Patent ID: 8002536

Claim:
A concrete block machine comprising: a mold including at least one mold cavity; a feedbox driven back and forth between retracted and extended positions, wherein the feedbox is positioned over a top of the mold deposits concrete in the at least one mold cavity when at the extended position; a cutoff bar coupled to the feedbox and including a moveable cutoff element; and a drive system coupled to the moveable cutoff element, wherein the drive system moves the moveable cutoff element to adjust a distance between the moveable cutoff element and the top of the mold as the feedbox is driven from the extended position to the retracted position such that the moveable cutoff element in a desired fashion in a direction of movement of the feedbox, wherein the drive system comprises: at least one track coupled to a portion of the concrete block machine which is fixed relative to the mold, the at least one track extending in a direction parallel to the direction of movement of the feedbox, wherein a distance between the at least one track and the top of the mold varies in a desired fashion across a length of the track; and a guide mechanism coupled to the moveable cutoff element, wherein the guide mechanism follows the at least one track as the feedbox moves from the extended position to the retracted position so that as the guide mechanism follows the at least one track the guide mechanism varies the distance of the moveable cutoff element from the open top of the mold varies by the distance the at least one track varies from the top of the mold.