WO2007125120A1 - Hydraulic machine jack control device and its applications - Google Patents

Abstract

According to the invention, the device is equipped with a load sensor (50) for a given position of the machine jack. The jack can be operated by a lever (18) via a hydraulic circuit (15) and a hydraulic sequence valve (11). A supplementary manual control (82) device, an automatic control module of input (17c, 17d) for low pressure control of the valve connected to the supplementary device (82) and the sensor (50), as well as means (30c, 30d) of hydraulic point switching of input (17c, 17d), controlled by the module (70a)are foreseen.

Description

 Hydraulic control device for machine cylinders and its applications

The invention relates to a hydraulic control device for a cylinder of a machine intended to be installed on a vehicle.

The machines concerned are for example, but not exclusively, handling loaders, and also the tool hitchings.

A charger is intended to be installed on a vehicle, such as for example a tractor, and is designed to be able to handle various materials, such as for example in a farm, straw, hay, manure, soil , fertilizers, cereals, beets, potatoes, silage.

For this purpose, the loader comprises a stretcher that can be lifted and lowered relative to the vehicle by first hydraulic cylinders and, at the end of the stretcher, a tool that can be moved relative to the stretcher by second hydraulic cylinders. Thus, the tool may be for example a bucket, a claw, a fork, or combined tools, such as clamshells for example.

In general, the tool has in relation to the stretcher a raised position, said recess, and a lowered position, said spill. To control the movement of the cylinders, there is known a device using a movable lever or multifunction lever on the dashboard of the vehicle. This lever is connected by a low-pressure hydraulic circuit to a hydraulic cylinder actuator and can be manually moved forward and backward to cause lowering and lifting of the stretcher, as well as to the right and to the left to control spillage and tipping of the tool.

The control device of the machine, and in particular of the loader, must fulfill many requirements. It must be ergonomic, allow easy and fast handling of the tool, while being multifunction.

In addition, the person driving the vehicle must be able to control the loader while the vehicle is moving. Control devices using software means are known for controlling the dispenser from the joystick. Such computer devices, however, have problems of reliability of the control, electromagnetic compatibility of the electronic interface at the distributor, and sensitivity to other external conditions such as moisture and dirt.

Mechanically operated actuator control devices of the dispenser are also known, but require the muscular force of the user to pull on, which is tiring. In addition, the cables wear out quickly and must be changed regularly. It is thus currently discouraged to resort to cable or software devices and it is currently preferred to focus on hydraulically controlled devices, for their reliability and relatively low cost of manufacture and maintenance.

The invention aims to obtain a hydraulic control device having improved ergonomics while meeting these requirements.

For this purpose, a first object of the invention is a hydraulic control device of at least one cylinder of a machine intended to be installed on a vehicle, the actuator being operable in a first direction of movement of a first part. mechanical mechanism of the machine with respect to a second mechanical part articulated on the first part and in the second direction opposite to the first direction, the device comprising a high pressure hydraulic distributor, which is connected to the jack and which comprises a coupling module to a circuit low-pressure hydraulic control device from a handle, the coupling module comprising at least a first actuator movement control input in the first direction by receiving therein low pressure hydraulic fluid via the low pressure hydraulic control circuit and at least one second cylinder displacement control input in the second direction by receiving therein low pressure hydraulic fluid via the hydraulic control circuit low pressure, the lever having at least a first low pressure hydraulic fluid outlet, adapted to be activated by movement of the handle in a first corresponding prescribed direction for sending low pressure hydraulic fluid to the first control input, and minus a second output of low pressure hydraulic fluid, adapted to be activated by moving the handle in a second corresponding prescribed direction for sending hydraulic fluid to the second control input, characterized in that the control device further comprises : at least one cylinder position sensor, capable of providing a first re detection indication when the cylinder has passed a predetermined position in the first direction and a second detection indication when said cylinder has passed said predetermined position in the second direction, an additional manual control member, able to be actuated is in a state of control, either in a state of no control, an automatic control module, connected to the cylinder position sensor and the additional manual control member, and able to generate in the presence of the control state and the first detection indication a first automatic command on a first access, and in the presence of the control state and the second detection indication a second automatic control on a second access, a first hydraulic switching means of the first input hydraulic control, either on an automatic low-pressure fluid supply duct in the presence of the second automatic control on the second access, either on the first hydraulic fluid outlet in the absence of the second automatic control on the second access, a second hydraulic switching means of the second hydraulic control input, or on the automatic low pressure fluid supply duct in the presence of the first automatic control on the first access, or on the second hydraulic fluid outlet in the absence of the first automatic control on the first access.

