Abstract:
A computer keyboard incorporates a base member, a keying module and a spacing member coupled therebetween. The spacing member is pivotable over a range of angles to allow the keying module to be retained at a range of discrete, desired angles above a support structure such as a desktop. An embodiment incorporates two such assemblies linked together by a sliding member, further allowing the keying modules to be spaced apart laterally from each other by a desired distance. Another embodiment incorporates a hinged linking member, allowing the keying modules to also be angled with respect to each other about an axis normal to the support plane.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 60/647,546 filed Jan. 27, 2005, where this provisional application is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The field of the invention is that of ergonomic computer keyboards, specifically high-performance ergonomic keyboards intended to improve comfort and productivity compared to the conventional computer keyboard. Such high-performance computer keyboards are intended combine small size and easy-to-use features to improve comfort by minimizing the unnecessary strain, awkward postures, and excessive force associated with using the traditional computer keyboard, the latter having evolved more or less directly, without significant improvement, from a combination of the typewriter and the adding machine. Productivity benefits may be achieved by increasing the speed and/or accuracy of data entry or editing, or when stamina and work availability are increased. Appropriately-designed high-performance computer keyboards may also provide improved comfort and productivity when using pointing devices such as mice, trackballs, and touchpads (hereafter collectively termed “mouse or mice”), by facilitating improved posture and reduced reach, especially for right-handed mouse users. 
     2. Description of the Related Art 
     Origins of the Typewriter and Numeric Keypad 
     As is generally known in the field, the typewriter was invented in the late 1800s. What is less well known is that in the early 1900&#39;s, the rapid pace of industrial innovation led to credible attempts at improving the typewriter keyboard, including splitting it into right and left segments (e.g. McNamara, 1921 and Tyberg, 1926) and streamlining the layout of the keys (and Dvorak, 1936). However, in spite of the numerous improvements invented in this time period, the commercial typewriter became standardized on the less effective Sholes&#39; design without substantial changes to its geometry or the organization of the keys. 
     The static design of the typewriter was probably due in part to the rapidly-established dependence of both workers and employers on standardized, and “portable” methods and equipment for written communications. Even though it was far from optimal by modern standards, the typewriter was a powerful productivity tool compared to writing longhand. It took substantial practice and skill to become proficient using a typewriter (in part because of its non-optimal design), and when proficiency was attained by students and job trainees, there were powerful social and economic forces resisting any changes that would have required retraining. Another phenomenon that retarded keyboard evolution in this period was the mechanical complexity of the devices. The equipment was limited by inflexible mechanical constraints. 
     The numeric keypad, which is an important part of the now-traditional computer keyboard, experienced an evolutionary path independent of the typewriter. 
     Perhaps because of the more diverse uses to which this type of device was subjected, or because it was simpler to learn and use a variety of configurations, or because some models were highly effective for specialized tasks, numeric keypads (adding machines) were produced in a variety of layout\s through the early 1900&#39;s. The invention of the compact 10-key adding machine dates to 1914 (patented by David Sunstrand). Much larger adding machines with far more keys (with columns of numbers dedicated to each decimal position) were in use even into the 1970&#39;s. 
     Computer Keyboards 
     The first computer terminal keyboards used the same typewriter-style arrangement of keys which had been adopted by earlier teletype machines, except for the addition of several new key actions which had not existed on the typewriter. Even with the invention of the personal computer, still more new key actions were simply added to the perimeter without changing the core typewriter-style layout. The first significant change to the keyboard occurred in 1983 with the introduction of a second-generation personal computer, the IBM XT, when the numeric keypad was added to the right side of the keyboard. 
     The second significant change to the keyboard was in 1986, coincident with the rapidly spreading usage of computers by the majority or office workers and the need for faster on-screen editing and navigation. New dedicated editing and navigational keys were added between the typewriter section and the numeric keypad section, making these new keyboards significantly wider still than their predecessors. This new version of the keyboard was called “enhanced” or “extended,” and has become the de facto standard for virtually all computers. For the purposes of this discussion, this enhanced/extended keyboard design will be called the “traditional” computer keyboard. 
     Evolution of Computer Mousing 
     The computer mouse was invented by Douglas Englebart in 1968 and patented in 1970 (see U.S. Pat. No. 3,541,541). However, it wasn&#39;t until the introduction of the first APPLE® computer in the 1980&#39;s that the computer mouse became an important medium for interacting with computers. And it wasn&#39;t until the introduction by MICROSOFT® in THE 1990&#39;S of the first WINDOWS®-based graphical user interface, after the evolution of the current “traditional” keyboard, that a majority of computer users began to be increasingly dependent on the mouse in their computer work. 
     Increasing dependence on the mouse created problems with the wide traditional computer keyboard. Since most people are right-handed, most computer users with wide traditional keyboards are forced to do extensive precision pointing and clicking while the right arm is extended beyond the right side of the keyboard. With the long-standard key spacing of 0.75 inch, the alphanumeric section of keys is approximately 11 inches wide, while the total width of a traditional computer keyboard is ˜19 inches or more. Because all the non-alpha additions to the traditional typewriter keyboard are to the right side, the right side of the traditional keyboard is approximately 18 inches from the center of the alpha keys (effectively 36 inches in total width). Assuming a typical adult shoulder width of 16 to 20 inches, the average right-handed user (˜80% of the population) would have to reach for the mouse approximately 8-9 inches further out than the ideal front-of-shoulder location. 
