Patent Abstract:
The present invention concerns a mechanism for adjusting the angle of an auxiliary support mounted on an auxiliary support mechanism. The mechanism may have a first member having a plurality of surfaces mounted on the end of an auxiliary support mechanism. The mechanism may also have a second member having a plurality of surfaces slideably enveloping said first member. The mechanism may still further have a third member movably connected to the auxiliary support mechanism as well as a spring member.

Full Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an auxiliary support mechanisms, such as those used to support the keyboard of a personal computer. The present invention permits the angle of the auxiliary work surface to be adjusted to improve the ergonomics of the work surface. 
     FIELD OF THE INVENTION 
     Personal Computers (PCs) have become ubiquitous in many industry and office environments. The input means most commonly used appears to be the keyboard. However, it is generally thought that use of a keyboard that is not positioned properly can lead to repetitive motion injury such as carpal tunnel syndrome. Thus, it is important to be able to properly position the keyboard. 
     One line of advances was the development of the auxiliary support mechanisms to position, for instance, a keyboard where a PC user would find it convenient. The earliest of these was developed by Hannah et al. (U.S. Pat. No. 4,826,123) and used a four-bar parallelogram linkage. Another approach was that of McConnell (U.S. Pat. No. 5,257,767) which used a four-bar non-parallelogram trapezoidal linkages. Yet another distinctly different approach to positioning, for instance, a keyboard, was my own development (U.S. Pat. No. 5,924,664) which used a five-bar mechanism including a slider joint. 
     Some keyboard support surfaces heretofore available have incorporated a tilt adjustment device allowing the keyboard support surface to be adjusted over a range of tilt angles. For instance, U.S. Pat. No. 6,148,739 to Martin, U.S. Pat. No. 6,135,405 to Jones et al., U.S. Pat. No. 5,961,231 to Ambrose, U.S. Pat. No. 5,775,657 to Hung, U.S. Pat. No. 5,704,299 to Corpuz, Jr., et al., and U.S. Pat. No. 5,692,712 to Weinschenk, Jr., et al. Nonetheless, the range of available tilt angles available has been limited. 
     Ergonomists advise us that the lowest risk of repetitive motion injury occurs when the keyboard angle is slightly negative so that the bottom of the front edge (i.e, the edge of the keyboard closest to the user) of the keyboard is higher than the bottom of the rear edge (i.e, the edge of the keyboard furthest from the user) of the keyboard. Accordingly, there was a need for a shelf adjustment mechanism that provides an improved means of achieving the ergonomically desired negative tilt. 
     BRIEF SUMMARY OF THE INVENTION 
     One aspect of the present invention is to provide an adjustable support for computer keyboards and the like. In such an embodiment, the adjustable support may include a support member shaped to retain an associated keyboard thereon. The support member may be pivotally mounted to shift about a generally horizontal pivot axis to define a tilt angle for the support member and the keyboard with respect to a user, wherein the tilt angle is adjustable within a predetermined tilt range. Desirably, the tilt angle is adjustable between +10/−25 about 0 and −15° relative to horizontal. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a perspective view of a shelf adjustment mechanism for an adjustable support for keyboards and the like embodying the present invention; 
         FIG. 2  is a top view of a shelf adjustment mechanism for an adjustable support for keyboards and the like embodying the present invention; 
         FIG. 3  is a cross-sectional view of the shelf adjustment mechanism of  FIG. 2  taken along line  200 - 200 ; 
         FIG. 4  is a perspective view of a top member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 5  is a top view of a top member for an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 6  is a side view of a top member for an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 7  is a perspective view of a pivoting member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 8  is a side view of a pivoting member for an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 9  is a top view of a pivoting member for an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 10  is a perspective view of a first slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 11  is a top view of a first slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 12  is a front view of a first slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 13  is a side view of a first slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 14  is a side view of an assembly of a top member, a pivoting member and a first slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 15  is a side perspective view of an assembly of a top member, a pivoting member and a first slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 16  is a rear perspective view of an assembly of a top member, a pivoting member and a first slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 17  is a perspective view of a second slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 18  is a front view of a second slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 19  is a side view of a second slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention; 