According to other features of the invention,

- The additional manual control member is formed by a push button, whose control state corresponds to pressing the button and whose state of absence of control corresponds to the release of the button;

- the push button is provided on the controller;

the automatic control module is electric and comprises electrical inputs for receiving the status of the additional manual control element and the indication of the sensor, the hydraulic switching means are formed by solenoid valves, whose said electrical accesses are connected to electrical outputs controlling the position of the solenoid valves; - The cylinder position sensor is fixed on a fixed support relative to the cylinder shaft and is a proximity sensor of a workpiece driven by the rod of the cylinder, movable relative to the support and located in front of the sensor from said predetermined position in one of the first and second directions and not facing the sensor otherwise; the automatic control module comprises a D type latch for storing the last indication of the cylinder position sensor;

the automatic control module comprises: a first generation transistor, by its main conducting channel, of the first automatic control or its absence on a first control output of the first access, as a function of the signal present on a channel control input, connected to the next state output complementary to the flip-flop, a second generation transistor, by its main conduction path, of the second automatic command or its absence on a second command output the second access, according to the signal present on a channel control input, connected to the next state output of the flip-flop, a third transistor, whose main conduction path is arranged to allow, in case of conduction, supplying current to the main conduction path of the first and second transistors, and whose channel control input is connected to an electrical input for receiving the state of the additional manual control element, for controlling the conduction of the main channel of the third transistor for the control state of the additional manual control element and the non-conduction of the main track of the third tr nsistor for the state of absence of control of the additional manual control member, means being provided on the control inputs and on the status outputs of the rocker so that these outputs latch select by their next state and their next state complementary conduction of the main channel of the first or second transistor with the non-conduction of the main channel of the second or first transistor in case of conduction of the main channel of the third transistor.

The invention also relates to applications of the hydraulic control device as described above to a material handling loader, the material handling loader comprising a frame intended to be fixed to the vehicle, a stretcher rotating relative to the frame, a tool holder rotatable relative to the stretcher, at least a first hydraulic cylinder for moving the stretcher relative to the frame in the first direction of lifting or in the second opposite direction of lowering, and at least one second hydraulic cylinder for moving the tool holder relative to the stretcher in the first direction of lifting or in the second opposite direction of lowering, characterized in that the control device is applied to the first cylinder and / or the second cylinder.

In another application of the hydraulic control device as described above to a machine comprising at least a first cylinder and at least a second cylinder, the first cylinder being operable in a first direction of movement of a first mechanical part of the machine relative to a second mechanical part articulated on the first part and in the second direction opposite to the first direction, the second actuator being operable in a first direction of movement of a third mechanical part of the machine relative to the second mechanical part and in the second direction opposite to the first direction, the control device is applied to the first jack and the second jack.

In this application, for example a single additional manual control member is provided for the control of the automatic control module associated with the first cylinder and for the control of the automatic control module associated with the second cylinder.

In another application of the hydraulic control device as described above to a material handling loader, the handling loader comprising a frame intended to be fixed to the vehicle, a stretcher rotatable relative to the frame, a rotary tool holder relative to the stretcher, a tool, which is mounted on the tool holder and which has a second movable part hinged to a first portion of the tool, at least a first hydraulic cylinder for moving the stretcher relative to the frame in the first direction of the lifting or in the second opposite direction of lowering, at least a second hydraulic cylinder of moving the tool holder relative to the stretcher in the first direction of lifting or in the second opposite direction of lowering, and on the tool at least a third hydraulic cylinder for moving the second part of the tool relative to its first part, the control device is applied to the third cylinder.

In another application of the hydraulic control device as described above to a lift for carrying a tool, the lift comprising at least one lifting arm articulated relative to a frame intended to be fixed to the vehicle, and at least one cylinder for moving the arm relative to the frame in the first direction of lifting or in the second opposite direction of lowering, the control device is applied to said cylinder. In another application of the hydraulic control device as described above with a lift, the lift comprising at least one lifting arm hinged relative to a frame intended to be fixed to the vehicle, at least one hydraulic cylinder for moving the arm relative to the frame in the first direction of lifting or in the second opposite direction of lowering, a rotary tool on the arm and at least a second hydraulic cylinder moving in the first direction of lifting or in the second opposite direction of lowering , the control device is applied to the second cylinder. The invention will be better understood on reading the description which follows, given solely by way of non-limiting example with reference to the accompanying drawings, in which:

- Figure 1 shows schematically in side view a tractor on which are mounted a loader and a loader control device according to the invention,

FIG. 2 is a block diagram of the hydraulic control device, according to one embodiment of the invention, FIG. 3 is a circuit diagram of an automatic electrical control circuit used in the hydraulic control device, according to one embodiment of the invention, and

- Figure 4 shows schematically in side view a tractor lift on which can be implemented the control device according to the invention.

