FR2552926A1 - IMPROVEMENTS ON SWITCHES WITH TILTING CONTACT HOLDER - Google Patents

Abstract

1. A switch comprising, inside a housing (1), at least one movable contact (2) which is held longitudinally on a contact arm (3) adapted to pivot between a working position in which it brings an active region (4) of the movable contact (2) into contact with an active region (5) of a fixed contact (6) with a force determined by the action of a spring (7), and another position in which it holds these two active regions (4, 5) apart from one another, which spring (7) acts at a point of action (P) on the movable contact (2) in such a manner as to urge the latter against the contact arm (3) at two reaction points (Q, R) which are spaced apart from one another on on the movable contact (2), one (Q) of these reaction points being further away and the other (R) being less far away from the active region (4) of the movable contact (2) than the point of action (P), characterized in that the spring (7) is a compression spring which is compressed between the movable contact (2) and the housing (1) and in that the movable contact (2) is held longitudinally on the contact arm (3) by means (19, 20) which are independent of the spring (7).

Description

Improvements to switches with tilting contact carrier

  The invention relates to switches provided with at least one movable contact which is mounted on a contact carrier capable of switching between a working position, where it places an active area of the movable contact in contact with an active area of a fixed contact under 10 a pressure determined by the action of a compression spring, and a rest position, where it maintains

  these two active zones separated from one another The invention relates more particularly, but not exclusively, to switches and automatic cut-off and more particularly still to differential switches.

  By "active area" of the fixed or mobile contact, is meant a projecting area, formed either directly by deformation on the contact considered, or more generally on an element such as a rivet, attached to

this contact.

  The invention aims to simplify the construction of these switches, in particular by making

  perform an additional function to the above mentioned spring.

  To achieve this object, the switch according to the invention is essentially characterized in that the compression spring acts on the movable contact at a point thereof (hereinafter called "action point") which is located on the same face as the active area of this movable contact, so as to push the latter against the contact carrier at two points (hereinafter called "reaction points") which are separated from one another and located on the other side of the mobile contact, one of these reaction points being more distant and the other less distant from the active area of the mobile contact than the action point. 10 By "point" either of action or of reaction, we want to emphasize the local character of the area by which the spring acts on the movable contact as well as the area by which the contact carrier reacts on it without of course wanting to limit itself to the purely geometric acceptance of the term "point" This is how

  that, by this term, is meant to include for example a generator perpendicular to the axis of tilting of the contact carrier or a surface generated by such a generator, along a short guiding curve.

  In the switch defined above and as will be explained in more detail below, the above-mentioned spring not only exerts in a known manner the pressure for applying the active areas of the contacts against each other in working position, but still tends to separate these active zones from one another during the transition from the working position to the rest position and to keep them separated from one another in the position

rest.

  The invention will now be described in more detail using the attached drawing which illustrates one of them.

preferred embodiment.

  Figure 1 of this drawing represents, in elevation

  schematic, the essential elements of this mode of realization

sation, in working position.

  Figure 2 shows the same elements as

Figure 1, in the rest position.

  Figure 3 shows the same elements as Figure 1, in the momentary position of contact cleaning.

  Figure 4 shows an end view of the contact holder with partial sections passing through the axis of the contact holder and its reaction point.

  The switch shown in Figures i and 2 comprises an insulating housing of which only one wall element has been shown 1 Inside this case, a movable contact 2, in the form of a blade, is mounted on a contact holder 3 , made of insulating material, capable of tilting, around an axis X, between a working position (FIG. 1) and a rest position (FIG. 2) In the working position (FIG. 1), the contact carrier 3 puts an active area 4 of the movable contact 2 in contact with an active area 5 of a fixed contact 6, under a pressure determined by the action of a helical compression spring 7 In the rest position (FIG. 2), the contact carrier 3 keeps the two active zones 4, 5 spaced from one another. According to the embodiment shown, the active zones, 4 and 5 are formed by surfaces belonging respectively to a rivet 8, attached to movable contact 2, and to a rivet

9, attached to the fixed contact 6.

