Rock Drill Bit Cutting Edge Projections for Faster Drilling

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Solution Overview

Problem

Existing drill bits experience slowed drilling speed due to the envelope line maintaining a short contact surface, which limits drilling progress, especially in materials like concrete and rock.

Innovation Solution

The drill bit design incorporates projections on the cutting edge that apply force at a point in the material, acting as breakers or crack formers, increasing drilling speed by providing additional breakage points and optimizing the contact pressure profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If recesses are formed in the cutting edge, rake face, and/or clearance face to optimize contact pressure profile, then drilling properties are improved, but the outer surface remains unchanged and drilling speed is not increased

Engineering Contradiction:
Improvedrilling propertiesVSAvoiddrilling speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

Instead of removing material to form recesses as in prior art, the invention inverts the approach by adding material to form projections that extend beyond the cutting edge in the feed direction. This inversion transforms the cutting edge geometry from concave to convex, creating a point-like force application that acts as a breaker and crack inducer, thereby increasing drilling speed while maintaining optimized contact pressure profile

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention applies local quality by creating projections at specific locations on the cutting edge where point-like force application is most effective. The projections are strategically positioned to act as breakers and crack inducers in the material being drilled, concentrating the cutting action at critical points rather than distributing it uniformly across the cutting edge

Inventive Principle:
Principle #3Local quality

2Reliability

If a protective line is formed above the drill tip, then the cutting edge is protected, but the contact area is shortened and drilling speed is slowed down

Engineering Contradiction:
Improvecutting edge protectionVSAvoiddrilling speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The invention inverts the protective line concept by replacing it with projections that extend beyond the cutting edge. Instead of a protective line that shortens contact area, the projections create point-like force application areas that actively engage the material as breakers and crack inducers, transforming a protective feature into an active cutting enhancement

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If material is removed to form recesses in the cutting edge, then contact pressure profile is optimized, but additional manufacturing effort is required and material is wasted

Engineering Contradiction:
Improvecontact pressure profileVSAvoidmanufacturing effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention inverts the material removal approach by using material addition to form projections. Instead of removing material to create recesses, the projections are formed by adding material that extends beyond the cutting edge in the feed direction, maintaining optimized contact pressure profile while potentially simplifying the manufacturing process

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention applies parameter changes by altering the geometry of the cutting edge from recessed to protruding. The projections change the physical parameters of the cutting edge, creating a convex geometry that extends beyond the original cutting edge surface, thereby optimizing the contact pressure profile through geometric transformation

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The use of projections on the cutting edge significantly enhances drilling speed by applying punctiform force, effectively breaking material and improving drilling efficiency.

Implementation Method 1

the projection ensures a point-like force application of the cutting edge into the material being machined. In other words, the projection acts as a breaker and/or crack inducer

Methodology Applied
Scientific EffectPoint-like force application: Impact Force

Data Source

PatentEP2848338B1Drilling head and drilling bit
Publication Date: 2022.05.11 DREBO WERKZEUGFABRIK GMBH
  • EP2848338B1 patent drawingFigure 1~4
  • EP2848338B1 patent drawingFigure 5~6c
  • EP2848338B1 patent drawingFigure 7

AI summary

The invention relates to a drill head insert or drill head attachment, in particular a drill plate made of hard metal, for a rock drill, with cutting edges (20, 20a) formed on the feed side, which recede backwards from a drill bit (18) to an outer side (12, 14) of the drill plate (10) extend. The invention also relates to a drilling plate (10), which is essentially roof-shaped in side view and has a free surface (24, 24a) on the Cutting edge (20, 20a) abuts against a rake face (22, 22a). A substantially smooth progression of the cutting edge (20, 20a) is interrupted by at least one projection (30, 30a, 30b) which protrudes beyond the cutting edge (20, 20a) in the direction of feed, the rake face (22, 22a) having convex rake face Has projections (30b).