JP2831507B2 - Push button switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push-button switch having a click feeling, which is turned on by utilizing the buckling operation of an elastic member such as a coil spring which is incorporated in a housing at an angle.

[0002]

2. Description of the Related Art As this type of push button switch, conventionally,
Japanese Patent Application Laid-Open No. 60-81719 and Japanese Utility Model Application Laid-Open No. 2-80929.
As disclosed in Japanese Unexamined Patent Application Publication No. H10-260, there is known a configuration in which a coil spring incorporated with a slight inclination in a housing buckles to rotate an actuator, and the actuator turns on a switching element such as a membrane switch. ing. That is, both ends of the coil spring are fixed to the stem and the actuator, and when the operator pushes the stem by a predetermined stroke to compress the coil spring by a predetermined amount, the coil spring disposed at an angle buckles, Since the actuator follows the buckling operation and rotates, the movable contact of the switch element is pushed into the actuator and comes into contact with the fixed contact. And
Since the click feeling is generated when the coil spring buckles, the operator can feel the switching to the switch-on state with his / her finger.

Further, when the pushing operation force on the stem is removed in the switch-on state, the stem rises to the initial position along the housing due to the return force of the buckled coil spring, and the actuator moves when the buckling occurs. Rotates in the opposite direction so that the switch element returns to the off state.

As described above, the push-button switch that switches on by buckling the coil spring has an advantage that a good click feeling can always be obtained.

[0005]

However, in the above-mentioned conventional push button switch, the buckling operation of the coil spring must be converted into the rotation operation of the actuator, and the movable operation of the switch element is reliably performed by the rotation operation. However, since the fixed contact must be brought into contact with the fixed contact, the structure becomes complicated and the cost must be increased.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a push button switch which can ensure high reliability with a simple structure and has a good click feeling.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a housing having fixed contacts disposed on an inner surface thereof, and an elastic buckling which is disposed in the housing at an angle to perform elastic deformation including buckling. A member, a stem that is vertically movable with respect to the housing and is urged in the ascending direction by the elastic buckling member, and is disposed between the fixed contact and the elastic buckling member and has flexibility. At least a portion facing the fixed contact is provided with a contact sheet made of a conductive material, and the elastic buckling member at the time of buckling is configured to urge the contact sheet toward the fixed contact. You.

[0008]

According to the above means, if the contact sheet is bent at the buckled portion of the elastic buckling member, the contact sheet can be reliably brought into contact with the fixed contact, so that the contact sheet functions as a movable contact. A highly reliable push button switch can be obtained, and at least the actuator can be omitted as compared with the conventional push button switch using the buckling operation of the elastic member. Therefore, dust can be prevented from entering the contact portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a push button switch according to the present invention will be described below with reference to FIGS. Here, FIG. 1 is a cross-sectional view of the push-button switch when it is not operated, FIG. 2 is a cross-sectional view of the push-button switch when it is pressed, and FIG. 3 is a main part showing a mounting structure of a rubber molded product incorporated in the push-button switch. FIG. 4 is a cross-sectional view, and FIG. 4 is a perspective view of a main part showing a mounting structure of a metal terminal incorporated in the push button switch.

The push button switch shown in these figures has a housing 1 made of a synthetic resin material, a rubber molded product 2 mounted and fixed on the inner bottom surface of the housing 1, and a bending process in a substantially U-shape. A pair of metal terminals 3 and 4 having both ends protruding below the housing 1 with a square wire, and a position facing the upper surface of the rubber molded product 2 by a flexible member formed by printing a conductive pattern on a resin film. A contact sheet 5 installed in the housing 1, a coil spring 6 that is disposed inclining above the contact sheet 5 in the housing 1 and performs elastic deformation including buckling, and a coil spring 6 that can move up and down with respect to the housing 1. When the stem 7 is pushed downward by a predetermined stroke against the spring force of the coil spring 6, the coil spring 6 compressed by a predetermined amount buckles downward, The buckled portion 6a of the coil spring 6 is located at the center of the contact sheet 5. The so that the push downward.

As shown in FIG. 3, the rubber molded product 2 includes an insulating rubber portion 8 made of silicon rubber and a conductive rubber material obtained by kneading a conductive powder into silicon rubber. It is a molded product in which a pair of conductive rubber portions 9 and 10 arranged side by side on the insulating rubber portion 8 with the central portion interposed therebetween is a molded product, and is a thin portion 9a of each conductive rubber portion 9 and 10. , 10a
Metal terminals 3 and 4 are pressed into contact with each other. That is, the substantially U-shaped metal terminals 3 and 4 respectively protrude downward from the housing 1 as shown in FIG. 4 with the central portions thereof pressed against the thin portions 9a and 10a of the conductive rubber portions 9 and 10. The metal terminals 3 and 4 attached to the housing 1 are twisted by about 90 degrees to twist the portions to be fixed. , 10 are maintained, and the rubber molded product 2
The terminal itself is sandwiched between the metal terminals 3 and 4 and the housing 1. The terminal protruding portion 1a of the housing 1 from which the metal terminals 3 and 4 protrude is formed in a substantially V-shape to prevent the flux from rising.