     Alternative Computer Keyboards 
     Alternative computer (electronic) keyboard designs began appearing in the patent and scientific literature as early as 1964, some long before the invention of the personal computer (IBM, 1964; Kroemer, 1972; Einbinder 1975; Malt and Hobday 1982; Zipp et al., 1983; McCall, 1983; Nakeseko et al, 1985; Lahr, 1987). Zip et al. in 1983 documented some of the features associated with ergonomic keyboards. For example, they documented that a semi-split keyboard (with a center-back, vertically-oriented pivot point) optimally should have a front-opening range up to approximately 30 degrees; and that tenting is optimal in the range of 10 to 20 degrees, while tenting beyond 20 degrees would cause detrimental effects for most users and tenting less than 10 degrees would not provide maximal relaxation of the forearm muscles. 
     McCall and Lahr described fully-split keyboards mounted on the edge of a desk or to the arms of a chair. Lahr also described a measurement feature for quantitatively determining the position and orientation of the keying modules. 
     The first known commercial alternative keyboard was the Maltron keyboard, a fixed-split design with semi-concave key arrays, and with isolated thumb-operated keypads near the midline of the keyboard which was produced and sold in the United Kingdom in the mid-1980s. The first known commercial letter-based alternative keyboard in the U.S. was the KINESIS® CONTOURED™ keyboard (similar to the Maltron), introduced in 1992. This was followed by the introduction of the Comfort keyboard (a fully-adjustable split keyboard mounted on a long desktop track) in late 1992 and the APPLE® semi-adjustable keyboard (two conventional keying modules linked by center-rear pivot point, with loosely-associated plastic palm rests), in early 1993. 
     Many of the published designs of the 1970&#39;s and 1980&#39;s (Kroemer, 1972; Einbinder, 1975; and Nakeseko et al., 1985) disclose partially-split keyboards with right and left halves rotated to a fixed orientation around a pivot point near the center rear of the keyboard. Sometimes the center of the keyboard was tented slightly. 
     Some keyboard designs commercialized in the 1990&#39;s recognized the importance of combining separation, tenting, and palm rests with a narrow, largely symmetrical shape so the mouse could be positioned more or less directly in front of the shoulder (e.g., the fixed-split CONTOURED™ keyboard from Kinesis Corporation, and fixed or adjustable semi-split keyboards from Cherry Electrical Products, Fujitsu-Siemens, and Acer). 
     The biggest problem with alternative keyboard designs has been achieving a balance of effectiveness (for both comfort and productivity), ease of use (setup and adjustment), familiarity (standard key layout), general appearance, adaptation (minimal or no learning curve), and cost. Historically, more-effective products have had more features and more exotic features and typically have required greater adaptation time. This, in turn, has reduced acceptance. For any two products with equivalent effectiveness, the one which is easier to set up and use with reproducible settings will be preferred as well. 
     The present invention creates for the first time a mainstream adjustable ergonomic keyboard family with highly effective features, each of which is best-in-class in both ease of use and performance. Adjustment mechanisms are easily produced to minimize cost. It requires virtually no adaptation and provides broad versatility. It should meet the needs of virtually anyone desiring significantly more comfort and productivity without an adaptation period, and should experience a high level of acceptability. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed toward improved computer keyboards which effectively address the above three factors of comfort, productivity, and acceptability by balancing solutions to the problems of the traditional keyboard design. Many details of selected embodiments of the invention are described in the following text and illustrated in the corresponding drawings; however, one of ordinary skill in the art having reviewed this disclosure will appreciate that modifications can be made to the illustrated embodiments without deviating from the spirit of the invention. The inventor intends that all of these variations should fall within the scope of this disclosure. 
     In one embodiment, the invention is directed toward a computer keyboard having a base member, a keying module, and a spacing member. The base member has an upper portion, and it is configured to be supported by a structural member. The keying module has a lower portion configured to be positionable adjacent the upper portion of the base member, and it has an upper portion configured to operatively retain a plurality of keys thereon. The keying module is pivotably coupled to the base member such that at least a portion of the keying module is pivotable away from the base member. A spacing member is positioned between the base member and the keying module. A first edge of the spacing member is pivotally coupled to either the base member or the keying module and an opposing second edge of the spacing member is configured to abut the other of the base member and the keying module when the keying module is pivoted away from the base member. The spacing member is movable between a first orientation in which the keying module can be positioned adjacent the base member and at least a second orientation in which the keying module is spaced at an angle away from the base member. The other of the base member and the keying module has a plurality of engagement features adapted to releasably retain the spacing member at a corresponding plurality of angular orientations and to retain the keying module at a corresponding plurality of angles with respect to the base member. 
     In another embodiment, the invention is directed toward a computer keyboard having a pair of base members, a corresponding pair of keying modules, a linking member, and a pair of spacing members. Each base member has an upper portion and is configured to be supported by a structural member. A linking member is coupled between the pair of base members, and is slidable with respect to at least one of the base members such that the base members can be spaced laterally apart from each other. Each of the keying modules has a lower portion configured to be positionable adjacent the upper portion of the respective base member, and an upper portion configured to operatively retain a plurality of keys thereon. Each of the keying modules is also pivotably coupled to one of the base member such that at least a portion of each of the keying modules is pivotable away from one of the base members. One spacing member is positioned between each of the base members and the corresponding keying modules. A first edge of the spacing member is pivotally coupled to the base member and an opposing second edge of the spacing member is configured to abut the keying module when the keying module is pivoted away from the base member. The spacing members are independently movable between a first orientation in which the keying modules can be positioned adjacent the base members and a second orientation in which the keying modules are spaced at an angle away from the base member. Each of the keying modules has a plurality of engagement features adapted to releasably retain the respective spacing member at a corresponding plurality of angular orientations and to retain the keying module at a corresponding plurality of angles with respect to the base member. 
     The illustrated keyboard maintains a close-to-traditional key layout to minimize adaptation and maximize acceptance. Its narrow width minimizes reaching for the mouse and for editing keys, without reducing the standard key-to-key spacing or significantly reducing the size of those editing and modifier keys which are typically oversized. 
