Handling machine comprising a hydraulic cylinder and corresponding control method

Abstract

The invention relates to a load or person handling machine comprising a handling system that includes a component actuated by means of a hydraulic actuating cylinder (8). The machine includes a hydraulic oil circulation cylinder (130) and an electric motor (110) having an output shaft (111) coupled to the rod of the hydraulic oil circulation cylinder by a mechanical linkage system (120) to slide the rod (1321) of the piston (132) of the hydraulic oil circulation cylinder, in order to supply oil via a hydraulic circuit (140) to the hydraulic actuating cylinder of said component of the handling system. The invention also relates to a corresponding control method. Figure for the abstract: Fig. 2A

Description

Title of the invention: Handling machine comprising a hydraulic cylinder and corresponding control method. FIELD OF THE INVENTION

[0001] The present invention relates generally to a handling machine comprising a hydraulic cylinder. FRONT ART

[0002] Prior art is known for handling machines comprising a handling system, such as a lifting arm with an apron equipped with a tool, and an actuation system for the handling system comprising one or more hydraulic actuating cylinders. The lifting arm of a tilting arm machine, for example, can be pivoted between a lowered and a raised position by means of a lifting cylinder, and the entire apron and tool assembly can be tilted relative to the arm by actuating a tilting cylinder.

[0003] Typically, a cylinder in the actuation system is controlled by a hydraulic circuit that includes a pump for pressurizing the oil in the hydraulic circuit to circulate it. The hydraulic circuit includes a supply line whose opening is controlled by a solenoid valve to direct the pressurized oil to the actuation cylinder in order to supply and thus actuate the actuation cylinder to move a component of the associated handling system.

[0004] However, the hydraulic pump is a noisy component. The noise of the hydraulic pump is even more noticeable when the handling machine includes an electric motor, since electric motors are relatively quiet compared to internal combustion engines such as diesel or gasoline engines.

[0005] The present invention aims to provide a new machine and corresponding control method to overcome all or part of the problems described above. Summary of the invention

[0006] To this end, the invention relates to a machine for handling loads or people comprising: - a chassis and, carried by the chassis, a load or person handling system comprising a component, such as a lifting arm, mounted movable relative to the chassis and actuable by means of an actuation system which includes at least one hydraulic actuation cylinder, such as a lifting cylinder; - a hydraulic circuit including a system for circulating oil in the hydraulic circuit to supply oil to the hydraulic actuating cylinder; characterized in that the oil circulation system comprises: - a hydraulic cylinder, called an oil circulation cylinder, comprising a hollow body, called a cylinder, and a piston, the piston having a rod and a head integral with the rod and movable within the cylinder; - an electric motor having a driveable output shaft; - a mechanical linkage system configured to transmit the motion of the output shaft of the electric motor to the piston rod of the oil circulation cylinder, so that the rotation of the output shaft of the electric motor causes the sliding movement of the rod and therefore of the piston head relative to the cylinder to circulate the oil in the hydraulic circuit in order to supply said at least one hydraulic cylinder for actuation of the handling system.

[0007] Compared to the prior art where the oil supply to a hydraulic cylinder actuating the handling system is controlled by a hydraulic pump, having a hydraulic cylinder (the so-called oil circulation cylinder) instead of a pump, along with a mechanical linkage system to directly transmit the movement from the electric motor to the rod of the hydraulic oil circulation cylinder, avoids a noisy, bulky, and energy-intensive system that would also heat the oil more, as would be the case with a hydraulic pump. The energy required to cool the oil is thus reduced.

[0008] The electric motor is used to move the rod of the hydraulic oil circulation cylinder, which thus forms part of the machine's oil circulation system. The movement of the oil circulation cylinder piston by the electric motor via the mechanical linkage allows for the supply and therefore the control of one or more hydraulic cylinders of the handling system's actuation system, i.e., another or other hydraulic components of the machine connected to one or more components of the handling system.

[0009] Such a design using an electric motor assembly mechanically connected to the rod of a hydraulic cylinder, also allows the electric motor to be used more easily at high operating speeds compared with an architecture using a pump.

[0010] The machine may also include one or more of the following features taken in any technically permissible combination.

[0011] According to a preferred embodiment, the actuating and / or oil circulation cylinder(s) is a double-acting cylinder. According to a less An advantageous solution is to replace the double-acting cylinder with two single-acting cylinders. In one particular embodiment, the cylinder is a double-acting cylinder with two rod sections extending on either side of the piston head.

[0012] According to one embodiment, the mechanical linkage system comprises an actuating lever which has: - a first part connected to the output shaft of the electric motor by a linkage system, such as a nut having a thread cooperating with a thread of the output shaft of the electric motor, the lever being mounted articulated to the linkage system around an axis orthogonal to the axis of the output shaft and to the axis of the lever (in other words articulated to the linkage system, such as the nut, around an axis orthogonal to the plane passing through the axis of the output shaft of the electric motor and the axis of the rod of the cylinder); - a second articulated part (pivot joint) to the machine chassis; - and a third part, located between the first and second parts of the lever, which is connected to the rod of the hydraulic cylinder.

[0013] The different parts of the lever are fixed to each other, preferably formed from a single piece. In other words, there is no relative mobility between said parts.

