Variable Width Safety Belt Webbing for Load Distribution
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Solution Overview
Problem
Existing seat belt devices struggle to reduce occupant load effectively due to limited contact surface area of the diagonal belt section, leading to increased costs and space requirements with inflatable belt straps, which are not practical for widespread use.
Innovation Solution
A seat belt webbing design with a wider section in the longitudinal direction than a standard section, accompanied by a transition zone and a second belt retractor, allowing for even load distribution and reduced occupant stress without additional components like gas generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the contact surface of the diagonal belt section is enlarged to reduce chest compression, then the occupant load is reduced, but the winding width of the belt retractor must be increased which is not feasible for package reasons
Solution Approach 1:
The webbing is designed with different widths in different sections: a first section with width of 75-100 mm for chest contact to reduce compression, and a second section with standard width of 46-48 mm for winding. This local differentiation allows the webbing to provide both enlarged contact surface and compatibility with conventional retractors.
Solution Approach 2:
The webbing is divided into multiple sections with different functions: the first wider section for load distribution on the chest, the transition section for gradual width change, and the second narrower section for winding on the retractor. This segmentation enables each part to optimize its specific function without compromising the whole system.
2Object-affected harmful factors
If inflatable belt straps with gas generators are used to enlarge contact surface, then the occupant load is reduced, but the costs and space requirements significantly increase
Solution Approach 1:
The invention replaces expensive inflatable mechanisms with a simple woven webbing structure that achieves load distribution through its construction. The webbing uses conventional materials and weaving techniques to create a permanently enlarged contact section without requiring additional components like gas generators, sensors, or control systems.
Solution Approach 2:
The webbing parameters (width, weave density, thread arrangement) are changed in the first section to achieve the desired load distribution effect. The width is increased to 75-100 mm and the weave density is adjusted to 10-18 weft threads/cm, creating a structurally different but equally effective solution compared to inflatable alternatives.
3Area of stationary object
If the webbing is made wider in the first section to reduce occupant load, then the contact surface is enlarged, but the webbing may buckle or fold in the wider section
Solution Approach 1:
The weave density is locally increased in the first wider section to 10-18 weft threads/cm, creating a stiffer, more stable structure in the area most prone to buckling. This local reinforcement maintains webbing stability while preserving the enlarged contact surface area.
Solution Approach 2:
A transition section with gradually increasing width is introduced between the first and second sections. This gradual curvature change prevents sudden geometric transitions that would cause buckling, allowing the webbing to smoothly adapt from the narrow to wide section without folding or creasing.
4Object-affected harmful factors
If the webbing has high weave density in the first section to distribute load evenly, then the load distribution is homogeneous, but the manufacturing complexity increases
Solution Approach 1:
The webbing is manufactured in distinct sections with different weave densities using conventional weaving techniques. The first section uses 10-18 weft threads/cm for homogeneous load distribution, while the second section uses standard density. This segmentation allows each section to be optimized independently using standard manufacturing processes.
Solution Approach 2:
The weave parameters (thread count, thread spacing, weave pattern) are changed in the first section to achieve better load distribution. By adjusting these parameters within conventional weaving capabilities, the invention achieves improved performance without requiring complex or non-standard manufacturing processes.
Data Source
Figure 1
Figure 2~3
AI summary
The present invention relates to a belt strap (6) for a safety belt device (1) of a motor vehicle, the belt strap (6) being wider in a first section (13) than in a second section (12) relative to its longitudinal direction.