AN IMPACT CRUSHER AND AN UPPER ROTOR ASSEMBLY

Abstract

A impact crusher with dual rotor and an upper rotor assembly (50) for the impact crusher are disclosed herein. The upper rotor (30) of the impact crusher comprises two discs on top of each other. The upper rotor (30) comprises a plurality of hammers (40) pointing down, to the outer perimeter of the lower rotor (20) discharging the material to be crushed at high speed. Each hammer (40) has a support shaft (41) that extends vertically between the first disc (31) and the second disc (32). The distance between the first disc (31) and the second disc (32) provides torsional structure to the connection between the hammer and the upper rotor (30). The upper rotor (30) is configured to be tilted into a service position, wherein the service position is tilted between 90 degrees and 180 degrees from a crushing position.

Description

BACKGROUND

This disclosure relates to crusher mills, more particularly to impact crushers having rotary hammers. Vertical shaft impact (VSI) crushers may be used to crush for example rock, mining ore, steel slag for separating metal and slags or various recyclable material. One example of impact crushers comprises dual rotors. The material to be crushed is fed though a hollow vertical shaft leading to central portion of a lower rotor. The lower rotor rotates and accelerates centrifugally the material to be discharged at high speed via the lower rotor openings. The lower rotor may comprise a first hammer at the tip of the lower rotor. One example of VSI crushers comprises multiple fixed anvils at the outer perimeter of the crusher, wherein the accelerated material is thrown against the anvils.

In the dual rotor assembly, the upper rotor rotates to opposite direction about the same axis as the lower rotor. The upper rotor comprises hammers extending downward to receive the accelerated material from the lower rotor. The hammers or fixed anvils face the material being discharged from the lower rotor at high speed providing second impact and further crushing the material.

The upper rotor size may be between 1 and 3 metres. Each hammer may weigh between 10 to 100 kilograms and the upper rotor may rotate at speeds up to 1000 rpm. The upper rotor assembly must withstand the forces from heavy objects impacting the hammers and centrifugal forces pulling the hammers. For these reasons the upper rotor assembly may become heavy in order to be durable.

The crusher has many wearing components that need to be maintained or replaced periodically. Heavy upper rotor assembly may cause maintenance procedures to be difficult. Time consuming maintenance increases the process downtime. Difficult maintenance work may be dangerous to maintenance personnel.

One example of a dual rotor crusher is disclosed in WO2019/141906.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

An impact crusher with dual rotors and an upper rotor assembly for the impact crusher are disclosed hereinafter. The upper rotor assembly is configured to be tilted into a service position, that allows easy access for the maintenance.

The structure of the upper rotor assembly allows tilting the upper rotor into service position. The upper rotor of the impact crusher comprises two discs on top of each other. The upper rotor comprises a plurality of hammers pointing down, towards the outer perimeter of the lower rotor, being configured to receive the accelerated material from the lower rotor to be crushed at high speed. Each hammer has a support shaft that extends vertically between the first disc and the second disc.

The distance between the first disc and the second disc improves structural rigidity of the connection between the hammer and the upper rotor. In the scenario where the support shafts have only single connection to the upper rotor, the single connection point would be susceptible to withstanding the centrifugal force caused by the heavy hammer at the end of the support shaft.

In comparison, the materials used for the first disc and the second disc may be lighter, yet the structure is more durable. The first disc and the second disc form a sandwich structure to the upper rotor.

As the upper rotor assembly is lighter and more durable, it is easier to move. In one embodiment the upper rotor assembly is tiltable to the service position, opening the crusher structure by separating the upper rotor from the lower rotor. The service position is tilted between 90 degrees and 180 degrees from the service position. The service position may be 90 degrees or 180 degrees, wherein the upper rotor assembly may be locked into the service position. This makes maintenance procedures easier, such as replacing wear parts of the hammers. Each hammer assembly may weigh between 30 . . . 100 kilograms, which makes them cumbersome to handle manually. For example, in the 180 degree service position, the upper rotor wear plates and hammer wear parts are easy, fast and safe to replace. The whole upper rotor is easier, faster and safer to remove and reinstall in this position. In the arrangement with 90 degree service position the wear parts may be inserted sideways, thereby reducing the risk of dropping parts inside the upper rotor assembly.