In Figure 1, the loader 1 comprises a stretcher 2 of known type, formed of two lateral arms each bent. The stretcher 2 has at one end 21 a rotary joint 3 on the upper part 41 of a coupling frame 4 attached to a rolling vehicle, such as for example the front of a tractor in the case represented by a front loader. At its other end 22, the stretcher 2 comprises a toolholder 6 to which a tool 7 can be fixed, such as for example in Figure 1 a bucket 71 with claws 72. The tool holder 6 is articulated by an axis of rotation 8 with respect to the stretcher 2.

A first lifting jack 9 is hinged at one end 91 to a lower portion 42 of the frame 4 and at another end 92 to an intermediate portion 23 of the stretcher 2, located between the ends 21 and 22 thereof, for example at the 2. The end 91 or 92 of the first jack 9 is provided on its rod 93 movable relative to its barrel 94 having the other end 92 or 91. Such a lifting cylinder 9 is for example provided for each lateral arm of the stretcher 2. The stretcher 2 thus has an extreme lifting position and an extreme lowering position relative to the frame 4. A second jack 10 is tipped hinge end 101 on the part intermediate 23 of the stretcher 2 and another end 102 on a point 61 of action of the tool holder 6, located at a distance from the axis 8, to move the tool holder 6 relative to the stretcher 2 upwards in the sense of digging or down in the direction of spill or tipping. This point of action 61 is formed by the axis of a rocker arm 62 articulated by another remote axis 63 on the stretcher 22, the axis 62 also connecting the jack 10 to a rod 64 acting on the tool holder 6 away from the axis 8. The end 101 or 102 of the second cylinder 10 is provided on its rod 103 movable relative to its shaft 104 having the other end 102 or 101. Such a tipping cylinder 10 is for example provided for each side arm of the stretcher 2. The tool holder 6 thus comprises an extreme raised position or digging and an extreme lowered or spill position with respect to the stretcher 2.

The cylinders 9, 10 are for example double acting in the following, but could also be simple effect with the corresponding adaptations.

In FIG. 2, the control device for the lifting and tipping cylinders 9, 10 comprises a high-pressure hydraulic fluid distributor 11 to the cylinders 9, 10, the distributor 11 having for this purpose two outlets 12a, 12b connected by hydraulic conduits not shown on either side of the piston of the cylinder 9 for the displacement of its rod 93 relative to its shaft 94, and two outputs 12c, 12d connected by hydraulic conduits not shown on either side of the piston of the cylinder 10 for the displacement of its rod 103 relative to its shaft 104. A main hydraulic pipe 13 supplies the distributor 11 with high pressure hydraulic fluid from a reservoir 14a and a pump 14b.

A low-pressure hydraulic control circuit 15 is provided to control which outlet 12 of the fluid distributor 11 is sent from the supply pipe 13 to the cylinder 9, 10 or received from the cylinder 9, 10. This control circuit 15 is connected to the distributor 11 by a low pressure module 17, which is supplied with fluid by the main pipe 13 via a pressure reducer. In addition, the module 17 is connected to a hydraulic fluid accumulator 16 to ensure a substantially constant low pressure in the circuit 15, for example about 30 bars. The control circuit 15 is connected to a lever 18, which can be moved in different directions relative to a neutral position, to allow a user to control with one hand the different movements of the cylinders 9, 10 via the circuit 15. and the dispenser 11. This lever is for example joystick type or articulated handle, with the types of displacement indicated above.

The circuit 15 thus comprises the following ducts 19 extending between the block 118, with respect to which the lever 18 is movable, and the module 17:

a lifting control conduit 19a connecting an outlet 18a of the lever 18 to a lifting control input 17a of the module 17, to cause the sending of fluid to the outlet 12a and to cause the first cylinder 9 to move when lifting from the stretcher 2 (corresponding to the extension of the cylinder 9 between its ends 91, 92 in the example shown),

a lowering control conduit 19b connecting an outlet 18b of the lever 18 to a lowering control input 17b of the module 17, to cause the sending of fluid on the outlet 12b and to cause the displacement of the first jack 9 in lowering of the stretcher 2 (corresponding to the shortening of the cylinder 9 between its ends 91, 92 in the example shown), - a duct control conduit 19c connected connecting an output 18c of the lever 18 a recess control input 17c of the module 17, to cause the sending of fluid on the output 12c and cause the displacement of the second cylinder 10 in tilt or lifting of the tool holder 6 (corresponding to the shortening of the cylinder 10 between its ends 101, 102 in the example shown),

a discharge control duct 19d connecting an outlet 18d of the lever 18 to a discharge control inlet 17d of the module 17, to cause the sending of fluid to the outlet 12d and to cause the displacement of the second cylinder 10 when the tool holder 6 (corresponding to the elongation of the jack 10 between its ends 101, 102 in the example shown), a conduit 20 for sending low pressure fluid from an outlet 17e of the module 17 to an inlet 18e of the lever 18, with the interposition of a valve 21 normally open during operation,

a conduit 22 for returning fluid from an outlet 18f of the handle 18 to an inlet 17f of the module 17.

