Vehicle Head Restraint Locking Device with Friction and Positive Segmentation
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Solution Overview
Problem
Existing locking devices for vehicle head restraints often produce noise and increase wear during adjustment, and may not provide optimal safety in accident scenarios due to inadequate locking mechanisms.
Innovation Solution
A locking device with a combination of blocking and sliding mechanisms, utilizing oblique surfaces and springs to facilitate smooth, noise-reduced adjustments while ensuring safety, featuring predominantly frictional and positive locking means that engage based on load conditions, and incorporating a blocking pin for enhanced security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bolt and toothed portion are used for locking with positive engagement, then reliable locking is achieved, but noise is generated during adjustment and wear increases
Solution Approach 1:
The locking mechanism is segmented into two distinct subsystems: a frictional locking means for normal operation and a positive locking means for secure positioning. This segmentation allows each subsystem to perform its specialized function optimally - the frictional mechanism provides smooth, quiet adjustment while the positive mechanism ensures reliable locking without noise during adjustment
Solution Approach 2:
The locking mechanism transitions dynamically between two states based on operational requirements. During normal adjustment, the frictional locking engages to allow controlled movement. When secure positioning is needed, the positive locking engages to prevent movement. This dynamic switching resolves the contradiction by providing both smooth adjustment and reliable locking without the harmful effects of each other
2Ease of operation
If the bolt is lifted counter to spring force for release, then adjustment is enabled, but increased wear occurs on the bolt and toothed portion
Solution Approach 1:
The traditional mechanical lifting mechanism is replaced with a friction-based release system. Instead of lifting the bolt against spring force, the user simply overcomes the frictional resistance by applying force in the adjustment direction. This substitution eliminates the wear-causing lifting action while maintaining ease of operation
Solution Approach 2:
The locking mechanism changes the friction parameter dynamically - during normal operation, friction provides stable positioning; during adjustment, the friction is overcome by applied force. This parameter change allows easy adjustment without the wear associated with traditional spring-loaded lifting mechanisms
3Object-generated harmful factors
If predominantly frictional locking is used for smooth adjustment, then noise is reduced, but locking reliability under high load decreases
Solution Approach 1:
The locking system is divided into two functional segments: a frictional locking means for noise-free adjustment and a positive locking means for load-bearing security. This segmentation allows the frictional component to handle low-load adjustment operations quietly while the positive locking component handles high-load scenarios reliably
Solution Approach 2:
The system dynamically switches between frictional and positive locking modes based on load conditions. Under normal operating loads, the frictional locking provides smooth, quiet operation. When loads exceed a certain threshold, the positive locking mechanism engages to maintain reliability, thus resolving the contradiction between noise reduction and locking reliability
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 robust, reliable mechanism for adjusting head restraints with reduced noise and increased safety, ensuring secure positioning and comfort adjustments without excessive wear, and effectively engages locking mechanisms only under necessary loads.
Implementation Method 1
a spring (41) arranged between the first subsection (11) and the second subsection (12) in the direction of displacement C, which is acting on the first subsection (11) with a force in the direction of displacement C
Implementation Method 2
the locking device comprises both predominantly positive and predominantly frictional locking means, for example the locking at base load or a lower operating load taking place predominantly frictionally and with an increased operating load predominantly positively
Data Source
AI summary
A locking device is disclosed, such as for head restraint of a vehicle seat. The head restraint has a first subsection that may be displaced from a first position in a direction of displacement into a comfort position. Relative movement of a second subsection relative to the first subsection and/or relative to a third subsection is provided about a rotational axis substantially parallel to the direction of displacement. A blocking device and a sliding device are arranged between the first and second subsections and/or between the second and third subsections.