Disc-type apparatus for crushing hard materials

In an apparatus for crushing hard materials, a housing, a first substantially planar crushing disc supported for rotation in the housing about a first vertical axis, a second substantially conical crushing disc supported in the housing above the first disc for rotation about a second axis oblique to the first axis, the second disc cooperating with the underlying first disc to define a crushing zone therebetween, means for rotating the first disc about the first axis, inlet means supported in a first portion of the housing spaced from the crushing zone for introducing hard material to be crushed onto the first disc to be conveyed downstream through the crushing zone as the first disc rotates, first rake means secured to the housing and disposed in the path of rotation of the first disc downstream of the crushing zone and upstream of the inlet means for diverting material crushed in the crushing zone from the first disc toward the bottom of the housing, and outlet means supported by the housing for discharging crushed material directed toward the bottom of the housing by the first rake means.