Double action disc hog with chip sizing grate

A disc hog for reducing timbers to wood shards of a predetermined maximum size, said disc hog comprising:

• a housing having a front wall and a rear wall joined by a substantially circular ring shaped side wall to form a substantially disc shaped interior cavity of said housing;
• a disc having a front surface and a rear surface and being disposed in said interior cavity of said housing, said disc being mounted on a drive shaft for rotation of said disc about its central axis;
• said front wall of said housing being disposed in spaced substantially parallel relationship to said front surface of said disc and said rear wall of said housing being disposed in spaced substantially parallel relationship to said rear surface of said disc;
• means for driving said shaft to cause said disc to rotate within said interior cavity of said housing;
• a feeder opening formed is said front wall of said housing through which timbers can be introduced into said housing and presented to the front surface of said rotating disc;
• a first plurality of first pulverizing means protruding outwardly from said front surface of said disc with said first pulverizing means being arrayed to impact a timber fed through said feeder opening, said first pulverizing means being configured to cut, shred, or tear the timber into wood chips and shards;
• a plurality of second pulverizing means protruding outwardly from said rear surface of said disc with said second pulverizing means being arrayed to impact wood shards in their vicinity and reduce the shards to chips and shards of a smaller size;
• means for transferring wood shards from the vicinity of said front surface of said disc to the vicinity of said rear surface of said disc for further processing;
• and
• means for expelling wood shards from the vicinity of said rear surface of said disc when the shards are reduced to a predetermined maximum size.