| 摘要 |
A gas spring for a hatch type door is disclosed, which comprises a cylinder, a piston received in the cylinder to divide the same into first and second chambers, a piston rod connected to the piston, a first device for providing a passage between the first and second chambers only when the piston moves in a direction to contract the second chamber, a second device for providing a passage between these chambers only when the piston rod is pushed against the piston by a force greater than a predetermined degree, and a third device for providing a passage between these chambers only when the piston is positioned within a predetermined area in the cylinder. |
