Child Car Seat Head Rest Locking Mechanism for Crash Stability
Solution Overview
Problem
Existing child car seat head rest adjustment mechanisms fail to maintain a secure lock during severe crashes, allowing the head rest to move unintentionally due to lack of positive locking features, which is a safety concern.
Innovation Solution
A child car seat with a height-adjustable head rest and an innovative adjustment mechanism that includes a lock element, such as a bell crank with a lock tab, and an actuator with a blocking end, which secures the lock element in a locked condition, preventing vertical adjustment during crashes and allowing for adjustment when desired.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flex fingers are used for locking elements, then the head rest can be adjusted vertically, but the locking elements cannot remain securely locked during severe crashes due to lack of positive locking
Solution Approach 1:
The locking mechanism is divided into separate functional components: flex fingers for engagement, a locking rod for positive locking, and a cam mechanism for controlled release. This segmentation allows each component to perform its specific function optimally - flex fingers provide adjustment capability while the locking rod provides crash-worthy locking stability.
Solution Approach 2:
The locking rod acts as an intermediary element between the flex fingers and the rail holes. It transfers and secures the locking force, providing a positive mechanical lock that prevents unintended release during crashes while still allowing controlled adjustment when the cam mechanism is actuated.
2Device complexity
If no blocking feature is provided for locking elements, then the adjustment mechanism is simple, but the lock element can unintentionally disengage during heavy loads or acceleration
Solution Approach 1:
The blocking feature on the locking rod prevents unintended disengagement before it can occur during heavy loads or acceleration. This preliminary protective action counteracts the harmful effect of crash forces that would otherwise cause accidental release of the head rest.
3Adaptability or versatility
If a cam mechanism with spring is used for locking, then the lock can be released and re-engaged, but there is no positive blocking feature to prevent accidental disengagement
Solution Approach 1:
The patent merges the cam-release mechanism (for adaptability) with the blocking feature on the locking rod (for reliability). This combination allows the system to benefit from both the ease of release/re-engagement provided by the cam-spring mechanism and the accidental-disengagement prevention provided by the blocking feature.
Data Source
AI summary
A child car seat has a seat back with an upper end and a head rest coupled to the seat back near the upper end. The head rest is vertically adjustable along the seat back between a raised position and a lowered position. The car seat has an adjustment mechanism with an actuator and a lock element. The lock element is movable between a locked condition preventing vertical adjustment of the head rest and an unlocked condition permitting vertical adjustment of the head rest. The actuator is actuable to reconfigure the adjustment mechanism between a locked arrangement blocking the lock element in the locked condition, a released arrangement unblocking the lock element from the locked condition, and an unlocked arrangement whereby the lock element is in the unlocked condition.