Brake Chamber Stroke Indicator Using String Pot Gauge
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Solution Overview
Problem
Existing brake stroke indicator systems for vehicle air brake systems face challenges such as obscure reference locations, environmental debris accumulation, and the need for specific viewing angles, leading to difficulties in accurately determining system adjustment and maintenance needs.
Innovation Solution
A string pot gauge system with a chemical and abrasion-resistant filament is mounted on the brake air chamber, providing a visual indication of brake push rod stroke through colored zones on a rotating disc, allowing easy viewing and minimizing debris accumulation, with embodiments adaptable for various brake systems including disc brakes and pneumatic spring actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stationary reference bracket is used for visual indication, then the system provides a reference for measurement, but the bracket accumulates environmental debris such as ice and grime which obscures the view and causes false readings
Solution Approach 1:
The patent extracts the reference indication function from a stationary external bracket and integrates it into the moving pushrod assembly itself. The reference mark is now attached to the pushrod that moves with the brake mechanism, eliminating the stationary bracket that collected debris. This allows the reference indication to be viewed without being exposed to environmental accumulation problems.
Solution Approach 2:
The patent introduces a string or filament as an intermediary element that connects the pushrod movement to a visible indicator. Instead of directly viewing a mark on a stationary bracket, the string transmits the movement information to a rotating disc with colored zones that can be viewed from a distance, mediating between the mechanical movement and the visual indication.
2Measurement precision
If a visual mark is placed on the pushrod base, then the system indicates stroke position, but the reference location becomes obscure and difficult to see from accessible locations
Solution Approach 1:
The patent transforms the indication from a linear position mark into a rotational display with colored zones on a disc. This dimensional change allows the indicator to be viewed from various angles and distances, making it accessible for inspection without requiring the inspector to be in an obscure location underneath the vehicle. The rotating disc presents different colored zones (green, yellow, red) that are visible from accessible viewing positions.
3Measurement precision
If a stationary bracket is used for reference viewing, then the system provides a fixed reference envelope, but the bracket requires specific viewing angles for accurate measurement
Solution Approach 1:
The patent makes the reference indication dynamic by attaching it to the moving pushrod and using a rotating disc display. Instead of a fixed bracket requiring precise angular alignment, the rotating disc with colored zones can be viewed from multiple angles as it rotates, eliminating the need for specific viewing angle requirements while maintaining measurement accuracy through the colored zone indications.
4Reliability
If environmental buildup occurs on the bracket, then debris accumulates and damages parts, but the indication system continues to operate
Solution Approach 1:
The patent removes the vulnerable stationary bracket from the system and extracts its reference function into the moving pushrod assembly. By eliminating the stationary external bracket that served as a debris collection point, the system prevents environmental buildup from occurring, thereby protecting parts from damage while maintaining reliable operation of the indication system.
Data Source
AI summary
A brake chamber stroke indicator system for a brake system including a brake air chamber includes an indicator rod or a string pot gauge including a housing with an indicator rotatably positioned within the housing. A string has a first end attached to the indicator of the string pot gauge. A spring urges the indicator to rotate in a first direction whereby the string is retracted into the housing. The second end of the string is attached to a brake push rod or a pressure plate. The indicator rod is mounted by a base onto a pressure plate.