Agricultural machine with hydraulic system for controlling the services of a tool-holder chassis in a simultaneous way independently from the actuation of the inter-row units

Abstract

An agricultural machine comprises a tool-holder chassis (200), at least one inter-row unit (100), and a hydraulic system (600) comprising a delivery line (301) suitable for being connected to a primary pump (P) to feed pressurized oil to a hydraulic actuator (103) of the inter-row unit and a return line (302) connected to a reservoir (303); the hydraulic system (600) comprises a divider-distributor (6) arranged in the delivery line (301) and having a primary outlet (60) connected to the hydraulic actuator (103) of the inter-row unit (100) and a plurality of secondary outlets (61) connected to the services of the tool-holder chassis (200); a distributor (4) is arranged in the primary outlet (60) of the divider-distributor (6) and has a first outlet (41) connected to the hydraulic actuator (103) of the inter-row unit and a second outlet (42) connected to the return line (302) leading to the reservoir (303); the hydraulic system (600) being configured so that the distributor (4) can be constantly crossed by pressurized oil from the divider-distributor (6).

Description

[0001] AGRICULTURAL MACHINE WITH HYDRAULIC SYSTEM FOR CONTROLLING THE SERVICES OF A TOOL-HOLDER CHASSIS IN A SIMULTANEOUS WAY INDEPENDENTLY FROM THE ACTUATION OF THE INTER-ROW UNITS

[0002] DESCRIPTION

[0003] The present invention relates to an agricultural machine with a hydraulic system for controlling the services of a tool-holder chassis in a simultaneous way and independently from the operation of inter-row units.

[0004] The agricultural machines used to do localized under-foliage work in vineyards or orchards are equipped with an inter-row unit to work the terrain between two plants, preventing the tool from damaging the stems (stumps) of the plants. Under-foliage work can be of many different types: soil work, clearing, sucker removal, fertilizing, seeding, and the like.

[0005] Fig. 1 shows an inter-row unit (100). The inter-row unit (100) comprises a working tool (101 ). The tool (101 ) is connected to a straddle lever mechanism used to retract the working tool (101 ) from its working position to go around the stump without damaging the plant. The presence of the stump of the plant is detected by a rod feeler (102) that actuates the lever mechanism, generally of hydraulic type, thus moving the tool (101 ).

[0006] Fig. 2 shows an operational sequence of the inter-row unit (100). Drawing A shows the feeler (102) that goes in contact with the stump. Drawing B illustrates an actuation of the straddle lever mechanism that causes the tool (101 ) to be retracted. Drawing C illustrates the tool (101 ) that has passed beyond the stump and returns to its initial working position.

[0007] The tools (101 ) applicable on the inter-row unit (100) can be of multiple type in order to perform various agronomic operations required by the specific needs of the crop, season or agronomic techniques used by the farmer. Generally, passive tools (blades, hoeing plough, idle discs, etc.) are applied.

[0008] Alternatively, the tools can be driven by a hydraulic motor (lawn mowers, sucker removers, motorized discs, harrows, etc.). When considered individually, an inter-row unit is not an operating system and must be integrated in another equipment, such as a tool-holder chassis or any other piece of agricultural equipment, which performs the following tasks:

[0009] - it supports one inter-row unit (in the case of single machines) or two inter-row units (in the case of double machines that simultaneously work the under-foliage on the right-hand side and on the left-hand side) in the correct position with respect to the row in terms of distance, working depth, and tool inclination;

[0010] - it houses the parts for attachment to the tractor, such as a three-point hitch for a rear or front forklift of the tractor or, alternatively, attachment systems to structural parts of the tractor (e.g., ventral applications).

[0011] Fig. 3 illustrates a tool-holder chassis (200) supported on wheels (201 ). The tool-holder chassis (200) supports two inter-row units (100) and has attachment parts (202) for attachment to a tractor.

[0012] Generally speaking, the actuation of the inter-row unit (100), of the movements of the tool-holder chassis (200) and of the tool (101 ) is of hydraulic type. The hydraulic power can be supplied directly by the tractor or it can be generated by an external unit that uses the mechanical power at the drive shaft of the tractor.

[0013] In both cases, such hydraulic power must be controlled in terms of three primary parameters (flow, pressure and temperature). The hydraulic power is controlled by a system consisting of hydraulic components that are appropriately combined to fulfill certain functional requirements.

[0014] The hydraulic systems of the prior art generally control only the straddle lever mechanism to which the tool (101 ) of the inter-row unit is connected and provide no solutions for moving the parts of the tool-holder chassis (200) and / or for operating any other non-passive working tools. Such needs are usually handled with solutions that are separate from the primary hydraulic system.

