JPH0650916Y2 - Keyboard switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a keyboard switch used in a keyboard device such as a computer, typewriter, and word processor, and in particular, opening and closing a membrane switch by vertically moving a key stem. The present invention relates to an improvement of the key switch having the structure.

[Prior Art] FIG. 6 is a sectional view of a keyboard switch proposed by the present applicant in Japanese Patent Application No. 63-46829. As shown in the figure, a membrane switch 3 is fixed to a lower end surface of the opened frame 1 by a contact plate 2. A sliding portion 4 is provided on the frame 1 so as to be vertically movable, and is configured to press the contact portion 5 of the membrane switch 3. The sliding portion 4 has a columnar key stem 7 as a main body, which is guided through the guide hole 6 of the frame 1 and is guided in the vertical direction. A key top 8 is attached to the upper end of the key stem 7, and a base member 9 is provided to the lower end of the key stem 7. A pressing portion 10 for pressing the membrane switch 3 is horizontally provided on the base member 9 so as to surround the key stem 7, and a pressing protrusion is formed on the lower surface of the tip thereof. Further, the base member 9 is provided with a leaf spring portion 11 obliquely downward so as to push back the entire pushed-down sliding portion 4 upward. Further, a protrusion for preventing a push-cut noise is disposed below the central portion of the leaf spring portion.

[Problems to be Solved by the Invention] The conventional keyboard switch has the following problems.

(1) Since the pressing portion 10 is provided horizontally on the base member 9, it cannot reach the membrane switch unless the height of the pressing protrusion at the tip (that is, the dimension of the sliding portion in the moving direction) is large. Therefore, when the switch is pressed, the pressing protrusion slides with respect to the membrane switch due to the elastic deformation of the entire pressing portion from the position where the pressing protrusion first contacts the membrane switch to the position where the switch is completely pressed. It will be. In this case, there is a problem in that the larger the height of the pressing protrusion, the longer the sliding distance of the membrane switch, and the shorter the life of the sheet of the membrane switch.

(2) Since the pressing portion 10 is horizontal with respect to the base member 9, there is a problem that the amount of deformation (warpage) of the pressing portion 10 during operation is large and the life is shortened.

(3) Since the leaf spring portion is provided so as to be vertically inclined with respect to the base member, and the intermediate lower surface of the inclined leaf spring portion is provided with a projection for preventing push-cutting noise, it is accompanied by a pressing operation. After the protrusion comes into contact with the membrane switch, the protrusion serves as a fulcrum, and only the portion ahead of this acts as a leaf spring. That is, the leaf spring portion is not used effectively, the restoring force is weak, and the life is short.

(4) If the leaf spring portion is composed of only the inclined portion, the tip portion that is always in contact with the membrane switch is plastically deformed and warped upward with long-term use, and the portion in front of the tip portion However, there is a problem in that the full length of the leaf spring cannot be used effectively because it comes into contact with the membrane sheet.

(5) Conventionally, there is generally no protrusion at the tip of the leaf spring portion,
Even if it is provided, since it is a large semi-cylindrical projection, friction with the membrane switch occurs and the life of the membrane sheet is shortened.

The present invention has been made in view of the above problems, and an object thereof is to provide a keyboard switch having a long life, particularly a keyboard switch having a long life of a leaf spring portion and a pressing portion.

[Means for Solving the Problems] The keyboard switch according to claim 1 is a keyboard in which a membrane switch arranged on a backing plate and a sliding portion for pressing the membrane switch are arranged in a frame. In the switch, the sliding portion has a columnar key stem guided by the frame, a base member provided at a lower end portion of the key stem via a connecting portion, and a post provided on an upper surface of the base member. A U-shaped pressing portion provided on the base member so as to surround the key stem, and a U-shaped leaf spring portion provided on the base member so as to surround the pressing portion. It is characterized by being integrally molded with plastic.

