Abstract:
A keyswitch includes a base plate, a cap having a longitudinal axis, a returning device, a support mechanism, and a lifting mechanism including first and second support plates. The first support plate has first and second edges parallel to the longitudinal axis for respectively abutting against the base plate and the cap. The second support plate has third and fourth edges parallel to the longitudinal axis for respectively abutting against the base plate and the cap. The base plate is disposed through openings of the first and second support plates to make the first and second support plates movably connected to the base plate. The returning device drives the cap to a non-pressed position with rotation of the first and second support plates. The support mechanism has first and second support members pivoted to each other to be movably connected to the cap and the base plate.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
       [0001]    The present invention relates to a keyswitch, and more specifically, to a keyswitch utilizing a support mechanism located between a first support plate and a second support plate to be movably connected to a cap and a base plate for increasing a pull-out force of the cap. 
       2. Description of the Prior Art 
       [0002]    A keyboard, which is the most common input device, can be found in variety of electronic apparatuses for users to input characters, symbols, numerals and so on. Furthermore, consumer electronic products and industrial machine tools are all equipped with a keyboard for performing input operations. 
         [0003]    A stroke of a cap of a conventional keyswitch is relatively long, so it is easy to dispose a rubber dome under the cap so that when the cap is pressed to move downward, the rubber dome is deformed and produces resilient force, and when the cap is released, the resilient force drives the cap to move upward to its original position. However, with a tendency toward keyboard miniaturization, the stroke of the cap is required to decrease, so the height of the rubber dome is also required to decrease. The service life and the resilient force of the keyswitch decays with a decreasing height of the rubber dome. Furthermore, for a keyswitch with a longer length (or called a multiple-width keyswitch), a plurality of links is disposed under the cap so that the cap can remain horizontally while being moved up and down by a user pressing any portion of the cap, and the user can feel a distinct force feedback (or tactile feedback). However, if the height of the cap is required to decrease more, the aforesaid design may not be accomplished easily due to space constraint. Moreover, the aforesaid link connection design can also reduce the pull-out force of the cap to cause the problem that the cap could fall off easily. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention provides a keyswitch. The keyswitch includes a base plate, a cap, a lifting mechanism, a returning device, and at least one support mechanism. The cap has a longitudinal axis. The lifting mechanism is disposed between the base plate and the cap. The cap is movable between a pressed position and a non-pressed position relative to the base plate via the lifting mechanism. The lifting mechanism includes a first support plate and a second support plate coupled to each other. The first support plate has at least one first opening. The base plate is partially disposed through the at least one first opening to make the first support plate movably connected to the base plate. The first support plate has a first edge and a second edge. The first edge abuts against the base plate. The second edge is opposite to the first edge and abuts against the cap. The first edge and the second edge are parallel to the longitudinal axis. The second support plate has at least one second opening. The base plate is partially disposed through the at least one second opening to make the second support plate movably connected to the base plate. The second support plate has a third edge and a fourth edge. The third edge abuts against the base plate. The fourth edge is opposite to the third edge and abuts against the cap. The third edge and the fourth edge are parallel to the longitudinal axis. The returning device is located between the first support plate and the second support plate for providing a returning force to drive the cap to move from the pressed position back to the non-pressed position with rotation of the first support plate relative to the base plate via the first edge and rotation of the second support plate relative to the base plate via the third edge. The at least one support mechanism is located between the first support plate and the second support plate. The at least one support mechanism has a first support member and a second support member. The first support member is movably connected to the cap and the base plate. The second support member is movably connected to the cap and the base plate and is pivoted to the first support member. 
         [0005]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a diagram of a keyswitch according to an embodiment of the present invention. 
           [0007]      FIG. 2  is a cross-sectional diagram of the keyswitch in  FIG. 1  along a cross-sectional line A-A. 
           [0008]      FIG. 3  is a cross-sectional diagram of a cap in  FIG. 2  being pressed to a pressed position. 
           [0009]      FIG. 4  is an enlarged diagram of a first support plate and a second support plate in  FIG. 1  from another viewing angle. 
           [0010]      FIG. 5  is an exploded diagram of a base plate, the cap, and a support mechanism in  FIG. 1 . 
           [0011]      FIG. 6  is a partial enlarged exploded diagram of the keyswitch in  FIG. 1 . 
           [0012]      FIG. 7  is a diagram of a keyswitch according to another embodiment of the present invention. 
           [0013]      FIG. 8  is a cross-sectional diagram of the keyswitch in  FIG. 7  along a cross-sectional line B-B when the cap is pressed. 
