Seatback Latch Assembly With Pressing Bar to Reduce Rattle

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Solution Overview

Problem

Existing latch assemblies in vehicles experience rattle noise due to the striker being fixed in one direction, leading to instability and noise during operation.

Innovation Solution

A latch assembly design featuring a hinge-coupled latch with a pressing bar and link unit, where the pressing bar is moved upward when the latch is rotated downward, providing dual-direction fixation of the striker and reducing rattle noise through a link unit and optional return springs for enhanced stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the striker is fixed only in one direction (from upward to downward) by the latch, then the latch structure is simple, but rattle noise occurs during operation

Engineering Contradiction:
Improvelatch structureVSAvoidrattle noise
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The latch assembly is divided into multiple functional components: the latch body with claw portion for one-directional engagement, and the pressing bar with link unit for bidirectional fixation. This segmentation allows each component to perform its specific function while collectively solving the rattle noise problem through coordinated action.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fixing mechanism is extended from one dimension (upward to downward only) to two dimensions by adding the pressing bar that can move in both upward and downward directions. The link unit enables the pressing bar to follow the latch's rotational movement while maintaining bidirectional contact with the striker, thereby eliminating rattle noise through multi-directional constraint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Force

If a latch assembly is designed to fix the striker in both directions, then the fixing force is increased, but the device complexity increases

Engineering Contradiction:
Improvefixing forceVSAvoidlatch structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The link unit merges the rotational movement of the latch with the linear movement of the pressing bar into a single coordinated mechanism. As the latch rotates, the link unit automatically translates this motion to move the pressing bar upward or downward, ensuring bidirectional fixation without requiring separate actuation mechanisms for each direction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The link unit is designed to automatically respond to the latch's rotational movement and consequently drive the pressing bar to engage or disengage from the striker in the appropriate direction. This self-service mechanism eliminates the need for additional control systems, maintaining relative structural simplicity while achieving bidirectional fixation.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If the pressing bar is added to provide bidirectional fixation, then the rattle noise is reduced, but the device complexity increases

Engineering Contradiction:
Improverattle noiseVSAvoidlatch structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The link unit serves as an intermediary mechanism that couples the latch's rotational motion with the pressing bar's linear motion. This intermediary component enables the pressing bar to be actuated passively by the latch's movement, reducing the need for independent control mechanisms and keeping the overall system relatively simple while achieving effective bidirectional fixation to eliminate rattle noise.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design increases the fixing force on the striker in both directions, significantly reducing rattle noise and enhancing operational stability.

Implementation Method 1

a first end of the return spring is coupled to the supporting plate portion and a second end of the return spring is coupled to the second link bar, and configured to apply an elastic restoring force upward to the pressing bar

Methodology Applied
Scientific EffectElastic restoring force: Elasticity

Implementation Method 2

a first end of the return spring is coupled to the latch bracket and a second end of the return spring is coupled to the latch, and configured to apply an elastic restoring force downward to the latch

Methodology Applied
Scientific EffectElastic restoring force: Elasticity

Implementation Method 3

a latch having a rear side portion hinge-coupled to the latch bracket

Methodology Applied
Scientific EffectHinge mechanism: Hinge

Implementation Method 4

when the latch is rotated downward

Methodology Applied
Scientific EffectRotational movement: Moment of Inertia

Data Source

PatentEP4442502B1Latch assembly
Publication Date: 2026.01.21 DAE CHANG SEAT CO LTD DONGTAN
  • EP4442502B1 patent drawingFigure 1
  • EP4442502B1 patent drawingFigure 2
  • EP4442502B1 patent drawingFigure 3

AI summary

Proposed is a latch assembly with reduced rattle noise. The latch assembly includes a latch bracket mounted on a seatback frame, and includes a latch (120) having a rear side portion hinge-coupled to the latch bracket, having a front side portion bent downward, and having an end portion provided with a claw portion (122). Furthermore, the latch assembly includes a cable (160) connected to an upper surface of the latch, a hinge bracket (130) coupled to the rear side portion of the latch, a pressing bar (140) horizontally positioned below the claw portion, and a link unit (150) connecting the hinge bracket and the pressing bar to each other, the link unit being connected to the latch bracket, and the link unit being configured such that the pressing bar is moved upward when the latch is rotated downward.