Abstract: A liquid dispensing vessel having an air space above the liquid near the top of the vessel has a fluid pump with a suction inlet and a pressure outlet. The pump is operable in a first mode to pump liquid and in a second mode to pump air. There is a first conduit coupling the suction inlet and liquid near the bottom of the vessel, a second conduit coupling the suction inlet and the air space above the liquid near the top of the vessel, a third conduit coupling the pressure outlet to a dispensing device, and a fourth conduit coupling the pressure outlet to liquid near the bottom of the vessel. A valving arrangement is effective to block both the second and fourth conduits for operating the pump in the first mode, and to open the second and fourth conduits for operating the pump in the second mode. The valving arrangement is preferably formed by valves in the second and fourth conduits and an arrangement which is common to the two valves for contemporaneous opening and closing both valves.

Abstract: A fluid pump having a rotary power source, a rotary to reciprocating motion converter in the form of a cam and cam follower, a rotary speed reducing gear train coupling the rotary power source to the rotary to reciprocating motion converter, and no pressure relief bypass is disclosed. The pressure relief function of limiting the fluid pressure within the pumping chambers to predetermined maximum pressures is provided by a pair of springs coupling a pair of opposed diaphragms of a pair of pumping chambers. The springs function as a spring-loaded lost motion coupling which absorbs energy while limiting the pressure in a pumping chamber and releases that stored energy to help power the pump while expelling fluid from the other chamber. The diaphragms are fixed relative to their respective pumping chambers about their outer peripheries and centrally coupled to their respective springs. The diaphragms are normally driven to move in unison, but cease to move in unison when one of the springs yields.

Abstract: A lighting fixture for attachment to the ceiling of public transportation vehicles such as subway cars, buses, aircraft, or the like includes a light transmitting cover assembly which is particularly adapted to retain and back light low cost sheets of advertising material, such as material printed on vellum or thin paper, while also accommodating conventional car cards or transparencies. The fixture further provides a pivotal mounting arrangement along one marginal edge which provides ease of installation with vehicles of varying ceiling contour.