Patent ID: 7992274

Claim:
A method for making an open-head power tong comprising the steps of: providing a power tong assembly having a transmission assembly and a first case assembly including a closed-head tong assembly and a transmission shaft; providing a second case assembly comprising: an open-head tong assembly, a chain, and a pinion gear defining an opening, wherein the open-head tong assembly includes a chain sprocket and a tong head that cooperate to define an open portion in the open-head tong assembly that extends from the perimeter of the open-head tong assembly to the center region of the open-head tong assembly; a conversion shaft having a first axial end portion having a first configuration and a second axial end portion having a second configuration oppositely disposed from the first axial end portion; a casing having a sidewall, a plurality of supporting ribs, a base wall, and a top plate that cooperate to define an open side portion and an interior region that is adapted to receive the conversion shaft, the pinion gear, the open-head tong assembly, and the chain, wherein the open side portion is generally aligned with the open portion of the open-head tong assembly; wherein the conversion shaft is mounted to the casing with the first axial end portion of the conversion shaft disposed in the interior region of the casing and the second axial end portion of the conversion shaft disposed outside of the casing; wherein the opening in the pinion gear is engaged to the first axial end portion of the conversion shaft; wherein the open-head tong assembly is mounted in the interior region of the casing such that the open-head tong assembly is coupled to the pinion gear through the chain; removing the first case assembly from the transmission assembly; removing the transmission shaft from the transmission assembly to expose a transmission shaft opening; and aligning the second axial end portion of the conversion shaft with the transmission shaft opening in the transmission assembly; engaging the second axial end portion of the conversion shaft with the transmission shaft opening in the transmission assembly; and mounting the second case assembly to the transmission assembly.