Patent Description:
There is perceived the need to connect different agricultural machines by means of an electronic control system. Typically, this control system is carried out according to an Isobus protocol. This protocol is standardized in order to control the communication between tractors, software and equipment items in order to allow an exchange of data and information items with a universal language by means of a single control console which is integrated in the cabin of the tractor.

In particular, the present invention relates to the field of agricultural machines which are provided or intended to be provided for an Isobus connection and which are actuated by the power take-off of an agricultural tractor by suitable shafts and gearboxes.

In such machines, there is perceived the problem of allowing the detection of parameters correlated with the torque and the power transmitted by the power take-off of the tractor to the driven members of the agricultural machine.

For example, the document <CIT> describes a bevel gear with angled transmission for actuating agricultural machines with a movement input shaft, a movement output shaft and a device for measuring the coordinated couple at the input shaft or the output shaft. There is particularly provision for a casing which is provided with flanged support members for a conical toothed wheel, in which there is integrated the device for measuring the couple which is provided as a device operating without any contacts and which is mounted between two bearings which are provided in the support member for mounting one of the shafts.

Additional examples of devices for detecting a mechanical stress are described in <CIT>, <CIT>, <CIT> or <CIT>.

In this context, the invention can better be used in the field of agricultural machines with foldable frames, wherein at least one lateral frame is hinged to a central frame and can generally be moved by means of fluid-dynamic actuators between an operating position (or working position) and a transport position, in which the agricultural machine takes up maximum and minimum dimensions, respectively.

In such machines, there is perceived inter alia the technical problem of jamming of the transmission shafts between the central gearbox and the transmission boxes on each lateral frame, which may cause damage to and breakage of the universal movement transmission joints as a result of the manoeuvring operations between the above-mentioned positions.

The technical problem addressed by the present invention is to provide a machine and a method 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.

This problem is solved by the invention by means of a machine and a method comprising one or more of the features of the appended claims.

According to the invention, this problem is solved by measuring by means of a torque meter the counter-torque applied between the gearbox and the central frame of the operating machine while the tractor operates the machine itself by means of the power take-off (PTO).

This measure is preferably carried out by means of one or more load cell(s) which is/are interposed between the gearbox and the frame.

Both load cells of the electronic type and cells of the hydraulic and/or electrohydraulic type are suitable for this purpose. In preferred embodiments, the cell is of the shear beam or button type.

With a particular assembly with a bracket hinged both to the frame of the machine and to the gearbox, it is possible for the torque meter which acts as a hinge pin of the bracket to be isostatic at least in the measuring state.

Advantageously, the torque meter is arranged so as to measure the counter-torque between the gearbox and the frame which supports it with reference to a movement input axis in the gearbox or a movement output axis from the gearbox.

In an embodiment, the torque meter comprises an upper plate and a lower plate, of which one is secured to the gearbox and the other is secured to the frame, the upper plate and the lower plate being secured to each other with hinge type constraints in accordance with two axes which are mutually parallel and substantially parallel with the movement input axis or the movement output axis, one of the hinge type constraints including the load cell.

It may be noted that, advantageously, the axes of the hinge type constraints are spaced apart from each other in such a manner that the hinge type constraints can act counter to the rotation of the plates about the axes.

According to another advantageous aspect, the axes of the hinge type constraints are substantially parallel with the positioning plane of the plates or the positioning plane of at least one of the plates.

Preferably, the plates are secured to each other with hinge type constraints in accordance with only two axes which are mutually parallel. Even more preferably, only one of the hinge type constraints includes the load cell.

In a construction variant of the invention, there is provision for the other of the hinge type constraints to be positioned with respect to the corresponding movement input or output axis so as to minimize the torque generated with respect to the corresponding movement input or output axis by a thrust directed along this movement input or output axis. In this manner, the disruption signal introduced into the torque measurement by the axial thrusts of the universal joints is minimized.

