Using Segen Locks, typical platen, mold, or tool setup change-out time can be reduced from hours to minutes. Quick-change devices include steel cylinder lock with corresponding knob. Designed to receive and mate with the conical male knob, cylinder lock positions knob within 0.0002 in with holding force of 25,000 lb per unit depending upon version. Cylinder lock holds positively in a static state, actuating when air pressure is applied to release or receive knob. Cylinder stays mechanically locked until air pressure is applied for release. Even if air pressure is lost, system provides secure, fail-safe hold.