EP0776426B1 - Hydraulic control device for a double acting cylinder - Google Patents

Hydraulic control device for a double acting cylinder Download PDF

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Publication number
EP0776426B1
EP0776426B1 EP94928429A EP94928429A EP0776426B1 EP 0776426 B1 EP0776426 B1 EP 0776426B1 EP 94928429 A EP94928429 A EP 94928429A EP 94928429 A EP94928429 A EP 94928429A EP 0776426 B1 EP0776426 B1 EP 0776426B1
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EP
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Prior art keywords
jack
cylinder
hydraulic
valve
distribution block
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EP94928429A
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German (de)
French (fr)
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EP0776426A1 (en
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Alain Bourgeois
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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
    • F15B7/00—Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors
    • F15B7/005—With rotary or crank input
    • F15B7/006—Rotary pump input
    • 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
    • F15B7/00—Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors
    • F15B7/008—Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors with rotary output

Definitions

  • the present invention relates to a device for hydraulic control of a double-acting cylinder.
  • Double acting hydraulic cylinders are generally supplied with pressurized oil by a electro-hydraulic power plant to which a oil distribution block including a distributor hydraulic or a set of valves controlling the cylinder operation in both directions, especially in the case of differential operation.
  • Such a hydraulic supply device has the disadvantage that if the piping cylinder supply lines are flexible, these pipes may rupture, pressurized oil may leak to the exterior from the broken piping, the cylinder is no longer supplied and the load actuated by the cylinder is no longer held. This can result in in some cases, serious property damage and even possibly accidents that could involve the life of operators.
  • the kinematics of the mobile assembly controlled by the jack must take into account the increase in size due to the presence of the electro-hydraulic power plant nearby of the cylinder.
  • the use of rigid piping does not does not prevent any leakage from the distributor, leaks that always appear when uses a conventional drawer dispenser.
  • the first set HZ of figure 4 is a system comprising a double-acting cylinder combined with a certain number of valves so that if one external pipe the cylinder rod cannot get out of the jack; however the rod can at any time back off if the return line breaks.
  • the KZ system which also includes a cylinder double effect is associated with a certain number of valves to prevent any retraction of the cylinder rod in the event of pipeline rupture; however, nothing is planned to retain the rod at the outlet.
  • this device is extremely complex since it requires kinematics suitable for optimum security, similar to that of the invention.
  • the present invention aims to remedy these disadvantages of providing a feeder hydraulics with a particularly simple design, reduced size, effectively protecting, due to its design, the cylinder against a burst of the piping supplying it with pressurized oil or against a distributor leak.
  • this hydraulic supply device a double-acting cylinder, comprising a central electro-hydraulic supplying pressurized oil to cylinder via piping and block of distribution, is characterized in that the block of distribution, fixed on the cylinder body, directly or at immediate proximity to it, through rigid connecting members, said distribution block comprising a non-return valve connected upstream to a supply piping extending to the power plant electro-hydraulic and downstream to the right chamber of the hydraulic cylinder, via an internal conduit to said block, said valve preventing any return of oil to the central or outward in the event of the rupture of the supply piping and a control valve normally closed electromagnetic connecting the conduit internal to the left chamber of the cylinder, characterized in that that said distribution block further comprises a second internal conduit to said distribution block connecting the left chamber of the cylinder to the oil return piping to the tank via a check valve electromagnetic control, normally closed and incorporated in said distribution block.
  • the following hydraulic supply device the invention which is shown in the drawing, is expected to supply pressurized oil to a double cylinder effect 1 with differential operation.
  • This cylinder 1 comprises a cylindrical body 2 inside which is mounted at sliding a piston 3 secured to a piston rod 4 extending axially outward, through a end of the cylinder body 2, to control the displacement of any load.
  • the piston 3 delimits, inside the cylinder body 2, two chambers, namely a straight chamber 2a in which the rod extends piston 4, and a left chamber 2b.
  • Cylinder 1 is pressurized oil supplied from a power plant electro-hydraulic 5 comprising, in the manner usual, an oil pump 6 driven by a motor electric 7 and the suction port of which is connected by through a pipeline on which is connected a filter 8 to an oil tank 9.
  • the central electro-hydraulic 5 also includes piping 11 oil return to reservoir 9.
  • the operation of the hydraulic supply device of the jack 1 is as follows: to cause the re-entry of the rod, that is to say its displacement from right to left in the drawing, the pump 6 is started. the electro-hydraulic unit 5, which delivers pressurized oil, through the non-return valve 14 of the distribution block 12, into the right chamber 2 a of the jack 1. The excitation of the electromagnetic valve 18 is also controlled which then passes into the open position, the valve 16 remaining in its closed rest position.
  • the pressurized oil arriving through the piping 15 and the internal conduit 13 can then gradually fill the right chamber 2 a of the jack 2, while the oil being in the left chamber 2 b of this jack can return to the tank 9 by passing through the valve 18, in the open position, the internal conduit 17 and the pipe 11 returning to the tank 9.
  • valve 18 To cause the reverse movement, that is to say the exit of the piston rod 4, the valve 18 is kept in the closed position and the valve 16 is however excited to move it to the open position, which establishes communication between the two right chambers 2 a and left 2 b of the jack 1.
  • the pressurized oil from the electro-hydraulic unit 5 flows through the non-return valve 14, into the internal conduit 13 and at from the latter towards the two chambers 2 a , 2 b of the jack 1.
  • the device conforms to one or other of the variants of the invention is advantageously usable in the particular area of the tail lift in particular for a vehicle for which it has not yet never been provided with such a safety device and protection in case of broken pipes pressurized fluid supply.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Fluid-Pressure Circuits (AREA)

