Abstract:
A key device includes: a chassis which has an opening divided by one of a vertical rib and a horizontal rib; a plurality of keys which are arranged along the opening; and a substrate which is housed in the chassis, wherein the rib is engaged with the substrate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2010-091110 filed on 12 Apr. 2010, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a key device miniaturized by clearing one of vertical and horizontal ribs which divide an opening of a chassis into a plurality of spaces for arranging keys, and electronic equipment equipped with the key device. 
     2. Description of Related Art 
     A conventional key device of a desktop calculator or the like has had a configuration in which keytops each having retaining flanges are positioned in an opening of a chassis of the desktop calculator, which opening is divided into a plurality of spaces by vertical and horizontal ribs. However, in order to miniaturize the key device, a configuration in which one of the vertical and horizontal ribs dividing the opening is cleared has been desired. In order to achieve such configuration, it has also been necessary to clear the flanges of each of the keytops. 
     For example, Japanese Patent Application Laid-Open Publication No. 2007-109486 proposes a key switch configuration in which keytops each having no flange are adhered on a base film. 
     Although the keytops disclosed in the above patent document are provided with no flange, adhering such keytops onto the base film becomes necessary. 
     However, there is a problem that adhering the keytops onto the base film requires high costs. 
     Moreover, when clearing one of the vertical and horizontal ribs provided in the chassis for arranging keys, strength reduction of the chassis becomes a problem. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to ensure strength of a chassis while miniaturizing a key device by clearing one of the vertical and horizontal ribs which divide an opening of the chassis into a plurality of spaces for arranging keys. 
     According to a first aspect of the present invention, there is provided a key device including: a chassis which has an opening divided by one of a vertical rib and a horizontal rib; a plurality of keys which are arranged along the opening; and a substrate which is housed in the chassis, wherein the rib is engaged with the substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will sufficiently be understood by the following detailed description and accompanying drawing, but they are provided for illustration only, and not for limiting the scope of the invention: 
         FIG. 1  is a front view of a desktop calculator and shows a configuration of electronic equipment according to an embodiment to which the present invention is applied; 
         FIG. 2  is an enlarged sectional view along arrowed line A-A of  FIG. 1 ; 
         FIG. 3  is an enlarged sectional view along arrowed line B-B of  FIG. 1 ; 
         FIG. 4A  is a partially-broken enlarged perspective view of an upper case in which keys of  FIG. 1  are set, viewed from an under side; 
         FIG. 4B  is an enlarged view of a main part of  FIG. 4A ; 
         FIG. 5  is a partially-broken enlarged perspective view showing an engagement relation between a rib and a substrate; and 
         FIG. 6  is a perspective view of the substrate of  FIG. 5 , viewed from an under side. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the present invention will be described in detail with reference to the drawings. 
       FIG. 1  shows a desktop calculator as a configuration of electronic equipment according to one embodiment to which the present invention is applied. In  FIG. 1 , reference number  1  indicates a chassis, reference number  2  indicates a display section, reference number  3  indicates a key device according to the present invention, and reference number  4  indicates another key device. 
     In the illustrated example, the chassis  1  is equipped with the display section  2  in an upper portion thereof, the key device  3  of the present invention in a lower portion thereof, and the another key device  4  in a middle portion thereof. 
     Each of  FIGS. 2 and 3  shows a cross section of the key device  3  according to the present invention. In each of  FIGS. 2 and 3 , reference number  11  indicates an upper case, reference number  12  indicates a horizontal rib, reference numbers  31  indicate keys, reference number  35  indicates a substrate, and reference number  37  indicates an inner rubber. 
     As illustrated in the drawings, in the lower portion of the upper case  11  of the chassis  1 , only the horizontal ribs  12  which divide an opening into upper parts and lower parts for horizontally arranging the keys  31  of the key device  3  of the present invention are formed, and no vertical rib is formed. 
