Hole Saw Tooth Geometry for Reduced Breakage Under Offset Cutting
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Solution Overview
Problem
Conventional saw blades experience tooth breakage due to reduced blade body width, which increases stress and likelihood of tooth loss during cutting, especially when teeth are offset or have varying heights, leading to reduced saw blade lifespan.
Innovation Solution
A saw blade design with uniformly sized teeth, optimized pitch distances, and varying gullet depths and offsets, featuring two distinct tooth geometries for lighter and heavier set teeth to distribute stress evenly and prevent binding, thereby enhancing tooth strength and reducing breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of the blade body is decreased to increase cutting speed, then cutting speed is improved, but tooth strength deteriorates due to reduced material and higher stresses
Solution Approach 1:
The patent applies local quality by providing teeth with varying gullet depths - deeper gullets for teeth experiencing higher stresses and shallower gullets for teeth with lower stresses. This localized variation in tooth geometry optimizes strength distribution across the blade body, allowing thinner blade sections to maintain adequate tooth strength while enabling higher cutting speeds.
Solution Approach 2:
The patent changes geometric parameters of the teeth, specifically the gullet depth, to optimize performance. By varying the gullet depth parameter across different teeth positions, the design accommodates different stress conditions while maintaining overall blade thinness for high-speed cutting.
2Productivity
If teeth are offset from the blade body to improve cutting performance, then cutting efficiency is improved, but tooth breakage risk increases due to higher moments on extended teeth
Solution Approach 1:
The patent applies local quality by providing different gullet depths for offset teeth versus non-offset teeth. Teeth that are offset from the blade body centerline receive deeper gullets to compensate for the increased moment arm and higher bending stresses, while centrally located teeth have shallower gullets. This localized adaptation maintains reliability across all teeth positions.
3Productivity
If teeth have varying tooth tip heights to optimize cutting action, then cutting performance is improved, but stress distribution becomes uneven increasing breakage likelihood
Solution Approach 1:
The patent applies local quality by varying gullet depths according to the specific position and function of each tooth. Rather than uniformly reducing tooth height for performance, the design provides deeper gullets for teeth that experience higher stresses due to their position or function, while maintaining appropriate geometry for teeth with lower stress loads. This localized compensation ensures uniform stress distribution across all teeth.
Data Source
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AI summary
A saw blade (100) can include a blade body (114) having a cutting edge (101) defined by multiple teeth (102-112). The teeth can be disposed in a repeating pattern including a raker tooth (106), a first set tooth (102) having a light offset to a right side of the blade body, a second set tooth (104) having a heavy offset to the left side of the blade body, a second raker tooth (112), a third set tooth (108) having a light offset to the left side, and a fourth set tooth (110) having a heavy offset to the right side of the blade body. Each tooth can include a tip, rake face, gullet having a gullet depth, and one or more clearance surfaces. The pitch distance and gullet depth of the heavy offset teeth can be less than the pitch distances and gullet depths of the remaining teeth to provide an increased amount of strength for the heavy offset teeth.