DESCRIPTION

The present invention relates to a tool-carrying group for agricultural machines, in particular for rotary harrows, and an agricultural machine comprising such a tool-carrying group.

A tool-carrying group constructed according to the prior art is shown in Figure 1. The group according to the prior art comprises a first flanged element A and a second flanged element B which are fixed to the supporting structure of a machine and which are provided with respective rolling bearings C which rotatably support a mechanical transmission shaft D for a rotational movement. A similar tool-carrying group is also described in EP2232972A1 in the name of the same Applicant.

In this context, the rolling bearings allow a reduction in the friction during the rotation of the shaft. However, it is evident that the presence of rolling bearings increases the complexity and the spatial requirement of the toolcarrying group.

This problem is particularly perceived in the agricultural sector, where it is known to use rotary machines, such as rotary harrows, in which there are present a large number of rotors, each of which comprises a shaft which is provided with blades and which is rotated in order to apply a mechanical action to the ground. It will be appreciated that, in this case, there is provided a tool-carrying group for each blade-carrying shaft and, therefore, it is necessary to have a high number of additional bearings.

A tool-carrying group in which the blade-carrying shaft is rotatably supported by means of a single rolling bearing is known from EP0398384A2. However, it is evident that the presence of a single bearing is not found to be optimum for firmly supporting the rotor during the processing of the ground.

In fact, the problem of supporting a rotor of a rotary harrow has evident difficulties as a result of the harsh operating conditions of the shaft which can be subjected to repeated and variable loading cycles over time. In particular, the blades which operate on the ground transmit to the respective blade-carrying shafts mechanical stresses which have a variable magnitude and direction depending on the rotation speed of the rotors, the advance speed of the agricultural machine and the conditions of the ground, as well as any obstacles (stones, stumps, pieces of wood and the like). Therefore, the tool-carrying groups have to be structurally rigid and particularly resistant in order to support the stresses transmitted by the respective blade-carrying shafts.

A peculiar aspect of the tool-carrying group described in EP0398384A2 is that the internal rolling track of the bearing is constructed in one piece in the blade-carrying shaft. Although this solution has the merit of reducing the number of additional components because the internal ring of the bearing is structurally integrated with the shaft, it involves a series of disadvantages.

First of all, the fact that the internal rolling track of the bearing is constructed in one piece in the blade-carrying shaft means that, in order to replace the bearing, particularly in the case of damage to the internal rolling track, it is necessary to replace the entire blade-carrying shaft with a resultant burden of costs for the repair. Furthermore, the fact that the internal rolling track of the bearing is constructed in one piece in the shaft involves the shaft having to be a special shaft and it not being possible to use a shaft of the conventional type. The conventional shafts which are commercially available do not in fact have rolling tracks for rolling elements.

Furthermore, the assembly process of the bearing on the shaft presupposes that the individual rolling elements are inserted through suitable openings which are formed between the internal and the external rolling tracks. This process is rather complicated and in any case it is difficult to apply because it is not clear how it is possible to construct a cage for this bearing. Furthermore, it is not clear how the openings are closed following the insertion of the rolling elements. Therefore, when the tool-carrying group is under an axial load, the rolling elements are capable of leaving the above- mentioned openings, compromising the capacity for axial loading of the group itself.

Furthermore, it must be observed that the tool-carrying group can be loaded in the presence of external contaminants, such as, for example, earth or dust, which are introduced into the rolling bearings, accelerating the wear and reducing the service-life thereof.

Furthermore, the introduction of dust or dirt into the bearings and the wear which results therefrom inevitably increases the power consumption during the rotation of the rotors.

Additional examples of known tool-carrying groups are described in GB1508504A or CN211210384U.

The technical problem addressed by the present invention is to provide a tool-carrying group and an agricultural machine comprising such a toolcarrying group which are structurally and functionally configured to at least partially overcome one or more of the disadvantages set out with reference to the cited prior art.

In the context of this problem, an object of the present invention is to provide a tool-carrying group which allows bearings to be replaced without having to replace the entire tool-carrying shaft.

Another object of the invention is to provide a tool-carrying group which allows the use and simple assembly of a shaft of the conventional type, particularly a shaft without rolling tracks for rolling elements.

An object of the invention is also to provide a tool-carrying group which has a greater capacity for loading and/or less structural complexity with respect to the known tool-carrying groups.

This problem is solved and these objects are achieved by the invention by means of a tool-carrying group and an agricultural machine comprising such a tool-carrying group which are constructed according to one or more of the features of the appended claims.

According to the invention this problem is solved by constructing a toolcarrying group for agricultural machines, in particular for rotary harrows, comprising two supports which are configured to be mounted axially with spacing on a supporting structure so as to rotatably support a tool-carrying shaft on the supporting structure.

