Hand, wrist and/or lower arm support pad and assemblies

A hand, wrist and/or lower arm support pad and related assemblies are disclosed for use by operators of typewriter or computer keyboards, ten key pads and/or various computer peripherals such as a trackball or computer mouse. The support pad includes an enclosure defining a containment area having a flowable material therein and structure to assure retention of the enclosure at a selected location. The retention structure may be integral to the enclosure and/or may be associated with related assemblies. The flowable material preferably exhibits fluid-like characteristics, and, more preferably, is characterized by a non-constant shear rate to shear stress ratio. In some embodiments, it is preferred that the material will not flow under its own weight (i.e., no, or substantially reduced, cold flow characteristics).

FIELD OF THE INVENTION 
This invention relates to pads and rests, and, more particularly, relates 
to support pads for hands, wrists, and/or lower arms used by an operator 
of a keyboard, ten key pad, computer mouse, trackball or the like. 
BACKGROUND OF THE INVENTION 
Operators of various keyboard and/or computer peripheral devices are known 
to experience discomfort and fatigue of the fingers, wrist and/or lower 
arm after extended periods of use of such devices. At the extreme, 
conditions such as various carpal tunnel irritations and repetitive motion 
disorders have been reported. 
A variety of rests and pads have been devised in response to these 
occurrences. The most typical examples of such pads and rests are fabric 
covered foam articles. Such foam rests, however, have not proven 
altogether successful, since the foam typically exhibits only limited 
ability to conform to pressures exerted by the user on the pad. These 
articles thus may actually apply pressure to locations on the hand, wrist 
and/or lower arm during use, or induce unnatural or uncomfortable hand to 
forearm alignment. 
Other examples of devices to alleviate the above-described conditions are 
known which include cradles movable on rollers or the like. These devices, 
however, are unduly complex, may be expensive to produce, and, in some 
cases, may limit the range of motion desired by the operator of a device 
such as a computer mouse. Further improvements to support pads of these 
types could thus still be utilized. 
SUMMARY OF THE INVENTION 
This invention provides an improved hand, wrist and/or lower arm support 
pad and related assemblies for use by operators of devices such as 
keyboards of various types and/or autolocating mechanisms employed in 
computer processing (for example, a trackball or a computer mouse). The 
pad not only provides greater comfort and improved, more neutral, 
positioning of the user's hands and wrists, but also provides conformable 
wrist, hand and/or lower arm location substantially without pressure 
points which may be felt by the user (thus providing a reduction of wrist, 
finger and/or forearm fatigue and soreness), as well as a tactile cue for 
proper hand location relative to the device. 
The support pad includes an enclosure defining a containment area, the 
containment area having a flowable material therein. Position retention 
structure is associated with the enclosure to enable retention of the 
enclosure at a selected location relative to either the operator or the 
device. 
Position retention structure could take a variety of forms, including an 
edge portion configured to nestle against a side of the device, a friction 
material such as hook and loop or non-slip plastic or rubber material, 
and/or retention trays or pad bases. 
The enclosure preferably is configured with at least a first arcuate edge 
portion. In its embodiment for use with a computer mouse, the outer edge 
of the enclosure may be substantially circular. 
The flowable material held in the containment area of the enclosure is 
preferably a pressure compensating material having fluid-like 
characteristics. More particularly, the material is preferably 
characterized by a non-constant shear rate to shear stress ratio, flowing 
more readily when higher shear stress is applied than when lower shear 
stress is applied. For some embodiments of the invention, the material has 
a viscosity selected to avoid cold flow of the material so that the 
material will not flow to its own weight. 
The improved support pad of this invention for use by operators of a 
computer mouse provides more precise hand movement for finer mouse 
manipulations due to greatly reduced friction and the fluidic movement of 
the support pad. 
It is therefore an object of this invention to provide an improved hand, 
wrist and/or lower arm support pad and assemblies for use by operators of 
manually manipulable devices maintained at a utilization area. 
