Locking against rotation of electric motor of a linear actuator

A linear actuator (1) comprising:

• an electric motor (10);
• a spindle (4) driven by said reversible motor (10);
• and
• a spindle nut (6) mounted on the spindle (4) and secured against rotation, said spindle nut (6) being arranged to be moved between two end positions,
• said electric motor (10) comprising a stator attached to a motor housing (20) and a rotor comprising a motor shaft (31), where the motor (10) is adapted to be electrically controlled to selectively rotate the rotor in one of two opposite angular directions,
• wherein the electric motor further comprises an electromechanical locking mechanism (40, 60), said electromechanical locking mechanism (40, 60) comprising:
• an electromechanical transducer (41, 64), which is attached immovably in relation to the motor housing (20) and comprises an electromechanical solenoid and a nonrotating locking element (44), the electromechanical transducer (41, 64) being adapted to be electrically controlled to selectively shift the non-rotating locking element (44) between a projected and a retracted position;
• and
• a rotating locking element (45, 63) attached to the motor shaft (31) and comprising at least one cam (47, 61) projecting in a direction towards the transducer (41, 64), wherein the at least one cam (47, 61) comprises a non-engageable side opposite to an engageable side,
• wherein the nonrotating locking element (44) is arranged to project in a direction towards the rotating locking element (45, 63) and to interferingly lock with the at least one cam (47, 61), by selectively engaging the engageable side of the at least one cam (47, 61),
• wherein the electromechanical transducer (41, 64) is configured to control the engagement by keeping the nonrotating locking element (44) in a position not engaging the engageable side of the at least one cam (47, 61), when the electromechanical transducer (41, 64) is energized, and the electromechanical transducer (41, 64) further comprises a spring element arranged to keep the nonrotating locking element (44) in a position engaging the engageable side of the at least one cam (47, 61), when the electromechanical transducer (41, 64) is not energized,
• wherein the electromechanical solenoid operates about a longitudinal axis that is not coincident with a longitudinal axis of the motor shaft,
• whereby the electromechanical locking mechanism (40, 60) is configured to lock the motor shaft (31) against rotation in one rotational direction, thereby locking the motor (10) unidirectionally.