One-handed alphanumeric keyboard and method

Alphanumeric keyboards are described for use with one hand to enter data. Each keyboard includes a plurality of individually movable alphanumeric keys that are each assigned a different letter of the alphabet. The keys are positioned side-by-side in multiple rows such that when four fingers of one hand are positioned over a home position, these fingers can depress all the letters by moving less than three key positions from the home position. Specialized key features are provided on the keyboard to facilitate the execution of multi-key combinations. A right-hand keyboard and a left-hand keyboard are disclosed as interchangeable with a conventional keyboard in a supporting shell. Alternatively, both the right-hand and left-hand keyboards are supported on opposite sides of a common rotatable member pivotably mounted in the supporting shell.

BACKGROUND OF THE INVENTION 
The present invention relates to data entry keyboards and more particularly 
to manually activated keyboards for use with one hand, which minimize 
operator fatigue and maximize efficiency. 
In nearly every sector of business, work activities center around the use 
of computer and data entry systems. These systems incorporate electronic 
keyboards with the standard QWERTY key arrangement for data entry 
(referring to standard keyboards that contain the letters Q-W-E-R-T-Y 
beginning at the upper left end of the second row from the top). However, 
there is a large segment of our global society which is shut out of 
employment opportunities in fields which require the efficient use of 
standard keyboards for data entry--namely those who, for various reasons, 
only have the use of one hand. 
A number of one-handed keyboard designs have been proposed for various 
applications. Examples of these one-handed keyboard designs are disclosed 
in U.S. Pat. Nos. 4,042,777, 4,615,629, and 4,849,732. Many of the prior 
art one-handed designs require that two or more keys be depressed 
simultaneously to control the sequence of characters being generated; that 
is, to generate each letter of the alphabet, multiple keys must be 
depressed. 
Other keyboards, such as those disclosed in the U.S. Pat. No. 4,615,629, 
have each letter assigned to an individual key, with the keys spread 
across the keyboard. When the operator accesses the keys on such a 
keyboard, the operator's fingers do not depress these keys in a precise 
manner. In addition, because the alphanumeric keys are spread over the 
keyboard, the fingers must stretch to access the keys, resulting in the 
hand moving away from a home position. This hand movement is fatiguing and 
prevents rapid access of all of the letters. 
While some of these designs have merit in terms of improved ergonometric 
design and input efficiency, they do not meet the immediate need of 
providing a system which, while permitting one-handed operation, is easily 
learned with minimum intimidation by operators accustomed to standard 
QWERTY keyboard design. 
Therefore, the availability of a one-hand keyboard which maintains the 
physical arrangement of the current standard QWERTY configuration as much 
as possible while facilitating one-hand operation, would greatly benefit 
those who have previously learned or have some familiarity with two hand 
typing on the standard QWERTY keyboard and, either by choice or necessity, 
have need for one hand operation. This group includes those who have 
become disabled after learning standard typing techniques as well as those 
who would find advantage in the ability to type efficiently with one hand 
while having the other hand free, such as Computer Aided Design (CAD), 
Process Control, or Medical Diagnostic system operators who use keyboards 
in conjunction with digitizer pads, mouse systems, control devices, or 
sonographic/radiographic instruments. In addition to the needs of those 
having the use of only one hand, there exists another work place problem 
related to keyboards. The extended duration of manual data entry required 
by many work situations has resulted in "repetitive strain injuries" such 
as Carpal Tunnel Syndrome becoming one of the leading categories of work 
place injury. While neither the cause nor the cure for these major 
debilitating injuries has been identified, it seems apparent to this 
inventor that there is a high probability that a scenario common to many 
stress/strain injuries is at work here: 
1) The task and work situation is one which does not allow for interruption 
or delay on the part of the worker even when suggested by the pain and 
discomfort symptoms of physical strain. 
2) Typically, permanent injuries are avoidable if the activity causing the 
physical strain is discontinued for a reasonable time to allow fatigued 
muscles to rest and recover. 
3) What is a non-permanent strain injury becomes a permanent non-reversible 
injury when the activity causing the physical strain is continued far 
beyond the first symptoms of pain or discomfort. 
