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 which includes a member actuable using a hydraulic actuating cylinder (8). The machine comprises a hydraulic oil circulation cylinder (130) and an electric motor (110) which has an output shaft (111) coupled to the rod of the hydraulic oil circulation cylinder by a mechanical connection system (120) to slidably move 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 member of the handling system. The invention also relates to a corresponding control method. Figure for 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 PRIOR ART

[0002] The state of the art discloses handling machines comprising a handling system, such as a lifting arm provided with an apron equipped with a tool, and a system for actuating the handling system comprising one or more hydraulic actuating cylinders. The lifting arm of a machine with a tilting arm can, for example, be pivotally actuated between a lowered position and a raised position using a lifting cylinder, and it may be provided that the assembly of the apron and the tool can be tilted relative to the arm by actuating a tilting cylinder.

[0003] Usually, a cylinder of the actuating system is controlled by a hydraulic circuit which comprises a pump for pressurizing the oil in the hydraulic circuit to circulate it. The hydraulic circuit comprises a supply line whose opening can be controlled by a solenoid valve to allow the pressurized oil to be directed to the actuating cylinder in order to supply and thus actuate the actuating cylinder to move a member of the associated handling system.

[0004] However, the hydraulic pump is a component whose operation is noisy. The noise of the hydraulic pump is even more noticeable in the case where the handling machine includes an electric motor since the electric motor is relatively quiet compared to a thermal motor of the diesel or gasoline type.

[0005] The aim of the present invention is to propose a new machine and corresponding control method making it possible to overcome all or part of the problems set out above. Summary of the invention

[0006] To this end, the invention relates to a load or person handling machine comprising: - a chassis and, carried by the chassis, a load or person handling system comprising a member, such as a lifting arm, mounted to move relative to the chassis and operable using an actuation system which comprises at least one hydraulic actuation cylinder, such as a lifting cylinder; - a hydraulic circuit comprising 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 secured to the rod and movable in the cylinder; - an electric motor having a rotatable output shaft; - a mechanical connection system configured to transmit the movement 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 actuating the handling system.

[0007] Compared with the state of the art where the oil supply to a hydraulic cylinder for actuating the handling system is controlled by a hydraulic pump, having instead of the pump a hydraulic cylinder (said oil circulation cylinder) and a mechanical connection system to directly mechanically transmit the movement of the electric motor to the rod of the hydraulic oil circulation cylinder, avoids having a noisy, bulky and energy-consuming system, which 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 oil circulation system of the machine. The movement of the piston of the oil circulation cylinder using the electric motor via the mechanical connection in fact makes it possible to power and therefore control one or more hydraulic cylinders of the actuation system of the handling system, i.e. another or other hydraulic members of the machine connected to one or more members of the handling system.

[0009] Such a design using an electric motor assembly mechanically connected to the rod of a hydraulic cylinder, also makes it possible to use the electric motor more easily at high operating speeds compared to an architecture using a pump.

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

[0011] According to a preferred embodiment, the or each actuating and / or oil circulation cylinder is a double-acting cylinder. According to a less advantageously, the double-acting cylinder could be replaced by two single-acting cylinders. According to a particular embodiment, the cylinder is a double-acting cylinder with two rod sections which extend on either side of the piston head.

[0012] According to one embodiment, the mechanical connection system comprises an actuating lever which has: - a first part connected to the output shaft of the electric motor by a connection 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 connection 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 connection 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 jack); - a second articulated part (pivot link) to the machine frame; - and a third part, located between the first and second part of the lever, which is connected to the rod of the hydraulic cylinder.

[0013] The different parts of the lever are integral with 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 rotary shaft to move, by means of a nut whose thread is engaged with the thread of the output shaft. The nut is coupled to the lever with a mobility of articulation of the lever relative to the nut. Thus the lever can move forward or backward along the rotary shaft according to the direction of rotation of the motor, and this at the same time as the lever pivots around its axis of connection to the chassis, which causes the sliding movement, relative to the cylinder, of the rod of the jack which is connected to the lever.

