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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to data entry keyboards, and more
specifically to an adjustable keyboard with adjustable divided key fields
synchronized by a synchronous gearing mechanism.
2. Art Background
Since the advent of the "standard keyboard" employed in ordinary
typewriters, various modifications have been made to simplify the
mechanics and improve the human factors of keyboard use. Such
modifications have included altering either the arrangement of keys or
changing the overall structural design, or both. For example, in German
laid-open description No. 27 25 677 to Muther, entitled "Tastatur fuer
Schreibmaschinen (Typewriter Keyboard)", an alternative arrangement of key
order and placement is disclosed wherein improved typing speed can be
achieved by placing the most frequently struck keys at the "home" position
for the eight typing fingers. The keyboard of Muther is a unitary key
field distributed in a fixed base, where the keys are arranged in
wave-like rows.
In U.S. Pat. No. 4,597,681 to Hodges, entitled "Adjustable Keyboard", a
keyboard arrangement is disclosed wherein two sets of keys can be pivoted
and tilted, as well as having adjustable keycaps to achieve a comfortable
typing position for a user. In Hodges, the sets of keys are contained
within two hingeably attached baseplates positioned within an underlying
support plate. However, the sets of keys in the Hodges keyboard must be
separately adjusted in both the pivoting and tilting dimensions, and the
complex construction of the adjustable keycaps can significantly increase
the cost of manufacture of the keyboard.
In U.S. Pat. No. 5,067,834 to Szmanda et al., entitled "Input Keyboard
Apparatus for Information Processing Device and Other Keyboard Devices",
an adjustable keyboard is disclosed wherein two sets of keys can be
pivoted and tilted to a comfortable position for the user. In Szmanda, a
universal pivot point and a pair of telescoping members are used to
articulate and support the keyboard arrangement in a desired position. As
in the Hodges patent, the sets of keys in the Szmanda keyboard must be
separately adjusted in both the pivoting and tilting dimensions.
Due to the nature of the articulating and adjusting hardware components
used in recent "improved" keyboard designs, such keyboards may be less
attractive to users from both cost and convenience considerations.
Depending upon the working height of the keyboard, as the key fields of
the articulating keyboards of Hodges and Szmanda become substantially
elevated above the work surface, a user may experience discomfort if the
palms and forearms of the user are not supported.
Moreover, existing adjustable keyboards comprising two key fields treat the
space bar in one of two ways. First, the space bar may be "split" into two
portions as taught by Hodges, with each key field containing one of the
two space bar portions. Second, an elongated, full-sized space bar fixed
relative to one of the key fields is used, and remains fixed relative to
one of the key fields comprising the keyboard, generally the right key
field, as the keyboard components are repositioned. The foregoing space
bar arrangements can produce undesirable results. For example, an open
space, or gap, will be created in the region between the separated key
fields normally occupied by a "standard space bar when the articulating
keyboard is adjusted outward, the gap occurring in the region where the
space bar is most commonly struck by a user's thumb. Further, two
separated key fields using the two-portion split space bar may also cause
the user to become disoriented as to hand or key position. Alternatively,
in arrangements using an elongated space bar fixed relative to one of the
key fields, the space bar will create an awkward extension when the key
fields are articulated outward during use.
As will be described in more detail in the following detailed description,
the present invention facilitates a comfortable and easy to use integrated
keyboard arrangement comprising a space bar which remains generally
centrally disposed between two articulating key fields, which keyboard may
be used with data entry or computing devices. Further, the present
invention provides for synchronizing means including a synchronizing gear
to permit synchronized or complimentary motion between the movable
component parts, thereby permitting easy positioning of the separate key
fields in an efficient manner relative to the stationary space bar. The
synchronizing gear allows transmission of force in only one direction of
gear rotation, enabling a gear tooth to be significantly thicker than a
prior art gear tooth, and therefore stronger and more reliable.
SUMMARY OF THE INVENTION
An integrated adjustable data entry keyboard provides more comfort and ease
of use for typists and users of computer or data entry systems. A divided
keyboard arrangement comprising a first key field and a second key field
are pivotably mounted upon a stationary base about a pair of pivot axes.
