Abstract:
An adjustable keyboard support assembly including a keyboard tray support bracket; a work surface mounting bracket adapted to be coupled to a work surface; a connector mechanism having one end coupled to the work surface mounting bracket and an opposite end coupled to the keyboard tray support bracket, the connector mechanism comprising a support arm coupled to the keyboard support at an outer end, such that the keyboard tray support bracket is rotatable about a horizontal axis with respect to the support arm; an angle control mechanism between the keyboard tray support bracket and the support arm for locking the keyboard tray support bracket at a desired angular inclination with respect to the support arm, the angle control mechanism including a spring exerting a clamping pressure on the support arm and the keyboard tray support bracket and a spring lifter for repositioning the spring so as to relieve the pressured applied to the support arm and the keyboard tray support bracket; and a lever control bar coupled to the keyboard tray support bracket and the spring lifter for actuating the spring lifter to permit adjustment of the keyboard tray support bracket with respect to support arm. The lever control bar is pivotally mounted to the keyboard tray support bracket, and is substantially co-extensive with a front edge of the keyboard tray such that the keyboard support assembly may be repositioned using one hand.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U. S. Provisional Application No. 60/105,886, filed Oct. 27, 1998. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to adjustable keyboard support mechanisms. In one of its aspects, the invention relates to an adjustable keyboard support mechanism for selective adjustment of an angular orientation and/or height of a keyboard tray by manipulating a single control lever. In another of its aspects, the invention relates to an adjustable keyboard support mechanism for single-handed selective adjustment of the height and/or angular position of a keyboard tray. 
     BACKGROUND OF THE INVENTION 
     A number of keyboard support mechanisms have been developed for supporting a computer keyboard on the underside of a work surface. One such device is shown in FIGS. 1-9 to which reference is now made. 
     An adjustable keyboard support mechanism  10  including a keyboard support  15  coupled by a connector mechanism  18  to a work surface mounting mechanism  20  that is removably coupled to the underside  24  of a work surface  14 . The keyboard support  15  provides the supporting surface for a keyboard, and includes a keyboard tray support bracket  16 . The keyboard tray support bracket  16  includes a flat plate  26 . Preferably plate  26  is a stamped metal component, and includes a plurality of openings  27 . Plate  26  also includes vertical flanges  28 , which extend downwardly at opposite side edges of the plate  26 . Flanges  28  include aligned openings  126  formed in an upper portion near the rear of flanges  28  and aligned arcuate slots  130  positioned below openings  126 . 
     Keyboard tray  31  includes two slidable plates  40  and  41 . Plate  40  is a substantially rectangular member, and includes a front edge  33  that supports at least one upwardly extending tab  32  and a downwardly extending tab  38 . The front edge  33  also supports an outwardly extending arm  37 . Plate  40  also includes a top surface  39  that defines a pair of axially extending slots  49  and an axially extending slot  44  positioned between slots  49 . Additionally, side edges  46  of plate  40  support a downwardly extending, inwardly facing C-shaped flange  48 . 
     Plate  41  includes a top surface  39 ′ that defines a plurality of openings  46 . The rear edge  35  of plate  41  supports flange  34 , wherein flange  34  defines a central opening  169 . 
     To assemble plates  40 ,  41 , plate  41  is slidably received in C-shaped flange  48 . The plates  40 ,  41  are fastened together by a bolt clamp mechanism  43  that fits into slot  44  and screws  47  that are received in openings  47 ′. An adjustment knob  45  screws onto bolt  42  received in slot  44  to clamp or release plates  40 ,  41  for adjustment. The positions of the plates  40 ,  41  may be adjusted to fit different keyboards. 
     Turning now to a discussion of work surface mounting mechanism  20 , work surface mounting mechanism  20  couples keyboard support  15  to work surface  14 . A carriage  60  is slidably mounted in a track  50  mounted on the underside of work surface  14  by means of fasteners  52 , as illustrated in FIG.  5 . Track  50  has a central plate  54  that abuts the underside of work surface  14 , with inwardly facing C-shaped flanges  56  on each side of central plate  54 . Flanges  56  define opposed slots  58  that receive and hold carriage  60  for inward and outward slidable movement with respect to work surface  14 . 
     Carriage  60  includes a work surface mounting bracket  61  having a central horizontal plate  62  having downwardly extending flanges  64  on opposite lateral sides thereof. Flanges  64  include aligned openings  113  located at an upper forward end and aligned openings  159  also formed in the forward end, but at a position below openings  113 . 
     A slide mechanism  66  is carried by plate  62 . Slide mechanism  66  comprises a central plate  68  that abuts plate  62  and raised side flanges  70  that are spaced above plate  62  and extend outwardly from plate  68 . Side flanges  70  fit in slots  58  of track  50  and guide the rear support for linear movement in a forward and backward direction with respect to work surface  14 . 
     Slide mechanism  66  is mounted in track  50  by a plurality of slidable bearing members  80 , shown in detail in FIGS. 6 and 7. Bearings  80  contact surface of track  50  and provide the surface upon which slide mechanism  66  contacts track  50 . 
