Transit Door Position Sensor Eliminating Readjustment
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Solution Overview
Problem
Existing rotational position sensing devices for transit vehicle door shaft and arm assemblies require readjustment whenever the shaft and arm assembly is adjusted, including height adjustments, leading to inefficiencies in installation and maintenance.
Innovation Solution
A rotational position sensing device with a forked extension that engages an extended member, allowing the position sensor to remain fixed while the shaft adjusts, as the rotating portion axially rotates with the shaft and remains relative to the housing portion, preventing the need for readjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the position sensor is fixed to the shaft and arm assembly using traditional mounting methods, then the sensor can measure the rotational position of the shaft, but the sensor requires readjustment whenever the shaft height is adjusted
Solution Approach 1:
The mounting structure is divided into separate components: a fixed bracket attached to the stationary structure, and an extended member on the position sensor that can independently engage with the fixed bracket. This segmentation allows the sensor to remain fixed in position while the shaft height is adjusted, eliminating the need for readjustment.
Solution Approach 2:
The position sensor is pre-configured with an extended member that engages with the fixed bracket before any shaft height adjustments are made. This preliminary engagement ensures the sensor maintains its calibrated position regardless of subsequent changes in shaft height, preventing the need for readjustment.
2Reliability
If the position sensor is mounted to the structure with fasteners, then the sensor housing is secured, but the shaft portion of the sensor must be secured to the rotating shaft, creating a complex mounting process
Solution Approach 1:
The mounting function is merged into a single integrated fixed bracket that attaches to the stationary structure and provides engagement for the position sensor's extended member. This consolidation simplifies the mounting process while maintaining secure attachment and eliminates the need for separate mounting steps.
3Adaptability or versatility
If the shaft and arm assembly is adjusted for height, then the door system can accommodate different configurations, but the position sensor loses its calibration and requires readjustment
Solution Approach 1:
The fixed bracket acts as an intermediary between the stationary structure and the position sensor. It provides a stable reference point that remains unchanged during shaft height adjustments, allowing the sensor to maintain its calibration while the shaft and arm assembly adapts to different configurations.
Data Source
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AI summary
A rotational position sensing device for sensing rotation of an axially adjustable shaft of a shaft and arm assembly of a door that does not require readjustment after the shaft and arm assembly are adjusted includes a fixed bracket supporting a post, a position sensor having an upper portion, a lower portion and an extended portion, and a rotating portion. The extended portion extends from the upper portion of the position sensor and constrains the post of the bracket such that the upper portion of the position sensor is unable to axially rotate relative to the bracket. The rotating section is adapted to be fixed to the shaft and engage with the lower portion of the position sensor, such that the rotating portion rotates relative to the upper portion of the position sensor.