Detachable cup head screw

The utility model discloses a detachable half-round head screw, which belongs to the technical field of half-round head screws and comprises a screw cap and a thread part, a screw groove is formed at the top of the screw cap, a protruding part is integrally welded at the bottom of the screw cap, a bottom groove is formed at the bottom of the screw groove towards the inside of the screw cap, and a top block is rotatably connected to the bottom wall of the bottom groove. A movable groove is formed in the bottom of the protruding part, an inner screw rod coaxially connected with the top block is arranged in the movable groove, the inner screw rod is sleeved with a lifting block in a threaded mode, the lifting block is attached to the inner wall of the movable groove, a sinking base is welded to the bottom wall of the lifting block, and an attaching plate is welded to the bottom wall of the sinking base. According to the detachable half-round-head screw, an external small flat-head screw penetrates through the sc