The present invention relates to a mirror switch device provided with four switch parts.
FIGS. 12 to 14 show a general mirror switch device 1. In this mirror switch device 1, the upper, lower right and left parts of an operating knob 2 are adapted to be respectively pressed and operated. On the back surface side of the operating knob 2, a substantially rectangular plate shaped pusher 3 (see a two-dot chain line in FIG. 13 and a solid line in FIG. 14) is provided. Further, on the back surface side of the pusher 3, a pressure member unit 4 made of rubber is provided. On the pressure member unit 4, six elastic pressure members 4a to 4f are formed by an integral molding. On the back surface side of the elastic pressure members 4a to 4f, a printed wiring board 5 is arranged. Switch parts 6A to 6F are respectively disposed so as to correspond to the elastic pressure members 4a to 4f. The switch parts 6A to 6F have the same structures. One of them, for instance, the switch part 6C is described. As shown in FIGS. 13 and 14, the switch part 6C comprises a movable contact 6Ca provided on the back surface of the elastic pressure member 4c and fixed contacts 6Cb and 6Cc provided on the printed wiring board 5.
In this switch part 6C, when the elastic pressure member 4c is pressed down, the movable contact 6Ca allows both the fixed contacts 6Cb and 6Cc to be electrically conducted (on) to each other, and when the elastic pressure member 4c is returned, the movable contact 6Ca allows both the fixed contacts 6cb and 6Cc to be disconnected (off) from each other.
When the upper part of the operating knob 2 is pressed and operated, the two elastic pressure members 4a and 4b are pressed down to turn on both the switch parts 6A and 6B. Thus, a mirror motor not shown in the drawing is energized and driven to move a mirror upward. When the right part of the operating knob 2 is likewise pressed and operated, the two elastic pressure members 4c and 4d are pressed down to turn on both the switch parts 6c and 6D. When the lower part of the operating knob 2 is pressed and operated, the two elastic pressure members 4d and 4e are pressed down to turn on both the switch parts 6D and 6E. When the left part of the operating knob 2 is pressed and operated, the two elastic pressure members 4f and 4a are pressed down to turn on both the switch parts 6F and 6A.
However, in the above-described structure, there is a disadvantage in which the number of the switch parts 6A to 6F is increased, and the number of the elastic pressure members is increased. Further, there is an inconvenience in which a certain switch operation is not obtained. That is, for instance, when an eccentric position designated by reference character Ph on the upper side part of the pusher 3 in FIG. 13 is pressed and operated, or when even a central position PO is slantingly pressed or operated, the switch parts 6A and 6B should be naturally turned on, however, the switch parts 6B and 6C are undesirably turned on, or the switch parts 6A, 6B and 6C are undesirably turned on.
The present invention is invented by considering the above-described circumstances and it is an object of the present invention to provide a mirror switch device in which the number of switch parts can be reduced as much as possible, a switch part can be assuredly turned on and the structure of a switch circuit member can be simplified.
The invention relates to a mirror switch device comprising:
a substantially rectangular pusher having four side parts pressed and operated;
first to fourth switch parts respectively disposed at four corner positions of side parts of a rectangular form of the pusher and two of the switch parts corresponding to each side part performing a switch operation when each side part of the pusher is pressed and operated; and
a switch circuit member having the first to fourth switch parts and a plurality of resistances connected together between a pair of terminals and changing a resistance value between the pair of terminals for each of different switch operation patterns of the switch parts in accordance with the pressing operation of each side part of the pusher.
According to the invention, since the switch parts are respectively disposed at the four positions of the corner parts in the side parts of the rectangular form of the pusher, the number of the switch parts can be reduced. In this case, when each side part of the pusher is pressed and operated, since the switch parts are located at both the end parts of each side part, both the switch parts are assuredly pressed and operated to certainly perform a switch operation.
Here, a switch circuit for outputting a signal for moving a mirror upward, downward, rightward and leftward to the four switch parts is required. In the above-described device, since the switch circuit member is provided for changing a resistance value between a pair of terminals for each of different switch operation patterns in accordance with the pressing operation of each side part of the pusher, four resistance value patterns can be obtained between a pair of terminals in accordance with the pressing operations of the four side parts of the pusher. Accordingly, a circuit structure can be made relatively simple.
In this case, the mirror switch device may be constructed in such a manner that the first switch part and the third switch part of the first to fourth switch parts are arranged diagonally and the second switch part and the fourth switch part thereof are arranged diagonally and the switch circuit member comprises a first series circuit connected between the pair of terminals and having the first switch part, a first resistance and the fourth switch part which are sequentially connected; and a second series circuit connected in parallel with the first series circuit and having a second resistance, the third switch part, a third resistance, a fourth resistance and the second switch part which are sequentially connected; and a node between the first switch part and the first resistance in the first series circuit is connected to a node between the third resistance and the fourth resistance in the second series circuit and a node between the first resistance and the fourth switch part in the first series circuit is connected to a node between the third switch part and the third resistance in the second series circuit.
In such a way, the four resistance value patterns can be assuredly obtained from between a pair of terminals in the structure in which two of the four switch parts are selectively turned on.