MULTI-POSITION ELECTRICAL SWITCH

Abstract: The switch comprises a housing (1), an insulating board (2), a plurality of stationary contacts each formed of a pair of film electrodes arranged around a central position on the insulating board, an insulating sheet (31) arranged on the insulating board and having cushions (32a-32h) expanding over the stationary contacts, movable contacts (33a-33h) inside the top of the cushions and forming switch elements with the stationary contacts, and an operation button (34) having pressing surfaces for driving each switch element by pressing said cushions, arranged tiltably and having projections (34i, 34j-34m) arranged on its bottom at positions corresponding respectively to the central position and to intermediate positions between the positions of the cushions for preventing the simultaneous operation of the switch elements.

Description: The present invention relates to a switch adapted to be used as a remote controlling switch for motor-driven rear view mirrors of a motor vehicle. Each of a pair of motor-driven rear view mirrors mounted on a door, a fender or the like, of a motor vehicle has two electric motors or the like, in its driving section, said electric motors or the like being controlled by means of a switch inside the vehicle so as to adjust the direction of inclination, horizontal or vertical, of each mirror. The switch for controlling the motor-driven rear view mirrors is required to have the functions of actuating each of said two electric motors of each mirror independently, and changing the polarity of electric power supply thereto. Also, the switch must be easy to fix in the instrument panel or the like. To meet such requirements, the inventors have already invented a switch which, as disclosed in JP-U-56-71428, comprises a housing, an operation member disposed within said housing at a predetermined clearance from the inner walls of said housing, said operation member being adapted to rock from its neutral position in the directions meeting at right angles with one another, two switch elements disposed between a pair of electrodes via a pressure-sensitive electrically conductive rubber sheet and arranged by two at the four interval positions, and a switch for changing the polarity of a power supply is formed of said switch elements. However, the prior art switch has a deep shape and cannot be made small because the operation member is rockably disposed within the housing and the switch elements are disposed between the operation member and the four inner walls of the housing. Also the switch is not very easy to fix in the instrument panel. Furthermore, it does not provide sufficient assembling property and a good feeling of use because the operation member has almost no stroke and does not click at all. The known prior art comprises JP-U-54-169,775 which relates to an operation button provided with projecting push buttons and JP-U-56-17 635 disclosing contact elements in the form of crest shape. It also comprises US-A-3 399 287 which relates to a switch comprising a base member, an operation button mounted for rocking movement relative to the base member, a plurality of contacts provided on the base member and operation button in confronting cooperation relation, and interlock means for preventing simultaneous operation of more than an intended number of contacts, said interlock means comprising a plurality of spaced barriers of predetermined height located between and in alignment with the contacts on the base member to engage the operation button during a rocking movement thereof in a manner to prevent engagement of more than an intended number of contacts. The present invention relates to a switch comprising means for preventing the simultaneous operation of contacts, which are quite different from the interlock means disclosed in US-A-3 399 287 and constitute a concept quite different from the known prior art. Indeed, the switch according to the present invention comprises a housing, an insulating board arranged in said housing, a plurality of stationary contact elements, each formed of a pair of film electrodes and arranged around a specific central position on said insulating board, an insulating sheet arranged on said insulating board, formed with cushions of crest shape in section extending in the direction of said stationary contact elements at positions corresponding to the positions of said elements, movable contacts inside the top of said cushions, and forming switch elements with said stationary contact elements, and an operation button provided at its bottom with four pressing surfaces so divided by two diagonal lines that they respectively lie on top of two of said cushions ; said operation button being square shaped and provided in the center and the four corners of its bottom with projections respectively for preventing the simultaneous operation of more than one pressing surface thereof. The present invention will now be described in detail, with reference to the embodiment illustrated in the enclosed drawings showing a switch for controlling motor driven rear view mirrors of a motor vehicle. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view of a multi-position electrically switch according to the present invention, Fig. 2 is an enlarged sectional view taken along the line II-II in Fig. 1, Fig. 3 is a bottom view of the insulating sheet, Fig. 4 is a bottom view of the operation button, Fig. 5 is an enlarged plan view showing the insulating board, Fig. 6 is a plan view showing the relative disposition of the switch elements on the board, and Fig. 7 is a circuit diagram showing the connecting relation of the switch elements. DESCRIPTION OF THE PREFERRED EMBODIMENTS The constitution will be described, and numeral (1) in the drawings represents a housing, (2) a printed board (an insulating board) which operates also as the bottom plate of the housing (1). Disposed within the housing (1) are a switch S₁ forming a switch for changing the polarity of a power supply and another switch S₂ for changing a motor driven mirror. First, the switch S₁ will be described in detail. The switch S₁ comprises, for example, eight switch elements illustrated by A to F′ as shown in Fig. 6. Each pair of printed circuit electrodes (3) a and (4) a to (3) f ′ and (4) f ′, serving as stationary contact elements of the switch elements A to F′, are printed around a specific central position on the printed board (2) in a pectinated shape. The film electrodes (3) a and (4) a to (3) f ′ and (4) f ′ are disposed to occupy the substantially upper and lower, right and left areas of the printed board (2) as a whole (Fig. 5). An insulating sheet (31) is laminated on said stational contact elements. This sheet (31) has cushions (32) a to (32) h of crest shaped in section corresponding to the plurality of stationary contact elements. The cushions are made of rubber integrally with the sheet (31), or they may be made of a different insulating material separately from the sheet (31). Movable contacts (33) a to (33) h are fixed inside the top of the cushions (32) a to (32) h . The movable contacts may be made of a composite material having pressure conductive rubber consisting of silicone rubber and metal particles or they may be metal plates, etc. Thus, according to the present invention, the eight switch elements A to F′ are disposed planely on the printed board (2) and these switch elements A to F′ are connected by printed conductors (6) so as to form two sets of power supply polarity changing switch as connected as required. That is, in Fig. 7, the four switch elements A, B, E and F form one switch means for vertical adjustment to be described later and the four switch elements C, D, E′ and F′ form the other switch means for horizontal adjustment . The arrangement of the switch elements A to F′ on the printed board (2) is illustrated in Fig. 6. Driving mechanism are disposed over said switch elements A to F′ formed as described above. More particularly, an operation button (34) is disposed over the eight cushions (32) a to (32) h of the insulating sheet (31). The operation button (34) is square in its plan view, and the outside of its top is engaged with the corners between the inner walls of the housing (1) and the top plate (1a). Projecting push buttons (34) a to (34) d provided on the top of the operation button (34) protrude upward from openings (1f) provided in the top of the housing (1). As shown in Fig. 4, the operation button (34) is provided at its bottom with four pressing surfaces (34) e to (34) h so divided by two diagonal lines, said pressing surfaces respectively lying on top of two cushions (32) a and (32) b , (32) c and (32) d , (32) e and (32) f , (32) g and (32) g and (32) h . Therefore, the pressing surface (34) e corresponds to the switch elements A and F, the pressing surface (34) f corresponding to the switch elements B and E, the pressing surface (34) g corresponding to the switch elements C and F′, the pressing surface (34) h corresponding to the switch elements D and E′. Thus, the pressing surface (34) e to (34) h of the operation button (34) corresponds to two switch elements. The operation button (34) is provided in the center and four corners of its bottom with projections (34) i and (34) j to (34) m for preventing the simultaneous operation of more than one pressing surface thereof. If two push buttons, for example, (34) a and (34) c or (34) a and (34) d , are pushed with the same force at the same time, the projection (34) i passes through an opening (31) a in the center of the insulating sheet (31) and contacts the board (2) while one of the projections (34) j to (34) m passes through one of notches (31) b and contacts the board (2), so that the switch elements corresponding to two pressing surfaces, for example, F and F′, A and D or F and E′, are not closed at the same time, thus the possibility of the oblique movement of the mirror or short circuit being eliminated. Therefore, the lengths of the projections (34) i and (34) j to (34) m are such that the projections are out of contact with the board (2) when one of the push buttons (34) a to (34) d is properly pushed and corresponding switch elements are closed while the projections come into contact with the board (2) so as to prevent any switch elements from being closed when a plurality of push buttons are pushed at the same time. Reference will now be made to the switch S₂. The switch S₂ is for selectively connecting the above-mentioned switch S₁ with either the right-hand mirror R or the left-hand mirror L and is constructed as follows: The switch S₂ comprises two circuits and six contacts. Contact patterns ℓ , m and 14 a to 14 d , corresponding to the six contacts, are printed near one end (upper portion in Fig. 7 ) of the board (2). A slide block (15), slidable right and left in Fig. 1, is disposed over the contact patterns ℓ , m and a and d . The slide block (15) is provided with movable contacts (16) a and (16) b corresponding to the contact patterns ℓ , m and 14 a to 14 d . A pair of push buttons (17) a to (17) b respectively corresponding to the right-hand mirror R and the left-hand mirror L are disposed on both sides of the slide block (15) in the direction of its slide. The driving end of each push button is engaged with each of taper portions (not shown) formed on both ends of the slide block (15). Thus, the