Electric switch

Abstract: An electric quadrant switch (10) is provided with a plastics material housing (11) in which stationary and movable contact elements (46, 47) are received, with an actuating member (18) which, for actuation of the movable contact elements (46, 47), is held in the plastics material housing (11) in such a way that it can be pivoted from a neutral position in preferably four actuation directions, the actuating member (18) having an actuator axis (21) and radially projecting actuating arms (20), and with components (24, 25, 41) causing the readjustment and sustained adoption of the neutral position by the actuating member (18). In order to achieve a good haptic sensation and a detectable switching sensation in a small installation space and with relatively low expenditure and to achieve low transmission resistances, it is provided that a switching transmission mat (51) which overlaps the movable contact element (47) at least between the contact elements (46, 47) and the actuating arm (20) of the actuating member (18) for switching movement transmission and in that the actuating arm (20) is provided at its free end with an axially projecting spring-loaded latching element (25) which, during actuation, is guided along a connecting link (41) which, in the neutral position of the actuating member (18), has a latching face (44),

Description: The present invention relates to an electric switch, in particular quadrant switch, according to the preamble of claim 1. Electric switches of this type, such as quadrant switches, are, for example, used in the actuation of rear view mirrors, seat parts etc. in motor vehicles in order to move these components into the desired position. In an electric switch of the type mentioned at the outset known from DE 198 44 336 C1, a silicone switching mat in the form of a so-called dome switching mat is used which contains movable contact elements which cooperate directly with the actuating arms of the actuating member. By pivoting the actuating member the relevant movable contact element of the dome switching mat is brought into contact with the corresponding stationary contact element by overcoming the elasticity of the attachment of the movable contact element on the plane region of the dome switching mat. While silicone switching mats of this type are inexpensive to produce and are silent in operation they do however have high transition resistances. The "spongy" switching sensation is also disadvantageous in this case, i.e. the haptic sensation upon switching is unsatisfactory, as it cannot be sufficiently determined by the operator whether and when the switching instant has been/is achieved and the switching is complete. Correspondingly higher actuating forces for a good haptic sensation is only possible with considerable expenditure which, moreover, is not possible with the desired small installation space when using dome switching mats. DE 198 53 438 A1 discloses a multi directional electric switch arrangement also of the type mentioned in the preamble and having a silicon switching mat in the form a so called dome switching mat containing moveable contact elements which cooperate directly with actuating legs of the actuating member. The actuating legs being with respect to the housing axially provided, the axially operative spring load of which performing a reset of the actuating member from a pivoted position to an upright neutral position. The same applies with respect to a reset of the actuating member with an electrical switch assembly being disclosed in EP 0 348 202 A3. US 3 828 148 discloses a multi-position electrical switch assembly having an actuating member the inner free end of which is being pivoted and acts on moveable contact elements being spring loaded. A reset of this actuating member from its pivoted positions to the upright neutral position is performed by the spring loads of the springs of the moveable contact elements and of the actuating member. The object of the present invention is therefore to create an electric switch, in particular quadrant switch, of the type mentioned at the outset which allows a good haptic sensation or detectable switching sensation with small installation space and a relatively low expenditure, and in which there are low transition resistances. To achieve this object the features described in claim 1 are provided in an electric switch, in particular quadrant switch, of the type mentioned at the outset. Owing to the measures according to the invention, a marked switching sensation is achieved, wherein virtually silent switching is possible as before, even though the silicone or dome switching mat is replaced by a silicone or switching transmission mat in combination with conventional spring contacts. The haptic sensation or the switching sensation is dependent on the type of spring-loaded latching element and the connecting link and can therefore be modified in a desired manner. The installation space can be kept small as before. With the features according to claim 2 the electric currents and resistances can be kept as small as possible owing to the metallic configuration of the contact elements and, owing to the relatively high thermal load caused thereby, SMD soldering is also possible or the switch is suitable for this. It can be expedient in this case to provide the features according to claim 3. Preferred developments of the connecting links can be inferred from the features of one or more of claims 4 to 6. A preferred development of the elements responsible for the actuating forces is provided by the features of claim 7 and/or 