     Bearings  80  comprise elongated strips of tough flexible plastic material, preferably having a low coefficient of friction. The strips form upper and lower bearing surfaces in the form of V-shaped ridges  88  spaced laterally apart on the upper and lower surface thereof, as illustrated in FIG.  7 . Ridges  88  provide a reduced contact bearing surface for engagement with upper and lower surfaces of adjacent slots  58 . Bearings  80  are positioned at the four corners of slide mechanism  66  and do not extend the length of flanges  70 . 
     The strips of bearing material  80  fit through slots  82  at the front and rear edges of each slide member  66 . The strips have mating latch members  84  and  86  on the ends at an inner side thereof to permit the strips to be installed and replaced on slide member  66 . Latch members  84 ,  86  form a clip mechanism  87  that can be mechanically engaged. Clip mechanism  87  has a lip on a lower edge that extends outwardly which engages a lip that extends inwardly from an upper edge. When installed, clip mechanism  87  does not become easily disengaged and generally requires that latch members  84 ,  86  be broken for removal. This prevents bearing  80  from inadvertently coming off during use. One advantage of bearing members  80  is that they provide a minimal surface contact area for maximum slip and are easily replaced when worn out. 
     Slide mechanism  66  is mounted on plate  62  of work surface mounting bracket  61  by a central pivot bolt  90 . Pivot bolt  90  permits pivotal movement of keyboard support  15  and bracket  62  about a vertical axis defined by the axis of bolt  90 . The manner in which these members are connected together permits rotation of keyboard support  15  in a smooth manner that provides just enough resistance to rotation to maintain keyboard  12  in the position to which it is moved. 
     As shown in FIGS. 8 and 9, pivot bolt  90  is a socket head bolt. Pivot bolt  90  fits through an opening  92  in plate  68 , and in opening  63  in plate  62 . The head of pivot bolt  90  is spaced from plate  68  by a low friction Nylon washer  94  or similar material. The underside of plate  68  engages a circular Nylon plate  96 , which in turn bears against upper plate  62  of work surface mounting bracket  61 . An annular rib  98  extends downwardly from plate  68  (or it could alternatively be formed in disk  96 ) so as to minimize the surface contact between slider plate  68  and disk  96 . Another nylon washer  100  is positioned between disk  96  and slider plate  68 . A steel washer  102  is positioned on the outside of plate  62 , and a nut  104  is threaded on the end of pivot bolt  90 . Nut  104  is carefully tightened with a torque wrench until there is just enough rotation resistance to maintain keyboard  12  in a desired rotational position. Once pivot bolt  90  is sufficiently tightened, the end of pivot bolt  90  is flared with a center punch to provide an enlarged portion  106  that locks nut  104  in its desired position. Nut  104  can be a lock nut having a nylon insert or the like in order to provide additional resistance to undesired rotation of nut  104 . 
     If inward and outward sliding of keyboard tray  31  is not required, slider mechanism  66  and track  50  can be eliminated, and work surface mounting bracket  61  may be attached directly to the underside of work surface  14 . 
     Turning now to a discussion of connector mechanism  18 , connector mechanism  18  interconnects work surface mounting mechanism  20  and keyboard support  15 . Connector mechanism  18  includes a support arm  110 , as best shown in FIGS. 2 and 9, which is pivotally coupled at an inner end  108  to work surface mounting bracket  61 . At opposite end  109 , support arm  110  is pivotally coupled to tray support bracket  16 . This coupling arrangement allows support arm  110  to rotate about a horizontal axis that runs transverse to support arm  110 , thus permitting support arm  1   10  to be pivoted upwardly and downwardly to raise and lower the height of keyboard tray support bracket  16 . 
     Support arm  110  includes a flat central plate  112  having an opening  164  located adjacent a front edge  107 . Opening  164  acts as a passthrough for guiding keyboard cable  166  and/or mouse cable  168  to a position at the rear of the keyboard support  15 . 
     Support arm  110  also includes vertical flanges  114  that extend downwardly from the outer side edges  111  of central plate  112 . It will be appreciated that central plate  112  and flanges  114  may be integrally formed or constructed as separate components. Flanges  114  define aligned openings  115  at a rear edge  121  thereof. At a front edge  123 , flanges  114  extend outwardly beyond the end of central plate  112  to form a mounting flange  117  for attaching support arm  110  to keyboard tray support bracket  16 . 
     Mounting flanges  117  are triangularly shaped members having upper ends  118  that form aligned openings  120  therein, and wider lower ends  152  defining arcuate slots  124 , with the center of arc of slot  124  being the axis of the respective opening  120 . 
     To assemble connector mechanism  18  to work surface mounting mechanism is  20 , flanges  114  fit closely between flanges  64  of work surface mounting bracket  61 . Flanges  114 ,  64  are bolted or riveted together using pivot pin  116 , which extends through openings  113  and  115  in flanges  64  and  114 , respectively. Caps  119  snap onto the ends of pivot pin  116  to hold pivot pin  116  in position. A torsion spring  127  mounted on pin  116  biases support arm  110  upwardly. The bottom portions of flanges  64  are coupled to lock arms  150  by a pivot pin  158  inserted through aligned openings  159  of flanges  64  and  152  of lock arms  150 , respectively. 
