Vehicle Head Restraint Assembly With Single-Shaft Infinite Adjustment
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Solution Overview
Problem
Existing adjustable head restraint systems in vehicles face issues with binding due to tolerances and misalignments, limiting positional flexibility and requiring specific notches or detents for adjustment.
Innovation Solution
A head restraint assembly featuring a single guide shaft with torsion spring and spherical bushings, allowing for infinite adjustment without binding, and a lever mechanism for easy one-handed operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple guide members are used in existing head restraint systems, then structural support is provided, but binding occurs due to tolerances and misalignments limiting positional flexibility
Solution Approach 1:
The patent extracts and eliminates the problematic multiple guide members from the system, retaining only a single guide shaft. This removal of redundant components eliminates the source of binding caused by tolerances and misalignments between multiple guide members, while preserving the necessary structural support through the simplified single-shaft design.
Solution Approach 2:
The patent segments the guidance function from the support function. The single guide shaft provides precise linear guidance without binding, while separate structural components (head restraint housing, mounting bracket) provide the necessary structural support. This separation allows each component to optimize its specific function without the compromises required when multiple guide members attempt to provide both guidance and support.
2Adaptability or versatility
If notches or detents are used for adjustment, then specific positioning is achieved, but adjustment flexibility is limited to discrete positions
Solution Approach 1:
The patent transitions from a static discrete-position system (with notches and detents) to a dynamic continuous-adjustment system. The single guide shaft combined with a ratchet mechanism allows the head restraint to be positioned continuously at any point along the adjustment range, not just at predetermined discrete positions. This dynamic capability provides infinite adjustment flexibility while maintaining ease of operation through the ratchet's one-way locking feature.
3Ease of operation
If a simple translation mechanism is used, then ease of operation is improved, but binding due to tolerances occurs
Solution Approach 1:
The patent introduces a ratchet mechanism as an intermediary between the translation motion and the locking function. This intermediary component allows smooth continuous translation during adjustment while providing reliable positional locking when desired. The ratchet mechanism decouples the translation smoothness requirement from the locking reliability requirement, allowing each to be optimized independently without causing binding.
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 solution provides flexible, infinite adjustment of the head restraint in the fore and aft direction, eliminating binding issues and allowing for precise positioning without the need for specific notches or detents, enhancing user convenience and comfort.
Implementation Method 1
A torsion spring is oriented about the guide shaft, retained between the pair of bushings and sized to tighten about the guide shaft and lock to a position upon the guide shaft
Data Source
AI summary
A head restraint assembly is provided with a first guide member mounted proximate to a vehicle seat back. A second guide member is mounted to the first guide member for translation along the first guide member. A locking mechanism is mounted to the second guide member in cooperation with the first guide member for locking the second guide member relative to the first guide member. The first and second guide members are the only guide members to minimize binding. The locking mechanism includes a torsion spring connected to the first guide member and oriented about the second guide member for locking the second guide member relative to the first guide member. A lever is mounted to the torsion spring for unlocking the torsion spring.