Shed Closing and Warp Protection Timing
topic
Shed closing timing determines the crank angle at which shafts begin moving from open shed to closed shed position, with shed closing timed to occur after weft insertion completion but early enough to complete crossing before beat-up forces the reed against the cloth fell, with shed protection settings on modern looms automatically delaying shed closing when weft insertion monitoring detects incomplete insertion to prevent the inserted but short weft from being beaten into the fabric before the operator can remove it.
Role
Ensures that shed closing occurs in the correct sequence relative to weft insertion completion and beat-up, with protection timing being a critical fabric quality mechanism that prevents the weaving-in of incorrectly inserted weft by maintaining the open shed that allows weft removal when insertion monitoring detects problems, with protection timing settings being particularly important at high weaving speeds where the time margins are small and where incorrect shed closing timing creates warp breaks from reed contact with partially crossed warp ends.