JP2002329436A - Cover member for push-button switch and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cover member for a push-button switch thinner than a conventional one and its manufacturing method by changing the structure and an combination method of its constitutional member in the cover member for the push-button wherein a printing sheet displayed of a function of its push- button on a surface of a key top is covered. SOLUTION: A pressurized and protruded part 3 formed at the rear face of the key top 2 is penetrated of a through hole 4 installed at an elastic sheet 1, and the tip part of the pressurized and protruded part 3 is protruded from the rear face of the elastic sheet 1, a conductive energizing member 5 in an inverted bowl state contacted with a movable junction is adhered and fixed to the tip part of the pressurized and protruded part 3, and a space 9 to enable free elastic deformation of the conductive energizing member 5 is installed at the rear face of the elastic sheet 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover member for a push-button switch used for a push-button switch of a mobile communication device such as a portable telephone, a car telephone, etc., an electronic organizer, a measuring device, a remote controller and the like. The present invention relates to a cover member for a push button switch in which a key sheet is covered with a print sheet on which the function of the push button is displayed. More specifically, despite the fact that the movable contact, which also serves as an urging member for generating a click feeling when operating the push button switch, is incorporated inside the cover member, the thickness of the entire cover member is extremely thin. And a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, this type of cover for a push button switch has been demanded to be lighter, thinner, and smaller because the body of the cover member for the push button switch is incorporated. Is required.

[0003] A cover member for a push button switch in which a printing sheet is coated on the surface of a key top is provided with the arrangement of components required for realizing the function in a stable state and the physical size thereof. Due to the limitation, there is a limit in making the thickness smaller in the conventional one.

That is, as shown in FIG. 5, in the print sheet 20, the print layer 22 of the print sheet 20 is destroyed by heat generated during the injection molding for integrating the print sheet 20 and the key top 21. In order to prevent this, a distance T2 of 1 mm or more from the gate surface 23 of the key top 21 to the printing layer 22 of the printing sheet 20 is required. Here, the total thickness T1 of the print sheet 20 and the print layer 22 is 0.05.
mm is common.

In addition, from the gate surface 23 to the elastic sheet 24, the gate remaining 25 after the gate is cut is the elastic sheet 2
In order to avoid contact with No. 4, a dimension T3 of 0.4 mm is usually required.

The elastic sheet 24 incorporated to ensure the dustproof and waterproof function has a thickness T4 at the center of the key top 21 in consideration of the productivity and the function of effectively pressing the metal disc spring 26. Of about 0.35 mm is used.

Further, the metal disc spring 26 as an urging member for generating a click feeling has an outer diameter of 4 mm.
And a height T5 of about 0.19 mm or an outer diameter of 5 mm and a height T5 of about 0.25 mm are often used.

[0008]

Therefore, in the conventional cover member 30 for a push button switch in which these components are combined, the dimension (total height) from the surface of the printing sheet 20 to the end surface of the metal disc spring 26 is set. But the printing sheet 20
+ Printing layer 22 + key top 21 (heat shielding of printing layer 22 +
Escape of gate remaining 25) + elastic sheet 24 + metal disc spring 26 = T1 + T2 + T3 + T4 + T5 = 0.05 + 1
+ 0.4 + 0.35 + (0.19-0.25) = 1.9
It was in the range of 9 to 2.05 mm, and could not be made thinner than this thickness.

The conventional elastic sheet 24 has a low rubber hardness (JIS-A 40 degrees) in order to satisfy the dustproof and waterproof function.
And, since it is an integrally molded product including the pressing protrusion 27, the pressing protrusion 27 that contacts the metal disc spring 26 and moves the metal disc spring 26 naturally has the same hardness as the elastic sheet 24. . In terms of operational sensation, the harder pressing protrusion 27 can accurately convey the mechanical click feeling of the metal disc spring 26. However, only the pressing protrusion 27 is separately designed for the reason described above. I couldn't.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a cover member for a push button switch in which a printing sheet on which the function of the push button is displayed is covered on the surface of the key top. It is an object of the present invention to provide a cover member for a push button switch which is thinner than a conventional one and a method for manufacturing the same by changing the structure and combination of the components.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a key top for a pressing operation, and a fixing provided on a switch circuit board by the pressing operation of the key top. A movable contact that can contact the contact,
In a cover member for a push button switch having an elastic sheet disposed between the movable contact and the fixed contact, a through hole in which a pressing projection formed on a back surface of the key top is provided in the elastic sheet , The tip of the pressing protrusion projects from the back surface of the elastic sheet, and an inverted bowl-shaped conductive urging member as the movable contact is bonded to the tip of the projecting pressing protrusion. It is characterized in that a space is provided on the back surface of the elastic sheet that allows the conductive urging member to freely elastically deform.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a sealing means is provided between the pressing projection and the through hole.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the sealing means forms a concave portion on an outer peripheral surface of the pressing projection and forms a convex portion fitted with the concave portion. The elastic sheet is formed on the inner surface of the through hole.

