Abstract: An adjustable filter assembly for a variety of filtration applications. The adjustable filter assembly includes a fixed-size filter medium and frame and an adjustable molding for adjustably applying said filter assembly in applications having widely varying dimensions. The filter assembly can take a variety of shapes and sizes so that any vent may be adequately fitted and filtered. The adjustability of the assembly is accomplished by the molding having at least one adjustable joint enabling the molding to be continuously adjusted from an unextended position through to a fully extended position. In the unextended position, the outside edge of the molding coincides with the perimeter of the filter media and the inner edge of the molding defines a minimum exposed area for the filter medium. In the fully extended position, the inner edge of the molding coincides with the perimeter of the filter media and the outside edge of the molding extends outwardly significantly beyond the perimeter of the filter media.

Abstract: An educational device for simulating the effects of earthquakes includes a table supported above a base by a plurality of coiled springs or other flexible and resilient members. A slot formed in the table coincident with a longitudinal axis of symmetry of the table accommodates a flywheel having a radially extending slot within which is mounted a weight member at any preselected location along the extent of the slot. A battery-operated variable speed motor strapped to the table has an output shaft to which the flywheel is coupled, and a control knob enables a user to vary the speed of rotation of the output shaft and therefore of the flywheel. The intensity of the vibration of the table is varied by moving the weight member along the extent of the radially extending slot. Alternative embodiments include a weight member having a fixed, immovable eccentric position and a balanced flywheel that is mounted eccentrically relative to the output shaft of the motor.