Child Seat Shoulder Strap Force Limiting Mechanism

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Solution Overview

Problem

Existing child seats face challenges in simplifying the adjustment of force-limiting means to accommodate the size and weight of children, requiring complex steps and reconfiguration of the belt system during use.

Innovation Solution

A child seat design featuring a holding device with a force-limiting mechanism that shifts from a locked position to a second position upon exceeding a predetermined force, allowing energy absorption during impact while remaining dimensionally stable, and an adjustable device for setting belt length and position to fit different child sizes, incorporating latching elements for secure holding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If force-limiting devices are adjusted to accommodate different child sizes, then adaptability is improved, but device complexity increases due to required reconfiguration of the belt system

Engineering Contradiction:
Improveadaptability to child sizeVSAvoidcomplexity of adjustment
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The belt system is pre-configured with multiple fixed length positions and corresponding force-limiting devices at predetermined locations. Before use, the appropriate belt length and force-limiting device are selected and installed in advance, eliminating the need for complex reconfiguration during adjustment. This preliminary preparation enables easy adaptation to different child sizes while maintaining simple operation.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If multiple force-limiting devices with different thresholds are provided, then adaptability is improved, but ease of operation deteriorates due to required repositioning of the belt system

Engineering Contradiction:
Improveadaptability to child weightVSAvoidease of adjustment
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

Multiple force-limiting devices with different force thresholds are pre-installed at fixed positions along the belt system. The appropriate device is selected and installed in advance based on the child's weight, eliminating the need for complex repositioning operations during adjustment. This preliminary configuration enables easy adaptation while maintaining simple operation.

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If the restraint device moves from first locked position to second locked position upon force threshold exceeded, then energy absorption is improved, but reliability may be affected by position transition during impact

Engineering Contradiction:
Improveenergy absorption capacityVSAvoidreliability of restraint
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The restraint device is pre-configured with multiple locked positions and corresponding force-limiting devices at predetermined locations along the belt path. When impact force exceeds the threshold of the currently engaged force-limiting device, the device automatically transitions to the next locked position, absorbing energy through this controlled movement. This preliminary configuration of multiple positions enables energy absorption while maintaining reliability, as the transition to subsequent locked positions ensures continued restraint.

Inventive Principle:
Principle #10Preliminary action

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

This design simplifies the adjustment and ensures reliable force limitation during impacts, reducing the risk of incorrect operation and providing adaptive protection for children of varying sizes without the need for complex reconfiguration, enhancing safety and reducing production costs.

Implementation Method 1

In the event of an impact on the restraint device (29), the restraint device (29) is moved from a first locked position to a second locked position, when a predetermined limit force is exceeded by the shoulder belt (28)

Methodology Applied
Scientific EffectEnergy absorption: Deformation

Data Source

PatentEP3393864B1Child seat for attaching to a motor vehicle seat
Publication Date: 2023.07.26 CYBEX GMBH
  • EP3393864B1 patent drawingFigure 1a~2
  • EP3393864B1 patent drawingFigure 3a~4
  • EP3393864B1 patent drawingFigure 5~6c

AI summary

The invention relates to a child seat for attaching to a motor vehicle seat, comprising a seat region (25) and a back section (26), at least one shoulder strap (28), at least one retaining device (29) for holding and/or deflecting the shoulder strap (28), and at least one force limiting means (12, 14, 7), which is designed such that the retaining device is transitioned from a first arrested position to a second arrested position upon exceeding a predetermined limit force exerted by the shoulder strap or by the shoulder straps on the retaining device (30) in case of an impact.