It is another object of this invention to provide an improved support pad 
for use by an operator of a keyboard, trackball, computer mouse or the 
like which secures greater comfort, better positioning, freer movement, 
and less fatigue of the hand, wrist and/or lower arm of the operator. 
It is still another object of this invention to provide a hand, wrist or 
lower arm support pad for use by an operator of a manually manipulable 
device maintained at a utilization surface, the support pad including an 
enclosure defining a containment area, position retention structure 
associated with the enclosure to enable retention of the enclosure at a 
selected location relative to one of the operator and the device, and a 
flowable material in the containment area of the enclosure. 
It is yet another object of this invention to provide a hand, wrist or 
lower arm support pad for use by an operator of a manually manipulable 
device maintained at a utilization surface, the support pad including an 
enclosure having upper and lower surface portions joined together at outer 
edges to define a containment area, the joined edges defining at least a 
first arcuate edge portion of the enclosure, and flowable pressure 
compensating material in the containment area of the enclosure, the 
material having fluid-like characteristics. 
It is still another object of this invention to provide a hand, wrist or 
lower arm support pad for use by an operator of a computer mouse, the 
support pad including an enclosure defining a containment area and having 
an overall arcuate outer edge defining an interface between upper and 
lower surfaces of the enclosure, position retention structure associated 
with the enclosure to enable retention of the enclosure at a selected 
position relative to one of the operator and the computer mouse, and 
flowable material in the containment area of the enclosure. 
It is yet another object of this invention to provide a hand, wrist or 
lower arm support pad for use by an operator of a manually manipulable 
device maintained at a utilization surface, the support pad including an 
enclosure defining a containment area with a flowable material therein, 
the flowable material being characterized by a non-constant shear rate to 
shear stress ratio. 
It is yet another object of this invention to provide a hand, wrist or 
lower arm support pad for use by an operator of a manually manipulable 
device maintained at a utilization surface, the support pad including an 
enclosure defining a containment area with a flowable material therein, 
the flowable material being characterized by being resistant to cold flow. 
With these and other objects in view, which will become apparent to one 
skilled in the art as the description proceeds, this invention resides in 
the novel construction, combination, and arrangement of parts 
substantially as hereinafter described, and more particularly defined by 
the appended claims, it being understood that changes in the precise 
embodiment of the herein disclosed invention are meant to be included as 
come within the scope of the claims.

DESCRIPTION OF THE INVENTION 
Various embodiments of the support pad and related assemblies of this 
invention are illustrated in the FIGURES. Illustrated in FIGS. 1 and 2 is 
a pad arrangement suitable for a full computer keyboard. In FIG. 3 another 
pad for computer and/or typewriter keyboards is shown. FIGS. 4 and 5 show 
a pad arrangement adapted for the alphanumeric portion of a computer 
keyboard or a typewriter, while in FIGS. 6 and 7 a pad arrangement adapted 
for ten key machines (or related keyboard section or a computer keyboard) 
or computer trackballs is illustrated. FIGS. 9 through 13 show a pad 
arrangement for a computer mouse (an autolocating peripheral used to 
locate a cursor on a computer monitor). 
Support pad 15 of FIGS. 1 and 2 includes enclosure 17 formed by upper and 
lower surface sheets 19 and 21 joined (by heat sealing or the like) at 
their outer edges 23 and 25 thus defining a containment area 27 (see FIG. 
8). Sheets 19 and 21, and thus enclosure 17, include a straight edge 
portion 29 and a plurality of arcuate edge portions 31, some of which, 
together with closed seams 32, define segments 33, 35, and 37 of enclosure 
17. Containment area 27 is filled with a conformable, pressure 
compensating flowable material (which will be discussed in greater detail 
hereinafter). Upper surface 19 may be covered by fabric 38 (for example 
stretch nylon Lycra or brushed nylon tricot) joined at outer edge 23 (by 
heat sealing or the like). 
