Abstract:
A computer input device that comfortably supports the hand of the user while the thumb and fingers are associated with buttons, a trackball, and a scrolling wheel carried on the device. The overall configuration of the device and the arrangement of these actuators permit the user to easily and effectively operate all of the functions provided by the actuators while the hand and arm of the user are in a comfortable position. The device includes a housing having an asymmetrical dividing ridge forming a “thumb-side surface,” for placement of the thumb, and a “finger-side surface,” for placement of the remaining four fingers. The finger-side surface includes a ball rotatably mounted in the housing and further includes first and second input buttons disposed to the side of the ball which may be used as “forward” and “back” buttons. The first and second input buttons adjacent to the ball may be replaced by a linearly slidable or pivotally movable actuator. The movable member is preferably of the three-position-type enabling the user to activate the movable member in a forward or a backward direction for transmission of respective signals to the computer. The thumb-side surface includes a horizontally-disposed scrolling wheel and third and fourth buttons on opposite sides of the scrolling wheel that can be used as “primary” and “secondary” buttons. The primary button has a curved bottom portion that serves as a thumb rest, and may be used as such without activating the button as the button is movable laterally towards the fingers.

Description:
TECHNICAL FIELD 
     This invention relates to an ergonomically designed computer input device. More specifically, the invention relates to an ergonomically designed computer input device for supporting the hand of a user and having a user-manipulable movable ball. 
     BACKGROUND OF THE INVENTION 
     Computer input devices for entering commands into a computer are well known and currently available in a variety of configurations. Many such input devices take the form of a mouse or a trackball device. The term “mouse” is commonly used to refer to a computer input mouse design having a tracking system such as a lower mounted ball or an optical tracking system, for determining the relative movement between the mouse and a surface upon which it rests. The term “trackball device” is commonly used to refer to a computer input device having a body and a rotatable ball coupled to the body for direct manual engagement by a user when the trackball device is resting on a supporting surface. Both the mouse and the trackball device can control the cursor on a computer screen. 
     A mouse frequently includes a rotatable ball mounted to the bottom of a housing. When the mouse is moved over a supporting surface, encoders sense the movement of the ball and generate signals indicative of the direction and amount of that movement. The signals are supplied to a computer and used, for example, to control movement of a cursor on the screen of the computer. The cursor on the computer screen would then be moved in a direction and by an amount corresponding to the movement of the ball. In another arrangement for the mouse, an optical tracking system is used in lieu of the mechanical ball tracking system to measure movement of the mouse with respect to the supporting surface. 
     A trackball-type input device, on the other hand, has its rotatable ball exposed for manipulation by the user&#39;s finger(s) and/or thumb. Ball-movement signals are generated, similar to those described with a mouse, and a cursor on the computer screen is moved in a direction and by an amount corresponding to the movement of the ball. The rotatable ball may be sensed by any conventional mechanical or optical sensing system or any other desired technique. For example, if a mechanical sensing system is used, the ball may be supported on a pair of perpendicular rollers. If an optical sensing system is used, a light source may be reflected off of a portion of the ball, and an optical sensor may determine the relative movement of the ball. 
     Computer input devices, including the mouse and the trackball device, may also include one or more buttons and/or a wheel. Typically, depressing one of the buttons changes the state of an associated switch, which permits a user to enter various commands into the computer. The nature of the command usually depends upon the position of the cursor on the screen. A roller or wheel typically protrudes from the top of the device and is coupled to an encoder for producing a signal indicating the rotation of the wheel. That signal may be used, for example, for scrolling through a window displayed on the computer, which function was heretofore performed by moving the cursor to the window “scroll bar” and depressing a button as needed to scroll through whatever is displayed in the window. For convenience, the wheel will hereafter be referred to as a “scrolling wheel.” The buttons, trackball, and scrolling wheel may be collectively referred to as the actuators carried on the input device. 