8. Inexpensive production and assembly is produced by the features of claim 9, wherein in order to simplify the arrangement of the connecting link the features according to claim 10 can be provided. If the measures according to claim 11 are provided on the cover in the divided configuration of the housing, a high limit strength for the actuator axis is provided in addition to an actuation limitation. Bearing of the actuating member inside the plastics material housing can be inferred from the features of one or more of claims 12 to 14. Further developments in relation to tightness against external influences, in relation to the suitability for SMD soldering and in relation to illumination or additional circuitry can be inferred from the features of claim 15 and 16 and 17. Further details of the invention can be inferred from the following description in which the invention is described and explained in more detail with the aid of the embodiment illustrated in the drawings, in which: Fig. 1 is a longitudinal section through a quadrant switch according to a preferred embodiment of the present invention, in the neutral position, Fig. 2 is a partially opened up top view of the quadrant switch according to Fig. 1, Fig. 3 is a section similar to that in Fig. 1, but in a pivoted end position of the quadrant switch and Fig. 4A and 4B each show a side view of a variation of the quadrant switch according to claim 1. The electric switch designed as quadrant switch 10 and illustrated in the drawings can, in the embodiment illustrated, be brought from its neutral position according to Fig. 1 into four defined functional positions, of which one is illustrated in Fig. 3. It goes without saying that this electric switch can also be reduced in that it only has to carry out two displacement operations instead of four displacement operations. The quadrant switch 10 has a housing 11 with a rhombic area made of plastics material which is composed of a pot-shaped main component 12 and a cover 13 introduced into the open end of the main component 12. The pot-shaped main component 12 is provided at its base 28 with feet 14 by means of which it is placed on a printed circuit board 15 illustrated only in Fig. 4A and 4B or, as shown there, can be fastened thereto with hooks. The electrical connection to the printed circuit board 15 is made by means of connecting legs 16 which are electrically connected to the corresponding contact elements 46 and 47, yet to be described, inside the housing 11 of the quadrant switch 10. The metallic contact legs 16 can be brought into electrical contact with the printed circuit board 15 in the SMD soldering process. The quadrant switch 10 also has an actuating member 18, the pivot bearing 19 of which and the actuating arms 20 of which are arranged inside the housing 11 and the actuator 21 of which penetrates the cover 13 of the housing 11. Four actuating arms 20 are provided which are arranged with uniform spacing round the pivot bearing 19 formed as a sphere so as to project radially and point in the direction of the diagonals of the rhombic housing 11. The longitudinal axes of the radial actuating arms 20 intersect at a point 22 which is also intersected by the longitudinal axis of the actuator 21 and forms the centre of the spherical pivot bearing 19. Each actuating arm 20 has an axial blind hole 23 in which a pressure spring 24 is mounted and in the opening of which a latching element in the form of a latching sphere 25 is arranged. Therefore, the pressure spring 24 is located between the inner end of the blind hole 23 and the latching sphere 25. Therefore in the embodiment, the actuating arms 20 are each arranged at 90° and so as to be uniformly distributed over the periphery of the spherical pivot bearing 19 and so as to be directed along the housing diagonals. The pivot bearing 19 is pivotably held (in the four directions) between annular spherical bearing shells 26 on the pot-shaped main component 12 and correspondingly shaped bearing shells 27 on the cover 13. The bearing shell 26 is arranged integrally on the base 28 of the pot-shaped main component 12. The bearing shell 27 is located at the inner end of a funnel-shaped peripheral wall part 29 of the cover 13. The funnel-shaped wall part 29 integral with the cover 13 is arranged centrally in the cover and forms a funnel-shaped recess 31 tapering from the outside in, which is penetrated by the actuator 21 of the actuating member 18. The funnel-shaped recess 31 offers the actuator 21 sufficient pivotability in the four diagonal directions of the rhombic or square housing 11 which can be seen in Fig. 2. At the same time the funnel-shaped wall part 29 forms the pivot limit for the actuator 21 for these directions. The region of the funnel-shaped wall part 29 projecting above the exterior of the cover 13 is provided with a peripheral groove 32 in which a sealing diaphragm 33 is held, the other inner periphery of which is held in a groove 34 of the actuator 21. The cover 13 is held in corresponding grooves 37 of the pot-shaped main component 12 by strips 36 formed at the corners and is also supported by an annular face 38 on an inner step 39 of the pot-shaped main component 12. A connecting link path 41 is provided in this interior region forming the transition between cover 13 and pot-shaped main component 12 for the latching sphere 25 of each actuating arm 20, which path is divided into an upper path part 42 provided on the interior of the cover 13 and a lower path part 43 provided on the interior of the pot-shaped main component 12. The connecting link path 41 is concave in design viewed