1. Field of the Invention
The present invention relates to a key switch device, and a method of manufacturing a key switch device.
2. Description of the Related Art
Thin keyboards are desirable for electronic devices such as notebook personal computers or the like, for example. Thus, key switch devices mounted on the keyboard are desired to have low height. For such a purpose, a key switch device including a key top, a pair of gear links having a “V” shape, a membrane sheet switch and a support plate is provided, as disclosed in Patent Documents 1 and 2, for example.
In the key switch device disclosed in Patent Document 1 or 2, the key top fits the gear links by pressing and fitting hooks of the key top and sliding pins of the gear links. However, when inserting the key top, in other words, before fitting the hooks of the key top and the sliding pins of the gear links, the gear links are positioned at a bottom dead center. Thus, it is necessary to attach the key top while pressing a rubber dome of the membrane sheet switch in order to fit the key top and the gear links.
In such a case, when inserting the key top, as the key top first contacts the unstable rubber dome before contacting the gear links that function as a fixing guide, it is hard to align the position of the key top, and as a result, it is hard to insert the key top. Further, as it is hard to align the position of the key top, an operator needs to be skilled in inserting the key top. Thus, the gear links may be damaged by an unskilled operator.
When inserting the key top, it is necessary to match centers of the rubber dome and the gear links while adjusting positions of the rubber dome and the gear links. However, if the position of the key top is shifted in a lateral direction, it is necessary to correct the position of the key top in the lateral direction while fitting the key top to the gear links. At this time, deformation of the rubber dome easily occurs.
If the rubber dome deforms largely, there may be an unusual feeling in a manufactured key switch device such as a click feeling cannot be obtained, or the click feeling is too small in a keying operation. Thus, a problem may be generated such as percent defective is increased, test steps are increased, deficiency when using the key switch device is generated or the like.
Further, measures in order to prevent the deformation of the rubber dome, such as improving the skill of the operator in inserting the key top, or pulling up the key top when inserting the key top or the like, also cause an increase of manufacturing steps and an increase of cost.
Recently, as a demand for thin keyboards for electronic devices is increasing, the size of the rubber dome is becoming small. Thus, the problem of the deformation of the rubber dome happens more often. It is difficult to form the rubber dome with a small size to be capable of retaining the click feeling while retaining the resistance against a force in the lateral direction.
Further, for a key switch device, there is a demand to reduce a keying sound that is generated while operating the key switch device. Conventionally, the key switch device is configured to reduce the sound generated in a keying operation by an elasticity of the rubber dome when it is compressed at a stroke end. However, as the size of the rubber dome becomes small and the stroke is shortened, it is hard to reduce the sound generated in a keying operation because there is not enough space for the compression of the rubber dome.
According to an embodiment, there is provided a key switch device including a key top; a link member that guides an elevating operation of the key top while being interlocking with the key top, the link member including a rotatable shaft and a sliding shaft that is connected to the key top; a membrane sheet that includes a contact that opens and closes in accordance with the elevating operation of the key top; a back plate; a housing that holds the rotatable shaft of the link member to the back plate; and a pushing unit that pushes the link member such that the sliding shaft moves away from the back plate.
According to another embodiment, there is provided a method of manufacturing a key switch device including, a key top, a link member that guides an elevating operation of the key top, the link member including a rotatable shaft and a sliding shaft that is connected to the key top, a membrane sheet that includes a contact that opens and closes in accordance with the elevating operation of the key top, a back plate, and a housing that holds the rotatable shaft of the link member to the back plate, the method including: pushing the link member such that the sliding shafts moves away from the back plate.
According to another embodiment, there is provided a key switch device including a key top; a link member that guides an elevating operation of the key top, the link member including a rotatable shaft and a sliding shaft that is connected to the key top; a membrane sheet that includes a contact that opens and closes a contact in accordance with the elevating operation of the key top; a back plate; and a housing that holds the rotatable shaft of the link member to the back plate, wherein the back plate is provided with a through hole at a position corresponding to the link member near the rotatable shaft.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.
The invention will be described herein with reference to illustrative embodiments. Those skilled in the art will recognize that many alternative embodiments can be accomplished using the teachings of the present invention and that the invention is not limited to the embodiments illustrated for explanatory purposes.
