The door was then attached to a cable from the outside that was powered by a pneumatic piston.

然后将门从外部连接到由气动活塞提供动力的电缆上。

Once the fuel has been injected into the cavity inside this cylinder, pneumatic pistons will push the metal inward (see panel 2), collapsing the cavity into a small sphere.

一旦将燃料注入该气缸内的空腔中，气动活塞就会将金属向内推（参见面板 2），将空腔收缩成一个小球体。