     To assemble connector mechanism  18  to tray support bracket  15 , flanges  114  and  28  are coupled together. To prevent flanges  117  and  28  from wearing against one another, a friction reducing gasket  145  is positioned between flanges  28  and flanges  117 . Gasket  145  has an opening  147  in an upper portion that aligns with opening  120  of flanges  117  and a square opening  148  in a lower portion that aligns with slots  124 ,  130  of flanges  117 ,  28 , respectively. The square opening  148  retains a square head  134 ′ on bolt  134 . Another round hole  149  in a bottom portion of the gasket  145  is aligned with the square opening  148  and receives the shaft of bolt  134 . 
     In coupling flanges  117  and  28  together, pivot pin  122  extends through openings  146  and continues through aligned openings  120 ,  126  of flanges  117 ,  28 , respectively. Pivot pin  122  pivotally mounts keyboard tray support bracket  16  to support arm  110 , and is held in place by end caps  132 , which snap onto the ends of pivot pin  122 . 
     At the opposite end, arcuate slots  124  of flanges  117  align with arcuate slots  130  in side flanges  28 , with arcuate slots  130  being shorter than arcuate slots  124 . A tube  136  is positioned between arcuate slots  124 ,  130 , and bolt  134  extends through arcuate slots  124 ,  130 , tube  136  and washers  138  and through gaskets  145  and holes  154  of lock arms. Bolt  134  continues through a second tube  140  and washers  142  located on the opposite side of keyboard tray support bracket  16  where the threaded end  146  of bolt  134  engages keyboard adjustment knob  144 . 
     Adjustment knob  144  threads onto threaded end  146  of bolt  134  so that rotation of knob  144  in one direction tightens bolt  134  and clamps flanges  28  and  117  together and gaskets  145  and lock arm holes  154  so as to prevent rotation. When knob  144  is released, keyboard tray support bracket  16  is free to pivot about the axis of pivot pin  122 , openings  120 ,  126  of flanges  117  and  28 , respectively. This construction makes it possible to have adjustment knob  144  on either one or both sides of keyboard tray support bracket  16 . 
     The foregoing construction provides the connection between work surface mounting bracket  61  and keyboard tray support bracket  16 , and also provides for inclination adjustment of keyboard tray support bracket  16  with respect to connector mechanism  18 . In order to secure connector mechanism  18  at any given rotational position for a desired keyboard height elevation, a pair of locking arms  150  extend between work surface mounting bracket  61  and keyboard tray support bracket  16  at a position below and in contact with a lower edge  152  of flanges  114 . Locking arms  150  are elongated elliptically shaped members having ends  156  and  162 . End  156  includes an opening  152 , and opposite end  162  includes an opening  154 . 
     Ends  156  are brought into contact with the sides of side flanges  114  of support arm  110 . Ends  156  are also pivotally mounted to flanges  64  of work surface mounting bracket  61  by means of pivot pin  158  that extends through openings  159  in flanges  64 , which are aligned with openings  152  in arms  150 . Caps  160  are mounted onto the ends of pivot pin  158  to hold pivot pin  158  in place. 
     Opposite ends  162  of locking arms  150  receive bolt  134  therethrough. Ends  162  traverse freely along slots  124  and  130  until locked in place at a desired location in slots  124 ,  130  by tightening keyboard tray support bracket adjustment knob  144 . When locking arms  150  are locked, arms  150  serve the purpose of locking support arm  110  at a desired rotational position. 
     When locking arms  150  are assembled with support arm  110 , work surface mounting bracket  61  and keyboard tray support bracket  16 , it is necessary that locking arms  150  slide past side brackets  114  of support arm  110 . To permit this to happen, a washer  172  (FIG. 6) is positioned between flanges  114  and  64 . This permits locking arms  150  to pivot upwardly adjacent flanges  114  on the inner side thereof as the keyboard is raised and lowered. 
     In operation, keyboard tray support bracket  16  and keyboard  12  can be raised and lowered by releasing adjustment knob  144  (which releases locking arms  150 ) and thereafter raising or lowering keyboard tray support bracket  16  to its desired elevation. For instance, when the elevation of keyboard tray support bracket  16  is selected, keyboard tray support bracket  16  is rotated to the inclination desired and adjustment knob  144  is tightened. Tightening adjustment knob  144  locks the inclination of keyboard tray support bracket  16  and the height of keyboard tray support bracket  16 . When keyboard tray support bracket  16  is locked in position, slider mechanism  66  permits keyboard tray support bracket  16  to be pushed inwardly and outwardly with respect to work surface  14 . Additionally, keyboard tray support bracket  16  may be pivoted in a horizontal direction about the axis of bolt  90 . As will be appreciated, the user must hold the keyboard tray with one hand, rotate the adjustment knob  144  with the other hand to relieve the frictional clamp between flanges  28  and  117 , adjust the keyboard support with the one hand and then tighten the adjustment knob  144  with the other hand to set the keyboard in adjusted position. 
