Abstract: A coupling is provided wherein each of two members to be coupled are provided with a series of centering elements for preventing decentering of the two members during periods of thermal change. Inner and outer centering elements are provided on each member, each element having centering surfaces extending radially and transversely relative to contact surfaces of the members to be coupled. The centering elements of one member contact the centering elements of the other member only at their centering surfaces, thereby allowing for thermal expansion toward other surfaces of the elements without deformation of adjacent elements. Additional decentering arrangements are disclosed for coupling flat members. The couplings disclosed are particularly advantageous for coupling metal to ceramic.

Abstract: Apparatus for coupling multi-conduit drill pipes to maintain arcuate registry between connected pipes, and for transferring the drive torque of one drill pipe to the next drill pipe. One end of one drill pipe (50) includes drive lugs (100) matable with corresponding drive recesses (102) in the end of the next drill pipe (52). An index lug (104) in the drill pipe end, different that the drive lugs (100), is matable with a corresponding index recess (106) in another pipe end ot maintain arcuate registry of the coupled pipes and thus longitudinal alignment of the respective conduits (30) throughout the drill string. An internally threaded coupling collar (84) with different thread pitches at each end thereof is threadable onto the joined lug and recess mated drill pipe ends to hold the pipes mated. The joined pipe ends respectively include external threads (88, 90) of pitches corresponding to that of the coupling collar (84) so that a differential thread action draws the pipes together.

Abstract: A connector for engaging non-metallic liquid-tight conduit includes an inner ferrule having a cylindrical portion with an annular rib dimensioned to be inserted into the end of the conduit, and a surrounding sleeve having a conical outer surface and axially extending slots. The sleeve surrounds the conduit and is engaged by a compression nut which radially inwardly decreases the radius of the sleeve, engaging the conduit between the smaller compressed end thereof and the annular rib on the ferrule. The connector also includes a body with threads to engage the nut and the ferrule and body include means for limiting rotational motion of the ferrule.

Abstract: A connecting mechanism for pole members to surely connect the pole members together on the common axis thereof comprises a threaded member rotatably mounted on the pole member, a tubular member mounted on the other pole member rotatably and movably in the axial direction within a predetermined range, a projection from the tubular member and openings formed with the threaded member and a spring to secure the engagement of the tubular member and the threaded member.