TELESCOPIC DEVICE COMPRISING RETRACTABLE TORQUE TRANSMISSION SHAFT

摘要

The present invention relates to a telescopic device including a retractable torque transmission shaft, wherein a retractable torque transmission shaft comprises: a top member which is shaped into a round tube and on one side of which one or more first vertical movement guide grooves are formed; an intermediate member which is shaped into a round tube, on one side of which one or more second vertical movement guide grooves are formed, and which has a first protrusion joined to a first vertical movement guide groove of the top member; and a bottom member which is shaped into a round tube and which has a second protrusion to be joined to a second vertical movement guide groove of the intermediate member. The top, intermediate, and bottom members are joined together around the same shaft. The telescopic device including a retractable torque transmission shaft includes one or more retractable torque transmission shafts inside a round-tube-shaped telescopic boom and varies the length of the retractable torque transmission shaft in accordance with the length variations of the telescopic boom.