Patent ID: 6082470
Filing Date: 2000-07-04
Classification: E21B

Abstract:
An apparatus for drilling a hole in the earth, comprising:a guide housing having a given axis,a shaft extending through said guide housing,said shaft having a central axis and a forward end,cutting means coupled to said forward end of said shaft for drilling purposes, upon rotation of said shaft,said shaft being movable longitudinally relative to said guide housing such that said shaft may be moved to a forward drilling position relative to said guide housing and to a rearward shifting position relative to said guide housing,cam means coupled to said guide housing around said shaft,a cam follower means surrounding said shaft and being rotatable relative to said shaft,said cam follower means being movable longitudinally with said shaft relative to said cam means,a clutch for coupling said cam means to said shaft to prevent rotation of said cam means relative to said shaft when said shaft is in said shifting position such that said cam means may be rotated with said shaft to allow said cam means to rotate said cam follower means to a selected angular position,when said shaft moves toward said forward drilling position, said clutch allows said cam means to be uncoupled from said shaft such that in said forward drilling position of said shaft, said cam follower means engages said cam means and causes said axis of said guide housing to shift relative to said axis of said shaft to cause the direction of drilling by said shaft and said cutting means to change,a first stop coupled to said cam follower means,a second stop coupled to said guide housing forward of said first stop such that said shaft may move said cam follower means and hence said first stop to an engaging position sufficient to engage said second stop when said shaft is moved forward,in said engaging position said cam follower means is moved forward sufficient to be uncoupled from said shaft but not far enough to significantly move said axis of said guide housing out of alignment with the axis of said shaft.