Abstract: Apparatus for comminuting sheet metal or similar material, includes a striking tool rotatably supported about an axis; and an enveloping deck in the form of a grate assembly having holes formed therein or an abrasive plate assembly having depressions formed therein, with the enveloping deck interacting with the striking tool for crushing a material. The holes or the depressions are so arranged as to define a web structure which at least in direction of the axis has a pattern that deviates from a straight line.

Abstract: A protective shield for a hammer-crusher rotor protects at least the circumferential surfaces of disks attached to and rotating with a rotor shaft. In the spacing between neighboring disks, at least one hammer is tiltably or pivotally supported on an axle rod extending at a radial spacing from the shaft through the disks. Each protective shield is formed by at least one filler body made of an especially wear resistant material. The filler bodies are arranged and secured in the free space between neighboring disks where the hammers are not located. In its installed position, each filler body has a radially outwardly facing wear resistant surface having an axial width substantially the same as or slightly wider than the axial gap width of the respective spacing. The radially outer surface of the filler bodies is approximately flush with or concentric to a circumferential outer surface of the neighboring disks.