Abstract: A more efficient reduction mill is described having, with a rotating hammer mill, a readily displaceable grate assembly system entirely pivotally displaced by power means, as a single unit, from the hammer mill portion to achieve ready access to the grate assembly for reversal or replacement of worn sections in combination with a pivotally displaceable by-pass door, which when displaced to a first position permits quick, safe and efficient removal of uncrushable materials from the product stream of the reduction mill without stopping mill rotation. The pivotal displacement of the by-pass door is selectively powered by the same power means or unit which pivotally displaces the grate system for access to the rotor and grate assembly. Such system employing a common power means for selective pivotal displacement of grate system and/or by-pass door permits a more cost-efficient means of achieving size reduction of a variety of materials, and permits also complete and ready access to the rotary hammer mill portion.

Abstract: A more efficient reduction mill is described having a rotating hammer mill portion combined with a grate assembly system employing readily reversible and replaceable grate sections, including reversible and replaceable cutter bar sections forming part of the grate system. The entire grate system is mounted in a side position of discharge with respect to the axis of rotation of the hammer mill and is pivotally disengaged about a lower pivot axis by power means from the hammer mill portion. Ready access to the grate assembly for reversal or replacement of worn sections is thereby achieved. The ease of accessability to the grate assembly, combined with the ease of reversibility and/or replaceability of the various grate sections enables close spacing between the grate assembly and hammer mill to be more readily maintained thereby permitting more efficient reduction of a variety of materials, and more efficient later handling and separation of ferrous from non-ferrous materials.

Abstract: A two-piece hammer for a rotary hammer mill having a separate hammer shank and a separate replaceable hammer tip. The shank and the tip have interlocking portions so that when the two parts are assembled and secured by a transverse pin they form a unitary hammer body that may be mounted on a rotor assembly in a hammer mill used for crushing or shredding materials.