GB2057794A

GB2057794A - Connection terminal for electrical apparatus

Info

Publication number: GB2057794A
Application number: GB8028048A
Authority: GB
Original assignee: Societe dAppareillage Electrique SAPAREL SA
Current assignee: Societe dAppareillage Electrique SAPAREL SA
Priority date: 1979-09-05
Filing date: 1980-08-29
Publication date: 1981-04-01
Also published as: MA18946A1; IT8068368A0; GB2057794B; BE884776A; PT71761A; AR223391A1; PT71761B; IT1129146B; FR2464570A1; FR2464570B1

Abstract

An electrical connection terminal comprises connection part (6) of electrically conductive strip material having a curved-over end (7) engaging a pin (8), and a U-shaped stirrup piece (1) pivotally mounted on the pin, the stirrup piece having two flanges (4, 5) connected together by a web (2), with those ends of the flanges that are distant from the web being arranged at respective sides of the curved-over end and being provided with respective holes through which the pin is engaged, and the web having a tapped hole through which a screw (3) is screwed for clamping a conductor (13) against the curved- over end of the connection part. Rotation A, B of the stirrup piece (1) relative to the connection part (6) allows the conductor (13) to approach the terminal from any direction in an arc of at least 270 degrees. <IMAGE>

Description

SPECIFICATION Connection terminal for electrical apparatus The invention relates to connecting electrical cables to electrical apparatus, in particular to electrical apparatus whose terminals are inclined to comply with certain standards. In this connection, it is sometimes required that the terminals of mains electricity circuit breakers on customer premises be disposed so that the contact surface is inclined at an angle between 30 and 45 to the vertical plane on which the apparatus is mounted. This requirement, which was established at a given period of technological development, has subsequently been found to be detrimental, since ease of connection depends not only on the inclination of the terminal but also on the layout of the apparatus and, in particular on the diameter of the cable to be connected.

Generally, any given input direction of the cable to the apparatus as a whole defines a preferred terminal orientation for easy insertion of the cable conductor into the terminal.

Further, the larger the cable diameter, the stiffer the cable and therefore the larger its minimum radius of curvature, which means that bending today's higher current cables to meet the old standard terminal inclination is more difficult than it used to be and takes up more space. Hence, a connection terminal with a fixed orientation facilitates one particular connection configuration to the detriment of all others, which gives rise to cabling difficulties in practice. This state of affairs obliges manufacturers to provide a range of apparatus that differ only in their terminals which vary to suit different types of connection to be made. This is quite obviously an economic disadvantage.

Preferred embodiments of the present invention remedy these drawbacks by providing a terminal for connecting a cable whose end can be orientated within a range of at least 270 > relative to said terminal.

The present invention provides an electrical connection terminal comprising a connection part of electrically conductive strip material having a curved-over end engaging a pin and a U-shaped stirrup piece pivotally mounted on the pin, the stirrup piece having two flanges connected together by a web, with those ends of the flanges that are distant from the web being arranged at respective sides of the curved-over end and being provided with respective holes through which the pin is engaged, and the web having a tapped hole through which a screw is screwed for clamping a conductor against the curved-over end of the connection part.

The invention will be better understood from the following description of examples thereof illustrated in the accompanying drawings in which: Figure 1 illustrates a terminal in accordance with the invention; Figures 2, 3, 4, 5 and 6 show various possible orientations of a cable relative to a terminal as illustrated in Fig. 1; Figure 7 illustrates a variant of the terminal's connection part illustrated in Fig. 1; Figure 8 shows how a terminal is fitted into an insulating support; Figure 9 illustrates a variant of a terminal in accordance with the invention; Figure 10 illustrates a variant of the connection part of the terminal of Fig. 9; and Figure 11 illustrates an example of application of a terminal as illustrated in Fig. 1 in connection with an electrical apparatus.

Fig. 1 illustrates a terminal which embodies the invention. The top of a U-shaped stirrup piece 1 has a tapped hole 2 in which a screw 3 is inserted. Each of two flanges 4 and 5 of the stirrup piece has a hole 9 at its end. The flanges engage on either side of a connection part 6 made from a strip of metal which is a good conductor of electricity. A curved-over end 7 of the connection part form a cylinder.

A pin 8 which passes through the holes 9 in the flanges is inserted through said cylinder.

The pin has a head 10 at one end and the other end is, for example, either flattened after installation, to make it impossible to separate the pin and the stirrup piece, or else it is threaded to receive a nut or, even, has a hole to receive a cotter pin.

Another portion 1 2 of the connection part 6 serves to fix said connection part on equipment; and the portion 1 2 including the other end of the connection part. The connection part 6 includes an intermediate portion 14 extending between the curved-over end 7. In Fig. 1, the portions 14 and 12 form an angle to facilitate assembly of the terminal on the equipment and to allow a cable to be orientated in any direction relative to the terminal.

