Replaceable tong die inserts for pipe tongs

Abstract

A gripping assembly for pipe tongs is provided to grip and rotate a pipe. The gripping assembly includes a pair of jaw assemblies that exert counteracting forces on the pipe. Each jaw assembly has a body with a cylindrical hollow defined in the body and having longitudinal slots formed in the body. The slots are separated from one another by longitudinal struts. In a cross section perpendicular to the longitudinal direction of the cylindrical hollow, flat faces of the slots form portions of a regular polygon. Each jaw assembly also has toothed tong die inserts that fit into the slots and provide for frictional engagement of the jaw assembly with the pipe. Each jaw assembly also has a first and a second end plate for retaining the tong dies in the slots with at least one of the end plates being removably attached to the body.

What is claimed is:  
     
         1 . A jaw assembly for pipe tongs with a rotation assembly housing, the pipe tongs being a device for rotating a pipe, comprising: 
 (a) a body having a cylindrical hollow defined therein and having longitudinal slots formed therein;    (b) tong die inserts fitting into the slots for providing frictional engagement of the jaw assembly with the pipe;    (c) first and second end plates normal to the longitudinal direction to retain the tong dies inserts in the slots; and    (d) a base attached to the body and to the housing.    
     
     
         2 . The jaw assembly of  claim 1  wherein the slots are separated from one another by struts that extend in a longitudinal direction of the cylindrical hollow.  
     
     
         3 . The jaw assembly of  claim 1  wherein, in a cross section normal to the longitudinal direction of the cylindrical hollow, flat faces of the slots form portions of a regular polygon.  
     
     
         4 . The jaw assembly of  claim 1  wherein each of the slots have a partial trapezoidal shape in a cross section normal to the longitudinal direction of the cylindrical hollow.  
     
     
         5 . The jaw assembly of  claim 1  wherein the first end plate is removably attached to the body.  
     
     
         6 . The jaw assembly of  claim 1  wherein the second end plate is removably attached to the body.  
     
     
         7 . The jaw assembly of  claim 1  wherein the second end plate is welded to the body.  
     
     
         8 . The jaw assembly of  claim 1  wherein the second end plate is integrally formed with the body.  
     
     
         9 . The jaw assembly of  claim 1  wherein the tong die inserts are substantially identical.  
     
     
         10 . The jaw assembly of  claim 1  wherein top faces of each tong die insert are arcuate.  
     
     
         11 . The jaw assembly of  claim 10  wherein, when the tong die inserts are positioned in the slots, the top faces of the tong die inserts substantially define an arc of a circle.  
     
     
         12 . The jaw assembly of  claim 11  wherein a radius of the circle defined by the top faces of the tong die inserts is substantially the same as a radius of the pipe.  
     
     
         13 . The jaw assembly of  claim 12  wherein a bottom of each tong die insert is flat.  
     
     
         14 . The jaw assembly of  claim 1  wherein there are at least three slots.  
     
     
         15 . A gripping assembly for pipe tongs that grip and rotate a pipe, the gripping assembly comprising jaw assemblies for exerting counteracting forces on the pipe, wherein each jaw assembly comprises: 
 (a) a body having a cylindrical hollow defined therein and having longitudinal slots formed therein;    (b) tong die inserts fitting into the slots for providing frictional engagement of the jaw assembly with the pipe;    (c) first and second end plates normal to the longitudinal direction to retain the tong die inserts in the slots; and    (d) a base attached to the body and to the housing.    
     
     
         16 . The gripping assembly of  claim 15  having two jaw assemblies that exert opposed, counteracting forces on the pipe.  
     
     
         17 . The gripping assembly of  claim 16  further comprising a ram corresponding to each jaw assembly to apply an inward force to each corresponding jaw assembly.  
     
     
         18 . The gripping assembly of  claim 15  wherein at least one of the first end plate and the second end plate of each jaw assembly is removably attached to the body.  
     
     
         19 . The gripping assembly of  claim 15  wherein top faces of each tong die insert are arcuate.  
     
     
         20 . The gripping assembly of  claim 19  wherein, when the tong die inserts are positioned in the slots, the top faces of the tong die inserts for each jaw assembly substantially define an arc of a circle.  
     
     
         21 . The gripping assembly of  claim 20  wherein, for each jaw assembly, a radius of the circle defined by the top faces of the tong die inserts is substantially the same as a radius of the pipe.  
     
     
         22 . The gripping assembly of  claim 21  wherein a bottom of each tong die insert is flat.  
     
     
         23 . The gripping assembly of  claim 16  wherein the tong die inserts are in contact with two-thirds of a circumference of the pipe.  
     
     
         24 . A tong die insert for a gripping assembly for gripping a pipe, comprising: 
 (a) a flat bottom surface; and    (b) an arcuate top surface with a radius of curvature substantially equal to a radius of the pipe.