Seat Armrest Pawl-and-Sector Assembly for 2° Angle Adjustment
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Solution Overview
Problem
Existing pivotally adjustable seat armrest assemblies lack efficient incremental adjustability and structural reinforcement to support significant downward forces while maintaining angular adjustability.
Innovation Solution
The design incorporates a stack of sectors with offset teeth patterns and pivotally secured pawls, biased by arcuate leaf springs, allowing incremental angular adjustments of up to 2°, with a retraction mechanism enabling unified outward pivoting of pawls to accommodate varying loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single pawl and sector assembly is used, then the device complexity is reduced, but the incremental adjustability and load support capability are insufficient
Solution Approach 1:
The armrest assembly is divided into multiple independent pawls (first, second, and third pawls) stacked together, each capable of engaging with the sector independently. This segmentation allows each pawl to support a portion of the load while collectively providing enhanced load support capability and incremental adjustability through their stacked arrangement.
2Strength
If multiple stacked pawls are used, then the load support capability is improved, but the device complexity increases
Solution Approach 1:
Multiple pawls are merged into a compact stacked assembly where they share common mounting features and work together with a single sector. The pawls are positioned adjacent to one another with their engaging surfaces oriented to engage the same sector, creating a unified load-bearing structure that provides enhanced strength while maintaining a space-efficient design.
3Ease of operation
If the pawls are spring-biased for automatic engagement, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The pawls are equipped with springs that automatically bias them toward the sector, enabling automatic engagement when the armrest is moved to a new position. The springs continuously apply force to keep the pawls in contact with the sector teeth, eliminating the need for manual intervention to maintain engagement and providing self-locking capability throughout the adjustment range.
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 provides enhanced load support and incremental adjustability, maintaining a holding force of up to 220 lbs, while allowing for easy angular adjustments and structural reinforcement through consistent or offset teeth patterns across the sectors.
Implementation Method 1
A plurality of arcuate leaf springs may be secured to the armrest support and in order to bias the pawls towards the sector stack
Implementation Method 2
The sectors exhibit an array of teeth exhibiting first angular offset or increment compared to that associated with the stacked pawls... to provide 2° incremental adjustability
Data Source
AI summary
An incrementally adjustable armrest associated with a seatback having an armrest supported in pivotal fashion to a frame location of the seatback. At least one sector is fixed to the seatback frame and supports a pivotal location associated with the armrest. A plurality of teeth are located along a circumferential edge extending location of the sector corresponding to a range of adjustment associated with the armrest. A plurality of pawls are arranged in a stacked relationship and are pivotally secured to the armrest at a location such that additional teeth associated with the pawls are biased in an engaging direction against the sector. A teethed pattern associated with a selected pawl individually seats within a circumferential location associated with the sector teeth.