The present invention relates to a crushing blade arrangement of a crushing drum according to the preamble of claim 1, in which on the outer surface of the crushing drum are arranged a plurality of crushing blades.

Such crushing drums are used, for example, in bucket crushers to be mounted in an excavator or a bucket loader. Fig. 13 shows a crushing drum 30 according to prior art, described in more detail in patent US8074914, including blade elements 32 ar- ranged on an axis 31 and having a strip portion 33 and blade pieces 34. The blade elements 32 are welded to the axis 31 along the entire length of their strip portion 33. The disadvantage of such blade elements fixedly attached to the axis of the crushing drum is their serviceability. As the blade parts wear, the entire drum must be replaced with a new or refurbished drum.

The object of the present invention is to provide an improved crushing blade arrangement, which will substantially facilitate refurbishing work. In order to achieve this object, a crushing blade arrangement according to the invention is characterized in that the receiving space is formed as a substantially quadrangular opening opening onto the upper surface of the blade holder and having on at least one side, extending inwards to the opening, a locking protrusion extending between the bottom surface of the blade holder and its upper surface; and that the shaft portion of the blade piece is shaped substantially quadrangular, corresponding to the opening of the blade holder, and equipped with a longitudinal locking channel corresponding to said at least one locking protrusion and extending towards the interior space of the shaft, which locking protrusion and locking channel together form a form locking.

A solution according to the invention enables fast interchangeability of the blade pieces, wherein it is not necessary to exchange the entire drum for servicing. The blade pieces are further to be turned, substantially increasing their total service life.

In the following, the invention is described in more detail with reference to the accompanying figures, in which: Figs. 1-3 show an embodiment of a blade holder according to the invention dia- grammatically as an oblique isometric view seen from above, as a view seen from the front and as an oblique isometric view seen from below, respectively,

Figs. 4-6 show a blade holder according to Figs. 1-3 as seen directly from below, from the side and from above, respectively, Figs. 7-9 show an embodiment of a blade piece according to the invention dia- grammatically as seen directly from below, from the side and from above, respectively,

Figs. 10-12 show the blade piece of Figs. 7-9 as an oblique isometric view seen from above, as a view seen from the front and as an oblique isometric view seen from below, respectively,

Fig. 13 shows a crushing drum according to prior art. The blade holder 1 shown in Figs. 1-6 includes a frame portion 2, into which is formed a quadrangular opening 3 for receiving the blade piece into it. Two opposite sides of the opening 3 have, extending inwards to the opening, a locking protrusion 5, which extends between the bottom surface 7 of the blade holder and its upper surface, preferably the entire distance from the bottom surface to the upper sur- face. Into the blade holder is further formed a through hole 4, which travels at the locking protrusions 5. To the other two sides of the opening 3, which have no locking protrusion and are opposite each other, is formed to their upper edge an indentation 6 opening onto the outer surface of the blade holder, into which indentation is to be fitted a tool for detaching the blade piece in the holder.

The shaft portion 12 of the blade piece 11 shown in Figs. 7-12 is shaped substantially as corresponding to the opening 3 of the blade holder and equipped on its main surfaces with longitudinal locking channels 15 of the shaft corresponding to said locking protrusions 5 and extending towards the interior space of the shaft, which open onto the lower surface of the shaft, allowing the shaft to be inserted into the opening 3 of the blade holder. The locking protrusion 5 and the locking channel 15 coming opposite to each other together form a form locking. Into the blade piece 11 is also formed a horizontal locking hole 16, which travels substantial- ly at the locking channels 15. The blade pieces are placed into the quadrangular opening 3 by a movement in the direction of the shaft of the blade pieces, i.e. substantially in the direction of the radius of the crushing drum. When the blade piece is in place, the locking holes 4 and 16 in the blade holder settle into alignment and the blade piece can be locked into place by means of a locking element (not shown) extending through the holes. The side surfaces of the shaft portion 12 are preferably shaped as downwardly converging from their upper portion 17a, which facilitates the detaching of a blade piece from the blade holder. The lower portion 17b of the side surfaces is substantially straight. Reference numeral 13 of Figs. 10-12 shows the horizontal portion of the blade piece and reference numeral 14 the front surface forming the work surface.