Abstract:
A mouse is disclosed to include a casing covered with a top cover shell, a first wheel and a second wheel respectively rotatably mounted inside the casing, a caterpillar track surrounded on the first and second wheels and partially exposed to the outside of an opening of the top cover shell for movement by an user comfortably to rotate the first wheel and the second wheels smoothly without causing ache or injury of the operator&#39;s finger.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a mouse for use in a computer system and more particularly, to a computer mouse that has a caterpillar track assembly. 
         [0003]    2. Description of Related Art 
         [0004]    A computer normally is equipped with a mouse. A computer mouse has a wheel for window scrolling. Further, when press the wheel downward, the wheel provides a third mouse button function. However, in a conventional mouse that generates signal either by means of an optical receiver means or an encoder, the wheel is rotatable on the axis passing through its axle center. Therefore, when operating the wheel, the finger that operates the wheel is moved from the bottom side toward the top side or from the top side toward the bottom side. This operation manner is not in conformity with human factor engineering. After long uses, the hand of the user that operates the wheel may ache or be injured. 
         [0005]    In general, the structure of the wheel of a conventional mouse is a design of a single axle center, and the wheel is rotated on the axle center. Further, based on this design, the part of the wheel that is exposed to the outside of the mouse is smoothly arched, i.e., the wheel of the mouse has a circular shape. When rotating the wheel of the mouse, the finger of the user that moves the wheel of the mouse is moved from the bottom side toward the top side and then from the top side toward the bottom side like moving over the peak of a mountain. Therefore, the user&#39;s finger may ache or be injured easily after a long use. Therefore, the conventional mouse is not in conformity with human factor engineering. 
         [0006]    Therefore, it is desirable to provide a mouse that eliminates the aforesaid drawbacks. 
       SUMMARY OF THE INVENTION 
       [0007]    A mouse according to the present invention is comprised of a casing, a first wheel, a second wheel, an encoder, a caterpillar track, and a top cover shell. The casing has an accommodation open chamber. The accommodation open chamber has first pivot means, and second pivot means. 
         [0008]    The first wheel is accommodated in the accommodation open chamber, and pivotally coupled to the first pivot means. The second wheel is accommodated in the accommodation open chamber, and pivotally coupled to the second pivot means. The encoder is axially mounted on and rotatable with one of the first wheel and the second wheel. Further, the caterpillar track is surrounded on the first wheel and the second wheel. The top cover shell is fastened to the casing to close the accommodation open chamber, having an opening corresponding to the caterpillar track for enabling a part of the caterpillar track to expose to the outside of the top cover shell. 
         [0009]    Therefore, the caterpillar track is surrounded on the first wheel and the second wheel, i.e., the caterpillar track is rotatable about two axle centers. Therefore, the caterpillar track provides a substantially flat operation surface for operation by the user, eliminating the drawback of the upwardly protruding operation surface of the prior art design. Further, by means of the aforesaid structural design, the route of movement of the caterpillar track is relatively smoother than the prior art design. This design fits human factor engineering and smoothens the operation. Therefore, the user can operate the mouse comfortably, preventing ache or injury of the hand. 
         [0010]    Further, the casing comprises a carrier mounted inside the accommodation chamber, the first pivot means and the second pivot mans are respectively formed on the carrier. 
         [0011]    Further, the accommodation open chamber of the casing comprises a press button, and the carrier comprises a stop face adapted to press the press button. 
         [0012]    The casing further comprises third pivot means. Further, a third wheel is accommodated in the accommodation open chamber and pivotally coupled to the third pivot means. 
         [0013]    Further, the top cover shell comprises an outer surface. The caterpillar track has a part exposed to the outside of the opening of the top cover shell and kept in flush with the outer surface of the top cover shell. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is an exploded view of a mouse in accordance with a first embodiment of the present invention. 
           [0015]      FIG. 2  is another exploded view of the mouse in accordance with the first embodiment of the present invention. 
           [0016]      FIG. 3  is an exploded view of a mouse in accordance with a second embodiment of the present invention. 
           [0017]      FIG. 4  is an exploded view of a mouse in accordance with a third embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    Referring to  FIG. 1  and  FIG. 2 , a mouse in accordance with a first embodiment of the present invention is shown comprised of a casing  1 , a first wheel  2 , a second wheel  3 , an encoder  4 , a caterpillar track  5 , and a top cover shell  6 . 
         [0019]    The casing  1  defines an accommodation open chamber  13 . First pivot means  11  and second pivot means  12  are provided inside the accommodation open chamber  13 . According to this embodiment, a carrier  14  is provided inside the accommodation open chamber  13  of the casing  1 . The first pivot means  11  and second pivot means  12  are formed on the carrier  14  respectively. 
         [0020]    Further, two pairs of first sliding members  131  are provided at two sides inside the accommodation open chamber  13 , and two pairs of second sliding members  142  are provided at two sides of the carrier  13  corresponding to the first sliding members  131  respectively. According to this embodiment, the first sliding members  131  are vertical sliding grooves  133 , the second sliding members  142  are vertical sliding rails  143 . The vertical sliding rails  143  are respectively coupled to the vertical sliding grooves  133  so that the carrier  14  can be slid vertically up and down in the accommodation open chamber  13  inside the casing  1 . 
