Vehicle Seat Locking Hook Dynamics and Tolerance Compensation

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Solution Overview

Problem

Existing vehicle seat locking devices lack improved safety, comfort, and manufacturability, particularly in compensating for tolerances and ensuring a secure fit between the locking hook and bolt.

Innovation Solution

A locking device with a locking hook that performs both translatory and rotary movements, utilizing a sleeve and slot combination, a spring mechanism for biasing towards the locking position, and a tensioning eccentric to enhance engagement with the bolt, along with a receiving lever and actuating means for controlled locking and unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the locking hook performs only a rotary movement, then the structure is simpler, but the tolerance compensation and positive fit with the bolt are insufficient

Engineering Contradiction:
Improvepositive fit between locking hook and boltVSAvoidlocking hook movement mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The locking hook is designed to perform both translatory and rotary movements during engagement, transforming a static single-degree-of-freedom mechanism into a dynamic two-degree-of-freedom system. This dynamic movement pattern enables the locking hook to adapt to tolerance variations in the bolt positioning while maintaining secure engagement, directly resolving the contradiction between manufacturing precision and structural simplicity.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the tensioning means engages early, then the locking force is applied sooner, but the ratchet may not be properly positioned for engagement with the bolt

Engineering Contradiction:
Improvelocking engagement reliabilityVSAvoidtiming of locking force application
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The mechanism is designed so that the ratchet is preliminarily positioned in the correct engagement position with the bolt before the tensioning means applies the locking force. This preliminary positioning ensures that when the tensioning force is applied, the ratchet is already properly aligned, preventing misengagement while maintaining efficient locking action.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The mechanism incorporates a feedback sequence where the translatory movement of the locking hook triggers the ratchet positioning, which in turn enables the tensioning means to engage at the optimal moment. This feedback loop ensures that each component acts in the correct sequence, with the tensioning force applied only after proper positioning is confirmed.

Inventive Principle:
Principle #23Feedback

3Reliability

If the spring means provides strong biasing force, then the locking hook engages the bolt more reliably, but the unlocking operation requires more force

Engineering Contradiction:
Improvelocking engagement reliabilityVSAvoidunlocking operation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The spring means is designed to provide strong biasing force during the locking phase to ensure reliable engagement, but the unlocking mechanism utilizes the dynamic movement sequence where the actuating means first moves the locking hook translationally to disengage the ratchet before the spring force acts on the locking hook. This dynamic sequencing allows strong locking force during engagement while maintaining ease of operation during unlocking.

Inventive Principle:
Principle #15Dynamics

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 a secure, adaptable, and efficient locking mechanism that compensates for tolerances and improves the positive fit between the locking hook and bolt, enhancing safety and comfort while simplifying manufacturability.

Implementation Method 1

the locking device has a spring means which rotationally and translationally biases the locking hook towards its locking position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a spring means, in particular a torsion spring, one limb of which rests on the tensioning means and the other limb of which rests on the receiving lever

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP3022081B1Locking device
Publication Date: 2019.12.04 ADIENT LUXEMBOURG HLDG SARL
  • EP3022081B1 patent drawingFigure 1~2c
  • EP3022081B1 patent drawingFigure 2d~3

AI summary

The invention relates to a locking device for a vehicle seat, for locking the back rest to a seat part and/or the body of the vehicle using a locking lever which can be moved from an unlocked position into a locked position in which it lockingly interacts with a bolt.