| 摘要 |
<p>A chamber formed at the lower end of a jack piston is made pressure-tight by means of a seal between the lateral walls of the piston and the jack cylinder and contains a gunpowder cartridge for actuating the jack. Two members located on each side of the pipe to be obturated by compression are intended to be driven together by firing the cartridge. One member is rigidly fixed to the jack piston and guided freely in translational motion by means of tie-bolts which serve to secure the other member to the jack cylinder.</p> |
