Hand Grinder Polishing Disk Attachment Mechanism

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Solution Overview

Problem

Existing hand grinder systems face issues with the secure attachment and detachment of polishing disks, leading to potential separation during use due to loose fasteners and vibration, and have complex structures that increase manufacturing costs and vibration risks.

Innovation Solution

A device featuring a stopper body with safety keys, rotation keys, and vibration-preventing pads allows for easy one-touch attachment and detachment of a polishing disk, using a power-transmitting member and locking mechanism to prevent separation and reduce vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a nut or bolt is used to fasten the polishing disk to the grinder body, then the polishing disk can be attached to the grinder body, but the clamping force decreases due to friction and vibration, causing the fastener to become loose and the polishing disk to separate during work

Engineering Contradiction:
Improveattachment reliabilityVSAvoidclamping force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The invention employs a dynamic locking mechanism where the set screw engages with an inclined surface on the rotary shaft. As the rotary shaft rotates, the inclined surface automatically pushes the set screw deeper into the locking position, creating a self-tightening effect that maintains clamping force despite vibration and friction. This dynamic response to rotational motion resolves the contradiction between initial attachment and sustained clamping force.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The inclined surface is designed in advance to compensate for the loosening effect of vibration and friction. By positioning the set screw on the inclined surface, the system pre-establishes a mechanism that will automatically counteract any tendency toward loosening during operation, ensuring reliable attachment throughout the work cycle.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a fixed cover is mounted near the polishing disk to prevent separation, then safety against disk separation is improved, but the device complexity increases and vibration may occur

Engineering Contradiction:
Improvesafety against separationVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the safety function from a separate fixed cover component and integrates it directly into the rotary shaft through the inclined surface and set screw mechanism. This eliminates the need for an additional cover component while maintaining the safety function, thereby reducing device complexity while preventing disk separation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The locking mechanism is merged with the rotary shaft structure itself, combining the functions of rotation transmission and disk retention into a single integrated component. This merger eliminates separate safety components and reduces overall structural complexity while maintaining reliable disk attachment.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a fixing holder with screw fastening is used to attach the disk holder to the grinder body, then the disk can be prevented from separating, but the attachment and detachment process becomes more time-consuming and complex

Engineering Contradiction:
Improvedisk retentionVSAvoidreplacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention segments the retention mechanism into a simple set screw and inclined surface pair, separate from the main rotary shaft. This segmentation allows the set screw to be independently adjusted and tightened without affecting other components, enabling rapid attachment and detachment while maintaining reliable disk retention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using a complex multi-screw fastening system that requires sequential tightening, the invention inverts the approach by using a single set screw on an inclined surface that automatically engages and locks during rotation. This inverted mechanism simplifies the attachment process to a single tightening action while maintaining secure retention.

Inventive Principle:
Principle #13The other way round (Inversion)

4Reliability

If safety keys fixed by ball plungers are used to prevent disk separation, then disk retention is improved, but abrasion from long-term use causes the polishing disk to separate

Engineering Contradiction:
Improvedisk retentionVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention replaces the ball plunger mechanical system with a friction-based set screw mechanism on an inclined surface. This substitution eliminates the wear-prone ball plunger components and their associated holes, replacing them with a simpler friction-based locking system that has longer service life and maintains retention reliability over extended use.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

5Object-affected harmful factors

If a plate spring is used to prevent vibration, then vibration reduction is improved, but long-term use causes the spring function to weaken

Engineering Contradiction:
ImprovevibrationVSAvoidservice life
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The invention extracts the vibration control function from a separate plate spring component and integrates it directly into the set screw mechanism through the inclined surface. The inclined surface itself provides the vibration-resistant locking action, eliminating the need for a separate spring component and its associated service life limitations.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3109001B1Device for detaching/attaching hand grinder polishing disk
Publication Date: 2019.05.08 E&Q ONE TOUCH
  • EP3109001B1 patent drawingFigure 1
  • EP3109001B1 patent drawingFigure 2~3
  • EP3109001B1 patent drawingFigure 4a~4b

AI summary

The present invention relates to a device that enables a polishing disk which is consumable goods used for cutting, polishing and grinding an object in a state of being fixed to a rotary shaft of a grinder body to be easily attached to or detached from a hand grinder in a simple way. In addition, the device prevents the polishing disk from being separated from the grinder in the middle of work, reducing vibration. The device includes: a grinder body including a rotary shaft which is driven by an operation of electric motor or air pressure; a power-transmitting member that includes catching protrusions protruding from a top end of a main body of the power-transmitting member, a flange formed below the catching protrusions, and a hexagonal pillar formed below the flange and that is fixed to the rotary shaft of the grinder body by a fixing bolt; a stopper body including a hexagonal hole that is formed at the center of the stopper body to receive the power-transmitting member therein, and arc-shaped mounting grooves that are formed at the outside of the hexagonal hole to face each other; an upper rotary plate and a lower rotary plate that are mounted on a top of the stopper body; and a disk holder that includes an upper fixing ring and a lower supporting plate which are provided to fix an abrasive therebetween and that is assembled with the power transmitting member.