Abstract: A transport mechanism (28) is disclosed for use in a pipe bender (10) for bending pipe sections (12), particularly pipe sections having a diameter greater than one foot. First and second powered rollers (30, 32) are mounted within the pipe bender and driven by hydraulic motors to move the pipe section in a controlled manner through the pipe bender. A hold down roller (34) is pivoted against the pipe section to force the pipe section into engagement with the powered rollers to insure an adequately frictional engagement between the rollers and the pipe section to move the pipe section through the pipe bender.

Abstract: A wheel and brake assembly having a plurality of friction members moved by a pressure plate toward a backing plate to affect a brake application. Each friction member has a metallic drive ring coupled to a carbon disc. The carbon disc on a first friction member engages a portion of the drive ring on adjacent friction members to prevent the passage of air to the coupling that could degrade the carbon disc through oxidization.

Abstract: A fluid pressure actuated piston that consists of two parts, a metallic portion and a nonmetallic portion, is disposed in a conventional, metallic, cylindrical housing. The non-metallic portion is slidably engaged with the metallic housing. The metallic portion has a clearance to prevent contact with the metallic housing and is connected to the non-metallic portion in such a manner as to provide a recess for a conventional O-ring seal. The recess has metallic O-ring sealing surfaces on both the piston and the housing without any metallic contact to the housing.

Abstract: An internal pipe clamp is provided by the present invention. The clamp is designed to clamp two joints of pipe into position for a circumferential weld. The clamp includes mechanism for spacing the two joints apart a very short distance to facilitate welding. A backup member is provided which is movable from a retracted position. The backup member comprises two backup portions each of which comprises two pivotally coupled backup segments. Each segment extends through an arc of approximately 90.degree. and terminates in a wedge shaped end that is complemental to the wedge shaped end of an adjacent segment. Power cylinders move each segment from a retracted to an extended position. Power cylinders are also coupled in opposed relationship with each adjacent pair of wedge shaped ends to force same into tight contiguous relationship when the segments are extended.