EP0147256B1 - Continuous and intermittent feed of hydraulic fluid to a ram - Google Patents

Continuous and intermittent feed of hydraulic fluid to a ram Download PDF

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Publication number
EP0147256B1
EP0147256B1 EP84402194A EP84402194A EP0147256B1 EP 0147256 B1 EP0147256 B1 EP 0147256B1 EP 84402194 A EP84402194 A EP 84402194A EP 84402194 A EP84402194 A EP 84402194A EP 0147256 B1 EP0147256 B1 EP 0147256B1
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EP
European Patent Office
Prior art keywords
pipe
pressure
accumulator
hydraulic
jack
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP84402194A
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German (de)
French (fr)
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EP0147256A1 (en
Inventor
Jean-Pierre Augoyard
Philippe Guggemos
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GTM Entrepose SA
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GTM Entrepose SA
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Priority to AT84402194T priority Critical patent/ATE31786T1/en
Publication of EP0147256A1 publication Critical patent/EP0147256A1/en
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Publication of EP0147256B1 publication Critical patent/EP0147256B1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/12—Fluid oscillators or pulse generators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators

Definitions

  • the present invention relates to a method for supplying hydraulic fluid, continuously and by controlled impulse, with accumulation of hydraulic energy, a hydraulic cylinder normally working continuously, and it also relates to a device for implementing this method.
  • Hydraulic cylinders working continuously and their hydraulic fluid supply system are well known. They are usually used to move a load or tool in a continuous movement over a distance which can be relatively large. Whether working on push or pull, a cylinder pressure chamber is supplied with pressurized hydraulic fluid to move the piston of the cylinder over part or all of its stroke in a continuous movement at a speed which depends on the supply pressure and the resistant force encountered by the piston rod of the jack. The return of the piston rod to its starting position is ensured either by means of a spring (single-acting cylinder), or by supplying pressurized fluid to the other chamber of the hydraulic cylinder (double-acting cylinder).
  • the amplitude and the frequency can be adjusted to adapt them to the nature of the materials to be extracted (according to this previous document, a high frequency is advantageous with fine-grained materials, while a lower frequency is preferable with coarse-grained materials) .
  • this known system behaves like a continuously oscillating system, the oscillations of which are systematic, whether or not the shovel 1 encounters an increase in resistance during its movement.
  • the control device 10 is simply intended to replace the operator when the latter can no longer obtain a sufficiently high desired frequency of oscillation by actuating only the hand lever back and forth. 8.
  • it facilitates the penetration of the shovel into the material to be extracted, such a principle of operation is nevertheless unfavorable insofar as the mechanical parts are subject to rapid wear due to their reciprocating or oscillating movement. high frequency.
  • the present invention aims to solve this problem.
  • the method of the present invention is characterized in that it consists in supplying a pressure chamber of the hydraulic cylinder with hydraulic fluid and, simultaneously, in storing hydraulic energy in an accumulator from from a source of pressurized fluid, as long as the pressure in the pressure chamber of the cylinder remains below a selected value, so that the cylinder normally works continuously, to isolate the pressure chamber of the hydraulic cylinder from the source of pressurized fluid when the pressure in the pressure chamber of the jack reaches said chosen value, at connect the pressure chamber of the jack to a hydraulic fluid reservoir to drop the pressure in said pressure chamber, then isolate the pressure chamber of the jack from the reservoir, then put the accumulator in communication only with the chamber pressure of the jack to send a pulse of hydraulic fluid thereto, and then isolating the pressure chamber of the jack from the accumulator and re-establishing the connection between the source of pressurized fluid, on the one hand, and the pressure chamber and the accumulator, on the other hand, and to maintain them in this being as long as the pressure in the
  • the supply device for implementing this method comprises, in a known manner, a pump, a fluid reservoir, a first pipe having a first end and a second end which can be connected to a pressure chamber of a jack. hydraulic, a main distributor connected to the pump, to the reservoir and the first end of the first piping to put the latter in selective communication with the pump or with the reservoir, and a hydraulic energy accumulator.
  • the supply device is characterized in that it further comprises a first piloted valve which is connected to the first pipe and to the tank and which, in a rest position, isolates the first pipe from the tank and, in a position of work, establishes communication between the first piping and the tank, a second piloted valve which is inserted in the first piping between the second end thereof and the first piloted valve and which, in a rest position, allows the passage of the fluid in the first pipe and, in a working position, cuts the said passage, a second pipe having a first and a second end connected to the first pipe respectively between the main distributor and the second piloted valve and between the latter and the second end of the first piping, said accumulator being connected to the second piping, valve means inserted in the second piping ie and comprising a third piloted valve which, in a rest position, prevents the passage of the fluid in the second piping from accumulator towards the second end of the second piping and, in a working position, authorizes the passage of fluid from
  • the feeding device shown in fig. 1 comprises in known manner, a pump 1, a reservoir 2 of hydraulic fluid, a main distributor 3 and two pipes 4 and 5 connected respectively to the two pressure chambers 6 and 7 of the cylinder of a double-acting cylinder 8 (only one two pipes 4 and 5 would be provided in the case of a single-acting cylinder).
  • the main distributor 3 is shown in a neutral position, in which the fluid sucked by the pump 1 in the tank 2 is returned again to the tank.
  • the main distributor 3 When the main distributor 3 is placed in one or other of its two working positions, the fluid sucked by the pump 1 is discharged through the piping 4 to the chamber 6 or through the piping 5 to the chamber 7 , depending on the working position of the main distributor, that of the two chambers 6 and 7 which is not supplied with pressurized fluid being connected through the piping 4 or 5 to the tank.
  • the supply device of the present invention further comprises a hydraulic block 9 which, in the case envisaged above, is inserted in the piping 4 between the main distributor 3 and the chamber 6 of the jack 8.
  • the hydraulic block 9 comprises a first pilo valve tee 10, which is inserted into the pipe 4 and which, in its rest position shown in FIG. 1, lets the hydraulic fluid pass through the piping 4 and, in its working position, establishes a communication between the piping 4 and the tank 2.
  • the hydraulic block 9 comprises a second piloted valve 11 which is also inserted in the piping 4 , between the piloted valve 10 and the chamber 6 of the jack 8, and which, in its rest position shown in FIG. 1, authorizes the passage of the fluid in the pipe 4 and, in its working position, cuts said passage.
  • the hydraulic unit 9 further comprises a pipe 12, one end of which is connected to the pipe 4 between the main distributor 3 and the second piloted valve 11, for example between the main distributor 3 and the first piloted valve 10 as shown in fig. 1, and the other end of which is connected to the pipe 4 between the second piloted valve 11 and the chamber 6 of the jack 8.
  • a pipe 12 In the pipe 12 are inserted in series, from the first end to the second end of the pipe 12, a unidirectional valve 13, an accumulator 14 and a third piloted valve 15.
  • the unidirectional valve 13 is connected so as to allow the passage of the hydraulic fluid only from the main distributor 3 towards the accumulator 14. In its rest position shown on the fig.
  • the piloted valve 15 cuts the passage of the fluid in the piping 12, while in its working position, it allows the passage of the fluid from the accumulator 14 to the chamber 6 of the jack 8.
  • an adjustable nozzle 16 can be inserted into the piping 12 downstream of the piloted valve 15 to adjust the flow rate of the hydraulic fluid towards the chamber 6 of the jack 8 when the piloted valve 15 is in its working position.
  • the piloted valves 10, 11 and 15 can be actuated by a sequential control unit 17, which will now be described with reference to FIG. 4.
  • the three piloted valves 10, 11 and 15 are electro-valves that can be actuated by the excitation coils or solenoids Sa, Sb and Sc, respectively.
  • the number 18 designates a current supply source, for example a 12 V or 24 V battery
  • the number 19 designates a circuit breaker which, when it is energized, connects two supply conductors 20 and 21 respectively across the current source 18.
  • the sequential control unit 17 comprises a first relay Re having a normally open contact R, a second and a third relay, M l and M 2 both having a contact, respectively M lT and M 2T , normally open and delayed on closing, and a fourth relay M 3 having a contact M 3T normally closed and delayed on opening.
  • the duration of the delay of the third relay M 2 is slightly longer than that of the second relay M, as will be seen below.
  • a first end of the excitation coils Re, M i , M 2 , M 3 , Sa, Sb and Sc is connected to the supply conductor 20.
  • the other end of the excitation coils Re, M i , M 2 , Sa and Sb, the latter through the normally open contact M 1T , is connected to the supply conductor 21, on the one hand, through one or the other of two normally open contacts BP and PR connected in parallel and , on the other hand, through the normally open contact R and the normally closed contact M 3T connected in series.
  • the other end of the excitation coils M 3 and Sc is connected to the junction point 22 between the normally open contact R and the normally closed contact M 3T through the normally open contact M 2T .
  • the BP contact remains a push button contact. It allows manual control of the start of an operating sequence of the solenoid valves 10, 11 and 15, provided that the pressure in the chamber 6 of the jack 8 and in the accumulator 14 has reached a sufficient value, which can be checked by means of one or other of the two manometers 23 and 24 connected to the pipes 4 and 12, respectively (fig. 1).
  • the PR contact is the contact of a pressure switch 25, which makes it possible to automatically control the start of an operating sequence of the solenoid valves 10, 11 and 15 each time the pressure in the chamber 6 of the jack 8 and in the accumulator 14 reaches the triggering threshold of the pressure switch 25.
  • the triggering threshold of the pressure switch 25 can for example be adjusted to the maximum pressure that can be supplied by the pump 1, or to a value slightly lower than the maximum pressure.
  • the pressure switch 25 is hydraulically connected to the pipe 4 between the main distributor 3 and the solenoid valve 11.
  • the triggering threshold of the pressure switch 25 is adjusted to a pressure of 300 bars, and that the accumulator 14 is a membrane accumulator, inflated with nitrogen at a pressure 100 bars (of course, other types of accumulator can be used, for example accumulators in which the active element, membrane or piston, is prestressed by a calibrated spring). Under these conditions, when the solenoid valves 10, 11 and 15 are in their rest position shown in FIG.
  • the normally open contact PR closes, which is represented by the high state in FIG. 5 (in this figure, the closed state of the contacts and the energized state of the coils is represented by the high state, while the open state of the contacts and the de-energized state of the coils is represented by the low state) .
  • the closing of the contact PR causes the excitation of the relay Re which closes its contact R, and also the excitation of the relays M 1 and M 2 and of the coil Sa of the solenoid valve 10.
  • the relay M 3 and the coils Sb and Sc of the solenoid valves 11 and 15 are not energized since the contacts M 1T and M 2T of the relays M 1 and M 2 are delayed upon closing.
  • the contact M 2T closes, which has the effect of exciting the relay M 3 and the coil Sc of the solenoid valve 15.
  • the latter is then switched to its working position and, consequently, the accumulator 14 is connected to the chamber 6 of the jack 8 and sends a pulse of hydraulic fluid to the latter.
  • the length of the piping 12 and of the piping 4 between the accumulator 14 and the jack 8 is as short as possible so that the hydraulic fluid pulse is transmitted to the chamber 6 in the shortest possible time.
  • the contact M 3T opens, which has the effect of de-energizing all the relays Re, M i , M 2 and M 3 , and the coils Sa, Sb, Sc of the solenoid valves 10, 11 and 15. As a result, the sequential control unit 17 is reset.
  • each operating sequence of the solenoid valves 10, 11 and 15 is automatically started by the pressure switch 25.
  • the push button BP by pressing one or more times on the BP push button, the operator can manually start one or more sequences of operation of the solenoid valves when he notices that a strong resistance is opposed to the displacement of the piston rod 27 or when he finds that the pressure read on either of the pressure gauges 23 and 24 to exceed the pressure of inflation of the nitrogen in the accumulator 14 (100 bars in the example considered here).
  • curve A in solid lines represents the variation over time of the pressure of the hydraulic fluid in the accumulator 14, while curve B in dashed lines represents the variation over time of the pressure in the chamber 6 of the jack 8 during a typical example of operation.
  • curve B in dashed lines represents the variation over time of the pressure in the chamber 6 of the jack 8 during a typical example of operation.
  • the lower horizontal line H l represents the pressure of inflation of the nitrogen in the accumulator 14
  • the upper horizontal line H 2 represents the maximum pressure that can be supplied by the pump 1 and also the triggering threshold of the pressure switch 25, and the area between the two lines H 1 and H 2 represents the working range of the accumulator 14.
  • valves 30 and 31 are provided for selectively placing the accumulator 14 or the accumulator 29 in communication with the piping 12, while the valves 32 and 33 are provided to put the unused accumulator 14 or 29 in communication with the tank 2.
  • the time delays of the relays M i , M 2 and M 3 can be adjusted for example by means of adjustment buttons 34, 35 and 36, respectively, accessible on one face of the casing of the sequential control unit 17 (fig. 1).
  • the piloted valve 10 is inserted in the piping 4.
  • the piloted valve 10 can be inserted in a piping 37 connected in bypass to the piping 4 as shown in FIG. 2. In this case, the operation would be exactly the same as that described above.
  • the present invention finds application in many fields of technology. Examples include metalworking (presses for spinning, drawing, stamping, stamping) and soil and rock working (hydraulic shovels working in backhoe or loader, civil or agricultural engineering tractor working in ripping , etc.) and, in general, in all cases where a hydraulic cylinder normally working continuously must be able to provide a momentary dynamic force, at any point of its stroke, to overcome an increase in resistance during movement of its piston rod.
  • FIG. 7 a hydraulic shovel 42 comprising, in a known manner, an arrow 43, which is pivotally mounted at its rear end on the chassis and which can be actuated by a jack 45, a pendulum 46, which is pivotally mounted at its rear end on the 'front end of the boom 43 and which can be actuated by a jack 47, and a bucket 48, provided with knockout teeth 49, which is pivotally mounted in retro at the front end of the pendulum 46 and which can be actuated by a jack such as the jack 8 of FIG. 1, by means of a lifter 50 and a link 51.
  • a hydraulic shovel 42 comprising, in a known manner, an arrow 43, which is pivotally mounted at its rear end on the chassis and which can be actuated by a jack 45, a pendulum 46, which is pivotally mounted at its rear end on the 'front end of the boom 43 and which can be actuated by a jack 47, and a bucket 48, provided with knockout teeth
  • the jack 8 is carried by the pendulum 46 on which are also arranged the hydraulic block 9 and the accumulator 14 of FIG. 1.
  • the front part of the hydraulic shovel 42 of FIG. 7 with a pendulum 46 fitted with a bucket '48 mounted as a loader.
  • the unidirectional valve 13 (fig. 1) can be replaced by a piloted valve identical to the piloted valve 11 and which, in a rest position, authorizes the passage of the hydraulic fluid through the piping 12 to the accumulator 14 or 29 and, in a working position, cuts said passage.
  • the sequential control unit 17 must actuate the piloted valve 13 at the same time as the piloted valve 10.
  • the sequential control unit 17 can be produced in the form of electronic circuits with transistors or integrated circuits.
  • the sequential control unit 17 may itself be constituted by switches and delay circuits operating with compressed air or with a hydraulic fluid under pressure.
  • the jack 8 works mainly in the thrust. If it works mainly in traction, it is enough to connect the piping 5 to the chamber 6 and the piping 4 to the chamber 7.
  • jack 8 works as well in the thrust as in the traction and if hydraulic impulses must being able to be sent both to chamber 6 and to chamber 7, it suffices to insert into the piping 5 a second hydraulic block identical to the hydraulic block 9 of FIG. 1 or, more simply, to have a reversing valve in the pipes 4 and 5 between the hydraulic block 9 and the jack 8.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Operation Control Of Excavators (AREA)
  • Lifting Devices For Agricultural Implements (AREA)
  • Actuator (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Reciprocating Pumps (AREA)
  • Refuse Collection And Transfer (AREA)
  • Portable Nailing Machines And Staplers (AREA)
  • Press Drives And Press Lines (AREA)

