US Patent 10112752 Tumbler lid with reservoir and repetitive measuring and disbursement mechanism

This container lid fits onto existing insulated cups. It has a refillable and sealable reservoir with a top opening to receive substances and a bottom opening to release substances into a container. The release of substances is controlled and measured before release. A double piston and button combination interact with a narrow section of the reservoir to dispense only a portion of the contents from the reservoir into the container. The released portion is carefully metered within the narrow channel when the double piston alternately seals a first opening and a second opening of the narrow channel. The reservoir serves to store the unreleased substance until the next time the button is activated to release addition substance into the container.