Abstract: An automatically inflatable mattress adapted to rest on a bottom of a swimming pool in its deflated position and inflates using compressed air pumped through air inflation lines that are coiled around spring loaded hose reels. A microprocessor actuates a compressed air pump as a person interrupts a signal pattern produced by microwave sensors disposed around the perimeter of the swimming pool. The mattress uniformly rises up to the surface of the swimming pool to catch a distressed individual whose motion is detected after falling into the water.

Abstract: A projectile firing device utilizing a fluid propellant in which an electronic control responsive to a charging signal, cycling of the bolt in the breechblock to a fully closed position and pressure in the firing chamber below a preset value opens a valve to permit pressurized propellant to flow into the firing chamber and closes the valve and enables electronic triggering circuits when the pressure reaches the preset value. The muzzle velocity of the device may be varied by varying the pressure of the propellant in the firing chamber and the rate of fire in the automatic mode may be adjusted electronically. A spring biased injector finger carried by the bolt urges a projectile from a magazine into the bore of the barrel and retains it there to form a gas tight seal until the propellant is ignited. When no projectiles remain in the magazine, the injector finger prevents the bolt from closing completely and therefore inhibits the electronic control from recharging the firing chamber with propellant.