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US 4,289,210 AGranted
Impact drill bit actuator
OwnerWilliam H. Schoefflerinventor
Life of this patent
Estimating the term…
Abstract
A rotary drive member such as a drill string, has a housing rotatably mounted at its lower end and an axial-throw cam is fixed at the lower end of the drive member in the housing. Chisel blades are axially slidable in the housing and are reciprocated by the cam in such manner that two dimetrically opposed blades are lifted and then forcibly driven downward while other chisel blades are left in contact with the well bottom to intermittently hold the housing against rotation. The chisel blades are sharpened in such a way that they tend to rotate the housing through a small angle at each downward impact.
Claims10
A well drilling assembly comprising;
- a vertically extending rotatable drive member having a cam fixed to the lower end thereof;
- a housing rotatably mounted on the lower end portion of said drive member about said cam;
- a plurality of pairs of diametrically opposed and radially extending chisel blades carried by and axially slidable on said housing and having cam follower means thereon;
- said cam being configured to sequentially lift said pairs of diametrically opposed chisel blades, one pair at a time, and then forcibly project them downwardly, upon relative rotation between said drive member and housing, while leaving the remaining chisel blades in their lower position;
- said cam comprising a cylindrical body concentric to the axis of said drive member and having upper and lower axial end faces;
- a pair of diametrically opposed camming elements on each of said axial faces.
3 more elements
Dependencies are inferred from the claim text.