Patent ID: 6851287

Claim:
A lock, comprising a quick unlocking device including: a frame; a face plate mounted on a side of the frame; a drive shaft movably mounted in the frame; a latch bolt retractably mounted on the face plate and secured on a first end of the drive shaft to move therewith; a multi-stage dead bolt movably mounted in the frame and having a first end retractably mounted on the face plate and a second end having a first side formed with a plurality of arcuate locking grooves; a locking plate movably mounted in the frame and having an end formed with a locking block detachably locked in either one of the locking grooves of the dead bolt to lock the dead bolt; an inner crank pivotally mounted on the frame and having a first section secured on a second end of the drive shaft for moving the drive shaft and a second section formed with a pivot plate; and a hook plate movably mounted in the frame and having a first end pivotally mounted on the pivot plate of the inner crank and a second end formed with a hook portion located adjacent to the locking block of the locking plate, so that the hook portion of the hook plate is movable to urge and move the locking block of the locking plate to detach from the locking grooves of the dead bolt so as to release the dead bolt, such that the dead bolt is movable.