[0015] A first solution provides for adding one or more additional hydraulic pumps that are driven by the primary pump (P) in the case of a system that is independent of that of the tractor. Thus, in such a case there are two or more separate hydraulic circuits, each one being suitable for performing its own functions.

[0016] A second solution provides for adding one or more additional hydraulic lines that are directly connected to the tractor. Also in this case, disconnected circuits, which are yet under the same tractor, are created.

[0017] Both solutions are impaired by several drawbacks.

[0018] The first solution is very complicated in terms of technical systems. Many components are redundant. As a result, the hydraulic system is messy, cumbersome, heavy, and very expensive in terms of purchase, operation, and maintenance costs.

[0019] The second solution takes the performance required from the tractor to the extreme, limiting its applicability only to certain types of tractors. In fact, only the most advanced models of tractors can simultaneously supply multiple oil flows that work with different flow rates and pressures.

[0020] US4518043 describes an agricultural machine having a hydraulic system with a priority valve (122) that is capable of operating the actuator (56) of the inter-row unit, the actuators (36, 70) of the services, and a hydraulic motor (30) of a driven tool. The actuator of the inter-row unit is a double-effect actuator. A distributor (130) is arranged between the priority valve and the actuator of the inter-row unit. Such a distributor (130) provides for enabling or disabling the power supply of the actuator of the inter-row unit; if the actuator (56) is not powered, the distributor (130) does not provide for an outlet on an oil return line. In such a circumstance, the distributor (130) is completely closed and the flow on the line (124) is interrupted. Therefore, the hydraulic circuit must have two by-pass lines (1 10, 1 17) with respective valves (1 12, 108) to bypass the priority valve (122) if the distributor (130) is closed, i.e., the actuator (56) does not require any oil. As a result, the flow through the priority valve (122) is discontinuous because it occurs only in the case when both valves (1 12, 108) are closed. Such a solution is impaired by several drawbacks, such as system complexity, energy waste, fluid pulsation in the circuit, and part stress. ln addition, the reunification downstream of the distributor (130) of the flow that is originally divided by the priority valve (122) results in an operational interdependence of the components (services, driven tools, and inter-row unit). Any pressure increase due to the work of the actuators (36, 70) of the services or of the hydraulic motor (30) of the driven tool determines a reduction of the efficacy of the actuator (56) of the inter-row unit, namely a reduction in the available pressure drop and consequently in the power of the actuator of the inter-row unit.

[0021] Moreover, the entire flow rate of the pump goes through the valve block (22) leading to the actuators of the services and of the driven tool, regardless of the actual needs, possibly causing the unnecessary overheating of the hydraulic system.

[0022] Furthermore, it should be noted that the by-pass valve (108) allows to protect only the actuator (56) of the inter-row unit from overpressure. In contrast, the actuators (36, 70) of the services or the hydraulic motor (30) of the driven tool are not protected from overpressure.

[0023] The purpose of the present invention is to eliminate the drawbacks of the prior art by providing an agricultural machine equipped with a single-circuit hydraulic system capable of: controlling the straddle lever mechanisms of one or more inter-row units, controlling the services (hydraulic actuation of the moving parts) that are required for the tool-holder, powering any driven work tools (lawn mower, brush stripper, brushes, motorized discs, harrows, etc.).

[0024] Another purpose is to provide such an agricultural machine that has an ordered, lightweight, space-saving, and inexpensive hydraulic system that is easy to install, operate, and maintain.

[0025] Still another purpose is to provide such an agricultural machine having a hydraulic system with a minimum number of parts that does not require using high-performance tractors, especially in terms of hydraulics. These purposes are achieved according to the present invention with the characteristics of the attached independent claim 1 .

[0026] Advantageous embodiments of the invention will appear from the dependent claims.

[0027] Further features of the invention will appear clearer from the following detailed description, which refers to its merely illustrative and therefore nonlimiting embodiments, illustrated in the accompanying drawings, wherein:

[0028] Fig. 1 is a perspective view of an inter-row units for an agricultural machine;

[0029] Fig. 2 shows three views illustrating three operational phases of the inter-row unit of Fig. 1 , respectively;

[0030] Fig. 3 is a perspective view illustrating a tool-holder chassis supporting two inter-row units;

[0031] Fig. 4 is a block diagram schematically illustrating a hydraulic system of an agricultural machine according to the invention, in a simpler form;

[0032] Fig. 4A is a block diagram, illustrating the divider-distributor block of Fig. 4 in greater detail;

[0033] Fig. 5 a block diagram schematically illustrating the hydraulic system of an agricultural machine according to the invention, in a more complex form; and

[0034] Fig. 6 is a block diagram illustrating an anti-explosion system arranged downstream of the hydraulic system of the agricultural machine according to the invention.

