Ratcheting Headrest Assembly With Multi-Position Pawl Spring Locking
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Solution Overview
Problem
Existing headrest assemblies for vehicles lack a compact and cost-effective mechanism to efficiently adjust the head restraint from an upright position to an inclined position and back, with limited control over multiple locked positions.
Innovation Solution
A ratcheting headrest assembly featuring a pawl and pawl spring with distinct sections, a cam with multiple teeth, and a pawl that engages and disengages to lock and unlock positions, allowing the head restraint to rotate from an upright to an inclined position and back, utilizing a ratchet assembly with a pawl and pawl spring to manage the movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional headrest adjustment mechanism is used, then the structure is simple, but it lacks multiple locked positions and control over inclined positions
Solution Approach 1:
The pawl spring is divided into two distinct sections: a first section that contacts the pawl during normal rotation from upright to inclined position, and a second section that contacts the pawl when rotation exceeds the inclined position. This segmentation allows the single ratchet assembly to provide multiple locked positions (upright, inclined, and forced upright) without adding complex additional mechanisms.
Solution Approach 2:
The ratchet assembly with the two-section pawl spring serves multiple functions: it allows controlled rotation to inclined position, provides locked positioning at multiple angles, and enables forced return to upright position when rotation exceeds the limit. This multi-functionality achieves adaptability without proportionally increasing device complexity.
2Ease of manufacture
If a compact mechanism is used, then manufacturing cost is reduced, but control over multiple positions may be limited
Solution Approach 1:
The patent merges the functions of multiple position control mechanisms into a single ratchet assembly with a two-section pawl spring. Instead of using separate mechanisms for upright positioning and inclined positioning, both functions are integrated into one assembly, simplifying manufacturing while maintaining full position control capability.
Solution Approach 2:
The pawl spring transitions from a single-plane structure to a multi-plane structure where the first and second sections lie in different planes. This dimensional change allows the spring to contact the pawl at different positions and angles, enabling control over multiple locked positions within the compact ratchet assembly structure.
3Adaptability or versatility
If the head restraint can rotate freely, then adjustment flexibility is improved, but uncontrolled rotation beyond locked positions occurs
Solution Approach 1:
The ratchet assembly is designed with predetermined locked positions (upright and inclined) that prevent uncontrolled rotation. The pawl spring is pre-configured with two sections that will engage the pawl at specific rotation angles, providing preliminary resistance against excessive rotation before the user even attempts to rotate beyond the locked positions.
Solution Approach 2:
The two-section pawl spring provides mechanical feedback to the user during rotation. When the head restraint reaches a locked position, the corresponding pawl spring section engages the pawl, creating a tactile sensation that indicates the locked position. This feedback ensures reliable positioning while maintaining rotation flexibility within the designed 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
The solution provides a compact, cost-effective, and easily assembled mechanism that allows for multiple locked positions of the head restraint, enhancing user control and reducing manufacturing complexity while ensuring efficient adjustment between upright and inclined positions.
Implementation Method 1
the pawl spring includes a first section and a second section. The first section of the pawl spring is configured to contact the pawl when the head restraint is rotated from the first locked position to the second locked position, and the second section of the pawl spring is configured to contact the pawl when the head restraint is rotated beyond the second locked position
Data Source
AI summary
A headrest assembly according to an exemplary aspect of the present disclosure includes a head restraint configured to rotate from a first locked position to a second locked position to incline the head restraint relative to a seat back. Further, the head restraint is configured such that rotation of the head restraint beyond the second locked position causes the head restraint to become urged back to the first locked position. The head restraint includes a ratchet assembly having a pawl and pawl spring, and the pawl spring includes a first section and a second section. The first section of the pawl spring is configured to contact the pawl when the head restraint is rotated from the first locked position to the second locked position, and the second section of the pawl spring is configured to contact the pawl when the head restraint is rotated beyond the second locked position.