Keyboard support assembly

Abstract

An articulated support assembly for a computer keyboard. The assembly includes a platform for supporting a computer keyboard. A parallelogram linkage pivotally interconnects the platform assembly to an attachment member secured to a support surface. A releasable retaining means prevents movement of the platform toward a lowered position relative to the support surface. Pivotal movement of the platform alters the distance between pivot axes of the parallelogram linkage to disengage the retaining means and allow movement of the platform toward either a lowered or a raised position relative to the support surface.

1 . An articulated support assembly adapted for adjustably supporting a computer keyboard from a horizontal support surface, the support assembly comprising: 
 an attachment member adapted to be attached to the horizontal support surface;    a platform assembly having an upper surface adapted to have a computer keyboard supported thereon, the upper surface having a predetermined orientation with respect to the horizontal support surface;    a vertically swingable parallelogram linkage having elongated first and second links each having a first end and a second end, the first ends of the elongated first and second links pivotally interconnected to the platform assembly, and the second ends of the elongated first and second links pivotally interconnected to the attachment member, such that the first and second ends of the first and second links each have a pivot axis, and such that the linkage allows vertical displacement of the platform assembly relative to the support surface while maintaining the predetermined orientation of the upper surface;    a releasable retaining means coupling the first link to the attachment member, the releasable retaining means moveable between an engaged position for preventing vertical movement of the platform assembly toward a lowered position relative to the horizontal support surface, and a disengaged position for allowing vertical movement of the platform assembly toward either a lowered or a raised position relative to the horizontal support surface; and    means for altering the distance between the pivot axes of the second link, wherein altering the distance between the pivot axes of the second link moves the releasable retaining means between the engaged position and the disengaged position.    
   
   
       2 . The articulated support assembly of  claim 1 , wherein the means for altering the distance between the pivot axes of the second link comprises an elongated through-slot at one of the first and second ends of the second link, the elongated slot configured to receive a shaft defining one of the pivot axes of the second link, the shaft movable between a first end of the slot having defining a first inter-axis distance and a second end of the slot defining a second inter-axis distance.  
   
   
       3 . The articulated support assembly of  claim 2 , wherein the shaft is movable between the first end of the slot and the second end of the slot by pivotal movement of the platform assembly about the pivot axis at the first end of the first link.  
   
   
       4 . The articulated support assembly of  claim 1 , wherein the releasable retaining means comprises: 
 a height adjustment gear having radially outwardly projecting gear teeth, the gear attached to the attachment member and coaxial with the pivot axis of the second end of the first link;    a pawl assembly attached to the first link and configured to engage the gear teeth;    a biasing member urging the pawl assembly toward the gear teeth; and    a cable attached to the pawl assembly and configured to pull the pawl assembly away from the gear teeth, the cable extending from the pawl assembly along a cable path to the second link, the cable path alterable between a normal cable path allowing engagement of the pawl assembly with the gear teeth, and a lengthened cable path causing the cable to pull the pawl assembly away from the gear teeth;    wherein altering the distance between the pivot axes of the second link alters the length of the cable path between the normal cable path and the lengthened cable path.    
   
   
       5 . An articulated support assembly adapted for adjustably supporting a computer keyboard from a horizontal support surface, the support assembly comprising: 
 an attachment member adapted to be attached to the horizontal support surface;    a platform assembly having an upper surface adapted to have a computer keyboard supported thereon;    a first support arm adapted for mounting the platform assembly on the attachment member, a first end of the first support arm pivotally mounted to the platform assembly for pivotal movement of the platform assembly about a first platform pivot axis, a second end of the first support arm pivotally mounted to the attachment member for pivotal movement about a first attachment member pivot axis;    a second support arm adapted for mounting the platform assembly on the attachment member, a first end of the second support arm pivotally mounted to the platform assembly for pivotal movement of the platform assembly about a second platform pivot axis, a second end of the second support arm pivotally mounted to the attachment member for pivotal movement about a second attachment member pivot axis;    wherein the first platform pivot axis, second platform pivot axis, first attachment member pivot axis and second attachment member pivot axis are parallel to each other, and wherein the first and second platform pivot axes, the first and second attachment member pivot axes, and the first and second support arms are positioned to define a parallelogram linkage; and    first releasable retaining means between the first support arm and the attachment member, the first releasable retaining means moveable between an engaged position for preventing rotating movement of the first support arm toward a lowered position relative to the attachment member, and a disengaged position for affording rotating movement of the first support arm toward either a lowered or a raised position relative to the attachment member;    wherein the first releasable retaining means is moved from the engaged position to the disengaged position by pivotal movement of the platform assembly about the first platform pivot axis.    
   
   
       6 . The articulated support assembly of  claim 5 , wherein the first releasable retaining means comprises: 
 a height adjustment gear having an axis and radially outwardly projecting gear teeth, the gear attached to the attachment member and coaxial with the first attachment member pivot axis; and    a pawl assembly attached to the first support arm and configured to engage the gear teeth;    wherein the first releasable retaining means is moved to the engaged position by moving the pawl assembly toward the gear and causing engagement of the pawl assembly with the gear teeth, and wherein the wherein the first releasable retaining means is moved to the disengaged position by moving the pawl assembly away from the gear and causing disengagement of the pawl assembly from the gear teeth.    
   
   
       7 . The articulated support assembly of  claim 6 , further comprising: 
 a biasing member urging the pawl assembly toward the gear; and    a cable attached to the pawl assembly and configured to pull the pawl assembly away from the gear, the cable extending from the pawl assembly along a cable path to a cable anchor in fixed relationship to the attachment member, the cable path alterable between a normal cable path allowing engagement of the pawl assembly with the gear, and a lengthened cable path causing the cable to pull the pawl assembly away from the gear;    wherein pivotal movement of the platform assembly about the first platform pivot axis alters the length of the cable path between the normal cable path and the lengthened cable path.    
   
