxes by electrical connection arrangements as aforesaid.

Preferably the cable comprises a plurality of cable lengths each of which has a matable component as aforesaid at both ends, whereby the cable lengths may be connected end to end.

Preferably each terminal box provides means for connecting equipment to the conductors of a selected electrical system.

The apparatus may further comprise a junction box for connection between cable lengths by means of matable connections, one component of each connection forming part of the junction box. The junction box may comprise means providing electrical connections between the connection components which form part of the junction box, to allow corresponding conductors of each cable to be in electrical connection through the junction box. The junction box preferably further comprises means for connecting equipment to the conductors of a selected electrical system.

The junction box may further comprise isolator means connected within the junction box to the connections of the selected electrical system, the isolation means being operable to isolate the portions of the connections to either side of the isolator means and the means for connecting equipment being operable to connect the equipment selectively to the portions.

One embodiment of an electrical connection arrangement and electrical connection apparatus according to the invention will now be described by way of example only and with reference to the accompanying drawings in which Fig. 1 is a schematic view of the face of one component of an electrical connection arrangement according to the invention; Figs. 2 and 3 are sections along lines 2-2 and 3-3 of Fig. 1; Fig. 4 is a view of the whole barrier plate shown in Fig. 3 and from the same view point; and Fig. 5 is a highly schematic diagram of electrical connection apparatus according to the invention installed for use.

Fig. 1 shows the face of one component 1û of an electrical connection arrangement comprising two components which can mate. The component 10 has a plurality of terminal members 12 in the form of pins.

Each of these comes into electrical contact with a corresponding socket member (not shown) of the other component when the components are mated. The terminal pins 12 are divided into groups of eight pins indicated by broken lines 14. Each group 14 of pins 12 provides all of the connections in a respective electrical system of the "intrinsic safety" type. The pins 12 of each group 14 are separated from the pins of any neighbouring group by a distance which is sufficiently large to provide a desired degree of safety between neighbouring groups. The degree of safety required, and hence the spacing, can be determined by reference to an appropriate industry standard, such as CENELEC standard EN 50020.

The pins 12 are mounted in a substrate 16 and extend through the substrate to project forwardly and to the rear. The forward projecting portion of each pin 12 will mate with a corresponding socket mounted in a similar manner on a substrate of another component when the two components are brought together. The rearward portion projects to provide for connection between the pins 12 and wires 18. The wires carry sufficient insulation to meet safety requirements with regard to shorting between wires of the same system. The wire insulation will ensure that safety requirements are met along the length of the wires away from the substrate 16, but further steps are necessary to ensure that safety requirements are met in the immediate vicinity of the substrate 16.In particular, it is necessary to ensure adequate safety in the event that a wire becomes detached from its pin 12 to prevent shorts occurring between systems.

The possibility of a loose wire shorting to a wire of another system is first reduced by providing sufficient spacing between the pins 12 of respective groups 14. In the arrangement shown, the pins are arranged on a rectangular grid having columns of four pins and perpendicular rows of eight pins. Each group of eight pins is formed by two columns of four pins and neighbouring groups 14 are separated by a column 20 of the array. The columns 20 provide a buffer zone between groups 14.

The pins 12 are removably mounted in the substrate 16 so that the number of pins in a group and the location and layout of groups can be altered. In the example shown, the top and bottom pin in each buffer zone 20 is redundant and may be removed to leave only two pins. The locations of the removed pins are indicated by small crosses in Fig. 1. The two buffer zone pins 22 are used to mount a barrier plate 26 which further reduces the risk of shorting between groups.

The plate 26 is generally rectangular and has two lugs 28 located to allow connection to the pins 22. The plate 26 is made of conducting material and when installed, as shown in Fig. 3, provides a barrier between the wires 18 of adjacent groups 14. This barrier will prevent disconnected wires 18 from coming into contact with wires from another group.

The plates 26 are also earthed and so may short loose wires to earth. To provide for earthing each plate 26, has one or more clamping arms 30 attached by means of screws 32. The clamp arms 30 allow the earth screen (not shown) of a system to be clamped to the plate to provide a secure earth. An earth screen is normally clamped in this way in each connector at the end of a cable run. In junction and terminal boxes (to be described) earth wires are normally attached to the plates 26 by means of ring crimps mounted as an alternative in the sockets for the screws 32.

The two buffer zone pins 22 are consequently earthed by their connection to the plate 26.

