1. Field of the Invention
The present invention relates to a switch structure applied in push switches, and more particularly to a forward/backward rotation switching mechanism.
2. Description of the Prior Art
“Switch” is a necessary mechanism for electrical equipments and electronic products, such as refrigerators, TVs, extension cords, computers, and video game consoles, all the aforesaid equipments and devices need the switch for turning on/off the power thereof. Push switch is the most conventional used switch.
Please refer to FIG. 1, there is shown a stereo view of a conventional push switch. As shown in FIG. 1, the conventional push switch 1′ is applied in an electric hand-held device for controlling the rotation of a motor, including: a trigger 10′, a sliding mechanism 11′, a first switching shaft 12′, a second switching shaft 13′, negative power connecting member 14′, a supporting member 15′, a connecting member 16′, a positive and negative terminals connecting module 18′, a positive power connecting member 19′, a forward/backward rotation switching mechanism 20′, a compensation type electronic control circuit 21′, a diode 22′, a stop member 17, a first tension spring 24′, a second tension spring 25′, a first cover 231′, a second cover 232′, and a heat-sink 26′.
Continuously refer to FIG. 1, and please refer to FIG. 2, FIG. 3 and FIG. 4, there are shown a stereo view of the positive and negative terminals connecting module, an exploded view of the forward/backward rotation switching mechanism, and an assembly drawing of some parts of the conventional push switch. The positive and negative terminals connecting module 18′ includes a positive terminal 181′ and a negative terminal 182′, used for respectively connecting to a positive terminal and a negative terminal of the motor. In addition, the positive and negative terminals connecting module 18′ further includes a housing 183′ for accommodating the positive terminal 181′ and a negative terminal 182′. The forward/backward rotation switching mechanism 20′ includes a first switching member 201′ and a second switching member 202′, wherein the first switching member 201′ is initially contacted with the connecting member 16′ and the negative terminal 182′, and the second switching member 202′ is initially contacted with the positive power connecting member 19′ and the positive terminal 181′.
In the conventional push switch 1′, the rotation way of the motor can be defined by changing the contact of the first switching member 201′, the second switching member 202′, the positive terminal 181′, the negative terminal 182′, the connecting member 16′, and the positive power connecting member 19′. Moreover, according to the positive and negative terminals connecting module 18′, the forward/backward rotation switching mechanism 20′ further includes: a forward/backward rotation switching stem 205′, a switching stem fixing member 206′, a third compression spring set 203′, and a fourth compression spring set 204′. In which, the forward/backward rotation switching stem 205′ has a rear swing portion 2052′ and a front swing portion 2051′. The rear swing portion 2052′ is provided with a plurality of apertures 2053′ for combining with the first switching member 201′ and the second switching member 202′. Because the front swing portion 2051′ is pivotally connected with the rear swing portion 2052′, the rear swing portion 2052′ would oppositely move after pushing the front swing portion 2052′, such that the contact of the first switching member 201′, the second switching member 202′, the positive terminal 181′, the negative terminal 182′, the connecting member 16′, and the positive power connecting member 19′ can be changed.
Thus, by above descriptions, it is able to know that the conventional push switch 1′ can not only control the rotation of the motor, but also switch the motor to a forward rotation or a backward rotation; However, the conventional push switch 1′ still includes shortcomings and drawbacks as follows:    (1) When being assembled, the first switching member 201′ and the second switching member 202′ are firstly inserted into the apertures 2053′ of the forward/backward rotation switching mechanism 20′, and then the first switching member 201′, the second switching member 202′ and the forward/backward rotation switching mechanism 20′ are directly put on the positive and negative terminals connecting module 18′; thus, because the first switching member 201′ and the second switching member 202′ does not be provided with any locking structures, the first switching member 201′ and the second switching member 202′ may fall out of the apertures 2053′ when the first switching member 201′, the second switching member 202′ and the forward/backward rotation switching mechanism 20′ are directly put on the positive and negative terminals connecting module 18′; that is a main problem when assembling the conventional push switch 1′.    (2) There has no any dust-off or anti-dust mechanism between the rear swing portion 2052′ and the front swing portion 2051′, so that, the external dust would be accumulated in the connection point of the rear swing portion 2052′ and the front swing portion 2051′, and eventually the forward/backward rotation switching stem 205′ cannot be operated normally.    (3) Moreover, in the conventional push switch 1′, although it can pushes the front swing portion 2052′ for easily switching and controlling the motor to make the forward rotation or the backward rotation, the rear swing portion 2052′ may break away from the fixing of the switching stem fixing member 206′ when being subject to an external force, and then the motor cannot be switched and controlled normally.
Accordingly, in view of the conventional push switch still have shortcomings and drawbacks, the inventor of the present application has made great efforts to make inventive research thereon and eventually provided a forward/backward rotation switching mechanism.