Orbital Sander Counterweight Layout for Lower Contact Vibration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing power tools with eccentric motion for surface finishing experience increased vibration due to imbalance and external forces during sanding, which affects the surface finish quality and user comfort.

Innovation Solution

The power tool incorporates a counterweight positioned at a specific offset angle relative to the orbit radius axis and close to the sanding surface, coupled with a counterforce mass member, to counteract imbalance and reduce vibration levels by up to 40%.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the counterweight is positioned close to the sanding surface at a small offset angle, then vibration during workpiece contact is reduced, but the device complexity increases

Engineering Contradiction:
Improvevibration during workpiece contactVSAvoidcounterweight arrangement complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The counterweight is strategically positioned close to the sanding surface at a small offset angle relative to the orbit radius axis. This positioning allows the counterweight to generate a counterforce that directly opposes the external resistance forces generated during sanding operations, effectively reducing vibration while maintaining a relatively simple structural implementation.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Ease of operation

If the counterweight is positioned to counteract imbalance, then user comfort improves, but surface finish quality deteriorates due to increased vibration during sanding

Engineering Contradiction:
Improveuser comfortVSAvoidsurface finish quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent optimizes the offset angle and mass of the counterweight to achieve a balance between user comfort and surface finish quality. By positioning the counterweight at a predetermined offset angle and selecting an appropriate mass, the system reduces vibration during sanding operations, thereby improving surface finish quality while maintaining user comfort through effective imbalance counteraction.

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces tool vibration during operation, improving surface finish quality and user experience by maintaining lower vibration levels below 2.5 m/s², depending on orbit radius and operation speed.

Implementation Method 1

an eccentric sleeve (15) coupling the drive shaft (12) to the retainer bearing (14), to convert the rotational force of the motor into an orbital movement of the platen (16)

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the tool (10) includes a counterweight (18) coupled to the drive shaft (12)... Positioning of the counterweight (18) in this manner may counteract imbalance and reduce vibration when the motor is rotating the drive shaft (12)

Methodology Applied
Scientific EffectCounterweight balancing:

Implementation Method 3

vibration of the tool (10) may increase due to additional external forces introduced by resistance between the finishing surface of the workpiece and the sandpaper

Methodology Applied
Scientific EffectFriction resistance: Friction

Data Source

PatentEP3023197B1Power tool with counterweight arrangement
Publication Date: 2022.03.30 BLACK & DECKER CORP
  • EP3023197B1 patent drawingFigure 1A
  • EP3023197B1 patent drawingFigure 1B
  • EP3023197B1 patent drawingFigure 2A

AI summary

A power tool may include a motor and a drive shaft having a first end coupled to the motor and a second end eccentrically coupled to a platen by a retainer bearing and eccentric sleeve. A counterweight component may be coupled to the second end of the drive shaft to counteract imbalance generated by rotation of the retainer bearing, eccentric sleeve and platen. The counterweight component may include a counterweight coupled to the second end of the drive shaft, between the eccentric sleeve and the platen. Alignment of the counterweight may be offset with respect to a centerline of the drive shaft to counteract vibration generated due to interaction of the platen with a workpiece. The counterweight component may also include a counterweight mass member coupled to a sector of the counterweight to counteract vibration generated due to interaction of the platen with a workpiece.