Handheld Sanding Device Shaft Coupling for Surface Adaptation

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Solution Overview

Problem

Conventional handheld grinders require manual adjustment to match the inclination of the sanding target surface, leading to eccentric wear and inefficient contact during sanding operations.

Innovation Solution

A handheld sanding device with a shaft coupling unit that includes a separation prevention ball and ball movement cavity, allowing the sanding unit to freely incline based on the power transmission unit, ensuring close contact and preventing eccentric wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the sanding unit is fixed rigidly to the power transmission unit, then the device structure is simple and easy to manufacture, but the sanding unit cannot adapt to different surface inclinations leading to eccentric wear

Engineering Contradiction:
Improveadaptation to surface inclinationVSAvoidshaft coupling unit structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sanding unit is made dynamically adjustable through the shaft coupling unit, which includes a rotating shaft portion that can rotate relative to the fixed shaft portion. This allows the sanding unit to adapt its inclination angle to match different sanding target surfaces, resolving the contradiction between adaptability and structural simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The shaft coupling unit is segmented into a fixed shaft portion (coupled to power transmission unit) and a rotating shaft portion (coupled to sanding unit), separated by the separation prevention ball. This segmentation enables independent movement of each part, allowing the sanding unit to adjust its angle while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the sanding unit is made freely adjustable, then close contact with the sanding target surface is improved, but the transmission of rotating force becomes less stable

Engineering Contradiction:
Improvecontact stabilityVSAvoidrotating force transmission
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The separation prevention ball acts as an intermediary element between the fixed shaft portion and the rotating shaft portion. It maintains stable power transmission while allowing controlled relative rotation, enabling the sanding unit to adjust to surface inclination without compromising the stability of rotating force transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system allows dynamic change of the inclination angle parameter of the sanding unit relative to the power transmission unit. The separation prevention ball enables this parameter change while maintaining continuous power transmission, resolving the contradiction between contact stability and force transmission stability.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If manual adjustment of inclination is required, then the device structure remains simple, but the operation becomes complex and time-consuming

Engineering Contradiction:
Improveautomatic inclination adjustmentVSAvoidshaft coupling mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The sanding unit performs self-adjustment of its inclination angle through the rotating shaft portion, which can rotate freely relative to the fixed shaft portion. The operator simply needs to apply light pressure, and the sanding unit automatically adapts to the target surface inclination, eliminating the need for manual adjustment mechanisms while maintaining simple operation.

Inventive Principle:
Principle #25Self-service

4Manufacturing precision

If the sanding unit is held rigidly at a fixed angle, then power transmission is efficient, but the sanding target surface experiences eccentric wear

Engineering Contradiction:
Improveuniformity of sanding surfaceVSAvoidrotating force transmission efficiency
Core Design Contradiction:
Manufacturing precisionVSPower

Solution Approach 1:

The shaft coupling unit provides dynamic angle adjustment capability, allowing the sanding unit to maintain optimal contact angle with the target surface. This dynamic adaptation ensures uniform sanding across the surface while the separation prevention ball maintains efficient power transmission, resolving the contradiction between sanding uniformity and power transmission efficiency.

Inventive Principle:
Principle #15Dynamics

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 device achieves stable and efficient sanding by allowing the sanding unit to adjust to the target surface inclination, preventing eccentric wear and improving the transmission of rotating force, while allowing for easy handling and adjustment of the sanding distance.

Implementation Method 1

a rotating shaft portion including an autonomous rotation block configured to be provided with a ball movement cavity into and on which the separation prevention ball is inserted and supported so that the separation prevention ball is reciprocated or inclined

Methodology Applied
Scientific EffectBall movement mechanism: Ball

Data Source

PatentEP3626393B1Handheld sanding device
Publication Date: 2023.05.10 JEON SANG NAM
  • EP3626393B1 patent drawingFigure 1
  • EP3626393B1 patent drawingFigure 2~3
  • EP3626393B1 patent drawingFigure 4

AI summary

A handheld sanding device according to the present invention includes: a power generation unit configured to generate rotating force for sanding operation; a power transmission unit configured to be coupled to the power generation unit, and to transmit the rotating force generated by the power generation unit; a sanding unit configured to be rotated by the rotating force, transmitted through the power transmission unit, in order to sand a sanding target surface; and a shaft coupling unit configured to connect the power transmission unit and the sanding unit to each other so that the sanding unit is freely inclined based on the power transmission unit, thereby improving the close contact between the sanding target surface and the sanding unit while making it easy to carry and also preventing the sanding target surface from being eccentrically worn during sanding operation.