| 摘要 |
<p>A coupler cover (4) has a space chamber (24) defined in the inner circumference of a central opening through which a piston rod (6) of a pneumatic actuator (5) extends. The space chamber communicates to the atmosphere. Through this chamber exhaust gas from an engine liable to folw to the side of the acuator is guided to be discharged to the atmosphere. A first ring (8) and a second ring (19) are disposed in an alternately stacked relationship of one upon the other within and along the longitudinal axis of the piston rod passing opening. The first ring has a relatively small inner circumference clearance and a relatively large outer circumference clearance. The second ring has a relatively large inner circumference clearance and a relatively small outer circumference clearance.</p> |