Provision of straight edge portion 29 assures (even without further 
securement) a degree of position retention of pad 15 relative to keyboard 
39 when nestled against keyboard edge 41. The various arcuate corners 31 
provide better flow and pad movement characteristics responsive to user 
applied pressures. Improved position retention of the support pad may be 
accomplished utilizing friction material 43, which may be any of separate 
attached pads of low- or non-slip material such as neoprene rubber or the 
like, hook and loop) material, such as Velcro pads (thus requiring mating 
pad or pads 45 on the utilization surface or, as shown, on a separate 
assembly base 47), spray on material applied directly to lower enclosure 
surface sheet 21, or lower surface sheet 21 itself made of a low- or 
non-slip material. 
FIG. 3 illustrates a greatly simplified keyboard pad 49 without segments 
defined therein but otherwise of similar construction to that shown in 
FIG. 1. In such case, however, desired flow characteristics are provided 
in some cases by increasing the viscosity of flowable material held in the 
containment area of enclosure 51 of pad 49. Support pad 49 is primarily 
retained at a position adjacent to a keyboard by provision of straight 
edge 53 (for abutment against the keyboard), though any of the various 
other position retention techniques above-described could be utilized. 
Where desired, for example for use with a typewriter or where space or 
other considerations might require, support pad 55 shown in FIGS. 4 and 5 
can be utilized. Similar in construction to the pad shown in FIG. 1, 
support pad 55 includes only two segments 57 and 59 similar in size to or 
smaller than segments 33 and 35 of support pad 15. Multiple pads 55 may be 
used in combination to span an entire computer keyboard. Again the various 
position retention techniques heretofore set forth apply. 
Support pad 61 shown in FIGS. 6 and 7 is adapted for use with smaller 
keyboards (ten key machines, calculators or the like), keyboard segments 
(such as numeric key section 63 of computer keyboard 39), a trackball, or 
in side-by-side arrangement with other pads 61 to span any keyboard 
length, but is otherwise similar in construction and operation to the 
support pads of this invention previously described herein. However, 
support pad 61 is formed of a single enclosure segment 65 similar in size 
to or smaller than segment 37 of support pad 15. Support pad 61 in some 
cases may be used in combination with support pad 55 or with other ones of 
pad 61 (the arrangement of multiple pads 61 along a keyboard may in fact 
be the best mode yet devised for achieving the advantages of this 
invention as applied to computer or typewriter keyboards). 
FIG. 8 is a sectional illustration (taken from FIG. 5, it being understood 
that the illustration represents a section of any of the support pads 15, 
49, 55 or 61) showing containment of the flowable material within 
enclosure 17 of the support pads of this invention. As illustrated, sheets 
19 and 21 are joined to form an envelope of selected thickness, the amount 
and viscosity of flowable material, and volume, size and seam 32 placement 
and length (where present) of enclosure 17 being selected to provide 
desired flow characteristics, pad movement, pressure responsiveness and 
pad rebound (or, in the alternative, pad memory). 
FIGS. 9 through 14 illustrate an embodiment of the support pad and related 
assemblies of this invention for utilization by operators of a computer 
mouse. Support pad 67 is shown in FIGS. 9, 10 and 11 with differently 
configured bases 69, 71 and 73, respectively. Bases 69 and 71 include pad 
positioning area 75 and operating surface 77 for mouse manipulation 
thereat. Base 73 includes only positioning area 75, mouse manipulation 
occurring on any adjacent surface. 
Alternatively, position retention techniques requiring no related base or 
matable attachment, as heretofore discussed (i.e., integrated or separate 
low- or non-slip materials, spray on materials, and the like), could be 
utilized with mouse manipulation occurring on the adjacent surface. 
Moreover, support pad 67 could be applied directly to the wrist of a user 
(by straps, matable Velcro attachments at the pad and wrist, or the like), 
position retention relative to the utilization surface in such case being 
relatively less important. 
