AU2003203525B2 - A Plug for a Mine Cable - Google Patents

Description

S&FRef: 631510

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address of Applicant Actual Inventor(s): Address for Service: Invention Title: New Macey Pty Limited 39 Laverick Avenue Tomago New South Wales 2322 Australia Laurence David Macey Spruson Ferguson St Martins Tower Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) A Plug for a Mine Cable ASSOCIATED PROVISIONAL APPLICATION DETAILS [33] Country [31] Applic. No(s) AU PS1473 [32] Application Date 02 Apr 2002 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815c A Plug for a Mine Cable Technical Field The present invention relates to cable plugs and more particularly but not exclusively to cable plugs employed in the mining industry.

s Background of the Invention In the mining industry, it is not uncommon for electrical equipment to require connection to a supply of high voltage and high current. Typically, the cables employed are three-phased cables having three active wires, three earth wires and a pilot wire. The pilot wire being provided to electrically disconnect the cable should the cable beconie cut.

The plugs employed with such cables therefore have three active connection members at each end such as a pin or female electrical coupling, and three'earth connections.

For repair, servicing and safety checks, it is necessary to be able to access the integrity of each earth wire. To do this, it has been necessary to dismantle at least one of the cable plugs so that the earth wires are electrically isolated at one end of the cable. A known instrument is then used to check the earth wire. Once checked the plug is reassembled. Such a procedure is time consuming, often taking several hours.

Accordingly, these known procedures for checking earth wires is generally expensive particularly if it requires "downtime" in respect of mining machinery.

Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages of known cable plugs.

Summary of the Invention There is disclosed herein a cable plug for a cable having at least one active wire and at least two earth wires, said plug including: a plug body; an active connection member, for each active wire, mounted in the body and to which an active wire is to be electrically connected; an earth mounting, for each earth wire, in the body to which an earth wire is to be connected for electrically connecting the earth wires to the body, the mountings including an insulation material to be located between the earth wires and body; a conductor to electrically connect each earth wire to the body, each conductor having a first operative position electrically connecting an associated one of the wires to \LIBTT]03030.doc:yxa:hxa the body, and a second operative position not electrically connecting the associated earth wire to the body; and access means providing electrical access to each earth wire when the associated conductor is in the second position thereof.

Preferably, said insulation material is a dialetric material.

Preferably, said access means is a passage within which said connector is located, with the connector when in said second position being displaced from said passage so that said passage provides said access means.

Preferably, said passage is threaded and said connector is threadably engaged 1o therein when in said first position.

Preferably, said plug is adapted to receive three active wires and three earth wires so that said plug has three connector members, three earth mountings and three connectors.

There is further disclosed herein an earth test connector for the above plug, the test connector includes a body of electrically insulating material having a projection to project into said access means, and an electrically conductive member extending through said body including said projection to engage the associated earth wire to enable a user to test the earth wire.

Preferably, said projection is threaded so as to threadably engage with said passage.

Brief Description of the Drawings A preferred form of the present invention will now be described by way of example with reference to the accompanying drawing which schematically depicts in part section, side elevation a plug for a cable employed in the mining industry.

Detailed Description of the Preferred Embodiments In the accompanying drawings, there is schematically depicted a plug 10. The plug 10 would be attached to a cable 11 which in this embodiment is used to provide electric power to a piece of mining equipment. The cable 11 is a three phased cable in that it has three active wires 12, and three earth wires 13. In addition to the wires 12 and 13 there is a pilot wire 14.

The plug 10 includes a body 15 which receives and supports active connection members 16. In this embodiment, the connection members 16 are female connections intended to receive a pin of an associated coupling. The connection members 16 are secured to a base 17 by means of a threaded fastener 18. The base 17 has a cavity 19 [R:\LIBTT03030. doc:yxa:hxa within which an end of the wire 12 is located. Threaded fasteners 20 engage the wire 12 to secure the wire 12 to the base 17 so that it is electrically connected to the member 16.

The pilot wire 14 is similarly connected to a base 17 and has a connection member 16.

The earth wire 13 illustrated is received within a mounting 23. More particularly, the mounting 23 provides a passage 21 within which an end of the wire 13 is inserted.

Located within the passage 21 is an insulator 22. Preferably, the insulator 22 is a sleeve formed of dialetric material.

The mounting 23 is also provided with a threaded passage 24 within which a threaded fastener 25 is received. The threaded fastener 25 is formed of electrically conductive material so that when engaged with the wire 13, it electrically connects the wire 13 and the body The threaded fastener 25 can be removed so that the passage 24 provides an access means in respect of the wire 13. With the threaded fastener 25 removed, an earth test connector 26 can be used to provide electrical access to the wire 13. The test connector 26 includes a body 27 formed of plastics material so as to longitudinally insulate a conducting member 28. More particularly, the body 27 includes a head 29 from which there extends a threaded projection 30. The projection 30 is threadably engaged within the passage 24 so that the extremity 31 may be brought into electric contact with the earth wire 13. The conductor 28 can then be employed to test the wire 13 while the wire 13 is electrically isolated from the body 15 and the other earth wires 13 (not illustrated).

The earth wires 13 are tested by applying a test instrument to the outer end 32 of the conductor 28.

Once the wire 13 has been tested, the test connector 26 is removed and the threaded fastener 25 reinserted so that the wire 13 is electrically connected to the body The above described preferred embodiment substantially reduces the time required (and therefore cost), in checking the integrity of each earth wire 13.

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Claims (9)

1. A cable plug for a cable having at least one active wire and at leat two earth wires, said plug including: a plug body; an active connection member, for each active wire, mounted in the body and to which an active wire is to be electrically connected; an earth mounting, for each earth wire, in the body to which an earth wire is to be connected for electrically connecting the earth wires to the body, the moutitings including an insulation material to be located between the earth wires and body; to a conductor to electrically connect each earth wire to the body, each conductor having a first operative position electrically connecting an associated one of the wiies to the body, and a second operative position not electrically connecting the associatediearth wire to the body; and access means providing electrical access to each earth wire when the associated is conductor is in the second position thereof. I

2. The plug of claim I wherein, said insulation material is a dialetric material.

3. The plug of claim 1 or 2 wherein, said access means is a passage within which said connector is located, with the connector when in said second position being displaced from said passage so that said passage provides said access means.

4. The plug of claim 3 wherein, said passage is threaded and' said connector is threadably engaged therein when in said first position.

The plug of any one of claims 1 to 4 wherein, said plug is adapted to receive three active wires and three earth wires so that said plug has three connector members, three earth mountings and three connectors.

6. In combination an earth test connector and the plug of any one of claims 1 to 5 wherein, the test connector includes a body of electrically insulating material having a projection to project into said access means, and an electrically conductive member extending through said body including said projection to engage the associated earth wire to enable a user to test the earth wire.

7. The combination of claim 6 wherein, said projection is threaded so as to threadably engage with said passage. [R:ULBTT]03030 doc:yxa:hxa

8. A cable plug, substantiates hereinbefore described with refeence to the accompanying drawing.

9. In combination a cable plug and earth test connector, substantiates hereinbefore described with reference to the accompanying drawing. Dated 2 April, 2003 New Macey Pty Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R:LJBTT]03030 doc:y &hl