The document discusses Jacton Electromechanical Co., Ltd.'s multiple screw jacks lifting systems. The systems can include components like bevel gearboxes, screw jacks, flexible couplings, connecting shafts and bearings. The systems can be electrically operated and offer precision positioning for lifting heavy loads of up to several hundred tons. The document also provides details on the transmission efficiencies of different configurations of two, three and four screw jack lifting systems.