Prestressed cylindrical piezoelectric ultrasonic scaler

Claim 1

An ultrasonic dental scaling tool connectable to an energizing system comprising: an elongated housing, and; a tubular piezo-electric transducer element within said housing responsive to an ultrasonic frequency electric signal for applying ultrasonic frequency vibrations to a replaceable hollow core work tool, and; means mounting said transducer element in said housing and providing for passage of a working fluid through said housing to said hollow core work tool comprising a tubular tension bolt extending axially through said transducer element, one end of said bolt being adapted for connection at a connection point with a hollow core work tool, and the other end being adapted for connection with a source of fluid such that the hollow fluid core of said bolt is communicatable with both the fluid source and the work tool hollow core, a seat on said tension bolt against which one end of said transducer element abuts and a reaction mass of high density material positioned by said bolt and compressively abutting the opposite end of said transducer element such that said transducer element is positioned on said bolt under compression, the transducer element seat being located with respect to the bolt work tool connection point such that a nodal point at the bolt work tool connection is provided, and a dielectric sheath on the bolt outer surface electrically insulating the bolt fluid core from said transducer element; source connection means connected to the housing for effecting connection to a source of a fluid and ultrasonic frequency electricity, and, further connecting means for connecting the hollow core of the bolt and the source connection means and the transducer element to the source connection means for providing a path for the fluid and ultrasonic electrical signal.