| 摘要 |
<p>A temperature control system including a pushbutton controlled, pneumatically operated actuator for controlling a vehicle heating and air conditioning system are disclosed. A plurality of pushbutton operated valve members (112) enables an operator to control the system by selectively communicating a vacuum source connected to each valve member to a given position within a vented air-piston chamber (72). A piston (74), slidably received in the chamber, is moved along the chamber by the differential pressure across the piston face until a seal member (76) located around the piston periphery blocks the orifice of the passageway (60) communicating with the vacuum source, thus substantially sealing off the chamber from the vacuum source and preventing further piston movement. The number of output positions of the actuator piston in one embodiment of the invention is equivalent to the number of pushbutton valves which communicate the vacuum source to the air chamber. Piston movement is used to control actuation of associated heating and air conditioning system components.</p> |