         [0021]    Further, a press button  132  is mounted on a circuit board  16  inside the accommodation open chamber  13  below the carrier  14 . The carrier  14  has a stop face  144 . When the carrier  14  is slid downwards by the first sliding members  131  and the second sliding members  142 , the stop face  144  is pressed on the press button  132 , thereby providing the so-called third mouse button function. 
         [0022]    The first wheel  2  is accommodated in the carrier  14  inside the accommodation open chamber  13  of the casing  1  and pivotally coupled to the first pivot means  11 . The second wheel  3  is accommodated in the carrier  14  inside the accommodation open chamber  13  of the casing  1  and pivotally coupled to the second pivot means  12 . 
         [0023]    According to this embodiment, the carrier  14  has a trough  141 . The first wheel  2  is accommodated in the trough  141  of the carrier  14  and pivotally coupled to the first pivot means  11 . The second wheel  3  is accommodated in the trough  141  of the carrier  14  and pivotally coupled to the second pivot means  12 . 
         [0024]    The first pivot means  11  according to this embodiment comprises two pivot holes  111  on the peripheral wall of the carrier  14  at two sides of the trough  141 . The first wheel  2  has a fixed wheel axle  21 , which has two distal ends respectively pivotally coupled to the pivot holes  111  of the first pivot means  11 . The second pivot means  12  according to this embodiment comprises two pivot holes  121  on the peripheral wall of the carrier  14  at two sides of the trough  141 . The second wheel  3  has a fixed wheel axle  31 , which has two distal ends respectively pivotally coupled to the pivot holes  121  of the second pivot means  12 . Therefore, the first wheel  2  and the second wheel  3  can be rotated in the carrier  14 . 
         [0025]    The encoder  4  is axially mounted on the second wheel  3  and rotatable with the second wheel  3  to detect the number of rotations when the second wheel  3  is rotated. Further, the caterpillar track  5  is surrounded on the first wheel  2  and the second wheel  3 . The top cover shell  6  is fastened to the top side of the casing  1  to close the accommodation open chamber  13 , having an opening  61  corresponding to the caterpillar track  5  so that a part of the caterpillar track  5  is exposed to the outside of the top cover shell  6 . 
         [0026]    According to this embodiment, the caterpillar track  5  is made out of rubber. The top cover shell  6  has an outer surface  62 . The caterpillar track  5  is partially exposed to the outside of the opening  61  of the top cover shell  6  and kept in flush with the outer surface  62 , maintaining the sense of beauty. Of course, the caterpillar track  5  can be made having a part exposed to the outside of the opening  61  above the elevation of the outer surface  62  of the top cover shell  6 . 
         [0027]    Further, the caterpillar track  5  has a plurality of ribs  51  over its outer surface. The ribs  51  increase the friction force when the user moves the caterpillar track  5  with the finger. Therefore, the user can move the caterpillar track  5  with the finger positively. 
         [0028]    Therefore, by means of the structural design of the caterpillar track  5  on the first wheel  2  and the second wheel  3 , the caterpillar track  5  is rotatable about two axle centers. Therefore, the caterpillar track  5  provides a substantially flat operation surface for operation by the user. This design eliminates the drawback of the upwardly protruding operation surface of the prior art design. Further, by means of the aforesaid structural design, the route of movement of the caterpillar track  5  is relatively smoother than the prior art design. This design fits human factor engineering, and smoothens the operation, eliminating the problem of the prior art design to move the finger from the bottom side toward the top side or from the top side toward the bottom side. Therefore, the user can operate the mouse comfortably, preventing ache or injury of the hand. 
         [0029]      FIG. 3  shows a mouse in accordance with a second embodiment of the present invention. This embodiment is substantially similar to the aforesaid first embodiment of the present invention with the exception that the increased spread of axles between the first wheel  82  and the second wheel  83  inside the casing  81  and the increased length of the opening  841  of the top cover shell  84 . Because of the increased spread of axles between the first wheel  82  and the second wheel  83  and the increased length of the opening  841  of the top cover shell  84 , the operation surface area of the caterpillar track  85  is relatively increased and, the user can move the caterpillar track  85  with the finger more conveniently to achieve the same effect as the aforesaid first embodiment of the present invention. 
         [0030]      FIG. 4  shows a mouse in accordance with a third embodiment of the present invention. This embodiment is substantially similar to the aforesaid first embodiment of the present invention with the exception that the additional third wheel  7 , which is mounted in the accommodation open chamber  130  of the casing  10  and pivotally coupled to third pivot means  15  in the casing  10  to support the caterpillar track  71 . Because of the use of the additional third wheel  7 , the length of (the major axis) of the caterpillar track  71  is relatively greater than the aforesaid first embodiment of the present invention. Further, the length of the opening  601  of the top cover shell  60  according to this third embodiment is relatively increased. This embodiment achieves the same various effects of the aforesaid second embodiment. If desired, four, five or more wheels may be used to support the caterpillar track. 
         [0031]    Although the present invention has been explained in relation to its preferred embodiments, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.