Abstract:
The invention discloses a key structure comprising a keycap, a base plate, and a support member. The keycap comprises a slide part; the base plate comprises an engagement part; the support member comprises a slide end and an engagement end, and the support member is used for engaging the keycap and the base plate. The slide end slides along the slide part, and the engagement end is engaged to the engagement part. Therein, the slide end comprises a connection part, and the connection part comprises at least one concave part or at least one hole.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 097200678 filed in Taiwan R.O.C. on Jan. 11, 2008, the entire contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a key structure, and more particularly relates to a key structure with a larger deformation limit. 
   2. Description of the Prior Art 
   In more developed countries, especially those which are information-rich, almost every family has at least one computer. Computers are used to help people get information from the Internet, or communicate with others by means of messenger software. The most common input device of a computer is a keyboard. The elementary component of a keyboard is a key. Please refer to  FIG. 1 .  FIG. 1  is a cross-sectional view of a key structure  1  in the prior art. As illustrated in  FIG. 1 , the key structure  1  includes a key a keycap  10 , a support member  12  and a base plate  14 . The keycap  10  can move perpendicularly relative to the base plate  14  by means of the support member  12 . When the keycap  10  needs to be separated from the support member  12 , owing to the keycap  10  is commonly engaged with the support member  12  by a tenon, the support member  12  is easily damaged if the removing force or the direction of removing the keycap  10  is inappropriate. 
   Accordingly, the main aspect of the present invention is to provide a key structure with a larger deformation limit to solve the problems mentioned above. 
   SUMMARY OF THE INVENTION 
   An aspect of the present invention is to provide a key structure with a concave part to increase the deformation limit and the flexibility. 
   According to a preferred embodiment, the key structure of the invention comprises a keycap, a base plate, and a support member. The keycap comprises a first engagement part and a first slide part; the base plate comprises a second engagement part and a second slide part; and the support member engages with the keycap and the base plate, the support member comprises a first brace and a second brace. The first brace crisscrosses and engages with the second brace, the first brace comprises a first end and a second end, the second brace comprises a third end and a fourth end. The first end engages with the first engagement part, and the second end slides along the second slide part. The third end slides along the first slide part, and the fourth end engages with the second engagement part. Wherein the third end comprises a connection part, and the connection part comprises at least one concave part or at least one hole. 
   Thereby, the concave part of the connection part increases the deformation limit of the connection part. When the keycap needs to be detached from the support member, alternatively, the third end of the second brace sustains a detaching force, and the connection part of the third end can sustain a larger deformation. The connection part will not be damaged while the keycap is detached from the support member. Thus, the durability of the key structure can be increased. 
   The objective 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, which is illustrated in the various figures and drawings. 

   
     BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
       FIG. 1  is a cross-sectional view of a key structure according to the prior art. 
       FIG. 2  illustrates a key structure according to the first embodiment of the present invention. 
       FIG. 3A  illustrates a third end of a support member in  FIG. 2 . 
       FIG. 3B  illustrates a third end according to a second embodiment. 
       FIG. 3C  illustrates a third end according to a third embodiment. 
       FIG. 4  illustrates a second brace according to a fourth embodiment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Please refer to  FIG. 2 .  FIG. 2  illustrates a key structure  2  according to the first embodiment of the present invention. The key structure  2  comprises a keycap  20 , a support member  22 , and a base plate  24 . The keycap  20  comprises a first engagement part  200  and a first slide part  202 . The base plate  24  comprises a second engagement part  240  and a second slide part  242 . 
   In the first embodiment, the support member  22  engages with the keycap  20  and the base plate  24 , and the keycap  20  can move perpendicularly to the base plate  24  by means of the support  22 . The support member  22  comprises a first brace  220  and a second brace  222 . The first brace  220  crisscross engages with the second brace  222 . As illustrated in  FIG. 2 , the first brace  220  and the second brace  222  are shaped approximately as a square frame. There are two protrusion pillars protruding at about the middle of the outside rim of the first brace  220 , and there are two concaves formed at about the middle of the inside rim of the second brace  222 . The two concaves correspondingly engage with the two protrusion pillars, so the first brace  220  crisscrosses and engages with the second brace  222 . Thus, the first brace  220  and the second brace  222  are shaped like a pair of scissors that enables the keycap  20  to move perpendicularly relative to the base plate  24 . 
   The first brace  220  comprises a first end  2200  and a second end  2202 , the second brace  222  comprises a third end  2220  and a fourth end  2222 . The first engagement part  200  is a U-shaped object, and the first end  2200  of the first brace  220  has a pivot. By means of the U-shaped first engagement part  200  clipping the pivot, the first end  2200  engages with the first engagement part  200 . The second slide part  242  is a horizontal U-shaped object and has an L-shaped board extending from a surface of the base plate  24 , and a slide space is formed between the L-shaped board and the surface. The second end  2202  has a slide chunk sliding in the slide space mentioned above. Thereby, the second end  2202  slides along the second slide part  242 . 
   Similar to the engagement between the first end  2200  and the first engagement part  200 , a hook extends from the base plate  24  as illustrated in  FIG. 2 , and the fourth end  2222  has a through hole and a pivot (located under the hook and is not shown in the  FIG. 2 ). The structure of the hook matches the pivot, and a second engagement part  240  is constituted by the surface of the base plate  24  and the hook. Thereby, the hook penetrates the through hole and hooks the pivot, to accomplish the engagement between the second engagement part  240  and the fourth end  2222 , thus the second brace  222  can rotate relative to the pivot. 