     As illustrated by the foregoing discussion, prior art keyboard support mechanisms typically require tightening or loosening of one or more adjustment control knobs  144  to move keyboard tray  15  to the desired setting. Additionally, these systems generally include complex mechanical systems that include many components that are impacted upon adjustment of the keyboard support mechanism to the desired setting. 
     SUMMARY OF THE INVENTION 
     According to the invention, an adjustable keyboard support assembly comprises a keyboard tray support bracket; a work surface mounting bracket adapted to be coupled to a work surface; a connector mechanism having one end coupled to the work surface mounting bracket and an opposite end coupled to the keyboard tray support bracket. The connector mechanism comprises a support arm coupled to the keyboard support bracket at an outer end, such that the keyboard tray support bracket is rotatable about a horizontal axis with respect to the support arm. An angle control mechanism between the keyboard tray support bracket and the support arm locks the keyboard tray support bracket at a desired angular inclination with respect to the support arm. The angle control mechanism includes a spring which exerts a clamping pressure on the support arm and the keyboard tray support bracket and a spring lifter for repositioning the spring so as to relieve the pressure applied to the support arm and the keyboard tray support bracket. A lever control bar is coupled to the keyboard tray support bracket and the spring lifter for actuating the spring lifter for selective adjustment of the keyboard tray support bracket with respect to the support arm. 
     Preferably, the connector mechanism and the keyboard tray support bracket are pivotally interconnected for rotation about a horizontal pivot axis. In one embodiment, the angle control mechanism further includes a pair of spaced apart clamping plates and the spring is placed in compression between the clamping plates. The spring is preferably at least one leaf spring and preferably two leaf springs. In one embodiment, the at least one leaf spring comprises a fiber filled synthetic resin. Preferably, the fiber filled synthetic resin is a fiberglass filled polyester resin and the at least one spring is pultruded. 
     In one embodiment, the lever control bar is pivotally mounted to the keyboard tray support bracket and has an outer end that is substantially co-extensive with a front edge of the keyboard tray. 
     In another embodiment of the invention, the adjustable keyboard support assembly includes a connector mechanism mounted at one end to a work surface mounting bracket and at an opposite end to the keyboard tray support bracket for height adjustment of the keyboard tray support bracket with respect to the work surface support bracket. The connector arm comprises a support arm coupled to the keyboard tray support bracket such that the keyboard tray support bracket is vertically adjustable with respect to the support arm. 
     Further according to the invention, an adjustable keyboard support assembly comprises a keyboard tray support bracket, a work surface mounting bracket adapted to be coupled to a work surface and a keyboard tray mounted to the keyboard tray support bracket. The keyboard tray has a front edge distal from the work surface mounting bracket. A connector mechanism has one end coupled to the work surface mounting bracket and an opposite end coupled to the keyboard tray support bracket for rotation about a horizontal axis and height articulation of the keyboard tray support bracket with respect to the work surface mounting bracket. A locking mechanism is associated with the connector mechanism for selectively locking the keyboard tray support bracket at a desired articulated position with respect to the work surface mounting bracket. A release mechanism is coupled to the locking mechanism and includes a lever control bar coupled to the locking mechanism for selectively releasing the locking mechanism for selective adjustment of the height and/or angular orientation of the keyboard tray support bracket with respect to the work surface mounting bracket. 
     The lever control bar has an outer end which is substantially co-extensive with the front edge of the keyboard tray and adjacent thereto for release of the locking mechanism and for vertical and/or height adjustment of the keyboard tray with respect to the work surface mounting bracket with one hand by the user. 
     In one embodiment, the lever control bar is pivotally mounted to the keyboard tray support bracket. In addition, the locking mechanism includes at least one leaf spring and preferably two leaf springs. Further, the at least one leaf spring comprises a fiber filled synthetic resin, preferably a fiberglass filled polyester resin. In a preferred embodiment of the invention, the at least one leaf spring is pultruded. 
     Further according to the invention, an adjustable keyboard support assembly comprises a keyboard tray support bracket, a work surface mounting bracket adapted to be coupled to a work surface and a connector mechanism having one end coupled to the work surface mounting bracket and an opposite end coupled to the keyboard tray support bracket. The connector mechanism comprises a support arm mounted at one end to the work surface mounting bracket and a coupling mounting another end of the support arm to the keyboard tray support bracket for rotatable movement of the keyboard tray support bracket about a horizontal axis with respect to the support arm. An angle control mechanism between the keyboard tray support bracket at a desired angular inclination with respect to the support arm. The angle control mechanism includes a spring exerting a clamping pressure on the support arm and the keyboard tray support bracket, a spring lifter for repositioning the spring so as to relieve the pressure applied to the support arm and the keyboard tray support bracket and a lever control bar coupled to the keyboard tray support bracket and spring lifter for selective repositioning of the spring lifter for selective adjustment of the keyboard tray support bracket with respect to support arm. The level control bar is positioned parallel and proximate to an underside of the keyboard tray support bracket. 