Many of the attendant features will be more readily appreciated as they become better understood by reference to the following detailed description considered in connection with the accompanying drawings. The embodiments described below are not limited to implementations which solve any or all the disadvantages of known crushers.

BRIEF DESCRIPTION OF THE DRAWINGS

The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein

FIG. 1 illustrates schematically a cross-sectional view of one exemplary embodiment of an impact crusher;

FIG. 2 illustrates an isometric view of one exemplary embodiment of a lower rotor;

FIG. 3 illustrates an isometric sectional view of one exemplary embodiment of an upper rotor;

FIG. 4a illustrates an isometric view from above of the same embodiment of the upper rotor;

FIG. 4b illustrates an isometric view from above of the same embodiment of the upper rotor;

FIG. 5 illustrates an isometric view of one exemplary embodiment in a crushing position;

FIG. 6 illustrates an isometric view of one exemplary embodiment in service position of 90°;

FIG. 7 illustrates an isometric view of one exemplary embodiment in service position of 180°;

FIG. 8 illustrates a cross-sectional view of one exemplary embodiment of a hammer assembly;

FIG. 9 illustrates an exploded view of the same embodiment of the hammer assembly; and

FIG. 10 illustrates an exploded view of one exemplary embodiment of the upper rotor.

Like reference numerals are used to designate like parts in the accompanying drawings.

DETAILED DESCRIPTION

The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. However, the same or equivalent functions and sequences may be accomplished by different examples.

Although the present examples are described and illustrated herein as being implemented in a metal slag crusher, they are provided as an example and not a limitation. As those skilled in the art will appreciate, the present examples are suitable for application in a variety of different types of crushers. In this disclosure, directions such as up, down, below or above refer to the impact crusher being in operational, i.e. crushing position.

FIG. 1 illustrates schematically one exemplary embodiment of an impact crusher having a dual rotor assembly. A flow of material 1a to be crushed is received via a funnel 11 to a vertical shaft 10. Non-limiting examples of the material 1a are slags, rock and solid recyclable materials. The vertical shaft 10 is arranged to pass through an upper rotor 30, along its rotational axis 12. The flow of material 1a passes through the upper rotor 30 via the vertical shaft 10.

A lower rotor 20 rotates about the same axis 12 as the upper rotor 30. In this embodiment, the lower rotor 20 and the upper rotor 30 are not physically connected to the same axis 12, therefore there may be minor deviations in their respective rotational axes 12. The upper rotor 30 is rotated by an upper electric motor and the lower rotor 20 is rotated by a lower electric motor. The lower rotor 20 rotates in opposite direction to the upper rotor 30. The lower rotor 20 is configured to receive the material 1a to be crushed from the vertical shaft 10. The lower rotor 20 rotating in the first direction accelerates the flow of material 1b. In one exemplary embodiment the material is accelerated to speeds of 60 . . . 80 m/s. As the material 1a drops through the vertical shaft 10 to the enclosed lower rotor 20 the centrifugal force throws the material 1b against a wear tip 21 configured to the lower rotor 20.

The material 1b discharges from the lower rotor 20 into a plurality of hammers 40. Hammers 40 extend down from the upper rotor 30 to the level of lower rotor's outer perimeter and/or to a position to receive the flow of material being discharged from the lower rotor 20. The upper rotor 30 and the hammers 40 rotate in second direction, thereby enhancing the impact of the material 1b to the hammers 40. After the impact, the material 1c falls from the hammers 40 to be collected outside the impact crusher.

The upper rotor 30 comprises a sandwich structure by having two discs 31, 32 at a distance from each other. Each hammer 40 comprises a wear part 42 and a support shaft 41. The wear part 42 hammers the material 1b. The support shaft 41 connects the wear part 42 to the upper rotor 30. The support shafts 41 are connected from a lower position to the first disc 31. A second disc 32 is above the first disc 31 and the support shafts 41 are connected from an upper position to the second disc 32. In one exemplary embodiment a single hammer 40 weighs 40 kilograms and rotates at 1000 rpm at a 1200 mm radius. Having two vertical support positions allows the hammers 40 and the upper rotor 30 to rotate without deforming under the vigorous conditions of crushing heavy and solid particles. The exemplary embodiment is configured for steel slag with mm particle size and other materials particle size up to 50 mm. An exemplary material processing capacity is 300 tonnes per hour.

