Elevator Brake Monitoring via Inductive Proximity Sensor
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Solution Overview
Problem
Existing solutions for monitoring the operational state of elevator machinery brakes, such as micro switches and proximity sensors, are unreliable and face challenges in accuracy and installation due to environmental factors like electromagnetic interference and limited space, particularly in detecting small displacements of brake parts.
Innovation Solution
An inductive proximity sensor arrangement is implemented in the machinery brake, where a target is positioned to move within or out of the sensor's operational area, generating distinct output signals for normal and abnormal states, with a control unit generating an alarm for abnormal conditions, and the target is designed with a ferromagnetic material and optimal dimensions to ensure accurate detection of lateral displacements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If micro switches are used for detecting mutual positions of brake parts, then position detection is achieved, but reliability and accuracy are insufficient due to electromagnetic interference and limited detection capability for small displacements
Solution Approach 1:
The patent replaces mechanical micro switches with an inductive proximity sensor that uses electromagnetic induction to detect the position of the armature part. This substitution eliminates the mechanical contact and electromagnetic interference issues of micro switches while achieving reliable detection of small displacements (0.15 mm scale) through non-contact sensing of the ferromagnetic target's position changes.
2Ease of operation
If micro switches are installed in the machinery brake, then position monitoring is enabled, but installation is prevented due to lack of space and electromagnetic interference
Solution Approach 1:
The inductive proximity sensor replaces micro switches by using electromagnetic induction through a ferromagnetic target instead of mechanical contact. This allows installation in the constrained space of the machinery brake without being affected by electromagnetic interference from the electromagnet, as the sensor detects position changes through magnetic field interactions with the ferromagnetic material rather than direct electromagnetic signals.
3Force
If the machinery brake operates under heavy forces and environmental variables, then braking function is achieved, but displacement of parts occurs causing misoperation
Solution Approach 1:
The patent implements preliminary monitoring of the armature part's position using the inductive proximity sensor and ferromagnetic target arrangement. By continuously detecting position changes before they lead to misoperation, the system can alert operators to potential issues caused by thermal expansion, vibration, or load variations, allowing preventive maintenance before structural instability causes elevator shutdown.
4Measurement precision
If proximity sensors are used as disclosed in US 2002/100646 A1, then position indication is achieved, but reliability remains insufficient in the harsh environment of elevator brakes
Solution Approach 1:
The patent uses an inductive proximity sensor that operates through electromagnetic induction with a ferromagnetic target, replacing conventional proximity sensors that may be affected by electromagnetic interference. The ferromagnetic target provides a reliable magnetic signature that the inductive sensor can detect consistently under harsh conditions including heavy forces, vibration, and temperature variations, ensuring reliable position indication throughout the sensor's operational life.
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 provides reliable monitoring of the operational state of elevator brakes, detecting even small displacements and preventing misoperation by generating accurate alarm signals, thus ensuring safe and efficient elevator operation.
Implementation Method 1
an inductive proximity sensor mounted to one of the following: the frame part, the armature part and a target mounted to the other of the following: the frame part, armature part
Implementation Method 2
the target is designed with a ferromagnetic material
Data Source
Figure 1~2B
Figure 3A~3B
Figure 4~5D
AI summary
The present invention relates to a machinery brake for an elevator. The machinery brake comprises a frame part (120) comprising an electromagnet and an armature part (110), wherein the machinery brake further comprising an inductive proximity sensor (122) mounted to one of the following: the frame part (120), the armature part (110) and a target (124) mounted to the other of the following: the frame part (120), armature part (110). The inductive proximity sensor (122) and the target (124) are mounted with respect to each other so that in a normal state of the machinery brake the target (124) resides within an operational area of the inductive proximity sensor (122) and in an abnormal state of the machinery brake the target (124) resides at least partly outside the operational area of the inductive proximity sensor (122). The invention also relates to a method therein.