GB2236618A

GB2236618A - Electromagnetic switches

Info

Publication number: GB2236618A
Application number: GB9021260A
Authority: GB
Inventors: Patrick Larcher; Pierre Merlin
Original assignee: La Telemecanique Electrique SA; Telemecanique SA
Current assignee: Telemecanique SA
Priority date: 1989-10-06
Filing date: 1990-10-01
Publication date: 1991-04-10
Anticipated expiration: 2010-10-01
Also published as: DE4030212C2; DE4030212A1; GB9021260D0; IT9021532A1; IT9021532A0; ES2024323A6; ATA194590A; FR2652947A1; GB2236618B; FR2652947B1; CH683468A5; IT1243025B; AT404522B

Abstract

An electromagnetic switch comprises, in a case, an electromagnet whose armature (25) is connected to a movable contact holder (16) having a row of recesses (34) housing a movable normally closed contact bridge (PR) urged by a spring (2). The recesses (34) have a U shape covered by a plate (39) mounted fixedly in the case between the armature (25) and contact holder (16) so as to form a fixed support for each contact spring 2 housed in a recess (34). The plate (39) has apertures (40) to allow passage of the contact holder (16) when the electromagnetic coil (22) is energised to open the contacts. The arrangement allows a single return spring to be used for the armature (25), whatever the arrangement of the contacts associated with the contact holder. <IMAGE>

Description

::---:Z---:2- CC 1 a Electromagnetic control apparatus with opening poles

The present invention relates to a switching apparatus with electromagnetic control of the contactw 5 kind, comprising in a case - an electromagnet formed of an energization coil and a magnetic circuit comprising a fixed armature and a mobile armature urged by a return spring; - a plurality of opening poles each having a bridge of 10 mobile contacts cooperating with fixed contacts; - a contact holder block having a row of parallel identical recesses, in number equal to or greater than the number of opening poles, in which are engaged the mobile contact bridges each slaved to a contact pressure spring, the contact holder being fast with the mobile armature of the electromagnet and being movable in translation between a rest position in which the contacts are normally closed and e working position in which the contacts open through attraction of the mobile armature by the fixed armature at the time of energization of the coil.

Such an apparatus with several opening poles, for example four in number, is described in the patent FR - 1 523 839. According to this patent, the recesses of the contact holder have a rectangular shape and, for each opening pole, house an auxiliary piece which is fixed with respect to the case and on which one of the ends of the contact pressure spring is applied, the other end of said spring being applied on the mobile contact bridge. The purpose of these auxiliary pieces is to form fixed supports for the associated contact pressure springs and so to set the contact bridges so as to annihilate, at the start of movement of the contact holder actuated by the electromagnet and before opening of the contacts, the resistant forces due to the contact pressure springs.

However, these auxiliary individual pieces, in number equal to the number of opening poles, are generally 2 mounted manually one by one in the recesses of the contact h-older, whence -- a relatively long overall assembly time. In addition, assembly of the auxiliary pieces as well as that of the contact pressure springs and of the mobile contact bridges in rectangular shaped housings each time forms a particularly difficult operation to carry out.

The purpose of the invention is to overcome these drawbacks and to provide a switch with several opening poles of the above recalled type by equipping it with the same part of simple structure which is common to all the opening poles so as to serve as fixed support for the contact pressure springs associated with the mobile opening contac, bridgey and which, because of its design and that of the contact holder, makes ready mounting possible, capable of being automated, of the opening contact bridges and their respective springs in tne recesses of the contact holder.

According to the inventic.,i, an electromagnetically controlled switching apparatus of the above described type is particularly characterized in that:

- the recesses of the contact holder are in the form of a U opening outwardly, on the mobile armature side of the electromagnet, these Ushaped recesses forming insulating walls therebetween; - a plate for setting the mobile contact bridges is inserted between the contact holder and the mobile armature of the electromagnet, so as to cap the U-shaped recesses of the contact holder, this plate being mounted fixedly in the case so as to form a f ixed suppc.ct for the contact pressure springs housed in the recesses and placed as support for the associated mobile contact br% _jes, and being pierced with cavities for the passage of the -.. _sulating walls of the contact holder during movement thereof, which contact holder is connected to the mobile armature of the electromagnet by appropriate assembly means.