Description

La présente invention concerne un dispositif de commande hydraulique d'un vérin à double effet.The present invention relates to a device for hydraulic control of a double-acting cylinder.

Les vérins hydrauliques à double effet sont généralement alimentés en huile sous pression par une centrale électro-hydraulique à laquelle est adjoint un bloc de distribution de l'huile comprenant un distributeur hydraulique ou un ensemble de clapets commandant le fonctionnement du vérin dans les deux sens, notamment dans le cas d'un fonctionnement différentiel. Le vérin hydraulique est monté à proximité immédiate de l'élément dont il doit provoquer le mouvement et il est relié, par des tuyauteries souples ou rigides, au bloc de distribution situé à distance, généralement à proximité immédiate de la centrale électro-hydraulique.Double acting hydraulic cylinders are generally supplied with pressurized oil by a electro-hydraulic power plant to which a oil distribution block including a distributor hydraulic or a set of valves controlling the cylinder operation in both directions, especially in the case of differential operation. The cylinder hydraulically mounted in close proximity to the element which it must cause movement and it is connected, by flexible or rigid piping, to the block of remote distribution, usually close immediately from the electro-hydraulic unit.

Un tel dispositif d'alimentation hydraulique présente l'inconvénient que, si les tuyauteries d'alimentation du vérin sont souples, ces tuyauteries peuvent se rompre, l'huile sous pression peut fuir à l'extérieur à partir de la tuyauterie rompue, le vérin n'est alors plus alimenté et la charge actionnée par le vérin n'est plus maintenue. Il peut en résulter, dans certains cas, des dommages matériels sérieux et même éventuellement des accidents pouvant mettre en cause la vie des opérateurs.Such a hydraulic supply device has the disadvantage that if the piping cylinder supply lines are flexible, these pipes may rupture, pressurized oil may leak to the exterior from the broken piping, the cylinder is no longer supplied and the load actuated by the cylinder is no longer held. This can result in in some cases, serious property damage and even possibly accidents that could involve the life of operators.

Si le circuit de liaison hydraulique entre le vérin et le bloc de distribution associé à la centrale électro-hydraulique est constitué de tuyauteries rigides, la cinématique de l'ensemble mobile commandé par le vérin doit tenir compte de l'augmentation de l'encombrement dû à la présence de la centrale électro-hydraulique à proximité du vérin. De plus, l'utilisation de tuyauteries rigides ne prévient en rien les fuites éventuelles provenant du distributeur, fuites qui apparaissent toujours lorsqu'on utilise un distributeur classique à tiroir.If the hydraulic connection circuit between the cylinder and the distribution block associated with the electro-hydraulic power plant consists of rigid pipes, the kinematics of the mobile assembly controlled by the jack must take into account the increase in size due to the presence of the electro-hydraulic power plant nearby of the cylinder. In addition, the use of rigid piping does not does not prevent any leakage from the distributor, leaks that always appear when uses a conventional drawer dispenser.

