Abstract: A focus mechanism having an actuator positioned near the rear of a handheld piece and that allows a lens element to be moved with respect to a stationary image sensor to achieve a range of focus. When implemented as a manual focusing feature of an intraoral dental camera or handpiece, the focus mechanism allows greater control of focus as the user's hand that grasps the actuator (e.g., ring) is not in close proximity to the distal end of the camera which is inserted into the patient's mouth. Maintaining the image sensor stationary also helps increase system reliability. In a particular embodiment, a variable profile cam allows high precision focus with the camera inside the patient's mouth, while still allowing enough focus travel for capturing a head shot or an image of the patient's smile or face when the camera is moved outside the patient's mouth.

Abstract: A multi-chambered combuster apparatus for the controlled burning of all forms of light combustible organic material and the generation of steam or dry heat energy, resulting in essentially pollution free combustion as atmospheric emissions have zero opacity and low particulate discharge. A primary combustion chamber in which air and fuel are introduced in controlled ratio has interior walls acting as ignition surfaces which also direct combustants in a cyclonic flow path. Combustion gases then expand into a counterflow chamber where cooling and deceleration causes settling of pollutants. The gas stream next enters a purification chamber, passing through a hot filtering medium which entraps any remaining fine particulate matter.