AU2008258184A1

AU2008258184A1 - A cable terminal lug

Info

Publication number: AU2008258184A1
Application number: AU2008258184A
Authority: AU
Inventors: Bruce James Ogden
Original assignee: CABLE ACCESSORIES AUSTRALIA PT
Current assignee: CABLE ACCESSORIES (AUSTRALIA) PTY Ltd
Priority date: 2007-12-21
Filing date: 2008-12-17
Publication date: 2009-07-09
Anticipated expiration: 2028-12-17
Also published as: AU2008258184B2; NZ573715A

Description

S&F Ref: 888543 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Cable Accessories (Australia) Pty. Ltd., of Applicant: an Australian company, ACN 002 184 616, of 26 Derby Street, Silverwater, New South Wales, 2128, Australia Actual Inventor(s): Bruce James Ogden Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: A cable terminal lug The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(1897004_1) 1 A CABLE TERMINAL LUG Field of the Invention The present invention relates to a cable terminal lug, and particularly relates to, but is not restricted to, a cable terminal lug for electrical sector cables. 5 Background of the Invention Electrical sector cables are used for the distribution of electricity in underground network systems. Sector cables typically comprise a round single insulated cable with four individual cores arranged internally as four separate sector conductors representing four phases/sectors, each of which is separately insulated. The sector cables typically 10 have their ends extending up through the ground surface where they are terminated in above ground plastic pillar boxes. A length of approximately 300 mm of cable typically extends above the ground surface and the individual sector conductors for each phase are individually separated. Each of the conductors is then terminated by crimping the barrel portion 2 of a standard crimping-type cable terminal lug 1, depicted in Figures 1 and 2 of is the accompanying drawings, onto the exposed end portion of the conductor. Lugs 1 are connected to bus bars by way of a bolt passing through the mounting aperture 4 in the palm 3 of each terminal lug, with a nut completing the connection. Sector conductors typically have a generally triangular cross-section, forming a 900 sector of the circular cross-section of the round cable, with a cross-sectional area of 20 either approximately 240 sq mm or approximately 185 sq mm, and are predominantly formed of aluminium. Sector conductors may either be in the form of stranded wire conductors or solid conductors, however both forms of conductors are typically terminated using cable terminal lugs I as described above. To enable connection of a pair of terminated conductors by way of a bus bar, the 25 palms 3 of the cable terminal lugs I and the bus bar must be closely aligned. Even when a standard cable terminal lug 1 appears to be aligned prior to operation of the crimping tool to secure the cable terminal lug 1 on the conductor, movement of the cable terminal lug as the tool is applied often occurs. This results in misaligned cable terminal lugs I which cannot be readily connected by way of a bus bar. The stiffness of the conductors, 30 and the short length of conductor exposed above the ground, prevent the conductor from being twisted and bent to provide better alignment after crimping.

2 Whilst various solutions to the above problem have previously been proposed, most solutions are not suitable for use with both solid and stranded wire conductors. Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at 5 least one of the above disadvantages. Summary of the Invention There is disclosed herein a cable terminal lug comprising: an electrically conductive first section having a leading palm portion with a mounting aperture extending therethrough and a trailing first barrel portion, said first 1o barrel portion defining a substantially cylindrical cavity and being deformable by crimping; and an electrically conductive second section having a leading second barrel portion and a trailing third barrel portion coaxially extending from said second barrel portion, said second barrel portion being adapted to be received and retained in said cavity so as to is be rotatable within said cavity, said third barrel portion having a diameter greater than a diameter of said second barrel portion, said third barrel portion defining a tunnel for receipt of an electrical conductor, said second and third barrel portions being deformable by crimping. Typically, said second barrel portion is adapted to be retained in said cavity with 20 an interference fit. Typically, said second barrel portion is adapted to be retained in said cavity by engagement of a protuberance formed on one of said second barrel portion and a wall of said cavity and an annular groove formed in the other of said second barrel portion and said wall of said cavity. 25 In one form, said cavity is a blind cavity. Typically, said diameter of said third barrel portion is substantially equal to a diameter of said first barrel portion. In a preferred form, an annular shoulder is defined between said second barrel portion and said third barrel portion. 30 In a preferred form, said tunnel extends through both said second and third barrel portions.

