Elevator Counterweight Blocking Stop Fail-Safe Mechanism
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Solution Overview
Problem
Existing elevator systems lack a reliable mechanism to ensure that the blocking stop for the counterweight is in an active state by default, which is crucial for maintaining sufficient overhead clearance during maintenance procedures, and there is a need for clear visual and tactile indications of the blocking stop's state to ensure safety.
Innovation Solution
The elevator assembly incorporates a locking handle connected to a tension member that automatically activates the blocking stop when the safety device is deployed, with a visual indicator system to confirm the active state, and a mechanism for manual reset to prevent accidental changes, ensuring the blocking stop defaults to the active state for safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blocking stop is held in the inactive state by a tension member under tension, then the device complexity is reduced and operation is simpler, but the safety reliability is compromised because the blocking stop may not be actively engaged
Solution Approach 1:
The system inverts the default state logic by using a locking handle that actively locks the blocking stop in the inactive state, rather than relying on a passive mechanism to maintain the active state. The tension member is used to lock the handle in the inactive position, and releasing the lock allows the blocking stop to default to the active state, ensuring safety through a fail-safe design.
Solution Approach 2:
The blocking stop mechanism is designed to be self-activating through the release of the locking handle. When the locking handle is released (either manually or automatically), the tension member automatically pulls the blocking stop into the active state without requiring additional actuators or complex control systems, making the system self-regulating and reliable.
2Reliability
If the blocking stop is automatically activated by the locking handle mechanism, then the safety reliability is improved, but the ease of operation deteriorates due to the additional manual intervention required
Solution Approach 1:
The system allows automatic activation of the blocking stop through the release of the locking handle, which can be triggered automatically by the safety device or manually by the operator. Once released, the tension member automatically pulls the blocking stop into the active state without requiring additional manual intervention, combining reliability with operational simplicity.
Solution Approach 2:
The locking handle is pre-positioned to hold the blocking stop in the inactive state, and the system is designed so that releasing the handle (either automatically or manually) immediately activates the blocking stop. This preliminary setup ensures that the blocking stop can be activated quickly and reliably without complex sequences or multiple steps.
3Ease of operation
If the locking handle can be manually reset to the first position, then the ease of operation is improved for maintenance procedures, but the safety reliability deteriorates due to the risk of accidental resets
Solution Approach 1:
The system requires deliberate action to reset the locking handle to the first position, rather than allowing accidental movement. The locking mechanism is designed so that the handle can only be moved to the reset position when intentionally operated, and the tension member must be deliberately released, preventing accidental resets while maintaining operational capability for authorized personnel.
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 ensures the blocking stop is reliably in the active state by default, providing both visual and tactile confirmation of its state, enhancing safety during maintenance by preventing accidental resets and ensuring sufficient overhead clearance.
Implementation Method 1
the locking handle comprises an electromagnetic actuator arranged to release the locking member when the safety switch is triggered
Implementation Method 2
a blocking stop, which is connected to a second end of the tension member, and which is moveable between an inactive state, in which the tension member holds the blocking stop in a position in which it does not limit downwards movement of the counterweight
Data Source
AI summary
An elevator assembly (1) comprises an elevator car (2), a counterweight (4), and a safety device (8) located on a roof (9) of the elevator car (2). A locking handle (10) is positioned within the elevator shaft (6), and connected to a first end (12a) of a tension member (12). A blocking stop (14) is connected to a second end (12b) of the tension member (12). The blocking stop (14) is moveable between an inactive state, in which the tension member (12) holds the blocking stop (14) in a position in which it does not limit downwards movement of the counterweight (4), and an active state, in which tension in the tension member (12) is reduced to allow the blocking stop (14) to move to a position in which it limits downwards movement of the counterweight (4).