Helical Actuator Alignment for Twist-Free Piston Retraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fluid-operated linear actuators face issues with twisting of the piston within the cylinder, leading to unpredictable orientation and increased drag, particularly in high-speed and high-pressure applications, such as aircraft emergency releases and retractable castor wheels, due to the lack of effective constraints which add weight and complexity.
Innovation Solution
A linear actuator design featuring a helical orientation surface and a follower that moves along this surface to achieve a predetermined angular orientation of the actuator components, reducing twisting and drag by engaging only when necessary, and optionally using resilient mounting for impact cushioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a constraint arm with central hinge is used to prevent piston twisting, then rotational alignment is achieved, but weight increases and space requirements increase
Solution Approach 1:
The invention extracts the rotational constraint function from a separate mechanical constraint arm and integrates it directly into the piston-cylinder interface through helical orientation surfaces. This eliminates the need for the heavy external constraint arm while maintaining the rotational alignment function.
Solution Approach 2:
The helical orientation surfaces merge the rotational constraint function with the existing piston and cylinder components. The follower feature on the piston engages with the helical orientation surface on the cylinder, combining alignment and sealing functions into the basic actuator structure.
2Stability of the object's composition
If a constraint arm with central hinge is used to prevent piston twisting, then rotational alignment is achieved, but the projected space increases drag
Solution Approach 1:
The invention removes the external constraint arm that projected laterally and caused drag. By integrating the constraint function into the piston-cylinder interface through helical surfaces, there is no external projection to increase aerodynamic drag.
3Weight of moving object
If helical orientation surface and follower are used, then rotational alignment is achieved without constraint arm, but impact forces increase during engagement
Solution Approach 1:
The invention provides beforehand cushioning by allowing axial movement of the helical orientation surface relative to the follower. This relative movement absorbs impact forces during engagement, preventing excessive shocks while maintaining rotational constraint.
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 effectively prevents twisting and random orientation of actuator components, reducing drag and wear, while maintaining lightweight construction and minimizing space requirements, thus enhancing operational stability and efficiency.
Implementation Method 1
a helical orientation surface is disposed about the operating axis and in a fixed angular position relative to the first component; in which a follower is disposed in a fixed angular position about the operating axis relative to the second component; and in which when the first and second components are moved relative to one another towards an end of the operating axis, the follower moves from a disengaged condition in which the free relative rotation of the first and second components is allowed, to a condition in which the follower engages and moves along the helical orientation surface to rotate the first and second components relative to one another about the operating axis
Data Source
AI summary
An e.g. fluid powered linear actuator is provided with a helical orientation surface in a fixed angular position relative to a first component; and a follower in a fixed angular position relative to a second component. When the first and second components are moved towards one another as the actuator is retracted, the follower engages and moves along the helical orientation surface to rotate the first and second components to a predetermined relative angular position.