Therefore, the ability to continue data entry activities with one hand 
while resting the other hand and then changing hands when the first hand 
becomes fatigued would accomplish the requirements of continued work 
production while avoiding what is possibly the primary cause of repetitive 
strain injury--the condition of extended strain duration without rest. The 
present invention provides a form of full function data entry keyboard 
consisting of easily selectable left- and right-hand keyboard shells which 
accomplish the required hand-changing facility. 
SUMMARY OF THE INVENTION 
A principal object of this invention is to provide an improved method and 
apparatus for typing with one hand all the English alphabet characters, 
numbers, and commonly used grammatical symbols. 
It is another object of this invention to place letters on a keyboard in a 
position that minimizes the physical work effort expended in typing 
typical documents. 
Another object of this invention is to place alphanumeric keys on a 
keyboard in positions where each of the letters in the alphabet can be 
accessed by the hand in a single finger movement. 
A further object of this invention is to assign letters and symbols to keys 
on a keyboard based on standard frequency statistics for the English 
language to minimize work by the fingers to access the keys. 
An additional object of the invention is to place keys within the normal 
span of the human hand so that keyboard symbol access does not exceed more 
than five inches from the small finger to the first finger, thereby 
increasing productivity when typing with one hand. 
Another principal object of the invention is to provide a technique for 
simultaneous entry of multiple characters, thereby increasing control 
entry capability by a single hand. 
A further object of the invention is to position alpha characters on a 
keyboard so that a typist can extend his or her fingers on one hand less 
than three character positions from the home position and still access all 
the letters of the alphabet. 
An additional object of this invention is to provide a method of entering 
data with a keyboard using a single hand to minimize physical work effort 
when typing typical documents. 
Another principal object of the invention is to provide a manually 
activated full-function keyboard with a central one-hand shell that 
incorporates a method of easily changing from one version to the other 
version of the two basic one-hand keyboard designs. 
These and other objects are provided with a manually activated keyboard for 
use with either the right or left hand. The keyboard includes a plurality 
of individual manually movable alphanumeric keys, each operative to 
indicate a different letter of the alphabet when depressed. The keys are 
preferably positioned side by side on the keyboard in parallel juxtaposed 
rows such that when the fingers of the hand rest on the keys in the center 
of the rows, the fingers on one hand can depress all the alphanumeric keys 
by moving less than three key positions from the center row. By moving 
less than three key positions, the physical work effort exerted is 
minimized. 
In another embodiment of the invention a method for entering simultaneous 
key combinations employs the steps of depressing a multi-combination key 
on the keyboard and then depressing a sequence of keys on the keyboard 
after depressing the multi-combination key. The multi-combination key is 
then depressed a second time after the sequence of keys has been 
depressed. An indication that a simultaneous key combination has been 
depressed corresponding to the sequence of keys is provided when the 
multi-combination key is depressed for the second time. The 
multi-combination key then allows simultaneous key combinations to be 
provided simply and efficiently with one hand. 
Another form of the invention provides an enhancement in the operation of 
the previously described multi-combination key. In this arrangement, two 
key combinations are entered quickly by depressing a two-combination key 
on the keyboard and then depressing a two key sequence of keys after 
depressing the two-combination key. The selected combination of two keys 
is then simultaneously entered at the time the second key is selected 
without the need to depress the two-combination key a second time. The 
two-combination key allows the entry of two-key simultaneous combinations 
which would otherwise be beyond the span of a single hand on a standard 
101-key keyboard.

DETAILED DESCRIPTION 
1. The One-Hand Keyboard Arrangements 
Referring first to FIGS. 1 and 4, there is shown an optimized data entry 
keyboard 110 which, according to the present invention, is completely 
operational by a single human hand and includes all standard alphabetic, 
numeric, punctuation and function keys found on a standard two hand 
electronic data entry keyboard. 
