No Vibration Stone Column Drill

Abstract

A drill including a drill flight where the drill flight changes angle from a primary flight angle (A 1 ) to a secondary flight angle (A 2 ).

1 . A stone column drill including a drill flight wherein the drill is a tubular drill including a drill body which is a tube, such that the drill flight is attached to a body outer surface of the drill body, where the body outer surface is the exposed outer surface of the drill body characterized in that the drill flight changes angle from a primary flight angle (A 1 ) to a secondary flight angle (A 2 ) at a transition distance (TD) from a around terminal end of the drill, where the ground terminal end of the drill is the end of the drill that is configured to enter the ground first. 
     
     
         2 - 3 . (canceled) 
     
     
         4 . The drill as claimed in  claim 1  wherein, the transition distance (TD) is 0.1 m to 0.75 m. 
     
     
         5 . The drill as claimed in  claim 1  wherein, the transition distance is 0.2 m to 0.6 m. 
     
     
         6 . The drill as claimed in  claim 1  wherein:
     A 1=5° to 35°;
 
     A 2=30° to 70°; and
 
     A 2≥ A 1+5°.
 
 
     
     
         7 . The drill as claimed in  claim 6  wherein, A 2 ≥A 1 +10°. 
     
     
         8 . The drill as claimed in  claim 6  wherein, A 2 ≥A 1 +15°. 
     
     
         9 . The drill as claimed in  claim 6  wherein, A 2 ≥A 1 +20°. 
     
     
         10 . The drill as claimed in  claim 1  wherein, the transition from A 1  to A 2  is a sharp transition. 
     
     
         11 . The drill as claimed in  claim 1  wherein, the transition from A 1  to A 2  occurs over a transition zone, where the transition zone extends circumferentially around the drill. 
     
     
         12 . The drill as claimed in  claim 1  wherein, the drill is a multi-start drill with one or more additional flights. 
     
     
         13 . The drill as claimed in  claim 12  wherein, the drill is a two start drill and the additional flight makes ⅓ to 2 turns about the drill before terminating. 
     
     
         14 . The drill as claimed in  claim 12  wherein, the or each additional flight terminates at or just prior to the transition distance. 
     
     
         15 . The drill as claimed in  claim 1 , the drill body further includes one or more compactors, where each compactor present extends radially from the drill body. 
     
     
         16 . The drill as claimed in  claim 15  wherein, each compactor present is a minimum of 1 m to 3 m from the ground terminal end of the drill. 
     
     
         17 . The drill as claimed in  claim 15  wherein, each compactor extends, at least partially, between two facing portions of the drill flight. 
     
     
         18 . The drill as claimed in  claim 17  wherein, the facing portions are circumferentially separated by between 270° and 360°. 
     
     
         19 . The drill as claimed in  claim 15  wherein, one or more compactor is longitudinally aligned with the drill. 
     
     
         20 . The drill as claimed in  claim 15  wherein, the distance each compactor present extends radially from the drill body is between 0.1 and 1.2 times the flight height (FH), where the flight height (FH) is the distance between a peripheral edge of the drill flight and the drill body. 
     
     
         21 . The drill as claimed in  claim 15  wherein, the drill flight has a pitch P, and each compactor present independently extends 0.1P to 1P along the length of the drill. 
     
     
         22 . The drill as claimed in  claim 15  wherein, each compactor present is, independently, at an angle of 0° to 90° to the longitudinal axis of the drill. 
     
     
         23 . The drill as claimed in  claim 15  wherein, at least one compactor present is attached to the drill flight at one end. 
     
     
         24 . The drill as claimed in  claim 1  wherein, each drill flight terminates at a terminal end which includes a keeper configured to retain an asymmetric drill tooth. 
     
     
         25 . The drill as claimed in  claim 24  wherein, the asymmetric drill tooth includes a first face that is configured to lie on a plane that is at an angle LA from 30° to 70° to the longitudinal axis of the drill in a first configuration, and on a plane that is at an angle LA from 30° to −30° to the longitudinal axis of the drill in a second configuration. 
     
     
         26 . The drill as claimed in  claim 1  wherein, the drill includes an epicyclic gearbox which further includes a sun gear unit, where the sun gear unit includes a sun gear, an engagement unit and an engagement bias unit, where the engagement bias unit lies between the sun gear and the engagement unit, said engagement bias unit is configured to apply a bias force between the sun gear and the engagement unit, wherein the engagement unit includes a longitudinally co-axial open ended engagement tunnel which is configured to releasably engage with a shaft or tube rotationally locking the sun gear to that shaft or tube. 
     
     
         27 . The drill as claimed in  claim 26  wherein, the engagement bias unit is selected from a flat spring, a coil spring, a pressurised gas filled bag/ring, two or more like pole opposed magnets, an elastomeric material, a combination of two or more elastomeric materials or a combination of two or more of these. 
     
     
         28 . The drill as claimed in  claim 26  wherein, the shaft or tube includes at least one drive units and the engagement unit includes one or more engagement channels, where each engagement channel is dimensioned to accept one of the at least one drive units. 
     
     
         29 . The drill as claimed in  claim 28  wherein, the cross-sectional shape of the one or more engagement channels is rectangular. 
     
     
         30 . The drill as claimed in  28  wherein, each engagement channel parallel to the engagement tunnel. 
     
     
         31 . The drill as claimed in  28  wherein, each engagement channel forms a helical path along the length of an inside wall of the engagement tunnel.