Lengthwise-adjustable gas spring

In a lengthwise adjustable, compressed-gas-filled spring comprising:

• an outer cylinder;
• an inner cylinder coaxially disposed in said outer cylinder, and defining an annular chamber therebetween;
• a piston axially displaceably mounted within said inner cylinder, said piston sealingly dividing the inside of said inner cylinder into a first and a second housing chamber;
• a piston rod connected at one end to said piston on the side facing said first housing chamber, said piston rod extending out of said cylinders in a sealed manner;
• connecting means for providing a fluid connection between said first housing chamber and the annular chamber;
• and
• valve means, operable from outside the cylinder, at the end of the cylinders opposite that from which the piston rod extends, for connecting or separating said second housing chamber from said annular chamber;
• the improvement wherein:
• said inner cylinder is axially displaceable within said outer cylinder, is sealed off at the end opposite that from which said piston rod extends, and has a passageway therethrough in the vicinity of said sealed off end;
• said spring further comprising sealing means in the vicinity of said passageway for sealing off said passageway in one axial position of said inner cylinder within said outer cylinder and for permitting access from said second housing chamber to said annular chamber through said passageway when said inner cylinder is in a second axial position within said outer cylinder,
• whereby said inner cylinder and said sealing means serve as said valve means.