Other features and advantages of the invention will be clear from the following detailed description with reference to the accompanying drawings given solely by way of example and in which:

Figure 1 is a perspective view of the case of a 5 multi-pole contactor according to the invention; Figure 2 is an exploded perspective view, after removal of the lid pf the case, of the components of the contactor; Figure 3 is a schematic view in front elevation of a contactor in the rest position, a closure pole being shown with broken lines; Figure 4 is a lateral elevational view of the contact holder/electromagnet assembly in the rest position of the contactor of figure 3; Figures 5 and 6 are views identical respectively to figures 3 and 4, the contactor being in the working position; Figure 7 is an euploded perspective view on a larger scale of the assembly formed by the contact holder and the plate for setting the opening contact bridges; Figure 8 is a schematic elevational view of the case of the contactor during the phase of assembling the lid with its base; and Figure 9 shows, as a function of the travel of the mobile armature of the electromagnet, the diagram of the resistant forces in the.case of the opening contacts once set and for a given drive torque of the electromagnet.

In one embodiment, the switching apparatus with electromagnetic control illustrated in the figures is a four-pole contactor with two opening poles and two closure poles.

For the sake of clarity in the rest of the description, the construction of the two opening poles and of the two closure poles will be made f irst of all with reference to figures 3 and 4.

Each of the two opening poles is formed of a contact 4 bridge referenced PR and formed by a strip 1 urged by a contact pressure spring 2 and carrying, in the form of a bridge, two mobile opening contacts R occupying a socalled normally closed position with two fixed contacts R' when the contactor is in the rest condition (electromagnet not energized).

As for the two closure poles, each of them is formed of a contact bridge referenced PP formed by a strip 3 urged by a contact pressure spring 4 and carrying, in the form of a bridge, two mobxle closure contacts P occupying a so-called normally open position with two fixed contacts P' when a contactor is in the rest condition.

The., four-p. _e contactor illustrated in figure 1 comprises a modular case 10 formed of a base 11 and a lid 12 moulded from a plastic material and snap-fitting mutually together. The base 11 of the case comprises a bottom 13 having means for mounting particularly on a standardized rail.

Case 10 is moreover provided with power terminals Al - A4 and B, - B4 and control terminals A5, B5.

In figure 2, lid 12 has been removed and the different component elements of the contactor can be seen, namely mainly a control electromagnet 15 and a mobile contact holder block 16.

The power terminals Al - A4 and B, - B4 and control terminals A5, B5 have screw clamping pieces 17 fixed to fixed contact pieces 18 (figures 3 and 5) and separated from each other by dividing walls 20 of base 11.

As can be seen in figure 2, the electromagnet 15 is formed of a coil 22 wound on a moulded carcass- 23 and a magnetic circuit formed of a fixed armature 24 and a mobile armature 25. The two armatures 24, 25 are identical, have an E shape and are formed from a magnetic metal sheet cut out and assembled, for example by rivets.

A spiralled return spring 26 is mounted between the mobile arnature 25 and the coil-carrying carcass 23.

1 The contact holder block 16, better seen in f igures 4, 6 and 7, comprises a moulded insulating cage 28 of an approximately parallelepipedic shape having two superimposed rows of recesses or windows, four per row 1,n this embodiment.

The recesses of the lower row, referenced at 30 in figures 4, 6 and 7, have a rectangular shape and are intended to receive the two mobile closure contact bridges PP. In this example, the two contact bridges PP are engaged respectively in the two intermediate recesses 30 of said row, with contacts P directed upwards, and are each supported by the associated contact pressure spring 4 attached to a stud 31 provided at the base of recess 30.

