Abstract: The device relates to physical exercise apparatus providing variable resistance to the user has a weight stack movable along a vertical guide and a carriage movable along another guide, the guides being disposed at a predetermined angle to each other and the carriage and the weight stack being connected to each other through a rigid link. The carriage is movable by the user against a variable force dependent on the position of the weight stack in its guide, the angle between the guides and the weight of the stack.

Abstract: A tire changing machine for breaking tire beads on a wheel rim having a drop center is disclosed. The machine includes a bead breaker mechanism including upper and lower bead breaking shoes, driving levers for each of the bead breaking shoes, and horizontally and vertically adjustable mechanism for positioning the upper bead breaker, which mechanism is frictionally locked where manually adjusted. The tire changing machine also includes a rack and pinion drive arrangement for centrally located rotating tire tool driving post. The rack is driven by the upper bead breaking drive lever. Dual power cylinders are provided, one to drive the lower bead breaker drive lever and one to drive the upper bead breaker drive lever. The drive levers are driven bi-directionally by their respective cylinders. The center post is also driven bi-directionally by the upper bead breaker power cylinder.