Elevator Hoistway Access Control via Car Positioning
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Solution Overview
Problem
Current elevator systems face issues with dust and passenger items falling into the hoistway due to a 30 mm clearance between doors, necessitating frequent cleaning and maintenance access, which increases safety volume requirements and operational inefficiencies.
Innovation Solution
A hoistway access system that includes an access switch connected to an elevator system controller, allowing technicians to safely access the pit by controlling the elevator car's movement and activating safety mechanisms to create a defined safety volume, enabling maintenance from within the car without the need for a large safety volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a 30 mm clearance is provided between landing door and car door, then dust and items can fall into the hoistway requiring frequent cleaning, but eliminating the clearance would prevent items from falling in
Solution Approach 1:
The patent extracts the harmful clearance gap between the car door and landing door by introducing a door wedge that fills this space. The wedge is inserted between the car door and the door frame, effectively eliminating the 30 mm clearance that allows dust and items to fall into the hoistway, thereby preventing contamination without affecting door functionality
Solution Approach 2:
The door wedge acts as an intermediary element between the car door and the door frame. This wedge-shaped component fills the clearance gap, serving as a barrier that prevents dust and dropped items from entering the hoistway while allowing the door to maintain its opening and closing operations
2Ease of operation
If mechanics access the pit by opening the lowest landing door and climbing down the pit ladder, then the pit can be cleaned and items retrieved, but a large safety volume is required protecting technicians
Solution Approach 1:
Instead of having technicians climb down into the pit from the landing, the patent inverts the approach by lowering the elevator car itself to provide access. The car is positioned to create a working platform above the pit, allowing technicians to access and clean the pit from the car rather than entering the pit directly, thereby eliminating the need for a large safety volume
Solution Approach 2:
The elevator car serves as an intermediary platform between the landing and the pit. By positioning the car to overlap with the pit area, it provides a safe working platform for technicians to perform maintenance and cleaning operations without requiring them to enter the hazardous pit space, thus eliminating the need for a large safety volume
3Extent of automation
If the elevator car is controlled to travel up or down a set distance and stop for a given time, then automatic well access mode provides structured access, but unauthorized activation could cause safety issues
Solution Approach 1:
The system performs preliminary actions by automatically positioning the elevator car to a predetermined location that provides access to the pit before maintenance operations begin. The car travels up or down a set distance and stops for a given time to establish the proper working position, ensuring safe and structured access to the pit area
Solution Approach 2:
The system incorporates feedback mechanisms to monitor and control the automatic well access mode. The controller tracks the car's position, movement distance, and stop duration to ensure proper positioning while detecting unauthorized activation attempts, thereby maintaining safety while providing automated access functionality
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A hoistway access system for an elevator includes an access switch positioned at a selected landing floor 34 of an elevator and operably connected to a controller 46. A remote controlled lock 48 is located at landing doors of a landing floor providing access to a hoistway pit 36, and is operably connected to the controller. A safety actuation system is operably connected to an elevator car and operably connected to the controller. The controller is configured to command a drive system to drive the elevator car to an upper location when the access switch is activated, to define a selected safety volume in the hoistway defined by the hoistway pit and the elevator car, command engagement of the safety actuation system to stop and hold the elevator car, and command the lock to unlock when the safety actuation system is engaged, thereby allowing access to the hoistway via the landing doors.