It is well known that wood tailings, more particularly green or dead wood from pruned or felled trees, are used for composting.

To this purpose cutting machines are used, that generally consist of a fixed, mobile or self-propelled container, provided with a hammer crusher cutting the wood tailings into pieces of small size. These known cutting machines however have a plurality of drawbacks.

A first drawback consists in that they only cut the material in the desired size which is then ejected to the outside without being properly mixed.

Consequently the resulting product is rather unhomogeneous.

Another drawback of the known cutting machines is the high noise caused by the high number of revolutions of the rotor supporting the hammers and by the impact of said hammers against the product to be ground.

Another drawback consists of the big absorbed power by the motor actuating the hammer crusher.

Another drawback consists of the big dust cloud dispersed into the environment during the treatment, mainly due to the fan effect of the hammers during rotation.

A last but not least drawback consists of the high maintenance costs that the user is obliged to bear to keep the crusher hammers always efficient.

The present invention aims to overcome said drawbacks.

More particularly a first object of the invention is to provide a cutting-mixing machine carrying out not only the cutting operation of loaded wood tailings, but also mixing the ground product before its ejection.

Another object is to provide a cutting-mixing machine which is less noisy in comparison with similar known cutting machines and having the same productive capacity.

A further object of the invention is a cutting-mixing machine absorbing less power for the same output of product.

Another object is to provide a cutting-mixing machine generating during operation less dust in comparison with the known cutting machines.

A last but not least object is to provide a cutting-mixing machine having less

maintenance costs in comparison with the known cutting machines.

The above mentioned objects are attained by a cutting-mixing machine of wood tailings that according to the main claim comprises: -a container with at least an upper opening for inlet of the material to be treated and at least a side opening for discharging the treated material ; -a conveyor belt for ejecting the treated material, arranged externally to said container at said at least one side opening; -one or more rotating augers provided with blades for cutting said material to be treated and arranged at the bottom of said container, characterized in that said bottom comprises a fixed wall provided with a plurality of first through holes, facing a mobile wall provided with a plurality of second through holes and coupled to driving means adapted to slide the mobile wall relative to said fixed wall in order to intersect said second holes with said first holes and vary the port for the passage of the treated product.

According to a preferred embodiment the first and second holes made in the fixed wall and the mobile wall respectively, have the same diameter and are aligned parallel to the direction defined by the longitudinal axis of the augers.

With a proper displacement of the mobile wall relative to the fixed wall, it is possible to choke the passage port through said holes.

By choking the passage port of the holes it is possible to control the cutting degree and therefore the size of the ground material coming out from the holes by gravity.

The distance between centers of the holes along the aligning direction is at least equal to the double diameter of each hole, so that by moving the mobile wall it is possible to position each hole of said mobile wall between a couple of corresponding holes of the fixed watl, so as to interrupt the flow of outcoming ground and mixed material.

The through holes made in the walls forming the bottom of the container, may concern entirely or partially the surface of the walls in which they are made.

The container may be carried out in a stationary embodiment, an embodiment provided with wheels adapted to be towed by a suitable towing means, or even in a self-propelled embodiment.

Advantageously the cutting-mixing machine of the invention being provided with augers, shows a quieter and more reliable operation in comparison with the conventional cutting-mixing machines provided with hammer crushers.

It is also an advantage of the cutting-mixing machine of the invention to carry out not only the cutting operation but also an optimal mixing of the product before being discharged.

Moreover the presence of holes on the bottom and of the conveyor belt at the side opening of the container, allows to discharge the ground and mixed product both at the bottom and the side of the container.

Finally the possibility to carry out the container in a fixed, towable or self- propelled embodiment gives to the cutting-mixing machine of the invention the maximum versatility.

The above mentioned objects and advantages will be better understood from the description of a preferred embodiment of the invention with reference to the accompanying sheets of drawings in which: -Fig. 1 is a partially sectioned isometric view of the cutting-mixing machine of the invention; -Fig. 2 is a sectioned side view of the cutting-mixing machine of Fig. 1; -Figs. 3 to 5 show different positions of the fixed and mobile wall forming the bottom of the cutting-mixing machine of Fig. 1; and -Fig. 6 shows a different version of the cutting-mixing machine of the invention.

As shown in Figs. 1 and 2 the cutting-mixing machine of the invention generally indicated by reference numeral 1, comprises a container 2 with an upper opening 3 for loading the material to be treated and a side opening 4 for discharging the treated material by means of a conveyor belt 5.

On the bottom 6 of container 2 a couple of rotating augers 7 and 8, respectively, provided with peripheral blades 9,10 for cutting the material to be treated, are preferably but not necessarily arranged.

The rotating augers 7,8 are of the kind known per se which is widely used for cutters mixers of ensiled grass and hay.

Each auger 7,8 consists of a right hand portion 7b, 8a and a left hand portion 7a, 8b axially opposed to each other and symmetrically arranged relative to the center of the container 2 where the side opening 4 is made.

In Fig. 1 both augers 7,8 are shown with a portion of the right part 7a, 8a respectively, removed to allow a better sight of the container bottom 6.

