An expandable drilling apparatus is deployed upon a distal end of a drillstring, and includes a cutting head and a substantially tubular main body adjacent the cutting head providing a plurality of axial recesses configured to receive arm assemblies configured to translate between a retracted and an extended position. A flow switch actuates the arm assemblies when a drilling fluid pressure exceeds an activation value and the drilling apparatus includes a biasing member to reset the arm assemblies when the drilling fluid pressure falls below a reset value.
申请公布号
CA2723505(C)
申请公布日期
2014.02.25
申请号
CA20072723505
申请日期
2007.01.15
申请人
SMITH INTERNATIONAL, INC.
发明人
CAMPBELL, JOHN E.;DEWEY, CHARLES H.;UNDERWOOD, LANCE D.;SCHMIDT, RONALD G.