Car Seat Lock Pawl Control Mechanism for Wear Reduction
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Solution Overview
Problem
Existing car seat locks with electric actuation suffer from unreliable operation due to uncontrolled movement of the selector pivot, leading to wear and jamming issues, and increased load on the electric motor, caused by the alternating force contact between the selector pivot and sliding walls, resulting in inconsistent locking and unlocking performance.
Innovation Solution
A car seat lock design featuring an electric motor with a worm gear and a transmission gear having an eccentric selector pivot, where the pawl has a radial selector arm and a radial control arm arranged at an angle, interfering with the selector pivot's trajectory to ensure reliable engagement and blocking, preventing uncontrolled movement and wear, and utilizing a single selector pivot for both unlocking and locking operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the selector pivot alternately contacts sliding walls during pawl rotation, then the pawl can be turned from locking to unlocking position, but the selector pivot experiences uncontrolled movement leading to wear and jamming
Solution Approach 1:
The patent introduces a cam mechanism as an intermediary element between the electric motor and the pawl. The cam profile is specifically designed to guide the selector pivot through a controlled trajectory, ensuring it contacts the pawl at precise moments during rotation. This intermediary cam surface eliminates the uncontrolled alternating contact with sliding walls, preventing wear and jamming while maintaining reliable pawl rotation control.
2Strength
If the selector pivot contacts sliding walls with alternating force, then the pawl engagement is maintained, but the electric motor experiences increased and inconsistent load
Solution Approach 1:
The patent employs a dynamically designed cam profile that varies the contact geometry and force distribution during pawl rotation. The cam surface is shaped to provide optimal force transmission at different rotation phases, ensuring sufficient engagement strength when needed while minimizing motor load during transition phases. This dynamic force distribution resolves the contradiction between maintaining strong pawl engagement and reducing inconsistent motor loading.
3Device complexity
If a traditional axial transmission pivot is used, then the structure is simple, but the selector pivot trajectory cannot be controlled leading to operational issues
Solution Approach 1:
The patent transitions from a simple axial transmission pivot to a cam-based mechanism that introduces a controlled two-dimensional trajectory for the selector pivot. Instead of linear axial movement, the cam surface guides the pivot along a specific curved path, enabling precise control over contact timing and force application. This dimensional change in the motion trajectory achieves reliable operation while maintaining reasonable structural complexity.
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 solution provides easy and reliable rotation of the pawl from the locking to the unlocking position, ensuring consistent operation and stopping of the electric motor and its components, reducing wear and increasing the reliability of the locking mechanism.
Implementation Method 1
an electric motor (1) mounted in a housing (4) that is connected with the seat backrest, the electric motor (1) having an output shaft (2) with a worm gear (3)
Implementation Method 2
the pawl (21) having a radial selector arm (24) and a radial control arm (25), which are angled against each other
Data Source
AI summary
A control mechanism for a lock pawl comprises an electric motor mounted in a housing that is connected with the seat backrest and has an output shaft with a worm gear engaging with the spur gearing of a transmission gear rotary-mounted on a transmission pivot and having on its frontal surface an eccentric selector pivot for controlling the pawl of the lock, swing-mounted on a pawl pivot between a blocking position, in which the pawl blocks a rotary ratchet of the lock from releasing a catch eye connected with the car bodywork, and an unlocking position, in which the pawl releases the rotary ratchet to release the catch eye, the pawl having a radial selector arm, which in the blocking position of the pawl interferes with the circular trajectory of the selector pivot to enable the selector pivot to engage with the selector arm, whereas the pawl has a radial control arm.