Negative and Positive Shedding Configurations
topic
Positive shedding systems control heald frame movement in both up and down directions through mechanical linkage or cam follower, ensuring precise shaft position control at all machine speeds, while negative shedding systems use the shedding mechanism to drive shaft movement in one direction with spring return for the opposite direction, limiting maximum speed from spring inertia but providing simpler lower-cost mechanism design.
Role
Determines the maximum weaving machine speed achievable with the shedding system and the reliability of shed formation timing accuracy that governs insertion reliability, with positive shedding being preferred for high-speed air-jet looms where spring return inertia and compliance would cause shed timing errors at high picks per minute that negative spring return systems cannot achieve reliably.