Modular Self-Feed Bit Head for Low-Torque Fast Boring

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Solution Overview

Problem

Existing self-feed bits are not sufficiently durable, efficient, or effective in reducing torque and increasing cutting speed, and they lack interchangeable and modular designs for improved usability and packaging efficiency.

Innovation Solution

A self-feed bit system with a sector-shaped cutting head and radially extending lip, featuring a rake angle of at least 40°, a removable and interchangeable cutting blade, and a partially threaded tip with a pitch of less than or equal to 1.2 mm, along with a modular design allowing for tool-free attachment and interchangeable cutting heads, reduces torque and enhances durability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional self-feed bits are used, then basic cutting function is provided, but durability and cutting efficiency are insufficient

Engineering Contradiction:
ImprovedurabilityVSAvoidcutting efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The cutting head is divided into modular components including a replaceable cutting blade, teeth, and lip structure. This segmentation allows individual components to be optimized for specific functions (cutting, scoring, feeding) while enabling replacement of only worn components rather than the entire bit, thereby improving durability and cutting efficiency simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cutting blade and teeth are made from composite or specialized materials (such as carbide-tipped or cermet materials) that combine hardness for durability with toughness for cutting performance. This material selection resolves the contradiction by providing both extended service life and effective cutting capability

Inventive Principle:
Principle #40Composite materials

2Productivity

If a threaded tip with fine pitch is used, then feeding efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvefeeding efficiencyVSAvoidthread pitch precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The thread pitch is optimized to 1.2 mm or finer, representing a specific parameter change that balances feeding efficiency with manufacturability. This precise pitch value provides sufficient thread engagement for effective self-feeding while remaining within achievable manufacturing tolerances for standard machining processes

Inventive Principle:
Principle #35Parameter changes

3Productivity

If a rake angle of at least 40° is used, then cutting speed increases, but edge strength may be reduced

Engineering Contradiction:
Improvecutting speedVSAvoidedge strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The cutting blade and teeth utilize composite or advanced materials (carbide, cermet) that maintain high edge strength even with a aggressive 40° or greater rake angle. These materials inherently combine hardness and toughness, allowing the rake angle to be optimized for cutting speed without sacrificing the edge strength needed for durability

Inventive Principle:
Principle #40Composite materials

4Adaptability or versatility

If interchangeable cutting heads are provided, then adaptability improves, but device complexity increases

Engineering Contradiction:
ImproveinterchangeabilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cutting head is designed as a modular, self-contained unit that attaches to the shank through a standardized interface. This segmentation enables interchangeability of cutting heads for different applications while keeping each individual head relatively simple in design, thus improving adaptability without proportionally increasing overall system complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shank and cutting head interface is designed with universal features (such as standardized threading or attachment mechanisms) that allow a single shank to accommodate multiple cutting head variants. This universality provides adaptability across different cutting applications while maintaining a consistent, relatively simple attachment system

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4357091A1Self-feed bit system
Publication Date: 2024.04.24 BLACK & DECKER CORP
  • EP4357091A1 patent drawingFigure 1
  • EP4357091A1 patent drawingFigure 2A
  • EP4357091A1 patent drawingFigure 2B

AI summary

A self-feed bit system includes a shank extending along an axis and configured to be coupled to a tool holder of a power tool and a cutting head couplable to the shank and including a sector shaped base. A radially extending lip is at a leading edge of the sector shape facing in a cutting direction and includes a rake face facing the cutting direction at a rake angle relative to the axis. A radially extending cutting blade is coupled to the radially extending lip and extends axially forward from the base at a first height. An at least partially threaded tip is coupled to the shank and extends axially forward of the cutting blade. Two or more teeth are positioned on a perimeter of the base trailing the cutting blade. Each tooth extends axially forward from the base at a second height that is less than the first height.