The first and second key fields substantially comprise a keyboard
arrangement, and permit adjustment of the keyboard according to a user's
preference. A space bar is separately attached to the base and occupies a
lower keyboard region centrally disposed between the first and second key
fields. The space bar is enlarged so as to remain within the radius of a
user's thumb's "strike zone" when a user adjusts the first and second key
fields, without creating the gap inherent in the prior art devices. A
synchronizing means comprising a synchronizing gear embodies a gear
profile allowing transmission of force in only one direction of gear
rotation, and with a limited range of rotation.
The present gear comprises a modified, asymmetric gear tooth profile,
including a pair of teeth having contact faces which are true involutes to
prevent speed oscillations across the range of gear motion. By repeating
the profiles around the gear minor diameter at large intervals, and by
reversing and stacking the gear profiles coaxially, the gearing mechanism
is capable of transmitting torque bidirectionally. The synchronizing gear
enables a gear tooth to be significantly thicker than a prior art gear
tooth, and therefore stronger and more reliable. The synchronizing means
may be employed to ensure complimentary orientation of the first key field
relative to the second key field, and thereby relative to the user's hand
position, even if the user pivots only one of the individual key fields.
Detachable palm rests comprising a compliant attachment means may be
attached to each of the first and second key fields to provide
substantially integrated palm and hand support for the user, thereby
increasing the user's comfort.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects, features and advantages of the present invention will be
apparent from the following detailed description with references to the
drawings, in which:
FIG. 1 is a perspective view of an integrated adjustable keyboard
comprising first and second key fields according to the present invention,
arranged in a first, closed position.
FIG. 2 is a perspective view of the integrated adjustable keyboard shown in
FIG. 1, illustrating the first and second key fields of the keyboard
adjusted to a second, open position.
FIG. 3 is a partially broken bottom plan view of the keyboard shown in
FIGS. 1 and 2, wherein a synchronous coupling means comprising a
synchronous gearing mechanism in accordance with one embodiment of the
present invention.
FIG. 4 is a perspective view of a high strength, limited rotation gear
design in accordance with the present invention.
FIG. 5 is a top plan view of the gear in FIG. 4, illustrating a comparison
between the present improved gear profile and a traditional gear profile.
FIG. 6 is a top plan view of a gearing mechanism using a pair of high
strength gears in accordance with the present invention illustrating the
single torque transmission direction.
FIG. 7 is a perspective view of a bidirectional interchangeable gear design
in accordance with the present invention.
FIG. 8a is an elevational view of a synchronous gearing mechanism in
accordance with the present invention.
FIG. 8b is an elevational view of the synchronous gearing mechanism of FIG.
8a as seen from the opposite planar side from that shown in FIG. 8a.
FIG. 9 is an enlarged view of the synchronous gearing mechanism of the
present invention.
FIG. 10 is a bottom plan x-ray view of an alternative embodiment of the
present invention, wherein the synchronous coupling means comprises a
linkage system.
FIG. 11A is a perspective view of an alternative embodiment of the present
invention, comprising compliantly attached palm rests coupled to the first
and second key fields, wherein the key fields are in a first, closed
position.
FIG. 11B is a perspective view of the embodiment shown in FIG. 11A, wherein
the key fields and palm rests are in a second, open position.
DETAILED DESCRIPTION OF THE INVENTION
An adjustable keyboard to facilitate comfort and ease of use in data entry
and computing devices is disclosed. In the following description, for
purposes of explanation, specific numbers, materials, and configurations
are set forth in order to provide a thorough understanding of the present
invention. However, it will be apparent to one skilled in the art that the
present invention may be practiced without these specific details. In
other instances, well known systems are shown in diagrammatical or block
diagram form in order not to obscure the present invention unnecessarily.
Referring now to FIG. 1, a perspective view of an adjustable keyboard 10
designed in accordance with the the present invention is shown. In FIG. 1,
keyboard 10 includes a first half 12 which supports a first key field 14
(shown more clearly in FIG. 2), and a second half 16 which supports a
second key field 18 (also shown more clearly in FIG. 2), which key fields
14 and 18 are shown in a first, closed position. First half 12 and second
half 16 are pivotably mounted upon a base 20 by a pair of pins (not shown
in FIGS. 1-2, reference numbers 8 and 9 in FIG. 3). Pins 8 and 9 are
coupled to the first and second halves 12 and 16 at laterally adjacent
upper corners, as shown in FIG. 3. First key field 14 and second key field
18 together substantially comprise a standard keyboard arrangement of keys
found in a traditional typewriter or computer keyboard. Moreover, first
half 12 and second half 16 are movably joined together by a synchronous
coupling means comprising a synchronous gearing mechanism 24 (FIG. 3)
described in further detail below and forming the subject matter of the
above-referenced co-pending application hereto, Ser. No. 07/782,004,
entitled, "Synchronous Gearing Mechanism with High Strength, Limited
Rotation Gear Profile," by David Nguyen and Dexter Francis.
