US Patent 10174531 Locking device

A locking device, in which a larger force is required only when a vertical moving block protruding from a lower surface of a locking hook is moved up and down while being in line contact with a vertical-movement support block, thus allowing the locking device to be easily used with a relatively smaller force. Further, the tilting guide is restored by a restoring force of a restoring member, so that no frictional force is generated between the tilting guide and the housing, thus preventing a noise from being generated and allowing for a smooth operation, thereby ensuring the ease of use.