Interlocking Teeth
Interlocking teeth are the paired metal or plastic components that form the core mechanical element of a zipper. Positioned on opposite edges of two zipper tapes, these teeth are engineered to mesh together when a slider moves along the track. The teeth alternate between left and right sides in a precise sequence, allowing them to interlock in a continuous, overlapping pattern. This interlocking creates the secure closure that makes zippers functional for fastening clothing, bags, and other applications.
Mechanical Design
The effectiveness of interlocking teeth depends on precise engineering of their shape and spacing. Each tooth is typically tapered or wedge-shaped, designed to guide adjacent teeth from the opposite tape into the correct position as the slider passes. The teeth must be uniform in size and positioned at exact intervals to prevent gaps or misalignment. Modern zipper teeth are manufactured through stamping, injection molding, or metal forming processes that ensure consistency across thousands of individual components.
Function and Closure
As the slider moves along the zipper, it forces the interlocking teeth together, creating friction and contact pressure that holds the two tape edges firmly closed. The meshing action is bidirectional—the same mechanism that closes the zipper also opens it when the slider is reversed. The overlapping pattern of left and right teeth distributes stress evenly and prevents individual teeth from bearing excessive load, contributing to the durability and reliability of the zipper closure.
Source Notes
- 2026-04-08: Why are these 3 letters on almost all of my zippers?