If the other of the hinge type constraints is arranged to identify a hinge axis which substantially intersects orthogonally with the corresponding movement input or output axis, the above-mentioned disruption signal is cancelled by the effect of the cancellation of the arm between the axial thrust of the universal joints and the hinge axis.

In one aspect, the present invention relates to a kit for a folding harrow comprising an upper plate and a lower plate which are juxtaposed, spaced apart and secured with respect to each other with hinge type constraints in accordance with two mutually parallel axes, the axes being configured to be arranged parallel with a movement input axis into a gearbox of the folding harrow or a movement output axis out of the gearbox, one of the hinge type constraints including a load cell, the kit being arranged to be interposed between the gearbox and a support frame thereof in place of a horizontal alignment spacer of lateral shafts with a universal joint of the folding harrow.

It may be noted that, in this context, the term "frame" refers to a frame which is suitable for connecting at least one agricultural implement.

The kit further includes a communication connection by means of a communication protocol which is preferably an Isobus protocol.

In some embodiments, the kit is provided to be mounted in accordance with a levelling shim of the gearbox on the relevant frame.

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

In the <FIG> generally indicates a rotary harrow with a foldable frame. The invention is further used in harrows with fixed frames or more generally in agricultural machines including a frame and a gearbox which is supported on the frame in order to be actuated by means of the PTO of an agricultural tractor generally via a transmission shaft with a double universal joint. Such machines may, for example, include milling cutters or the like.

In a preferred embodiment thereof, the harrow <NUM> comprises a frame or central frame <NUM> which carries flanges <NUM> which are capable of configuring a three-point attachment for a hydraulic lift of an agricultural tractor and two lateral frames <NUM>, <NUM> which are articulated to the central frame about respective hinges <NUM> and which can be pivoted between an operative position (illustrated in <FIG>), in which the lateral frames are lowered with a substantially coplanar arrangement, and a transport position, in which they are raised with an arrangement which is preferably mutually parallel with a minimal transverse spatial requirement of the machine <NUM>.

A plurality of rotors with relevant implements <NUM> is mounted on each of the lateral frames <NUM> and <NUM>.

In preferred embodiments, those rotors are motorized by means of respective secondary gearboxes <NUM> which are provided with movement output axes <NUM>. The secondary gearboxes <NUM> in turn draw movement from a primary or central gearbox <NUM> which is mounted on a support <NUM> of the central frame <NUM>.

The connection between the gearboxes <NUM>, <NUM> and between the central gearbox <NUM> and the power take-off of an agricultural tractor is preferably brought about by means of universal joint shafts <NUM>.

According to another aspect, for moving the lateral frames <NUM>, <NUM> there may be provided fluid-dynamic cylinders <NUM> between the central frame <NUM> and the respective lateral frames <NUM>, <NUM>.

There is interposed between the central gearbox <NUM> and the central frame <NUM> a torque meter <NUM> according to the invention, as shown in <FIG>. In some embodiments, this torque meter <NUM> comprises a pair of upper and lower plates 13a, 13b, respectively, of which one is secured to the gearbox <NUM> and the other is secured to the frame <NUM>. As better illustrated in <FIG>, the two plates 13a, 13b are preferably secured to each other with hinge type constraints <NUM>, <NUM>.

Preferably, along one side, the two plates 13a, 13b are hinged by means of a hinge pin <NUM> which extends through holes which are provided in pairs of flanges <NUM>. The plates 13a, 13b can advantageously be connected to each other at the side opposite the pin <NUM> by means of a load cell <NUM> with a pin which extends into respective coaxial holes of second flanges <NUM> and which blocks the raising of the plates 13a, 13b.

By way of example, the shear beam cells are used to measure the loads applied to pulleys, hoists, cranes and weighing installations which may be integrated in overhead cranes.

