Abstract: A power tong unit having a gear train in which one or more of the gears in the gear train have removable and replacement roller tooth elements, in lieu of conventional gear teeth. In one embodiment, the ring gear and pinion gears have roller tooth elements, and idler gears disposed between the ring gear and pinion gears, have a semi-circular tooth root profile to mesh with the roller element gear teeth. The ring gear of the power tong unit may also have a removable section. A means for removing the removable section from the ring gear, and moving it to a position in which a tubular can be inserted into a central opening in the ring gear, may include a hydraulic cylinder, a clamping mechanism, and a cam surface to generate rotation of the removable section once lifted out of engagement with the ring gear.

Abstract: A power tong unit having a gear train in which one or more of the gears in the gear train have removable and replacement roller tooth elements, in lieu of conventional gear teeth. In one embodiment, the ring gear and pinion gears have roller tooth elements, and idler gears disposed between the ring gear and pinion gears, have a semi-circular tooth root profile to mesh with the roller element gear teeth. The ring gear of the power tong unit may also have a removable section. A means for removing the removable section from the ring gear, and moving it to a position in which a tubular can be inserted into a central opening in the ring gear, may include a hydraulic cylinder, a clamping mechanism, and a cam surface to generate rotation of the removable section once lifted out of engagement with the ring gear.

Abstract: A tong unit having a ring gear, an upper cage plate, and a jaw assembly is disclosed. The cage plate has a removable window section, through which the jaw assembly may be inserted into and removed from the central opening in the ring gear. The jaw assembly may be attached to the removable window section, so that the window section and the jaw assembly can be lifted out and inserted together.

Abstract: A power tong having a ring gear and dumbell rollers, with mating load surfaces on the ring gear and dumbell rollers which transfer horizontal and vertical loads from the ring gear to the dumbell rollers, without contact between the ring gear teeth and the dumbell rollers. The power tong further has a dumbell roller shaft configuration which permits vertical and rotational locking of the shaft, while permitting easy replacement and without binding of the rotation of the top and bottom plates on the dumbell rollers.