Inclined leg earth-boring bit

An earth-boring bit has a body 13 with a threaded pin 15 on the upper end for connecting to a drill string. Bit legs 17 are formed symmetrically on the exterior of the body and extend downward. The lower portion 17b of each bit leg is inclined and offset circumferentially from the upper portion 17a....

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: KEVIN W SCHADER, GREGORY L RICKS, GLENN R ZADRAPA, ROBERT E GRIMES, KENNETH C BRANNON
Format: Patent
Sprache:eng
Schlagworte:
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Beschreibung
Zusammenfassung:An earth-boring bit has a body 13 with a threaded pin 15 on the upper end for connecting to a drill string. Bit legs 17 are formed symmetrically on the exterior of the body and extend downward. The lower portion 17b of each bit leg is inclined and offset circumferentially from the upper portion 17a. A cutter 29 is mounted to the lower portion of each bit leg for rotation about a cutter axis. Nozzle bosses 47 are located between each bit leg. A flow channel 55,57 exists on both sides of each nozzle boss. The nozzle boss is inclined in a similar direction to the bit leg. The upper portion 17a of each leg is preferably parallel to the bit axis and has a point of contact 45 with the bore. This point of contact is approximately diametrically opposed to the point of contact 43 of a cutter. This gives the bit six circumferentially spaced contact points to enhance bit stability.