It is to be noted that, in the explanation of the drawings, the same components are given the same reference numerals, and explanations are not repeated.
With reference to
It is defined that an upper side of the key top 2 in
The gear links 3 are connected to the key top 2 and guide an elevating operation of the key top 2 while interlocking with the key top 2. Each of the gear links 3 includes rotatable pins 31 (an example of a rotatable shaft) and a pair of flat springs 32 (an example of a pushing unit). The membrane sheet 4 includes contacts each of which corresponds to any of the key top 2. Each contact opens and closes in accordance with the elevating operation of the respective key top 2. The back plate 5 is stacked on the membrane sheet 4 at the back surface side of the membrane sheet 4. The housing 6 mounts and holds the rotatable pins 31 of the gear links 3 to the back plate 5. The pair of flat springs 32 push the respective gear link 3 from the back surface side by an urging force (pushing force) when the gear link 3 is rotated closer to the back plate 5 while having the rotatable pin 31 as a rotatable shaft.
The key top 2 is a saucer-like member having a rectangular shape when seen in a plan view, for example.
The housing 6 is a frame member having a rectangular shape when seen in a plan view, for example. The housing 6 includes two pairs of bearing portions 61 and four leg portions 62. The two pairs of bearing portions 61 are provided at the back surface side of the housing 6 and rotatably support the rotatable pins 31 of the gear links 3, respectively. The leg portions 62 are provided to protrude from four corners of the housing 6 to align and fix the housing 6 to the back plate 5. The gear links 3 have the same shape and the same size. The key top 2, the housing 6 and the gear link 3 may be formed by a resin material such as acrylonitrile butadiene styrene resin (ABS) or the like, for example.
The gear link 3 has a “U” shaped frame including a first arm portion 3a, a second arm portion 3b and a connection portion 3c connecting the first arm portion 3a and the second arm portion 3b. Here, a space formed between the first arm portion 3a and the second arm portion 3b is referred to as an “opening”.
The gear link 3 further includes the rotatable pins 31, the flat springs 32, a sliding pin 34 (an example of a sliding shaft), and a first teeth portion 35 and a second teeth portion 36. The rotatable pins 31 protrude from an inner side of the “U” shaped frame of the gear link 3.
The flat springs 32, each having a flat plate shape, are respectively provided at the first arm portion 3a and the second arm portion 3b. One end of each of the flat springs 32 is connected to the first arm portion 3a or the second arm portion 3b at a position outside of the rotation center of the rotatable pin 31 in a radial direction to extend in a direction away from the respective rotatable pin 31 while being apart from the respective first arm portion 3a or the second arm portion 3b. The flat springs 32 may be integrally formed with the gear link 3 or alternatively, may be separately formed by a metal material, or other elastic material, and attached to the gear link 3.
Further, the first arm portion 3a and the second arm portion 3b are provided with concave portions 33. The flat spring 32 is housed to the concave portion 33 when the flat spring 32 is deflected as the gear link 3 contacts the back plate 5.
The sliding pin 34, extending along the connection portion 3c, is provided at the connection portion 3c. The sliding pin 34 outwardly protrudes from the connection portion 3c.
The connection portion 3c is configured to extend in a rotation axis direction of the rotatable pin 31. Thus, the sliding pin 34 is also configured to extend in the rotation axis direction of the rotatable pin 31.
The first teeth portion 35 includes a single tooth and is provided at a front end of the first arm portion 3a. The second teeth portion 36 includes two teeth and is provided at a front end of the second arm portion 3b.
When the openings of two gear links 3 are faced toward each other, the first teeth portion 35 of one of the gear links 3 engages the second teeth portion 36 of the other of the gear links 3, and the second teeth portion 36 of one of the gear links 3 engages the first teeth portion 35 of the other of the gear links 3.
With reference to
Referring back to
The membrane sheet 42 may be made of a resin material such as polyethlene terephthalate (PET) or the like, for example. The rubber dome 41 may be made of an elastic resin material such as a rubber or the like.