[0014] According to a particular aspect, the output shaft of the electric motor being formed by a threaded rod (or screw), the rotation of the output shaft causes the lever connected to this rotating shaft to move via a nut whose threads engage with the threads of the output shaft. The nut is coupled to the lever with a pivoting mobility of the lever relative to the nut. Thus, the lever can move forward or backward along the rotating shaft according to the direction of rotation of the motor, and this occurs simultaneously with the lever pivoting around its axis of connection to the chassis, which causes the piston rod, which is connected to the lever, to slide relative to the cylinder.

[0015] Such a design of the mechanical linkage system with such an arrangement of the lever whose linkage area with the rod of the cylinder is located between the articulation of the lever to the chassis (pivot point of the lever), and the linkage of the lever to the output shaft (point of force applied on the lever), makes it possible to benefit from a significant lever arm.

[0016] In other words, when the lever is moved by the electric motor, the lever's design provides a lever arm that allows for significant force to be applied to the rod of the hydraulic circulation control cylinder. This eliminates the need to oversize the electric motor, thus reducing its size and cost. The oil contained in the cylinder then supplies the machine's hydraulic circuit, to which one or more hydraulic cylinders of the handling system's actuation system are connected.

[0017] According to one embodiment, the third part of the lever, located between the first and the second part of the lever, is mounted articulated (pivot joint) to the rod of the hydraulic cylinder.

[0018] According to one embodiment, the hydraulic circuit includes a hydraulic distributor which includes several solenoid valves, at least one, preferably each, solenoid valve being connected on the one hand to a line, called the pressure line, connected to the oil circulation system, and to a line of an oil reservoir, and on the other hand to a line of a first chamber of said at least one hydraulic actuating cylinder and to a line of a second chamber of said at least one hydraulic actuating cylinder.

[0019] According to one embodiment, the actuation system comprising several hydraulic actuation cylinders, the hydraulic circuit includes a hydraulic distributor which includes several solenoid valves, each solenoid valve being connected on the one hand to a line, called the pressure line, connected to the oil circulation system, and to a line from an oil reservoir, and on the other hand to a line from a first chamber of one of the hydraulic actuation cylinders and to a line from a second chamber of said hydraulic actuation cylinder.

[0020] According to one embodiment, the oil circulation system includes a solenoid valve, which comprises: - a first channel connected to a first chamber of the oil circulation cylinder, - a second channel connected to a second chamber of the oil circulation cylinder; - a third line connected to an oil reservoir in the hydraulic circuit, - a fourth line connected (by a line called a pressure line) to a hydraulic distributor of the hydraulic circuit, the solenoid valve being configured to selectively present: a first supply configuration, in which the first and fourth ways are connected so that the oil present in the first chamber of the cylinder is able to pass from the first way to the fourth way to supply oil to the pressure line of the hydraulic circuit, and the third and second ways are connected so that oil from the reservoir is able to be drawn (from the third way to the second way) into the second chamber of the oil circulation cylinder; a second supply configuration, in which the second and fourth ports are connected so that the oil present in the second chamber of the cylinder is able to pass from the second port to the fourth port to supply oil to the pressure line of the hydraulic circuit, and the third and first ports are connected so that oil from the reservoir is suitable for being drawn (from the third way to the first way) into the first chamber of the oil circulation cylinder.

[0021] According to one embodiment, for the oil circulation cylinder or cylinders, the rod has a first part which extends from one side of the piston head and a second part which extends from the other side of the piston head.

[0022] According to one embodiment, the oil circulation system comprises an additional set of electric motor and hydraulic circulation cylinder, coupled together by a mechanical linkage system, and a solenoid valve which is connected on one side to the pressure line and the reservoir line, and on the other side to the hydraulic oil circulation cylinder of said additional set.

[0023] According to one embodiment, the hydraulic circuit being without a distributor, the oil circulation system comprises several oil circulation assemblies, each comprising a hydraulic oil circulation cylinder, an electric motor and a mechanical linkage system, and the actuation system comprising several hydraulic actuating cylinders, each hydraulic actuating cylinder being associated with one of said oil circulation assemblies, the hydraulic circuit comprising, for each of said hydraulic actuating cylinders, a hydraulic linkage which includes: - a hydraulic line connecting a chamber of the hydraulic actuating cylinder to a corresponding chamber of the oil circulation cylinder, and - a hydraulic line connecting the other chamber of the hydraulic actuation cylinder to the other chamber of the corresponding oil circulation cylinder.

[0024] A direct hydraulic supply circuit can thus be provided between the hydraulic cylinder for oil circulation, which is mechanically connected to the electric motor, and the hydraulic cylinder of the corresponding actuation system of the handling system.

[0025] The distributor can then be dispensed with by using several of these assemblies, each consisting of an electric motor and a hydraulic cylinder for oil circulation that is mechanically connected to the electric motor. Each component of the assembly can be small, with the oil circulation cylinder directly linked to one of the machine's hydraulic cylinders.

