Supported shear with reversible drive and method of operating same

Abstract

A reversible linear hydraulic drive system for a bidirectional supported shear having an adjustable stroke length. A method for improving the quality of the tube ends after shearing using a reversible partial orbital path is also disclosed.

What is claimed is:  
     
         1 . In a supported shear of the type in which axially adjacent and integral lengths of linear stock such as tubing are laterally displaced relative to one another along a shear plane at right angles to the longitudinal axis of said stock: 
 non-driven ram means for receiving and holding said stock;    driven ram means adjacent the non-driven ram means for receiving said stock; and    means for alternately driving said moveable ram in opposite directions through an orbital path relative to the non-driven ram.    
     
     
         2 . Apparatus as defined in  claim 1  wherein the means for driving includes first and second hydraulic cylinders.  
     
     
         3 . Apparatus as defined in  claim 1  wherein said means for driving comprises: 
 a pinion connected to said driven ram;  
 a first rack engaged with the pinion and mounted for linear translation to rotate said pinion in a first direction; and  
 a second rack engaged with the pinion and mounted for linear translation to rotate said pinion in a second direction.  
 
     
     
         4 . Apparatus as defined in  claim 3  further comprising: 
 power means for causing linear translation of said first and second racks in opposite directions.  
 
     
     
         5 . Apparatus as defined in  claim 4  further including means for varying the power level of said power means during translation of said rack.  
     
     
         6 . Apparatus as defined in  claim 3  wherein the total linear displacement of said first rack is at least approximately equal to one revolution of said drive shaft.  
     
     
         7 . Apparatus as defined in  claim 1  wherein: 
 said stock is tubular; and  
 said shear further comprises a mandrel extensible into said stock in the location of the shear plane to maintain the shape thereof during a shearing operation.  
 
     
     
         8 . For use in combination with a bladeless shear for linear stock which shear comprises a stock-receiving ram having an eccentrically driven wheel disposed therein, a wheel drive comprising: 
 a drive shaft connected to said wheel;    a pinion connected to said shaft for rotation therewith;    first and second racks engaging said pinion and linearly translatable to rotate the pinion in respective first and second opposite directions; and    power means for translating said racks.    
     
     
         9 . In a bladeless shear device of the type having first and second tools aligned with a work piece axis and means for causing orbital motion of one of the tools relative to the other: 
 an actuator having a linearly translating drive component; and    means for converting the linear translation of the drive component into orbital motion of said one tool.