Control Switch For Electric Winch

The present invention relates to a control switch for an electric winch, particularly to an improvement in a structure including a set of push button switches which provide control for the pulling, releasing, braking and stopping of an electric winch.

The coiling and uncoiling of a steel cable of an electric winch are controlled by forward and reverse push buttons of a control switch. The switches change the polarity of the motor so that the motor can either be stopped or rotated in a clockwise or a counter-clockwise direction. In addition, the majority of conventional devices use a clutch and lining plate to complete the control after the cable is used in a lifting operation. However, this type of braking force is large which makes it unsafe to use. This type of electric winch also requires a higher current to operate, and it is easy to damage the unit during high current overload. The inventor of the present invention has developed a control switch mechanism for this purpose and has been granted with U.S. Pat. No. 5,349,148. The control switch disclosed in the patent is a push button having a V-shaped surface. Both edges of the push button are connected to positive and negative polarity circuits so that the winch can be operated to coil or uncoil the cable.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide a control switch for actuating an electric winch to coil or uncoil a cable. The control switch includes a handle, a set of forward and reverse buttons, and a switch box. Two sets of polarized conducting plates are provided inside of the switch box, and are used as connections for the motor and the DC voltage source. In addition, two sliding blocks are also provided to cooperate with the corresponding pushing of the push buttons. Through the use of the retractable springs and the conducting wipers provided inside of the two sliding blocks, and a "push" on the selected forward or reverse push buttons, the sliding blocks can be displaced so that the conducting wipers of the corresponding sliding block and the two sets of polarized conducting plates can be configured into different circuits. Thus rotation of the motor can be controlled for rotation in the clockwise or counterclockwise direction, and the winch cable can be coiled or uncoiled. When the switches are in their normal positions, the two terminals of the motor are connected together, at this time, the principle of a generator applies and the twisting force of the motor is therefore enhanced, thus the braking force of the motor is also strengthened.

The bottom cover 32 of switch 3 is provided with a plurality of holes 322 for receiving screws 3221 which are used to secure the bottom cover in place. Thus, by the handle 1 and push buttons 2 and 2', a control switch for coiling and uncoiling of an electric winch cable is formed, and its operation is shown in FIG. 6. When the push button body 25 is pressed, the push shaft 21 moves the sliding block 35 of the switch box 3 forward. Thus the conducting wipers 381 and 382 come into contact with the aforesaid positive and negative conducting plates 33 and 33' of the DC voltage, or they come into contact with the positive and negative conducting plates of the motor. This configuration permits a selection of different types of circuits, and it also controls the rotation of the motor which allows the cable to be coiled or uncoiled during an electric winch operation.

FIG. 7 shows the normal position, i.e. when the two push buttons are not being pushed, of the related conducting plates inside the switch box 3. In 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'. Since the 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.