As shown in FIGS. 1 and a pair of, the current invention includes a handle 1, a set of a forward and reverse push button switches 2, 2′, and a switch box 3.
The handle 1 is formed by two hollow bodies 11, 11′. In a selected location of hollow body 11, two push button holes 111, and 111′ are provided. The push button holes 111, 111′ are provided for receiving push buttons 2, 2′. At a location above the holes 111, 111′, a shielding plate 12 is provided and extends outward for preventing the accidental tripping of the push button switches 2, 2′.
The push button switches 2, 2′ are basically of conventional structure. Each of the switches 2, 2′ include a push shaft 21, 21′, a retractable spring 22, 22′, a removable inner ring 23, 23′, an external protective ring 24, 24′ and a push button body 25, 25′. A base 26 is positioned in the hollow body 11 of the handle and two hollow threaded tubes 261 261′, provided at the front of the base 26, extend through the push button holes 111, 111′ of the hollow body 11. The hollow threaded tubes 261, 261′ are provided in order that the push shaft 21, 21′ may be inserted from the back of positioning base 26. In addition, the removable inner rings 23, 23′ and retractable springs 22, 22′ are inserted from the front of the positioning base 26, and screws 27, 27′ are used for securing the inner rings 23, 23′ to the push shaft 21, 21′. With the retractable springs 22, 22′ in place, an assembly that may be pushed is formed. Also, washers 28, 28′ may be placed between the positioning base 26 and the inner rings 23, 23′ and push buttons 25, 25′ might be secured in place by external protective rings 24, 24′. This forms the assembly of the conventional push button switch.
As shown in FIG. 3, the switch box 3 includes a top cover 31 and a bottom cover 32. Two pairs of slots 311, 311′ and 312, 312′ are provided in the highest cover 31. The wall of the top cover 31 is supplied with corresponding grooves 313, 313′ in addition to notches 314, 314′. The slots 311, 311′ and 312, 312′ are provided such that the corresponding positive and negative conducting plates 33 and 33′ for DC voltage and the positive and negative conducting plates 34 and 34′ for the motor can all be received therein. The conducting plates for DC voltage 33, 33′ have “T” shapes, while the contact portion of the conducting plates for the motor are bent into “U” shapes. Each of the conducting plates are provided with two inwardly facing contact surfaces A, and underneath each contact portion is a positioning stud B. The top of the conducting plates are supplied with screw holes C which are used for receiving screws (not shown) to secure wiring. In addition, the underside cover 32 may be locked together with the highest cover 31. The bottom cover 32 has a surface formed with two grooves 321, 321′. Each of the grooves 321, 321′ is aligned with an opening within the side walls of the bottom cover 32. The side wall opening on one side is further supplied with insertion slots 3211, 3211′. The bottom cover surface can also be supplied with two corresponding blind holes B’, which correspond to the positioning studs B received therein. Also, the aforesaid grooves 321, 321′ are respectively provided for holding sliding blocks 35, 35′. As shown in FIGS. 3, 4 and 5, the sliding blocks 35 (35′) are rectangular hollow bodies having three divided spaces 351, 352 and 353. An inner wall of the forward divided space 351 is supplied with a support post 3511, and the other side of the forward divided space 351 is provided for the attachment of a conducting plate 36. A portion of the conducting plate 36 protrudes outwardly from the sliding block 35 in order that it may be received in the insertion slot 3211 of the groove 321. Also, one end of a retractable spring 37 is positioned over the support post 3511 and the opposite end engages the conducting plate 36. The center space 352 is provided for accommodating two conducting wipers 381, 382. In addition to contact surfaces 3811, 3821, provided on the sides of the wipers, the middle of every conducting wipers 381, 382 is fabricated with a protruding member 3812, 3822. Both ends of a second retractable spring 39 are held in place by engaging the protruding members 3812, 3822. The sliding block 35, when inserted into the groove 321 of the bottom cover 32, could be pushed against the bias of the primary retractable spring 37. Similarly, the other sliding block 35′ has an identical structure. The second sliding block 35′ also includes two conducting wipers 381′ and 382′ in addition to the opposite components (as shown in FIG. 7), and therefore its description just isn’t repeated here.
FIG. 7 shows the normal position, i.e. when the 2 push buttons usually are not being pushed, of the related conducting plates contained in the switch box 3. On this position, the positive and negative conducting plates 34, 34′ connected to the motor are in contact with the conducting wipers 381, 381′ of the sliding blocks 35, 35′. For the reason that positive and the negative terminals of the motor are connected together, the phenomenon of a generator occurs. Thus the twisting force of the motor shaft is increased, which naturally strengthens the braking force of the motor shaft. As shown in FIGS. 8 and 9, the forward button 2 and the reverse button 2′ have been pushed, respectively. Through the conducting wipers 382, 382′ on the other sliding block 35′, the motor can either be connected to the positive or the negative terminals of the DC voltage, allowing the motor to be controlled so as to effect rotation in a clockwise or a counter-clockwise direction. This in turn controls coiling and uncoiling of the electric winch cable.