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

[0016] In other words, when the lever is moved by the electric motor, the arrangement of the lever makes it possible to benefit from a lever arm which makes it possible to obtain a significant force on the rod of the hydraulic circulation control cylinder, which makes it possible not to have to oversize the electric motor and therefore makes it possible to limit the size and cost of the electric motor. The oil contained in the cylinder will then supply the hydraulic circuit of the machine to which one or more hydraulic cylinders of the actuation system of the handling 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 connection) to the rod of the hydraulic cylinder.

[0018] According to one embodiment, the hydraulic circuit comprises a hydraulic distributor which comprises several solenoid valves, at least one, preferably each, solenoid valve being connected on the one hand to a line, called a 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 comprises a hydraulic distributor which comprises several solenoid valves, each solenoid valve being connected on the one hand to a line, called a 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 one of the hydraulic actuation cylinders and to a line of a second chamber of said hydraulic actuation cylinder.

[0020] According to one embodiment, the oil circulation system comprises 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 channel connected to an oil tank of the hydraulic circuit, - a fourth way connected (by a line called 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 path and the fourth path are communicated so that the oil present in the first chamber of the cylinder is able to pass from the first path to the fourth path to supply oil to the pressure line of the hydraulic circuit, and the third path and the second path are communicated so that oil from the reservoir is able to be sucked (from the third path to the second path) into the second chamber of the oil circulation cylinder; a second supply configuration, in which the second path and the fourth path are connected so that the oil present in the second chamber of the cylinder is able to pass from the second path to the fourth path to supply oil to the pressure line of the hydraulic circuit, and the third path and the first path are connected so that oil from the reservoir is capable of being sucked (from the third way to the first way) into the first chamber of the oil circulation cylinder.

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

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

[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 connection system, and the actuation system comprising several hydraulic actuation cylinders, each hydraulic actuation cylinder being associated with one of said oil circulation assemblies, the hydraulic circuit comprising, for each of said hydraulic actuation cylinders, a hydraulic connection which comprises: - a hydraulic line connecting a chamber of the hydraulic actuating cylinder to a chamber of the corresponding oil circulation cylinder, and - a hydraulic line connecting the other chamber of the hydraulic actuating cylinder to the other chamber of the corresponding oil circulation cylinder.

[0024] It is thus possible to provide a direct hydraulic supply circuit between the hydraulic oil circulation cylinder 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 formed of an electric motor and a hydraulic oil circulation cylinder which is mechanically connected to the electric motor. Each member of the assembly can be of reduced size, with the oil circulation cylinder directly connected to one of the hydraulic cylinders of the machine.

[0026] Whatever 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 handling does not require stopping movement because the assemblies can be controlled in such a way as to take turns, with or without overlapping operating phases. The electrical consumption can be optimized according to the required movement speed, by combining the start-up of one or more assemblies. If necessary, it is possible to use a simple distributor whose function is to manage the accumulation or not of the flows and to 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 or each electric motor, which makes it possible to dispense with the need for a proportional distributor.

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

[0029] According to one embodiment, the machine comprises 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 for 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 method comprising the following steps: - rotating an output shaft of an electric motor of the machine, the output shaft being coupled by a mechanical connection 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 connection system, to slidably move the rod 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 so that, when the rod of the hydraulic oil circulation cylinder reaches the end of its stroke, the electric motor changes direction of rotation, thus driving the cylinder rod in the opposite direction. The end of travel is, for example, detected 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 oil circulation cylinder is a double-acting cylinder. The double-acting cylinder allows for an identical flow rate in both directions of movement, for an identical engine speed.