[0035] With reference to Fig. 4, a hydraulic system of an agricultural machine according to the invention is described, which is comprehensively indicated with reference numeral 600.

[0036] A pump (P) generates an oil flow for the hydraulic system (600). The pump (P) can be integrated in the tractor (300) or can be an external unit. In any case, the pump (P) has a delivery line (301 ) used to send pressurized oil to the hydraulic system (600), which has a return line (302) used to discharge the oil into a reservoir (303). The hydraulic system (600) comprises the following parts arranged in series one after the other in the delivery line (301 ):

[0037] - a pressure regulator (1 ),

[0038] - a flow regulator (2),

[0039] - a divider-distributor (6),

[0040] - a valve (3), and

[0041] - a distributor (4).

[0042] The pressure regulator (1 ) has an inlet connected to the delivery line

[0043] (301 ), a first outlet connected to the flow regulator (2) and a second outlet connected to the return line (302).

[0044] The flow regulator (2) has a first outlet (21 ) connected to the return line

[0045] (302) and a second outlet (22) connected to the divider-distributor (6). The flow regulator (2) can be omitted if the flow rate of the pump (P) exactly corresponds to the operating requirements.

[0046] The valve (3) is a three-way directional valve having one inlet connected to the divider-distributor (6), a first outlet (31 ) connected to the return line (302) and a second outlet (32) connected to the distributor (4).

[0047] The function of the valve (3) is to allow the operator to manually recall the tool (101 ) by hydraulically isolating the inter-row unit (100) in order to cause the tool (101 ) to move back to its idle position due to the lack of oil. Alternatively, such a function can also be implemented with different hydraulic logics.

[0048] The distributor (4) has a first outlet (41 ) connected to a hydraulic actuator (103) that drives the lever mechanism to which the tool (101 ) of the inter-row unit is connected, and a second outlet (42) connected to the return line (302). The hydraulic actuator (103) is a single-effect hydraulic jack, that is, the hydraulic actuator (103) has a single oil inlet.

[0049] The distributor (4) is controlled by the feeler (102) of the inter-row unit. The function of the distributor (4) is to transform the mechanical movement of the feeler (102) that senses the stump into a hydraulic movement of the lever mechanism to which the tool (101 ) is connected, i.e., a rotation or displacement of the tool (101 ). The hydraulic system (600) comprises the divider-distributor (6) arranged in the delivery line (301 ) of the primary pump (P) downstream of the flow regulator (2) (if any) and upstream of the distributor (4) that powers the hydraulic actuator (103) of the tool (101 ) of the inter-row unit.

[0050] Although Fig. 4 shows the divider-distributor (6) as a single block, evidently, the divider-distributor (6) can comprise multiple components that, when put together, have the same function as the divider-distributor (6).

[0051] The divider-distributor (6) comprises:

[0052] - an inlet connected to the outlet (22) of the flow regulator (2),

[0053] - a primary outlet (60) suitable for being used to control one or two interrow units (100),

[0054] - a plurality of secondary outlets (61 ) suitable for being connected to the services of the agricultural machine,

[0055] - a return outlet (62) connected to the return line (302) of the hydraulic system.

[0056] In such a case, the services can be movable elements of the tool-holder chassis (200) or of any agricultural machine with tool-holding function.

[0057] The divider-distributor (6) comprises a divider unit (63) suitable for dividing the flow coming from the delivery line (301 ) of the primary pump into a primary line (63a) and a secondary line (63b)

[0058] The primary line (63a) is connected to the primary outlet (60) of the divider-distributor (6) and is suitable for powering the hydraulic actuator (103) of the inter-row unit (100).

[0059] The secondary line (63b) is connected to a distributor unit (66) that distributes the oil to the secondary outlets (61 ) intended for services. The distributor unit (66) is a multiple distributor, that is, a distributor that has a plurality of outlets to power a plurality of services.

[0060] The distributor unit (66) can be controlled electrically, hydraulically, or manually by means of electrical signals, hydraulic signals, or manual control actions from a user-operated interface to enable or disable the services.

