The coffee grinder is an embroidery stitch attachment that is mounted to the back of a 130. It has levers that you can see from the front of the machine and it's housed in a matching black metal unit with the Pfaff logo. It's rather noisy, making a grinding noise -- thus, the name.
This is a good explanation:
https://sites.google.com/site/sewmac...me/pfaff-130-6