The right-hand keyboard 110 includes a keyboard housing 112, and four rows 
of keys 114, 116, 118 and 120, with four of the keys 122, 123, 124 and 125 
serving as the home keys in row 114. In that regard, key 122 is the home 
key for the right index finger; key 123 is the home key for the right 
middle finger; key 124 is the home key for the right ring finger; and key 
125 is the home key for the right little finger. As shown in FIG. 4, the 
"shift" key 136 is easily operated by the right thumb. Keys 132-142 serve 
various conventional keyboard features which are indicated by legends on 
those keys (except key 137, which contains no legend and functions as a 
conventional "space bar"). 
The right-hand keyboard 110 also includes special function keys 144, 146, 
148 and 150, the purpose for which will be explained in greater detail 
below. 
It is thus seen that in the optimum right-hand keyboard 110, the home keys 
are formed respectively by the letters T-E-A-O. FIG. 3 is a finger stroke 
reference diagram, showing paths depicted by arrows indicating which 
fingers on the right hand are used to stroke each key, and with the 
encircled numerals 1 through 26 indicating arbitrary reference numbers 
used to identify key selection in Column 1 of Table 1. In accordance with 
the present invention, it will be understood that the fingers on the right 
hand can depress all of the alphanumeric keys in rows 114, 116, 118 and 
120 by moving less than three key positions from the center, home row 114, 
as depicted by the arrows in FIG. 3. 
There is also shown in FIGS. 2 and 5, an optimized left-hand keyboard 210 
mounted in a keyboard housing 212, and defining four rows 214, 216, 218 
and 220 in a manner similar to the right-hand keyboard 110 of FIG. 1. Home 
keys for the left-hand keyboard 210 are defined by keys 222-225. In this 
regard, key 222 functions as the home key for the left index finger; key 
223 serves as the home key for the left middle finger; key 224 serves as 
the home key for the left ring finger; and key 225 serves as the home key 
for the left little finger. Likewise, the "shift" key 236 if easily 
operated by the left thumb, as indicated by FIG. 5. 
In a manner similar to that shown with respect to the right-hand keyboard 
depicted in FIG. 3, the left-hand keyboard of FIGS. 2 and 5 likewise 
permits the fingers on the left hand to depress all of the alphanumeric 
keys in rows 214, 216, 218 and 220 by moving less than three key positions 
from the home keys 225 in the center home row 214. 
It will be further understood by comparing FIGS. 1, 3 and 4 with FIGS. 2 
and 5 that the left-hand keyboard 210 of FIG. 2 is essentially a "mirror 
image" of the right-hand keyboard 110 shown in FIG. 1, such that the same 
finger on the right hand depresses the same keys as the same finger on the 
left hand, with the same relative work effort being exerted by the same 
finger for the same key. It will further be appreciated by those skilled 
in the art that all keys remain within the normal span for a right or left 
hand as that of a standard, two-handed keyboard, which typically is about 
five inches from the little finger to the index finger. 
The manner in which the optimal position for each key on the keyboards 110 
and 210 is selected will now be described with reference to FIG. 3 and 
Table 1 set out below. Table 1 is used to determine the distance that the 
four fingers of either hand must travel from their assigned "home" 
position when selecting any other key, and is useful in assigning an 
ordered number sequence to the alphabetic keys based on the amount of work 
required for each finger to select a desired key. 
