Alternating Circular Saw Teeth for Wear Life and Breakage Resistance

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Solution Overview

Problem

Existing circular saw blades face a trade-off between wear life and durability, with increased rake, relief, and top bevel angles improving cutting efficiency but reducing durability, and vice versa, leading to premature failure when cutting abusive materials like wood with nails.

Innovation Solution

A circular saw blade design featuring alternating sets of efficient and robust teeth with distinct rake, relief, and top bevel angles, where the robust teeth have smaller angles for increased durability and the efficient teeth have larger angles for improved cutting efficiency, with the robust teeth receiving a greater percentage of the total chip load to inhibit cascading breakages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rake angle, relief angle, and top bevel angle are increased to improve cutting efficiency, then wear life increases but durability decreases

Engineering Contradiction:
Improvecutting efficiencyVSAvoiddurability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The saw blade is segmented into alternating sets of efficient teeth and robust teeth around its periphery. Each set serves a different function: efficient teeth with larger rake, relief, and top bevel angles optimize cutting speed and efficiency, while robust teeth with smaller angles provide durability and resistance to chipping when cutting abusive materials. This segmentation allows the blade to achieve both high productivity and reliability simultaneously.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the rake angle, relief angle, and top bevel angle are decreased to improve durability, then durability increases but wear life decreases

Engineering Contradiction:
ImprovedurabilityVSAvoidwear life
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The saw blade alternates between robust teeth designed for durability and efficient teeth designed for wear resistance and cutting speed. The robust teeth with smaller angles handle abusive materials without chipping, while the efficient teeth with larger angles maintain cutting speed and extend overall blade life through reduced wear.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If uniform tooth design is used to simplify manufacturing, then ease of manufacture increases but performance compromises both life and durability

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidoverall performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Different portions of the saw blade periphery are given different tooth characteristics. Alternate sets of teeth have distinct rake angles, relief angles, and top bevel angles optimized for their specific functions. This local differentiation of tooth geometry allows each section to perform its specialized role while maintaining overall blade functionality.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3718667B1Circular saw blade
Publication Date: 2023.08.23 BLACK & DECKER CORP
  • EP3718667B1 patent drawingFigure 1
  • EP3718667B1 patent drawingFigure 2
  • EP3718667B1 patent drawingFigure 3A~3B

AI summary

A circular saw blade includes a plurality of cutting teeth repeatedly alternating between a first set of cutting teeth and a second set of cutting teeth around the periphery of the saw blade. Each first set of cutting teeth includes at least two efficient cutting teeth, each second set of cutting teeth comprising at least ne robust cutting tooth. Each first set of teeth and each second set of teeth are configured such that, if one tooth in the first set of teeth breaks, the chip load in the immediately following second set of teeth increases by less than approximately 45%.