Radial Pawl Track Locking for Precise Seat Positioning
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Solution Overview
Problem
Existing seat position locking mechanisms for aircraft seats are heavy, costly, and prone to free play during engagement, leading to imprecise adjustments, unwanted vibrations, rattling noise, and potential back drive, which can cause damage and require strong springs that are difficult to operate.
Innovation Solution
A lock mechanism using a radial pawl with convex and concave serrations, a motion-translation component, and a spring system to control the angular motion of the pawl, allowing for precise locking and unlocking with reduced spring force, minimizing weight and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two teethed locking chucks are used to restrict movement in each direction, then the locking mechanism can prevent back drive, but the weight and manufacturing cost increase
Solution Approach 1:
The patent combines two separate locking chucks into a single radial pawl that can engage with serrations on both sides of the track tube. This merging of functions allows one component to perform the work of two, reducing weight while maintaining the ability to prevent back drive in both directions.
Solution Approach 2:
The radial pawl is designed as a universal locking component that can restrict movement in multiple directions by engaging with convex-curved serrations positioned on opposite sides of the track tube. This multi-functional design eliminates the need for direction-specific locking chucks.
2Device complexity
If linear motion locking mechanism with wedging force is used, then the structure is simple, but free play occurs during engagement leading to imprecise positioning
Solution Approach 1:
The patent employs convex-curved serrations and a radially-pivoting pawl that engages with these curved features. The curved geometry eliminates free play by ensuring continuous contact between the pawl and track serrations during engagement, providing precise positioning while maintaining mechanical simplicity.
3Reliability
If strong spring force is applied to prevent back drive, then engagement reliability improves, but the force required by user to disengage increases
Solution Approach 1:
The radial pawl is designed to pivot dynamically in response to applied loads. During normal operation, the pawl maintains engagement with minimal spring force. During disengagement, the user applies force that causes the pawl to pivot and ride over the serrations, allowing easy operation without requiring the user to overcome strong spring forces.
Solution Approach 2:
The geometry of the convex-curved serrations and radial pawl arrangement creates a mechanical advantage where the engagement force is amplified by the curved contact surfaces. This preliminary geometric design reduces the spring force needed to maintain engagement while preserving easy disengagement through user-applied force.
4Reliability
If strong spring force is used to keep teeth engaged, then back drive is prevented, but safety hazard increases due to strong pinch points
Solution Approach 1:
The dynamic radial pawl design allows the engagement force to be applied through the pivoting mechanism rather than through strong springs. The pawl naturally maintains contact with the track serrations through its geometric arrangement, eliminating the need for high spring forces that create dangerous pinch points while still preventing back drive.
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 mechanism provides precise seat position adjustments with reduced spring force, minimizing vibrations and noise, and preventing back drive, while being easier to operate and safer for users, especially those with weaker hands.
Implementation Method 1
the radial pawl has a pivot point... control a rate of angular motion of the radial pawl pivoting about the pivot point
Implementation Method 2
the spring force applied on the locking mechanism to keep teeth of the locking chuck engaged with teeth on the track
Implementation Method 3
the slot is configured to at least partially constrain motion of the pin such that a pivotal motion of the motion-translation component about the track axis is translated to a slider motion of the pin by the slot to control a rate of angular motion
Implementation Method 4
the set of concave-curved serrations is configured to engage with the set of convex-curved serrations of the track tube to lock a position of the track tube along the track axis
Data Source
AI summary
An embodiment position locking apparatus includes a track tube, convex-curved serrations in the track tube, a radial pawl, a pin, concave-curved serrations in the radial pawl, and a motion-translation component. The radial pawl may have a pivot point and the pin extending from the radial pawl. The motion-translation component may have a slot formed therein and disposed adjacent the radial pawl. The pin may extend into the slot so the slot at least partially constrains motion of the pin such that a pivotal motion of the motion-translation component is translated to a slider motion of the pin to control a rate of angular motion of the radial pawl pivoting about the pivot point and so the concave-curved serrations engage and disengage with the convex-curved serrations to lock and unlock a position of the track tube relative to the radial pawl.