  The fixed contact 6 is secured to the housing by means not shown. The contact carrier 3 is mounted on the housing, for example by means of pins 10 engaged in corresponding holes in the housing, so as to be able to oscillate around the axis X. In accordance with the invention, the compression spring 7 acts on the movable contact 2 at a point 35 P thereof which is located on the same face 11 as the active area 4 of this movable contact 2 so as to push the latter against the contact carrier 3 at two points Q and R which are spaced from one another and situated on the other face 12 of the movable contact 2 The point P is designated by "action point 5" and by "reaction points" the points Q and R The reaction point Q is more distant from the active area 4 and the reaction point R less distant from this active area 4 than the action point P In other words , if we neglect the thickness of the movable contact 2, we can say that the point of action is located between points Q and R. De preferen ce, point P is constituted by a deformation of the movable contact 2 in the form of a roll or semi-cylindrical projection 15 while the reaction points Q and R are materialized respectively by

  semi-cylindrical projections 13 and 14 molded with the contact holder 3 As shown in the figures, the action point P is located approximately halfway between points Q and R, if we neglect the thickness of the contact 20 mobile 2.

  The compression spring 7 is supported, by

  one end, on the wall element 1 and acts by its other end on the roller 15 For this purpose, this other end can be constituted by a turn 16 25 more or less closed on itself in a ring.

  The contact carrier 3 is actuated by means (not shown) which attack it through a hole 17 formed at one of its ends, the assembly being such that the contact carrier 3 is always stopped alternately 30 at the two positions limit switches shown In the limit switch position shown in Figure 1 (working position), o the two active zones 4 and 5 are in contact with each other and o the movable contact 2 touches the door -contact 3 at the reaction point 35 R the least distant from its active area 4, the assembly is -5 as there is (at least in the absence of significant wear of the rivets 8 and 9) a stroke d wear a between the face 12 of the movable contact 2 and the contact carrier 3 at the other reaction point P i.e.

at the level of the projection 13.

  Preferably, the blade constituting the movable contact 2 is bent, as shown in the figures, between two rectilinear parts roughly parallel to each other, namely a first part where the action points P and the QR reaction are located. and a second part o is located the active zone 4, thanks to the presence of an inclined intermediate part 18, so as to increase the space available for housing

of spring 7.

  Finally, the distance b between the reaction point 15 R the least distant from the active area 4 of the movable contact 2 and the point P is preferably of the order of half the distance c between this same reaction point R and the above active area 4, these distances being measured

  in the longitudinal direction of the movable contact 2.

  Furthermore, the contact carrier 3 has, on either side of the lateral ends of the boss forming the reaction zone R, two small bosses 19 oriented downwards and penetrating with relatively little play in two lateral notches 20 formed in the 25 first rectilinear part of the contact 2, at a short distance from the inclined part 18 A connection is thus ensured substantially securing the contact carrier 3 and the contact 2 in the longitudinal direction of the contact

mobile 2.

  A switch is thus obtained, the operation of which is as follows In the working position shown in FIG. 1, the spring 7, by acting at the point of action P, tends to rotate the moving contact -6 2 around the reaction point R clockwise, i.e. applying the active area 4 of the movable contact 2 against the active area 5 of the fixed contact 6 with a force which, due to the ratio 5 existing between the distances b and c, is of the order of half the force exerted by the spring 7 on the movable contact 2 at the point of action P At the point

  reaction Q there is the wear stroke a.

  When, starting from the working position of FIG. 1, the contact carrier 3 is tilted counterclockwise around the X axis, this causes the projection 14 to rise up until that, under the action of the spring 7, the movable contact 2 comes to touch the contact carrier 3 not only at the reaction point R, but also at the reaction point Q, the active zones 4 and 5 having so far been pressed one on the other by the spring 7 From this intermediate position o the movable contact 2 has come to touch the reaction point Q the spring 20 7 ceases to exert on the movable contact 2 a torque tending to cause it to tilt around the reaction point R, clockwise Indeed, by exerting its thrust between the reaction points Q and R on the movable contact 2, it secures the latter 25 with the contact carrier 3 which therefore causes the movable contact 2 to the rest position shown in the

figure 2.

  When, starting from the rest position shown in FIG. 2, the contact holder 30 3 is tilted clockwise, the contact holder 3 causes the mobile contact 2 with it to reach the above-mentioned intermediate position o its active area 4 comes to touch the active area 5 of the fixed contact 6 We are then in the position of FIG. 3, on which we see that the active part 4 of the movable contact -7 2 comes to touch the active area 5 of the fixed contact 6 in a slightly inclined position and shifted to the left, as seen in this figure Then, when the contact holder 3 continues to move, the 5 movable contact 2 moves away from the contact holder 3 at level

  of the reaction point Q and the spring 7 exerts on the movable contact 2 an increasing torque which tends to make it rotate clockwise around the reaction point R Finally, we find ourselves in the situation described with reference in Figure 1.