According to a fourth aspect of the present invention, in addition to the configuration of the second aspect, the sealing means includes an adhesive which adheres and fixes the pressing projection and the conductive urging member to the pressing projection. It is characterized by being filled in a gap between the portion and the through hole.

According to a fifth aspect of the present invention, there is provided a manufacturing method for a key top for a pressing operation, a movable contact capable of contacting a fixed contact provided on a switch circuit board by the pressing operation of the key top, and In a method for manufacturing a cover member for a push button switch having an elastic sheet disposed between a movable contact and the fixed contact, a through-hole provided in the elastic sheet with a pressing projection provided on a back surface of the key top A step of applying an adhesive to the tip of the pressing projection, and a step of applying an adhesive to the pressing projection in the shape of an inverted bowl-shaped conductive urging member that contacts the movable contact. The step of installing and the step of sucking the adhesive from the conductive urging member side to the key top member side allow the gap between the pressing protrusion and the through hole to be filled with the adhesive. The key It is characterized by integrating the top and the elastic sheet and the conductive biasing member.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment of the Invention] FIG. 1 is a sectional view of a main part of a cover member for a push button switch according to a first embodiment of the present invention.

In the first embodiment of the present invention, the elastic sheet 1 and the key top 2 are separate. The key top 2 is made of a transparent hard thermoplastic resin (for example, polycarbonate resin: PC) and has a pressing projection 3
Are integrally molded. On the other hand, the elastic sheet 1 is formed of an elastic silicone resin or the like, and the key top 2 is formed.
A through hole 4 through which the pressing protrusion 3 can penetrate is provided at a position where a hole is required.

The shape of the through hole 4 of the elastic sheet 1 may be a simple cylindrical shape as shown in FIG. 1, or may be a truncated cone having an inclination along the axial direction.

The shape of the pressing projection 3 may be a simple cylindrical shape as shown in FIG. 1 or a frusto-conical shape in which the substrate side is narrowed by providing an inclination along the axial direction. . An inverted bowl-shaped metal disc spring 5 as a conductive urging member for generating a mechanical click feeling is bonded and fixed to the tip of the pressing projection 3 with an adhesive 6. Adhesive 6
Is filled in a gap between the through hole 4 of the elastic sheet 1 and the pressing protrusion 3 of the key top 2.

On the back surface of the elastic sheet 1, there is provided a space 9 in which the metal disc spring 5 can be freely elastically deformed each time the key top 2 is pressed.

Further, the combination of the through hole 4 and the pressing projection 3 may be such that the inner peripheral surface of the through hole 4 and the outer peripheral surface of the pressing projection 3 are flat with each other, as shown in FIG. Alternatively, a concave portion may be formed on the outer peripheral surface of the pressing projection 3, and a convex portion fitted with the concave portion may be formed on the inner peripheral surface of the through hole 4. The cross-sectional shapes of the concave portion and the convex portion may be determined as appropriate, such as a semicircle as shown in FIG. 2A, a rectangle as shown in FIG. 2B, a triangle as shown in FIG. Just fine. This allows
Since the airtightness between the through hole 4 and the pressing projection 3 is improved, a dustproof and waterproof function can be realized.

As described above, in the cover member 13 for the push button formed by the combination of the printing sheet 20, the key top 2, the elastic sheet 1 and the metal disc spring 5, the metal disc spring 5 As shown in FIG. 1, the dimension (total height) up to the end face is T1 + T2 + T3 + T5
= 0.05 + 1 + 0.4 + (0.19-0.25) =
It is in the range of 1.64 to 1.70 mm, and can be 0.35 mm thinner than the conventional push button cover member 30. Therefore, by employing the configuration of the first embodiment, it is possible to provide a cover member for a push button switch that is thinner than a conventional one.

Hereinafter, a method of manufacturing a cover member for a push button switch according to Embodiment 1 of the present invention will be described.

FIG. 3 is a cross-sectional view of a main part of the injection molding die showing a molding state of the key top member. FIG. 4 is a cross-sectional view of a main part showing a process of integrating the key top member, the elastic sheet, and the conductive urging member.

