Abstract: A method and apparatus for alternately providing and releasing suction to a plurality of pool drains or if desired alternately providing suction and liquid under pressure to pool drains to prevent one from becoming stuck to the drains. This includes introducing a valve arrangement between the drains and the suction pump which is continuously operated to control the flow between the drains and the pump.

Abstract: This invention relates to a novel process with attendant methods and apparatus for testing interlocks on machine barrier guards or equivalent safeguards. The process simulates the breaching of the interlocked safeguard to test the interlock without shutting down the machine operation. Failed interlocks are identified and their status warned against. Furthermore, the associated barrier guards may be physically locked to prevent access to their protected space while allowing normal machine operations until maintenance is practical. The testing process makes possible the reliable interlocking of fixed guards and may be automated to prevent bypassing or sabotage of interlocked safeguarding systems.

Abstract: Noneffervescent pesticidal tablets containing from about 0.1 to about 30 weight percent of a pesticide, from about 0.5 to about 50 weight percent microcrystalline cellulose, from about 5 to about 50 weight percent urea, and from about 0.1 to about 10 weight percent of one or more organic carboxylic acids. The tablets may be packaged in water-soluble film.

Abstract: A wheelchair which can negotiate curbs and other obstructions with a minimum of effort by the wheelchair occupant. The wheelchair has conventional front caster wheels and rear propulsion wheels, with first auxiliary support wheels located between the caster and rear wheels, and second auxiliary wheels being located outboard behind the rear wheels. The castered wheels and the rear wheels are structured to be raised or lowered by the wheelchair occupant. When a curb is encountered, the occupant propels the wheelchair forwardly until the first auxiliary wheels are at the edge of the curb, and the castered wheels are suspended. The castered wheels are then lowered to the bottom of the curb and the wheelchair propelled forward until the second auxiliary wheels are at the curb edge. The large rear wheels are then lowered to curb level, and the wheelchair is propelled by the occupant to the opposite curb, where the curb is ascended by turning the wheelchair 180.degree.