Indexed Winch Locking for Precise Cable Tension Retention

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Solution Overview

Problem

Existing winches for roof edge safety systems lack reliable and precise tensioning mechanisms, prone to accidental release and slippage, and fail to maintain consistent cable tension due to single-point locking and friction-based systems.

Innovation Solution

A winch design with multiple pawls and indexing locks, combined with offset locking pin holes, provides redundant retention and precise tensioning, using a separate drive coupler for torque wrench adjustment, minimizing mechanical failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-point locking mechanism is used in the winch, then the device complexity is reduced, but the reliability of cable tension maintenance deteriorates due to accidental release and slippage

Engineering Contradiction:

Improvewinch structureVSAvoidcable tension maintenance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The winch locking mechanism is segmented into multiple independent components: a primary pawl-ratchet system for main locking, a secondary indexing pin with multiple holes for precise positioning, and a third retaining mechanism. This segmentation distributes the reliability function across multiple independent elements, so that failure of one does not compromise the entire system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design incorporates redundant locking elements that act as pre-prepared backup systems. The indexing pin with multiple holes provides pre-positioned locking points, and the secondary pawl provides a backup locking path, cushioning against the harmful effect of accidental release or slippage in the primary mechanism.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If a friction-based tensioning system is used, then the ease of operation is improved, but the manufacturing precision of cable tension deteriorates due to inconsistent tension levels

Engineering Contradiction:

Improvetensioning operationVSAvoidcable tension precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The system replaces pure friction-based tensioning with a positive mechanical locking system using the indexing pin and ratchet mechanism. The indexing pin engages with specific holes at predetermined positions, providing precise, repeatable tension levels without relying on friction coefficients, thereby achieving both ease of operation and manufacturing precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The design changes the tensioning parameter control from continuous friction adjustment to discrete indexed positions. The multiple holes in the indexing pin create distinct, predetermined tension levels, transforming the continuous friction parameter into discrete, precisely controllable steps.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple pawls and indexing locks are added to the winch, then the reliability of cable tension maintenance is improved, but the device complexity increases

Engineering Contradiction:

Improvecable tension maintenanceVSAvoidwinch structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple locking functions are merged into a single integrated indexing pin assembly that combines the positioning pin, multiple indexing holes, and retention features. This merging reduces the number of separate components and assembly steps, thereby limiting the increase in device complexity while maintaining enhanced reliability through redundant locking mechanisms.

Inventive Principle:

Principle #5Merging (Combining)

4Manufacturing precision

If a separate drive coupler with torque wrench adjustment is used, then the manufacturing precision of cable tension is improved, but the ease of operation deteriorates due to additional adjustment steps

Engineering Contradiction:

Improvecable tension precisionVSAvoidtensioning operation

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The drive coupler with torque wrench adjustment enables the operator to self-regulate and precisely control the tensioning force applied to the cable. The torque wrench provides immediate feedback and control, allowing the operator to achieve precise tension levels without requiring external equipment or complex adjustment procedures, thereby maintaining ease of operation while improving manufacturing precision.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12576292B1Winch

Publication Date: 2026.03.17 SCEPANIAK IP HOLDINGS LLC

AI summary

A winch has a cable reel, a winch body capturing the cable reel, and an indexing lock. Two separately actuated pawls provide a first level of fail-safe protection. A drive coupler enables rapid torque wrench cable tension adjustment. Locking pin holes on the cable reel and winch body are arranged so a locking member can pass through only one visible winch body locking pin hole, with the other visible holes at least partially blocked, independent of pawl position. The locking pin provides a second level fail safe. As the cable reel is rotated by the drive coupler, even by a small amount less than required for a single pawl ratchet tooth displacement, another visible winch body locking pin hole will align and open. As a result, very precise cable tension and reel position can be preserved by insertion of the locking pin into the only open locking pin hole.