     Irrespective of the type of input device employed, mouse or trackball, it is advantageous that the device be comfortable for the user to operate, especially over long periods of time. Such comfort is obtained by careful attention to ergonomic factors, particularly toward minimizing stress in the user&#39;s fingers, wrist, and forearm. Providing a comfortable computer input device can be especially challenging when one&#39;s design goal includes enhancing the function of the device over prior devices. Particularly, prior art finger-controlled trackball devices include drawbacks relating to comfort and/or functionality preventing optimal usability. For example, existing trackball devices do not adequately support the user&#39;s thumb without restricting its motion. Accordingly, an improved ergonomic computer input device was thus needed that overcomes drawbacks of existing designs. More specifically, an improved ergonomic finger-controlled trackball device that maximizes comfort and functionality was thus needed. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, the present invention provides an improved computer input device that eliminates the drawbacks of the prior art. 
     The present invention also provides a computer input device that effectively supports the hand enabling comfortable and efficient activation of various actuators positioned on the housing by the user. 
     The present invention provides an ergonomic finger-controlled trackball device. The device includes a housing having an asymmetrical dividing ridge forming a thumb-side, for placement of the thumb, and a finger-side, for placement of the remaining four fingers. The finger-side surface includes a ball rotatively mounted in the housing and further includes first and second input buttons disposed on the side of the ball which may be used as “forward” and “back” buttons. The thumb-side surface includes a horizontally-disposed scrolling wheel and third and fourth buttons on opposite sides of the scrolling wheel that can be used as “primary” and “secondary” buttons. 
     According to one aspect, the invention includes a computer input device having a housing and an actuator. The housing includes a thumb side adapted for interfacing with a thumb of a hand of a user and a finger side adapted for interfacing with a plurality of fingers of the hand of the user. The actuator includes a wheel positioned on the thumb side enabling its manipulation by the thumb of the user. 
     According to one aspect, the invention includes a computer input device having a housing and an actuator. The housing includes a bottom supporting surface adapted to interface with a planar work surface. The actuator includes a wheel mounted for movement in a plane substantially parallel to the work surface. 
     According to another aspect, the finger-side of the housing has a ball actuator and the thumb-side of the housing has a horizontally-disposed rotatable wheel that is rotatable by moving the thumb with a forward and back motion. Further, there are input buttons on opposite sides of the thumb wheel spanning from the top to the bottom of the thumb-side surface. This interrelationship enables the scrolling wheel to act as a locating divider between the two input buttons. 
     According to one aspect of the present invention, a method of providing input signals to a computer includes the steps of placing a thumb against a wheel rotatively mounted to a computer input device, and moving the thumb to rotate the wheel. 
     In yet another aspect of the invention, a computer input device has a housing and an actuator. The actuator includes a linearly slidable member coupled to the housing and being disposed for engagement by a user. Activation of this actuator causes the input device to send a signal to a computer to produce a command. 
     Another facet of the invention includes a computer input device having a housing, a first actuator, and a second actuator. The housing includes a thumb side adapted for interfacing with a thumb of the hand of a user and a finger side adapted for interfacing with a plurality of fingers of the hand of the user. The first actuator has a pivotally movable member coupled to the housing to be engaged by a user, and adapted to send a signal to a computer when activated. The second actuator includes a sphere for finger engagement mounted to the housing for rotational movement. 
     In another aspect of the invention, a computer input device has a housing and an actuator. The housing has a thumb side adapted for interfacing with a thumb of the hand of the user and a finger side adapted for interfacing with a plurality of fingers of the hand of the user. The actuator includes an input button mounted to the thumb side of the housing. The input button of the actuator has a supporting surface adapted to serve as a thumb rest for the user. Further, the input button is laterally depressible in a direction toward the finger side of the housing for activation. Additionally, a downward force on the supporting surface of the input button will not activate the actuator. 
     Another facet of the invention includes a curved thumb-supporting input button for a computer input device. This button may be located below a scroll wheel on the thumb-side surface of the device. Preferably, the button is curved near its bottom edge to support and cradle the thumb, and provide an effective resting area for the thumb. 
     The foregoing and other features and advantages of the preferred embodiments of the present invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front-radial perspective view of the computer input device schematically coupled to a computer; 
     FIG. 2 is a rear-ulnar perspective view of the computer input device of FIG. 1; 
     FIG. 3 is a top plan view of the computer input device of FIG. 1; 
     FIG. 4 is a radial side elevational view of the computer input device of FIG. 1; 
     FIG. 5 is a front elevational view of the computer input device of FIG. 1; 
     FIG. 6 is a rear elevational view of the computer input device of FIG. 1; 
     FIG. 7 is an ulnar side elevational view of the computer input device of FIG. 1; 
     FIG. 8 is a top plan view skeletal diagram of the right hand of a user with the outer edges of the finger and hand superimposed thereon; 
     FIG. 9 is a view similar to FIG. 4 showing the relationship between the hand of the user and the computer input device; 
     FIG. 10 is a view similar to FIG. 5 showing the relationship between the hand of the user and the computer input device when the user is controlling the ball with one finger; 
     FIG. 11 is a view similar to FIG. 10 showing the relationship between the hand of the user and the computer input device when the user is controlling the ball with two fingers; 
     FIG. 12 is a view similar to FIG. 7 showing the relationship between the hand of the user and the computer input device; 
     FIG. 13 is a cross sectional view taken through line  13 — 13  of FIG. 3 illustrating the relationship between the thumb of the user and computer input device; 
     FIG. 14 is a view similar to FIG. 7 showing an alternative embodiment of the computer input device having a finger-engagable sliding input element; 
     FIG. 15 is a view similar to FIG. 16 showing finger-engagable sliding input element in a different orientation; 
     FIG. 16 is a view similar to FIG. 7 showing an alternative embodiment of the computer input device having a finger-engagable pivoting input element; and 
     FIG. 17 is a view similar to FIG. 16 showing finger-engagable pivoting input element in a different orientation. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1-7 and  9 - 17  depict an ergonomic computer input device  20  configured in accordance with a preferred embodiment of the present invention. The device  20  includes a body or housing  22  having a base or flattened bottom  23  for resting on a planar work surface, such as a desktop  25 . The housing  22  is preferably comprised of a plurality of pieces to facilitate the assembly process. The housing  22  is preferably made from a rigid plastic or other suitable material. The input device  20  has a plurality of actuators carried by the housing  22  enabling a user to provide desired signals to a computer. 
     In a preferred embodiment as shown in FIGS. 1-7, six independently-operable actuators are carried by the housing  22 . The actuators preferably include a plurality of buttons or buttons  28 ,  30 ,  37  and  39 , a trackball  32 , and a wheel  34 . It is recognized that through various known arrangements, such as a software driver, each of the buttons  28 ,  30 ,  37  and  39  can be mapped and/or remapped to provide a signal resulting in any desired command acceptable for various software applications. Additionally or alternatively, if desired, a processor or other intelligent device may be included inside of the housing  22 . However, for reference purposes, the buttons  28 ,  30 ,  37  and  39  are referred to in the specification by a preferred input that they may provide. For example, button  28  provides a signal that is “primary” for most software programs and is herein referred to as the primary button  28 . Button  30  provides a signal that is “secondary” for most software programs and is herein referred to as the secondary button  30 . Buttons  37  and  39  preferably provide signals that respectively correspond to “back” and “forward” commands on an internet browser program. These buttons  37  and  39  are herein referred to as the back button  37  and the forward button  39 . 
     Each of the buttons  28 ,  30 ,  37 , and  39  may be depressed. A switching function is carried out by depressing each button, like the function performed by a conventional mouse when one depresses or “clicks” a button. Specifically, depressing any of the buttons  28 ,  30 ,  37 , and  39  changes the associated switch state and generates a signal that is conveyed via conductors in a cord  36  to a computer  40 . One end of the cord  36  is anchored inside of the device housing  22 . The cord emanates from the front or distal end  38  of the device  20 , and the other end of the cord is coupled with the computer  40 . However, it is recognized that a cord  36  is not needed and the device  20  may be wirelessly coupled to computer  40  by any known arrangement, such as by transmitting and receiving infrared, radio frequency, or ultrasonic signals. 
     The computer  40  may be any one of many different designs. As one example of the many possible configurations and arrangements of devices that the input device  20  may transmit signals to, the computer  40  preferably includes a visual display device  42 . The display  42 , which may be a cathode ray tube-type, active matrix display, or other suitable device, can display a cursor or pointer  44 , along with text and other graphic information. The computer may also include storage or memory  46 , a processor  48 , and a keyboard  50 . 
