Die cast system for control of stair climbing exercise device

Abstract

A unitized assembly for control of ram-actuated stair climbing type exercise equipment provides rigidly connected ram cylinders in a unitary structure which includes a pair of castings, in which the castings eliminate the necessity of individually mounting discrete ram cylinders while at the same time eliminating the necessity for over 20 parts as compared to piston type hydraulic systems assembled from discrete components. The top casting accommodates two rams, one for each pivoted stair step. The bottom casting includes two chambers and the passageways that connect them with the rate valve that controls exercise speed. The passageways also connect to the fluid volume valve which controls step height and lost fluid replacement. As a feature for pivoted arm machines, the tops of the rams are not pivotally attached to the stair step arms, but rather contact rollers on the arms so that the rams and associated housings need not swivel with movement of the arms during exercise. This permits the rigid connection between the ram cylinders provided by the unitary pair of castings. Moreover, an integral heat exchanger is provided, along with ports for both a rate control valve and a fluid volume valve, with the fluid volume valve and an auxiliary cylinder providing selective step height control and makeup of lost fluid. As another further feature, the rams have a larger diameter on one end to retain them in the structure.