Apparatus for changing a mold box for a concrete block molding machine

A mold box changing apparatus for a concrete block molding machine, comprising:

• a roller mold box feed line spacedly disposed parallel to the concrete block molding machine,
• a lifter configured to bring a mold box-to-be-changed or a new mold box loadable on a carriage into alignment with a feed plane of the mold box feed line or a plane of the carriage;
• a receiver disposed between opposing rails at a distal end of a feed path portion orthogonal to the mold box feed line and arranged to elevate upward and downward the mold box loaded on the carriage between a predetermined first position and a predetermined second position;
• mold supports disposed at front and back opposite sides of the receiver and arranged to retain a lower surface of the mold box by a rotary shaft support arm supported on a body of the concrete block molding machine;
• and
• a press having a split female/male thread attaching/detaching device projecting from a lower surface of the press for connecting a mold box plunger to the press, which lower surface is located on one side of the concrete block molding machine body,
• the attaching/detaching device having cylinder-actuated lockable rotary support shaft wherein said split female/male thread attaching/detaching device comprises a tightening mechanism, which includes a rotary support shaft extending downward from said press, a male thread portion having a split engagement groove being disposed at a lower end of said rotary support shaft,
• said male thread portion having an end face configured in a first inclination surface cam, a female thread portion on said plunger having a split engagement groove and provided with a second inclination surface cam corresponding to said 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.