BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a control switch for an electric winch cable. More specifically, the present invention relates to a control switch which provides the function of coiling and uncoiling the cable used in the electric winch.
(b) Description of the Prior Art
Conventionally, the control of coiling and uncoiling of an electric winch cable is based on the polarity of the dc voltage applied. After hoisting the heavy object, a clutch is used to operate and control braking. However, such a structure requires a large braking force, and is therefore quite unsafe. In addition, motors used for electric winches are of a high current type, which generally overload and cause damage to the copper wiring.
SUMMARY OF THE INVENTION
The main object according to the present invention is to provide a control switch for controlling the coiling and uncoiling of an electric winch. Conducting plates in the switch are designed to be wide enough so as to be able to handle a motor which draws high current.
Another object according to the present invention is to provide a control switch for an electric winch in which conducting plates for a dc voltage source are arranged to cross each other and a lateral contacting plate is placed in between the two conducting plates. The conducting plates, connected to a motor, are arranged in parallel on two sides of the cover. A push button with a bottom V-shaped surface is used with the conducting plates such that the button can be pressed to the right or left hand side for controlling the polarity of the voltage and the operation of the electric winch. When the switch is off, the twisting force of the motor shaft is increased and the motor is therefore retarded to turn for coiling and uncoiling the winch cable.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings disclose an illustrative embodiment of the present invention which serves to exemplify the various advantages and objects thereof, and are as follows:
FIG. 1 is a perspective view of an assembly of a control switch for an electric winch according to the present invention;
FIG. 2 is a fragmented perspective view of the switch for an electric winch according to the present invention;
FIG. 3 is a perspective view of top cover and bottom cover assemblies of the switch according to the present invention;
FIG. 4 is a front view of the bottom cover assembly of the switch according to the present invention;
FIG. 5A is a cross section the switch according to the present invention;
FIG. 5B is a partially exploded view of a portion of FIG. 5A;
FIG. 6 is a diagrammatic view showing the operation of the switch according to the present invention; and
FIG. 7 is a perspective view of a top cover assembly having two blocking plates on both sides thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIGS. 1 and 2, the switch for controlling the coiling and uncoiling of the electric winch cable according to the present invention mainly consists of a top cover 1, a bottom cover 2, a push button 3, two copper conducting plates A and B used as terminals for 9 dc voltage source, two conducting plates C and D used as terminals for connecting to a motor, and a copper contacting plate E.
The top cover 1 has a hole 11 at its center for a switch knob. Both edges of the hole 11 have a positioning groove in their inner wall. The top cover 1 is of substantially rectangular shape, having a bolt hole 13 opened in each corner thereof. Each of the bolt holes 13 are designed for a bolt 14 to feed through so as to fasten the top cover 1 and the bottom cover 2 together.
The bottom cover 2 is configured to correspond with the top cover 1, having a bolt hole 21 opened in each of the four corners thereof. Each of the bolt holes 21 is used to secure the bottom cover 2 to the top cover 1. The inside surface of the bottom cover 2 has two elongated grooves 22 and 22' at the center and two other elongated grooves 23 and 23' along the two sides.
The center of the bottom cover 2 also has another groove 24 in the lateral direction. Screw holes 221, 221', 2231, 231' are opened at selected ends of each of the four elongated grooves 22, 22', 23 and 23', respectively. Also, in selected locations along both edges there are a plurality of spring positioning holes 25. In addition, the lateral groove 24 also has a spring positioning hole 241 in appropriate locations at both ends thereof
The push button 3 has a top button surface 31 and a V-shaped bottom surface 32. Each side of the push button 3 has a retaining pin 33, and the V-shaped bottom surface 32 has a rabbet 321 on each edge. Each of the rabbet 321 are constructed to receive a copper conducting plate 34, which is secured inside the rabbet 321 by a screw 36. In addition, the V-shaped surface 32 has a plurality of spring positioning holes 37 that correspond to the spring positioning holes 25 of the bottom cover 2. The spring positioning holes 37 are used for the positioning of appropriate springs 38.