The axes X and Y of the pins <NUM> and <NUM>, respectively, are parallel and spaced apart (cf. , for example, the spacing D in <FIG>) so that the torque meter <NUM> carries out an isostatic system when viewed from a plane which is transverse to the axes X, Y mentioned above. Preferably, the axes X and Y are further parallel with the movement input axis <NUM> into the central gearbox <NUM> so that the counter-torque generated by the power which is supplied via the gearbox <NUM> and which is discharged to the central frame <NUM> passes through the load cell <NUM>.

In preferred embodiments, this load cell is provided with extensometers (not illustrated) and is therefore capable of measuring the shearing force which extends through it. With this force being known and knowing the geometry of the plates 13a, 13b and the pins <NUM>, <NUM>, therefore, it is readily possible to calculate the torque and the power supplied via the central gearbox <NUM>.

In an embodiment, the axes X and Y can be parallel with at least one of the movement output axes <NUM> from the central gearbox <NUM>. In this manner, the torque meter <NUM> can measure the counter-torque between the gearbox <NUM> and the frame <NUM> which supports it with reference to a movement output axis <NUM> from the central gearbox <NUM>.

In <FIG>, the upper plate 13a and lower plate 13b are secured to each other with hinge type constraints <NUM>, <NUM> in accordance with two axes X, Y which are mutually parallel but which are arranged in such a manner that one of the hinge type constraints includes the load cell <NUM> and the other of the hinge type constraints is positioned with respect to the corresponding movement output axis <NUM> so as to minimize the torque generated with respect to the corresponding movement output axis by a force directed in accordance with this axis. Reference has been made to the movement output axis but the result can be achieved similarly with reference to the movement input axis <NUM>, where the torque to be analysed is this one.

Preferably, the other of the hinge type constraints <NUM> is arranged to identify a hinge axis X which substantially intersects orthogonally with the corresponding movement input or output axis.

Preferably, the torque meter <NUM> is constructed with such a geometry as to be interchangeable (and therefore, to be able to replace without other adaptations), a spacer <NUM> (shown in <FIG>) which is normally used in conventional foldable harrows in order to space the assembly of the central gearbox <NUM> on the support <NUM> of the central frame <NUM> in order to level and align the movement output axes <NUM> from the central gearbox <NUM> with the movement input axes <NUM> of the secondary gearboxes <NUM>, or to level the universal joint shafts <NUM> which connect them.

It may be observed that the torque meter <NUM> of this invention can be constructed in the form of a kit suitable for both the initial equipping of an agricultural machine <NUM> and potential retrofitting of conventional machines which are normally provided with the spacer <NUM> for levelling the gearbox <NUM>. In this case, it is simply necessary to replace the spacer <NUM> with the above-mentioned kit.

According to an optional feature of the invention, the torque meter <NUM> comprises means <NUM> for reversible fixing to the gearbox <NUM>, at one side, and to the frame <NUM>, at the other. Preferably, the fixing means <NUM> are configured to cooperate with respective fixing counter-means which are provided on the gearbox <NUM> and on the frame <NUM>.

In a preferred embodiment, the fixing means <NUM> are defined in the plates 13a, 13b. In this embodiment, the upper plate 13a and lower plate 13b comprise means for reversible fixing to the gearbox <NUM> and the frame <NUM>, respectively, or vice versa.

Advantageously, the fixing means <NUM> include fixing openings or holes which are defined in the plates 13a, 13b. It may be noted that, preferably, the fixing holes are different from the mutual hinging holes of the plates themselves.

According to another advantageous aspect, the fixing counter-means also include fixing openings or holes which are defined in the gearbox <NUM> and in the frame <NUM> in positions corresponding to those of the fixing openings or holes of the plates 13a, 13b.

For example, one or more fixing holes can be provided through each of the plates 13a, 13b. The fixing holes may be through-holes or may be blind holes. In a preferred embodiment, the fixing holes are suitable for receiving bolts or other connection means, preferably of the threaded type, in order to reversibly fix the plates 13a, 13b to the gearbox <NUM> at one side and to the frame <NUM> at the other side, respectively, or vice versa.

