Method and Apparatus for Improving Performance and Range of Conventional Power Tongs

Abstract

A jaw assembly for gripping tubular goods in a power tong. The jaw assembly has at least three (3) jaw members: a first primary jaw member, a second primary jaw member, and at least one intermediate jaw member disposed between the first and second primary jaw members. The jaw assembly can be easily and conveniently installed within a conventional 2-jaw power tong without extensive modification thereto, and increases the pipe gripping capacity of the tong (and particularly small size pipe) without damaging the pipe.

What is claimed: 
     
         1 . A gripping apparatus for gripping the external surface of a pipe with a power tong comprising:
 a) a first jaw member disposed at a first end of said gripping apparatus;   b) a second jaw member disposed at a second end of said gripping apparatus; and   c) at least one intermediate jaw member disposed between said first jaw member and said second jaw member, wherein said at least one intermediate jaw member is pivotally attached to said first jaw member and said second jaw member.   
     
     
         2 . The gripping apparatus of  claim 1 , wherein said gripping apparatus is configured to be installed in a power tong without requiring modification of said power tong. 
     
     
         3 . The gripping apparatus of  claim 1 , wherein said first jaw member and said second jaw member are engaged against said external surface of said pipe by cam surfaces of a ring gear. 
     
     
         4 . The gripping apparatus of  claim 3 , wherein said at least one intermediate jaw member is not engaged against said external surface of said pipe by a cam surface of said ring gear. 
     
     
         5 . The gripping apparatus of  claim 4 , wherein engagement of said first jaw member and said second jaw member against said outer surface of said pipe causes said at least one intermediate jaw member to contact said outer surface of said pipe. 
     
     
         6 . The gripping apparatus of  claim 1 , wherein said first jaw member, said second jaw member and said at least one intermediate jaw member are equipped with gripping dies. 
     
     
         7 . The gripping apparatus of  claim 1 , wherein said jaw members cooperate to apply radial clamping force from said power tong to said pipe. 
     
     
         8 . The gripping apparatus of  claim 7 , wherein said radial clamping force is distributed more evenly around the circumference of said pipe compared to a gripping apparatus having only two jaws. 
     
     
         9 . The gripping apparatus of  claim 1 , wherein said jaw members cooperate to apply tangential force from said power tong to said pipe. 
     
     
         10 . The gripping apparatus of  claim 9 , wherein said tangential clamping force is distributed more evenly around the circumference of said pipe compared to a gripping apparatus having only two jaws. 
     
     
         11 . A method for gripping a pipe with a power tong comprising:
 a) installing a gripping apparatus in said power tong, wherein said gripping apparatus comprises:
 i) a first jaw member disposed at a first end of said gripping apparatus; 
 ii) a second jaw member disposed at a second end of said gripping apparatus; and 
 iii) at least one intermediate jaw member disposed between said first jaw member and said second jaw member, wherein said at least one intermediate jaw member is pivotally attached to said first jaw member and said second jaw member; 
   b) engaging said first jaw member and said second jaw member against said external surface of said pipe with cam surfaces of a ring gear; and   c) engaging said at least one intermediate jaw member against said external surface of said pipe, wherein said at least one intermediate jaw member is not contacted by a cam surface of said ring gear.   
     
     
         12 . The method of  claim 11 , wherein said gripping apparatus is configured to be installed in a power tong without requiring modification of said power tong. 
     
     
         13 . The method of  claim 11 , wherein said first jaw member, said second jaw member and said at least one intermediate jaw member are equipped with gripping dies. 
     
     
         14 . The method of  claim 11 , wherein said jaw members cooperate to apply radial clamping force from said power tong to said pipe. 
     
     
         15 . The method of  claim 14 , wherein said radial clamping force is distributed more evenly around the circumference of said pipe compared to a gripping apparatus having only two jaws. 
     
     
         16 . The method of  claim 11 , wherein said jaw members cooperate to apply tangential force from said power tong to said pipe. 
     
     
         17 . The method of  claim 16 , wherein said tangential clamping force is distributed more evenly around the circumference of said pipe compared to a gripping apparatus having only two jaws.