     Further according to the invention, an adjustable keyboard support assembly comprises a keyboard tray support bracket, a work surface mounting bracket adapted to be coupled to a work surface, a keyboard tray mounted to the keyboard tray support bracket and having a front edge distal from the work surface mounting bracket, a connector mechanism having a first end coupled to the work surface mounting bracket and a second end coupled to the keyboard tray support bracket for height adjustment of the keyboard tray support bracket with respect to the work surface mounting bracket, and a locking mechanism associated with the connector mechanism for selectively locking the keyboard tray support bracket at a desired position with respect to the work surface mounting bracket. The locking mechanism includes a release mechanism coupled to the keyboard tray support bracket for selectively releasing the locking mechanism for selective adjustment of the height of the keyboard tray support bracket with respect to the work surface mounting bracket. The release mechanism includes a lever control bar having an outer end which is substantially co-extensive with and underneath the front edge of the keyboard tray, whereby a user can release the locking mechanism and adjust the keyboard tray support bracket with repsect to the work surface mounting bracket with one hand. 
     In a further embodiment, the connector mechanism is further coupled to the keyboard tray support bracket for adjustment of the keyboard tray support bracket about a horizontal axis with respect to the work surface mounting bracket. 
     In a further embodiment, the locking mechanism further comprises a leaf spring exerting opposing clamping forces between the connector mechanism and the keyboard tray support bracket. 
     In a further embodiment, the lever control bar is elongate and substantially parallel to an underside of the keyboard tray support bracket. 
     Further according to the invention, an articulated support mechanism has a first end coupled to a primary support and a second end coupled to an auxiliary support bracket for selectively positioning the auxiliary support bracket with respect to the primary support. The articulated support mechanism comprises a locking mechanism for selectively locking the auxiliary support bracket at a desired position with respect to the primary support. The locking mechanism includes a release mechanism coupled to the auxiliary support bracket for selectively releasing the locking mechanism. The release mechanism includes a lever control bar having an outer end which is substantially co-extensive with and underneath a front edge of the articulated support, whereby a user can release the locking mechanism and adjust the auxiliary support with respect to the primary support with one hand. 
     In a further embodiment, the locking mechanism is for selectively locking the auxiliary support bracket at a desired height with respect to the primary support. 
     In a further embodiment, the locking mechanism is further for selectively locking the auxiliary support bracket at a desired angular attitude with respect to the primary support. 
     In a further embodiment, the locking mechanism is for selectively locking the auxiliary support bracket at a desired height and angular attitude with respect to the primary support. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features and inventive aspects of the present invention will become more apparent upon reading the following detailed description, claims and drawings, of which the following is a brief description: 
     FIG. 1 is a perspective view of a prior art keyboard support mechanism described above; 
     FIG. 2 is a perspective view of the keyboard support mechanism shown in FIG. 1; 
     FIG. 3 is a side elevational view of the keyboard support mechanism of FIG. 2; 
     FIG. 4 is a side elevational view similar to FIG. 3, but showing the nonvisible components in phantom; 
     FIG. 5 is a sectional view taken along line  5 — 5  of FIG. 3, but showing the slide apparatus mounted on the underside of a work surface; 
     FIG. 6 is a front partial sectional view showing the manner in which the slidable carriage is mounted in the track on the underside of a work surface; 
     FIG. 7 is a perspective view showing the manner in which bearing members are mounted in the flanges of the carriage; 
     FIG. 8 is a partial enlarged sectional view showing the manner in which the work surface mounting bracket is mounted to the slider plate of the moveable carriage; 
     FIG. 9 is an exploded view showing the components of the keyboard support mechanism of FIGS. 1-8; 
     FIG. 10 is a perspective view of a keyboard support tray and mouse support tray with a keyboard support mechanism according to the invention; 
     FIG. 11 is a bottom plan view of a keyboard support mechanism formed in accordance with the teaching of the present invention, employing a lever operated control bar for releasing and clamping the keyboard tray support bracket in a desired position; 
     FIG. 12 is a side-elevational view of the keyboard support mechanism shown in FIG. 11; 
     FIG. 13 is a sectional view taken along lines  13 — 13  of FIG. 12, showing the height and inclination adjustment mechanism of the invention shown in FIG. 11 in the locked position; 
     FIG. 14 is a cross-sectional view similar to FIG. 13 of the keyboard support mechanism shown in FIGS. 11-13, showing the height and inclination adjustment mechanism in its released position; 
     FIG. 15 is a plan view of a clamping plate employed in the present invention; 
     FIG. 16 is a sectional view taken along lines  16 — 16  of FIG. 15; 
     FIG. 17 is an edge view of the clamping plate of FIG. 15; 
     FIG. 18 is a plan view of one leaf of a fiberglass spring employed in the present invention; 
     FIG. 19 is an end view of the fiberglass spring of FIG. 18; and 
     FIG. 20 is a sectional view taken along lines  20 — 20  of FIG.  13 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring, now to the drawings and to FIG. 10, in particular, a keyboard tray  30  includes a supporting surface  4  having a flat top surface for supporting keyboard  12 , a front edge  3  and a bottom surface. The front edge  3  supports a wrist rest  182  covered with a flexible padded material. The wrist rest  182  can be integrally formed with the front edge  3  or formed as a separate element. A mouse platform  180 ,  30  a flat rectangularly shaped plastic member, can be slidably mounted the keyboard platform tray  30  for movement there with through known mounting assemblies. A lever control bar  380  is mounted beneath the keyboard tray  30  for grasping by the user to adjust the angular and/or height of the keyboard tray  30  with respect to the work surface  14  in a manner which will be described hereinafter. 