Abstract

A method of supplying a normally continuous operating hydraulic actuator with hydraulic fluid, continuously and by controlled pulse, comprising the steps of supplying a chamber of an actuator and, simultaneously, storing an hydraulic energy in an accumulator from a pressurized fluid source, as long as the pressure in the chamber remains less than a chosen value, isolating the accumulator from the source when the pressure in the chamber reaches a chosen value, connecting the chamber to a reservoir, then isolating the chamber from the reservoir, then causing the accumulator to communicate with the chamber, isolating the chamber from the accumulator and re-establishing the communication between the source, on the one hand, and the chamber and the accumulator, on the other, and maintaining them in this state as long as the pressure in the chamber does not again reach said chosen value.

Description

La présente invention concerne un procédé pour alimenter en fluide hydraulique, en continu et par impulsion contrôlée, avec accumulation d'énergie hydraulique, un vérin hydraulique travaillant normalement en continu, et elle concerne également un dispositif pour la mise en oeuvre de ce procédé.The present invention relates to a method for supplying hydraulic fluid, continuously and by controlled impulse, with accumulation of hydraulic energy, a hydraulic cylinder normally working continuously, and it also relates to a device for implementing this method.

Les vérins hydrauliques travaillant en continu et leur système d'alimentation en fluide hydraulique sont bien connus. Ils sont habituellement utilisés pour déplacer une charge ou un outil en un mouvement continu sur une distance qui peut être relativement importante. Qu'ils travaillent à la poussée ou à la traction, une chambre de pression du vérin est alimentée en fluide hydraulique sous pression pour déplacer le piston du vérin sur une partie ou la totalité de sa course en un mouvement continu à une vitesse qui dépend de la pression d'alimentation et de l'effort résistant rencontré par la tige de piston du vérin. Le retour de la tige de piston à sa position de départ est assuré soit au moyen d'un ressort (vérin à simple effet), soit en alimentant en fluide sous pression l'autre chambre du vérin hydraulique (vérin à double effet).Hydraulic cylinders working continuously and their hydraulic fluid supply system are well known. They are usually used to move a load or tool in a continuous movement over a distance which can be relatively large. Whether working on push or pull, a cylinder pressure chamber is supplied with pressurized hydraulic fluid to move the piston of the cylinder over part or all of its stroke in a continuous movement at a speed which depends on the supply pressure and the resistant force encountered by the piston rod of the jack. The return of the piston rod to its starting position is ensured either by means of a spring (single-acting cylinder), or by supplying pressurized fluid to the other chamber of the hydraulic cylinder (double-acting cylinder).

On connaît par ailleurs (FR-A-2243357) des systèmes d'alimentation en fluide hydraulique à accumulation d'énérgie pour des appareils hydrauliques travaillant en alternatif, par exemple des marteaux piqueurs ou des brise-roche hydrauliques, dans lesquels le piston du vérin agit sur un outil comme un marteau à mouvement altérnatif. Dans ce cas, le système d'alimentation émet toujours et à chaque course du piston une seule impulsion hydraulique à énergie constante. Chaque impulsion hydraulique déplace le piston sur la totalité de sa course. Du fait de leur aspect répétitif, on peut dire que ces systèmes connus s'apparentent à des vibreurs. Leur emploi ne peut porter que sur des vérins de faible course (de l'ordre de 10 cm).There are also known (FR-A-2243357) hydraulic fluid supply systems with energy accumulation for hydraulic devices working alternately, for example jackhammers or hydraulic breakers, in which the piston of the jack acts on a tool like a hammer with alternating movement. In this case, the supply system always emits a single constant energy hydraulic pulse at each stroke of the piston. Each hydraulic pulse moves the piston over its entire stroke. Because of their repetitive appearance, it can be said that these known systems are similar to vibrators. They can only be used on short stroke cylinders (of the order of 10 cm).

L'impulsion hydraulique étant systématique, il n'est pas tenu compte, de ce fait, de la résistance effective rencontrée au déplacement du piston du vérin, et on ne cherche pas à moduler la quantité et la valeur d'une énergie hydraulique d'appoint en fonction des paramètres d'utilisation.The hydraulic impulse being systematic, it is not taken into account, therefore, the effective resistance encountered to the displacement of the piston of the jack, and no attempt is made to modulate the quantity and the value of a hydraulic energy of topping up according to the usage parameters.

