US Patent 6845643 Combination lock

An inverted U-shaped combination lock is disclosed. The lock includes a male locking mechanisms, a push ring, a hollow spindle, a sealing ring, an abutment ring, number rings, and a spring. The lock can be opened without a password by inserting a key into a keyhole prior to turning an angle of 90 degrees of the key. A ridged section of the mechanism is changed from a higher position to a lower one for disengaging the mechanism from the lock for subsequent removal of the mechanism. The lock also provides help for the user to know the forgotten password and resetting the password.