| 摘要 |
PURPOSE:To prevent an impacting collision between pistons by providing a needle- like protuberance on a piston and forming thereby a penetrated aperture through a free piston in order to release high-pressure substance in a gas chamber into an oil chamber when the free piston is approached to the piston abnormally. CONSTITUTION:A neelde-like protuberance 10 is provided on a piston 3. The needle-like protuberance 10 is made of a steel sheet having a L-shaped cross-section, and one side thereof is fixed to the piston 3 by means of a step 6a located under a piston rod 6 while the other side thereof is sharpened and projected downwardly from the bottom of the piston 3. When a free piston 2 is ascended abnormally, the needle-like protuberance 10 penetrates the disk of the free piston 2 and makes a penetrated aperture through which a high-pressure substance in a gas chamber A is released into an oil chamber B, and thus, an impacting collision between pistons 2, 3 may be prevented. |