     The tracking ball  32  is a sphere and preferably mounted in a concave region of the housing  22  for rotation about any axis. The tracking ball  32  includes an exposed surface when it is resting on a supporting surface  25  permitting it to be directly manipulated by a user. To operate the tracking ball  32 , the housing  22  remains stationary and the ball  32  is moved relative to the housing  22  by the user. Optical and/or mechanical sensors detect the movement of the ball  32  in a conventional manner. The sensed movement of the ball  32  is processed and a signal correlating to the rotation of the ball  32  is conveyed via cord  36  or wirelessly to the computer  40 . The received signals may be employed, for example, for moving the pointer  44  across the display  42 . 
     The wheel  34  may be of any desired type. For example, the wheel  34  may be supported on an axle that resides within the body  22  of the input device. That axle may be carried by spaced-apart axle supports. Optical and/or mechanical sensors detect the movement of the wheel  34  in a conventional manner. For example, an optical encoder may be positioned on the axle for rotation with the wheel. A light source and a light sensor may be mounted within the device to sense the motion of the optical encoder. The sensed movement of the wheel  34  is processed and a signal correlating to the rotation of the wheel  34  is conveyed via cord  36  or wirelessly to the computer  40 . The received signals may be employed, for example, for scrolling an image on the display  42 . 
     If desired, the axle supports can be configured to allow one or both ends of the axle to move in a direction that is generally perpendicular to the axis of rotation of the wheel. Thus, the wheel may be depressed, slightly moving its axle to activate a switch. A spring is contained within the housing and arranged to resist depression of the wheel and bias the wheel  34  into an outward position. The switch that is engaged as a result of depression of the wheel provides a switching signal. A detent mechanism may also be provided on the axle to provide a segmented feel to the rotation of the wheel  34 . The wheel switch signal is conveyed via the cord  36  or wirelessly to the computer for any desired purpose. 
     Before proceeding with additional characteristics of the input device  20 , certain concepts and terminology relating to the human hand are herein described. This is accomplished in part by reference to FIG.  8 . As shown in FIG. 8, the hand  105  has a wrist area  107 . There are five major hand bones radiating from the wrist area  107 , which are known as the metacarpals  60 . The finger bones number fourteen in each hand and are designated phalanges  62 . While the depicted embodiment represents a right-hand input device, a mirror image version may be provided for use by a user&#39;s left hand. Accordingly, a right hand is depicted in FIG.  8  and also in FIGS. 9-13. In this description, the particular fingers will carry conventional designations: from left to right in FIG. 8, the thumb  108 , the index finger  106 , the middle finger  111 , the ring finger  120 , and the little finger  124 . 
     Where the index, middle, ring, and little finger  106 ,  111 ,  120 , and  124  meet the palm or, more precisely, where the metacarpal bones  60  and phalangeal bones  62  of the fingers join, there are metacarpal-phalangeal joints  66 ,  68 ,  70 ,  72 . A metacarpal-phalangeal ridge  64  is defined by the portion of the hand in the vicinity of these four joints. Thus, the metacarpal-phalangeal ridge  64  includes the metacarpal-phalangeal joints of all of the fingers except for the thumb. The housing  22  of input device  20  is configured to support the metacarpal-phalangeal joint ridge  64  and the remainder of the hand  105 , so that the user&#39;s hand and arm remain comfortable, and the user&#39;s fingers may comfortably manipulate the actuators. 
     As seen in FIGS. 1-7, the housing  22  includes an upper hand supporting surface  81  that is preferably sized to support the entire hand  105  when the input device  20  is in use. For clarity purposes, it is noted that certain portions of the input device  20  and views are described in conjunction with corresponding portions of the human hand  105 . For example, the side of the input device  20  where the thumb  108  lies when in use is referred to herein as the radial or thumb side  71 . Similarly, the side of the input device  20  where the remaining four fingers  106 ,  111 ,  120 ,  124  lie when in use is referred to herein as the ulnar or finger side  73 . 
     The upper hand supporting surface  81  includes a palm supporting surface  86  at its rear or proximal end  82  that is adapted to support the palm  109  of the user, a radial or thumb supporting surface  84  that is adapted to support the thumb of the user when the input device  20  is in use, and an ulnar or finger supporting surface  96  that is adapted to support the remaining four fingers  106 ,  111 ,  120 ,  124  of the user when the input device  20  is in use. The ulnar or finger supporting surface  96  also supports the metacarpal-phalangeal joint ridge  64 . 
