Shear Blade Surface Profiling for Stress Distribution
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Solution Overview
Problem
Existing shear blades for cutting devices face issues with cutting power, stability, and durability due to complex structures and stress peaks, leading to material fractures and reduced durability.
Innovation Solution
A shear blade design featuring a first surface portion extending at a small acute angle α, a second surface portion at a larger acute angle β, and a third surface portion at an even larger acute angle γ, with surface profiling on the second and third portions to enhance cutting power and reduce pressure on the cutting edge, eliminating the need for clamping claws and minimizing stress peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a complex structure with clamping claws and multiple form closures is used to secure the cutting insert, then the cutting insert can be firmly held, but the production time and production costs increase, and the durability decreases due to stress peaks causing material fracture
Solution Approach 1:
The patent removes the complex clamping claw system and multiple form closures from the design. Instead, it uses a simplified single form closure at the lower end of the seat that provides sufficient holding strength without the additional complexity of multiple fastening elements, thereby reducing production time and eliminating stress concentration points
Solution Approach 2:
The patent combines the holding function and the stress distribution function into a single integrated form closure design. The beveled form-closure face simultaneously secures the cutting insert and distributes forces evenly, eliminating the need for separate clamping mechanisms and reducing the number of stress concentration points
2Shape
If a pointed blade insert structure is used, then the cutting edge can be sharp, but the risk of breakage increases due to stress peaks at the tips during rotation and cutting
Solution Approach 1:
The patent designs the blade insert with a rounded lower end and a beveled form-closure face that distributes forces evenly before they reach the cutting edge. This preemptive force distribution prevents stress peaks from developing at the cutting edge during operation, thereby preventing breakage while maintaining sharpness
Solution Approach 2:
The patent changes the geometric parameters of the blade insert by providing a rounded lower end instead of a pointed one, and by creating a beveled form-closure face with specific angles. This geometric modification redistributes the stress field during cutting, eliminating stress concentrations at the cutting edge while preserving the sharp cutting capability
3Device complexity
If the outer surface is designed as a single straight surface, then the structure is simple, but the cutting power is insufficient and pressure is not conserved in the region of the cutting edge
Solution Approach 1:
The patent segments the outer surface into multiple portions with different orientations (first surface portion at angle α, second surface portion at angle β, third surface portion at angle γ). This segmentation allows each surface portion to contribute differently to force distribution and pressure conservation, with the angles specifically designed to maintain pressure in the cutting edge region while simplifying the overall structure compared to complex curved surfaces
Data Source
AI summary
A shear blade is for a portable hydraulic cutting device having a blade body. The blade body has assembly and cutting regions, with a cutting edge in the cutting region. A contact surface is on one side of the cutting edge for an additional shear blade. An outer surface on the other side of the cutting edge acts on the object to be cut. A first surface portion of the outer surface extends away from the cutting edge along an orthogonal, which meets the contact surface at the cutting edge, or at an acute angle α relative to the orthogonal. A second surface portion connects to the first surface portion at an acute angle β to the orthogonal. A third surface portion connects to the second surface portion at an acute angle γ to the orthogonal. Angle α is smaller than angle β, which is smaller than angle γ.