A loose-proof spiral spike

A loose-proofing screw is disclose, At least one unload groove is arranged in that middle of the screw thread for blocking the continuous decreasing trend of the whole thread. When the screw body is unde the action of the longitudinal and transverse dynamic loads of the train running, the screw thread pressure of the upper half circle of the tail part is still positive, which is favorable for thread loosening prevention. An unload groove is formed in that middle of the thread, Avoid too many turns of conventional screw threads, The screw thread pressure continuously decreases too much and thewhole thread is easy to loosen, which interrupts the continuous decreasing trend of the whole thread of the conventional screw tack, increases the load on the screw thread of the subsequent thread head greatly, and at the same time, makes the screw thread load distribution on both sides of the unloading groove relatively uniform, so that the screw thread pressure at the tail of the subsequent thread is still very large. 本