Background of the Invention At present, an apparatus for grinding of materials is known from the patent SU No. 1, 126, 320. This apparatus comprises a cylindrical case enlarging stepwise in the direction downwards and provided with a filling opening. A bottom provided with an output opening is attachable to the case. Three rotors arranged on a driven shaft are situated in this case. Diameters of the rotors are increasing stepwise in the direction to the bottom.

Regularly spaced destruction members are fixed at the circumference of each of the rotors. In a cross-sectional view taken perpendicularly to the rotation plane of the driven shaft, each of the destruction members has the form of the character U, with the bottom of the letter U turned to the axis of rotation of the driven shaft. In each of the arms of the so formed destruction members a system of square spaced through holes is formed. Longitudinal axes of the holes are arranged so that they are mutually parallel and crosswise to the face crushing area of the destruction member. Simultaneously, opposite to the destruction member arm ends, deflectors are provided on the inner cylindrical walls of the case.

It is a disadvantage of this apparatus that it is complicated in design, material demands are high and it is necessary to replace the whole rotor when the damaged destruction members require to be replaced.

Summary of the Invention The above mentioned disadvantages are removed by an apparatus for grinding of materials comprising a cylindrical case provided with a cover attachable to the case, wherein, the cover is provided with a filling opening and the case is provided both with an output opening and a bottom having a rotatably mounted rotor, which rotor is provided with regularly spaced destruction members around its circumference, whereby, each destruction member is provided with a system of through holes, which through holes have their longitudinal axes mutually parallel and transversal to the face incidence area of the destruction member, whereby deflectors are provided on the inner wall of the case, which apparatus is characterized according to this invention in that the destruction member has a length at least three times greater than what is its height and that along this length it is provided with a single line of through holes and/or its surface is dissected, whereby, in a cross section taken along the plane perpendicular to the axis of rotation of this rotor the destruction member has the form of a straight lath.

Further, the apparatus is characterized in that the through holes have the form of a truncated cone in a section taken along their longitudinal axis and in the cross section they have the form of a polygon with n sides, where n is at least 3, or the form of at least a part of a circle or an oval.

Further, the apparatus is characterized in that the destruction member has the form of a polygon with n sides in the cross section, where n is at least 4, or the form of the character I or C or of a shell or the form of at least a part of a circle or an oval, whereby, the deflectors are arranged on the internal surface of the case wall, preferably in places situated above the plane passing through the upper areas or edges of the rotating destruction members and in the cross section taken perpendicularly to the axis of rotation of the rotor they have substantially the form of an airplane wing profile with the upper surface turned towards the rotor. Also, at least one deflector can be arranged on the case cover or on the case bottom.

Finally, the apparatus is also characterized in that the destruction member is mounted in the rotor so that it can swing around an axis, which axis is parallel to the axis of rotation of the rotor.

It is an advantage of this apparatus that it is simple, non- demanding with regard to the materials used and easy to produce.

The destructive member can be easily replaced when damaged.

Brief Description of the Drawings An example of one embodiment of this apparatus for grinding of materials according to this invention is shown in the attached drawings where Fig. 1 shows the first embodiment of the destructive member in a side elevational view, Fig. 2 shows a cross-sectional view taken along the plane A-A as shown in Fig. 1, Fig. 3 shows a side elevational view of the second embodiment of the destructive member, Fig. 4 shows a cross-sectional view taken along the plane B-B as shown in Fig. 3 and Fig. 5 shows a side elevational view of the destructive member with possible design options of the through holes, Fig. 6 shows a cross-sectional view taken along the plane C-C as shown in Fig. 5, Fig. 7 shows a side elevational view of the destructive member with further possible design options how to form the through holes, Fig. 8 shows a cross-sectional view taken along the plane D-D as shown in Fig. 7 and Fig. 9 shows some possible examples of the destructive member shape in cross section.

Fig. 10 shows in side elevational cross-section an embodiment of an independent apparatus for grinding of materials according to this invention, and Fig. 11 shows top plan view of an apparatus for grinding of materials.

Detailed Description of the Invention The apparatus for grinding of materials (see Fig. 10 and 11) comprises a cylindrical case 6 provided with a cover 7 attachable to the case 6. The cover 7 is provided with a filling opening 9. The case 6 is provided with an output opening 8 and a bottom with a rotatably mounted rotor 5, which rotor 5 is provided with regularly spaced destruction members 1 around its circumference.

On its inner end, each destruction member 1 is provided with an opening 4. This opening 4 serves to mount the destruction member 1 by means of a catching element 11 in the rotor 5 so that the destruction member 1 can swing in the rotor 5 around an axis, which axis is parallel to the axis of rotation of the rotor 5. Further, the destruction member 1 is provided with a system of through holes 2. Longitudinal axes of the through holes 2 are mutually parallel and transversal to the face incidence area 3 of the destruction member 1.

In the embodiment according to this invention, the length of each destructive member 1 is seventimes higher then its height and along this length the destructive member 1 is provided with plurality of through holes 2 or the destructive member 1 is dissected on the surface (not shown). The dissected surface of the destructive member 1 means to be provided with protrusions and recesses both on the surface and on the edges. In a cross section taken along the plane perpendicular to the axis of rotation of this rotor 5, the destruction member 1 has the form of a straight lath.

Deflectors 10 are provided on the inner wall of the case 6. The deflectors 10 are situated in places above the plane passing through the upper areas or edges of the rotating destruction members 1. In a preferable embodiment, in the cross section taken perpendicularly to the axis of rotation of the rotor 5, the deflectors 10 have substantially the form of an airplane wing profile with the upper surface turned towards the rotor 5.

Also, the deflectors 10 can be arranged on the cover 7 of the case 6 or on the bottom of the case 6.

In case of the preferable embodiments as shown in Fig. 1 to 8, in a cross section taken along the longitudinal axis of the through holes 2, the through-holes 2 formed in the destruction member 1 have the form of a truncated cone or cylinder, whereby, in the cross section they have the form of a triangle, a square, a rectangle or a circle or of a part of a circle or of an oval or of a part of an oval.

As it can be seen in Fig. 9, it is also preferable if in cross section the destruction member 1 is in the form of a square or a rectangle or if it is in the form of the character I or C or of a shell or of a circle or of a part of a circle or of an oval.