[0033] Preferably, the handling machine comprises a motorization system for ground movement which is an electric motorization. The electric motorization (as opposed to a thermal motorization) thus comprises an electric motor and a power battery to supply the electric motor. A hydrogen fuel cell electrical power source may be provided. Brief description of the drawings

[0034] Other characteristics and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting and must be read in conjunction with the appended drawings, in which:

[0035] - [Fig.l] [Fig.l] is a perspective view of a handling machine according to a embodiment of 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 connection 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 actuating cylinders connected to the distributor;

[0038] - [Fig.3] [Fig.3] is a view of the entire cylinder, electric motor and mechanical connection system of [Fig.2], in a second end position of the rod, opposite 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 motor and oil circulation cylinder 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 electric motor and oil circulation cylinder assemblies, the handling system comprising several actuating cylinders each hydraulically connected directly 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. Like numerals refer to like elements throughout the drawings. However, the invention may be embodied 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 connection with an embodiment is included in at least one embodiment of the present invention. Thus, the occurrence of the phrase "in an embodiment" at various locations 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 machine 1 for handling loads or people is proposed, comprising a chassis 2, a handling system 600 and an actuation system 8, 8', 8" of the handling system. The handling system 600 can thus, as in the example of [Fig.l], comprise an arm 6 actuable using a hydraulic cylinder 8, called a lifting cylinder, and forming part of the actuation system. As explained below in the example of [Fig.l], the actuation system of the handling system 600 also comprises a hydraulic tilt cylinder 8' which makes it possible to actuate the pivoting of a load carrier 14, for example a tool carrier equipped with a tool, mounted articulated on the arm 6. The actuation system can comprise 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 makes it possible to move said handling system relative to the chassis 2 (and where appropriate relative to the turret). The handling machine is described below in the context 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 may be, as illustrated in [Fig.l], a load handling system, but may also be a person handling system.

[0047] In the example of [Fig.l], the handling machine is a vehicle with an arm, preferably telescopic, tilting, equipped with a tool holder to which a tool such as a bucket or forks is coupled. The handling machine can also be a lifting platform, for example with a pendulum arm. Alternatively, the handling machine can be a machine of another type, such as a masted forklift.

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

[0049] The chassis ground movement system and the motorization thus form at least part of a propulsion system of the machine. The machine also comprises a direction control system for directing the ground movement of the machine.

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

[0051] The chassis 2 may comprise a cabin 20 having a door allowing an operator to sit in the cabin 20 to operate the machine.

[0052] The handling machine includes a processing unit 10, comprising for example a computer, which makes it possible to control the handling machine, and in particular to control the movement on the ground of the machine and the actuation system of the handling system. The human-machine interface may comprise one or more control members, such as a joystick and pedals. In particular, the processing unit 10 makes it possible to control the or each electric motor of the oil circulation system 100, and each solenoid valve has the following details.

[0053] According to one embodiment, an example of which is illustrated in [Fig.l], 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 so-called lowered position and a raised position. In the case of a masted truck, the handling system comprises a mast equipped with a fork system mounted to slide along the mast.

[0054] The lifting arm 6 (or handling arm) is mounted on the chassis 2 and can be oriented around an axis of rotation 7. In particular, said axis of rotation 7 is horizontal when the rolling chassis 2 is resting on horizontal ground. The arm 6 projects towards the front of the machine. According to 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 mounted articulated at the rear of the chassis.

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

[0056] As visible in the example of [Fig.l], the jack 8 makes it possible to move the arm 6 upwards and downwards around the horizontal axis 7, under the control of a control member 12, such as a joystick, connected to the processing unit 10. The machine may comprise a display screen 13 for displaying 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 comprise a cylinder, called a tilt cylinder, which makes it possible to pivot the handling device 614 relative to the arm 6. In the example illustrated, the handling device 614 comprises a load carrier 14, such as a fork or bucket system, which is articulated to the arm 6 by a connection 15, such as a horizontal pivot axis, preferably via an accessory coupling device, also called an apron. 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 comprise a tool carrier equipped with a tool or a tool directly articulated to the arm.

[0059] The machine comprises a hydraulic circuit 140 which makes it possible to supply the hydraulic cylinder(s) 8, 8' for actuating the actuating system of the handling system. For this purpose, the hydraulic circuit 140 is provided with a system 100 for circulating oil forming a source of hydraulic pressure.

