Hydraulic pipe tong apparatus

Claim 1

Pipe tong apparatus comprising a horizontal support frame providing a central opening adapted to receive a vertically disposed length of pipe; pipe gripping means carried by said support frame, said pipe gripping means including a plurality of horizontally and radially disposed pipe gripping units arcuately arranged about said central opening, each of said pipe gripping units having a cylinder guide carried by said support frame and providing a radially extending guideway therein, said guideway being rectangular in cross-section normal to its radial dimension, a blind cylinder disposed in said guideway and having a rectangular cross-section complemental to the cross-section of said guideway for preventing rotation of said cylinder within said guideway, the blind end of said cylinder facing said central opening, pipe engaging jaw means mounted on said blind end, said cylinder being slidable in said guideway to move said jaw means into and out of engagement with a length of pipe in said opening, a piston fitted within said cylinder, a piston rod having one end fixed to said piston and the other end fixed to said frame, said piston and said cylinder defining a fluid pressure chamber at said blind end of said cylinder, fluid pressure manifOld means for simultaneously introducing fluid under pressure into the fluid pressure chambers of all of said pipe gripping units to slide their respective cylinders towards a pipe disposed in said central opening, thereby to move their respective jaw means into gripping engagement with the pipe, and retraction means associated with each of said units for sliding their respective cylinders away from the pipe, thereby to move their respective jaw means out of engagement with the pipe.