A space bar 22 is separately positioned within base 20 in a substantially
standard keyboard configuration and remains stationary and proportionally
positioned between key fields 14 and 18 when key fields 14 and 18 are
adjusted relative to the base 20. Space bar 22 is aided in remaining
proportionally positioned between key fields 14 and 18 by the
above-referenced synchronous gearing mechanism 24, and will be further
described below. Space bar 22 is a generally rectangularly shaped keycap
with orthogonal top, left, and right edges, and having a sloped bottom
edge incorporating an appropriate radius 23. The radius 23 may be chosen
so as to nominally position a user's thumb consistently within easy
striking distance, i.e., the "strike zone", of space bar 22. Note that
unlike other prior art arrangements which follow the convention that the
space bar be struck only by the user's right thumb, thereby leading to an
offset space bar biased to the right side of the keyboard, the present
invention enables a user to equally well use either his right or left
thumb to strike space bar 22, at the user's preference.
Referring now to FIG. 2, shown is a reverse angle perspective view of the
adjustable keyboard of FIG. 1, with key fields 14 and 18 adjusted to a
second, open operational position. As shown, first half 12 and second half
16 have been pivoted outward, away from space bar 22, space bar 22
remaining centrally disposed in a standard keyboard position. Both first
half 12 and second half 16 have been rotated a substantially identical
amount with respect to base 20 due to the above-referenced synchronous
coupling means, implemented as synchronous gearing mechanism 24. As can be
seen by reference to the FIG. 2, key fields 14 and 18 have been moved into
what is believed to be a more comfortable typing position, wherein a
user's hands and wrists are not urged into the more cramped position
associated with traditional keyboards. Additionally, space bar 22 remains
in a convenient position and eliminates the unwanted gaps characteristic
of prior art solutions.
Referring now to FIG. 3, shown is a partially broken bottom plan view of
the adjustable keyboard of FIG. 1. As shown in FIG. 3, first half 12 and
second half 16 extend laterally beyond the border of base 20 and are
coupled to the base by synchronous gearing mechanism 24. As indicated
above, synchronous gearing mechanism 24 is described in detail in the
above-referenced co-pending parent application and will only be briefly
described here. For reference convenience and to facilitate a better
understanding of the present invention, reference numerals that are common
to the above-entitled co-pending application will be used to indicate the
component parts of mechanism 24 in the present application. Synchronous
gearing mechanism 24 is essentially a synchronous coupling means for
rotatably securing key field 14 and key field 18, carried by half 12 and
half 16, respectively, to base 20. Mechanism 24 comprises a bidirectional
gearing mechanism 60 which includes substantially identical bidirectional
gears 62 and 64. Gear 62 is fixedly secured to or integrally formed with a
moment element 90 which extends radially outward from a central axis 63 of
the gear, and gear 64 is fixedly secured to or integrally formed with
moment element 92 which extends radially outward from a central axis 65 of
the gear. As described in detail in the co-pending application, the teeth
of bidirectional gears 62 and 64 are meshed together, and each gear is
rotatably secured to base 20 at its respective central axis. This enables
each of the moment elements to rotate in a clockwise or counter-clockwise
direction in essentially synchronous motion relative to one another.
As shown in FIG. 3, first half 12 is coupled to moment element 92 through a
first aperture 30 in base 20 by a first connecting means 32. In one
embodiment, connecting means 32 is a post which is integrally formed with
first half 12 and is securely coupled to element 92 through an aperture
100 in the element. A second connecting means 34 also couples first half
12 to element 92 through a second aperture 36 in base 20. As presently
embodied, connecting means 34 is a post which is integrally formed with
first half 12 and is securely coupled to element 92 through an aperture 98
in the element. In a substantially similar configuration, second half 16
is coupled to moment element 90 through a third aperture 38 in base 20 by
a third connecting means 40. A fourth connecting means 42 also couples
second half 16 to element 90 through a fourth aperture 44 in base 20. In
the preferred embodiment, third connecting means 40 and fourth connecting
means 42 are integrally formed with second half 16 and are securely
coupled to element 90 through apertures 96 and 94 in the element,
respectively.
