Abstract:
A computer mouse including a base and rotatably coupled controller that permits only circular arc motions where only two radii of curvature are permitted and the radii differ in length. Hand translation is prevented by the device. A contoured hand engaging surface on the controller includes a raised palm seat with a spiral hand seat around the palm seat. Ergonomically-configured selectors are described. The hand motions permitted by the mouse are constrained by a toroidal shape at the interface between a base and a rotatably-movable controller. Selectors include one or more one finger activated keys mechanically linked to an internal electrical selector switch. A thumbwheel selector is also located in the controller.

Description:
FIELD OF THE INVENTION 
     The invention pertains generally to a method and device to assist in entering and manipulating computer data. More particularly, the invention pertains to a mouse for sensing hand movements, producing hand movement data, and communicating with a computer or similar device for positioning a cursor and entering commands to an application running on the computer. 
     BACKGROUND 
     The use of computers and many other electronic devices has become generally dependent on the use pointing devices for communicating, usually in connection with a graphical computer interfaces. Pointing devices are used in general office computing such as word processing, spreadsheet analysis, and data base management. Similarly, pointing devices are used in graphical document preparation and design such as may be done by design engineers, product designers, and architects who use computer-aided design and drafting applications. Additionally, pointing devices of various types are used as remote controls in such areas as vehicle controls, industrial and consumer machine and appliance controls, mapping systems, entertainment systems, and many other to facilitate visual interaction between a user and a computer or computer-based system. 
     A common pointer device is the so-called “mouse.” The traditional mouse comprises basically a movable element that can be positioned by hand at arbitrary locations usually on a planar target surface. The mouse can electronically communicate mouse movements in Cartesian coordinates to a computer. The mouse typically also includes one or more control buttons, selectors, or other actuators that can be used to send commands to applications running on the computer. For example, the mouse might include a button with which the user can command a computer application to “select” an item pointed to on the computer display. 
     The mouse gets its name from a perceived mouse-like similarity of the body of the device with a communication cable extending from one end. However, various forms of wireless “mice” are available, and yet the terminology persists. 
     There exist other forms of computer pointing and commanding devices such as trackballs, joysticks, light pens, touch pens, and the like which provide the same or very similar functionality as a traditional mouse. Likewise, pointing and commanding devices such as touch pads, touch screens, and the like offer mouse-like capabilities. However, the more traditional mouse-type devices remain in use. 
     In 1970, Douglas Engelbart was awarded a patent for an X-Y Position Indicator for a Display System (U.S. Pat. No. 3,541,541), which, along with the development of the graphical interface, provided for operating a computer without typing commands. The Engelbart system, which includes a mouse, was configured to communicate to a computer the instantaneous position of the mouse moving on a planar work surface with planar hand movements. The Engelbart mouse was capable of digitally encoding signals from friction-driven orthogonal mouse wheels as the mouse was moved about on the work surface. There have been many subsequent improvements in encoding technologies for detecting motion of a mouse on a work surface and transmitting a signal to accordingly position a cursor on a computer display. The Engelbart configuration of friction-driven, orthogonally angled tracking wheels was followed by improvements such as a friction driven spheres or balls, the rotation of which were encoded via friction driven discs or optical detectors. The friction driven ball then gave way to technologies for directly sensing the motion of the mouse relative to the supporting work surface by optical means. These technologies eliminated problems with friction failure that sometimes occurred while the mouse was in motion. Such developments improved the sensitivity and reliability of motion sensing in the context of computer input devices. 
     As prior art mouse devices developed, scroll wheel actuators were introduced. The scroll wheel was generally acknowledged as a potential Z-axis positioner for 3-D graphical work. It is used more generally, however, as a special selector or actuator for performing menu scrolling. 
     Some mouse-type devices based on non-planar hand movement have been developed. For example, Barnes (U.S. Pat. No. 5,774,113) disclosed a three-directional mouse on a pedestal. The Barnes device comprises a spherical ball resting on an elevated support and associated electronics that detect the angular orientation of the ball relative to the support. A button was provided on the Barnes device for signaling the computer to move an on-screen icon in the direction indicated by the current ball orientation. Adams (U.S. Pat. No. 5,990,871) disclosed a similar device having a relatively large ball supported on a generally conical or mountain-like fixed base. The Adams ball provides as an ambidextrous hand support. A command button for actuation by a finger of the hand was included in the Adams device. Suzuki (U.S. Pat. No. 6,130,664) disclosed an input device designed to operate on a non-planar surface. A curved lower surface of the input device of Suzuki is configured to rest on any work surface and to roll along the surface. Velocity sensors are used in the Suzuki device to detect motion of the device relative to the surface. 
