Safety Catch for Storage and Retrieval Device

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing safety devices for storage and retrieval devices often respond with a delay, leading to potential damage and risk to personnel or equipment during hoist failures, as they rely on detecting excessive speed rather than impending crashes, and are limited in detecting suspension element damage.

Innovation Solution

A safety device with a monitoring system using force measuring sensors to detect tension changes in suspension elements, coupled with an energy storage and control mechanism to activate a holding device for early intervention and braking, allowing for prompt interception of the lift truck before significant kinetic energy is built up.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If safety devices rely on detecting excessive speed to activate braking, then the braking system can be activated, but the response is delayed and kinetic energy is already built up, leading to potential damage

Engineering Contradiction:
Improvesafety response reliabilityVSAvoidbraking response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The monitoring device continuously monitors suspension element tension during normal operation to detect early signs of failure (such as gradual tension loss or abnormal variations) before a crash occurs. This preliminary detection allows the control device to activate the holding device in advance, preventing the build-up of kinetic energy and eliminating the delay inherent in speed-based detection systems.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If safety devices use speed sensors to detect crashes, then braking can be activated, but the system cannot detect suspension element damage before it causes a crash

Engineering Contradiction:
Improvecrash detection capabilityVSAvoidsuspension element damage detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The monitoring device acts as an intermediary between the suspension elements and the control system. Instead of directly monitoring speed or crash conditions, it monitors the tension in suspension elements as an intermediate parameter that reflects their structural integrity. This allows early detection of suspension element damage through tension variations, enabling preventive action before a crash occurs.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the holding device is activated early based on tension monitoring, then kinetic energy is reduced and damage is minimized, but the system complexity increases with additional sensors and control mechanisms

Engineering Contradiction:
Improveconsequential damageVSAvoidsafety device structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The monitoring device serves multiple functions: it continuously monitors suspension element tension during normal operation, detects early signs of failure, and triggers the holding device when necessary. By integrating these functions into a single monitoring system, the patent avoids the need for separate detection systems for different failure modes, thereby limiting the increase in overall system complexity while achieving early intervention.

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

Enables early detection and prevention of crashes, reducing the risk of damage and injury by intercepting the lift truck at lower speeds, and providing enhanced detection capabilities for suspension element issues, thereby minimizing consequential damage.

Implementation Method 1

The monitoring device has at least one force measuring sensor, which is designed to detect a tension in the traction means

Methodology Applied
Scientific EffectForce measurement: Force

Data Source

PatentEP3044155B1Safety apparatus for a storage and retrieval device, storage and retrieval device and method for monitoring a storage and retrieval device
Publication Date: 2017.07.05 SSI SCHAEFER AUTOMATION GMBH (DE)
  • EP3044155B1 patent drawingFigure 1
  • EP3044155B1 patent drawingFigure 2
  • EP3044155B1 patent drawingFigure 3

AI summary

Safety apparatus (80), in particular a safety catch, for a storage and retrieval device (10), a storage and retrieval device (10) comprising lifting gear (30) for driving a moveable lift truck (38) which is coupled to at least one supporting means (60), and a method for monitoring a storage and retrieval device (10). The safety apparatus (80) has a monitoring device (84) which is designed to detect a load state of the at least one supporting means (60), in particular a measured variable that is dependent on the supporting means tension, a holding device (90), in particular a safety catch, which is designed to inhibit a movement of the lift truck (38) selectively, an energy storage device (96), which is designed to supply energy to the holding device (90), and a control device (82), which is designed to actuate the energy storage device (96) depending on a signal detected by the monitoring device (84) in order to activate the holding device (90).