JACKBOLTS FOR MULTI JACKBOLT TENSIONERS

摘要

Jackbolt (20) for a multi jackbolt tensioner embodies a thread construction which tapers from a maximum diameter adjacent to the torque receiving end (22) of the jackbolt (20) when threadedly engaged with a threaded opening in the outer peripheral part of a jackbolt body (38). The threads (26) of the jackbolt have a different thread pitch than the threads (36) in the jackbolt body (38) and the tooth flank of the jackbolt threads (26) form an angle with the tooth flanks of the threads (36) in the jackbolt body (38). By this thread construction, there is formed a helical volume of ever increasing size along the jackbolt commencing at a metal to metal relation at the torque receiving end (22). Stressing of the jackbolt (20) closes the helical volume bringing the threads (26) to a metal to metal load transfer relation. The end (28) of the jackbolt (20) has a protruding central end portion that elastically flattens under stress to reduce torque requirements.