GB2246241A - Switches - Google Patents

Abstract

A switch comprises at least one pole having a movable contact bridge for bridging fixed contacts, a monostable electromagnet having an armature for opening and closing the contacts via a slide 40, a spring biased lever 51 coupled to the slide 40 for urging the armature towards a rest position and a manually movable member 80 for holding the lever 51 against the return bias of its spring so as to hold the slide 40 in a contact closed position. <IMAGE>

Description

TITLE OF THE INVENTION Switching apparatus with contacts controllable by an electromagnet.

BACKGROUND OF THE INVENTION The present invention relates to an electromechanical switching apparatus whose contacts are controllable by an electromagnet.

Such apparatus are well known and they have a contactor function, if required, combined with a breaker function.

They comprise for example - at least one pole with separable contacts, - a magnetic trip and/or a thermal trip associated with said pole for controlling the opening of the contacts via a tripping mechanism, - at least one manual control button disposed on a front face of the case and acting on the tripping mechanism for opening and closing the contacts, - an electromagnet causing opening and closing of the contacts in response to the energization and to the deenergization of its coil, via a mobile assembly coupled to its armature, whereas a return system urges the armature towards a return position.

When the coil of the electromagnet is supplied with power; a holding current remains applied to this coil and the contacts of the apparatus remain in a stable closed or open state - unless an excess current fault has been detected by the tripping devices - until the supply to the coil is interrupted. The breaker apparatus thus operates in "contactor" mode.

It would be desirable to use the same apparatus for providing a "remote controlled breaker" mode control, i.e. with the coil at present fed with current pulses, the contacts of the apparatus should close and open alternately at each pulse, while remaining maintained in their position until the next pulse.

SUMMARY OF THE INVENTION The object of the present invention is to permit ready auxiliary manual control for closing the contacts of the switching apparatus by facilitating, as required, automatic return or locking of this control.

According to the invention, the electromagnet is of the monostable type having an armature urged by a return system and coupled to a mobile assembly capable of opening and closing the contacts, wherein - said return system comprises a pivoting lever urged by a spring and engaged with a bearing surface of a slider of the mobile assembly, - an auxiliary closure piece for the contacts is accessible through an opening in the front face of the apparatus, - the auxiliary closure piece cooperating with the pivoting lever and moving between an inactive position in which it releases said pivoting lever and an active position in which it locks said pivoting lever.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described hereafter by way of non limitative examples, with reference to the accompanying drawings, in which Figure 1 is a diagram illustrating a protective switching apparatus in accordance with the invention Figure 2 is a schematic elevational view of one embodiment of the protective switching apparatus Figure 3 is a top view of the apparatus of figure 2, the cover being removed, in partial section through II-II Figure 4 is a view of the front face of the apparatus in a first embodiment in the form of breakercontactor/remote controlled breaker Figures 5, 6 show schematically the mechanism for engaging the slider and the return system in respective open and closed positions of the contacts Figures 7, 8 show the respective positions of the button of the auxiliary closure piece ;; Figures 9, 10, 11 and 12, 13, 14 show in the same way as figures 4, 5, 6 and 7, 8 a second embodiment in the form of a breaker-contactor with lockable closure Figure 15 is a side view of a sub-assembly comprising the electromagnet, the mobile assembly, the return system and the engagement mechanism; Figures 16, 17 show the sub-assembly in elevation in the open and respectively closed positions of the contacts; Figure 18 is a view of the sub-assembly along arrow XI of Figure 17; Figures 19, 20, 21 show different positions of the bolt of the engagement mechanism; Figures 22, 23 show the bolt in a side view in the engagement position and respectively in the retracted position; and Figures 24, 25 show a variant of construction of the auxiliary closure piece.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The protective switching apparatus illustrated in Figures 1, 2 and 3 comprises a case > 10 formed of a base 11 and a cover 12. On the front face 12a of the cover are situated an ON button 13 and an OFF button 14. Opposite the front face 12a, the apparatus has a rear face lla adapted for fixing to a support.

The apparatus shown is bipolar, but may of course be unipolar, tri- or tetrapolar... Each pole comprises two power terminals 15, 16 with screws 15a, 16a each connected via a contact piece 17, 18 to a fixed contact 19, 20. The respective contacts 21, 22 of a contact bridge 23 cooperate with the fixed contacts so as to give rise to a double break.

The contact bridge 23 is connected to a contact holder 24. The contact holder is movable by a tripping mechanism 25 controlled. either manually by the ON 13 and OFF 14 buttons or automatically in response to an excess current by a magnetic trip 26 or a thermal trip 27 of the pole considered or of an adjacent pole.