     In a preferred arrangement, the thumb side  71  includes the primary and secondary buttons  28  and  30  and the wheel  34 . The finger side  73  includes the back and forward buttons  37  and  39  and the trackball  32 . This configuration assists in an efficient and comfortable interface that provides a wide number of command options. The finger side  73  and the thumb side  71  are preferably divided by a dividing ridge  95 . As is evident from FIGS. 2 and 3, the dividing ridge  95  is asymmetrical. This places the finger and thumb surfaces  84  and  96  on different planes and enhances the ability of all of the fingers to independently control the actuators. 
     As best shown in FIGS. 1 and 4, the radial or thumb side  71  includes an outer surface  79  containing the primary and secondary buttons  28  and  30  and the wheel  34 . Preferably, both the primary and secondary buttons  28  and  30  are depressible laterally toward the housing. That is, the buttons  28  and  30  are depressible in the direction toward the little finger  124  or the ulnar side of the device  20 . The outer thumb surface  79  preferably extends from an upper edge that helps form the dividing ridge  95  down to a lower edge  85 . The primary and secondary buttons  28  and  30  span substantially the entire distance from the lower edge  85  to the upper edge or dividing ridge  95 . This essentially forms a continuous control panel region whereby the signal that is transmitted depends upon the portion that is depressed. Further, as seen in the figures, the top of the secondary button  30  forms a part of the dividing ridge  95 . 
     The thumb supporting surface  84  is part of the outer thumb side surface  79  and is preferably formed by a cradle-like arrangement  87  adjacent its lower edge  85 . More specifically, the primary button  28  includes the cradle  87 . The outer surface of the primary button  28  has a vertical component  89  and a horizontal component  91 . The cradle  87  includes portions of both the horizontal and vertical components  89  and  91 . The secondary button  30  is generally vertically disposed and is positioned immediately adjacent to the wheel  34  and the primary button  28 . In use, as shown in FIG. 13, the user may place his or her thumb  108  on the cradle  87  and let the full weight of the thumb be carried on the horizontal component  91 . Since the primary button  28  is laterally depressible into the housing  22  in a direction toward the other fingers, a slight shift in weight is all that is needed to activate the primary button  28 . A downward force applied by the thumb  108  to the horizontal component  91  will not activate the primary button  28 . This arrangement effectively provides a thumb rest, reduces fatigue, and facilitates activation. 
     The wheel  34  is located between the primary and secondary buttons  28  and  30  and is also disposed for activation by the user&#39;s thumb  108 . The scrolling wheel  34  is preferably mounted substantially horizontally for rotation in a substantially horizontal plane. Accordingly, the wheel  34  is rotatable in a plane parallel to the desk or work surface  25  upon which the input device  20  sits and parallel to the bottom surface  23  interfacing with the work surface  25 . This horizontal orientation enables the user to move the wheel by natural flexion and extension movements. This will, in turn, reduce possible fatigue. Further, as is evident from FIG. 13, the user can easily engage the wheel  34  for movement with little adjustment as the horizontal portion  91  of the primary button  28  is supporting the thumb  108  immediately adjacent to the wheel  34 . If desired, the wheel  34  may include ribs to provide improved friction between the thumb  108  and the surface of the wheel  34 , which in turn, improve control. Additionally, the scrolling wheel  34 , is in full view of the user on the thumb side which results in providing the user with visual feedback regarding the position of the wheel  34 . 
     As best shown in FIGS. 2,  5 , and  7 , the finger or ulnar side  73  includes the trackball  32  and the forward and back buttons  39  and  37 . The ball  32  is positioned for access and motion by the index finger  106  and/or the middle finger  111 . This placement allows the fingers  106  and/or  111  to rest upon the ball  32  without undue extension or uncomfortable backward or side-to-side bending. Further, the orientation and size of the ball  32  with respect to the finger side supporting surface  96  enables the user to move the ball  32  forward and backward by natural flexion and extension movements and by natural adduction and abduction of the fingers  106  and/or  111 . This will, in turn, reduce possible fatigue and increase control. 
     The back and forward buttons  37  and  39  are positioned on the ulnar side of the trackball  32  and their positions enhance the user&#39;s options for interfacing and operating the input device  20 . Further, the back button  37  is positioned immediately adjacent to the ball  32  and the forward button  39  is positioned immediately adjacent to the back button  37 . As these buttons  37  and  39  can be important input tools for certain computer programs, such as a browser, their convenient positioning enhances comfort and reduced fatigue. As there are a number of comfortable interfacing positions, the user may switch between alternative comfortable hand positions to prevent certain repetitive movement injuries. 
     For example, the user may choose to operate the trackball  32  solely by his or her index finger  106 , as shown in FIGS. 9,  10 , and  12 , or by using his or her index and middle fingers  106  and  111 , as shown in FIG.  11 . The use is comfortable in either operating arrangement. If the user chooses to operate the trackball  32  by his or her index finger  106  only, as shown in FIGS. 9,  10 , and  12 , the back button  37  is conveniently positioned for use by the middle finger  111 . The forward button  39  is conveniently positioned for use by the ring finger  120  or by the middle finger  111  moving over from the back button  37 . 
     The shape of the finger supporting surface  96  and the positioning of the ball  32  with respect to the back button  37  enables the user, if desired, to use his or her middle finger  111  to participate in the control of the ball  32 , as shown in FIG.  11 . The user then has another option to dedicate his or her middle finger  111  in assisting with the movement of the ball  32 , or to naturally move the middle finger  111  between the ball  32  and the back button  37 . If the middle finger  111  is dedicated to assisting in the control of the ball  32 , the back and forward buttons  37  and  39  may be respectively operated by the ring finger  120  and the little finger  124 . If the user desires to move his or her middle finger  111  to assist with the buttons  37  and  39 , the forward button  39  may be operated by either the ring finger  120  or the middle finger  111 . 
     Regardless of the hand positioning chosen for operation, the buttons  37  and  39  are positioned and oriented for reach by the middle and ring fingers in the natural direction of movement along the axis of adduction and flexion. The buttons  37  and  39  are actuated by a generally downward applied force by the desired finger by a flexion movement. This prevents the user from having to rotate or twist their fingers awkwardly to depress the buttons  37  and  39 . 
     In an alternate arrangement, as shown in FIGS. 14-17, a switch actuator  130  or  140  having a sliding or pivoting member is used on the ulnar side of trackball  32  in lieu of the back and forward buttons  37  and  39 . In a preferred arrangement of each, a three-position switch is used. The switch  130  or  140  preferably includes neutral center position and first and second active positions which provide certain input signals such as back and forward. However, it is recognized that one or more two position switches may be used, and each such switch would have a neutral position, and an active position that provides a desired input signal. 
     If a sliding switch  130  is used, as shown in FIGS. 14 and 15, the switch  130  includes a finger interfacing sliding member  138  that is movable within a groove  139  associated with the housing  22 . The switch  130  is positioned for convenient use by either the middle finger  111  or the ring finger  120 . The sliding member  138  is biased to a center neutral position  132  as shown in FIGS. 14 and 15. By moving the desired finger forward or backward, the sliding member  138  will move respectively forward or backward in its groove  139  against its biasing to place the sliding member  138  in a forward position  134  or a backward position  136 . Such an actuation will send an appropriate signal to the computer  40 . For example moving the sliding or pivoting element forward or backward may be used to provide a forward or back command signal, respectively, or vice versa, to an internet browser program. The biasing will return the sliding member  138  to its neutral position  132  upon the user releasing the applied force. 
     In the embodiment shown in FIG. 14, the sliding member  138  moves along a substantially horizontal axis parallel to the work support surface  25 . In the alternative arrangement of FIG. 15, the sliding member  138  moves along an axis oriented generally parallel to the user&#39;s middle or ring finger in use as can be seen from the comparison of FIGS. 12 and 15. However, it is recognized that other orientations may be used. 
     If a pivoting switch  140  is used, as shown in FIGS. 16 and 17, the switch  140  includes a finger interfacing pivoting member or rocker  148  that is pivotally coupled to the housing  22 . The switch  140  is positioned for convenient use by either the middle finger  111  or the ring finger  120 , or the middle finger  111  and the ring finger  120 . The rocker  148  is biased to a center neutral position, as shown in FIGS. 16 and 17. By moving the desired finger or fingers forward or backward toward the front  144  or the rear  146  of the rocker  148 , the rocker  148  will pivot respectively forward or backward against its biasing to place the rocker  148  in a forward position or a backward position. Such an actuation will cause the input device  20  to send an appropriate signal to the computer  40 . The biasing will return the rocker  148  to its neutral position upon the user releasing the applied force. 
