Cam-Adjusted Orbital Stroke for Paint Defect Removal Control

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Solution Overview

Problem

Current random orbital machines lack an adjustable stroke mechanism that allows users to customize the orbital path without special tools or disassembly, limiting their versatility and effectiveness in addressing varying paint defects and surface areas.

Innovation Solution

An adjustable stroke device with a housing, counterweight, mounting assembly, and cam mechanism that allows variable adjustment of the stroke radius through an adjuster ring and detent system, enabling seamless transition between rotary and dual-action modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the stroke length is fixed in small stroke machines (6mm-12mm), then the machine is easier to control with smoother action, but the machine cannot effectively cut into paint to remove surface defects

Engineering Contradiction:
Improveease of controlVSAvoidability to remove surface defects
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements an adjustable stroke mechanism that allows the stroke length to be dynamically changed by the user. The adjustable stroke device includes a mechanism that can vary the offset distance between the driveshaft axis and the backing plate rotational axis, enabling transition from small stroke (6mm-12mm) to large stroke configurations. This dynamic adjustment resolves the contradiction by allowing users to select small stroke for smooth polishing actions and large stroke for aggressive cutting actions to remove surface defects.

Inventive Principle:
Principle #15Dynamics

2Speed

If the RPM is increased to compensate for small stroke limitations, then the rotation speed increases, but the motor experiences more strain and reduced longevity

Engineering Contradiction:
Improverotation speedVSAvoidmotor longevity
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

Instead of increasing RPM to achieve larger effective stroke, the patent changes the stroke length parameter directly through the adjustable stroke device. By increasing the offset distance between the driveshaft and backing plate axes, the pad travels a larger orbital path at the same RPM. This resolves the contradiction by achieving the desired cutting action through increased stroke length rather than increased speed, thereby maintaining motor longevity while still enabling effective paint defect removal.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If an adjustable stroke mechanism is added to random orbital machines, then the versatility and customization capability improve, but the device complexity increases

Engineering Contradiction:
Improvecustomization capabilityVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The adjustable stroke device is nested within the existing housing of the random orbital machine. The mechanism integrates with the existing drivetrain and mounting assembly, with the counterweight and cam mechanism fitting within the available internal space. This nesting approach allows the addition of adjustable stroke functionality without requiring a complete redesign of the machine architecture, thereby limiting the increase in overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent introduces a cam mechanism as an intermediary element that translates rotational motion into the desired linear adjustment of the offset distance. The cam profile, when rotated, moves the mounting assembly and backing plate to different positions relative to the driveshaft, thereby adjusting the stroke length. This intermediary mechanism provides a simple and effective way to achieve stroke adjustment without complex control systems or multiple components.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If a large stroke machine is used to increase orbits per minute and cutting action, then more surface area is treated and defects are removed, but the machine produces more vibrations and is harder to control

Engineering Contradiction:
Improvesurface area treatmentVSAvoidcontrol stability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The adjustable stroke mechanism allows users to dynamically select between small stroke and large stroke modes based on the specific task requirements. For detailed polishing work requiring stability and precision, users can select small stroke settings that provide smoother action and easier control. For rapid stock removal and large surface area treatment, users can switch to large stroke settings that increase orbits per minute and cutting action. This dynamic adaptability resolves the contradiction by allowing optimal performance characteristics to be selected for each specific application.

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

Enables users to customize the orbital path and movement of the pad, enhancing control and efficiency in paint correction and surface treatment without risking swirl marks or motor strain, thus improving user experience and tool longevity.

Implementation Method 1

The stroke adjuster includes an adjuster ring and a cam mechanism secured to the adjuster ring. The counterweight engages the cam mechanism which moves the counterweight in response to cam movement.

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP4088862B1Adjustable stroke device with cam
Publication Date: 2024.12.04 LAKE COUNTRY TOOL LLC
  • EP4088862B1 patent drawingFigure 1
  • EP4088862B1 patent drawingFigure 2
  • EP4088862B1 patent drawingFigure 3

AI summary

An adjustable stroke device for a random orbital machine has a housing with a central axis and a wall defining a cavity. At least one counterweight is movably disposed at least partially within the cavity. A mounting assembly is disposed at least partially within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjuster couples the at least one counterweight with the mounting assembly. The stroke adjuster enables the at least one counterweight and mounting assembly to move with respect to one another such that a distance between the at least one counterweight and the mounting assembly may be variably adjusted which, in turn, variably adjust a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing. The stroke adjuster has an adjuster ring and a cam mechanism secured with the adjuster ring.