Roller

A Dictionary of Musical Terms · 1895 · p. 18

1. The cylinder or barrel of a music-box, or of a carillon.—2. A roller-board; a wooden bar resting on gudgeons and provided with 2 arms, one pulled by a tracker from a key, which makes the other draw a tracker opening a valve (organ)... Roller-board action, the mechanism belonging to the roller-boards of an organ.