Abstract: A spill-proof lid for use with a container for liquids includes a liquid chamber that has an outlet opening above and an inlet opening below the plane of the lid. The chamber is constructed so that, as it extends from inlet to outlet, it traverses the lid from edge to axially opposing edge and back again. The periphery of the lid is constructed to sealingly engage the upper edge of the container. Preferably, the outlet end of the liquid chamber has a mouthpiece formed thereon for ease of drinking. In one embodiment of the lid, the liquid chamber is substantially a single-loop helix.

Abstract: A spill-proof lid for use with a container for liquids includes a liquid chamber that has an outlet opening above and an inlet opening below the plane of the lid and a vent chamber, which has an inlet above and an outlet below the level of the lid. Each chamber's outlet and inlet ends are adjacent one another. However, the outlet and inlet ends of the vent chamber are on an opposite edge of the lid from the outlet and inlet ends of the liquid chamber. The chambers are constructed so that, as they extend from inlet to outlet, they traverse the lid from edge to axially opposing edge and back again. The periphery of the lid is constructed to sealingly engage the upper edge of the container. Preferably, the inlet end of the vent and the outlet end of the liquid chamber have mouthpieces formed thereon for ease of drinking. In one embodiment of the lid, the liquid and vent chambers are concentric single-loop helixes.