Winch Clutch Torque Adjustment via Drum Radius Feedback

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Solution Overview

Problem

Traditional winch clutches have a fixed torque setting, which can lead to slipping and payload drop due to increasing torque requirements as the winch cable winds up, as the effective drum radius increases, causing moment effects that exceed the clutch's friction-based maximum torque.

Innovation Solution

A clutch system that adjusts torque setting by varying the biasing force through axial displacement of a plunger, using disc springs or other biasing members, in response to changes in the effective drum radius, ensuring the clutch slips before harmful loads are transmitted, and maintaining appropriate torque for the load and radius during winding and unwinding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed torque setting is used in the clutch, then the structure is simple and easy to manufacture, but the clutch slips when torque increases due to drum radius variation, causing payload drop

Engineering Contradiction:
Improveclutch engagement reliabilityVSAvoidclutch adjustment mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The clutch biasing force is made dynamic rather than fixed. A plunger mechanism axially displaces in response to drum radius changes, automatically adjusting the spring compression and thus the clutch torque setting. This dynamic adjustment ensures the clutch maintains reliable engagement across varying operating conditions without requiring complex external control systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The clutch system self-adjusts its torque setting through the plunger's automatic response to drum radius variation. The mechanism uses the mechanical connection between the drum, plunger, and spring pack to automatically vary the biasing force, eliminating the need for external actuators or complex control systems while maintaining reliability.

Inventive Principle:
Principle #25Self-service

2Reliability

If the clutch torque setting is increased to prevent slipping during high torque conditions, then the clutch remains engaged, but the structure to which the winch is attached may be damaged by harmful loads

Engineering Contradiction:
Improveclutch engagement reliabilityVSAvoidharmful loads transmitted to structure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The clutch torque setting dynamically adapts to the current drum radius and load conditions. When the drum radius increases and torque requirements rise, the plunger axially displaces to increase spring compression, raising the clutch torque threshold. This ensures the clutch remains engaged under normal high-torque conditions while still slipping before harmful loads can damage the attached structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The clutch torque parameter is changed in response to drum radius variation. The mechanical linkage causes the spring compression (and thus torque setting) to vary as the drum radius changes, allowing the clutch to maintain appropriate engagement levels across different operating conditions without transmitting harmful loads to the structure.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If the effective drum radius increases during cable winding, then the cable capacity increases, but the torque requirement increases causing clutch slip

Engineering Contradiction:
Improvecable capacity on drumVSAvoidtorque requirement
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The clutch torque setting dynamically increases as the drum radius increases during cable winding. The plunger mechanism converts the radial growth of the drum into axial displacement that compresses the spring pack, automatically raising the clutch torque threshold to match the increasing torque requirements, thereby preventing clutch slip while allowing continued cable accumulation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates mechanical feedback from the drum radius variation to the clutch torque setting. As the drum radius increases, the plunger is axially displaced, which increases spring compression and thus the clutch torque setting. This feedback loop ensures the clutch torque setting automatically tracks the torque requirements imposed by the increasing drum radius.

Inventive Principle:
Principle #23Feedback

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 adjustable clutch system prevents premature slipping during increased torque conditions and ensures safe load handling by dynamically adjusting the torque setting based on the effective drum radius, maintaining clutch engagement and preventing payload drops.

Implementation Method 1

the biasing member comprises one or more disc springs positioned around the output shaft

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

the frictional engagement of the input and output friction plates varies, and as such, the torque setting at which the plates slip relative to each other also varies

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3095747B1Winch or hoist system with clutch adjustment
Publication Date: 2018.09.26 GOODRICH CORP
  • EP3095747B1 patent drawingFigure 1
  • EP3095747B1 patent drawingFigure 2
  • EP3095747B1 patent drawingFigure 3

AI summary

A clutch (5; 105; 205) comprises an input shaft (110; 210), an output shaft (112; 212), a biasing member (128; 228) and a plunger (116; 216). The biasing member (128; 228) is arranged to provide a biasing force that allows torque transfer from the input shaft (110; 210) to the output shaft (112; 212) via one or more input friction plates (120; 220) and one or more output friction plates (130; 230). Axial displacement of the plunger (116; 216) relative to the output shaft (112; 212) may cause the biasing force to vary to adjust the maximum torque setting of the clutch (5; 105; 205) during reeling-in or reeling-out of a winch cable (7a) around a winch drum (7). A winch assembly may be provided that includes an arm (10) in operable connection with a winch drum (7). The arm (10) is displaced as the effective radius of the drum (7) varies during reeling in or reeling out. Displacement of the arm (10) can be communicated to the plunger (116; 216) to provide the axial displacement thereof.