A fluid return conduit 23 from the module 17 to the fluid reservoir 14a, as well as a conduit 24 for returning fluid from the distributor 11 to the fluid reservoir 14a, are also provided.

According to the invention, solenoid valves 30a, 30b, 30c, 30d are respectively interposed on the control ducts 19a, 19b, 19c, 19d of the low pressure circuit.

Each solenoid valve 30a, 30b, 30c, 30d comprises:

a first hydraulic access 31a, 31b, 31c, 31d respectively connected to the control output 18a, 18b, 18c, 18d of the joystick 18,

a second hydraulic access 32a, 32b, 32c, 32d respectively connected to the control input 17a, 17b, 17c, 17d of the module 17,

a third hydraulic access 33a, 33b, 33c, 33d connected to the conduit 20 for sending low pressure fluid, a fourth access 34a, 34b, 34c, 34d electrical control of the position of a slide 35a, 35b, 35c , 35d, this fourth access 34a, 34b, 34c, 34d controlling for example a coil for moving the slide valve 35a, 35b, 35c, 35d of the solenoid valve.

The slideway 35a, 35b, 35c, 35d comprises: a first compartment 36a, 36b, 36c, 36d for placing the second hydraulic access 32a, 32b, 32c, 32d in communication with the first hydraulic access 31a, 31b, 31c, 31d ,

a second compartment 37a, 37b, 37c, 37d placing the second hydraulic access 32a, 32b, 32c, 32d in communication with the third hydraulic access 33a, 33b, 33c, 33d. The slide valve 35a, 35b, 35c, 35d of the solenoid valves 30a, 30b, 30c, 30d is adapted to take either a first position, in which it is the first compartment 36a, 36b, 36c, 36d which is in front of the hydraulic accesses 32a. , 32b, 32c, 32d and 31a, 31b, 31c, 31d, for their communication, or a second position, in which it is the second compartment 37a, 37b, 37c, 37d which is in front of the hydraulic accesses 32a , 32b, 32c, 32d and 33a, 33b, 33c, 33d for putting them into communication.

There is provided a sensor 50 indicating the position of the cylinder 10 with respect to a predetermined position in length of the cylinder 10. This predetermined position is intermediate between the first and second positions of the cylinder or equal to one of the first and second positions of the cylinder . This predetermined position corresponds for example to a horizontal position of the tool carried by the tool holder for the jack 10. The jack 10 is a jacking cylinder by shortening the length between its ends 101, 102, in the case where the 10a cylinder has between its ends a length less than the predetermined length corresponding to the predetermined position, the sensor 50 provides a first indication of digging or lifting, while in the case where the cylinder 10 has between its ends a length greater than the length predetermined position corresponding to the predetermined position, the sensor 50 provides a second indication of lowering or dumping.

There is for example a support 51, which is fixed relative to the end 101, on which is mounted the sensor 50 and relative to which a pin 53 driven by the end 102 or the rocker 62 is slidably mounted. The support 51 is for example formed by a tube receiving the pin 53. The sensor is for example a proximity sensor of the pin 51. When the pin 51 is in front of the sensor 50, which corresponds to a crossing of the position predetermined in the direction of tilt, the sensor 50 provides the first indication, whereas when the pin 51 is not in front of the sensor 50, which corresponds to a crossing the predetermined position in the direction of the spill, the sensor 50 provides the second indication.

A similar sensor 150 may be provided on the jack 9, with for example a support 151 and a pin 153 similar to the previous elements. The first lift indication of the sensor 150 corresponds, for this lift cylinder 9 by elongation, to the length greater than the predetermined length and the second indication of the sensor 150 corresponding to the length less than the predetermined length.

In general, the sensor 50 and / or 150 may be provided on a fixed part relative to the cylinder of the associated jack, to detect the presence or absence of a movable bar driven by the rod of this jack.

An automatic control module 70a, for example an electrical module, receives on an input 71a the indication supplied by the sensor 50 and on another input 72a the control or absence state of control generated by an additional manual control member 81 and / or another automatic control module 70b, for example electrical, receives on an input 71b the indication provided by the sensor 150 and on another input 72b the control state or absence of control generated by another additional manual control member 82. There may be provided the first additional manual control member 81 and the sensor 50 associated with the jack 10, and / or the second additional manual control member 82 and the sensor 150 associated with the jack 9. Each member additional 81, 82 manual control is operable in a control state and in a state of absence of control and for example has the form of a push button, whose state d This command corresponds to the pressing of the button and whose state of no control corresponds to the release of the button. For example, the modules 70a, 70b each have the form of a separate electrical box. The modules 70a, 70b can of course be grouped into a single module or electrical box. The handle 18 and the member 81, 82 are provided on or near the dashboard 83 of the vehicle, on the cockpit of the latter comprising a seat for the person driving it, that is to say in the vehicle cab if the latter has one.

