Child Car Seat Headrest Track for Constant Harness Fit
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Solution Overview
Problem
Current car seats require substantial adjustments to the shoulder harness belt length as the headrest is adjusted, leading to potential interference with vehicle seats and increased costs due to the need for new seats as children grow, and existing adjustable headrests are not always easy to operate or maintain the correct harness belt length.
Innovation Solution
A car seat with a vertically adjustable headrest that moves along a curved track, using a guide member and fixed guide bar to maintain the harness belt length, ensuring proper fit and clearance without requiring significant belt length adjustments, and incorporating a durable, easy-to-assemble design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the head rest is adjusted vertically to accommodate growing children, then the adaptability is improved, but the harness belt length changes requiring substantial adjustment
Solution Approach 1:
The head rest moves along a curved track rather than a linear path. This curved trajectory is designed to maintain a substantially constant distance between the head rest and the harness belt routing point, preventing significant changes in harness belt length during vertical adjustment
Solution Approach 2:
A curved guide track serves as an intermediary mechanism between the linear vertical adjustment requirement and the harness belt routing. The track geometry mediates the movement to maintain constant belt length while still allowing head rest position adjustment
2Adaptability or versatility
If the head rest is moved upward to fit taller children, then the adaptability is improved, but interference with the vehicle seat increases
Solution Approach 1:
The curved track design causes the head rest to move inward (toward the vehicle seat) as it rises vertically. This curved path reduces the horizontal clearance issue compared to linear vertical movement, minimizing interference with the vehicle seat while maintaining upward adjustability
3Ease of manufacture
If a linear track is used for head rest adjustment, then the ease of manufacture is improved, but interference with the vehicle seat increases
Solution Approach 1:
The track is formed with a curved profile that can be integrated into the seat back structure. The curvature is designed to provide both the necessary head rest movement path and adequate clearance from the vehicle seat, balancing manufacturability with interference prevention
Data Source
AI summary
A car seat includes a vertically adjustable head rest and harness support apparatus that will properly locate the position of the harness relative to the child in response to the positioning of the head rest. The head rest is movable along a curved track to provide horizontal clearance with respect to the vehicle head rest when in a fully raised position. The harness belt is trapped in a length adjustment lock and follows a path that extends around a fixed guide bar at the top of the car seat frame then downwardly through a guide member that directs the belt through an opening in the seat back for engagement with the child. The guide member is supported on a harness control tube that engages a rack device to fix the position of the harness control tube when the position of the head rest is selected.