Patent ID: 8342467

Claim:
A force-exerting device comprising: a force-exerting arm having: a) a load arm pivotal about a load pivot and the load arm forming a first side of a force exerting structure; the load arm having a first end attached to the load pivot and the load arm having a second end attached to a payload; b) a first end block to which the load arm is attached at the load pivot and; c) a resilient member forming a second side of the force exerting structure, the resilient member having a first end attached to the second end of the load arm and the resilient member having a second end adjustably attached to a lead screw, the lead screw being offset from vertical and being secured to the first end block; d) a line between the load pivot and resilient member second end forming a third side of the force exerting structure; e) the lead screw crossing a virtual line coincident with the plumb line, the plumb line extending through the load pivot; f) the resilient member second end adjustable along a length of the lead screw from a position above the level of the load pivot to a position below the level of the load pivot; g) a mounting sructure; h) the force-exerting arm secured to the mounting structure; and i) the mounting structure containing a pivoting single-axis connection assembly connecting the force-exerting arm to a support structure, the single-axis connection assembly pivotal about a horizontal axis to alter the angle of the virtual line so it is no longer coincident with the plumb line.