Piston Cylinder Indicator Pin and Locking Mechanism
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Solution Overview
Problem
Existing pressure cylinders used in the railroad industry for coal car doors lack a visible indicator for the end of the return stroke and a secondary internal lock, making it difficult for operators to confirm the fully closed and locked position visually and securely.
Innovation Solution
A piston and cylinder assembly with an indicator pin that extends outward from the cylinder housing and retracts when the piston reaches the end of its return stroke, and a locking pin that mechanically secures the piston in the retracted position, utilizing a retracting device and spring bias to provide visual and mechanical confirmation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a remote electric signal indicator is used, then automation is improved, but visibility for easy inspection by the operator deteriorates
Solution Approach 1:
The patent introduces an intermediary mechanical indicator pin that translates the remote piston position into a locally visible signal at the cylinder housing. The pin acts as a mediator between the automated piston movement and the operator's visual inspection need, providing tactile and visual confirmation without requiring remote electronic signals.
2Device complexity
If no secondary internal lock is provided, then device complexity is reduced, but reliability of the locked position deteriorates
Solution Approach 1:
The patent implements a secondary internal locking pin that engages in advance with the piston rod to prevent unintended movement before it can occur. This preemptive locking mechanism provides an additional layer of security against failures of the primary external locking mechanism, enhancing overall system reliability.
3Measurement precision
If an indicator pin is added to show piston position, then measurement precision of piston position is improved, but device complexity increases
Solution Approach 1:
The patent merges the indicator pin function with the existing cylinder housing structure, integrating the indication mechanism into the housing rather than adding a separate external indicator system. The pin is resiliently biased within the housing and engages directly with the piston rod movement, combining multiple functions into a single integrated component.
4Reliability
If a locking pin is added to mechanically secure the piston, then reliability of the locked position is improved, but device complexity increases
Solution Approach 1:
The patent implements a nested locking mechanism where the internal locking pin is housed within the cylinder housing, similar to a nested doll structure. The locking pin can be inserted through the housing wall to engage with the piston rod, providing a secure locked position while maintaining a compact integrated design that minimizes overall complexity.
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 solution provides a visible indication and mechanical locking mechanism, ensuring the piston is at the end of its return stroke, enhancing operator confirmation and securing the cylinder in the closed position.
Implementation Method 1
The spring member biases the plunger rod and indicator pin toward the extended position against the retracting motion caused by the tapered interior end of the piston and rod assembly
Data Source
AI summary
An indicator device for a piston and cylinder assembly has an indicator pin with a distal end indicator section for extending out of a side wall of a piston cylinder assembly when the piston and rod assembly is not at the end of its return stroke. A retracting device retracts the indicator pin when the piston and rod assembly moves to the end of its return stroke and has an optional internal lock that mechanically axially affixes the piston and rod assembly.