[0061] The flow rate of the oil in the secondary line (63b) is generally a fixed value regardless of the variation in the flow rate in the delivery line (301 ). However, the flow rate can be varied either manually, hydraulically or electrically to adjust the response speed of the movements of the services to the user's requirements. The flow rate of the oil in the secondary line (63b) is preset during the calibration of the machine. In any case, the lines (63a, 63b) can work simultaneously at very different pressures.

[0062] With such a system, a single hydraulic system (600) is used to operate the inter-row unit (100), even during a movement of the elements of the toolholder chassis obtained by means of the oil flowing into the secondary outlets (61 ) of the divider-distributor (6).

[0063] Due to the configuration of the divider-distributor (6) and of the distributor (4), the oil flow to the distributor (4) controlled by the feeler (102) and to the services is always present. Therefore, the hydraulic system (600) is configured in such a way that the distributor (4) can constantly receive pressurized oil from the divider-distributor (6), regardless of the position of the feeler (102). This is possible because of the peculiar operation of the distributor (4). In cases where the hydraulic actuator (103) is fully extended (i.e., the feeler (102) has no interaction with the stump), the distributor (4) is configured to pour the oil into the exhaust line (302), while maintaining the hydraulic actuator (103) at a pressure suitable for the correct operation. In cases where there is a need for oil to or from the hydraulic actuator (103) (depending on the interaction of the feeler (102) with the stump), the distributor (4) is configured to direct the oil to the hydraulic actuator (103) or the exhaust line (302), respectively.

[0064] With such an architecture, a constant power supply of the hydraulic actuator (103) of the inter-row unit and of the actuators of the services is ensured, without having to provide by-pass lines to bypass the dividerdistributor (6). This results in the lack of fluid pulsations in the circuit, lower stress and longer part life, system simplification and greater energy efficiency. In addition, the two flows separated by the divider unit (63) are distinct and separate and perform their function in a completely independent way (inter-row unit power supply and service power supply). The two flows are reunited only before reentering the reservoir (303). Referring to Fig. 4A, the divider unit (63) comprises a priority valve (68). The priority valve (68) is a three-way valve having one inlet and two outlets.

[0065] The outlet (22) of the flow regulator (2) is connected to the inlet of the priority valve (68).

[0066] The priority valve (68) comprises:

[0067] - a first outlet connected to the primary line (63a) connected to the primary outlet (60) of the diverter-distributor, and

[0068] - a second outlet connected to the secondary line (63b) connected to the distributor unit (66).

[0069] The priority valve (68) divides the oil flow coming from the delivery line (301 ) of the primary pump into the two lines (63a, 63b). The priority valve (68) can be a control valve capable of varying the flow rate in the two lines (63a, 63b) according to the needs of the agricultural machine. Its distinctive feature is that it divides the flow (according to preset adjustable percentages) between lines subjected to significantly different pressures (e.g., one line in exhausting mode, and the other line at maximum pressure).

[0070] The divider unit (63) may also comprise a pressure relief valve (64) and an exhaust valve (65).

[0071] The pressure relief valve (64) is a two-way valve having an inlet connected to the secondary outlet of the priority valve (68) and an outlet (64a) connected to the exhausting outlet (62) of the divider-distributor.

[0072] The exhaust valve (65) is a three-way valve. The exhaust valve (65) has an inlet connected to the secondary outlet of the priority valve, a first outlet (65a) connected to the exhausting outlet (62) of the divider-distributor, and a second outlet connected to the secondary line (65b) that is connected to the distributor unit (66).

[0073] For safety reasons, the oil flow on the secondary line (63b) faces the pressure relief valve (64) that is set at a maximum pressure. If the pressure is higher than the maximum pressure, the pressure relief valve (64) opens towards the exhaust, thus reducing the pressure. Moreover, the oil flow on the secondary line (63b) passes into the exhaust valve (65) that is normally open towards the exhaust (62) of the dividerdistributor in such a way to have a continuous oil drain.

[0074] When the operator operates a service, the exhaust valve (65) closes the outlet (65a) and opens the outlet (65b) to the distributor unit to feed oil to the required service. In such a case, the oil is diverted to the distributor unit (66) and directed to the desired service. Such a solution reduces the oil path and thus the overheating in the hydraulic system.

[0075] Fig. 5 illustrates a more complete version of the hydraulic system (600) according to the invention that is used to control two inter-row units (100).

[0076] In such a case, the inter-row units are equipped with hydraulically driven working tools, that is, tools that require a continuous supply of oil to make the movements (e.g., rotations) that are necessary to perform their function. Such types of tools are defined as “driven tools” and can be lawn-mowers, sucker removers, motorized discs, harrows, brushes, etc.

