Adjustable slotter wheel retrofit apparatus for box blank making machines

Box blank-forming apparatus (60) is provided which includes a feeder assembly (62) and a scoring/slotting assembly (64) each provided with adjustment structure (62a, 64a) to facilitate makeready adjustment of the apparatus (60) between production runs. The feeder assembly (62) preferably includes a reciprocal pusher element (170) operable to successively engage sheets (30) to be formed into box blanks (36). The element (170) is supported by a pair of elongated, threaded, axially rotatable, fore and aft translatable positioning screws (146, 148), so that upon rotation of the screws (146, 148), a reference position of the pusher element (170) may be varied. Adjustment of the assembly (64) is accomplished by means of compensators (292, 294) which are respectively coupled to associated slotter wheel and scoring wheel shafts (288, 286). Operation of the slotter wheel shaft compensator (294) serves to adjust the circumferential positions of the fixed slotter knives (358), whereas operation of the scoring shaft compensator (292) varies the position of the adjustable knives (360) through the medium of transfer gears (384). Servo-sensors (438-442, 446-448 and 270) are used to continuously monitor the lateral and circumferential positions of the scoring/slotting stations (296-304) and a reference position of the pusher element (172), so that precise makeready adjustments can be accomplished.