On connaît par ailleurs (DE-C-886121) une pelle hydraulique pour le creusement, le ramassage ou l'enlèvement de matières à extraire, dans laquelle, pour communiquer à la pelle 1 un mouvement rapide de va-et-vient, le vérin hydraulique à double effet 2 qui actionne la pelle peut être alimenté alternativement et de manière périodique en fluide hydraulique. Ceci est obtenu au moyen d'un organe de commande 9 (probablement un distributeur de fluide hydraulique, bien qu'il ne soit pas décrit en détail), qui peut être lui-même actionné soit manuellement au moyen d'un levier de manoeuvre 8, soit automatiquement au moyen d'un dispositif de commande 10 animé d'un mouvement d'oscillation, lorsqu'une haute fréquence est nécessaire et ne peut plus être obtenue manuellement par utilisation du levier 8. Il est prévu que l'amplitude et la fréquence peuvent être réglées pour les adapter à la nature des matières à extraire (d'après ce document antérieur, une haute fréquence est avantageuse avec des matières à grains fins, tandis qu'une fréquence plus basse est préférable avec des matières à gros grains). Ainsi, lorsque le dispositif de commande 10 est actif, ce système connu se comporte comme un système oscillant en permanence, dont les oscillations sont systématiques, que la pelle 1 rencontre ou non un accroissement de résistance au cours de son mouvement. En fait, le dispositif de commande 10 est simplement destiné à remplacer l'opérateur lorsque celui-ci ne peut plus obtenir une fréquence d'oscillation désirée suffisamment élevée en actionnant seulement à la main, en va-et-vient, le levier de manoeuvre 8. Bien qu'il facilite la pénétration de la pelle dans les matières à extraire, un tel principe de fonctionnement est néanmoins défavorable dans la mesure où les pièces mécaniques sont sujettes à une usure rapide à cause de leur mouvement alternatif ou d'oscillation à haute fréquence.Also known (DE-C-886121) a hydraulic shovel for digging, collecting or removing material to be extracted, in which, to communicate to the shovel 1 a rapid back and forth movement, the jack double acting hydraulic 2 which operates the shovel can be supplied alternately and periodically with hydraulic fluid. This is obtained by means of a control member 9 (probably a hydraulic fluid distributor, although it is not described in detail), which can itself be actuated either manually by means of an operating lever 8 , or automatically by means of a control device 10 animated by an oscillating movement, when a high frequency is necessary and can no longer be obtained manually by using lever 8. It is intended that the amplitude and the frequency can be adjusted to adapt them to the nature of the materials to be extracted (according to this previous document, a high frequency is advantageous with fine-grained materials, while a lower frequency is preferable with coarse-grained materials) . Thus, when the control device 10 is active, this known system behaves like a continuously oscillating system, the oscillations of which are systematic, whether or not the shovel 1 encounters an increase in resistance during its movement. In fact, the control device 10 is simply intended to replace the operator when the latter can no longer obtain a sufficiently high desired frequency of oscillation by actuating only the hand lever back and forth. 8. Although it facilitates the penetration of the shovel into the material to be extracted, such a principle of operation is nevertheless unfavorable insofar as the mechanical parts are subject to rapid wear due to their reciprocating or oscillating movement. high frequency.

Dans de nombreux domaines de la technique, il arrive que la tige de piston d'un vérin hydraulique travaillant normalement en continu rencontre un accroissement de résistance dans une position donnée de sa course ou, occasionnellement, dans une position quelconque de sa course. On peut, bien entendu, dimensionner la pompe et les circuits hydrauliques du dispositif d'alimentation de telle façon que celui-ci soit capable de fournir au vérin une pression hydraulique suffisante pour vaincre un tel accroissement de résistance. Toutefois, cela oblige à surdimensionner le dispositif d'alimentation par rapport aux besoins courants. De toutes façons, si l'accroissement de résistance est tel que la pression dans le vérin devient supérieure à la pression maximale que peut fournir la pompe, le vérin ne peut plus travailler.In many fields of technology, it can happen that the piston rod of a hydraulic cylinder normally working continuously encounters an increase in resistance in a given position of its stroke or, occasionally, in any position of its stroke. It is, of course, possible to size the pump and the hydraulic circuits of the supply device in such a way that it is capable of supplying the jack with sufficient hydraulic pressure to overcome such an increase in resistance. However, this requires oversizing the supply device in relation to current needs. In any case, if the increase in resistance is such that the pressure in the cylinder becomes greater than the maximum pressure that the pump can provide, the cylinder can no longer work.

Il serait donc utile de fournir un dispositif d'alimentation tel qu'un vérin travaillant normalement en continu soit capable de produire un effort dynamique momentané, dans une position quelconque de sa course, pour surmonter un accroissement de résistance au cours de déplacement de sa tige de piston, sans qu'il soit nécessaire à cet effet de surdimensionner le dispositif d'alimentation.It would therefore be useful to provide a supply device such that a cylinder normally working continuously is capable of producing a momentary dynamic force, in any position of its stroke, to overcome an increase in resistance during displacement of its rod. piston, without it being necessary for this purpose to oversize the supply device.

La présente invention a pour but de résoudre ce problème.The present invention aims to solve this problem.

A cet effet, le procédé de la présente invention est caractérisé en ce qu'il consiste à alimenter une chambre de pression du vérin hydraulique en fluide hydrauliqué et, simultanément, à emmaga siner de l'énergie hydraulique dans un accumula-, teur à partir d'une source de fluide sous pression, tant que la pression dans la chambre de pression du vérin reste inférieure à une valeur choisie, de telle façon que le vérin travaille normalement en continu, à isoler la chambre de pression du vérin hydraulique par rapport à la source de fluide sous pression quand la pression dans la chambre de pression du vérin atteint ladite valeur choisie, à relier la chambre de pression du vérin à un réservoir de fluide hydraulique pour faire chuter la pression dans ladite chambre de pression, à isoler ensuite la chambre de pression du vérin par rapport au réservoir, à mettre ensuite l'accumulateur en communication seulement avec la chambre de pression du vérin pour y envoyer une impulsion de fluide hydraulique, et, ensuite, à isoler la chambre de pression du vérin par rapport à l'accumulateur et à rétablir la liaison entre la source de fluide sous pression, d'une part, et la chambre de pression et l'accumulateur, d'autre part, et à les maintenir dans cet étant tant que la pression dans la chambre de pression n'atteint pas à nouveau ladite valeur choisie.To this end, the method of the present invention is characterized in that it consists in supplying a pressure chamber of the hydraulic cylinder with hydraulic fluid and, simultaneously, in storing hydraulic energy in an accumulator from from a source of pressurized fluid, as long as the pressure in the pressure chamber of the cylinder remains below a selected value, so that the cylinder normally works continuously, to isolate the pressure chamber of the hydraulic cylinder from the source of pressurized fluid when the pressure in the pressure chamber of the jack reaches said chosen value, at connect the pressure chamber of the jack to a hydraulic fluid reservoir to drop the pressure in said pressure chamber, then isolate the pressure chamber of the jack from the reservoir, then put the accumulator in communication only with the chamber pressure of the jack to send a pulse of hydraulic fluid thereto, and then isolating the pressure chamber of the jack from the accumulator and re-establishing the connection between the source of pressurized fluid, on the one hand, and the pressure chamber and the accumulator, on the other hand, and to maintain them in this being as long as the pressure in the pressure chamber does not again reach said chosen value.

Le dispositif d'alimentation pour la mise en oeuvre de ce procédé comprend, de façon connue, une pompe, un réservoir de fluide, une première tuyauterie ayant une première extrémité et une seconde extrémité pouvant être reliée à une chambre de pression d'un vérin hydraulique, un distributeur principal relié à la pompe, au réservoir et la première extrémité de la première tuyauterie pour mettre cette dernière en communication sélectivement avec la pompe ou avec le réservoir, et un accumulateur d'énergie hydraulique. Le dispositif d'alimentation est caractérisé en ce qu'il comprend en outre une première valve pilotée qui est reliée à la première tuyauterie et au réservoir et qui, dans une position de repos, isole la première tuyauterie du réservoir et, dans une position de travail, établit une communication entre la première tuyauterie et le réservoir, une deuxième valve pilotée qui est insérée dans la première tuyauterie entre la seconde extrémité de celle-ci et la première valve pilotée et qui, dans une position de repos, autorise le passage du fluide dans la première tuyauterie et, dans une position de travail, coupe ledit passage, une deuxième tuyauterie ayant une première et une deuxième extrémité raccordées à la première tuyauterie respectivement entre le distributeur principal et la deuxième valve pilotée et entre cette dernière et la deuxième extrémité de la première tuyauterie, ledit accumulateur étant connecté à la deuxième tuyauterie, des moyens à valves insérés dans la deuxième tuyauterie et comportant une troisième valve pilotée qui, dans une position de repos, interdit le passage du fluide dans la deuxième tuyauterie depuis d'accumulateur vers la seconde extrémité de la deuxième tuyauterie et, dans une position de travail, autorise le passage de fluide depuis le premier accumulateur vers la deuxième extrémité des deuxième et première tuyauteries, et un dispositif de commande comportant un moyen sensible à la pression, qui est connecté du point de vue hydraulique à la première tuyauterie pour donner une indication de la valeur de la pression hydraulique régnant dans cette première tuyauterie, ledit dispositif de commande étant relié aux première, deuxième et troisième valves pilotées et étant agencé, lorsque le moyen sensible à la pression indique que la pression hydraulique dans la première tuyauterie a atteint une valeur choisie, pour actionner successivement, dans l'ordre, la première, la deuxième et la troisième valve pilotée dans leur position de travail et pour les ramener ensuite dans leur position de repos.The supply device for implementing this method comprises, in a known manner, a pump, a fluid reservoir, a first pipe having a first end and a second end which can be connected to a pressure chamber of a jack. hydraulic, a main distributor connected to the pump, to the reservoir and the first end of the first piping to put the latter in selective communication with the pump or with the reservoir, and a hydraulic energy accumulator. The supply device is characterized in that it further comprises a first piloted valve which is connected to the first pipe and to the tank and which, in a rest position, isolates the first pipe from the tank and, in a position of work, establishes communication between the first piping and the tank, a second piloted valve which is inserted in the first piping between the second end thereof and the first piloted valve and which, in a rest position, allows the passage of the fluid in the first pipe and, in a working position, cuts the said passage, a second pipe having a first and a second end connected to the first pipe respectively between the main distributor and the second piloted valve and between the latter and the second end of the first piping, said accumulator being connected to the second piping, valve means inserted in the second piping ie and comprising a third piloted valve which, in a rest position, prevents the passage of the fluid in the second piping from accumulator towards the second end of the second piping and, in a working position, authorizes the passage of fluid from the first accumulator towards the second end of the second and first piping, and a control device comprising pressure-sensitive means, which is hydraulically connected to the first piping to give an indication of the value of the prevailing hydraulic pressure in this first piping, said control device being connected to the first, second and third piloted valves and being arranged, when the pressure-sensitive means indicates that the hydraulic pressure in the first piping has reached a chosen value, to actuate successively, in the order, the first, the second and the third valve piloted in their working position and for r then return them to their rest position.

