Variable Warp Density Pulling Means for Airbag Stitching
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Solution Overview
Problem
Existing pulling means for airbag modules, such as tethers, cannot be directly stitched onto the airbag due to their design, limiting their integration with airbag modules and the control of discharge orifices in vehicle safety systems.
Innovation Solution
Elongate woven pulling means with varying warp densities, allowing for different widths to be manufactured in one step on a loom, enabling direct stitching onto the airbag and efficient force transmission, combining the functionality of a strap and a cord for precise control of airbag deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If narrow strips are used for tether release means, then the area available for stitching onto the airbag increases, but the rupture load becomes insufficient and the strip is too wide for the activation unit corridor
Solution Approach 1:
The pulling means features longitudinal portions with different warp densities, creating local variations in width and strength. The narrower portions have higher warp density for increased rupture load, while wider portions provide sufficient stitching area, allowing each section to be optimized for its specific function
Solution Approach 2:
The invention changes the warp density parameter along the length of the pulling means to achieve different widths. By varying this structural parameter, the pulling means simultaneously achieves narrow sections for high strength and wide sections for adequate stitching area, resolving the contradiction between these two requirements
2Strength
If cords made of high-strength polyethylene fibers are used, then the rupture load is sufficient, but the cord cannot be stitched directly onto the airbag requiring additional textile fabric loops
Solution Approach 1:
The invention merges the functions of the cord and the stitching strip into a single integrated pulling means. The varying warp density allows the same component to provide both high rupture load (in narrow portions) and sufficient stitching area (in wider portions), eliminating the need for separate textile fabric loops and reducing overall device complexity
Solution Approach 2:
The pulling means serves multiple functions simultaneously: it provides high rupture load like a cord, offers sufficient stitching area like a narrow strip, and can be directly attached to the airbag. This multi-functionality eliminates the need for additional components and simplifies the overall system
3Length of moving object
If the pulling means is narrower to fit the activation unit corridor, then the width for stitching is reduced, but the rupture load becomes insufficient
Solution Approach 1:
Different longitudinal portions of the pulling means have different warp densities, creating local variations in width. The narrower portions provide high rupture load while wider portions provide adequate stitching area, allowing the pulling means to meet both requirements without compromise
4Ease of manufacture
If additional textile fabric loops are stitched onto the airbag, then the cord can be attached, but the construction space and manufacturing steps increase
Solution Approach 1:
The invention combines the cord and stitching strip into a single pulling means component. This integration eliminates the need for separate textile fabric loops, reducing the number of components and simplifying both the construction process and manufacturing steps while maintaining adequate attachment capability
Data Source
AI summary
Elongate woven pulling means (10) for an airbag module comprises plural longitudinal portions (12, 14, 16, 18, 20) that have different warp densities. An airbag module for a vehicle safety system comprises an airbag, pulling means (10) coupled to the airbag and an activation unit coupled to the pulling means for releasing the pulling means upon actuation of the activation unit. The pulling means (10) is an elongate woven pulling means having different warp densities which is fastened to the airbag by a first end portion (12) of low warp density, preferably by stitching, and is coupled to the activation unit by a longitudinal portion (16) of high warp density. A method of manufacturing such pulling means (10) comprises the steps of: weaving a longitudinal portion (12; 20) on a loom of low warp density; and weaving a further longitudinal portion (16; 14, 18) on the loom having high or increasing warp density in the same working step. For weaving an adjustable reed having different widths is employed.