How Gideon Sundback Invented the Modern Zipper

The 1917 patent for the separable fastener that perfected the design of the modern zipper using interlocking teeth on two flexible tapes.

What it covers

This patent describes a mechanism for joining two edges of fabric using a series of interlocking teeth mounted on flexible tapes. The device uses a sliding cam, or slider, to force the teeth together when moving in one direction and to pry them apart when moving in the other. By alternating the position of the teeth and using a specific spring-loaded locking mechanism, the fastener ensures that the teeth remain securely engaged even when under tension.

What it doesn't cover

• —Does not cover non-interlocking fasteners like buttons, hooks, or snaps.
• —Does not cover magnetic or adhesive-based fastening systems.
• —Does not cover zippers that use continuous coils instead of individual metal teeth.

The clever bit

The innovation was the precise geometry of the teeth and the slider's internal channels, which allowed for a smooth, reliable engagement that didn't pop open under the natural stress of movement.

Why it matters

Before this design, early attempts at slide fasteners were unreliable and prone to jamming. Gideon Sundback's refinement turned a niche industrial curiosity into a ubiquitous consumer product, fundamentally changing how we manufacture clothing, luggage, and footwear.

Real-world examples

• 1.Standard metal zippers on denim jeans
• 2.Fasteners on heavy-duty canvas bags
• 3.Military-grade gear and field equipment