     Referring now to FIGS. 11-20 a keyboard support mechanism  300  according to the invention is similar is some respects to some of the parts in the prior art adjustment mechanism described above. Most of the components of this embodiment are identical to those of described in FIGS. 1-9 and, therefore, will not be discussed in detail for the sake of brevity. Like numerals have been used to describe like parts. The principal difference between the present invention and the previously described prior art adjustment mechanism is the use of a lever-operated control bar  380  and a spring actuated angle control mechanism  358  instead of control knob  144  to reposition keyboard tray support bracket  304 . 
     As in the previously described prior devices, keyboard support mechanism  300  includes a keyboard tray support bracket  304  interconnected to a work surface mounting mechanism  302  by a connector mechanism  308 , as shown in FIGS. 10-12. Work surface mounting mechanism  302  and keyboard tray support bracket  304  have substantially the same construction as described for work surface mounting mechanism  20  and keyboard tray support bracket  16 , respectively, of the previously described prior art devices. 
     Keyboard tray support bracket  304  mounts a keyboard tray  12  and includes a tray bracket  310  having a flat upper plate  312  coupled to the underside of keyboard tray  12  by fasteners such as screws. Additionally, plate  312  includes downwardly extending side flanges  314 . Flanges  314  include an upper end having aligned openings  334  formed therein and a lower end defining an arcuate slot  316 , with the center of slot  316  being the axis of openings  334 . The flat upper plate has flanges  311  formed at a rear portion and extending downwardly. Each of the flanges  311  has an aligned opening. 
     Work surface mounting mechanism  302 , as shown in FIG. 11, includes a work surface mounting bracket  318  having an upper plate  320  and side flanges  322 , all substantially the same as in work surface mounting bracket  61  of the previously described prior art devices. Flanges  322 , like flanges  64 , include aligned openings  113  located at an upper forward end and aligned openings  159  positioned below openings  113  at the forward end. 
     Connector mechanism  308  includes support arm  324  having an upper plate  326  and side flanges  328 . Flanges  328  extend downwardly from the outer side edges of upper plate  326  and define aligned openings  115  at a rear edge thereof. At a front edge, side flanges  328  define a U-shaped indentation  333 . A cross brace  329  extends diagonally across the underside of the upper plane  326  between the side flanges  328 . 
     Additionally, a pair of mounting flanges  332  extends forwardly from the front edge of flanges  328  in the same manner as flanges  117  of the previously described prior art devices. Flanges  332  include aligned openings  334 ′ at an upper portion thereof and arcuate slots  336  at a lower portion thereof, such that the center of the arc of each slot  336  defines the axis of the respective openings  334 ′. 
     To form a subassembly comprising connector mechanism  308  and work surface mounting support  302 , openings  115  in flanges  328  are aligned with openings  113  of flanges  322 . A pivot pin  330  is inserted though aligned openings  115  and  113 . 
     To form a subassembly comprising connector mechanism  308  and keyboard tray support bracket  12 , flanges  332  and  314  are coupled together. This union is formed by assembling flanges  332  and  314  such that arcuate slots  336  of flanges  322  overlap slots  316  formed in side flanges  314  of tray bracket  310 . A pivot pin  338  extends between aligned openings  334 ,  334 ′ of flanges  314 ,  322 , respectively. This arrangement joins the top edges of flanges  332  and  314 . 
     The bottom edges of flanges  332  and  314  are coupled together by a bolt  344 , which, when tightened, secures connector  308  and keyboard support  304  together. Bolt  344  is positioned parallel to pivot pin  338  and extends through aligned arcuate openings  316  and  336  in flanges  314  and  332 , respectively. Bolt  344  includes a head  340  at one end and is fitted with a threaded nut  346  at the other end. 
     To prevent flanges  332  and  314  from wearing against one another, a friction reducing fiber gasket  352  can be placed over the inner surface of each flange  332 . Gasket  352  is substantially the same as fiber gasket  145  of the previously described prior art adjustment mechanism, and includes spaced openings therein that align with openings  316  and  334  of flange  314  upon installation. When the assembly is completed, openings  334  and the respective gasket opening receive pivot pin  338 , and slots  316  and the respective gasket opening receive bolt  344 . The fiber gasket  352  can be eliminated if desirable. 
