Abstract:
A Z-axis device for an input device has a rotatable roller having a first side and a second side, the second side of the roller having a plurality of grooves. The Z-axis device also has a support mechanism that positions the roller for reciprocating pivoting movement, a first axle extending from the first side of the roller and supported by the support mechanism, and a second axle extending from the second side of the roller and supported by the support mechanism. The second axle has a resilient element coupled thereto, with the resilient element constantly engaging one of the grooves, and engaging different grooves as the roller is rotated.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to input devices, and in particular, to a ratchet structure for use in an input device such as a computer mouse.  
           [0003]    2. Description of the Prior Art  
           [0004]    The increased popularity of personal computers (PCs) also means that the accompanying input devices, such as computer mice, are widely used as well. Many computer mice are provided with a roller thereon for controlling the movement of a Z-axle on the display. This Z-axis control mechanism is often used for scrolling a screen and is especially useful in Internet applications. Examples include U.S. Pat. No. 6,198,057 for a rotary operating-type electronic device, U.S. Pat. No. 6,157,369 for an optical-mechanical roller with ratchet, U.S. Pat. No. 6,326,949 for a wheel support guide for vertical wheel support movement, and U.S. Pat. No. 5,912,611 for a Z-encoder mechanism.  
           [0005]    The above-mentioned patents disclose complicated Z-axis devices positioned at the base of the input device for supporting a wheel or roller support mechanism. The roller can be pressed to activate a micro switch for controlling certain operations. Some of these Z-axis devices also provide a corresponding ratchet mechanism that provides a ratchet feedback effect while the roller is being turned by a user. The turning of the roller with a ratchet mechanism also allows for precise positioning at the desired location.  
           [0006]    Although the above-mentioned patents describe Z-axis devices that can achieve the effect of precise control when turning the roller, a number of drawbacks still remain. For example, the Z-axis devices in U.S. Pat. Nos. 6,157,369 and 6,326,949 occupy smaller operating spaces, but each involves a complex structure that carries with it a higher cost to produce. The large variety of the components in each of these structures will result in a higher molding cost, and will also make them hard to assemble, especially when the manufacturing will require an increased number of operating procedures with small tolerances for error.  
           [0007]    As another example, U.S. Pat. No. 5,912,611 discloses a Z-axis device that has a simple structure but the structure occupies a larger space, which goes against the modern trend of minimizing the sizes of all electronic products.  
           [0008]    Thus, there still remains a need for a Z-axis device that has a simple structure which occupies minimal space and which is inexpensive to manufacture.  
         SUMMARY OF THE DISCLOSURE  
         [0009]    It is an object of the present invention to provide a Z-axis device for an input device that has a simple construction.  
           [0010]    It is another object of the present invention to provide a Z-axis device for an input device that occupies minimal space in the input device.  
           [0011]    It is yet another object of the present invention to provide a Z-axis device for an input device that is inexpensive to manufacture.  
           [0012]    In order to accomplish the objects of the present invention, the present invention provides a Z-axis device for an input device. The Z-axis device has a rotatable roller having a first side and a second side, the second side of the roller having a plurality of grooves. The Z-axis device also has a support mechanism that positions the roller for reciprocating pivoting movement, a first axle extending from the first side of the roller and supported by the support mechanism, and a second axle extending from the second side of the roller and supported by the support mechanism. The second axle has a resilient element coupled thereto, with the resilient element constantly engaging one of the grooves, and engaging different grooves as the roller is rotated. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a perspective view of a Z-axis device within an input device according to one embodiment of the present invention.  
         [0014]    [0014]FIG. 2 is an exploded perspective view of the ratchet structure for the Z-axis device of FIG. 1.  
         [0015]    [0015]FIG. 3 is a cross-sectional view of the Z-axis device of FIG. 1.  
         [0016]    [0016]FIG. 4 is a perspective view of a Z-axis device within an input device according to another embodiment of the present invention.  
         [0017]    [0017]FIG. 5 is an exploded perspective view of the ratchet structure for the Z-axis device of FIG. 4.  
         [0018]    [0018]FIG. 6 is a cross-sectional view of the Z-axis device of FIG. 4.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims.  
         [0020]    FIGS.  1 - 3  illustrate one embodiment of a Z-axis device according to the present invention. The Z-axis device of the present invention is used in connection with an input device, such as a computer mouse. FIG. 1 illustrates a base  10  of an input device, such as a computer mouse, with a roller  20  provided on the base  10 . A pair of supports  12   a  and  12   b  are fixed on the base  10 . A micro-switch  14  is positioned on the printed circuit board (PCB)  15  on an external side of one of the supports  12   a . The roller  20  is positioned between the supports  12   a ,  12   b . The roller  20  is supported on the support  12   a  by an axle sheath  30 , and on the other support  12   b  by an outer axle  24 . The outer axle  24  extends from a first side of the rim  22  of the roller  20 . The outer axle  24  has a grating  240  that defines a plurality of alternating cut-outs. The roller  20  has an inner axle  26  extending from a second side of the rim  22  of the roller  20 . The roller  20  has grooves  28  provided around the inner periphery of the roller  20  on the second side of the rim  22 . The inner axle  26  is inserted into an internal bore  33  of the axle sheath  30  to couple the axle sheath  30  to the roller  20 . The axle sheath  30  is seated in a U-shaped groove  121  provided at the top of the support  12   a  adjacent to the micro switch  14 , and is adapted to experience upward and downward pivoting movement within the groove  121  when the user presses on or releases the roller  20 . The axle sheath  30  also has a protrusion  32  extending from its bottom that is adapted to activate the micro switch  14  when the protrusion  32  contacts the micro switch  14 .  
