Cam
From NBWiki
Cam 1.
A cam is a round flat disk (top hat style cams are the exception) each having a different profile cut into its outer perimeter, this profile creates embroidery or satin stitch patterns. Cams have either a single or double profile, the second profile controls feed movement.
Cam 2.
A cam used within the mechanics of a sewing machine is usually eccentric in shape having a high and low profile, it is generally mounted on a shaft and is used to drive a mechanical device for example a feed elevation cam.
