Decoupling Shaft Locking for Manual and Pneumatic Actuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mechanical disconnect mechanisms for power trains in aircraft lack efficient and reliable methods for manual actuation without electrical power or pneumatic air supply, particularly in situations requiring emergency disconnect or maintenance.
Innovation Solution
A system featuring a decoupling shaft with axial and rotational movement, locked by pneumatic pistons and cams, allowing for both pneumatic and manual actuation. The system includes anti-rotation pins and helical threads for manual operation, enabling remote command and independent rotation of connected shafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pneumatic locking pistons are used to lock the decoupling shaft in position, then the reliability of the locking mechanism is improved, but the device complexity increases due to the need for pneumatic chambers and solenoids
Solution Approach 1:
The locking piston acts as an intermediary element that translates pneumatic pressure into mechanical locking action. The piston is biased by a spring and controlled by pneumatic pressure from the chamber, providing a reliable locking mechanism that can be actuated remotely via solenoids while isolating the complexity of the pneumatic system from the critical locking function.
2Adaptability or versatility
If manual actuation capability is added to the pneumatic system, then the adaptability of the system is improved, but the device complexity increases due to additional components like anti-rotation pins and helical threads
Solution Approach 1:
The decoupling shaft is designed with dual functionality: it can be actuated pneumatically through the locking pistons for normal operation, and manually through the anti-rotation pin and helical threads for emergency or maintenance situations. This multi-functionality allows a single mechanism to handle both automated and manual actuation requirements.
Solution Approach 2:
The system dynamically switches between pneumatic and manual actuation modes based on operational needs. The anti-rotation pin can be inserted or removed to enable or disable manual actuation, while the helical threads provide a mechanical interface that engages only when needed, allowing the system to adapt its actuation method to the current situation.
3Reliability
If locking pistons are biased radially inward to engage grooves, then the locking reliability is improved, but the force required to actuate the piston increases
Solution Approach 1:
The cam surface incorporated in the locking piston provides a curved, progressive engagement path. As the piston moves axially, the cam surface gradually lifts the piston radially outward, reducing the peak force required compared to a direct radial engagement. This curved geometry distributes the actuation force over a longer distance, making the system easier to actuate while maintaining reliable locking.
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 system effectively mechanically separates rotating shafts, enabling remote and manual actuation, ensuring continued operation of critical aircraft systems during maintenance or under maximum load conditions.
Implementation Method 1
The first locking piston can be configured to move radially outward against its bias with a first solenoid pressurizing the first compartment
Implementation Method 2
The first locking piston is biased radially inward to engage a first groove in the decoupling shaft to lock the decoupling shaft in the second position
Implementation Method 3
The anti-rotation pin can be engaged in a diametrical groove through a decoupling shaft to prevent rotation of the decoupling shaft relative to the housing during pneumatic operation
Implementation Method 4
A set of axially extending helical threads in the first end of the decoupling shaft can be configured to engage a bolt to facilitate manual axial actuation of the decoupling shaft
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system includes a decoupling shaft (114) engaged in a housing (122) for axial movement relative to the housing along a longitudinal axis of the decoupling shaft between a first position for coupling and a second position for decoupling. The decoupling shaft is engaged in the housing for rotational movement relative to the housing about the longitudinal axis. A first locking piston (144) is engaged to the housing, operatively connected to a first compartment of a pneumatic chamber of the housing. The first locking piston is biased radially inward to engage a first groove (148) in the decoupling shaft to lock the decoupling shaft in the second position. A second locking piston (152) is engaged to the housing, operatively connected to a second compartment of the pneumatic chamber. The second locking piston is biased radially inward to engage a second groove (156) in the decoupling shaft to lock the decoupling shaft in the first position.