Pressure control and monitoring system for hydraulic machine chuck mounted on machine tool - has motorised regulator valve for double-acting cylinder and inbuilt test mode for checking pressure sensor calibration

摘要

The system for setting and monitoring the pressure exerted by the jaws (12) of the chuck has a pump (18) supplied double-acting cylinder (10) and electromagnetic reversing valve (24) for operating the jaws (12), controlled by a stepping motor (34) operated pressure regulator (22) which responds during a monitoring mode to the pressure sensors (36, 32) via a signal processing controller (50). In an alternative sensor testing mode a predetermined pressure setting signal (44) from a store data table is applied directly to the regulator (22) via the motor (34) and the sensor response checked for compliance. Sensor errors outside tolerance or system conduit/cable fractures are respectively signalled (F1, F2) by the controller (50). USE/ADVANTAGE - Has improved reliability and monitoring accuracy for minimum additional constructional expense. Sensor checking mode is largely independent of main electronics. Can be retrofitted to wide range of existing equipment.