The object of the present invention is a screening, crushing or mixing blade arrangement arranged in the bucket of a working machine, comprising one or more non-circular rotatable shafts and power transmission means for rotating the shafts, wherein each shaft has a plurality of changeable blades freely movable in the lengthwise direction of the shaft mounted thereon, which blades are mounted either directly on the shaft and/or by means of a separate holder, the blades extending in the radial direction of the shaft outward from the shaft, wherein the blades and/or holders are provided with a non-circular mounting hole corresponding essentially to the cross-section of the shaft.

The arrangement according to the invention is suitable for use in connection with e.g., a screen arranged in the bucket of a working machine as presented in the publication DE202006001257 111, which screen is particularly suited for the screening of soil. The working machine may be, e.g., an excavator, a wheel loader, a telehandler, or another suitable moving working machine. The screen has a screening surface with slots, below which there are rotatable shafts with polygonal cross-sections, onto which protruding blades rotating along with the shafts are mounted, which blades extend through the slots in the screening surface to above the screening surface. The blades are movable axially along the corresponding shafts and changeable by dismounting the shafts from the screen and then detaching the changeable blades from the shafts and mounting new blades in place. Figures 1 and 2 show a diagrammatic view of a prior art screening arrangement mounted on the bucket 1 of a moving working machine. The arrangement includes a screening surface 2 arranged in the interior load space of the bucket 1, the screening surface 2 having slots 3 determining the screening roughness. The ends of separate screening plates constituting the screening surface are fixed in place using mounting bars 7 retaining the screening plates at a distance from one another corresponding to the desired screening slot 3. The screening slots 3 extend continuously through the entire distance between the mounting bars of opposite ends of the screening plates, whereby no unnecessary obstacles for the through-flow of material are formed. Behind the screening surface, there are rotatable shafts 4 onto which blades 5 extending outward from the shaft in the radial direction are arranged, which blades 5 extend through the slots 3 of the screening surface 2 in the mounted state of the screen. The shafts are connected to power transmission equipment arranged inside a housing 6 at the side of the bucket 1 for rotating the shafts. The power transmission equipment may be at either side of the bucket 1.

A corresponding screening arrangement is also used in e.g., screen crushers, in which special crushing blades are used, and in mixers, in which special mixing blades are used.

In these prior art solutions, changing the blades requires detaching the shafts from the bucket, which is relatively laborious, as dismounting the power transmission equipment is required before the shaft can be detached from the bucket. This is difficult especially in worksite conditions.

The aim of the present invention is to provide a solution with which the workload required for changing the blades can be significantly reduced and whereby changing the blades can also be carried out in worksite conditions without hoisting aids.

In order to achieve this goal, the arrangement according to the invention is characterized in that the shaft is fitted with at least one thinned section and that the mounting hole for each blade and/or holder has been formed so as to have a discontinuous inner surface by providing it with a mounting aperture opening outward in the radial direction of the mounting hole, which mounting aperture is dimensioned such that the blade can be brought to the shaft at the thinned section of the shaft through said mounting aperture and moved in the lengthwise direction of the shaft to a desired point on the shaft.

Next, the invention is described in more detail with reference to the accompanying drawings, in which:

Figure 1 shows a general principle diagrammatic view of a prior art screening bucket, figure 2 shows the screening bucket according to figure 1 with the screening surface detached, figure 3 shows a general principle diagrammatic view of an embodiment of the arrangement according to the invention viewed from behind in a partially open view, figure 4 shows an enlarged view of a detail of the arrangement according to figure 3 at the blade mounting step, figure 5 shows an enlarged view of a detail of the arrangement according to figure 3 while the blades are mounted in place, figure 6 shows an exploded view of a shaft of the system according to the invention in its one end, and figure 7 shows a diagrammatic view of an embodiment of a screening blade used in the arrangement.

Figures 1 and 2 show a prior art screening bucket arranged in the bucket of a moving working machine, which has been described in more detail hereinbefore in the introduction.

