Method and apparatus for preloading a joint by remotely operable means

Abstract

Method and apparatus for joining structures, an active structure (10) and a passive structure (12), and imposing a tensile pre-load on the joint by a remotely operable mechanism comprising a heat contractible joining element (15). The method and apparatus include mounting on the structure (10) a probe shaft (15) of material which is transformable from an expanded length to a contracted length when heated to a specific temperature range. The shaft (15) is provided with a probe head (21) which is receivable in a receptacle opening (41) formed in the passive structure (12) when the active structure (10) is moved into engagement therewith by an appropriate manipulator mechanism. A latching system (45) mounted on the structure (12) adjacent to the receptacle opening (41) captures the probe head (21) when the probe head (21) is inserted a predetermined amount. A heating coil (26) on the shaft (15) is energizable by remote control for heating the shaft (15) to a temperature range which transforms the shaft (15) to its contracted length whereby a latching shoulder (24) thereof engages latching elements (47) of the latching system (45) and imposes a tensile preload on the structural joint. Provision is also made for manually adjusting the probe head (21) on the shaft (15) to allow for manual detachment of the structures (10,12) or manual preloading of the structural joint.