[0060] Whereas in the state of the art the source of hydraulic pressure is usually formed by a motorized hydraulic pump, in the embodiments of the invention, the source of hydraulic pressure is free of pump and comprises at least one hydraulic cylinder 130, called an oil circulation cylinder, the piston rod of which 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 secured to 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 circulation control cylinder 130, makes it possible to push the oil present in a chamber 1301 or 1302 of the cylinder 130 and thus to circulate it 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 or each oil circulation cylinder used is a so-called “double rod” cylinder. According to this embodiment, the rod 1321 of the or each oil circulation cylinder 130 has a first part 1321A which extends on one side of the head of the piston 1322 and a second part 1321B which extends on the other side of the head of the piston 1322.

[0065] Thus, in the end-of-stroke position of the piston head on one side or the other of the cylinder 131, the volume of the first chamber 1301 or of the corresponding second chamber 1302 is the same. This makes it possible to benefit from the same oil flow rate on the pressure line P, regardless of the direction of movement of the rod 1321 (i.e. regardless of the chamber of the cylinder from which the oil comes which is pushed into the pressure line P during operation of the electric motor 110), and thus a homogeneous control of the cylinder.

[0066] Electric motor

[0067] The electric motor 110 has an output shaft 111 that can be driven in rotation. A mechanical connection system 120 is configured to transmit the movement 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 makes it possible to cause the sliding movement of the rod and therefore of the piston of the cylinder 130.

[0068] The output shaft 111 of the electric motor 110 is thus connected by the mechanical connection system 120 to the rod 1321 of the cylinder 130 in order to be able 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 to a hydraulic pump, and by generating less rise in oil temperature.

[0069] Mechanical connection system

[0070] The mechanical connection system 120 comprises 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 connecting system 151. The connecting system 151 may comprise, as in the example illustrated in the figures, a nut having a thread cooperating with a thread of the output shaft 111 of the electric motor. The nut 151 is mounted articulated to the lever 121 around an axis orthogonal to the axis of the output shaft 111 and to the axis of the lever 121.

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

[0073] The part of the chassis 2 of the machine to which the second part of the actuating lever 121 is articulated may comprise, as in the example illustrated in the figures, a set of two V-shaped parts 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 body of the cylinder are mounted articulated to said part of the chassis 2 of the machine.

[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 connecting 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 chassis 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 part of the chassis 2 of the machine of the end of the lever 121 which forms the second part of the lever, is located, relative to the articulation of the third part of the actuating lever 121 to the rod of the jack, on the side opposite the articulation of the first part of the actuating lever 121 to the output shaft 111 of the electric motor 110.

[0076] Preferably, the jack 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 connection with the hydraulic cylinder rod

[0078] The electric motor 110 is a rotary motor such that the rotation of the output shaft causes the portion 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 portion connected to the chassis, which moves the cylinder rod connected to the lever.

[0079] Such a mechanical connection system with a lever articulated to the chassis, and linked to the cylinder rod and to the output shaft of the electric motor, allows with limited energy to increase the force applied to the rod to move it, which allows to use an electric motor of reduced power in a reduced overall size while benefiting from sufficient power to actuate the hydraulic cylinder. And as recalled above, the fact of being able to do without a hydraulic pump makes it possible to reduce noise, which is particularly advantageous in the case of an electric machine.

[0080] Hydraulic circuit

[0081] The hydraulic circuit 140 may comprise 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 actuating system comprises 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 circulating oil and to a line of the oil reservoir T.

[0083] According to one embodiment and as in the examples illustrated 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 particular reference to Figures 2 and 4, the states may include: - a circulation blockage state, 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 reservoir line T; - a power supply state (in which the solenoid valve can be brought by control of the processing unit 10 presented below), in which the first line of the actuating cylinder 8, 8' and the second line of the actuating cylinder 8, 8' are put into communication with the pressure line P and the line of the oil reservoir 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 makes it possible to control the output of the rod of the corresponding actuating cylinder, for example to lower the arm 6 when the actuating cylinder is a lifting cylinder 8 associated with the arm 6;

