Multi-Position Electrical Switch

1. Field of the Invention

The present invention relates to a switch suitable for use as a remote control switch for electrically operated rearview mirrors of a motor vehicle. More particularly, the invention relates to a switch having switch elements comprising a pressure-sensitive rubber sheet which becomes conductive only when and where it is pressed (hereinafter referred to as a "pressure-sensitive conductive rubber sheet" or a "rubber sheet".

Each of a pair of electrically operated rearview mirrors mounted on a door, a fender or the like, of a motor vehicle contains two electric motors, etc. in its driving section, said electric motors, etc. 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 electrically operated rear view mirrors is required to have the functions of actuating each of said two electric motors of each mirror independently, and of changing the polarity of the electric power supplied thereto.

2. Description of the Prior Art

To meet the above requirements, Kiyoshi Nakayama, one of the inventors, has invented a switch which, as disclosed in Japanese Utility Model application No. Sho 56-71428, comprises a housing, an operating member disposed within said housing at a certain clearance from the inner walls of said housing, said operating member being adapted to swing from its neutral position in four directions meeting at right angles with one another, two switch elements disposed between said operating member and each of the four inner walls of said housing, each of said switch elements comprising a pair of electrodes and a pressure-sensitive conductive rubber sheet disposed therebetween, said switch elements being adapted to change the polarity of the electric power supply.

However, the disclosed switch has a deep shape and cannot be made small because the operating member is swingably disposed within the housing and the switch elements are disposed between the operating member and the four inner walls of the housing. Also, the switch is not very easy to assemble. Furthermore, it does not give a reassuring feeing of use because the operating member has almost no stroke and does not click at all.

U.S. Pat. No. 4,324,472, K. Terada et al. This patent discloses a camera switch for an electrical shutter which can be operated with a soft touch. The switch is made up of an electrode base formed of a flexible printed circuit board, a pressure-sensitive conductive rubber sheet element overlying the printed circuits, and a button with a plurality of projections on its bottom surface. By pressing the button the sheet element is selectively compressed to close the shutter circuit.

U.S. Pat. No. 4,029,915, S. Ojima, describes a keyboard for an electronic computer which keyboard includes a printed circuit board, a contact holder formed of a flexible insulating film and having movable contacts, and keys perpendicular to the printed circuit board but supported to be tilted in a plurality of directions. Four types of switch elements can be selectively actuated by pressing the keys. This structure assumes that any given key is properly tilted when it is depressed.

U.S. Pat. No. 2,857,485, R. Brooks, discloses a multi-position electric switch which through an operating lever, manipulates a wobble disc electrical contact.

The prior art patents do not give any consideration to the problems which arise when a key is incorrectly tilted, as when the corner of a key is depressed, or tilted obliquely, or when two respective switch elements simultaneously could be closed to an ON state.

It is therefore an object of the invention to provide a switch which has obviated all the disadvantages of the prior art. This object has been attained by a switch comprising fixed contact components disposed on an insulating base plate, a pressure-sensitive conductive rubber sheet laid over said fixed contact components, said fixed contact components and said pressure-sensitive conductive rubber sheet forming switch elements, and an operating button adapted to be tilted with respect to said pressure-sensitive conductive rubber sheet and having a tendency to return to its original position.

This and other objects and advantages of the invention will appear more fully from the following description.

FIGS. 1 to 11 illustrate an embodiment of the invention.

FIG. 1 is a plan view of the same.

FIG. 2 is a sectional view taken on line II--II of FIG. 1

FIG. 3 is a plan view of a supporting plate.

FIG. 4 is a bottom view of an operating button.

FIG. 5 is a sectional view taken on line V--V of FIG. 1.

FIG. 6 is a bottom view of a slide block.

FIG. 7 is an enlarged plan view of a printed circuit.

FIG. 8 is a plan view schematically illustrating the arrangement of switch elements in said printed circuit.

FIG. 9 is a circuit diagram illustrating the relations between said switch elements, etc.

FIG. 10 is an enlarged sectional view illustrating a ball-and-socket joint.

FIG. 11 is an enlarged sectional view illustrating the operation of said joint.

The present invention will now be described in detail, with reference to an embodiment illustrated in the drawings.

Numeral 1 represents a housing. Numeral 2 represents an electric insulating base plate of a printed circuit, which plate also serves as a bottom plate of the housing 1. Disposed within the housing 1 is a power source polarity changing switch S1 and another switch S2 for changeover between a right-hand mirror R and a left-hand mirror L.

First, the switch S1 will be described in detail. The switch S1 comprises, for example, six switch elements A to F as shown in FIG. 9. Six pairs of printed circuit electrodes 3a and 4a to 3f and 4f, serving as fixed contact components of the switch elements A to F, are printed on the base plate 2 so that each pair of electrodes is opposed to each other like comb teeth engaged with each other. The complete set of printed circuit electrodes 3a and 4a to 3f and 4f cover an approximately square area on the base plate 2. See FIG. 7.

