JPH0528875A - Push button switch and its manufacture - Google Patents

Abstract

PURPOSE:To assemble a waterproof push button switch in a simple assembly process and using a lesser number of parts. CONSTITUTION:A stem 20 consists of a body 34 and a ring-form mounting part 38 to be formed thereon rigidly through a thin deflective part 36, and is formed from elastic plastics through injection molding. A holder 16 consists of an inner holder part 30 formed previously from elastic plastics and having stationary contacts 12, 12', 14 and an outer holder part 32 embodied through injection molding etc. so as to enwrap the inner holder part 30. The stem 20 is installed by heat fusion attachment, when the outer holder part 32 is injection molded, so that the ring-form mounting part 38 is pinched by the inner holder part 30 and outer holder part 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof pushbutton switch having an airtight structure and an improvement in its manufacturing method.

[0002]

2. Description of the Related Art Generally, push button switches of this type are
An insulating holder having a plurality of fixed contacts on the bottom of the inner surface,
It consists of a dome-shaped leaf spring movable contact that is arranged in the holder so as to be opposed to these fixed contacts, and a stem that is attached to the holder and presses the movable contact against the fixed contacts.

The push-button switch of the prior art is provided with a flexible sealing sheet member having an inner stem portion engaged with a movable contact for waterproofing, and a watertight seal on the flexible sealing sheet member. With a metal cover attached to keep it,
The metal cover includes an outer stem portion that can be lifted and lowered, and the flexible sealing sheet is attached to the holder via an adhesive sheet having elasticity, and the metal cover uses the flexible sealing sheet of the holder. The fixing pin is swaged so as to be pressed against the engaging surface.

[0004]

However, this prior art push button switch requires a flexible sealing sheet member separately from the metal cover for attaching the stem in order to impart waterproofness. Since the internal and external stems are required, the number of parts is increased, and a special adhesive sheet is required to attach the flexible sealing sheet member to the holder while keeping it watertight, which makes the assembly complicated and expensive. There was a drawback.

An object of the present invention is to provide a push button switch which has a small number of parts, is easy to assemble, and is waterproof.

Another object of the present invention is to provide a method of manufacturing a pushbutton switch which can easily manufacture a waterproof pushbutton switch with a small number of parts in a simple process.

[0007]

One of the means for solving the problems of the present invention is to provide an insulating holder having a plurality of fixed contacts at the bottom of the inner surface thereof, and an inside of the holder so as to be arranged so as to face these fixed contacts. In a push button switch consisting of a leaf spring movable contact arranged and a stem attached to the holder for pressing the movable contact against the fixed contact, the holder covers the plastic inner holder portion having the fixed contact and the inner holder portion. And a plastic outer holder portion provided, and the stem comprises a plastic stem body and an elastic plastic annular mounting portion integrally formed around the stem body through a thin-walled bending portion,
The annular mounting portion is to provide a push button switch characterized by being fused and mounted to the outer holder portion between the inner holder portion and the outer holder portion.

Another object of the present invention is to provide an insulative holder having a plurality of fixed contacts on the bottom of the inner surface thereof, and a dome-shaped movable member arranged in the holder so as to face the fixed contacts. In a method of manufacturing a pushbutton switch including a contact and a stem that is attached to a holder and presses a movable contact against a fixed contact, a plastic inner holder part having a fixed contact for a holder is formed in advance, and a stem is made of a plastic. It is formed by a stem body and an elastic plastic annular mounting portion that is integrally formed around the stem body via a thin-walled bending portion, and the annular mounting portion is formed by an inner holder so that the stem body of the stem engages with the movable contact. The outer holder part by injection molding so as to wrap the inner holder part and the annular mounting part of the stem after placing it on the inner part. It is to provide a method of manufacturing a push-button switch according to claim.

Still another object of the present invention is to provide a method for manufacturing the above push button switch, wherein the stem has a positioning protrusion that engages with the inner peripheral surface of the inner holder part.
Provided is a method for manufacturing a pushbutton switch, characterized in that, when the stem is placed on the inner holder part, its positioning protrusion is engaged with the inner peripheral surface of the inner holder part to set the stem at the correct position of the inner holder part. To do.

[0010]

As described above, the holder is formed of the preformed inner holder portion and the outer holder portion provided by injection molding or the like so as to wrap the inner holder portion, and the stem is formed on the stem body and the thin-body bending portion on the stem body. When the stem is attached to the outer holder part by fusion or the like so as to sandwich the annular mount part between the inner holder part and the outer holder part, the stem and its mounting member are formed. Since the number of parts is extremely small and the stem is attached to the outer holder while keeping its watertightness, the stem can be easily assembled in a simple process.

