Cable Wrap Clutch Torque Limiter Shutoff

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Solution Overview

Problem

Conventional wrap spring clutches experience significant frictional heat and wear during engagement and disengagement, leading to degradation over time, and often require substantial forces for disengagement, which can be a challenge in applications with insufficient mass or low speeds.

Innovation Solution

A rotational coupling device utilizing a cable instead of a spring to transmit torque between input and output hubs, along with a torque limiter that includes an electromagnet and armature plate for controlled disengagement, reduces friction and engagement forces, and allows for torque limiting under excessive loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a wrap spring is used to transmit torque between hubs, then torque transmission is achieved, but frictional heat and wear increase during engagement and disengagement

Engineering Contradiction:

Improvetorque transmissionVSAvoidfrictional heat and wear

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the traditional wrap spring mechanism with a cable-based system. The cable is wrapped around the hubs and tensions to transmit torque, eliminating the need for a wrap spring that generates frictional heat and wear during engagement and disengagement. This substitution maintains torque transmission capability while removing the harmful frictional effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameters of the coupling mechanism by using a cable with specific tension characteristics instead of a compressible spring. The cable system operates under tension rather than compression, fundamentally changing the mechanical parameters of the system to reduce friction and wear during operation.

Inventive Principle:

Principle #35Parameter changes

2Power

If a wrap spring is used for clutch engagement, then torque coupling is achieved, but disengagement forces become substantial

Engineering Contradiction:

Improvetorque couplingVSAvoiddisengagement forces

Core Design Contradiction:

PowerVSForce

Solution Approach 1:

The patent substitutes the wrap spring system with a cable system that uses tension to engage and controlled release mechanisms to disengage. The cable can be easily released by reducing tension, eliminating the substantial disengagement forces required by spring-based systems that must overcome spring compression forces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the disengagement function from the cable itself by incorporating a separate release mechanism. The cable remains in place but can be quickly released by actuating the release mechanism, separating the engagement function (cable tension) from the disengagement function (release mechanism activation).

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If a common structure is used for disengagement and torque limiting, then device complexity is reduced, but control precision may be compromised

Engineering Contradiction:

Improvestructure complexityVSAvoidtorque control precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent designs a release mechanism that serves dual functions: it can disengage the clutch by releasing cable tension and can also limit torque by preventing excessive cable tension. This multi-functional design reduces device complexity while maintaining adequate control through a single integrated mechanism.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 cable-based design minimizes frictional heat and wear, enabling smoother engagement and disengagement with reduced forces, and the torque limiter effectively manages excessive loads to prevent damage and extend clutch life.

Implementation Method 1

The cable reduces engagement forces and minimizes slip between the cable and hubs

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

The electromagnet is configured, when energized, to attract the armature plate and torque transmission plate in a second axial direction away from the attachment ring

Methodology Applied

Scientific EffectElectromagnet: Electromagnet

Data Source

PatentUS10066680B2Cable wrap clutch with torque limiter shutoff and operator controlled re-engagement

Publication Date: 2018.09.04 INERTIA DYNAMICS INC

AI summary

A rotational coupling includes input and output hubs disposed about a rotational axis and an attachment ring disposed about the axis on one side of the input hub opposite the output hub. A flexible, multi-coil body such as a cable is disposed radially outwardly of the input and output hubs and couples the hubs together for rotation upon rotation of the input hub in one rotational direction. The body has ends coupled to the output hub and attachment ring. A torque limiter includes a torque transmission plate configured to rotate with the input hub and an armature plate fixed against rotation. The torque transmission plate and armature plate are configured to move axially together along the axis of rotation. An electromagnet disposed on one side of the torque limiter opposite the input hub attracts the plates in a second axial direction away from the attachment ring when energized.