[0085] - an opposite power supply state (into which the solenoid valve can be brought by control of the processing unit 10 presented below), in which the first line and the second line of the actuating cylinder are placed in communication with respectively the line of the reservoir T and the pressure line P (so that the chamber of the cylinder 8, 8' which can be supplied by control of the cylinder 130 is the second chamber 82, 82'), which makes it possible to control the retraction of the rod of the corresponding actuating cylinder, 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 comprise one or more additional hydraulic cylinders (in addition to the cylinders 8, 8'), and the or each additional hydraulic cylinder may be connected to another solenoid valve of the distributor. The description given above for the cylinder 8, 8' associated with the solenoid valve 1411, 1412 thus applies to one or more other cylinders associated with another or other distributor solenoid valves.

[0087] According to one embodiment and as in the examples 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 of the oil reservoir T and the pressure line P which makes it possible to supply 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 oil circulation state, 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 placed in communication with the pressure line P and the reservoir line T respectively so that when the motor 110 causes 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 connection system 120 is connected 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 tank T fills with oil from the tank (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 command from the processing unit, the first chamber of the oil circulation cylinder 130 and the second chamber of the cylinder 130 are placed in communication with the reservoir line T and the pressure line P respectively, so that, when the motor 110 causes the sliding movement of the rod 1321 in the other direction (direction opposite to the side of the cylinder where the mechanical connection system 120 is connected to the rod 1321 of the piston), 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'.In parallel, 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 provided that, once the motor 110 has brought the rod 1321 to the end of its travel in the direction of a thrust of the oil from the first chamber 1301 towards the line of 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 pushing the oil from the second chamber 1302 towards the pressure line P, while the first chamber 1301 is filled 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 for example illustrated in [Fig.2A], the solenoid valve 134 comprises a first path 1341 connected to a first chamber 1301 of the oil circulation cylinder 130; a second path 1342 connected to a second chamber 1302 of the oil circulation cylinder 130; a third path 134T connected to an oil reservoir T of the hydraulic circuit 140, and a fourth path 1344 connected by a line called 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 oil circulation state), in which the first path and the fourth path are placed in communication so that the oil present in the first chamber of the cylinder is able to pass from the first path to the fourth path to supply oil to the pressure line P of the hydraulic circuit, and the third path and the second path are placed in communication so that oil from the reservoir T is able to be sucked (from the third path to the second path) into the second chamber 1302 of the oil circulation cylinder 130; - a second configuration (corresponding to said first oil circulation state), in which the second path and the fourth path are placed in communication so that the oil present in the second chamber of the cylinder is able to pass from the second path to the fourth path to supply oil to the pressure line of the hydraulic circuit, and the third path and the first path are placed in communication so that oil from the reservoir T is able to be sucked (from the third path to the first path) into the first chamber 1301 of the oil circulation cylinder 130.

[0094] The electric motor 110 and the oil circulation cylinder 130, which are coupled together by the mechanical connection system 120, preferably with the solenoid valve 134 which is connected on the one hand to the pressure line P and to the reservoir line T and on the other hand to the cylinder 130, thus form an oil circulation assembly. According to a particular embodiment and as for example illustrated in [Fig. 4], an additional oil circulation assembly is provided comprising the motor 110' and the oil circulation cylinder 130' coupled together them by the mechanical connection system 120', preferably with the solenoid valve 134' which is connected on the one hand to the pressure line P and to the reservoir line T and on the other hand to the cylinder 130'. Thus the description previously made 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 makes it possible to benefit from a greater flow rate to be able to control several actuating cylinders at the same time, 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 by overlapping, in order to avoid a drop in the oil supply, when one of the two rods 1321 reaches the end of its travel and the corresponding assembly must move in the opposite direction.

