A chain lock includes a main body, a rotatable part, a cylinder, a plug provided with a tailpiece, and a chain. The main body defines therethrough a first channel and a second channel. The rotatable part defines therethrough a third channel. The rotatable part is rotatably mounted to the main body. The cylinder is slidably fitted into the first channel of the main body and biased by a compression spring. The plug together with the tailpiece is rotatably mounted in the cylinder. The chain includes a series of rings, one ring of which is located in the second channel of the main body and inserted through by the cylinder. In use, a second ring of the chain can be located in the third channel of the rotatable part to be inserted by the cylinder, and the plug can be rotated by a key to have the cylinder fixed in place.

A method for mutually controlling and unlocking a dual plug in a lock includes: unlocking a code of a first plug first, the first plug restricting unlocking of a second plug, the second plug restricting rotating of the first plug before the code of the first plug is unlocked. after unlocking the code of the first plug, the first plug translating to a second position from a first position using a preset position difference, the first plug being unable to rotate during the translation; after moving the first plug to the second position, the first plug releasing a restriction on the second plug, the second plug still restricting the rotating of the first plug; and unlocking the code of the second plug, the first plug and the second plug being able to rotate synchronously so as to unlock the lock after unlocking the code of the second plug.

A lock assembly for use in a vehicle includes a key having a key head and a key shaft. The key shaft defines a recess. A lock cylinder defines a slot and a channel. The slot is in communication with a first end of the channel. A switch door is positioned to cover the slot. A light source is positioned at a second end of the channel. The light source is positioned to illuminate through the channel. A sensor is configured to detect the key. The sensor is coupled with the light source. The sensor is configured to actuate the light source based on a location of the key. A luminescent structure is positioned on the key shaft within the recess.

A chain lock includes a main body, a rotatable part, a cylinder, a plug provided with a tailpiece, and a chain. The main body defines therethrough a first channel and a second channel. The rotatable part defines therethrough a third channel. The rotatable part is rotatably mounted to the main body. The cylinder is slidably fitted into the first channel of the main body and biased by a compression spring. The plug together with the tailpiece is rotatably mounted in the cylinder. The chain includes a series of rings, one ring of which is located in the second channel of the main body and inserted through by the cylinder. In use, a second ring of the chain can be located in the third channel of the rotatable part to be inserted by the cylinder, and the plug can be rotated by a key to have the cylinder fixed in place.

A lock can include attack-resistant and/or weather-resistant features. Attack-resistant features can include a sacrificial link between a locking mechanism and an external keyway covering an exterior face of the locking mechanism. The sacrificial link can break during a torque attack on the lock such that the full force of the torque attack is not applied to the locking mechanism. Weather-resistant features can include drain openings in one or more housing components external to the locking mechanism to facilitate drainage of liquid matter from the lock before the liquid matter reaches the locking mechanism.

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 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 locking system includes a tamper-resistant lock and key. The tamper-resistant lock can include a cylindrical lock body with an upper portion having an engagement surface defining a pattern of engagement features, a housing, and a hidden component sized and shaped to fit within the housing that includes an internal lock base into which the cylindrical lock body fastens and a padlock pin configured to secure the internal lock base to a hasp or staple. The key operable for use with the tamper-resistant lock can include a cylindrical key body defining an engagement cavity configured to receive the engagement surface of the cylindrical lock body, a set of complementary engagement features, a plurality of retractable engagement members, and a retractable collar at least partially covering the cylindrical key body.

A locking device which multiple operators can use as a hasp lockout device to restrict access to controlled devices and areas. The locking device enables the operator to prevent unauthorized personnel from accessing the key slot of the locking device. Furthermore, the operator can employ multiple padlocks in a sequential manner so as to establish a sequence of locking or unlocking, improving workplace safety.

Trailer theft is a widespread problem, and existing locks have failed to solve the problem for a number of reasons. Some locks require permanent modification of a trailer jack, while others are easy to break into. The present invention provides a detachable trailer jack locking assembly including a retention shell couplable to a trailer jack body. The retention shell is sized and shaped to surmount an upper end of an outer tube of the trailer jack. The retention shell also includes a slot configured to accept a handle of a lifting assembly on the trailer jack. The assembly includes an attachment point disposed on the outer tube of the trailer jack. A lock is adapted to secure the retention shell against the outer tube by coupling with the attachment point. When engaged, the handle is immobilized within the slot, thereby rendering the lifting mechanism of the trailer jack inoperable.