US Patent 7938574 Mixing apparatus

A mixing apparatus has a container base and a container lid with the lid carrying a mixing mechanism extending through the lid. The mixing mechanism includes at one end a mixing element and at the other end a drive connection to a drive motor. When the drive is operated, the mixing element mixes the contents of the container, usually with the container inverted. The lid has a rim portion with a circumferential slot, and the top edge of the container is located in the slot when the lid is assembled with the container to improve the connection between the lid and the container during mixing. The lid within the rim portion carries the mixing mechanism and during mixing, the assembly is held to lock the assembly together.