in longitudinal section, the lowest region or the region of the connecting link path 41 furthest removed from the centre 22 being located at the transition from the upper to the lower path part 42, 43 and determining the neutral position of the actuating member 18 according to Fig. 1. The pressure spring 24 is designed and pre-tensioned in such a way that it always presses the latching sphere 25 against the connecting link path 41 and, for example according to Fig. 1, into the latching trough 44 determined by the deepest point. The upper path part 42 of the connecting link path 41 is determined by a substantially plane oblique face, whereas the lower path part 43 of the connecting link path 42 is determined by a curved or convex face. The arrangements of the two path parts 42, 43 and their course also determine the actuating force of the quadrant switch during the pivoting movement of the actuating member 18. The contact elements are arranged on the base 28 of the pot-shaped main component 12 and, more precisely, a stationary contact 46 and a movable contact 47 are arranged in each diagonal corner region. The movable contact 47 which is placed and held on the base 48, consists of a plate-shaped part 48 with a central recess 49 in which a switching tongue 50 punched out centrally from the stationary plate-shaped part 48 is provided which is bent from the plane of the stationary plate-shaped part 48 at an acute angle toward the interior. The stationary contact 46 placed on the base 28 and secured thereto is located below the movable switching tongue 50 and inside the recess 49. The inner ends 17 of the connecting legs 16 are let into the base 28 of the pot-shaped main component 12 of the housing 11 and are guided toward the relevant regions of the stationary contact 46 and movable contact 47. Two further connecting legs 16' are guided to a stationary annular contact 45 in the base 28 which is located further in and can be used for additional functions. The stationary plate-shaped part 48 of the movable contact 47 and therefore the stationary contact 46 also are each completely covered by a curved switching mat 51 made of silicone. This switching mat 51 rests with its inner annular front on the plate-shaped part 48. A switching transmission cam 52, which rests in the starting or rest position on the deflected free end of the switching tongue 50, is arranged on the interior of the switching mat 51. The bottom side of one of the actuating arms 20 is located, in accordance with Fig. 1, at a specific distance with respect to each switching mat 51 in the rest position. If the quadrant switch 10 is operated, for example, in such a way that the actuator 21 of the actuating member 18 is pivoted from the neutral or central position illustrated in Fig. 1 in the direction of arrow A to the left, the following results during this switching process: upon movement in the direction of the arrow A the latching sphere 25 of the relevant actuating arm 20 moves along the lower path part 43 of the connecting link path 41 while the latching sphere 25 of the diagonally opposite actuating arm 20 moves along the upper path part 42 of this connecting link path 41. The two latching spheres 25 are pressed against the pressure springs 24 in the process which means that to actuate the quadrant switch 10 a certain actuation force has to be overcome. This actuation force, which increases along the lower path part 43, is then at its largest when the latching sphere 25 is located in the zenith of the convex lower path part 43, in which position the bottom side of the actuating arm 30 touches the top side of the opposing associated switching mat 51 but does not yet push it downward. Upon further movement in the direction of the arrow A the actuating force decreases owing to the course of the convex lower path part 43, wherein the switching mat 51, however, is pressed in the direction of the base 28. In the process the switching transmission cam 52 of the switching mat 51 moves the free end of the switching tongue 50 in the direction toward the stationary contact 46. When the actuator 21 has reached the opposing inner wall of the funnel-shaped wall part 29 the pivoting movement process is concluded and the switching tongue 50 pressed with its free end onto the stationary contact 46, so the contact is closed. During this pivoting movement the latching spheres 25 of the two actuating arms extending perpendicular to the aforementioned actuating arms 20 remain in their associated latching trough 44 in which the latching spheres 25 rotate only about the axis of the actuating arm. Fig. 4A and 4B show variations of the quadrant switch 10 according to Fig. 1 to 3, wherein the variations do not, however, refer to the described switching process. For example, Fig. 4A and 4B show the mechanical clipping-in of a housing 11 in openings of the printed circuit board 15 by hook-shaped feet 14'. Fig. 4A also shows a light guide 56 which penetrates the hollow actuator 21 and at its inner end remote from the end projecting from the actuator 21 is connected to a LED 58 shown by dot-dash lines in Fig. 1 which is arranged below the base 28 of the housing 11 remote from and connected to the annular contact 45. Fig. 4B shows an actuating rod 57 which penetrates the hollow actuator 21 and which is connected at its inner end remote from the end projecting from the actuator to a pushbutton switch 59 shown by dot-dash lines in Fig. 1, or the like, which is electrically connected to the annular contact 45. In this way a fifth contact arrangement can be closed and opened by axial actuation of the rod 57.