It may be noted that, in this context, the term "tool-carrying shaft" is preferably intended to be understood to be a shaft which is configured to transmit a rotational movement from a rotational actuation device of the agricultural machine to one or more agricultural tools which are or can be fixed to an end of the shaft by reversible connection means. In a preferred embodiment, the end of the tool-carrying shaft is provided with seats or holes for bringing about a connection (for example, a bolted connection) to the tools.

Each of the two supports includes a flanged element which is configured to be removably secured to the supporting structure and in which an axial seat is defined.

It may be noted that, in this context, the term "flanged element" is preferably intended to be understood to be a mechanical component which is intended for non-permanent connection of other components by means of screws or bolts. In a preferred embodiment, the flanged element is provided with openings, preferably holes, for bringing about a bolted connection.

Each support further comprises a bearing ring which is received in the seat and which is configured to engage with the tool-carrying shaft, and a plurality of rolling elements which support the bearing ring in terms of rotation inside the seat.

The bearing ring advantageously retains the rolling elements in the seat thereof in such a manner that the support can be provided as a preassembled unit ready to receive a shaft of the conventional type on which the bearing ring can be fitted without any difficulty.

Preferably, each bearing ring is configured to engage with the tool-carrying shaft so as to axially secure the tool-carrying shaft, for example, by means of an interference connection between the ring and shaft. In this manner, in order to mount the shaft it is sufficient to insert it into the bearing rings. In a greatly preferred embodiment, the shaft has shoulders, against which the respective bearing rings abut so as to also ensure an axial securing between the rings and the shaft in the presence of a high axial load.

The rolling elements are interposed between a first rolling track which is constructed at the periphery of the bearing ring and a second rolling track which faces the first rolling track. It must be observed that, in at least one of the two supports, the second rolling track is constructed in one piece in the flanged element and is structurally integrated therewith so as to define with the bearing ring and the rolling elements a rolling bearing which is integrated in the flanged element.

It will be appreciated that, by forming the seat of the rolling elements directly in the flanged element, it is possible to use rolling elements which are larger, with equal spatial requirement of the support. Therefore, this solution allows an increase of the loading capacity of the support while reducing at the same time the structural complexity thereof. Furthermore, this solution allows a potential failure of the bearing to be resolved by replacing the corresponding support without any need for having to also replace the tool-carrying shaft. Another advantage of this solution is the possibility of mounting a bearing cage of the conventional type which is commercially available.

Preferably, in both supports the second rolling track is constructed in one piece in the respective flanged element and is structurally integrated therewith so as to define, with the respective bearing ring and the respective rolling elements, a rolling bearing which is integrated in the respective flanged element. In this manner, the production of the supports is greatly standardized.

In one aspect, the two supports are configured to be mounted on the supporting structure with spacing from each other along the axis of the tool-carrying shaft so as to effectively counteract the external stresses which tend to flex the shaft.

In one aspect, a first support of the supports comprises a first blind seat which is configured to receive a first end of the tool-carrying shaft, and a second support of the supports comprises a second through-seat, the through-hole of which is configured for the passage of the tool-carrying shaft.

Advantageously, the rolling elements are spheres. According to another advantageous aspect, the flanged element, the bearing ring and the spheres of the first support define a four-point contact ball bearing.

In some embodiments, the second support comprises an axial collar and a sealing element which is configured to be applied between the collar and the tool-carrying shaft. In this manner, the sealing element prevents contamination of the rolling elements and the rolling tracks. Preferably, the sealing element is a cassette seal.

In one aspect, the present invention relates to an agricultural machine comprising at least one tool-carrying group and furthermore a supporting structure to which the tool-carrying group is removably secured, and a toolcarrying shaft which is rotatably supported on the supporting structure by means of the tool-carrying group.

Preferably, the supporting structure comprises a box-shaped beam which includes a first wall and a second wall which are facing and spaced apart from each other. In this case, the first support is removably secured (for example, by means of a bolted connection of the respective flanged element) to the first wall, and the second support is removably secured (for example, by means of a bolted connection of the respective flanged element) to the second wall.

In some embodiments, the agricultural machine is a rotary harrow and the tool-carrying shaft is a blade-carrying shaft.

It may be noted that, in this context, the term "blade-carrying shaft" is intended to be understood to be a tool-carrying shaft which is or can be rotatably secured to a rotary harrow and which is provided to support a plurality of rotary harrow blades which - due to the rotation of the shaft - apply a mechanical action to the ground.

It must be observed that, advantageously, the agricultural machine comprises a plurality of tool-carrying groups and respective tool-carrying shafts.

