Valve system for hydraulic dampers used in swivel joints for articulated buses has proportional valve mounted in main current path, back-up valve in subsidiary current path being activated if power supply to first valve fails

摘要

The valve system for hydraulic dampers used in swivel joints for articulated buses has an electrically controlled proportional valve (30). This is mounted in a main current path (32). In the event of a failure in the power supply to this valve a back-up valve (36) mounted in a subsidiary current path (34) is activated. Independent claims are included for: (a) hydraulic vibration dampers fitted with the valve; and (b) swivel joints fitted with the dampers.