     One notable feature of the present invention is its ability to be rapidly and easily converted from a simple split keyboard to a fully adjustable split keyboard. The conversion mechanisms are remarkably simple and the adjustment mechanisms of the fully adjustable embodiments are remarkably simple to carry out. Thus the invention can meet the needs of a wide variety of computer users with a common intermediate product combined with selected field-installable accessories. 
     The net effect of this versatile family of configurations provides for ready acceptance due to minimal adaptation requirements and excellent comfort, as well as full productivity for the majority of computer users. In addition to geometric and mechanical features, novel and useful electronic features are incorporated which further enhance the value of the invention to the user. Specific novel aspects of the key layout are important in providing improved comfort and productivity in the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  is an isometric view of a split keyboard according to one embodiment of the present invention, shown in a first configuration in which the sides are neither spaced apart nor tented. 
         FIG. 2  is a plan view of the split keyboard of  FIG. 1 . 
         FIG. 3  is a front elevation view of the split keyboard of  FIG. 1 . 
         FIG. 4  is a right side elevation view of the split keyboard of  FIG. 1 . 
         FIG. 5  is a plan view of the split keyboard of  FIG. 1 , shown in a second configuration in which the sides are not spaced apart, and one side is tented. 
         FIG. 6  is a front elevation view of the keyboard of  FIG. 5 . 
         FIG. 7  is a plan view of the split keyboard of  FIG. 1 , shown in a third configuration in which the sides are not spaced apart, and both side are tented. 
         FIG. 8  is a front elevation view of the keyboard of  FIG. 7 . 
         FIG. 9  is a plan view of the split keyboard of  FIG. 1 , shown in a fourth configuration in which the sides are spaced apart from each other by a first distance, and both side are tented. 
         FIG. 10  is a front elevation view of the split keyboard of  FIG. 9 . 
         FIG. 11A  is a bottom, rear isometric of the split keyboard of  FIG. 9 . 
         FIG. 11B  is a bottom, rear isometric of a split keyboard according to an alternate embodiment of the present invention. 
         FIG. 12  is a top, rear isometric of the split keyboard of  FIG. 9 . 
         FIG. 13  is a bottom, rear isometric of the split keyboard of  FIG. 1 , shown in a fifth configuration in which the sides are spaced apart from each other by a second distance, and both side are tented. 
         FIG. 14  is a plan view of a portion of a keyboard according to the prior art. 
         FIG. 15  is a plan view of a split keyboard according to yet another embodiment of the present invention. 
         FIG. 16  is an isometric view of a split keyboard according to yet another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Common Features 
     This application claims priority from U.S. Provisional patent application No. 60/647,546, filed Jan. 27, 2005. Applicant shows and describes in this application some of the embodiments disclosed in the provisional application; however, for purposes of clarity, some of the details in the provisional application have not been reiterated herein. As such, applicant incorporates herein by reference the provisional application in its entirety. 
     In general, the split adjustable computer keyboard of the present invention offers multiple configurations to meet different users&#39; needs: it provides simple, reproducible, and sturdy adjustments without requiring complex mechanisms or forceful motions; and it provides integrated, padded, but easily removable palm rests that can be adjusted to the same attitudes as the keying modules. 
     The split keyboard of the present invention lends itself to a variety of embodiments for use in different applications; however, certain features are common to all embodiments. One particular embodiment is illustrated in the enclosed drawings to assist the reader in fully understanding many of the features that could be incorporated in an embodiment of this invention. The inventor appreciates, however, that embodiments of the invention can incorporate other features, and that features shown in the illustrated embodiment could be modified or removed without deviating from the spirit of the invention. On the contrary, the inventor considers all such modifications to fall within the scope of the present invention. 
       FIGS. 1-4  illustrate one particular embodiment of a split keyboard  20  according to the present invention, shown in a fully collapsed and compressed configuration. This particular configuration may be used, for example, for storage or transport, or by someone not seeking to take advantage of the keyboard&#39;s ergonomic benefits (e.g., when multiple persons share a single computer at different times). Also, if the linking plate (discussed below) were removed, a further configuration for storage or transport could be stacking the keying modules or folding the keyboard in half. 
     The split keyboard  20  includes a left keying module  22 L and a right keying module  22 R, positioned side-by-side. The keying modules  22 L, 22 R combine to provide the keys generally associated with a computer keyboard, the keying module on the left carrying the keys typically actuated with the user&#39;s left hand and the keying module on the right carrying the keys typically actuated with the user&#39;s right hand. The particular keys and/or their respective locations can be modified without deviating from the spirit of the present invention. 
     The keying modules  22 L, 22 R are coupled together by a base assembly, which is comprised of a left base  24  and a right base  26  slidably connected to each other via a linking plate  28  (see, e.g.,  FIG. 10 ). The left and right bases  24 ,  26  are configured to be supported by a structure, such as a desk or table, as discussed elsewhere in this disclosure. The left and right bases  24 , 26  are connected to the respective keying modules  22  by means of hinges  30  ( FIG. 4 ) along their lateral distal edges. 
     In the illustrated embodiment, palm rests  32  project proximally from each of the keying modules  22 . It is appreciated that the split keyboard  20  can be designed with unitary palm rests or removable palm rests. Where removable palm rests are used, corresponding removable base-extension elements, which attach to the front (proximal to the user) of each base, can likewise be used. 
       FIGS. 5-8  illustrate the split keyboard  20  in two additional configurations. In  FIGS. 5 and 6 , only the left keying module  22 L has been tented; in  FIGS. 7 and 8 , both the left keying module and the right keying modules  22 R have been tented. As shown in  FIG. 8 , the left and right keying modules  22 L, 22 R can be tented independently, at either the same or different angles with respect to the respective bases  24 , 26 . 
