PURPOSE: To accurately control the number of oscillations in spite of using an inexpensive commutator motor whose number rotations is fluctuated according to the voltage in mixing the materials by rocking a capsule containing the dental material consisting of powder and liquid.
CONSTITUTION: The pulse of a digital signal can be obtained by a Schmitt trigger 6d outputting a rectangular pulse according to the number of rotations of the driving shaft of or the holder driving shaft of a commutator motor 2. The threshold voltage of the next Schmitt trigger 8 is designed to be produced till the differential final value in the pulse width, and the waveform shaping is performed by the trigger 8 for changing to the rectangular pulse width through a differential circuit 7 with the time constant determined. The analog voltage to be outputted through an integrating circuit 9 passes through a feedback circuit 10 and converted into the voltage corresponding to the outputted voltage. Then, a voltage control circuit 11 imparts the voltage to the rectifier motor 2.
KOBAYASHI AIICHI
OTSUKA YUICHI
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