| 摘要 |
A pneumatic spring of the piston-and-cylinder type constitutes a support column whose length may be adjusted when a valve connects the two cylinder compartments on opposite sides of the piston. The valve is normally closed by gas pressure and may be opened by a releasing rod coaxially movable in the bore of a tubular column member. An operating lever for the releasing rod passes radially through an opening in the tubular member and is coupled to the releasing rod during assembly of the apparatus by a cam face on the radially moving lever displacing the rod against the gas pressure in the cylinder, whereupon the rod drops into an axially open recess of the lever from which it can no longer be released because of the limited clearance in the column opening. |