In the constructional embodiment now described this container is made as stationary embodiment provided with supports 2a standing on the ground and

a driving unit generally indicated with. character M to rotate the augers 7,8.

The cutting action on the material loaded into the container 2 is carried out by the blades 9,10 co-operating with stationary counter-blades 11 arranged on the bottom of the container 2. The mixing action of the ground material occurs at the same time of the cutting action by delivering the ground product to the center of the augers along the directions indicated by arrows 12,13 in view of the opposed spirals of each auger.

According to the invention bottom 6 of the container 2 comprises a fixed wall 14 provided with a plurality of first through holes 15, facing a mobile wall 16 provided with a plurality of second through holes 17 and coupled to driving means 18 adapted to slide said mobile wall relative to said fixed wall 14 in order to modify the position of said second holes 17 relative to said first holes 15.

According to the described preferred embodiment, the fixed wall 14 is facing the augers 7,8 while the mobile wall 16 is arranged to the outside of the container 2.

However it is apparent that in a different embodiment the mobile wall may face the augers and the fixed wall may be arranged outside the container 2.

As to the driving means, Fig. 2 shows that they consist of a hydraulic actuator generally indicated with reference numeral 18, comprising a cylinder 19 having its end 19a pivoted to the container 2, a rod 20 sliding inside the cylinder 19 and having its end 20a fixed to the mobile wall 16.

In this way the mobile wall 16 may be moved relative to the fixed wall 14 in a generally horizontal direction according to any direction indicated by arrows 21.

Fig. 1 and Figs. 3 to 5 show that the holes made on the mobile wall 16 and fixed wall 14 are aligned according to directions Xa, Xb, Xc parallel to one another and to the longitudinal direction defined by each axis Ya, Yb of each auger 7,8 respectively.

All the holes 15,17 have the same diameter D and also the same distance between centers I measured along the aligning axes Xa, Xb, Xc.

In this way by imparting to the mobile wall 16 a movement through the hydraulic actuator 18, it is possible to pass from the condition shown in Fig. 3 where the holes 15 and 17 are coincident, to the condition shown in Fig. 5 in which each hole 17 is arranged between a couple of holes 15.

The two conditions shown in Figs. 3 and 5 correspond to the position in which

there is the maximum passage of ground and mixed product and the position in which there is no passage of material at all respectively (the closed holes are shown in broken lines).

It is obvious that different positions of the mobile wall 16 relative to the fixed wall 14 provide for intermediate configurations such as the configuration shown in Fig. 4 in which the holes 15 and 17 are mutually intersected defining the passage ports 22.

On operation when the material is loaded into the container 2, the rotation of augers 7,8 carries out the cutting of the material and at the same time also its mixing by imparting to it the motion indicated by the arrows 12,13 shown in Fig. 1.

An operation mode may for instance provide a first cutting and mixing stage in which the mobile wall 16 is positioned as shown in Fig. 5 with the passage holes closed to allow the complete cutting of the product.

In a subsequent cutting and mixing stage, the mobile wall 16 is moved and the holes are positioned as shown in Fig. 3 so as to discharge the product through the bottom 6 of the container.

Alternatively the side opening 4 may be opened and discharge laterally through the conveyer belt 5.

It is clear that with this operation mode an optimal mixing of the product is obtained, and its size will depend from the cutting time, that is the time in which the augers are being rotated before discharging the product.

Alternatively it is possible to discharge the ground product during the cutting and mixing operation by keeping the holes opened and possibly choking their ports so as to define the partial passage ports 22 shown in Fig. 4, each being of an area less than each hole defining the port.

It is clear that in this way the size of the product will depend from the position of the holes 17 of the mobile wall 16 relative to the holes 15 of the fixed wall 14 and therefore from the size of the partial passage section 22 defined by the hole position.

The cutting-mixing machine of the invention may be carried out according to the constructional versions, one of them being shown in Fig. 6 where the cutting-mixing machine is indicated generally with reference numeral 30 and comprises a container 31 in a transportable version, that is provided with a bridge 32 for coupling with a towing means and wheels 33.

In this case there is a power take off 34 which through suitable motion members transmits to the augers 35,36 the rotation imparted by the engine unit of the towing means.

A further constructional version is also possible in which, as shown also in Fig.

6, the mobile wall indicated with reference numeral 40, concerns only a part of the container bottom.

According to the foregoing description it is to be understood that the cutting- mixing machine of the invention attains all the intended objects in any of its versions.

More particularly the cutting operation through augers is noiseless because the augers rotate at low speed and therefore reduce the impact with the material.

The reduced rotation speed of the augers reduces also the fan effect and generates a limited dust cloud.

Moreover use of augers allows to obtain during the cutting operation, also the mixing of the material.

Finally the low rotation speed of the augers reduces wear of the blades, the maintenance costs and also the power absorption.

Other embodiments may provide for holes of different diameters and different arrangements on the mobile and fixed walls constituting the container bottom.

Moreover said mobile and fixed walls may have one or more zones without holes.

In the constructional stage further constructional variations may also be provided even if not mentioned and described herein before, which should be intended to be falling in the scope of the present invention and of the appended claims.