A padlock is configured to be locked and unlocked by a key and includes a lock body having an internal cavity with a locking mechanism and a keyway extending through the lock body into the internal cavity to provide access to the locking mechanism by the key. The locking mechanism is configured to be selectively moved over a range of positions when the key is received therein to lock and unlock the padlock. The keyway has an eccentric profile that permits the key to be removed from the locking mechanism in only a single position of the range of positions.

A padlock configured to be locked and unlocked by a key includes a key-retaining cover. The padlock includes a lock body having an internal cavity with a locking mechanism received therein. The locking mechanism is a linear lock configured to receive the key through a keyhole to lock and unlock the padlock. A direction of insertion of the key into the locking mechanism is parallel with a direction of displacement of a plurality of tumblers in the locking mechanism thereby creating an outward ejection force on a fully-inserted key. The cover is disposed on the locking mechanism proximate the keyhole. The cover is configured to retain the key in position relative to the locking mechanism against the outward ejection force after the key is received in therein.

A lock assembly has a lock and a dust cover. The dust cover has a cover body, a connecting portion and a mounting ring. An annular insertion wall protrudes from a surface of the cover plate. Two opposite ends of the connecting portion are connected to the cover body and the mounting ring respectively. The lock has a lock cylinder. A keyhole is formed in one end of the lock cylinder. The lock cylinder has a door abutting portion and an annular mounting groove. The door abutting portion abuts against a door when the lock is mounted on the door. The mounting ring of the dust cover is rotatably mounted around the annular mounting groove. The annular insertion wall can be mounted in and engages with the keyhole. The rotatable dust cover makes the installation, use, and maintenance of the dust cover more convenient.

A lock unit includes a case, an operation unit and an electric control unit. A shackle is connected to the case, and the operation unit controls the first end of the shackle to be disengaged from the case. A touch screen is connected to the outside of the cover so as to control the electric control unit which controls the operation unit to easily and quickly unlock the lock unit by popping the first end of the shackle out from the case.