C'est par exemple le cas d'un dispositif conforme au préambule de la première revendication, décrit dans le brevet européen EP-A-0031000. Selon ce document antérieur et en se référant à la figure 4, il est décrit un dispositif pour assurer, en cas de rupture de canalisation, une totale stabilité du mouvement d'un hayon élévateur ; pour y parvenir et en combinaison avec un système mécanique adéquat, on prévoit deux commandes par vérin du type double effet venant limiter chacun la course du hayon respectivement dans un sens et dans l'autre, en cas de rupture de canalisation ; à titre d'exemple, le premier ensemble HZ de la figure 4 est un système comportant un vérin double effet combiné avec un certain nombre de clapets pour qu'en cas de rupture d'une canalisation extérieure la tige du vérin ne puisse pas sortir du vérin ; en revanche, la tige peut à tout moment reculer en cas de rupture de la canalisation de retour. Inversement, le système KZ qui comprend également un vérin double effet est associé à un certain nombre de clapets pour interdire tout recul de la tige du vérin en cas de rupture de canalisation ; en revanche, rien n'est prévu pour retenir la tige en sortie.This is for example the case of a device conforming to the preamble of the first claim, described in the European patent EP-A-0031000. According to this earlier document and with reference to Figure 4, there is described a device to ensure, in case of breakage of channeling, total stability of the movement of a tailgate elevator; to achieve this and in combination with a adequate mechanical system, two controls per double acting type cylinder each limiting the stroke of the tailgate respectively in one direction and in the other, in pipeline rupture; for example, the first set HZ of figure 4 is a system comprising a double-acting cylinder combined with a certain number of valves so that if one external pipe the cylinder rod cannot get out of the jack; however the rod can at any time back off if the return line breaks. Conversely, the KZ system which also includes a cylinder double effect is associated with a certain number of valves to prevent any retraction of the cylinder rod in the event of pipeline rupture; however, nothing is planned to retain the rod at the outlet.

Outre cette double commande, ce dispositif est extrêmement complexe puisqu'il nécessite une cinématique adaptée pour obtenir une sécurité optimum, analogue à celle de l'invention.In addition to this dual control, this device is extremely complex since it requires kinematics suitable for optimum security, similar to that of the invention.

La présente invention vise à remédier à ces inconvénients en procurant un dispositif d'alimentation hydraulique de conception particulièrement simple, d'un encombrement réduit, protégeant efficacement, de par sa conception, le vérin à l'encontre d'un éclatement de la tuyauterie l'alimentant en huile sous pression ou à l'encontre d'une fuite du distributeur.The present invention aims to remedy these disadvantages of providing a feeder hydraulics with a particularly simple design, reduced size, effectively protecting, due to its design, the cylinder against a burst of the piping supplying it with pressurized oil or against a distributor leak.

A cet effet ce dispositif d'alimentation hydraulique d'un vérin à double effet, comportant une centrale électro-hydraulique alimentant en huile sous pression le vérin par l'intermédiaire d'une tuyauterie et d'un bloc de distribution, est caractérisé en ce que le bloc de distribution, fixé sur le corps du vérin, directement ou à proximité immédiate de celui-ci, par l'intermédiaire d'organes de liaison rigides, ledit bloc de distribution comportant un clapet anti-retour relié en amont à une tuyauterie d'alimentation s'étendant jusqu'à la centrale électro-hydraulique et en aval, à la chambre droite du vérin hydraulique, par un conduit interne audit bloc, ledit clapet interdisant tout retour d'huile vers la centrale ou vers l'extérieur en cas de la rupture de la tuyauterie d'alimentation et un clapet à commande électromagnétique normalement fermé reliant le conduit interne à la chambre gauche du vérin, caractérisé en ce que ledit bloc de distribution comporte en outre un second conduit interne audit bloc de distribution reliant la chambre gauche du vérin à la tuyauterie de retour d'huile vers le réservoir par l'intermédiaire d'un clapet à commande électromagnétique, normalement fermé et incorporé dans ledit bloc de distribution .To this end, this hydraulic supply device a double-acting cylinder, comprising a central electro-hydraulic supplying pressurized oil to cylinder via piping and block of distribution, is characterized in that the block of distribution, fixed on the cylinder body, directly or at immediate proximity to it, through rigid connecting members, said distribution block comprising a non-return valve connected upstream to a supply piping extending to the power plant electro-hydraulic and downstream to the right chamber of the hydraulic cylinder, via an internal conduit to said block, said valve preventing any return of oil to the central or outward in the event of the rupture of the supply piping and a control valve normally closed electromagnetic connecting the conduit internal to the left chamber of the cylinder, characterized in that that said distribution block further comprises a second internal conduit to said distribution block connecting the left chamber of the cylinder to the oil return piping to the tank via a check valve electromagnetic control, normally closed and incorporated in said distribution block.

