Traction Sheave Elevator Stall Testing Without Rope Slip Damage
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Solution Overview
Problem
Elevator systems face the risk of stall situations due to rope slackening and slipping, particularly in elevators with coated ropes, which can lead to damage during testing procedures, and existing safety tests may cause further harm to the ropes.
Innovation Solution
A method and elevator system that includes a stopping device to resist the descent of one movable unit while monitoring motor torque and rotation, detecting limit values, and stopping the test sequence before significant rope damage occurs, using a control system to manage the test sequence and prevent excessive rotation or tension drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional stalling test is performed by driving movable unit against buffer until ropes slip or motor stops, then elevator safety behavior is verified, but rope surface damage occurs
Solution Approach 1:
The control system performs preliminary detection of rope tension before the stalling test reaches the dangerous slipping point. By monitoring rope tension in advance and detecting when it approaches critical levels, the system can interrupt the test sequence before rope surface damage occurs, while still having verified safety behavior through the controlled test progression.
Solution Approach 2:
The system implements continuous feedback monitoring of rope tension during the stalling test. When the monitored rope tension indicates approaching dangerous levels, the control system receives feedback and automatically interrupts the test sequence, preventing rope surface damage while maintaining safety verification through controlled monitoring.
2Strength
If high friction coated ropes are used to prevent slipping during operation, then traction is improved, but stall situation likelihood increases during testing
Solution Approach 1:
The control system performs preliminary detection and monitoring of rope tension before the high-friction ropes can cause a stall situation during testing. By detecting tension changes in advance, the system can interrupt the test sequence before the ropes slip, thus maintaining safety while testing elevators equipped with high-friction coated ropes.
Solution Approach 2:
The system implements continuous feedback monitoring of rope tension during testing. When the monitored tension indicates that slipping is imminent due to the high friction characteristics of the coated ropes, the control system receives feedback and interrupts the test, preventing stall situations while still verifying safety behavior.
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 method effectively prevents severe damage to elevator ropes by stopping the test sequence before slipping occurs, ensuring safe and undamaged testing of elevator systems, especially those with sensitive coatings.
Implementation Method 1
The motor can produce torque on the traction sheave, which torque can be needed for producing rotation on the traction sheave or for producing braking effect of the rotation of the traction sheave
Implementation Method 2
The likelihood of a stall situation is most likely to occur in an elevator where the ropes engage very firmly with the traction sheave, for example in an elevator where the rope surface has high friction
Data Source
AI summary
The invention relates to a method for testing a traction sheave elevator, which elevator comprises a traction sheave; a motor for rotating the traction sheave; a roping passing around the traction sheave; and a first movable unit; a second movable unit; and a stopping device for stopping descent of the first movable unit. The method comprises performing a test sequence comprising: rotating the motor to move the second movable unit upwards; resisting downwards movement of the first movable unit with the stopping device during said rotating; monitoring torque of the motor during said rotating, comprising detecting if the torque of the motor reaches, in particular rises to, a limit torque during said rotating; monitoring amount or duration of rotation of the motor or the traction sheave during said rotating, comprising detecting if the amount or duration of rotation after said detecting reaches a predetermined limit amount or limit duration; and stopping the rotating if the amount or duration of rotation after said detecting reaches a predetermined limit amount or limit duration. The invention also relates to an elevator implementing the method.