Crusher, frame of a crusher, and method for manufacturing a frame of a crusher and a crusher

Field of the invention

The invention relates to a crusher according to the preamble of the appended claim 1 , as well as a frame for a crusher according to the preamble of the appended claim 10. The invention also relates to a method for manufacturing the frame for a crusher according to the preamble of the appended claim 18, as well as a method for manufacturing a crusher according to the preamble of the appended claim 24.

Background of the invention

When mineral material is crushed, the material is introduced between two hard surfaces' pressed against each other in a crusher. The crushing force between the surfaces makes the material crumble into smaller particles. There are different types of crushers for different uses and for different mineral and rock types. Typically, cone and gyratory crushers are used for inter- mediate and fine crushing of mineral material, such as rock.

Gyratory crushers, which are normally considered a subtype of cone crushers,, comprise a vertical eccentric shaft with an oblique inner hole fitted inside the frame. A main shaft, to which a supporting cone is fastened, is fitted in the hole. The inner blade is fastened to the supporting cone. The outer blade of the crusher is mounted on the frame of the crusher so that the outer blade surrounds the supporting cone. The inner crushing blade and the outer crushing blade together form a crushing chamber, in which the feed material is crushed. When the crusher is in operation, the eccentric shaft is rotated, wherein the supporting cone is entrained in an oscillating motion and effects variation in the size of the crushing gap between the blades and the crushing of the material in the crushing gap. In the gyratory crusher, the main shaft is further supported at its upper end to the frame by means of an upper supporting bearing.

A suitable crusher type is selected for each crushing process and its different steps. Gyratory crushers are suitable for a variety of crushing processes.

They can be used as intermediate crushers, preliminary crushers, as well as fine crushers. The structure of the crusher is slightly different in the different applications. The structure of a gyratory crusher used as a preliminary crusher is substantially similar to the structure of an intermediate crusher. In the specification and claims herein, the term intermediate crusher also refers to a gyratory crusher used as a preliminary crusher.

In each of the above-mentioned crusher types, the crushing chamber is different. The crusher is formed around an appropriate crushing chamber, and the shape of the crushing chamber will determine the shape and the size of the crushing blade, as well as the method of mounting it on the frame. Thus, the shape of the crushing chamber will also affect the type of frame structure to be used. For this reason, the structures for the frames of the above-mentioned gyratory crusher types are different. The frame of the gyratory crusher consists of at least a lower frame and an upper frame. In a fine crusher, the ^■ lower and upper frames are mounted directly on each other. In an intermediate crusher, an intermediate frame is mounted between the lower and upper ^{• ■} frames. The intermediate frame is thus mounted on both the lower frame and the upper frame. An example of a gyratory crusher that comprises an inter- mediate frame is disclosed in document WO 99/22869. Finnish patent 82393 (to which corresponds US patent 5,152,468), in turn, discloses a crusher that only comprises a lower frame and an upper frame.

Due to the different crushing chambers, the upper frame structures of the gyratory crusher differ from each other. In intermediate and preliminary crushers, the typical crushing chamber is longer and at a more abrupt angle than in fine crushers. For this reason, the mounting of the outer crushing blade on the frame is also different in the different gyratory crusher types. In the fine crusher, the outer blade is mounted on the upper frame of the crusher. In the intermediate crusher, however, the outer blade is mounted on the intermediate frame.

A problem with the frame structure consisting of different frame parts is that the crushing forces, to which the frame is subjected during the crushing, tend to move the different parts of the frame with respect to each other. For this reason, the joint between the frames must be very robust. At present, a rotation of the frames in relation to each other is prevented by a pressed-on fit

which is provided by means of a taper connection using a bolted joint. If the joint is not sufficiently tight due to manufacturing inaccuracies, the bolts of the taper connection must receive both the shearing force caused by the rotation and the tensile load to which they are subjected. This load is too heavy for the bolts and, before long, they will break. As a result, the frames will be detached from each other and they may be even damaged. Also other parts of the crusher may be damaged. Naturally, the crushing will also be interrupted, which will result in economic losses. Furthermore, costs will be incurred by repair and spare parts of the crusher.

