Patent ID: 7156645

Claim:
A mold assembly for manufacturing concrete blocks and adapted for use in a concrete block machine, the mold assembly comprising: a plurality of liner plates, each having a major surface, the liner plates configured such that the major surfaces form a mold cavity having a desired form; wherein at least one of the liner plates is moveable; and a gear drive assembly including: a first gear element having a plurality of substantially parallel angled channels and selectively coupled to the at least one movable liner plate; a second gear element having a plurality of substantially parallel angled channels configured to slidably interlock with the angled channels of the first gear element; and an actuator selectively coupled to the second gear element and configured to move the at least one moveable liner plate in a first direction toward an interior of the mold cavity by applying to the second gear element a force in a second direction, which is different from the first direction, causing the second gear element to move in the second direction, and the first gear element and at least one moveable liner plate to move in the first direction toward the interior of the mold cavity, and to move the first gear element and at least one moveable liner plate opposite the first direction away from the interior of the mold cavity by applying to the second gear element a force in a direction opposite the second direction.