FIELD: mechanical engineering; screw hoists. SUBSTANCE: feed unit with nut and controlled force transmission drive used in mechanical employing a screw, particularly in construction coupled with device for loading materials onto road vehicles for subsequent transportation, has nut arranged in casing moved translationally along guide profile under action of screw set into rotation by external source and passing through sliding casing, and mechanism for locking and releasing the rotating nut. Unit has rotary support for free end face of loaded nut on adjoining cross wall of movable casing and flexible connection between rotary support and upper adjoining cross wall of movable casing. Grooves separated by teeth are made on side surface of nut. Grooves are longitudinal and are arranged along axis. Locking or release mechanism consists of two locks, each capable of turning around its axis parallel to screw. When nut is blocked, free edge of each lock gets into one of nut grooves. Locks of locking or release mechanism are installed together with flexible device to allow the device hold the lock in nut, and when drive operates, pushing force releases the locks. EFFECT: improved reliability, simplified control mechanism. 12 cl, 9 dwg