D'autres caractéristiques et les avantages de la présente invention ressortiront au cours de la description qui va suivre d'une forme d'exécution du dispositif d'alimentation de la présente invention, donnée en référence aux dessins annexés sur lesquels:

  • La fig. 1 montre schématiquement les circuits hydrauliques du dispositif d'alimentation conforme à la présente invention;
  • la fig. 2 montre une variante de branchement de l'une des valves pilotées du dispositif d'alimentation de la fig. 1;
  • la fig. 3 montre une variante de branchement d'une autre valve pilotée du dispositif d'alimentation de la fig. 1;
  • la fig. 4 représente le schéma de l'unité de commande séquentielle associée au dispositif d'alimentation de la fig. 1;
  • la fig. 5 est un diagramme illustrant le fonctionnement de l'unité de commande séquentielle de la fig. 4;
  • la fig. 6 est un diagramme temps/pression, montrant comment la pression dans le vérin et la pression dans l'accumulateur du dispositif d'alimentation de la fig. 1 évoluent en cours de fonctionnement avec le dispositif d'alimentation de la présente invention;
  • la fig. 7 représente, schématiquement, une pelle hydraulique, équipée d'un godet travaillant en rétro, et dans laquelle est incorporé le dispositif d'alimentation de la présente invention;
  • la fig. 8 est une vue partielle de la pelle hydrau- lique de la fig. 7, équipée d'un godet travaillant en butte ou en chargeur.
Other characteristics and advantages of the present invention will emerge during the following description of an embodiment of the supply device of the present invention, given with reference to the appended drawings in which:
  • Fig. 1 schematically shows the hydraulic circuits of the supply device according to the present invention;
  • fig. 2 shows a variant of connection of one of the controlled valves of the supply device of FIG. 1;
  • fig. 3 shows a variant of connection of another valve controlled by the supply device of FIG. 1;
  • fig. 4 shows the diagram of the sequential control unit associated with the supply device of FIG. 1;
  • fig. 5 is a diagram illustrating the operation of the sequential control unit of FIG. 4;
  • fig. 6 is a time / pressure diagram showing how the pressure in the cylinder and the pressure in the accumulator of the supply device of FIG. 1 evolve during operation with the power supply device of the present invention;
  • fig. 7 shows, schematically, a hydraulic shovel, equipped with a bucket working in reverse, and in which is incorporated the feed device of the present invention;
  • fig. 8 is a partial view of the shovel hydrau - lic of FIG. 7, equipped with a bucket working in hillock or loader.

Le dispositif d'alimentation représenté sur la fig. 1 comprend de façon connue, une pompe 1, un réservoir 2 de fluide hydraulique, un distributeur principal 3 et deux tuyauteries 4 et 5 raccordées respectivement aux deux chambres de pression 6 et 7 du cylindre d'un vérin à double effet 8 (une seule des deux tuyauteries 4 et 5 serait prévue dans le cas d'un vérin à simple effet). Dans la fig. 1, le distributeur principal 3 est représenté dans une position neutre, dans laquelle le fluide aspiré par la pompe 1 dans le réservoir 2 est refoulé à nouveau vers le réservoir. Quand le distributeur principal 3 est placé dans l'une ou l'autre de ses deux positions de travail, le fluide aspiré par la pompe 1 est refoulé à travers la tuyauterie 4 vers la chambre 6 ou à travers la tuyauterie 5 vers la chambre 7, selon la position de travail du distributeur principal, celle des deux chambres 6 et 7 qui n'est pas alimentée en fluide sous pression étant reliée à travers la tuyauterie 4 ou 5 au réservoir.The feeding device shown in fig. 1 comprises in known manner, a pump 1, a reservoir 2 of hydraulic fluid, a main distributor 3 and two pipes 4 and 5 connected respectively to the two pressure chambers 6 and 7 of the cylinder of a double-acting cylinder 8 (only one two pipes 4 and 5 would be provided in the case of a single-acting cylinder). In fig. 1, the main distributor 3 is shown in a neutral position, in which the fluid sucked by the pump 1 in the tank 2 is returned again to the tank. When the main distributor 3 is placed in one or other of its two working positions, the fluid sucked by the pump 1 is discharged through the piping 4 to the chamber 6 or through the piping 5 to the chamber 7 , depending on the working position of the main distributor, that of the two chambers 6 and 7 which is not supplied with pressurized fluid being connected through the piping 4 or 5 to the tank.

Dans la suite du présente texte, on supposera que le vérin hydraulique 8 est destiné à travailler à la poussée. Le dispositif d'alimentation de la présente invention comprend en outre un bloc hydraulique 9 qui, dans le cas envisagé ci-dessus, est inséré dans la tuyauterie 4 entre le distributeur principal 3 et la chambre 6 du vérin 8. Le bloc hydraulique 9 comprend une première valve pilotée 10, qui est insérée dans la tuyauterie 4 et qui, dans sa position de repos montrée sur la fig. 1, laisse passer le fluide hydraulique à travers la tuyauterie 4 et, dans sa position de travail, établit une communication entre la tuyauterie 4 et le réservoir 2. Le bloc hydraulique 9 comporte une deuxième valve pilotée 11 qui est aussi insérée dans la tuyauterie 4, entre la valve pilotée 10 et la chambre 6 du vérin 8, et qui, dans sa position de repos montrée sur la fig. 1, autorise le passage du fluide dans la tuyauterie 4 et, dans sa position de travail, coupe ledit passage.In the remainder of this text, it will be assumed that the hydraulic cylinder 8 is intended to work on the thrust. The supply device of the present invention further comprises a hydraulic block 9 which, in the case envisaged above, is inserted in the piping 4 between the main distributor 3 and the chamber 6 of the jack 8. The hydraulic block 9 comprises a first pilo valve tee 10, which is inserted into the pipe 4 and which, in its rest position shown in FIG. 1, lets the hydraulic fluid pass through the piping 4 and, in its working position, establishes a communication between the piping 4 and the tank 2. The hydraulic block 9 comprises a second piloted valve 11 which is also inserted in the piping 4 , between the piloted valve 10 and the chamber 6 of the jack 8, and which, in its rest position shown in FIG. 1, authorizes the passage of the fluid in the pipe 4 and, in its working position, cuts said passage.

Le bloc hydraulique 9 comporte en outre une tuyauterie 12, dont l'une des extrémités est raccordée à la tuyauterie 4 entre le distributeur principal 3 et la deuxième valve pilotée 11, par exemple entre le distributeur principal 3 et la première valve pilotée 10 comme montré sur la fig. 1, et dont l'autre extrémité est raccordée à la tuyauterie 4 entre la seconde valve pilotée 11 et la chambre 6 du vérin 8. Dans la tuyauterie 12 sont insérés en série, depuis la première extrémité vers la deuxième extrémité de la tuyauterie 12, une valve unidirectionnelle 13, un accumulateur 14 et une troisième valve pilotée 15. La valve unidirectionnelle 13 est branchée de manière à permettre le passage du fluide hydraulique uniquement depuis le distributeur principal 3 vers l'accumulateur 14. Dans sa position de repos montrée sur la fig. 1, la valve pilotée 15 coupe le passage du fluide dans la tuyauterie 12, tandis que dans sa position de travail, elle autorise le passage du fluide depuis l'accumulateur 14 vers la chambre 6 du vérin 8. Comme montré dans la fig. 1, un ajutage réglable 16 peut être inséré dans la tuyauterie 12 en aval de la valve pilotée 15 pour régler le débit du fluide hydraulique vers la chambre 6 du vérin 8 quand la valve pilotée 15 est dans sa position de travail.The hydraulic unit 9 further comprises a pipe 12, one end of which is connected to the pipe 4 between the main distributor 3 and the second piloted valve 11, for example between the main distributor 3 and the first piloted valve 10 as shown in fig. 1, and the other end of which is connected to the pipe 4 between the second piloted valve 11 and the chamber 6 of the jack 8. In the pipe 12 are inserted in series, from the first end to the second end of the pipe 12, a unidirectional valve 13, an accumulator 14 and a third piloted valve 15. The unidirectional valve 13 is connected so as to allow the passage of the hydraulic fluid only from the main distributor 3 towards the accumulator 14. In its rest position shown on the fig. 1, the piloted valve 15 cuts the passage of the fluid in the piping 12, while in its working position, it allows the passage of the fluid from the accumulator 14 to the chamber 6 of the jack 8. As shown in FIG. 1, an adjustable nozzle 16 can be inserted into the piping 12 downstream of the piloted valve 15 to adjust the flow rate of the hydraulic fluid towards the chamber 6 of the jack 8 when the piloted valve 15 is in its working position.

Les valves pilotées 10, 11 et 15 peuvent être actionnées par une unité de commande séquentielle 17, qui va maintenant être décrite en faisant référence à la fig. 4. Dans la suite du présent texte, on supposera que les trois valves pilotées 10,11 et 15 sont des électro-valves pouvant être actionnées par les bobines d'excitation ou solénoïdes Sa, Sb et Sc, respectivement. Dans la fig. 4, le numéro 18 désigne une source d'alimentation en courant, par exemple une batterie de 12 V ou 24 V, et le numéro 19 désigne un disjoncteur qui, lorsqu'il est enclenché, relie deux conducteurs d'alimentation 20 et 21 respectivement aux bornes de la source de courant 18. L'unité de commande séquentielle 17 comprend un premier relais Re ayant un contact R normalement ouvert, un deuxième et un troisième relais, Ml et M2 ayant tous les deux un contact, respectivement MlT et M2T, normalement ouvert et temporisé à la fermeture, et un quatrième relais M3 ayant un contact M3T normalement fermé et temporisé à l'ouverture. La durée de la temporisation du troisième relais M2 est légèrement plus grande que celle du deuxième relais M, comme on le verra plus loin. Une première extrémité des bobines d'excitation Re, Mi, M2, M3, Sa, Sb et Sc est connectée au conducteur d'alimentation 20. L'autre extrémité des bobines d'excitation Re, Mi, M2, Sa et Sb, cette dernière à travers le contact normalement ouvert M1T, est connectée au conducteur d'alimentation 21, d'une part, à travers l'un ou l'autre de deux contacts normalement ouverts BP et PR connectés en parallèle et, d'autre part, à travers le contact normalement ouvert R et le contact normalement fermé M3T connectés en série. L'autre extrémité des bobines d'excitation M3 et Sc est connectée au point de jonction 22 entre le contact normalement ouvert R et le contact normalement fermé M3T à travers le contact normalement ouvert M2T.The piloted valves 10, 11 and 15 can be actuated by a sequential control unit 17, which will now be described with reference to FIG. 4. In the rest of this text, it will be assumed that the three piloted valves 10, 11 and 15 are electro-valves that can be actuated by the excitation coils or solenoids Sa, Sb and Sc, respectively. In fig. 4, the number 18 designates a current supply source, for example a 12 V or 24 V battery, and the number 19 designates a circuit breaker which, when it is energized, connects two supply conductors 20 and 21 respectively across the current source 18. The sequential control unit 17 comprises a first relay Re having a normally open contact R, a second and a third relay, M l and M 2 both having a contact, respectively M lT and M 2T , normally open and delayed on closing, and a fourth relay M 3 having a contact M 3T normally closed and delayed on opening. The duration of the delay of the third relay M 2 is slightly longer than that of the second relay M, as will be seen below. A first end of the excitation coils Re, M i , M 2 , M 3 , Sa, Sb and Sc is connected to the supply conductor 20. The other end of the excitation coils Re, M i , M 2 , Sa and Sb, the latter through the normally open contact M 1T , is connected to the supply conductor 21, on the one hand, through one or the other of two normally open contacts BP and PR connected in parallel and , on the other hand, through the normally open contact R and the normally closed contact M 3T connected in series. The other end of the excitation coils M 3 and Sc is connected to the junction point 22 between the normally open contact R and the normally closed contact M 3T through the normally open contact M 2T .