The back plate 5 is stacked on the back surface side of the membrane sheet 42. The back plate 5 of the first embodiment is a support plate made of a metal plate such as a sheet metal, stainless steel or the like. The back plate 5 is provided with hole portions 51 respectively corresponding to the leg portions 62 of the housing 6. The hole portions 51 are formed by punching the back plate 52 from its back surface side. Each of the hole portions 51 has a partially conical shape protruding toward the front surface side to be tapered in the front surface side.
The key switch device 1 of the first embodiment is manufactured as follows.
With reference to
Thereafter, the housing 6 is stacked on the gear links 3 from the front surface side. At this time, the rotatable pins 31 are inserted in the bearing portions 61, respectively, and the leg portions 62 are inserted in the hole portions 51, respectively. With this configuration, positions of the housing 6, the gear links 3, the membrane sheet 4 and the back plate 5 are determined. Then, the back surface side of the housing 6 is bonded to the front surface side of the back plate 5 by adhesive.
An end of each of the leg portions 62 that protrudes toward the back surface side is deformed by heat caulking and the ends of the deformed leg portions 62 are housed and fixed in the hole portions 51, respectively, for example. This operation of heat caulking may be performed at an appropriate timing after the key top 2 is attached. When the ends of the leg portions 62 are deformed by heat caulking, the back surface side of the housing 6 may not be bonded to the front surface side of the back plate 5 by the adhesive.
As illustrated in
The height of the sliding pin 34 from the front surface of the membrane sheet 4 at the standing state, before the key top 2 is attached as illustrated in
As the standing state is retained as described above, when pressing and fitting the hook 21b in the sliding pin 34b, a deflecting amount of the rubber dome 41 can be minimized.
As described above, according to the first embodiment, a deflecting amount of the rubber dome 41 can be minimized when attaching the key top 2 to the gear links 3 by pressing and fitting the hooks 21 of the key top 2 to the respective sliding pins 34 of the gear links 3. Thus, an operator can easily perform an alignment or a pressing and fitting operation of the key top 2 with respect to the gear links 3 without a specific skill. Further, the unusual feeling of the rubber dome 41 or the like can also be prevented.
Further, the flat springs 32 are used when manufacturing the key switch device 1 of the first embodiment.
A keyboard of the embodiment includes a plurality of the key switch devices 1 aligned in a predetermined pattern that is the same as known keyboards, thus, the keyboard of the embodiment is not illustrated in the drawings.
A keying operation is explained with reference to
The urging force of the flat springs 32 become stronger as the key top 2 is pressed deeper. Thus, a keying sound that is generated when the hook 21 or the like provided at the back surface of the key top 2 contacts with the back plate 5 via the opening portion 42a of the membrane sheet 42, can be minimized.
In the second embodiment, the back plate 5 is a thin film sheet made of a resin material such as polyethlene terephthalate (PET) or the like. The thin film sheet is provided with protruding portions 52 (an example of a protrusion).
In this embodiment, the protruding portions 52 are formed in the back plate 5 at positions corresponding to areas “S” (see
These protruding portions 52 of the second embodiment function as a pushing unit. The protruding portions 52 push the arm portions 3a 3b of the gear links 3 while contacting the concave portions 33 of the gear links 3, by an elasticity of the thin film sheet. Specifically, the protruding portions 52 push the respective gear link 3 from the back surface side by an urging force stored in the protruding portions 52 when the gear links 3 are rotated closer to the back plate 5 around the rotatable pins 31, respectively.
As described above, as the protruding portions 52 of the back plate 5 function as a pushing unit, the urging force by the protruding portions 52 push bottom surfaces of the concave portions 33 of the gear links 3 from the back surface side, respectively. Thus, as illustrated in
As this standing state is retained, as illustrated in
As described above, according to the second embodiment, similar to the first embodiment, the deflecting amount of the rubber dome 41 can be decreased when attaching the key top 2 to the gear links 3. Thus, an operator can easily perform an alignment or a pressing and fitting operation of the key top 2 with respect to the gear links 3 without a specific skill. Further, the unusual feeling of the rubber dome 41 or the like can also be prevented.
