JP2728145B2 - Push button switch - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a vertical push button switch having a switch body attached to a mounting plate, and in particular, to an ultra-small push button mounted by soldering to a printed circuit board. Regarding switches.

2. Description of the Related Art Generally, a push button switch of this type includes a switch body (a so-called tact switch) having a stem protruding from a front surface of a resin housing so as to be able to advance and retreat, and a switch boss of the housing being swaged. And a mounting plate made of a metal plate for holding and fixing the mounting plate, and legs are respectively provided from side plates of the mounting plate facing both sides of the housing. The push button switch is fixed on the printed circuit board and can be operated by being inserted into the mounting hole and soldered. In addition, a plurality of terminals protrude from the bottom of the housing, and these terminals are inserted into through holes in the printed circuit board and soldered, so that the contact points in the housing and the circuit pattern of the printed circuit board are conducted. It has become to be.

The step of soldering the terminals of the switch body and the legs of the mounting plate from the back side of the printed circuit board usually employs an automatic dipping method, but the structure in which the bottom surface of the housing is directly mounted on the printed circuit board is adopted. In the case of the conventional product, the flux easily penetrates into the gap between the housing and the mounting plate during this soldering process, and when this flux reaches the periphery of the stem, it causes poor conduction between the contacts and malfunction of the stem, Improvement was desired.

Therefore, the present applicant has previously proposed a push button switch described in Japanese Utility Model Laid-Open No. 58-165817. This is such that the bottom surface of the housing fixed to the mounting plate is separated from the printed circuit board and is supported on the printed circuit board by a pair of legs of the mounting plate. It is intended to prevent flux from entering the gap between the mounting plate and the mounting plate.

[Problems to be Solved by the Invention] By the way, the integration of the switch body and the mounting plate in this kind of push button switch is performed by caulking the caulking boss protruding from the housing as described above. If the size of the switch body is promoted and the swaging area cannot be increased, the necessary swaging strength may not be secured.In particular, the housing may be easily separated from the mounting plate around the stem where the pushing operation is repeated. It is feared that the switch itself will fall off and cause a serious accident.

Accordingly, it is an object of the present invention to provide a push button switch in which the switch main body is not likely to fall off from the mounting plate even if it is miniaturized.

[Means for Solving the Problems] An object of the present invention is to provide a switch body having a stem protruding from a front surface of a housing provided with a caulking boss and terminals protruding from a bottom surface of the housing; The switch body is held and fixed by caulking a caulking boss, and a mounting plate is provided that has legs protruding from side plates facing both sides of the housing, and the terminal and the legs are mounted on a printed circuit board. In a vertical push button switch which is mounted by soldering, a caulking boss of the housing is formed so as to be deviated to the stem side, and a convex portion is protrudingly provided on a side surface of the housing, and the convex portion is formed as described above. This is achieved by engaging with a window hole formed in the side plate of the mounting plate.

[Operation] According to the above-described means, the caulking strength of the front surface of the housing and the mounting plate can be increased by caulking the caulking boss which is biased to the stem side to form the caulking portion, and furthermore, the side surface of the housing. Because the convex part of the housing is locked in the window hole of the mounting plate to perform the connection function, even if the caulking area on the front of the housing can not be large due to miniaturization,
It is possible to reliably prevent the switch body from falling off from the mounting plate.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a side view showing a state in which the push button switch according to the present embodiment is mounted on a printed circuit board, FIG. 2 is a front view of the push button switch, and FIG. 3 is a plan view of the push button switch.

The push button switch shown in these figures is a very small vertical push button switch composed of a switch body 1 also called a tact switch and a metal plate mounting plate 2 holding and fixing the switch body 1. Used by mounting on a substrate.

A stem 4 protrudes from the front surface 3a of the housing 3 of the switch main body 1 so as to advance and retreat, and two terminals 5 protrude from a bottom surface 3c of the housing 3. A caulking boss 6a (third) protruding from two places on the front surface 3a of the housing 3
(See the figure) is formed in advance by biasing the thickness toward the stem 4 side. These caulking bosses 6a are inserted into the caulking holes of the front plate 2a of the mounting plate 2 and caulked to form the caulking portion 6. Thereby, the housing 3 is fixed to the mounting plate 2 in a state where the front surface 3a and both side surfaces 3b, 3b are surrounded. Projections 7 project from both sides 3b of the housing 3, and each projection 7 is inserted into the window 8 of the side plate 2b of the mounting plate 2, and It is in contact with the rim.

On the other hand, the mounting plate 2 has a short leg piece 9 projecting from the center of the bottom of the front plate 2a facing the front surface 3a of the housing 3, and the side plates facing both side surfaces 3b, 3b of the housing 3. Part 2
A long leg bent from b and 2b into a substantially rectangular shape
There are 10 protruding. As described above, each side plate portion 2b is provided with a window hole 8 for inserting the convex portion 7 of the housing 3 and a notch 11 for ensuring a creepage distance with the terminal 5 is provided at the bottom. It is provided.