In FIG. 3, a printing sheet 20 made of polyethylene terephthalate (PET) or polycarbonate (PC) having a printing layer 22 on which a desired design is printed in advance at a place where the key top 2 is to be placed is placed in a desired position in advance. A pin gate G which is set between the concave mold 7 and the convex mold 8 formed in a shape and is connected to the gate surface 23 at the center of the pressing projection 3 provided at the center of the key top 2. , A transparent high-temperature and high-pressure molten resin (for example, PC resin) as a material of the key top 2 is injected. Then, the printing sheet 20 is stretched and deformed by the heat and pressure of the molten resin, and closely adheres to the inner surface of the cavity C of the concave mold 7 to be formed into a desired shape. At this time, the printing sheet 20
Filled with molten resin on the inner surface of the key top 2
Is also molded. Thereafter, after cooling, the molded product is taken out from the concave mold 7 and the convex mold 8, and unnecessary portions of the print sheet 20 are removed.
Top member 12 formed integrally with key top 2
Is completed.

Next, as shown in FIG. 4, the elastic sheet 1 is directed from above with the pressing protrusion 3 of the key top 2 manufactured by injection molding facing upward.
The pressing projections 3 are inserted into the through holes 4 of the elastic sheet 1 so that the elastic sheet 1 and the key top 2 are integrated. At this time, the through hole 4 can be used as a positioning hole when the pressing projection 3 is inserted, so that assembly is facilitated.

Next, the key top 2 projecting from the through hole 4
The adhesive 6 is applied to the tip of the pressing projection 3 of FIG. On the other hand, a jig J in which metal disc springs 5 as conductive biasing members are aligned and arranged at predetermined intervals in advance with the through holes 4 of the elastic sheet 1 is brought close to the elastic sheet 1 from above, and the metal disc spring is 5
Is pressed against the tip of the pressing projection 3 to which the adhesive 6 has been applied. Then, the adhesive 6 is applied to the elastic sheet 1.
Flows into the gap between the through hole 4 and the pressing projection 3, and the elastic sheet 1 and the key top member 12 are integrated without any gap.

Then, after the adhesive 6 is cured, the jig J is removed from the key top member 12, and the elastic sheet 1, the key top member 12, and the metal disc spring 5 are integrated into a push button cover member. 13 is completed.

When the metal disc spring 5 is set on the jig J, it is fixed by magnetic force, and when the adhesive 6 is hardened, the magnetic force is released so that the metal disc spring 5 can be removed from above. The spring 5 can be supplied.

In addition, one of the contact surfaces between the key top member 12 and the elastic sheet 1 is roughened beforehand, and the metal disc spring 5 and the key top member 12 communicate with each other with the elastic sheet 1 interposed therebetween. A communication path (not shown) is formed, and the air on the side of the metal disc spring 5 is sucked from the key top member 12 side of the elastic sheet 1 through this communication path, so that the adhesive 6 May be positively guided to the key top member 12 so as to fill the gap between the through hole 4 of the elastic sheet 1 and the pressing protrusion 3 of the key top 2. This allows
Since the adhesive 6 can quickly and surely fill the gap, productivity is improved.

[0032]

As described above, according to the first aspect of the present invention, the pressing projection formed on the back surface of the key top passes through the through hole provided in the elastic sheet. The distal end of the pressing protrusion protrudes from the back surface of the elastic sheet, and an inverted bowl-shaped conductive urging member, which is a movable contact, is adhesively fixed to the distal end of the protruding pressing protrusion. Since there is provided a space that allows free elastic deformation of the conductive biasing member, a cover member for a push button switch in which the printing sheet on which the function display of the push button is displayed is covered on the surface of the key top, A cover member for a push button switch having a dust-proof and waterproof function, which is thinner than the conventional cover member, can be provided although a clear click feeling can be generated at the time of operation.

According to the second aspect of the present invention, since the sealing means is provided between the pressing projection and the through hole, in addition to the effect of the first aspect, the airtightness between the pressing projection and the through hole is provided. As a result, the dustproof and waterproof function is further improved.

According to the third aspect of the present invention, in the sealing means according to the second aspect, a concave portion is formed on the outer peripheral surface of the pressing protrusion, and the convex portion fitted with the concave portion is penetrated by the elastic sheet. Since it is formed on the inner surface of the hole, in addition to the effect of the first aspect, the airtightness between the pressing projection and the through hole can be maintained only by fitting, so that the assembly becomes easy.

