Recliner with a locking- and unlocking device having two independently adjustable locking mechanisms

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Solution Overview

Problem

Existing backrest adjustment devices for motor vehicle seats face challenges in securely locking and adjusting the backrest without play, especially under high forces, while maintaining precise control over the locking mechanisms.

Innovation Solution

A backrest fitting with a covering and unlocking device that employs a snail toothing and snail wheel mechanism, combined with radial and axial clamping elements, to securely lock the snail in place, allowing for precise adjustment and high-force absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single locking mechanism is used in existing backrest adjustment devices, then the device complexity is reduced, but the reliability of locking under high forces deteriorates

Engineering Contradiction:
Improvelocking reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is divided into two independent locking mechanisms (first locking mechanism with radial clamping element and second locking mechanism with axial clamping element) that act on the worm at different positions and directions. Each locking mechanism independently secures the worm, providing redundant locking capability that enhances reliability under high forces while maintaining manageable device complexity through modular design.

Inventive Principle:
Principle #1Segmentation

2Force

If radial and axial clamping elements are used to securely lock the worm, then the force absorption capability is improved, but the ease of operation deteriorates

Engineering Contradiction:
Improveforce absorptionVSAvoidadjustment operation
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The actuating elements of the first and second locking mechanisms are coupled together such that a single actuating operation simultaneously controls both the radial clamping element and the axial clamping element. This merging of control functions allows the dual-locking system to absorb high forces while maintaining ease of operation through unified actuation.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If two independently adjustable locking mechanisms are used, then the precision of position control is improved, but the device complexity increases

Engineering Contradiction:
Improveposition control precisionVSAvoidlocking device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The first locking mechanism with radial clamping element provides precision control in the radial direction, while the second locking mechanism with axial clamping element provides precision control in the axial direction. Each locking mechanism is optimized for its specific directional control function, achieving high position control precision while keeping each individual mechanism relatively simple in structure.

Inventive Principle:
Principle #3Local quality

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, play-free adjustment mechanism that can absorb high forces, ensuring precise control over the backrest's position and facilitating easy operation through a simple actuation mechanism.

Implementation Method 1

one of the fitting parts is assigned a worm with worm teeth and the other fitting part is assigned a worm wheel, wherein the worm teeth engage in the worm wheel

Methodology Applied
Scientific EffectWorm gear: Worm Drive

Implementation Method 2

the first locking mechanism acts on the worm in the locking position radially to the longitudinal extent of the worm and the second locking mechanism acts on the worm in the locking position axially in the longitudinal extent of the worm

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4214085B1Recliner with a locking- and unlocking device having two independently adjustable locking mechanisms
Publication Date: 2025.05.07 BROSE SITECH GMBH
  • EP4214085B1 patent drawingFigure 1
  • EP4214085B1 patent drawingFigure 2
  • EP4214085B1 patent drawingFigure 3

AI summary

The invention relates to a backrest adjustment fitting having a locking and unlocking device which locks two fitting parts (10, 20) of the backrest adjustment fitting in a locking position (I), wherein a worm screw (40) having worm gearing (41) is associated with one of the fitting parts (10, 20) and a worm wheel (11) is associated with the other fitting part (10, 20), wherein the worm gearing (41) meshes with the worm wheel (11). The locking and unlocking device has two locking mechanisms (50, 50R; 60, 60A), wherein the first locking mechanism (50, 50R), in the locking position (I), acts on the worm screw (40) radially with respect to the longitudinal extension (X) of the worm screw (40), and the other locking mechanism (60, 60A), in the locking position (I), acts on the worm screw axially in the longitudinal extension (X) of the worm screw (40), such that the worm screw (40) having worm gearing (41) is arranged so as to be doubly braced in the worm wheel (11).