Seatback Folding Spring Layout for Safer Fold and Easier Unfold

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Solution Overview

Problem

Existing vehicle seatback folding devices face issues with high folding speed, which can cause injury to occupants, and high unfolding force, making it difficult to unfold the seatback.

Innovation Solution

A vehicle seatback folding device is designed with a cushion bracket and a back side frame hinged together, featuring a restoring spring and a reverse spring. The restoring spring assists in folding the seatback, while the reverse spring helps in unfolding it, reducing the required unfolding force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If only a restoring spring is used to fold the seatback, then the folding function is simple, but the folding speed becomes too high causing injury to occupants

Engineering Contradiction:

Improvefolding device structureVSAvoidfolding speed

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

The reverse spring applies a preliminary counteracting force during the folding process to oppose the restoring spring's force. This preliminary anti-action prevents the seatback from folding too quickly by continuously applying a counterbalancing force throughout the folding motion, thereby controlling the folding speed and preventing occupant injury.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system changes the force parameter dynamically during folding by switching between different spring configurations. Initially, both restoring and reverse springs are engaged to control speed; as folding progresses, the reverse spring disengages from the support end, allowing the restoring spring to complete the folding action. This parameter change enables controlled folding speed throughout the process.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If only a restoring spring is used, then the device is simple, but the unfolding force required is significantly large

Engineering Contradiction:

Improvespring mechanismVSAvoidunfolding force

Core Design Contradiction:

Device complexityVSForce

Solution Approach 1:

The reverse spring acts as an intermediary that provides assistance during the unfolding process. When the seatback needs to be unfolded, the reverse spring engages with the support end on the cushion bracket and applies a helping force in the unfolding direction, working together with the user's input force to reduce the overall unfolding force required.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The reverse spring functions as a counterweight mechanism during unfolding by providing an opposing force to the restoring spring's folding force. This counterbalancing effect reduces the net force the user must apply to unfold the seatback, making the operation easier while maintaining structural integrity.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Use of energy by moving object

If the seatback is folded forwards by its own weight, then no additional force is needed, but the high folding speed causes injury to occupants

Engineering Contradiction:

Improvegravitational energyVSAvoidinjury risk to occupants

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The reverse spring converts the harmful high-speed folding motion into a beneficial controlled motion. By engaging the reverse spring during folding, the system transforms the potentially injurious rapid movement into a controlled, slower motion that still achieves the folding function while preventing occupant injury. The spring's resistance becomes a safety feature rather than an obstacle.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 device reduces the folding speed and force after the seatback is partially folded, preventing injury to occupants and simplifies the unfolding process by reducing the necessary force, thereby enhancing user convenience.

Implementation Method 1

a restoring spring configured to apply, when a first end of the restoring spring is fixedly coupled to the spring mounting bracket, and a second end thereof is caught and supported by a fixed support end integrally provided in the cushion bracket, elastic restoring force to the back side frame so as to allow the back side frame to be rotated in a folding direction of the seatback

Methodology Applied

Scientific EffectElastic restoring force: Elasticity

Implementation Method 2

a reverse spring has a first end fixedly coupled to the spring mounting bracket and a second end supported while being caught by a first spring support end integrally provided on the back side frame in an unfolded state of the seatback

Methodology Applied

Scientific EffectElastic restoring force: Elasticity

Data Source

PatentUS12269377B2Vehicle seatback folding device

Publication Date: 2025.04.08 HYUNDAI TRANSYS INC

AI summary

A vehicle seatback folding device includes: a cushion bracket; a back side frame rotating on the cushion bracket; a spring mounting bracket coupled to rotate integrally with the back side frame around a hinge-coupling part; a return spring for applying, to the back side frame, elastic restoring force for rotating the back side frame in the folding direction of a seatback; and a reverse spring supported in a state in which a first end portion is caught by the spring mounting bracket and a second end portion is caught by a first spring support end.