Abstract: An easy to clean pet litter box is provided, in which pet litter with accumulated dry solid animal waste matter is held in a tray with a perforated bottom. Immediately below, and in sliding contact with the perforated tray bottom, is a flat sheet also provided with identically sized and distributed perforations. The perforations are sized to be larger than typical pet litter granules but small enough to prevent throughflow of animal waste lumps, and are conically chamfered to funnel flow therethrough as well as to scrape off any dried waste encrustations located between the sliding elements. By moving the perforated elements to selectively block off all throughflow (closed mode) to complete congruence of apertures permitting maximum throughflow (open mode) the user sepregates waste matter from reusable pet litter within the litter box. Waste matter is then discarded and the tray put into its closed mode and the litter box turned over to resume operation.

Abstract: A self-leveling instrument mount comprises an instrument table pivotally mounted above a stationary frame on first, second and third vertical support arms. The first support arm is a fixed length member connected to the frame through a ball and socket joint. The second and third support arms are formed of screws extending between the table and frame having effective lengths that are controlled, respectively, by first and second servo motors in response to a pendulum switch to maintain the table parallel to a horizontal reference plane. The pendulum is magnetically damped during operation of the servo motors for stabilization. A mercury switch on the table disables the servo motors when the tilt of the table is too large to be leveled by the support screws.

Abstract: A self-leveling instrument mount comprises an instrument table pivotally mounted above a stationary frame on first, second and third vertical support arms. The first support arm is a fixed length member connected to the frame through a ball and socket joint. The second and third support arms are formed of screws extending between the table and frame having effective lengths that are controlled, respectively, by first and second servo motors in response to a pendulum switch to maintain the table parallel to a horizontal reference plane. The pendulum is magnetically damped during operation of the servo motors for stabilization. A mercury switch on the table disables the servo motors when the tilt of the table is too large to be leveled by the support screws.