On the other hand, the recesses of the upper row, referenced at 34 in figures 4, 6 and 7, are in the form of an outwardly open U, as can be seen in f igure 7, and are intended to receive the two mobile opening contact bridges PR. In this example, the two contact- bridges PR are engaged respectively in the two endmost recesses 34 of said row, with contacts R directed downwards and each supporting, by their face opposite the contacts, the associated contact pressure spring 2.

As shown in figure 7, cage 28 of the contact holder 16 is bordered laterally by two external vertically extending walls 35 and comprises internal vertical insulating walls 36, here three in number, separating the U-shaped recesses 34 from each other.

The U shape of these recesses 34 of the contact holder has the advantage of facilitating the assembly of the mobile contact bridges PR and of the compression springs 2 by lowering simply into these recesses, as can be seen in figure 7.

In accordance with the invention, an insulating plate 39, for example rectangular in shape, is disposed in the f orm of a cap or cover over the U-shaped recesses 34 of the ccntact holder 16 and is fixedly mounted in case 6 10, so that the contact pressure springs 2 associated with the mobile opening contact bridges PR each bear both on the contact bridges PR and on the lower face 39a of the fixed plate 39. % As can be seen in figure 7, plate 39 is pierced with cavities 40, here three in number, of the same shape as the insulating walls 30 of the contact holder 16 and intended to allow the free passage of the walls during a translational movement of the contact holder 16 under the action of the electiomagnet.

As shown in figures 3 and 5, the apertured plate 39 extends on each side of the contact holder 16 and is ap,,..Lied f li. by its lower f ace 39a on f ixed supports 42 provided in the base of the case. In one embodiment, lid 12 of the case, f igure 8, is provided on the inside with vertical hol&ing lugs 44 which are applied 6n the upper face 39b of plate 39 at the time when the lid is positioned so as tc maintain plate 39 in position, see figures 3 and 5. 20 It should be noted that plate 39 could be f ixed to the base of the case using other appropriate fixing means such, for example, as screws, without departing f rom the spirit of the invention. Plate 39 forms then a simple piece-serving as common f ixed support for the contact pressure springs associated with the mobile opening contact bridges PR, which opening contact bridges are thus immobilized, so as to reduce the resistant forces at the start of movement of the contact holder.

During assembly of the contactor, figure 2, the mobile E-shaped armature 25 of electromagnei; 15 is mounted over plate 39 while being oriented in the direction of the length of base 11 of the case and is fixed to the contact holder 16 by appropriate assembly means.

In one embodiment illustrated in figures 3, 4, 5 and 6, these assembly means comprise a transverse key 46 7 (figures 3, 5) which is fitted firmly in a groove 47 provided at the foot of the central leg of the mobile Eshaped armature 25 and which is provided with two appropriate support conformations 48 (figures 4, Q) projecting on each side of armature 25 and being housed in abutment under two retainer wings 49 mounted respectively over two insulating walls 36 of the contact holder 16.

It should be noted that an insulating film (not shown) may be inserted between the mobile armature 25 of the electromagnet and plate 39 so as to increase the leak lines.

As shown in figure 2, plate 39 further comprises, on each side of the contact holder 16, retention orifices 51 receiving snap-fitting lugs 52 moulded integrally with the coil-carrying carcass 23. Thus, plate 39 also serves as support for fixing the coil-carrying carcass 23.

In f igure 2, a pivoting display lever 54 has been shown having an arm with at one end a display element 55 capable of appearing in front of a window 56 (figure 1) formed in a projecting central portion or nose 12a of lid 12 for indicating the operating state of the contactor. The pivoting lever 54 (figure 2) is mounted, on the one hand, by means of two swivels 58 on a fork-shaped piece 59 integral with the assembly key provided on the mobile armature 25 and, on the other hand, by means of two tenons 60, only one of which is visible in figure 2, on an engagement piece 61 with two claws 61a mounted vertically on plate 39 while being fixed thereto; the pivoting lever 54 is formed so that a translational movement of the mobile armature 25 of the electromagnet of the contactor causes rotation of the display element 55 so as to bring it in front of window 56 or remove it from this window.