Support pad 67 includes enclosure 79 formed by substantially circular upper 
and lower surface sheets 81 and 83, respectively. Sheets 81 and 83 are 
joined (by heat sealing, for example) at outer edge 85 thus defining 
containment area 87 having a conformable, pressure compensating flowable 
material sealed therein. Fabric cover 88 over upper surface sheet 81 is 
joined at outer edge 85 as heretofore disclosed. 
As shown in FIG. 12, position retention may be secured by velcro pad 89 
centrally affixed (for example, by gluing or the like) to lower surface 
sheet 83 and matable with Velcro pad 91 at base 73. As shown in FIG. 13, 
for a free standing pad (i.e., one utilizing no separate base in a pad 
assembly), a neoprene rubber or other non-slip material 93 may be 
centrally affixed to sheet 83. 
By utilizing position retention materials only at the center of the lower 
sheet of the pad, preferably where the exposed lower sheet surface area 
not having retention materials applied thereat exceeds the surface area 
where retention materials are applied thereat, for example as shown in 
FIGS. 2, 5, 7, 8, 12, 13 and 14, a type of sliding parallelogram movement 
is achieved. That is to say, starting with the user's wrist centered at 
rest on, for example, support pad 67, the pad will accommodate movement of 
the wrist away from the original center with increasing resistance the 
further the movement of the wrist from the original center. Friction 
between the appendage being supported and the top surface of the support 
pad allows lateral movement to cause the upper surface sheet of the pad to 
move, thereby deforming the leading edge of the pad (in the lateral 
direction of the force) and pulling the trailing edge of the pad up. When 
lateral forces applied by the user are relaxed, the weight of the wrist 
(i.e., downward force) causes the pad to return to its original position 
and shape with the wrist centered on the pad. 
Thus, pad 67 tends to behave as a self centering support, movement of the 
entire arm or forearm being used to manipulate the mouse instead of 
articulation of the wrist in a horizontal plane. Pad 67, utilizing the 
conformable, flowable material therein, allows the user's wrist to be 
supported in a neutral, natural position without regard to the position of 
the user's arm relative to the utilization surface over which the mouse is 
manipulated. 
Upper and lower surface sheets of the various embodiments of the invention 
herein set forth may be made of various materials including any flexible 
light weight, preferably pliable material having a certain degree of 
elasticity and resistance to puncturing. Materials having a thickness of 
between about 0.1 and 0.8 millimeters, depending on the material are 
typical. Polyurethane, polyvinyl, acetal, acrylic, cellulosic, chlorinated 
polyether, flourocarbon (TFE, CTEE, or FEP), nylon (polyamide), 
polycarbonate, polyetheylene, polystyrene, polyester, and polysulfone 
materials could all be utilized (preferably 0.2 millimeter polyurethane). 
If desired, convexivity may be introduced into the upper and lower surface 
sheets, for example by vacuum forming (see U.S. Pat. No. 5,159,717, the 
contents of which are incorporated hereinto by this reference). 
Bases 47, 69, 71 and 73 may be made of any desired material, including 
rigid plastics materials (particularly useful for known bases of the type 
used under keyboards such as base 47) or more cushioned bases made of 
foamed plastic or rubber material such as polyethylene, ethafoam, EVA or 
neoprene foam rubber (particularly useful as bases 69, 71 or 73). 
Regarding the method of constructing the various embodiments of the present 
invention, after cutting into the desired shape, upper and lower surface 
sheets are affixed to each other at their outer edges, for example by heat 
sealing or other methods known to those skilled in the art. The seal 
between the sheets is a substantially flat surface. A small opening is 
left in the enclosure seal for insertion of a filling apparatus into the 
thus formed enclosure. The filling apparatus is inserted into the opening 
and a predetermined volume of the flowable material is placed into the 
enclosure of the support pad. The filling apparatus is then removed and 
the opening in the enclosure is sealed. Cover fabrics are then cut and 
secured as heretofore discussed (alternatively, they may be applied in a 
single heat sealing step when the upper and lower sheets are affixed and 
the opening sealed). It is to be realized, that the cutting of the 
material into the final shape of the pads may occur at any time during the 
process. 