Interconnection of the pins 22 and corresponding sockets on another component therefore provides for two earth connections to be carried through, independently of any of the systems. This duplication minimises the possibility of losing the required earth between each system.

The substrate 16 and its associated pins, plates and wires is mounted for use in a housing which protects the component from damage and which is designed so that when two components are mated, with pins and sockets connected, the whole assembly is entirely surrounded by the housings, the wires leaving the housing in a protective sheath. Some means for locking the components together is preferably provided. If the wires of more than one system leave the housing in the same cable, they will be separated within the cable by earthed sheaths.

Fig. 5 shows a system in which a number of components as described are used to provide electrical connections for four different systems such as could be used in a mine. The apparatus shown in Fig. 5 comprises two terminal boxes 40 and cable lengths 42 extending between the terminal boxes 40. The cable lengths 42 are connected to electrical conductors within the terminal boxes by electrical connection arrangements 44 each formed by two components of the type described above.

In more detail, the apparatus comprises a first terminal box 40A which is situated at the surface or other safe area, and a second terminal box 40B which may be located at the workface of a mine, for instance. These are connected by lengths of protective cable. Three cable lengths 42 are shown. Each cable length provides sufficient connections for four systems and these connections are made between the pins of connection components of the type described above, mounted at ends of the cable lengths. Two cable lengths 42 are connected end to end between the terminal box 40A and a junction box 46 to be described in more detail below. A further cable length 42 connects the junction box 46 to the terminal 408. In the following description, the term "highway" will be used to refer to the set of connections provided for one system by a cable length. Thus, one system of connections is provided by one highway of the four highway cable lengths shown.

The terminal box 40A has a connection component for mating with the component on the end of a cable length 42. The four systems are distributed within the box 40A to respective connector blocks 48. The connector blocks 48A,488 and 48D are used to connect three generators 50A,50B and 50D into the corresponding systems. No connection to the remaining system is made in the terminal box 40A, but could be made by way of the connector block 48C.

The connections from the generators 50 are carried by respective highways of the cable lengths 42 to the junction box 46 in which the systems are similarly distributed to four isolator blocks 52A,52B,52C and 52D.

Connections are also provided in the junction box 46 from the isolator blocks 52 to a second connection component, for connection to the highways a second cable length 42, for onward connection of the systems to the terminal box 408 which is identical to the junction box 40A.

However, not all four of the systems are carried through the junction box 46. The isolator block 52D provides a connection for a machine 54 which is therefore connected to the generator 50D but no forward connection is made to the terminal box 408. That is, the corresponding highway of the cable length 42 between the junction box 46 and terminal box 408 is completely isolated. Conversely, the isolator block 52C is configured to provide a connection between a piece of apparatus 56 such as a sensor readout, and a sensor 58 located near the workface, but there is no connection of this system badk to the surface. The sensor 58 can therefore be read remotely but within the mine itself.

The isolator block 528 is configured to provide a simple through connection for the corresponding system which accordingly provides a connection between the generator 50B and a machine 60 at the workface, but no intermediate connections to other equipment.

Finally, the isolator block 52A provides both a through connection between the generator 50A and apparatus 62 at the workface and also provides for the connection of further apparatus 64 into this system by means of the junction box 46.

The isolator blocks 52 are re-configurable so that the various possible interconnections can be selected and changed as the working requirements in the mine change.

The configurations available will depend on the design of the blocks 52, and it may be appropriate in some circumstances to provide for other configurations or other selections of configurations. It will be apparent from the above description that if, for instance, the machine 54 and the apparatus 56 and 64 was no longer required, the junction box could be disconnected from the neighbouring cable lengths 42 which could then be connected directly together. A junction box can be connected into the apparatus at any point where two cable length ends are connected thus providing considerable flexibility in the location and interconnection of equipment, power supplies etc..As work progresses and the workface retreats, the terminal box 408 can be moved along with the work face simply by disconnecting it from the cable length and introducing further cable lengths as necessary, with minimal disruption to the operation of the systems. Each time a further cable length is introduced, another location is created at which a junction box can be used.

In the apparatus described, safety requirements are met by the presence of barrier plates 26 (not shown in Fig. 5) between groups of terminal members in each component of every connection arrangement. Two earths are carried through the whole apparatus between each neighbouring system for additional safety.

