Rope Test Stand With Dual Drives For Variable Load Simulation

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Solution Overview

Problem

Current rope test benches inadequately simulate the load cycles and spool retention of ropes used in crane and hoist applications, failing to accurately determine service life and permissible bending cycles due to limited simulation of real-world load variations and spooling behaviors.

Innovation Solution

A rope test stand with two cable drives allows for varying the load on the test rope during different phases of the test cycle without changing the test load, simulating realistic load changes and spool retention by activating an additional rope drive to adjust the tension, and using a safety rope to secure the test load and assist in lifting and lowering processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single rope drive is used to wind and unwind the test rope, then the device complexity is low, but the ability to simulate realistic load cycles and spool retention is insufficient

Engineering Contradiction:
Improvesimulation capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rope drive system is segmented into two independent drives: a first rope drive for winding the test rope onto the drum, and a second rope drive for controlling the test load. This segmentation allows each drive to be optimized for its specific function, enabling realistic simulation of load cycles and spool retention while maintaining clear functional separation that manages overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second rope drive serves multiple functions: it controls the test load, simulates varying load conditions during winding operations, and enables realistic spool retention testing. This multi-functionality allows the system to simulate complex real-world operating conditions without requiring multiple separate testing devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If the test load is raised and lowered under constant load, then the ease of operation is high, but the measurement precision of service life and bending cycles is insufficient

Engineering Contradiction:
Improveservice life determinationVSAvoidoperation complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The test system transitions from static constant load conditions to dynamic variable load conditions. The second rope drive enables continuous adjustment of the test load during winding and unwinding operations, allowing simulation of realistic load cycles where the load varies during operation. This dynamic loading significantly improves the precision of service life and bending cycle measurements while maintaining operational simplicity through automated control.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the rope is spooled under constant load, then the ease of operation is high, but the measurement precision of spool retention is insufficient

Engineering Contradiction:
Improvespool retentionVSAvoidoperation complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The spooling process is transformed from a static constant-load operation to a dynamic variable-load process. The second rope drive enables the test load to be adjusted during spooling, allowing measurement of spool retention under realistic operating conditions where load varies during winding and unwinding. This dynamic approach provides accurate spool retention data while keeping the operation simple through automated drive coordination.

Inventive Principle:
Principle #15Dynamics

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

This solution enables more accurate simulation of real-world load cycles and spool retention, allowing for a more reliable determination of service life and permissible bending cycles, and allows for testing of longer ropes and varied load conditions, reducing the complexity of the test setup and improving safety.

Implementation Method 1

a deflection system comprising at least one deflection pulley for deflecting the test rope

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a test rope drive for winding and unwinding the test rope via the deflection system

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 3

a test load to load the test rope

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 4

an additional rope drive for winding and unwinding a safety rope and/or said test rope

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2702387B1Rope test stand
Publication Date: 2015.03.11 LIEBHERR COMPONENTS BIBERACH GMBH
  • EP2702387B1 patent drawingFigure 1
  • EP2702387B1 patent drawingFigure 2
  • EP2702387B1 patent drawingFigure 3

AI summary

The invention relates to a rope test stand for testing a test rope as to its service life, discard criteria, acceptable number of reverse bending cycles, and/or winding behavior. Said test stand includes a deflection system that comprises at least one deflection sheave for deflecting the test rope, a test rope drive for winding and unwinding the test rope via the deflection system, and a test load for loading the test rope. According to the invention, the rope test stand comprises an additional rope drive for winding and unwinding a safety rope and/or the aforementioned test rope, and a control device for controlling the additional rope drive and/or the test rope drive in a coordinated manner such that the load on the test rope can be differently adjusted for different test rope sections and/or different winding directions and/or different winding cycles and/or different phases of a winding cycle. This allows the load applied to the test rope to be varied by additionally connecting the additional drive to a greater or lesser extent or increasing or reducing the force applied to the rope by the additionally connected additional rope drive without modifying the test load, thus dispensing with the need to rearrange the rope test stand, e.g. replace the test load.