     In some cases, computer operators working in graphic design, engineering design, architectural design, and the like use so-called trackball devices as pointers for cursor control. Such devices are said to provide for selection of a point, such as a specific display pixel, without the selection action moving the device and thus the display cursor. Pressing a selector button without at least some movement may be found in some cases to be difficult with some mouse devices because the action of pressing the selector key often moves the mouse body and thus the cursor. However, cursor motions driven by a track ball device are said to be counterintuitive to many users relative to a combination of X-axis motion and Y-axis motion. 
     As mentioned above, the typical mouse-type device generally includes one or more control actuators, selectors, or buttons for sending application specific commands to the computer along with the position or movement data for the mouse. A typically used selector key may be pressed by the user&#39;s finger and caused to contact an electrical switch configured within the device. A typically-utilized electrical switch of high reliability and low cost has a very short actuation displacement of about one sixty-fourth of an inch (0.015 inch, 0.4 mm). Such devices are typically configured in a mouse where the switch is directly actuated by pressing a key cover positioned directly over the switch. Some users find this configuration unsuitable as to the working tactile sensation of actuation. 
     Currently available mouse-type devices are said to contribute to work-related health problems. For example, mouse usage is thought to be a factor in repetitive stress injuries among information technology workers. Complaints of office workers and other information technology users may include symptoms of repetitive motion disorders possibly related to extended periods of computer mouse usage. Using the human hand to move a mouse on a planar surface is thought to be inherently incompatible with the functional anatomy of the human hand and arm. Such movements may require sizable extensions and retractions of the arm and hand. Wired mouse devices also may sometimes present impediments to movement relative to the wire or cable connecting the mouse to the computer. In some situations, excessive tension may be produced in hand and arm muscles, especially when making precise mouse movements and command selections. Overuse and fatigue of hand and arm muscles may result. Moreover, the placement and configuration of control buttons, thumbwheels, trackballs and the like may be associated with unusual flexion and extension of the fingers which are thought to be tiring and uncomfortable. 
     There remains a need for a mouse-type device that is ergonomically friendly to the human hand and arm and capable of effective precise pointing and command generation. 
     SUMMARY OF THE INVENTION 
     The present invention entails a computer mouse having a hand actuated controller whose movement is dictated or controlled by a toroidal surface. 
     In one embodiment, the mouse includes a controller that rests on a base where the base has a concavity formed therein. The controller includes a lower toroidal surface that projects at least partially in the concavity of the base. A series of spaced apart ball bearings are interposed between the base and the toroidal surface such that as the controller is moved, the toroidal surface engages and moves over the ball bearings. As the surface moves, the controller detects the motion relative to the base. 
     Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a prior art computer mouse device in use. 
         FIG. 2  is a perspective view of a commonly used electrical switch. 
         FIG. 3  is a perspective view of the mouse of the instant invention. 
         FIG. 4A  is a perspective view of a human hand illustrating a “Queen wave.” 
         FIG. 4B  is a perspective view of a human hand illustrating a “Toddler wave.” 
         FIG. 5  is a perspective view of a ring torus with a cut portion. 
         FIG. 6  is a perspective view of the mouse with the controller lifted from the base. 
         FIG. 7  is a front-side perspective view of the mouse. 
         FIG. 8  is a front elevation view of the mouse. 
         FIG. 9  is a right side elevation view of the mouse. 
         FIG. 10  is a back elevation view of the mouse. 
         FIG. 11  is a left side elevation view of the mouse. 
         FIG. 12  is a plan view of the mouse. 
         FIG. 13  is a side elevation view of a selector key in the installed position. 
         FIG. 14  is a perspective view of a selector key in the as-molded position. 
         FIG. 15  is a perspective view of a selector key in the folded-for-installation position. 
         FIG. 16  is a perspective view from the underside of the top shell of the controller. 
         FIG. 17  is a perspective view of the mouse. 
         FIG. 18  is an exploded perspective view of the thumbwheel and primary circuit board assembly. 
         FIG. 19  is a side sectional view of the mouse at cutting plane  19  of  FIG. 12 . 
         FIG. 20  is a fragmentary perspective view of the optical motion sensing assembly. 
         FIG. 21  is a sectional view of the mouse at cutting plane  21  of  FIG. 12 . 
         FIG. 22  is a fragmentary side section view of a ball bearing socket. 
