Tensioner manufacturer is provided with a limit block under the hook on the fixed mold, bonded to the back of the hook. Tensioner supplier second dynamic mode on the threaded connection screw, the other end of this screw fixed mode connection, the drive end of the screw is connected with a hand wheel; using the above scheme, the secondary demoulding is more stable and reliable, while the structure is also very simple, easy to manufacture, installation and maintenance.