FIG. 2 illustrates an isometric view of one exemplary embodiment of the lower rotor 20. The lower rotor 20 is configured to receive the material flow 1a via an opening 21, which is open upwards, facing the hollow portion of the vertical shaft 10. The lower rotor 20 according to the present embodiment comprises three wings 22 leading to discharge openings 23. The opening angle may be between 50° . . . 70°. Diameter of the lower rotor 20 may be 700-1400 mm. The structure of the lower rotor 20 comprises a closed top portion of the wings 22. The wings 22 guide the flow of material 1a to the wide discharge opening 23, which prevents packing or clumping of the material 1b into tight spots or corners. Before exiting though the discharge opening 23 the material 1b may be ejected by a wear tip. In one embodiment the wear tip is replaceable. In one embodiment the wear tip causes an impact to the material 1b.

FIG. 3 illustrates an isometric sectional view of one exemplary embodiment of an upper rotor 30. FIG. 4a illustrates an isometric view of the same upper rotor from above and FIG. 4b from below. The support shaft 41 of the hammer 40 is connected to the first disc 31 and to the second disc 32 according to the sandwich structure of the upper rotor 30. The first disc 31 and the second disc 32 are above the lower rotor 20. The first disc 31, when fully assembled, extends to the vertical shaft 10. The second disc 32, when fully assembled, extends to the vertical shaft 10. The first disc 31 and/or the second disc 32 may be assembled from multiple components, such as sectors. The second rotor 30 may comprise additional support structures, such as a frame supporting the first disc 31 and/or the second disc 32. The distance between first disc 31 and/or the second disc 32 provides two connection points to the support shaft, enabling structural integrity to withstand the centrifugal forces and impacts when crushing the material 1b.

In one alternative embodiment the first disc 31 is connected to the bottom portion of the support shaft 41. In one embodiment the first disc 31 is a hoop or a rim connected only to consecutive support shafts 41. The plurality of hammers 40 are connected towards the axis 12 only via the second disc 32. The first disc 31 may be at the level of the lower rotor 20, supporting the support shafts 41 from below. The first disc 31 is arranged as the hoop, configured to oppose the centrifugal force and to retain the hammers 40 in place, when the upper rotor 30 rotates.

In one alternative embodiment the distance between the first disc 31 and second disc 32 is designed to be smaller as the plurality of hammers 40 are interconnected with the hoop or rim from the bottom portion of the hammers 40. The hoop is in this embodiment an additional component, which may be at the level of the lower rotor 20, supporting the support shafts 41 from below.

In one exemplary embodiment, the upper rotor 30 comprises a plurality of vertical impact bushings 45 between the first disc 31 and the second disc 32. Said impact bushings 45 are configured to receive the support shafts 41 of the hammers 40. The impact bushings 45 may add the structural integrity to the upper rotor 30. In one exemplary embodiment, the support shafts 41 are configured to be pushed through the second disc 32 towards the first disc 31. The support shafts 31 may travel inside the impact bushings. The impact bushings 45 may alleviate the structural tensions.

The structure of the upper rotor 30 is lighter, when compared to flat upper rotor without the sandwich structure. In one exemplary embodiment, the upper rotor 30, and an upper rotor assembly 50, tilt between a crushing position and a service position. FIG. 5 illustrates one exemplary embodiment of the upper rotor assembly 50 in the crushing position, as it is lowered onto the lower rotor 20 and the hammers 40 enter into a closed crushing chamber. The embodiment discloses a maintenance hatch, through which the support shafts 41 may be checked and/or replaced.

The upper rotor assembly 50 comprises a frame for the upper rotor 30 and means for connecting the upper rotor assembly to a lower rotor assembly. The frame FIG. 6 illustrates one exemplary embodiment, having the service position in the upper rotor assembly 50 being tilted 90°. The upper rotor assembly 50 is tilted by arms 60 and hydraulic cylinders 61 along a wide angle joint 62. The wide angle joint 62 is configured to allow the upper rotor assembly 50, and the upper rotor 30, to articulate between the crushing position and the service position. The wide angle joint 62 is one example of an articulated joint. Alternatively, or in addition, the articulated joint may comprise a hinge. The articulated joint allows the upper rotor assembly 50 to be lifted and/or tilted from the lower rotor assembly to the service position, thereby enabling selected components of the dual rotor assembly to be serviced.

