Laterally actuated electrical switch

Abstract: The invention provides an electrical switch of the type comprising a support (10, 12) carrying contacts (30, 34), which delimits a housing (22) in the bottom (26) of which are arranged at least two fixed electrical contacts (30, 34) and which receives a tripping member (36) which can deform elastically in a vertical direction (V) substantially perpendicular to the bottom (26) of the housing (22), and of the type comprising an actuating pusher (44) mounted so as to slide (10, 12) in a lateral direction (H), in order to act on the tripping member (36) via mechanical means (48) which convert the actuation force exerted on the pusher (44) into a perpendicular force applied to the tripping member (36), characterized in that it comprises an actuating lever (48) mounted so as to pivot with respect to the support (10, 12) about an axis (X-X) parallel to the bottom (26) of the housing (22) and in that the lever (48) is returned elastically to its rest position.

Description: The present invention relates to an electrical switch. The invention relates especially to a laterally actuated switch, of very small size, of the type comprising a support carrying contacts which delimits a housing in the substantially plane bottom of which are arranged at least two fixed electrical contacts and which receives a tripping member of domed overall shape which can deform elastically from a rest position in a direction substantially perpendicular to the bottom of the housing, in order to establish an electrical connection between the two fixed contacts, and of the type comprising an actuation pusher mounted so as to slide with respect to the support, in a lateral direction parallel to the bottom of the housing, in order to act on the tripping member via mechanical means which convert the actuation force exerted on the pusher into a perpendicular tripping force applied to the tripping member, from a rest position to which it is returned elastically. An example of such a switch, described and shown in document JP-A-02,195,616 is known, in which the means for converting the lateral direction of the actuation force consist of an articulated part of the pusher which interacts with a ramp formed by a cut-out in the upper wall of a cover of the switch. This design is not satisfactory insofar as the cut-out in the cover prevents easy gripping of the switch by suction, especially during surface-mounting operations on a printed-circuit board. In addition, the construction of the pusher, with an articulated part connected to the body of the pusher by a thinned portion forming a pivoting hinge, is difficult to accomplish and requires the pusher to be guided very precisely. In order to remedy these drawbacks, the document FR-A-2,734,398 has proposed an electrical switch of the abovementioned type in which the lateral actuating pusher acts on the tripping member via an actuating lever which is mounted so as to pivot with respect to the support about a transverse axis parallel to the bottom of the housing and perpendicular to the sliding direction of the pusher, a bearing point of which interacts with the tripping member whose point of application of the driving force by the pusher interacts with a portion of the pusher in the form of an inclined ramp, and which is elastically returned to its rest position, so as to convert the actuation force exerted on the pusher into a perpendicular tripping force applied to the tripping member. According to the embodiment described in that document, the lever is made in the form of an elastically deformable metal blade which extends above the tripping member and one end of which is fastened to the support by a fastening section which is extended by an active section in the form of a loop, one portion of which interacts with the ramp of the pusher and one portion of which interacts with the central facing part of the actuating member. The object of the present invention is to provide another embodiment of the design principle of the switch described and illustrated in the document FR-A-2,734,398 which especially makes it possible to reduce the total height of it, to reduce the total weight of it, to have greater operational reliability and not to require the use of complex cutting and folding techniques like for the production of the lever plate. For this purpose, the invention provides a switch of the abovementioned type, characterized in that the lever is a piece in the overall shape of a T, one branch of which constitutes the front pivot pin of the lever, with each of its two opposed transverse ends which is received in a bearing housing of the support, and the other, central branch of which extends overall in the lateral direction of actuation by the pusher, at its rear free end, which constitutes the point of application of the force and has, on its lower face, the point which bears on the tripping member. According to other characteristics of the invention; the lever may be a moulded plastic piece; the lever is delimited by two parallel plane faces, an upper one and a lower one; the bearing point is a boss in the form of a spherical cover formed on the lower face of the central actuating branch; the upper face of the rear free end of the central actuating branch has a convex curved profile in order to interact with an inclined plane ramp formed opposite the front free end of the actuating pusher; the switch comprises a cover whose solid upper wall extends above the upper face of the pusher and the lever, parallel to the bottom