     A left lifting flange  34  is pivotably and reversibly attached to the left base  24  (and a left base-extension, if present), and a right lifting flange  36  is pivotally and reversibly attached to the right base  26  (and a right base-extension, if present). 
     In the illustrated embodiment, the left lifting flange  34  is attached to the left base  24  by a left flange hinge  38 , and the right lifting flange  36  is attached to the right base  26  by a right flange hinge  40 . An individual of ordinary skill in the art, having reviewed this disclosure, will appreciate that the flanges could be hingedly attached to the keying modules, or could be otherwise modified without deviating from the spirit of the present invention. 
     As best illustrated in  FIG. 11A , each of the illustrated lifting flanges  34 , 36  is formed with a tab  42  and locking projections  44 . To tent one of the keying modules  22 L, 22 R, the user of the illustrated embodiment would lift the module while pulling upward on the tab  42  until the keying module is tented to the desired angle. Along the way, the locking projections  44  on the lifting flange  34 , 36  would sequentially contact the slots, each slot corresponding to a different tenting angle. When the user has tented the keying module to the desired angle, the user would merely release the keying module when the locking projections  44  have engaged the corresponding slots  46 . 
     One novel feature of the illustrated embodiment is unexpected tenting range, sturdiness, and ease of positioning provided by the lifting flanges  34 , 36 . The lifting flanges  34 , 36  allow tenting at discrete and reproducible settings, which is desired by both users and ergonomic professionals. Surprisingly, a single lifting flange  34 , 36  on each side can provide very sturdy support for many angles within the range of most desirable tenting angles. Even at the perceived extreme angles for the lifting flange, at the 10 and 30 degree tenting positions, the split keyboard  20  feels very sturdy. The lifting flange  34 , 36  does not perceptibly deflect even when fabricated from inexpensive means and materials, such as injection molding with ABS plastic with normal thickness. 
     In the illustrated embodiment, tenting angles range from approximately 10 degrees to approximately 30 degrees with intermediate positions (15, 20, and 25 degrees, where the untented, flat configuration is considered 0 degrees), all using one support flange  34 , 36  for each keying module  22 L, 22 R. An individual of ordinary skill in the art will appreciate that, with the addition of special, fixed-angle lifting flanges, the tenting angle could be extended to significantly greater angles, including vertical (90 degrees) if desired; though it is anticipated that the preferred configuration for most users will fall in the tenting range of 10 to 30 degrees, and most especially in the range of 10-20 degrees. While it is anticipated that most users will configure each side symmetrically, the user may easily create asymmetrical configurations. 
     Equally surprising is the ease with which the lifting flanges  34 , 36  and keying modules  22 L, 22 R can be positioned at different tenting angles. The user (from the normal operating position) can reach to the back (distal edge) of the split keyboard  20  and simply lifts one or both lifting flanges  34 , 36  (e.g., using, for example, either the first or second finger of the hand) for the corresponding tab  42  which can extend slightly beyond the back edge of each keying module  22 L, 22 R. When the first tenting position is reached, the locking projections  44  fall into it&#39;s the corresponding slots  46  with an easily discernable click, at which time the tab  42  can be released. If a greater tenting angle is desired, the tabs  42  may be lifted further until the desired slot  46  is reached. To lower the keying module  22 L, 22 R, the keying module may be raised slightly (typically with other fingers) while either gravity or a gentle push from the first or second finger lowers the lifting flange  34 , 36 . This process requires neither force nor skill, which increases the likelihood that users will use the desirable tenting feature of the split keyboard  20 . The prior art has never approached this combination of tenting range, sturdiness, and ease of use. 
     Linking Plate 
     As illustrated in  FIGS. 9-12 , fully adjustable split keyboards  20  may be linked together by a linking plate  28 . The linking plate  28  can be fabricated from a rigid but resilient material such as steel, aluminum, or rigid plastic such as glass-filled nylon, or from other suitable materials. The linking plate  28  allows adjustable positioning of the base elements  24 , 26  (and thus the keying modules  22 L, 22 R) in either or both separation distance and rotational orientation. In the illustrated embodiment, the linking plate  28  is slidable with respect to each of the keying modules  22 L, 22 R, allowing different separation distances to be achieved by the user. In the illustrated embodiment, discrete reproducible distance settings can be achieved by appropriately-positioned orifices  48  in the linking plate  28 , which align to engage a self-hinged or spring-loaded latching button  50  (best illustrated in  FIG. 13 ), which at least partially penetrates the orifice when the two are aligned, providing resistance to further movement. 
     The force required to change the separation distance can be adjusted by the relative size and shape of the orifice  48  and the latching button  50 . A final, maximum stopping position can be absolute, by use of one or more mechanical features such as a pin or screw, or relative, by providing progressively greater but not insurmountable resistance. This latter aspect can be accomplished, for example, by providing small orifices  48  which allow only partial penetration by the latching button  50  for the intermediate position stops, and a larger orifice for the terminal position stops, where the latching button penetrates the orifice more deeply and thus creates greater resistance to movement. An individual of ordinary skill in the art, having reviewed this disclosure, will appreciate this and the other means for carrying out such features. In any case, the linking plate  28  may be completely removable in the event that the user desires to rotate the keying modules  22 L, 22 R relative to each other, or to separate the modules more than allowed by the linking plate. 
