DEVICE FOR GREENHOUSE CURTAIN AND VENTILATION SYSTEM Russian patent published in 1999 - IPC

FIELD: agriculture, in particular, commercial and individual greenhouses. SUBSTANCE: device has combined screw transmission mechanism and screw-nut mechanism for transmitting motion to small window of ventilation system or curtain beam of curtain system. Mechanisms are connected by internal thread of driven gear of screw transmission engaged with external screw thread of screw-nut pair. Driven gear is fastened so that it is prevented from longitudinal motion to reduce drive shaft torque as compared to, for instance, rack transmission at equal resistance force on end member. Self-braking of curtain and ventilation system end link allows manual or combined drive of the system to be employed. EFFECT: increased efficiency, simplified construction and enhanced reliability in operation. 9 dwg