Le contact BP rest un contact à bouton poussoir. Il permet de commander manuellement le démarrage d'une séquence de fonctionnement des électro-valves 10, 11 et 15, sous réserve que la pression dans la chambre 6 du vérin 8 et dans l'accumulateur 14 a atteint une valeur suffisante, ce qui peut être contrôlé au moyen de l'un ou l'autre des deux manomètres 23 et 24 reliés aux tuyauteries 4 et 12, respectivement (fig. 1). Le contact PR est le contact d'un pressostat 25, qui permet de commander automatiquement le démarrage d'une séquence de fonctionnement des électro-valves 10, 11 et 15 chaque fois que la pression dans la chambre 6 du vérin 8 et dans l'accumulateur 14 atteint le seuil de déclenchement du pressostat 25. Le seuil de déclenchement du pressostat 25 peut être par exemple réglé à la pression maximale que peut fournir la pompe 1, ou à une valeur légèrement inférieure à la pression maximale. Le pressostat 25 est relié, du point de vue hydraulique, à la tuyauterie 4 entre le distributeur principal 3 et l'électrovalve 11.The BP contact remains a push button contact. It allows manual control of the start of an operating sequence of the solenoid valves 10, 11 and 15, provided that the pressure in the chamber 6 of the jack 8 and in the accumulator 14 has reached a sufficient value, which can be checked by means of one or other of the two manometers 23 and 24 connected to the pipes 4 and 12, respectively (fig. 1). The PR contact is the contact of a pressure switch 25, which makes it possible to automatically control the start of an operating sequence of the solenoid valves 10, 11 and 15 each time the pressure in the chamber 6 of the jack 8 and in the accumulator 14 reaches the triggering threshold of the pressure switch 25. The triggering threshold of the pressure switch 25 can for example be adjusted to the maximum pressure that can be supplied by the pump 1, or to a value slightly lower than the maximum pressure. The pressure switch 25 is hydraulically connected to the pipe 4 between the main distributor 3 and the solenoid valve 11.

Bien entendu, si on désire commander uniquement manuellement ou uniquement automatiquement le démarrage d'une séquence de fonctionnement des électro-valves 10, 11 et 15, l'un ou l'autre des deux contacts BP et PR peut être omis selon le cas.Of course, if it is desired to control only manually or only automatically the start of an operating sequence of the solenoid valves 10, 11 and 15, one or the other of the two contacts BP and PR can be omitted as the case may be.

On décrira maintenant le fonctionnement du dispositif d'alimentation de la présente invention en faisant référence aux fig. 1,4 et 5. Pour fixer les idées, on supposera que le seuil de déclenchement du pressostat 25 est réglé à une pression de 300 bars, et que l'accumulateur 14 est un accumulateur à membrane, gonflé à l'azote à une pression de 100 bars (bien entendu, d'autres types d'accumulateur sont utilisables, par exemple des accumulateurs dans lesquels l'élément actif, membrane ou piston, est précontraint par un ressort taré). Dans ces conditions, lorsque les électro-valves 10, 11 et 15 sont dans leur position de repos montrée sur la fig. 1 et lorsque le distributeur principal 3 est dans une position telle que la chambre 6 du vérin est alimentée en fluide sous pression à travers la tuyauterie 4 et à travers les électro-valves 10 et 11, le piston 26 du vérin 8 et sa tige du piston 27 sont déplacés vers l'extérieur en un mouvement continu. Si la tige de piston 27 rencontre une résistance importante à un moment quelconque au cours de son déplacement, la pression du fluide s'élève dans la chambre 6 du vérin et dans la tuyauterie 4. Dès que la pression dépasse 100 bars, l'accumulateur 14 commence à se charger à travers la valve unidirectionnelle 13 et à emmagasiner de l'énergie par le déplacement de sa membrane. Si, du fait de l'augmentation de la pression, le vérin réussit à vaincre la résistance qui lui est opposée, le système se remet alors à fonctionner normalement. Par contre, si le vérin n'arrive pas à vaincre la résistance qui lui est opposée, la pression dans la chambre 6 et dans la tuyauterie 4 continue à augmenter et l'accumulateur 14 continue à emmagasiner de l'énergie jusqu'à ce que la pression atteigne le seuil de déclenchement du pressostat 25, par exemple 300 bars. A ce moment, le contact normalement ouvert PR se ferme, ce qui est représenté par l'état haut dans la fig. 5 (dans cette figure, l'état fermé des contacts et l'état excité des bobines est représenté par l'état haut, tandis que l'état ouvert des contacts et l'état désexcité des bobines est représenté par l'état bas). La fermeture du contact PR provoque l'excitation du relais Re qui ferme son contact R, et aussi l'excitation des relais M1 et M2 et de la bobine Sa de l'électrovalve 10. Toutefois, à ce moment, le relais M3 et les bobines Sb et Sc des électro-valves 11 et 15 ne sont pas excités puisque les contacts M1T et M2T des relais M1 et M2 sont temporisés à la fermeture.The operation of the supply device of the present invention will now be described with reference to FIGS. 1,4 and 5. To fix the ideas, it will be assumed that the triggering threshold of the pressure switch 25 is adjusted to a pressure of 300 bars, and that the accumulator 14 is a membrane accumulator, inflated with nitrogen at a pressure 100 bars (of course, other types of accumulator can be used, for example accumulators in which the active element, membrane or piston, is prestressed by a calibrated spring). Under these conditions, when the solenoid valves 10, 11 and 15 are in their rest position shown in FIG. 1 and when the main distributor 3 is in a position such that the chamber 6 of the jack is supplied with pressurized fluid through the piping 4 and through the solenoid valves 10 and 11, the piston 26 of the jack 8 and its rod piston 27 are moved outward in a continuous movement. If the piston rod 27 encounters significant resistance at any time during its movement, the fluid pressure rises in the chamber 6 of the cylinder and in the piping 4. As soon as the pressure drops passes 100 bars, the accumulator 14 begins to charge through the one-way valve 13 and to store energy by the displacement of its membrane. If, due to the increase in pressure, the cylinder succeeds in overcoming the resistance opposed to it, the system then resumes functioning normally. On the other hand, if the jack fails to overcome the resistance which is opposed to it, the pressure in the chamber 6 and in the piping 4 continues to increase and the accumulator 14 continues to store energy until the pressure reaches the triggering threshold of the pressure switch 25, for example 300 bars. At this moment, the normally open contact PR closes, which is represented by the high state in FIG. 5 (in this figure, the closed state of the contacts and the energized state of the coils is represented by the high state, while the open state of the contacts and the de-energized state of the coils is represented by the low state) . The closing of the contact PR causes the excitation of the relay Re which closes its contact R, and also the excitation of the relays M 1 and M 2 and of the coil Sa of the solenoid valve 10. However, at this time, the relay M 3 and the coils Sb and Sc of the solenoid valves 11 and 15 are not energized since the contacts M 1T and M 2T of the relays M 1 and M 2 are delayed upon closing.

L'excitation de la bobine Sa fait passer l'électro-valve 10 dans sa position de travail. Il en résulte que la tuyauterie 4 est maintenant reliée au reservoir 2. Par suite, la pression dans la tuyauterie 4 et dans la chambre 6 du vérin chute rapidement à zéro, la valve unidirectionnelle 13 se ferme et le contact PR du pressostat 25 s'ouvre à nouveau. L'ouverture du contact PR n'a aucun effet puisque, à ce moment, le contact R est fermé et maintient l'excitation des relais Re, M1 et M2 et de la bobine Sa.The excitation of the coil Sa causes the electro-valve 10 to pass into its working position. As a result, the pipe 4 is now connected to the reservoir 2. As a result, the pressure in the pipe 4 and in the chamber 6 of the jack drops rapidly to zero, the one-way valve 13 closes and the contact PR of the pressure switch 25 s open again. Opening the PR contact has no effect since, at this time, the R contact is closed and keeps the relays Re, M 1 and M 2 and the Sa coil energized.

Au bout d'un temps t1 (fig. 5), par exemple de 0,5 s, correspondant à la temporisation du relais Mi, le contact M1T se ferme, ce qui a pour effet exciter la bobine Sb de l'électro-valve 11 qui est alors commutée dans sa position de travail. Il en résulte que la chambre 6 du vérin 8 cesse d'être reliée au réservoir.After a time t 1 (fig. 5), for example 0.5 s, corresponding to the time delay of the relay M i , the contact M 1T closes, which has the effect of exciting the coil Sb of the solenoid valve 11 which is then switched to its working position. As a result, the chamber 6 of the cylinder 8 ceases to be connected to the reservoir.