The keyboard switch according to claim 2 is the keyboard switch according to claim 1.
In the keyboard switch described above, the pressing portion, a horizontal portion provided on the upper side of a sound deadening protrusion protruding upward from the upper surface of the base member, and an inclined portion extending obliquely downward from the horizontal portion, And a pressing protrusion provided below the tip of the inclined portion.

The keyboard switch according to claim 3 is the keyboard switch according to claim 1.
In the keyboard switch described, the leaf spring portion,
It has a pair of horizontal portions continuous to the base member, a pair of inclined portions extending obliquely downward from the horizontal portion, and a connecting member that connects the tips of the pair of inclined portions. There is.

A keyboard switch according to a fourth aspect is the keyboard switch according to the third aspect, wherein a spherical protrusion is provided on the lower side of the connecting member, and the spherical protrusion contacts a portion other than the contact portion of the membrane switch. It is characterized by

A keyboard switch according to a fifth aspect is the keyboard switch according to the first aspect, wherein a spherical shape for preventing push-cut noise is provided on a lower side of the base member and a lower side of the key stem opposite to the base member. It is characterized by the provision of a sound deadening protrusion.

[Operation] When the sliding part is pushed down, the pressing projection of the pressing part comes into contact with the contact part of the membrane switch and presses it. In the pressing portion composed of the horizontal portion and the inclined portion, the warp of the inclined portion becomes small, so that the sliding length between the pressing protrusion and the membrane sheet becomes relatively short. Furthermore, if the contact surface of the pressing protrusion is spherical, the abrasion of the sheet of the membrane switch is further reduced. In addition, during the above operation, the leaf spring part bends,
It becomes a mountain shape when pressed. This leaf spring part consisting of the horizontal part and the inclined part has the soundproof protrusion provided on the other part, the tip always contacts the membrane switch, and the entire length effectively acts as a spring. Also, within the limited dimensions, the spring length is longer than the leaf spring consisting of only the horizontal part,
The lifespan will be longer. Further, by connecting the pair of inclined portions with the connecting member, there is no inconvenient difference in the amount of deformation generated in both inclined portions at the time of mold release in integral molding. And excluding the load,
The sliding portion returns upward due to the elastic force of the leaf spring portion, and the impact on the frame is absorbed by the sound deadening protrusion.

[Embodiment] A first embodiment of the present invention will be described with reference to FIGS.

As shown in FIGS. 1 to 3, a keyboard switch 20 of the present embodiment includes a frame 21 which is a base of the switch, a membrane switch 23 which is attached to a lower end surface of the frame 21 by a backing plate 22, A sliding part (24) for pressing a contact part (25) of a membrane switch (23) vertically movable in a frame (21) is provided.

The sliding portion 24 is a member formed by integrally molding plastic as a whole, and has a cylindrical key stem 27 that is vertically slidably guided by a boss-shaped stem guide 26 formed on the upper surface of the frame 21. It is used as a base. Key stem
The key 27 needs to have a length such that its upper end projects outside the frame 21 even when it is pushed in, and a key top 28 is inserted and fixed to the upper end projecting outside the frame 21. Key stem 27
There are two muffler protrusions 29 on one side of the bottom surface of the so that the collision sound can be softened by hitting the membrane switch 23 with a part of the bottom surface when the key stem 27 is pushed down. . Although the key stem 27 has a cylindrical shape, it may of course have a prismatic shape.

At the lower end of the key stem 27, a rod-shaped base member 31 is horizontally provided via a connecting portion 30. The base member 31 is a member for attaching a pressing portion, a leaf spring portion, and a post, which will be described later, and a member for transmitting the movement of the key stem 27 to each of these members. The base member 31 is configured to have an appropriate thickness to obtain rigidity. Therefore, the base member 31 moves in the same manner as the key stem 27, but does not deform. Base member
A pair of sound deadening projections 32 are provided on the lower surface of the 31 to cushion the collision between the sliding portion 24 and the membrane switch 23.

