Constant torque adjustable seat

Claim 1

An arrangement for lifting a load, particularly an adjustable seat, comprising a base member having a curved bearing surface; a carrier member adapted to support a load; means for mounting said carrier member on said base member for movement between a lowered position and a raised position relative to said base member; actuating means including an actuator turnable about a pivot point which is movable in a curved path in a range between first and second end limiting positions and engaging said bearing surface at different engagement points throughout said range, said curved path being spaced from said bearing surface such that the distance from said pivot point to the respective engagement point has a predetermined length when said pivot point is at said first position and a length exceeding said predetermined length when said pivot point is at said second position said actuating means being operative for moving said carrier member relative to said base member between said lowered position in which the load has a weight component of predetermined magnitude tangentially of said curved path, and said raised position in which the load has a weight component tangentially of said curved path which has a magnitude less than said predetermined magnitude; and means for orbiting said pivot point along said path between said first and second positions as said carrier member is respectively moved from its lowered toward its raised position such that each successive distance between each instantaneous position of the pivot point and the respective engagement point has a length exceeding a preceding such distance in substantially inverse proportion to the change in magnitude of the tangential weight component of the load, so that the force necessary for turning said actuator to thereby lift the load remains substantially constant during the movement of the carrier member.