     In the embodiment shown in FIG. 16, the rocker  148  pivots in a substantially horizontal plane that it parallel to the work support surface  25 . In the alternative arrangement of FIG. 17, the rocker  148  pivots in a plane generally coincident to the user&#39;s middle or ring finger in use as can be seen from the comparison of FIGS. 12 and 17. However, it is recognized that other orientation may be used. 
     The sliding or pivoting switch  130  or  140  is preferably positioned for reach by the middle and/or ring fingers  111  and  120  for activation by the user in a natural direction of movement along the axis of flexion and extension of the middle and ring fingers  111  and  120 . As with the back and forward buttons  37  and  39 , the design allows the user many comfortable interfacing positions, enabling the user to switch between alternative comfortable hand positions to prevent certain repetitive movement injuries and to achieve maximum functionality. 
     For example, the user may choose to operate the trackball  32  solely by his or her index finger  106 , or by using his or her index and middle fingers  106  and  111 . The use is comfortable in either operating arrangement. If the user chooses to operate the trackball  32  by his or her index finger  106  only, the sliding or pivotal switch  130  or  140  is conveniently positioned for use by the middle finger  111  and/or the ring finger  120 . 
     The shape of the finger supporting surface  96  and the positioning of the ball  32  with respect to the switch  130  or  140  enables the user, if desired, to use his or her middle finger  111  to participate in the control of the ball  32 . The user then has another option to dedicate his or her middle finger  111  in assisting with the movement of the ball  32 , or to naturally move the middle finger  111  between the ball  32  and the switch  130  or  140 . If the middle finger  111  is dedicated to assisting in the control of the ball  32 , the switch  130  or  140  may be operated by the ring finger  120 . If the user desires to move his or her middle finger  111  to assist with the switch  130  or  140 , the switch  130  or  140  may be operated by either the middle finger  111 , or the middle finger  111  and the ring finger  120 . Accordingly, the orientation and position the switch  130  or  140  provide convenient and comfortable actuation as the switch  130  or  140  is within easy reach by middle and ring fingers and the switch may be actuated with minimal extension and flexion of the finger. 
     While use of the back and forward buttons  37  and  39  or a switch  130  or  140  are useful for forward and back commands for an internet browser program, they may be remapped to provide the commands normally given by the primary and secondary buttons  28  and  30 , and visa-versa. 
     Further, as shown in FIGS. 1,  4 , and  9 , the outer thumb surface  79  and the thumb support surface  84  on the radial or thumb side  71  are elevated from the work surface  25  by an enlarged bottom side section  83 . This raises the thumb  108  and places it in a comfortable location with respect to the remainder of the hand. It also provides a desired slant to the finger supporting surface  96  which is preferably not too large and supports the metacarpal-phalangeal ridge  64 . It also enables the thumb support to support the thumb without restricting thumb motion. The elevated level of the dividing ridge  95  raises the side of the finger supporting surface  96  closest to the thumb. This places the thumb supporting surface  84  and the exposed portion of the wheel  34  for manipulation at an elevation lower than the exposed portion of the trackball  32  that is manipulated. 
     A preferred embodiment is depicted to scale in the drawing figures. It is preferably sized to completely support the entire hand of the user off of the support or work surface  25 . Accordingly, in use, the user&#39;s palm heel of hand, the ulnar side of the hand including the little finger, and the radial side of the hand including the thumb are preferably supported by the device  20  so that they do not touch the surface  25 . In one of an infinite number of arrangements, the length is approximately 6.75 inches and its width is approximately 4 inches. In this preferred arrangement, the scroll wheel  34  preferably has a diameter of approximately 1 inch and the ball  32  preferably has a diameter of about 1.75 inches. Further, in a preferred arrangement, the angle of pronation, as measured at the metacarpal-phalangeal supporting ridge  64 , is preferably under 45 degrees while the angle of extension of the wrist, as measured at the metacarpal region  78  of the middle finger with respect to the arm, or in this case, also the working surface  25 , is preferably between 15 and 40 degrees. Further, in this one arrangement, the scroll wheel  34  preferably has a diameter of approximately 1 inch, and the ball  32  preferably has a diameter of approximately 46 mm. In this same embodiment, the back button  37  is approximately 35 mm by 17 mm, with the forward button  39  slightly smaller. If a toggle  140  or slider  130  is used, one preferred size for these elements is approximately 8 mm by 3.5 mm. However, the invention is not limited to such dimensions and it is recognized that numerous other sizes may be used. Importantly, it is recognized that the housing can be in any of a number of infinite shapes with varying proportions and shapes of actuators. 
