Double-acting ram sequence control system - has two auxiliary branches in each ram, past which piston travels

摘要

The sequence control system for two or more double-acting rams has a two-way valve, controlling each ram. In addition, each ram (11,12) has, two main branches (18,19,18',19') and two auxiliary ones (21,22,21',22'), past which the piston (14,14') travels. An actuator (33,33') for each two-way valve (24,25) has two setting pistons (34,35,34',35'), each separating an outer control chamber (37,39,37',39') from an inner one (38,41,38',41'), into which the end faces of a control slide (32,32') of the valve protrude. The effective cross-sectional area of the control piston is greater than the pressurised end face of the slide, and the inner and outer chambers of one valve are connected respectively to the main and auxiliary branches of the ram.