Tool step controller for large scale precision drilling machine - uses slider transmitting motion to tool carriage through double-acting hydraulic cylinder with controlled hydraulic pressure

摘要

The arrangement is used in conjunction with high precision drilling of large dia. heat exchanger plates for nuclear installations ensures that the positioning of the tool is correct, to an acceptable accuracy, before any machining operation can commence. The tool carriage is displaced by a step numerical controller. A slider mounted freely in translation relative to the base acts on a transmission link formed from a double-acting hydraulic cylinder with a pushrod which moves in the direction of translation when aligned with the slider. A detector of the presence of the slider cooperates with a bracket carried on the slider, sending an electric signal to a solenoid valve which stops the hydraulic supply. The hydraulic cylinder used is a dual piston unit with the hydraulic fluid injected at the centre.