| 摘要 |
PURPOSE:To increase repulsive force at a certain interval when compression starts, by setting up an auxiliary packing in series with a main packing, while providing a piston rod with an expanded diametral part commensurate to these packings in time of overelongation. CONSTITUTION:A stopper 21 is subjected to a roll calking 22 in series with a main packing 17 and an auxiliary packing 23 is pressed in at the right. And, a spacer 24 whose left end is of taper in form and right end is upheld by a stepped part 25 is fitted on the circumference of a piston rod 11, forming an expanded diametral part. When compression starts out of an overelongation state, a gas chamber 12a comes into a state of suction pressure from the positional relationship between the spacer 24 and the auxiliary packing 23 immediately after the start, producing suction force and thereby repulsing the piston rod 11. With this effect, repulsive force can be augmented at a certain interval when compression starts, so that it can be serviceable for accident prevention including door dropping and the like. |