A substantially U-shaped pressing portion 33 having elasticity is formed in a cantilever shape on the base member 31 so as to surround the key stem 27. The pressing portion 33 has a pair of horizontal portions 34 extending horizontally from the base member 31, and an inclined portion 35 extending obliquely downward from the horizontal portion 34. Inclined part 35
A pressing protrusion 36 having a spherical contact portion is formed on the lower surface of the tip of the contact portion 25 so as to contact the contact portion 25 of the membrane switch 23. The inclination angle of the inclined portion 35 is 45.
If the structure is such that the pressing protrusion 36 is provided on the lower surface of the inclined portion 35 extending from the horizontal portion 34, the height of the pressing protrusion 36 can be made shorter than that of a horizontal pressing portion. Therefore, when the contact portion 25 is pressed by pushing down the sliding portion 24, the length in which the pressing protrusion 36 and the membrane switch 23 are in sliding contact can be shortened. Also, the horizontal part
A sound deadening protrusion 37 is provided on the upper surface of 34. The sound deadening protrusion 37 protrudes above the upper surfaces of the base member 31 and the connecting portion 30, and when the entire sliding portion 24 is pushed back upward, it abuts against the upper end surface of the frame 21 and slides. A collision between the moving part 24 and the frame 21 is buffered.

A substantially U-shaped leaf spring portion 38 is formed on the base member 31 so as to surround the pressing portion 33. This leaf spring portion 38 is
The plastic is formed integrally with the base member 31 and the key stem 27, but has appropriate elasticity by appropriately adjusting the thickness and forming a shape inclined obliquely downward. That is, the leaf spring portion 38 has a pair of horizontal portions 39 extending horizontally from the base member 31, and a pair of inclined portions 40 extending obliquely downward from the horizontal portion 39. There is.
The tip end of the pair of inclined portions 40 is a connecting member whose parallel to the base member 31.
41 are connected, and the contact point 25 of the membrane switch 23
It is in contact with other parts. Further, a pair of protrusions 42 is provided on the lower surface of the connecting member 41, and the membrane switch
Wear is prevented by reducing the contact area with 23. As described above, if the leaf spring portion 38 is configured by the horizontal portion 39 and the inclined portion 40, it becomes possible to set the spring length to a large value within the limited allowable dimension in the frame 21, and the stress is dispersed. As a result, the life of the leaf spring portion 38 can be extended. Further, with such a bent shape, the protrusion 42 can always be kept in contact with the membrane switch 23. In addition, the pair of inclined portions 40, 40
With the structure in which the connecting members 41 are integrally connected, in the case of integrally molding with plastic, when the mold is released from the mold, there is no difference in deformation between the two inclined portions 40, 40 in the vertical direction, and the difference in spring property is obtained. It is possible to avoid the inconvenience that

When the sliding portion 24 is incorporated into the frame 21, the leaf spring portion 38 is bent so that the frame 21
The lifting force is applied to the sliding portion 24 inside.

A post 43 is erected on the upper end of the base member 31. The post 43 is parallel to the key stem 27, and its shape may be a cylinder or a prism, but its base and tip have the same diameter. A guide hole 44 is formed in a key portion of the frame 21 corresponding to the post 43. Further, the length of the post 43 needs to be dimensioned such that the post 43 slightly protrudes upward from the guide hole 44 of the frame 21 even when the key stem 27 is completely pressed.
Further, it is necessary that the post 43 be integrally molded with other parts of plastic and have rigidity together with the base member 31 and the key stem 27. According to this configuration, the post
Since the position where 43 is provided is farther from the connecting portion 30 when viewed from the center of the key stem 27, it is possible to prevent the sliding portion 24 from rotating in the horizontal direction.

