Patent Publication Number: US-4057698-A

Title: Switching mechanism of a timepiece

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a switching mechanism which is able to be employed in a small-sized electronic watch. 
     Generally, a conventional switching mechanism for electronic watches comprises a winding stem of the type used also in a mechanical watch, a setting lever, a clutch lever and other members actuated by said winding stem. However, the movements of the setting lever, clutch lever and said other members are effected on a horizontal plane when said winding stem is actuated. As a result, the conventional switching mechanism requires a large space within the limited space of the watch because of the horizontal actuation of said members. Further, a switching spring member B as shown in FIGS. 1 and 2 has been proposed, however it is also horizontally actuated by a winding stem A. In this case, there is the same disadvantage as that of above-mentioned mechanism. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to eliminate the above-mentioned drawbacks and to provide an improved switching mechanism which is suitable to be employed in a small-sized electronic watch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 and 2 illustrate conventional timepiece switching mechanisms; 
     FIG. 3 is a partial sectional view of the switching mechanism of the present invention set to an off condition; and 
     FIG. 4 is a partial sectional view of the switching mechanism according to the invention showing the mechanism in an on condition. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will be fully described by way of the illustrated preferred embodiment in connection with the accompanying drawings. 
     Referring to FIG. 3, there is shown a switching mechanism of the present invention where the switching state thereof is set under an OFF condition. The switching mechanism comprises a winding or adjusting stem 1, a minute gear wheel 2, a spring member 3, a movable contact member 4, a base plate(or a bridge) 5, and a circuit block or board 6. The base plate (or bridge) 5 is provided with a hollow first bore 5a for receiving an internal end portion 1a of the winding stem 1. The base plate or bridge 5 is provided with a hole or second bore 5b which crosses said hollow 5a. In the hole 5b of the base plate 5, the movable contact member 4 is slidably inserted. The movable contact member 4 has at one end a center shaft portion 4a for the rotation of the minute wheel 2 while the other end of the contact member 4 has a downwardly extended shaft portion or guide 4b serving as a holding and a guiding portion which is inserted into a hole 6a of a circuit block or insulated printed circuit board 6. In a substantially middle portion of the movable contact member 4 is a hollow transverse bore 4c which exactly corresponds to said hollow bore 5a of the base plate or the bridge 5. The hollow 4 of the contact member 4 has a tapered rim 4d at one side from which the winding stem is inserted therein. 
     When the movable contact member, which is inserted in the hole 5b of the bridge, is supported by the winding stem 1 inserted into the hollow 4c. As shown in FIG. 3, the lower step portion 4e is raised above the circuit board 6. The spring member presses down against the upper end of the movable contact member 4 and biases it together with the minute wheel 2 toward the circuit block 6. A pair of immovable contact members 7, 7&#39;, which may be printed circuit lands on the circuit block 6, are disposed around the extended shaft portion 4b of the movable contact member 4. The immovable contact members 7, 7&#39; disposed around the extended shaft portion 4b are opposed to the step portion 4e of the movable contact member 4, so that an electrical connection between both contact members 7, 7&#39; is effected when the contact member 4 is moved downward to the position shown in FIG. 4 with the step portion 4e of the movable contact member 4 in contact with the faces of the immovable contact members 7, 7&#39;. In this contact position the downward movement of the movable contact member 4 for making electrical contact with the immovable contact members is limited by the printed circuit contact members 7, 7&#39;. 
     Describing next the operation of the switching mechanism according to the present invention, the winding stem 1 shown in FIG. 3 is positioned at a normal or inserted operation position. In this case, since the winding stem is exactly inserted in the lateral bore 5a of the base plate or bridge 5 and the bore 4c of the movable contact member 4, the movable contact member 4 is supported by the winding stem and spaced away from the immovable or stationary contact members 7, 7&#39;. Therefore, there is no electrical connection between both contact members. 
     Referring to FIG. 4, both contact members 7, 7&#39; are contacted by the conductive lower end step portion 4e of the movable contact member 4 which defines a contact surface for contacting the stationary contacts. For this purpose, the winding stem 1 is pulled out to a retracted position so that the end 1a of the stem 1 clears the bore 4c of the movable contact member 4. At this time, the movable contact member 4 which is pressed by the spring member 3 moves downwardly so as to come in contact with the immovable contact members 7 7&#39;, so that the step portion 4e of the movable contact member 4 is in contact with the contact face of the immovable contact members 7, 7&#39;. The spring member 3 attached to the mounting block 8 defines means for biasing the contact member 4 to a lowered position with the contact surface thereof contacting the stationary contacts. In this way the electrical contact between both contact members is effected. By making use of the electrical switching mechanism, the electronic circuit of a watch is able to be reset for stopping the drive the watch indicating hands. In this case, the movable contact member 4 is earthed to the winding stem, base plate or other such mechanical parts. 
     For releasing or opening the electrical contact between both contact members, the winding stem 1 is pushed to an operative position so that the internal end 1a thereof is inserted into the tapered portion 4d of the bore 4c of the movable contact member 4, whereby the tapered portion 4d climbs the end 1a of the stim and the movable contact member 4 is pushed up by the winding stem to disengage from the immovable contact members 7, 7&#39;. As illustrated, the stem 1 is mounted and positioned by the mounting block 8 having a bore 8a aligned with the first bore 5a through the base plate 5, and the stem 1 is slidable between the retracted and the operative position. The mounting block 8 having bore 8a defines mounting means slidably mounting the adjusting stem 1, and its structure is not critical. 
     In the above-mentioned embodiment, as illustrated, movement of the movable contact member is effected by the engagement of the bore of the movable, contact member with the winding stem or the disengagement therebetween, but the invention is not limited to this structure and modifications and changes are possible. For example, the movable contact member may be moved in a square crossing to the winding stem by a cam which has a tapered portion and mounted around the winding stem in such a way that it moves reversely in cooperation with the operation of the winding stem. 
     Further, the switching mechanism according to the present invention is not limited to use in an analog display electronic watch; it may be employed in a digital display electronic watch. 
     Furthermore, it is obvious that it is possible to make several contacts for several switching functions by providing several immovable contact members on opposite sides of the movable contact member or within a shift area of the movable contact member. 
     As mentioned above, the switching mechanism according to the present invention brings about many advantages as follows: since the movable contact member moves vertically relative to the axial movement of the winding stem caused by the pulling or pushing operation of the winding stem, the space of the switching mechanism of the present invention is very small, and the structure of the switching mechanism is very simple and a small-sized electronic watch is obtained.