[0077] The case of two driven tools (701 ) arranged to the left and to the right with respect to the traveling direction of the tractor is described hereinafter.

[0078] Each driven tool (701 ) must be moved by a respective hydraulic actuator (703), such as a hydraulic motor, which in turn requires a continuous oil flow.

[0079] In such a case, a flow diverter (7) of three-way type is inserted into the primary outlet (60) of the divider-distributor. The diverter (7) has:

[0080] - a first outlet (70) suitable for powering the hydraulic actuators (103) of the lever mechanism of the inter-row unit, and

[0081] - a second outlet (71 ) suitable for powering the hydraulic actuators (703) of the driven tools (701 ).

[0082] The diverter (7) is separate from the divider-distributor (6). Moreover, the diverter (7) is substantially different from a priority valve. In fact, the diverter (7) diverts the entire flow either to the inter-row units (100) or to the driven tools (701 ). In contrast, the priority valve (68) of the divider-distributor divides the flow into two parts that are directed to the services and to the diverter (7), respectively. The provision of the divider-distributor (6) and of the diverter (7) makes it possible to separate the supply lines that feed the service actuators and the supply line that powers the actuators of the driven tools, thus ensuring a total independence between the services and the driven tools.

[0083] In such a case, the agricultural machine comprises two inter-row units (100). Therefore, the hydraulic system (600) comprises a flow divider (5).

[0084] The flow divider (5) has two outlets (51 , 52) to divide the hydraulic system into two lines, each one serving one of the inter-row units, respectively. Each line of the hydraulic system will have a respective valve (3) and a respective distributor (4).

[0085] If the flow diverter (7) is provided, the first outlet (70) of the flow diverter

[0086] (7) is connected to the flow divider (5) that divides the flow to the hydraulic actuators (103) of the two inter-row units. If the flow diverter (7) is omitted, the primary outlet (60) of the divider-distributor (6) is connected to the flow divider (5).

[0087] Instead, the hydraulic actuators (703) of the driven tools are arranged in series in the second outlet (71 ) of the flow diverter. Alternatively, the hydraulic actuators (703) of the driven tools can be arranged in parallel.

[0088] In view of the above, by acting on the flow diverter (7), the operator can decide whether to send oil to the hydraulic actuators (103) of the inter-row units or to the hydraulic actuators (703) of the driven tools.

[0089] In order to switch on / off the drive tools, a drain valve (8) connected to a bypass line (81 ) is inserted in parallel into each actuator (703). If the drain valve

[0090] (8) is operated, the drain valve (8) opens, causing the oil to flow to the bypass line (81 ). In this way, if the actuators (703) are hydraulic motors, the hydraulic motor is stopped without shocks and / or cavitations. In fact, the hydraulic motors are stopped not because the flow rate is cancelled, but because the pressure between the delivery and the drain that are put in communication by the operation of the drain valve is cancelled.

[0091] The driven tools (701 ) may need a straddle movement to work between the stumps of the rows. Generally speaking, the driven tools (701 ) are installed on the inter-row units in replacement of the passive tools (101 ) on the inter-row unit.

[0092] Since the power supply of the hydraulic actuators (103) of the lever mechanism of the inter-row units (100) is interrupted by the flow diverter (7) during the operation of the driven tools (701 ), the use of a hydraulic accumulator (10) was considered.

[0093] A hydraulic accumulator (10) is a component that is capable of storing energy in the form of pressurized oil by means of an elastic deformation of a yielding internal element (partition occupied by an aeriform, e.g., nitrogen, or partition occupied by a spring). The yielding of the internal element can be controlled by means of calibration. The dynamics by which the pressurized oil is stored in the accumulator are determined by the calibration value. Specifically, the oil enters the accumulator if its pressure overcomes the calibration pressure of the accumulator. Conversely, the oil exits from the accumulator if the pressure inside the accumulator is greater than the pressure in the line.

[0094] The idea is to move the inter-row unit (100) not with a continuous oil flow from the pump (P) and metered by the distributor according to the position of the feeler, but with the amount of oil stored by the accumulator (10) during an initial charging phase. The advantage of such an architecture is that, once the system is charged, i.e., the fluid is stored at a working pressure inside the accumulator, a continuous flow of oil is not required. Such a flow can be advantageously used for other purposes, such as the operation of the tools (701 ) that can thus occur simultaneously with the straddle operation.

