Actuator for ships rudder - uses rotary positive displacement motor in rotatable casing having lugs acting as crossheads

摘要

The actuating equipment is for foil surfaces, esp. ships rudders or anti-roll stabilisers, using a rotary positive displacement motor and is conventional in having a rotor (3) with 2 lobes (5) in a casing (4) also with 2 lobes (6). These create sealed spaces (7) between whose vol can be altered by the supply removal of working fluid. The casing has 2 diametrically opposed external lugs (8) acting as crossheads for hydraulic jacks (10, 11, 12). These are mounted on the ships structure so that they can be used to rotate the casing about its axis. The jacks are set to bring the casing lugs transversely of the ship. If a degree of rotation of the foil surface (up to 90 deg.) is required which cannot be achieved with the casing lobes in that position, the jacks are actuated to rotate it as necessary.