Headrest X-Linkage Design for Adjustable Front-Rear Positioning
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Solution Overview
Problem
Existing headrests cannot be shifted to desired positions in the front-rear direction in a normal mode, limiting comfort and adjustability.
Innovation Solution
A headrest design featuring first and second headrest pillars, a stationary unit, a movable unit, an X linkage, and a front-rear locking mechanism with lock receivers and locking components that allow the movable unit to adjustably move relative to the stationary unit, enabling multiple positions in the front-rear direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the movable unit is designed to move only upon rear-end collision (using X linkage with solenoid unlocking), then the headrest provides sufficient strength and safety, but the headrest cannot be shifted to desired positions in the front-rear direction in normal mode
Solution Approach 1:
The locking mechanism transitions from a static collision-only unlocking system to a dynamic system that allows both normal manual adjustment and collision-based automatic unlocking. The movable unit can be freely adjusted by the user through the X linkage mechanism, and the locking mechanism responds dynamically to either manual operation or collision forces appropriately.
Solution Approach 2:
The system allows the user to self-adjust the headrest position through normal operation of the X linkage mechanism. The locking mechanism automatically engages when the user stops adjusting, eliminating the need for separate locking operations. In case of collision, the system automatically unlocks without user intervention.
2Adaptability or versatility
If a locking mechanism is added to enable multiple position adjustment, then the headrest provides enhanced comfort and adjustability, but the structure becomes more complex
Solution Approach 1:
The locking mechanism serves multiple functions: it enables normal manual position adjustment, maintains locked positions to prevent accidental movement, and automatically unlocks during rear-end collisions. The X linkage mechanism itself serves dual purposes as both the adjustment mechanism and the structural support element.
Solution Approach 2:
The locking mechanism is integrated with the existing X linkage structure rather than being a separate independent system. The lock receiver and locking component are positioned to work within the existing linkage geometry, combining the adjustment and locking functions into a unified system that shares common structural elements.
3Reliability
If the lock receiver protrudes rearward from the stationary unit, then the locking mechanism can engage properly, but the stationary unit may block the rotation of the lock receiver
Solution Approach 1:
The stationary unit is designed with a through-hole that segments the lock receiver's path of motion, allowing the lock receiver to protrude rearward for reliable engagement while passing through the clearance to avoid blocking. The through-hole creates distinct zones: a forward engagement zone for reliable locking and a rearward clearance zone for unobstructed rotation.
Solution Approach 2:
The through-hole in the stationary unit acts as an intermediary element that mediates between the conflicting requirements of lock receiver protrusion and rotation. It provides a defined passage that guides the lock receiver's motion, ensuring reliable engagement when needed while allowing free rotation when adjusting position.
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 headrest provides high seating comfort by allowing the movable unit to be shifted and locked at various positions, ensuring proper alignment with the occupant's head, and facilitating easy operation through a synchronized locking mechanism.
Implementation Method 1
an X linkage connecting the stationary unit to the movable unit, the X linkage including an inside linkage segment and an outside linkage segment rotatably connected each other at a central connecting intersection
Implementation Method 2
a spring arrangement biases the linkage or the housing respectively towards the extended position
Implementation Method 3
releasable locking means which lock the housing or the linkage, respectively in the basic position
Data Source
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AI summary
The purpose of the present invention is to provide a head rest in which the position of a movable member can be adjusted in stages forwards and backwards during normal operation. This head rest (1) is provided with a first and second head rest pillar (2a, 2b), a fixed member (4) provided between the first and second head rest pillars (2a, 2b), a movable member (5) which can move in the direction forwards away from or backwards returning towards the fixed member (4), an X-link mechanism which links the fixed member (4) and the movable member (5) and which has an inside link (6) and an outside link (7) rotatably connected through a cross connection unit (8) in the center, and a forward-backward lock mechanism which comprises an engaged unit (15) and a locking member (16) for engaging said engaged unit (15) and which locks, and releases locking of, movement of the movable member (5) forwards and backwards relative to the fixed member (4).