Cutting bit useful for impingement of earth strata

Abstract

A cutting bit for impinging earth strata wherein the cutting bit includes a highly wear-resistant elongate cutting bit body, which has an axial forward end and an axial rearward end, an enlarged dimension head portion at the axial forward end and a reduced dimension shank portion at the axial rearward end. The highly wear-resistant elongate cutting bit body has a maximum transverse dimension and a longitudinal axial length. The cutting bit includes a superhard insert, which is affixed to the head portion at the axial forward end of the cutting bit body. The cutting bit has a slimness ratio, which comprises the ratio of the maximum transverse dimension to the longitudinal axial length wherein the cutting bit exhibits a slimness ratio ranging between about 0.15 and about 0.60.

Description

BACKGROUND OF THE INVENTION[0001]The present invention pertains to a cutting bit for impingement of earth strata. More specifically, the present invention pertains to a cutting bit for impingement of earth strata wherein the cutting bit, which exhibits excellent wear resistance and impact resistance, encounters less resistance and exhibits better rotational properties and longer useful tool life than prior cutting bits.[0002]Heretofore, cutting bits (e.g., rotatable cutting bits) used for mining, trenching and construction applications including a road planing applications comprise an elongate steel cutting bit body. Such cutting bits also comprise a hard (e.g., cemented (cobalt) tungsten carbide) insert affixed to the axial forward end of the cutting bit body. The bore of a holder (or block) retains (in a rotatable fashion or in a non-rotatable fashion) the cutting bit at its axial rearward end. During operation such as, for example, in a road planning application, a driven drum ca...

AI Technical Summary

Benefits of technology

[0011]In another form thereof, the invention is a cutting bit for impinging earth strata. The cutting bit comprises a highly wear-resistant elongate cutting bit body that has an axial forward end and an axial rearward end, an enlarged dimension head portion at the axial forward end and a reduced dimension shank portion at the axial rearward end. At least a part of the highly wear-resistant elongate cutting bit body comprises a hard component-matrix composite material to provide wear resistance. The cutting bit has a hard insert affixed to the head portion at the axial forward end of the cutting bit body.

Problems solved by technology

While the cutting bits that have the wide collar function in a satisfactory fashion, there is a drawback with these cutting bits.

This drawback is that the wide collar presents a greater volume or mass of material of the cutting bit that must pass through the earth strata.

This results in an increase in the resistance the cutting bit encounters upon impingement of the earth strata.

Such an increase in resistance results in an increase in energy necessary to break up the earth strata, which increases fuel consumption and overall operating costs, as well as decreases or reduces overall operational efficiency for the specific application.

By encountering more resistance, the cutting bit exhibits a higher rate of wear, which, in turn, causes the cutting bit to become blunter thereby reducing the overall cutting efficiency.

In the case of a road planing application, and there can be a great amount of time spent to change out an entire set of road planing bits on a road planing drum.

In the case where the cutting bit presents a wider profile or geometry, there is the tendency for the cutting bit to pulverize the coal upon impingement, which generates small particulates.

The use of a cutting bit with a wider profile results in a higher incidence of generating small particulates due to the increased resistance of the cutting bit impinging the substrate (e.g., vein of coal).

In a road planing operation such as planing asphaltic roadway material, the cutting bits may impact a manhole cover or the life during the course of the planing operation.

In a trenching operation, the cutting bits may encounter rocks or other very hard regions.

Free rotation about its central longitudinal axis maintains the geometric symmetry of the cutting bit about its central longitudinal axis, which typically results in a longer useful tool life.

Images