     In operation, the user places his or her hand  105  on the computer input device  20 . As the computer input device  20  is sized to accommodate the entire hand  105 , the user may comfortably rest the entire weight of his or her hand  105  on the input device  20  without any part of the hand  105  touching the work surface  25  upon which the input device  20  sits. This total support of the hand  105  may continually exist for all activations of the activators. In this process, the user places his or her thumb  108  on the thumb side  71 , and more specifically, places it on the thumb rest or thumb supporting surface  84 . The user places his or her remaining fingers  106 ,  111 ,  120  and  124  on the finger side  73  so that the upper surface  96  of the finger side  73  comfortably supports the metacarpal-phalangeal ridge  64 . 
     The actuators on the thumb or radial side  71 , that is the primary button  28 , the secondary button  30 , and the scroll wheel  34 , are activated by the user&#39;s thumb  108 . To activate the primary button  28 , the user merely needs to apply a slight force with the thumb  108  in the direction toward the other fingers. To activate the secondary button  30 , the user raises his or her thumb slightly above the scroll wheel  34  and applies a slight force with the thumb  108  in the direction toward the other fingers. To activate the scroll wheel  34 , the user places his or her thumb  108  against the wheel  34  and uses a natural flexion or extension movement of the thumb  108  to move the scroll wheel  34  in the desired direction. Depending upon the size of the user&#39;s thumb  108 , it may be necessary for the user to slightly raise his or her thumb  108  to engage the wheel  34 . When the thumb  108  is not being used to activate the primary button  28 , the secondary button  30 , or the scroll wheel  34 , he or she may rest the full weight of his or her thumb  108  on the horizontal component  91  of the primary button  28 , using the primary button  28  as a thumb rest, without activating the primary button  28 . 
     The actuators on the finger or ulnar side  73 , that is the back button  37 , the forward button  39 , and the trackball  32 , are activated by the user&#39;s remaining finger&#39;s  106 ,  111 ,  120 , and  124  in any of a number of optional configurations as described above. The user may comfortably move the trackball  32  in any desired direction by contacting the trackball  32  with his or her index finger  106 , as shown in FIG. 10, or by his or her index and middle fingers  106  and  111 , as shown in FIG. 11, and moving his or her finger(s) in a corresponding direction to rotate the trackball  32 . The back button  37  may be activated by pressing generally downward in a natural motion with the middle finger  111  or the ring finger  120  properly positioned over the button  37 . The forward button  39  may be activated by pressing generally downward in a natural motion with the middle finger  111 , the ring finger  120 , or little finger  124  properly positioned over the button  39 . These downward motions to activate the buttons  37  and  39  can be performed by a natural flexion movement the desired finger. If the computer input device  20  has an actuator  130  or  140  with a three-position sliding or pivoting member  138  or  148  in lieu of input buttons  37  and  39 , the user may activate that activator  130  or  140  by sliding or pivoting the member  138  or  148  in a forward or rearward direction. 
     Activating the desired activators will provide a corresponding input signal to the computer  44 . The signals are processed into a corresponding command as determined by a computer program. That command may be used for other programs. The activators may be remapped in a known manner so that certain activators behave to send signals that produce commands normally expected by other activators. For example, the input buttons  28 ,  30 ,  37  and  39  may be mapped so that the described back and forward buttons  37  and  39  provide signals that result in commands normally expected from primary and secondary input buttons  28  and  30 , and vice-versa. This is beneficial for users having finger usage preferences for certain applications. 
     Having illustrated and described the principles of the present invention in a preferred embodiment, it should be apparent to those skilled in the art that the embodiment can be modified in arrangement and detail without departing from such principles. For example, the invention contemplates using the thumb operable and/or horizontally-oriented scroll wheel on a non-trackball input device such as computer mouse. Accordingly, we claim as our invention all such embodiments as come within the scope and spirit of the following claims and equivalents thereto.