EP2818248A1

EP2818248A1 - Rotary tool for cutting materials and cutting machine comprising such a rotary tool

Info

Publication number: EP2818248A1
Application number: EP14174850.9A
Authority: EP
Inventors: Aldo Tiso
Original assignee: Tierre Srl
Current assignee: Tierre Srl
Priority date: 2013-06-27
Filing date: 2014-06-27
Publication date: 2014-12-31
Also published as: ITPD20130179A1

Abstract

A rotary tool for cutting materials comprises a plurality of disc-like elements which are arranged side by side in the same axis, a plurality of cutting elements which are contained between pairs of disc-like elements opposite each other. There are defined between tangentially contiguous cutting elements respective transport cavities which are opposite a cutting portion of the cutting element and which are capable of receiving the cut material during at least a portion of rotation of the tool.

Description

The present invention relates to a rotary tool for cutting wood and other materials, which are in particular suitable for producing biomass, and a cutting machine comprising such a cutting device.
In the context of the field of agriculture, there are known machines for chopping wood from the pruning of plants and trees.
During pruning, the branches and the shrubs which are cut are allowed to fall on the ground and, for the purpose of reusing the material, that material is collected and cut into small pieces, it further no longer being possible to carry out free combustion on the basis of the currently effective norms. That operation is carried out by means of suitable agricultural machines, typically towed, which collect the wood from the ground by means of rotating vanes, grind the material by means of a rotor which is provided with blades which cooperate with a counter-blade which is fixed to the frame of the machine, finally unloading the cut material towards a discharging section or a collection tank.
The wood chopped up in this manner, which is commonly called "wood chips", may therefore be used as a fuel, or more generally as biomass, or for street furniture, for example, in flower beds or in gardens for covering the ground.
The known machines such as, for example, the one described in the Italian patent IT1370407 , do not provide optimum cutting results in terms of the dimensions of the cut product, producing pieces having very variable dimensions. However, a uniform size would be desirable because it promotes the reuse of the material in bioenergy fields and the compaction of the material in the industrial field.
Another disadvantage of the known machines involves the fact that the moving mechanical elements are subjected to very great forces, this being a result of the chopping of the material substantially during impact between the blades and the counter-blade.
Another example of a machine for cutting wood is described in the international patent application WO 2010/129268 .
The technical problem addressed by the present invention is to provide a machine for cutting material which is structurally and functionally configured so as to allow the disadvantages mentioned above with reference to the prior art to be overcome.
That problem is solved by the rotary tool according to claim 1 and by the cutting machine comprising the tool according to claim 11.
Preferred features of the invention are defined in the dependent claims.
The present invention has some relevant advantages.
The main advantage involves the fact that a sufficiently uniform level of cutting of the material is allowed. Furthermore, the mechanical components used for the cutting action are subjected to forces which are largely contained with respect to the machines constructed according to the prior art.
Other advantages, features and the methods of use of the present invention will become clear from the following detailed description of some embodiments which are set out by way of non-limiting example. Reference may be made to the Figures of the appended drawings, in which:

Figure 1 is a perspective view of a rotary tool for cutting material according to the present invention;
Figure 2 is a front view of the rotary tool of Figure 1;
Figure 3 is a perspective view of a disc-like module which forms the rotary tool of Figure 1;
Figures 4 and 4A are a side view and a relevant detail of the cutting machine for cutting material by means of the rotary tool according to the present invention;
Figure 5 is a perspective view of the machine of Figure 4, without a respective collecting container;
Figure 6 is a perspective view from below of a collecting device, an abutment element and the rotary tool, which are details of the machine of Figure 4;
Figures 6A and 6B are a perspective view and a side view of a deflection grid, respectively, which is a detail of the machine of Figure 4;
Figure 7 is a perspective view which schematically illustrates the main components of a cutting machine for cutting material by means of the rotary tool according to a construction variant;
Figures 8 and 8A are a side view and a respective detail of the cutting machine of Figure 7, respectively;
Figure 9 is a side view of another construction variant of the cutting machine according to the present invention;
Figure 10 is a perspective view of the rotary tool of the cutting machine of Figure 9;
Figures 11A to 11C are perspective views of a disc-like module which forms the rotary tool of the present invention according to additional construction variants;
Figures 12 and 12A are a perspective view and a cross-section of a construction variant of the rotary tool according to the present invention, respectively; and
Figures 13, 14, 15, 16 and 13A, 14A, 15A, 16A are perspective views and cross-sections of additional construction variants of the rotary tool according to the present invention, respectively.