In one embodiment, the upper rotor 30 comprises a bearing assembly configured to support the rotatable portions of the upper rotor 30 in various positions: at the crushing position and at the selected service position. These examples are not limiting in terms of tilt angles, as various angles for the service position are possible, depending on the maintenance task. The hammers 40 are in this service positioned horizontally. According to one example, this service position may be beneficial for balancing the upper rotor 30 or tightening the bolts on either side of the upper rotor 30.

FIG. 7 illustrates an isometric view of one exemplary embodiment of the upper rotor assembly 50 in the service position of 180°. The hammers 40 may weigh kilograms. They may be removed or installed via the first disc 31 and fastened by a bolt that is tightened via the second disc 32, below the upper rotor in this service position. Alternatively, the hammers 40 may be removed or installed via the second disc 32.

In one embodiment, the service position is tilted 90 degrees from the crushing position. In one embodiment, the service position is tilted 180 degrees from the crushing position. In one embodiment, the service position may be any position between 90 degrees and 180 degrees. In one embodiment, the service position is locked by locking means between 90 degrees and 180 degrees. In one embodiment, the service position is one position between 90 degrees and 180 degrees. In one embodiment, the service position is one position of between 45 degrees and 180 degrees. In one embodiment, the service position is 180 degrees, a straight angle, or a substantially straight angle. In one embodiment, the service position is one position of between 160 degrees and 200 degrees. In one embodiment, the wide angle joint 62 is configured to limit the angle of the service position. In one embodiment, the wide angle joint 62 is lockable by the locking means to the service position.

FIG. 8 illustrates a cross-sectional view of one exemplary embodiment of the hammer 40 being assembled into the upper rotor 30. FIG. 9 illustrates an exploded view of the same embodiment of the hammer assembly. The upper rotor 30 comprises a plurality of profile shaped openings configured to receive the plurality of support shafts 41. In one embodiment the support shaft 41 is constructed from a steel bar. The steel bar may be cut and machined to shape the support shaft 41. The support shaft 41 comprises a profile shape to match the profile shaped opening. When installing the hammers 40, the orientation or the direction of the wear parts 42 is defined by the shape of the opening and the support shaft 41. In one exemplary embodiment, the profile shaped opening is arranged to the inner surface of the impact bushing 45. The combination of profile shaped openings, impact bushings 45 and shaped support shafts 41 provide increased rigidity to the upper rotor 30, while being lightweight and easy to manufacture.

In one embodiment, the wear parts 42 are replaceable. In one embodiment, the wear part 42 facing the lower rotor 20 is reversibly connected to the support shaft 41. The discharge of material 1b may not be even, most impacts may end up in the lower portion of the wear part. In one embodiment, the wear part 42 is non-reversible. In one embodiment the support shaft 41 comprises at least one vertical groove configured to receive at least one lip of the wear part 42, wherein said groove is configured to hold the wear part 42 laterally in place. The wear part 42 is locked horizontally in place by a collar 43. When installing the wear part 42, it is slid along the vertical groove into the end position or into contact with the first disc 31. The collar 43 is slid according to a horizontal groove 44 configured onto the support shaft 41 into matching slot or other corresponding form configured into the wear part 42. The collar 43 may be fastened into the support shaft 41 by bolts. When reversing the wear part 42, the collar 43 is removed, the wear part 42 slid off the groove. The wear part may be turned upside down and installed back into the support shaft 41. Alternatively, or in addition, the wear part 42 may be connected to the support shaft by a connecting bolt.

The support shafts 41 are tightened from the side of the second disc 32, using a washer and a single bolt. The actual mounting direction may depend on the service position. The hammer assembly is simple and quick to service.

