Swing Motor Electric Grinder Reciprocating Head Design
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Solution Overview
Problem
Existing nail and hard skin grinders using rotary motors often cause injury due to excessive grinding, and are difficult for children or individuals with poor dexterity to operate safely.
Innovation Solution
A swing motor-driven electric grinder with a unique magnetic circuit design and a reciprocating grinding head that uses alternating pulses to generate torque, allowing for a grinding head that swings back and forth, reducing the risk of injury and enabling safe operation by minimizing skin contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotary motor is used to drive the grinding head at high speed, then the grinding efficiency is improved, but the risk of skin injury increases due to excessive grinding
Solution Approach 1:
The patent transitions from a rotary motor producing continuous rotation to a swing motor producing reciprocating motion. The swing motor drives the grinding head to swing back and forth between two extreme positions, creating a dynamic reciprocating motion pattern. This dynamic motion reduces skin injury risk because the grinding head does not continuously press against one location, yet maintains grinding efficiency through high-frequency reciprocation.
Solution Approach 2:
The swing motor generates periodic reciprocating motion through alternating magnetic poles that periodically attract and repel the permanent magnets. The control circuit produces alternating current pulses that create periodic magnetic field reversals, causing the swing arm to oscillate between extreme positions. This periodic action ensures the grinding head contacts different areas sequentially, preventing excessive grinding at any single point while maintaining overall productivity.
2Measurement precision
If a rotary motor with reducer is used to rotate the sand paper at low speed, then the control precision is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the reducer component from the motor system. Instead of using a rotary motor with a separate reducer mechanism, the invention integrates the speed control function directly into the swing motor's electromagnetic design. The swing motor's inherent reciprocating motion and magnetic circuit configuration provide the necessary speed control without requiring additional mechanical reduction gears, thereby simplifying the overall device structure while maintaining control precision.
Solution Approach 2:
The patent replaces the mechanical reducer system with an electromagnetic control system. The swing motor uses electromagnetic fields and magnetic circuits to control the reciprocating motion directly, substituting mechanical gear reduction with electromagnetic force control. This substitution eliminates complex mechanical transmission components while achieving precise control over the grinding head's motion characteristics.
3Ease of manufacture
If the grinding head rotates continuously, then the manufacturing simplicity is improved, but the ease of operation deteriorates for users with limited dexterity
Solution Approach 1:
The swing motor creates dynamic reciprocating motion that automatically adjusts to the workpiece geometry. The grinding head swings back and forth, naturally adapting to contours and curves without requiring user skill to maintain consistent contact. This dynamic motion pattern makes the tool easier to operate for users with limited dexterity while maintaining manufacturing simplicity through the swing motor's straightforward electromagnetic design.
Solution Approach 2:
The reciprocating motion of the swing motor provides self-regulating grinding action. The grinding head automatically moves between extreme positions, ensuring continuous contact with the workpiece surface without requiring precise user control. This self-service characteristic reduces the skill level needed for safe and effective operation, making the device more accessible to users with limited dexterity while keeping the motor structure relatively simple.
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
The solution provides a safer and more effective grinding mechanism with reduced power consumption, larger torque, and a longer service life, allowing for precise nail and hard skin grinding without harming surrounding skin, even for users with limited dexterity.
Implementation Method 1
a motor is an electromagnetic device that converts electric energy according to the law of electromagnetic induction
Implementation Method 2
a second yoke mounted at one end of the inner arm close to the U-shaped yoke; and a first permanent magnet, a second permanent magnet, a third permanent magnet and a fourth permanent magnet fixedly mounted on the second yoke
Data Source
AI summary
Provided is an electric grinder. The grinder includes a swing motor and a grinding head driven by the swing motor. The swing motor further includes a U-shaped yoke, four permanent magnets and a swing arm. Alternating magnetic poles can be generated at end faces of the two legs under control of a control circuit. The four permanent magnets are sequentially distributed on the same circumference of a circle having the fulcrum as a center. The control circuit generates alternating pulses with adjustable pulse widths, which change the moving direction of the permanent magnets alternately, so that the permanent magnets move back and forth. The swing arm drives the grinding head to reciprocate at a high speed with small swinging amplitude, thereby cleaning the body surface (skin, nails or the like) of living bodies including human beings and animals.