Preferably, the engagement piece 61 integral with the apertured plate 39 is integrally moulded therewith.

Thus, plate 39 also serves, by its engagement piece 61 as support for the display lever 54.

8 At the time of assembly of the contactor, the contact holder 16 housing the mobile closure PP and opening PR contacts associated with their respective compression springs is capped by the apertured plate 3q, which is immobilized by interlocking of the mobile Eshaped armature 25 with the contact holder 16 by means of the assembly key 46; the pivoting display lever 54 is mounted on pieces 59, 61 and the spiralled return spring 26 is engaged about the central leg of the mobile E-shaped armature 25, bee figure 2.

The sub-assembly thus formed is then fitted into its housing in base 11, plate 39 resting flat on the fixed suppr _s 42 of the base (figures 3 and 5); the coilholding carcass 23, figure 2, is laid on the spring 26 then is snap-fitted by means of elements 51, 52 on plate 39 with compression of spring 26.

After setting the fixed E-shaped armature 24 on carcass 23, w.-th the central leg of the E inserted in a recess 63 (figure 2) provided in the carcass 23, and insertion of the fixed contact pieces 18 and clamping pieces 17 in their housings in the base, the lid 12 is positioned as shown by the arrow A of f igure 8 with the holding lugs 44 applied on plate 39 (figures 3 and 5); when the lid is fitted on the base, the f ixed E-shaped 25 armature 24 is housed in the nose 12a of lid 12. It will be mentioned that plate 39 may also comprise insulating skirts (not shown) serving as dividing walls between extinction chambers so as to form a baffle effect at the level thereof. 30 In the rest position illustrated in figure 3, contacts R, R' are normally closed with a contact pressure exerted by springs 2, and contacts P, P' are normally open. The contactor reaches the working position shown in 35 figure 5 when coil 22 of the electromagnet 15 is energized. By such energization, the fiKed armature 24 of the 9 magnetic circuit attracts towards it the mobile armature 25 which raises and drives in translation the contact holder 16 and so the bridges PR and PP, the dividing walls 36 of the contact holder passing into the cavities 40 of the f ixed plate 39, until contacts R, R' are open and contacts P, P' are closed, then crushing the springs 2, 4 associated respectively with bridges PR, PP.

Figure 9 shows, as a function of the travel C of the mobile armature of the electromagnet, the forces F to be overcome to cause the contactor to pass from its rest position (figure 3) to its working position (figure 5) while paying attention solely to the mobile opening contacts R for a given drive torque of the electromagnet such as shown at I in figure 9.

In this same figure 9, the corresponding diagram has been shown at II of the resistant forces to be overcome by the electromagnet which are broken down first of all into a first force Fl due solely to the spiralled spring 26 at the start of the movement of the contact holder driven by the mobile armature until contacts R, R' open at the point referenced 0 in figure 9; the mobile opening contacts being set, i.e. supported by the contact pressure springs mounted to bear fixedly on the plate, the forces due to these springs are totally annihilated at the start of movement of the contact holder.

It should be noted that, because of the fixed plate setting the mobile open ing contacts ' at the start of the electromagnet, a resistant force is obtained which is strictly identical to that of a mobile closure contact, which makes i t possible to use a single return spring for the electromagnet whatever the composition of the contacts chosen for the contactor.

After opening of the contacts R, RI, the electromagnet must then overcome a second force referenced F2 in f igure 9 and equal to the sum of the force due to the spiralled spring 26 and the forces due to the compression springs 2 associated with the mobile opening contact bridges PR.

It goes without saying that the invention described above. is not limited to a four-pole contactor with two opening poles and two closure poles. It also applies to a four-pole contactor with four opening poles and, more generally, to any multi-pole electromagnetic switch comprising several opening poles combined or not with closure poles.

