Supports – Brackets – Adjustable
Reexamination Certificate
1999-02-12
2001-05-08
Braun, Leslie A. (Department: 3632)
Supports
Brackets
Adjustable
C248S118300, C248S918000
Reexamination Certificate
active
06227508
ABSTRACT:
FIELD OF THE INVENTION
The current invention is directed to an apparatus for providing an adjustable support surface, such as that used to support visual monitors or computer keyboards. More specifically, the current invention is directed to an adjustable support apparatus that is capable of assuming varying heights and inclinations.
BACKGROUND OF THE INVENTION
Certain objects, such as data entry keyboards for use in connection with a computer and visual monitors, have been mounted on a support surface formed on an adjustable support apparatus that permits varying the height, as well as the inclination, of the support surface. Varying the height and inclination of the object reduces strain on the user. For example, varying the height and inclination of a keyboard permits its positioning to be adapted to the characteristics and preferences of the user and can prevent carpel tunnel syndrome.
In the past, apparatus for supporting keyboards have included an arm, the proximal end of which is rotatably mounted on a base that can be affixed to the underside of a desk. A support plate, on which the keyboard is mounted, is rotatably mounted on the distal end of the arm. Rotating the arm up or down at the base allows the height of the keyboard to be adjusted, while rotation of the support plate on the arm allows the inclination of the keyboard to be adjusted. Unfortunately, such apparatus suffer from several important drawbacks.
The first drawback concerns the locking of the orientation set by the apparatus. Various locking mechanisms have been used to lock the support arm and support plate in the desired orientation. Unfortunately, these mechanisms typically require operation of two or more knobs or levers to effect complete locking or unlocking—for example, one knob to lock/unlock the arm and another to lock/unlock the support plate. This makes adjustment of the apparatus more cumbersome.
The second drawback arises because traditional methods for mounting the support plate to the support arm cause the inclination of the support plate to vary as the arm is rotated up and down. Thus, although the user will often desire to maintain a constant, horizontal inclination for the keyboard, the resetting of the height of the keyboard will necessitate resetting the inclination to maintain the keyboard horizontal.
The third drawback concerns restraining the downward motion of the support arm. If unrestrained, the weight load resulting from the combined weight of the support arm, support plate and keyboard creates a downward wight moment that can cause the support plate to drop very rapidly when the arm locking mechanism is disengaged. This could result in the keyboard striking the user or otherwise cause injury to the user or damage to the equipment. Consequently, various mechanisms have been used to restrain the downward motion of the arm.
One approach involves the use of a torsion spring that applies a moment that opposes the weight moment by tending to rotate the support arm upward. Unfortunately, the moment applied by a torsion spring is more or less linearly proportional to the angular orientation of the support arm. This is in contrast to the moment applied by the supported weight, which initially increases as the arm is rotated upward from its minimum height position, reaching a maximum when the arm is extended horizontally, and then decreases as the arm is further rotated to its maximum height. Thus, if a torsion spring is arranged to provide adequate force to offset the maximum weight moment when the arm is horizontal, as well as to provide at least some force when the arm is near its raised position, the upward force it will apply when the arm is in the lowered position can become excessive.
Another approach involves the use of a gas filled cylinder, similar to those used to restrain downward motion of the tailgate or hatch back in an automobile, which produces a substantially constant force. However, as heretofore used, the opposing moment resulting from gas filled cylinders did not match that of the weight moment as the arm rotated over its range of orientations so as to be a maximum value when the arm was horizontal, and weight moment a maximum, and a minimum value when the arm was rotated into its maximum or minimum height orientations, when the weight moment was at a minimum value.
Recently, it has been proposed that support apparatus for use in conjunction with data entry keyboards be capable of supporting the keyboard in positions that allow it to be used both when the user is seated and when standing. It is thought that affording brief opportunities for standing provide a respite that will enhance the productivity of data entry personnel. Achieving this objective will require a larger range of support plate heights, as compared to apparatus used only in the seated position. This, in turn, will require a longer support arm, which will result in a larger maximum moment as a result of the weight load, as well as a much larger difference between the maximum and minimum moments. In such applications, the failure of conventional approaches to more closely match the opposing moment to the weight moment is especially undesirable.
Consequently, it would be desirable to provide an adjustable support apparatus for an object, such as a keyboard or a visual monitor, that allowed both the height and inclination locking mechanisms to be engaged and disengaged by a single operation of the user's hand, that allowed the inclination of the support to be maintained constant throughout the range of vertical motion, and that provided for smoother and safer operation by creating an opposing moment that more closely matched the moment resulting from the supported weight.
SUMMARY OF THE INVENTION
It is an object of the current invention to provide an adjustable support apparatus for an object, such as a keyboard or a visual monitor, that allowed both the height and inclination locking mechanisms to be engaged and disengaged by a single operation of the user's hand, that allowed the inclination of the support to be maintained constant throughout the range of vertical motion, and that provided for smoother and safer operation by creating an opposing moment that more closely matched the moment resulting from the supported weight.
These and other objects are accomplished in an adjustable support apparatus for supporting an object thereon comprising (i) a base, (ii) a rotatable support arm coupled to the base, the support arm capable of being rotated over a range of angular orientations within a vertical plane, (iii) a support member coupled to the support arm, the support member forming a support surface for supporting the object thereon, whereby the support member transmits a load onto the support arm that creates a first varying moment tending to rotate the support arm downward within the vertical plane, the magnitude of the first moment varying depending on the angular orientation into which the support arm is rotated, (iv) means for generating a substantially constant force, and (v) means for transmitting the substantially constant force to the arm so as to create a second varying moment tending to rotate the support arm upward, the magnitude of the second moment varying depending on the angular orientation to which the support arm is rotated, whereby the downward rotation of the support arm is at least partially resisted, and upward rotation of the support arm is more easily effected by the user.
Preferably, the means for generating a constant force comprises an elongate spring member pre-stressed so as to form a winding that can be mounted on a rotatable core and having a first end, whereby extending the first end so as to unwind the spring member from the core generates a force tending to retract the first end of the spring member, the retraction force being substantially constant regardless of the amount by which the first end is extended within a predetermined range of extensions.
The invention also encompasses an adjustable support apparatus having (i) first locking means for locking th
McClanahan David D.
Panzarella Thomas A.
Braun Leslie A.
Cook Specialty Company
Landry Walter
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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