When such prior art airless paint spray equipment is presently used with a painting system

The drive to the piston may take many forms from use of an oscillating crank to the use of a wobble plate as shown in U.S. Pat. No. Re. 29,055 to Wagner, to the use of an eccentric cam wheel drive such as shown in U.S. Pat. Nos. 3,430,557 and 3,623,661 to Wagner, discount oil paintings or other oscillating type connections. Common to all drive connections is the imparting of a reciprocating movement to the hydraulic column drive piston. Normally the drive connection is contained within a housing which forms an oil reservoir for the driving fluid with the cylinder in which the piston reciprocates being provided in a bore through an outside wall of the housing. Such a construction is shown in my prior U.S. Pat. No. 4,022,381 which utilizes an eccentric cam wheel drive.

When such prior art airless paint spray equipment is presently used with a painting system requiring the use of an additional gas source, such as for air surround painting, it is necessary to provide a separate compressed air supply. Since such prior airless paint spray equipment has a distinct advantage of ease of mobility, Oil Paintings airless paint spraying has found wide-spread use in locations where compressed air is not readily obtained. Thus, to use spraying techniques calling for both airless spray painting and air supply, it has heretofor been necessary to bring to the painting site additional equipment for supplying the compressed air.

This can lead to difficulties where the high pressure paint is utilized at a remote spray gun which also utilizes the air. In such situations two separate pressure lines must be provided to the remote gun. To the extent that these two pressure lines originate at different mechanisms, i.e. the paint pump and the air compressor, line entanglement, difficulty in ease of repositioning of the equipment and other disadvantages will occur. It would therefore be an advance in the art to provide a single pumping device which provides separate pressurized liquid and gas streams from a common drive. It would be a further advance in the art if such equipment could be used either for the simultaneous supply of liquid and gas or for the individual supply of liquid or gas.