Hoist Chain Guide Rotation Sensing for Jam Shutdown

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Solution Overview

Problem

Existing hoists in the entertainment industry suffer from chain jams due to excessive load chain piling, leading to damage and unintended clutch activation, especially when operated in an inverted configuration without proper orientation, and there is a need for a safeguard to prevent power shutdown before a predetermined torque level is reached.

Innovation Solution

A torque limiting device is integrated into a chain guide subsystem of a hoist, featuring a chain detangler, a biasing member, and a sensor to detect rotation and shut off power when a predetermined torque is exceeded, preventing damage and ensuring safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the hoist is operated in inverted configuration with excessive load chain piled on the unit, then the chain cannot untwist properly, but this causes chain knots and overload clutch activation leading to damage

Engineering Contradiction:

Improveinverted configuration operationVSAvoidchain untwisting function

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The sensor detects chain misalignment before a knot fully forms and activates the shutdown sequence in advance, preventing the harmful condition of chain knots and clutch damage from occurring

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sensor provides continuous feedback on chain alignment status, and the control system adjusts power delivery based on this feedback to maintain safe operation or shut down when misalignment is detected

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If the overload clutch is allowed to slip for extended periods to handle chain knots, then the clutch continues to slip until operator return, but this extended slip causes damage to the hoist frame and detangler

Engineering Contradiction:

Improveclutch slip toleranceVSAvoidhoist frame integrity

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The sensor detects chain misalignment before excessive clutch slip occurs and triggers an immediate shutdown sequence, preventing the harmful extended slip condition from developing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sensor provides real-time feedback on chain alignment, enabling the control system to shut down power before the clutch slip reaches damage-causing levels

Inventive Principle:

Principle #23Feedback

3Reliability

If a safeguard shuts down the unit when predetermined force is exerted on entry/exit ports, then chain jam damage is prevented, but the system shuts off power before a predetermined torque level is reached

Engineering Contradiction:

Improvechain jam preventionVSAvoidpower shutdown timing

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The sensor measures chain alignment parameters and the control system adjusts the shutdown threshold to activate only when actual chain misalignment is detected, rather than shutting down at fixed torque levels, maintaining both safety and productivity

Inventive Principle:

Principle #35Parameter changes

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 device effectively prevents chain jams and damage by shutting off power when excessive torque is detected, thereby protecting the hoist from unnecessary wear and ensuring safe operation.

Implementation Method 1

A biasing member (74) is supported by the hoist frame (10)... The biasing member (74) engages with the chain guide subsystem (37) to provide a rotational torque limiting device

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

A sensor (87) is configured to detect rotation of the chain guide subsystem (37) relative to the hoist frame (10)

Methodology Applied

Scientific EffectPosition detection:

Implementation Method 3

A chain detangler (92) is mounted on the chain guide subsystem (37) and is configured to guide the chain (49) into and out of the chain guide subsystem (37)

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP4711320A1Chain jam detection device

Publication Date: 2026.03.18 COLUMBUS MCKINNON CORP

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AI summary

A chain jam detection device for use with a hoist (6) having a chain (49). The chain jam detection device includes a hoist frame (10) with a chain guide subsystem (37) pivotally mounted on the hoist frame (10). The chain guide subsystem (37) has a housing (52) enclosing a lift wheel (40) for conveying the chain (49). The lift wheel (40) is configured to rotate about a lift wheel axis (109). A chain detangler (92) mounted on the chain guide subsystem (37) is configured to guide the chain (49) into and out of the chain guide subsystem (37). A biasing member (74) is supported by the hoist frame (10). The device is configured such that force of the chain (49) against the chain detangler (92) when a chain link is misaligned causes the chain guide subsystem (37) to rotate relative to the hoist frame (10). A sensor (87) is configured to detect rotation of the chain guide subsystem (37) relative to the hoist frame (10). The biasing member (74) engages with the chain guide subsystem (37) to provide a rotational torque limiting device, and the sensor (87) causes power to the hoist (6) to be shut off when a predetermined threshold for torque is exceeded.