   
       8 . The articulated support assembly of  claim 7 , wherein pivotal movement of the platform assembly about the first platform pivot axis alters the distance between the second platform pivot axis and the second attachment member pivot axis.  
   
   
       9 . The articulated support assembly of  claim 7 , wherein the cable path is altered between the normal cable path and the lengthened cable path by pivotal movement of the platform assembly about the first platform pivot axis in the range of 2 to 8 degrees of rotation.  
   
   
       10 . The articulated support assembly of  claim 5 , further comprising: 
 a third support arm adapted for mounting the platform assembly on the attachment member, a first end of the third support arm pivotally mounted to the platform assembly for pivotal movement of the platform assembly about the first platform pivot axis, a second end of the third support arm pivotally mounted to the attachment member for pivotal movement about the first attachment member pivot axis; and    second releasable retaining means between the third support arm and the attachment member, the second releasable retaining means moveable between an engaged position for preventing rotating movement of the third support arm toward a lowered position relative to the attachment member, and a disengaged position for affording rotating movement of the first support arm toward either a lowered or a raised position relative to the attachment member;    wherein the second releasable retaining means is moved from the engaged position to the disengaged position by pivotal movement of the platform assembly about the first platform pivot axis.    
   
   
       11 . The articulated support assembly of  claim 10 , wherein the second support arm is positioned between the first and third support arms.  
   
   
       12 . The articulated support assembly of  claim 5 , further comprising tilt adjustment means joining the second support arm to the platform assembly, the tilt adjustment means movable between a retaining position for limiting pivotal movement of the platform assembly about the first platform pivot axis and positioning the upper surface of the platform assembly at a predetermined orientation relative to the attachment member, and a release position affording relatively free pivotal movement of the platform assembly about the first platform pivot axis.  
   
   
       13 . The articulated support assembly of  claim 12 , wherein when the tilt adjustment means is in the retaining position, the limited pivotal movement of the platform assembly about the first platform pivot axis is sufficient to move the first releasable retaining means from the engaged position to the disengaged position.  
   
   
       14 . The articulated support assembly of  claim 13 , wherein pivotal movement of the platform assembly about the first platform pivot axis alters the distance between the second platform pivot axis and the second attachment member pivot axis when the tilt adjustment means is in the retaining position.  
   
   
       15 . The articulated support assembly of  claim 13 , wherein when the tilt adjustment means is in the retaining position, the pivotal movement of the platform assembly about the first platform pivot axis is in the range of 2 to 8 degrees of rotation.  
   
   
       16 . The articulated support assembly according to  claim 5 , wherein said first releasable retaining means comprises: 
 a height adjustment gear having an axis and radially outwardly projecting gear teeth, the gear attached to the attachment member and coaxial with the first attachment member pivot axis; and    a pawl assembly including a pivot portion and a rocking portion, the pivot portion having a first end mounted on the first support arm for pivotal movement about a pivot portion axis parallel with the first attachment member pivot axis, and a second end having an arcuate surface that is cylindrically concave about an axis parallel to the first attachment member pivot axis and faces the teeth on the gear, the rocking portion having first and second sides, a cylindrically convex surface on the first side adapted to nest in the cylindrically concave surface of the pivot portion and a plurality of teeth projecting along said second side adapted to engage between the teeth of the gear;    wherein the pivot portion and the rocking portion of the pawl assembly are oriented with the axis of the pivot portion arcuate surface below a straight line between the first attachment member pivot axis and the pivot portion axis to cause the concave surface of the pivot portion to press against the convex surface of the rocking portion and thereby engage the teeth on the rocking portion with the teeth on the gear to prevent revolving movement of the first support arm toward a lowered position relative to the attachment member, while upward movement of the first support arm relative to the attachment member causes the pivot portion to pivot and move the arcuate surface away from the gear to afford separation of the teeth on the rocking portion from the gear and afford revolving movement of the first support arm toward a raised position relative to the attachment member.    
   
   
       17 . The articulated support assembly according to  claim 16 , wherein the rocking portion has a guide surface defining a through-slot generally at the axis of the cylindrically convex surface and a side surface defining a recess along the side of the rocking portion opposite the straight line between the first attachment member pivot axis and the pivot portion axis, wherein the pivot portion includes a pin projecting through the rocking portion slot and adapted to engage the guide surface to carry the rocking portion on the pivot portion and provide a pivot axis for the rocking portion to pivot the teeth adjacent the rocking portion recess out of engagement with the teeth on the gear.  
   
   
       18 . The articulated support assembly according to  claim 17 , wherein teeth on the rocking portion opposite the recess engaged with teeth on the gear when upward movement of the first support arm relative to the attachment member is initiated, and the first support arm has a pin adapted to be engaged by the surface defining the rocking portion recess when the teeth adjacent the recess pivot out of engagement with the gear to restrict further pivoting of the teeth adjacent the recess away from the gear and cause opposite pivot motion of the rocking portion about the pins to cause the teeth opposite the recess to separate from the gear during further upward movement of the first support arm relative to the attachment member.  
   
   
       19 . The articulated support assembly according to  claim 16 , wherein the first releasable retaining means is moved to the disengaged position by pivoting the pivot portion to move the arcuate surface away from the gear and cause retraction of the teeth on the rocking portion to a position spaced from the teeth on the gear.