Elevator Position Sensing Using Tension-Member Pulse Timing
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Solution Overview
Problem
Existing elevator position measurement systems require position measurement tape along the complete height of the hoistway, leading to increased material and installation costs, and occupy valuable space, while being susceptible to temperature-related inaccuracies.
Innovation Solution
An elevator car position measurement system utilizing an elongate tension member with a pulse generator and detector unit to determine the elevator car's position within the hoistway based on the changing length of the tension member as the car moves, eliminating the need for extensive tape installations and providing temperature-independent measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position measurement tape is installed along the complete height of the hoistway, then the elevator position can be measured, but material costs, installation costs, and space requirements increase
Solution Approach 1:
The patent extracts the position measurement function from the traditional tape-based system and relocates it to the elongate tension member (cable) that is already present in the elevator system. By using the existing cable as the measurement medium and placing the detector unit on the elevator car, the system eliminates the need for separate position measurement tape installation, thereby reducing material costs while maintaining measurement capability
Solution Approach 2:
The elongate tension member (cable) serves multiple functions: it provides mechanical support for the elevator car and simultaneously serves as the medium for position measurement through pulse transmission. This multi-functionality eliminates the need for dedicated position measurement tape, reducing material requirements and installation costs
2Measurement precision
If position measurement tape is installed along the complete height of the hoistway, then the elevator position can be measured, but installation costs and space requirements increase
Solution Approach 1:
The patent extracts the position measurement function from the traditional tape-based system and relocates it to the elongate tension member (cable) that is already present in the elevator system. By using the existing cable as the measurement medium and placing the detector unit on the elevator car, the system eliminates the need for separate position measurement tape installation, thereby reducing material costs while maintaining measurement capability
Solution Approach 2:
The patent merges the position measurement system with the existing cable support system. The detector unit mounted on the elevator car uses the cable as a reference medium, combining the mechanical support function and measurement function into a single integrated system, thereby simplifying installation and reducing costs
3Measurement precision
If position measurement tape is installed along the complete height of the hoistway, then the elevator position can be measured, but space requirements in the hoistway increase
Solution Approach 1:
The patent extracts the position measurement function from the traditional tape-based system and relocates it to the elongate tension member (cable) that is already present in the elevator system. By using the existing cable as the measurement medium and placing the detector unit on the elevator car, the system eliminates the need for separate position measurement tape installation, thereby reducing material costs while maintaining measurement capability
4Measurement precision
If position measurement tape is used, then the elevator position can be measured, but the system is susceptible to temperature-related expansions and contractions
Solution Approach 1:
The patent changes the physical state and properties of the measurement medium from a flexible tape to a tensioned cable. The cable's taut state under tension provides dimensional stability and resistance to temperature-induced expansions and contractions, thereby improving measurement reliability in varying temperature conditions
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
Reduces material and installation costs, saves space in the hoistway, and enhances measurement reliability by eliminating the need for temperature compensation, while maintaining accurate elevator positioning.
Implementation Method 1
a pulse generator configured to transmit a pulse along the elongate tension member; a detector unit configured to receive the pulse from the pulse generator
Data Source
AI summary
An elevator system includes an elevator car, an elongate tension member operably connected to the elevator car and configured to move the elevator car, and an elevator car position measurement system. The elevator car position measurement system includes a pulse generator configured to transmit a pulse along the elongate tension member; and a detector unit configured to receive the pulse from the pulse generator after the pulse has been transmitted along a length of the elongate tension member and to record a time at which the pulse is received. One of the pulse generator and the detector unit is arranged to move within the hoistway dependent on a position of the elevator car within the hoistway, such that a length of the elongate tension member along which the pulse is transmitted changes dependent on a position of the elevator car within the hoistway.