The joint of the upper single vertical pole and the lower double vertical pole is connected by one of the single vertical pole and the double vertical pole. The main vertical pole and the auxiliary vertical pole are connected by rotating fasteners, and the number of fasteners shall not be less than 2. A cushion block shall be set at the bottom of each vertical pole, and vertical and horizontal sweeping poles must be set. The longitudinal sweeping pole shall be fixed on the vertical pole no more than 200 mm away from the base with right angle fasteners. The horizontal sweeping pole shall also be fixed on the vertical pole close to the longitudinal sweeping pole with right angle fasteners.