     The opposite side of each gasket  352  abuts a locking arm  348  such that gasket  352  is sandwiched between flanges  314  and locking arms  348  at the inwardly facing surfaces of tray bracket  310 . Locking arms  348  are substantially the same as locking arms  150  of the previously described prior art devices, and are pivotally coupled to work surface mounting bracket  318  by means of a pivot pin  350  at one end of locking arm  348 . The other end of each locking arm  348  includes openings therein that align with slots  316 ,  336  of flanges  314 ,  332 , respectively, and through which bolt  344  is received. 
     The foregoing discussion describes the connection between work surface mounting support  302 , connector mechanism  308  and keyboard tray support bracket  304  and the manner of assembling the described components. An angle control mechanism  358  for adjusting the height and inclination of keyboard tray support bracket  12  with respect to supporting arm  324  of connector mechanism  308  will now be described. Angle control mechanism  358  includes a pair of clamping plates  360 , a pair of leaf springs  370 , spring lifter  371  and a lever control bar  380 . 
     As shown in FIGS. 13-14, clamping plates  360  are positioned adjacent side flanges  332  of support arm  324 . Clamping plates  360  are preferably formed of 10-20% glass fiber filled nylon, and each comprises essentially a rectangular flat plate  356 . Flat plate  356  forms a groove  362  at an upper end  367  that receives a bottom portion of pivot pin  338  and a groove  364  at a lower end that receives the upper portion of bolt  344 . Flat plate  356  also defines recesses  366  in the inner surfaces of the upper portion of clamping plates  360  for receiving the ends of leaf spring  370 . Below recesses  366 , flat plate  356  includes recesses  368  formed in the inner surfaces of the lower portion of clamping plates  360 . An outwardly extending projection  372  is located on flat plate  356  between recesses  366  and  368  and defines a retaining shoulder  363  with recess  368 . Additionally, clamping plates  360  include a lower edge  369  having an inclined surface  373  that forms a thirty-degree angle relative to lower edge  369 . 
     The leaf spring  370  is a flat resilient plate, and is positioned in compression between clamping plates  360  and seated in shoulder  363  such that the ends of spring  370  apply an outward clamping force to each plate  360 . It will be appreciated that other types of clamps can be used to provide the clamping function of leaf springs  370 . Preferably two leafs springs are used for the clamping function although it is within the scope of the invention to use a single leaf spring or more than two leaf springs. The number of leaf springs will depend on the clamping force desired and the thickness of the leaf springs. In a preferred embodiment, each of the two leaf springs  370  has a thickness of approximately 0.067 inches, a width of approximately 0.73 inches and a length of 3.4 inches. The leaf springs  370  is made of a fiber filled synthetic resin. In a preferred embodiment, the leaf spring  370  can be made of a fiberglass filled polyester resin and formed by a pultrusion process, for example, described in U.S. Pat. Nos. 4,983,453, 5,585,155, 4,154,634 or 5,324,377. Pultruded products are available from POLYGON Company of Walkerton, Ind. 
     As shown more clearly in FIGS. 13,  14  and  20 , spring lifter  371 , as the name implies, imparts a lifting force on springs  370 . Spring lifter  371  includes a central web  372  which is connected at an upper end to an arcuate retainer  397  and at a lower end to a yoke  374 . The ends of the yoke  374  have aligned openings which receive a pin  375  which extends below the springs  370 . 
     To install angle control mechanism  358 , the pin  375  is inserted through the aligned openings in the yoke  374  and beneath the spring  370 . Each end of spring  370  abuts in recesses  368  of the clamping plates  360  and abuts shoulder  363  of clamping plates  360 . The shoulders  363  hold the ends of spring  370  in abutting relationship with clamping plates  360  between projection  372  and bolt  344  positioned. 
     As shown in FIGS. 13-14, the distance between clamping plates  360  when installed between side flanges  328  of bracket  318  is less than the length of spring  370 , thus requiring spring  370  to be resiliently bowed when installed. Since spring  370  is resilient and is deflected when installed, spring  370  exerts an outward pressure against inclined surface  373  of clamping plates  360 . Clamping plates  360  in turn press side flanges  328  of support arm  324  against locking arms  348  and against fiber gasket  352  and, thus, against side flanges  314  of tray bracket  310 . This arrangement, together with the clamping pressure supplied by bolt  344 , resiliently clamps the various components together and holds keyboard tray  12  at the desired height and inclination. The characteristics and dimensions of spring  370  are selected so that the components are held in position securely when the ends of spring  370  press against flanges  314  and  328 . 
     As shown in FIG. 13, when handle base  384  is in a lower position relative to pivot pin  338 , spring  370  exerts pressure against clamping plates  360  to clamp the keyboard tray in an adjusted position. When, however, handle base  384  is lifted upwardly (as shown in FIG. 14) so that the arcuate retainer  397  contacts pivot pin  338 , the pin  375  of the spring lifter  371  moves upwardly to raise the central portion of springs  370  to increase the bow in the springs  370 . This action pulls the ends of spring  370  and clamping plates  360  inwardly, relieving the clamping pressure of clamping plates  360  against the mounting flanges  332 , locking arms  348  and side flanges  314 . When the pressure is relieved, keyboard tray  12  is released for adjustment in height and inclination with respect to the work surface  14 . 
