Abstract: A mold box changing apparatus for a concrete block molding machine has a roller type mold box feed line, a split female/male thread type attaching/detaching device constituting a tightening mechanism has a lockable rotary support shaft actuated by a cylinder. The tightening mechanism includes a rotary support shaft capable of rotation by a cylinder pierced into a plunger extending downward from the press. A male thread portion has a split engagement groove disposed at a lower end of the rotary support shaft. The male thread portion has an end face in the form of a first inclination surface cam. A female thread portion has a split engagement groove and provided with a second inclination surface cam corresponding to the first inclination surface cam of said male thread portion such that rotation of said rotary support shaft causes the first inclination surface cam to be contacted, under pressure, with the second inclination surface cam.

Abstract: A vibrating apparatus for forming a concrete block by a vibration compaction method. The apparatus has a mold box for contouring a concrete block to be produced, a receiving plate which is detachably and resiliently attached to the bottom of the mold box, a device for vibrating the mold box, and an air spring device which permits a close and resilient contact between the mold box and the receiving plate. This close contact permits the receiving plate to effectively follow the vibration of the mold box. The vibration of the mold box is effectively transmitted to the concrete block material.

Abstract: An improved feeder of a concrete block splitting apparatus which splits a concrete block to form natural looking stone surfaces for gateposts, walls, etc. The feeder has a table which moves in the vertical direction with the concrete block thereon, and receiving members which receive the concrete block when the concrete block is lifted to the predetermined position. The table can be lowered to the original position for successive operations of concrete block lifting while the concrete block is held by the receiving member for the purpose of being fed toward a splitting apparatus.