A pump assembly includes an electric drive motor with a motor drive shaft and a rotor. The motor drive shaft extends along a rotor axis and the rotor is mechanically coupled to the motor drive shaft. A pump housing encloses an impeller that is mechanically coupled to a pump drive shaft. The pump drive shaft extends along the rotor axis. The motor drive shaft is releasably coupled to the pump drive shaft by a drive shaft coupling for transferring torque from the motor drive shaft to the pump drive shaft. The drive shaft coupling is arranged within the motor drive shaft for transferring torque from the motor drive shaft to the pump drive shaft by frictional connection. The drive shaft coupling is accessible by an elongate tool through the second axial hollow motor drive shaft drive end for selectively tightening and releasing the drive shaft coupling.

A keyless timing gear assembly for securing a bull gear to a crankshaft of a power end of a reciprocating pump assembly, the keyless timing gear assembly including at least one actuator, an expansion member and at least one wedge member disposed between the at least one actuator and the expansion member, the wedge member having a sloped surface to slideably engage a corresponding sloped surface on the expansion member such that, in response to actuation of the at least one actuator, the at least one wedge member exerts a force on the expansion member for securing a bull gear to a crankshaft.

A pipe machining apparatus includes a frame, a tool support mounted on a tool carrier which is mounted on the frame, and a gearing arrangement for rotating the frame, and a motor for rotating the gearing arrangement. The gearing arrangement includes a toothed pinion gear, a toothed backlash adjustment gear which is moveable relative to the pinion gear and being capable of being fixed in position relative to the pinion gear by a locking assembly, and a toothed bull gear affixed to the tool carrier. The teeth of the bull gear are capable of being engaged with the teeth of the pinion gear and with the teeth of the backlash adjustment gear, the bull gear to minimize backlash.