JPH038228A - Keyboard switch - Google Patents

Abstract

PURPOSE:To prevent rotation of a key top even when a gap necessary for a key stem to slide is formed by forming a post installed in a base part in parallel to a key stem and a guide hole formed in a frame which guides the post. CONSTITUTION:A post 43 is formed in the end part of an upper plane of a base part 31. The post 43 is in parallel to a key stem 27 and the diameter in the base and the tip part is the same. A guide hole 44 is formed in a key position of a frame 21 corresponding to the post 43. The post 43 needs to have a length enough to project upward from the guide hole 44 of the frame 21 even when the key stem 27 is completely pushed. The post 43 is formed unitedly with other parts from plastics and has toughness with the base part 31 and the key stem. With this structure, the position where the post 43 is formed is farther from the center of the key stem 27 than a connecting part 30 and thus rotary transfer in horizontal direction of a sliding part can be prevented.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a keyboard switch used in a keyboard device such as a computer, typewriter, word processor, etc., and particularly relates to a keyboard switch used in a keyboard device such as a computer, typewriter, word processor, etc. This invention relates to an improvement in a key switch having an opening/closing structure.

[Prior Art] FIG. 7 is a sectional view of a keyboard switch proposed by the present applicant in Utility Application No. 63-48829. As shown in the figure, a membrane switch 3 is fixed to the lower end surface of the open frame l by a backing plate 2. Further, 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. This sliding part 4
A columnar key stem 7 is inserted through a guide hole 6 of a frame 1 and guided in the vertical direction, a key top 8 is attached to the top end of the key stem 7, and a base member is provided at the lower end of the key stem 7. 9 and I]? are provided on the base member 9 so as to surround the key stem 7; It has a pressing part 10 that presses the Meshimembrane Switch 3, and a leaf spring part 11 provided on the base member 9 so as to push back the entire depressed active part 4 in the F direction.

In a keyboard equipped with a large number of keyboard switches with such a configuration, the rotation (backlash) of the key stem 7 is required to keep the key tops 8 arranged side by side in an orderly manner on the frame.
was assisted by the following structure. That is, the eighth
As shown in the figure, a frame 1 that guides the key stem 7
A rotary IF fitting part 12 is formed in the guide hole 6 of the key stem 7.
The connecting portion 13 of the base member 9 is actively engaged with the rotation stopper portion 12.

[Problems to be Solved by the Invention] According to the conventional structure for suppressing the rotation of the key stem 7,
The position of the rotation stopper 12 and the connection part 13 must be set at the center of rotation of the key stem 7, so that the necessary clearance for the key stem 7 to slide up and down must be provided between the rotation stop part 12 and the connection part 13. Even if the gap is the minimum required for sliding of the key stem 7, there is a problem in that the key top 8 will rotate (play). To be more specific, in order for the key stem 7 to slide smoothly, the clearance needs to be 0.05 to 0.11 m on one side, but if such a clearance is provided near the center axis of the key stem 7, rotational play will be reduced. could not be avoided.

SUMMARY OF THE INVENTION An object of the present invention is to provide a keyboard switch equipped with a guide means that can prevent rotation of the key top even if a clearance necessary for sliding of the key stem is set.

[Means for Solving Problems 3] In order to achieve the objects described in C-F, the keyboard switch of the present invention includes a membrane switch disposed on a backing plate, a frame provided above the membrane switch, and a a sliding part that is guided by a frame and presses the membrane switch; a pressing part provided on the base member so as to surround the key stem and pressing the membrane switch; and a plate provided on the base member so as to push up the pressing part, the base member, and the key stem. In a keyboard switch equipped with a spring part,
a post provided on the base member parallel to the key stem;
The post is characterized by having a guide hole provided in the frame for guiding the post.

According to the present invention, in the keyboard switch, the key stem, the base member, and the post of the sliding portion may have rigidity, and the pressing portion and the leaf spring portion may have elasticity. good.

