Airbag Fabric Waste Reduction via Segmented Layer Design
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Solution Overview
Problem
Conventional air-bag manufacturing methods result in significant fabric wastage due to the 'butterfly' shape cutting technique, which is inefficient and costly.
Innovation Solution
The air-bag is constructed using two rectangular layers cut from the same fabric portion, with specific edge orientations and cut angles to minimize waste, and attached via a single continuous seam, allowing for efficient use of fabric and reduced manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the conventional 'butterfly' shape cutting technique is used to manufacture air-bags, then the air-bags can be formed with the required shape and structure, but significant fabric wastage occurs
Solution Approach 1:
The air-bag is divided into two separate rectangular layers instead of being cut as a single butterfly shape. Each layer is cut independently from the fabric sheet, allowing for more efficient fabric utilization and reduced wastage while maintaining the functional integrity of the air-bag structure
Solution Approach 2:
The design transitions from a two-dimensional butterfly shape to a three-dimensional construction using two separate rectangular layers that are folded and joined. This dimensional change enables more efficient fabric cutting patterns and reduces material wastage while achieving the same functional form
2Loss of substance
If multiple air-bag panels are positioned close together on the fabric sheet to minimize waste, then fabric utilization improves, but the manufacturing process becomes more complex
Solution Approach 1:
By segmenting the air-bag into two standard rectangular layers, the manufacturing process can use simple, repeatable cutting patterns that allow multiple panels to be efficiently arranged on fabric sheets, reducing waste without significantly increasing process complexity
Solution Approach 2:
Changing the geometric parameters of the air-bag construction from a butterfly shape to two rectangular layers allows for standardized cutting dimensions that optimize fabric utilization while simplifying the manufacturing process through repetition and standardization
3Strength
If the air-bag is inflated to a thickness of approximately 100mm across the side protection face, then adequate protection is provided, but the gas volume and inflation pressure requirements increase
Solution Approach 1:
The air-bag uses flexible fabric layers that can be folded and joined to create the desired thickness profile. This allows the air-bag to achieve the required 100mm protection thickness at the side face while using thinner fabric layers overall, reducing the total gas volume needed for inflation
Solution Approach 2:
By using folded layers instead of a single thick structure, the air-bag achieves its protective thickness through three-dimensional folding rather than uniform thickness. This dimensional approach reduces the overall gas volume required while maintaining the necessary protection capability
Data Source
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AI summary
An air-bag for use in a vehicle, the air-bag comprising a first layer (12) having a first edge (16) and a second edge (17). The air-bag further comprises a second layer (13) having a third edge (21) and a fourth edge (22). The layers (12, 13) are offset rotationally relative to one another such that the first edge (16) is at an angle A relative to the third edge (21) and a first part (26) of the second layer (13) is superimposed on a first part (27) of the first layer (12) to define a reinforced part (28). A second part (30) of the first layer (12) is folded about a fold line (29) that intersects the first edge (16) and which is substantially at the angle A relative to the first edge (16) so that the second part (31) of the second layer (13) is superimposed on a second part (30) of the first layer (12) to define a chamber (32) therebetween. The layers (12, 13) are attached to one another at least partly around a periphery of the chamber (32) so that the chamber (32) may be inflated by gas provided by a source of gas.