Liners for shredding machines

Claim 1

In a reducing machine including a housing having an inlet, a grate in the housing, and a rotor which revolves in the housing above the grate and about a horizontal axes so as to engage material introduced into the housing through the inlet to reduce that material to fragments of smaller size which will pass through the grate, the improvement comprising a liner attached firmly to the housing above the grate and outwardly from the rotor such that it is between the housing and rotor so as to protect the housing from fragments propelled by the rotor, the liner being formed from steel which tends to flow upon being subjected to impacts and having a working surface presented toward the rotor, the liner further having a plurality of grooves which open out of the working surface, the grooves having curved inner ends and further being tapered outwardly from their curved inner ends so that the grooves have their greatest width at the working surface, the depth of each groove being between about 25 and 50 percent of the thickness of the liner at the groove, and the area bordered by two or more grooves being between about 50 in.2 and 400 in.2, whereby the metal of the liner will flow into the grooves as it undergoes plastic deformation and will not create excessive stresses or substantially deform the liner as a whole.