[0026] Regardless of the embodiment, by multiplying the assemblies on the machine, i.e., by using several small assemblies of electric motor and associated oil circulation cylinder, instead of a single large assembly, one can then benefit from all or part of the following advantages. The actuation of several cylinders of the system The handling system does not require stopping the movement because the units can be controlled in a relay fashion, with or without overlapping operating phases. Electrical consumption can be optimized according to the required movement speed by combining the activation of one or more units. If necessary, a simple distributor can be used to manage the accumulation or separation of flow rates and direct them to the actuating cylinders. It is understood that the oil flow in the hydraulic circuit can be regulated by controlling the speed of the electric motor(s).

[0027] The movements of the actuating cylinder(s) can be regulated by varying the speed of the electric motor(s), which makes it possible to do without a proportional distributor.

[0028] The hydraulic circuit may be free of a distributor when an oil circulation system is provided for each actuating cylinder of the handling system by directly connecting the actuating cylinder to the corresponding oil circulation cylinder. The hydraulic circuit then consists of as many separate sub-circuits as there are oil circulation systems.

[0029] According to one embodiment, the machine includes a ground movement system, such as wheels, and an electric motor for driving the ground movement system.

[0030] The invention also relates to a method of controlling at least one hydraulic actuating cylinder, such as a lifting cylinder, of a load or person handling system of a handling machine, the machine comprising a hydraulic circuit; The process includes the following steps: - rotation of an output shaft of an electric motor of the machine, the output shaft being coupled by a mechanical linkage system to a rod of a piston of a hydraulic cylinder, called an oil circulation cylinder, connected to the hydraulic circuit; - transmission of the movement of the output shaft of the electric motor to said piston rod of the oil circulation cylinder by said mechanical linkage system, to move the rod by sliding and thus push into the hydraulic circuit oil present in a chamber of the oil circulation cylinder, in order to circulate the oil in the hydraulic circuit and supply said at least one hydraulic cylinder for actuating the handling system.

[0031] According to one embodiment, the processing unit is configured such that, when the rod of the hydraulic oil circulation cylinder reaches the end of its stroke, the electric motor changes the direction of rotation, thus driving the cylinder rod. in the opposite direction. The end of the stroke is detected, for example, by a sensor. Thus, the processing unit is configured to control the solenoid valve associated with the oil circulation cylinder in order to reverse the suction and supply sides when the cylinder rod changes direction of movement.

[0032] According to one embodiment, the hydraulic cylinder for oil circulation is a double-acting cylinder. The double-acting cylinder allows for an identical flow rate in both directions of movement, for the same engine speed.

[0033] Preferably, the handling machine includes a ground-based drive system that is electric. The electric drive (as opposed to a thermal drive) thus comprises an electric motor and a power battery to supply the electric motor. A hydrogen fuel cell power supply may be provided. Brief description of the drawings

[0034] Other features and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting and should be read in conjunction with the accompanying drawings, on which:

[0035] - [Fig. 1] [Fig. 1] is a perspective view of a handling machine according to a method of implementing the invention;

[0036] - [Fig.2] [Fig.2] is a perspective view of a circulation system oil comprising a hydraulic cylinder and an electric motor whose output shaft is coupled to the cylinder rod by a mechanical linkage system, in a first end position of the rod, for a handling machine according to a first embodiment of the invention, the cylinder of the oil circulation system being connected to the distributor of a hydraulic circuit;

[0037] - [Fig.2A] [Fig.2A] is a schematic of the oil circulation system of [Fig.2], which also shows a solenoid valve associated with the oil circulation cylinder, the handling system comprising several actuation cylinders connected to the distributor;

[0038] - [Fig.3] [Fig.3] is a view of the entire cylinder, electric motor and the mechanical linkage system of the [Fig.2], in a second end position of the rod, opposite to the first end position, for a handling machine according to an embodiment of the invention;

[0039] - [Fig.4] [Fig.4] is a schematic view of a circulation system oil for a handling machine according to another embodiment of the invention, the oil circulation system comprising several assemblies of electric motors and oil circulation cylinders associated with a solenoid valve, the handling system comprising several actuating cylinders each associated with a solenoid valve of a distributor;

[0040] - [Fig. 5] [Fig. 5] is a schematic view of a circulation system oil circulation system for a handling machine according to another embodiment of the invention, the oil circulation system comprising several assemblies of electric motors and oil circulation cylinders, the handling system comprising several actuating cylinders, each directly hydraulically connected to one of the oil circulation cylinders. DETAILED DESCRIPTION

[0041] Embodiments of the invention are described below with reference to the accompanying drawings. In the drawings, the size and relative sizes of the elements may be exaggerated for clarity. Similar numbers refer to similar elements in all drawings. However, the invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0042] A reference throughout the specification to "an embodiment" means that a particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrase "in an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0043] A load or person handling machine 1 is proposed, comprising a chassis 2, a handling system 600, and an actuation system 8, 8', 8" for the handling system. The handling system 600 may, as in the example of [Fig. 1], include an arm 6 actuated by means of a hydraulic cylinder 8, called a lifting cylinder, which forms part of the actuation system. As explained below in the example of [Fig. 1], the actuation system of the handling system 600 also includes a hydraulic tilt cylinder 8' which allows the pivoting of a load holder 14, for example, a tool holder equipped with a tool, mounted articulated to the arm 6. The actuation system may include one or more other cylinders 8'.

