Patent Application
20120193196
The present invention relates to an enhanced returning elasticity micro switch and particularly to a micro switch having enhanced returning elasticity upon being depressed.
Advance of technology has made all kinds of electronic devices (such as mouse) smaller. Electronic elements required by those electronic devices also have to be miniaturized. In the electronic devices, switch is the commonly used electronic element to transmit signals.
References for micro switch are seen in numerous prior arts, such as R.O.C. patent Nos. M350087, 507921 and 289485. R.O.C. patent No. M350087 discloses a micro switch including a housing, a common terminal, a normally-closed terminal, a normally-open terminal, a movable contact plate, a tension spring, a pushbutton and a pressing plate. The pressing plate has a dovetail portion to increase the force receiving area of the housing from the pressing plate to avoid the housing from being pierced through. In addition, the tension spring improves control of received force of the movable contact plate to obtain uniform and agile action force, thereby to further enhance performance and reliability of the movable contact plate.
R.O.C. patent No. 507921 also discloses a micro switch including an upper body and a lower body coupled together, a conduction contact and a fixed contact surface on the top of the lower body, an action member with a fixed end anchored on the fixed contact surface and a movable end fastened to a contact element. When a press element is pressed, the bottom thereof is to push the action member. The movable end of the action member is moved accordingly to allow the contact element to contact with the conduction contact to achieve switch function.
R.O.C. patent No. 289485 discloses a micro switch with a detent rib that has a cap with two protrusive rectangular ribs on the surface to control depression movement of the switch to improve durability.
While all the aforesaid prior arts have varying objectives and functions, they have a common feature. Referring to
However, when the conductive reed 34 is pressed, the first contact portion 341 thereof is not moved downwards to contact the second contact portion 331 of the normally-open terminal 33. In fact, the conductive reed 34 has one end connected with the common terminal to function as a fixed end and generates deformation to swing downwards. The second contact portion 331 of the normally-open terminal 33 is formed in a horizontal structure. After the first contact portion 341 swings downwards to generate angle alterations, the first contact portion 341 and the second contact portion 331 are merely connected at a contact point to transmit electric power between the common terminal 31 and normally-open terminal 33. Such operation generates following problems:
1. The area of power transmission is too small, thus results in higher temperature on the contact point between the first contact portion 341 and second contact portion 331.
2. The first contact portion 341 and the second contact portion 331 have greater attraction between them and generate an adhesive phenomenon, thus results in inadequate returning elasticity of the conductive reed 34.
3. To increase the returning elasticity, the elevation of the second contact portion 331 must be higher, thus the distance between the normally-closed terminal 32 and normally-open terminal 33 is shortened. This causes decrease of withstand voltage.
4. The distance that the conductive reed 34 swings downward is relatively short, and the conductive reed 34 also is braced by an edge of the second contact portion 331, hence pressing resistance increases.
The primary object of the present invention is to solve the aforesaid disadvantages to increase the contact area and enhance returning elasticity of the reed.
To achieve the foregoing object, the invention provides an enhanced returning elasticity micro switch that includes a base, and a first pin and a second pin running through the base. The base has a cap mounted thereon to form a housing compartment between them. The cap has a press element movable up and down. The first pin has an anchor portion in the housing compartment to couple with a conductive member depressed by the press element. The conductive member has a lower contact portion and swings during up and down movement of the press element. The second pin has a first contact located in the housing compartment. The first contact has an inclined surface connected to the lower contact portion during swing of the conductive member. The inclined surface is formed at an elevation tapered towards the anchor portion of the first pin. Moreover, in embodiments of the invention, the contact surface and inclined surface may be plane surfaces or cambered surfaces contacted with each other. The conductive member is a conductive reed and contains an elastic element braced by the anchor portion. The elastic element braces the contact surface escaped away from the inclined surface in normal conditions.
By means of the structure set forth above, the contact area between the conductive member and the second pin increases, the adhesion force between the conductive member and second pin during power transmission can be reduced, and the returning elasticity of the conductive member is enhanced. The resistance against downward depression of the conductive member also is smaller. Hence operation of the micro switch is smoother.
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.
Please refer to
The second pin 22 and third pin 23 have respectively a first contact 221 and a second contact 231 located in the housing compartment 24. The first contact 221 and the second contact 231 are located respectively on the lower side and on the upper side of the conductive member 25 corresponding to the lower contact portion 28 and upper contact portion 27. The first contact 221 has an inclined surface 222 corresponding to the lower contact portion 28 and formed at an elevation tapered towards the anchor portion 211 of the first pin 21.
The conductive member 25 is braced upwards by the elastic force of the elastic element 26 in normal conditions to push the press element 11 upwards, and the upper contact portion 27 butts the second contact 231 of the third pin 23 so that the first pin 21 and third pin 23 are electrically connected (referring to
Thus, by forming the inclined surface 222 on the first contact 221 of the second pin 22, when a user wants to output an operation command or a signal and presses the micro switch, the conductive member 25 is depressed and deformed to swing downwards, and through the lower contact portion 28 contacting the inclined surface 222, the first pin 21 and the second pin 22 are connected through contact surfaces to transmit electricity. Such a structure provides many benefits over the conventional techniques, notably:
1. The area of power transmission is increased, and the temperature at the contact area between the conductive member 25 and second pin 22 also is decreased, thus the lifespan of the micro switch is prolonged.
2. The attraction force between the conductive member 25 and second pin 22 during power transmission decreases, and adhesive phenomenon of the conductive member 25 to the second pin 22 improves, hence returning elasticity of the conductive member 25 is enhanced.
3. Through the inclined surface 222, the downward swinging distance of the conductive member 25 increases, deformation of the conductive member 25 also enhances, and resistance against the depression of the press element 11 decreases. Hence operation is effort-saving and touch feel of pressing the micro switch also enhances.
4. The distance between the first contact of the second pin 22 and the second contact of the third pin 23 increases, thus can withstand a higher voltage test and pass safety approval of greater amperes.
While the preferred embodiments of the invention have been set forth for the purpose of disclosure, 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.