Further, according to the present invention, in the keyboard switch, the Mt recording and moving portion may be integrally molded from plastic.

[Function] The post that slides with respect to the guide hole provided in the frame is provided on the base member provided at the lower end of the key stem via the connecting portion, so the distance from the center of the key stem is equal to the connecting portion. It is larger than the distance between the two. Therefore, even if a gap necessary for sliding is provided between the guide hole and the post, no undesirable rotation (backlash) will occur in the key stem.

[Example] A first example of the present invention will be described with reference to FIGS. 1 to 5.

As shown in FIGS. 1 to 3, the keyboard switch 20 of this embodiment includes a frame 21 that serves as the base of the switch,
Open frame 21'T: Membrane switch 23 attached to the end face with a backing plate 22, and membrane switch 2 provided in the frame 21 so as to be vertically movable.
It has a sliding part 24 for pressing the contact part 25 of No. 3.

The sliding portion 24 is a member formed by molding a plastic body as a whole, and has a cylindrical shape that is guided by a boss-like stem guide 26 formed on the −F surface of the frame 21 so as to be able to freely slide upward. The key stem 27 is used as a base. The key stem 27 needs to be long enough for its upper end to protrude outside the frame 21 even when pressed, and a key top 28 is inserted and fixed to one F end that protrudes outside the frame 21. Two eraser protrusions 29 are provided on the bottom side of the key stem 27, so that when the key stem 27 is pressed down, a part of the bottom hits the membrane switch 23, thereby softening the collision force. It has become.

Although the key stem 27 has a cylindrical shape, a rod-shaped base member 31 is provided horizontally at the lower end of the key stem 27, which may of course be prismatic. This base member 31 is a member for attaching a pressing portion, a leaf spring portion, and a post to be described later, and is also 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 in order to obtain rigidity. Therefore, the base member 31 moves in the same manner as the key stem 27, but is not deformed. A pair of sound-muffling protrusions 32 are provided on the lower surface of the base member 31 to buffer collisions between the sliding portion 24 and the membrane switch 23.

On the surface base member 31, an elastic, substantially U-shaped pressing portion 33 is formed in a cantilever shape so as to surround the periphery of the key stem 27 [#7]. This pressing portion 33
a pair of horizontal parts 34 extending horizontally from the horizontal part 3;
4 and an inclined portion 35 extending obliquely downward from the portion 4. A pressing protrusion 36 having a spherical contact portion is formed on the lower surface of the tip of the inclined portion 35, and is adapted to come into contact with the contact portion 25 of the membrane switch 23. The angle of inclination of the inclined part 35 is preferably within 45 degrees, and the structure in which the pressing protrusion 36 is provided on the lower surface of the inclined part 35 extending from the horizontal part 34 is more convenient than the pressing part horizontal to the funeral. The height of the pressing protrusion 36 can be shortened, and the sliding part 2
When the contact portion 25 is pressed by pressing down the membrane switch 4, the length of the sliding contact between the pressing protrusion 36 and the membrane switch 23 can be shortened. Furthermore, a sound muffling protrusion 37 is provided on the upper surface of the horizontal portion 34 . The sound muffling protrusion 37 protrudes one level above the upper surfaces of the surface base member 31 and the connecting portion 30, and comes into contact with the upper end surface of the frame 21 when the entire sliding portion 24 is pushed back upwards. This cushions the collision between the sliding portion 24 and the frame 21.