[0044] Machine structure

[0045] The handling system 600 can be carried by the chassis 2 directly or indirectly via a turret. The actuation system allows the handling system to be moved relative to the chassis 2 (and, where applicable, relative to the turret). The handling machine is described below in the frame of a 600 handling system carried directly by the chassis but also applies to a 600 handling system carried by the chassis via a turret.

[0046] The handling system 600 can be, as illustrated in [Fig.1], a load handling system, but can also be a person handling system.

[0047] In the example of [Fig. 1], the handling machine is a vehicle with a boom, preferably telescopic, that can be tilted and is equipped with a tool holder to which a tool such as a bucket or forks is coupled. The handling machine may also be a lifting platform, for example with a pendulum boom. Alternatively, the handling machine may be a machine of another type, such as a forklift with a mast.

[0048] The machine also includes a system for moving the chassis on the ground, and a motor (not shown) for controlling the chassis's movement on the ground. According to a preferred embodiment, the motor for moving the chassis on the ground is electric.

[0049] The chassis's ground movement system and the motor thus form at least part of a machine propulsion system. The machine also includes a steering control system for directing the machine's ground movement.

[0050] The chassis's ground movement system may include wheels 3, 4 (or rolling axles) and a motion transmission system for transmitting the motor's rotation to at least some of the wheels. The chassis 2 can thus be, as in the example of [Fig. 1], a rolling chassis.

[0051] The chassis 2 may include a cabin 20 having a door allowing an operator to get into the cabin 20 to operate the machine.

[0052] The handling machine includes a processing unit 10, comprising, for example, a computer, which allows the handling machine to be controlled, and in particular its ground movement and the actuation system of the handling system. The human-machine interface may include one or more control devices, such as a joystick and pedals. In particular, the processing unit 10 allows the control of the electric motor(s) of the oil circulation system 100, and each solenoid valve as detailed below.

[0053] According to one embodiment, an example of which is illustrated in [Fig. 1], the handling system comprises an arm 6, usually called a lifting arm, articulated to the rolling chassis 2 so as to be able to be moved between a lowered position and a raised position. In the case of a mast truck, the handling system comprises a mast equipped with a system of forks mounted to slide along the mast.

[0054] The lifting arm 6 (or handling arm) is mounted on the chassis 2 and is rotatable around a rotation axis 7. In particular, said rotation axis 7 is horizontal when the rolling chassis 2 is resting on a horizontal surface. The arm 6 projects forward from the machine. In one embodiment, the axis 7 is closer to the rear axle than to the front axle of the machine. In other words, the arm can be articulated at the rear of the chassis.

[0055] As illustrated in [Fig. 1], the arm 6 is preferably of the telescopic type. The arm 6 then comprises at least two deployable segments, for example by means of a deployment cylinder, not shown, arranged between the at least two segments. Alternatively, the arm may be a non-telescopic arm.

[0056] As seen in the example of [Fig.1], the cylinder 8 allows the arm 6 to be moved up and down around the horizontal axis 7, under the control of a control element 12, such as a joystick, connected to the processing unit 10. The machine may include a display screen 13 to display information to the user via the processing unit 10.

[0057] The arm 6 is equipped with a load or person handling device 614. The actuation system may also include a cylinder, called a tilt cylinder, which allows the handling device 614 to be rotated relative to the arm 6. In the illustrated example, the handling device 614 includes a load carrier 14, such as a fork or bucket system, which is articulated to the arm 6 by a linkage 15, such as a horizontal pivot axis, preferably via an attachment coupling device, also called a carriage. The load carrier 14 is configured to carry a payload 9.

[0058] The processing unit 10 is configured to control the actuation system. The load carrier 14 may include a tool holder equipped with a tool or a tool directly articulated to the arm.

[0059] The machine includes a hydraulic circuit 140 which supplies the hydraulic cylinder(s) 8, 8' of the handling system's actuation. For this purpose, the hydraulic circuit 140 is equipped with an oil circulation system 100 which provides a source of hydraulic pressure.

[0060] Whereas in the prior art the hydraulic pressure source is usually formed by a motorized hydraulic pump, in the embodiments of the invention, the hydraulic pressure source is pump-free and includes at least one hydraulic cylinder 130, called an oil circulation cylinder, whose piston rod is mechanically engaged with an electric motor 110.

[0061] Oil circulation cylinder

[0062] The hydraulic cylinder 130 comprises a hollow body 131, called a cylinder, and a piston 132 having a rod 1321 and a head 1322 integral with the rod and movable in the cylinder 131.

[0063] As detailed below, the movement of the rod 1321 and therefore of the piston 132 of the hydraulic cylinder 130 for circulation control, makes it possible to push the oil present in a chamber 1301 or 1302 of the cylinder 130 and thus make it circulate in the hydraulic circuit 140 to which one or more hydraulic actuating cylinders 8, 8' (or even 8") are hydraulically connected.

[0064] According to one embodiment, the oil circulation cylinder or cylinders used are so-called "double rod" cylinders. According to this embodiment, the rod 1321 of the oil circulation cylinder or cylinders 130 has a first portion 1321A extending from one side of the piston head 1322 and a second portion 1321B extending from the other side of the piston head 1322.