[0095] During the work, thanks to its resistance, the stump will raise the oil pressure inside the jack (103) to a higher value than the charging pressure, moving the jack backwards because of the displacement of the oil inside the accumulator (10). Once the obstacle is overcome, the pressure of the jack drops, recalling the oil from the accumulator at a pressure that allows the jack to open (the tool returns to its working position). Such an operation is achieved by configuring the distributor (4) in such a way to provide a direct communication between the jack (103) and the accumulator (10). The accumulator (10) is inserted in the exhaust line (302). Specifically, it is connected to the third way of a three-way diverter (9) with open transient. A pressure gauge (14) for checking the charging pressure and an adjustable unidirectional choke (1 1 ) may be arranged upstream of the accumulator.

[0096] The function of the choke (1 1 ) is to choke the line used by the oil to flow into the accumulator (10) without changing the line used by the oil to exit from the accumulator (10). The reduction of the passage section of a line (chocking) increases the difficulty encountered by the oil while flowing through the line. With the same flow rate, there is an increase in pressure.

[0097] The choke (1 1 ) is used to adjust the pressure that must be overcome for the oil to flow into the accumulator (10), without prejudice to the calibration of the accumulator. The choke (1 1 ) thus adjusts the rigidity of the jack (103), which is equivalent to the rigidity of the tool (701 ). The greater the pressure of the jack (103), the greater the thrust generated by the tool (701 ) will be. All this is done without repeating the initial charging of the system, i.e., regardless of the operation of the pump (P), and without changing the calibration of the accumulator. It is important that the control system of the inter-row unit is adjustable in such a way to adapt at best to the changing working conditions that are typical of agriculture, such as: different soil toughness, different resistance generated by different volumes of weeds or crop residues, different position of the land (uphill, downhill, transverse slopes).

[0098] The adjustment of the choke (1 1 ) can be done manually, hydraulically, or electrically.

[0099] A second adjustable choke (12) is arranged on the exhaust line (302) downstream of the diverter (9). The second choke (12) is to be understood as any component suitable for raising the pressure of the fluid in the exhaust line.

[0100] A pressure switch (13) complete with an acoustic or visual signaling device can be inserted into the drain line (302). The function of the pressure switch (13) is to signal when one or more threshold pressure values are reached. The charging of the accumulator (10) is done by acting on the diverter (9). When it is switched, the diverter (9) has an open transient, that is to say, the ways are in communication with each other. The oil is balanced and floods the interconnected elements, i.e., the accumulator (10), the jack (103), and the drain line (302).

[0101] By completing the operation of the diverter (9), the oil will remain trapped in the closed circuit that connects the jacks (103) to the accumulator (10), as well as in the accumulator depending on its pressure. If the oil pressure is higher than the set pressure of the accumulator, the oil will enter and charge the accumulator (10).

[0102] The oil pressure in the circuit can be controlled by adjusting the second choke (12) which is used to determine the charging pressure of the accumulator

[0103] (10). The more the second choke (12) is choked, the more the pressure in the drain line will rise. The second choke (12) can be adjusted manually, hydraulically or electrically.

[0104] Acoustic or visual information can be provided to the operator from the pressure switch (13). In addition, the charging pressure can be controlled by the pressure gauge (14).

[0105] The hydraulic system (600) according to the invention has the following advantages:

[0106] - the tractor only needs one oil delivery with continuous flow to power the tools of the inter-row units, the services of the tool-holder chassis and the driven tools;

[0107] - the hydraulic system is simple, ordered, and compact (an essential requirement in view of the reduced dimensions of vineyard machines);

[0108] - the hydraulic system is inexpensive and easy to operate and maintain;

[0109] - the hydraulic system is reliable and effective;

[0110] - the user interface of the hydraulic system is intuitive because all controls can be integrated in one control device with one system.

[0111] With reference to Fig. 6, a heat exchanger (800) can be provided downstream of the hydraulic system (600).

[0112] The heat exchanger (800) is sometimes necessary to dissipate the heat that is physiologically generated in any hydraulic system. The heat exchanger (800) is inserted into a return line (305) into which low-pressure oil flows towards reservoir (303). The reservoir (303) is connected to the pump that sends pressurized oil into the hydraulic system (600). The heat exchanger (800) is arranged upstream of the oil drain into the reservoir (303).

[0113] The heat exchanger (800) may be subjected to overpressure that may generate a structural failure of the heat exchanger (800).

[0114] In fact, pressure spikes may be generated on the exhaust line (302) due to a variety of reasons:

[0115] - malfunctioning of the vent of the reservoir (303),

[0116] - flow rate pulsations,

[0117] - ineffectiveness of the exhaust line (302),

[0118] - errors made while installing the lines.

[0119] A protection system (900) protects the heat exchanger (800) from such pressure spikes.

