Drill bit with yielding support and force applying structure for abrasion cutting elements

A rotary drill bit for drilling a well bore in an earth formation, which includes a body structure, and at least one cutter wheel rotationally connected to the body structure at a fixed operative position, and a plurality of compression cutting elements connected to the cutter wheel and rotatable into contact with the earth formation in primarily an indentor mode of cutting attack, and at least one abrasion cutting element operatively retained for contact with the earth formation in a drag mode of cutting contact, and an improvement in combination therewith, comprising:

• means connecting the abrasion cutting element to the body structure for operative reciprocative movement between a retracted position and an extended position, the extended position operatively locating the abrasion cutting element downwardly and radially outwardly with respect to the retracted position to assist the indentor cutting elements in advancing the well bore at a drill face of the well bore.

A rotary drill bit for drilling a well bore in an earth formation, which includes a body structure, and at least one cutter wheel rotationally connected to the body structure at a fixed operative position, and a plurality of compression cutting elements connected to the cutter wheel and rotatable into contact with the earth formation in primarily an indentor mode of cutting attack, and at least one abrasion cutting element operatively retained for contact with the earth formation in a drag mode of cutting contact, and an improvement in combination therewith, comprising:

• means connecting the abrasion cutting element to the body structure for operative reciprocative movement between an extended position and a retracted position, and wherein in its extended position the abrasion cutting element operatively cuts a circular recessed groove into the earth formation at a drill face of the well bore which is circumjacent a side wall of the well bore, and the groove extends to an axial depth greater than the depth of the remaining earth formation at the drill face spaced radially inward from the groove.

A rotary drill bit for drilling a well bore in an earth formation, which includes a body structure, and at least one cutter wheel rotationally connected to the body structure at a fixed operative position, and a plurality of compression cutting elements connected to the cutter wheel and rotatable into contact with the earth formation in primarily an indentor mode of cutting attack, and at least one abrasion cutting element operatively retained for contact with the earth formation in a drag mode of cutting contact, and an improvement in combination therewith, comprising:

• means connecting the abrasion cutting element to the body structure for operative reciprocative movement between an extended position wherein the abrasion cutting element is operative to assist the indentor cutting elements in advancing the well bore at a drill face of the well bore and a retracted position which is radially inwardly spaced from the extended position, said means connecting the abrasion cutting element for operative reciprocative movement operatively positions the abrasion cutting element in its extended position for cutting a recessed groove at the outer circumference of the drill face which extends to an axial depth greater than the depth of the remaining earth formation at the drill face spaced radially inward from the groove.