The features and advantages of the invention will be better appreciated form the following detailed description of a preferred though non-exclusive embodiment which is illustrated by way of non-limiting example with reference to the appended drawings, in which:

- Figure 1 illustrates a tool-carrying group according to the prior art;

- Figure 2 is a front view of an agricultural machine according to an embodiment of the present invention;

- Figure 3 is a cross-section along the line III-III of a detail of Figure 2;

- Figure 4 illustrates a detail of Figure 3;

- Figure 5 illustrates a detail of Figure 4; - Figures 6 and 7 are perspective views of the detail of Figure 5;

- Figure 8 illustrates a detail of Figure 4;

- Figure 9 is a perspective view of the detail of Figure 8.

In the Figures, there is generally designated 100 an agricultural machine of the type of a rotary harrow comprising a plurality of rotors 110 which are provided with blades 103 for processing and refining the soil.

It may be noted that, in the present embodiment, the agricultural machine is represented by a rotary harrow and the tools of the agricultural machine are represented by blades but, as will be set out below, the same concepts may also be applied to other types of agricultural machines and respective tools, provided that they are generally characterized by an actuation of the rotary type.

The rotors 110 are associated with the frame of the agricultural machine 100 in the region of a supporting structure, preferably a box-shaped beam 102 which extends longitudinally along a longitudinal axis Y.

In some embodiments, the agricultural machine 100 may further comprise rotors 110 which are associated with foldable lateral portions of the frame.

Each rotor 110 is provided with a blade-carrying shaft 101 which extends through the box-shaped beam 102 and which is rotatable about a respective rotation axis X which is preferably perpendicular to the longitudinal axis Y of the box-shaped beam 102.

Advantageously, the blade-carrying shafts 101 are caused to rotate by means of transmission gears (not shown) which are contained in a protected manner in the box-shaped beam 102. The transmission gears in turn receive the rotational movement from a rotary actuation device 109 which is associated with the agricultural machine 1. In a preferred embodiment, the rotary actuation device 109 is a transmission box which is configured to receive the rotational movement from a power take-off (PTO) of an agricultural tractor.

In one aspect, along the longitudinal axis Y of the box-shaped beam 102, the rotors 110 are distributed with a pitch P which is defined as the distance between the rotation axes X of two adjacent blade-carrying shafts 101, as shown in Figure 2.

Each blade-carrying shaft 101 is rotatably associated with the box-shaped beam 102 by means of a tool-carrying group 10 comprising a first support 1 and a second support 1' which are mutually spaced apart and arranged coaxially relative to the rotation axis X of the respective blade-carrying shaft 101.

In a greatly preferred embodiment, the blade-carrying shaft 101 extends longitudinally between a first wall 106 and a second wall 107 of the boxshaped beam 102 which face and are spaced apart from each other. In this example, the first support 1 and the second support 1' are or can be removably secured to the box-shaped beam 102 in the region of the inlet and outlet sections of the blade-carrying shaft 101 via the same box-shaped beam. In particular, the first support 1 is removably secured to the first wall 106 and the second support 1' is removably secured to the second wall 107. This arrangement allows the first support 1 to be positioned at a distance D from the second support 1', as shown in Figure 4, so as to reduce the vibrations and the loading on the supports 1 and 1' when the shaft 101 is rotating. In one aspect, each blade-carrying shaft 101 along the individual axis X has a first end 104 which is secured to the first support 1, a longitudinal portion 103 which is secured to the second support 2 and a second end 105 which is directed at the opposite side to the first end 104 and which is provided to support tools, such as, for example, the blades 103 of the harrow. In a preferred embodiment, the longitudinal portion 103 of the shaft is defined between the first end 104 and the second end 105 in a position axially spaced apart from the first end 104 and preferably behind the second end 105 so as to ensure an adequate distance D between the rotatable securing locations of the shaft 101 along the rotation axis X.

Each of the supports 1 and 1' comprises a flanged element which is designated 2 and 2', respectively, and which is or can be removably secured to a wall of the box-shaped beam 102.

As shown in Figures 6 and 7, the flanged element 2 of the first support 1 may have, for example, a circular shape. However, the flanged element 2' of the second support 1' may have, for example, a square shape, as shown in Figure 9. It will be understood that the flanged elements 2 and 2' may have any other shape.

Preferably, each of the flanged elements 2 and 2' has openings 9 in order to construct a bolted connection with the supporting structure of the machine 1. In some embodiments, the openings 9 are holes. Preferably, the holes are through-holes and/or extend parallel with the axis X. In a greatly preferred embodiment, the holes are distributed along the perimeter of the flanged elements 2, 2'. Advantageously, the holes are configured to receive removable connection means (for example, bolts 111) with respect to the walls of the box-shaped beam 102.

