| 摘要 |
<p>An air suspension means for a trailer has a single valve (10) with a number of ports and a manual control member (18). In one condition of the valve (10), the conventional levelling valve (19) adjusts the suspension of the chassis/load during normal running of the trailer. Only when the trailer is stationary, a multi-position operating member (18) allows lift and lower positions to be selected in which the air bags (20, 21) are connected either to the main air supply (12) or to the exhaust port (11) respectively. An override is applied at a control port (17) to force the manual operating member (18) to the normal ride position, bringing the levelling valve (19) into operation. The control port (17) is actuated either pneumatically or electrically in response to either air pressure or electrical signal derived from applying the brakes of the trailer or by electrical signals derived from movement of the trailer wheels. The single valve (10) may have two auxiliary ports (50, 51). The first auxiliary port (50) may be a brake release port, operating to release the brakes during raising and lowering of the trailer only. The second auxiliary port (51) may be connected to the main air supply (12) only during the held condition of the trailer so as to operate a system to be used only during loading for example a suspension lock, internal lighting, tanker discharge valves or the like.</p> |
