Electrical locking device with fail-safe emergency release

An electrically operable locking device (400), for the locking of a gate (402), the gate controlling the access through a passage, the device (400) provided for locking the gate (402) by electrically extending a drop bolt (302) from a housing (300) and engaging the drop bolt with a fixed bolt reception element (403), and for releasing the gate (402) by electrically retracting the drop bolt (302) into the housing (300) and disengaging the drop bolt from the fixed bolt reception element (403), the locking device (400) comprising:

• a. a frame (200) for fixing the locking device (400) to the gate (402),
• b. the frame (200) supporting the housing (300), which is arranged mechanically movable with respect to the frame (200) between an extended position of the housing (300), whereby, if the drop bolt (302) is extended from the housing (300), the drop bolt (302) is engaging with the fixed bolt reception element (403) and the gate (402) is locked, and a retracted position of the housing (300) whereby, if the drop bolt (302) is extended from the housing (300), the drop bolt (302) is disengaged from the fixed bolt reception element (403) and the gate (402) is released, and
• whereby the housing (300) is provided with a mechanical locking mechanism (301) provided for locking the housing (300) to the frame (200) in at least the extended position and with the release of the mechanical locking mechanism (301) allowing the mechanical movement of the housing (300) from the extended position of the housing (300) into the retracted position of the housing (300) and whereby the locking device (400) further comprises a resilient element (309) provided for, upon release of the mechanical locking mechanism (301), by the relaxation of the resilient element (309) urging the housing (300) noticeably out of its extended position.