US Patent 7350628 High force locking spring

A spring system for relatively displacing elements attached to end mounts of the spring system. The spring system includes a housing having an axis, an internal chamber, and axially opposite bottom and top ends, a spring rod coaxial with the axis and positioned within the internal chamber and having an inner end in the housing and an outer end axially outwardly of the top end. A guide member is provided on the inner end of the rod member to support the rod member for reciprocation axially of the housing between retracted and extended positions relative thereto. A locking arrangement is provided to engage the spring rod and inhibit axial movement of the spring rod.