Adjustable height load bearing support structure
First Claim
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1. An adjustable height load bearing support structure comprising:
- a base frame;
a generally planar support surface member;
support assembly means configured to support said support surface member for vertical movement relative to said base frame;
at least one arm biased by a spring, said spring imposing changing biasing force on said arm, said arm being pivotable about an axis disposed beneath said support surface member and having a free distal end;
said arm further having an effective moment arm; and
cam means provided at the distal end of said arm and cooperable with said support assembly means for biasing said support assembly means throughout a range of vertical travel and continuously varying the effective moment arm of said arm to compensate for the changing force of the spring biasing of said arm wherein an upward force imposed by said arm on said support assembly means is substantially constant through the range of vertical travel of said support assembly means.
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Abstract
A height adjustable load support structure has a base frame and a generally planar support surface. Preferably, two extendable vertical support assemblies support the surface for vertical movement relative to the base frame. Each support assembly is engaged by a spring biased pivotable arm to counterbalance the weight placed on the surface. A cam system cooperating between the distal ends of the pivotable arms and the support assemblies serves to compensate for the changing spring force on the arms by varying the effective moment arms of the arms thereby equalizing the force on each support assembly through its complete range of vertical travel.
51 Citations
24 Claims
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1. An adjustable height load bearing support structure comprising:
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a base frame; a generally planar support surface member; support assembly means configured to support said support surface member for vertical movement relative to said base frame; at least one arm biased by a spring, said spring imposing changing biasing force on said arm, said arm being pivotable about an axis disposed beneath said support surface member and having a free distal end;
said arm further having an effective moment arm; andcam means provided at the distal end of said arm and cooperable with said support assembly means for biasing said support assembly means throughout a range of vertical travel and continuously varying the effective moment arm of said arm to compensate for the changing force of the spring biasing of said arm wherein an upward force imposed by said arm on said support assembly means is substantially constant through the range of vertical travel of said support assembly means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An adjustable height table comprising:
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a base frame; a generally planar work surface; support assembly means configured to support opposed sides of said work surface for vertical movement of said work surface relative to said base frame; a pair of arms each biased by a spring, said springs imposing changing biasing force on said arms, said arms being pivotable about axes disposed beneath said work surface, each arm having a distal end and an effective moment arm; cam surfaces provided on the distal ends of said arms and cooperable with cam followers connected to said support assembly means for biasing said support assembly means throughout a range of vertical travel and continuously varying the effective moment arms of said arms to compensate for the changing force of the spring biasing of said arm wherein upward forces imposed by said arms on said support assembly means are substantially constant through the range of vertical travel of said support assembly means. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification