Lift driving device

A drive device for an elevator of the type comprising a cage secured to a frame co-operating with vertical guide means, the drive device being characterized in that it comprises:

• a moving horizontal cross-member (20) independent from the frame and co-operating with the vertical guide means (12);
• an actuator comprising a cylinder (24) and a rod (26) that is vertically movable, the actuator cylinder being secured to one of the elements constituted by the frame (16, 18) and the cross-member, the end (26a) of the actuator rod being secured to the other of said two elements;
• first and second sets of pulley wheels (32, 34) mounted to rotate freely about respective horizontal axes (56, 60) secured respectively to the moving cross-member and to the frame;
• a cable (36) passing over said sets of pulley wheels to constitute a pulley block system, a first end (40) of said cable being secured to the top end of an elevator shaft and the other end (38) of the cable being secured to one of said two elements;
• and
• means (62) for controlling displacement of the actuator rod relative to the actuator cylinder.