FIG. 10 illustrates an exploded view of one exemplary embodiment of the upper rotor 30. A center piece 46 is configured to be connected to the vertical shaft 10. In one embodiment, the center piece 46 and the vertical shaft 10 are configured to comprise a shape locked connection. The inner surface of the center piece 46 is not perfectly cylindrical, whereas the outer surface of the vertical shaft 10 has a matching shape. The shape locked connection improves the connection and carries at least portion of the stress from the connecting bolts between the center piece 46 and the vertical shaft 10. Between the first ring 31 and the second ring 32 are multiple radial flanges 47, configured to stiffen the upper rotor 30. The radial flanges 45 may reside between each impact bushings 45 or between some of the impact bushings 45. As illustrated in FIG. 8, the impact bushings 45 are arranged between the first disc 31 and the second disc 32. An outer ring 48 covers the inner structure of the upper rotor 30.

An impact crusher is disclosed herein. The impact crusher comprises a vertical shaft configured to receive a flow of material to be crushed; a lower rotor having a vertical axis, configured to receive the material from the vertical shaft and to rotate to a first direction about the vertical axis for accelerating the flow of material; an upper rotor configured to rotate above the lower rotor to a second direction about the same vertical axis; said upper rotor comprising a plurality of hammers extending down to rotate at the level of the accelerated flow of material. An upper rotor assembly comprises the upper rotor; and the upper rotor assembly is connected to the lower rotor assembly comprising the lower rotor by an articulated joint; wherein the upper rotor assembly is configured to be tilted into a service position, along the articulated joint. In one embodiment, the upper rotor assembly is configured to be tilted into the service position between 90 degrees and 180 degrees from a crushing position. In one embodiment, the upper rotor assembly is configured to be tilted into the service position of a substantially straight angle. In one embodiment, the articulated joint comprises a wide angle joint and the upper rotor assembly is tilted by arms and hydraulic cylinders along the wide angle joint. In one embodiment, the upper rotor comprises a first disc; the plurality of hammers comprising a wear part and a support shaft, wherein the support shafts are connected from a lower position to the first disc; and a second disc at a distance above the first disc, wherein the support shafts are connected from an upper position to the second disc. In one embodiment, the support shaft of the hammer is configured to be pushed through the second disc towards the first disc. In one embodiment, the upper rotor comprises a plurality of impact bushings between the first disc and the second disc, configured to receive the support shaft of the hammer. In one embodiment, the upper rotor comprises a plurality of profile shaped openings configured to receive the plurality of support shafts, wherein the support shaft comprises a profile shape to match the profile shaped opening. In one embodiment, the impact crusher comprises multiple radial flanges between the first disc and the second disc. In one embodiment, the support shaft comprises at least one vertical groove configured to receive at least one lip of the wear part, wherein said groove is configured to hold the wear part laterally in place; and wherein the wear part is locked horizontally in place by a collar. In one embodiment,

Alternatively, or in addition an upper rotor assembly for an impact crusher is disclosed herein. The upper rotor comprises an upper rotor; a vertical shaft configured to receive a flow of material to be crushed; wherein the upper rotor is configured to rotate above a lower rotor; and comprising a plurality of hammers extending down to rotate at the level of the accelerated flow of material discharged from the lower rotor. An articulated joint is configured to connect the upper rotor assembly to a lower rotor assembly; wherein the upper rotor assembly is configured to be tilted into a service position along the articulated joint. In one embodiment, the upper rotor assembly is configured to be tilted into the service position between 90 degrees and 180 degrees from a crushing position. In one embodiment, the upper rotor assembly is configured to be tilted into the service position of a substantially straight angle. In one embodiment, the upper rotor assembly is tilted by arms and hydraulic cylinders along a wide angle joint. In one embodiment, the upper rotor comprises a first disc; the plurality of hammers comprising a wear part and a support shaft, wherein the support shafts are connected from a lower position to the first disc; and a second disc at a distance above the first disc, wherein the support shafts are connected from an upper position to the second disc. In one embodiment, the support shaft of the hammer is configured to be pushed through the second disc towards the first disc. In one embodiment, the upper roto comprises a plurality of impact bushings between the first disc and the second disc, configured to receive the support shaft of the hammer; and multiple radial flanges between the first disc and the second disc. In one embodiment, the upper rotor comprises a plurality of profile shaped openings configured to receive the plurality of support shafts, wherein the support shaft comprises a profile shape to match the profile shaped opening.