     In one particular embodiment, the linking plate  28  slides evenly from both sides when the keying modules  22 L, 22 R are gently pulled apart. This can be accomplished, among other ways, by gradually changing the properties of the orifices  48  in the linking plate  28  from the center towards each end. For example, slightly increasing the size of the orifices  48  (detention slot) from the center to the distal opening will require slightly greater force to move to the next position as the keyboard modules  22 L, 22 R are pulled apart, as the latching button penetrates the larger orifices more fully. In some applications, the user may prefer the ability to move only one keying module  22 L, 22 R to the next stop in order to achieve intermediate separation of the modules. This would be possible by, among other ways, holding the linking plate  28  with one hand and pulling on the selected key module  22 L, 22 R with the other hand. The orifices  48  can be produced as a molded component which inserts into the linking plate  28 , —thus providing greater precision, longer life, replaceability, but retaining the strength and low cost of steel for the main body of the linking plate. Alternatively, the latching button  50  could be produced as a component to be snapped into the linking plate  28  and the orifices  48  could be molded into the bottom of the base  24 , 26 . An individual of ordinary skill in the art, having reviewed this disclosure, will appreciate these and other variations that can be made to these features without deviating from the spirit of the invention. 
     In selected embodiments, the linking plate  28  can be pivotable. For example, as shown in  FIG. 9 , the linking plate  28  can be formed from two pieces hinged together. In such an embodiment, a pin  52  can pivotably connect two sides of the linking plate  28  and a slider  54  fixed to one side of the linking plate can track along an arcuate slot  56  in the other side of the plate. The length and orientation of the arcuate slot  56  can dictate the range of motion of the linking plate  28 . Such a pivotable linking plate allows the keying modules to be rotated while still maintained in a defined and reproducible relationship to each other. 
     Convertibility of Simple and Fully-Adjustable Split Keyboards 
     A key feature of the particular embodiment of the present invention illustrated in  FIG. 11B  is that the keying modules  22 L, 22 R readily attach via hinges to the respective base units  24 , 26 , using hinges that incorporate removable hinge pins  31  with an enlarged, easily-handled gripping features on one end. This construction allow for easy conversion back and forth between simple versions of the split keyboard  20  (in which the keying modules  22 L, 22 R do not tent) and fully-adjustable versions of the split keyboard  20  (such as that shown in  FIGS. 11A and 11B ). One particular embodiment of the removable hinge pin  31  has a crimped, looped end, which is inexpensive to fabricate and is easy to grip. 
     To convert the simple split keyboard  20  to a fully-adjustable model, the keying module  22 L, 22 R is oriented on the base with the two hinge  30  elements interdigitated. The removable hinge pin  31  is inserted into one end. After it is fully inserted, the gripping loop can be folded down to lock in place in a recess or other feature on underside of case. The first portion of the removable hinge pin  31  could anchor tightly at the end of travel if the channel in which it is inserted had a smaller diameter at the distal end. To convert the fully-adjustable model to the simple model, the gripping loop is lifted and the removable hinge pin  31  is removed. 
     Removable Palm Rests 
     Also surprising is that removable palm rests, when present, are supported with no additional action by the user. Previous designs with removable palm rests (Siemens KBPCE and Kinesis Maxim) required a separate and awkward adjustment step for the palm rests whenever a tenting angle was changed. In embodiments of the present invention, however, a longer lifting flange  36  is used when palm rests  32  are installed. However, even with a shorter lifting flange  34  designed for configurations where the palm rests  32  are removed but with palm rests and base extensions installed, acceptable sturdiness is achieved as long as the user does not support more than the normal weight of hands and arms on the palm rests. In fully-adjustable models, the lifting flanges  34 , 36  that support the keying modules  22 L, 22 R also support the palm rests  32  without requiring any special adjustment. 
     A removable base extension is typically provided with fully adjustable embodiments for use when palm rests are installed. When the palm rests  32  are used with the fully adjustable embodiment, an extended lifting flange  36  and base extension are provided to create a stable platform for supporting the palm rests. 
     Since lifting flanges  34 , 36  are typically different lengths depending on whether palm rests  32  are installed, it can reduce manufacturing and packaging costs if a single lifting flange can be converted from long to short. For this purpose, the flanges may be scored or otherwise adapted to facilitate shortening by bending and breaking off one end. In one embodiment, the lifting flange  36  incorporates a feature which allows a long version to be regenerated by clipping the end piece back onto the short lifter. This is feasible since the weight of the keying modules  22 L, 22 R would not stress this clip joint, being applied to the hinged portion of the lifter. 
     Electrical Connections to Left and Right Keying Modules 
     When the center of the split keyboard  20  is lifted (“tented”), the keying modules  22 L, 22 R will elevate from their hinges  30  and the medial edge of each module will move away from the centerline. In some embodiments, a flexible electrical connection extends between the two keying modules  22 L, 22 R. One such wired design which is also extensible is shown in  FIG. 8A  of the Provisional Application. Such a design was prototyped to provide a 5 inch separation between left and right keying modules (see Provisional Application,  FIGS. 9A-D ) and the cable extended and retracted easily. 
     An alternative to an extensible and retractable linking cable is an exposed linking cable (Provisional Application,  FIG. 10 ). In some embodiments it is desirable for the linking cable to be detachable by the user, to facilitate transport, storage, or repair. In another embodiment, each module could be equipped with its own separate keyboard electronic module, which could be linked via cable (e.g. USB) or wireless means to the computer.  FIGS. 8A-B  and  10  in the Provisional Application depict possible arrangements of circuit boards, connectors, and other electronic components. Any of these embodiments could incorporate a wireless connection using available technology used for other keyboards. 
