# Leamon Souder's 1903 Design for a Spiral Escalator

> A 1903 patent for a mechanical staircase that moves in a circular, spiraling path to transport people between floors.

- **Patent:** US 723325
- **Original title:** Moving spiral stairway or elevator.
- **Owner:** Individual
- **Granted:** 1903
- **Status:** Public domain (expired)
- **Times cited:** 17
- **Field:** mechanical, automotive

## What it does

The patent describes a mechanical system where steps are mounted on a continuous chain that follows a helical or spiral track. As the chain moves, the steps rise or descend while simultaneously rotating around a central axis. This design intended to save space compared to traditional straight escalators by allowing the stairs to fit into a circular shaft.

## What it does NOT cover

- Does not cover standard linear escalators that move in a straight line.
- Does not cover elevators that use a vertical cable-and-pulley system.
- Does not cover stationary spiral staircases that lack a motorized moving mechanism.

## The clever bit

The innovation lies in the geometry of the track, which forces the steps to maintain a level orientation while navigating a curved, three-dimensional path.

## Real-world examples

1. Spiral escalators found in high-end shopping malls like the ones in the Westfield San Francisco Centre.

## Why it matters

This patent represents an early attempt to solve the problem of vertical transportation in confined urban spaces. While spiral escalators are rare today due to their extreme mechanical complexity and maintenance costs, the concept remains a fascinating niche in the history of civil engineering.

## Frequently asked questions

### What does Leamon Souder's 1903 Design for a Spiral Escalator cover?

A 1903 patent for a mechanical staircase that moves in a circular, spiraling path to transport people between floors.

### Who owns patent US 723325?

Individual owns this patent, granted in 1903.

### 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 723325 cited by?

This patent has been cited by 17 later patents that build on its ideas.

### What problem does this patent solve?

This patent represents an early attempt to solve the problem of vertical transportation in confined urban spaces. While spiral escalators are rare today due to their extreme mechanical complexity and maintenance costs, the concept remains a fascinating niche in the history of civil engineering.

### What does this patent NOT cover?

Does not cover standard linear escalators that move in a straight line.

**Full plain-English explainer:** https://patentbrief.org/patent/us/723325/escalator-moving-stairway

**Original patent:** https://patents.google.com/patent/US723325

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


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [Early Car Wheel Traction Device](https://patentbrief.org/patent/us/1141798/zipper-slide-fastener) — A 1915 patent for a metal device clamped to a car wheel to improve traction on slippery surfaces.
- [Early Roller Coaster Design for Thrill Rides](https://patentbrief.org/patent/us/310966/roller-coaster-thompson) — This 1885 patent describes an early roller coaster structure designed to provide thrilling rides by using gravity and a specific track layout.
- [How Elisha Otis Invented the Modern Safety Elevator](https://patentbrief.org/patent/us/31128/otis-elevator-safety-brake) — An 1861 patent by Elisha Otis describing a mechanism to prevent elevators from falling if their support cables snap.
- [How the Revolving Door Was Invented](https://patentbrief.org/patent/us/387571/revolving-door-van-kannel) — The 1888 patent for the revolving door, designed to keep buildings warm while allowing people to enter and exit easily.
- [How the Slinky Toy Works](https://patentbrief.org/patent/us/2415012/slinky-toy) — The original 1947 patent for the Slinky, a helical spring toy designed to walk down stairs through the transfer of energy.