3 There is further disclosed herein a method of terminating an electrical conductor utilizing a cable terminal lug as defined above, said method comprising the steps of: (a) inserting a bare end section of an electrical conductor in said tunnel; (b) forming a first crimp on said third barrel portion to secure said bare end s section of aid electrical conductor within said tunnel; (c) inserting said second barrel portion within said cavity; (d) rotating said first section relative to said second section so as to locate said palm portion in a desired orientation; and (e) forming a second crimp on said first barrel portion so as to secure said 1o second barrel portion within said cavity. Step (c) may be carried out prior to step (a). The second crimp may be formed on both said first and third barrel portions. Brief Description of the Drawings A preferred form of the present invention will now be described by way of 15 example with reference to the accompanying drawings, wherein: Figure 1 is a plan view of a prior art cable terminal lug; Figure 2 is a side elevation view of the prior art cable terminal lug of Figure 1; Figure 3 is a perspective view of a cable terminal lug according to a preferred embodiment of the present invention with two sections thereof separated; 20 Figure 4 is a partially cross-sectioned side elevation view of the cable terminal lug of Figure 3; Figure 5 is an enlarged fragmentary cross-sectional view of the connection between the first and second sections of the cable terminal lug of Figure 3; and Figure 6 is a trailing end view of the second section of the cable terminal lug of 25 Figure 3. Detailed Description of the Preferred Embodiments Referring to Figure 3 of the accompanying drawings, a cable terminal lug 100 comprises an electrically conductive first section 101 and an electrically conductive second section 102. For use with aluminium conductors, the cable terminal lug 100 will 30 typically have a bi-metal construction, with the first section 101 formed of copper and the second section 102 formed of aluminium.

4 The first section 101 has a leading palm portion 103 with a mounting aperture 104 extending therethrough for mounting the cable terminal lug 100 on a bus bar, by way of a bolt extending through the mounting aperture 104 in the usual manner. The first section 101 also has a trailing first barrel portion 105 extending from the palm portion s 103. The first barrel portion 105 defines a cylindrical cavity 106, best depicted in Figure 4, that opens onto the trailing face 107 of the first barrel portion 105. In the embodiment depicted, the cavity 106 is a blind cavity. The second section 102 has a leading second barrel portion 108 and a trailing third barrel portion 109 that coaxially extends from the second barrel portion 108. The io second barrel portion 108 has a substantially cylindrical outer wall 110 that has a diameter slightly less than that of the cavity 106 in the first barrel section 105. Specifically, the outer wall 110 has a diameter of 28.0mm whereas the cavity 106 has a diameter of 28.1mm in the arrangement depicted. The length of the second barrel portion 108 is also approximately equal to, or shorter than, the depth of the cavity 106. The is second barrel portion 108 is able to be received within the cavity 106 such that it is rotatable within the cavity 106. As a result, the angular orientation of the palm 103 relative to the second section 102 is infinitely adjustable. The first and second sections 101, 102 are also configured such that the second barrel portion 108 is retained within the cavity 106. In the arrangement depicted, 20 particularly in Figure 5, an annular protuberance 111 is formed on the wall 112 of the cavity 106 and a corresponding annular groove 113 is formed in the outer wall 110 of the second barrel portion 108. When the second barrel portion 108 is inserted into the cavity 106, the protuberance 111 engages the groove 113 so as to retain the second barrel portion 108 within the groove 106 and also to provide an interference fit between the 25 second barrel portion 108 and the first barrel portion 105. This eases the handling, of the lug 100, preventing the two sections from readily falling apart during handling whilst still enabling rotation of the first section 101 in relation to the second section 102 with manual pressure or, depending upon the level of interference fit, at least with the use of hand tools. 30 Whilst, in the arrangement depicted, the protuberance 111 is annular, one or more discrete protuberances could be utilised as an alternative. Similarly, rather than providing the protuberance 11l on the cavity wall 112 and the groove 113 in the outer wall 110 of the second barrel portion 108, the groove could just as well be formed in the 5 cavity wall 112 with the protuberance formed on the outer wall 110 of the second barrel portion 108. A tunnel 114 is defined extending through the second and third barrel portions 108, 109 for receipt of an electrical conductor, which may be in the form of a solid or 5 stranded sector cable. The tunnel 114 depicted has a generally rounded triangular-type section that is particularly suitable for crimping applications using triangular sector conductors, but is still effective for circular conductors. Whilst the tunnel 114 depicted extends through the length of both the second and third barrel portions 108, 109, it is envisaged that the tunnel 114 might be a blind tunnel extending only through the third 1o tunnel portion 109. The diameter of the third barrel portion 109 is larger than that of the second barrel portion 108. Specifically, the diameter of the third barrel portion 109 is 35.0mm in the arrangement depicted. A shoulder 115 is defined between the second and third barrel portions 108, 109. The diameter of the third barrel portion 109 is substantially equal to is the diameter of the first barrel portion 105. Accordingly, when the second barrel portion 108 is received in the cavity 106, the first and third barrel portions 105, 109 provide a substantially continuous cylindrical outer wall for application of a crimping tool as will be discussed below. To terminate an electrical conductor, an end section of the electrical conductor is 20 first stripped of any insulation in the usual manner so as to expose the core of the conductor. The bare end section of the electrical conductor is then inserted into the tunnel 114. A first crimp is then applied to the third barrel portion 109, at the position marked "A" in Figure 4, utilizing a standard hexagonal crimping tool, so as to deform the third barrel portion 109 to secure the bare end section of the electrical conductor within the 25 tunnel 114. This secures the second section 102 of the cable terminal lug 100 on the electrical conductor. The first section 101 of the electrical conductor 100 is then joined to the second section 102 by inserting the second barrel portion 108 within the cavity 106 formed in the first barrel portion 105. If desired, the first section 101 may be connected to the second section 102 prior to fitting the second section 102 to the electrical 30 conductor, including prior to supply of the cable terminal lug 100 such that the cable terminal lug 100 is supplied pre-assembled. With the first section 101 fitted to the second section 102, and the second section 102 secured to the electrical conductor, the first section 101 is rotated relative to the second section 102 as required to provide the desired orientation of the palm portion 103 6 for connection to a bus bar via the mounting aperture 104. A second crimp is then applied to the first barrel portion, at the location marked "B" in Figure 4, so as to deform the first barrel portion 105, securing it to the second barrel portion 108. The second crimp may extend over the junction between the first and third barrel portions 105, 109 as 5 indicated in Figure 4. If access permits, the second crimp may be applied after the palm portion 103 has been secured to a bus bar by way of a bolt passing through the mounting aperture 104. Persons skilled in the art will appreciate that various other modifications to the specific form of the cable terminal described above may be made.