19 z 1

Claims

1. Switching apparatus with electromagnetic control, comprising in a case:

- an electromagnet (15) formed of an energization coil (22) and a magnetic circuit comprising a fixed armature (24) and a mobile armature (25) urged by a return spring (26); - a plurality of opening poles each having a bridge of mobile contacts (PR) cooperating with fixed contacts (R').

- a contact holder block (16)having a row of parallel identical recesses (34), in number equal to or greater than the number of opening poles, in which are engaged the mobile contact bridges (PR) each slaved to a contact pressure spring (2), the contact holder (16) being fast with the mobile armature (25) of the electromagnet and being movable in translation between a rest position in which the contacts (R, R) are normally closed and a working position in which the contacts (R, R') open through attraction of the mobile armature (25) by the fixed armature (24) at the time of energization of the coil (22), characterized in that - the recesses (34) of the contact holder (16) are in the form of a U opening outwardly, on the mobile armature side of the electromagnet, these U-shaped recesses forming insulating walls (36) therebetween; - a plate (39) for setting the mobile contact bridges (PR) is inserted between the contact holder (16) and the mobile armature (25) of the electromagnet, so as to cap the Ushaped recesses (34) of the contact holder, this plate (39) being mounted f ixedly in the case so as to form a fixed support for the contact pressure springs (2) housed in the recesses (34) and placed as support for the associated mobile contact bridges (PR), and being pierced with cavities (40) for the passage of the insulating wc.lls (36) of the contact holder (16) during movement thereof, which contact holder is connected to the mobile armature of the electromagnet by appropriate assembly means.

2. Switching apparatus according to claim 1, in which the case is formed of a base (11) and a lid (12), characterized in that the plate (39) extends on each side of the contact holder (16) in a plane perpendicular to the direction of movement of the contact holder, in that the base (11) of the case has fixed supports (42) on which a first face (39a) of the plate (39) situated on the contact side is applied flat, on each side of the contact holder and in that the lid (12) has on the inside holding lugs (44) applied on a second face (39b) of the plate (39) opposite the first one.

3. Switching apparatus according to claim 2, in which the fixed (24) and mobile (25) armatures of the electromagnet are in the form of an E, chardcterIzed in that the E-shaped armatures (24, 25) are disposed in the direction of the length of the base (11) and in that the means for assembling the mobile E-shaped armature (25) with the contact holder (16) comprise a transverse key (46) which is fitted firmly in a groove (47) provided at the foot of the central leg of the Eshaped armature (25) and which is provided with two appropriate conformations (48) projecting on.each side of the armature (25) and being housed in abutment under two retainer wings (49) mounted respectively over two insulating dividing walls (36) of the contact holder (16).

4. Switching apparatus according to -claim 3, in which the lid (12) of the "ase has a front face (12a) with a window (56) for displaying the state of the apparatus, characterized in that a pivoting display lever (54), known per se, is carried by two engagement members (59, 61), -ne of which (59) is fast with one of the conformations of the key (46) of the mobile E-shaped armature (25) and the other of which (61) is f ast with the plate (39), said lever (54) being provided with a display element (55) capable of being brought opposite the window (56) or removed therefrom.

5. Switching apparatus according to one of claims 2 to 4, in which the energization coil (22) is carried by a carcazg (23) characterized in that the plate (39) further comprises, on each side of the contact holder, retainer orifices (51) in which are fitted snap- fitting lugs (52) formed on the coil-carrying carcass (23) so that the plate (39) also 10 serves as fixing support for the carcass (23).

6. Switching-apparatus according to claims 4 and 5, characterized in that the apertured plate (39) as well as the engagement member (61) which is integral therewith form a single piece moulded from an insulating material.

7. Switching apparatus with electromagnetic control substantially as described herein with reference to the tecompanying drawings.

Published 1991 at The Patent Office. State House. 66171 High Holborn. London WC 1 R 4TP. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Pbint Cwmfelinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray. Kent.