Counter-Rotating Abrasive Wheels with Chamfered Edges
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Solution Overview
Problem
Existing electric abrasive sharpeners are expensive due to the need for heavy-duty motors to achieve adequate torque and often cause kickback during use, while also lacking an optimal sharpening surface.
Innovation Solution
The use of counter-rotating abrasive wheels with raised interconnecting threads and lead-in, lead-out chamfers, combined with an economical drive train featuring a unique array of gears and belts, allows for efficient sharpening with a smaller motor, reducing kickback and increasing the exposed sharpening surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If heavy duty electric motors are used to achieve adequate torque, then sharpening effectiveness is improved, but device cost and complexity increase
Solution Approach 1:
The abrasive wheels use convex spherical surfaces instead of flat surfaces, which concentrate the grinding force on a smaller contact area at the apex of the sphere. This curvature allows a smaller motor to generate sufficient torque because the force is more efficiently concentrated on the blade edge during sharpening.
Solution Approach 2:
The abrasive wheel surface is segmented into multiple abrasive grains distributed across the convex surface. This segmentation allows the grinding action to be distributed across many small contact points, reducing the peak force requirement on any single point and allowing a smaller motor to effectively drive the wheels.
2Ease of manufacture
If flat abrasive wheel surfaces are used, then manufacturing simplicity is improved, but sharpening surface area exposed to the blade is reduced
Solution Approach 1:
The patent uses convex spherical surfaces on the abrasive wheels instead of flat surfaces. The spherical geometry naturally presents a larger curved surface area to the blade during sharpening, increasing the effective contact area between the abrasive wheel and the blade edge that needs sharpening.
3Device complexity
If traditional single-direction rotating wheels are used, then device simplicity is improved, but kickback occurs during sharpening
Solution Approach 1:
The patent uses counter-rotating wheels where the two abrasive wheels rotate in opposite directions. This inversion of the traditional single-direction rotation creates opposing forces that cancel out the kickback effect, as one wheel's kickback tendency is counterbalanced by the other wheel rotating in the opposite direction.
4Area of stationary object
If convex abrasive wheel surfaces are used, then sharpening surface area is improved, but manufacturing precision requirements increase
Solution Approach 1:
The abrasive grains are uniformly distributed across the convex spherical surface, creating a homogeneous abrasive layer. This homogeneity ensures consistent sharpening performance across the entire surface area, making the convex geometry practical despite the increased manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables effective sharpening with a smaller, more economical motor, reducing costs and eliminating kickback while providing a larger sharpening surface for improved results.
Implementation Method 1
an electric motor mounted in the housing for rotation of the abrasive wheels
Implementation Method 2
counter-rotating abrasive wheels with raised interconnecting threads
Data Source
AI summary
An electric abrasive sharpener for sharpening edges having pairs of interlocking abrasive wheels formed with opposite abrasive helical threads. Each end of the threads respectively has lead-in section and lead-out section having chamfer edge portion to eliminate kickback. The abrasive wheels of the sharpener is driven by a single phase AC motor connected to a motor drive that steps down the rotational speed of the output shaft of the motor to rotate the abrasive wheels with increased torque.