| 摘要 |
<p>The clutch includes a pulley or sheave rotatably mounted on a fixed shaft. An annular friction facing is connected to an internal surface of the sheave, and a fan blade hub rotatably mounted on the shaft adjacent the sheave. The hub has an annular piston cavity or cylinder having a piston facing the friction facing. The piston is normally urged out of contact with the friction facing by a spring. An annular thrust cap located on the side of the friction facing opposite the piston, is connected to the fan hub and out of contact with the friction facing. Passageways supply air or other fluid to the back side of the piston urging the piston into contact with the friction facing and against the thrust cap to thereby engage the fan hub with the sheave.</p> |