To assemble the keyboard switch 20 having the above-described structure, first, the sliding portion 24 having an integral structure in which the key top 28 is removed from below the frame 21 is incorporated, and the key stem 27 is inserted into the stem guide 26. The membrane switch 23 and the backing plate 22 are attached to the frame 21 so that the leaf spring portion 38 bends to some extent.
Install on the bottom side of. Then, the key top 28 is attached to the upper end of the key stem 27 protruding to the upper surface side of the frame 21.

Next, the operation of the above configuration will be described.

As shown in FIG. 4 (a), in a state where no load is applied to the switch, the leaf spring portion 38 is slightly bent and the projection 42 is brought into contact with the membrane switch 23.
The entire 24 is urged upward. The sound deadening projection 37 of the pressing portion 33 is in contact with the frame 21.

As shown in FIG. 4B, when the key top 28 (not shown) is pressed with a finger to lower the key stem 27, the leaf spring portion 38 is further bent, and the pressing projection 36 of the pressing portion 33 causes the contact portion 25 of the membrane switch 23. Start pressing.

As shown in FIG. 4C, when the sliding portion 24 is pushed down, the leaf spring portion 38 is deformed into a dogleg shape protruding upward, and the pushing protrusion 36 of the pushing portion 33 is slightly rotated to rotate the membrane switch.
The contact portion 25 is further pressed while rubbing against 23. At this time, the key stem 27 and the base member 31 are brought into contact with the membrane switch 23 by the sound deadening protrusions 29 and 32, so that no loud noise is generated. Further, if there is only one muffling protrusion on the base member 31 side only, the key stem 27 may tilt as shown in FIG. 5 (a), but in the present embodiment, the base member 31 and the key stem 27. And the muffler protrusions 29 are provided on both sides of the base member with respect to the central axis of the key stem 27.
Since it is formed on the side opposite to 31, the key stem 27 does not tilt even when it is completely pressed, as shown in FIG. 5 (b).

Next, except for the load, the sliding portion 24 is returned upward by the elastic force of the leaf spring portion 38. At this time, the sound deadening protrusion 37 of the pressing portion 33
Touches the frame 21 to support the sliding portion 24 and absorb the collision sound.

In the above operation, the key stem 27 is regulated in the positional deviation in the rotation direction by the post 43 and the guide hole 44 which are located at a position considerably separated from the center thereof. Therefore, unlike the conventional rotation restraining structure by the connecting portion 30 of the base member 31,
The post 43 and the guide hole 44 sufficiently help prevent rotation while ensuring a sufficient clearance for sliding.

Further, the pressing portion 33 that presses the contact portion 25 of the membrane switch 23 has a bent shape including the horizontal portion 34 and the inclined portion 35, and the height of the pressing protrusion 36 can be made lower than in the conventional case. Therefore, the sliding contact length between the contact portion 25 and the pressing protrusion 36 can be shortened, and the durability of the portion can be improved.

Further, since the leaf spring portion 38 has a bent shape including the horizontal portion 39 and the inclined portion 40, the effective spring length can be lengthened within a defined space, and the life of the spring can be lengthened. Also, the tip of the leaf spring part 38 is always a membrane switch.
Since it is in contact with 23, it may be plastically deformed into a shape that warps upward. In this case, the entire length of the leaf spring portion 38 cannot be used as a spring, but the tip of the leaf spring portion 38 can always be brought into contact with the membrane switch 23 in the shape of the embodiment.

[Advantage of the Invention] According to the present invention, since the entire sliding portion including the key stem, the base member, the post, the pressing portion, and the leaf spring portion is integrally formed of plastic, the number of parts is remarkably reduced.
The manufacturing cost can be reduced. Besides, according to the present invention, the following effects can be obtained.

(1) Since the pressing portion is composed of the horizontal portion and the inclined portion, the height of the pressing protrusion can be reduced and the warp of the inclined portion can be reduced, resulting in shortening the friction distance of the membrane switch and reducing seat wear. I was able to. Further, by making the contact surface of the pressing protrusion spherical, it was possible to further reduce the wear. As a result, it was possible to improve the reliability of the keyboard switch and extend its life.

