Abstract: A device and method for fastening two component members. The device includes a first component member including at least two protruded portions each having a predetermined lead angle, and a second component member which keeps predetermined positional relationship with the first component member and has at least two protruded portions which are engaged with the protruded portions of the first component member, among at least two of which protruded portions, at least one of the protruded portion has a different lead angle from the lead angle of the protruded portions of the first component member, and the first and second component members can be moved closer opposite each other, the protruded portions are engaged with each other after moving opposite each other by a certain distance, and the first and second component members are integrally fixed by frictional engagement of the protruded portions differing in the lead angle.

Abstract: Methods and apparatus for making a connection that can be rotationally locked by expansion are disclosed. Threaded tubular ends include a slot cut across a thread at a location along the circumference of the thread. Threading two tubular members that have the slot disposed in either or both of a pin or box end of the tubular members establishes the connection. The slots represent no impediment to the make-up or break-out of a box by pin connection prior to expansion. During expansion of the connection, the threads of either the box or pin end are forced via plastic flow into the slot in the corresponding thread. This results in locking the connection and preventing relative rotation between the two tubular members, which could otherwise loosen the connection.

Abstract: Exhaust system assemblies employ wire bushings for thermal compensation to minimize noise due to “stick-slip” while the system cools. In a preferred embodiment, the wire bushings are formed of at least one strand of wire coiled about male end portions of pipe sections used in the system, each of which male end portions are inserted into a female end portion and held therein by an interference fit. The strand of wire is spot welded at spaced locations to the male end portions to provide bearing surfaces between the spot welds that move slightly as the exhaust system heats and cools to relieve thermal stress in small, substantially inaudible increments.