# Grooved heart cam (face cam) with roller follower

> Why put a cam groove in the face of a disc?

- Category: Mechanisms › Cams
- Kind: Hardware
- Basis: Xem Studio design following Brown No. 97 (1868)
- Page: https://xemstudio.com/objects/grooved-heart-cam-mechanism/ · JSON: https://xemstudio.com/api/geometry?object=grooved-heart-cam-mechanism · Plain text: https://xemstudio.com/objects/grooved-heart-cam-mechanism/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- 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 groove cut in the face of a disc holds the follower's roller between two walls, so the cam drives it both out and back (positive drive, no return spring). The heart-shaped centre line gives uniform speed: 20 mm out over half a turn, 20 mm back.
- Drawn at 60°: roller centre 26.67 mm from the axis, touching one wall (contact only).
- Brown's No. 97 (grooved heart cam, a variant of No. 96).
- Parts (each has its own page): grooved-heart-cam-r20-h20, roller-follower-10, cam-follower-bar-roller-pin, dowel-pins-metric.
- Brown's movement No. 97 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

## Sizes

| parameter | value |
|---|---|
| groove centre line | R20 → R40 → R20 |
| roller | Ø10 × 4 (roller-follower-10) |
| stroke | 20 mm |
| motion | uniform velocity |

## 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. 97: figure, his text and an animation](https://507movements.com/mm_097.html) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/grooved-heart-cam-mechanism/index.json

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

## Questions

**Why put a cam groove in the face of a disc?**

A groove cut in the face of a disc holds the follower's roller between two walls, so the cam drives it both out and back (positive drive, no return spring). The heart-shaped centre line gives uniform speed: 20 mm out over half a turn, 20 mm back.

## Fits with

- [Grooved heart cam (face cam), uniform motion, 20 mm stroke](https://xemstudio.com/objects/grooved-heart-cam-r20-h20/)
- [Roller follower Ø10 on a Ø3 pin](https://xemstudio.com/objects/roller-follower-10/)
- [Follower bar 8 × 5 with Ø3 roller pin hole (75 mm)](https://xemstudio.com/objects/cam-follower-bar-roller-pin/)
- [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/)