The module 70a comprises: an output 73c for controlling the position taken by the solenoid valve 30c, connected to its access 34c,

- A control output 73d of the position taken by the solenoid valve 30d, connected to its access 34d.

The module 70b comprises: an output 73a for controlling the position taken by the solenoid valve 30a, connected to its access 34a,

an output 73b for controlling the position taken by the solenoid valve 30b, connected to its access 34b.

The operation of the control device is as follows. In the presence of a first lifting indication on the input 71a and a control state on the input 72a, the module 70a delivers, by appropriate means on its output 73c, a signal keeping the solenoid valve 30c in its first position. and on its output 73d a first automatic control passing the solenoid valve 30d in its second position. Low pressure fluid is then sent into the conduit 19d from the conduit 20 via the compartment 37d to the lowering control input 17d, thereby causing the displacement of the cylinder 10 in the second direction of lowering or dumping.

In the presence of a second indication of lowering on the input 71a and a control state on the input 72a, the module 70a delivers by appropriate means on its output 73c a second automatic control passing the solenoid valve 30c in its second position and on its output 73d a signal maintaining the solenoid valve 30d in its first position. Low pressure fluid is then sent into the conduit 19c from the conduit 20 via the compartment 37c to the inlet 17c control device, then causing the displacement of the cylinder 10 in the first direction of the digging.

In the case where the member 81 goes into the state of no control, the module 70a passes the solenoid valves 30c and 30d in their first position, to stop the movement of the cylinder 10 in lowering or lifting.

In the presence of a first lifting indication on the input 71b and a control state on the input 72b, the module 70b delivers by a suitable means on its output 73a a signal keeping the solenoid valve 30a in its first position. and on its output 73b a first automatic control passing the solenoid valve 30b in its second position. Low pressure fluid is then sent into the conduit 19b from the conduit 20 via the compartment 37b to the lowering control input 17b, thereby causing the cylinder 9 to move in the second lowering direction.

In the presence of a second indication of lowering on the input 71b and a control state on the input 72b, the module 70b delivers by appropriate means on its output 73a a second automatic control passing the solenoid valve 30a. in its second position and on its output 73b a signal maintaining the solenoid valve 30b in its first position. Low pressure fluid is then sent into the conduit 19a from the conduit 20 via the compartment 37a to the lifting control inlet 17a, thereby causing the displacement of the cylinder 10 in the first direction of lifting. In the case where the member 82 goes to the state of no control, the module 70b passes the solenoid valves 30a and 30b in their first position, to stop the movement of the cylinder 9 in lowering or lifting.

When, the member 81, 82 being in the control state, the sensor 50, 150 passes to the second lowering indication, the first automatic control on the output 73b, 73d and the control accesses 34b, 34d of the solenoid valves 30b, 30d ends, to be replaced by the holding signal in the first position, to stop the movement of the cylinder 9, 10 in lowering.

When, the member 81, 82 being in the control state, the sensor 50, 150 passes to the first hoist indication, the second automatic control to the output 73a, 73c and the control access ports 34a, 34c of the solenoid valves 30a, 30c end, to be replaced by the hold signal in the first position, to stop the movement of the jack 9, 10 lifting. Each additional member 81, 82 thus allows in its control state to move its associated cylinder 10, 9 in one direction or the other.

In their first position, the solenoid valves 30a, 30b, 30c, 30d make it possible to send, by displacement of the handle in the associated direction, low pressure fluid from the respective outlet 18a, 18b, 18c, 18d of the lever via their first compartment. 36a, 36b, 36c, 36d at the corresponding control input 17a, 17b, 17c, 17d of the module 17 to cause the corresponding displacement of the cylinder 9, 10.

The solenoid valves 30a, 30b, 30c, 30d have, for example, a means 38a, 38b, 38c, 38d of stress of the slide 35a, 35b, 35c, 35d in the first position, corresponding to the absence of the automatic control sent to their entry. 34a, 34b, 34c, 34d.

Of course, the means 150, 82, 70b, 30a, 30b associated with the manipulation of the jack 9 and / or the means 50, 81, 70a, 30c, 30d associated with the manipulation of the jack 10 can be provided.