   Similar to the engagement between the second end  2202  and the second slide part  242 , the first slide part  202  is also a horizontal U-shaped object and has an L-shaped board extending from a bottom surface of the keycap  20 , and a slide space is formed between the L-shaped board and the bottom surface. The third end  2220  of the second brace  222  correspondingly has two protrusion parts  22200  respectively sliding in the slide spaces of the first slide part  202 . Thereby, the third end  2220  slides along the first slide part  202 . Moreover, the structural variations of the third end  2220  are described in the followings. 
   Please refer to  FIG. 2  and  FIG. 3A .  FIG. 3A  illustrates the third end  2220  of the support member  22  in  FIG. 2 . As illustrated in  FIG. 3A , the third end  2220  comprises two protrusion parts  22200  and a connection part  22202 . The two protrusion parts  22200  protrude from two sides of the connection part  22202 , and the connection part  22202  has a concave part  22204 . The concave part  22204  thereon defines an opening direction OD, when the second brace  220  substantially lies on the base plate  24 , the opening direction OD points to the keycap  20 . Besides, the opening direction OD in another embodiment of the invention could point to the base plate  24 . 
   If users want to remove the keycap  20  from the key structure  2 , they can exert a force on one of the protrusion parts  22200  of the third end  2220 , and the exterior force direction is shown as the curve with an arrow illustrated in  FIG. 3A . Since the connection part  22202  has the concave part  22204  and is thinner, the connection part  22202  could be more flexible. Moreover, the concave space surrounded by the concave part  22204  can be the deformation space of the connection part  22202 , so the concave part  22204  increases the deformation limit of the connection part  22202 . Therefore, when the third end  2220  sustains an exterior force, the connection part  22202  or the protrusion parts  22200  is more difficultly damaged compared to that in the prior art. 
   Please refer to  FIG. 3B .  FIG. 3B  illustrates a third end  3220  according to a second embodiment. As illustrated in  FIG. 3B , the connection part  32202  has three concave parts  32204  between two protrusion parts  32200 . The opening directions of the concave parts  32204  could respectively point to the keycap  20  or the base plate  24  (as shown in  FIG. 2 ). Thus, deformation spaces are not only formed on the first surface  32206  of the connection part  32202 , but also formed on the second surface  32208 . If a corner of the third end  3200  sustains an exterior force (the force direction is shown as the curve with the arrow illustrated in  FIG. 3B ), the deformation of the third end  3200  can be compensated by a concave space surrounded by the concave part  32204  on the first surface  32206  or the second surface  32208 . Thereby, the concave part  32204  increases the deformation limit and the flexibility of the connection part  32202 . 
   Please refer to  FIG. 3C .  FIG. 3C  illustrates a third end  4220  according to a third embodiment. As illustrated in  FIG. 3C , the connection part  42202  has three through holes  42204  between two protrusion parts  42200 . The connection part  42202  thereon defines a first direction FD and a second direction SD perpendicular to the first direction FD. The through holes  42204  penetrate the connection part  42202  along the second direction SD. Please refer to  FIG. 2 . When the second brace  222  substantially lies on the base plate  24 , the first direction FD points to the keycap  20 . If a corner of the third end  4220  sustains an exterior force (the force direction is shown as the curve with an arrow illustrated in  FIG. 3C ), the first surface  42206  of the connection part  42202  is in-curved, and the second surface  42208  is ex-curved. The through holes  42204  provide the deformation and bending spaces. Thereby, the through holes  42204  increase the deformation limit of the connection part  4220 . 
   Additionally, as illustrated in  FIG. 3A , the connection part  22202  thereon defines a direction passing through the protrusion parts  22200 ; the concave part  22204  has a cross-section extending along the defined direction and being a U-shape. The cross-section perpendicular to the defined direction consecutively varies along the defined direction. Definitely, the cross-section of the invention is not limited to a U-shape. The cross-section could be an upside-down U-shape (as shown in  FIG. 3B ), a square-shape (as shown in  FIG. 3C ), an O-shape or a V-shape. If the cross-section is a smooth shape such as a U-shape or an O-shape, the stress could be distributed more uniformly over the connection part. 
   Please refer to  FIG. 4 .  FIG. 4  illustrates a second brace  522  according to a fourth embodiment. As illustrated in  FIG. 4 , both concave parts  52204  thereon define opening directions OD. When the second brace  522  substantially lies on the base plate  24  (as shown in  FIG. 2 ), one of the opening directions OD is perpendicular to the base plate  24 , and the other is parallel to the base plate  24 . The different opening directions OD respectively correspond to different force directions. Therefore, the connection part  52202  has a larger deformation limit under different force with different direction. Furthermore, as illustrated in  FIG. 4 , the protrusion parts  52200  of the third end  5220  have leading corners, and the leading corners could help the protrusion parts  52200  of the third end  5220  to be easily detached from the keycap  20  (as shown in  FIG. 2 ). Namely, the keycap  20  can be more easily removed from the key structure  2 . 
   Compared to the prior art, the key structure of the present invention has concave parts or through holes, so the cross-sectional area of the connection part is decreased and deformation limit of the connection part is increased, meanwhile the connection part still maintains its strength. When the keycap needs to be separated from the support member, the third end of the second brace sustains a pulling force. Because the connection part of the third end can have a larger deformation to absorb the pulling force, the protrusion parts on both sides of the connection part are more difficultly damaged, alternatively, the key structure is durable. Furthermore, the concave parts and the through holes are designed for varying the cross-section of the connection part continuously to avoid stress concentration, such that the connection part will not be easily broken. 
   Although the present invention has been illustrated and described with reference to the preferred embodiment thereof, it should be understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.