     If a wired connection is used, the simplest electronic design can utilize a 14-to-16 wire cable to link the left matrix to the right matrix, without requiring any active electronic components. Such a cable could be detachable and replaceable using easy-to-operate connectors such as those used with PCMCIA devices (modems, network cards, e.g. Honda brand). However, for embodiments which add additional special key actions to the left side (see, e.g., Provisional Application,  FIG. 1B ), additional wires will be required in any linking cable. The Goldtouch keyboard uses approximately 25 wires in a linking cable and the present invention could do so as well. If a small diameter wire (e.g. 30 gauge) is used to reduce the outer diameter of the linking cable, which would be desirable if more than approximately 16 wires are required, detachability of the linking cable is a further benefit in case replacement is required due to a broken wire inside. 
     Wireless Split Keyboards 
     Wireless keyboards are well known in the art, for applications where the user does not wish to be tethered to the computer by a cable. In the present invention, because the split keying modules are smaller than a unified keyboard, and the electronics supporting wireless communication are typically somewhat more bulky than those communicating via a cable, and because on-board batteries are required, the main electronics module and the batteries are typically stored in different modules. For embodiments wherein the two keying modules are connected by a linking cable, said cable will require at least two additional wires (power and ground) to connect the batteries to the electronics. 
     However, one wireless embodiment of the invention can also eliminate the linking cable, by utilizing separate wireless control modules and battery compartments in each keying module. In such a fully-wireless embodiment, because both modules must be active at all times, this feature is not normally feasible due to latency as the computer recognizes and activates each module in turn. However, an unexpected capability of one commercial product, the Adesso 2.4 Ghz wireless keyboard and touchpad, has been demonstrated. In this example, two standard commercial units can communicate simultaneously with a single USB receiving unit. These keyboards have integrated wireless touchpads and remarkably, both keyboards and touchpads can communicate virtually simultaneously (with normal typing speeds on both keying modules) through a single receiving unit. While batteries would be required in each module, the linking cable typically weighs the same or more than the normal batteries, so that such a totally wireless embodiment may be lighter as well as more compact and more convenient to use than the embodiment which uses a linking cable. 
     Chair-Mounted Split Keyboards 
     Previous patents have described ergonomic keyboards attached in various ways to a chair. While not necessary for effective use, wireless embodiments of the present invention may be preferred for certain chair-mounted applications. The fully-wireless embodiment described above offers significant advantages in that the linking cable does not need to be routed behind and or under the seat back or pan. However, the wireless keyboard with linking cable offers an unexpected benefit, in that additional battery capacity may be stored under the seat pan and connected to the keyboard electronics via the linking cable. 
     In order to provide low-cost and flexible positioning, a split ergonomic keyboard has required two sets of attachment hardware that has proven expensive, difficult to adjust, and/or has lacked sturdiness. The versatile configurability of the present invention provides significant benefits for embodiments in which the split keyboard is mounted to a chair or to an under-desk track. To provide the important stability and resistance to rocking or bouncing which is important with a chair/track-mounted keyboard, the keyboard attachment arms can be fabricated as a hollow extrusion or clamshell assembly of injection molded plastic, or from hemmed or flanged steel 14 gauge or greater. 
     Chair-mounted embodiments of the present invention can be configured generally in three different ways which vary in their adjustability, and likewise in their cost and sophistication. A horizontally-adjustable embodiment utilizes the simple configuration (described above). The attachment arm is connected to underside of each keying module. Depending on the type of arm, attachment hardware may use a sliding, clip-on or bolt attachment mechanism to the chair (typically via the arms). If the chair arms have not been specially adapted, a specialized bracket designed to connect to the keyboard attachment arm may be installed on the chair (typically between the arm rest and arm pad). When the keyboard attachment arm is designed to slide on or clip to the chair, an easily-removable bolt (typically a thumbscrew) can be used to prevent accidental or inadvertent detachment of the keyboard attachment arm. In order to facilitate making a sturdy connection of the keying module to that attachment arm, an attachment may be utilized to facilitate a strong connection, the bottom of the keying model may be specially designed with screw bosses or one or more integrated bolts 
     Significant horizontal adjustability can be achieved even with the simple split keyboard attached to a chair if the attachment arms are slotted, and are attached to the keying module with a means to easily loosen and tighten the attachment, such as a knob and bolt. When the knob is loosened by the user, the keyboard may be rotated and/or slid proximally or distally relative to the user, in the horizontal plane. With a rotating arm rest provided on many office chairs, even greater adjustability may be achieved. If a palm rest is present, the attachment arm may be designed to support said palm rest. 
     A fully-adjustable embodiment of the invention utilizes the adjustable version of the keyboard (described above). The keying modules may be mounted to the arms of a chair using an attachment arm similar or identical to that described above and providing the same range of horizontal adjustability. However, since the adjustable version of the keyboard incorporates the ability to provide tenting, significantly greater adjustability is provided. This embodiment offers the unexpected benefit of providing easy access to the undersides of keying modules in order to change batteries without requiring that the keyboard be detached from the chair. 
     A maximally-adjustable embodiment may use a ball joint near the chair arm to which the attachment arm is connected. By temporarily loosening the ball joint, a user may tilt the keyboard modules in any direction. Either the simple or the adjustable version of the keyboard may be used to achieve full adjustability. An additional benefit over the highly-adjustable embodiment described above is that the keying modules can be positioned very close to the user&#39;s legs, since no base module is present upon which the keying modules are supported. 
     Track-Mounted Split Keyboards 
     Such embodiments as described for mounting split keyboards to a chair also may be employed for mounting to an underdesk track or arm. This may be accomplished using the same or similar hardware as described above for mounting to the arms of a chair. 
