Double-Action Reverse Thrust Actuator for Compact Maintenance Access
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Solution Overview
Problem
Conventional actuators used in turbojet reverse thrust systems require elongation to achieve greater displacement for maintenance access, leading to space constraints within or outside the nacelle, as they occupy longer lengths in their normal state.
Innovation Solution
A double-action actuator system comprising a first rod, a concentric hollow rod, and an actuator shaft that pivots, linked using nut and screw mechanisms with locking means, allowing combined rod movements to occupy less length in the retracted state, enabling both normal operation and extended access without lengthening the actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the actuator length is increased to achieve greater displacement for maintenance access, then the displacement capability is improved, but the actuator becomes difficult or impossible to incorporate within or outside the nacelle due to space constraints
Solution Approach 1:
The patent employs a telescopic rod mechanism where one rod is nested within another concentric rod. The inner rod can extend relative to the outer rod, providing additional displacement when needed for maintenance access, while retracting to minimize the overall actuator length during normal operation, thus resolving the contradiction between displacement capability and space constraints.
Solution Approach 2:
The actuator transitions from a static fixed-length design to a dynamic telescopic design. The rod system can dynamically adjust its length between a retracted state (minimal length for incorporation) and an extended state (greater displacement for maintenance), allowing the actuator to adapt to different operational requirements without permanently occupying excessive space.
2Device complexity
If a single actuator is used for both normal operation and maintenance access, then device complexity is reduced, but control precision and reliability deteriorate without proper locking mechanisms
Solution Approach 1:
The locking means are pre-configured to automatically engage at specific positions during the rod extension/retraction cycle. This preliminary action ensures that the rod is securely locked in either the retracted position (for normal operation) or the extended position (for maintenance access), preventing accidental movement and ensuring reliable control despite the simplified single-actuator design.
Solution Approach 2:
The locking means act as an intermediary mechanism between the single actuator and the dual-function requirements. It mediates the transition between normal operation and maintenance access modes by providing secure positional control, allowing one actuator to reliably control two different states without requiring separate actuators for each function.
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
This design allows for efficient deployment and retraction of the actuator, facilitating both normal service and maintenance access with a single actuator, reducing the overall length required and preventing accidental retraction during operation.
Implementation Method 1
links using nut and screw connect the second rod on the one hand to the first rod and on the other to the actuator shaft
Data Source
AI summary
The turbojet includes, linking two of its parts as a main nacelle portion and a rear nacelle portion, a device which moves them relative to one another, for example in order to open a reverse gas thrust slot. The device includes a sleeve and two rods which are coaxial connected together by two screw links and two locking devices which may be engaged independently, such that the deployment of one of the rods results in the opening of the slot and the movement of the other rod, controlled by the same device, only occurs under specific turbojet maintenance circumstances.