A substantially U-shaped plate spring portion 38 is formed on the surface base member 31 so as to surround the pressing portion 33 . This leaf spring part 38 is made of plastic molded integrally with the base member 31 and the key stem 27, and by appropriately adjusting the thickness and slanting the shape diagonally downward, it is made to have appropriate elasticity. It is. That is, this plate spring portion 38 includes a pair of horizontal portions 39 extending horizontally from the base member 31;
It has a pair of inclined parts 40 extending obliquely downward from the horizontal part 39. The tips of the pair of inclined portions 40 are connected to the base member 31 by a connecting member 41 that is substantially parallel, and are in contact with a portion of the membrane switch 23 other than the contact portion 25 . Further, a pair of protrusions 4 are provided on the lower surface of this connecting member 41.
2 is provided to prevent wear by reducing the contact area with the membrane switch 23. In this way, the horizontal part 39 and the inclined part 40 make the leaf spring part 3
8, it becomes possible to set the spring length extremely within the limited allowable dimensions within the frame 21, and the life of the leaf spring portion 38 can be extended by dispersing stress. can. Further, by forming the protrusion 42 into such a bent shape, the protrusion 42 can be kept in contact with the membrane switch 23 at all times. Further, a pair of inclined portions 40.
40 are integrally connected by the connecting member 41, when integrally molded with plastic, there is no difference in vertical deformation of the two inclined parts 40, 40 when the mold is released from the mold, and the spring property is improved. The inconvenience of differences can be avoided.

In addition, when incorporating the sliding part 24 into the frame 21,
No. 111, so that the leaf spring portion 38 is in a bent state,
A holding force is applied to the sliding part 24 within the frame 21.

A post 43 is provided upright at the end of the L surface of the base member 31 . The boss 43 is parallel to the key stem 27, and may have a cylindrical or prismatic shape, but its base and tip have the same diameter. A guide hole 44 is formed at a key point of the frame 21 corresponding to the boss 43. The length of the boss 43 must be such that even if the key stem 27 is pushed all the way, it still protrudes upward from the guide hole 44 of the frame 21 to some extent. Further, the boss 43 is integrally molded of plastic with other parts, and needs to have rigidity together with the base member 31 and the key stem 27. According to this configuration, since the position where the post 43 is provided is further away than the connecting portion 30 when viewed from the center of the key stem 27, rotational movement of the sliding portion 24 in the horizontal direction can be prevented.

To assemble the keyboard switch 20 configured as described above, first install the integrated sliding part 24 with the key tops 28 removed from the bottom of the frame 21, and then attach the key stem 27.
into the stem guide 26. And the leaf spring part 38
The membrane switch 23 and the backing plate 22 are attached to the lower surface side of the frame 21 so that the membrane switch 23 and the backing plate 22 are bent to some extent. Then, a key top 28 is attached to the upper end of the key stem 27 that protrudes toward the upper surface side of the frame 21.

Next, the operation of the configuration described below will be explained.

As shown in FIG. 4(a), when no load is applied to the switch, the leaf spring portion 38 is slightly bent and the protrusion 42 is in contact with the membrane switch 23, and the sliding The entire moving part 24 is pushed upward. The γ-erasing protrusion 37 of the pressing portion 33 is in contact with the frame 21.

As shown in FIG. 4(b), the key top 28 (not shown)
When the key stem 27 is pressed with a finger, the plate spring portion 38 is further bent, and the suppressing protrusion 36 of the pressing portion 33 begins to press the contact portion 25 of the membrane switch 23.

As shown in FIG. 4(C), when the sliding part 24 is pushed completely downward, the leaf spring part 38 is deformed into a dogleg shape that projects upward, and the pressing protrusion 36 of the pressing part 33 rotates slightly to remove the membrane. While rubbing against the switch 23, the contact portion 25 is further pressed. At this time, the key stem 27 and the base member 31 are
Since the membrane switch 23 is contacted by the contacts 9 and 32, no loud noise is generated. Furthermore, if there is only one sound muffling protrusion, for example, only on the base member 31 side, the key stem 27 may be tilted as shown in FIG. 5(b), the key stem 27 is tilted even when it is pushed out, as shown in FIG. 5(b). Never.

Next, when the load is removed, the sliding portion 24 returns upward due to the elastic force of the leaf spring portion 38. At this time, the sound muffling protrusion 37 of the pressing part 33 comes into contact with the frame 21 and supports the sliding part 24,
Absorbs collision sound.