         FIG. 23  is an exploded perspective view of the mouse. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     It is instructive to first consider the basic structure and use of a typical prior art computer mouse, indicated generally by the numeral  30  in  FIG. 1 . Mouse  30  comprises a hand-movable body having a longitudinal axis  30 A and a hand-engaging surface  30 B. The hand-movable body is typically supported on a generally planar work surface  31  such as that of a desk or table. Mouse  30  may be connected to a computer via cable  30 C. Actuators or selectors  32 ,  35 A, and  35 B are included on Mouse  30 . Actuators  35 A and  35 B typically comprise keys or buttons that are mechanically interfaced with a switch such as switch  33  shown in  FIG. 2 . Commonly, switch  33  is mounted interiorly of mouse  30  underneath actuator key  35 A, for example, such that the required movement of the key is the same as that required of plunger  34  for switch actuation. Selector switch  33  is typically connected to circuitry (not shown) capable of sending a signal in response to actuation of the switch. Actuator  32  is typically a scroll wheel that is configured to be actuated by tangential contact with one of the fingers of the user. Scroll wheel  32  is commonly interfaced with hardware and circuitry (not shown) capable of encoding wheel rotation and sending a signal in response to motion of the scroll wheel. 
     Mouse  30  may be engaged by a hand  10  of a user as shown in  FIG. 1 . The user may move mouse  30  about on planar surface  31  to, for example, move a cursor or other icon on a computer display. The user may rotate scroll wheel  32  to, for example, scroll up or down in a menu, and may press either or both of keys  35 A and  35 B to send commands, for example, such as “select” or “open” to a computer application. Movement of mouse  30  about on planar work surface  31  typically requires the user to translate hand  10  in a plane generally parallel to the work surface. Such hand movement may require repeated arm extension and flexion as well as wrist extension and flexion. Actuation of selectors  32 ,  35 A, and  35 B may also require repeated flexion and extension of one or more fingers of the hand. 
     The present invention is a mouse, indicated generally in the drawings by the numeral  46 . For purposes of description herein, mouse  46  is shown in  FIGS. 3 and 7  juxtaposed a reference Cartesian coordinate system  44  having a mutually orthogonal X, Y, and Z axes. For purposes of description only, the Z-axis of system  44  is considered to be vertical. The arrows in system  44  define the positive directions of the respective axes. All references herein to X, Y, and Z axes or directions are with reference to coordinate system  44 . References herein to the tops of features of mouse  46  always refer to aspects of the features that face generally in the positive direction of the Z-axis. References herein to the fronts and backs of any features of mouse  46  refer to aspects of the features that face generally in the positive and negative directions, respectively, of the Y-axis. References to the right and left of any features of mouse  46  refer to aspects of the features that face generally in the positive and negative directions, respectively, of the X-axis. 
     Mouse  46  includes a first subassembly or base  43  and a second subassembly or controller  41 . Base  43  and controller  41  share a common longitudinal axis  46 A when the base and the controller are operably engaged. Axis  46 A is parallel to the Y-axis. When operably engaged, controller  41  is supported on base  43 . In one embodiment, controller  41  is configured to be received in and supported by base  43  such that the controller is relatively free in the operative mode to be moved only rotationally relative to the base. Base  43  may rest on a generally planar work or support surface parallel to the X and Y axes of coordinate system  44 . The invention does not, however, restrict the support surface to being planar, nor does the invention restrict the Z-axis of coordinate system  44  to being vertical. 
     Controller  41  comprises a top shell  52 A and a bottom shell  52 B. Top shell  52 A and bottom shell  52 B are generally bowl-shaped shells that are secured together with respective generally concave aspects facing each other to form the body of controller  41 . Top shell  52 A includes a generally upward facing hand receiver or hand-engaging surface  41 B generally surrounded by a peripheral wall  41 A. The lower edge of wall  41 A generally defines the assembly plane of controller  41 . Openings or cutouts  52 C and  64 A are formed or cut in top shell  52 A for receiving portions of selectors  53 A,  53 B,  53 C and thumbwheel  64 . 
     In one embodiment, the underside of top shell  52 A has formed thereon various supporting structures as shown in  FIG. 16 . There are provided three return spring supports  62 . Blocks  62  are each spaced backwardly from cutout area  52 C of top shell  52 A. A return spring hook or retainer  63  is provided between cutout  52 C and each block  62 . Formed adjacent cutout  52 C are three pairs of spaced apart hook-shaped selector pivot blocks  61 . A thumbwheel circuit mounting strut  70  is formed adjacent cutout  64 A. A rib  100  is formed across top shell  52 A, spaced backwardly from return spring support blocks  62 . Bosses  52 D are formed adjacent sides of top shell  52 A. 
     Bottom shell  52 B includes a base-engaging surface  40 . Surface  40 , in one embodiment, is convexly-shaped and curves upwardly to meet a lower edge of peripheral wall  41 A when connected to top shell  52 A. Formed in bottom shell  52 B and extending generally upward from surface  40  are a pair of recesses  101 A that include fastener openings for receiving fasteners or screws  101 . In one embodiment, base engaging surface  40  also includes an opening  47  that provides a motion sensing system port, which system will be discussed below. Shells  52 A and  52 B may be formed of polymeric material by various fabrication methods including casting and injection molding. 