     Spring lifter  371  is actuated by means of a lever control bar  380  positioned under keyboard tray  12 . Lever control bar  380  includes an outwardly projecting handle  382  that extends substantially co-extensively with the outer edge of keyboard tray  12 , such that the end of handle  382  extends just short of the outer edge of keyboard tray  12 . Lever control bar  380  also includes a handle base  384  having upstanding side flanges  386  that have enlarged openings  387  for receiving pivot pin  338 . The diameter of the openings  387  are somewhat larger than the outer diameter of the pivot pin  338  so that the pivot pin  338  can articulate within the openings  387  when the lever control bar  380  is lifted. The side flanges  386  project rearwardly of the openings  387  at  385  and define openings  389  that are aligned with the openings in the depending mounting flanges  311  of the plate  312 . Fasteners such as rivets or pin connectors  408  are received in the openings  389  in the rearward projections  385  and in the depending mounting flanges  311  of the plate  312  for pivotally mounting the lever control bar  384  to the depending mounting flanges  311  of the plate  312 . Thus, the lower control bar  380  is pivotally mounted on the pins  408  and for pivotal movement with respect to tray bracket  310 . 
     Handle base  384  also forms an arcuate transverse depression  391  at a rear portion and includes a rectangular opening  393  at a rear end for receiving the central web of spring lifter  371 . The arcuate retainer  397  is cradled in the arcuate transverse depression  391  and passes through the rectangular opening  393  when rotated 90° about a vertical axis from the position shown in FIGS. 13,  14  and  20 . The arcuate retainer  397  pivots within the transverse depression  391  as the angular relationship between the handle base  384  and the connector mechanism  308  changes. As the keyboard support tray  12  rotates about the pivot pin  338  with respect to the connector mechanism  308 , the handle base  384  moves with the keyboard support tray  12 . Thus, the angular relationship between the handle base  384  and the spring lifter  371  changes. However, the relationship between the spring lifter  371  and the leaf spring  370  remains constant. Because of the arcuate shape of the transverse depression  391 , the handle base  384  can rotate about the pivot pin  338  as well. Thus, the mechanical relationship between the handle base  384  and the spring lifter  371  remains constant regardless of the angular relationship between the keyboard support tray  12  and the connector mechanism  308 . This functional relationship is an important feature of the invention because it achieves the desired functional relationship with simple, stamped mechanical parts and does need to require expensive cable or other indirect connections which lose efficiency through multiple links. 
     The lever control bar  380  terminates at an outer end in an enlarged loop  404 . An oval handle pad  405  having a grooved central portion covers loop  404 . Handle pad  405  provides a comfortable handle grip for actuating lever control bar  380 . Handle pad  405  can be adapted to receive or to be imprinted with various indicia. 
     To adjust tray support bracket  15 , a user can grasp the handle  382  and the outer end of the keyboard tray  12  in one hand and squeeze the handle  382  toward the keyboard tray  12 , thereby releasing the clamping pressure on the adjustment mechanism. The keyboard  12  can then be adjusted with the same hand while holding the handle  382  against the keyboard tray  12 . When the adjustment is complete, the user simply releases the grip on the handle  382  and keyboard tray  12  to set the keyboard tray in adjusted position. 
     The upward pivotal movement of handle  382  lifts spring lifter  371  upwardly within the confines of movement permitted by the arcuate lifter surface  397  and the pivot rod  338  as illustrated in FIG.  14 . This action bends spring  370  to a more arcuate shape, which shortens the length of spring  370 , thus, relieving the pressure on clamping plates  360 . When lever control bar  380  is lifted upwardly, the release of pressure on spring  370  is sufficient to freely adjust the keyboard tray  12  with respect the work surface  14 . When handle  382  is released, spring  370  is flattens out to a certain degree. This action causes enough pressure to be exerted on the angle control mechanism  358  to resiliently clamp the components in place no matter what the tilt or height adjustment of keyboard support  15 . 
     The keyboard support mechanism  300  provide a substantial advantage over a hand-operated clamp illustrated in FIGS. 1-9, which must be screwed and unscrewed in order to adjust the components with one hand while holding the keyboard tray with the other tray. The keyboard support mechanism  300  as described herein can be manipulated using one hand to lift handle  382 . The components automatically clamp and lock the keyboard in place when handle  382  is released. The use of leaf spring  370  and spring lifter  371  for purposes of releasing and clamping the components together provides a simple, yet cost effective mechanism for accomplishing this purpose with a minimum number of parts and expense. 
     This system also provides an advantage over linkage systems in that it uses fewer parts and permits direct actuation of keyboard support mechanism  300  without the use of cabling or linkage connections such as parallelogram linkage systems. 
     There are a variety of configurations that may be employed to fabricate the adjustable keyboard support mechanism of the present invention. Thus, the disclosed embodiment is given to illustrate the invention. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the scope of the invention which is defined in the appended claims.