Background art Ground-working, such as excavation, breaking up and cutting with wheel- mounted loaders, tractor excavators or power shovels is performed by suitable working tools being connected to the hoisting and drive systems of the machine.

Each working operation thus requires a special tool, e. g. a shovel of a certain type being connected for digging or a cutter for cutting, etc. This means that between a first cutting operating and a second digging operation the operator must change tools, which is time-consuming and therefore expensive.

Combined tools for contractors'machinery are already known through US 5,405,092, for instance, which shows a crushing tool for earth. In this case an excavator scrapes off an upper layer of earth and this earth is then crushed in the shovel and screened to a finer fraction. The part that cannot be crushed remains in the shovel as a coarse fraction. US 5,485,689 shows a similar crushing tool which is also provided with a movable pressure plate to increase the pressure of the fraction against the crushing rollers.

Both these known tools are limited to crushing material that is picked up by their shovels.

Object of the invention The object of the invention is to provide a device that solves the problem of exchanging tools between various work stages during ground-working.

An additional object of the invention is to enable a work stage to be per- formed by enabling a part-tool to be used separately, i. e. without the other part- tool being active.

The object is also to enable part-tools to be manipulated individually from the cabin of the contractors'vehicle.

Summary of the invention The object of the invention is fulfilled by the invention having acquired the characteristics defined in the claims.

The invention consists of a loading shovel provided with a rotary cutter, permanently or transversely pivotably journalled in the side walls of the loading shovel, i. e. the rotary cutter extends horizontally across the whole width of the

loading shovel. The rotary cutter is motor-driven and can be brought into active engagement with the foundation when the loading shovel is tilted backwards. In an alternative position in one embodiment, active engagement of the rotary cutter can be obtained if the loading shovel is tilted forwards. In all embodiments (not the alternative position), the axis of rotation of the rotary cutter is situated inside the outer limiting surfaces of the loading shovel. Furthermore, the teeth of the ro- tary cutter co-operate with at least one supporting sheet of steel and/or a grid, possibly in the form of rods running in longitudinal direction. The grid may consti- tute an extra accessory. This co-operation applies in all embodiments of the in- vention with the exception of the alternative position.

The invention may also be considered as a rotary cultivator shovel mount- ed on a wheel-mounted loader, for instance, a tractor excavator or a power shov- el. The shovel constitutes a combination between a breaking-up shovel and a cutting unit. The shovel is provided with one or more transverse, roller-shaped cutting member shaped either as a number of axially combined cutting discs or as a roll provided with teeth. The teeth of the cutter co-operate with at least one steel counter-support.

Brief description of the drawings Figure 1 shows a view in perspective of a rotary cutter in accordance with a first embodiment of the invention.

Figure 2 shows a plan view, partially in section, of the cutter tool in accor- dance with an alternative embodiment to that shown in Figure 1, Figure 2a shows a radial section along the line A-A in Figure 2, Figure 3 shows a side view of a rotary cutter operating as a shovel in accor- dance with a second embodiment of the invention, Figure 4 shows a tilted side view of the rotary cutter according to Figure 3, operating as a cutter in opposite direction of movement, Figure 5 shows a side view of an alternative embodiment of the embodiment shown in Figures 3-4.

Description of the invention Figure 1 shows a ground-working tool 11 in the form of a loading shovel 13 provided with side walls 12. The shovel 13 is provided with a cutter 14 pro- vided with teeth 15. The cutter 14 is journalled about a shaft 16 through the side walls 12 of the loading shovel 13. The shovel also comprises a shovel bottom 17, the front edge of which is provided with a steel cutter 18. The shovel also consists of a top 19 and a rear side 20. The rear side is provided with parallel slots 20a through which the teeth 15 of the cutter 14 run upon rotation of the cutter. The

slots 20a extend either across the entire rear side 20 as shown in Figure 1, or over only a limited part of the rear side. The slots thus act as support for the cutter as it rotates. A hydraulic motor 21 is also arranged outside the shovel in order to drive the cutter. The shovel and cutter are thus operated individually from the cabin of the contractors'vehicle. In the embodiment shown here only the teeth of the cutter run through the slots. The top 19 of the shovel is also provided with at- tachment means 22 for attaching the ground-working tool 11 to a contractors'ma- chine.