     Pointer Tray for Chair and Track-Mounted Keyboards 
     When keyboards are attached to chair arms or to an under-desk arm, a surface must be provided for using a pointing device (e.g. mouse, touchpad, or related device) unless a pointing device such as a touchpad or pointing stick (IBM trackpad) is integrated into one or both keying modules. Embodiments of the present invention employ a small, thin tray (hereafter termed “mouse tray”), typically 4×6 inches but ranging from approximately 3×5 to 5×7 inches, which includes its own attachment arm that can be clipped on or slide into either side of each keying module. 
     If it is desirable that the pointer surface maintain the same attitude as the keying module, the ball-joint version of attaching the keying modules to the chair arms may be used. 
     Special Electronic Features for Wireless Versions 
     A unique electronic feature applicable to wireless versions is the transient LED feature. Wireless keyboards previously have not supported LEDs in the keyboard for reporting the status of Numlock, Scroll Lock, Capslock, or Fn status because they would excessively drain the batteries required for operation of the keyboard: Traditionally wireless keyboards provided such LEDs on the receiver module attached to the computer. However, the advent of very small receiver “dongles,” long range wireless transmitters such as 2.4 Ghz and higher frequencies capable of transmitting 30 feet or more, and large screen monitors and televisions that might serve as distance monitors, have all combined to eliminate the status LEDs in wireless devices. However, the user still benefits from knowing the status of these LEDs for maximum productivity. 
     The present invention solves this dilemma by providing user selectable, transient activation of status LEDs. This can be accomplished by providing a dedicated “LED” key (for example near the LEDs), which activates the LEDs when pressed but deactivates them when released. Alternatively, a key may be used for this purpose in combination with the Fn key to reduce the possibility of accidental activation. 
     One of the major shortcomings of wireless devices is that they can behave poorly because of signal interference, or because of weak batteries. It can be very frustrating for users when problems arise and it is not easy to determine the cause. A novel use of the above-described transient LED feature is its use as a battery charge status indicator. This feature would not require any power when not in use, because it would be activated only when the LED key is pressed in combination with another key (e.g. Fn). If a battery charge (e.g. battery voltage) monitoring circuit is included in the electronics, its status may be transiently reported by illuminating one or more of the LEDs. For example, if 4 LEDs are present, all 4 would illuminate if the typical fresh-battery voltage of 1.59 is sensed. 3 LEDs might illuminate if the voltage is 1.4-1.5, and 2 LEDs might illuminate is the voltage had dropped to 1.3. 
     Key Layouts 
     A further important feature is the highly effective key layout, which retains familiarity (an important element is accomplishing acceptability), while reducing reaches and adding special editing keys to further enhance productivity. Without changing the well-known alphanumeric key layout, editing keys can be optimized so that they are easier to reach yet hard to touch accidentally. While the relative positions and functions of the peripheral keys may change depending on the operating system and the needs of typical software application, the basic principles include symmetrical right and left side, and a single vertical column of editing keys on the far right. 
     As illustrated in  FIG. 15 , embodiments of the present invention also can provide an over-sized, horizontal or vertical Delete key  58  adjacent to the Backspace key  60 . This arrangement is novel and highly effective, since the Delete key  58  and the Backspace key  60  are often used frequently during editing and are related to each other in their actions. (As depicted in  FIG. 14 , known prior art keyboards have a double-tall vertical Delete key, but it is not adjacent to backspace.) The prior art Insert key is located to the side of the horizontal Delete key or above (distal from) the vertical Delete key, or as an embedded action, thus isolating it from the other editing keys. Hitting the Insert key by accident can cause inadvertent over-typing and many computer users employ this key action less than the other editing and modifier keys. This layout of the six editing keys preserves the general left-to-right and top-to-bottom arrangement of editing keys with which computer users are familiar. 
     In order to accommodate the optimal positioning of heavily used editing keys and still provide full-size function keys for accurate and convenient typing, several seldom used actions can be embedded (that is, accessible only when an Fn key is used to activate a hidden layer). The right side can include top level F7-F12 plus PrintScreen and the oversize Delete key. Embedded actions can include seldom-used Insert, Scroll Lock, Num Lock, and Pause/Break. 
     Elongated Space Bars and Expanded Central Gap 
     A shortcoming of known prior split keyboards is that for some users, the Space Bars do not extend far enough towards the midline. As shown in  FIG. 16 , a novel way to provide an optional extended space bar is to extend a thin flange  62  medially from the normal edge of the space bar. (Notably,  FIG. 16  also shows an embodiment of the split keyboard that does not incorporate a liking plate.) 
     In some embodiments (e.g. Provisional Application,  FIGS. 1D ,  2 B,  2 C,  2 D), the medial edge or edges of the keying modules can be extended by the flange  62  to extend the Space Bar by an additional 0.2-0.4 inches (typically 0.3 inches), to meet the needs of these special users. Because most users type the Space bar mostly with the right thumb, such an extension is most important for the right Space bar. However, to maintain symmetry and to support the needs of left handed typists, many embodiments utilizing the extended Space Bar make both of them the same size and shape. This can also maintain a lower cost, and cost is an element that affects acceptability. 
     Such embodiments can provide additional benefits to the user because they increase the inherent gap between left and right keying modules, which in turn increases the straightness of the wrists even if a front opening angle is not selected, and reduces the magnitude of any front opening angle (and thus reduces the adaptation period) if a front opening angle is selected. However, the additional gap in the middle may be judged to negatively affect acceptability, so it is not included in all embodiments. 
     Familiar Editing Keys 
     An important factor in achieving acceptability and productivity with narrow and symmetrical keying modules is the unique arrangement of editing keys. These keys must appear familiar and conveniently placed for a user accustomed to either the traditional or “Natural-style” keyboard, and yet the arrangement must allow the narrowest possible design. 
