# Peg clutch: sliding pulley driven by a peg on a collar

> What is the simplest clutch?

- Category: Mechanisms › Couplings & joints
- Kind: Hardware
- Basis: Xem Studio design following Brown No. 361 (1868)
- Page: https://xemstudio.com/objects/peg-clutch-mechanism/ · JSON: https://xemstudio.com/api/geometry?object=peg-clutch-mechanism · Plain text: https://xemstudio.com/objects/peg-clutch-mechanism/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- A collar fixed to the shaft carries a peg standing out from its face; a loose pulley beside it carries a matching peg. Sliding the pulley along the shaft (by a fork, not drawn) brings the two pegs into the same plane, the collar's peg catches the pulley's and drives it; sliding it back frees it.
- Drawn engaged: both Ø3 pegs at 5.5 mm radius, 31.65° apart so that they touch (contact only); pegs are Ø3 × 12 dowels projecting 6 mm (the collar's grub screw and the shifting fork are not drawn).
- Brown's No. 361 (pulley clutch by a peg on the shaft and a peg on the pulley). Engages only once per turn and with a shock — a claw or friction clutch is used where that matters.
- Parts (each has its own page): peg-clutch-collar-d16x8-b5, peg-clutch-pulley-d30-b5, linear-shafts-h6, dowel-pins-metric.
- Brown's movement No. 361 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

## Sizes

| parameter | value |
|---|---|
| shaft | Ø5 × 100 |
| collar | Ø16 × 8 |
| pulley | Ø30 face, Ø36 flanges |
| pegs | 2 × Ø3 at r = 5.5 |

## Where the files are

- Henry T. Brown (1868, public domain): [Five Hundred and Seven Mechanical Movements — scan on archive.org](https://archive.org/details/fivehundredseven00browiala) — web — Publisher's page; dimensions are facts
- 507movements.com: [Brown's movement No. 361: figure, his text and an animation](https://507movements.com/mm_361.html) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/peg-clutch-mechanism/index.json · license: https://xemstudio.com/files/hardware/peg-clutch-mechanism/LICENSE.md

- peg-clutch-mechanism-assembly: [STEP](https://xemstudio.com/files/hardware/peg-clutch-mechanism/peg-clutch-mechanism-assembly.step) · [STL](https://xemstudio.com/files/hardware/peg-clutch-mechanism/peg-clutch-mechanism-assembly.stl) — Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)

## Questions

**What is the simplest clutch?**

A collar fixed to the shaft carries a peg standing out from its face; a loose pulley beside it carries a matching peg. Sliding the pulley along the shaft (by a fork, not drawn) brings the two pegs into the same plane, the collar's peg catches the pulley's and drives it; sliding it back frees it.

## Fits with

- [Peg clutch collar Ø16 × 8, Ø5 bore, Ø3 peg hole at 5.5 mm](https://xemstudio.com/objects/peg-clutch-collar-d16x8-b5/)
- [Peg clutch pulley Ø30 face, Ø36 flanges, 14 wide, Ø5 bore, Ø3 peg hole](https://xemstudio.com/objects/peg-clutch-pulley-d30-b5/)
- [Linear shafts Ø3 to Ø25 mm (h6), 100 to 1000 mm long](https://xemstudio.com/objects/linear-shafts-h6/)
- [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/)