In the above operation, the key stem 27 is prevented from shifting in the rotational direction by the boss 43 and the guide hole 44 located at a considerable distance from the center of the key stem 27. Therefore, unlike the conventional rotation prevention structure using the connecting portion 30 of the base member 31, the boss 43 and the guide hole 44 are sufficient for sliding movement and are sufficiently useful for preventing rotation while ensuring rearance.

Further, the pressing portion 33 that presses the contact portion 25 of the membrane switch 23 has a bent shape consisting of a horizontal portion 34 and an inclined portion 35, and the height of the pressing protrusion 36 can be lowered compared to the conventional one. Therefore, the contact length between the contact portion 25 and the pressing protrusion 36 can be shortened, and the durability of this portion can be improved.

Further, since the leaf spring portion 38 has a bent shape consisting of a horizontal portion 39 and an inclined portion 40, the effective spring length can be increased within a defined space, and J? It is possible to prolong your life. Further, since the tip of the leaf spring portion 38 is always in contact with the membrane switch 23, it may be plasticized into a shape that is warped in the −F direction. In this case, the entire length of the leaf spring section 38 cannot be used as a spring, or the tip of the leaf spring section 38 can always be brought into contact with the membrane switch 23 if the shape is as in the embodiment.

In the embodiment described above, the entire sliding portion 24 may be integrally molded of plastic, or only the leaf spring portion may be made of metal. For example, as shown in the second embodiment shown in FIG. 6, the leaf spring section 50 is not provided with a connecting member, and a pair of water! The leaf spring part 50 consisting of the F part 51 and the inclined part 52 is formed of stainless steel or phosphor bronze, and when molding the plastic key stem 55, base member 53, and pressing part 33, the leaf spring part 50 is made of plastic by insert molding. Construct integrally with the parts. In this case as well, a protrusion 54 may be provided at the tip of the inclined portion 52 to prevent wear of the membrane switch. Further, in this embodiment, one or a pair of sound muffling protrusions 56 are provided on the lower end surface of the key stem 55.

[Effects of the Invention] As described above, according to the present invention, the post is provided at a position of the base member remote from the center of the key stem, and the post is guided to the guide hole of the frame, so that the key stem This has the effect of being able to reliably suppress the rotation of.

[Brief explanation of the drawing]

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. , FIG. 4(a). (b) and (c) are cross-sectional views showing the action of the sliding part in the same embodiment, FIG. FIG. 5(b) is a cross-sectional view showing the sliding part in the same embodiment with the sliding part fully pressed, FIG. 6 is a plan view of the sliding part in the second embodiment of the present invention, and FIG. 7 is a view of a conventional keyboard switch. FIG. 8 is a sectional view showing an example of a structure for suppressing rotation of a key stem in a conventional keyboard switch. 20... Keyboard switch, 21... Frame,
22... Backing plate, 23... Membrane switch, 2
4... Sliding part, 27... Key stem, 30... Series connection part, 3I... Base member, 33... Pressing part, 38...
Leaf spring portion, 43...post, 44...guide hole. Figure 3 Blade 4

Claims (1)

[Scope of Claims] 1. It has a membrane switch arranged on a backing plate, a frame provided above the membrane switch, and a sliding part that is guided by the frame and presses the membrane switch, The sliding portion includes a columnar key stem guided by a frame, a base member provided at the lower end of the key stem via a connecting portion, and a membrane switch provided on the base member so as to surround the key stem. A keyboard switch comprising: a pressing part that presses the base member; a leaf spring part provided on the base member so as to push up the pressing part, the base member, and the key stem; A keyboard switch comprising: a post provided therein; and a guide hole provided in a frame for guiding the post. 2. The keyboard switch according to claim 1, wherein the key stem, the base member, and the post of the sliding portion have rigidity, and the pressing portion and the leaf spring portion have elasticity. 3. The keyboard switch according to claim 1 or 2, wherein the sliding portion is integrally molded from plastic.