Figure 2 shows schematically part of a plan view, partially with the cutter removed, of a modification of the invention. The cutter 14 with its teeth 15 is jour- nalled about a shaft 16 in the sides 12 of the shovel. The shaft is connected to a journalling unit 24. Beside the cutter is a rear steel support 25 and a forward steel support 26. This arrangement allows the cutter 14 to be mounted further out through the rear of the shovel. The cutter 14 may even be mounted so that its di- ameter coincides with the level of the rear side. The figure also shows, where the cutter and steel supports have been removed, how a grid 20b with slots 20c may be arranged as an accessory. The figure also shows the hydraulic motor 21 for the cutter 14. Figure 2a shows a section along the line AA in Figure 2. Between the top 19 and bottom 17 of the ground-working tool 11 the rear side 20 is pro- vided with the rear steel support 25 and the forward steel support 26. The grip 20b is mounted outside these steel supports 25,26. The lower side of the steel supports 25,26 is thus at a tangent to the outer periphery of the drum 28 of the cutter 14 and the teeth 15, in the form of cutting knives, pass through notches in the steel supports 25,26 and the slots 20c in the grid 20b, see Figure 2. The grid 20c is secured by special attachment devices (not shown) and is used as an ac- cessory when finer fractions are desired.

Figure 3 shows a side view of a second embodiment of the invention. In this figure the ground-working tool 11 in the form of a cutting shovel operates as loading shovel in the direction indicated by an arrow in the figure, and at the angle of the shovel in relation to the ground, i. e. the rear side 30 of the shovel through which the cutter partially protrudes, forms an angle with the ground so that the cutter is not in contact with the ground. The cutter 31 with its teeth 32 is rotatably journalled in a swinging arm 33 which in turn is pivotably journalled in a flexible mounting 34 in the side wall 35 of the shovel. This embodiment, also, shows an attachment 36 for hoisting gear in a contractors'machine. At the angle to the ground shown in the figure, due to its weight, the swinging arm 33 with cutter 31 rests against a stop member 37 and the cutter is thus in its outermost position, but is still off the ground thanks to the angle of the shovel. In this embodiment as well, the cutter is situated for the most part inside the outer limiting surfaces of the

shovel. This embodiment, also, is provided with forward and rear steel supports, although they are not shown.

Figure 4 shows the embodiment shown in Figure 3 operating as a cutter since the loading shovel has been tilted backwards by its attachments 36 so that the rear side 30 of the shovel is parallel with the ground to be cut. Upon contact with the ground the cutter 31 with its teeth 32 will work its way down by way of a transverse movement in a recess 41 in the side walls of the loading shovel, to a position where the swinging arm 33 rests against the stop member 37. The direc- tion of movement during cutting is backwards, as indicated by the arrow in the figure. Since the swinging arm 33 is journalled in the mounting 34, the cutter 31 is able to give way for obstacles in the surface of the ground. A maximum cutting depth 49 is determined by the placing of the stop member 37. A possible modifi- cation within the scope of the invention is to arrange the stop member movable to enable adjustment of the maximum cutting depth.

Figure 5 shows a modification of the embodiment illustrated in Figures 3- 4, within the scope of the invention. The stop member shown in Figures 3 and 4 has been removed and the swinging arm 53 has been swung downwards and forwards, and connected to one end of a hydraulic cylinder 56 journalled pivotably in the side 55 of the shovel. The other end of the cylinder is pivotably journalled in the swinging arm 53. The outermost position of the piston rod, shown in unbroken lines in the figure, indicates the cutting position. However, this is used with addi- tional forwardly tilted tools than shown in the figure. Cutting is deactivated by the swinging arm 53 being turned to an alternative position, indicated by broken lines in the figure, by activation of the hydraulic cylinder 56. This alternative position represents a position for use of the tool 11 as a shovel.

The embodiments thus show a shovel position and a cutting position that can be set by changing the angle of the tool. Changing between shovel and cut- ting position is achieved by turning the ground-working tool forwards or back- wards about an imagined axis parallel to the axis of the cutter.