A slider with a locking function needs to be provided with a small window on the top cover of the slider body.The metal zipper position of this small window should be set to avoid the position of the tooth head when the element is in the engaged state,so that the pressure-receiving hook Feet into the teeth of the chain foot space,to lock the slider position.In contrast to the state of meshing of the elements,when the elements are separated,a process from the engagement state to the emancipation state is required,This decomposition force is caused by the angle α and the size of the slider core triangle,When the slider is pulled,the tooth head of the fastener element touches the triangular area of the support core and is forced to open the mouth of the tooth head.Due to width dimension of the slider triangle and the corresponding enlargement of the size of the border state of the slider body cavity.The back of the element,the binding force on the teeth gradually reduced,the tooth began to exit the meshing zone,when the body continued to enter the fastener,the complete elimination of the meshing state of the teeth,in the process,apparently support the core triangle and pull Head side of the state cooperate with each other,the combined effect of the results.