With reference initially to Figure 1, a rotary tool for cutting collected materials, such as, for example, wood from the pruning of hedges, shrubs and trees, is generally designated 1.
It must be understood that, although the description of the present invention makes explicit reference to chopping wood, the tool 1 may also be used for processing a large number of other types of material, such as, for example, plastics material or cardboard. By way of example, the tool 1 may advantageously be used for chopping bottles and, in general, plastics containers for carrying out simple recycling thereof. The tool 1 has a substantially cylindrical form and is advantageously constructed by means of a plurality of mutually adjacent modules, as will be described in greater detail below.
Each module, which is illustrated individually in Figure 3, comprises a pair of disc-like elements 10, between which there are arranged a plurality of cutting elements 2, preferably in the form of inserts.
More specifically, each cutting element 2 extends between the two discs and has a cutting portion 20 which is arranged tangentially relative to the cylindrical surface defined by the disc-like elements 10.
The cutting elements 2 are arranged so as to be angularly staggered relative to each other so that they are distributed, preferably in a uniform manner, over the circumference of the disc-like elements 10. For example, as may be seen in the Figures, each module supports eight disc-like elements 10. The disc-like elements 10 are formed as a single body and are substantially flat-shaped. This feature makes the construction and assembly thereof particularly simple as will be illustrated in greater detail below.
According to a preferred embodiment, the disc-like elements 10 have notches in the region of the outer diameter thereof so as to define respective seats which are suitable for receiving the cutting elements 2.
Furthermore, the cutting elements 2 are advantageously fixed in a removable manner in the region of those seats, for example, by means of a screw which is received in a corresponding nut or by means of a bolted connection. It is further evident that, although the present embodiment makes use of a single screw, there could be used two mutually adjacent screws in the case of cutting elements having greater dimensions.
In addition, according to a preferred embodiment, the cutting elements have a cross-section with respect to the rotation direction of the cutting element in the form of a trapezium. In that manner, there is defined an upper face of the cutting element in which it is possible to define a seat, which is preferably flared, for receiving the screw.
With reference to Figure 3, therefore, the disc-like elements 10 are preferably of annular form with a variable outer diameter. More specifically, the extent of the diameter of those rings is such that a portion of the ring 11 which is opposite the cutting portion 20 of the cutting element 2 is arranged in a radially lower position with respect to the cutting portion 20 itself. However, a second ring portion 12 which is opposite an end 21 which is opposite that cutting portion 20 is radially aligned with that end 21. The transition between the ring portion 11 which faces the cutting portion 20 and the second ring portion 12 which faces the end 21 opposite the cutting portion 20 is preferably produced in a gradual manner.
According to a preferred embodiment, each disc-like element 10 has connection means 13 with respect to a drive shaft which is not illustrated in the Figures and which allows the rotor to be rotated.
In this manner, each disc-like element is supported by means of the drive shaft, conferring greater stability and strength on the rotor generally.
Preferably, the connection means 13 are produced by means of a dimensional connection or a form-fitting connection or a combination of the two.
In the present embodiment, each disc-like element has in the region of the internal peripheral portion thereof respective recesses which are intended to be connected to relevant projections on the drive shaft. It is evident that it would also be possible to provide for the transposed solution with projections on the disc-like element and recesses in the shaft.
Again with reference to Figure 1, there are further defined in the rotary tool 1 transport cavities 3 which are arranged between two successive cutting elements 2.
The chambers 3 are opposite the cutting portion 20 of the cutting element 2. Furthermore, the cutting portion 20 of the cutting element 2 preferably projects into the transport cavity 3.
In this manner, as will be illustrated more clearly below, when the cutting portion 20 acts on the material, bringing about the cutting thereof or generally the breaking thereof, the portion of cut material is collected in the cavity 3. Furthermore, the gradual transition of the disc-like elements described above allows the collection inside the above-mentioned recesses to be optimized.
The transport cavities 3 allow establishment of the dimensions of the cut material by the rotary tool, in the specific case constituted by the wood chips.
In fact, only portions of material which have dimensions smaller than those of the transport cavity 3 which may be represented by the length, width, depth or the diagonal development, in accordance with the orientation of the material portion, may be received in the transport cavities. It is further evident that by varying those dimensions of the transport cavities it is possible to select the dimensions of the material processed by the rotary tool 1.