TABLE 1 
__________________________________________________________________________ 
MINIMUM WORK EFFORT KEY SEQUENCE 
OPTIMIZATION CALCULATION TABLE 
RELATIVE 
RELATIVE 
MINIMUM- 
PATH 
LATERAL 
VERTICAL 
FINGER WORK TO WORK KEY 
REF DISTANCE 
DISTANCE 
EFFORT SELECT KEY 
SEQUENCE 
(1) (2) (3) (4) (5) (6) 
__________________________________________________________________________ 
1-1 0.000 0.100 1.00 0.100 1 
1-5 0.839 0.100 1.00 0.939 8 
1-6 0.839 0.100 1.00 0.939 7 
1-7 1.352 0.100 1.00 1.452 12 
1-8 0.750 0.100 1.00 0.850 5 
1-9 1.500 0.100 1.00 1.600 13 
1-10 
1.250 0.100 1.00 1.350 11 
1-11 
0.791 0.100 1.00 0.891 6 
1-12 
2.035 0.100 1.00 2.135 22 
1-13 
1.625 0.100 1.00 1.725 16 
1-14 
1.505 0.100 1.00 1.605 14 
2-2 0.000 0.100 1.33 0.133 2 
2-15 
0.839 0.100 1.33 1.249 10 
2-16 
0.791 0.100 1.33 1.185 9 
2-17 
1.505 0.100 1.33 2.135 23 
3-3 0.000 0.100 2.00 0.200 3 
3-18 
0.839 0.100 2.00 1.878 19 
3-19 
0.791 0.100 2.00 1.782 17 
3-20 
1.505 0.100 2.00 3.210 24 
4-4 0.000 0.100 2.00 0.200 4 
4-21 
0.839 0.100 2.00 1.878 20 
4-22 
0.750 0.100 2.00 1.700 15 
4-23 
0.791 0.100 2.00 1.782 18 
4-24 
0.901 0.100 2.00 2.002 21 
4-25 
1.505 0.100 2.00 3.210 25 
4-26 
0.737 0.100 2.00 3.674 26 
TOTAL RELATIVE WORK - ALL KEYS (7): 
39.804 
__________________________________________________________________________ 
In Table 1, Column 1 is designated "Path Ref" and refers to the finger 
stroke paths depicted in FIG. 3 for finger movements relative to the home 
keys 122-125 for keyboard 110 and keys 222-225 for keyboard 210 (see FIG. 
3). Column 2 of Table 1 refers to the "Lateral Distance" and indicates the 
distance travelled horizontally between each "home" key 122-125 or 222-225 
and another selected key for each finger movement. Column 3 of Table 1 is 
the "Vertical Distance", and indicates the vertical movement component of 
the key when depressed. Column 4 of Table 1 indicates the "Relative 
Strength", indicating the results of tests which were conducted to obtain 
the relative strength on each of the four fingers needed to depress a key. 
Those measured results for typical individuals are: 
______________________________________ 
Finger Relative Strength 
______________________________________ 
Index 1.00 
Middle 0.75 
Ring 0.50 
Little 0.50 
______________________________________ 
Continuing, Column 5 of Table 1 indicates the "Relative Work to Select Key" 
and is the product of the relative finger effort of Column 4 times the sum 
of the vertical and lateral distances tabulated in Columns 2 and 3, 
respectively. Column 6 indicates the "Minimum Work Key Sequence" as an 
ordered arrangement of each key in terms of the relative work to select 
each key. The higher the sequence number, the higher the work effort 
required to select that key. Finally, the bottom entry as number 7 in 
Table 1 indicates the "Total Relative Work" which is the sum of the work 
effort for all of the keys, and indicates a measure of keyboard work 
efficiency which can be used to select optimum home key locations and 
key-to-finger assignments. By way of example, shifting the four finger 
home keys one key to the left results in a total relative work of 40.108, 
which is higher than the total relative work of 39.804 given in Table 1. 
It will therefore be understood that, using the analysis set out in FIG. 3 
and Table 1, the optimum numbering sequence for the right-hand keyboard is 
shown in FIG. 4 and the left-hand keyboard in FIG. 5. The data in Column 6 
of Table 1 is then used to assign alphabet letters to keys based on the 
frequency of occurrence of each letter in the English language. 
Referring now to Table 2 set out on page 16, there is shown the relative 
frequency of occurrence for letters in the English language. Using this 
data, the letters of the alphabet are arranged on the keys by assigning 
the highest frequency letters to the lowest work effort keys as determined 
in Table 1. Thus, the letter "E" is assigned to key 123, the letter "T" is 
assigned to key 122, the letter "A" is assigned to key 124 and the letter 
"O" is assigned to key 125. This arrangement continues in descending order 
of frequency, with the key for the letter "Z" appearing in the location 
indicated by the encircled numeral 26 in FIG. 3. 
Of course, there remains the task of assigning numerals and grammatic 
symbols to the keys as well. As indicated for the right-hand keyboard 110 
in FIG. 6 and the left-hand keyboard 210 in FIG. 7, Arabic numerals are 
assigned to keys by the indicated number with the prefix "N". The 32 
grammatic symbols are assigned to keys utilizing Table 3. 