According to the fourth aspect of the present invention, the sealing means according to the second aspect of the present invention provides an adhesive in which the pressing protrusion and the conductive urging member are bonded and fixed to each other. Since the space is filled, in addition to the effect of the first aspect, no means other than the adhesive is required to maintain airtightness.

According to the manufacturing method of the fifth aspect, the step of inserting the pressing projection provided on the back surface of the key top into the through hole provided in the elastic sheet and projecting the projection on the back surface of the elastic sheet. And a step of applying an adhesive to the tip of the pressing protrusion, a step of installing an inverted bowl-shaped conductive urging member that hits the movable contact on the pressing protrusion, and pressing the adhesive from the conductive urging member side The step of sucking the top member side integrates the key top, the elastic sheet, and the conductive biasing member in a state where the gap between the pressing protrusion and the through hole is filled with an adhesive, so that the surface of the key top is In the cover member for a push button switch, which is covered with a printed sheet on which the function display of the push button is made, a clear click feeling can be generated at the time of operation, but a dust-proof and waterproof function is provided. Thin push button switch Manufacturing method of use the cover member can be provided. Further, the bonding step for integrating the key top, the elastic sheet and the conductive urging member is only required once, and the filling of the adhesive is performed quickly and reliably, so that the productivity is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main part of a first embodiment of a cover member for a push button switch according to the present invention.

FIG. 2 is an enlarged view of a main part showing a combination of a pressing protrusion and a through-hole according to the first embodiment, wherein the cross-sectional shape of the protrusion of the through-hole is semicircular in FIG. b) is a rectangle,
FIG. 2C shows a triangular shape.

FIG. 3 is a cross-sectional view of a main part of the injection molding mold, illustrating a molding state of the key top member according to the first embodiment.

FIG. 4 is a fragmentary cross-sectional view showing a step of integrating the key top member, the elastic sheet, and the conductive urging member in Embodiment 1;

FIG. 5 is a sectional view of a main part of a conventional cover member for a push button switch.

[Explanation of symbols]

 1,24 elastic sheet 2,21 key top 3,27 pressing projection 4 through hole 5,26 metal disc spring (conductive biasing member) 6 adhesive 9 space 12 key top member 13,30 push button cover member 20 Print sheet 22 Print layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01H 13/14 H01H 13/14 BF Term (Reference) 5G006 AB25 AZ02 BA01 BB03 BC03 FB04 5G023 AA11 CA41 5G052 AA05 BB01 HA01 HA08 HB07 HC04

Claims (5)

[Claims] 1. A key top for a pressing operation, a movable contact capable of contacting a fixed contact provided on a switch circuit board by the pressing operation of the key top, and a movable contact between the movable contact and the fixed contact. A push button switch cover member having an elastic sheet disposed therein, wherein a pressing protrusion formed on a back surface of the key top penetrates a through hole provided in the elastic sheet, and a distal end portion of the pressing protrusion. Projecting from the back surface of the elastic sheet, an inverted bowl-shaped conductive urging member as the movable contact is adhesively fixed to the tip of the protruding pressing protrusion, and the back surface of the elastic sheet is A cover member for a push button switch, wherein a space is provided for enabling a free elastic deformation of the conductive urging member. 2. The cover member for a push button switch according to claim 1, wherein sealing means is provided between said pressing projection and said through hole. 3. The sealing means is characterized in that a concave portion is formed on the outer peripheral surface of the pressing projection, and a convex portion fitted with the concave portion is formed on the inner surface of a through hole of the elastic sheet. The cover member for a push button switch according to claim 2. 4. The sealing means is characterized in that a gap between the pressing protrusion and the through hole is filled with an adhesive which fixes and fixes the pressing protrusion and the conductive urging member. The cover member for a push button switch according to claim 2. 5. A key top for a pressing operation, a movable contact capable of contacting a fixed contact provided on a switch circuit board by the pressing operation of the key top, and a movable contact between the movable contact and the fixed contact. In the method for manufacturing a cover member for a push button switch having an elastic sheet to be disposed, a pressing projection provided on a back surface of the key top is inserted into a through hole provided in the elastic sheet, and is inserted into a back surface of the elastic sheet. Projecting, applying an adhesive to the tip of the pressing protrusion, installing an inverted bowl-shaped conductive urging member that hits the movable contact on the pressing protrusion, and applying the adhesive to the pressing protrusion. The step of sucking from the conductive urging member side to the key top member side allows the key top, the elastic sheet, and the conductive sheet to be in a state in which a gap between the pressing protrusion and the through hole is filled with the adhesive. A method for manufacturing a cover member for a push button switch, wherein the cover member is integrated with a sex biasing member.