GB2039148A - Electric contactor - Google Patents

Abstract

The moving contact plate 3 and axially movable shaft 1 in an electric contactor or motor starter are connected by a member 6 which comprises a base 7 mounted on the end 1c of the shaft 1 and having sides 10 which via notches 3a in the edges of the plate 3 hold the plate 3 parallel to the base 7 and arms 8 and 9 extending from the base 7 urge the plate 3 against the face 12 of the member 6 which is parallel to the base 7. Axial movement of the shaft 1 thus engages the plate 3 with fixed contacts 4 and 5 and resilient wings 14 extending outwardly from the face 12 of the member 6 engaging a stop surface 16 just before the plate 3 engages the fixed contacts 4, 5. The member 6 provides positive and aligned contact of the plate 3 with the fixed contacts 4, 5 whereas wings 14 provide a biassing force which ensures that contact is broken when the shaft 1 is retracted. <IMAGE>

Description

SPECIFICATION Electric contactor The present invention relates to improvements in the arrangement of the moving contactbearing shaft of the contactor of, for example, an electric starter.

Conventional contactors used for controlling the functioning of an electric starter for an internal combustion engine generally comprise a shaft whose free end engages, with clearance, in a contact plate which said shaft must apply against the two terminals of the circuit to be closed. Either a helical spring or a leaf spring is used for transmitting the bearing force from the shaft to the contact plate. This plate often jams with respect to the end of the shaft. In addition, as the heat conductivity is high between the plate which may heat up strongly and the shaft which is made of cast matter, an at least partial melting of the latter may occur.

Electro-magnetic contactors are known comprising elastic means for applying a contact against the terminals of the circuit to be closed or means for elastically returning the contact to its initial position. Such devices are found in German Patent Application No. 1 146 166, British Patent No. 1 482415 or U.S. Patent No. 2 897 311.

The object of the improvements according to the present invention is to remedy these drawbacks by providing an assembly which responds better than heretofore to the various desiderata of the art. To this end, a member is provided which is capable of performing the functions of guiding and holding a plate constituting the moving contact upon displacement of the moving element of the contactor without this plate being borne by the end of this element.

According to the invention, an elastic element or clip is associated with the end of the moving contact-bearing shaft of the contactor of an electric starter, which element comprises first means ensuring the holding of the moving contact, second elastic means adapted to apply this contact against the terminals of the circuit to be closed, and finally third means adapted elastically to return the moving element of the contactor to its rest position.

The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: Figure 1 is a partial view in section of an electric starter contactor comprising the improvements according to the invention.

Figure 2 is a view in perspective of the elastic element or clip which is associated with the end of the shaft.

Figure 3 is an exploded view showing, on the one hand, a variant embodiment of the elastic element shown in Fig. 2 and, on the other hand, the plate constituting the moving contact of the contactor.

Figure 4 is a view similar to that of Fig. 2, but showing a variant embodiment employing the elastic element of Fig 3.

Figure 5 is a view similar to that of Fig. 1, but in which the elastic element used is a variant of that shown in Fig 4.

Figure 6 illustrates, in perspective, a locking member used in the variant of Fig. 5.

Figure 7 is a view similar to that of Fig. 4, but showing another variant embodiment of the elastic element, the moving contact plate being shown in functioning position.

Figure 8 is a view in perspective of one of the parts of the elastic element illustrated in Fig. 7.

Referring now to the drawings, Fig. 1 shows the end of the shaft 1 of the contactor of an electric starter adapted to move in a core 2 and which is intended to apply a moving contact 3 in the form of a rectangular plate against the two terminals 4, 5 of an electric circuit which must be closed. The shaft 1 is made of plastics material so that the moving contact 3 is insulated with respect to the contactor assembly. This shaft is provided with a flange 1 a joined to its body by a truncated boss 1 b which cooperates in rest position with a depression 2a of the same shape made in the core 2. Beyond the flange 1 a, the shaft extends in an end piece 1 c.

The elastic element or clip 6 shown in Fig.

2 is composed of a thin base 7 which is generally square in form, slightly convex and provided with a central perforation 7a extending into radial slots 7b. It will be noted that the diameter of the perforation 7a is slightly smaller than that of the end piece 1 C of the shaft 1. Two of the opposite sides of the base 7 each extend by an oblique wing 8, 9 respectively, whose end 8a, 9a is turned back. The other two sides of the base 7 extend by a vertical side member 10, 11 followed by a face 12, 1 3 bent at 90 , i.e.

the two faces are in a plane parallel to that of the base 7. Progressively thinning oblique wings 14, 1 5 extend from the centre of each of the edges of faces 12, 13.

