Design

## 6.5 The structural heart of the machine

### 6.6 The first production run

# 6.6.1 The factory opens

Let's return to the story of the development of the Brompton. Because Andrew Ritchie could not sell his idea, he decided to set up his own factory to manufacture the bicycles. He borrowed money from friends (the interest on the loans was a bicycle) to build 30 bicycles and 20 for sale.

After the increasing complications of the prototyping stage, manufacturing constraints become a powerful influence on the designer:

> Bending one top tube is difficult enough, bending fifty is really tiring.

> Ritchie (1999)

The main tube was positioned higher and a simpler bought-in offset hinge replaced the purpose-built tube hinges. This forged hinge, which was critical to the Brompton's development, was from France. So, detailed design changes were made to the hingeing system with some benefits to compactness resulting from positioning the hinge higher in the frame.

The telescoping seat pillar was dropped, becoming a single tube, and the frame was braced with a small diagonal cross-beam to give it extra stiffness.

OpenLearn - Design
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