While it is typically unnecessary to remove air from the enclosure prior to 
sealing (because air will also act as a shock absorbing medium, and, in 
fact, could be utilized as the sole flowable material in the enclosure), 
air removal can be performed if desired (i.e., where a pad having no 
"bounce" is required) prior to sealing of the opening so that only 
flowable material will occupy the containment area of the enclosure. 
Shape and size of the enclosure are application specific. The size of the 
enclosure, or enclosure segment, is typically slightly larger 
(approximately 10%) than the surface area of the portion of the appendage 
being supported. The shape of the upper and lower surface sheets (and thus 
the enclosure) determines the range of lateral movement of the pad which 
occurs pursuant to user applied forces. A circular enclosure allows equal 
range of movement in all lateral directions. An oval shaped enclosure 
would allow the range of motion to be modified so there is less range of 
motion in the direction of the longer axis of the oval (primarily due to 
greater required deformation of the longer edges of the enclosure). A 
square shaped enclosure would allow a greater range of motion in 
directions perpendicular to the sides (though non-simultaneously). A 
rectangularly shaped enclosure would allow a greater range of motion in 
the shorter axis than in the longer axis. 
The volume of fluid contained in the enclosure of the support pads of this 
invention would typically be about 25% to 75% of the maximum volume 
capacity of the enclosure (achievable without significant deformation of 
the enclosure material). As the fill volume approaches the upper part of 
this range, stability of the pad decreases. In other words, the force 
required to laterally move the pad decreases. However, increased viscosity 
of the material tends to increase stability of the pad because of the 
greater applied forces required to cause pad movement. The variation of 
fill volume to fill material viscosity is thus utilizable to achieve a 
variety of pad characteristics. Other variables utilized to vary pad 
characteristics include higher durometer and thicker upper and lower 
surface sheet materials, and size and type of position retention material 
utilized. 
Pad 15 preferably measures about 4.25 inches by 19.375 inches, with a 
thickness of about 0.812 inches when filled. The various segments 33, 35 
and 37 are each of about equal size. Seams 32 extend into the pad about 
2.75 inches (leaving an unobstructed passage between the end of the seams 
and straight edge 29 of about 1.5 inches). 
Pad 49 preferably measures about 3 inches by 19.375 inches, with a 
thickness of about 0.625 inches when filled. Support pad 55 preferably has 
a length of about 12.625 inches (other measurements being about the same 
as set forth above for pad 15), with segments 57 and 59 being of about 
equal size. Pad 61 preferably measures about 4.75 inches square with two 
adjacent corners having about a 0.5 inch radius and the opposite two 
adjacent corners having about a 2 inch radius. Pad 61 has a thickness of 
about 0.7 inches (preferably about 0.72 inches) when filled. Pad 67 
preferably has a diameter of about 4.5 inches and a thickness of about 
0.625 inches when filled. 
Where a non-slip retention pad (for example of neoprene rubber) such as pad 
93 in FIG. 13 is to be utilized for position retention of support pads 61 
or 67, the material is preferably about 3 inches in diameter and about 
one-eighth to one-sixteenth of an inch thick. The retention pad is 
attached substantially at the center of the lower surface sheet of the 
support pad (by gluing or the like). Where hook and loop material is to be 
utilized, three-quarter inch to 3 inch hook and loop material pads may be 
utilized. 
The flowable material utilized to occupy the containment area of the 
enclosures of the various embodiments of the invention herein disclosed 
may be any flowable material which reacts to an applied force by migrating 
to other regions of the support pad to more effectively distribute forces 
over a larger area of the pad. Thus the material must exhibit fluid-like 
characteristics. Materials such as wax, glycerin, water, salt water, 
grease, fats, oils, propylene glycol, syrup and even air or some particle 
materials either alone or in mixture with a fluid material may thus be 
used. Other appropriate flowable materials are HB Fuller 1454 Hot Melt (a 
flowable microcrystalline wax) and glycerine and the various materials 
produced by Alden Laboratories, Inc. under the trademark (either of which 
are preferred for their nontoxicity). The preferred materials are 
compositions including wax, oil and glass micro-spheres. For more detailed 
disclosure of some such materials that may be appropriate for use with 
this invention see U.S. Pat. Nos. 5,204,154, 5,100,712, 5,093,138, 
4,255,202 and 3,635,849, the contents of which are incorporated hereinto 
by this reference. 