The cut material remains accommodated inside the collecting recesses during at least a portion of the rotation of the tool 1 about the rotation axis X thereof which is coincident with the axis of the cylinder and the disc-like elements 10.
In order to optimally accommodate the cut material, the transport cavity 3 is defined by a base surface 30 which extends between two cutting elements 2 which are tangentially adjacent.
The base surface 30 is preferably defined by means of an annular member 31 which is arranged so as to be coaxial relative to the disc-like elements 10 and interposed between two of them. On the annular member 31 there alternate projecting portions 32 to which the cutting elements 2 are detachably fixed and recessed portions 33 which are capable of defining the base surfaces and the relevant transport cavities 3 in association with the disc-like elements between which the annular member 31 is arranged.
The annular member 31 may also be constructed by means of a single member, which further contributes to the simplicity of construction of the tool according to the present invention. It should further be noted that preferably the annular member 31 is arranged in a radially remote position relative to the connection means 13 with respect to the drive shaft. In this manner, it is unnecessary for the annular member to have particular capacities in terms of mechanical resistance and it can be constructed by means of an annular planar plate which is formed so as to define the recessed portions and the projecting portions.
The rotary tool 1 is therefore generally defined by means of a series of disc-like modules being placed side by side, each one being formed by a pair of disc-like elements 10 and an annular member 31, each supporting a plurality of cutting elements 2. In the present embodiment, each module has an individual pair of disc-like elements 10 but it is evident that a single disc-like element 10 could be shared between two contiguous modules.
According to the present embodiment, the cutting elements 2 associated with a pair of disc-like elements 10 are staggered angularly with respect to the cutting elements 2' which are contained between the pair of axially successive disc-like elements 10'.
In other words, the modules are staggered with respect to each other so that the cutting elements act on the material at successive times during the rotation of the tool.
With reference then to Figure 4, there is illustrated an example of the use of the rotary tool according to the present invention in a cutting machine 100.
The machine 100 comprises a charging device 4 for the introduction and optionally the collection of the material to be cut in an introduction channel 101.
Preferably, the charging device is produced by means of a plurality of rotating blades 41 which transport the material as far as an introduction plane 102, which is provided with a plurality of slots which are capable of allowing the passage of the blades 41.
When the blades 41 pass through the slots, the material transported thereby is released and set down on the introduction plane 102, from which it can continue through a plane which is inclined towards a cutting chamber 109 where the rotary tool 1 is received.
The rotary tool 1 is preferably arranged in the region of a base surface of the machine 100 so as to define a channel 105 of reduced cross-section, whose cross-section is less than that of the introduction channel 101.
The rotation of the tool 1 is orientated in a direction so as to direct the material from the introduction channel 101 towards the channel 105 of reduced cross-section, as indicated by the arrow R in the Figure.
In the region of the channel 105 of reduced cross-section, the machine 100 further comprises an abutment element 5 which substantially obstructs the channel 105 during the passage of the material and which the material to be cut which is caused to move by the rotary tool 1 abuts.
More specifically, the abutment element 5 is arranged so that the cutting portions 20 pass adjacent to the abutment element 5 during the rotation of the tool 1, substantially brushing it.
The position of the abutment element 5 with respect to the tool 1 is therefore such that the cutting portions 20 pass at the minimum possible distance from the abutment element 5 without there being any risk of interference between the abutment element and the tool during the rotation thereof. By way of example, that distance may be equal to a few millimetres but will be variable in accordance with the dimensional tolerances of the machine and the plays provided for the moving parts.
Since only a minimal spacing is provided between the abutment element 5 and the cutting portions 20, the passage of the material downstream of the abutment element 5 will be allowed only for the material transported inside the transport cavities 3.
In fact, all the material having dimensions greater than the length, width, depth or the diagonal development of the transport cavity 3, respectively, in accordance with the orientation of the material portion, cannot be received in that cavity and consequently cannot overcome the barrier defined by the abutment element 5. Vice versa, the material which has such dimensions as to be able to be contained in the transport cavity 3 and which is received therein during the rotation of the tool 1 can pass the abutment element 5. According to a preferred embodiment and also with reference to Figure 6, the abutment element 5 is constructed by means of a transverse bar which is substantially parallel with the axis of the rotary tool 1 and which faces it at a longer side thereof.