     Top shell  52 A and the bottom shell  52 B are, in one embodiment, secured together by screws  101  extending in recesses  101 A through the fastener openings and into mounting bosses  52 D that are molded on the underside of the top shell (see  FIG. 16 ). Shells  52 A and  52 B enclose an interior space and surfaces for mounting other components of mouse  46  as described below. An electrical cable  81  may be provided for electronic connection of mouse  46  to a computer. 
     Turning now to base  43 , the base includes a base shell  106 , or wall, generally defining a periphery of the base as shown in  FIG. 6 . Base  43  may be of a generally oval or elliptical shape as illustrated, although other shapes may be utilized. In one embodiment, a concavity  43 A is formed in base  43 . Concavity  43 A includes a generally central depressed area  48  and an upwardly curved annular inner skirt portion  43 B extending upward and outward from area  48  to form a bowl-like shape. Inner skirt  43 B is peripherally bounded by a base rim  43 C forming generally annular surface that encircles concavity  43 A and forms a topmost surface of base  43 . In one embodiment, base  43  includes a controller support system comprising spaced-apart bearings  42  and motion damping pads  51 , both of which are discussed below. 
     Base  43  may include a snap-in bottom plate  109  that provides load distribution and a resilient foot  110  that prevents the base from moving relative to the support surface. Bottom plate  109  may provide a place for labeling by molding, printing, or applying an adhesive label. Base  43  may be formed of polymeric material by various fabrication methods including casting and injection molding. 
     Turning now in more detail to controller  41  and base-engaging surface  40 , in one embodiment the base-engaging surface is a toroidally shaped guide surface. The toroidal shape of base-engaging surface  40  may be defined by an outer surface  38 A of a ring torus  39  as shown in  FIG. 5 . Ring torus  39  is a geometric solid that is formed by rotating a generating circle  39 A about an axis  39 B that is co-planar with the circle. Diameter D 1  is greater that diameter D 2  of ring torus  39 . The center of the generating circle describes a circular path  39 D. Circular path  39 D is actually the locus of tangency points of the central axis of generating circle  39 A and can be referred to as circular axis  39 D. A segment  38  of ring torus  39  is formed by passing a cutting plane  39 C that is parallel to and offset from axis  39 B through the torus. Segment  38  is shown offset from the remainder of ring torus  39  in  FIG. 5 . Outer surface  38 A of segment  38  has a longitudinal axis  38 B. It is appreciated that surface  38 A is circularly curved about two mutually normal axes: axis  39 B and circular path or axis  39 D. Moreover, the radius of curvature, D 2 /2, about circular axis  39 D is smaller than the radius of curvature, D 1 /2, about axis  39 B. 
     When the shape of surface  38 A is implemented to form toroidal base-engaging or guide surface  40 , axis  38 B is parallel to the plane defined by the Y axis and the Z axis and torus-generating axis  39 B is parallel to the plane defined by the X axis and the Z axis. When controller  41  is operably engaged with base  43 , toroidal base-engaging surface  40  is generally contained in concavity  43 A of the base and engaged with the support system. 
     To support controller  41  on base  43 , in one embodiment the support system is deployed in the base and contacts toroidal base-engaging surface  40  of the controller. In one embodiment, the support system includes a series of four spaced-apart ball bearings  42  mounted in concavity  43 A, as mentioned above. Sockets  102  and retainers  103  for holding ball bearings  42  are formed in concavity  43 A in one embodiment. See  FIGS. 21 and 22 . One pair of bearings  42  deployed near a front end portion of base  43  and another pair disposed at an opposite, or rear, end portion as shown in  FIG. 6 . Bearings  42  project from base  43  such that their centers lie on a toroidal surface that generally matches the toroidal shape of base-engaging surface  40 . Retainers  103  are configured to permit snapping bearings  42  into the sockets  102  by temporarily deflecting the retainers. Bearings  42  project into concavity  43 B a distance sufficient to provide adequate clearance between controller  41  and base  43  when the controller is supported on the bearings and rotated about on the bearings. Sockets  102  and retainers  103  may, in one embodiment, be directly molded as a feature of the base  43  via a double shut-off retracting ejector in the mold tool (not shown) for each location. 
     To, in part, further support and dampen movement of controller  41 , damping pads  51  are utilized in one embodiment. Each pad  51  may be a relatively compliant friction pad seated in a recess or damping pad socket  108  formed in concavity  43 A. See  FIGS. 6 and 23 . In one embodiment, pads  51  are adhesively bonded in recesses  108 . Pads  51  provide friction damping of motion of controller  41 . In one embodiment, two pads  51  are utilized, one adjacent each bearing  42  in the rear end portion concavity  43 B. 