TABLE 2 
______________________________________ 
RELATIVE FREQUENCY OF LETTERS 
IN THE ENGLISH ALPHABET 
DESCENDING 
ORDER OF 
LETTER FREQUENCY 
______________________________________ 
e 1 
t 2 
a 3 
o 4 
n 5 
r 6 
i 7 
s 8 
h 9 
d 10 
l 11 
f 12 
c 13 
m 14 
u 15 
g 16 
y 17 
p 18 
w 19 
b 20 
v 21 
k 22 
x 23 
j 24 
q 25 
z 26 
______________________________________ 
TABLE 3 
______________________________________ 
RELATIVE FREQUENCY OF SYMBOLS.sup.1 
DESCENDING DESCENDING 
ORDER OF ORDER OF 
SYMBOL FREQUENCY SYMBOL FREQUENCY 
______________________________________ 
` 1 * 17 
.multidot. 
2 & 18 
; 3 = 19 
: 4 @ 20 
? 5 + 21 
6 [ 22 
/ 7 ] 23 
" 8 &lt; 24 
' 9 &gt; 25 
( 10 { 26 
) 11 } 27 
$ 12 28 
- 13 .about. 29 
! 14 
##STR1## 30 
% 15 
##STR2## 31 
# 16 ` 32 
______________________________________ 
.sup.1 Frequency order based on inventor's survey and on layout of typica 
keyboards for personal computers.? 
Referring again to FIGS. 6 and 7 with reference to Table 3, it is seen that 
the various entries of Table 3 are reflected by encircled reference 
numerals indicated in each of FIGS. 6 and 7. By way of example, the "," 
symbol has the highest order of frequency, and is therefore assigned to 
key 123; the "." symbol has the second highest order of frequency, and is 
assigned to key 124; the ";" symbol has the third highest order of 
frequency, and is assigned to key 125; and so forth, as reflected in Table 
3 and depicted in FIGS. 6 and 7. The keyboards 110 and 210 resulting from 
the analysis of FIGS. 3 and 6 (right-hand keyboard) and FIG. 7 (left-hand 
keyboard) together with Tables 1, 2 and 3 are depicted in FIGS. 8 and 9, 
respectively, and represent one optimal arrangement for the alphabetic, 
numeric and symbol keys for a one-hand keyboard. However, there are other 
features associated with the keyboards 110 and 210 which may justify a 
further optimization of the keyboard arrangement, and which will be 
discussed in greater detail below. 
2. Special Function KEYSWITCH and SHFT-KEYSWITCH Keys 
Referring again to FIGS. 1 and 2, two special keys labelled KEYSWITCH and 
SHFT-KEYSWITCH, respectively, are provided for each of the keyboards 110 
and 210. For the right-hand keyboard 110 of FIG. 1, the KEYSWITCH is 
designated by reference numeral 148, and the SHFT-KEYSWITCH is designated 
by reference numeral 150; the similar keys on the left-hand keyboard 210 
of FIG. 2 are designated by reference numerals 248 and 250, respectively. 
These keys are provided to enable the use of a single key to generate 
numeric or symbol characters in addition to the alphabetic characters 
assigned to a selected key. This multi-use capability is accomplished in 
the present invention by the addition of these keys 148, 150 and 248, 250 
in a manner similar to the standard shift key of a conventional QWERTY 
keyboard, but are in addition to the standard shift key and are located in 
a position easily accessible by the thumb of each corresponding hand. By 
using the thumb to depress these keys in conjunction with other keys, 
multiple-character use of a selected key can be obtained. 
3. Special Function SINGLE KEY HOLD and MULTI-KEY HOLD Keys 
In addition to the multi-character key functions of keys 148, 150 and 248, 
250 described in Section 2 above, the one-handed keyboards of the present 
invention are provided with additional enhancements to further facilitate 
efficient one-handed operation. These features are added to accommodate 
the simultaneous character input combinations required by some computer 
word processing and applications software. 
