The present invention relates to a limit apparatus for opening and closing a cover for a greenhouse. More specifically, the limit apparatus for opening and closing a cover for a greenhouse is characterized by that a cover for sealing a gear box is vertically separated and connected so as to prevent the permeability of moisture including rain water into the gear box installed in an opening and closing unit for a greenhouse and an operating lever of a limit switch which is positioned at the lower direction of the gear box so as to provide the use convenience for an operator to facilitate the operation. The opening and closing unit for a cover according to the present invention comprises: a motor mounting unit for mounting a motor a gear box having an opening in front of one side of the motor mounting unit a worm gear having worm gear teeth within the gear box, and the other end projected toward outside and connected to a pinion gear, and rotating in gear with a reduction gear installed on a motor driving shaft, and the pinion gear a vertical gear unit having helical gear teeth in the center to correspond to the worm gear teeth of the worm gear, and bevel gear teeth formed on the upper end and rotating a horizontal gear unit having bevel gear teeth and pinion gear teeth successively formed on one end so as to correspond in perpendicular to the bevel gear teeth of the vertical gear unit, and rotating a pair of spur gears having a spring inserted and connected to one end on the front and back surfaces of the horizontal gear unit, and an integral stopper so as to interfere the pinion gear teeth and a limit switch to correspond to the pinion gear teeth of the horizontal gear unit on the outer periphery, and rotating and the limit switch under the spur gears for interfering the operation of a motor when the spur gears rotate.COPYRIGHT KIPO 2015본 발명은 비닐 하우스의 비닐 개폐기용 리미트 장치에 관한 것으로서, 더욱 상세히 설명하면 비닐 하우스용 비닐 개폐기에 구비된 기어 박스 내부로 빗물을 포함한 수분 침투가 용이하지못하도록 기어 박스를 밀폐하는 커버가 수직방향으로 분리 및
