Vehicle Headrest Hinge Friction Locking Mechanism
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Solution Overview
Problem
Existing headrests with adjustable wing elements are either overly complex in design, making them difficult to assemble, or lack effective mechanisms for secure adjustment between positions, failing to provide a satisfying locking mechanism for the occupant.
Innovation Solution
A headrest design featuring a hinge with a projection and bushing configuration that creates a friction locking functionality, allowing the wing element to be rotatably mounted and securely locked in position, with a cam mechanism that engages in a receptacle to prevent unwanted pivoting and provide a tactile feedback of being locked, while allowing reversible adjustment between two positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a friction locking mechanism is used to prevent unwanted pivoting, then reliability is improved, but the wing element becomes difficult to transfer between positions
Solution Approach 1:
The hinge mechanism dynamically transitions between two states: a latched state where the projection engages the receptacle for stable locking, and a transitional state where friction is reduced to enable easy transfer. The cam mechanism dynamically converts rotational motion into the engagement/disengagement of the projection with the receptacle, allowing the system to switch between high-friction locking and low-friction transfer modes.
Solution Approach 2:
The hinge operates through periodic cycles of latching and unlatching. During each cycle, the cam mechanism periodically brings the projection into engagement with the receptacle (latching phase) and then allows it to disengage (transfer phase). This periodic action creates alternating periods of high stability and easy movability, resolving the contradiction between reliable locking and easy transferability.
2Reliability
If a complex hinge mechanism with friction detent functionality is used, then reliability is improved, but device complexity increases
Solution Approach 1:
The invention merges multiple functions into a single integrated hinge mechanism. The cam mechanism, projection, and receptacle work together as one unified assembly to provide both the friction locking functionality and the latching mechanism. This consolidation reduces the number of separate components needed, simplifying the overall structure while maintaining reliable locking functionality.
Solution Approach 2:
The hinge mechanism serves multiple functions simultaneously: it provides friction-based resistance during transfer, creates a positive latch through projection-receptacle engagement, and enables easy reversal between positions. The cam mechanism universally handles both the friction control and the latching action, making the hinge a multi-functional component that reduces overall system complexity.
3Ease of operation
If the projection engages in the receptacle to provide tactile feedback, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The cam mechanism changes the geometric parameters of the engagement process. By using the cam's curved surface, the projection is guided through a controlled path into the receptacle, transforming a potentially precise but difficult alignment task into a more tolerant engagement process. The cam profile parameters are designed to provide gradual engagement, reducing the sensitivity to manufacturing variations while still delivering clear tactile feedback.
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 simplifies assembly, enhances user feedback on adjusted positions, and prevents unintended wing element movement, ensuring the wing elements are securely locked in place, providing improved handling and safety features.
Implementation Method 1
the hinge for forming a friction locking functionality a shaft with a projection and a bushing with a receptacle associated with the projection
Implementation Method 2
the projection engaging in the receptacle in a latching position... gives an occupant a feeling of being locked in
Data Source
Figure 1~2
Figure 3~4
AI summary
A headrest (1) for a vehicle is disclosed, said headrest (1) comprising a main element (2) on which a wing element (3) is mounted by means of a hinge (4) so as to be rotatable about a substantially vertical axis; in order to create a frictional locking function, the hinge (4) comprises a shaft (41) with a projection (43) as well as a bush (42) with a receptacle (44) that is associated with the projection (43); the shaft (41) is mounted in the bush (42), and in a locked position the projection (43) engages into the receptacle (44).