Ratchet Headrest Mechanism for Precise Multi-Position Adjustment
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Solution Overview
Problem
Existing vehicle headrests lack a reliable mechanism for controlled, multi-position manual adjustment that allows for precise positioning and easy return to the initial design position, often requiring complex mechanisms or limited incremental adjustments.
Innovation Solution
A multi-position manually adjustable headrest featuring a ratchet defined support bracket with a pivotally secured, three-dimensional intermediate component and a biased locking pawl that engages selected ratchet locations, allowing for controlled incremental adjustments and automatic return to the initial position through a combination of arcuate channels, upwardly ramped ratchet portions, and a biasing clock spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a ratchet mechanism with locking pawl is used for incremental adjustment, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The adjustment mechanism is segmented into discrete ratchet positions along the ramped portion, allowing the headrest to be positioned at specific incremental intervals. The locking pawl engages with individual ratchet teeth to secure each position, providing precise positioning without requiring continuous adjustment controls.
Solution Approach 2:
The locking pawl is spring-biased to automatically engage with ratchet teeth as the headrest is moved to different positions. This self-acting mechanism eliminates the need for separate locking controls or complex actuation systems, achieving positioning precision through a simple, self-service design.
2Ease of operation
If a manual adjustment mechanism is used, then ease of operation is improved, but adjustment control precision deteriorates
Solution Approach 1:
The headrest adjustment mechanism allows dynamic movement through the ratchet positions during manual operation. The locking pawl engages and disengages naturally as the headrest is moved forward or backward, providing both ease of manual operation and precise positioning control through the incremental ratchet structure.
Solution Approach 2:
The ratchet teeth serve as an intermediary mechanism between the manual adjustment force and the final headrest position. As the user applies force to move the headrest, the ratchet teeth mediate the motion by allowing incremental displacement while preventing backward movement, thus achieving both ease of operation and positioning precision.
3Adaptability or versatility
If multiple adjustment positions are provided, then adaptability is improved, but device complexity increases
Solution Approach 1:
Multiple adjustment positions are achieved by extending the ratchet mechanism along a ramped portion in the vertical dimension. The locking pawl can engage with ratchet teeth at different heights along the ramp, providing multiple adjustment positions without requiring complex multi-axis mechanisms, thus maintaining simplicity while improving adaptability.
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
Enables precise, controlled incremental adjustments between multiple positions and effortless return to the initial design position, enhancing user convenience and durability by guiding pin-supported rivets along arcuate channels and utilizing a locking pawl mechanism that engages and disengages with the ratchet portions.
Implementation Method 1
A biasing clock spring is supported about a pin support and includes a first end abutting an edge of a central mounted portion associated with the support bracket and a second end biasing against a lower rim edge location of the three dimensional component.
Implementation Method 2
The locking pawl mechanism that engages and disengages with the ratchet portions
Data Source
AI summary
A multi-position and manually adjustable headrest having a support bracket affixed atop a seat back and exhibiting a plurality of ratchet defined portions. An intermediate and three dimensional shaped component is pivotally secured in a biased fashion to the ratchet defined bracket, the intermediate component exhibiting a pivotally supported and biased locking pawl which, depending upon a pivotal location of the intermediate component, engages a selected ratchet portion of said support bracket. A pair of headrest bun supporting plates are pivotally secured at upper ends to spaced apart sides of the intermediate pivotal component, the supporting plates further exhibiting lower arcuate extending channels through which seats pin supports projecting laterally from opposite sides of the ratchet support bracket and travel along the channels during forward displacement of the bun supporting plates, such as resulting from a manual readjustment force applied to a headrest bun. Concurrent rotation of the intermediate component in a controlled fashion occurring relative to its upper pivotal connection to the support plates and lower pivotal connection to the ratchet support bracket such that the pivotally supported locking pawl engages a selected ratchet portion of the support bracket between an initial position and at least one succeeding forward adjustment position.