           [0014]      FIG. 9  is an assembly diagram of the cap, the first support plate and the second support plate according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Please refer to  FIG. 1 , which is a diagram of a keyswitch  10  according to an embodiment of the present invention. For clearly showing the internal mechanical design of the keyswitch  10 , a cap  14  is depicted by dotted lines in  FIG. 1 . As shown in  FIG. 1 , the keyswitch  10  could preferably be a keyswitch with a longer length (also called a multiple-width keyswitch) and includes a base plate  12 , the cap  14 , a lifting mechanism  16 , a returning device  18 , and at least one support mechanism  20  (two shown in  FIG. 1 , but not limited thereto). The cap  14  has a longitudinal axis L. The lifting mechanism  16  is disposed between the base plate  12  and the cap  14 . The cap  14  can move between a pressed position and a non-pressed position relative to the base plate  12  via the lifting mechanism  16 . The lifting mechanism  16  includes a first support plate  22  and a second support plate  24 . The first support plate  22  and the second support plate  24  are coupled to each other. The first support plate  22  has at least one first opening  26  (five shown in  FIG. 1 , but not limited thereto). The base plate  12  is partially disposed through the first opening  26  to make the first support plate  22  movably connected to the base plate  12 . The first support plate  22  has a first edge  28  and a second edge  30 . The first edge  28  abuts against the base plate  12  to make the first support plate  22  rotatable relative to the base plate  12  via the first edge  28 . The second edge  30  is opposite to the first edge  28  and abuts against the cap  14 . The first edge  28  and the second edge  30  are parallel to the longitudinal axis L to make the first support plate  22  strip-shaped. The second support plate  24  has at least one second opening  32  (two shown in  FIG. 1 , but not limited thereto). The base plate  12  is partially disposed through the second opening  32  to make the second support plate  24  movably connected to the base plate  12 . The second support plate  24  has a third edge  34  and a fourth edge  36 . The third edge  34  abuts against the base plate  12  to make the second support plate  24  rotatable relative to the base plate  12  via the third edge  34 . The fourth edge  36  is opposite to the third edge  34  and abuts against the cap  14 . The third edge  34  and the fourth edge  36  are parallel to the longitudinal axis L to make the second support plate  22  strip-shaped. 
         [0016]    To be more specific, the first edge  28  could have a first middle section  38  and a first tail section  40 . The first middle section  38  is close to a center point C of the longitudinal axis L. The first tail section  40  is close to a terminal point P of the longitudinal axis L. The third edge  34  could have a second middle section  42  and a second tail section  44 . The second middle section  42  is close to the center point C of the longitudinal axis L. The second tail section  44  is close to the terminal point P of the longitudinal axis L. The first tail section  40  is away from the second tail section  44  forming a containing space  46 . The support mechanism  20  is disposed in the containing space  46 . In practical application, the first support plate  22  could further have a containing slot  48  and an auxiliary edge  50  corresponding to the support mechanism  20 . The support mechanism  20  is partially contained within the containing slot  48 . The auxiliary edge  50  extends outwardly from the containing slot  48  to be located at an outer side of the support mechanism  20  away from the returning device  18  and abuts against the base plate  12 . Accordingly, the first support plate  22  can rotate steadily relative to the base plate  12  via the first edge  28  and the auxiliary edge  50  to improve the tactile feedback of the keyswitch  10 . 
         [0017]    The returning device  18  is located between the first support plate  22  and the second support plate  24  for providing a returning force to drive the cap  14  to move from the pressed position back to the non-pressed position with rotation of the first support plate  22  relative to the base plate  12  via the first edge  28  and rotation of the second support plate  24  relative to the base plate  12  via the third edge  34 . In this embodiment, the returning device  18  could preferably adopt the magnetic attraction design. For example, please refer to  FIG. 1 ,  FIG. 2 , and  FIG. 3 .  FIG. 2  is a cross-sectional diagram of the keyswitch  10  in  FIG. 1  along a cross-sectional line A-A.  FIG. 3  is a cross-sectional diagram of the cap  14  in  FIG. 2  being pressed to the pressed position. As shown in  FIG. 1 ,  FIG. 2 , and  FIG. 3 , the returning device  18  includes a first magnetic member  52  and a second magnetic member  54 . The first magnetic member  52  extends from the first edge  28  toward the second support plate  24 . The second magnetic member  54  is disposed on the base plate  12  corresponding to the first magnetic member  52 . Accordingly, the first magnetic member  52  can magnetically attract the second magnetic member  54  to generate the returning force. When the cap  14  is not pressed, the returning force keeps the cap  14  at the non-pressed position as shown in  FIG. 2 . When the cap  14  is pressed by an external force to make the first magnetic member  52  separate from the second magnetic member  54  with rotation of the first support plate  22  relative to the base plate  12  via the first edge  28 , the cap  14  moves from the non-pressed position as shown in  FIG. 2  to the pressed position as shown in  FIG. 3  with the lifting mechanism  16  performing the triggering operation to execute a corresponding input function. On the other hand, when the external force is released, the returning force makes the first magnetic member  52  return to be adjacent the second magnetic member  54 . Accordingly, the cap  14  could move from the pressed position as shown in  FIG. 3  back to the non-pressed position as shown in  FIG. 2  with the lifting mechanism  16 , so that the cap  14  could automatically return to its original position. 
