JPH0422500Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a small switch used as a detection switch for, for example, a VCR cassette/floppy disk.

(B) Prior Art Conventionally, this type of small switch is provided with a conductive coil spring that expands and contracts in conjunction with the depression operation of a plunger, and the coil spring is set as a movable contact for switching operation.

However, one end surface of the coil spring is usually set as the movable contact surface and the movable contact surface corresponds to the contact and separation between the movable contact and the fixed contact. Because the end faces are at right angles, the coil spring tends to tilt in the helical direction when compressed, resulting in unstable contact.Also, burrs and burrs are likely to form on the end faces of this helical wire diameter, resulting in poor contact performance. This has led to problems with low reliability, such as poor contact.

In addition, in order to solve this problem, if the above-mentioned fixed contact is suspended in the air so that the movable contact does not contact other parts (for example, Japanese Utility Model Application No. 52-96279), contact failure of the movable contact may occur. However, the contact area is only the contact area of the fixed contact suspended in the air, and no further contact area can be obtained, and furthermore, the fixed contact suspended in the air due to the pressing force of the plunger This has the problem of deformation and reduced contact reliability.

Furthermore, when forming a double switch, it is necessary to construct two sets of the same switch mechanism within the switch case, which poses the problem that sufficient cost reduction cannot be achieved.

(c) Problems to be solved by this invention Therefore, this invention solves the contact failure when the movable contact is composed of a coil spring, and also makes it possible to obtain a sufficient contact area of the contact and improve the contact reliability of the contact. The purpose of the present invention is to provide a small switch capable of increasing the performance and reducing the manufacturing cost of a double switch.

(d) Means for Solving the Problems This invention holds two plungers on a switch cover at a predetermined interval so as to be able to slide up and down, and the upper surface position of the switch base connected to the switch cover corresponds to the plungers. A spring insertion hole is formed in the switch base, and a conductive coil spring is interposed between the spring insertion hole and the plunger, and a large-diameter coil portion is formed in the intermediate portion and the conductive coil spring is set as a movable contact. A common terminal is inserted at the center of the top surface, and other terminals are inserted at both sides of the common terminal.The outer end of each terminal extends outward from the switch base, and the inner end of each terminal is
A fixed contact is formed by being exposed on the upper surface of the hole edge, with the common terminal side and the other terminal side facing each other across the spring insertion hole, and at a position corresponding to contact and separation with the large diameter coil portion of the coil spring; A small switch is characterized in that each of the fixed contact portions has a contact portion that slightly protrudes from the contact surface.

(E) Function The small switch of this invention has a coil spring compressed when the plunger is pressed down.
The movable contact of the large-diameter coil part moves downward and contacts the contact part of the fixed contact to conduct electricity, and as the movable contact moves downward, the movable contact that contacts the contact part tilts and is exposed.The contact surface of the fixed contact The common terminal and other terminals are thereby electrically connected via the coil spring.

Note that when the plunger is released and the movable contact of the coil spring moves upward and the contact is released,
The above-mentioned conduction becomes non-conduction.

(f) Effects of the device According to this device, a local contact portion that slightly protrudes from the contact surface is provided on the fixed contact side that contacts and separates from the movable contact. The end faces of the coil springs make sure contact, and stable contact can be obtained regardless of the inclination when the coil spring is compressed or burrs or burrs on the end faces of the coil springs. , the inclined portion contacts the fixed contact, increasing the contact area of the contact, making it possible to obtain a sufficient contact area and improving contact reliability.

In addition, since the contact part on the fixed contact side is only partially protruded, it has good workability and can be easily manufactured.Moreover, the contact part is attached to the exposed contact surface of the fixed contact. Because of this, it does not deform even when the pressing force of the plunger is applied, achieving high contact reliability.

Furthermore, since the common terminal is common to both switch mechanisms, the structure can be simplified, and a small double-A contact type switch can be easily produced, leading to cost reductions.

(g) Example of the invention An example of the invention will be described below in detail based on the drawings.

The drawings show a small switch, and in FIGS. 1 to 4, this small switch 11 is formed into a rectangular shape by a switch cover 12 made of synthetic resin and a switch base 13, and the upper surface in the longitudinal direction is At the left and right positions, two plungers 14, 14 for performing a switching operation protrude and hold so as to be able to slide up and down, and on one longitudinal side of the switch base 13, a common terminal 15 as a fixed contact and other terminals are held. 16, 16 are extended outward, and 2 are inside.
A continuous a-contact type switch mechanism 17 is formed.

The above-mentioned switch cover 12 and switch base 1
3 means force fitting between the vertically opposing sides,
Fitted together. Of these, switch base 1
3, a common terminal 15 located in the center and a pair of other terminals 16, 16 located on both sides thereof are insert-molded in a form exposed on the upper surface of the switch base 13, and these terminals 15, 16, 16 are teeth,
A pair of left and right spring insertion holes 1 formed on the top surface
These common terminals 15 and other terminals 16 are disposed on the upper surface of each of the open portions 8 and 18 in such a manner that they face each other.