The two copper conducting plates A and B, which are used as terminals for a dc voltage source, are fabricated such that the copper conducting plate A is bent horizontally. One end of the copper conducting plate A has a lock hole A1. The other copper conducting plate B is bent horizontally and is also bent down perpendicularly. One end of the copper conducting plate B also has a lock hole B1. The two copper conducting plates A and B are arranged to cross each other to fit into the two elongated grooves 22 and 22' in the bottom cover 2, and they are secured by screws 26 at one end.
The two copper conducting plates C and D, which are mainly used as terminals for connecting to a motor, are substantially flat. First ends of the conducting plates C and D have lock holes C1 and D1. The conducting plates C and D are arranged to fit into the two elongated grooves 23 and 23' in parallel, and screws 27 are used to secure them at their first ends.
The copper contacting plate E is arranged to fit in between the conducting plates A and B, which are crossing each other. The top of the contacting plate E has a supporting post E1 at each end and the bottom has two retaining post E2. Each of the retaining post E2 extends upward and sticks out slightly from the top of the contacting plate E to form a protruded point of contact E21. The contacting plate E is arranged to fit into the lateral groove 24 of the bottom cover 2. Each of the retaining posts E2 has a spring E22 and is movably attached to the spring positioning hole 241 at one end of the lateral groove 24.
In accordance with the aforesaid assembly, the two copper conducting plates A and B, which are used as the terminal for the dc voltage source, can be arranged to cross each other to fit into the central elongated grooves 22 and 22' of the bottom cover 2. The contacting plate E is placed in between the two conducting plates A and B. The conducting plates C and D for the motor are placed inside the elongated grooves 23 and 23' on both sides of the bottom cover 2. The conducting plates A, B, C and D are connected to electrical wire 4 and secured thereto, as is shown in FIGS. 3 and 4. This configuration allows the conducting plates A, B, C and D to have electrical connection with the dc voltage source and a motor 5. Also, springs 38 are loaded into the spring positioning holes 25 of the bottom cover 2 so that the top cover 1, with the push button 3, can be inserted and secured together.
By such configuration, the two retaining pins 33 on both sides of the button 3 butt against the supporting post E1 oil top of the lateral contacting plate E, as shown in FIG. The contacting plate E is now being pushed up by the spring E22 of the retaining post E2, enabling the protruded points of contact E21 of the contacting plate E to make an electrical contact with the conducting plates C and D of the motor. When the push button 3 is pressed to the right or the left hand side, as is shown in FIG. 6, the retaining pins 33 of the button 3 pushes the contacting plate E downward so as to be disengaged from the conducting plates C and D. The two conducting plates 34 on the bottom V-shaped surface 32 of the button 3 form two circuits through which the rotation of the motor 5 can be controlled.
When assembled for use, the control switch according to the present invention for controlling the coiling, uncoiling and stopping of the electric winch cable operates as follows:
1. When the push button 3 is pressed to the right hand side, as shown in the P1 direction in FIG. 6, the retaining pins 33 of the button 3 press the contacting plate E downward such that the contacting plate E disengages from the conducting plates C and D. The conducting plates 34 on one side of the button 3 comes in contact with the conducting plates B, C and A, D of the bottom cover 2, allowing the motor to rotate in a clockwise direction when power is applied. This is the operation of coiling the cable of the electric winch.
2. Similarly, when the push button 3 is pressed to the left hand side, as shown in the P2 direction in FIG. 6, the contacting plate E also disengages from the conducting plates C and D. The conducting plates 34 on the other side of the button 3 comes in contact with the conducting plates C, A and B, D respectively, forming another circuit which allows the motor to rotate in a counter-clockwise direction when power is applied. This is the uncoiling operation of the cable for the electric winch.
3. The push button 3 is snugged by the plurality of springs 38 of the bottom cover 2. When the pressing of the button 3 is released, the switch returns to its "OFF" state. It is in this "OFF" state that the protruded points of contact E21 of the contacting plate E comes in contact with the conducting plates C and D of the motor 5, respectively. The shaft of the motor 5 is now in a brake position. Thus, it is not easy for the external force to turn the motor and cause the danger of uncoiling the cable accidentally. Hence, the safety concern is assured.
In addition, to further assure that the button 3 of the switch will not be accidentally pressed, a shielding plate 15 is added to each side of the button 3 on the top cover 1, as shown in FIG. 7. Thus, the button 3 of the switch is guarded by the shielding plates 15 on both sides and will not be accidentally tripped by external means.