In normal operation of the integrated adjustable keyboard shown in FIGS.
1-3, a user will physically rotate either first half 12, second half 16,
or both halves at the same time. For purposes of illustration, we will
assume that the user rotates first half 12 in the direction indicated by
reference arrow 102, that is, outward from base 20 and into the desired
typing position. As will be described in detail below, rotation of first
half 12 will cause second half 16 to complimentarily rotate outward from
the base a substantially identical amount. The complimentary rotation of
first and second halves 12 and 16 ensures that the angle bisector of the
first and second halves comprising keyboard 10 will always point
substantially towards the user, regardless of the total angle subtended
between the key fields 14 and 18 due to the rotation selected by the user.
Complimentary rotation also ensures that the total angle is adjusted
symmetrically even though the user may physically rotate only one of the
key fields 14 or 18, thus further ensuring a bilaterally comfortable
typing position. In addition, because the angle subtended between first
and second halves 12 and 14 is symmetrically maintained between the halves
and base 20, the key fields 14 and 18 are thereby urged into symmetrical
position relative to space bar 22 mounted to base 20.
When the user rotates first half 12 as described above, moment element 92
is rotated a corresponding amount due to the coupling of the element to
half 12 by coupling means 32 and 34. Coupling means 32 and 34 are capable
of moving only within the limited range defined by the borders of
apertures 30 and 36, respectively. Thus, the confines of these apertures
(and those of apertures 38 and 44) define the minimum and maximum range of
available motion of first half 12 and second half 16. This has an
important advantage of keeping synchronous gearing mechanism 24 within its
limited range of operability, and helping to define what is believed to be
the nominal range of positions a user would likely find comfortable when
positioning key fields 14 and 18. As moment element 92 rotates in the
direction of arrow 102, gear 64 is caused to rotate in a counter-clockwise
direction. This rotation causes tooth 82 to transmit a torque to gear 62
via tooth 76, thus causing synchronized rotation of gear 62 in a clockwise
direction. This clockwise rotation of gear 62 causes moment element 90 to
rotate in a clockwise direction. As a result of the coupling between
second half 16 and element 90 by coupling means 40 and 42, clockwise
rotation of element 90 causes half 16 to rotate outward in the direction
of reference arrow 104. Additionally, because the teeth of gears 62 and 64
are meshed, and each gear is secured to base 20 coaxially with respect to
its central axis, second half 16 is rotated a substantially identical
distance relative to first half 12. Of course, if a user physically
rotates second half 16, the same principle as described above would cause
first half 12 to rotate a substantially identical distance. This is a
result of synchronous gearing mechanism 24 which functionally couples the
first and second halves together such that motion of either half in either
direction will cause the other half to reposition in a substantially
identical manner.
With reference to FIGS. 4-9 collectively, specific elements and features of
gears 62 and 64, together with distinctions and advantages over prior art
gear systems, will be described. Referring now to FIG. 4, shown is a
perspective view of a high strength, limited rotation gear 210 in
accordance with the present invention. Gear 210 includes a first
substantially planar surface 212 and a second substantially planar surface
214 (not shown) opposite surface 212 and essentially parallel thereto. An
aperture 216 is formed through gear 210, perpendicular to opposing
surfaces 212 and 214. As is implied by the drawing of FIG. 4, surface 212
and surface 214 are substantially identical to one another. A single gear
tooth 218 is integrally formed with gear 210 and includes a single contact
surface 220, tooth 218 being asymmetrically disposed with respect to
aperture 216.