         [0018]    Please refer to  FIGS. 1-4 .  FIG. 4  is an enlarged diagram of the first support plate  22  and the second support plate  24  in  FIG. 1  from another viewing angle. As shown in  FIGS. 1-4 , the keyswitch  10  could further include a membrane circuit board  56 . The membrane circuit board  56  is disposed on the base plate  12  and has at least one first triggering switch  58  (one shown in  FIG. 2 , but not limited thereto) corresponding to the second edge  30  and at least one second triggering switch  60  (one shown in  FIG. 2 , but not limited thereto) corresponding to the fourth edge  36 . In practical application, for making the cap  14  capable of triggering the first triggering switch  58  and the second triggering switch  60  surely, the second edge  30  could have at least one first bending structure  62  (one shown in  FIG. 4 , but not limited thereto), and the fourth edge  36  could have at least one second bending structure  64  (one shown in  FIG. 4 , but not limited thereto). The first bending structure  62  has a first protruding portion  63  corresponding to the first triggering switch  58 , and the second bending structure  64  has a second protruding portion  65  corresponding to the second triggering switch  60 . In such a manner, when the cap  14  moves to the pressed position as shown in  FIG. 3  relative to the base plate  12  via the lifting mechanism  16 , the first protruding portion  63  presses the first triggering switch  58  and the second protruding portion  65  presses the second triggering switch  60  for triggering the membrane circuit board  56  to complete the triggering operation for executing a corresponding input function. 
         [0019]    The support mechanism  20  is located between the first support plate  22  and the second support plate  24 . The support mechanism  20  could have a first support member  66  and a second support member  68 . The first support member  66  is movably connected to the cap  14  and the base plate  12 . The second support member  68  is movably connected to the cap  14  and the base plate  12  and is pivoted to the first support member  66 . To be more specific in this embodiment, the support mechanism  20  could preferably adopt a scissor support design, and the related description could be as shown in  FIG. 1  and  FIG. 5 .  FIG. 5  is an exploded diagram of the base plate  12 , the cap  14 , and the support mechanism  20  in  FIG. 1 , and the base plate  12  and the cap  14  are partially depicted in  FIG. 5 . As shown in  FIG. 1  and  FIG. 5 , the cap  14  could have a first sliding slot  70  and a first engaging slot  72 . The base plate  12  could have a second sliding slot  74  and a second engaging slot  76 . The first support member  66  could have a first sliding portion  78  and a first pivot portion  80 . The first sliding portion  78  is slidably disposed in the first sliding slot  70 , and the first pivot portion  80  is rotatably connected to the second engaging slot  76 . The second support member  68  could have a second sliding portion  82  and a second pivot portion  84 . The second sliding portion  82  is slidably disposed in the second sliding slot  74 , and the second pivot portion  84  is rotatably connected to the first engaging slot  72 . In such a manner, during the cap  14  moves between the non-pressed position and the pressed position as shown in  FIG. 3 , the aforesaid connection design could generate the effect that a edge of the cap  14  close to the terminal point P of the longitudinal axis L could move together with a center portion of the cap  14  close to the center point C via the first support member  66  and the second support member  68 . Furthermore, the aforesaid connection design could also increase the pull-out force of the cap  14  via connection of the first sliding portion  78  and the first sliding slot  70  and connection of the second pivot portion  84  and the first engaging slot  72  to efficiently solve the prior art problem that the cap of the conventional multiple-width keyswitch could fall off easily. 