Referring now to FIGS. 1 and 2, the present invention contemplates three 
types of key combination inputs: 
a) Dual-function (e.g., SHFT-TAB) key 134 and dual prefix (e.g., CTRL-SHFT, 
SHFT-ALT) keys 142, 138 within the main shell 112 which generate the 
indicated two-key sequence with a single keystroke. 
b) Special single character hold-down key 144 (labeled SINGLE KEY HOLD/AUTO 
REL in FIG. 1)--depressing this key, followed by any other two-key 
sequence, results in the simultaneous transmittal of the selected two-key 
combination at the moment the second character key is depressed. 
c) Special multiple character hold-down key (labeled MULTI KEY HOLD/MAN REL 
in FIG. 1) with manual release of any selected multiple-key combination 
when this special hold-down key is depressed a second time. 
Thus, in accordance with the present invention, keys 144 and 146 facilitate 
the efficient one-hand operation of the keyboard 110 (and likewise 
keyboard 210 of FIG. 2) by accommodating multiple-character input 
combinations as required by some computer application software. The single 
character hold down key 144 provides automatic release of any selected 
two-key combination when the second of the two-key combination keys is 
depressed. The single-key 146 provides manual release of any selected 
multi-key combination when this special hold down key is depressed a 
second time. 
Referring now to FIG. 12, it is clear that these special function keys 144, 
146, 148 and 150 of keyboard 110 (and the corresponding keys for 
left-handed keyboard 210) are particularly useful when the basic one-hand 
keyboard 110 or 210 is included as the alphanumeric portion of a typical 
"101 key" keyboard, as is used with computers today. For example, it would 
heretofore be extremely awkward or impossible to generate the sequence 
"CTRL-SHFT-F12" with one hand on a standard keyboard, because of the 
physical separation of those keys. In the present invention, this sequence 
is easily accomplished with the three-stroke sequence "SINGLE KEY 
HOLD/AUTO REL . . . CTRL-SHFT . . . F12" (the left-hand keyboard is 
similarly depicted in FIG. 13). 
Referring now to FIG. 16, there is shown one example of a flow chart 
executed by logic circuitry within the keyboard to provide the single-key 
hold/manual release function of key 146. In algorithm module step 160, the 
keyboard senses whether or not the single-key hold/manual release key 146 
(or the corresponding key 246) has been depressed. If depressed, the 
keyboard disables the register output as shown by step 16b, and waits for 
another key to be depressed, as represented by step 162. 
As an output from step 164, the keyboard 110 stores the character 
corresponding to the alphabet key that was depressed as step 162, and the 
keyboard waits for a second alphabet character key to be depressed, as 
represented by step 168, after which that character is also added to the 
register storage as indicated by step 170. Simultaneously, the step 170 
enables the register output as indicated by step 172, enabling an output 
from the storage register 174 as a two character output combination, 
represented by step 176. 
FIG. 17 is a flow chart depicting the electronic sequence for use with 
multi-key 146 for keyboard 110, and multi-key 246 for keyboard 210. Prior 
to depressing the multi-key 146, counter N is at its normal "0" state. The 
sequence is initiated by depression of one of the multi-keys, as indicated 
by step 180 and counter N is simultaneously incremented by 1. If counter 
is less than or equal to 1, then the register output is disabled as the 
keyboard waits for the next series of character keys to be depressed. 
Thereafter, each character depressed is indicated by an output to the 
storage register 186, including outputs 190, 191 and 192. Following 
depression of the last desired character keys, the multi-key 146 is 
depressed a second time and counter N is incremented by 1. Decision module 
182 now detects that counter N is greater than 1 and subsequently the 
output register is enabled and the counter N is reset to "0" as indicated 
in step 184. This permits an output from storage register 186 as indicated 
by the combination output 194. 
