Prevent unloading theftproof bolt

The utility model discloses a prevent unloading theftproof bolt, including bolt head, ring flange, polished rod and screw rod, the ring flange is located between bolt head and the polished rod, is equipped with an axial cotter way on the screw rod, the polished rod lower extreme is equipped with an axial wedge cotter way the same with the axial cotter way. The utility model has the advantages of: the utility model discloses an offer on the polished rod one with the screw rod on the communicating axial wedge cotter way of axial cotter way, the degree of depth of axial wedge cotter way is degressive in proper order along screw rod to ring flange orientation in addition, consequently the theftproof round pin not only can be used in between screw rod and the nut, but also can be used in the polished rod and by between the connecting element to the theftproof function is prevented unloading in the realization. The utility model discloses a bolt head change is compared in common bolt head for the hemisphere, can ef