Advantageously, the abutment element 5 is fixed in an adjustable manner to a support 52 which is connected to the frame of the machine 100. According to the present embodiment, the abutment element 5 has a plurality of notches 51 in which there are received a locking screw 50 which allows the fixing in the desired position thereof, respectively. The notches extend substantially in a radial direction with respect to the tool 1 and, in that manner, the spacing may advantageously be adjusted between the abutment element 5 and the tool 1.
Furthermore, again according to a preferred embodiment, the machine 100 comprises a second abutment element 5' which has features which are similar to the first abutment element 5 and which is arranged downstream thereof.
That second abutment element 5' allows subsequent prevention of the passage of material having dimensions greater than the predetermined measurement defined by the dimension of the chambers 3, defining another barrier to the passage of material having greater dimensions.
With reference then also to Figure 5, the cutting machine 100 according to the present invention further comprises a deflection grid 6 which is arranged downstream of the abutment element 5 and the rotary tool 1.
The grid has mesh having such dimensions as to allow the passage of cut material which has dimensions smaller than a predetermined measurement.
Also with reference to Figures 6A and 6B, the grid 6 is preferably developed so as to face the rotary tool 1, and is formed by a plurality of plates 60 which are parallel with the planes defined by the disc-like elements 10. Still according to a preferred embodiment, the distance between two plates is substantially equal to the width of a single module. Furthermore, the plates 60 have a curved edge 61 which faces the rotary tool 1 and have a development which substantially corresponds to a sector of the lateral surface of the rotary tool. In that manner, there may be provision in that sector for a minimum distance between the tool and the grid, for example, equal to a few millimetres, as in the preceding case. Consequently, that feature allows further control of the dimensions of the material since the material which has dimensions greater than the mesh of the grid, defined in this case by the plates 60 themselves, will remain inside the cavities 3, while the material remaining will be discharged by means of the centrifugal action which is imparted by the rotation of the rotary tool itself towards a transition section 106. Therefore, the machine according to the present invention advantageously does not require the presence of additional discharging devices.
The material which is not discharged from the cavities 3, for example, because of excessive dimensions for passage through the mesh of the grid 6, can carry out another rotation and can again be subjected to a chopping action by means of the action of the cutting portions 20 on the abutment element 5. At the discharge from the transition section 106, there is defined a vertical conduit 108 which allows the introduction of the cut material to a collection container 8 which is constructed, for example, by means of a tank. The collection container 8 is preferably supported on arms 81 which allow the movement and the overturning thereof in order to carry out the emptying thereof.
It may be noted that the machine 100 may be constructed to be both a fixed machine and a towed machine.
In that second case, the machine further comprises a rear roller 9.
Advantageously, the actuation of the machine 100 may be carried out by means of a power take-off 110, which causes the rotary tool and the other movable components to rotate by means of a transmission system 111, which is only partially visible in the Figure.
With reference now to Figures 7, 8 and 8A, there will be illustrated a first construction variant of the machine according to the present invention.
In this case, the machine 100 also comprises a loading device 4 which is constructed by means of a plurality of rotating blades 41, which transport the material as far as the introduction plane 102, and which is provided with the holes 103 which are capable of allowing the passage of the blades 41.
At the channel 105 of reduced cross-section, the machine 100 further comprises the abutment element 5 which is capable of abutting the material to be cut which is caused to move by the rotary tool 1.
Then with reference also to Figure 8, the machine 100 according to the present construction variant further comprises a grid 6 which is arranged downstream of the abutment element 5 and the rotary tool 1.
The grid has mesh having such dimensions as to allow the passage of cut material having dimensions less than a predetermined measurement.
The grid 6 extends opposite the rotary tool 1, also with small spacing, over at least a sector of the circumference defined by the cutting elements 2.
In that manner, the material which has dimensions greater than the mesh of the grid will remain inside the cavities 3 while the material which remains will be discharged by means of gravitational force into a transition section 106.