4. Final Preferred Arrangement of Keyboards 110, 210 
A final preferred arrangement of the keys for keyboard 110 and 210 will be 
described with reference to FIGS. 10 and 11, and which additional 
consideration is given to the arrangement of the keys to minimize the 
probability of successive finger strikes by the same finger, based on 
standard lists of common two-letter combinations. Additionally, customary 
paired symbol groups have been located adjacent to each other on the final 
preferred arrangement of keys shown in FIGS. 10 and 11. In each case, the 
choice of key location involves the evaluation of finger movement work 
effort and selections made to minimize total work effort and to minimize 
consecutive finger strikes by the same finger for the final keyboard 
arrangement. It will of course be understood by comparison of FIGS. 10 and 
11 that the same keyboard layout is illustrated in FIGS. 1 and 2. 
Referring now to FIG. 15, it will be appreciated by those skilled in the 
art that the right-hand keyboard 110 and the left-hand keyboard 210 may be 
easily interchanged in a modular manner with a conventional QWERTY 
two-handed keyboard 310, for insertion with a keyboard shell 300, and may 
be adapted for conventional interconnection schemes found in such keyboard 
shells. 
5. Rotatable Keyboard System for Right-Hand and Left-Hand Keyboards 
Another feature of the present invention will now be described with 
reference to FIGS. 18 and 19, which illustrate a rotatable keyboard system 
which permits easy selection of a one-hand keyboard for use with either 
the right or left hand. The keyboard system 410 includes a shell 412 
having a central opening defined by inner surfaces 414, 415, 416 and 417, 
which are disposed in a generally rectangular configuration. A keyboard 
support 418 is mounted in the opening defined by the surfaces 414-417 via 
a pivot 424 at each side of the keyboard support. The keyboard support 418 
has opposing first and second surfaces 426 and 428. A right-hand keyboard 
110 in accordance with the discussion set out above and as illustrated in 
FIG. 1 is disposed in the first surface 426, and a left-hand keyboard 210 
is disposed in the second surface 428. As shown in FIG. 19, the keyboard 
support 418 is easily rotated through an arc 430 to permit the selection 
of either a right-hand keyboard 110 or a left-hand keyboard 210. While a 
one-hand keyboard (for either the right or left hand) has particular 
utility for disabled persons with only one hand, ready access to either a 
right- or left-hand keyboard in accordance with the arrangement shown in 
FIGS. 18 and 19 will permit a person having a capacity to use both hands 
the opportunity to avoid the fatigue and stresses which often lead to 
permanent injuries, for example the well-known Carpal-Tunnel Syndrome. 
SUMMARY 
It will thus be understood from the above description that the one-handed 
keyboard arrangements provide the following features: 
a) Individual, manually operable keys, 5 rows of standard keys, character 
keys having nominal 0.75" center spacing in both horizontal and vertical 
directions, alternating 6 and 7 keys in juxtaposed rows from the bottom to 
top. 
b) The maximum distance of the center of any alphabetic key from the center 
of any home key being less than about two inches. 
c) Twenty-six alphabet keys which also include ten numbers and thirty-two 
symbols which are utilized in conjunction with the special KEYSWITCH and 
SHFT-KEYSWITCH control keys. 
d) Special SINGLE KEY HOLD/AUTO RELEASE and MULTI-KEY HOLD/MANUAL RELEASE 
function keys and a process for their use in generating multiple character 
combinations with one hand. 
e) Two keyboard layouts which include all functions of the standard "101 
KEY" keyboards now commonly in use, but which incorporate the left and 
right one-hand shell, respectively, of the present invention in place of 
the standard two-hand alphanumeric/symbol shell of the standard "101 KEY" 
keyboard. 
f) A modular keyboard layout which allows choice of left-hand, right-hand, 
or standard shells which are insertable into the otherwise standard "101 
KEY" keyboard arrangement. 
g) The processes described for using the above keyboard layouts to make 
possible one-hand input of typical documents and data with speed and 
efficiency equal to that of a two-handed person using a conventional 
keyboard such as might be found with computer systems today. 
h) A rotatable keyboard system permitting easy selection of either a 
right-hand or left-hand keyboard. 
This concludes the description of the preferred embodiments. A reading by 
those skilled in the art will bring to mind various changes without 
departing from the spirit and scope of the invention. It is intended, 
however, that the invention only be limited by the following appended 
claims.