F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
F16D13/00—Friction clutches
F16D13/12—Friction clutches with an expansible band or coil co-operating with the inner surface of a drum or the like
Outil a moteur a deux vitesses dont le passage d'une vitesse a l'autre est effectue automatiquement par un dispositif a came, tel que perceuses ou analogues