Abstract: A gravity-responsive system for securing or restraining the lid or lids of dumping containers in their on-the-ground position and releasing the lid or lids when the container is lifted to its overhead dump position includes a pivotally mounted over-center swingarm that is connected via a connecting link to a lid-restraining bail. When the dumping container is substantially in its on-the-ground position, the bail is rotated to a lid-securing or restraining position in which the lid or lids cannot be opened fully. As the dumping container is lifted toward and to is overhead dump position, the swing-arm rotates in response to gravity to move the bail toward and to a lid-release position to allow the lid or lids to swing away from their closed position to allow the dumping of the contents into the trash truck.