The machine according to the present construction variant further comprises discharge means 7 for the cut material which are capable of transporting the cut material from the transition section towards a discharging section 107.
Preferably, the discharge means comprise ventilation means 7 such as a bladed fan, which are capable of producing a flow of air which allows the cut material to be urged towards the discharging section 107.
The material may be discharged from the discharging section 107 out of the machine by means of a tapering diffuser 82 which is illustrated in the embodiment of Figure 11 and which conveys the material urged by the ventilation means towards a tank or other similar container.
Alternatively, in this case, the discharging section 7 may also be arranged immediately downstream of the rotary tool 1, therefore without the use of the grid 6.
Another construction variant of the present invention is illustrated in Figure 9.
In this case, the rotary tool has a rotation axis which is substantially perpendicular to the axis of the collection device and parallel with a direction of advance A of the material inside the machine.
The tool 1' which is described in Figure 10 is constructed by means of a series of discs 1a, 1b, 1c, 1d arranged one above the other with decreasing diameter.
In a peripheral region of the discs, there are supported the cutting elements 2 which are arranged substantially parallel with the development plane of the discs 1a, 1b, 1c, 1d.
In the present construction variant, each disc 1a, 1b, 1c, 1d is associated with a respective abutment element 5a, 5b, 5c, 5d which are fixed by means of the support 52.
Then with reference to Figures 11A, 11B and 11C, there are illustrated additional construction variants of the tool 1 according to the present invention, in which the disc-like elements 10 have a serrated outer edge, a V-like notch and an increased diameter, respectively.
According to another alternative embodiment which is illustrated in Figures 12 and 12A, the cutting elements 2 are supported in a pliable manner on the disc-like elements 10. In that case, the cavities 3 are normally closed and remain defined following a tangential movement of the cutting element 2 which is generated by an impact thereof with the material to be cut.
That embodiment is found to be particularly good in the case where there are present stones and other hard material between the material to be cut.
Another construction variant is described in Figures 13 and 13A, in which the disc-like elements 10 comprise radial extensions 15.
In that case, the abutment element 5 has a plurality of notches 51 which are capable of allowing the passage of the radial extensions 15.
In that manner, in addition to the action of the cutting elements 2, there is carried out another chopping action of the material by means of the action of the radial extensions 15.
Another construction variant is described in Figures 14 and 14A, in which the cutting element 2 is developed substantially in the transverse direction with respect to a tangential direction which is defined by the disc-like elements 10.
In that case, the cutting elements 2 may be fixed to a support 16 which extends from the cavity 3.
In that embodiment, the cutting elements 2 are staggered two by two, in other words, the cutting elements 2 which are associated with a pair of disc-like elements 10 are adjacent to a cutting element which is angularly staggered along the axis X and, at the side opposite a cutting element, which is arranged in accordance with the same angular orientation. Furthermore, a single cutting element 2 preferably extends between two disc-like modules and in accordance with a preferred embodiment is fixed to two axially contiguous supports 16.
It may be noted that the same configuration is further also applicable to other embodiments described and in general to any rotor which is constructed in accordance with the present invention.
Figures 15 and 15A illustrate a solution similar to the preceding solution, in which each pair of disc-like elements 10 supports two cutting elements 2 which are staggered by 180° relative to each other.
Furthermore, the angular staggering between contiguous modules is equal to 90°.
Figures 16 and 16A illustrate a construction variant of the embodiment of Figure 1, in which the cutting elements are radially projecting in the region of the cutting portion with respect to the disc-like elements 10.
Therefore, the invention solves the problem set, at the same time achieving a plurality of advantages, including the possibility of obtaining cut material having sufficiently uniform dimensions, as a result of the fact that the material can be conveyed towards the collection zone only when it is collected in the transport cavities which can take only material which is chopped according to a given dimension. Furthermore, the material, once it has been cut, is collected in the cavities, thereby preventing additional impacts against the structure of the machine and, consequently, reducing the forces to which the mechanical components are subjected.
Subsequently, the material being discharged from the transport cavity may be discharged without requiring suitable discharge devices.
In addition, the structure having disc-like elements advantageously allows a high level of modularity of the tool, thereby becoming readily adapted to various construction requirements.

