Vehicle Door Ajar Retaining Tab With Curved Stress Distribution

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing temporary devices for holding opening elements in a motor vehicle assembly, such as doors, degrade quickly due to stress concentration zones and paint retention issues, leading to premature failure and aesthetic defects during the assembly and painting process.

Innovation Solution

A temporary device with a tab featuring an intermediate zone configured to distribute stresses along its length, an elastic deformation element with curved sections, and a stop to limit movement, reducing stress concentration and enhancing durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the tab is made as a simple straight connection between the body and the housing edge, then the device structure is simple, but stress concentrates at the ends of the tab causing premature failure

Engineering Contradiction:
Improvetab structureVSAvoiddevice lifespan
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies curvature to the tab by introducing an intermediate zone with at least one curved section between the first end and second end. This curved geometry redistributes the stress along the tab length, preventing stress concentration at the ends and thereby extending device lifespan while maintaining structural simplicity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Volume of moving object

If the device components are positioned close together to minimize space, then the assembly is compact, but paint is retained in the gaps causing aesthetic defects

Engineering Contradiction:
Improvedevice sizeVSAvoidpaint retention
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The curved intermediate zone creates a smooth transition that eliminates sharp corners and gaps where paint could be trapped. The curvature ensures paint flows smoothly over the tab surface without accumulating, preventing aesthetic defects while maintaining compact device dimensions.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If the tab is made rigid to maintain structural integrity, then the device is strong, but it cannot deform elastically to accommodate housing variations

Engineering Contradiction:
Improvetab strengthVSAvoidelastic deformation capability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The curved intermediate zone acts as a flexible element that can deform elastically under stress while the straight sections maintain structural strength. This curved geometry allows the tab to bend and adapt to housing variations, providing both strength and flexibility simultaneously.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 extends its lifespan by evenly distributing stresses, preventing breakage and paint retention, thus maintaining optimal assembly and painting conditions.

Implementation Method 1

the tab comprises, disposed between the first end and the second end, an intermediate zone comprising at least one section configured to distribute stresses applied to the tab

Methodology Applied
Scientific EffectStress distribution:

Implementation Method 2

the retaining means deforms elastically under the action of the stresses and then retracts

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4143407B1Heavy-duty device for temporarily holding an opening element in an ajar position
Publication Date: 2026.04.01 EXSTO THERMOPLASTICS
  • EP4143407B1 patent drawingFigure 1a~2
  • EP4143407B1 patent drawingFigure 3a~4
  • EP4143407B1 patent drawingFigure 5~6

AI summary

Device (1, 21, 31, 41, 51, 616, 71, 810, 91, 100) for temporarily holding an opening element (52) in an ajar position relative to a stationary element (51) of a body of a vehicle, comprising a body (14, 414, 614) provided with at least one mounting means (2, 11), and a retaining means (15, 415, 615) comprising a tab (6, 46, 66) a first end (63) of which is designed to cooperate with a first flange (53a) of a housing (53) and a second end (61, 461, 661) of which provides a junction with the body (14, 414, 614), characterised in that the tab (6, 46, 66) comprises, between the first end (63) and the second end (61, 461, 661), an intermediate area (62, 462, 662) comprising at least one section configured to distribute stresses applied to the tab (6, 46, 66) when the device is moved to the ajar position or the fully open position (1, 21, 31, 41, 51, 616, 71, 810, 91, 100).