of the housing; the lever is returned elastically to a high rest position in which it bears against the lower face of the upper wall of the cover; each bearing housing formed in the support emerges vertically upwards and is closed by an opposing portion of the lower face of the upper plate of the cover. Further characteristics and advantages of the invention will appear on reading the detailed description which follows, for the understanding of which reference may be made to the appended drawings in which: Figure 1 is an exploded perspective view from above of the various components of a laterally actuated switch produced according to the teachings of the invention; Figure 2 is an exploded perspective view from below of the components illustrated in Figure 1; Figure 3 is a perspective view on a larger scale of the switch in the assembled position; Figure 4 is a view on a large scale in cross section on the vertical transverse plane 4-4 in Figure 3 passing through the pivot pin of the lever which is illustrated in the high rest position; Figure 5 is a view on a large scale in cross section on the vertical mid-plane 5-5 in Figure 3 which illustrates the pusher in the rear rest position. The figures show a lower contact-carrying support in which, according to a known design, mainly consists of a body or case 12 made by moulding an insulating plastic and of rectangular parallelepipedal overall shape. The body 10 is delimited by lateral faces 14 and transverse faces 16, by a lower face 18 and by a horizontal upper face 20 in which a housing 22 opens. The housing 22 is delimited by a peripheral wall 24 of rectangular outline and by a bottom 25 which is substantially plane and parallel to the upper face 20. The body 12 is made by overmoulding over conducting elements which constitute, in the example illustrated in the figures, a series of four fixed electrical contacts 26. The switch also has an upper closure cover 102. As may be seen especially in Figures 1 to 4, each fixed electrical contact 26 consists of a metal strip which is bent so that its end 28, lying inside the housing 22, is flush with the plane bottom 25 of the latter while its outer end 30 projects outside the case 12, beyond the lateral face 14, in order to form a connection terminal which, in this design, allows the switch 10 to be mounted on a printed-circuit board (not shown), for example using the technique of surface mounting. The fixed contacts 26 here are four in number, which extend longitudinally parallel to each other and which are associated as a pair of fixed contacts 26 aligned two by two in the bottom 25 of the housing 22. The inner ends of the contact 28 lie in the same plane corresponding to the plane of the bottom 25, the latter being completed, near the small internal lateral faces of the internal peripheral wall 24, by two raised bases 32 produced with the body by moulding in an insulating material and each of which bases defines a horizontal bearing surface parallel to the plane bottom 25 to which this bearing surface is joined by a chamfer. According to a known design, the switch 10 includes a tripping member 36 designed to be housed in the housing 22 which is an element produced from a sheet, for example a metal sheet, which has a domed overall shape, the lower outline 38 of which here is rectangular and has dimensions complementary to those of the internal peripheral wall 24 so as to be housed in the housing 22. The tripping member 36 mainly consists of a lower baseplate and of a central upper part 40. The lower outline 38 delimits a lower general plane for the tripping member 36 to bear on in the housing 22. The overall concavity of the tripping member 36 faces the bottom 25 and the tripping member is capable of being deformed, against its own elasticity, in a vertical tripping direction V and from its stable rest state illustrated in the figures to an unstable trip state for establishing electrical contacts. According to a known design, the tripping member 36 changes state suddenly, beyond a defined tripping travel, so as to transmit to the user a tactile sensation of the tripping. According to the teachings of French Patent Application FR-A-2,771,846, and in order to establish electrical contact between the various fixed contacts 26 almost simultaneously, a contact plate 43 in the form of a grid, made of conducting material, is interposed axially between the tripping member 36 and the fixed contacts 26. The contact plate 43 is designed to bear via its opposed lateral edges 46 on the bearing surfaces of the raised bases 32. Thus, in the assembled position, and as may be seen in Figure 5, the horizontal general plane of the contact plate 43 is offset vertically upwards with respect to the general plane of the bottom 25 of the housing 22. In the example illustrated in the figures, in which the insulating case 12 has four fixed contacts 26, the contact plate 43 is cut so as to have four electrical contact blades 50, 50', each of which is associated respectively with one fixed contact 26. In their rest state, illustrated especially in Figures 1 and 2, three contact blades 50 extend in the general plane of the contact plate 43 and the fourth contact blade 50' is bent downwards in order to form a common contact permanently in contact with a fixed contact 26. The four free ends of the blades 50, 50' all lie more or less vertically in line with the central active part 40 of the monostable tripping member 36. In the rest position, the height of the member 36 is less than the depth of the housing 22 and