As the chain belt detached from the state began to mesh with each other, pull zipper slider manufacturer it from the head of an enclosed space (chain from head to body the next opening of upward movement), by the head of the monarch open Angle (pull head on the core of a triangle), chain tooth meshing state change into separate state, thereby releasing chain tooth meshing tooth head, at this point, the shape of the cavity in the head, size and Angle of tooth chain can smooth separate played a important role.The inner cavity of the pullers is in Y shape, divided into three parts: 1, the import or export part, 2, extrusion or release, 3, meshing and stabilization; Pull head due to the internal structure characteristics and functions, pull head shape is not stop shrinking infinity, pull the head of the structure of the three parts, each part of the excessive reduce the probability of the lack of zipper function or quality is not stable.For example: the meshing part of the end of the head, when the length of the two teeth (including the spacing of the tooth) of the chain teeth is shorter than the length of the teeth, the meshing of the chain teeth becomes very unstable. When pull the head of the upper and lower cover plate thickness is thin, can't afford to pull head is in the process of pulling pulling force, make the slider between the upper and lower cover plate spacing, slider’s body upper and lower cover plate convex rib is lost to the chain tooth meshing further reading.in, may cause chain tooth mesh is not in the same horizontal plane, the critical chain phenomenon.