In this case, both terminals 15, 16, 15, facing each other across the center of each spring insertion hole 18, 18,
16, there is a contact portion 1 having an M-shaped cross section that slightly protrudes from each contact surface, as shown in FIG.
9... is formed locally protruding, and this contact portion 19 has a
Coil springs, which will be described later, are provided in local contact to obtain a reliable contact action.

The above-mentioned switch mechanism 17 is connected to the above-mentioned plunger 1.
4 and each terminal 15, 16, 16 as a fixed contact
and a coil spring 20 as a movable contact made of a conductive material, and the coil spring 20 has a large-diameter conical coil part in the upper part and a small-diameter cylindrical coil part in the lower part. As a result, a large-diameter movable contact portion 21 is provided at the middle portion of the coil.

In this case, by providing it in the large-diameter coil portion of the conical body, the wire rods are prevented from overlapping each other in the compression direction during compression, and a long pressing stroke in the compression direction is provided.

Then, the lower small-diameter coil portion is inserted into the spring insertion hole 18 described above, and the inserted lower end is
An upper spring seat on the lower surface of the plunger 14 is fitted and supported by a lower spring seat 22 protruding from the bottom of the insertion hole 18, and the upper end of the upper large-diameter coil portion extends vertically through the switch cover 12 to allow vertical movement. 23, and normally this coil spring 20 is in a state of being compressed by a certain amount between the upper and lower parts, and the movable contact part 21 in the middle part is connected to both terminals 15 and 16 facing below. It is in an open state without contacting the contact parts 19, 19.

As the plunger 14 moves downward, the coil spring 20 is compressed, and the movable contact portion 21 moves downward and comes into contact with the upper surfaces of the contact portions 19, 19 of both terminals to establish electrical conduction.

Further, the downward movement of the movable contact portion 21 causes the contact portion 19,
The movable contact portion 21 in contact with the contact portion 19 is tilted and comes into contact with the contact surface of the exposed fixed contact portion.

Thereby, the common terminal 15 and the other terminals 16 are electrically connected via the coil spring 20.

In the figure, 24 is a lower large diameter portion for preventing the plunger from slipping out.

FIG. 6 shows a circuit of a small switch composed of a double a-contact type.

In the small switch configured in this way, the coil spring 20 moves downward while being compressed in conjunction with the pressing operation of the plunger 14, and based on this compressed operation, the movable contact portion 21 in the intermediate portion is moved downwardly at both ends. Contacting the contact portions 19, 19 on the top surface of the child, both terminals 15,
16 are electrically connected and become closed.

In this case, even if there are burrs or burrs on the coil spring end face during contact, or even if the contact action is tilted due to the influence of the helical angle during compression, the locally protruding contact portion 19 can be used reliably. Since a local contact effect can be obtained, unstable contact will not occur.

When the plunger 14 is released, the plunger 14 receives the restoring force of the coil spring 20 and returns to its original upward movement position, and the movable contact portion 21 also moves upward and separates from the contact portion 19. It becomes open.

In addition, the coil spring 20 is further compressed to sufficiently absorb the remaining pressing force after the contact has been made, resulting in a long pressing stroke and overtravel, and a good operating feel when operating the switch.

When installing this small switch 11 to a device, the lower surface engaging protrusion 25 protruding from the lower surface of the switch base 13 and the side surface engaging portion 26 formed with a recess on the side surface of the switch cover 12 are attached to an L-shaped mounting base. 27 and attach it to the equipment.

As mentioned above, there is a local contact part that protrudes slightly from the contact surface on the top surface of the terminal that connects and disconnects with the coil spring, so this contact part provides a reliable contact action and improves contact reliability. You can get a high switch.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention, with Fig. 1 being a partially cutaway plan view of a small switch, Fig. 2 being a partially longitudinal side view of the small switch, and Fig. 3 being a partially longitudinal sectional front view of the small switch. , FIG. 4 is a perspective view of the small switch, FIG. 5 is an enlarged longitudinal cross-sectional view of the main part of the contact portion, and FIG. 6 is a circuit diagram of the small switch of the double A contact type. 11...Small switch, 12...Switch cover, 13...Switch base, 14...Plunger, 15...Common terminal, 16...Other terminals, 17
...Switch mechanism, 18...Spring insertion hole,
19...Contact part, 20...Coil spring, 2
1...Movable contact part.

Claims (1)

[Claims for Utility Model Registration] A switch cover holds two plungers so as to be able to slide up and down at a predetermined interval, and a spring insertion hole is formed in the upper surface position corresponding to the plungers of a switch base that is joined to the switch cover. A conductive coil spring is interposed between the spring insertion hole and the plunger, with a large diameter coil formed in the middle part and set as a movable contact, and a common conductive coil spring is installed at the center of the upper surface of the switch base. Other terminals are insert-molded on both sides of the terminal, and the outer end of each terminal extends outward from the switch base, and the inner end of each terminal is connected to the common terminal side across the spring insertion hole. and the other terminal side are facing each other,
and a small switch, in which a fixed contact is formed by being exposed on the upper surface of the hole edge at a position corresponding to contact and separation with the large-diameter coil portion of the coil spring, and a contact portion slightly protruding from the contact surface is formed in each of the fixed contact portions. .