The asymmetrical nature of tooth 218 is illustrated in FIG. 5 wherein a
comparison between the gear profile of the present invention and a
traditional gear profile is drawn. A traditional gear border profile 222
(shown in broken line) and traditional gear tooth profile 224 (also shown
in broken line) have been included in the FIG. 5 to facilitate this
comparison. As shown, the traditional gear is substantially similar to the
present gear 210 except for the respective configurations of the gear
teeth. The traditional gear tooth profile 224 is radially symmetrically
disposed with respect to aperture 216, each side of the tooth being
equidistant from a central rotational axis 226. That is, the traditional
gear tooth profile 224 includes two oppositely facing contact surfaces 220
and 224, each of which lies approximately the same distance from axis 226.
In normal operation, each surface 220 and 224 of the traditional gear
tooth contacts a separate tooth of another enmeshed gear and transmits or
receives a given amount of torque. This torque may be bidirectionally
applied to the tooth at a moment measured from central axis 226 to
approximately the center of the contact surface 220 or 224. Further, the
bidirectional torque applies stress to the gear at its weakest point,
namely where the tooth meets the main body of the gear, and where the
least amount of material is available to provide structural support. By
comparison, tooth 218 formed in accordance with the present invention
provides added structural support by limiting application of torque to a
single rotational direction, and by providing additional material to
withstand the resultant stress in that direction.
Referring now to FIG. 6, applied torque is shown to be efficiently
transmitted in a single rotational direction using a high strength gear in
accordance with the present invention. Additionally, it is readily
apparent how the stress created by this torque is better distributed along
the present gear profile than that of the prior art gear tooth. In FIG. 6,
two separate but substantially identical gears 210' and 210" are shown,
including teeth 218' and 218", and planar surfaces 212' and 212",
respectively. As is shown, a contact surface 220' (of gear 210') makes
substantial contact with contact surface 220" (of gear 210") as gear 210'
is rotated in a clockwise direction (indicated by arrow 228') about axis
226', forcing gear 210" to rotate in a counter-clockwise direction
(indicated by arrow 228"). As is also indicated by the arrows, torque
created when rotating gear 210' is distributed along the circumferential
length of tooth 218' and 218", thus allowing the additional material
forming teeth 218' and 218" to absorb the stress created by the torque.
This preserves the structural integrity of gear 210' and 210", increasing
the strength and reliability of the gear dramatically. Of course, it can
also be readily seen that rotating gear 210" in a clockwise direction
about axis 226' would force gear 210' to rotate about axis 226' in a
counter-clockwise direction. The same force distribution as described
above would apply equally in this situation. It is also important to note
the unidirectional nature of this gear configuration, wherein rotation of
gear 210' about axis 226' in a counter-clockwise direction would cause
surfaces 220' and 220" to disengage and no torque would be transmitted to
gear 210". Likewise, if gear 210" were rotated about axis 226" in a
counter-clockwise direction, surfaces 220" and 220' would disengage and no
torque would be transmitted to gear 210'.
To provide a gear with the capability of transmitting torque
bidirectionally, a gear profile such as depicted in FIG. 7 is used. As can
be seen, the design principle described above in connection with FIGS. 4-6
has been used in constructing a bidirectional gear 230 of FIG. 7, with two
substantial differences. First, gear 230 comprises substantially two
separate gear profiles similar to those of gear 210, wherein gear 230 has
been rendered bidirectional by reversing and stacking the separate gear
profiles. Second, each of the separate gear profiles comprising gear 230
include two teeth, as opposed to the single tooth of gear 210. Gear 230
substantially comprises a first gear profile 232 and a second gear profile
244. First gear profile 232 includes a first tooth 234 and a second tooth
236, spaced apart relative to one another and radially disposed from a
central aperture 238. First tooth 234 includes a first contact surface
240, and second tooth 236 includes a second contact surface 242, both
contact surfaces 240 and 236 transmitting torque to a complimentary gear
tooth when rotated thereagainst (as described in further detail below).
Second gear profile 244 includes a third tooth 246 and a fourth tooth 248
(not shown) spaced apart relative to one another and radially disposed
from central aperture 238 which extends through both gear profiles, 232
and 244. Similarly, third tooth 246 includes a third contact surface 250
(not shown) and fourth tooth 248 includes a fourth contact surface 252
(not shown), both contact surfaces being used to apply torque to a
complimentary gear tooth when rotated thereagainst.
