Drinking cups are frequently used with lids that fit on to the cup to reduce the likelihood for accidental spillage of the contents in the cup. Some of these drinking cups are configured so that if they are turned over, liquid inside the cup is prevented from spilling out of the cup through the use of a valve arrangement in the lid.
One type of drinking cup assembly includes a lid having a spout that a child puts his lips on to drink from the cup. The lid attaches (e.g., snaps or screws on) to the cup over an open top of the cup. A valve is arranged in the lid in or upstream from the spout, and the valve opens to allow liquid to flow out of the cup for drinking. Often the valve is actuated by a vacuum pressure applied by the person sucking on the spout. The vacuum pressure is applied to the interior of the cup and moves or deforms the valve in such a way so that the contents of the cup can flow through a drink passage formed in the spout.
Vacuum pressure actuated drinking cup assemblies of this type have problems associated with balancing the need to provide adequate sealing with the desire to have the valve open easily. A strong seal by the valve can require a relatively large vacuum pressure to open the valve. A seal that requires a lower vacuum pressure to open may not seal tightly enough to prevent leakage. Cleaning of cap, the cup and the valve is also important. Disassembly of the valve from the cap should be easy and intuitive.