Quick fit revolving connecting unit for connecting a dental instrument to a power supply

A quick fit revolving connecting unit for connecting a dental instrument to a supply unit, said connecting unit including:

• a hose able to be connected to said supply unit and including electric conductors and at least one fluid conduit,
• a fixed portion having a rear end connected to said hose and a front end provided with a group of electric contact rings connected to said conductors, said contact rings being visible on a peripheral surface of said fixed portion to allow an electric connection via revolving contact with the instrument, a set of channels passing through said fixed portion to allow the or each fluid conduit of the hose to communicate with the instrument, and
• a rotating portion rotating freely around said fixed portion and including a coupling sleeve provided with a mechanical coupling device for co-operating with the instrument,
• wherein stop means, allowing said coupling sleeve to rest axially on said fixed portion in a rotatable manner to pull the instrument backwards against the connecting unit, are inserted between said sleeve and said fixed portion, and wherein said coupling sleeve extends forwards over a sufficient length to surround said group of contact rings and to prevent accidental contact between said contact rings and an external object when the connecting unit is not connected to an instrument.