blades 25 are designed to have a coarse pitch and a height enabling the materials M that are unfit for crushing to be received within the gaps between the screw blades 25 and pass therethrough without being crushed, while crushing object materials that are to be crushed, such as frame member, etc., as the second crushing roller operates in combination with the third crushing roller 12.
A screw blade 25 is constructed from screw blades 25a and 25b, which are twisted in directions opposite to each other and formed by splitting a single screw into two pieces. The screw blades 25a and 25b are to prevent the object material that is to be crushed from moving sideways at the time of crushing.
The third crushing roller 12 is realized by attaching, as shown in FIG. 10, main screw blades 27 and auxiliary screw blades to a rotary shaft 26. The auxiliary screw blades 28 have a coarser pitch as compared with that of the main screw blades 27, and are twisted in the direction opposite to the main screw blades 27, such that grids "g" are formed between the main screw blades 27 and the auxiliary screw blades 28. The main screw blades 27 and auxiliary screw blades 28 have a height that enables the materials M that are unfit for crushing to be received within these gaps or grids "g" and pass therethrough without being crushed.
The main screw blades 27 and the auxiliary screw blades 28 are constructed from screw blades 27a, 27b, 28a, 28b, which are twisted in directions opposite to each other and formed by splitting respective screws into two pieces each. The opposite directions of twist are to prevent the object material that is to be crushed from moving sideways at the time of crushing.
And, on the discharge side of the casing 3 is provided a conveyor 16.
This conveyor 16, installed at a required inclination, is designed to make the materials M that are unfit for crushing, in massive state without being crushed, tumble from the conveyor 16 after being discharged on the conveyor 16. The conveyor 16 is also designed to move the crus