Abstract: A sack includes a flexible sack body and a mouth that includes two separable lips that form a mouth opening when the lips are separated from one another, and that close the opening when the lips are adjacent to one another. Closing structure is configured to enable a separating force that is applied to the lips to separate the lips from one another to form the mouth opening, and to bring the lips adjacent to one another to close the mouth opening in the absence of the applied separating force.

Abstract: A carrier includes a chassis that is configured to travel from a loading point to an unloading point and a tillable platform is mounted on the chassis. A resilient piston is connected between the chassis and the tillable platform, the piston configured to store energy when the platform is rotated from an unloading orientation to a loading orientation. The platform, when in the loading orientation, is configured to stably support one or more items that are loaded onto the platform at the loading point. A restraining mechanism is configured to maintain the platform in the loading orientation and a triggering mechanism is operable to release the restraining mechanism, releasing the stored energy of the piston to exert a restoring force to tilt the platform from the loading orientation to the unloading orientation.