On comprend bien maintenant le fonctionnement du vérin double effet conforme à l'invention selon un mode différentiel qui ne peut être obtenu que par la combinaison de trois clapets disposés à l'intérieur d'un bloc de distribution flasqué sur le vérin à double effet de telle manière que les liaisons d'entrée et de sortie qui sont nécessairement souples dans l'application dont il est question, puisse le cas échéant se rompre sans pour autant occasionner une descente ou un repliage intempestif du hayon élévateur engendrant pour tout le système une totale insécurité, ce qui serait le cas si l'on utilisait séparément les commandes décrites en HZ ou en KZ dans le document antérieur EP-A-0031000.We now understand how the double-acting cylinder according to the invention according to a mode differential which can only be obtained by the combination of three valves arranged inside a distribution block mounted on the double-acting cylinder in such a way that the input and output links which are necessarily flexible in the application which it is question, can if necessary break without as much cause an untimely descent or folding of the tail lift generating for the whole system a total insecurity, which would be the case if we used separately the commands described in HZ or KZ in the previous document EP-A-0031000.

On décrira ci-après, à titre d'exemple non limitatif, une forme d'exécution de la présente invention en référence au dessin annexé qui est un schéma hydraulique d'un dispositif d'alimentation d'un vérin à fonctionnement différentiel.We will describe below, by way of example not limiting, an embodiment of the present invention with reference to the attached drawing which is a diagram hydraulic supply device for a cylinder differential operation.

Le dispositif d'alimentation hydraulique suivant l'invention qui est représenté sur le dessin, est prévu pour alimenter en huile sous pression un vérin à double effet 1 à fonctionnement différentiel. Ce vérin 1 comporte un corps cylindrique 2 à l'intérieur duquel est monté à coulissement un piston 3 solidaire d'une tige de piston 4 s'étendant axialement à l'extérieur, à travers une extrémité du corps 2 du vérin, pour commander le déplacement d'une charge quelconque. Le piston 3 délimite, à l'intérieur du corps 2 du vérin, deux chambres à savoir une chambre droite 2a dans laquelle s'étend la tige de piston 4, et une chambre gauche 2b. Le vérin 1 est alimenté en huile sous pression à partir d'une centrale électro-hydraulique 5 comprenant, de la manière habituelle, une pompe à huile 6 entraínée par un moteur électrique 7 et dont l'orifice d'aspiration est relié, par l'intermédiaire d'une canalisation sur laquelle est branché un filtre 8, à un réservoir d'huile 9. La centrale électro-hydraulique 5 comporte également une tuyauterie 11 de retour de l'huile au réservoir 9.The following hydraulic supply device the invention which is shown in the drawing, is expected to supply pressurized oil to a double cylinder effect 1 with differential operation. This cylinder 1 comprises a cylindrical body 2 inside which is mounted at sliding a piston 3 secured to a piston rod 4 extending axially outward, through a end of the cylinder body 2, to control the displacement of any load. The piston 3 delimits, inside the cylinder body 2, two chambers, namely a straight chamber 2a in which the rod extends piston 4, and a left chamber 2b. Cylinder 1 is pressurized oil supplied from a power plant electro-hydraulic 5 comprising, in the manner usual, an oil pump 6 driven by a motor electric 7 and the suction port of which is connected by through a pipeline on which is connected a filter 8 to an oil tank 9. The central electro-hydraulic 5 also includes piping 11 oil return to reservoir 9.

