Frequency varying oscillator circuit vibratory cleaning apparatus

Claim 1

An oscillator circuit for sonic and ultrasonic cleaning apparatus comprising: A. a transformer having a primary winding, a secondary winding, and a feedback loop winding; B. a substantially unfiltered rectifier connectable to a source of alternating line current, and delivering direct current pulses to the primary winding of said transformer; C. first capacitance means connected across the primary winding of said transformer; D. a network incorporating a second capacitance means in series with a blocking diode together connected in parallel with said first capacitance means providing differing effective values of capacitance in parallel with said primary winding during positive and negative half cycles of said alternating line current; E. said primary winding, said first capacitance means and said parallel network together presenting non-linear impedance characteristics to said rectifier; F. a piezoelectric transducer connected to said secondary winding of said transformer and also forming part of said cleaning apparatus; and G. switching means connected to the primary winding of said transformer and the feedback loop winding of said transformer, thereby producing a circuit energizing said transducer with a pulse of oscillatory electrical energy having a plurality of different frequency components in response to each direct current pulse delivered to said primary winding, and providing automatic and controllable shifting between low frequency dominance and high frequency dominance during each said pulse.