Rock bit having cuttings channels for flow optimization

Abstract

A rock bit for blast hole drilling includes a body having a coupling formed at an upper end thereof and a plurality of lower legs, each leg having a top base, an upper shoulder, a mid shirttail, a lower bearing shaft, a leading side, a trailing side and a ported boss, and a plurality of roller cones. Each roller cone is secured to the respective bearing shaft for rotation relative thereto. A row of crushers is mounted around each roller cone. Each leading side and each trailing side are recessed relative to the respective shirttail. Each side has a cuttings channel formed therein. The rock bit further having a nozzle disposed at each ported boss. wherein each nozzle is inclined relative to a longitudinal axis of the rock bit by an outward angle.

Description

FIELD OF INVENTION[0001]The present invention relates to a rock drill bit having a body including a plurality of legs with each leg supporting a roller cone and having a ported boss formed with a nozzle for dispensing a fluid to facilitate evacuation of cuttings.BACKGROUND ART[0002]Rotary drills have emerged as an effective tool for specific drilling operations such as the creation of blast holes and geothermal wells. The drill typically comprises a rotary drill bit having three journal legs that mount respective cone-shaped rolling cutters via bearing assemblies that include rollers and balls.[0003]Typically, the drill bit is attached to one end of a drill string that is driven into the borehole via a rig. The cutting action is achieved by generating axial feed and rotational drive forces that are transmitted to the drill bit via the drill rods coupled end-to-end. Each of the cone-shaped cutters comprise externally mounted hardened cutting buttons positioned at different axial regi...

AI Technical Summary

Benefits of technology

This invention is for a rock drill bit that can quickly evacuate cuttings and minimize stress and wear on the bit. The bit has a plurality of legs that support roller cones. Each leg has a nozzle that creates a fluid jet that helps clean the cutters and hole bottom, leading to a longer operational lifetime for the bit. The nozzles are inclined, providing more efficient cleaning. Overall, this invention makes a drill bit that lasts longer and reduces the need for regrinding of cut particles.

Problems solved by technology

As will be appreciated, grinding and re-grinding of cuttings reduces the penetration rate of the bit and shortens the bit lifetime.

However, the drilling fluid jets can trap the cuttings at the bottom of the hole or at regions of the bit with the result that the cuttings are re-ground to an abrasive powder before evacuation.

Accordingly, existing drill bits are disadvantageous in that in certain instances cut material is not ejected or evacuated sufficiently from the region of cutting creating which in turn reduces cutting efficiency and leads to accelerated wear problems.

Additionally, existing drill bit legs are susceptible to stress concentrations and wear induced fatigue at specific regions that also reduces the bit operational lifetime.

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