the latter is covered with a protective and sealing double film 42. The film 42 is made of a pliant material so as to act on the member 36, the film 42 furthermore having an adhesive face sealing it to the upper face 21 of a peripheral internal shoulder, and therefore sealing the housing 22 in which the tripping member 36 and the plate 43 are placed. The means for actuating the member 36 essentially consist of a lateral actuating pusher 44 and an actuating lever 48. The pusher 44 is a moulded piece made of plastic, of rectangular parallelepipedal overall shape, which is delimited by a lower face 82, a parallel upper face 84, two lateral faces 86, by a rear transverse actuating face 88 and by a transverse front end face 90. The end part 90 of the pusher 44 has a central recess 92 opening to the front, which is longitudinally delimited rearwards by a ramp 94 inclined at approximately 45° and which is designed to interact with a convex curved portion 76 of the lever 48. The set of components 10, 43, 36, 42, 44 and 48 is held stacked vertically and assembled by the upper cover 102 which is made in the form of a piece made of cut and bent sheet metal. The cover has a plane, solid and rectangular upper horizontal wall 104 which extends above the upper face 84 of the pusher 44 and above the lever. The upper wall 104 is continuous and allows for easy grasping, for example by suction, of the switch in order to position it precisely and automatically on a printed-circuit board, this being so despite the very small size of the switch. The wall 104 is extended vertically by two vertical lateral tabs 106 which extend in complimentary recesses 107 in the lateral faces 16 of the contact-carrying support. The front and rear transverse edges of the upper wall 104 are also extended downwards by two transverse vertical tabs 108 which extend in facing recesses 109 in the transverse face 16 of the contact-carrying support 10. The rear tabs 108 delimit between them a central cut-out 110 for passage of the body of the pusher 44. The lower end of each tab 108 has a tab 116 which is slightly bent back transversely towards the inside of the cover 102. The lower tabs 116 enable the cover 102 to be crimped in the mounted position onto the contact-carrying support 10, the body 12 of which includes, in its corresponding transverse face 16, recesses 120 which house the tabs 116. At the front of the cover 102, it will be noticed that there is no cut-out between the two tabs 108. The rear tabs 108 also act as a rear stop for the pusher 44 in the rest position, these being housed at the bottom of two rear grooves 95 in the body of the pusher 44. The design according to the invention of the actuating lever 48 will now be described in detail, this lever being produced in the form of a moulded plastic piece placed horizontally in the extension of the lateral pusher 44. The lever 48 has the overall shape of a "T" lying approximately horizontally and has a transverse rear pivoting branch 50 and a central actuating branch 52 which extends laterally rearwards from the pivoting branch 50 with its rear free end section 54 which is housed inside the central recess 92 in the pusher 44. The lever 48 is delimited vertically by two parallel plane faces, an upper one 56 and a lower one 58. Each of the free ends 60 of the rear pivoting branch 50 constitutes a pivot for the lever 48 to pivot about a horizontal axis X-X inside the support 10. For this purpose, each end 60 is housed in a complementary bearing housing 62 formed in the support 10. Each housing 62 emerges vertically upwards in order to allow the lever 48 to be put into place vertically downwards in the support 10. The lower face 58 of the actuating branch 52 has a raised boss 64 in the form of a spherical cover, which lies vertically in line with the central part 40 of the tripping dome 36 bearing on the film 42. In this position, the upper face 56 of the lever 48 and the upper face 84 of the pusher 44 extend opposite the lower face 23 of the upper plate 24 of the cover 102. The mode of operation of the switch will now be described. In the rest position illustrated in the figures, the switch is in the rest position and the tripping member 36 is in the free state. From this rest position, the user acts on the pusher 44 by applying to it, directly or indirectly, a lateral actuation force, from the rear forwards, on its face 88 in the lateral sliding direction H, i.e. from the right to the left in Figure 5. The pusher 44 slides as far as its extreme front tripping position. During this sliding movement, the lever 48 pivots clockwise substantially about the axis X-X. The bearing point 64 moves vertically so as to act on the central part 40 of the dome 36. This movement results in the interaction of the ramp 94 with the convex cam 76 of the actuating branch 52. When the actuation force is released, the plate 43 and the tripping member 36 release the energy which they have stored during the actuation, in order to resume their rest state and to return the lever 48 by pivoting overall anticlockwise about the axis X-X, and thus indirectly to push back the pusher 44, from the left to the right, because of the arrangement of the ramp 94. The design of the switch according to the invention is particularly compact. Thus, its total height is less than about 1.4 mm and its depth, in the direction H, is less than 4.4 mm. The actuating force has to be applied to the pusher 44 in order to trip the switch is particularly small, as is the hysteresis effect in the trip-release cycle.