embodiment illustrated in Figs. 1 to 7 is a hybrid switch comprising said switch S₁ including the eight switch elements A to F′ and said changeover switch S₂. Fig. 6 shows a connector for leading (+) and (-) of a power supply and externally leading the contacts 14 a to 14 d , and contact n in the changeover switch S₂ to the exterior (the mirrors R and L). Referring to Fig. 7, symbols M₁, M₂ represent electric motors for horizontally and vertically driving the right-handed mirror R, and M₃, M₄ represent electric motors for vertically and horizontally driving the left-handed rear view mirror L. The operation of the switch of the above embodiment will now be described. Reference will be made to the case of controlling the right-handed rear view mirror R by pushing the push button (17) a of the changeover switch S₂. When the push button (17) a is pushed, the slide block (15) is slid toward the left in Fig. 1 and its movable contacts (16) a and (16) b respectively close the contacts ℓ and (14) a together and the contacts m and (14) c together so that the switch S₁ is connected with the righ-hand rear view mirror R. (See the state in Fig. 7). When the push button(34) a of the operation button is pushed in the predetermined inclining stroke, the cushions (32) a , (32) b are contracted, the movable contacts (33) a , (33) b are pressure contacted with the switch elements A, F, which are closed and the motor M₁ rotates in the positive direction, thereby changing the angle of the right-handed rear view mirror R toward upward direction When the pressing pressure is released, the operation button (34) returns to its neutral position as shown in Fig.2 by the elasticity of the cushions (32) a . (32) b . Such elastic action of the cushions (32) a , (32) b provide a good feeling of clicking. When the push button(34) b of the operation button (34) is pressed, the switch elements B and E are closed and the electric motor M₁ rotates in a reverse direction so as to change the angle of the right-handed rear view mirror R downward. When the push button(34) c of the operation button (34) is pressed, the switch elements C and F′ are closed and the electric motor M₂ rotates in such a direction to change the angle of the right-handed rear view mirror R toward the left. When the push button (34) d of the operation button (34) is pressed, the switch elements D and E′ are closed and the electric motor M₂ rotates in a reverse direction so as to change the angle of the right-handed rear view mirror R toward the right. When the push button (34) b , (34) c or (34) d is pressed, the cushions (32) c and (32) d , (32) e and (32) f , or (32) g and (32) h behave in the same way as when the push button(34) a is pressed. When the push button (17) b of the changeover switch S₂ is pressed, the left-hand mirror L is controlled in the same way as described above. According to the present invention as described above, an insulating board in which stationary contact elements, each having a pair of printed circuit electrodes are arranged in a housing, and cushions provided corresponding to the elements, in which the insulating sheet provided with stationary contact elements and movable contacts forming switch elements and an operation button for operating the switch elements are arranged. The operation button is tiltable and constantly resettable trend by utilizing the elastic force of the cushions. Accordingly, the profile may be formed in flat and thin structure, the number of parts can be reduced with ready assembling work in high reliability in the switch. Particularly in the present invention, it is not necessary to use the expensive pressure-sensitive electrically conductive rubber. Even if it is used, it may be in small amount, thereby reducing the number of parts and largely decreasing the production cost. Since the inclining operation of the operation button is performed by the elastic force of the cushions different from the conventional pivot type, operating feeling is constant, smooth switching operation can be maintained even in use for a long period of time. Consequently, a switch which is ideally adapted as a switch for driving and controlling a motor driven mirror of a vehicle can be provided.

Claims: A switch comprising a housing (1), an insulating board (2) arranged in said housing, a plurality of stationary contact elements (3a-3f, 3e',3f';4a-4f,4e',4f') each formed of a pair of film electrodes and arranged around a specific central position on said insulating board (2), an insulating sheet (31) arranged on said insulating board (2), formed with cushions (32a-32h) of crest shape in section extending in the direction of said stationary contact elements at positions corresponding to the positions of said elements, movable contacts (33a-33h) inside the top of said cushions, and forming switch elements (A-F,E',F') with said stationary contact elements, and an operation button (34) provided at its bottom with four pressing surfaces (34e-34h) so divided by two diagonal lines that they respectively lie on top of two of said cushions ; said operation button (34) being square shaped and provided in the center and the four corners of its bottom with projections (34i, 34j-34m) respectively for preventing the simultaneous operation of more than one pressing surface thereof. The switch as claimed in claim 1, wherein a pair of said switch elements (A-F,E',F') corresponds to one of said pressing surfaces, and said switch elements form two sets of switch means for changing the polarity of an electric power supply.

Inventors: MUTO, TADAYOSHI, NAKAYAMA, KIYOSHI
Applicants: MURAKAMI KAIMEIDO CO., LTD
Application year: 1982
Main classification: H01H13
IPC codes: H01H25