Actuating Device Backstopping and Overrunning Clutch Mechanism
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Solution Overview
Problem
Existing actuating devices fail to meet the complex design requirements of new applications, particularly in scenarios requiring mechanical advantage to overcome significant resistance, such as opening an aircraft door in flight, and often rely on electrical, hydraulic, or pneumatic systems.
Innovation Solution
The design incorporates a backstopping clutch to transmit torque in one direction while preventing back-driving and an overrunning clutch that allows direct actuation of the load, enabling mechanical advantage through geared configurations and independent operation from aircraft systems, allowing a single user to move substantial loads without assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a geared configuration is used to provide mechanical advantage, then the force output is improved, but the device complexity increases
Solution Approach 1:
The actuating device is divided into functionally independent clutch mechanisms (backstopping clutch and overrunning clutch) that can operate separately. This segmentation allows the geared configuration to provide mechanical advantage when needed while preventing the entire system from becoming inoperable due to complexity, as each clutch can be engaged or disengaged independently based on operational requirements.
Solution Approach 2:
The clutch mechanisms are designed to dynamically engage and disengage based on operational conditions. The backstopping clutch dynamically transmits torque only in the driving direction, while the overrunning clutch allows free rotation in the driving direction but transmits torque in the reverse direction. This dynamic behavior allows the system to adapt its complexity level - using geared mechanical advantage only when required by the operational situation.
2Power
If electrical, hydraulic, or pneumatic systems are used to move substantial loads, then the power output is improved, but the device complexity and dependency on external systems increases
Solution Approach 1:
The actuating device is designed as a self-contained mechanical system that does not require external electrical, hydraulic, or pneumatic systems. The clutch mechanisms themselves provide the power transmission and control functions, with the input device (manual or motor-driven) directly coupled to the clutch assembly. This self-service approach eliminates dependency on external systems while maintaining the ability to move substantial loads through purely mechanical means.
Solution Approach 2:
The patent extracts and eliminates the need for external electrical, hydraulic, or pneumatic systems by implementing a purely mechanical solution. The clutch mechanisms are designed to handle all power transmission requirements independently, removing the complexity associated with integrating multiple external system types and their associated control, sealing, and power supply requirements.
3Reliability
If a backstopping clutch is used to prevent back-driving, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The backstopping clutch is integrated with the overrunning clutch in a combined clutch assembly where both mechanisms work together within a single housing. The backstopping clutch prevents back-driving of the input device, while the overrunning clutch allows free rotation in the driving direction. By merging these functions into a single integrated component rather than separate assemblies, the reliability benefit is achieved with minimal increase in overall device complexity.
Solution Approach 2:
The clutch mechanisms serve as intermediary elements between the input device and the load, providing controlled torque transmission. The backstopping clutch acts as an intermediary that selectively blocks reverse torque while allowing forward torque transmission, and the overrunning clutch provides a similar function in the opposite rotational direction. These intermediary clutches protect the input device from back-driving forces without requiring complex protective systems.
4Ease of operation
If an overrunning clutch is used to allow direct actuation, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The overrunning clutch is designed with dynamic engagement characteristics that automatically adapt to operational conditions. When the load needs to be moved directly without resistance, the clutch allows free rotation and direct actuation. When torque transmission is required, the clutch automatically engages to transmit torque from the input device to the load. This dynamic behavior provides ease of operation across different operational scenarios without requiring manual switching or complex control mechanisms.
Solution Approach 2:
The overrunning clutch mechanism is self-regulating and does not require external control signals or manual intervention to determine when to engage or disengage. The clutch automatically responds to the direction and magnitude of applied torques, providing direct actuation capability when needed while seamlessly transitioning to torque transmission mode when required. This self-service operation simplifies the user interface and control system while maintaining operational flexibility.
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 configuration enables efficient and independent operation of aircraft doors during emergencies, providing mechanical advantage when needed and allowing direct movement of the door without resistance, reducing the need for complex systems and enabling single-user operation.
Implementation Method 1
A backstopping clutch is configured to transmit the torque only when in one direction and to prevent back-driving of the input device in the opposite direction
Implementation Method 2
An overrunning clutch is configured to include a driven member moved by a driving member in response to the transmitted torque in the input direction
Data Source
AI summary
An actuator is configured for transmitting a force or torque to a load. In one example configuration, the actuator includes an input device configured to apply an output force. A backstopping clutch is configured to transmit torque only in the input direction and to prevent back-driving of the input device. An overrunning clutch is configured to include a driven member moved in response to the transmitted torque in the input direction. The load may be moved in response to the driven member, or the load may be moved by a force applied directly to the load.