PNEUMATIC AND HYDRAULIC POWER CONTROL OF DRILL

摘要

An apparatus and method of controlling the input power to a drill feed or other hydraulic system in which the hydraulic power source is obtained from compresssed air supply. Wherein, the flow of air is varied in response to a hydraulic signal controlled by the load demand of the hydraulic system. Low and high mode controls are provided to operate hydraulically actuated mechanisms; and a hydraulic absorbing load is imposed to prevent stall or overspeed of the pump and motor during low load conditions.