[0120] The protection system (900) comprises:

[0121] - a pressure switch arranged on the exhaust line (302) between the heat exchanger (800) and the reservoir (303), and

[0122] - a pressure limitator (902) arranged between the drain line (302) and a recovery vessel (903). The recovery vessel (903) is different and physically separate from the reservoir (303).

[0123] The pressure switch (901 ) is set with a first threshold pressure value. The pressure switch (901 ) is electrically connected to an acoustic emitter (904) that generates an acoustic signal when the pressure on the exhaust line (302) exceeds the first threshold value. This allows the operator to take action to lower the pressure on the exhaust line (302).

[0124] The pressure limitator (902) is set with a second threshold pressure value that is greater than the first threshold pressure value. When the pressure on the exhaust line (302) exceeds the second threshold value, the pressure limitator (902) opens to provide communication with the recovery vessel (903) so as to lower the pressure on the exhaust line (302).

[0125] The advantages of such a protection system (900) are: - increased operator safety in terms of the exposure to hydraulic fluid spills;

[0126] - increased environmental safety;

[0127] - longer life of the heat exchanger (800); - constructive and functional simplicity;

[0128] - operation (with the appropriate calibration) under any condition (even in the absence of electrical voltage).

Claims

CLAIMS1. Agricultural machine comprising:- a tool-holder chassis (200) suitable for being attached to a tractor (300); said tool-holder chassis (200) comprises services that include hydraulic actuators configured to move mobile elements of the tool-holder chassis;- at least one inter-row unit (100) mounted on the tool-holder chassis (200); said inter-row unit (100) comprises a tool (101 ), a hydraulic actuator (103) configured to operate the tool (101 ), and a feeler (102) configured to activate the operation of the hydraulic actuator (103) when the feeler (102) touches the stump of a plant, and- a hydraulic system (600) comprising a delivery line (301 ) suitable for being connected to a primary pump (P) to feed pressurized oil to said hydraulic actuator (103) of the inter-row unit, and a return line (302) connected to a reservoir (303), wherein said hydraulic system (600) comprises a divider-distributor (6) and a distributor unit (4) arranged in the delivery line (301 ); said divider-distributor (6) comprising:- an inlet connected to the delivery line (301 ),- a primary outlet (60) connected to said hydraulic actuator (103) of the inter-row unit (100), and- a plurality of secondary outlets (61 ) connected to said services of the tool-holder chassis (200),- a return outlet (62) connected to the return line (302) of the hydraulic system; said distributor (4) being arranged in said primary outlet (60) of the divider-distributor (6); said distributor (4) having a first outlet (41 ) connected to the hydraulic actuator (103) of the inter-row unit; said distributor (4) being configured to be actuated by said feeler (102) of the inter-row unit characterized by the fact that said distributor (4) comprises a second outlet (42) connected to the return line (302) leading to the reservoir (303); andsaid hydraulic system (600) being configured so that said distributor (4) can be constantly crossed by pressurized oil coming from said dividerdistributor (6), independently from the position of the feeler (102).

2. The agricultural machine according to claim 1 , wherein said dividerdistributor (6) comprises a divider unit (63) suitable for dividing the flow coming from the delivery line (301 ) into a primary line (63a) and a secondary line (63b); the primary line (63a) being connected to the primary outlet (60) of the dividerdistributor (6) to feed the hydraulic actuator (103) of the inter-row unit (100); the secondary line (63b) being connected to a distributor unit (66) that distributes the oil to the secondary outlets (61 ) used for the services; wherein the distributor unit (66) is a multiple distributor having a plurality of outlets to feed a plurality of services.

3. The agricultural machine according to claim 2, wherein the agricultural machine comprises a user interface operable by the user to enable or disable the services, and wherein the distributor unit (66) is electrically controllable by means of electrical signals from said user interface.

4. The agricultural machine according to claim 2, wherein the agricultural machine comprises a user interface operable by the user to enable or disable the services, and wherein the distributor unit (66) is hydraulically controllable by means of hydraulic flows from said user interface.

5. The agricultural machine according to any one of claims 2 to 4, wherein the hydraulic system is configured so that the flow rate of the oil in the secondary line (63b) is a fixed value relative to the total flow rate in the delivery line (301 ).

6. The agricultural machine according to any one of claims 2 to 4, wherein the hydraulic system is configured so that the flow rate of the oil in the secondary line (63b) can be adjusted by means of said divider unit (63).