A pressure-sensitive conductive rubber sheet 5, corresponding to a movable contact of a conventional switch element, is laid over said fixed contact components. The single rubber sheet 5 is common to all the fixed contact components. The pressure-sensitive conductive rubber sheet 5 is made of silicone rubber ahd metal particles, for example. It is usually nonconductive and becomes conductive according to the pressure applied thereto.

Thus, according to the present invention, the six switch elements A to F are disposed on the surface of the base plate 2 and they are connected by printed conductors 6 so as to form two switch means for changing the polarity of the electric power source. That is, in FIG. 9, the four switch elements, A, B, E and F form one switch means (switch means for vertical adjustment) and the four switch elements C, D, E and F form the other switch means (switch means for horizontal adjustment). The two switch elements E and F are common to both of the switch means. The arrangement of the switch elements A to F on the base plate 2 is illustrated in FIG. 8.

Operating means as follows are disposed over said elements A to F.

First, a supporting plate 7 as shown in FIG. 3, formed of an electrically insulating material, is disposed on top of the rubber sheet 5. The supporting plate 7 is fixed at its periphery to the housing 1. And an operating button 11 is supported on a ball-and-socket joint 8 provided approximately in the center of the supporting plate 7 so that the operating button 11 can be tilted with respect to the rubber sheet 5. The operating button 11 has a square shape, for example, in its plan view as shown in FIG. 1, and is adapted to press the rubber sheet 5 separately when any of its four portions, that is, an upper portion 11a, lower portion 11b, left portion 11c and right portion 11d in FIG. 1, is pushed. As shown in FIGS. 2 to 4, the section of the operating button 11 facing the pressure-sensitive conductive rubber sheet 5, that is, the lower part of the button, has the shape of a frustum of a pyramid with its vertex on the vertical axis of said ball-and-socket joint 8 which serves as a point of support, and has four faces 11e, 11f, 11g and 11 h, as well as four corner lines 20 where the faces meet. Each of the four sloping faces 11e to 11h of said frustum of a pyramid has two pressing surfaces, 12a and 12b, 12c and 12d, etc. slightly protruding therefrom. These pressing surfaces 12a to 12h correspond to said switch elements A to F as follows: The pressing surface 12a corresponds to the switch element A, the pressing surface 12b to the switch element F, the pressing surface 12c to the switch element B, the pressing surface 12d to the switch element B, and so on. Thus, each of the four sloping faces 11e to 11h of said frustum of a pyramid corresponds to two switch elements.

Said supporting plate 7, formed of an electrical insulating material, has as shown in FIG. 3, a ball 9, which will be described in detail later, upwardly projecting at the center, and has eight trapezoid-shaped openings 7a spaced radially about the plate. The trapezoid-shaped openings 7a, are surrounded by the periphery 21 of the supporting plate 7, cross member 22 formed in a narrow width from the center toward the periphery and diagonal members 23. Further, a pair of openings 7a and 7a, which form the shape of a trapezoid symmetrical to the respective periphery, cross and diagonal members, correspond to the pressing surfaces 12a, 12b, . . . , 12h which protrude from the bottom section of the operating button. Therefore, when any of the pressing positions 11a, 11b . . . 11d of the operating button is depressed, only a pair of pressing surfaces at the depressed position are engaged with the facing openings 7a and 7a. For example, when the pressing position 11a is depressed, the protruding, pressing surfaces 12a and 12b of the face 11e engage with the facing openings, and when the pressing position is, accordingly, further depressed, thereby pressing the pressure-sensitive conductive rubber sheet 5 at the position, the switch elements A and F at the corresponding positions are, in turn, switched to the ON state.

Said ball-and-socket joint 8 supporting said operating button 11 comprises a ball 9 attached to the supporting plate 7 and a socket 10 provided in the operating button 11. The ball 9 has pins 9a protruding crosswise toward the bottom section of said button. The socket 10 has grooves 10a corresponding to the pins 9a, said grooves 10a being elastic and slightly narrower than the diameter of the pins 9a. The elastic grooves 10a and the pins 9a give the operating button 11 a tendency to return to its neutral, untilted, position.

Reference will now be made to the switch S2 for selectively connecting the above-mentioned switch S1 with either the right-hand mirror R or the left-hand mirror L. The switch S2 comprises two circuits and six contacts. Contact patterns l, m and 14a to 14d, corresponding to the six contacts, are printed near one end (upper portion in FIG. 7) of the base plate 2. A slide block 15, slidable right and left in FIGS. 5 or 7, is disposed over the contact patterns l, m and 14a to 14d. The slide block 15 is provided with movable contacts 16a and 16b corresponding to the contact patterns l, m and 14a to 14d. A pair of push buttons 17a and 17b 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 one of the tapered portions 15a and 15b formed on opposite ends of the slide block 15. Numerals 18a and 18b represent balls for positioning the push buttons 17a and 17b.