Only one additional control member may be provided to perform the function described above of the additional control members 81, 82. In this case, the state of control or absence of control of this single additional control member is sent to both the input 72a and the input 72b. In FIG. 3, the automatic control module 70a is in the form of an electrical circuit and comprises a type D latch for storing the last indication of the position sensor 50 of the cylinder 10. The indication input 71a is connected at the current state input D of the flip-flop. The next state output Q of the flip-flop is connected via a diode D2 and a resistor R6 to the base of a second transistor Q2. The complemented next state output Q 'of the flip-flop is connected via a diode D4 and a resistor R7 to the base of a first transistor Q5. The transistor Q2 is connected by its emitter to ground and by its collector at one end of a coil of a relay RL1, whose other end is connected to a first end of the drain-source channel of a third transistor Q1. Transistor Q5 is connected by its emitter to ground and by its collector at one end of a coil of a relay RL2, the other end of which is connected to the first end of the drain-source channel of transistor Q1. The transistor Q1 has a state of conduction or non-conduction, controlled by the state of control or lack of control of the member 81 on the input 72a, which is connected to its gate and to the input CLK clock of the flip-flop. The transistor Q1 is connected by the second end of its source drain path to a DC voltage supply terminal V, for example 12 volts. The member 81 is formed by an open contact in the state of absence of control and closed in the control state between two terminals 72a and 72a 'between which a capacitor C1 is connected in parallel. The terminal 72a 'is connected to ground, while the terminal 72a is connected via a resistor R2 to the supply terminal V also serving to supply the sensor 50 with respect to ground. In addition, the node between the resistor R2 and the capacitor C1 is also connected to the clock input CLK of the flip-flop. A rising edge on the clock input CLK of the flip-flop sets its output Q to 0 and its complementary output Q 'to a state

0 on the input D, while a rising edge on the clock input CLK of the flip-flop sets its Q output and 0 its complementary output Q 'for a state

1 on entry D. The node D2-R6 is connected via a diode D1 to the input D of the flip-flop. The node D4-R7 is connected via a diode D5 to the collector of a fourth transistor Q3. The collector of the transistor Q3 is connected to the terminal DC voltage supply via a resistor R4 and its base is connected to the input D of the flip-flop. The flip-flop is powered by terminal V with respect to ground. The base of transistor Q5 is connected to terminal V via a bias resistor R5. The base of the transistor Q2 is connected to the DC voltage supply terminal V via a bias resistor R3. The relay coil RL1 is in parallel with a diode D3. The relay coil RL2 is in parallel with a diode D6. The transistors Q5, Q2, Q3 are of the bipolar NPN type, the transistor Q1 is of the PJFET type and the diodes D3 and D6 are oriented in the opposite direction of conduction of the transistors Q2 and Q5, the diodes D1, D2, D4, D5 are oriented in the conduction direction of the current from the resistors R6, R7.

The operation of this electrical circuit is as follows. For example, assume that the input 71a previously provides a high state 1 corresponding to a first detection indication, the inverse inverse state 0 corresponding to a second detection indication, which creates a corresponding state 1 on the Q output.

In the case where the member 81 moves to the control state, the capacitor C1 is short-circuited, which controls the gate of the transistor Q1 to drive it via its drain-source path. The high state 1 stored on the output Q and the low state 0 stored on the output Q 'polarizes via its base the transistor Q5 in conduction and prevents via its base the conduction of the transistor Q2. A current then flows via the drain-source path of Q1 through the winding of RL2 and the transistor Q5, while this current is prevented from passing into RL1. The winding of RL2 then closes the switch thereof, connected between the DC voltage supply terminal V and the output 73d, which generates the first automatic control on the access 34d and thus the displacement of the cylinder 10 on discharge or lowering. On the other hand, the absence of current in the winding of RL1 keeps its switch open between DC voltage supply terminal V and the output 73c, and thus the maintenance of the output 34c in the first position of absence of automatic control of breakout. In the case where the member 81 goes to the state of absence of control, the capacitor C1 is no longer short-circuited, which blocks the gate of transistor Q1 to prevent it from driving via its drain-source channel . Transistors Q2 and Q5 are then locked in the non-conductive state by transistor Q1. This operation is permuted with respect to transistors

Q2 and Q5 and therefore the outputs 73c and 73d for a low state 0 on the input 71a. Of course, transistors Q2, Q3, Q5 of the PNP type could be provided with the corresponding polarity inversions of the circuit 70a. Likewise, the bipolar type or FET of the transistors can be modified with the corresponding adaptations of the circuit 70a.

The collector-source path of the transistors Q2, Q5 represents their main conduction path, and their base represents their control input of this main conduction path.

The drain-source path of transistor Q1 represents its main conduction path, and its gate represents its control input of this main conduction path.

The module 70b may have an electrical circuit similar to that described above of the module 70a.

Of course the modules 70a, 70b can also be made by digital microprocessor means).