Consequently, the size and number of the securing bolts must be increased to secure the grip of the taper connection. This causes extra work in the manufacture of the crusher and increases the price of the crusher. Furthermore, the manufacture of the connection pieces for the frames is difficult work which requires precision. The manufacture of the upper, lower and intermediate frames is normally performed by casting, and the connection

^■ pieces for the frames are integrated in the frames so that they are formed simultaneously when the frames are cast. The different parts for the frame of the crusher, and the connection pieces belonging to them, can also be made to have a plate structure. The connection pieces for the frames must be set quite accurately to achieve a sturdy joint and a robust frame. Even a small inaccuracy in the machining of the taper connection will cause problems when the parts of the frame are connected to each other and the crusher is used.

Furthermore, the assembly of the crusher consisting of different parts is difficult and time-consuming. Moreover, the replacement of crushing blades inside the frame is slow and cumbersome. In connection with the replacement of the crushing blades, a number of bolts securing the frames must be removed and the heavy-duty upper frame structures must be lifted off.

Brief summary of the invention

It is thus an aim of the present invention to provide a crusher which avoids the above-presented problems and whose frame structure is strong and robust.

To achieve this aim, the crusher according to the invention is primarily characterized in what will be presented in the characterizing part of the independent claim 1.

The crusher frame according to the invention, in turn, is primarily characterized in what will be presented in the characterizing part of the independent claim 10.

The method for manufacturing a crusher frame according to the invention, in turn, is primarily characterized in what will be presented in the characterizing part of the independent claim 18.

The method for manufacturing a crusher according to the invention, in turn, is primarily characterized in what will be presented in the characterizing part of the independent claim 24. ^r

The other, dependent claims will present some preferred embodiments of the invention. ^{•■ •■} • - ' ' ^'

The invention is based on the idea that the frame of the crusher consists of a single piece. Thus, the crusher does not comprise separate lower and upper frames and possibly an intermediate frame placed therebetween, but the frame consists of a single piece. The frame is manufactured by casting the whole frame in a single piece, wherein the parts of the frame do not need to be separately mounted on each other. Furthermore, there is no need to manufacture connection pieces for the frame parts, which would be difficult to make.

The frame of the crusher is stronger and more robust than the frame of a crusher assembled according to prior art. The crusher is also easier to assemble, because there is no need for fixing separate pieces of the crusher frame. Moreover, the manufacturing costs of the crusher frame are lower than in crushers of prior art.

The frame of the crusher is designed so that its inner diameter does not become substantially smaller in the upper part of the frame. Preferably, the inner diameter of the frame remains substantially the same, at least in the

upper part of the frame. This kind of a structure makes it possible to replace crushing blades quickly. In connection with the replacement of the crushing blades, only the suspension arm of the top bearing and the feeder hopper are removed, and the blades are replaced from above.

In the gyratory crushers of prior art, for example when the outer crushing blade is replaced, the parts that constitute the frame of the crusher are removed from each other, the frame that comprises the outer crushing blade is lifted off, and the outer crushing blade is replaced therein. The replacement of the inner crushing blade will also require that the frames are removed and lifted off. This takes time, for the removal of the frames from each other is a time-consuming operation. The invention makes it possible to replace the crushing blades from above without needing to remove the frames from each other. ^;

Brief description of the drawings

In the following, the invention will be described in more detail with reference to the appended Figure 1 , which shows a gyratory crusher in a schematic cross section seen from the side.

Detailed description of the invention

Figure 1 shows a gyratory crusher with a frame 1 consisting of a single ele- ment. A feeder hopper 2 is mounted by screw fastening on an annular flange 13 at the upper edge of the frame, to feed mineral material that is to be crushed, into a crushing chamber 10. A first or outer crushing blade 4 is mounted on the frame 1 of the crusher, inside the same. The frame 1 surrounds a main shaft 5 which is bearing-mounted eccentrically on an eccentric shaft 7. The main shaft 5 is supported at its upper end by means of an upper supporting arm 3, which upper supporting arm is mounted at its one end by securing means 6 on a flange 13 at the upper edge of the frame. At its other end, the upper supporting arm 3 is bearing-mounted on the upper end of the main shaft 5. A supporting cone 8 is mounted on the upper end of the main shaft, at a distance from the upper supporting arm 3. A second or inner crushing blade 9 is fastened to the outer surface of the supporting cone 8. The outer crushing blade 4 surrounds the inner crushing blade 9 so that a