[0065] Thus, in the end-stroke position of the piston head on either side of the cylinder 131, the volume of the corresponding first chamber 1301 or second chamber 1302 is the same. This ensures the same oil flow on the pressure line P, regardless of the direction of movement of the rod 1321 (i.e., regardless of which cylinder chamber the oil is coming from when it is pushed into the pressure line P during the operation of the electric motor 110), and thus provides consistent control of the cylinder.

[0066] Electric motor

[0067] The electric motor 110 has a rotatable output shaft 111. A mechanical linkage system 120 is configured to transmit the motion of the output shaft 111 of the electric motor 110 to the piston rod of the hydraulic cylinder 130, so that the rotation of the output shaft 111 drives the sliding movement of the rod and thus of the piston of the cylinder 130.

[0068] The output shaft 111 of the electric motor 110 is thus connected by the mechanical linkage system 120 to the rod 1321 of the cylinder 130 in order to move the piston rod of the hydraulic cylinder, and thus circulate the oil in the hydraulic circuit 140 with a minimum of noise compared with a hydraulic pump, and generating less oil temperature rise.

[0069] Mechanical linkage system

[0070] The mechanical linkage system 120 includes an actuating lever 121.

[0071] The actuating lever 121 has a first part connected to the output shaft 111 of the electric motor 110 by a linkage system 151. The linkage system 151 may include, as in the example illustrated in the figures, a nut having a threaded hole that engages with a thread of the output shaft 111 of the electric motor. The nut 151 is hinged to the lever 121 about an axis orthogonal to the axis of the output shaft 111 and to the axis of the lever 121.

[0072] The actuation lever 121 has a second part articulated to a part of the chassis 2 of the machine.

[0073] The part of the machine chassis 2 to which the second part of the actuating lever 121 is articulated may include, as in the example illustrated in the figures, a set of two V-shaped pieces arranged on either side of the plane passing through the axis of the output shaft 111 and the axis of the rod 1321. According to a particular aspect, the electric motor and the cylinder body are mounted articulated to said part of the machine chassis 2.

[0074] The actuating lever 121 has a third part, located between the first and second parts of the lever 121, which is connected to the rod 1321 of the hydraulic cylinder. The third part, located between the first and second parts of the lever 121, is connected to the rod 1321 of the hydraulic cylinder by a linkage system 153 configured to allow the lever 121 to pivot relative to said rod 1321 (around an axis parallel to the pivot axis of the lever 121 relative to the frame 2). In other words, the third part of the actuating lever 121 is articulated to the rod 1321 of the hydraulic cylinder.

[0075] The articulation to the chassis part 2 of the machine of the end of the lever 121 which forms the second part of the lever, is located, with respect to the articulation of the third part of the actuating lever 121 to the rod of the cylinder, on the opposite side to the articulation of the first part of the actuating lever 121 to the output shaft 111 of the electric motor 110.

[0076] Preferably, the cylinder 130 and the electric motor 110 are mounted articulated to the chassis 2 of the machine around an axis parallel to the pivot axis of the lever 121.

[0077] Operation of the electric motor in relation to the hydraulic cylinder rod

[0078] The electric motor 110 is a rotary motor such that the rotation of the output shaft causes the part of the lever connected to this rotary shaft to move forward or backward along the rotary shaft, at the same time as the lever pivots around its part connected to the chassis, which moves the rod of the cylinder connected to the lever.

[0079] Such a mechanical linkage system with a lever articulated to the chassis and connected to the cylinder rod and the electric motor output shaft allows, with limited energy, an increase in the force applied to the rod to move it. This makes it possible to use a lower-power electric motor in a compact overall design while still providing sufficient power to actuate the hydraulic cylinder. And as mentioned above, the elimination of a hydraulic pump reduces noise, which is particularly advantageous in the case of an electric machine.

[0080] Hydraulic circuit

[0081] The hydraulic circuit 140 may include a hydraulic distributor 141 comprising several solenoid valves ([Fig. 2A] and [Fig. 4]). At least one solenoid valve 1411 is connected to a hydraulic control cylinder 8. Preferably, the system actuation includes several hydraulic control cylinders 8, 8' and each hydraulic control cylinder is connected to a solenoid valve 1411, 1412 of the distributor.

[0082] The distributor 141 is connected to a pressure line P connected to the hydraulic cylinder 130 for oil circulation and to a line from the oil reservoir T.

[0083] According to one embodiment and as illustrated in the examples shown in the figures, each hydraulic actuating cylinder 8, 8' is a double-acting cylinder. The two chambers 81, 82; 81', 82' of the cylinder 8, 8' are connected by hydraulic lines to a solenoid valve 1411, 1412 of the distributor 141 which is also connected to the pressure line P and to the oil reservoir line T.

[0084] Each solenoid valve 1411, 1412 is configured to selectively take several states. According to a particular aspect and with reference more specifically to Figures 2 and 4, the states can include: - a state of circulation blockage, in which the solenoid valve is preferably recalled, and in which the lines of the actuating cylinder do not communicate with the pressure line P and the tank line T; - a supply state (in which the solenoid valve can be brought into operation by control of the processing unit 10 shown below), in which the first line of the actuating cylinder 8, 8' and the second line of the actuating cylinder 8, 8' are connected to the pressure line P and the oil reservoir line T respectively (so that the chamber of the cylinder 8, 8' which can be supplied by control of the oil circulation cylinder 130 is the first chamber 81, 81'), which allows the extension of the rod of the corresponding actuating cylinder to be controlled, for example to lower the arm 6 when the actuating cylinder is a lifting cylinder 8 associated with the arm 6;

[0085] - an opposite supply state (in which the solenoid valve can be brought by control of the processing unit 10 shown below), in which the first line and the second line of the actuating cylinder are connected to respectively the line of the tank T and the pressure line P (so that the chamber of the cylinder 8, 8' which is supplied by control of the cylinder 130 is the second chamber 82, 82'), which allows the retraction of the rod of the corresponding actuating cylinder to be controlled, for example to lower the arm 6 when the actuating cylinder is a lifting cylinder 8 associated with the arm 6.

