Abstract: There is provided a door mechanism comprising a door and a door closure mechanism for moving the door between a first, open, position and second, closed position. The door closure mechanism comprises a drive motor coupled to a drive screw, the drive screw having a first, right handed thread portion and a second, left handed thread portion, a first drive nut threadedly engaged with the first thread portion, a second drive nut threadedly engaged with the second thread portion, a first drive linkage pivotally coupled to the first drive nut at one end and to the door at a second, opposed end, and a second drive linkage pivotally coupled to the second drive nut at one end and to the door at a second, opposed end.

Abstract: A linear actuator comprises an actuator housing defining a bore. A drive element is received in the actuator housing bore. The drive element comprises tubular portions receiving first and second ball nuts arranged at respective distal ends thereof. The ball nuts are threaded in opposite directions to one another. The drive element further comprises a drive coupling. The actuator further comprises first and second ball screws operatively engaged with the first and second ball nuts. Rotation of the drive element and thus the ball nuts relative to said ball screws causes the ball screws to move together in a linear path in opposite directions from one another.