| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a gas spring having characteristics, that is it is compact, it can produce a strong force and it can have a long use life. SOLUTION: A sleeve type gas spring in a turret index-feed type press machine incorporates an annular piston which is operatively associated with an annular piston and a reciprocating punch tool, and defines a part of an annular gas chamber for receiving a pressurized gas. When the punch tool and the piston are moved to an extended position by a ram in the press machine, the volume of the gas chamber is decreased so that the pressure in the gas chamber is increased, and accordingly, during retraction of the ram, the piston and the punch tool are moved to a retracted position by the pressure of the gas in the gas chamber. Accordingly, the contraction force of the sleeve type gas spring can be simply changed by changing the pressure of the gas in the gas chamber. Further, the gas spring has an extremely long use life, and can be simply recharged therein with gas, and a seal which is even worn out excessively, can be simply replaced with new one, thus it is possible to simply repair the gas spring.</p> |