     Supported as described above, controller  41  may only be rotated relative to base  43 . Controller  41  cannot translate relative to base  43 . Moreover, controller  41  can only be rotated about the X and Y axes; the controller cannot rotate about the Z axis. In use, controller  41 , may be rotated by hand  10  engaged generally with mouse  46  as shown in  FIG. 7 . The movements of hand  10  to control the position of controller  41  in base  43  may comprise only circular arcs of motion about the X and Y axes or combinations of the two circular arcs. Because of the toroidal shape of base-engaging surface  40 , the radius of any circular arc of motion about the X axis is different from the radius of any circular arc of motion about the Y axis. In one embodiment, the radius of any circular arc of motion about the X-axis is larger than the radius of any circular arc of motion about the Y-axis. 
     The motions of hand  10  required to control the position of controller  41  relative to base  43  may also be described as so-called queen wave  36  and toddler wave  37  motions. See  FIGS. 4A and 4B . Mouse  46  is thus configured to permit pointer position control on a computer, for example, by motions of hand  10  limited to rotational or circular motions consistent with natural hand rotations. This configuration also blocks hand motions that may cause traditional mouse related injuries. 
     Turning now to the details of provisions for engaging hand  10  with mouse  46 , hand-receiver or hand-engaging surface  41 B, includes a raised contoured palm seat  41 C and a depressed contoured hand seat  41 D. Raised palm seat  41 C comprises a mound or upwardly projecting protuberance shaped to receive palm  10 C of hand  10 . Hand seat  41 D, viewed from above, exhibits a generally spiral shape depression that partially wraps around palm seat  41 C as shown in  FIG. 12 . The depression of spirally disposed hand seat  41 D is shaped to conform generally to the palmar aspects of hand  10  that surround palm  10 C. More particularly, depression  41 D follows a generally spiral path starting at about point  1 , corresponding approximately to index finger base knuckle pad at area  10 D of hand  10 . See also  FIGS. 4A and 4B . The path continues clockwise across top shell  52 A to about a point  2 , corresponding approximately to side palm  10 E. Thence, the path continues to point  3  approximately corresponding to heel  10 F, from whence the path curves around to about point  4 , corresponding approximately to thumb base  10 G and completing spiral around palm seat  41 C. The depression of hand seat  41 D is contoured generally upward and towards palm seat  41 C to provide a smooth transition between the hand and palm seats. 
     Hand seat  41 D is surrounded by a generally sloping skirt portion  41 E. Front portion  41 F includes cutout  52 C where selector keys  53 A,  53 B, and  53 C project. Skirt  41 E extends rightward where the skirt narrows and extends rearward around the right side of hand seat  41 D. Skirt  41 E widens as it extends around the rear of seat  41 D and merges with portion  41 F. Portion  41 F corresponds generally to thumb  10 B of hand  10 . Included in thumb portion  41 F is cutout  64 A where thumbwheel  64  projects. In one embodiment, portion  41 F of skirt  41 E is sloped in a horizontal plane at an acute angle relative to the longitudinal axis  46 A. The angle approximates the angle of longitudinal axis  10 H of thumb  10 B relative to palm  10 C in relaxed human hand  10 , or approximately 20-35°. The actual dimensions of hand seat  41 D and skirt  41 F may be varied to accommodate implementations of mouse  46  for users with widely varying hand sizes. Standard anthropometric data may be employed along with plaster models of average-sized hands to produce the contoured shapes described above of hand-engaging surface  41 B. Hand-receiver  41 B can be formed of a polymeric material through any of various plastic part forming methods including casting and injection molding. 
     Mouse  46  includes a circuit board assembly that comprises a primary circuit board  56  secured to a thumbwheel circuit board  68 . Pertinent aspects of circuit boards  56  and  68  are described below relative to supported elements. Generally, however, circuit board  56  is mounted inside bottom shell  52 B. Thumbwheel circuit board  68  is mounted perpendicularly to primary circuit board  56 , tabs  68 A being inserted into slots  69 . Thumbwheel circuit board  68  is inserted into support strut  70 . 
     Turning now to the motion sensing system for detecting the rotational position of controller  41  relative to base  43 , in one embodiment an optical motion sensing system is utilized. The motion sensing system includes an optical illuminator  84  mounted in the interior of controller  41  to illuminate a portion of base  43  by directing a light beam though opening or port  47  in base shell  52 B. See  FIG. 19 . The system further includes an optical detector  83  to detect movement relative to the illuminated portion of base  43 . Central depressed area  48  forms, in this embodiment, a target area that is sufficiently large to include any area that can be possibly illuminated as controller  41  is rotated in base  43 . Central depressed area or target area  48  is printed or textured with features to optimize motion detection. Such printing and texturing is well known in the art. 
