Pipe gripping ram

Abstract

A ram is provided for use in the live and dead heads of an iron roughneck. The ram grips sections of pipe as connections are made or broken between the pipe sections. The ram includes a cylinder block having a bore and a fixed piston centered therein forming an annulus. An annular piston slides in and out of the cylinder block in the annulus. A tong mounted on the end of the end of the annular piston for gripping pipe includes a tong shoe and a tong die within the shoe. The tong die is capable of moving side-to-side within the shoe to self-center itself when gripping pipe. Pressurized gas or hydraulic fluid systems can be used to extend and retract the annular piston within the cylinder block.

1 . A pipe gripping ram, comprising: 
 a) a cylinder block having first and second ends and a bore extending therebetween along a longitudinal axis, said bore forming an interior cylinder wall within said cylinder block;    b) an end cap operatively attached to the first end of said cylinder block thereby enclosing said bore at said first end;    c) a fixed piston having a head and a neck disposed within said bore, said head larger in diameter than said neck, said neck operatively attached to said end cap whereby said fixed piston head is longitudinally aligned with said longitudinal axis and thereby forming a substantially uniform annulus between said fixed piston head and said interior cylinder wall, said annulus extending from the second end of said cylinder block at least partially along said bore towards said end cap;    d) an annular piston having first and second ends, the first end of said annular piston being open and adapted to slidably couple with said fixed piston whereby said annular piston is capable of linear reciprocal motion along said annulus, the second end of said annular piston being closed and forming a first chamber when said annular piston is slidably coupled with said fixed piston, the first end of said annular piston further comprising a stop to prevent said annular piston from sliding off said fixed piston, the combination of said fixed piston and the first end of said annular piston forming a second annular chamber;    e) a pipe gripping tong operatively attached to the second end of said annular piston; and    f) means for moving said annular piston in a linear reciprocal motion within said annular bore.    
   
   
       2 . The ram as set forth in  claim 1  wherein said bore is substantially cylindrical.  
   
   
       3 . The ram as set forth in  claim 1  wherein said means for moving said annular piston comprises a hydraulic fluid system.  
   
   
       4 . The ram as set forth in  claim 1  wherein said means for moving said annular piston comprises a pneumatic air system.  
   
   
       5 . The ram as set forth in  claim 3  further comprising a first passageway disposed within said fixed piston providing communication to said first chamber for hydraulic fluid to enter said first chamber and move the second end of said annular piston away from said cylinder block.  
   
   
       6 . The ram as set forth in  claim 5  further comprising a second passageway disposed within said fixed piston providing communication to said second annular chamber for hydraulic fluid to enter said second annular chamber and move the second end of said annular piston towards said cylinder block.  
   
   
       7 . The ram as set forth in  claim 4  further comprising a first passageway disposed within said fixed piston providing communication to said first chamber for pressurized gas to enter said first chamber and move the second end of said annular piston away from said cylinder block.  
   
   
       8 . The ram as set forth in  claim 7  further comprising a second passageway disposed within said fixed piston providing communication to said second annular chamber for pressurized gas to enter said second annular chamber and move the second end of said annular piston towards said cylinder block.  
   
   
       9 . The ram as set forth in  claim 1  wherein said tong further comprises a tong shoe and tong die for gripping a pipe disposed within said tong shoe, said tong die capable of lateral movement within said tong shoe.  
   
   
       10 . The ram as set forth in  claim 6  further comprising a swash plate mechanism for controlling the direction of hydraulic fluid into and out of said first and second passageways.  
   
   
       11 . The ram as set forth in  claim 8  further comprising a swash plate mechanism for controlling the direction of pressurized air or gas into or out of said first and second passageways.