Loader movable arm locking device

The utility model relates to a locking device for a movable arm of a loader. U-shaped plate, the U-shaped plate comprises a first flat plate and second flat plates arranged on the two sides of the first flat plate. Supporting plates are fixed to the two ends of the U-shaped plate. The supporting plate is provided with a first opening matched with a piston rod of the movable arm oil cylinder. The U-shaped plate and the supporting plate can be buckled on a piston rod of the movable arm oil cylinder through the first opening; a stop pin can penetrate between the two second flat plates; the stop pin can prevent the U-shaped plate and the supporting plate from falling off from the piston rod of the movable arm oil cylinder, the bending plate is fixed to one end of the U-shaped plate, the bending plate can be connected with the double lug rings at the end of the piston rod of the movable arm oil cylinder in a hanging mode, the lifting state of the loader can be effectively guaranteed throughthe locking device, and