crushing chamber 10 is formed between them. When the crusher is in operation, the eccentric shaft 7 is rotated, wherein the supporting cone 8 fastened to the main shaft 5 and the inner crushing blade 9 fastened to the supporting cone 8 are entrained in an eccentric movement which causes variation in the size of the crushing chamber and crushes the material in the crushing chamber. The eccentric shaft 7 is rotated by means of an electrical or hydraulic actuator (not shown in the figures). The drive shaft 14 of the actuator is arranged in the lower part of the frame 1 in such a way that it extends through the frame 1. A piston 15 surrounds the main shaft 5 and the eccen- trie shaft 7 at their lower end. The structure and operation of the crusher are known as such by a person skilled in the art, and therefore, they will not be described in more detail in this context.

As can be seen in the figure, the frame 1 consists of a single solid piece. It does not comprise separate upper, lower or intermediate frames, but the frame is a solid piece surrounding the main shaft 5 and the other parts belonging to the crusher inside the frame. In the vertical direction of the crusher, the frame 1 extends from the level of the lower end of the main shaft

5 to at least the level of the upper part of the crushing chamber 10. Defined more clearly, the frame 1 extends from the level of the lower end of the main shaft 5 to at least the height of the upper surface of the first crushing blade 4. The frame has been designed so that the inner diameter of the frame does not substantially change in the upper part of the frame 1. In this context, the upper part of the frame refers to an area extending a distance downwards from the flange 13 provided at the upper edge of the frame. In particular, the inner diameter of the frame remains unchanged in the part extending from the lower edge of the first crushing blade 4, when mounted, to the upper edge 13 of the frame 1. The frame is cast as a single piece or is made of plate structures.

The main shaft 5 and the eccentric shaft 7 are supported at their lower ends to the lower part of the frame 1. The inner diameter of the lower part of the frame is dimensioned so that a sufficient space is left around the main shaft and the eccentric shaft placed inside it, so that the crushed material can be discharged from the crusher. In Fig. 1 , the inner diameter of the lower part of the crusher is greater than the diameter of the upper part of the crusher. In other words, the crusher becomes wider downwards. If desired, the inner

diameter of the frame of the crusher may also be equal with respect to the whole height of the frame.

The outer crushing blade 4 is mounted on the frame 1 of the crusher by means of a cylindrical mounting piece 11. The mounting piece 11 is divided into several blocks, that is, cylinder sectors. However, the adjacent sectors are connected to each other at the upper part of the mounting piece. The adjacent sectors are separated from each other by a slit extending from the lower part to the upper part of the mounting piece. The mounting piece 11 is locked in place between the frame 1 and the crushing blade 4 by locking means 12. In connection with the replacement of the outer crushing blade, the suspension arm 3 of the top bearing and the feeder hopper 2 are removed, and the blade is replaced from above. Also the inner crushing blade 9 is replaced from above. In connection with the replacement, the outer crushing blade is also removed in addition to the supporting arm of the top bearing and the feeder hopper.

If desired, the outer crushing blade can also be mounted on the frame of the crusher by other types of mounting means than the above-described mount- ing piece 11. However, the above-described mounting piece makes it possible to replace the outer crushing blade quickly, because when the locking means 12 have been fitted in their position during the mounting of the blade, they are also used to lock the mounting piece in its position in the frame of the crusher, and other fastening parts will not be necessary. The locking means required for fastening the blade can be manipulated by a single person, and no crane is needed for their installation. Thus, only two hoistings with a crane are needed during the replacement of the outer crushing blade. What is essential is that the frame is designed so that its inner diameter remains the same at the upper end of the frame, so that the replacement of the outer crushing blade inside the frame can be successfully performed from above.

The invention is not intended to be limited to the embodiments presented as examples above, but the invention is intended to be applied widely within the scope of the inventive idea as defined in the appended claims. The invention is not restricted to the handling of any specific mineral material. The mineral material can be ore, broken rock or gravel, various types of recyclable

construction waste, such as concrete, bricks or asphalt. The invention can also be applied to crushers in which the piston is placed underneath the main shaft only.