Hoist Chain Guide Torque Shutdown for Jam Prevention
Find Innovative SolutionsGenerate Solutions
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 the 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
Engineering Contradiction Analysis
1Reliability
If the hoist is operated in inverted configuration with excessive load chain piled on the unit, then the chain detangler feature works to untwist the load chain, but the excessive chain prevents the chain from being able to untwist, causing a knot to be pulled into the hoist and activating the overload clutch
Solution Approach 1:
The patent applies preliminary action by detecting chain misalignment before a knot fully forms and pulls into the hoist. The sensor detects rotation of the chain guide subsystem caused by chain force against the detangler, triggering power shutdown before the overload clutch is activated, preventing chain knot formation and hoist damage
Solution Approach 2:
The patent implements feedback through a sensor that continuously monitors the rotational position of the chain guide subsystem. When the sensor detects rotation indicating chain misalignment, it triggers a feedback loop that shuts off power to the hoist motor, preventing further chain accumulation and potential knot formation
2Strength
If the overload clutch is allowed to slip for extended periods to prevent immediate damage, then the clutch continues to slip until the operator returns, but this extended clutch slip results in damage to the hoist frames and detangler
Solution Approach 1:
The patent applies preliminary action by shutting off power at the first sign of chain misalignment through sensor detection, preventing the condition from progressing to overload clutch activation. This early intervention eliminates the need for extended clutch slipping and prevents subsequent damage to hoist frames and detangler
Solution Approach 2:
The patent implements feedback by continuously monitoring chain guide subsystem rotation and immediately shutting off power when misalignment is detected. This feedback mechanism prevents the overload clutch from activating in the first place, eliminating extended clutch slip and protecting hoist frame integrity
3Reliability
If a safeguard is provided to shut down the unit when a predetermined force is exerted on the entry/exit ports, then the unit shuts down to prevent damage, but the power is shut off before a predetermined torque level is reached
Solution Approach 1:
The patent uses the chain guide subsystem rotation as an intermediary indicator of chain misalignment. Instead of directly measuring force or torque at the entry/exit ports, the sensor detects rotation of the chain guide subsystem, which serves as a reliable proxy for chain misalignment conditions, enabling accurate detection without direct torque measurement
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 safeguarding 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
Implementation Method 2
the sensor (87) comprises a load cell with a strain gauge
Data Source
AI summary
A chain jam detection device for use with a hoist having a chain. The chain jam detection device includes a hoist frame with a chain guide subsystem pivotally mounted on the hoist frame. The chain guide subsystem has a housing enclosing a lift wheel for conveying the chain. The lift wheel is configured to rotate about a lift wheel axis. A chain detangler mounted on the chain guide subsystem is configured to guide the chain into and out of the chain guide subsystem. A biasing member is supported by the hoist frame. The device is configured such that force of the chain against the chain detangler when a chain link is misaligned causes the chain guide subsystem to rotate relative to the hoist frame. A sensor is configured to detect rotation of the chain guide subsystem relative to the hoist frame. The biasing member engages with the chain guide subsystem to provide a rotational torque limiting device, and the sensor causes power to the hoist to be shut off when a predetermined threshold for torque is exceeded.