Au bout d'un temps t2 (fig. 5) qui correspond à la temporisation du relais M2 et qui est légèrement plus grand que le temps t1, par exemple 0,7 s, le contact M2T se ferme, ce qui a pour effet d'exciter le relais M3 et la bobine Sc de l'électro-valve 15. Cette dernière est alors commutée dans sa position de travail et, par suite, l'accumulateur 14 est relié à la chambre 6 du vérin 8 et envoie à ce dernier une impulsion de fluide hydraulique. De préférence, la longueur de la tuyauterie 12 et de la tuyauterie 4 entre l'accumulateur 14 et le vérin 8 est la plus courte possible pour que l'impulsion de fluide hydraulique soit transmise à la chambre 6 dans le temps le faible possible. Comme l'impulsion hydraulique est envoyée dans un bref intervalle de temps dans la chambre 6 du vérin 8, il en résulte que le piston 26 reçoit un choc hydraulique de forte puissance qui contribue à vaincre la résistance opposée au déplacement de la tige de piston 27. On notera que, pendant que la tuyauterie 4 et la chambre 6 étaient reliées au réservoir 2, le piston 26 du vérin 8 avait légèrement reculé par suite de la résistance opposée au déplacement de la tige de piston 27. Il en résulte que, lorsque l'impulsion hydraulique est envoyée dans la chambre 6, le piston 26 est à nouveau déplacé vers l'extérieur et son énergie cinétique s'ajoute à l'énergie du choc hydraulique pour vaincre la résistance opposée au déplacement de la tige de piston 27. Afin de profiter encore plus de l'énergie cinétique du piston 26 pendant la durée du choc hydraulique, il est aussi possible de faire reculer encore plus le piston 26 pendant que la chambre 6 et la tuyauterie 4 sont reliées au réservoir à travers l'électro-valve 10 et avant que l'impulsion hydraulique soit envoyée à la chambre 6 à travers l'électro-valve 15. Ceci peut être par exemple obtenu en alimentant momentanément la chambre 7 du vérin 8 en fluide sous pression à l'aide d'une électro-valve supplémentaire convenablement disposée entre la pompe 1 et la tuyauterie 5.After a time t 2 (fig. 5) which corresponds to the time delay of the relay M 2 and which is slightly larger than the time t 1 , for example 0.7 s, the contact M 2T closes, which has the effect of exciting the relay M 3 and the coil Sc of the solenoid valve 15. The latter is then switched to its working position and, consequently, the accumulator 14 is connected to the chamber 6 of the jack 8 and sends a pulse of hydraulic fluid to the latter. Preferably, the length of the piping 12 and of the piping 4 between the accumulator 14 and the jack 8 is as short as possible so that the hydraulic fluid pulse is transmitted to the chamber 6 in the shortest possible time. As the hydraulic impulse is sent in a short time interval in the chamber 6 of the cylinder 8, it follows that the piston 26 receives a high-power hydraulic shock which contributes to overcoming the resistance opposed to the displacement of the piston rod 27 It will be noted that, while the piping 4 and the chamber 6 were connected to the tank 2, the piston 26 of the jack 8 had slightly retreated as a result of the resistance opposed to the displacement of the piston rod 27. It follows that, when the hydraulic impulse is sent into the chamber 6, the piston 26 is again displaced towards the outside and its kinetic energy is added to the energy of the hydraulic shock to overcome the resistance opposed to the displacement of the piston rod 27. In order to benefit even more from the kinetic energy of the piston 26 during the duration of the hydraulic shock, it is also possible to make the piston 26 move further back while the chamber 6 and the piping 4 are connected to the working tank. ers the electro-valve 10 and before the hydraulic impulse is sent to the chamber 6 through the electro-valve 15. This can for example be obtained by temporarily supplying the chamber 7 of the jack 8 with pressurized fluid at l using an additional solenoid valve suitably placed between the pump 1 and the piping 5.

Au bout du temps t3 (fig. 5), par exemple de 0,5s, correspondant à la temporisation du relais M3, le contact M3T s'ouvre, ce qui a pour effet de désexciter tous les relais Re, Mi, M2 et M3, et les bobines Sa, Sb, Sc des électro-valves 10, 11 et 15. Il en résulte que, l'unité de commande séquentielle 17 est remise à l'état initial.At the end of time t 3 (fig. 5), for example 0.5s, corresponding to the time delay of the relay M 3 , the contact M 3T opens, which has the effect of de-energizing all the relays Re, M i , M 2 and M 3 , and the coils Sa, Sb, Sc of the solenoid valves 10, 11 and 15. As a result, the sequential control unit 17 is reset.

Si la résistance qui s'opposait au déplacement de la tige de piston 27 du vérin 8 a été vaincue, la pression dans la chambre 6 du vérin retombe et la tige de piston reprend son mouvement continu jusqu'à ce qu'elle rencontre à nouveau une forte résistance. Par contre, si la résistance qui s'opposait au déplacement de la tige de piston 27 n'a pas été vaincue par le premier choc hydraulique appliqué au piston 26, la pression dans la chambre 6 du vérin s'élève à nouveau rapidement et, simultanément, l'accumulateur 14 emmagasine à nouveau de l'énergie, jusqu'à ce que la pression atteigne le seuil de déclenchement du pressostat 25 (300 bars), provoquant ainsi une deuxième séquence de fonctionnement des électro-valves 10, 11 et 15 et, par suite, un second choc hydraulique sur le piston 26 du vérin. La séquence de fonctionnement des électro-valves 10, 11 et 15 se répète ainsi et une succession de chocs hydrauliques sont appliquées au piston 26 du vérin tant que la résistance qui s'oppose au déplacement de sa tige du piston 27 n'a pas été vaincue, après quoi la tige de piston 27 reprend son mouvement continu jusqu'à ce qu'elle rencontre à nouveau une forte résistance.If the resistance opposing the displacement of the piston rod 27 of the cylinder 8 has been overcome, the pressure in the chamber 6 of the cylinder drops and the piston rod resumes its continuous movement until it meets again strong resistance. On the other hand, if the resistance which opposed the displacement of the piston rod 27 was not overcome by the first hydraulic shock applied to the piston 26, the pressure in the chamber 6 of the jack rises again quickly and, simultaneously, the accumulator 14 stores energy again, until the pressure reaches the triggering threshold of the pressure switch 25 (300 bars), thus causing a second sequence of operation of the solenoid valves 10, 11 and 15 and, consequently, a second hydraulic shock on the piston 26 of the jack. The operating sequence of the solenoid valves 10, 11 and 15 is thus repeated and a succession of hydraulic shocks are applied to the piston 26 of the jack as long as the resistance which opposes the movement of its piston rod 27 has not been defeated, after which the piston rod 27 resumes its continuous movement until it again encounters strong resistance.

Dans ce qui précède, on a supposé que chaque séquence de fonctionnement des électro-valves 10, 11 et 15 est démarrée automatiquement par le pressostat 25. Toutefois, dans le cas où le bouton poussoir BP est prévu, en appuyant une ou plusieurs fois sur le bouton poussoir BP, l'opérateur peut démarrer manuellement une ou plusieurs séquences de fonctionnement des électro-valves lorsqu'il constate qu'une forte résistance s'oppose au déplacement de la tige de piston 27 ou lorsqu'il constate que la pression lue sur l'un ou l'autre des manomètres 23 et 24 a dépasser la pression de gonflage de l'azote dans l'accumulateur 14 (100 bars dans l'exemple considéré ici).In the foregoing, it has been assumed that each operating sequence of the solenoid valves 10, 11 and 15 is automatically started by the pressure switch 25. However, in the case where the push button BP is provided, by pressing one or more times on the BP push button, the operator can manually start one or more sequences of operation of the solenoid valves when he notices that a strong resistance is opposed to the displacement of the piston rod 27 or when he finds that the pressure read on either of the pressure gauges 23 and 24 to exceed the pressure of inflation of the nitrogen in the accumulator 14 (100 bars in the example considered here).

Dans le graphique de la fig. 6, la courbe A en trait plein représente la variation dans le temps de la pression du fluide hydraulique dans l'accumulateur 14, tandis que la courbe B en trait mixte représente la variation dans le temps de la pression dans la chambre 6 du vérin 8 au cours d'un exemple typique de fonctionnement. Dans la partie gauche du graphique de la fig. 6, on a représenté le cas où un seul choc hydraulique C suffit pour vaincre la résistance qui s'oppose au déplacement de la tige de piston 27, tandis que dans la partie médiane du même graphique on a représenté le cas où trois chocs hydrauliques successifs Cl, C2 et C3 sont nécessaires pour vaincre la résistance qui s'oppose au déplacement de la tige de piston 27. Dans le graphique de la fig. 6, la ligne horizontale inférieure Hl représente la pression de, gonflage de l'azote dans l'accumulateur 14, la ligne horizontale supérieure H2 représente la pression maximale que peut fournir la pompe 1 et aussi le seuil de déclenchement du pressostat 25, et la zone entre les deux lignes H1 et H2 représente la plage de travail de l'accumulateur 14. Si on désire travailler dans une plage plus large ou plus étroite que celle représentée sur la fig. 6, on peut bien entendu régler la pression de gonflage de l'azote dans l'accumulateur 14. Toutefois, il est plus rationnel d'utiliser un ou plusieurs autres accumulateurs, comme l'accumulateur 29 montré dans la fig. 1, le ou les autres accumulateurs additionnels ayant une membrane qui est précontrainte à une pression différente de celle de la membrane de l'accumulateur 14. Dans ce cas, des robinets 30 et 31 sont prévus pour mettre sélectivement l'accumulateur 14 ou l'accumulateur 29 en communication avec la tuyauterie 12, tandis que les robinets 32 et 33 sont prévus pour mettre l'accumulateur non-utilisé 14 ou 29 en communication avec le réservoir 2.In the graph in fig. 6, curve A in solid lines represents the variation over time of the pressure of the hydraulic fluid in the accumulator 14, while curve B in dashed lines represents the variation over time of the pressure in the chamber 6 of the jack 8 during a typical example of operation. On the left side of the graph in fig. 6, the case where a single hydraulic shock C is sufficient to overcome the resistance which opposes the displacement of the piston rod 27, while the middle part of the same graph shows the case where three successive hydraulic shocks C l , C 2 and C 3 are necessary to overcome the resistance which opposes the displacement of the piston rod 27. In the graph of fig. 6, the lower horizontal line H l represents the pressure of inflation of the nitrogen in the accumulator 14, the upper horizontal line H 2 represents the maximum pressure that can be supplied by the pump 1 and also the triggering threshold of the pressure switch 25, and the area between the two lines H 1 and H 2 represents the working range of the accumulator 14. If it is desired to work in a wider or narrower range than that shown in FIG. 6, it is of course possible to adjust the inflation pressure of the nitrogen in the accumulator 14. However, it is more rational to use one or more other accumulators, such as the accumulator 29 shown in FIG. 1, the other additional accumulator (s) having a membrane which is prestressed at a pressure different from that of the membrane of the accumulator 14. In this case, valves 30 and 31 are provided for selectively placing the accumulator 14 or the accumulator 29 in communication with the piping 12, while the valves 32 and 33 are provided to put the unused accumulator 14 or 29 in communication with the tank 2.

Si on le désire, les temporisations des relais Mi, M2 et M3 peuvent être réglées par exemple au moyen de boutons de réglage 34,35 et 36, respectivement, accessibles sur une face du boîtier de l'unité séquentielle de commande 17 (fig. 1).If desired, the time delays of the relays M i , M 2 and M 3 can be adjusted for example by means of adjustment buttons 34, 35 and 36, respectively, accessible on one face of the casing of the sequential control unit 17 (fig. 1).

