Sandvik Ab

Goran Palmberg

Jan-Gunnar Hedlund

Hangkan Engstrom

A rock drill for percussive drilling includes a shank, a collar connected to a front end of the shank, and a rod portion which at one end connects to the collar while the other end carries a rock cutting means. A central flush channel extends from the front free end of the shank in a direction towards the front end. The central flush channel has a substantially constant diameter (d) along essentially its entire length; a ratio of the diameter (d) to a smallest outer cross sectional width (D) of the rod portion being in the range of 0.35 to 0.43.

Rock drill having an internal flushing channel

A rock drill bit for percussive drilling includes a head and a shank. The shank has a central boring in which a thread is provided. The thread cooperates with a corresponding thread in a drill string driven by a top hammer. The boring is connected to at least one fluid passage which emerges in or in the vicinity of a front face of the head. The fluid passage connects to a first groove which connects to a second groove, wherein at least three second grooves are provided and form between them axially forward lands. Each land carries a gauge insert. The gauge inserts are asymmetrically positioned on the drill bit, and the second groove extends radially inwards to or beyond an imaginary circle touching the radially innermost points of the inserts.

Growing community of inventors

Radovia Raposo Tavares, Brazil

Goran Palmberg