Stably-fixed hoop

The utility model discloses a stably fixed hoop which comprises an upper hoop body, a lower hoop body is arranged below the upper hoop body, fixing blocks are fixedly connected to the two sides of the bottom of the upper hoop body, clamping grooves are formed in the surfaces of the fixing blocks, and driving boxes are fixedly connected to the two sides of the top of the lower hoop body. When an operator needs to unfix an upper hoop and a lower hoop, the operator rotates a limiting frame by 180 degrees so that the limiting frame can be moved out of the space between a pressing plate and a driving box, then the operator presses the pressing plate so that the pressing plate can move towards the side close to a fixed block, and then a movable frame is driven to move; and the gear is driven to rotate through the teeth, then the clamping frame is driven to move towards the side away from the fixing block, the clamping frame is separated from the clamping groove, then an operator pulls the upper hoop upwards, the fi