Dans la forme d'excécution du bloc hydraulique 9 représenté sur la fig. 1, on a supposé que la valve pilotée 10 était insérée dans la tuyauterie 4. Toutefois, la valve pilotée 10 peut être insérée dans une tuyauterie 37 branchée en dérivation sur la tuyauterie 4 comme montré sur la fig. 2. Dans ce cas, le fonctionnement serait exactement le même que celui-qui a été décrit plus haut.In the embodiment of the hydraulic block 9 shown in FIG. 1, it has been assumed that the piloted valve 10 is inserted in the piping 4. However, the piloted valve 10 can be inserted in a piping 37 connected in bypass to the piping 4 as shown in FIG. 2. In this case, the operation would be exactly the same as that described above.

En outre, dans le bloc hydraulique 9 représenté sur la fig. 1, lorsque la valve pilotée 11 est dans sa position de repos, le fluide hydraulique circule de gauche à droite à travers cette valve lorsque la chambre 6 du vérin est normalement alimentée en fluide sous pression (valve pilotée 10 dans sa position de repos), tandis que le fluide hydraulique circule de droite à gauche à travers la valve pilotée 11 lorsque la chambre 6 est reliée au réservoir 2 à travers la valve pilotée 10 dans sa position de travail. Avec certains modèles de valves pilotées, il est souhaitable que le fluide hydraulique circule toujours dans le même sens à travers la valve pilotée. Dans ce cas, la valve pilotée 11 peut être branchée, du point de vue hydraulique, comme montré sur la fig. 3. Plus précisément, quatre valves unidirectionnelles 38, 39, 40 et 41, montées en pont de Wheatstone, sont insérées dans la tuyauterie 4, celle-ci étant reliée aux extrémités d'une diagonale du pont, la valve pilotée 11 étant montée dans l'autre diagonale du pont. Dans ces conditions, lorsque la chambre 6 du vérin 8 est alimentée en fluide sous pression, le fluide circule successivement à travers la partie supérieure de la tuyauterie 4, la valve unidirectionnelle 38, la valve pilotée 11, la valve unidirectionnelle 39 et la partie inférieure de la tuyauterie 4. Par contre, quand la chambre 6 du vérin 8 est reliée au réservoir 2, le fluide hydraulique circule successivement à travers la partie inférieure de la tuyauterie 4, la valve unidirectionnelle 40, la valve pilotée 11, la valve unidirectionnelle 41 et la partie supérieure de la tuyauterie 4. Dans les deux cas, le fluide hydraulique traverse donc la valve pilotée 11 dans le même sens.In addition, in the hydraulic block 9 shown in FIG. 1, when the piloted valve 11 is in its rest position, the hydraulic fluid flows from left to right through this valve when the chamber 6 of the jack is normally supplied with pressurized fluid (piloted valve 10 in its rest position), while the hydraulic fluid flows from right to left through the piloted valve 11 when the chamber 6 is connected to the reservoir 2 through the piloted valve 10 in its working position. With certain models of piloted valves, it is desirable that the hydraulic fluid always circulates in the same direction through the piloted valve. In this case, the piloted valve 11 can be connected, from the hydraulic point of view, as shown in FIG. 3. More specifically, four unidirectional valves 38, 39, 40 and 41, mounted in a Wheatstone bridge, are inserted into the pipe 4, the latter being connected to the ends of a diagonal of the bridge, the piloted valve 11 being mounted in the other diagonal of the bridge. Under these conditions, when the chamber 6 of the jack 8 is supplied with pressurized fluid, the fluid flows successively through the upper part of the piping 4, the unidirectional valve 38, the piloted valve 11, the unidirectional valve 39 and the lower part. of the piping 4. On the other hand, when the chamber 6 of the jack 8 is connected to the reservoir 2, the hydraulic fluid circulates successively through the lower part of the piping 4, the one-way valve 40, the piloted valve 11, the one-way valve 41 and the upper part of the piping 4. In both cases, the hydraulic fluid therefore passes through the piloted valve 11 in the same direction.

La présente invention trouve une application dans de nombreux domaines de la technique. A titre d'exemples, on citera le travail des métaux (presses pour filage, étirage, emboutissage, estampage) et le travail des sols et des roches (pelles hydrauliques travaillant en rétro ou en chargeuse, tracteur de génie civil ou agricole travaillant en rippage, etc.) et, d'une façon générale, dans tous les cas où un vérin hydraulique travaillant normalement en continu doit pouvoir fournir un effort dynamique momentané, en un point quelconque de sa course, pour surmonter un accroissement de résistance au cours du déplacement de sa tige de piston.The present invention finds application in many fields of technology. Examples include metalworking (presses for spinning, drawing, stamping, stamping) and soil and rock working (hydraulic shovels working in backhoe or loader, civil or agricultural engineering tractor working in ripping , etc.) and, in general, in all cases where a hydraulic cylinder normally working continuously must be able to provide a momentary dynamic force, at any point of its stroke, to overcome an increase in resistance during movement of its piston rod.

A titre d'exemple, on a représenté sur la fig. 7 une pelle hydraulique 42 comportant, de façon connue, une flèche 43, qui est montée pivotante à son extrémité arrière sur le châssis et qui peut être actionnée par un vérin 45, un balancier 46, qui est monté pivotant à son extrémité arrière sur l'extrémité avant de la flèche 43 et qui peut être actionné par un vérin 47, et un godet 48, muni de dents défonceuses 49, qui est monté pivotant en rétro à l'extrémité avant du balancier 46 et qui peut être actionné par un vérin tel que le vérin 8 de la fig. 1, par l'intermédiaire d'un palonnier 50 et d'une biellette 51. Le vérin 8 est porté par le balancier 46 sur lequel sont également disposés le bloc hydraulique 9 et l'accumulateur 14 de la fig. 1. Sur la fig. 8, on a représenté la partie avant de la pelle hydraulique 42 de la fig. 7, avec un balancier 46 équipé d'un godet'48 monté en chargeur.By way of example, there is shown in FIG. 7 a hydraulic shovel 42 comprising, in a known manner, an arrow 43, which is pivotally mounted at its rear end on the chassis and which can be actuated by a jack 45, a pendulum 46, which is pivotally mounted at its rear end on the 'front end of the boom 43 and which can be actuated by a jack 47, and a bucket 48, provided with knockout teeth 49, which is pivotally mounted in retro at the front end of the pendulum 46 and which can be actuated by a jack such as the jack 8 of FIG. 1, by means of a lifter 50 and a link 51. The jack 8 is carried by the pendulum 46 on which are also arranged the hydraulic block 9 and the accumulator 14 of FIG. 1. In fig. 8, the front part of the hydraulic shovel 42 of FIG. 7, with a pendulum 46 fitted with a bucket '48 mounted as a loader.

Il va de soi que la forme d'exécution de la présente invention qui a été décrite ci-dessus, a été donnée à titre d'exemple purement indicatif et nullement limitatif, et que de nombreuses modifications peuvent être facilement apportées par l'homme de l'art sans pour autant sortir du cadre de la présente invention tel qu'il est défini dans les revendications annexées. C'est ainsi notamment que la valve unidirectionnelle 13 (fig. 1) peut être remplacée par une valve pilotée identique à la valve pilotée 11 et qui, dans une position de repos, autorise le passage du fluide hydraulique à travers le tuyauterie 12 vers l'accumulateur 14 ou 29 et, dans une position de travail, coupe ledit passage. Dans ce cas, l'unité séquencielle de commande 17 doit actionner la valve pilotée 13 en même temps que la valve pilotée 10. En outre, lorsque les valves pilotées 10, 11, 15 et éventuellement 13 sont réalisées sous la forme d'électro-valves, l'unité séquentielle de commande 17 peut être réalisée sous forme de circuits électroniques à transistors ou à circuits intégrés. En outre, au lieu d'utiliser des électro-valves, on peut utiliser des valves pilotées par air comprimé ou par un fluide hydraulique. Dans ce dernier cas, l'unité séquentielle de commande 17 peut être elle-même constituée par des commutateurs et des circuits à retard fonctionnant à l'air comprimé ou avec un fluide hydraulique sous pression. En outre, dans ce qui précède, on a supposé que le vérin 8 travaille principalement à la poussée. S'il travaille principalement à la traction, il suffit de raccorder la tuyauterie 5 à la chambre 6 et la tuyauterie 4 à la chambre 7. Si le vérin 8 travaille aussi bien à la poussée qu'à la traction et si des impulsions hydrauliques doivent pouvoir être envoyées aussi bien dans la chambre 6 que dans la chambre 7, il suffit d'insérer dans la tuyauterie 5 un deuxième bloc hydraulique identique au bloc hydraulique 9 de la fig. 1 ou, plus simplement, de disposer une valve inverseuse dans les tuyauteries 4 et 5 entre le bloc hydraulique 9 et le vérin 8.It goes without saying that the embodiment of the present invention which has been described above, has been given by way of purely indicative and in no way limitative example, and that numerous modifications can be easily made by those skilled in the art. art without departing from the scope of the present invention as defined in the appended claims. Thus in particular that the unidirectional valve 13 (fig. 1) can be replaced by a piloted valve identical to the piloted valve 11 and which, in a rest position, authorizes the passage of the hydraulic fluid through the piping 12 to the accumulator 14 or 29 and, in a working position, cuts said passage. In this case, the sequential control unit 17 must actuate the piloted valve 13 at the same time as the piloted valve 10. In addition, when the piloted valves 10, 11, 15 and possibly 13 are produced in the form of electro- valves, the sequential control unit 17 can be produced in the form of electronic circuits with transistors or integrated circuits. In addition, instead of using electro-valves, it is possible to use valves controlled by compressed air or by a hydraulic fluid. In the latter case, the sequential control unit 17 may itself be constituted by switches and delay circuits operating with compressed air or with a hydraulic fluid under pressure. In addition, in the foregoing, it has been assumed that the jack 8 works mainly in the thrust. If it works mainly in traction, it is enough to connect the piping 5 to the chamber 6 and the piping 4 to the chamber 7. If the jack 8 works as well in the thrust as in the traction and if hydraulic impulses must being able to be sent both to chamber 6 and to chamber 7, it suffices to insert into the piping 5 a second hydraulic block identical to the hydraulic block 9 of FIG. 1 or, more simply, to have a reversing valve in the pipes 4 and 5 between the hydraulic block 9 and the jack 8.