         [0021]    A base member  35  supports the axle sheath  30  and a resilient element  34  that is spaced apart from the axle sheath  30  and which extends generally parallel to the axle sheath  30 . The resilient element  34  can be a flexible shaft that extends from the base member  35 , and has an enlarged tip  39  that is adapted to constantly engage (i.e., be seated within) one of the grooves  28  such that the rotation of the roller  20  provides a ratchet tactile feedback to a user. The resilient element  34 , the base member  35 , and the axle sheath  30  can be provided together in one piece.  
         [0022]    As shown in FIG. 3, the sheath  30  is sleeved onto the inner axle  26  and the roller  20  is positioned between the supports  12   a ,  12   b , with the outer axle  24  pivoted on an upper groove in the support  12   b  and the axle sheath  30  pivoted on the support  12   a  inside the groove  121 . A fixing element  31  extends from the bottom of the axle sheath  30  and lies in the groove  121 . The fixing element  31  has a configuration (e.g., a square, rectangular or other configuration that has straight sides that will resist rotation) which functions to prevent the axle sheath  30  from rolling or rotating when the user rotates the roller  20 . An emitter  16  and a receiver  18  are positioned on opposite sides of the grating  240 . For example, the emitter  16  can be positioned on the PCB  15  between the supports  12   a ,  12   b , and the receiver  18  can be positioned on the PCB  15  on the external-facing side of the support  12   b . The emitter  16  emits light that is directed at the receiver  18 , with the rotation of the roller  20  (and the grating  240 ) causing the light to be intermittently received by the receiver  18  via the alternating cut-outs of the grating  240 . The emitter  16  and the receiver  18  form an encoding device that is well-known in the art, so that further discussion of the emitter  16 , the receiver  18 , and their operation, will not be necessary.  
         [0023]    When a user is using the Z-axis device shown in FIGS.  1 - 3 , the user will turn the roller  20  to scroll the contents on a display (such as a monitor connected to a computer). Since each of the slots of the grating  240  corresponds to one of the grooves  28  for purposes of outputting a position signal to the processor (not shown, but typically provided on the PCB  15 ) of the input device, the actual scrolling can be controlled to a great degree of accuracy. If the user presses the roller  20 , the protrusion  32  of the axle sheath  30  will move downward to contact, and therefore activate, the micro switch  14 , facilitating a further predetermined function, such as fast scrolling, log-on the Internet, etc.  
         [0024]    FIGS.  4 - 6  illustrate another embodiment of a Z-axis device according to the present invention. The PCB  15 , the axle sheath  30 , the resilient element  34 , the supports  12   a ,  12   b , the groove  121 , and the micro switch  14  are all identical to those in FIGS.  1 - 3 , and so the same numerals will be used to designate these elements in FIGS.  1 - 3  and in FIGS.  4 - 6 . In the embodiment of FIGS.  4 - 6 , the roller  40  is slightly different from the roller  20  in FIGS.  1 - 3  in that the rim  42  is now combined with the grating  420 . In other words, the cut-outs of the grating  420  are now provided as cutouts in the rim  42 , so that the grating  420  and the rim  42  are actually the same element. The roller  40  is still supported on the support  12   a  by the axle sheath  30 , and on the other support  12   b  by an outer axle  44 . The outer axle  44  extends from a first side of the rim  42 . The roller  40  has an inner axle  46  extending from a second side of the rim  42 , and is inserted into the internal bore of the axle sheath  30  to couple the axle sheath  30  to the roller  40 .  
         [0025]    As shown in FIG. 6, the sheath  30  is sleeved onto the inner axle  46  and the roller  40  is positioned between the supports  12   a ,  12   b , with the outer axle  44  pivoted on the support  12   b  and the axle sheath  30  pivoted on the support  12   a . A fixing element  31  still extends from the bottom of the axle sheath  30  and lies in the groove  121 , and functions to prevent the axle sheath  30  from rolling or rotating when the user rotates the roller  40 .  
         [0026]    As shown in FIG. 6, the emitter  16   x  and the receiver  18   x  are positioned differently from the emitter  16  and the receiver  18  in FIGS.  1 - 3 . In particular, the emitter  16   x  and the receiver  18   x  are positioned between the pair of supports  12   a ,  12   b , with the emitter  16   x  positioned on one side of the rim  42  (and grating  420 ) and the receiver  18   x  positioned on the other side of the rim  42  (and grating  420 ) so that the light from the emitter  16   x  can pass through the cut-outs in the grating  420  to be received intermittently by the receiver  18   x . Positioning the emitter  16   x  and the receiver  18   x  between the pair of supports  12   a ,  12   b  further minimizes the space occupied by the Z-axis device within the input device.  
         [0027]    Thus, the compact design of the axle sheath  30  and the roller  20  or  40  minimizes the space requirements for the Z-axis device of the present invention. The construction of the axle sheath  30  and the rollers  20  and  40  are also simple, thereby allowing the manufacturer to minimize the cost of making the input device.  
         [0028]    While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.