Method and apparatus for crushing mineral material

1. A method of crushing a mineral material, comprising the steps of:

delivering the mineral material to a crushing space of a bucket, the bucket forming a supporting frame and including:

side plates;

a lip plate connecting the side plates to one another;

a bottom plate extending therefrom towards a rear part of the bucket; and

a cover plate located opposite the bottom plate, which define therebetween a storage space and the crushing space;

in said crushing space, subjecting the mineral material, by at least one crusher drum provided with crusher blades, to impacts decreasing its particle size, mineral particles having a size meeting a predetermined cross-sectional measure being delivered to be discharged from the crushing space;

while loading the bucket, the mineral material first filling said storage space, the storage space preceding the crushing space;

tilting the bucket such that continuing inclination thereof delivers the mineral material from the storage space towards the at least one crusher drum and at least one transfer and screening drum provided in the crushing space, utilizing gravitational force, the at least one crusher drum and at least one transfer and screening drum extending over an entire cross-section of the crushing space and being arranged on a plane which forms an angle diverging from perpendicular with respect to the bottom plate of the bucket;

separating, in the crushing space, finer particles having a predetermined size from the mineral material currently being delivered to the at least one crusher drum and at least one transfer and screening drum, whereafter rotating motion of the at least one crusher drum and at least one transfer and screening drum provided in the apparatus is started;

delivering the mineral material currently remaining in the crushing space to at least one transfer and screening drum rotated around an axle, which transfer and screening drum moves the material towards the at least one crusher drum, the transfer and screening drum pre-crushing the material, and sufficiently small material fraction having a predetermined diameter may again be discharged;

causing the mineral material to meet the at least one crusher drum which is provided in the crushing space and which is rotated around an axle, whereby the crusher drum, by its crusher blades arranged between discs protruding from the axle of the crusher drum, delivers to at least a portion of the material flow impacts decreasing the particle size of the mineral material, at the same time transferring the mineral material towards a crusher plate while mineral particles having a size meeting a predetermined cross-sectional measure are delivered to become discharged from the crushing space from between the discs; and

causing the mineral material remaining in the crushing space to be subjected, by the crusher blades of the crusher drum, to impacts wedging this mineral material against the crusher plate and decreasing the particle size thereof, mineral particles achieving a size having the predetermined cross-sectional measure being delivered to be discharged from the crushing space.

2. A method as claimed in claim 1 , wherein, in the crushing space, at least a portion of the material flow meets a screen via which mineral particles having a size meeting a predetermined cross-sectional measure are delivered to be immediately discharged from the crushing space.

3. A method as claimed in claim 1 , wherein in the crushing space, the mineral material meets the at least one transfer and screening drum as well as the one crusher drum provided in the crushing space and rotated in the same direction around parallel axles, whereby the transfer and screening drum, by its crusher blades arranged between the discs protruding from the axle of the drum, delivers to at least a portion of the material flow impacts decreasing the particle size, at the same time transferring the mineral material towards the crusher drum while mineral particles having a size meeting a predetermined cross-sectional measure are delivered to be discharged from the crushing space from between the discs of the drums as well as from between adjacent drums.

4. A method as claimed in claim 1 , wherein a position of the crusher plate with respect to the crusher drum is adjusted in order to change the particle size to be achieved in crushing.

5. A method as claimed in claim 1 , wherein the axle of the crusher drum is subjected to the influence of at least one flywheel.

6. An apparatus for crushing a mineral material, the apparatus comprising:

a bucket to be installed in a working machine and constituting a supporting frame, the bucket including:

side plates;

a lip plate connecting the side plates to one another;

a bottom plate extending therefrom towards a rear part of the bucket; and

a cover plate located opposite the bottom plate, which define therebetween a storage space and a crushing space;

crushing means extending over the entire cross-section of the crushing space, the crushing means separating the crushing space from a discharge opening, the crushing means in turn comprising at least one drum provided with crusher blades in order to decrease the particle size of the mineral material delivered to the crushing space, the crusher blades comprising discs protruding from an axle in the drum and crusher blades arranged therebetween, inter-spaces between the discs forming means that enable mineral particles having a size meeting a predetermined cross-sectional measure to be discharged, the crushing means further comprising a crusher plate rotationally connected to the frame of the bucket for receiving the mineral material delivered to the crusher drum and for serving as a counter surface for the crusher blades of the crusher drum;

a storage space in the bucket for receiving the mineral material to be crushed, preceding the crushing space; and

means for separating and discharging a predetermined material fraction from the bucket;

wherein the crushing means are arranged on a plane which forms an angle diverging from the perpendicular with respect to a bottom plate of the bucket.

7. An apparatus as claimed in claim 6 , wherein the drums provided with crusher blades comprise a crusher drum and at least one transfer and screening drum.

8. An apparatus as claimed in claim 6 , wherein the bucket comprises a joint arrangement for connecting the bucket to a working machine, whereby there is a substantially 23 degree angle between the bottom plate of the bucket and said joint arrangement.

9. An apparatus as claimed in claim 6 , wherein the crushing means further comprise a screen for directing mineral particles having a size meeting a predetermined cross-sectional measure to the discharge opening, the outer edge of the screen comprising projections extending to both sides of the crusher blades of the most adjacent drum in order to produce a comb-like structure.

10. An apparatus as claimed in claim 9 , wherein the screen comprises perforations for directing mineral particles having a size meeting a predetermined cross-sectional measure to the discharge opening.

11. An apparatus as claimed in claim 6 , wherein a position of the crusher plate with respect to the crusher drum is adjustable.

12. An apparatus as claimed in claim 6 , wherein the crusher plate comprises wear pieces that are carbide-coated on a side facing the crusher drum.

13. An apparatus as claimed in claim 6 , wherein the number of transfer and screening drums is at least two.

14. An apparatus as claimed in claim 6 , wherein the crusher blades are arranged between discs protruding from the transfer and screening as well as crusher drum substantially equally spaced and in parallel, only one piece in each disc inter-space.

15. An apparatus as claimed in claim 14 , wherein the crusher blades are arranged in the disc interspaces by utilizing a phase shift of 96 to 108 degrees in order to direct a crushing force achieved by the apparatus at only one crusher blade at a time.

16. An apparatus as claimed in claim 6 , wherein the axle of the crusher drum is provided with two flywheels residing at opposite ends of the axle and fastened to the axle of the crusher drum by a friction joint.