When the screw 3 is loose, the stirrup piece 1 can be tilted in the direction of the arrow A or in the direction of the arrow B. In practice this makes it possible for the stirrup piece to rotate through at least 180 about the pin and therefore to connect cable ends whose orientation can be varied by at least 270 relative to the curved over end 7, as shown in Figs. 2 to 6, thereby allowing a high degree of flexibility in the connection.

One end 1 3 of a cable C constituted by bared end of a covered conductor is engaged between the curved over end 7 of the connection part and the screw 3. By tightening the screw, the cable end is held fast between the end 11 of the screw and the curved over end 7.

Dashed lines in Fig. 1 illustrate the stirrup piece 1 in the horizontal position in which the torque applied to the ends of the pin 8 during tightening of the screw 3 tends to deform the curved-over end 7 in the direction shown by an arrow e (there being an equal and opposite reaction at the other end of the pin 8). When the stirrup piece is in the vertical position, the torque applied to the ends of the pin 8 during tightening of the screw extends a couple on the connection part 6 which tends to twist; an arrow fshows the direction of a force on the visible end of the pin 8. To overcome these disadvantages, the connection part 6 may be built with larger dimensions than necessary for the intensity of the current which it is intended to pass. These larger dimensions are made even more necessary by the fact that a low current passes through the connection part 6.This is economically rather unsatisfactory, since the connection part 6 is made of a metal which is a good conductor of electricity, e.g. copper which is an expensive metal and which is mechanically not very strong.

Another solution consists in reinforcing the connection 6 with a reinforced part made of a metal which is not necessarily a good conductor of electricity but is mechanically strong, as shown in Fig. 7.

Figs. 2 to 6 illustrate various orientations of a cable C relative to the terminal illustrated in Fig. 1. In Fig. 2, the end of the cable C points downwards; Figs. 3 and 4 are derived from Fig. 2 by rotation of the cable and of the stirrup piece to the left; Figs. 2, 3, 4 show that the orientation of the cable end can vary by 180 relative to the connection part 6. In Fig. 5, the cable is horizontal, but its orientation is the opposite of that in Fig. 3; Fig. 6 is derived from Fig. 5 by rotating the cable C and the stirrup piece to the left, the orientation of the cable in Figs. 6 being the opposite of that in Fig. 4; Figs. 5 and 6 show that the orientation of the cable C relative to the connection part 6 can vary by at least 90 .

Therefore, as illustrated in Figs. 2 to 6, the orientation of a cable end relative to the connection 6 can vary through a wide range, i.e. at least 270 ; this makes it possible to use the terminal in accordance with the invention in practically all cases since it is obvious that it is always possible to bend the cable in such a way that its end is orientated within the aforementioned range of 270 .

Fig. 7 illustrates a variant of the connection part 6 illustrated in Fig. 1. In Fig. 7, where, for clearness' sake the pin 8 and the stirrup piece 1 are not shown, a connection part 1 5 includes a reinforcing piece 16 to avoid the deformation which could be caused when tightening the screw on the conductor, as previously stated. Reinforcing piece 16 which is mechanically strong but is not necessarily made of a metal which is a good conductor of electricity, is applied against the connection part 1 5 from a notch 18 in the semi-cylindrically curved end portion 1 7 thereof, to that end 1 2 of the connection part 1 5 which is bent relative to the part 14.The reinforcing piece 1 6 has a tab 1 9 which ends in a tooth 20 which fits into the notch 1 8. The tab 1 9 provides a space between it and the curved end 17, the pin 8 being inserted in said space.On each side of its portion in contact with the portion 1 4 of the connection part, the reinforcing part 1 6 has a portion such as 21 that is folded over the portion 1 4 so as to make the connection part 1 5 fast with the reinforcing part 1 6. The reinforcing part 1 6 further has, on each side of the end 1 2 of the connection part, a folded rim 22 of height equal, at the most, to the thickness of the connection part; these rims guide the connection part when the reinforcing part is installed.

Said reinforcing part prevents the connection part 1 5 from twisting when the stirrup piece is in the vertical position, as shown; when the stirrup piece is in the horizontal position, the force transmitted by the pin is exerted on the tab 1 9 of the reinforcing part and not on the curved end 1 7 of the connection part, which is therefore not deformed. In both cases, the force is therefore borne by reinforcing part which does not need to be very thick since it is made of rigid metal; therefore, it is not necessary to have a connection part 1 5 of large size. Of course, the end 1 2 of the connection part 1 5 may be in line with the portion 14, the reinforcing part 1 6 then being plane.

The furthest end of the reinforcing part 1 6 from the tab 1 9 may also include a positioning tooth 23 for fastening the terminal in some cases of assembly as illustrated in Fig.

8.

Fig. 8 is a side view of a terminal such as shown in Fig. 7 assembled in an insulating support 24; a slot 25 in the insulating support makes it possible to engage the connection part 1 5 with the reinforcing part in the insulating support, while the positioning tooth 23 traps the terminal and prevents it from moving in a direction perpendicular to the slot. The dimensions of the insulating support 24 must be sufficient for it to withstand forces transmitted by the pin 8 when the cable is clamped, such forces being borne by the connection part 1 5 and the reinforcing part 1 6 and being transmitted thereby to the insulating support.

