GB2037503A

GB2037503A - Electrical Terminals

Info

Publication number: GB2037503A
Application number: GB7939947A
Authority: GB
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1978-12-07
Filing date: 1979-11-19
Publication date: 1980-07-09
Also published as: GB2037503B

Abstract

An electrical terminal for terminating a stranded aluminium conductor, comprises two relatively rotatable parts 1, 10, part 10 serving as a compression member operative to reduce the cross-sectional area of a passage 5 in the part 1, in which passage the conductor is received. The passage 5 is defined by opposed spaced arms 3 defining at the open end an outer oval cross- section. The compression part 10 has an oval hole 11. The part 10 is placed over the arms 3 and is rotatable relative to the longitudinal axis of the passage 5 so that the wall of hole 11 urges the arms 3 towards one another. <IMAGE>

Description

SPECIFICATION Electrical Terminal This invention relates to an electrical terminal, and particularly to an electrical terminal for terminating a multi-strand aluminium conductor as used in electricity supply systems.

According to this invention, an electrical terminal comprises a body member of electrically conductive material having a base and a pair of parallel spaced arms extending in the same direction from the base, inner surfaces of the arms defining a circular cross-section passage between them, and the arms defining an oval cross-section with their outer surfaces, the arms being spaced from each other in the direction of the major axis of the oval cross-section defined by the outer surfaces of the arms; and a compression member of electrically conductive material having an oval cross-section hole therein, through which hole the arms of the body member are received, the compression member being rotatable relative to the arms about the longitudinal axis of the passage defined by the arms, from a first position in which the major axis of the hole coincides with the major axis of the oval cross-section defined by the outer surfaces of the arms, and the arms are relatively spaced, to a second position in which the major axis of the hole coincides with the minor axis of the oval cross-section defined by the outer surfaces of the arms, and the arms are urged towards each other by engagement of the arms with the wall of the hole, thereby to reduce the cross-sectional area of the passage defined by the arms.

For use of the terminal of this invention, with the compression member in the first position on the arms of the body member, a multi-strand aluminium conductor, or another conductor, of substantially the same diameter as the passage defined by the arms, is inserted into the passage, and the compression member is then rotated relative to the arms to the second position. During such rotation of the compression member, the arms are urged towards each other, the crosssectional area of the passage being reduced, and the arms being urged into intimate contact with the conductor in the passage. The conductor is thereby deformed and a good electrical connection is established between the terminal and the conductor.Further, frictional forces act between the conductor and the compression member during rotation thereof, which forces break up any undesirable, for example oxide, films on the conductor.

An electrical terminal according to this invention will now be described by way of example with reference to the drawings, in which: Figure 1 is a plan view of a body member of the terminal; Figure 2 is a longitudinal section through the body member of Figure 1; Figure 3 is a view in the direction of the arrow Ill in Figure 1; Figure 4 is a longitudinal section through a compression member of the terminal; Figure 5 is a view in the direction of the arrow V in Figure 4; Figure 6 is a view in the direction of the arrow VI in Figure 4; Figure 7 is a longitudinal section through the compression member of Figure 4 at right-angles to the section of Figure 4; Figure 8 is a plan view of the assembled terminal; and Figure 9 is a longitudinal section through the terminal of Figure 8.

The body member 1 shown in Figures 1 to 3, is an aluminium casting, and comprises a base 2 having a pair of parallel spaced arms 3 extending in the same direction from one surface of the base 2. The inner surfaces of the arms 3 are provided with longitudinally extending serrations 4, and are concave and define between them a circular cross-section passage 5 having an outwardly flared mouth 5a. The outer surfaces 6 of the arms 3 have first portions 6a adjacent their free ends, which together define an oval cross-section (best seen in Figure 3), and second inner portions 6b which together define a circular cross-section, the arms 3 being spaced from each other in the direction of the major axis of the oval crosssection.

Extending from the opposite surface of the base 2 to the arms 3 is a rectangular coupling plate 8 having a hole 9 therein whereby the terminal can be connected to electrical equipment by means of a bolt passing through the hole 9.

The compression member 10 shown in Figures 4 to 7 is of steel, and has a hexagonal outside cross-section for engagement by a spanner over part 1 Oa of its length, and a circular outside crosssection over the remainder 1 Ob of its length.