(2) Since the leaf spring portion is composed of the horizontal portion and the inclined portion, the spring length can be made longer than the conventional leaf spring having only the inclined portion, and the life can be extended. Further, since the leaf spring portion is deformed into a mountain shape at the time of push-cutting, the tip always comes into contact with the membrane sheet, and the entire length of the spring can be effectively utilized. From this point as well, the life expectancy can be expected to be improved.

(3) By connecting the pair of inclined portions of the leaf spring portion with the connecting member, there is no inconvenient difference in the amount of deformation generated in both inclined portions when the mold is released by integral molding.

(4) If the connecting member is provided with a spherical projection, friction with the membrane switch can be reduced and the life of the membrane switch sheet can be improved.

(5) Since the sound deadening protrusion for preventing the push-cutting noise, which was present in the conventional leaf spring portion, is moved to the lower side of the base member and the key stem, the entire leaf spring portion can be used as a spring, and the life of the leaf spring portion can be increased. Was significantly improved over the past.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention, FIG. 2 is a sectional view of a sliding part and a membrane switch in the same embodiment, and FIG. 3 is a plan view of a sliding part and a membrane switch in the same embodiment. 4 (a), (b), and (c) are cross-sectional views showing the action of the sliding portion in the same embodiment, and FIG. 5 (a) is a case in which there is no silencing protrusion at the lower end of the key stem in the same embodiment. 5 (b) is a sectional view showing a state in which the sliding portion is pushed down in the same embodiment, FIG. 6 is a sectional view showing an example of a conventional keyboard switch, and FIG. FIG. 6 is a cross-sectional view showing an example of a structure for suppressing the rotation of the key stem in the keyboard switch of FIG. 20 …… Keyboard switch, 21 …… Frame, 22 …… Patch plate, 23 …… Membrane switch, 24 …… Sliding part, 27…
… Key stems, 29, 32 …… Sound-proofing protrusions for preventing push-cut noise, 31 …… Base member, 33 …… Pressing part, 34 …… Horizontal part of pressing part, 35 …… Inclined part of pressing part, 36 …… Pressing protrusion, 37 ... mute protrusion, 38 ... leaf spring part, 39 ... horizontal part of leaf spring part,
40 ... Inclined part of leaf spring, 41 ... Connecting member, 42 ... Spherical projection.

Claims (5)

[Scope of utility model registration request] 1. A keyboard switch in which a membrane switch arranged on a backing plate and a sliding portion for pressing the membrane switch are arranged in a frame, and the sliding portion is guided to the frame. A columnar key stem,
A base member provided on the lower end of the key stem via a connecting portion, a post provided on the upper surface of the base member, and a U-shaped pressing portion provided on the base member so as to surround the key stem, A keyboard switch comprising a U-shaped plate spring portion provided on the base member so as to surround the pressing portion, and the sliding portion being integrally molded of plastic. 2. The pressing portion includes a horizontal portion on the upper side of which a sound deadening protrusion protruding above the upper surface of the base member is provided, and an inclined portion extending obliquely downward from the horizontal portion, The keyboard switch according to claim 1, further comprising a pressing protrusion provided below the tip of the inclined portion. 3. The leaf spring portion comprises a pair of horizontal portions continuous to the base member, a pair of inclined portions extending obliquely downward from the horizontal portions, and a tip of the pair of inclined portions. The keyboard switch according to claim 1, further comprising a connecting member to be connected. 4. The keyboard switch according to claim 3, wherein a spherical protrusion is provided on the lower side of the connecting member, and the spherical protrusion is in contact with a portion other than the contact portion of the membrane switch. 5. The keyboard according to claim 1, wherein spherical muffler protrusions for preventing push-cutting noise are provided on the lower side of the base member and the lower side of the key stem opposite to the base member. switch.