Double-Shear Seat Track Fitting for High-Load Aircraft Restraint
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Solution Overview
Problem
Conventional pilot or operator seat attachment systems in rotorcraft and aircraft, which rely on single-shear locking pins, are prone to failure under high loading conditions, leading to the seat breaking away from the cockpit or cabin floor.
Innovation Solution
A double-shear secured vehicle seating assembly that utilizes floor track grippers with locking pins extending through multiple walls, providing enhanced stability and resistance to dislodgment under high loading conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-shear locking pin is used to attach the seat to the floor track, then the device complexity is reduced, but the reliability deteriorates under high loading conditions
Solution Approach 1:
The locking mechanism is segmented into multiple shear planes. Instead of a single locking pin with one shear plane, the invention uses a locking pin that extends through multiple floor track grippers, creating multiple shear planes (first shear plane, second shear plane, etc.). This segmentation distributes the load across multiple points, preventing single-point failure and significantly improving reliability under high loading conditions while maintaining relatively simple device complexity.
2Reliability
If the locking pin extends through multiple floor track grippers, then the reliability improves, but the device complexity increases
Solution Approach 1:
The locking pin serves multiple functions simultaneously: it locks multiple floor track grippers to the floor track, provides multiple shear planes for load distribution, and maintains structural integrity across the entire seat assembly. This multi-functionality improves reliability without proportionally increasing device complexity, as the same component (locking pin) performs multiple critical functions.
Solution Approach 2:
Multiple floor track grippers are merged into a single integrated assembly that is secured by a single locking pin. Instead of having separate locking mechanisms for each gripper, the invention combines them into one unified locking system where the locking pin passes through all grippers, creating a consolidated structure that improves reliability while minimizing the number of individual components.
3Ease of operation
If the locking pin is bent or dislodged, then the ease of operation improves (seat can be removed), but the reliability deteriorates (seat breaks away during emergency)
Solution Approach 1:
The locking mechanism is designed with preliminary action features that allow controlled disengagement. The locking pin can be deliberately retracted or disengaged through a controlled mechanism before flight operations, enabling easy seat removal when needed. However, during normal operation and emergency conditions, the preliminary positioning and multiple shear plane design ensure the pin remains securely engaged, preventing accidental dislodgment while maintaining ease of controlled removal.
Data Source
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AI summary
A double-shear secured vehicle seating assembly includes an operator seat (e.g., for a pilot or operator of a rotorcraft or like vehicle) and a seat frame structure via which the operator seat is secured to floor tracks in the cabin floor. Floor track grippers attached to the underside of the seat frame structure "grip" the floor tracks by extending down and around an upper portion of the floor track (110). The floor track grippers are further united with the floor tracks by locking pins that extend through holes in the grippers as well as the floor track (110) itself, which includes a rail and a plurality of evenly spaced holes extending through the rail. The locking pin (108) fully pierces the floor track gripper (106) on a first side, fully piercing the aligned hole in the rail, and at least partially piercing the floor track gripper (106) on the opposing side, creating the double-shear condition.