# 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.

- **Patent:** US 1219881
- **Original title:** Separable fastener.
- **Owner:** Hookless Fastener Co
- **Granted:** 1917
- **Status:** Public domain (expired)
- **Times cited:** 14
- **Field:** mechanical, consumer_electronics

## What it does

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 does NOT 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.

## Real-world examples

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

## 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.

## Frequently asked questions

### What does How Gideon Sundback Invented the Modern Zipper cover?

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

### Who owns patent US 1219881?

Hookless Fastener Co owns this patent, granted in 1917.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 1219881 cited by?

This patent has been cited by 14 later patents that build on its ideas.

### What problem does this patent solve?

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.

### What does this patent NOT cover?

Does not cover non-interlocking fasteners like buttons, hooks, or snaps.

**Full plain-English explainer:** https://patentbrief.org/patent/us/1219881/zipper-separable-fastener

**Original patent:** https://patents.google.com/patent/US1219881

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


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