One end of the coil spring 6, which is an elastic buckling member, is fixed to the stem 7, while the other end thereof is in contact with the peripheral edge of the positioning projection 1b in the housing 1, but is fixed. The housing 1 supports the end in an unfixed state. Therefore, when buckling, as shown in FIG.
The end of the coil spring 6 can rotate around the positioning protrusion 1 b in a direction away from the housing 1, whereby a large buckling operation of the coil spring 6 is guaranteed. The buckled portion 6a of the coil spring 6 that has buckled downward deflects the center of the contact sheet 5 toward the rubber molded product 2 as shown in FIG. The conductive rubber portions 9, 10 in contact with the thick portions 9 b, 10 b of the conductive rubber portions 9, 10 are brought into conduction through the contact sheet 5. That is, in this push button switch, the thick portions 9b and 10b of the conductive rubber portions 9 and 10 are formed as fixed contacts, and the contact sheet 5 is used as a movable contact which comes into contact with and separates from both fixed contacts.

Furthermore, at the center of the bottom surface of the stem 7,
A buckling forcible protrusion 7a is provided which comes into contact with the buckling portion 6a of the coil spring 6 at the time of the descending operation. The buckling operation of the coil spring 6 is forcibly started by being pushed downward by the protrusion 7a. Has become.

Reference numeral 11 in the drawing denotes a printed circuit board on which the push button switch is mounted, and metal terminals 3 and 4 are soldered to a circuit pattern of the printed circuit board 11.

Next, the operation of the push button switch will be briefly described.

At the time of non-operation shown in FIG. 1, the pair of conductive rubber portions 9 and 10 in the housing 1 are kept in the switch-off state because they are insulated from each other. When the contact sheet 5 is pushed downward, the coil spring 6 buckles at the point when the predetermined stroke is pushed, and a click feeling is generated. Immediately thereafter, the contact sheet 5 pushed into the buckling portion 6a of the coil spring 6 as shown in FIG. Is bent and abuts on a pair of conductive rubber portions 9 and 10, and both conductive rubber portions 9 and 10
Are turned on through the contact sheet 5, so that the switch is turned on. At this time, the operator can feel the switching to the switch-on by the click feeling transmitted to the finger.

When the pushing operation force on the stem 7 is removed in the switch-on state, the buckled coil spring 6 returns to the state shown in FIG. 1 by its own restoring force. The switch is turned off after being separated from the conductive rubber portions 9 and 10, and the stem 7 moves up to the initial position along the housing 1 by the return force of the coil spring 6.

As described above, in the above embodiment, if the contact sheet 5 is bent at the buckled portion 6a of the coil spring 6, the contact sheet 5 can be reliably brought into contact with the conductive rubber portions 9, 10. Thus, a highly reliable push button switch using the contact sheet 5 as a movable contact is obtained. Further, since the actuator can be omitted as compared with the conventional product utilizing the buckling operation of the coil spring, there is an advantage that the structure can be simplified. In addition, since the contact sheet 5 is provided at a position covering the rubber molded product 2, it is possible to prevent dust from entering the contact portion, thereby increasing reliability.

The above embodiment employs a movable support structure in which the housing 1 supports one end of the coil spring 6 in a non-fixed state, and the end is not restrained by the housing 1 when buckling. With such considerations, the coil spring 6 can be largely buckled, so that an extremely good click feeling can be obtained.

Further, in the above embodiment, when the stem 7 is pushed in a predetermined stroke, the buckling forcible projection 7a forcibly starts the buckling operation of the coil spring 6, so that the coil spring 6
Even if there is some variation in the spring constant, the buckling can be surely buckled, and the variation in the on-timing is small.

Further, in the above embodiment, since the conductive rubber portions 9 and 10 of the rubber molded product 2 are used as fixed contacts,
The rubber molded article 2 has an advantage that the impact of the buckling of the coil spring 6 is reduced, and it is possible to avoid the occurrence of spark which is a concern when connecting and separating metals.

In the above embodiment, a coil spring is used as the elastic buckling member. However, an elastic member such as a leaf spring may be disposed in the housing at an angle and buckled.

In the above embodiment, the contact sheet is formed by printing a conductive pattern on a resin film. However, another member having flexibility and conductivity such as a thin metal plate may be used as the contact sheet. Good.

[0024]

As described above, according to the present invention, a contact sheet is bent by buckling an elastic buckling member such as a coil spring, and the contact sheet functions as a movable contact. An excellent effect is obtained that the structure can be simplified while ensuring the contact stability of the contact portion, and that the contact sheet covering the fixed contact can prevent dust from entering the contact portion. In addition, if the fixed contact is formed by using the conductive rubber, the impact at the time of buckling of the elastic buckling member can be reduced, and the effect of improving operability and extending the service life can be achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view when a push button switch according to an embodiment is not operated.

FIG. 2 is a cross-sectional view when the push button switch is pressed.

FIG. 3 is a sectional view of a main part showing a mounting structure of a rubber molded product incorporated in the push button switch.

FIG. 4 is a main part perspective view showing a mounting structure of a metal terminal incorporated in the push button switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Rubber molded article 3.4 Metal terminal 5 Contact sheet 6 Coil spring (elastic buckling member) 6a Buckling part 7 Stem 9,10 Conductive rubber part (fixed contact)

Claims (2)

(57) [Claims] 1. A housing having fixed contacts disposed on an inner surface thereof, an elastic buckling member disposed at an angle in the housing and performing elastic deformation including buckling, and a vertically movable member capable of moving up and down with respect to the housing. A stem urged in the ascending direction by the elastic buckling member, and a portion disposed between the fixed contact and the elastic buckling member and having flexibility and facing at least the fixed contact from a conductive material. A push button switch comprising: a contact sheet comprising: an elastic buckling member which urges the contact sheet toward the fixed contact when buckling; 2. The push-button switch according to claim 1, wherein said fixed contact is made of conductive rubber.