JPH0539538Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to switches used in various input devices such as personal computers and word processors, and in particular, the invention relates to switches used in various input devices such as personal computers and word processors. This invention relates to a type of switch whose terminals are soldered to solder lands on a printed circuit board.

[Conventional technology]

Figures 2 to 5 show an example of a conventional push button switch. Figure 2 is a sectional view of the push button switch, Figure 3 is a bottom view of the push button switch with the lower case removed and the upper case visually observed, and Figure 3 is a bottom view of the push button switch with the lower case removed and the upper case visually observed. FIG. 4 is an exploded perspective view of a switch element provided in the push button switch, and FIG. 5 is an explanatory diagram showing the state in which the push button switch is mounted on a printed circuit board.

In FIGS. 2 and 3, 1 is a lower case and 2 is an upper case, and these upper and lower cases 1 and 2 are integrated by a snap engagement (not shown). An insertion hole 2a is formed at the center of the upper surface of the upper case 2, and a stem 3 forming a part of the operating member is inserted through the insertion hole 2a. A spring 5 is interposed between the stem 3 and the inner bottom surface of the lower case 1, and a key top 4 as an operating member is fitted and fixed to the upper part of the stem 3.

A switch element 6 is disposed on one side of the case formed by the lower case 1 and the upper case 2, and as shown in FIG.
is supported by the upper case 2 by the protrusion 2b so as not to move toward the stem 3 side. The configuration of this switch element 6 will be described later, but the switch element 6
A pressure spring 11 is hooked to the upper part of the holder. The pressure spring 11 has a bent portion 11a, an extended portion 11b, and an operating projection 11c.The extended portion 11b extends below the stem 3 and has a forked tip. The portion is adapted to enter the reciprocating range of the stem 3.

On the other hand, a leaf spring 12 is disposed on the opposite side of the switch element 6 with the stem 3 interposed therebetween. This leaf spring 12 has an upright part 12a extending along the inner surface of the side wall of the upper case 2 and an extending part 12b extending toward the lower part of the stem 3, and the lower part of the extending part 12b abuts the lower part of the stem 3. This abutting portion serves as a click protrusion 12c that moves back and forth in the reciprocating range of the stem 3 during its reciprocating motion. Further, the upright portion 12a is held between the side wall of the upper case 2 and the base pressing plate 13.
is supported by the upper case 2 by the protrusion 2c so as not to move toward the stem 3 side.

As shown in FIG. 4, the switch element 6 is
An operating body 7 made of synthetic resin and a movable contact 8 made of metal
, a spacer 9 made of synthetic resin, and a fixed contact 10 made of metal, and the operating body 7 has a pressing piece 7a.
The movable contact 8 consists of a frame 8a and a thin metal plate 8b supported by the frame 8a, a circular opening 9a is formed in the spacer 9, and the fixed contact 10 has a circular opening 9a formed therein. A fixed contact 10a is formed facing the thin metal plate 8b. Engagement holes 8c, 9b, and 10b are formed coaxially in the circumferences of the movable contact 8, spacer 9, and fixed contact 10, respectively.
Each component of the switch element 6,
That is, the actuating body 7, the movable contact 8, the spacer 9, and the fixed contact 10 are integrated in a stacked state.
In addition, 8d is a movable side terminal which constitutes a part of the movable contactor 8, and 10c is a fixed side terminal which constitutes a part of the fixed contactor 10.

Next, the operation of the push button switch configured in this way will be explained.

When the key top 4 is not pressed as shown in FIG.
The stem 3 receives the urging force in the return direction of the spring 5 and the urging forces in the return direction of the pressing spring 11 and the leaf spring 12, and is positioned upward. In this case, the working protrusion 11c of the pressing spring 11 is connected to the pressing piece 7 of the actuating body 7.
A is not pressed and the thin metal plate 8b is separated from the fixed contact 10a, so the switch is in an off state.

When the key top 4 is pressed from this state, the stem 3 descends against the spring 5.
Since the click protrusion 12c retreats from the reciprocating range of the stem 3 during the forward movement, a click sensation is obtained. In addition, since the pressing spring 11 also retreats from the reciprocating motion range of the stem 3 due to the forward movement of the stem 3, the pressing piece 7a is pressed by the working protrusion 11c, and the thin metal plate 8b is brought into contact with the fixed contact 10a. It is displaced and enters the switch-on state.

When the pressing force on the key top 4 is released, the stem 3 returns to the raised position shown in FIG.
Since the pressing force on the pressing piece 7a is also released,
The thin metal plate 8b separates from the fixed contact 10a and returns to the switch-off state.

[Problem that the invention attempts to solve]

By the way, in the push button switch configured as described above, as shown in FIG. However, during this soldering, the solder land 14a and both terminals 8d, 1
Flux is applied to 0c to improve solder adhesion. However, since this flux has good wettability to metal surfaces, both terminals 8
After entering the inside of the lower case through the surfaces of d and 10c, the switch element having a laminated structure, that is, the frame 8a, comes into contact with the inner bottom surface of the lower case 1.
Alternatively, it is likely to travel along the surface of the fixed contact 10 and adhere to the thin metal plate (movable contact) 8b or the fixed contact 10a. Furthermore, since flux is an insulating substance, there is a problem in that if it adheres to the contact portions, it will cause poor contact.