When mounting such a push button switch on the printed circuit board 12, the terminal 5 is inserted through the through hole 13 and the leg 10 is inserted into the mounting hole 14, as shown in FIG. The soldering is performed from the back surface side of the printed circuit board 12 by an automatic dipping method in a state where the positioning and the contact terminal 10a of the leg 10 are brought into contact with the printed circuit board 12 and positioned. The push-button switch, which has been soldered in this manner, is connected to the circuit pattern of the printed circuit board 12 through the terminals 5 through the contacts 5 in the housing 3 and to the printed circuit board 12 through the legs 10.
However, the switch body 1 is held and fixed in a state of being separated from the printed circuit board 12. That is, the push button switch is attached to the leg 9 of the mounting plate 2.
And the contact end 10a of each leg 10 is supported on the printed circuit board 12 at three points.
At a predetermined height.

In the above embodiment, even if the flux during the soldering step enters through the gap between the through hole 13 and the mounting hole 14,
Since the bottom surface 3c of the housing 3 is separated from the printed circuit board 12, the flow of the flux is weakened, and the flux passing through the terminal 5 is hardly transmitted to the side plate 2b of the mounting plate 2 due to the presence of the notch 11. Furthermore, since the flux passing through the leg 10 is hardly transmitted to the front plate 2a of the mounting plate 2, there is almost no possibility that the flux reaches the periphery of the stem 4 in the end. Insufficient conduction and poor operation of the stem 4 are avoided. Moreover, the notch 11 allows the side plate 2b of the mounting plate 2 and the terminal 5
Therefore, there is less danger that the mounting plate 2 bearing the static electricity will cause a discharge between the terminal 5 and the mounting plate 2.

Further, in the above embodiment, since the push button switch is configured to be supported at three points on the printed circuit board 12,
If the mounting plate 2 for holding the switch main body 1 is formed slightly larger than the switch main body 1, the push button switch on the printed circuit board 12 can be stably self-supported. Therefore, the pushbutton switch can be reduced in size and thickness, and the mounting density can be improved.

Further, in the above embodiment, a pair of caulking bosses located on both sides of the stem 4 on the front surface 3a of the housing 3 are provided.
Each of the swaging bosses 6a is swaged even if the swaging area cannot be sufficiently increased due to the downsizing of the switch body 1 because the thickness of the swaging body 6a is formed so as to be uneven toward the stem 4. 6, the front of the housing 3
Reference numeral 3a is adapted to be securely fixed to the mounting plate 2 around the stem 4. That is, the front surface 3a of the housing 3
If the caulking strength is insufficient, it is easy to peel off from the mounting plate 2 around the stem 4. Therefore, by caulking the caulking boss 6 a with the thickness increased toward the stem 4, Unnecessary caulking strength is ensured. Furthermore, the housing 3 has the projections 7 on both sides 3b, 3b abutting against the rear edge of the window hole 8 of the mounting plate 2, and when a pressing force is applied during operation, the projections 7 8, the connection function is performed, so that the load of the caulked portion 6 on the front surface 3 a of the housing 3 is reduced accordingly. Therefore, even if the miniaturization is promoted and the swaging strength is weakened, there is no possibility that the housing 3 will fall off the mounting plate 2.

[Effects of the Invention] As described above, according to the present invention, the caulking strength of the front surface of the housing and the mounting plate is increased by caulking the caulking boss with the thickness deviated to the stem side to form a caulking portion. In addition, since the convex portion on the side of the housing is locked in the window hole of the mounting plate to perform the connection function, even if the swaging area on the front of the housing can not be large due to the miniaturization of the push button switch, It is possible to reliably prevent the switch body from falling off from the mounting plate.

[Brief description of the drawings]

1 to 3 relate to an embodiment of the present invention. FIG. 1 is a side view showing a state in which a push button switch is mounted on a printed circuit board. FIG. 2 is a front view of the push button switch. FIG. 4 is a plan view of the push button switch. 1 switch body, 2 mounting plate, 2a front plate, 2b
... side plate, 3 ... housing, 3a ... front, 3b ... side, 3c ... bottom, 4 ... stem, 5 ... terminal, 6 ... crimping section, 6a ... crimping boss, 7 ... … Projecting part, 8… Window hole, 10… Leg part, 12… Printed circuit board.

Claims (1)

(57) [Claims] 1. A switch body having a stem protruding from a front surface of a housing provided with a caulking boss and terminals protruding from a bottom surface of the housing, and the switch body being caulked by a caulking boss of the housing. Retention·
A vertical push button switch fixed and provided with a mounting plate having legs protruded from side plates facing both sides of the housing and soldering the terminals and the legs to a printed circuit board. While the caulking boss of the housing is formed so as to be deviated to the stem side,
A push button switch, wherein a protrusion is provided on a side surface of the housing, and the protrusion is engaged with a window formed in a side plate of the mounting plate.