There are defined in the flanged elements of the first support 1 and the second support 1' a first seat 11 and a second seat 11' which extend along the axis X, respectively. Advantageously, the first seat 11 which is defined in the flanged element 2 of the first support 1 is blind and is configured to receive the first end 104 of the blade-carrying shaft 101 at the side of the first support 1 which is directed towards the box-shaped beam 102, as shown in Figures 4 to 7. According to another advantageous aspect, the second seat 11' which is defined in the flanged element 2' of the second support 1' is passed through by a through-hole 8 and is configured to allow the passage of the longitudinal portion 103 of the blade-carrying shaft 101 through the through-hole 8, as shown in Figures 4, 8 and 9.

The first support 1 and the second support 1' each comprise a bearing ring 3 which is received in the first seat 11 and in the second seat 11', respectively, and which is configured to engage in the blade-carrying shaft 101. In order to support the bearing ring 3 in terms of rotation inside the respective seat, there is provided a plurality of rolling elements 4 which are interposed between the bearing ring 3 and the flanged element of the respective support. In particular, the rolling elements 4 are interposed between a first rolling track 5 which is constructed at the periphery of the bearing ring 3 and a second rolling track 6 which faces the first rolling track 5 and which is constructed in one piece in the flanged element of the respective support.

It must be observed that the second rolling track 6 is structurally integrated with the respective flanged element so as to define therewith, and furthermore with the bearing ring 3 and the rolling elements 4, a rolling bearing which is integrated in the same flanged element. This solution allows the use of rolling elements 4 with greater dimensions than those used in a conventional tool-carrying group as described above with reference to the prior art without this further involving a greater spatial requirement of the group itself.

Advantageously, the rolling elements 4 are spheres. According to another advantageous aspect, the flanged element 2, the bearing ring 3 and the spheres 4 of the first support 1 define a four-point contact ball bearing.

It may be noted that, in this context, the term "four-point contact ball bearing" is intended to be understood to be an angular radial bearing with a ring of spheres 4 with tracks which are configured to support axial loads in both directions. It must be observed that, for a given axial load, this bearing can also support a radial load. Therefore, a single bearing with four contact points is an advantageous alternative to two paired angular bearings with a ring of spheres, as it reduces the dimensions of the first support 1.

In some embodiments, the bearing ring 3 can be disassembled into two halves. Therefore, the flanged element 2 of the first support 1 with the spheres 4 and relevant cage 41 can be mounted independently of the two halves of the bearing ring 3.

Preferably, the flanged elements 2, 2' of the supports 1, 1' and/or the rings 3 and/or the rolling elements 4 are made from steel or another metal material having mechanical properties which are adequate for ensuring secure and durable operation of the tool-carrying group 1. In a greatly preferred embodiment, the first support 1 comprises a metal disk 112 which is associated with the flanged element 2 at the side directed towards the second support 1' and which is configured to retain the rolling elements 4 of the first support 1 in the event of a breakage thereof.

In one aspect, the flanged element 2' of the second support 1' comprises a collar 113 which extends along the axis X from the second seat 11' of the bearing ring towards the second end 105 of the shaft. Advantageously, a sealing element 7 is applied between the collar 113 and the shaft. It must be observed that the sealing element 7 is arranged along the axis X between the rolling elements 4 of the second support 1' and the second end 105 of the blade-carrying shaft 101 so as to shield the rolling elements and the relevant rolling tracks against the introduction of dirt (mud, water, dust, etc.) when the blades 103 are operational in the ground.

As shown in Figure 8, the sealing element 7 may be of the type of a cassette seal comprising a plurality of sealing lips 70 which are interposed between an external sealing ring 71 and an internal sealing ring 72. The external sealing ring 71 is received in an annular seat 73 of the collar 113 while the internal sealing ring 72 engages in a sealing manner on the bladecarrying shaft 101.

Preferably, the rings 71, 72 are rigid sealing elements, between which there are interposed the sealing lips 70 which are made from resilient material, such as, for example, an elastomer material. Preferably, the cassette seal further comprises a toroidal spring 74.

The sealing lips 70 inside the cassette seal form a greased serpentine arrangement. Filling with grease reduces the wear, thereby extending the maintenance intervals.

The invention thereby solves the problem set out while achieving a number of advantages, including:

- increasing the loading capacity of the tool-carrying group, - limiting the introduction of water, mud and dust,

- improving the lubrication,

- increasing the reliability,

- minimizing the weight and the dimensions,

- reducing the production, logistics and storage costs, - allowing interchangeability with the tool-carrying group of the pre-existing machines.