The preferred materials for use with this invention, such as the 
above-mentioned materials, are flowable while not having total memory. In 
other words once deformed, the material will not always return to its 
original shape (thus providing a tactile cue for the user when returning 
to use of a keyboard having such a support pad adjacent thereto). However, 
some materials appropriate for use in this invention do exhibit a degree 
of gel strength, the gel structure being broken merely by applying a small 
but sufficient force to the pad, and these materials are preferred for 
support pads of this invention in many keyboard application. 
Many of the above mentioned materials, and the flowable material preferably 
utilized in this invention, behave in an non-Newtonian manner, because 
their viscosities change when the shear rate changes. In other words, the 
ratio of shear rate (flow) to shear stress (force) is not constant. These 
materials are typically either pseudoplastic or thixotropic. A 
pseudoplastic material is one which appears to have a yield stress beyond 
which flow commences and increases sharply with an increase in stress. In 
practice, the materials exhibit flow at all shear stresses although the 
ratio of flow to force increases negligibly until the force exceeds the 
apparent yield stress. The flow rate of a thixotropic material increases 
with increasing duration of agitation as well as with increased shear 
stress. In other words, the flow rate is time dependent. When agitation is 
stopped, internal shear stress can exhibit hysteresis. Upon re-agitation, 
less force is generally required to create a given flow than is required 
for the first agitation. The fact that the materials preferably used in 
this invention flow more readily when higher shear stress is applied is 
advantageous. 
The flowable materials used in the present invention have a viscosity in a 
range of between about 50 and 250,000 centipoise, and are selected to 
provide good pressure distribution throughout the entire area of the hand, 
wrist and/or lower arm in contact with the pad. For example, the preferred 
viscosity of the flowable material used in support pads 15, 49, 55 and 61 
is between about 10,000 and 250,000 centipoise. For applications where no 
or reduced cold flow (i.e. the tendency to flow to its own weight) is 
desired, for example to achieve a pad having memory, and thus providing a 
tactile cue, of hand, wrist or lower arm placement, the viscosity of the 
material should be in the 150,000 to 250,000 centipoise range (for example 
Alden Laboratories Inc. formula no. 2005). 
Mouse support pad 67, preferably allowing a greater degree of pad movement 
and responsiveness to user arm movement, would require a less viscous 
material (between about 50 and 100,000 centipoise, and preferably between 
about 5,000 and 10,000 centipoise). Alden Laboratories Inc. formula no. 
3020 has been found to be a material having a viscosity achieving the 
desired characteristics. 
As discussed hereinabove, the amount of fill and the volume of the pad also 
affect the range of parallelogram type pad motion achieved. For a round 
pad 67, 25% to 75% of the volume of the enclosure could be filled for 
useful embodiments of this invention. For example, a pad 67 having a 
diameter of about 4.5 inches and a volume of about 12 cubic inches, about 
6.8 cubic inches of material is preferably placed into the containment 
area of enclosure 79. 
As may be appreciated, this invention provides an improved hand, wrist 
and/or lower arm support pad and related assemblies for use by an operator 
of a device such as a keyboard, trackball or computer mouse, the pad 
providing for greater comfort, improved positioning of the user's hands 
and wrists, conformable wrist, hand and/or lower arm location 
substantially without pressure points, and a tactile cue for proper hand 
relocation relative to the device. The improved support pad of this 
invention for use by operators of a computer mouse provides more precise 
hand movement for finer mouse manipulations due to greatly reduced 
friction and the fluidic movement and resistance of the support pad.