The control device described above can also be used to control the displacement of a third cylinder 90 provided on the tool to move relative to one another two mechanical parts of the tool mounted on the carrier. tool 6, such as for example the upper claws 72 relative to the lower bucket 71 of the tool 7 shown in Figure 1. In FIG. 4, the control device can also be provided for controlling a linkage 100 on a vehicle or tractor 5, this linkage having to carry a tool 200. This lifting can for example be provided at the front or rear of the vehicle 5. Such a lift 100 usually comprises two articulated lateral arms 101, a frame 102 attached to the vehicle 5, the arms 101 being articulated by a side 104 by relative to the frame 102. At the free end of the arms 101, away from the side 104, there are provided members 103 for mounting the tool 200, these members 103 being also called "hands". The control device can be used to control the cylinder (s) 105 for lifting and lowering the arms 101 relative to the frame 102.

In addition, the tool 200 can also be articulated on the arm or arms 101 and be moved relative to these arms 101 by a fifth jack 201. For example, the tool 200 is hinged to the mounting members 103. The control device can be used to control the cylinder or cylinders 201 for moving the tool 200 relative to the arms 101.

Claims

1. Hydraulic control device of at least one cylinder of a machine intended to be installed on a vehicle, the cylinder being operable in a first direction of movement of a first mechanical part of the machine relative to a second mechanical part articulated on the first part and in the second direction opposite the first direction, the device comprising a high pressure hydraulic distributor (11), which is connected to the v erin (9, 10) and which comprises a coupling module (17) to a circuit (15) for low-pressure hydraulic control from a handle (18), the coupling module (17) comprising at least a first actuation control input (17a, 17c) of the cylinder in the first direction by receiving therein of low pressure hydraulic fluid via the low pressure hydraulic control circuit (15) and at least one second actuator control input (17b, 17d) in the second direction by receiving therein e low pressure hydraulic fluid via the low pressure hydraulic control circuit (15), the lever comprising at least a first output (18a, 18c) of low pressure hydraulic fluid, able to be activated by moving the lever in a first prescribed direction corresponding for sending low pressure hydraulic fluid to the first inlet (17a, 17c), and at least a second output (18b, 18d) of low pressure hydraulic fluid, adapted to be activated by movement of the handle in a corresponding second prescribed direction for sending hydraulic fluid to the second inlet (17b , 17d), characterized in that the control device further comprises: at least one sensor (50, 150) of the cylinder (9, 10), able to provide a first detection indication when the cylinder has passed a predetermined position in the first direction and a second indication of detection when said jack has passed said predetermined position in the second direction, an additional member (81, 82) for manual control, operable either in a control state, or in a state of absence of control, a module ( 70a, 70b), connected to the cylinder position sensor (50, 150) and to the additional manual control member (81, 82), and able to generate in the presence of the control state and the first detection indication a first automatic control on a first access (34b, 34d), and in the presence of the control state and the second detection indication a second automatic control on a second access (34a, 34c), a first means (30a, 30c) for hydraulic switching of the first hydraulic control input (17a, 17c) or on a conduit (20) for automatic low pressure fluid delivery in the presence of the second automatic control on the second port ( 34a, 34c), or on the first output (18a, 18c) of hydraulic fluid in the absence of the second automatic control on the second access (34a, 34c), a second means (30b, 30d) of hydraulic switching of the second input ( 17b, 17d), either on the conduit (20) for automatic low pressure fluid delivery in the presence of the first automatic control on the first access (34b, 34d), or on the second output (18b, 18d) hydraulic fluid in the absence of the first automatic control on the first access (34b, 34d). 2. Hydraulic control device according to claim 1, characterized in that the additional manual control member is formed by a push button, whose control state corresponds to pressing the button and whose state of no control corresponds to the release of the button. 3. Hydraulic control device according to claim 2, characterized in that the push button is provided on the handle. 4. Hydraulic control device according to any one of the preceding claims, characterized in that the automatic control module (70a, 70b) is electric and comprises electrical inputs (71a, 72a, 71b, 72b) for receiving power. state of the additional body (81, 82) for manual control and indication of the sensor (50, 150), the hydraulic switching means (30a, 30b, 30c, 30d) are formed by solenoid valves of which said electrical accesses (34a, 34b, 34c, 34d) are connected to electrical outputs (73a, 73b, 73c, 73d) for controlling the position of the solenoid valves. 