         [0020]    In practical application, the keyswitch  10  could further adopt an auxiliary support to improve the motion steadiness of the cap  14 . For example, please refer to  FIG. 1  and  FIG. 6 .  FIG. 6  is a partial enlarged exploded diagram of the keyswitch  10  in  FIG. 1 . As shown in  FIG. 1  and  FIG. 6 , the keyswitch  10  could further include at least one auxiliary support  86  (two shown in  FIG. 1 , but not limited thereto). The auxiliary support  86  is disposed between the cap  14  and the base plate  12  and is alternately arranged with the support mechanism  20 . The auxiliary support  86  could have a third engaging structure  88  corresponding to the base plate  12 , and the base plate  12  could have a fourth engaging structure  90  corresponding to the third engaging structure  88 . The third engaging structure  88  is engaged with the fourth engaging structure  90  (e.g. via the structural engagement design of the sliding portion (could be regarded as the third engaging structure  88 ) and the sliding slot (could be regarded as the fourth engaging structure  90 ) as shown in  FIG. 6 , but not limited thereto), to make the auxiliary support  86  movably connected to the base plate  12 . Furthermore, the auxiliary support  86  could have a fifth engaging structure  92  corresponding to the cap  14  and the cap  14  could have a sixth engaging structure  94  corresponding to the fifth engaging structure  92 . The fifth engaging structure  92  is engaged with the sixth engaging structure  94  (e.g. via the structural engagement design of the pivot portion (could be regarded as the fifth engaging structure  92 ) and the engaging slot (could be regarded as the sixth engaging structure  94 ) as shown in  FIG. 6 , but not limited thereto), to make the auxiliary support  86  movably connected to the cap  14 . 
         [0021]    It should be mentioned that the cap returning design adopted by the present invention is not limited to the aforesaid embodiment, meaning that the present invention could utilize a resilient member (e.g. rubber dome or spring) to provide the returning force in another embodiment. For example, please refer to  FIG. 7  and  FIG. 8 .  FIG. 7  is a diagram of a keyswitch  10 ′ according to another embodiment of the present invention.  FIG. 8  is a cross-sectional diagram of the keyswitch  10 ′ in  FIG. 7  along a cross-sectional line B-B when the cap  14  is pressed. For clearly showing the internal mechanical design of the keyswitch  10 ′, the cap  14  is briefly depicted by dotted lines in  FIG. 7 . Components both mentioned in this embodiment and the aforesaid embodiment represent components with similar structures or functions, and the related description is omitted herein. As shown in  FIG. 7  and  FIG. 8 , the keyswitch  10 ′ includes a returning device  18 ′, the base plate  12 , the cap  14 , the lifting mechanism  16 , at least one support mechanism  20  (two shown in  FIG. 7 , but not limited thereto), and a membrane circuit board  56 . In this embodiment, the returning device  18 ′ could include a resilient body  96 . The resilient body  96  could abut against the cap  14  and the base plate  12  respectively. Accordingly, when the external force is released, the compressed resilient body  96  pressed by the cap  14  (as shown in  FIG. 8 ) could provide the returning force to the cap  14 , to make the cap move from a pressed position as shown in  FIG. 8  back to a non-pressed position as shown in  FIG. 7  with the lifting mechanism  16 , for generating the automatic cap returning effect. 
         [0022]    Furthermore, please refer to  FIG. 9 , which is an assembly diagram of a cap  14 ′, the first support plate  22  and the second support plate  24  according to another embodiment of the present invention. Components both mentioned in this embodiment and the aforesaid embodiment represent components with similar structures or functions, and the related description is omitted herein. As shown in  FIG. 9 , at least one first engaging structure  98  (two shown in  FIG. 9 , but not limited thereto) is formed on the cap  14 ′, and the first support plate  22  has a second engaging structure  99  corresponding to the first engaging structure  98 . To be more specific, in this embodiment, the first engaging structure  99  could preferably be a hook extending from the cap  14  toward the first support plate  22 , and the second engaging structure  99  could correspondingly be an engaging hole formed on the first support plate  22 . The first engaging structure  98  (i.e. the hook) is engaged with the second engaging structure  99  (i.e. the engaging hole) to constrain the deformation movement of the cap  14 ′ relative to the first support plate  22 , for preventing the cap  14 ′ from being bulged due to uneven pressing force or stress concentration during the cap  14  is pressed. To be noted, the aforesaid design could also be applied to the second support plate  24  (as shown in  FIG. 9 ), and the related description could be reasoned from analogy. Moreover, the present invention could prevent deformation of the cap via structural engagement of the cap and the base plate in another embodiment. That is to say, in another embodiment, a first engaging structure (e.g. the hook as shown in  FIG. 9 ) could be formed on the cap, and the base plate could have a second engaging structure (e.g. the engaging hole as shown in  FIG. 9 ) corresponding to the first engaging structure. Accordingly, the first engaging structure could be engaged with the second engaging structure for preventing deformation of the cap. As for related description for other derived embodiments (e.g. the first support plate has a hook formed thereon to be engaged with an engaging hole on the cap), it could be reasoned from analogy according to the aforesaid embodiments and omitted herein. 
         [0023]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.