Abstract: The instant invention is a dynamic piezoelectric touch probe for use with coordinate measurement machines. The touch probe is characterized by five subsystems; (1) piezoelectric vibrator controlled by a self-tuning drive circuit that adjusts operating frequency and amplitude, (2) a high sensitivity, resonant accelerometer unit coupled to the piezoelectric vibrator, (3) a flexible suspension/stylus with transverse resonant frequencies tuned to the operating frequency band of the piezoelectric vibrator, (4) a digital control circuit that automatically sweeps the operating band of the piezoelectric vibrator to (a) detect the resonant frequency of the stylus/suspension, (b) set the drive signal frequency at the resonance of the stylus/suspension and (c) control the drive signal amplitude, and (5) a triaxial load cell system that is useful for detecting excessive low frequency suspension/stylus vibration, and excessive impact force during a touch event.

Abstract: Apparatus and method for surgery is disclosed which includes a retractor having a substantially planar base defining an opening for overlying an operative site on a patient, and at least one retractor blade slidably mounted to the base. The base is positioned on the patient such that the opening therein overlies the operative site. The operative site is percutaneously accessed, and obstructing tissue is retracted by engaging the tissue with the retractor blade. A surgical instrument is provided which is engageable with the base and operable at the operative site through the opening in the base. A surgical procedure is carried out through the opening in the base with the surgical instrument.

Abstract: A system and method is disclosed for minimizing residual vibration of a radiographic system due to rapid movement of a radiographic film cassette between a park and expose position. The cassette is moved by a servo system including a servo motor which is responsive to a voltage input waveform to drive the cassette. A waveform is chosen for the voltage input such that no inpulse derivatives appear until the waveform has been diferentiated at least three times. The primary natural resonant frequency of the system is determined and noted. The duration of the selected input waveform is adjusted such that the frequency spectrum of the adjusted input waveform defines a relative null which approximately coincides with the primary resonant frequency. The amplitude of the voltage input waveform is then further adjusted as a function of the distance to be traveled by the cassette between the park and expose positions.

Abstract: A system and method is disclosed for minimizing residual vibration of a radiographic system due to rapid movement of a radiographic film cassette between a park and expose position. The cassette is moved by a servo system including a servo motor which is responsive to a voltage input waveform to drive the cassette. A waveform is chosen for the voltage input such that no impulse derivatives appear until the waveform has been differentiated at least three times. The primary natural resonant frequency of the system is determined and noted. The duration of the selected input waveform is adjusted such that the frequency spectrum of the adjusted input waveform defines a relative null which approximately coincides with the primary resonant frequency. The amplitude of the voltage input waveform is then further adjusted as a function of the distance to be traveled by the cassette between the park and expose positions.