rotator 3 is blocked by the top outer edges of the connecting screw 15 after it is covered on the band shaft joint 2 so that the band shaft joint 2 is joined with the rotator 3 together another connecting way is shown in fig1 and 13 wherein the band shaft joint 2 and the connecting screw 15 are provided with unidirectional teeth 26 engaged with each other at their contact surface employing this structure the rotator 3 will not be detached from the band shaft joint 2 while the rotator 3 could rotator with respect to the joint 2 the unidirectional teeth 26 could make the connecting screw 15 fixedly connected to the joint 2 so as to prevent it loosening in use when in use the band shaft extension end 5 a of the winch is inserted into the cavity 9 of the band shaft joint 2 the corresponding pin holes 2 a and 5 aa on the joint 2 and the band shaft extension end 5 a are aligned then an axle pin 8 is inserted and a driven pin 12 is inserted into the through hole 11 in this way the device provided by the present invention is fixedly connected to the winch in this embodiment.