Patent attributes
A gas spring (7) comprises a cylinder main body (20); a rod member (21) slidable to cylinder main body; a gas filled chamber (23) filled with compressed gas and urging the rod member in a first direction; a rod inserting hole (32) inserting the rod member (21); an annular collar (24) slidable on the rod member at a position apart from the rod inserting hole in the second direction opposite to the first direction; an annular groove (24a) on the annular collar which is open toward the second direction; and a lock ring (26) engaging with an annular ring mounting groove (25) on the rod member (21). In assembling, the lock ring (26) is moved in the first direction together with the rod member, to thus engage with the annular groove (24a) on the annular collar, so that the annular collar for stopping the rod member and the lock ring is stopped by an end wall of the cylinder main body.