Variable Shear Angle Scrap Cutter for Constant-Torque Cutting
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Solution Overview
Problem
Existing scrap cutters face challenges in achieving high-speed operation due to mechanical rigidity and inertia requirements, especially when cutting materials with varying shear angles, which leads to vibration and inefficiency.
Innovation Solution
A scrap cutter design with a gradually decreasing shear angle from start to end of cutting, utilizing a crank mechanism with constant driving torque, and optimized blade geometry to minimize inertia and vibration, allowing for efficient and high-speed cutting of materials within the cutting capacity limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a shear angle of 0 degrees or small shear angle is used, then the press capacity requirement is reduced, but the mechanical rigidity requirement increases and inertia increases making high speed operation unsuitable
Solution Approach 1:
The patent applies a dynamically variable shear angle that changes during the cutting stroke. The shear angle is larger at the beginning of cutting and gradually decreases toward the end, allowing the system to adapt to changing cutting conditions and maintain optimal performance across the entire cutting cycle.
Solution Approach 2:
The patent changes the geometric parameter of the shear angle during operation. By making the shear angle variable rather than constant, the system can optimize both force requirements and speed performance, resolving the contradiction between these two parameters.
2Force
If a large shear angle is used, then the press capacity requirement is reduced, but the stroke length increases making the apparatus larger and unsuitable for high speed operation
Solution Approach 1:
The patent uses a dynamic shear angle that varies during the cutting stroke. The shear angle is larger at the beginning where full stroke is needed and decreases as cutting progresses, allowing reduced overall stroke length while maintaining adequate cutting capability.
Solution Approach 2:
The cutting process is segmented into different phases with different shear angle requirements. The variable shear angle profile allows optimization for each phase of the cutting stroke, reducing the total stroke length needed compared to a constant large shear angle.
3Device complexity
If a constant shear angle is used, then the blade structure is simple, but the driving torque varies during cutting reducing efficiency
Solution Approach 1:
The patent implements a dynamic shear angle that varies during the cutting stroke, which optimizes the driving torque characteristics. This dynamic configuration maintains more constant torque requirements throughout the cutting cycle, improving efficiency despite increased structural complexity.
Solution Approach 2:
The patent changes the shear angle parameter during operation to optimize cutting efficiency. The variable parameter approach allows maintenance of constant driving torque, resolving the contradiction between structural simplicity and cutting efficiency.
4Manufacturing precision
If the moving blade swings during cutting, then the cut surface quality is improved, but left-right vibration is generated making high speed operation unsuitable
Solution Approach 1:
The patent applies a dynamic shear angle achieved through blade geometry design rather than physical swinging of the blade holder. This dynamic parameter variation improves cut surface quality without introducing the harmful vibrations associated with mechanical swinging, enabling high speed operation.
Data Source
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AI summary
A scrap cutter 50 is provided in a subsequent stage of the press machine 40 and cuts the scrap material fed from the press machine. The scrap cutter 50 includes: a slide 54 configured to be driven to reciprocate in the vertical direction by a Scotch yoke mechanism 57; an upper blade 55 attached to the slide 54; and a lower blade 56 attached to a frame 52 and configured to cut the scrap material in cooperation with the upper blade 55. A shear angle formed by the upper blade 55 and the lower blade 56 has an angle that gradually decreases from a start of cutting of the scrap material toward an end of cutting to allow the driving torque of the crankshaft 59 of the Scotch yoke mechanism 57 to be constant from the start of cutting to the end of cutting in cutting a scrap material of a cutting capacity limit.