Centrifugal Clutch Layout With Internal Weights for Compact Engagement

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Solution Overview

Problem

Existing clutch mechanisms require user input for engagement and disengagement, lacking simplicity, cost-effectiveness, and space-efficiency.

Innovation Solution

A centrifugal clutch mechanism with a disk and centrifugal weights that automatically transition between disengaged and engaged positions based on rotational speed, using centrifugal force to interface with drive surfaces for power transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If user engageable elements (clutch fork) are used for engagement, then the clutch mechanism can be controlled, but the operation becomes complex and requires user input

Engineering Contradiction:
Improveoperation simplicityVSAvoidclutch mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The clutch mechanism automatically engages and disengages based on rotational speed without requiring user input. The centrifugal weights self-actuate to control the friction element engagement with the drive shaft, making the system self-regulating and eliminating the need for manual clutch forks or engagement mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces traditional mechanical clutch engagement mechanisms (clutch forks, levers) with a centrifugal force-based automatic engagement system. The mechanical system uses rotational speed-dependent centrifugal force to automatically control engagement, substituting complex manual mechanical control with a simpler physics-based automatic system.

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

2Reliability

If traditional meshing interfaces are used, then power transmission is reliable, but the mechanism occupies more space

Engineering Contradiction:
Improvepower transmission reliabilityVSAvoidclutch mechanism volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The clutch mechanism transitions from a static engagement system to a dynamic one where the friction element's position and engagement state change continuously with rotational speed. The centrifugal weights dynamically adjust the friction element's radial position, enabling automatic engagement/disengagement based on operating conditions while maintaining compact dimensions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The friction element and centrifugal weights are positioned within the housing such that they nest within the available space when disengaged. The friction element can radially extend to engage the drive shaft while remaining contained within the housing boundaries, maximizing space utilization and maintaining a compact overall mechanism volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Extent of automation

If centrifugal weights are used for automatic engagement, then user input is eliminated, but the mechanism requires higher rotational speed for engagement

Engineering Contradiction:
Improveengagement automationVSAvoidrotational speed requirement
Core Design Contradiction:
Extent of automationVSSpeed

Solution Approach 1:

The patent adjusts the centrifugal force parameters by modifying the mass and radial position of the weights, and the spring constant of the biasing spring to achieve engagement at lower rotational speeds. By changing these physical parameters, the system maintains automatic engagement capability while reducing the minimum speed threshold required for clutch activation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The biasing spring pre-compresses the friction element against the drive shaft at low speeds, maintaining initial engagement pressure. As rotational speed increases, centrifugal force progressively overcomes the spring pressure to modulate the engagement level, allowing the system to begin power transmission at lower speeds and progressively increase engagement as speed rises.

Inventive Principle:
Principle #10Preliminary action

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

Provides automatic, efficient, and space-saving power transmission without requiring user input, optimizing clutch operation.

Implementation Method 1

the centrifugal weights rotate between a disengaged position in which the centrifugal weights do not interface with drive surfaces and an engaged position in which the centrifugal weights interface with the drive surfaces

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4279761B1Clutch mechanism
Publication Date: 2025.09.03 MILWAUKEE ELECTRIC TOOL CORP
  • EP4279761B1 patent drawingFigure 1~2
  • EP4279761B1 patent drawingFigure 3~4
  • EP4279761B1 patent drawingFigure 5~6

AI summary

A clutch (132) includes an input (128); an output (130); a centrifugal clutch mechanism that transfers energy from the input to the output, the centrifugal clutch mechanism including: a disk (134); centrifugal weights (142A) movably coupled to the disk; and a central shaft (162) rotatable relative to the disk (134) and extending through the disk, the central shaft comprising drive surfaces (164), wherein the disk is rotatably coupled to the input, wherein the output is rotatably coupled to the central shaft, wherein the centrifugal weights rotate between a disengaged position in which the centrifugal weights do not interface with drive surfaces and an engaged position in which the centrifugal weights interface with the drive surfaces, and wherein the centrifugal weights are disposed inside the perimeter of the disk when the centrifugal weights are in the engaged position.