System for controlling the rotating speed of a pneumatically driven spindle

Abstract

A rotating speed control system for a pneumatically driven spindle used in a machine tool, comprises a spindle possessing a male-threaded part, a turbine mounted on the spindle by a nut with a convexo-concave portion being formed in one face thereof, a casing for accommodating the spindle and the turbine, an air supply line connected to the casing so as to supply air to drive the turbine, a valve disposed in the air supply line so as to adjust the flow rate of the air to be supplied to the turbine, a sensor facing the convexo-concave portion of the nut so as to detect the rotating speed of the turbine, and a control circuit for comparing a sensor detected rotating speed with a predetermined rotating speed and for adjusting the valve in accordance with the difference between two rotating speeds, so as to reduce the difference.

Dependencies are inferred from the claim text.