US Patent 7063285 Cassette device for reliable filament delivery

A cassette for use in delivering a continuous length of filament provides improved reliability by employing means for preventing tangling of the filament in the cassette. The cassette has a substantially closed housing defining a chamber in which a spool is rotatably mounted, and a path from the chamber to an exit orifice. A length of filament is wound around the spool and has a free strand positioned in the path. The filament strand is advanced along the path and delivered through the exit orifice by a means for advancing. Tangling is prevented by locking the spool during transport of the cassette to maintain a tight wind, and by guiding the filament strand along a snag-free path as it is withdrawn from the cassette. In the exemplary embodiments, a removable pin locks a flange or hub of the spool, and the filament strand is withdrawn through a tubular guide member.