Reaming tool with radially extending blades

Abstract

A downhole reaming tool is disclosed having radially extendible cutting blades extended by hydraulic pressure directed into the tool to force an inner tubular body having protrusions thereon with tapered sides forward against the walls of mating recesses defined in such radially extendible cutting blades to extend the blades.

I claim:  
     
         1 . A reaming tool having a longitudinal axis, said tool comprising: 
 an inner tubular body;    at least one protrusion disposed on said inner tubular body, said protrusion having tapered sides and a shape;    at least one radially extendible cutting blade, said cutting blade having at least one recess defined therein for receipt of said protrusion, said recess having tapered walls and shape mating with the shape of said protrusion;    means to move said inner tubular body forward; and    means to retain said radially extendible cutting blade from moving forward while allowing said cutting blade to move radially outward forced by contact of said tapered protrusion against a side of said recess defined in said radially extendible cutting blade.    
     
     
         2 . The reaming tool of  claim 1  further including: 
 a plurality of cutting blades radially disposed around said inner tubular body.  
 
     
     
         3 . The reaming tool of  claim 2  further including: 
 at least two protrusions disposed on said inner tubular body, each having a tapered side; and  
 at least two recesses defined in said cutting blades for receipt of said protrusions in mating relationship therewith.  
 
     
     
         4 . The reaming tool of  claim 2  further including: 
 a plurality of protrusions disposed on said inner tubular body, each having a tapered side; and  
 a plurality of mating recesses defined in said cutting blades for receipt of said protrusions in mating relationship therewith.  
 
     
     
         5 . The reaming tool of  claim 4  wherein said means to move said inner tubular body comprises a mandrel adapted for receipt of hydraulic pressure thereon, said mandrel engaged against said inner tubular body, said reaming tool further including a spring for returning said mandrel to an inactive position once said hydraulic pressure has been reduced below the compression level of said spring.  
     
     
         6 . The reaming tool of  claim 5  wherein each protrusion on said inner tubular body is of a shape selected from the group consisting of curved, pyramidically tapered and conically tapered shapes and wherein the angle of tapering of the sides of the protrusion is between 20 degrees and 60 degrees.