1.  Field of the Invention
The present invention is directed to metered dispensing and, more particularly, to containers with metered dispensing units which are either unistructurally formed as integral thereto or as separate, add on units.  The container is inverted by the user to simultaneously allow liquid to pour out of a dispensing chamber and fresh liquid to pour into a loading chamber of the metered dispensing unit.  When it is uprighted, excessive liquid returns to the main compartment of the container so as to leave a predetermined metered volume of liquid in the loading chamber.  When the cap is put back on, a connecting orifice valve is opened to allow liquid to flow from the loading chamber to the dispensing chamber.  When the cap is removed, the connecting orifice valve is closed and this permits pouring of the metered amount of liquid, with the loading chamber again simultaneously refilling. 
2.  Prior Art Statement
Metered dispensing is an art that has been developed over many decades.  For example, U.S. Pat.  No.  2,038,418 issued in 1936 to B. F. Connor shows a measuring cup located within the neck of a bottle for metered dispensing.  The cup includes two openings, one at the upper side and the other at the bottom, with a valve and stem floating in the bottom opening.  The bottle of Connor is inverted for filling of the cup.  To be used, the bottle must be inverted vertically after the cap is removed to simultaneously pour the liquid in the cup and shut off the main compartment of the bottle.  The Connor device has some limitations that may cause failure.  For example, the bottle would not necessarily shut off the main compartment if tilted at a slant (which is normal for pouring) instead of vertically.  Also, the upper side opening does not close off during pouring and may permit additional liquid flow which would vary depending on how long the bottle is held upside down, thereby causing improper dispensing. 
U.S. Pat.  No.  2,466,085 issued in 1948 to Gronemeyer, et al shows variations in metered dispensing.  For example, a small tube has a flap which is opened by a closed cap; the bottle is inverted for filling the tube; while kept upside down, the bottle cap is partially opened to close off the flap; subsequent removal of the cap permits metered pouring.  However, if the cap is not twisted enough, or too much, either the flap might not close all the way, or the liquid will pour out prematurely.  In one embodiment, FIGS.  5-7, Gronemeyer uses a pliable plastic sac with a predetermined level side slit.  The slit is spread open by a closed cap; the bottle is inverted for filling and uprighted for overflow.  The cap is removed and the slit in the sac closes for metered dispensing.  However, strong sacs may be difficult to open adequately, especially by arthritics taking medicine.  Weaker sacs may wear, rip or break and not close completely.  Further, the closed slit is not sealed by a valve and leakage may occur. 
U.S. Pat.  No.  1,283,050 issued in 1918 to Berg shows a squeeze bottle with a ball valve in the bottle neck below a fixed volume compartment.  A cap extension opens the valve while the cap is closed. 
However, if a user squeezes the bottle to fill the compartment, the cap must be removed immediately, or the bottle kept inverted, to avoid having the compartment liquid return to the main part of the bottle. 
U.S. Pat.  No.  3,402,860 to Torongo describes a squeeze bottle with a chamber which has an elongated bore or inner wall that acts to set volume in the chamber and to limit air or liquid backflow.  Unless a viscous liquid is used and care is taken not to squeeze the bottle during dispensing, surplus dispensing may occur. 
U.S. Pat.  No.  4,376,495, issued in 1983 to W. B. Spatz, describes a complex adjustable dosage metered dispensing system.  An adjustable piston is utilized with a squeeze system whereby the cap has a protrusion which both caps off the tube opening and sets the piston. 
U.S. Pat.  No.  4,830,226 to Kong describes a liquid dispensing apparatus for dispensing a measured amount of liquid from a container which is adjustable for allowing different measured amounts of liquid to be dispensed from the same container.  The apparatus is adaptable for use in the context of two-compartment, squeeze type containers and two-compartment, inversion-type containers and relies upon dual valves with complex internal mechanisms. 
Notwithstanding the prior art discussed above, there has been no teaching of an easily cast, effective, metered dispensing system which operates simply and reliably as does the device of the present invention.