Abstract: Helical isolator (I.sup.1, I.sup.2) in a turnbuckle frame (10) on a central rod (2) with connector rods (34, 36) of opposite handed threads, are for mounting between a pipe and an adjacent structure. The wire energy absorbing rope bights (32) of the isolator I.sup.1, I.sup.2 are placed in parallel planes and in a state of precompression and have bi-linear spring properties which are adjustably provided by the diameter of the structural tube (10) and spacer bars (30) attached to the tube wall (12) as part of the bases (26, 28) of the isolators.