Jaws for power tongs and back-up units
OwnerDamon T. Slatorinventor
Life of this patent
Estimating the term…
Abstract
An improvement is made to jaw designs for power tongs and back-up units. The jaw is formed having a cavity whose opening is oriented toward the pipe to be gripped. An elongated die is movably mounted in the cavity effectively closing off the cavity. The die has a gripping surface adapted to contact the pipe. A resilient member, preferably synthetic rubber or other elastomer or a substantially incompressible fluid, is disposed within the cavity adjacent the die. Uneven loads on the die are redistributed through the hydraulic action of the resilient member with a resultant equal distribution of the loads on the die.
Claims11
In a power tong or back-up unit having a plurality of jaws, each jaw having a roller mounted thereon adapted to engage a camming surface, each jaw guided by guideways in a spider, whereupon relative movement between the camming surface and the spider results in radial movement of said jaws toward a pipe, the improvement in each jaw comprising:
- said jaw having a cavity whose opening is oriented toward the pipe to be gripped;
- a pipe-gripping die movably mounted in said cavity effectively closing off said cavity, said die having a gripping surface adapted to contact the pipe;
- an elastomer means disposed within and filling said cavity behind said die for providing a substantially even distribution of forces, equivalent to force distribution in a confined hydraulic medium, along the entire length of said die upon an uneven force being applied on said die when there is contact between said die and the pipe;
- whereupon the pressure applied by said die on the pipe is resultantly substantially uniform over the said gripping surface of said die.
An improved guided jaw for power tongs or back-up unit used to connect and disconnect adjacent lengths of pipe, said jaw comprising:
- a cavity whose opening is oriented toward the pipe to be gripped;
- a pipe engaging die movably mounted in said cavity effectively closing off said cavity said die having a gripping surface adapted to contact the pipe;
- an elastomer means disposed within and filling said cavity behind said die for providing a substantially even distribution of forces, equivalent to force distribution in a confined hydraulic medium, along the entire length of said die upon an uneven force being applied on said die when there is contact between said die and the pipe;
- and
- whereupon the pressure applied by said die on the pipe is resultantly substantially uniform over the said gripping surface of said die.
Dependencies are inferred from the claim text.