In addition, in order to prevent flux from entering the contact portion, lower case 1 and each terminal 8d, 1
A push button switch in which an adhesive is applied to the gap between the push button and the 0c has also been proposed, but in this case, a new problem arises in that the process of applying the adhesive increases, resulting in higher costs.

The present invention was devised to solve the above-mentioned problems of the prior art, and its purpose is to prevent flux from entering the contact portion with a simple configuration.
The purpose is to provide an inexpensive switch with high contact reliability.

[Means for Solving the Problems] In order to achieve the above object, the present invention has a structure in which a fixed contact plate having a fixed side terminal and a movable contact plate having a movable side terminal are laminated with a film-like spacer interposed therebetween. In a switch including an integrated switch element, the fixed side terminal and the movable side terminal extend outside from the case body and are soldered to a solder land of a printed circuit board. A projection is provided between the switch element and the case body to separate the two, and the projection forms a space in which the fixed side terminal and the movable side terminal are exposed between the switch element and the case body. It is something to do.

[Effect]

As mentioned above, if a protrusion is interposed between the switch element and the main case, when the terminal is soldered to the solder land part by auto dip, the flux will pass along the surface of the terminal and enter the case main body. Flux does not invade the switch element which is spaced apart from the inner bottom surface of the main body, and no flux adheres to the contact portion. Here, since the protrusion may be integrally formed with the switch element or the lower case, penetration of flux can be prevented without using an adhesive as in the conventional case, and costs can be reduced.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is an explanatory view showing a state in which a push button switch according to an embodiment of the present invention is mounted on a printed circuit board, and members corresponding to those in FIGS. 2 to 5 are given the same reference numerals.

As shown in FIG. 1, a projection 15 is provided at the center of the lower surface of the actuating body 7, which forms a part of the switch element 6. A gap shown by A in the figure is formed. It should be noted that the push button switch according to the present embodiment has the same structure as the conventional example shown in FIGS. 2 to 5 except for the above points, and thus the explanation thereof will be omitted here.

When mounting the push button switch configured in this manner on the printed circuit board 14, after inserting both terminals 8d and 10c protruding from the bottom surface of the lower case 1 into the mounting holes of the printed circuit board 14, the printed circuit board 14 is soldered. It is immersed in a tank and both terminals 8d and 10c are soldered to the solder land portion 14a as shown in FIG. During this soldering, flux is applied to the solder land portion 14a and both terminals 8d and 10c, and a portion of the flux travels along the surfaces of both terminals 8d and 10c and rises to the vicinity of the inner bottom surface of the lower case 1. Since the switch element 6 is floating by the gap A with respect to the inner bottom surface of the lower case 1, flux will not reach the inside of the switch element 6 due to capillary action, and there will be no contact failure at the contact portion.

In the above embodiment, a case has been described in which the protrusion 15 is integrally formed on the operating body 7 on the switch element 6 side, but the same effect can be obtained even if the protrusion 15 is provided on the inner bottom side of the lower case 1.

In the above embodiment, the projection 15 is arranged in the center using the space between the terminals 8d, 10c. Protrusions may be provided between the lower case 1 and the switch element 6, respectively, and it is sufficient that the protrusions 15 form a gap between the lower case 1 and the switch element 6 to an extent that no capillary phenomenon occurs.

[Effect of idea]

As explained above, according to the present invention, the simple structure of providing a protrusion separating the switch element and the case body can prevent flux from entering the switch element, making it possible to reduce the cost. This allows us to provide switches with fewer contact failures.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a state in which a push button switch according to an embodiment of the present invention is mounted on a printed circuit board, and FIGS. 2 to 5 are explanatory diagrams of a conventional push button switch. Cross-sectional view, 3rd
The figure is a bottom view of the push button switch with the lower case removed and the upper case visible, FIG. 4 is an exploded perspective view of the switch element, and FIG. 5 is an explanatory diagram showing the state in which the push button switch is mounted on a printed circuit board. 1... Lower case (case body), 2... Upper case, 6... Switch element, 7... Operating body, 8...
Movable contactor (movable contact plate), 8b...metal thin plate,
8d...Movable side terminal, 9...Spacer, 10...
Fixed contact (fixed contact plate), 10a... fixed contact,
10c... fixed side terminal, 14... printed circuit board,
14a...Solder land part, 15...Protrusion, A...
gap.

Claims (1)

[Claims for Utility Model Registration] (1) A switch element is provided in which a fixed contact plate having fixed side terminals and a movable contact plate having movable side terminals are laminated and integrated via a film-like spacer, In a switch in which a side terminal and a movable side terminal extend outside from the case body and are soldered to a solder land on a printed circuit board, a protrusion separating the switch element and the case body; 1. A switch, characterized in that a space is formed between the switch element and the case body through which the fixed side terminal and the movable side terminal are exposed by the protrusion. (2) The switch according to claim (1), wherein the protrusion is located at the center of the fixed terminal and the movable terminal.