Seat Actuator Motion Constraint for High-G Load Transfer
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Solution Overview
Problem
Actuators in passenger seats, such as those in aircraft, deform significantly during high g-force events, leading to failure due to excessive loads, which compromises their functionality and safety.
Innovation Solution
A device is introduced that constrains actuator motion during dynamic events by using clips and mechanical stops to momentarily stop rotational motion, allowing load transfer to the seat frame, thereby minimizing actuator deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the actuator allows full rotational motion during normal use, then the seat back can adjust between upright and reclined positions, but during high g-force events the actuator shaft buckles and deforms significantly
Solution Approach 1:
The patent implements a dynamic constraint system where the mechanical stop and clip assembly transition from a non-restrictive state during normal operation to a restrictive state during dynamic events. The mechanical stop is positioned to engage only when the seat back exceeds a predetermined forward angle, allowing full range of motion during normal use while providing automatic constraint during high g-force events that cause excessive forward rotation
Solution Approach 2:
The mechanical stop is pre-positioned at a specific angular threshold to prevent excessive forward rotation before it can cause actuator shaft buckling. This preliminary constraint mechanism is ready in advance to counteract the harmful rotational motion during dynamic events, stopping the seat back at a safe angle that protects the actuator from deformative loads
2Strength
If mechanical stops and clips are added to constrain actuator motion during dynamic events, then actuator deformation is minimized, but device complexity increases
Solution Approach 1:
The mechanical stop and clip assembly form a self-activating system that automatically engages and disengages based on the seat back's angular position without requiring external control. When the seat back rotates forward beyond the predetermined angle during a dynamic event, the mechanical stop engages the clip to constrain motion; when the seat back returns to normal position, the constraint automatically releases, eliminating the need for additional sensors, actuators, or control systems
Solution Approach 2:
The clip assembly serves as an intermediary element that transfers the constraint force from the mechanical stop to the actuator shaft. This intermediary mechanism allows the constraint function to be distributed across multiple simple components rather than requiring a single complex device, making the system easier to manufacture and maintain while achieving the same protective effect
Data Source
AI summary
A device for constraining rotational motion of an actuator such as a seat actuator during a dynamic event. The device includes a first part attachable to a fixed frame member and carrying a first clip, and a second part attachable to an actuator and carrying a second clip. Prior to and following a dynamic event sufficient to cause actuator rotational motion the first clip and the second clip are disengaged. During the dynamic event the second clip is configured to engage the first clip to momentarily stop rotational motion of the actuator such that load on the actuator passes through the actuator shaft into the frame. In embodiments, the device is configured to minimize actuator deformation during a dynamic event while allowing a full range of standard motion during normal use of the actuator.