Suivant l'invention la circulation de l'huile alimentant le vérin 1 est commandée par un bloc de distribution 12 qui est solidarisé directement sur le corps 2 du vérin 1 ou bien à proximité immédiate de celui-ci, par l'intermédiaire d'organes de liaison rigides 10. Ce bloc de distribution 12 comporte :

  • un premier conduit interne 13 muni à l'une de ses extrémités d'un clapet anti-retour 14, lequel est relié à l'orifice de refoulement de la pompe 6 par l'intermédiaire d'une tuyauterie extérieure et souple 15, l'autre extrémité dudit conduit 13 assurant directement l'alimentation en huile sous pression de la chambre droite 2a du vérin 1 d'une part et, à travers un clapet 16 à commande électromagnétique normalement fermé, de la chambre gauche 2b du vérin 1 d'autre part, et
  • un second conduit 17 interne audit bloc de distribution 12 reliant la chambre gauche 2b du vérin 1 et la tuyauterie de retour d'huile 11 vers le réservoir 9, par l'intermédiaire d'un clapet 18 à commande électromagnétique, normalement fermé.
According to the invention, the circulation of the oil supplying the jack 1 is controlled by a distribution block 12 which is secured directly to the body 2 of the jack 1 or else in the immediate vicinity thereof, by means of members. rigid connection 10. This distribution block 12 comprises:
  • a first internal conduit 13 provided at one of its ends with a non-return valve 14, which is connected to the discharge orifice of the pump 6 by means of an external and flexible pipe 15, the other end of said duct 13 directly supplying the pressurized oil to the right chamber 2 a of the jack 1 on the one hand and, through a valve 16 with normally closed electromagnetic control, to the left chamber 2 b of the jack 1 d on the other hand, and
  • a second conduit 17 internal to said distribution block 12 connecting the left chamber 2b of the jack 1 and the oil return pipe 11 to the tank 9, by means of a valve 18 with electromagnetic control, normally closed.

Le fonctionnement du dispositif d'alimentation hydraulique du vérin 1 est le suivant : pour provoquer la rentrée de la tige, c'est-à-dire son déplacement de la droite vers la gauche sur le dessin, on met en marche la pompe 6 de la centrale électro-hydraulique 5, laquelle refoule de l'huile sous pression, à travers le clapet anti-retour 14 du bloc de distribution 12, dans la chambre droite 2a du vérin 1. On commande également l'excitation du clapet électromagnétique 18 qui passe alors en position d'ouverture, le clapet 16 restant dans sa position de repos fermée. L'huile sous pression arrivant par la tuyauterie 15 et le conduit interne 13 peut alors remplir progressivement la chambre droite 2a du vérin 2, tandis que l'huile se trouvant dans la chambre gauche 2b de ce vérin peut retourner au réservoir 9 en passant à travers le clapet 18, en position d'ouverture, le conduit interne 17 et la tuyauterie 11 de retour au réservoir 9.The operation of the hydraulic supply device of the jack 1 is as follows: to cause the re-entry of the rod, that is to say its displacement from right to left in the drawing, the pump 6 is started. the electro-hydraulic unit 5, which delivers pressurized oil, through the non-return valve 14 of the distribution block 12, into the right chamber 2 a of the jack 1. The excitation of the electromagnetic valve 18 is also controlled which then passes into the open position, the valve 16 remaining in its closed rest position. The pressurized oil arriving through the piping 15 and the internal conduit 13 can then gradually fill the right chamber 2 a of the jack 2, while the oil being in the left chamber 2 b of this jack can return to the tank 9 by passing through the valve 18, in the open position, the internal conduit 17 and the pipe 11 returning to the tank 9.