[0011]

1 and 2 show a pushbutton switch 10 assembled according to the method of the present invention, the pushbutton switch 10 having a bottom inner surface. A plurality of fixed contacts 12, 12 'and 1
Insulating holder 16 having 4 and these fixed contacts 1
Holder 1 so that it is arranged facing 2, 12 ', 14
A dome-shaped leaf spring movable contact 18 arranged in
The movable contact 18 is attached to the holder 16 and the movable contact 18 is fixed contact 12,
It consists of a stem 20 that presses across 12 'and 14.

In the illustrated embodiment, as shown in FIGS. 2 and 3, the fixed contacts 12 and 12 'are arranged on both sides of the fixed contact 14, and the fixed contacts 12 and 12' are connected to the connecting pieces 22 and 2.
2'is connected to the conductor piece 24A serving as the lead terminal 24, and the fixed contact 14 is connected to the conductor piece 28A serving as the lead terminal 28 via the connecting piece 26.

As shown in FIG. 2, the dome-shaped movable contact 18 is arranged so that its peripheral edge engages with the fixed contacts 12 and 12 ′, and is pushed by the stem 20 to be bent so that the center thereof is bent so that the fixed contact 14 is fixed. Fixed contact 1
Electrically connects 2, 12 'and 14.

The holder 16 includes fixed contacts 12, 12 ', 1
4 and a plastic outer holder portion 32 provided so as to cover the inner holder portion 30. The inner holder portion 30 is formed by injection molding from polybutylene terephthalate (PBT) so that the fixed contacts 12, 12 ′ and 14 and the lead terminals 24 and 28 continuous with the fixed contacts 12 and 12 are inserted. The outer holder part 32 sandwiches the inner holder part 30 and the dome-shaped movable contact 18, and the inner holder part 3
0 is provided by injection molding so as to enclose the annular mounting portion of the stem 20 arranged on the upper part of the No. 0, and the annular mounting portion of the stem 20 is fused, but the details will be described later.

As shown in detail in FIGS. 2 and 3, the stem 20 includes a plastic stem main body 34 and a plastic annular mounting integrally formed around the stem main body 34 with a thin-wall flexure 36. It consists of a part 38. The stem 20 is formed by injection molding from an elastic plastic generally called a polyester elastomer in which a rubber component is mixed with PBT which is the same material as the inner holder portion 30. As can be seen from FIG. 2, an annular positioning projection 40 is integrally provided on the inner surface of the annular mounting portion 38, and this projection 40 is provided with the stem 2 as described later.
It has a function of setting 0 to the correct position with respect to the inner holder portion 30 of the holder 16.

Next, a method of manufacturing the push button switch 10 of the present invention will be described in detail. First, as shown in FIG. 4, a pair of conductor pieces 24A, 28A formed by punching out a metal strip such as copper and the conductor pieces 24A, 28A are integrally connected to each other via connecting pieces 22, 22'26. A plurality of sets of fixed contacts 12, 12 'which are connected and are formed at intervals in the longitudinal direction.
A terminal material 42 including and 14 is prepared. Next, as shown in FIG. 5, this terminal material 42 is inserted and the inner holder portion 30 is injection-molded as previously described.
As can be seen from FIG. 5, a plurality of inner holder portions 30 are simultaneously formed by injection molding for each portion having a set of fixed contacts. Further, as can be seen from FIG. 5, the inner holder portion 30 is composed of a substantially square base portion 30A and a shallow cylindrical portion 30B formed on the base portion 30A, and a vertical portion facing the inner surface of the cylindrical portion 30A. Grooves 44, 44 'are formed. These vertical grooves 44, 44 ′ are provided so that the fixed contacts 12, 12 ′ on both sides, which have been previously filled, escape from the burrs formed on the inner peripheral surface of the inner holder portion 30 when the inner holder portion 30 is molded.

On the other hand, as shown in FIGS. 2 and 5, the dome-shaped leaf spring movable contact 18, which is separately formed in advance, is arranged so as to engage with the fixed contacts 12 and 12 'of the inner holder portion 30, and The annular mounting portion 3 of the stem 20 that is separately formed in advance so that the stem body 34 engages with the movable contact 18.
8 is placed on the shallow cylindrical portion 30B of the inner holder portion 30. In this case, since the positioning protrusion 40 of the stem 20 is engaged with the inner peripheral surface of the inner holder portion 30 as shown in FIG. 3, the stem 20 is automatically set to the correct position with respect to the inner holder portion 30. .

After mounting the stem 20 on the inner holder portion 30 in this manner, as shown in FIGS. 2 and 3,
The outer holder portion 32 is injection-molded so as to wrap the inner holder portion 30 and the annular mounting portion 38 of the stem 20. The outer holder portion 32 includes the inner holder portion 30 and the stem 2.
It is made of a material such that the No. 0 annular mounting portion 38 is fused, for example, the same PBT as the inner holder portion 30.

