Prism-Shaped Handsaw Teeth for Reduced Chip Clogging
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Solution Overview
Problem
Conventional handsaws with triangular teeth suffer from chip clogging due to tapered gullets, leading to deteriorated cutting performance, and struggle to maintain a fine pitch and large cutting edge area, resulting in increased cutting resistance.
Innovation Solution
A handsaw design featuring a combination of crosscutting teeth of triangular or trapezoidal prism shape and ripping teeth of parallelogram-based prism shape, where adjacent teeth rise at a constant angle, ensuring a consistent space between them, which reduces chip clogging and enhances cutting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If triangular teeth are used with tapered gullets, then the saw can be manufactured with simple geometry, but chip clogging occurs and cutting performance deteriorates
Solution Approach 1:
The patent changes the fundamental geometric parameter of the tooth shape from triangular to prism-shaped with constant cross-section. This parameter change transforms the tapered gullet geometry into a constant-width space between teeth, preventing chip clogging while maintaining manufacturing feasibility through standard sawing processes
Solution Approach 2:
The patent introduces curvature by forming the prism-shaped teeth with rounded edges and constant cross-sectional area, creating a cylindrical or prismatic geometry instead of sharp triangular points. This curved/rounded geometry prevents chip accumulation in the spaces between teeth while maintaining cutting effectiveness
2Strength
If triangular teeth with large base width are used, then tooth strength is increased, but pitch becomes coarse and cutting resistance increases
Solution Approach 1:
The patent changes the dimensional parameters by maintaining a constant tooth width (cross-section) along the entire tooth length rather than having a wide base that tapers to a point. This parameter change allows for finer pitch arrangement while maintaining adequate tooth strength through the constant cross-sectional geometry
Solution Approach 2:
The patent transitions from two-dimensional triangular tooth cross-sections to three-dimensional prism-shaped teeth with constant cross-section along the length. This dimensional change allows the teeth to be arranged more densely (finer pitch) while maintaining structural integrity through the extended constant-width geometry
3Device complexity
If triangular teeth are used, then the saw blade can be kept simple in structure, but the space between teeth tapers and clogs with chips
Solution Approach 1:
The patent changes the geometric parameter of the tooth from triangular (tapered) to prism-shaped (constant cross-section). This parameter change ensures that the space between adjacent teeth remains constant in width along the entire length, preventing chip clogging without significantly increasing structural complexity
Solution Approach 2:
The patent applies rounded or curved geometry to the prism-shaped teeth, creating constant cross-sectional areas that prevent chip accumulation. This curved geometry approach maintains relative simplicity while effectively eliminating the tapering problem that causes chip clogging in triangular teeth
Data Source
AI summary
A handsaw is provided with which chip clogging can be reduced significantly, the pitch of the tooth points can be made fine, the cut end face, called “top edge”, of each tooth can be increased in area, and moreover, cutting resistance is kept small and good cutting performance is ensured. The handsaw has a plurality of saw teeth arranged on a longitudinal edge (21) of a saw blade (20). The saw teeth are configured as a combination of crosscutting teeth (X) of triangular or trapezoidal prism shape and ripping teeth (Y) of parallelogram-based prism shape. The prism-shaped teeth constituting the crosscutting teeth (X) and the ripping teeth (Y) are configured such that at least adjacent prism-shaped teeth rise at a same rising angle (θ) from an edge surface (21a) of the longitudinal edge (21) of the saw blade (20), to cause a space (S) between the adjacent prism-shaped teeth to be constant in a rising direction in which the teeth rise.