Retractable Elevator Apron to Prevent Hoistway Bottom Contact
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Solution Overview
Problem
Elevator aprons hitting the bottom of the hoistway in elevator systems with no or shallow pits cause noise and wear, which existing systems fail to prevent effectively.
Innovation Solution
A retractable apron mechanism that moves between extended and retracted positions, automatically retracting when the elevator car approaches the hoistway bottom, using mechanical components like rollers and pulleys to avoid contact with the hoistway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the apron is extended to close the gap between the elevator car and the landing floor, then the gap closing function is improved, but the apron contacts the hoistway bottom when the car reaches the lowest landing, causing noise and wear
Solution Approach 1:
The apron is designed to be dynamically adjustable between extended and retracted positions. When the elevator car is above the lowest landing, the apron extends to close the gap. When approaching the lowest landing, the apron automatically retracts to prevent contact with the hoistway bottom. This dynamic positioning resolves the contradiction by adapting the apron's state to different operational conditions.
Solution Approach 2:
The length of the apron is changed as a parameter based on the elevator car's position. The apron extends to a first length when the car is above landings and retracts to a second, shorter length when approaching the lowest landing. This parameter change allows the system to maintain gap-closing functionality while avoiding harmful contact with the hoistway bottom.
2Object-generated harmful factors
If a retractable apron mechanism is added to prevent apron contact with the hoistway bottom, then noise and wear are reduced, but the device complexity increases
Solution Approach 1:
The retraction mechanism is designed to activate automatically based on the elevator car's position in the hoistway. The system uses the car's own movement and position information to trigger the apron retraction, eliminating the need for external control systems or additional sensors. This self-service approach reduces complexity while maintaining the noise and wear prevention function.
Solution Approach 2:
The apron retraction is activated in advance when the elevator car approaches the lowest landing, before actual contact with the hoistway bottom would occur. This preliminary action prevents the harmful contact from happening in the first place, allowing the system to use simpler mechanical components rather than requiring complex active control systems to respond to contact.
3Reliability
If the apron is made retractable to avoid hoistway bottom contact, then reliability is improved by preventing damage, but the ease of operation decreases due to automatic retraction requirements
Solution Approach 1:
The automatic retraction system operates autonomously based on the elevator car's position, requiring no manual intervention from operators or maintenance personnel. The system reliably detects when the car is approaching the lowest landing and automatically adjusts the apron position, maintaining both high reliability and ease of operation.
Solution Approach 2:
The retraction mechanism incorporates feedback from the elevator car's position to automatically control apron extension and retraction. This feedback system ensures the apron is in the correct position at all times, improving reliability by preventing damage while maintaining ease of operation through automated control rather than manual adjustment.
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
Prevents apron contact with the hoistway bottom, reducing noise and wear without requiring human intervention, and can be implemented at low cost with reliable mechanical components.
Implementation Method 1
The retraction mechanism may in particular comprise two rollers or three rollers. The at least one roller and the apron tension member may be arranged in a configuration, which is adapted to form, in combination with an activation member provided in the hoistway, a block and tackle
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An elevator car (6) comprises a retractable apron (12), which is movable between an extended position and a retracted position, and a retraction mechanism (14), which is configured for retracting the apron (12) from the extended position into the retracted position when the elevator car (6) approaches the bottom (4a) of a hoistway (4), so that the apron (12) does not contact the bottom (4a) of the hoistway (4).