Elevator Door Monitoring With Retroreflective Obstacle Detection
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Solution Overview
Problem
Conventional elevator door monitoring systems require complex wiring of numerous transmitters and receivers, which is cumbersome and inefficient.
Innovation Solution
A door system with a monitoring unit that includes a door frame with a retroreflective surface illuminated by a single light source, using a light sensor to measure angle-resolved intensity of reflected light to detect obstacles, reducing the need for multiple transmitters and receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of transmitters and receivers are used to monitor the door opening, then the monitoring coverage and reliability are improved, but the wiring complexity and installation effort increase significantly
Solution Approach 1:
The patent combines multiple transmitter and receiver functions into a single integrated monitoring unit. This single unit emits light in multiple directions and detects reflected light from the retroreflective surface, eliminating the need for multiple separate transmitters and receivers while maintaining comprehensive monitoring coverage
Solution Approach 2:
The patent introduces a retroreflective surface as an intermediary element on the door frame. This surface reflects light back to the monitoring unit, enabling the single monitoring unit to effectively create multiple virtual beam paths without requiring multiple physical transmitters and receivers
2Area of stationary object
If multiple transmitters and receivers are deployed to ensure comprehensive monitoring, then the monitoring area coverage is improved, but the number of components and installation complexity increase
Solution Approach 1:
The patent merges multiple monitoring functions into a single monitoring unit that can emit light in multiple directions and detect reflected light across a wide angular range, thereby covering the entire door opening area with just one physical unit instead of multiple transmitters and receivers
Solution Approach 2:
The patent transitions from a one-dimensional linear array of multiple transmitters and receivers to a two-dimensional angular coverage approach, where a single monitoring unit emits light and detects reflections across multiple angles to cover the entire door opening area
3Measurement precision
If numerous light-emitting transmitters and light-receiving receivers are used, then the obstacle detection accuracy is improved, but the system reliability is reduced due to more potential failure points
Solution Approach 1:
The patent combines multiple detection functions into a single monitoring unit with integrated light emission and detection capabilities, reducing the total number of components and potential failure points while maintaining obstacle detection accuracy through angle-resolved intensity measurement
4Device complexity
If a single light source is used with retroreflective surface, then the device complexity and wiring effort are reduced, but the monitoring capability must be maintained equivalent to multiple transmitters and receivers
Solution Approach 1:
The retroreflective surface acts as an intermediary that enables a single light source to effectively create multiple virtual light paths by reflecting light back to the monitoring unit at different angles, maintaining comprehensive monitoring capability while using only one physical light source
Solution Approach 2:
The patent replaces the mechanical/electrical system of multiple transmitters and receivers with an optical system using a single light source and retroreflective surface, utilizing optical reflection principles to achieve the same monitoring function with fewer 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
This approach simplifies installation, enhances reliability by minimizing interference, and ensures comprehensive monitoring of the door opening with fewer components, maintaining safety and efficiency.
Implementation Method 1
The door system includes a retroreflective surface on the door frame and a monitoring unit with a light source and light sensor. The light source illuminates the retroreflective surface and the light sensor measures the intensity of the light reflected from the retroreflective surface.
Implementation Method 2
The monitoring unit includes a light sensor designed to measure the intensity of the light reflected from the retroreflective surface. Based on the measured intensity, the monitoring unit determines whether an obstacle is present in the door opening.
Data Source
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AI summary
The invention relates to a door system for a lift installation, said door system comprising a door frame which frames a door opening and comprises a first door post. The door system also comprises a first monitoring unit, which is mounted on the door frame, for monitoring a monitoring region of the door opening. At least one first region of the door frame has a first retroreflective surface which extends over at least 20% of the height of the first door post. The first monitoring unit has a light source which is designed to illuminate the first retroreflective surface with light beams. The first monitoring unit comprises a light sensor which is designed to measure the angle-resolved intensity of the light beams reflected by the retroreflective surface. The first monitoring unit determines an output value based on the angle-resolved intensity by detecting when the angle-resolved intensity falls below a threshold intensity for at least one angle. The output value includes an indication of whether there is an obstacle in the monitoring region.