5. Hydraulic control device according to any one of the preceding claims, characterized in that the sensor (50, 150) of the cylinder position (9, 10) is fixed on a support (51, 151) fixed relative to the barrel of the cylinder and is a proximity sensor of a part (53, 153) driven by the rod of the cylinder, movable relative to the support (51, 151) and located in front of the sensor from said predetermined position in the one of the first and second senses and not in front of the sensor otherwise. Hydraulic control device according to one of the preceding claims, characterized in that the automatic control module (70a, 70b) comprises a D-type latch for storing the last indication of the position sensor (50, 150). the cylinder (9, 10). Hydraulic control device according to Claim 6, characterized in that the automatic control module (70a, 70b) comprises: a first transistor (Q5) for generating, by its main conduction path, the first automatic control or its absence on a first control output (73d) of the first access (34d), as a function of the signal present on an input control device, connected to the next state output (Q ') complementary to the flip-flop, a second transistor (Q2) for generating, by its main conduction path, the second automatic control or its absence on a second control output (73c) of the second access (34c), as a function of the signal present on a channel control input, connected to the next state output (Q) of the flip-flop, a third transistor (Q1), the main conduction path of which is arranged to allow, in the event of conduction, powering the main conduction path of the first and second transistors, and whose channel control input is connected to an electrical input (72a) for receiving the status of the additional manual control member (81, 82) for controlling the conduction of the main channel of the third transistor for the control state of the additional unit (81, 82) for manual control and non-conduction of the main channel of the third transistor for the state of absence of control of the additional manual control member (81, 82), means (R6, R7, D2, D4) being provided on the control inputs and on the outputs (Q, Q ') of the state of the flip-flop for these flip-flop outputs to select by their next state and their next state complementary conduction of the main channel of the first or second transistor (Q5) with the non-conduction of the main channel of the second or first transistor (Q5) in case of conduction of the main channel of the third transistor (Q1). 8. Application of the hydraulic control device according to any one of claims 1 to 7 to a loader, the loader comprising a frame for attachment to the vehicle, a stretcher rotatable relative to the frame, a tool holder rotatable relative to the stretcher, at least a first hydraulic cylinder for moving the stretcher relative to the frame in the first direction of lifting or in the second opposite direction of lowering, and at least a second hydraulic cylinder for moving the tool holder by relative to the stretcher in the first direction of lifting or in the second opposite direction of lowering, characterized in that the control device is applied to the first jack (9). 9. Application of the hydraulic control device according to any one of claims 1 to 7 to a loader, the loader comprising a frame for attachment to the vehicle, a stretcher rotatable relative to the frame, a tool holder rotatable relative to the stretcher, at least a first hydraulic cylinder for moving the stretcher relative to the frame in the first direction of lifting or in the second opposite direction of lowering, and at least a second hydraulic cylinder for moving the tool holder by relative to the stretcher in the first direction of lifting or in the second opposite direction of lowering, characterized in that the control device is applied to the second cylinder (10). 10. Application of the hydraulic control device according to any one of claims 1 to 7 to a machine having at least a first cylinder and at least a second cylinder, the first cylinder being operable in a first direction of movement of a first part mechanical mechanism of the machine relative to a second mechanical part articulated on the first part and in the second direction opposite to the first direction, the second actuator being operable in a first direction of movement of a third mechanical part of the machine relative to the second mechanical part and in the second opposite direction to the first direction, characterized in that the control device is applied to the first cylinder (9) and the second cylinder (10). 11. Application according to claim 10, characterized in that a single additional manual control member (81, 82) is provided for controlling the automatic control module (70b) associated with the first jack (9) and for controlling the module (70a) automatic control associated with the second cylinder (10). 12. Application of the hydraulic control device according to any one of claims 1 to 7 to a loader, the loader comprising a frame for attachment to the vehicle, a stretcher rotatable relative to the frame, a tool holder rotatable relative to the stretcher, a tool, which is mounted on the tool holder and which comprises a second movable part articulated on a first part of the tool, at least a first hydraulic cylinder for moving the stretcher relative to the frame in the first direction of lifting or in the second opposite direction of lowering, at least one second hydraulic cylinder for moving the tool holder relative to the stretcher in the first direction of lifting or in the second opposite direction of lowering, and on the tool at least a third hydraulic cylinder for moving the second part of the tool relative to its first part, characterized in that the control device is applied to u third cylinder (90). 13. Application of the hydraulic control device according to any one of claims 1 to 7 to a lift for carrying a tool, the lift comprising at least one lifting arm articulated relative to a frame intended to be fixed to the vehicle, and at least one cylinder for moving the arm relative to the frame in the first direction of lifting or in the second opposite direction of lowering, characterized in that the control device is applied to said cylinder (105). 14. Application of the hydraulic control device according to any one of claims 1 to 7 to a lift, the lift comprising at least one lifting arm articulated relative to a frame intended to be fixed to the vehicle, at least one hydraulic cylinder of moving the arm relative to the frame in the first direction of lifting or in the second opposite direction of lowering, a rotary tool on the arm and at least a second hydraulic cylinder for moving in the first direction of lifting or in the second opposite direction of lowering, characterized in that the control device is applied to the second cylinder (201).