     Optical detector  83  (see  FIG. 19 ) and associated illuminator or LED  84  are mounted on a stiffened portion  85  of a flexible printed circuit  86 . An LED cage  88  is provided and includes a support post  88 A with an upwardly projecting notch or yoke. A lens and prism component  87  is also provided. In assembly, LED cage  88  and lens and prism component  87  sandwich stiffened portion  85  and interlock to secure the LED cage  88  and lens/prism component  87  to the stiffened portion of flexible printed circuit  86 . Flexible printed circuit  86  mates with FPC connectors  82  on primary circuit board  56  and is suspended between the primary circuit board and the upper side of bottom shell  52 B. Flexible printed circuit  86  includes a pair of upwardly-extending leg portions  86 A and a curved scoop-like shape  86 B holding stiffened portion  85 . See also  FIG. 23 . Flexible printed circuit  86  is suspended from the primary circuit board  56  by leg portions  86 A. 
     For attaching flexible printed circuit  86  to bottom shell  52 B, a back hook tab  90  and a front hook tab  91  are formed in the upper or interior side of bottom shell  52 B as shown in  FIG. 19 . Each of hook tabs  90  and  91  includes a hook portion  93  with an open side. The open side of hook portion  93  on back hook tab  90  faces in the opposite direction from that of the open side of the hook portion on front hook tab  91 . The top of hook portion  93  is configured to act as a cam to aid assembly. An upwardly-sloping surface  96  terminates in a curved upper portion  96 A in each hook portion  93 . A wire retainer  89  is provided to attach flexible printed circuit board  86  to hook tabs  90  and  91 . 
     Wire retainer  89  is, in one embodiment, a length of spring steel wire including a center section  92  with bend-backs  95  at opposite ends of the center section. Each bend-back  95  includes two ninety degree bends,  94 A and  94 B. Bend-backs  95  lie in a common plane and extend opposite in directions from each other. In assembly, retainer  89  is slightly bent and twisted by engaging one bend-back  95  into back hook tab  90  and resting center section  92  in the yoke of support post  88 A. The end portion of center section  92  thereby made adjacent to front hook tab  91  may then be slid laterally over the cam portion of the top of the hook tab until it snaps into curved upper portion  96 A. As the retainer  89  is pushed into place, the bend-back end portion  95  at hook tab  90  impinges on the closed side of hook tab  90  and results in a torque on center section  92 . The end portion of center section  92  adjacent hook tab  91  can then be guided along camming surface of  93  until the end portion seats into curved end portion  96 A of the hook tab. When the end portion of center section  92  seats against curved upper portion  96 A, bend-back  94  at the end of the wire has clearance to allow the torsion to relax and snap retainer  89  into a secure hold-down position where the center section remains bent over post  88 A. 
     The motion sensing system of the embodiment described above enables generation and transmission of signals from mouse  46  to a computer. These signals describe the instantaneous position of controller  41  in base  43  as the controller is rotated about the X and Y axes while being supported by the base. The computer interprets these signals to position a cursor, for example, on a computer display. 
     Turning now to the actuators or selectors deployed in mouse  46 , the actuators include, in one embodiment, the above mentioned three selector or actuator buttons  53 A,  53 B, and  53 C along with a thumbwheel  64 . A user may engage controller  41  with hand  10  as, shown in  FIG. 7 , in a manner such that fingers of the hand may contact buttons  53 A,  53 B, and  53 C and the thumb of the hand may contact thumbwheel  64 . As discussed above, selector buttons  53 A,  53 B, and  53 C and thumbwheel  64  extend in cutouts  52 C and  64 A, respectively, and are electrically connected to conventional circuitry (not shown) on primary circuit board  56  and thumbwheel circuit board  68 . This circuitry translates, by well known methods, the actuating motions of one or more of the fingers  10 A and of the thumb  10 B of hand  10  into signals and transmits the signals to, for example, a computer. 
     In one embodiment, selectors  53 A,  53 B, and  53 C are of generally the same design, and each selector is configured to actuate a separate selector switch  33 . Accordingly, the structure of selector  53 A and assembly with switch  33  will be described with reference to  FIGS. 13 ,  14 , and  15 . 