It will be understood from the above that many modifications and variations of the apparatus described can be made without departing from the spirit and scope of the present invention. The arrangement of pins on the substrate can be changed. In the above embodiment all of the pins are identical but in situations where both power supplies and data or other forms of communication are provided, different size pins and wires could be used.

More or less than four systems can be provided and other facilities for connection into the systems could be provided in junction and terminal boxes.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims (1)

1. An electrical connection arrangement comprising two components which can mate, each component having a plurality of terminal members which come into electrical contact with a corresponding terminal member of the other component when the components are mated, the terminal members of each component being divided into groups which form connections in respective electrical systems, each group being separated from any neighbouring group by a distance which is sufficiently large to provide a desired degree of safety between neighbouring groups.

2. An arrangement according to claim 1, wherein the desired degree of safety is determined by reference to CENELEC standard EN 50020.

3. An arrangement according to claim 1 or 2, wherein the terminal members of each component are located at points which form a regular array, the nearest terminal members of neighbouring groups being at array points which are adjacent and on respective sides of an array point at which no terminal member is located or at which there is located a terminal member which does not form part of a group.

4. An arrangement according to claim 3 wherein the array is a rectilinear array.

5. An arrangement according to claim 4, wherein terminal members of neighbouring groups are separated by a line of array points, whereby the closest spacing of terminal members of neighbouring groups is twice the spacing of array points.

6. An arrangement according to claim 4 or 5, wherein ,.

the array is a rectangular array of points arranged in perpendicular rows and columns.

7. An arrangement according to claim 6, wherein the terminal members of neighbouring groups are separated by a line of array points which extends fully across the array.

8. An arrangement according to any preceding claim, wherein earthed terminal members are located between the terminal members of neighbouring groups.

9, An arrangement according to claim 8, wherein at least two earthed terminal members are provided between each pair of neighbouring groups.

10. An arrangement according to any preceding claim, wherein the terminal members eof each component are mounted on a substrate, the terminal members being located at a substrate face which confronts a similar substrate face when two components are mated, the terminal members extending into the substrate on which they are mounted and being connected to conductors of the electrical system at locations remote from the said substrate face.

11. An arrangement according to claim 10, wherein the terminal members extend through the substrate to a second substrate face and are connected to the conductors at the second face.

12. An arrangement according to any preceding claim, wherein the terminal members comprise pin members and socket members.

13. An arrangement according to claim 10, 11 or 12, wherein a barrier member is provided between the said remote locations corresponding to respective electrical systems.

14. An arrangement according to claim 13, wherein the barrier member is earthed.

15. An arrangement according to claim 13 or 14, wherein the barrier member is connected to a terminal member located between neighbouring groups.

16. An arrangement according to claim 15, wherein the barrier member is connected to at least two terminal members as aforesaid.

17. An arrangement according to any of claims 13 to 16, wherein the barrier member comprises a clamp member by which a conductor may be electrically connected to the barrier member.

18. An arrangement according to any preceding claim, wherein the terminal members are removably attached to a substrate, whereby they may be removed from locations between neighbouring groups.

19. An arrangement according to any preceding claim, wherein the matable components comprise locking means for retaining components in the mated condition.

20. An electrical connection arrangement substantially as described above with reference to Figs. 1 to 4 of the accompanying drawings.

21. Electrical connection apparatus comprising two terminal boxes and cable extending between the terminal boxes, the cable being connected to electrical conductors within the terminal boxes by electrcal connection arrangements according Lo any preceding claim.

22. Apparatus according to claim 21, wherein the cable comprises a plurality of cable lengths each of which has a matable component as aforesaid at both ends, whereby the cable lengths may be connected end to end.

23. Apparatus according to claim 21 or 22, wherein each terminal box provides means for connecting equipment to the conductors of a selected electrical system.

24. Apparatus according to claim 21, 22 or 23, and further comprising a junction box for connection between cable lengths by means of matable connections as aforesaid, one component of each connection forming part of the junction box.

25. Apparatus according to claim 24, wherein the junction box comprises means providing eletrical connections between the connection components which form part of the junction box, to allow corresponding conductors of each cable to be in electrical corinection through the junction box.

25. Apparatus according to claim 24 or 25, wherein the junction box comprises means for connecting equipment to the conductors of a selected electrical system.

27. Apparatus according to claim 26, wherein the junction box comprises isolator means connected within the junction box to the connections of the selected electrical system, the isolator means being operable to isolate the portions of the connections to either side of the isolator means, and the means for connecting equipment being operable to connect the equipment selectively to the portions.