     Each of the keys  31  is retained so as not to fall off, with flanges  32  abutting against upper and lower portions of the opening of the upper case  11 , which opening is divided into a plurality of spaces by the horizontal rib  12 . Concretely, the flanges  32  abut against backsides of the horizontal ribs  12 , and backsides of parts of the upper case  11 , which parts are at a peripheral portion of the opening. Each of the keys  31  is placed to be stacked on a dome portion of the inner rubber  37  being stacked on the substrate  35 , the dome portion corresponding to a switch portion of the substrate  35 . 
     Each of  FIGS. 4A and 4B  is a view of the upper case  11  viewed from the under side thereof, into which upper case  11  the keys  31  are inserted. As shown in  FIGS. 4A and 4B , positioning guides  13  are formed on back sides of the horizontal ribs  12 . Each of positioning guides  13  abuts against side surfaces of the flanges  32  at upper/lower portions of the keys  31 . Moreover, similar positioning guides  13  are formed at portions of the upper case  11 , which portions are along a vertical direction of the opening in which the keys  31  are arranged. Concretely, the similar positioning guides  13  are formed on backsides of parts of the upper case  11 , which parts are at a peripheral portion of the opening. 
     A boss  14  is formed integrally with each of the positioning guides  13  so as to be stacked on the inner rubber  37  which is stacked on the substrate  35 . Furthermore, a projection  15  which is longer than the boss  14  is formed integrally with each of the positioning guides  13 . In the illustrated example, the bosses  14  and the projections  15  are arranged alternately in a horizontal direction. 
     A backlash in the horizontal direction of the keys  31  is prevented by the abutting states of a right side surface and a left side surface of each of the flanges  32  against the positioning guides  13  of the ribs  12 . 
     A backlash in the vertical direction of the keys  31  is prevented by the abutting state of an upper side surface and a lower side surface of each of the keys  31  against the ribs  12 , and against an upper portion or a lower portion along the opening of the upper case  11 . 
     Each of  FIGS. 5 and 6  shows an engagement relation between each of the ribs  12  and the substrate  35 . As shown in the drawings, a hole  36  into which each of the projections  15  of the ribs  12  is inserted is formed in the substrate  35 . Moreover, a hole  38  through which each of the projections  15  of ribs  12  penetrates is formed in the inner rubber  37 . 
     Thus, each of the projections  15  of the ribs  12  is engaged at two portions in the horizontal direction by penetrating the hole  38  of the inner rubber  37  and being inserted into the hole  36  of the substrate  35 . 
     The substrate  35  is screwed to be fixed on the upper case  11 . Beneath the substrate  35 , a lower case  16  is stacked thereon. The lower case  16  is fixed on the upper case  11  by screwing a periphery of the lower case  16 . 
     As described above, according to the desktop calculator of the embodiment, since the vertical ribs are cleared in the key device  3  in the lower portion of the desktop calculator and the opening is divided only by the horizontal ribs  12  for horizontally arranging the keys  31 , the keys  31  can be arranged so as to be at most close portions to one another in the horizontal direction, and thereby the key device  3  can be miniaturized. 
     Furthermore, since each of the projections  15  of the horizontal ribs  12  is engaged at the two portions by penetrating through the hole  38  of the inner rubber  37  and being inserted in to the hole  36  of the substrate  35 , rigidly of the horizontal ribs  12  can be ensured while clearing the vertical ribs, and thereby a strength of the chassis  1  can be ensured. 
     (Variation) 
     Although the example of the desktop calculator is described in the above embodiment, the present invention is not limited to this, and can be applied to all equipment such as camera, PDA, notebook computer, wearable personal computer, electronic dictionary, and cellular phone. 
     Moreover, though the above embodiment provide the horizontal ribs and clears the vertical ribs, it is also possible to clear the horizontal ribs and provide the vertical ribs. 
     Furthermore, the configuration such as shapes of keys and ribs is arbitrary, and it is a matter of course that other concrete detailed configuration and the like can be changed appropriately.