Abstract: A rotational-locking member such as an endless screw for actuating a sliding door by means of a nut is locked in position by rotational displacement of the nut and is unlocked by means of a device comprising a pulley coupled to the endless screw and rigidly fixed to a clutch-disk. A second clutch-disk slidably mounted on a square sleeve of a bevel-pinion can be rotated by means of a pair of bevel-pinions and a lever. A lug of the second disk cooperates with a helical groove of a stationary cam in order to subject the disk to a helical movement, the rotational motion component of which is imparted to the endless screw after engagement of the disks in order to unlock the screw.

Abstract: A sliding door of the type employed in public transport vehicles and driven by an electric motor comprises at least one door-leaf coupled with a nut mounted on an endless screw which is driven in rotation in order to open and/or close the door. The nut is displaced in translational motion within a guide which prevents rotational motion. The locking device comprises means for interrupting the translational displacement of the guided nut at the end of travel and for permitting angular rotation of the nut with the endless screw, means for limiting the angular displacement of the nut and finally means for limiting the translational motion of the nut if it is displaced along the endless screw and no longer engaged in the guide.

Abstract: The sliding door is constituted by at least one door-leaf which is stabilized by two parallel toothed racks disposed in meshing engagement with two pinions, the pinions being coupled together by means of a coordinating shaft surrounded by a connecting tube. Two crank-arms attached to the tube are pivotally mounted on a stationary structure which is attached to the door-frame. Operating means comprising a rotary motor and a mechanism for driving the pinions of the leaf-stabilizing system are rigidly fixed to at least one crank-arm, the motor being associated with an auxiliary pinion which is in mesh with one of the stabilizing pinions.

Abstract: The door comprises at least one sliding leaf which is capable of engagement and disengagement transversely within the door-frame, two separate toothed racks being mounted on each leaf and each associated with a pinion supported by a guided carriage, the two pinions being coupled by means of a coordinating shaft. Operating means comprising a motor and a mechanism for driving the pinions are rigidly fixed to at least one of two crank-arms, each crank-arm being pivotally connected to a carriage and to the door-frame.