Adjustable Stop Lever Switch-Off for Crane Rope

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Solution Overview

Problem

Existing crane arrangements with switch-off devices are prone to unintentional or premature shutdown due to dirt or incorrect cable usage, and electronic solutions like RFID are sensitive and prone to damage or malfunction.

Innovation Solution

A mechanical switch-off device with adjustable stop levers forms a passage for the crane cable, allowing easy adjustment to accommodate different cables and termination elements, featuring rod-shaped stop levers mounted on crossbars with adjustable guides and locking positions, ensuring reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed stop lever is used in the switch-off device, then the structure is simple, but it cannot accommodate different crane cables or termination elements

Engineering Contradiction:

Improveadaptability to different crane cablesVSAvoidcomplexity of stop lever arrangement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The stop levers are made adjustable in position along the crane cable, allowing them to be dynamically repositioned to accommodate different cable diameters and termination elements. This dynamic adaptability resolves the contradiction by enabling the device to work with various cable configurations without requiring a completely different fixed structure for each type.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The distance between the two stop levers can be changed by adjusting their individual positions along the crane cable. This parameter change allows the passage width to be modified to match different cable sizes, providing versatility while maintaining a relatively simple overall device structure.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If electronic sensors like RFID are used for the shutdown device, then the measurement precision is high, but the reliability decreases due to sensitivity to dirt, damage, and displacement

Engineering Contradiction:

Improvereliability of shutdown deviceVSAvoidsensitivity to dirt and damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces electronic sensors (RFID readers and tags) with a purely mechanical switch-off device using stop levers and a crane cable-based mechanism. This mechanical system is inherently more reliable in outdoor construction environments because it has no electronic components that can be damaged by dirt, water, or physical impact, directly resolving the reliability issue while maintaining shutdown functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The mechanical switch-off device uses the crane cable itself as part of the triggering mechanism. When the crane cable is pulled taut or the termination element contacts the stop lever, the mechanism automatically activates the shutdown function without requiring external electronic sensing systems that are vulnerable to environmental factors.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If the stop lever is positioned close to the deflection pulley, then the shutdown function is sensitive, but unintentional shutdowns occur due to dirt or cable thickness

Engineering Contradiction:

Improveprecision of shutdown triggerVSAvoidunintentional shutdown prevention

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The switch-off function is divided into two separate stop levers positioned at different locations along the crane cable. The first stop lever provides initial sensitivity near the deflection pulley, while the second stop lever provides a backup trigger point further along the cable. This segmentation allows the system to maintain sensitivity while reducing false triggers by requiring either lever to be activated, not just one.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The adjustable passage between the two stop levers creates a buffer zone that accommodates variations in cable thickness and positioning. This passage acts as a cushioning mechanism that prevents unintentional activation while still allowing the shutdown function to trigger reliably when the crane cable reaches its intended end position.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3395745B1Crane arrangement

Publication Date: 2019.09.18 BAUER MASCH GMBH

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AI summary

The invention relates to a crane arrangement with a mast (12) or crane boom on which at least one deflection pulley (16) is arranged, over which at least one crane rope (20) is guided substantially vertically downwards, wherein the crane rope has a termination element at its free end, a winch for actuating the crane rope and a shut-off device (30) for switching off the winch when the termination element of the crane rope approaches the deflection pulley, wherein the shut-off device has a stop lever (32) by which the shutdown can be effected upon contact with the termination element.According to the invention, the shut-off device has at least one first stop lever (32a) and one second stop lever (32b) which are spaced apart from each other forming a passage (34), the first stop lever and the second stop lever are adjustable to change the passage, and the crane rope is guided through the adjustable passage.