[0086] As illustrated in [Fig. 4], the actuation system may include one or more additional hydraulic cylinders (in addition to cylinders 8, 8'), and each additional hydraulic cylinder may be connected to another solenoid valve of the distributor. The description given above for cylinder 8, 8' associated with solenoid valve 1411, 1412 thus applies to one or more additional cylinders associated with another or other distributor solenoid valves.

[0087] According to one embodiment and as illustrated in the figures, each hydraulic oil circulation cylinder 130 is a double-acting cylinder. The circulation cylinder 130 comprises two chambers 1301, 1302 located on either side of the piston head 1322 (see, for example, [Fig. 2A]). The chambers 1301, 1302 of the cylinder 130 are connected by hydraulic lines to a solenoid valve 134. The solenoid valve 134 is also connected to a line from the oil reservoir T and the pressure line P, which supplies the actuating cylinder(s) 8, 8' via the distributor 141.

[0088] The solenoid valve 134 is configured to selectively assume several states. The states of the solenoid valve 134 may include the following states.

[0089] According to a first state, called the first state of oil circulation, in which the solenoid valve 134 is preferably recalled, the first chamber 1301 of the circulation cylinder 130 and the second chamber 1302 of the cylinder 130 are connected respectively to the pressure line P and the reservoir line T so that when the motor 110 drives the sliding movement of the rod 1321 in the direction of an exit of the rod on the side of the cylinder 131 where the mechanical linkage system 120 is linked to the rod 1321, the oil present in the chamber 1301 is pushed into the pressure line P, which makes it possible to supply the distributor 141 and, depending on the state of the solenoid valves 1411, 1412 of the distributor 141, to supply one or more hydraulic actuating cylinders 8, 8'. In parallel, the second chamber 1302, which is then connected by the solenoid valve 134 to the reservoir T, fills with oil from the reservoir (by suction).

[0090] According to a second state of the solenoid valve 134, called the second oil circulation state, in which the solenoid valve 134 can be brought by control of the processing unit, the first chamber of the oil circulation cylinder 130 and the second chamber of the cylinder 130 are connected respectively to the reservoir line T and the pressure line P, so that, when the motor 110 drives the sliding movement of the rod 1321 in the other direction (opposite direction to the side of the cylinder where the mechanical linkage system 120 is linked to the piston rod 1321), the oil present in the second chamber 1302 is pushed into the pressure line P, which makes it possible to supply the distributor 141 and, depending on the state of the solenoid valves of the distributor 141, to supply one or more hydraulic actuating cylinders 8, 8'.Simultaneously, the first chamber 1301 of the cylinder 130, which is then connected by the solenoid valve 134 to the reservoir T, fills with oil from the reservoir (by suction).

[0091] It can thus be predicted that, once the motor 110 has brought the rod 1321 to the end of its stroke in the direction of a push of oil from the first chamber 1301 towards the line pressure P, while the second chamber 1302 has filled with oil by suction from the reservoir T, the processing unit 10 is configured to reverse the direction of rotation of the motor 110 to move the rod 1321 in the opposite direction and thus bring the rod 1321 to the end of its stroke in the direction of a push of oil from the second chamber 1302 towards the pressure line P, while the first chamber 1301 fills with oil by suction from the reservoir T, and vice versa when the rod has reached the opposite end-of-stroke position.

[0092] In other words, and as illustrated for example in [Fig.2A], the solenoid valve 134 comprises a first port 1341 connected to a first chamber 1301 of the cylinder 130 for oil circulation; a second port 1342 connected to a second chamber 1302 of the cylinder 130 for oil circulation; a third port 134T connected to an oil reservoir T of the hydraulic circuit 140, and a fourth port 1344 connected by a line called the pressure line P to a hydraulic distributor 141 of the hydraulic circuit 140.

[0093] The solenoid valve 134 is then configured to selectively present: - a first configuration (corresponding to said first state of oil circulation), in which the first channel and the fourth channel are connected so that the oil present in the first chamber of the cylinder is able to pass from the first channel to the fourth channel to supply oil to the pressure line P of the hydraulic circuit, and the third channel and the second channel are connected so that oil from the reservoir T is able to be drawn (from the third channel to the second channel) into the second chamber 1302 of the cylinder 130 for oil circulation; - a second configuration (corresponding to the said first state of oil circulation), in which the second and fourth channels are connected so that the oil present in the second chamber of the cylinder is able to pass from the second channel to the fourth channel to supply oil to the pressure line of the hydraulic circuit, and the third and first channels are connected so that oil from the reservoir T is able to be drawn (from the third channel to the first channel) into the first chamber 1301 of the cylinder 130 for oil circulation.