         FIG. 20  is a top view of a second slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention taken along line  20 - 20 ; 
         FIG. 21  is an exploded perspective view of a second slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention and a slot insert; 
         FIG. 22  is a rear perspective view of a second slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention and a slot insert; 
         FIG. 23  is an exploded perspective view of a second slotted member of an auxiliary shelf mounting surface for an embodiment of the present invention and an alternative slot insert; 
         FIG. 24  is a rear view of an assembly of a top member and a pivoting member of a preferred embodiment of an adjustment mechanism of the present invention; 
         FIG. 25  is a perspective view, taken from below and behind, showing an assembly of a top member and a pivoting member of a preferred embodiment of an adjustment mechanism of the present invention; 
         FIG. 26  is an enlarged view of the portion of  FIG. 25  designated by circle B; 
         FIG. 27  is a top view of a molded washer useful in a preferred embodiment of the present invention; 
         FIG. 28  is a side view of a molded washer useful in a preferred embodiment of the present invention; 
         FIG. 29  is a perspective view of a molded washer useful in a preferred embodiment of the present invention; 
         FIG. 30  is a cut-away view of the molded washer of  FIG. 27  taken along line A-A; and 
         FIG. 31  is a rear view of a molded washer useful in a preferred embodiment of the present invention. 
         FIG. 32  is a perspective view of a shelf adjustment mechanism with an auxiliary shelf for an adjustable support for keyboards and the like embodying the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in  FIG. 1 . However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. Additionally, unless the context requires otherwise, similarly numbered parts in the several drawings are intended to correspond. 
     Turning to  FIG. 1 , the adjustable support mechanism  100  to which the shelf adjustment mechanism of the present invention can be incorporated includes substantially any conventional adjustable support mechanism. For instance, the adjustable support mechanism could be any of the three dramatically different styles exemplified by the parallelogram linkage of Hannah et al. (U.S. Pat. No. 4,826,123), the four-bar non-parallelogram trapezoidal linkage of McConnell (U.S. Pat. No. 5,257,767), or my five-bar mechanism including a slider joint (U.S. Pat. No. 5,924,664). 
       FIG. 1  also shows knob  120  which moves bar  160  within slot  130 . Slot  130  is situated in the top surface of box member  150 . Box member  150  is attached to platform support  110 , and in turn pivotal member  140 . 
       FIG. 2  provides a top view of a preferred embodiment of the adjustment mechanism of the present invention.  FIG. 2  thus shows knob  120  which moves within slot insert  130  from above. Slot insert  130  is situated in the top surface of box member  150  and is generally of a diagonal orientation. In the embodiment of the present invention illustrated in  FIG. 2 , the slot insert  130  (and thus the corresponding slot) is much closer to point  210  on the front surface of box member  150  that slot insert  130  (and thus the corresponding slot) is to point  220  on the front surface of box member  150 . 
     Again, in  FIG. 2 , box member  150  is preferably welded to platform support  110 . 
       FIG. 3  provides a cross-sectional view of the mechanism of  FIG. 2  taken along line  200 - 200 .  FIG. 3  reveals that knob  120  is mounted on bar  160 . This mounting is secured by mounting means  315 , which typically can be a screw, a rivet, an adhesive, or any other conventional mechanical or chemical means of securing two components, or alternatively, knob  120  can be an integral structure of bar  160 . 
     Also seen in  FIG. 3  is the support connecting member  360  which is joined to support  100  (not shown in this FIG.) by pivot axes that pass through apertures  350  and  355 . Pivotal member  140  is also connected to support  100  by the pivot axis that passes through aperture  350 . Mounted on top of pivotal member  140  is support member  110 . 
     Bar  160  runs from knob  120  through slot insert  130  in box member  150 , through slot insert  340  in support connecting member  360 , and to pivot connection  300  which connects bar  160  pivotally to support connecting member  360 . In a particularly preferred embodiment of the present invention, bar  160  is separated from support connecting member  360  by a washer  320 . It is further preferred that washer  320  is fabricated from a plastic such as palycarbonate so as to provide a frictional resistance to the movement of bar  310 . 