Claims: Electrical switch of the type comprising a lower support (10, 12) carrying contacts (28), which delimits a housing (22) in the bottom (26) of which are arranged at least two fixed electrical contacts (28) and which receives a tripping member (36) of domed overall shape which can deform elastically from a stable rest position, in a vertical direction (V) substantially perpendicular to the bottom (26) of the housing (22), in order to establish an electrical connection between the two fixed contacts (28), and of the type comprising a lateral actuation pusher (44) mounted so as to slide from the rear forwards with respect to the support (10, 12) in a horizontal direction (H) parallel to the bottom (26) of the housing (22), in order to act on the tripping member (36) via an actuating lever (48) which is mounted so as to pivot with respect to the support (10, 12) about a transverse axis (X-X) parallel to the bottom (26) of the housing (22) and perpendicular to the sliding direction (H) of the pusher (44), a bearing point of which interacts with the tripping member (36, 40) whose point of application of the driving force by the pusher (44) interacts with a portion (90, 94) of the pusher (44) in the form of an inclined ramp (94), and which is elastically returned to its rest position, so as to convert the actuation force exerted on the pusher (44) into a perpendicular tripping force applied to the tripping member (36), characterized in that the lever (48) is a piece in the overall shape of a T, one branch (50) of which constitutes the front pivot pin of the lever (48), with each of its two opposed transverse ends (60) each housed in a bearing housing (62) of the support, and the other, central branch (52) of which extends overall in the lateral direction (H) of actuation by the pusher (44), the rear free end (76) of the central branch (52) constituting the point of application of the force and has, on its lower face (58), a point (64) which bears on the tripping member (36, 40). Switch according to the preceding claim, characterized in that the lever (48) is a moulded plastic piece. Switch according to either of the preceding claims, characterized in that the lever (48) is delimited by two parallel plane faces, an upper one (56) and a lower one (58). Switch according to any one of the preceding claims, characterized in that the bearing point is a boss (64) in the form of a spherical cover formed on the lower face of the central actuating branch. Switch according to any one of the preceding claims, characterized in that the upper face (76) of the rear free end of the central actuating branch (52) has a convex curved profile in order to interact with an inclined plane ramp (94) formed opposite the front free end of the lateral actuating pusher (44). Electrical switch according to any one of the preceding claims, characterized in that it comprises a cover (102) whose solid upper wall (104) extends above the upper face of the pusher (44) and the lever (48), parallel to the bottom (25) of the housing (22). Switch according to the preceding claim, characterized in that the lever (48) is returned elastically to a high rest position in which it bears against the lower face (23) of the upper wall (24) of the cover (102). Switch according to Claim 6, characterized in that each bearing housing (62) formed in the support (10) emerges vertically upwards and is closed by an opposing portion of the lower face of the upper plate of the cover.

Inventors: BOUVIER LAURENT, BURNEL THIERRY, ROCHON SYLVAIN, BOUVIER, LAURENT, BURNEL, THIERRY, ROCHON, SYLVAIN
Applicants: ITT MFG ENTERPRISES INC, ITT MANUFACTURING ENTERPRISES, INC.
Application year: 2000
Main classification: H01H13
IPC codes: H01H13, H01H15