Claims (11)

1. Process für supplying hydraulic fluid in a continuous manner and by controlled impulsion, with hydraulic energy accumulation, a hydraulic jack (8) normally operating continuously, characterized in that it comprises supplying a pressure chamber (6) of the hydraulic jack (8) with hydraulic fluid and simultaneously storing the hydraulic energy in an accumulator (14) from a pressurized fluid source (1) during the working stroke of the jack, whilst the pressure in the pressure chamber (6) of the jack remains below a selected value, so that the jack normally operates continuously, isolating the pressure chamber (6) of the hydraulic jack (8) from the pressurized fluid source (1) when the pressure in the jack pressure chamber reaches said selected value, connecting the pressure chamber (6) of the jack to a hydraulic fluid reservoir (2) in order to bring about a pressure drop in said pressure chamber, then isolating the pressure chamber of the jack from the reservoir, then linking the accumulator (14) solely with the pressure chamber (6) of the jack for supplying it with a hydraulic fluid impulsion, followed by the isolation of the pressure chamber of the jack from the accumulator (14) and the reestablishment of the link between the pressurized fluid source (1) on the one hand and the pressure chamber (6) and the accumulator (14) on the other, whereby they are maintained in this state for as long as the pressure within the pressure chamber does not again reach the selected value.
2. Apparatus making it possible to supply hydraulic fluid continiously and by controlled impulsion, a hydraulic jack normally operating continuously, comprising a pump (1), a fluid reservoir (2), a first pipe (4) having a first end and a second end which can be connected to a pressure chamber (6) of a hydraulic jack (8), a main distributor (3) connected to pump (1), to reservoir (2) and to the first end of the first pipe (4) for linking the latter selectively with the pump (1) or with the reservoir (2), and a hydraulic energy accumulator (14), characterized in that it also comprises a first controlled valve (10), which is connected to the first pipe (4) and to the reservoir (2) and which, in an inoperative position, isolates the first pipe from the reservoir and in a second working position establishes a link between the first pipe and the reservoir, a second controlled valve (11) inserted in the first pipe (4) between the second end thereof and the first controlled valve (10) and which, in the inoperative position, authorizes the passage of fluid into the first pipe and in a working position interrupts said passage, a second pipe (12) having first and second ends connected to the first pipe (4) respectively between the main distributor (3) and the second controlled valve (11) and between the latter and the second end of the first pipe (4), said accumulator (14) being connected to the second pipe (12), valve means inserted in the second pipe and having a third controlled valve (15) which, in an inoperative position, prevents the passage of fluid into the second pipe (12) from the accumulator to the second end of the second pipe and, in a working position, authorizes the passage of fluid from accumulator (14) to the second end of the second and first pipes (12, 4) and a control device (17, 25) having a pressure-sensitive means (23, 25), which is hydraulically connected to the first pipe (4) for giving an indication of the value of the hydraulic pressure prevailing in said first pipe, the control device being connected to the first, second and third controlled valves (10, 11, 15) and being «adjusted» when the pressure sensitive means (23, 25) indicates that the hydraulic pressure in the first pipe (4) has reached a selected value, in order to successively actuate the first, second and third controlled valves in their working positions and for then returning them to their inoperative positions.
3. Apparatus according to claim 2, characterized in that a regulatable nozzle (16) is arranged in the second pipe (12) between the third controlled valve (15) and the second end of the second pipe.
4. Apparatus according to claim 2 or 3, characterized in that it also comprises at least one other accumulator (29), whose membrane or diaphragm is prestressed at a pressure differing from that of the diaphragm or membrane of the first accumulator (14) and cocks (30,31) associated with accumulators (14, 29) for selectively connecting them to the second pipe (12).
5. Apparatus according to any one of the claims 2 to 4, characterized in that four one-way valve (38-41), connected as a Wheatstone bridge, I inserted in the first pipe (4), the latter being connected to the ends of one diagonal of the bridge, the second controlled valve (11) being mounted in the other diagonal of the bridge.
6. Apparatus according to any one of the claims 2 to 5, characterized in that the controlled valves (10, 11 and 15) are electrovalves and in that the control device (17, 25) comprises a normally open contact (BP) and/or (PR) and a sequential control unit (17), which comprises a first relay (Re) having a normally open contact (R), a second and a third relay (Mi and M2) both having a normally open and closed-timed contact (M1T) respectively (M2T), the duration of the timing of the third relay (M2) being greater than that of the second relay (M,) and a fourth relay (M3) having a normally closed contact (M3T) and timed for opening, a first end of the exciting coils (Re, M1, M2, M3, Sa, Sb and Sc) of the first, second, third and fourth relays and the first, second and third electrovalves (10, 11, 15) being connected to a first terminal (20) of a power supply (18), a second end of the exciting coils (Re, Mi, M2, Sa and Sb) of the first, second and third relays and the first and second electrovalves (10 and 11), the latter across the normally open contact (M1T) of the second relay (Mi), being connected to a second terminal (21) of the power supply on the one hand accross the normally open contact (BP) and/or (PR) of control device (17, 25) and on the other across the normally open contact (R) of the first relay (Re) and the normally closed contact (M3T) of the fourth relay (M3) connected in series, a second end of the exciting coils (M3) and (Sc) of the fourth relay and the third electrovalve (15) being connected to the junction point (22) between the normally open contact (R) of the first relay (Re) and the normally closed contact (M3T) of the fourth relay (M3) across the normally open contact (M2T) of the third relay (M2).
7. Apparatus according to claim 6, characterized in that the pressure-sensitive means (25) is a pressostat and in that the normally open contact of control device (17, 25) is the contact (PR) of said pressostat (25).
8. Apparatus according to claim 6, characterized in that the normally open contact of the control device is a push button contact (BP) and in that the pressure sensitive means (23) is a pressure gauge.
9. Apparatus according to claim 6, characterized in that the pressure sensitive means (25) is a pressostat and in that the control device (17, 25) has two normally open contacts (BP and PR), connected in parallel, one of them being a push button contact (BP) and the other is the contact (PR) of pressostat (25).
10. Civil engineering or agricultural machine comprising a working equipment (48) actuated by a hydraulic jack (8) normally operating continuously, characterized in that it incorporates a supply means according to any one of the claims 2 to 9 for supplying the hydraulic jack (8).
11. Apparatus according to any to one of the claims 2 to 9, characterized in that the valve means also incorporate a one-way valve (13) inserted in the second pipe (12) between the first end thereof and the accumulator (14), said one-way valve being fitted so as to authorize the passage of fluid into said second pipe only from the first end thereof towards accumulator (14).
EP84402194A 1983-11-02 1984-10-31 Continuous and intermittent feed of hydraulic fluid to a ram Expired EP0147256B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84402194T ATE31786T1 (en) 1983-11-02 1984-10-31 CONTINUOUS AND CONTROLLED PULSATING FEED OF PRESSURE FLUID TO A HYDRAULIC CYLINDER.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8317382A FR2554179B1 (en) 1983-11-02 1983-11-02 METHOD FOR SUPPLYING HYDRAULIC FLUID, CONTINUOUSLY AND BY CONTROLLED PULSE, A HYDRAULIC CYLINDER NORMALLY WORKING CONTINUOUSLY, AND DEVICE FOR IMPLEMENTING THE PROCESS
FR8317382 1983-11-02

Publications (2)

Publication Number Publication Date
EP0147256A1 EP0147256A1 (en) 1985-07-03
EP0147256B1 true EP0147256B1 (en) 1988-01-07

Family

ID=9293700

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84402194A Expired EP0147256B1 (en) 1983-11-02 1984-10-31 Continuous and intermittent feed of hydraulic fluid to a ram

Country Status (8)

Country Link
US (1) US4590763A (en)
EP (1) EP0147256B1 (en)
JP (1) JPS60172706A (en)
AT (1) ATE31786T1 (en)
CA (1) CA1246497A (en)
DE (1) DE3468491D1 (en)
ES (1) ES8603218A1 (en)
FR (1) FR2554179B1 (en)

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DE3328426A1 (en) * 1983-08-06 1985-02-21 Achim 8070 Ingolstadt Graul WORK TOOL FOR EARTH MOVEMENT DEVICES
JPS62119490U (en) * 1986-01-23 1987-07-29
US5116188A (en) * 1987-09-16 1992-05-26 Kabushiki Kaisha Kobe Seiko Sho Vibration suppressing device for wheeled construction equipment
DE3841369A1 (en) * 1988-12-08 1990-06-21 Kloeckner Humboldt Deutz Ag Hydraulic pulse system
JPH04140503A (en) * 1990-10-02 1992-05-14 Teisaku:Kk Pulsating apparatus for hydraulic cylinder
JP2964607B2 (en) * 1990-10-11 1999-10-18 日産自動車株式会社 Hydraulic supply device
BR9206342A (en) * 1991-08-07 1995-11-07 Microhydraulics Inc Active suspension system
JP3162384B2 (en) * 1991-09-04 2001-04-25 オー ウント カー オーレンスタイン ウント コツペル アクチエンゲゼルシヤフト Hydraulic devices for working machines with working devices
US5878569A (en) * 1996-10-21 1999-03-09 Caterpillar Inc. Energy conversion system
AU4047900A (en) * 1999-04-06 2000-10-23 Edwin E. Downer Jr Energy conservation system for earth-moving loading machines
US6655136B2 (en) 2001-12-21 2003-12-02 Caterpillar Inc System and method for accumulating hydraulic fluid
US6763661B2 (en) * 2002-05-07 2004-07-20 Husco International, Inc. Apparatus and method for providing vibration to an appendage of a work vehicle
US20140283915A1 (en) * 2013-03-21 2014-09-25 Caterpillar Inc. Hydraulic Control System Having Relief Flow Capture
GB2563238B (en) * 2017-06-07 2021-04-28 Caterpillar Sarl Fluid delivery system
US11493060B2 (en) 2019-06-04 2022-11-08 Industries Mailhot Inc. Hydraulic powering system and method of operating a hydraulic powering system
CN113090596B (en) * 2021-03-15 2022-09-16 中国科学院工程热物理研究所 Servomotor system with thermal redundancy backup oil supply and control method thereof

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FR2243357A1 (en) * 1974-04-18 1975-04-04 Poclain Sa Control device for body with reciprocating motion - electro-magnet and time relay control double acting ram distributor
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FR2439079A1 (en) * 1978-10-16 1980-05-16 Manceau Marcel Additional hydraulic circuit for reciprocating screw injection moulder - allows adjustment between precision moulding and high throughput cycle characteristics

Also Published As

Publication number Publication date
CA1246497A (en) 1988-12-13
ATE31786T1 (en) 1988-01-15
JPH0381011B2 (en) 1991-12-26
US4590763A (en) 1986-05-27
EP0147256A1 (en) 1985-07-03
ES537627A0 (en) 1986-01-01
FR2554179B1 (en) 1986-01-03
JPS60172706A (en) 1985-09-06
FR2554179A1 (en) 1985-05-03
ES8603218A1 (en) 1986-01-01
DE3468491D1 (en) 1988-02-11

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