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

[0097] It can be provided that the hydraulic connection 140A comprises a line for connecting one chamber of the oil circulation cylinder 130 to one chamber of the actuating cylinder 8 and a line for connecting the other chamber of the oil circulation cylinder 130 to the other chamber of the cylinder 8. As recalled previously, the oil circulation cylinder is controlled by an electric motor whose output shaft is coupled to the cylinder rod by a mechanical connection system. The description previously given for the electric motor 110, the cylinder 130 and the mechanical connection system 120 in the case of using a distributor 141, remains applicable to this other embodiment for which the or each circulation cylinder 130 is 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 which extends on one side only of the piston head (so-called “single rod” cylinder) but it is possible, as previously, to provide for the cylinder to have a “double rod”. In other words, it is possible to provide a motor and cylinder assembly with the system of associated mechanical connection, for each hydraulic function which uses an actuating 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, in particular for controlling one or each motor or motorization, solenoid valves, can be performed by instruction sets or computer modules implemented in a processor or controller or be performed by dedicated electronic components or components of the programmable logic circuit type (or FPGA which is the acronym for field-programmable gate array, which literally corresponds to in-situ programmable gate array) or of the application-specific integrated circuit type (or ASIC which is the acronym for application-specific integrated circuit, which literally corresponds to application-specific integrated circuit).It is also possible to combine computer parts and electronic parts.

[0102] The processing unit is thus an electronic and / or computer unit. When it is specified that said unit is configured to carry out a given operation, this means that the unit comprises computer instructions and the corresponding execution means which make it possible to carry out said operation and / or that the unit comprises corresponding electronic components.

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

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

Claims

Claims

1. Load or person handling machine comprising: - a chassis (2) and, carried by the chassis, a load or person handling system (600) comprising a member (6), such as a lifting arm, mounted to move relative to the chassis (2) and operable using an actuation system which comprises 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 enable the hydraulic actuating cylinder (8) to be supplied with oil; 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) which can be driven in rotation; - a mechanical connection system (120) configured to transmit the movement 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 actuating the handling system (600).

2. Machine according to claim 1, in which the mechanical connection 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 connection 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 connection system (151) around an axis orthogonal to the axis of the output shaft (111) and to the axis of the lever (121); - a second articulated part (152) to the frame (2) of the machine; - and 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.

3. Machine according to claim 2, in which 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, in which, the actuation system comprising several hydraulic actuation cylinders (8, 8'), the hydraulic circuit (140) comprises a hydraulic distributor (140) which comprises several solenoid valves (1411), each solenoid valve being connected on the one hand to a line, called pressure line (P), connected to the oil circulation system (100), and to a line of an oil reservoir (T), and on the other hand to a line of a first chamber of one of the hydraulic actuation cylinders (8, 8') and to a line of a second chamber of said hydraulic actuation cylinder (8, 8').

5. Machine according to claim 4, wherein the oil circulation system comprises a solenoid valve (134), which comprises: - a first way (1341) connected to a first chamber (1301) of the oil circulation cylinder (130); - a second way (1342) connected to a second chamber (1302) of the oil circulation cylinder (130); - a third way (134T) connected to an oil reservoir (T) of the hydraulic circuit (140); - a fourth way (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 way and the fourth way are put into communication 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 way and the second way are put into communication so that oil from the reservoir (T) is able to be sucked into the second chamber (1302) of the oil circulation cylinder (130); a second supply configuration, in which the second way and the fourth way are put into communication, so that the oil present in the second chamber of the cylinder is able to pass from the second way to the fourth way to supply oil to the pressure line of the hydraulic circuit; pressure of the hydraulic circuit, and the third way and the first way are put into communication so that oil from the reservoir (T) is able to be sucked into the first chamber (1301) of the oil circulation cylinder (130).

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

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

8. Machine according to any one of the preceding claims, in which, for the or each oil circulation cylinder (130), the rod (1321) has a first part (1321 A) which extends on one side of the head of the piston (1322) and a second part (1321B) which extends on the other side of the head of the piston (1322).

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

10. 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 handling machine (1), the machine (1) comprising a hydraulic circuit (140); the method comprising the following steps: - rotating an output shaft (111) of an electric motor (110) of the machine, the output shaft (111) being coupled by a mechanical connection 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 movement 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 connection system (120), to slidably move the rod (1321) 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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