     Selector switch  33  is mounted on primary printed circuit board  56  whereby the switch is supported and also electrically connected to circuitry of well known design for transmitting a signal from mouse  46 . Primary circuit board  56  is configured to be mounted within controller  41  as shown in  FIG. 19 . Selector  53 A includes a generally arcuate shaped formed by a main strut having a key  54 A with contact surface  54 B, a link support portion  54 C, a transfer link  54 D, and a cam link  60 . Disposed on key  54 A is a finger contact surface  54 B extending over front and upper surfaces of the key. An elongated return spring  57  forms a portion of key  54 A that extends rearwardly and downwardly in a cantilever fashion. Return spring  57  is configured to partially enable mounting selector  53 A on an underside of top shell  52 A of controller  41  and to provide a restoring force to return the selector to an unactuated orientation. 
     Link support portion  54 C of main body  54 A extends rearwardly and downwardly adjacent return spring  57 . As can be appreciated from  FIGS. 14 and 15 , return spring  57  and link support portion  54 C are laterally offset from each other. Disposed near the origination of return spring  57  is a journal  61 A with journal struts  61 B and  61 C extending normally thereto. Journal  61 A defines a selector rotation axis  55 . Struts  61 B and  61 C cooperate with return spring  57  to provide for securing selector  53 A operably within controller  41  as will be discussed further here below. 
     Transfer link  54 D is pivotably connected to link support portion  54 C by a first hinge  60 A. The facing ends of transfer link  54 D and link support portion  54 C are beveled so that, when in an assembled or folded position as shown in  FIGS. 13 and 15  the facing ends meet and an arcuate shape is assumed by the combined main body  54 A and transfer link  54 D. Cam link  60  is connected to transfer link  54 D by a second hinge  60 B, and facing ends of cam link  60  and transfer link  54 D are shaped in a complementary fashion so that, when in an assembled or folded position as shown in  FIGS. 13 and 16  the facing ends meet and the cam link  60  extends generally normal to the transfer link  54 D. Cam link  60  is formed as a spring arm that can be pre-loaded during assembly. 
     An enlarged end portion of cam link  60  forms a cam  58  that is disposed adjacent switch follower button or plunger  34  when selector  53 A is assembled with switch  33  as shown in  FIG. 13 . Cam  58  includes a lower surface  58 A to rest adjacent plunger  34  on an upper surface  33 A of switch  33 . Cam  58  also includes a camming surface  58 B disposed generally on the underside of the cam. When selector  53 A is assembled with switch  33 , cam surface  58 B is close to but does not depress plunger  34 . In one embodiment, camming surface  58 B may include a concave conical surface for keeping cam  58  generally centered on plunger  34 . 
     While selectors  53 A,  53 B, and  53 C may be of generally the same design, it is appreciated that actual dimensions may vary. For example the size of finger contact area or surface  54 B may be different among the selectors. Likewise, the lengths of link support portion  54 C, return spring  57 , transfer link  54 D, and cam link  60  may be of various sizes to accommodate varying actuation forces and distances. Selectors  53 A,  53 B, and  53 C may be formed of a polymer material by any of various plastic part forming methods including injection molding. The polymer and the forming method should be chosen to provide a durable spring-like quality to the structure. Selectors  53 A,  53 B, and  53 C can be molded in flattened configurations, as illustrated in  FIG. 14 , and then folded and snap locked into shape as shown in  FIG. 15 . Snap locking is provided for by well known latch structures  60 C formed adjacent the first and second hinges  60 A and  60 B. 
     Turning now to the installation of a typical selector  53 A in top shell  52 A, the selector may be installed by guiding return spring  57  under retainer  63  and resting an end portion of the return spring on block  62 . Journal  61 A may be slid into engagement under portions of pivot blocks  61  such that selector  53 A extends in cutout  52 C and is snapped into place. Resulting pre-load on return spring  57  preload provides tactile feedback without backlash. So mounted, selector key  53 A has an actuation arc generally about axis  55 . 
     Selector circuit board  56  is mounted to the upper side, or inside of bottom shell  52 B as discussed above. Placement of circuit board  56  is such that cam  58  rests against top surface  33 A of switch  33  and camming surface  58 B is immediately adjacent plunger  34  as mentioned above. Placement of circuit board  56  further provides that plunger  34  be generally aligned with a normal to circuit board  56  that passes through journal  61 A. Further, the placement of circuit board  56  provides the pre-load mentioned above of cam link  60  due to deflection of the link as cam  58  is engaged with selector switch  33 . 
     The selector key installation described above enables actuation of switch  33  with sufficient travel of finger surface  54 B to provide a tactile motion that is thought to improve user sensation of actuation. Actuation of electrical selector switch  33  is achieved by pulling a finger that is in contact with finger contact area  54 B toward the palm of the hand similarly to pulling a trigger. Because the force for actuation is resolved against the palm of the hand on the controller  41 , there is no residual load to disturb the cursor position. With proper hand engagement, pivot axis  55  is located as close as possible to the finger joint being used for actuation. Selector  53 A rotates in unison with the respective middle and distal phalanges of the finger when the key pulled. The other keys  53 B and  53 C function similarly. 
