Patent ID: 7540440

Claim:
A grinding machine comprising a head defining an opening and an orifice plate located within the opening, wherein the orifice plate defines a front surface that lies in a plane, a rear surface, and a peripheral side surface, and wherein the head has at least one recess at the opening and the orifice plate has at least one recess in the side surface, wherein the recess in the side surface of the orifice plate is configured so as not to intersect the plane of the front surface of the orifice plate, and is further configured to define lateral engagement surface spaced rearwardly from the front surface of the orifice plate, wherein the lateral engagement surface is oriented such that at least a portion of the lateral engagement surface extends laterally along the side surface of the orifice plate at a location spaced rearwardly from the plane of the front surface, and wherein the head recess and at least a portion of the orifice plate recess are aligned such that the orifice plate recess is accessible via the head recess to facilitate removal of the plate from the head.