In some embodiments, the holes for fixing to the frame <NUM> or the gearbox <NUM> in the plates 13a, 13b are constructed according to the same masks of the fixing holes of a conventional levelling spacer <NUM> and the overall thickness is identical so that the replacement can also be carried out by a non-skilled operator. In one aspect, the torque meter <NUM> is inserted in the machine <NUM> by securing the upper plate 13a to the central gearbox <NUM> and by securing the lower plate 13b to the support <NUM> of the central frame <NUM>. Preferably, the torque meter <NUM> is inserted into the machine <NUM> in a manner parallel with the direction of the movement input axis <NUM> in the central gearbox <NUM>.

The kit can be assembled in line and does not require any calibration, the torque measurement being brought about simply by the geometric parameters thereof. With this technical solution, it is possible to continuously measure the torque transmitted which in turn allows the measured data to be stored in a mass memory <NUM> in order to generate a historical archive which can be interrogated. It is thereby possible to cause data from other sensors which are fitted to the machine <NUM> to converge in the memory <NUM>, for example, temperature sensors of the gearbox <NUM>, <NUM>, the function of which is to provide historical data of the operating temperature of each gearbox/branch and to generate alarms in the event of a predetermined thermal threshold being exceeded. There are further provided three rotation sensors, one for each universal joint shaft <NUM>, which will control the possible intervention of the torque limiters in the event of occurrences of over-consumption.

In the rear portion of the harrow <NUM>, there is preferably provided at least one roller <NUM>, the position of which can be adjusted by means of hydraulic actuators <NUM> in order to vary the working depth of the implements <NUM>. Advantageously, the hydraulic actuators <NUM> are configured to be blocked by means of blocking valves <NUM>. Each roller is preferably provided with a position transducer (not shown) which detects the course of the adjustment hydraulic actuators <NUM> and consequently detects the working depth of the implements <NUM>. Two additional proximity sensors <NUM> (of which one is indicated in <FIG>) can be provided between the central gearbox <NUM> and the universal joint shafts <NUM> which connect the movement outputs thereof to the secondary gearboxes <NUM>. These proximity sensors <NUM> are used to read the angular position of the lateral universal joint shafts <NUM> during the closure step of the machine <NUM>, preventing any breakages as a result of jams thereof.

In an aspect, the historical archive of the mass memory <NUM> can be interrogated by means of an Isobus terminal or monitor <NUM> which is part of the command console integrated in the cabin of the tractor or forming part of the above-mentioned kit. Preferably, the kit includes a communication connection <NUM> by means of a communication protocol (for example, Isobus). The Isobus terminal <NUM> allows integrated control of the information items which are stored in the mass memory <NUM>, using an Isobus protocol, that is to say, using a universal language which allows communication between tractors, software and equipment items. Advantageously, the measurements stored in the mass memory can be used to monitor the degree of use of the machine. For example, it is possible to display on the Isobus monitor <NUM> information items, such as the consumption of power, the working depth, or different alarms. It is possible with the storage and integrated control of the information items also to control the maintenance activities of the harrow <NUM>, and in particular the possible extension of a warranty because the data relating to malfunctions and overloads which are not adequately controlled by the operator will be detected and stored.

Claim 1:
An agricultural machine (<NUM>) including a frame (<NUM>) which is configured to connect an agricultural implement and a gearbox (<NUM>) which is supported in the frame (<NUM>) and having at least one movement input axis (<NUM>) and at least one movement output axis (<NUM>), characterized in that there is interposed between the gearbox (<NUM>) and the frame (<NUM>) a torque meter (<NUM>) which is arranged so as to measure the counter-torque between the gearbox (<NUM>) and the frame (<NUM>) which supports it with reference to the movement input axis (<NUM>) or the movement output axis (<NUM>) at least in a working condition of the agricultural machine (<NUM>).