  It is noted that during this final part of the tilting, the reaction point R continues to descend, which forces the contact 2 to approach the horizontal, which forces the active part 4 of the movable contact 15 2 to slide on the area. activates 5 from the fixed contact to the final position of FIG. 1, thus causing each

  times self-cleaning of contact areas.

  The wear of rivets 8 and 9 simply translates

  by a reduction in the initial wear stroke a, without disturbing the operation of the switch.

  As can be seen, the contact rivets 8, 9 are situated inside a breaking chamber 21 closed on all sides except for an opening 22 necessary for the movement of the end of the movable contact 2 which carries the rivet 8 This chamber 21 contains reinforcements 23 capable of creating a magnetic field of deionization during the separation of the

contact rivets 8, 9.

  According to an invention preferably associated with the combination of the contact carriers 3, movable contact 2 and spring 7, the contact carrier has, at the opening 22, a lip 24 whose outer surface faces the chamber 21 is circular cylindrical centered on the pivot axis X This lip 24 deter35 mines with the end 25 of the wall of the chamber 21 a very narrow passage 26 present whatever the position of the contact carrier 3, which significantly increases the electrical insulation of chamber 21 and its contents

  relative to the rest (not seen) of the switch.

  It should be noted that, in addition to the increased insulation, the assembly, arranged in accordance with the invention, of the contact carrier 3, the movable contact 2 and the spring 7, brings a significant increase in the speed of opening.

contacts.

Claims (9)

  1 Switch provided with at least one movable contact 5 (2) which is mounted on a contact carrier (3) capable of switching between a working position, where it places an active area (4) of the movable contact (2) in contact with an active zone (5) of a fixed contact (6) under a pressure determined by the action of a compression spring (7), and a rest position, where it maintains these two active zones (4 , 5) separated from each other, characterized in that the compression spring (7) acts on the movable contact (2) at an action point (P) which is located on the same face (11) as the active zone (4) 15 of this movable contact (2), so as to push the latter against the contact carrier (3) at two reaction points (Q, R) which are spaced from one another and located on the other face (12) of the movable contact (2), one (Q) of these reaction points being more distant and the other 20 (R) less distant from the active area (4) of the contact mobile (2) as the action point (P).   2 switch according to claim 1, characterized in that the action point (P) is constituted by a deformation of the movable contact (2) in the form of a projection and in that the reaction points (QR) are materialized respectively by protrusions (13, 14)   comings of molding with the contact carrier (3).   3 Switch according to one of claims   1 and 2, characterized in that the action point (P) is situated approximately halfway between the reaction points (Q, R).   4 Switch according to any one of claims 1 to 3, characterized in that, in the working position, there is a wear stroke (a) between the movable contact (2) and the contact carrier (3) , at the level   the reaction point (Q) furthest from the active area (4) of the movable contact (2).   Switch according to any one of claims 1 to 4, characterized in that the movable contact (2) is constituted by a blade counter-bent between two straight parts roughly parallel to each other, namely a first part where the action (P) and reaction (QR) points and a second part where the corresponding active area (4) is located, thanks   the presence of an inclined intermediate part (18).   6 Switch according to any one of claims 1 to 5, characterized in that the distance (b) between the reaction point (R) the least distant from the active area (4) of the movable contact (2) and the point d action (P) is of the order of half the distance (c) between this same reaction point (R) and said active area (4).   7 Switch according to any one of claims 1 to 6, characterized in that the movable contact (2) is integral in its longitudinal direction with the contact carrier (3) by means of bosses (19) 20 notches ( 20) located at the reaction point   (R) the least distant from the active area (4) of the movable contact.   8 Switch according to any one of claims 1 to 7, characterized in that the relative spatial arrangement of the contact carrier (3) and the movable contact   (2) causes, during the final part of the stroke between the position of first physical contact between the active areas (4, 5) of the contacts (2, 6) and the working position, a slight tilting of the movable contact (2) 30 causing a self-cleaning shifting of the active area (4) of the movable contact and the active area (5) of the contact fixed (6).   9 Switch according to any one of claims 1 to 8, characterized in that the active zones   it contact (4, 5) are arranged in a switching chamber 21, and in that the contact carrier (3) has, at the opening (22) of said chamber, a cylindrical lip (24) centered on the pivot axis 5 (X) of the contact carrier (3) to determine with the corresponding wall end (25) of the chamber (21), a narrow passage (26) present whatever the position of the contact carrier (3).