[0094] The electric motor 110 and the oil circulation cylinder 130, which are coupled together by the mechanical linkage system 120, preferably with the solenoid valve 134 which is connected on one side to the pressure line P and the reservoir line T and on the other side to the cylinder 130, thus form an oil circulation unit. According to a particular embodiment and as illustrated for example in [Fig. 4], an additional oil circulation unit is provided comprising the motor 110' and the oil circulation cylinder 130' coupled between them by the mechanical linkage system 120', preferably with the solenoid valve 134' which is connected on one side to the pressure line P and to the reservoir line T and on the other side to the cylinder 130'. Thus the description made previously for the first assembly 110, 130, 120, 134 also applies to this second assembly 110', 130', 120' 134'.

[0095] Such a design, using several additional oil circulation assemblies, allows for a higher flow rate, enabling the simultaneous control of several actuating cylinders, for example, a lifting cylinder 8 and a tilting cylinder 8' for a handling system comprising an arm and a tilting tool holder. It is also possible to use the two assemblies alternately or overlapping to prevent a drop in oil supply when one of the two rods 1321 reaches the end of its stroke and the corresponding assembly must move in the opposite direction.

[0096] According to another embodiment, and as illustrated for example in [Fig. 5], it is possible to dispense with the distributor 141. In this case, the actuating cylinder(s) are connected to a circulating cylinder by a hydraulic circuit. The description given below for the actuating cylinder 8, the hydraulic circuit 140A (hydraulic connection), the circulating cylinder 130, and the mechanical linkage system 120 also applies to the actuating cylinders 8' and 8", the circulating cylinders 130 and 130', the hydraulic circuits 140B and 140C (hydraulic connections), and the mechanical linkage systems 120' and 120". All the separate hydraulic connections 140A, 140B, and 140C can then be considered as forming part of the hydraulic circuit 140.

[0097] The hydraulic connection 140A can be foreseen to include a connecting line from one chamber of the oil circulation cylinder 130 to one chamber of the actuating cylinder 8, and a connecting line from the other chamber of the oil circulation cylinder 130 to the other chamber of the cylinder 8. As mentioned previously, the oil circulation cylinder is controlled by an electric motor whose output shaft is coupled to the cylinder rod by a mechanical linkage system. The description previously given for the electric motor 110, the cylinder 130, and the mechanical linkage system 120 in the case of using a distributor 141 remains applicable to this alternative embodiment in which the circulation cylinder(s) 130 are hydraulically connected directly to the corresponding actuating cylinder 8.

[0098] In the example of [Fig. 5], each cylinder 130, 130', 130" is shown with a rod extending from only one side of the piston head (a so-called "single-rod" cylinder), but it can be envisaged, as before, that the cylinder has a "double rod". In other words, a motor and cylinder assembly can be envisaged with the system of associated mechanical link, for each hydraulic function that uses an actuation cylinder.

[0099] Processing unit

[0100] The processing unit 10 (or control unit) is, for example, in the form of a processor and a data memory in which computer instructions executable by said processor are stored, or in the form of a microcontroller.

[0101] In other words, the described functions can be implemented in the form of a computer program or via hardware components (e.g., programmable gate arrays). In particular, the functions and steps performed by the processing unit, especially for the control of one or each motor or motorization, or of solenoid valves, can be carried out by instruction sets or computer modules implemented in a processor or controller, or by dedicated electronic components or components of the type of field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC).It is also possible to combine computer and electronic components.

[0102] The processing unit is thus an electronic and / or computer unit. When it is specified that said unit is configured to perform a given operation, this means that the unit includes computer instructions and the corresponding means of execution which enable said operation to be carried out and / or that the unit includes corresponding electronic components.

[0103] The invention is not limited to the embodiments illustrated in the drawings.

[0104] Furthermore, the term "including" does not exclude other elements or steps. In addition, features or steps that have been described with reference to one of the embodiments set out above may also be used in combination with other features or steps from other embodiments set out above.

Claims

Demands

1. Load or person handling machine comprising: - a chassis (2) and, carried by the chassis, a load or person handling system (600) comprising a component (6), such as a lifting arm, mounted movable relative to the chassis (2) and actuable by means of an actuation system which includes at least one hydraulic actuation cylinder (8), such as a lifting cylinder; - a hydraulic circuit (140) comprising a system (100) for circulating oil in the hydraulic circuit (140) to supply oil to the hydraulic actuating cylinder (8); characterized in that the oil circulation system (100) comprises: - a hydraulic cylinder (130), called an oil circulation cylinder, comprising a hollow body (131), called a cylinder, and a piston (132), the piston (132) having a rod (1321) and a head (1322) integral with the rod and movable in the cylinder (131); - an electric motor (110) having an output shaft (111) that can be driven in rotation; - a mechanical linkage system (120) configured to transmit the motion of the output shaft (111) of the electric motor (110) to the rod (1321) of the piston of the oil circulation cylinder (130), so that the rotation of the output shaft (111) of the electric motor (110) causes the sliding movement of the rod (1321) and therefore of the head (1322) of the piston (132) relative to the cylinder (131) to circulate the oil in the hydraulic circuit (141) in order to supply said at least one hydraulic cylinder (8) for actuation of the handling system (600).

