Escalator Shaft Encoder Using Segmented Magnetic Tape
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Solution Overview
Problem
Conventional sensors for escalator shafts, including inductive and optical systems, face delays in feedback during chain breakages and are susceptible to environmental contamination, while magnetic systems are complex and costly to manufacture and retrofit.
Innovation Solution
A sensor system featuring a carrier ring and magnetic measuring tape designed in semicircular elements with connecting means, allowing for a homogeneous magnetic field detection using a single sensor, reducing complexity and cost, and being easier to retrofit onto existing escalator shafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a magnetic ring is split into two halves, then it can be easier to install on existing shafts, but the magnetic field becomes disturbed and sensors can no longer recognize it as homogeneously magnetized
Solution Approach 1:
The magnetic measuring tape is divided into two separate semicircular elements that can be independently installed on the shaft. Each element contains magnetic poles that extend over the connection area, ensuring that when the elements are assembled together, the magnetic field remains homogeneous and recognizable by the sensor.
Solution Approach 2:
The magnetic poles are specifically arranged to extend over the connection areas where the semicircular elements join together. This local concentration of magnetic poles ensures that the connection areas do not create disruptions in the magnetic field, maintaining homogeneity throughout the entire measuring tape.
2Reliability
If two sensors are used to scan the magnetic ring at different positions, then hole detection is more reliable, but the device complexity and cost increase
Solution Approach 1:
The measuring tape is segmented into two semicircular elements with magnetic poles extending over the connection areas. This segmentation allows a single sensor to continuously scan the entire circumference, including the connection areas, eliminating the need for multiple sensors while maintaining detection reliability.
Solution Approach 2:
The magnetic poles are pre-positioned to extend over the connection areas before the semicircular elements are assembled. This preliminary arrangement ensures that when the elements are joined, the magnetic field continuity is maintained, allowing reliable detection by a single sensor without requiring post-assembly adjustments or multiple sensors.
3Measurement precision
If optical sensors are used to monitor the drive shaft, then position coding can be achieved, but the system becomes susceptible to failure when dirt enters the mechanics
Solution Approach 1:
The patent replaces optical sensing with magnetic sensing. The magnetic measuring tape with semicircular elements and extending magnetic poles creates a magnetic field that is detected by a magnetic sensor. This substitution eliminates the susceptibility to dirt and contamination that plagues optical systems, as magnetic fields are not affected by environmental factors.
4Reliability
If inductive sensors monitor chain teeth, then chain breakage can be detected, but the feedback is significantly delayed due to slow chain movement
Solution Approach 1:
The patent replaces indirect mechanical monitoring of chain teeth with direct magnetic monitoring of the drive shaft's position coding. The magnetic sensor continuously reads the magnetic poles on the rotating measuring tape, providing real-time feedback about shaft position and speed changes, thereby eliminating the time delay associated with monitoring slow-moving chain teeth.
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
The system provides rapid and reliable position coding with minimal environmental susceptibility, enabling timely detection of chain breakages and easy installation on existing escalators, improving safety and reducing maintenance costs.
Implementation Method 1
a magnetic measuring tape arranged on its circumference, the carrier ring and the measuring tape being designed in two parts in the form of preferably semicircular elements... with the measuring tape having a large number of magnetic poles arranged in the circumferential direction
Data Source
Figure 1~3
Figure 4a~4e
Figure 5a~5e
AI summary
The present invention relates to a measuring transducer (10) for a shaft (40) of an escalator for providing position coding, having a support ring (1) and a magnetic tape measure (2) arranged on the circumference thereof, wherein the support ring (1) and the tape measure (2) are designed in two parts in the form of preferably semi-circular elements (1a,1b,2a,2b) and are able to be connected selectively to one another in a respective connection region (3) via connection means (4) of the support ring (1), wherein the tape measure (2) has a multiplicity of magnetic poles (5i) arranged in the circumferential direction, and wherein the magnetic poles (5i) are arranged in the tape measure (2) such that an individual magnetic pole (5a,5b) in each case extends in the circumferential direction (U) of the measuring transducer over the respective connection region (3) of the support ring (1) and the tape measure (2).