Further, the key switch device 1 of the second embodiment can be manufactured by composing the back plate 5 by the thin film sheet provided with the protruding portions 52.
Similar to the first embodiment, a keyboard of the second embodiment includes the key switch devices 1 aligned in a predetermined pattern that is the same as known keyboards, thus, the keyboard of the embodiment is not illustrated in the drawings.
A keying operation is explained with reference to
In this embodiment, the urging force of the protruding portions 52 become stronger as the key top 2 is pressed deeper. Thus, similar to the first embodiment, a keying sound that is generated when the hook 21 or the like provided at the back surface of the key top 2 contacts with the back plate 5 via the opening portions 42a of the membrane sheet 42, can be minimized.
The protruding portions may be formed in the membrane sheet 42 instead of being formed in the back plate 5 as explained above in the second embodiment.
According to the third embodiment, the same advantage can be obtained as the second embodiment.
In this embodiment, the key switch device 101 is different from the key switch device 1 of the first to third embodiments in that the key switch device 101 does not include the pushing unit such as the flat springs 32, the protruding portions 52 or the protruding portions 43. Instead, according to the fourth embodiment, the key switch device 101 is manufactured using a jig provided with the pushing unit.
As illustrated in
As illustrated in
As described above, the pins 103 pushed by the springs 104 of the jigs 102 push the bottom surfaces of the concave portions 33 of the gear links 3 from the back surface side, respectively. Thus, as illustrated in
As this standing state is retained, as illustrated in
As described above, according to the fourth embodiment, similar to the first to third embodiments, the deflecting amount of the rubber dome 41 can be decreased when attaching the key top 2 to the gear links 3. Thus, an operator can easily perform an alignment or a pressing and fitting operation of the key top 2 with respect to the gear links 3 without a specific skill. Further, the unusual feeling of the rubber dome 41 or the like can also be prevented.
Further, the key switch device 101 of the fourth embodiment is manufactured by providing the through holes 53 to the back plate 5 while using the jig 102 provided with the pins 103 that penetrate the through holes 53, respectively, and springs 104 that push the pins 103, respectively, from the back surface side.
Similar to the first embodiment, a keyboard of the embodiment includes a plurality of the key switch devices 101 aligned in a predetermined pattern that is the same as known keyboards, thus, the keyboard of the embodiment is not illustrated in the drawings.
In the fourth embodiment, the jig 102 including the pushing unit is removed from the final product. When the key switch device 101 is not pressed, the key top 2 and the sliding pins 34 of the gear links 3 are retained at a top dead center by the elastic force of the rubber dome 41. Then, when the keying operation is performed and the key top 2 is pressed against the elastic force of the rubber dome 41, the key top 2 is moved to a bottom dead center.
According to the embodiments, even before attaching the key top, the link members can be retained at the standing position. Therefore, positions of the key top and the link members can be easily matched when attaching the key top to the sliding shafts of the link members. Therefore, according to the embodiments, manufacturing steps of the key switch device can be reduced and the cost can also be reduced.
Further, a keying sound can be reduced because contact of the key top, mainly hooks or an outer end portion thereof, with the back plate at a stroke end in a keying operation can be suppressed as an urging force of the pushing unit is added to an elastic force of the rubber dome generated when the rubber dome is compressed.
The present embodiments relate to a key switch device for inputting data by a keying operation, a keyboard, and a method of manufacturing the key switch device. As problems such as the unusual feeling can be suppressed without increasing manufacturing steps or increasing a burden to an operator according to the embodiments, the embodiments can be applied to various electronic devices.
Although a preferred embodiment of the key switch device, a keyboard, and a method of manufacturing the key switch device has been specifically illustrated and described, it is to be understood that minor modifications may be made therein without departing from the spirit and scope of the invention as defined by the claims.
The present invention is not limited to the specifically disclosed embodiments, and numerous variations and modifications and modifications may be made without departing from the spirit and scope of the present invention.
The present application is based on and claims the benefit of priority of Japanese Priority Application No. 2012-253570 filed on Nov. 19, 2012, the entire contents of which are hereby incorporated by reference.
Number | Date | Country | Kind |
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2012-253570 | Nov 2012 | JP | national |