Thus, the embodiment illustrated in the drawings is a hybrid switch comprising said switch S1 including the six switch elements A to F and said changeover switch S2.

Numeral 19 in FIG. 2 represents a connector for connecting the contacts l, m and 14a to 14d in the changeover switch S2 with the rearview mirrors R and L. Referring to FIG. 9, Symbol M1 represents an electric motor for vertically adjusting the right-hand mirror R, symbol M2 representing an electric motor for horizontally adjusting the right-hand mirror R, symbol M3 representing an electric motor for vertically adjusting the left-hand mirror L, and symbol M4 representing an electric motor for horizontally adjusting the left-hand mirror L.

The operation of the switch of the invention will now be described.

Reference will be made to the case of controlling the right-hand mirror R by pushing the push button 17a of the changeover switch S2. When the push button 17a is pushed, the slide block 15 is slid toward the left in FIG. 5 and its movable contacts 16a and 16b respectively close the contacts l and 14a together and the contacts m and 14c together so that the switch S1 is connected with the right-hand mirror R. (See FIG. 9.)

When face 11a of the operating button 11 is pushed thereafter for a certain period of time, the switch elements A and F are respectively closed and the electric motor M1 rotates in such a direction as to change the angle of the right-hand mirror R upward. At this time, a corresponding pin 9a of the ball-and-socket joint 8 is forced into a corresponding groove 10a as shown in FIG. 11. When the operator stops pushing the operating button 11, the pin 9a is pushed out of the groove 10a by the elasticity thereof and returns to its neutral position as shown in FIG. 10. Such engagement and disengagement of the pin 9a with the groove 10a cause the operating button 11 to click.

When face 11b of the operating button 11 is pushed, the switch elements B and E are respectively closed and the electric motor M1 rotates in a reversed direction so as to change the angle of the right-hand mirror R downward.

When face 11c of the operating button 11 is pushed, the switch elements C and F are respectively closed and the electric motor M2 rotates in such a direction as changes the angle of the right-hand mirror R toward the left.

When face 11d of the operating button 11 is pushed the switch elements D and E are respectively closed and the electric motor M2 rotates in a reversed direction so as to change the angle of the right-hand mirror R toward the right.

The operation of the ball-and-socket joint 8 when face 11b, 11c or 11d of the operating button 11 is pushed is the same as when face 11a thereof is pushed.

When the push button 17b of the changeover switch S2 is pushed, the left-hand mirror L is controlled in the same way as mentioned above.

As described above, when any of the pressing faces 11a, 11b, . . , 11d of the operating button 11 is depressed, the pressing surface is engaged with the corresponding openings 7a thereby pressing the pressure-sensitive conductive rubber sheet 5. Accordingly, the switch element corresponding to the pressing position is turned ON. In the case where the corner at the pressing position of the operating button 11 is depressed, thereby obliquely operating it, the corner line 20 of the pyramid frustum makes contact with the diagonal member 23 of the supporting plate 7 before the pressing surface engages the openings, with the result that the pressing surface cannot be depressed any further. Consequently, the pressure-sensitive conductive rubber sheet 5 is not pressurized. In other words, when the oblique depression is performed the pressing operation of the rubber sheet is not performed, and accordingly, no switch element is turned ON, thereby completely preventing the short circuiting erroneous operation.

Thus, according to the present invention, the fixed contact components each consisting of a pair of printed circuit electrodes are disposed on the insulating base plate, the pressure-sensitive conductive rubber sheet being laid over said fixed contact components, said fixed contact components and said rubber pressure-sensitive conductive sheet forming the switch elements, and the operating button for operating said switch elements being adapted to be tilted with respect to said pressure-sensitive conductive rubber sheet and having a tendency to return to its original position. Therefore, the switch of the invention can have a flat and thin shape. Also, the switch is easy to assemble and has satisfactory reliability because it consists of a small number of component parts. Consequently, the switch is suitable for use as a remote control switch for electrically controlled rearview mirrors of a motor vehicle.

Furthermore, according to the embodiment of the present invention, the operating button has the shape of the frustum of a pyramid, with its vertex at the point of support thereof, each of the faces of said pyramidal shape having pressing surfaces, said point of support being the ball-and-socket joint having the pins and the elastic grooves. Therefore, the operating button has a tilting stroke and makes clicks. Thus, the switch of the invention is easy to use and gives a reassuring feeling of use.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiment thereof except as defined in the appended claims.