Claims: Electric switch (10), in particular quadrant switch, with a plastics material housing (11) in which stationary and movable contact elements (46, 47) are mounted, with an actuating member (18) which, for actuation of the movable contact elements (46, 47), is held in the plastics material housing (11) in such a way that it is pivotable from a neutral position in preferably four actuating directions, the actuating member (18) having an actuator axis (21) and radially projecting actuating arms (20), and with components (24, 25, 41) causing the readjustment and sustained adoption of the neutral position by the actuating member (18), characterised in that a switching transmission mat (51) which at least overlaps the movable contact element (47) is provided between the contact elements (46, 47) and the actuating arm (20) of the actuating member (18) for the switching movement transmission and in that the actuating arm (20) is provided at its free end with an axially projecting and axially operative spring-loaded latching element (25) which, during actuation, is guided along a connecting link (41) being provided in an interior axial region of the housing (11) and which, in the neutral position of the actuating member (18), has a latching face (44). Switch according to claim 1, characterised in that the movable contact element (47) is formed by a stationary metal contact base (48) of specific area and a switching tongue (50) punched out approximately centrally from the base and inclined at an acute angle and in that the switching mat (51) overlapping the contact base (48) is curved and provided on the inside with an actuating cam (52) remote from the free end of the switching tongue (50). Switch according to claim 2, characterised in that the stationary contact element (46) is arranged in the region of a recess (49) of the contact base (48) of the movable contact element (47), which recess is also formed by the switching tongue (50). Switch according to at least one of claims 1 to 3, characterised in that the connecting link (41) for each actuating arm (20) is formed by two mutually opposed connecting link paths (42, 43) which extend toward one another at an angle from two axial directions. Switch according to claim 4, characterised in that the region of meeting of the two connecting link paths (42, 43) is provided with an indent (44), the shape of which corresponds approximately to the shape of the free end of the latching element (25). Switch according to claim 4 or 5, characterised in that the connection link path (42, 43) has surface regions of varying steepness. Switch according to at least one of the preceding claims, characterised in that the actuating arm (20) is provided with an axial hole (23) in which a pressure spring (24) is held and in the opening of which the latching element (25) is arranged. Switch according to at least one of the preceding claims, characterised in that the latching element is formed by a latching sphere (25). Switch according to at least one of the preceding claims, characterised in that the plastics material housing (11) has a pot-shaped receiving part (12) and a cover (13). Switch according to one of claims 4 to 6, and according to claim 9, characterised in that the one connecting link path (43) is formed on the receiving part (12) and the other connecting link path (42) is formed on the cover (13). Switch according to claim 9, characterised in that the cover (13) of the housing (11) is provided centrally with funnel-shaped wall regions (29) which limit the deflection of the actuating member (18) during the pivoting actuation movement. Switch according to at least one of the preceding claims, characterised in that the actuating member (18) is provided with a spherical bearing (19) which is movably held in corresponding bearing shells (26, 27) of the plastics material housing (11) and from which the actuating arms (20) project radially. Switch according to claim 12, characterised in that the axes of the actuating arms (20) intersect in the centre (22) of the spherical bearing (19). Switch according to claim 12, characterised in that the bearing shells (26, 27) are provided in the receiving part (12) and in the cover (13) of the housing (11). Switch according to at least one of the preceding claims, characterised in that a sealing collar (33) is arranged between actuator axis (21) and cover (13). Switch according to at least one of the preceding claims, characterised in that the contact elements (46, 47) are guided out of the plastics material housing (11) by connecting legs (16). Switch according to at least one of the preceding claims, characterised in that the actuator axis (21) has an axial through-hole, an LED or a switch or the like being located on the bottom side of the housing (11) and remote from the inner output end of the through-hole and in which a light guide (56) is received or a switch actuating pin (57) is held so as to be axially movable.

Inventors: HEEB ALFRED, JANNIERE ALAIN, HEEB, ALFRED, JANNIERE, ALAIN
Applicants: ITT MFG ENTERPRISES INC, ITT MANUFACTURING ENTERPRISES, INC.
Application year: 2001
Main classification: H01H25
IPC codes: G05G9, H01H25