The present invention relates to a micro-switch and particularly to a labor-saving micro-switch to perform switching through a lever principle.
Micro-switch provides many advantages such as smaller size and withstanding depressing for millions of times, thus is widely used on 3C electronic products, home appliances and vehicles. Simply speaking, the micro-switch is a control element to set a circuit ON or OFF. Its structure generally includes a holder and a switch assembly and an operation assembly located in the holder. The switch assembly includes a common terminal, a normal-closed terminal and a normal-open terminal. The operation assembly includes a movable member and a pushbutton. The movable member has one end connected to the common terminal. The pushbutton is moved up and down to allow another end of the movable member to sway between the normal-closed terminal and normal-open terminal to switch different connection and conductive states.
A conventional micro-switch such as R.O.C. patent No. 592380 mainly includes an upper lid and a base. The micro-switch also includes a pushbutton, a first pin, a second pin and a conductive reed fastened to the first pin. The pushbutton is depressible downwards onto one end of the conductive reed so that another end of the conductive reed is swayed downwards to connect to the first pin and second pin to generate a switch signal. While it can provide circuit switch function, it relies merely on the conductive reed to bear the downward pressure and provide an elastic force. After used for a prolonged period of time the reed tends to fatigue because of frequent bending up and down and fracture, and result in failure for switching circuit or sending signals.
To remedy the aforesaid shortcoming, China patent No. CN202110987 discloses a micro-switch. Referring to
First, its contact portion is movable reciprocally between a normal position and a triggering position to switch different connection and conductive states, hence the conductive reed must be formed at a length to connect the pushbutton and conductive terminals. Nowadays technology industry generally has a very low gross profit margin in doing business, reducing metal consumption of the conductive reed can help to reduce production cost and improve the gross profit margin of products. Moreover, during operation of the micro-switch, the pushbutton presses the pressed portion to make the contact portion to sway downwards. Since the conductive reed is formed at a certain length, the pushbutton has to be pushed by a sufficient force to make the contact portion to sway a sufficient range to switch to and fro to different conductive states. In addition, a high current is frequently generated when the contact portion and conductive terminals are contacted and the high current could cause heat on the contact surface to melt part of the contact portion and stick to the conductive terminals. To separate the contact portion from the conductive terminals to switch different connection and conductive states requires a greater pressing force. As a result, the sensitivity of the micro-switch deteriorates. Hence there are still rooms for improvement on the conventional micro-switch structure, especially in terms of reducing the production cost and switching different conductive states through a smaller force.
The primary object of the present invention is to overcome the disadvantages of insufficient sensitivity and difficulty in reducing production cost in the conventional micro-switch.
To achieve the foregoing object, the invention provides a labor-saving micro-switch which comprises a housing, a press member located on the housing and a driven member. The housing has a housing compartment inside, a conductive terminal and a common terminal extended outwards from the housing compartment, and an actuation member coupled with the common terminal. The actuation member has a butting portion at one side of the common terminal and a connecting portion at another side of the common terminal. The connecting portion has a first conductive state connecting to the conductive terminal and a second conductive state without connecting to the conductive terminal. The press member is depressible to move reciprocally in a displacement inside the housing between an original position and a pressed position. The driven member is located between the press member and actuation member, and includes a pivotal portion hinged on the housing in a swivelable manner, a force-receiving portion opposite to the pivotal portion in the displacement and a force-applying portion driven by the force-receiving portion to move about the pivotal portion which serves as a fulcrum. The force-receiving portion receives pressing of the press member to drive the force-applying portion to push the butting portion and move the connecting portion to switch between the first conductive state and second conductive state.
In one embodiment the driven member includes a rocking arm connected to the pivotal portion, force-receiving portion and force-applying portion.
In another embodiment the housing includes a holding shaft and the pivotal portion is a sleeve coupled on the holding shaft in a swivelable manner.
In yet another embodiment the housing includes a positioning hole and the pivotal portion is a shaft hinged in the positioning hole in a swivelable manner.
In yet another embodiment the force-receiving portion and pivotal portion are spaced from each other at a distance greater than that between the force-applying portion and pivotal portion.
In yet another embodiment the conductive terminal has two sets to be a first conductive terminal and a second conductive terminal located below and corresponding to the first conductive terminal in the housing compartment of the housing. The connecting portion is connected to the second conductive terminal in the second conductive state.
In yet another embodiment the press member includes a press portion and an elastic element bracing the press portion in normal conditions. The housing includes a channel to allow the press portion to move reciprocally therein, and the press portion has at least one retaining section at the bottom formed at a width greater than that of the channel.
In yet another embodiment the actuation member includes a bracing portion movable about the common terminal serving as a fulcrum to push the connecting portion to connect to the conductive terminal in normal conditions.
In yet another embodiment the housing includes a holder to hold the common terminal and conductive terminal, and a lid to cover the holder.
By means of the structure set forth above, compared with the conventional techniques, the labor-saving micro-switch of the invention provides features as follows:
1. High switch sensitivity. The invention has a driven member located between the press member and actuation member. The driven member includes a pivotal portion hinged on the housing in a swivelable manner, a force-receiving portion opposite to the pivotal portion in the displacement and a force-applying portion driven by the force-receiving portion to move about the pivotal portion serving as a fulcrum. As the press portion takes the force-receiving portion and the pivotal portion respectively as a force applying point and a fulcrum, and the distance between the force-receiving portion and pivotal portion is greater than that between the force-applying portion and pivotal portion, a small force exerting to the force-receiving portion can generate multiplying effect on the force-applying portion, thus users can only exert a small force on the press portion to switch the micro-switch. In another aspect, the sensitivity of the invention also improves.
2. Saving production cost. According to the invention, the press portion drives the actuation member via the driven member and can achieve switching effect without making contact to the actuation member. Hence the actuation member does not need to be formed at a greater length to connect the press portion and common terminal. As a result, the actuation can be made smaller and lighter to save consumption of metal material, and the production cost is lower.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
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As a conclusion, the labor-saving micro-switch of the invention provides a driven member between the actuation member and press member. The driven member includes a pivotal portion hinged on the housing in a swivelable manner, a force-receiving portion opposite to the pivotal portion in the displacement and a force-applying portion driven by the force-receiving portion to move about the pivotal portion serving as a fulcrum. Through such a structure, the press member can drive the connecting portion through the driven member to switch between a first conductive state and a second conductive state. Moreover, the driven member for labor-saving switching can be designed by adopting the lever principle to switch the micro-switch with a small force. The micro-switch thus formed can be used in any electronic devices that require higher sensitivity. In addition, since the actuation is driven by the press member via the driven member, the actuation member does not need to form direct contact with the press member, hence can be made smaller and lighter to reduce usage of metal material and make the production cost lower. It provides significant improvements over the conventional techniques.
While the preferred embodiments of the invention have been set forth for the purpose of disclosure, they are not the limitations of the invention, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.