Within the hexagonal cross-section portion 1 Oa of the compression member 10 is an oval crosssection hole 1 while the remainder 1 Ob has an axially aligned circular cross-section hole 12 therein. On the end (right-hand end in Figure 4) adjacent the circular cross-section hole 12, the compression member 10 has a part-annular projection 13 extending over 900 of arc including one end of each of the major and minor axes of the oval hole 1 This projection 13 is, in the assembled state of the terminal, received in a 1800 recess 14 (Figures 1 and 9) formed in the base 2 of the body member 1.

Referring now to Figures 8 and 9, in the assembled state of the terminal the arms 3 of the body member 1 are received in the holes 11 and 12 in the compression member 10, with the hole 11 adjacent the free ends of the arms 3.

When the major axis of the oval hole 11 in the compression member 10 is aligned with the major axis of the underlying oval cross-section portion 6a defined by the outer surfaces 6 of the arms 3, the arms 3 are spaced apart as shown in Figures 2, 3 and 9. With the compression member 10 in this first position relative to the body member 1, a multi-strand conductor (not shown) having a cross-sectional area substantially equal to that of the then circular-cross section passage 5 between the arms 3, can be inserted into the passage 5, the flared mouth 5a facilitating such insertion.

The compression member 10 is then rotated about the arms 3 by means of a spanner engaged with the hexagonal portion 1 Oa until the major axis of the oval hole 11 in the compression member 10 has turned through 900, this rotation being limited by engagement of an end of the projection 1 3 with an end of the recess 14 in the body member 1. During such rotation, the arms 3 are urged towards each other by engagement of the outer surfaces 6 of the arms 3 with the surface of the oval hole 11, and the original major axis of the oval cross-section portion 6a defined by the outer surfaces 6 of the arms 3 is shortened to substantially the length of the minor axis of this oval cross-section.

The serrations 4 on the arms 3 are thus urged into intimate engagement with the conductor in the passage 5, and the conductor is deformed out of its original circular cross-section as the crosssectional area of the passage 5 is reduced.

A good electrical and mechanical connection is thereby established between the terminal and the conductor, and the terminal can be used to connect the conductor to electrical equipment by means of a bolt (not shown) passing through the hole 9 in the plate 8 of the terminal.

Claims

1. An electrical terminal comprising a body member of electrically conductive material having a base and a pair of parallel spaced arms extending in the same direction from the base, inner surfaces of the arms defining a circular cross-section passage between them, and the arms defining an oval cross-section with their outer surfaces, the arms being spaced from each other in the direction of the major axis of the oval cross-section defined by the outer surfaces of the arms; and a compression member of electrically conductive material having an oval cross-section hole therein, through which hole the arms of the body member are received, the compression member being rotatable relative to the arms about the longitudinal axis of the passage defined by the arms, from a first position in which the major axis of hole coincides with the major axis of the oval cross-section defined by the outer surfaces of the arms, and the arms are relatively spaced, to a second position in which the major axis of the hole coincides with the minor axis of the oval cross-section defined by the outer surfaces of the arms, and the arms are urged towards each other by engagement of the arms with the wall of the hole, thereby to reduce the cross-sectional area of the passage defined by the arms.

2. A terminal as claimed in Claim 1, in which the compression member has a first portion containing the oval cross-section hole, and a second portion having an axially aligned circular cross-section hole therein through which the arms of the body member are received.

3. A terminal as claimed in Claim 1 or Claim 2, in which one end of the compression member is formed with a part-annular projection on the end face, which projection extends over 900 of arc including one end of each of the major and minor axes of the oval hole in the compression member, the projection being received in a 1 800 recess in the body member thereby to limit rotation of the compression member relative to the arms of the body member.

4. A terminal as claimed in Claim 2 or Claim 3, in which the first portion of the compression member has a hexagonal outside cross-section.

5. A terminal as claimed in any preceding claim, in which the body member includes a coupling plate with a hole therein extending from a surface of the base opposite to a surface from which the arms extend.

6. A terminal as claimed in any preceding claim, in which the hole in the compression member is formed with longitudinally extending serrations.

7. An electrical terminal substantially as hereinbefore described with reference to, and as shown in, the drawings.