A device is provided for controlling a discharge of a heavy material from a container such as a bucket, hopper or bin. The device generally includes a combination of gears and levers to couple rotation of a hand wheel or other bar to motion of the release door of a container such that the gears provide a force to the release door which is much greater than that applied to the hand wheel or bar. More specifically, the device may consist of a hand-driven shaft capable of being rotated by a hand wheel or other device. The rotation of this shaft may be coupled by interlocking gears to the rotation of a drive shaft, which is attached to the release door of the container by a lever, such that rotation of the drive shaft causes the release door to open or close, regulating the discharge of concrete or other heavy material from the container.