摘要 |
One aspect of the invention provides a positioning system comprising at least one master ram (26, 28) and respective slave ram (22, 24), at least one travel stop (36) and at least one pressure relief valve (68). The or each travel (36) stop is arranged to restrict the travel of one or more slave piston (22, 24) when the system is misaligned, at least one pressure relief valve (68) being arranged to vent excess pressure in the operating fluid arising as a result of such restriction. The positioning system is particularly suited for incorporation into a steering system, especially for an articulated vehicle (10). |