Hammer drill

Abstract

A downhole apparatus connected to a workstring within a wellbore. The workstring is connected to a bit member. The apparatus includes a mandrel operatively connected to a downhole motor mechanism, an anvil member operatively formed on the bit member, the anvil member being operatively connected to the mandrel, a radial bearing housing unit operatively connected to the workstring, with the radial bearing housing unit being disposed about the mandrel, and a hammer member slidably attached to the radial bearing housing unit.

1 . An apparatus for generating an axial impact, comprising:
 a hammer segment having a radial cam surface;   an anvil segment having an internal radial shoulder, an inner wall extending from the internal radial shoulder, and one or more partial cavities adjacent to the internal radial shoulder in an internal space within the inner wall of the anvil segment;   one or more rolling elements partially disposed within the partial cavities of the anvil segment, wherein the rolling elements cooperate with the radial cam surface of the hammer segment for axially displacing the hammer segment from the anvil segment and generating the axial impact upon rotation of the hammer segment or the anvil segment, wherein each rolling element moves 360 degrees relative to the hammer segment.   
     
     
         2 . The apparatus of  claim 1 , wherein the radial cam surface of the hammer segment contacts the internal radial shoulder of the anvil segment to generate the axial impact upon rotation of the hammer segment or the anvil segment. 
     
     
         3 . The apparatus of  claim 1 , wherein the hammer segment further comprises a hammer surface and the anvil segment comprises an anvil surface. 
     
     
         4 . The apparatus of  claim 3 , wherein the hammer surface is a radial surface and the anvil surface is a radial surface. 
     
     
         5 . The apparatus of  claim 4 , wherein the hammer surface contacts the anvil surface to generate the axial impact upon rotation of the hammer segment or the anvil segment. 
     
     
         6 . The apparatus of  claim 5 , wherein the hammer surface is disposed around the radial cam surface of the hammer segment. 
     
     
         7 . The apparatus of  claim 6 , wherein the hammer surface is separated from the radial cam surface by an axial length. 
     
     
         8 . The apparatus of  claim 6 , wherein the anvil surface is disposed on an exterior surface of the anvil segment. 
     
     
         9 . The apparatus of  claim 8 , wherein the radial cam surface of the hammer segment is disposed within the inner wall of the anvil segment. 
     
     
         10 . The apparatus of  claim 2 , wherein the partial cavities are on the inner wall of the anvil segment. 
     
     
         11 . The apparatus of  claim 3 , further comprising a wear ring disposed within the internal space of the anvil segment adjacent to the internal radial shoulder, wherein the wear ring is in contact with the rolling elements. 
     
     
         12 . The apparatus of  claim 3 , further comprising a thrust race and a plurality of thrust bearings disposed within the internal space of the anvil segment, wherein the plurality of thrust bearings are disposed between the internal radial shoulder and the thrust race, and wherein the thrust race is in contact with the rolling elements. 
     
     
         13 . The apparatus of  claim 12 , wherein the thrust race rotates relative to the anvil segment as the rolling elements engage the radial cam surface of the hammer segment. 
     
     
         14 . The apparatus of  claim 13 , further comprising an internal housing disposed within the internal space of the anvil segment, said internal housing including a partial cavity dimensioned to partially house one of the rolling elements so that the rolling element is retained between the inner wall of the anvil segment and the internal housing. 
     
     
         15 . The apparatus of  claim 14 , wherein the radial cam surface of the hammer segment is disposed between the inner wall of the anvil segment and the internal housing. 
     
     
         16 . The apparatus of  claim 3 , wherein the rolling elements are not in contact with the radial cam surface when the hammer surface is in contact with the anvil surface. 
     
     
         17 . The apparatus of  claim 16 , wherein the rolling elements are equally spaced along the circumference of the radial cam surface of the hammer segment. 
     
     
         18 . The apparatus of  claim 3 , wherein the radial cam surface of the hammer segment includes a tapered portion. 
     
     
         19 . The apparatus of  claim 18 , wherein the tapered portion includes a ramp. 
     
     
         20 . The apparatus of  claim 18 , wherein the tapered portion includes an undulating waveform profile. 
     
     
         21 . An apparatus for generating an axial impact, comprising:
 an anvil segment having a radial cam surface;   a hammer segment having an internal radial shoulder, an inner wall extending from the internal radial shoulder, and one or more partial cavities adjacent to the internal radial shoulder in an internal space within the inner wall of the hammer segment;   one or more rolling elements partially disposed within the partial cavities of the hammer segment, wherein the rolling elements cooperate with the radial cam surface of the anvil segment for axially displacing the anvil segment from the hammer segment and generating the axial impact upon rotation of the hammer segment or the anvil segment, wherein each rolling element moves 360 degrees relative to the anvil segment.   
     
     
         22 - 47 . (canceled)