Any range or device value given herein may be extended or altered without losing the effect sought.

Although at least a portion of the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims.

It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to ‘an’ item refers to one or more of those items.

The term ‘comprising’ is used herein to mean including the elements identified, but that such blocks or elements do not comprise an exclusive list and an apparatus may contain additional blocks or elements.

It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this specification.

Claims

1. An impact crusher, comprising: a vertical shaft configured to receive a flow of material to be crushed;a lower rotor having a vertical axis, configured to receive the material from the vertical shaft and to rotate to a first direction about the vertical axis for accelerating the flow of material;an upper rotor configured to rotate above the lower rotor to a second direction about the same vertical axis;said upper rotor comprising a plurality of hammers extending down to rotate at the level of the accelerated flow of material;wherein the impact crusher further comprises:an upper rotor assembly comprising the upper rotor; andthe upper rotor assembly is connected to the lower rotor assembly comprising the lower rotor by an articulated joint;wherein the upper rotor assembly is configured to be tilted into a service position along the articulated joint.

2. The impact crusher according to claim 1, wherein the articulated joint comprises a wide angle joint and the upper rotor assembly is tilted by arms and hydraulic cylinders along the wide angle joint.

3. The impact crusher according to claim 1 wherein the wherein the service position is tilted between 90 degrees and 180 degrees from a crushing position.

4. The impact crusher according to claim 1 wherein the service position is tilted to a substantially straight angle.

5. The impact crusher according to claim 1 wherein the upper rotor comprises: a first disc;the plurality of hammers comprising a wear part and a support shaft, wherein the support shafts are connected from a lower position to the first disc; anda second disc at a distance above the first disc, wherein the support shafts are connected from an upper position to the second disc.

6. The impact crusher according to claim 1 wherein the support shaft of the hammer is configured to be pushed through the second disc towards the first disc.

7. The impact crusher according to claim 1 wherein the upper rotor comprises a plurality of impact bushings between the first disc and the second disc, configured to receive the support shaft of the hammer.

8. The impact crusher according to claim 1 wherein the upper rotor comprises a plurality of profile shaped openings configured to receive the plurality of support shafts, wherein the support shaft comprises a profile shape to match the profile shaped opening.

9. The impact crusher according to claim 1 characterized in that comprising multiple radial flanges between the first disc and the second disc.

10. The impact crusher according to claim 1 wherein the support shaft comprises at least one vertical groove configured to receive at least one lip of the wear part, wherein said groove is configured to hold the wear part laterally in place; and wherein the wear part is locked horizontally in place by a collar.

11. An upper rotor assembly for an impact crusher, comprising: an upper rotor;a vertical shaft configured to receive a flow of material to be crushed;wherein the upper rotor is configured to rotate above a lower rotor; andcomprising a plurality of hammers extending down to rotate at the level of the accelerated flow of material discharged from the lower rotor;an articulated joint is configured to connect the upper rotor assembly to a lower rotor assembly;wherein the upper rotor assembly is configured to be tilted into a service position along the articulated joint.

12. The upper rotor assembly according to claim 11, wherein the service position between 90 degrees and 180 degrees from a crushing position.

13. The upper rotor assembly according to claim 11, wherein the service position is a substantially straight angle.

14. The upper rotor assembly according to claim 11, wherein the upper rotor assembly is tilted by arms and hydraulic cylinders along a wide angle joint.

15. The upper rotor assembly according to claim 11, comprising: a first disc;the plurality of hammers comprising a wear part and a support shaft, wherein the support shafts are connected from a lower position to the first disc; anda second disc at a distance above the first disc, wherein the support shafts are connected from an upper position to the second disc.

16. The upper rotor assembly according to claim 11, wherein the support shaft of the hammer is configured to be pushed through the second disc towards the first disc.

17. The upper rotor assembly according to claim 11, comprising a plurality of impact bushings between the first disc and the second disc, configured to receive the support shaft of the hammer; and multiple radial flanges between the first disc and the second disc.

18. The upper rotor assembly according to claim 11, comprising a plurality of profile shaped openings configured to receive the plurality of support shafts, wherein the support shaft comprises a profile shape to match the profile shaped opening.