As already mentioned, since the annular mounting portion 38 of the stem 20 is made of the elastic plastic in which PBT is mixed with the rubber component, the outer holder is wrapped around the inner holder portion 30 and the annular mounting portion 38 of the stem 20. Part 3
When 2 is injection-molded, the elastic annular mounting portion 38 of the stem 20 adheres to the inner holder portion 30 while maintaining watertightness, and is also fused to the outer holder portion 32 at the contact surface 46 indicated by the thick line in FIGS. 2 and 3. Therefore, the pushbutton switch 10 having a sealed structure having a waterproof property is formed.

A plurality of push button switches 10 which are continuous with the terminal material 42 are shown in FIGS. 1 to 3 in which the portions protruding from the outer surface of the holder 16 are formed by cutting and molding at the intermediate portions of the conductor pieces 24A and 28A. As described above, it is bent downward and divided into a single push-button switch 10 having water proof property and completed.

[0021]

According to the present invention, as described above, since the stem is formed by the stem body and the annular mounting portion integrally formed with the stem body through the thin-walled bending portion, the stem and its mounting member. And the number of parts is significantly reduced, and the holder is formed by a preformed inner holder part and an outer holder part provided by injection molding or the like so as to wrap the inner holder part, and the stem annular mounting part is formed by the inner holder part. Since it is attached to the outer holder part by heat fusion so as to be sandwiched between the outer holder part and the outer holder part, the stem's annular mounting part can be attached to the outer holder part in a watertight manner so that a waterproof push button switch can be easily manufactured. There is a real benefit that can be easily assembled with.

[Brief description of drawings]

FIG. 1 is a perspective view of a push button switch manufactured by a manufacturing method of the present invention.

FIG. 2 is a cross-sectional view of a push button switch manufactured by a manufacturing method of the present invention in a direction in which fixed contacts are lined up.

FIG. 3 is a cross-sectional view in a direction perpendicular to a direction in which fixed contacts of a push button switch manufactured by the manufacturing method of the present invention are arranged.

FIG. 4 is a perspective view of a part of the terminal material used in the manufacturing method of the present invention.

FIG. 5 is a perspective view showing an exploded process in the middle of the manufacturing method of the present invention.

[Explanation of symbols]

10 push button switch 12 fixed contacts 12 'fixed contact 14 fixed contacts 16 holder 18 Dome-shaped leaf spring movable contact 20 stems 22 Connecting piece 22 'connecting piece 24 lead terminals 24A conductor piece 26 Connecting piece 28 lead terminals 30 Inner holder part 32 Outer holder part 34 Stem body 36 Thin wall flexure 38 Annular mounting part 40 Positioning protrusion 42 terminal material 44 vertical groove 44 'flute 46 Contact surface

Claims (3)

[Claims] 1. An insulative holder having a plurality of fixed contacts on the bottom of the inner surface thereof, a leaf spring movable contact arranged in the holder so as to be opposed to the fixed contacts, and attached to the holder. In the push button switch including a stem that presses the movable contact against the fixed contact, the holder includes a plastic inner holder part having the fixed contact and a plastic outer holder part provided so as to cover the inner holder part. The stem comprises a plastic stem main body and an elastic plastic annular mounting portion integrally formed around the stem main body via a thin flexible portion, and the annular mounting portion includes the inner holder portion and the outer holder portion. A push-button switch, characterized in that the push-button switch is fused and attached to the outer holder portion between. 2. An insulative holder having a plurality of fixed contacts on the bottom of the inner surface thereof, a leaf spring movable contact arranged in the holder so as to be opposed to the fixed contacts, and attached to the holder. In the method of manufacturing a push button switch including a stem that presses the movable contact against the fixed contact, a plastic inner holder part having the fixed contact for the holder is formed in advance, and the stem is made of plastic. A stem body and an annular mounting portion made of elastic plastic integrally formed around the stem body via a thin-walled bending portion, and the ring mounting so that the stem body of the stem engages with the movable contact. Part is placed on the inner holder part, and then the outer holder part is injection-molded so as to wrap the inner holder part and the annular mounting part of the stem. A method of manufacturing a pushbutton switch, characterized in that the holder is formed in a shape. 3. The stem has a positioning protrusion that engages with an inner peripheral surface of the inner holder portion, and the positioning protrusion engages with an inner peripheral surface of the inner holder portion when the stem is placed on the inner holder portion. 3. The method for manufacturing a push button switch according to claim 2, wherein the stem is inserted and the stem is set at a correct position of the inner holder portion.