     This configuration can provide reliably functional keys  53 A,  53 B, and  53 C over the range of accumulated manufacturing tolerance variations. This configuration also provides for protecting the electrical switch  33  from the excessive pressure that may be caused by an excited user as cam link  60  can only deliver a limited force to electrical switch  33 . 
     Turning now to the thumbwheel  64  and implementation thereof in one embodiment, it is appreciated that the thumbwheel is mounted such that a portion of the thumbwheel projects through thumbwheel opening or cutout  64 A in the shell  52 A. See  FIGS. 16 and 17 . Thumbwheel  64  is mounted on a thumbwheel circuit board  68  as discussed above (see  FIG. 18 ). Thumbwheel  64  is of a known rotating grid type with a cylindrical wheel  71 , a soft tire  72 , a two piece cage  73 , an LED light source  74 , an optical detector  75 , and a header pin socket  76  mounted to a small circuit board  68 . A resilient rub block  77  is mounted as the scroll wheel brake or damper. Rub block  77  provides slight tactile resistance during actuation of thumbwheel  64  and prevents the thumbwheel from drifting when it is not being moved by the user. 
     Thumbwheel  64  is mounted such that the axis of rotation  65  of the wheel is parallel to the Y-Z plane and intersects the X-Y plane when controller  41  is in the neutral position. Generally, the angle between thumbwheel axis  65  and the assembly plane of the top shell  52 A and the bottom shell  52 B is approximately 15°. This angulation of axis  65  provides for the axis to extend generally through thumb base  10 G, including generally through the metacarpal-carpal joint of the thumb  10 B, when hand  10  is engaged with hand receiver or hand engaging surface  41 D. 
     Thumbwheel circuit board  68  is mounted perpendicular to the primary circuit board  56  which is mounted at an angle in the bottom shell  52 B of the controller  41  to provide the needed alignment, as discussed above, of rotation axis  65  of thumbwheel  64  and to enable positioning electrical selector switches  33  of primary circuit board  56  as here before described. In addition to the electrical selector switches  33 , the primary circuit board  56  carries a header pin array  78  to electrically connect the thumbwheel circuit board  68 , a connector  80  for the cable  81 , two flexible printed circuit (FPC) connectors  82  and any other applicable and known electronic components. 
     A ballast weight may be necessary to balance the controller  41  against off-center weight of thumbwheel  64  and selectors  53 A,  53 B, and  53 C and to define a quiescent position of the controller. In one embodiment a weight  97  is provided that fits over a post  98  molded on the inside of bottom shell  52 B. Ballast weight  97  compresses two resilient pads  99  mounted on struts formed in bottom shell  52 B. See  FIGS. 19 and 23 . When shells  52 A and  52 B are secured together as here before described rib  100 , positioned above weight  97  provides further retention of weight  97 . 
     As has been discussed above, variations in sizes of various portions of mouse  46  may be made to accommodate different types of users. For example, the dimensions of hand-engaging surface  41 B may be optimized for various hand sizes. Likewise, various components having different structural properties may be installed. For example, damping pads  51  may be of various kinds that have different frictional properties. Because controller  41  is supported by ball bearings  42 , the frictional damping provided by pads  51  is generally independent of the hand-applied weight. Replacing particular pads  51  with others having more or less frictional resistance with base-engaging surface  40  can provide an increase or decrease of frictional damping, thereby adapting the device to personal preferences. Another example is related to rub block  77  associated with thumbwheel  64 . Blocks  77  of varying stiffness may be substituted to match user preference as to tactile resistance, for example. Likewise, different users may prefer different quiescent positions for controller  41  when the controller is not being moved or engaged by the hand. Ballast weights  97  of different sizes may accordingly be utilized. 
     All references in this description are relative to a right hand version of mouse  46 , but the invention also applies to a mirror image version for left-handed use. The current invention is also not limited as to the dispositions of the optical target  48 , motion illuminator  84 , and the optical motion detector  83 . Target  48  could be located on controller  41  with motion illuminator  84  and motion detector  83  being disposed in base  43 . Likewise, it would be a matter of design choice to dispose concavity  43 A on the underside of controller  41  and toroidal surface  40  on base  43 . Additionally, the instant invention is not limited as to the optical method and apparatus for sensing motion described. It is recognized that other forms of motion sensing can be employed without limiting the scope of the present invention. 
     As used throughout this description, the terms such as top, upper, bottom, lower, and similar gravity-related terms are used only to facilitate description of a particular embodiment in a particular orientation and are not to be understood as limiting the invention as to the orientation of mouse  46 . 
     The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the scope and the essential characteristics of the invention. The present embodiments are therefore to be construed in all aspects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.