Note that teeth 234 and 236 of profile 232 are disposed to provide torque
in an opposite direction in comparison to teeth 246 and 248 of gear
profile 244. That is, contact surfaces 240 and 242 of teeth 234 and 236,
respectively, are positioned to provide torque against complimentary teeth
in contact therewith when gear 230 is rotated in a clockwise direction
about an axis 254 through the center of aperture 238. In contrast, contact
surfaces 250 and 252 are positioned to provide torque against
complimentary teeth in contact therewith when gear 230 is rotated in a
counterclockwise direction about axis 254. Thus, gear profile 232 will
provide no torque when rotated in a counter-clockwise direction, and gear
profile 244 will provide no torque when rotated in a clockwise direction.
Referring now to FIGS. 8a and 8b, application of the high strength limited
rotation gear 230 (FIG. 7) to the synchronous operation of gearing
mechanism 24 (FIG. 3) is presented in accordance with the present
invention. As just described, a novel feature of mechanism 24 is that it
comprises two substantially identical bidirectional gears of the type
depicted in FIG. 7. That is, only a single gear design is necessary to
construct the bidirectional gearing mechanism 24 of FIG. 3 and FIGS. 8a
and 8b, thus greatly simplifying its manufacture and decreasing its
overall production cost. Synchronous gearing mechanism 24 generally
comprises first bidirectional gear 62 and second bidirectional gear 64,
with a portion of their respective teeth meshed together. In FIG. 8a, it
can be seen that gear 64 has simply been rotated about its central axis 65
relative to gear 62. Gear 62 includes a first gear profile 66 and a second
gear profile 68 which lies beneath profile 66 in the orientation of
mechanism 60. Gear 64 includes a third gear profile 70, identical to
profile 66, and a fourth gear profile 72, identical to profile 68, which
lies beneath profile 70 in the orientation of mechanism 60. Profile 66
includes a first tooth 74 and a second tooth 76; profile 68 includes a
third tooth 78 and a fourth tooth 79 (not shown); profile 70 includes a
fifth tooth 80 and a sixth tooth 82; and, profile 72 includes a seventh
tooth 84 and an eighth tooth 86 (shown in phantom). FIG. 8b illustrates
the relative orientations of the various features of gears 62 and 64 as
they appear from the reverse view from that shown in FIG. 8a. FIG. 8b also
illustrates the substantial similarities of gear profiles 72 and 68, as
described above.
Referring again to FIG. 8a, the operation of mechanism 24 will be described
in detail. Although either bidirectional gear 62 or 64 could be used to
drive the other respective gear, let us assume for purposes of
illustration that gear 64 is used to drive gear 62, as may be accomplished
by inserting pin 8 or 9 (FIG. 3) or similar means into gear 64 through
aperture 67. If gear 64 is rotated in a counter-clockwise direction about
axis 65, the contact surface of tooth 82 will make substantial contact
with the contact surface of tooth 76 of gear 62. It is, of course, assumed
that gear 62 is rotatably secured about a central axis 63 such that no
translational movement is possible. As tooth 82 is rotated into tooth 76,
a torque is transmitted from tooth 82 to gear 62 causing it to rotate in a
clockwise direction about axis 63. As can be seen by reference to the
figure, this torque can only be transmitted between the gears in a limited
range of motion. That is, tooth 82 and tooth 76 will make substantial
contact for only a limited angular range of motion. In one embodiment of
the present invention, the range of motion is approximately 20 degrees.
Note that as gear 64 is rotated counter-clockwise, tooth 86 does not
transmit torque to tooth 78a. If gear 64 is rotated in a clockwise
direction about axis 65, the contact surface of tooth 86 will make
substantial contact with the contact surface of tooth 78a. As tooth 86 is
rotated into tooth 78, a torque is transmitted from tooth 86 to gear 62
causing it to rotate in a counter-clockwise direction about axis 63. Note
also that when gear 64 is rotated in a clockwise direction, tooth 82 does
not transmit torque to tooth 76.
One of the important advantages to the design of bidirectional mechanism 24
is that each of the component gears 62 and 64 are identical and thus
easier to manufacture and are interchangeable. Another important feature
is that mechanism 60 essentially comprises a synchronous gearing
mechanism. That is, for a limited range of motion, rotating either gear
causes the other gear to rotate a substantially identical amount. This
feature can best be seen by reference to FIG. 6.