2. Machine according to claim 1, wherein the mechanical linkage system (120) comprises an actuating lever (121) which has - a first part connected to the output shaft (111) of the electric motor (110) by a linkage system (151), such as a nut having a thread cooperating with a thread of the output shaft (111) of the electric motor (110), the lever (121) being mounted articulated to said linkage system (151) around an axis orthogonal to the axis of the output shaft (111) and to the axis of the lever (121); - a second part articulated (152) to the chassis (2) of the machine; - and a third part, located between the first and second part of the lever (121), which is connected to the rod (1321) of the hydraulic cylinder.

3. Machine according to claim 2, wherein the third part of the lever (121), located between the first and second part of the lever (121), is mounted articulated (153) to the rod (1321) of the hydraulic cylinder.

4. Machine according to any one of the preceding claims, wherein the actuation system includes several hydraulic actuating cylinders (8, 8'), the hydraulic circuit (140) includes a hydraulic distributor (140) which includes several solenoid valves (1411), each solenoid valve being connected on the one hand to a line, called the pressure line (P), connected to the oil circulation system (100), and to a line from an oil reservoir (T), and on the other hand to a line from a first chamber of one of the hydraulic actuating cylinders (8, 8') and to a line from a second chamber of said hydraulic actuating cylinder (8, 8').

5. Machine according to claim 4, wherein the oil circulation system comprises a solenoid valve (134), which includes: - a first port (1341) connected to a first chamber (1301) of the oil circulation cylinder (130); - a second port (1342) connected to a second chamber (1302) of the oil circulation cylinder (130); - a third port (134T) connected to an oil reservoir (T) of the hydraulic circuit (140); - a fourth port (1344) connected to a hydraulic distributor (141) of the hydraulic circuit (140);the solenoid valve (134) being configured to selectively present: a first supply configuration, in which the first channel and the fourth channel are connected so that the oil present in the first chamber of the cylinder is able to pass from the first channel to the fourth channel to supply oil to the pressure line of the hydraulic circuit, and the third channel and the second channel are connected so that oil from the reservoir (T) is able to be drawn into the second chamber (1302) of the cylinder (130) for oil circulation; a second supply configuration, in which the second channel and the fourth channel are connected so that the oil present in the second chamber of the cylinder is able to pass from the second channel to the fourth channel to supply oil to the line; hydraulic circuit pressure, and the third and first ways are connected so that oil from the reservoir (T) is able to be drawn into the first chamber (1301) of the oil circulation cylinder (130).

6. Machine according to claim 5, wherein the oil circulation system comprises an additional assembly of electric motor (110') and hydraulic cylinder (130') for circulation coupled together by a mechanical linkage system (120'), and a solenoid valve (134') which is connected on one side to the pressure line (P) and the reservoir line (T), and on the other side to the hydraulic cylinder (130') for circulation of said additional assembly.

7. A machine according to any one of the preceding claims, wherein, the hydraulic circuit (140) being without a distributor, the oil circulation system comprises several oil circulation assemblies, each comprising a hydraulic oil circulation cylinder (130, 130', 130"), an electric motor (110, 110', 110") and a mechanical linkage system (120, 120', 120"), and the actuation system comprising several hydraulic actuating cylinders (8, 8', 8"), each hydraulic actuating cylinder (8, 8', 8") being associated with one of said oil circulation assemblies, the hydraulic circuit (140) comprising, for each of said hydraulic actuating cylinders (8, 8', 8"), a hydraulic linkage (140A, 140B, 140C) which includes: - a hydraulic line connecting a chamber of the hydraulic actuating cylinder (8, 8', 8") to a chamber of the cylinder (130, 130',130”) for corresponding oil circulation, and - a hydraulic connection line from the other chamber of the hydraulic actuating cylinder (8, 8', 8”) to the other chamber of the cylinder (130, 130', 130”) for corresponding oil circulation.

8. Machine according to any one of the preceding claims, wherein, for the oil circulation cylinder or cylinders (130), the rod (1321) has a first part (1321 A) extending from one side of the piston head (1322) and a second part (1321B) extending from the other side of the piston head (1322).

9. Machine according to any one of the preceding claims, wherein the machine comprises a ground movement system, such as wheels (3, 4), and an electric motor for driving the ground movement system.

10. A method for controlling at least one hydraulic actuating cylinder (8), such as a lifting cylinder, of a load or person handling system (600) of a material handling machine (1), the machine (1) comprising a hydraulic circuit (140); the method comprising the following steps: - rotation of an output shaft (111) of an electric motor (110) of the machine, the output shaft (111) being coupled by a mechanical linkage system (120) to a rod (1321) of a piston (132) of a hydraulic cylinder (130), called an oil circulation cylinder, connected to the hydraulic circuit (140); - transmission of the motion of the output shaft (111) of the electric motor (110) to said rod (1321) of the piston of the oil circulation cylinder by said mechanical linkage system (120), to move the rod (1321) by sliding and thus push into the hydraulic circuit (140) oil present in a chamber (1301, 1302) of the oil circulation cylinder, in order to circulate the oil in the hydraulic circuit (140) and supply said at least one hydraulic actuating cylinder (8) of the handling system (600).

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