Patent ID: 8733510

Claim:
A locking mechanism for fixing a linear actuator comprising a piston rod and a cylinder, the locking mechanism comprising: a plurality of first positive locking elements arranged lengthwisely on the outside circumference of the cylinder and in certain distances to one another, at least one second positive locking element configured to move together with the piston rod when the linear actuator is activated, and thereby to pass a segment of the cylinder, wherein the at least one second positive locking element is positively engageable with one of the plurality of first locking elements at discrete positions of the cylinder in lengthwise direction, so that the piston rod is fixed relative to the cylinder, wherein the plurality of first positive locking elements comprises a plurality of grooves surrounding the cylinder on the exterior circumferential side of the cylinder, and wherein the at least one second positive locking element is a spring washer clamp directly positively engaging one of the plurality of grooves when the at least one second positive locking element is in a locked position, wherein the at least one second positive locking element is adapted to assume a locked position, wherein the at least one second positive locking element is engaged with one of the plurality of first positive locking elements to form a positive locking, or assume an unlocked position, wherein the positive locking is suspended, wherein the at least one second positive locking element is adapted to create a reset force trying to move the second locking element from the unlocked position to the locked position; wherein the spring washer clamp comprises at the open ends thereof an unlocking actuator, by activation of which unlocking actuator the at least one second positive locking element is held in the unlocked position counteracting the reset force; and wherein the activation of the unlocking actuator is performed using a common power input coupled to and operating the unlocking actuator and the linear actuator, so that in case of a failure of the common power input of the linear actuator and of the unlocking actuator, the at least one second positive locking element is moved to the locked position due to the reset force no longer being countered by the deactivated unlocking actuator.