A combination ferrule includes a ferrule portion and a holding ring portion. The ferrule portion includes a flange portion at an end of the ferrule portion. The holding ring portion includes one or more elastic projections extending coaxially from an inner wail of the flange portion. The one or more elastic projections are disposed at an angle to allow a tube enter through the holding ring and pass through the combination ferrule only in a first direction toward the ferrule portion and prevent the tube from moving in a second direction opposite to the first direction. The one or more elastic protections engage with a notch in a cavity of a compression nut such that the flange portion abuts the notch and the combination ferrule is fastened in the cavity of the compression nut.

A conduit fitting of the type having first and second threaded fitting components and at least one conduit gripping device, further includes a stroke limiting member that allows the fitting to be pulled up by applying a predetermined torque. In one embodiment, the stroke limiting member may realized as an integral or integrated load bearing member that functions as a torque collar and deflects under load. The disclosure also presents a gauging structure and method for fittings that can be pulled up by turns, by torque or both.

A compression coupling includes a sealing joint for sealingly coupling a pipe to the compression coupling and a restraining joint separate from the sealing joint for restraining the pipe to the compression coupling.

A coupling assembly for securing rigid conduits together end-to-end, or to a junction box, includes a coupling body, one or two compressible gland rings, and one or two compression nuts. The coupling body includes a first segment extending from a second segment, with an optional midsection therebetween. The compression nut threadably engages about externally-threaded coupling first and/or second segments, compressing a gland ring as it is tightened. A bend in the compression nut, and complementarily chamfers formed in the coupling body and the gland ring, may help to squeeze and compress the gland ring. The compressible gland ring is internally-threaded, and, when compressed, it bites down or grips unthreaded conduits, and its threads interlock with threads of threaded conduits. Two conduits may be secured together by rotating the coupling body and/or the compression nut of the coupling assembly without needing to rotate conduits, which can be heavy and cumbersome.

A fitting is provided that may optionally be pulled-up to its final assembled condition by torque rather than by turns. In one embodiment, at least one fitting component includes a structure that facilitates pull-up by torque. The structure may take a wide variety of different forms.

A fitting is provided that may optionally be pulled-up to its final assembled condition by torque rather than by turns. In one embodiment, at least one fitting component includes a structure that facilitates pull-up by torque. The structure may take a wide variety of different forms.

This invention relates to a surface heat treatment method in a salt bath at low temperature, suitable for partially hardening the surface of a workpiece through heat treatment, including plating the surface of a workpiece with a first metal layer; partially peeling the first metal layer; heat treating the workpiece at a temperature of 400 to 500 C. for a predetermined period of time; and totally peeling the first metal layer. Thereby, low-temperature heat treatment is effective at heat treating the workpiece while minimizing deterioration of corrosion resistance.