     It is difficult to design a keyboard which is simultaneously narrow, with adjustable and nearly-symmetrical modules, and with fully accessible editing keys which are not positioned where they can be easily struck inadvertently. The sacrifice in size, placement, and isolation of editing keys is the typical major failing of previous keyboards which were designed to be only 14-16 inches wide and yet used the normal key spacing. However, the present invention accomplishes the objective of narrowness without sacrificing acceptability, accuracy, or productivity by applying the well-known “stepped keycap” in a novel way. In addition to the Capslock key on the left keying module, which is often stepped, many the keys on the right side of the right keying module, just to the left of the far edge editing keys are stepped. These normally include Backspace, Pipes/backslash, Enter, R-Shift, and R-Control. 
     For the embodiment of the right keying module which has full-size arrow keys which occupy the same row as the space bar, and full-size function keys arrayed at the top, the optimal step width is achieved by optimizing the widths of the Shift, Enter, Ctrl keys. If the step is excessively wide, the Shift key becomes excessively narrow. If the Shift key is excessively wide, the step becomes excessively narrow. An optimal step provides good tactile feedback to the user without requiring an unnecessarily long reach for the editing keys. 
     The Shift key in the preferred embodiment is substantially shorter than the Shift key of a typical traditional keyboard; however, it is substantially larger than the shift key of many so-called “small footprint” keyboards, which use a small shift key with no isolation from neighboring editing and modifier keys. The present invention also provides a larger tactile surface for the Shift key than some known ergonomic keyboards. 
     The effect of such down-stepping of the keycap is to physically isolate the right-most column of editing keys so that they are not accidentally depressed, but to visually maintain the traditional large size of the keys which are stepped. This feature is important for both productivity (accuracy) and for acceptability of the design. The actual widths of the raised and down-stepped portions of the former keys may be varied somewhat depending on the desired tradeoffs between narrowness, performance, and acceptance; but in general the stepped keycap should provide the largest possible contact surface without having so little stepped surface that the effective isolation of the key to the right is reduced. 
     An important feature of the novel application of keytop stepping is that by stepping a group of neighboring keys by the same amount, a smaller step distance can be effective which allows for the desirably larger contact surface of the keytops. It will be recognized that the exact width and depth of the stepping can be varied for different keyboard designs without losing the inherent benefit of physically isolating the key to the right of each stepped key. In the present invention, the width of the stepped down region should be at least 0.12-0.15 inches wider than the normal border of a non-stepped keycap, and most desirably 0.15-0.20 inches of horizontal stepped surface. 
     As noted in  FIG. 11 , the Goldtouch keyboard uses three equal stepped keys (Capslock, Right Cntrl, and Right Shift) but this design greatly reduces the contact surface of the Right Shift key compared to the traditional or Natural-style keyboard. Whereas a Natural-style keyboard has a right shift key with a contact surface 1.5 inches wide, the same surface on a Goldtouch keyboard is only 0.65 inches wide (a 57% reduction in contact surface). By contrast, embodiments of the present invention provide a Right Shift contact surface of at least 0.83 inches wide. 
     Special Editing Keys on the Left Side 
     Furthermore, because the left side of the keyboard is inherently narrower than the right side, the inclusion of at least three and up to 12 special editing keys (see Provisional Application,  FIG. 1B ), which are not normally present on a traditional keyboard, will increases productivity and maintains acceptability without increasing the overall width of the keyboard. 
     To achieve maximal acceptance, it is important that special software drivers are not required for the keyboard, even when it includes such special editing keys. Therefore embodiments of the present invention will provide keys which produce standard key codes recognized by the intended operating system, which codes are well know to one experienced in the art. 
     A unique feature which will provide a further productivity enhancement will allow the user to convert the left Space Bar to perform Backspace. This configuration can be activated by pressing a combination of the Fn plus the small, left side key legended similar to “Spce/Bkspc.” User acceptability will be maintained because the default setting will be the Space Bar action. 
     Embedded Key Actions 
     It is common in laptop computer design to “embed” certain key actions which are not commonly used. Such embedded keys may be accessed by pressing a special function key, often labeled “Fn” of “Fcn.” 
     Multi Modal (Tap and Hold) Fn Key 
     The “En” key on a keyboard with multiple layers of key actions is either a “shift” or “toggle” action. In the present invention, the Fn key can be multimodal, performing selectively in both ways. 
     Said Fn key may perform either as a “Shift” key (active only while pressed) or a toggle key (shown as Fn lock, requiring a tap to activate and another tap to inactivate). Embodiments of the present invention also use this approach to embed both the numeric keypad and well as the seldom-used Scroll lock, Pause/break, and Insert functions. While Insert is used more often than the latter two embedded function key actions, Insert is often hit by mistake when placed in an more accessible location, which results in significant typing errors as previously entered data may be erased by the introduction of new data. In most configurations, a toggle Fn key is preferred, however in embodiments where additional left side keys are present, both shift and toggle versions of the Fn key may be provided. 
     The column of editing keys on the right keying module can retain a very familiar arrangement, even though the keys are in a vertical column rather than a horizontal group of six keys as used in the Traditional and Natural-style keyboards. For languages which read from left to right, as in all those of the Americas, Europe, and much of the remainder of the world, reading the traditional “group of six” editing keys from left to right results in the same sequence as reading those editing keys of the present invention from top to bottom. This location of said editing keys can increase productivity and acceptance of the present invention, because they are located on the right side of the keyboard as with traditional keyboards, and because many laptop computers also use a vertical column including at least some of these editing keys in order to reduce the width of their keyboards. 
     Notwithstanding the discussion above, variations may be made in the actions and/or positioning of certain keys on the far left of the keyboard without significantly affecting the benefits of familiarity and efficiency of the design. 
     All of the above U.S. patents, U.S. patent application publications, U.S. Patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirety. 
     From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.