As shown in Fig. 1, the end piece 1 C of the shaft 1 is forcibly engaged in the perforation 7a of the base 7 which is thus fastened to said end piece. The plate 3 constituting the moving contact is provided with two notches 3a, 3b in which engages etch of the sides 10, 11 of the clip element 6 to ensure the guiding of the plate against which the two bent back ends 8a, 9a of wings 8, 9 rest, with the result that, at rest, this plate abuts against the two faces 12, 3 of the element 1. When the contactor is energized, the shaft 1 moves towards the right in Fig. 1 with a view to causing the plate 3 to cooperate with the terminals 4, 5.Just before the plate is in abutment against said terminals, the wings 14, 1 5 come against a fixed surface 1 6 of the contactor so that, at the end of stroke, i.e.

when the terminals 4 and 5 are connected by the plate 3, the wings 14 and 1 5 are taut so that they exert an antagonistic force against the shaft 1. This force enables said shaft to be returned to its initial position when the supply of the contact is eliminated.

Fig. 3 shows a variant embodiment of the elastic element 6. This latter is no longer a single piece, but it comprises two pieces 17, 18 respectively. The first comprises a square washer 1 9 pierced at its centre with a hole 1 9a of larger diameter than that of the end piece 1 C and of which two opposite sides extend in wings 8, 9 arranged in the clip element 6. The piece 1 8 comprises a base 20 which is strictly identical to the base 7 of the element 6, the base 20 being fast with sides 10, 11 and their respective extensions 12-14 and 13-15 which are also found in element 6.

The composite element is assembled as shown in Fig. 4, i.e. the element 1 7 is first fitted on the end piece 1 C of the shaft 1, then this end piece is engaged in the central hole of the piece 1 8 so that said latter is connected to the shaft, fastening the piece 1 7. The plate 3 constituting the moving contact is associated with the piece 1 8 in the same manner as it is with elastic element 6, and the functioning is identical to that described with reference to Fig. 1.

According to another variant illustrated in Fig. 5 and 6, the elastic wings 14, 1 5 are eliminated and their role is performed by a helical compression spring 21 of which one of the ends abuts against the surface 1 6 whilst its opposite end is centred with respect to a piece 22 illustrated in Fig. 6.

This piece 22 is identical to the one 1 8 shown in Figs. 3 and 4 except that its elastic wings 14, 1 5 are replaced by two lugs 22a, 22b adapted to effect the centering of the spring 21 by penetrating inside its turns.

As shown in Fig. 5, the piece 22 acts the same role of locking as the piece 1 8 as far as the fixing of piece 1 7 with respect to shaft 1 is concerned.

Fig. 7 shows another variant embodiment in which the piece 1 7 has been replaced by a pin 23 made of spring steel shown in Fig. 8.

This pin is in the form of an S with right angles, the two main arms of which 23a, 23b, are oblique with respect to each other.

Its central bar 23c is engaged in a slot 1 d in the end piece 1 C of the shaft 1 against the base of which it is held by the piece 1 8 described hereinabove with reference to Figs.

3 and 4.

The piece 1 8 could thus be replaced by the one referenced 22 on condition that it is associated with a spring 21 (Fig. 5).

The end piece 1 C of the shaft 1 could also comprise radial ribs adapted to cooperate with the slots 7b in the base 7 of the element 6 or in similar ones in the pieces 1 8 or 22 so as to immobilise them angularly with respect to the shaft 1.

An assembly is thus produced which enables the shaft to be shortened, the moving contact plate to be held so that it merges with the axis of the terminals without being subject to flexion, the strength of said plate to be increased as it does not comprise any perforation, and finally which avoids the heating of the plate in question damaging the shaft 1 made of plastics material, since it is not in contact with it.

Claims (9)

1. An element for connecting the shaft of the moving element of a contactor and the corresponding contact in the form of a plate which the shaft applies against fixed contacts via an elastic wing, wherein said connecting element comprises means for ensuring the guiding of the plate independently of the shaft.

2. An element as claimed in Claim 1, wherein the guiding means are constituted by an elastic element or clip comprising a base fixed to the end of the shaft and side members ensuring the guiding of the plate.

3. An element as claimed in Claim 2, wherein the base is convex and comprises a central hole extending into radial slots.

4. An element as claimed in Claim 3, wherein the end of the shaft comprises an end piece which engages in the hole of the base and ribs which enter in the radial slots therein.

5. An element as claimed in Claim 2, wherein the elastic element or clip is in one piece and has two wings whose ends abut against the plate and two ieaf springs which contact fixed stops for ensuring the return of the moving element to its initial position.

6. An element as claimed in Claim 2, wherein the base is associated with independent wings which cooperate with the plate.

7. An element as claimed in Claim 6, wherein the base is associated with elastic wings which return the moving element to its initial position.

8. An element as claimed in Claim 2, wherein the clip or elastic element is in one piece with two wings whose ends abut against the plate, whilst an independent helical spring ensures the return of the moving element into its initial position.

9. A connecting element substantially as described hereinabove and illustrated in the accompanying drawings.