Spring-Return Mode Selection Valve for RAT Re-Stow Pumps
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Solution Overview
Problem
Existing mode selection valves for RAT re-stow pumps are physically demanding and require multiple rotational movements, making them inconvenient to operate while still needing to meet safety standards for quick return to the default position.
Innovation Solution
A mode selection valve assembly with a rotary spring that biases the operating end to a default rotational position, allowing easy rotation to the STOW mode and automatic return to the ARM mode within 50 seconds, facilitated by a rotary force and a spring mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heavy mechanical rotary valve is used for mode selection, then the valve can provide reliable mode switching, but it requires significant physical effort and multiple rotational movements to operate
Solution Approach 1:
The patent applies a spring mechanism that provides a counteracting force to the heavy rotary valve, reducing the physical effort required to rotate it. The spring is pre-loaded to compensate for the weight and inertia of the valve, allowing maintenance personnel to rotate the valve with minimal force between the ARM and STOW positions.
Solution Approach 2:
The patent introduces a spring-loaded mechanism that dynamically assists the rotation of the heavy valve. The spring force is engaged during rotation to reduce the effort needed, and the system transitions from a static heavy valve to a dynamic system where the spring actively participates in the motion, enabling easier operation while maintaining reliability.
2Ease of operation
If a spring mechanism is added to reduce physical effort, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent merges the spring mechanism with the existing valve body and operating handle, integrating the complexity reduction into the overall valve assembly rather than adding a separate complex mechanism. The spring is housed within the existing valve structure, and its operation is combined with the rotational motion already required for mode selection, thereby reducing physical effort without proportionally increasing device 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
Provides a simple and efficient operation of the mode selection valve, reducing physical effort and ensuring compliance with safety standards by enabling quick return to the default position.
Implementation Method 1
a rotary spring secured in the housing and connected at a first end to the housing and at a second end to the operating end, the spring configured to rotationally bias the operating end to a first rotational position
Data Source
AI summary
A mode selection valve assembly includes a first end having a housing and an operating end located within the housing and rotatable relative thereto on application of a rotary force by a user. The assembly also includes a conduit end fixed to rotate with the operating end. The conduit end is formed by a cylindrical wall defining a conduit therethrough and an opening formed through the wall in fluid communication with the conduit. The assembly also includes, a rotary spring secured in the housing and connected at a first end to the housing and at a second end to the operating end. The spring is configured to rotationally bias the operating end to a first rotational position relative to the housing such that the opening of the conduit end is at a first rotary position relative to the housing.