Vehicle Seat Longitudinal Adjuster Crash Locking Mechanism
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Solution Overview
Problem
Existing longitudinal seat adjusters for vehicles are inadequate in withstanding high forces during crashes, leading to potential detachment of the seat from the vehicle structure and increased risk of injury from sudden braking.
Innovation Solution
Incorporation of an additional crash-sensitive locking mechanism actuated by mass inertia, which is normally inactive but engages during a crash to enhance load absorption without damaging the locking device, featuring a pivot lever, latching element, and a freely movable metal sphere to lock the seat rails in both front and rear impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the longitudinal adjuster is designed to withstand normal loads during regular use, then the locking device can be kept simple and lightweight, but it cannot withstand high forces during crashes
Solution Approach 1:
The locking system is divided into two independent segments: a primary locking device for normal use and an additional crash-sensitive locking means. The additional locking means comprises a housing, pivot lever, and sphere that operate independently from the primary locking device, allowing each segment to be optimized for its specific function without compromising the other.
Solution Approach 2:
The additional locking means transitions from an inactive state during normal operation to an active locked state during crashes. The sphere is freely movable within the housing and only engages with the pivot lever when subjected to crash forces, enabling the system to adapt its locking capacity dynamically based on the operational conditions.
2Reliability
If the locking device is strengthened to withstand crash forces, then safety during crashes improves, but the risk of damage or impairment to the locking device increases
Solution Approach 1:
The additional locking means is pre-positioned and pre-configured within the housing to engage automatically when crash forces are applied. The sphere is freely movable and ready to pivot the lever into the locked position before the actual crash impact occurs, cushioning the locking device from the full force of the crash by engaging the additional locking mechanism in advance.
Solution Approach 2:
The sphere acts as an intermediary element that translates crash forces into the activation of the pivot lever. Rather than the crash force directly acting on the locking device, the sphere mediates by pivoting the lever to engage the latching element, distributing and managing the crash forces through a controlled mechanical action.
3Strength
If an additional crash-sensitive locking means is added, then load absorption during crashes increases, but the device complexity and number of components increases
Solution Approach 1:
The additional locking means combines multiple functions into a compact assembly: the housing provides structural support and guidance, the pivot lever provides the locking action, and the sphere provides the crash-sensitivity mechanism. These components are merged into a single integrated unit that can be added to the existing longitudinal adjuster without requiring separate systems for each function.
Solution Approach 2:
The additional locking means is self-activating and requires no external control systems, actuators, or power sources. The crash forces directly cause the sphere to pivot the lever and engage the locking mechanism, allowing the system to service itself automatically during crashes without adding complex control electronics or additional actuation mechanisms.
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 additional locking mechanism effectively increases load absorption during crashes without impairing the locking device, ensuring the seat remains securely attached to the vehicle structure, reducing the risk of injury from sudden movements.
Implementation Method 1
an additional locking means which is normally inoperative and is actuated only in the event of a crash by mass inertia
Data Source
AI summary
A longitudinal adjuster (10) for a vehicle seat (1), including at least one rail pair which is formed from a first seat rail (12) and a second seat rail (14), the seat rails (12, 14) of the rail pair encompassing one another and being movable relative to one another in the longitudinal direction (x) and being able to be locked to one another via a locking device (16), the locking device (16) having at least one locking element, in particular at least one latching plate (18) which is movable in the vertical direction (z), the longitudinal adjuster (10) having an additional locking means (30) which is normally inoperative and is actuated only in the event of a crash by mass inertia. A vehicle seat (1), in particular a motor vehicle seat, includes a seat part (2) and a longitudinal adjuster (10).