Shown in FIG. 9 is an enlarged view of synchronous gearing mechanism 24
used within keyboard 10 of the present invention. As shown, bidirectional
gear 62 has an additional moment element 90 attached thereto or integrally
formed therewith. Likewise, bidirectional gear 64 has an additional moment
element 92 attached thereto or integrally formed therewith. Moment element
90 includes a first aperture 94 and a second aperture 96 for connecting
additional elements to gear 62 of gearing mechanism 60. Likewise, moment
element 92 includes a third aperture 98 and a fourth aperture 100 for
connecting additional elements to gear 64 of mechanism 60.
For purposes of illustration, we will assume that each gear 62 and 64 is
rotatably secured about its respective central axis. In a normal
operational configuration, the teeth of the bidirectional gears are meshed
as shown in the FIG. 9, and as described in relation to FIG. 8a. Thus,
tooth 82 makes contact with tooth 76, and tooth 78 makes contact with
tooth 86. If a force is applied to element 92 in the direction of arrow
102, gear 64 will rotate in a counter-clockwise direction about axis 65.
This rotation will cause tooth 86 to transmit a torque to gear 62 via
tooth 76, and cause gear 62 to rotate in a clockwise direction about axis
63. This rotation will cause member 90 to move in the direction indicated
by arrow 104. Likewise, if a force is applied to moment element 90 in the
direction indicated by arrow 104, gear 62 will rotate in a clockwise
direction about axis 63, thereby causing tooth 78 to transmit a torque to
gear 65 via tooth 86. Gear 64 will rotate in a counter-clockwise direction
about axis 65, causing moment element 92 to rotate in the direction
indicated by arrow 102. The mechanism will, of course maintain synchronous
motion if a force is applied to either of the moment elements 90 or 92 in
a direction opposite to that indicated by the arrows.
In practicing the present invention, it may be advantageous to quantize the
angles of rotation available to the separate halves 12 and 16 of keyboard
10. This can be achieved by including detents (not shown), formed in a
known manner and located at the distal ends of each of the moment elements
90 and 92 facing base 20 (FIG. 3). The detents can be configured to allow
only specific ranges of quantized movement, such as, for example, 3
degrees per detent. Additionally, the detents can be used to ensure that a
minimum amount of force per side must be applied to the front corners of
the keyboard before the separate halves will rotate. The detents can
prevent inadvertent rotation of the key fields during keyboard use, and
also provide a tactile feel to the user during the adjustment process.
It is important to note that, although the present invention has been
described in conjunction with a specific synchronous coupling means, it is
contemplated that alternative synchronizing means could be used to attain
the desired synchronous complementary motion of the separate halves 12 and
14. Other viable designs could include the use of linkages, belts,
pressure wheels, etc. For example, and with brief reference to FIG. 4, an
alternative embodiment of the present invention comprising synchronizing
means employing a linkage mechanism is shown. In FIG. 10, left key field
104 and right key field 103 are pivotably mounted by pivot pins 101 and
102 to base 113. A space bar 110 is centrally mounted to base 113 and
disposed between the central lower edges of key fields 104 and 103. A left
link 107 is pivotably mounted to the underside of left key field 104 and
extends downward to a linkage pin 114 slideably disposed within a guide
slot 109 formed within base 113. Similarly, a right link 108 is pivotably
mounted to the underside of right key field 103 and extends downward to
linkage pin 114 disposed within guide slot 109. When a user grasps and
moves either left key field 104 or right key field 103 from its first,
closed position, linkage bars 107 and 108 cooperatively cause left and
right key fields 103 and 104 to move to the second, open positions 104'
and 103'. The subtended angle between left and right key fields 103' and
104' remains symmetrically distributed about space bar 110 by virtue of
linkage pin 114 moving to its second position 114' within slot 109.
Reference is now made to FIGS. 11A and 11B, wherein an alternative
embodiment of the integrated adjustable keyboard of the present invention
incorporating supports for the user's hands is shown. In Figs. 11A and
11B, a pair of compliantly coupled detachable palm rests 2 and 6 is shown,
one palm rest being attached to each key half 12 and 16. As shown in FIGS.
11A and 11B, palm rests 2 and 6 enable a user to gain and maintain a
comfortable posture throughout the range of motion provided by movable key
halves 12 and 16. The attachment means used t | | |
