Band Saw Blade Tooth Geometry for High-Impact Structural Cutting

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Solution Overview

Problem

Band saw blades face challenges when cutting large structural workpieces, such as I-beams and tubes, due to high-impact loading, tooth damage, and blade pinching, which reduces their useful life and requires frequent replacement.

Innovation Solution

A band saw blade design featuring teeth with a robust tooth form, varying pitch distances, and a multi-level set pattern, along with an extra-wide kerf, to minimize vibration, accommodate changing tooth engagement lengths, and prevent blade pinching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a band saw blade is used to cut large structural workpieces with high-impact loading, then the cutting capability is improved, but tooth damage occurs frequently reducing blade life

Engineering Contradiction:
Improvecutting capabilityVSAvoidblade life
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The blade is segmented into multiple teeth with varying pitch distances, where each tooth can independently engage and disengage from the workpiece. This segmentation allows the blade to distribute impact loads across multiple teeth rather than concentrating stress on single teeth, thereby reducing tooth damage and extending blade life while maintaining cutting capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pitch distance between adjacent teeth is varied along the blade circumference, creating non-uniform spacing patterns. This parameter change allows different regions of the blade to accommodate changing tooth engagement lengths during cutting, optimizing performance for both high-impact cutting and extended blade life

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the number of teeth engaging the workpiece increases to handle high-impact loading, then cutting stability is improved, but tooth damage risk increases due to increased engagement regions

Engineering Contradiction:
Improvecutting stabilityVSAvoidtooth damage resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

Different regions of the blade have different pitch distances, creating local variations in tooth engagement characteristics. Some regions have closer spacing for stability, while other regions have wider spacing to reduce simultaneous tooth engagement, thereby balancing cutting stability with tooth damage resistance

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the tooth engagement length changes significantly during cutting, then adaptability to workpiece geometry is improved, but cutting efficiency decreases due to deviation from ideal tooth engagement range

Engineering Contradiction:
Improveadaptability to workpiece geometryVSAvoidcutting efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The variable pitch pattern creates a dynamic tooth engagement system where the number of engaged teeth changes continuously along the blade circumference. This dynamic adaptation allows the blade to maintain optimal cutting efficiency across varying engagement lengths by ensuring that sufficient teeth are always engaged, even when geometry changes

Inventive Principle:
Principle #15Dynamics

4Device complexity

If a standard kerf width is used, then blade simplicity is maintained, but blade pinching occurs reducing blade life

Engineering Contradiction:
Improveblade design simplicityVSAvoidblade pinching resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The blade design incorporates an asymmetric tooth configuration with varying pitch distances rather than uniform spacing. This asymmetry creates an extra-wide kerf that prevents material from closing in on the blade during cutting, eliminating blade pinching while maintaining relatively simple overall blade design

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3753661B1Band saw blade for cutting structural workpieces
Publication Date: 2022.04.27 BLACK & DECKER CORP
  • EP3753661B1 patent drawingFigure 1A~1B
  • EP3753661B1 patent drawingFigure 1C
  • EP3753661B1 patent drawingFigure 1D~1F

AI summary

A band saw blade (100) having a blade body (101) including a cutting edge (102) defined by a number of teeth (110) spaced relative to each other. Each tooth includes a tip (112), a rake face (114) formed on one side of the tip, a primary clearance surface (116) formed on an opposite side of the tip relative to the rake face and defining a primary relief angle (α1), a secondary clearance surface (118) formed on an opposite side of the primary clearance surface relative to the tip and defining a secondary relief angle (α2) that is greater than the primary relief angle, a tertiary clearance surface (120) formed on an opposite side of the secondary clearance surface relative to the primary clearance surface and defining a tertiary relief angle (α3) that is greater than the secondary relief angle, and a protrusion (122) formed between the secondary clearance surface and the tertiary clearance surface and having a curvilinear shape. The protrusion is defined by a concave surface and a convex surface. The concave surface extends from the secondary clearance surface to the convex surface, and the convex surface extends from the concave surface to the tertiary clearance surface