Of course, the end 12 of the connection part 15, Fig. 7, can be fixed by any known means to an electric apparatus and the positioning tooth need not be used.

In Fig. 9, which illustrates a variant of a terminal in accordance with the invention, a connection part 26 has a straight portion 27, a semi-cylindrical curved portion 28 and a plane portion 29 ending in a bent portion 30 which comes into contact with the straight portion 27; the end of the connection part is therefore shaped like a button-hole in which the pin 8 of the stirrup piece 1 can move and the stirrup piece can turn about the pin 8 to allow a cable to be connected either to the plane portion 29 or to the curved portion 28 or, even, to the straight portion 27. Since the pin 8 can move, it is possible to clamp the cable at any point on the straight portion 27 or on the plane portion 29.The Figure shows a second stirrup piece 31 for connecting a second conductor on the straight portion 27 independently from the stirrup piece 1 which could obviously be assembled symmetrically so as to allow a conductor to be connected on the plane portion 29. When there are two stirrup pieces, a single stirrup piece only, e.g.

1, need turn about the pin 8; however, in some cases, it is very useful to install a second stirrup piece, in particular when the number of cables to be installed is such that a single stirrup piece is insufficient. In such a variant, the connection part must have dimensions which enable it to withstand the torsion forces which occur when the stirrup piece is used to clamp a cable on the curved portion 28. Torsion forces can also be avoided by reinforcing the connection part 26.

Fig. 10 illustrates the connection part 26 of Fig. 9, equipped with a plane, mechanically rigid metal reinforcing part 32 assembled on the side nearest the straight portion 27. Each side of the reinforcing part has a rim such as 33 which is folded over the straight portion 27 between the bent portion 30 and the curved portion 28; it also includes a guide 34 on each side of the straight portion 27.

Such a connection part equipped with a reinforcing part, can be used for connecting a cable only in its curved portion 28 and in its plane portion 29.

Fig. 11 illustrates an example of the use of a terminal embodying the invention in a modular circuit-breaker which includes two insulating parts 35 and 36 forming a housing and a cover and each including a respective flap 37 and 38. One connection 6 is fixed to the modular circuit breaker by its end 1 2 and includes a stirrup piece 1; for example, each end of the pin 8 is recessed through half the thickness of the flaps 37 and 38 to make it impossible to lose the pin. One of the flaps 38 of the insulating parts includes notches such as 39, one flange of the stirrup piece includes a resilient finger 40 which fits into one of the notches and keeps the stirrup piece in a determined position. The figure shows the stirrup piece 1 covered with an insulating part 41 made of a plastics material, for example, and whose upper portion has a hollow cylinder 42 in which the screw 3 moves. The assembly formed by the insulating part 41 is larger than the stirrup piece, the height of the hollow cylinder being greater than the length of the screw 3 so that it does not extend beyond said cylinder when completely unscrewed. Therefore, the insulating part 41 insulates the stirrup piece 1 to comply with standards which require terminals to be insulated to make it impossible to bridge them together accidentally by the handles of pliers, non-insulated screw-drivers, conducting rods or the like.

Claims

1. An electrical connection terminal comprising a connection part of electrically conductive strip material having a curved-over end engaging a pin and a U-shaped stirrup piece pivotally mounted on the pin, the stirrup piece having two flanges connected together by a wab, with those ends of the flanges that are distant from the web being arranged at respective sides of the curved over end and being provided with respective holes through which the pin is engaged, and the web having a tapped hole through which a screw is screwed for clamping a conductor against the curved-over end of the connection part.

2. A connection terminal according to claim 1, wherein the curved-over end of the connection part forms a cylinder in which the pin is engaged.

3. A connection terminal according to claim 1, wherein the curved-over end of the connection part is in the form of a halfcylinder and has a notch, wherein a mechanically rigid metal reinforcing part is placed against the connection part, on the end nearest the curved-over portion thereof, and includes two portions folded over the connection part to make it fast with the reinforcing part and wherein the reinforcing part includes a tab which ends in a tooth fitting in the notch and providing a space in which to fit the pin.

4. A connection terminal according to claim 1, wherein the curved-over end of the connection part is shaped like a button hole and has two flat portions joined together by a semi-cylindrical curved portion.

5. A connection terminal acoording to claim 4, wherein the connection part includes a mechanically rigid metal reinforcing part with two rims folded back inside the button hole so as to make the connection part fast with the reinforcing part.

6. A connection terminal according to claim 4 or 5, including two stirrup pieces whose pins engage in the button hole.

7. A connection terminal according to any preceding claim, wherein the stirrup piece is covered by an insulating part which includes a hollow cylinder in which the screw can be inserted, the height of said cylinder being at least equal to the length of the screw.

8. A connection terminal according to any preceding claim, wherein one flange of the stirrup piece bears a resilient finger to position the stirrup piece when the terminal is used in an electric apparatus provided with notches, said resilient finger fitting into one of said notches.

9. An electric connection terminal substantially as herein described with reference to and as illustrated in the accompanying drawings.