Vehicle Head Restraint with Friction Spring Adjustment
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Solution Overview
Problem
Existing vehicle head restraints that are vertically adjustable often require cumbersome manual adjustment, which can be difficult for users due to inconsistent effort requirements caused by thermal changes and design flaws.
Innovation Solution
A head restraint assembly with a base portion, a housing comprising a front and rear shell, a lock slide that moves between locked and unlocked conditions to allow vertical adjustment, and armature biasing members and journal friction springs to maintain consistent manual adjustment effort and prevent rattling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual adjustment mechanism is used for vertical head restraint adjustment, then the head restraint can be positioned vertically, but the adjustment becomes cumbersome and requires inconsistent effort
Solution Approach 1:
The patent applies dynamics by making the adjustment mechanism adaptive to changing conditions. The friction element's coefficient of friction varies dynamically with temperature and wear, allowing the mechanism to self-adjust to thermal expansion and wear without requiring manual recalibration. This resolves the contradiction by making the mechanism easier to operate consistently across different conditions while maintaining acceptable complexity.
Solution Approach 2:
The patent changes the friction parameter dynamically through the relationship between the friction element and the adjustment mechanism. As temperature changes cause thermal expansion, the friction element's engagement characteristics change, automatically compensating for dimensional changes. This allows consistent operation ease across temperature ranges without adding complex control systems.
2Reliability
If fixed friction characteristics are used in the adjustment mechanism, then the structure remains simple, but thermal changes cause inconsistent adjustment effort
Solution Approach 1:
The adjustment mechanism is designed to be self-compensating for thermal effects. The friction element automatically adjusts its engagement characteristics in response to temperature changes and wear, eliminating the need for external calibration or adjustment mechanisms. This achieves reliable consistent effort without adding complex control systems.
Solution Approach 2:
The friction characteristics are made dynamic rather than fixed, allowing the mechanism to adapt to thermal expansion and wear automatically. The friction element's effective friction coefficient changes with operating conditions, providing consistent adjustment effort across temperature ranges while maintaining a relatively simple structure.
3Ease of operation
If the head restraint allows free vertical movement, then adjustment is easy, but the head restraint becomes unstable and produces rattling sounds
Solution Approach 1:
The locking mechanism uses dynamic friction engagement where the friction element can be easily overcome during adjustment but automatically engages to lock the position once adjustment force is removed. This provides both easy adjustment operation and stable locked position, preventing rattling while maintaining ease of operation.
Solution Approach 2:
The friction element acts as an intermediary between the adjustment mechanism and the locking function. During adjustment, the friction element allows movement when sufficient force is applied; during normal operation, it maintains friction engagement to prevent movement and eliminate rattling sounds.
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 easy and consistent vertical adjustment of the head restraint with minimal effort, maintaining constant engagement and reducing undesirable sounds, while adapting to different designs and ambient conditions.
Implementation Method 1
at least one journal friction spring disposed within at least one of the front shell and the rear shell to control a manual adjustment effort
Implementation Method 2
at least one armature biasing member surrounding a portion of the base portion and biasing the base portion to be in constant contact with the front shell
Data Source
AI summary
A head restraint assembly includes a base portion including a first post portion extending in a vertical direction. Also included is a head restraint operatively coupled to the base portion. Further included is a housing comprising a front shell and a rear shell. Yet further included is a lock slide manually moveable between a locked condition and an unlocked condition. Also included is at least one armature biasing member surrounding a portion of the base portion and biasing the base portion to be in constant contact with the front shell. Further included is at least one journal friction spring disposed within at least one of the front shell and the rear shell to control a manual adjustment effort, the at least one armature biasing member and the at least one journal friction spring biasing the housing in the same direction.