7. The agricultural machine according to any one of claims 2 to 6, wherein the divider unit (63) comprises a priority valve (68) consisting of a three-way valve with one inlet and two outlets; wherein the delivery line (301 ) is connected to the inlet of the priority valve (68); and the priority valve (68) comprises:- a first outlet connected to the primary line (63a) connected to the primary outlet (60) of the divider-distributor, and- a second outlet connected to the secondary line (63b) connected to the distributor unit (66).

8. The agricultural machine according to claim 7, wherein the divider unit (63) comprises a pressure relief valve (64) and / or an exhaust valve (65) connected to the exhaust duct (302); wherein the pressure relief valve (64) is a two-way valve with one inlet connected to the secondary outlet of the priority valve (68) and one outlet (64a) connected to the exhaust outlet (62) of the divider-distributor; and the exhaust valve (65) is a three-way valve with one inlet connected to the secondary outlet of the priority valve, a first outlet (65a) connected to the exhaust outlet (62) of the divider-distributor and a second outlet connected to the secondary line (63b) that is connected to the distributor unit (66).

9. The agricultural machine according to any one of the preceding claims, wherein the hydraulic system (600) comprises a pressure regulator (1 ) and / or a flow regulator (2) arranged in the delivery line (301 ) upstream of said divider-distributor (6); said flow regulator (2) having a first outlet (21 ) connected to the return line and a second outlet (22) connected to the inlet of the dividerdistributor (6).

10. The agricultural machine according to any one of the preceding claims, wherein the hydraulic system (600) comprises a valve (3) disposed in said primary outlet (60) of the divider-distributor (6); said valve (3) having a first outlet (31 ) connected to the return line (302) and a second outlet (32) connected to the distributor (4) of the inter-row unit.1 1 . The agricultural machine according to any of the previous claims, comprising:- at least one driven tool (701 ) mounted on said tool-holder chassis (200), and- at least one hydraulic actuator (703) that operates said driven tool(701 ),wherein said hydraulic system (600) comprises a flow diverter (7) arranged in the primary outlet (60) of the divider-distributor; said flow diverter (7) being a separate element from the divider-distributor (6); said flow diverter (7) comprising:- an inlet connected to the primary outlet (60) of the divider-distributor,- a first outlet (70) connected to said distributor (4) of the hydraulic actuator (103) of the inter-row unit (100),- a second outlet (71 ) connected to said hydraulic actuator (703) of the driven tool.

12. The agricultural machine according to claim 1 1 , comprising two driven tools (701 ) arranged in the tool-holder chassis (200) and two hydraulic actuators (703) configured to move said driven tools, wherein said hydraulic actuators (703) are arranged in series in said second outlet (71 ) of the flow diverter (7).

13. The agricultural machine according to claim 11 or 12, wherein said hydraulic system (600) comprises an exhaust valve (8) arranged in parallel with each actuator (703) of the driven tool; said exhaust valve (8) being connected to a bypass conduit (81 ) to bypass the actuator (703) of the driven tool.

14. The agricultural machine according to any one of the preceding claims, comprising two inter-row units (100) arranged in the tool-holder chassis; wherein the hydraulic system (600) comprises a flow divider (5) arranged in said first outlet (60) of the divider-distributor (6) so as to divide the flow for feeding the two hydraulic actuators (103) of the two inter-row units.

15. The agricultural machine according to any one of the preceding claims, comprising an accumulator (10) arranged in the exhaust duct (302) and a flow diverter (9) arranged upstream of the accumulator (10).

16. The agricultural machine according to claim 15, wherein said hydraulic system (600) comprises a unidirectional choke (1 1 ) arranged upstream of the accumulator (10).

17. The agricultural machine according to claim 15 or 16, wherein said hydraulic system (600) comprises a second choke (12) arranged downstream of the accumulator (10).

18. The agricultural machine according to any one of claims 15 to 17, wherein said hydraulic system (600) comprises a pressure switch (13) connected to the exhaust conduit (302) upstream of the second choke (12).

19. The agricultural machine according to any of the previous claims, comprising:- a heat exchanger (800) arranged downstream of the hydraulic system (600) in a return line (305) wherein low-pressure oil flows towards a reservoir (303) connected to the pump that feeds the hydraulic system (600);- a protection system (900) that protects the heat exchanger (800) from pressure spikes; wherein the protection system (900) comprises:- a pressure limitator (902) arranged between the exhaust conduit (302) and a recovery vessel (903) that is different and physically separate from the reservoir (303).

20. The agricultural machine according to claim 19, wherein said protection system (900) comprises a pressure switch (901 ) arranged in the exhaust duct (302) between the heat exchanger (800) and the reservoir (303).

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