Figure 3 shows a general principle diagrammatic view of an embodiment of the arrangement according to the invention, in which a screening blade assembly arranged on three shafts 4 has been presented. The assembly has been arranged in the screening space 17 between the interior side walls 16a, 16b of the bucket frame. The shafts 4 extend between the said space and further along a portion of their length 4a (figure 6) to the power transmission equipment arranged inside a housing 6. In the embodiment presented, the shaft 4 has been provided with a thinned section 10 with a circular cross-section in the end portion adjacent to the side wall 16a of the shaft 4 on the screening space 17 side. The thinned section 10 can also be formed so as to have a non-circular shape. Figure 3 also shows a mud guard 18, which is described in more detail in the European patent EP2216448B1 in the name of the present applicant. The mud guard can also be left out from the arrangement of the present invention.

Figure 4 shows the arrangement according to figure 3 in a slightly enlarged view. An embodiment of the blade 5 comprised in the arrangement is shown in more detail in figure 7. In the exemplary embodiment presented, the blade 5 is formed as a plate-like screening blade and it is provided with a mounting hole 8 extending in the thickness direction S, the shape of the inner surface 8a of which corresponds to the cross-sectional shape of the shaft 4. The thickness S of the blade 5 is preferably dimensioned so as to correspond essentially to the width of the screening slot 3. It is also possible to arrange two or more blades 5 in parallel in a respectively enlarged slot between two screening plates. The mounting hole 8 has been formed so as to be discontinuous in the direction of the circumference of its inner surface 8a by providing it with a mounting aperture 9 in the radial direction, opening outward, the width W of which aperture is dimensioned such that the blade 5 can be pushed onto the shaft 4 at the thinned section 10. Once the blade 5 has been pushed onto the thinned section 10 of the shaft and the mounting hole 8 is installed so that it is aligned with the outer surface of the shaft 4, the blade 5 can be moved in the axial direction of the shaft 4 to a desired point on the shaft 4.

The cross-section of the shaft 4 and the corresponding shape of the inner surface 8a of the mounting hole 8 have preferably been formed so that the blade and/or blade holder can be positioned in different angular positions in relation to the shaft 4 along the circumferential dimension of the shaft, and the shape is locked in place to resist rotation. If necessary, the blade 5 or blade holder can also be provided with a securing member (not shown) closing the mounting aperture 9, whereby the mounting hole 8 will have a continuous inner surface along the length of its entire circumference ensuring that the blade or blade holder is retained on the shaft.

The thinned section 10 of the shaft 4 can also be used for mounting e.g., spacing pieces or other potentially necessary members on the shaft by providing them with a mounting hole 8 corresponding to that formed onto the blade 5. This can be applied e.g., to an arrangement in which the shaft is fitted with blade holders onto which changeable bits can then be mounted, whereby changing the bits can be carried out without detaching the holders from the shaft. This solution allows for relatively easy changing of the holders to other types of holders, e.g., for changing screening blades to crushing or mixing blades, whereby the range of use of the device is diversified by relatively minor measures. By implementing, e.g., a screening crusher with the holder solution according to the invention, welding the holders onto the shaft of the work drum and potential problems arising therefrom can be avoided.

Figure 5 shows a situation in which the blades 5 are mounted onto the shaft 4 and the thinned section 10 is covered with covering pieces 11a, lib, locked into an end flange 14 shown in figure 6 to be positioned on top of a mounting protrusion 14a arranged on the shaft, locking in place to rotate along with the shaft. The covering pieces 11a, lib are shaped so as to have an outer surface that corresponds to the external shape of the shaft 4, whereby a blade 5 can be positioned on top of them as well.

Figure 6 shows an exploded view of some parts comprised in the arrangement. The outermost end portion 4a of the shaft 4 extends to inside the power transmission equipment. Only the cogwheels 12, bearing 13, and seal 15 are shown of the power transmission equipment and its function and structure are not described in more detail herein.

In the embodiment presented above, the shaft 4 is shown as extending in its end portion 4a to inside the power transmission equipment, whereby dismounting it requires dismounting the power transmission equipment. The shaft can also be made so that it is easier to remove by dimensioning it in such a way that it only extends between the inner surfaces 16a and 16b of the screening space 17 and by providing a shape to the shaft ends that allows for them to be connected to the corresponding end of the drive shaft of the power transmission equipment, whereby the covering pieces 11a, lib act as members locking the shaft and drive shaft to one another.

In addition to above-presented solution fitted with a screening surface, the solution according to the invention is also suitable for applications without a screening surface, such as in the screening, crushing or mixing bucket according to the publication US7913430B2, for example.