公开(公告)号：EP2191094A1

公开(公告)日：2010-06-02

申请号：EP08782977.6

申请日：2008-08-21

申请人： Gilbert, Andrew Stephen ,  Thompson, Barry John

发明人： Gilbert, Andrew Stephen ,  Thompson, Barry John

IPC分类号： E21B4/14 ,  E21B6/00 ,  E21B4/06 ,  E21B10/36

CPC分类号： E21B10/36 ,  E21B4/06 ,  E21B17/076

摘要： A down-hole hammer comprising a drill bit (10) and a drive sub (11) with an interconnection therebetween for causing rotation of the drill bit upon rotation of the drill sub. The drill bit (10) comprises a drill bit head (13) and a shank (19), the drill bit head (13) defining a cutting face (15) and having a circumferential shoulder section (17) adjacent the cutting face (15). The shank (19) extends from the shoulder section (17) in the direction away from the cutting face (15). The interconnection between the drill bit (10) and the drive sub (11) comprises a spline assembly including at least one spline (43) on the shoulder section (17) for mating engagement with at least one counterpart spline (63) on the drive sub (11) to provide a drive coupling therebetween while also allowing the drill bit (10) to slide axially within the drive sub (11) to perform a percussive action.