Claims

A rotary tool (1) for cutting materials comprising a plurality of disc-like elements (10) which are arranged side by side in the same axis (X), a plurality of cutting elements (2) which are contained between pairs of disc-like elements (10) opposite each other,
characterized in that respective transport cavities (3) are defined between tangentially contiguous cutting elements (2), the cavities being facing a cutting portion (20) of the cutting element (2) and being capable of receiving the cut material during at least a portion of rotation of the tool (1) about the axis (X), wherein the disc-like elements (10) are formed as a single member and are substantially flat-shaped.
A rotary tool (1) according to claim 1, comprising an annular member (31) which is arranged so as to be coaxial to the disc-like elements (10) and on which there alternate projecting portions (32) to which there are detachably fixed the cutting elements (2) and recessed portions (33) which are capable of defining the transport cavities (3).
A rotary tool (1) according to claim 1 or 2, wherein each disc-like element (10) has connection means (13) with respect to a drive shaft.
A rotary tool (1) according to claims 2 and 3, wherein the annular member (31) is arranged in a position with radial spacing with respect to the connection means (13).
A rotary tool (1) according to any one of the preceding claims, wherein the cutting portion (20) of the cutting element projects at the transport cavity (3).
A rotary tool (1) according to any one of the preceding claims, wherein the cutting elements (2) associated with a pair of disc-like elements (10) are staggered angularly along the axis (X) with respect to the cutting elements (2') which are contained between the pair of axially successive disc-like elements (10').
A rotary tool (1) according to the preceding claim, wherein the cutting elements (2) which are associated with a pair of disc-like elements (10) are adjacent to cutting elements (2') which are staggered angularly along the axis (X) and, at the opposite side, are adjacent to cutting elements (2'') which are arranged in accordance with the same angular orientation.
A rotary tool (1) according to any one of the preceding claims, wherein the disc-like elements (2) have notches in the region of the outer diameter so as to define seats for receiving the cutting elements (2).
A rotary tool (1) according to any one of the preceding claims, wherein the disc-like elements (2) are of annular form with a variable outer diameter, the extent of the diameter being such that an annular portion (11) which is opposite the cutting portion (20) of the cutting element (2) is arranged in a radially lower position with respect to the cutting portion (20) and an annular portion (12) which is opposite an end (21) which is opposite that cutting portion (20) is radially aligned with that end (21).
A rotary tool (1) according to any one of the preceding claims, wherein the cutting elements (2) are supported in a pliable manner on the disc-like elements (10), the cavity (3) being defined following a tangential movement of the cutting element (2) generated by an impact with the material to be cut.
A cutting machine (100) which comprises a rotary tool (1) according to any one of the preceding claims, an abutment element (5) which is capable of abutting the material to be cut which is caused to move by the rotary tool (1) and which is arranged in such a manner that the cutting portion (20) passes adjacent to the abutment element (5) during the rotation of the tool (1), discharging means (7) for the cut material which are capable of transporting the cut material towards a discharging section (107).
A cutting machine (100) according to claim 11, wherein the distance between the abutment element (5) and the cutting portions (20) during the rotation of the tool (1) is such that passage downstream of the abutment element (5) is allowed only for portions of material having dimensions less than a predetermined measurement, the measurement being defined by the extent of the cavity (3).
A cutting machine (100) according to claim 12, comprising a grid (6) which is arranged downstream of the abutment element (5) and the rotary tool (1) and which is capable of allowing the passage of cut material having dimensions less than a predetermined measurement.
A cutting machine (100) according to claim 13, wherein the grid (6) comprises a plurality of parallel plates (60).
A cutting machine (100) according to any one of claims 11 to 14, wherein a channel (105) of reduced cross-section is defined, the channel of reduced cross-section being obstructed by the abutment element (5), the passage of the cut material downstream of the abutment element (5) taking place inside the transport cavity (3).