Inner Stringer Reinforcement for Seatbelt Reel Mounting

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for reinforcing vehicle side rails and attaching seat belt retractors are bulky and complex, requiring additional parts and increasing manufacturing complexity.

Innovation Solution

A reinforcement structure for the seat belt retractor mounting area is integrated into the inner side member, comprising stamped sheet metal angles and gussets that reinforce the mounting area and the side member, allowing direct screw fixation without additional bulk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the thickness of side rails is increased and/or reinforcements are added to improve mechanical strength, then the mechanical strength in the event of a side impact is improved, but the device complexity and manufacturing complexity increase

Engineering Contradiction:
Improvemechanical strengthVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines the reinforcement element and the seat belt retractor attachment bracket into a single integrated component. The L-shaped reinforcement includes a vertical portion that attaches to the inner side member and a horizontal portion that serves as the mounting bracket for the seat belt retractor, eliminating the need for separate reinforcement and bracket components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reinforcement element serves multiple functions simultaneously: it strengthens the inner side member against side impacts, provides a mounting surface for the seat belt retractor bracket, and integrates the attachment functionality. This multi-functional design reduces the number of parts while maintaining both structural integrity and attachment capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a bracket extending along the vertical portion of the inner side member is used to attach the retractor, then the attachment is achieved, but the support becomes bulky and constitutes an additional part to manufacture, handle and fix

Engineering Contradiction:
Improveattachment reliabilityVSAvoidease of manufacture
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the reinforcement element and the attachment bracket into one integrated component. The horizontal portion of the L-shaped reinforcement directly serves as the mounting surface for the seat belt retractor, eliminating the need for a separate bracket that extends along the vertical portion.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts the essential attachment function from the bulky vertical bracket and relocates it to the horizontal portion of the reinforcement element, which is positioned optimally for mounting the seat belt retractor while maintaining structural reinforcement capabilities.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If the reinforcement is attached to the vertical portion for dual purpose, then both strengthening and attachment are achieved, but the support structure becomes bulky and requires additional parts

Engineering Contradiction:
Improvestructural strengthVSAvoidnumber of parts
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines the reinforcement and attachment bracket functions into a single L-shaped element. The vertical portion provides structural reinforcement while the horizontal portion provides the mounting surface, eliminating the need for separate components and reducing overall part count.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from a vertical-oriented support structure to an L-shaped configuration that utilizes both vertical and horizontal dimensions. This dimensional change allows the reinforcement to provide structural strength vertically while providing attachment capability horizontally, optimizing both functions simultaneously.

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

Data Source

PatentEP3953219B1Inner stringer reinforcement
Publication Date: 2026.03.04 STELLANTIS AUTO SAS
  • EP3953219B1 patent drawingFigure 1~2
  • EP3953219B1 patent drawingFigure 3

AI summary

The invention relates to a structure of a vehicle underbody (1). This structure (1) comprises in particular an inner stringer (5) having a vertical portion (5.1), an upper portion (5.2) and a lower portion (5.3) and comprising a region (7) for the attachment of a seatbelt reel, and a reinforcement (9) of the attachment region (7). In this invention, the attachment region (7) is moreover located on the upper portion (5.2) of the inner stringer (5) and the reinforcement (9) is also attached to said upper portion (5.2) and to at least one of the vertical portion (5.1) and the lower portion (5.3).