     Also shown in  FIG. 3  is a spring member  330  which generally urges the support platform assembly into a preset neutral position. Desirably, spring member  330  has sufficient force to resist the deformation caused by placing an average weight keyboard on the auxiliary platform without pushing the keyboard into the steepest negative keyboard angle that can be achieved by the mechanism. 
       FIG. 4  shows the top perspective of platform support  110  and flanges  400 , which flanges were concealed in  FIG. 1  whereas  FIG. 5  shows the top view of, and  FIG. 6  shows a side view of, platform support  110 . 
       FIG. 7  shows the top perspective of pivotal member  140  and apertures  350  on each side of pivotal member  140  for pivotally mounting pivotal member  140  to support connecting member  360 .  FIG. 8  shows the side view of, and  FIG. 9  shows a top view of, pivotal member  140 . 
       FIG. 10  provides a prospective view of a preferred embodiment of box member  150  with slot  1030  into which slot insert  130  is to be placed.  FIGS. 11 ,  12  and  13  show, respectively, a top, front and side view of box member  150 , and in  FIGS. 11 and 12 , slot  1030 . Also visible in  FIGS. 10 ,  11 ,  12  and  13  is foot member  1050  of box member  150 . 
       FIGS. 14 ,  15  and  16  show, respectively a side, top perspective and rear perspective view of an assembly including platform support  110 ; pivotal member  140 , and box member  150 . Note that foot member  1050  of box member  150  sits below platform support  110 . 
       FIGS. 17 ,  18 ,  19  &amp;  20  show various aspects of support connecting member  360 . Specifically,  FIG. 17  shows a prospective view of support connecting member  360  and illustrates left and right flanges  1750  having apertures  1720  &amp;  1730  which admit pivot axes that connect support  100  to the shelf adjustment mechanism of the present invention in this embodiment.  FIG. 17  further shows slot  1710  and apertures  1740  through which the upper and lower slot inserts are connected. 
       FIG. 18  shows a frontal view of support connecting member  360  with left and right flanges  1750  as well as slot  1710  and apertures  1740 .  FIG. 19  shows a side view of support connecting member  360  with a side flange  1750  having apertures  1720  &amp;  1730 . 
     In the embodiment of the present invention illustrated in  FIGS. 17 &amp; 18 , slot  1710  is substantially parallel to the front edge of support connecting member  360  so that the shortest distance between slot  1710  and point  1760  on the front edge of support connecting member  360  is substantially the same distance as the shortest distance between slot  1710  and point  1770  on the front edge of support connecting member  360 . 
       FIG. 20  is a view taken along line  20 - 20  in  FIG. 19  and provides a top down view of connecting member  360  with left and right flanges  1750  as well as slot  1710  and apertures  1740 . 
       FIGS. 21 ,  22  &amp;  23  show connecting member  360  and the placement of slot inserts  340  into slot  1710  in connecting member  360 . These figures also illustrate side flanges  1750  and their associated apertures  1720  &amp;  1730 . 
     In the operation of the embodiment of the present invention illustrated in  FIGS. 1-23 , the movement of knob  120 , and thus bar  160 , toward point  170  of  FIG. 1  causes box member  150  to move toward point  190  relative to support connecting member  360 , which is under box member  150 . This motion of box member  150 —which shortens the distance between bar  160  and support member  110 —effectively lifts the front edge of support member  110  and increases any “negative angle”. Conversely, the movement of knob  120 , and thus bar  160 , toward point  180  of  FIG. 1  causes box member  150  to move away from point  190  relative to support connecting member  360 , which is under box member  150 . This motion of box member  150 —which lengthens the distance between bar  160  and support member  110 —effectively pushes the front edge of support member  110  down, thereby decreasing the “negative angle” of the mechanism. 
     The motion of bar  160  between points  170  and  180  in  FIG. 1  causes knob  120  to travel in an arc. In an alternative embodiment of the present invention, knob  120  is replaced with a cover mechanism that slides along the top surface of box member  150 . Desirably, this cover mechanism can accommodate the variable amount of bar  160  that projects above the top surface of box member  150  and thus this cover mechanism increases or decreases the “negative angle” of the support shelf without moving the cover mechanism out of contact with the top surface of box member  150 . 