Claims

1. A cable terminal lug comprising: an electrically conductive first section having a leading palm portion with a mounting aperture extending therethrough and a trailing first barrel portion, said first s barrel portion defining a substantially cylindrical cavity and being deformable by crimping; and an electrically conductive second section having a leading second barrel portion and a trailing third barrel portion coaxially extending from said second barrel portion, said second barrel portion being adapted to be received and retained in said cavity so as to 10 be rotatable within said cavity, said third barrel portion having a diameter greater than a diameter of said second barrel portion, said third barrel portion defining a tunnel for receipt of an electrical conductor, said second and third barrel portions being deformable by crimping.

2. The lug of claim 1, wherein said second barrel portion is adapted to be 15 retained in said cavity with an interference fit.

3. The lug of either one of claims I and 2, wherein said second barrel portion is adapted to be retained in said cavity by engagement of a protuberance formed on one of said second barrel portion and a wall of said cavity and an annular groove formed in the other of said second barrel portion and said wall of said cavity. 20

4. The lug of any one of claims 1 to 3, wherein said cavity is a blind cavity.

5. The lug of any one of claims I to 4, wherein said diameter of said third barrel portion is substantially equal to a diameter of said first barrel portion.

6. The lug of any one of claims I to 5, wherein an annular shoulder is 25 defined between said second barrel portion and said third barrel portion.

7. The lug of any one of claims 1 to 6, wherein said tunnel extends through both said second and third barrel portions.

8. A method of terminating an electrical conductor utilizing a cable terminal lug as defined in any one of claims I to 7, said method comprising the steps of: 30 (a) inserting a bare end section of an electrical conductor in said tunnel; (b) forming a first crimp on said third barrel portion to secure said bare end section of aid electrical conductor within said tunnel; (c) inserting said second barrel portion within said cavity; 8 (d) rotating said first section relative to said second section so as to locate said palm portion in a desired orientation; and (e) forming a second crimp on said first barrel portion so as to secure said second barrel portion within said cavity. 5

9. The method of claim 8, wherein step (c) is carried out prior to step (a).

10. The method of either one of claims 8 and 9, wherein said second crimp is formed on both said first and third barrel portions.

11. A cable terminal lug, substantially as hereinbefore described with reference to Figures 3 to 6 of the accompanying drawings. Dated 16 December, 2008 Cable Accessories (Australia) Pty Ltd Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON