Stretchable webbing, inflatable belt, and inflatable belt apparatus
A technology for a stretchable webbing is provided including a long inflatable belt for restraining a vehicle occupant, which is effective in ensuring the webbing rigidity and achieving the reduced product width of the webbing. In one embodiment, the stretchable webbing includes a long inflatable belt for restraining a vehicle occupant, a weft yarn of the stretchable webbing having a first filament element and a second filament element which extend adjacent to and in parallel with one another, where the first filament element and second filament element have different heat-shrinkage ratios.
1. An inflatable belt apparatus comprising:
a seat belt assembly;
a retractor;
a releasable locking mechanism for releasably securing the seat belt assembly about a vehicle occupant;
an inflatable bag associated with a stretchable portion of the seat belt assembly; and
a compacted weft yarn of the seat belt assembly extending across the entire lateral extent of a rigid portion of the seat belt assembly configured and arranged to allow for the rigid portion to be received in the retractor,
wherein the stretchable portion and rigid portion include an inserting yarn and knitting yarns extending longitudinally, and the inserting, knitting and weft yarns are of polymeric material thermally treated at a predetermined temperature so at least a portion of the inserting yarn and a portion of the knitting yarns are melted and fused to the other yarns, and so that the weft yarn shrinks more than the inserting yarn and the knitting yarns.
2. The inflatable belt apparatus of claim 1 , wherein the inflatable bag is disposed within the stretchable portion.
3. The inflatable belt apparatus of claim 2 , wherein the stretchable portion has a hollow configuration and is not received in the retractor.
4. The inflatable belt apparatus of claim 1 , wherein the inflatable bag is cylindrical.
5. The inflatable belt apparatus of claim 1 , wherein the inflatable bag has an envelope shape.
6. The inflatable belt apparatus of claim 1 wherein the stretchable portion includes the weft yarn so as to not extend across the entire lateral extent of the stretchable portion.
7. The inflatable belt apparatus of claim 1 wherein the weft yarn includes a first weft filament and a second weft filament, the first weft filament having a first heat-shrinkage ratio, the second weft filament having a second heat-shrinkage ratio, the second heat-shrinkage ratio being higher than the first heat-shrinkage ratio.
8. The inflatable belt apparatus of claim 7 , wherein the first weft filament and the second weft filament extend adjacent and parallel to each other.
9. The inflatable belt apparatus of claim 7 , wherein the first weft filament is a core portion, the second weft filament is a sheath portion, the core portion disposed within the sheath portion.
10. The inflatable belt apparatus of claim 7 , wherein the first weft filament has a first fusing point, the second weft filament has a second fusing point, the first fusing point being lower than the second fusing point, with the first and second weft filaments being adjacent so that heating of the weft yarn to a temperature of at least the first fusing point but below the second fusing point bonds the first weft filament to the knitting yarns, and the second weft filament to the knitting yarns with the first weft filament.