Vehicle Seat Locking Mechanism That Prevents Self-Opening
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Solution Overview
Problem
Existing locking and releasing mechanisms for vehicle seats are prone to inadvertent opening under high loads, posing safety concerns, and require precise manufacturing and assembly, increasing production and assembly costs.
Innovation Solution
A locking and releasing mechanism featuring a detent pawl and detent plate that can be selectively locked and released using a drive means with a securing segment, which secures the detent plate against self-opening, allowing for optimized locking angles and easier release, while accommodating manufacturing tolerances without compromising strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism with pawl and detent plate is used to prevent inadvertent opening under high loads, then safety and reliability are improved, but the mechanism becomes more complex and requires finer tolerances which increases manufacturing and assembly costs
Solution Approach 1:
The locking mechanism is divided into functionally independent segments: the detent plate for positioning, the pawl for locking, and the securing segment for preventing self-opening. This segmentation allows each component to be optimized independently and simplifies manufacturing tolerances while maintaining reliability.
Solution Approach 2:
The securing segment acts as an intermediary element between the detent plate and the blocking member. It mediates the interaction by providing a positive locking interface that prevents the detent plate from moving in the unlocking direction under load, without requiring the entire mechanism to be overly complex.
2Reliability
If fine tolerances are used in the locking mechanism to prevent self-opening, then reliability is improved, but manufacturing and assembly costs increase
Solution Approach 1:
By segmenting the mechanism into distinct functional parts with clear interfaces, each part can be manufactured within standard tolerances. The securing segment's geometry is designed to provide functional locking without requiring precision fitting, thereby reducing manufacturing costs while maintaining reliability.
Solution Approach 2:
The design changes the geometric parameters of the securing segment and blocking member to create a self-locking geometry. This allows the mechanism to achieve reliable locking through its inherent geometry rather than relying on tight tolerance stacks, significantly easing manufacturing requirements.
3Ease of operation
If the detent plate is designed to be easily released, then ease of operation is improved, but the mechanism may become prone to self-opening under load
Solution Approach 1:
The release function is separated from the locking function by introducing a dedicated driver that acts only on the detent plate. The driver can easily move the detent plate in the release direction, while the securing segment independently prevents any load-induced movement in the unlocking direction, thus achieving both ease of operation and high reliability.
Solution Approach 2:
Instead of designing the detent plate to be inherently difficult to move and then providing a force to overcome this, the design inverts the approach: the detent plate is designed to move easily in both directions, but the securing segment is designed to allow movement only in the locking direction under load, while the driver provides controlled movement in the release direction.
Data Source
AI summary
A locking and releasing mechanism for a seat having a first fitting part associated with one of a seat part and a backrest and a second fitting part associated with the other one of the seat part and the backrest that may be locked and released relative to one another by the mechanism is disclosed. The mechanism includes a detent pawl configured to selectively latch the first fitting part to lock a displacement of the first fitting part and the second fitting part relative to one another and a detent plate configured to be reversibly displaced between a detent position, wherein the detent plate locks the detent pawl so that the detent pawl remains latched with the first fitting part, and a release position, wherein the detent plate allows the detent pawl to be released from the first fitting part. The mechanism also includes drive means configured to selectively move the detent plate between the detent position and the release position. The drive means includes a securing segment for securing the detent plate against self opening.