The tripping mechanism 25 is housed in a compartment disposed transversely and orthogonally to the front 12a and rear ila faces of the apparatus. The contact bridge is mounted in the contact holder 24 by means of springs 28, the crushing of which, on closure, provides the contact pressure.

In addition, the contact bridge 23 is secured directly to a mobile assembly 30 coupled to an electric control electromagnet 31. Electromagnet 31 has a fixed magnetic circuit 32 and a mobile armature 33, as well as an energization coil 34 wound on a carcass which is mounted on a central leg of the magnetic circuit and of the armature. Screw terminals 34a are provided for supplying the coil with power. The electromagnet is of the monostable type, i.e. the armature can only be held against the fixed magnetic circuit by means of a holding current. A monostable electromagnet with plunger core could also be used.

The mobile armature 33 is coupled to a change of direction lever 35, one end 35a of which is mounted for pivoting and the other end 35b of which is connected to a slider 40 of the mobile assembly 30. Slider 40 is flat in shape and is adapted for sliding between the bent end of the contact piece 17 and the compartment of the tripping mechanism 25. Because of the lever, the slider travels over a distance which is a multiple of that of the armature.

Slider 40 is movable between a raised position in which it does not act on the contact bridges and a lowered position in which it causes the contact bridges to pivot.

A single break then occurs, by opening of contact 21, with pivoting of the contact bridge in the zone of contact 22.

The slider 40 has, in its lower part, a central leg 41 (see figure 15) into a slit of which one end of lever 34 penetrates and lateral fingers 42, 43 in number equal to that of the poles and each of which cooperates with a contact bridge of a respective pole.

A return system 50 and an engagement mechanism 60 are associated with slider 40.

The return system 50 comprises a cranked pivoting lever 51 mounted on a fixed shaft 52 and in engagement through a circular or obiong orifice provided at its lower end with a tenon 44 situated at the upper part of slider 40. At a point 53 situated at its upper end, lever 51 is urged in an anti-clockwise direction by a spring 54 anchored to a fixed point 55. The position and the characteristics of elements 50-55 are determined so that the return system urges slider 40 with a force which decreases with closure of armature 33 of the magnetic circuit, i.e. which decreases when the contacts close and impact. It should be noted that the force of the contact pressure springs also decreases during closing of the armature.

This negative slope return system has the advantage of appreciably reducing the energy to be expended for closing the contacts.

The engagement mechanism 60 is of the follower type and has a pivoting bolt 61 mounted on a pivot 62 and urged by a spring 63 in a clockwise direction (Figures 5, 6; 10, 11 and 15). Bolt 61 is designed for receiving in a housing 64 a pin 45 belonging to slider 40. Ramps 66a, 66b operating when the slider moves up and a transverse ramp 67 operating when the slider moves down are provided on bolt 61. The latter is a stamped and bent part.

Bolt 61 may be slanted transversely so as to let the slider pass freely (see Figures 22, 23). The bolt pivots then about an axis orthogonal to that of the pivot and against a resilient force provided by a helical part of spring 63 or by any other spring. The driving force for the pivoting movement is either pin 45 when it is situated in housing 64 and when the slider moves down (see Figure 22; broken line position) or a pivoting switch 70 with cam 71 which passes through an opening 12b in the front face 12a of the case (see Figure 23). Switch 70 may be actuated by a tool for occupying two positions, indicated by C (contactor) and T (remote controlled breaker) in Figure 4.

In position T of Figure 22, which corresponds to Figures 5, 6, cam 71 does not urge the bolt 61. In position C, which corresponds to Figure 23, cam 71 pushes bolt 61 back.

As can be seen in Figures 4 to 8, a manual auxiliary closure piece 80 is provided having a button or grip 81 accessible through an opening 12c in the front face 12a of the case of the apparatus. In the present example, the piece is mounted for sliding between a rest position (Figure 5) and a working position (Figure 6). When piece 80 is moved manually from its rest position to its working position it causes pivoting lever 51 to pivot in a clockwise direction by means of a pin 82 or a ramp cooperating with an element or a bearing surface such as the head 56 of lever 51. In order to hold lever 51 pivoted against the force of spring 54, piece 80 has a retaining surface 83 for head 56. Notches and projections 84 are formed in piece 80 and in the case for holding the manual closure piece 80 in its rest and working positions. Piece 80 is guided by slides such as 85.

In the embodiment illustrated in Figures 9, 10, 11 and 12, 13, no engagement mechanism 60 or switch 70 is provided, which means that the electric control of the apparatus will always be in "contactor" mode, i.e. closure of the contacts will only be maintained by supplying the coil with a holding current.

