Abstract: An apparatus is provided for converting a pressurized air operating impulse to a hydraulic operating impulse, especially for a precision grinding machine. The apparatus comprises at least one tool support, a compressed air control system for a plurality of adjusting or positioning piston cylinder devices, and a cooling and washing fluid system. The tool support has a fed piston cylinder device which is provided with two pressurized medium inlets, one of these inlets being for the feeding and pressing on motion, the other one being for the take off motion. Two regulating chambers mounted vertically are provided with connecting members for the pressurized medium inlets of the fed piston cylinder device in the lower portion of the regulating chambers.

Abstract: The grinder, especially a high precision grinder, for a ring bearing which has a race with a curved cross section comprises at least one tool support and at least one tool holder. The tool holder is support in the tool support on two equal feed guide rods. A feed piston cylinder device for a feed and a withdrawal motion is provided. The tool support with the tool holder is oscillatable to and fro about a substantially central oscillation axis through the tool support which provides a tool mounted in the tool holder in the working position with a to and fro pivoting motion rotating substantially about the center of the curved cross section of the race. To minimize disturbing vibration the feed guide rods are held and secured at both ends by at least one crosstie bar. The crosstie bars at both ends of the feed guide bars are mass balanced in regard to the pivoting motion.