A PET bottle is prepared by cutting off the bottom, and the open rim is pushed between a pair of bearings, where a cutter slices the bottle into one long strip, as a driven spool rolls it up.

A PET bottle is prepared by cutting off the bottom, and the open rim is pushed between a pair of bearings, where a cutter slices the bottle into one long strip, as a driven spool rolls it up.

Their low cost, unmatched strength, and full-race mystique have driven their popularity. But they're not perfect-and they come with some serious drawbacks. A spool is basically a steel collar that ...

The device includes a frame, drive wheel, spool, gas generator, and power transmission element to retract the seat belt in response to high acceleration. A ratchet ring prevents seat belt extraction.