The manual auxiliary closure piece is urged to its rest position by a spring 86, and its button 81 is capped by a cursor 87, whereas the opening 12c of the case has, at its left hand end, a step 12d. Cursor 87 may slide over button 81 perpendicularly to the direction of movement of piece 80 and engage in the step for locking the piece in its working position shown in Figure 11 which corresponds to closing of the contacts. In the position shown in Figures 10 and 12, piece 80 is at rest and slider 40 may then freely move up and down depending on whether the coil is supplied with power or not.In the position shown in Figures 11 and 13, piece 80 has been placed in "manual operation" but it is not locked and. as soon as the electromagnet is supplied with power again, piece 80 escapes from the pressure of the pivoting lever and comes back to its rest position shown in Figure 10 under the effect of spring 86. In the position shown in Figures 11 and 14, piece 80 is placed in "manual operation", but it is locked in this active position, and the contacts of the apparatus can only be opened - apart from a magnetic or thermal fault - by the voluntary return of cursor 87 over button 81. It goes without saying that all other elements for blocking or locking button 81 may be used instead of those which have been described.

Figures 15 to 18 illustrate the sub-assembly formed of the electromagnet 31, slider 40, the associated return system 50 and the engagement mechanism 60. The different parts of the sub-assembly are mounted on an insulating support 90 which forms the carcass of the coil, the fixed bearing point of spring 54, the shaft of bolt 61, etc...

Figures 19, 20, 21 show different positions of bolt 61.

Figure 19 shows the beginning of lifting of slider 40; the bolt is urged in -a clockwise direction by spring 63. It is pushed back in an anti-clockwise direction towards the position shown with broken lines when pin 45 (position 1) is applied on the lower ramp 66a, and then jumps on to the upper ramp 66b (position 2) and comes rapidly back to position 3 then 4 before engagement in housing 64. The slider is then held in a raised position - and the contacts closed - until the next current pulse applied to the coil. In this case, pin 45 passes from position 4 to position 5 and spring 63 brings the bolt back in a clockwise direction to the position shown in Figure 21 in which pin 45 is allowed to move down by ramp 67.The engagement mechanism described may of course be replaced by any other equivalent mechanism conferring on the electromagnetic control sub-assembly a bistable character with simplicity and in a small space.

Figure 22 shows pivoting of the bolt to the position shown with broken lines under the effect of pin 45 when the latter passes from position 7 to position 8. Figure 23 shows the bolt slanted by rotation of the manual switch 70 placed in its position T. Spring 63 causes the bolt to come back to its vertical position.

In the variant shown in Figures 24, 25, the "contactorremote controlled breaker" mode switch is a slider 91 movable manually or by a tool through an opening 12e from a position in which it makes the bolt 61 inactive (figure 24) by bearing on a heel 92 of the bolt to a position in which it allows bolt 61 to operate (figure 25). In addition, the pivoting lever 51 has a projection 57 with a slit in which a tool may be engaged after passing through an opening 12f for causing manual closure (or in some cases opening) of the contacts.

The invention has been described for a breaker apparatus with contactor function. It is of course applicable to any apparatus of the contactor kind, with monostable electromagnet.

Claims (6)

WHAT IS CLAIMED IS

1. An electromagnet switching apparatus comprising in a case - at least one pole with mobile contact bridge cooperating with fixed contacts, - a monostable type electromagnet having an armature urged by a return system and coupled to a mobile assembly capable of opening and closing said contacts, wherein - said return system comprises a pivoting lever urged by a spring and engaged with a bearing surface of a slider of said mobile assembly, - an auxiliary closure piece for the contacts is accessible through an opening in the front face of the apparatus, - the auxiliary closure piece cooperating with the pivoting lever and moving between an inactive position in which it releases said pivoting lever and an active position in which it locks said pivoting lever.

2. The apparatus as claimed in claim 1, wherein said pivoting lever is held locked by the direct application of a bearing surface of the lever on said auxiliary closure piece under the effect of the spring of said return system.

3. The apparatus as claimed in claim 1, wherein said auxiliary closure piece is urged by a return spring towards its inactive position.

4. The apparatus as claimed in claim 1, wherein said auxiliary closure piece is lockable in its active position.

5. The apparatus as claimed in claim 4, wherein said auxiliary closure piece has a manual grip with a cursor movable for housing in a step formed in the opening of the case.

6. An electromagnetic switching apparatus, as claimed in claim 1, substantially as described herein with reference te the figures of the accompanying drawings.