Crane Cable Tensioning Device for Rope Breakage Safety
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Solution Overview
Problem
Conventional mechanical, gravity-actuated rope breakage safety devices in cranes are unreliable, especially in luffing jibs with steep positions, and are not suitable for mobile fast-erecting cranes due to weight and space constraints, as they fail to ensure safe operation when trolley cables break.
Innovation Solution
A cable tensioning device that applies a test tensile force to the trolley cable before crane operation, detect damaged ropes, and functions as a dual-mode system for both testing and regular operation, allowing for early detection of damaged cables without additional weight or space, using a control device to switch between test and operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical gravity-actuated rope breakage safety device is installed, then safety against rope breakage is improved, but weight and space requirements increase significantly
Solution Approach 1:
The patent replaces the mechanical gravity-actuated safety device with an active testing system using a cable tensioning device and control unit. Instead of relying on mechanical form-fit engagement triggered by gravity, the system actively measures cable tension forces and compares them against threshold values to detect cable failures, substituting mechanical safety mechanisms with sensor-based detection.
Solution Approach 2:
The cable tensioning device serves dual purposes: it performs both the regular tensioning function during crane operation and the safety testing function. The same actuator and sensor system used for normal cable tensioning is utilized to apply test loads and monitor cable strength, eliminating the need for separate dedicated safety devices.
2Reliability
If a mechanical gravity-actuated rope breakage safety device is installed, then safety against rope breakage is improved, but space requirements increase
Solution Approach 1:
The cable tensioning device is designed to perform multiple functions: regular cable tensioning during crane operation and safety testing by applying test loads. The control unit switches between operational mode and testing mode, allowing the same physical components to serve both purposes, thereby eliminating the need for separate space-consuming safety devices.
Solution Approach 2:
The patent merges the safety testing function with the existing cable tensioning system. The actuator, cable tensioning device, and control unit are combined into a single integrated system that performs both operational tensioning and safety verification, consolidating functions that would traditionally require separate mechanical safety devices.
3Weight of stationary object
If the cable tensioning device is used in dual mode for testing and operation, then additional weight and space are avoided, but device complexity increases
Solution Approach 1:
The control unit dynamically switches between operational mode and testing mode based on operational requirements. The system adapts its behavior by adjusting the cable tensioning force: applying normal operational tension during crane operation and applying elevated test loads during safety verification, with the control unit managing the transition between these different operational states.
Solution Approach 2:
The system changes the tension force parameter to distinguish between operational and testing modes. During normal operation, the cable tensioning force remains within standard operational limits, while during safety testing, the control unit increases the tension force to elevated test levels to verify cable strength, using parameter variation to achieve multiple functions.
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
Ensures safe operation by identifying and discarding damaged cables before regular operation, preventing accidents and optimizing space and weight by integrating the testing function into the existing cable tensioning system, ensuring reliable detection of trolley cable strength, especially in luffing booms.
Implementation Method 1
a rope condition check should be carried out in the form of a tensile force load on the rope drive
Implementation Method 2
A cable tensioning device applies a test tensile force to the trolley cable before crane operation
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a crane [1], in particular in the form of a mobile fast-erecting crane, comprising cabling and a testing device for testing at least one cable [6] of the cabling for sufficient strength, and to a method for testing the cabling of such a crane, wherein a testing tensile force is applied to at least one cable, in particular the trolley cable. According to the invention, a testing tensile force is applied to the cable [6] by a cable tensioning device [7], which is operated in a testing mode when the cable is installed on the crane [1] but before the crane operation is enabled.