Four-Arm Cutting Head for Drill Bit Force Distribution

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Solution Overview

Problem

Conventional drill bits for concrete and rock drilling often experience uneven distribution of hammering force, leading to cutting edge breakage and increased power requirements, which reduces durability and efficiency.

Innovation Solution

A cutting head design featuring four identically shaped cutting arms radially extending from a central point, with equiangular spacing and curved transitions, distributing force evenly and reducing stress concentrations, while maintaining low power requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional drill bits use two opposing main cutting arms with auxiliary cutting edges, then the cutting head can remove material effectively, but the hammering force is unevenly distributed leading to cutting edge breakage

Engineering Contradiction:

Improvecutting edge durabilityVSAvoidhammering force distribution

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The cutting head is segmented into four substantially identically shaped cutting arms extending radially from a common central axial point, with each arm having equiangularly spaced cutting edges. This segmentation distributes the hammering force evenly across four cutting edges rather than concentrating it on two main cutting edges, preventing cutting edge breakage and improving reliability.

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If conventional drill bits use two main cutting arms, then the power requirement is minimized, but the cutting edge breakage increases due to uneven force distribution

Engineering Contradiction:

Improvepower requirementVSAvoidcutting edge durability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The invention departs from the conventional symmetric two-arm design by implementing a four-arm configuration with equiangularly spaced cutting edges. This asymmetric redistribution of cutting elements changes the force distribution pattern, allowing even force distribution across four edges while maintaining acceptable power requirements for the drill operation.

Inventive Principle:

Principle #4Asymmetry

3Productivity

If auxiliary cutting edges are added to conventional drill bits, then material removal capability is improved, but the complexity of the cutting head increases

Engineering Contradiction:

Improvematerial removal capabilityVSAvoidcutting head structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The cutting head employs four substantially identically shaped cutting arms with equiangularly spaced cutting edges, creating a homogeneous and symmetric structure. This uniform design simplifies manufacturing compared to conventional asymmetric two-arm designs with auxiliary edges, as all four arms can be produced using the same molding or machining process, reducing overall device complexity while improving material removal capability.

Inventive Principle:

Principle #33Homogeneity

Data Source

PatentUS9284787B2Drill bit and cutting head for drill bit

Publication Date: 2016.03.15 BLACK & DECKER CORP

AI summary

A cutting head for a drill bit comprises four substantially identically shaped cutting arms extending radially from a common central axial point, each cutting arm comprising a cutting edge extending, outwardly and axially backwards from the common central axial point. The cutting edges are equianguiarly spaced apart from each other about the central axis of the cutting head. Each cutting, arm further comprises a side chamfer extending between its radially outer face and its rotationally trailing side face.