Rock drilling tool and reamer for percussive drilling
AssigneeSandvik AB
InventorsDaniel Lindgren, Per-Olof Liljebrand, Håkan Lindström
Life of this patent
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Abstract
A rock drilling tool includes a pilot bit screw threaded into a front end of a drill rod. A reamer is mounted on the outside of the pilot bit. The reamer includes a central opening having a front portion and a rear portion. The front portion is connected to the pilot bit, and the rear portion constitutes a stiffening sleeve which extends around the outside of the drill rod.
Claims13
A percussive rock drilling tool comprising a drill rod, a pilot bit, and a reamer;
- the drill rod including a front portion having a first screw thread;
- the pilot bit having a second screw thread threadedly mounted to the first screw thread to form therewith a screw thread connection, the pilot bit projecting longitudinally forwardly beyond the drill rod;
- the reamer surrounding the pilot bit and including a front portion carrying rock cutting structure, the reamer including an opening through which the pilot bit projects and a rearwardly extending stiffening sleeve integral with the front portion, the stiffening sleeve extending along an outer surface of the drill rod for a portion of the screw thread connection.
A reamer adapted for use on a percussive rock drilling tool, comprising a body having a front end carrying a rock cutting structure, the body including a central opening having a front portion for engaging a pilot bit, and a rear stiffening portion for engaging a drill rod, a smallest diameter of the central opening in the rear portion being larger than a smallest diameter of the front portion of the central opening, wherein the front portion of the central opening has an internal screw thread, and the rear portion is circular cylindrical.
A reamer adapted for use on a percussive rock drilling tool, comprising a body having a front end carrying a rock cutting structure, the body including a central opening having a front portion for engaging a pilot bit, and a rear stiffening portion for engaging a drill rod, the front portion of the central opening being conical and tapering in a forward direction, and the rear portion being circular cylindrical, a smallest diameter of the cylindrical rear portion being larger than a smallest diameter of the conical front portion.
Dependencies are inferred from the claim text.