     In a further embodiment of the present invention bar  160  with its anchor  300  is replaced with a slide mechanism that travels in the slots. Desirably, the slide mechanism is substantially I shaped having a bottom portion that is too wide to permit the slide mechanism to rise up out of the slots and a top portion that is too wide to permit the slide mechanism to sink down and out of the slots. In a more preferred version of this embodiment of the present invention, the underside of the top portion of the support connecting member  360  about slot  1710  has a track that engages the bottom portion of the slide mechanism so as to further prevent the slide mechanism from moving out of the slots. 
     Functionally this slide mechanism is substantially the equivalent of the moving bar  160  mechanism in that when the slide mechanism is moved toward point  170  of  FIG. 1 , this movement of the slide mechanism causes box member  150  to move toward point  190  relative to support connecting member  360 , which is under box member  150 . Again, this motion of box member  150 —shortens the distance between bar  160  and support member  110 —effectively lifting the rear edge of support member  110  and reducing any “negative angle”. Conversely, the movement of the slide mechanism toward point  180  of  FIG. 1  causes box member  150  to move away from point  190  relative to support connecting member  360 , which is under box member  150 . This motion of box member  150 —lengthens the distance between bar  160  and support member  110 —effectively pushes the rear edge of support member  110  down, thereby increasing the “negative angle” of the mechanism. 
     While the mechanism of the present invention can be fabricated out of substantially any conventional materials, it is believed that if slot inserts  340  are made of plastic such as polycarbonate, there is an improvement in the performance of the device of the present invention. Similarly, a performance improvement was observed when bar  160  was made of steel and coated with black oxide. Likewise, if washer  320  is made of a plastic such as polycarbonate, the frictional interaction between washer  320  and bar  160  is increased so as to substantially reduce any “spontaneous” movement of bar  160  from an extreme position toward the center of the slot. It is also desired that spring member  330  is made of spring steel. 
     It is also desired that the lower portion of slot inserts  340  in support connecting member  360  are tapered outward so as to reduce frictional contact at that point between the slot inserts and bar  160 . 
       FIG. 24  illustrates a preferred embodiment of how bar  160  is pivotally connected to the inventive mechanism at pivot connection  300 . As shown in  FIG. 24 , bar  160  projecting through slot  340  with knob  120  at its distal end. In the preferred embodiment of the present invention shown in  FIG. 24 , bar  160  is separated from support connecting member  360  by a washer  320 . 
       FIG. 25  shows pivot connection  300  from another perspective and identifies region B which is enlarged in  FIG. 26 . In  FIG. 26 , a preferred embodiment of pivot connection  300  can be seen in greater detail. Specifically, pivot connection  300 , in this preferred embodiment, includes a machine screw  2410  that communicates through spring washer  2430  (for instance, a steel spring washer), bar  160  and support connecting member  360  to lock nut  2420  and secures bar  160  to support connecting member  360 . 
       FIG. 27  provides a top view of a particularly preferred embodiment of washer  320 . In this embodiment, two parallel ridges  2450  are molded into washer  320 . Also shown in this figure is washer aperture  2440 , which is offset from the center of washer  320 . but along a line that runs through the center of washer  320 . 
       FIG. 28  provides a side view of the preferred embodiment washer  320  shown in  FIG. 27 . In  FIG. 28 , bar  160  can be seen within the valley formed by parallel ridges  2450 . 
       FIG. 29  provides a further view of the preferred embodiment washer  320  shown in  FIG. 27  from another perspective. Also seen in this view are washer aperture  2440  and parallel ridges  2450 . 
       FIG. 30  provides a cross-sectional view of washer  320  taken along line A-A in  FIG. 27 . This figure illustrates the valley formed by parallel ridges  2450  on washer  320 . 
       FIG. 31  provides a bottom view the preferred embodiment of washer  320  shown in  FIGS. 27-30 . This view shows washer aperture  2440 , which is offset from the center of washer  320 . but along a line that runs through the center of washer  320 .

Technology Classification (CPC): 0