Headrest Folding Device Ratchet Mechanism
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Solution Overview
Problem
Existing headrest folding devices face challenges with stiff operation, increased load on components, noise generation, and limited strength due to direct force transfer and exposure, which complicates smooth folding and locking mechanisms.
Innovation Solution
A headrest folding device incorporating a ratchet mechanism that indirectly transfers the operation from a release lever to a lock link, utilizing twisted coil springs and a mountain peak-shaped groove and ridge for smooth operation, reducing externally exposed area and enhancing strength without altering the stay's circular cross-section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the force applied to the stay rod is directly transferred to the holding member, then the holding member can maintain the erected position, but the rotation of the holding member becomes very stiff and difficult to operate
Solution Approach 1:
A ratchet mechanism is introduced as an intermediary between the stay rod and the release lever. The ratchet has teeth that engage with grooves on the stay rod, allowing force transfer while the release lever operates independently to disengage the ratchet, enabling smooth operation without directly moving the heavy holding member
Solution Approach 2:
The locking mechanism is divided into separate functional components: the ratchet for force transfer and locking, the release lever for operation, and the holding member for positioning. This segmentation allows each component to be optimized independently, with the release lever being lightweight and easy to operate while the holding member maintains strong holding capability
2Productivity
If the stopping member is directly pulled to release the holding member, then the headrest can be folded, but a large load is imposed on the stopping member and wire making operation difficult
Solution Approach 1:
The ratchet acts as a mediator that receives and distributes the force from the release lever to the stay rod and holding member system. This allows the wire and stopping member to be pulled with much less force since they only need to disengage the ratchet teeth rather than directly move the entire locking mechanism
Solution Approach 2:
The ratchet mechanism provides self-locking through its tooth engagement with the stay rod grooves. Once the holding member is released, the ratchet automatically engages with the next groove position, providing automatic re-locking without requiring additional force or complex control mechanisms
3Reliability
If the holding member directly holds the stay rod, then the locking function is achieved, but the structure requires more components and increased complexity
Solution Approach 1:
The ratchet and release lever are combined into a single integrated assembly where the release lever directly actuates the ratchet teeth. This merging reduces the number of separate components compared to having independent locking and releasing mechanisms, while maintaining reliable locking function through the tooth-groove engagement
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
Facilitates smooth and soft operation of the release lever, increases the headrest's strength, reduces the number of components, and minimizes the externally exposed area, while maintaining the appearance and functionality of the seat back.
Implementation Method 1
a first twisted coil spring whose one end is supported by the main bracket and the other end is supported by the horizontal bar of the stay
Implementation Method 2
a ratchet which is rotatably supported by the main bracket through a line shaft, and the contact of which with the lock link is released by the release lever
Data Source
AI summary
The present invention relates to a headrest folding device, more particularly, to a headrest folding device wherein a ratchet is connected between a release lever and a lock link which maintains the unfolding (upright) of a headrest, so that the operation of the release lever is not directly transferred to the lock link, but rather indirectly transferred to the lock link through the ratchet, thereby smoothing the operation of the release lever.