Elevator Overspeed Governor Rope Tensioning With Spring-Failure Detection
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Solution Overview
Problem
Existing rope tensioning devices for elevator overspeed governors are complex, require guidance for springs, and extension springs are unsafe due to potential failure leading to no force generation, while broken compression springs generate reduced force.
Innovation Solution
A rope tensioning device using parallel extension springs with a tiltable connecting member and a detection mechanism to activate a switch when the spring fails, ensuring immediate detection of reduced tension and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If extension springs are used for rope tensioning, then the device is simpler and more compact, but safety is compromised because spring failure results in no force generation
Solution Approach 1:
A tiltable connecting member is introduced as an intermediary element between the extension spring and the lever arm. This connecting member tilts when the spring fails, providing an intermediate detection mechanism that triggers the safety circuit without requiring the spring to maintain continuous force generation
Solution Approach 2:
The system incorporates a feedback mechanism where the tilt of the connecting member is detected by a switch that activates the safety circuit. This continuous monitoring provides real-time feedback on spring status, allowing immediate response to spring failure conditions
2Reliability
If compression springs are used for rope tensioning, then safety is maintained as broken springs still generate reduced force, but the device becomes complex requiring guidance for springs and cannot be produced with pretension force
Solution Approach 1:
Instead of using compression springs that require complex guidance mechanisms, the patent inverts the approach by using extension springs combined with a tiltable connecting member. This inversion simplifies the overall device structure while maintaining safety through the detection mechanism rather than relying on the spring's ability to generate force after failure
3Reliability
If a detection mechanism is added to detect spring failure, then safety is improved, but device complexity increases
Solution Approach 1:
The detection mechanism is merged with the existing structural elements of the tensioning device. The tiltable connecting member serves dual purposes: it transmits force during normal operation and simultaneously acts as the detection element when the spring fails. The switch is integrated into the existing assembly, eliminating the need for separate detection components
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 solution provides a safer, simpler, and more compact rope tensioning device that reliably detects spring failure, ensuring immediate safety circuit activation and preventing unsafe conditions.
Implementation Method 1
two extension springs arranged in parallel; a first connecting member mounted on the fixed support member and a second connecting member mounted on the lever arm, each extension spring having one end connected to the first connecting member and the other one to the second connecting member
Implementation Method 2
a lever arm hinged to the pulley; a fixed support member, to which one end of the lever arm is hinged
Implementation Method 3
means for detecting a tilt of the tiltable connecting member beyond a predetermined angle with respect to its working position
Data Source
AI summary
A rope tensioning device for an overspeed governor of an elevator, including a pulley; a lever arm hinged to the pulley; a fixed support member, to which one end of the lever arm is hinged; two extension springs arranged in parallel; a first connecting member mounted on the fixed support member and a second connecting member mounted on the lever arm, each extension spring having one end connected to the first connecting member and the other one to the second connecting member, at least one of the first and second connecting members is mounted so as to be tiltable around a hinge axis, said at least one tiltable connecting member being held in a predetermined working position by the two extension springs; means for detecting a tilt of said at least one tiltable connecting member beyond a predetermined angle with respect to its working position.