The present invention relates generally to an improved leak-proof cup. More particularly, the present invention relates to a cup assembly having a cap bearing a drinking spout at one side and an air vent spaced from the drinking spout, with a flow control element frictionally engaged in the vicinity of the drinking spout and air vent to allow passage of liquid out and air in during use, while preventing significant leakage through the spout and vent when not in use.
Enclosed cups having drinking spouts and separate air vents, which allow the user to drink from the spout without creating excessive vacuum in the cup, are known in the art. However, drinking spouts and air vents are liable to leak liquid stored in the cup between feedings, or if dropped during use. Accordingly, certain cups have been developed that use valving mechanisms at the spout and at the air vent. These valves respond to suction generated during feeding to open and allow liquid to pass through the spout and to allow air to enter the air vent when a vacuum is developed in the interior of the cup.
Two patents disclosing such valves are U.S. Pat. No. 5,079,013 to Belanger and U.S. Pat. No. 5,542,670 to Morano, both commonly assigned or licensed to the assignee of the present application. Applicant hereby incorporates the disclosure of those two patents herein by reference. Applicant has on the market a cup that employs a valve assembly similar to that shown in U.S. Pat. No. 5,079,013 that is secured to sleeves in the underside of the cup""s top, but in which the valves are mounted on a single base element. Applicant is also aware of a competitive product having a flow control element of the configuration depicted in FIG. 1, sold as part of the Tumble Mates Spill Proof Cup by the First Years.
Despite the effectiveness of these cup mechanisms, applicant has discovered an improved flow control element and corresponding valve configuration that provides improved fluid flow rates without sacrificing the valve""s resistance to spills or the valve""s durability.
Thus, it is an object of the present invention to provide an improved valve mechanism for a cup assembly that is substantially leak-proof even when upended, dropped or shaken.
It is a further object of the present invention to provide an improved valve mechanism for a leak-proof cup that gives higher fluid flow rates at normal suction forces without sacrificing durability or resistance to spills.
It is a further object of the present invention to provide an improved valve mechanism, cap and cup that are easy to clean and easy to assemble.
Accordingly, the present invention provides a drinking cup assembly including a cup having an open end; a cap adapted to enclose the open end, the cap including a drinking spout and an air vent and mating surfaces adjacent or incorporated into the drinking spout and the air vent; and a flow control valve including two stacks adapted to engage the mating surfaces, each of the two stacks having a concave valve face at a top portion thereof.