Replaceable blade drilling bits

Claim 2

A drill bit including: a bit body having connecting means at one end and a longitudinal flow course therethrough; said body having a substantially cylindrical enlarged lower body portion provided with a plurality of longitudinally extending recesses in its exterior surface opening from the lower end of said cylindrical portion upwardly of the body to a stop shoulder at the upper end of the recess; each of said recesses having a bottom and opposed undercut lateral portions and a locking recess at the upper end of the bottom of the recess and an inclined stop shoulder at its lower end; a detachable blade adapted to be removably mounted in each of said recesses of said bit body; each of said blades having opposed outwardly extending retaining flanges engageable in corresponding longitudinal undercut lateral portions at each side of the longitudinally extending recesses in the bit body; each of said blades having means providing a downwardly and inwardly inclined stop shoulder on th inner surface of the blade disposed to engage said stop shoulder at the lower end of the recess of the bit body substantially simultaneously with the engagement of the upper end of the body with the stop shoulder at the upper end of the recess in the bit body; and locking means carried by the blade movable into the locking recess in the bottom of the recess of the bit body to lock the blade against downward movement out of the recess on the body.

Claim 3

A drill bit of the character set forth in claim 1 wherein each of said blades has inwardly projecting stop shoulders at its lower inner end engageable with complementary stop shoulders on adjacent blades to provide support against inward lateral displacement of the blades during use.

Claim 4

A drill bit including: a bit body having connecting means at one end and an enlarged substantially cylindrical body portion at its opposite end extending longitudinally from said connecting means and having a longitudinal flow passage therethrough; a plurality of longitudinally extending blaDe receiving recess on the exterior surface of the enlarged cylindrical body portion extending from the opposite end thereof toward the connecting means; each blade receiving recess having a bottom and a laterally outwardly undercut retaining shoulder along each longitudinal side thereof; a first outwardly directed stop shoulder at the end of the recess nearest the connecting means and a second stop shoulder at the opposite end of said recess extending angularly toward the end of the cylindrical body portion opposite the connecting means and inwardly toward the longitudinal axis of the body; each of said blade receiving recesses having a locking recess in its bottom adjacent and spaced from the end of the recess nearest the connecting means on the body; a plurality of interchangeable substantially identical replaceable cutter blades on of each adapted to be removably mounted in one of each of the recesses of said bit body and secured therein independently of the other blades in the other recesses; each of said blades lateral retaining flanges of a shape fitting beneath the undercut shoulders along the sides of the blade receiving recesses and having longitudinally spaced stop shoulders engageable with the first and second stop shoulders on the body to limit movement of the blades in the recesses toward the connecting means of the body; releasable securing means on each blade adjacent and spaced from the end thereof nearest the outwardly directed shoulder at the end of the recess nearest theconnecting means on the body and movable into the locking recess in he bottom of the blade receiving recess to secure the blade in said recess with the stop shoulders on the blade engaged with the stop shoulders on the body, whereby said blades are each interchangeable with the blades in the other recesses, so that any one blade will fit in and be lockable in each of the recesses of the bit body; said securing means on said blades being retractable from the locking recesses in the body to permit said blades to be each separately removable from and replaceable in the blade receiving recess of thebit body in which it is disposed without disturbing the other blades in the other blade receiving recesses.

Claim 5

A drill bit including: a bit body having connecting means at one end and an enlarged substantially cylindrical body portion at its opposite end extending longitudinally from said connecting means and having a longitudinal flow passage therethrough; a plurality of longitudinally extending blaDe receiving recess on the exterior surface of the enlarged cylindrical body portion extending from the opposite end thereof toward the connecting means; each blade receiving recess having a bottom and a laterally outwardly undercut retaining shoulder along each longitudinal side thereof; a first outwardly directed stop shoulder at the end of the recess nearest the connecting means and a second stop shoulder at the opposite end of said recess extending angularly toward the end of the cylindrical body portion opposite the connecting means and inwardly toward the longitudinal axis of the body; each of said blade receiving recesses having a locking recess in its bottom adjacent and spaced from the end of the recess nearest the connecting means on the body; a plurality of interchangeable substantially identical replaceable cutter blades on of each adapted to be removably mounted in one of each of the recesses of said bit body and secured therein independently of the other blades in the other recesses; each of said blades lateral retaining flanges of a shape fitting beneath the undercut shoulders along the sides of the blade receiving recesses and having longitudinally spaced stop shoulders engageable with the first and second stop shoulders on the body to limit movement of the blades in the recesses toward the connecting means of the body; releasable securing means on each blade adjacent and spaced from the end thereof nearest the outwardly directed shoulder at the end of the recess nearest theconnecting means on the body and movable into the locking recess in he bottom of the blade receiving recess to secure the blade in said recess with the stop shoulders on the blade engaged with the stop shoulders on the body, whereby said blades are each interchangeable with the blades in the other recesses, so that any one blade will fit in and be lockable in each of the recesses of the bit body; said securing means on said blades being retractable from the locking recesses in the body to permit said blades to be each separately removable from and replaceable in the blade receiving recess of thebit body in which it is disposed without disturbing the other blades in the other blade receiving recesses.

Claim 6

A drill bit of the character set forth in claim 3 wherein the releasable securing means comprises a lock bolt threaded through the blade at an angle with respect to the bottom of the groove and directed angularly inwardly toward the longitudinal axis of the body and divergent from said first stop shoulder on said body.

Claim 7

A drill bit of the character set forth in claim 3 wherein each of said blades has inwardly projecting stop shoulders at its lower inner end engageable with complementary stop shoulders on adjacent blades to support the lower cutting edge portion of the blades against inward lateral displacement of the bit body during use.