Pour provoquer le mouvement inverse c'est-à-dire la sortie de la tige de piston 4, on maintient le clapet 18 en position de fermeture et on excite par contre le clapet 16 pour le faire passer en position d'ouverture, ce qui établit une communication entre les deux chambres droite 2a et gauche 2b du vérin 1. L'huile sous pression provenant de la centrale électro-hydraulique 5 s'écoule à travers le clapet anti-retour 14, dans le conduit interne 13 et à partir de celui-ci vers les deux chambres 2a,2b du vérin 1. Comme la surface active gauche du piston 3 est supérieure à la surface active droite, annulaire, de ce piston, la force tendant à faire sortir la tige de piston 4, vers la droite, c'est-à-dire celle qui est due à la pression appliquée sur la face gauche du piston 3, est supérieure à la force tendant à faire rentrer cette tige de piston 4, c'est-à-dire celle qui est due à la pression appliquée sur la face active annulaire droite du piston 3. Le mouvement du piston 3 et de sa tige 4 vers la droite amène l'huile contenue dans la chambre droite 2a à être chassée de cette chambre et cette huile passe dans le bloc de distribution 12, à travers le clapet 16 en position d'ouverture pour arriver à la chambre gauche 2b, conjointement avec l'huile sous pression fournie directement à partir de la centrale électro-hydraulique 5.To cause the reverse movement, that is to say the exit of the piston rod 4, the valve 18 is kept in the closed position and the valve 16 is however excited to move it to the open position, which establishes communication between the two right chambers 2 a and left 2 b of the jack 1. The pressurized oil from the electro-hydraulic unit 5 flows through the non-return valve 14, into the internal conduit 13 and at from the latter towards the two chambers 2 a , 2 b of the jack 1. As the left active surface of the piston 3 is greater than the right, annular active surface of this piston, the force tending to force the piston rod out 4, to the right, that is to say that which is due to the pressure applied to the left face of the piston 3, is greater than the force tending to cause this piston rod 4 to enter, that is to say say that which is due to the pressure applied to the right annular active face of the piston 3. The movement of the piston 3 and its rod 4 to the right brings the oil contained in the right chamber 2 a to be driven from this chamber and this oil passes into the distribution block 12, through the valve 16 in the open position to arrive to the left chamber 2 b , together with the pressurized oil supplied directly from the electro-hydraulic unit 5.

Si, pour une raison quelconque, la tuyauterie 15 d'alimentation du vérin 1 en huile sous pression vient à se rompre, le vérin 1 se trouve être protégé grâce au clapet anti-retour 14. L'huile contenue dans les deux chambres 2a,2b du vérin 1 ne peut en effet s'écouler vers l'extérieur, à travers la tuyauterie rompue 15, du fait de la présence du clapet anti-retour 14 qui forme un barrage hermétique. De plus, de par sa conception incluant le clapet anti-retour 14 et le clapet 18 à commande électromagnétique, normalement fermé, le bloc de distribution 12 est préservé des fuites internes contrairement aux distributeurs classiques. Le vérin 1 ne peut donc pas se vider de son huile et ceci garantit la sécurité de fonctionnement du vérin 1, surtout lorsqu'il est utilisé pour le déplacement de charges lourdes.If for any reason the piping 15 supply of cylinder 1 with pressurized oil comes to break, the cylinder 1 is protected by the check valve 14. The oil in both chambers 2a, 2b of the cylinder 1 cannot indeed flow towards the exterior, through the broken pipe 15, due to the presence of the non-return valve 14 which forms a barrier hermetic. In addition, by design including the non-return valve 14 and control valve 18 electromagnetic, normally closed, the block distribution 12 is protected from internal leaks unlike conventional distributors. Cylinder 1 does therefore cannot empty its oil and this guarantees the operational safety of cylinder 1, especially when is used for moving heavy loads.

Le dispositif conforme à l'une ou l'autre des variantes de l'invention est avantageusement utilisable dans le domaine particulier du hayon élévateur notamment pour véhicule pour lequel jusqu'à ce jour il n'avait jamais été prévu de tel dispositif de sécurité et de protection en cas de rupture des canalisations d'alimentation en fluide sous pression.The device conforms to one or other of the variants of the invention is advantageously usable in the particular area of the tail lift in particular for a vehicle for which it has not yet never been provided with such a safety device and protection in case of broken pipes pressurized fluid supply.

Claims (2)

  1. Device for the hydraulic feeding of a double-action jack (1) comprising an electro-hydraulic unit (5) which feeds the jack (1) with oil under pressure via piping (15) and a distribution block (12) fitted on the body of the jack (1) directly or in its immediate vicinity by means of rigid connection elements (10), the said distribution block comprising a one-way valve (14) connected upstream to the feed piping (15) with extends as far as the electro-hydraulic unit (5) and downstream to the right-hand chamber (2a) of the hydraulic jack (1) via an internal duct (13) of the said block (12), the said valve (14) preventing any return of oil to the unit (5) or to the outside in the event that the feed piping (15) should burst, and a valve (16) controlled electromagnetically which is normally closed, connecting the internal duct (13) to the left-hand chamber (2b) of the jack (1), characterized in that the said distribution block also comprises a second duct (17) internal to the said distribution block (12) which connects the left-hand chamber (2b) of the jack (1) to the oil return piping (11) leading back to the reservoir (9) via an electromagnetically controlled valve (18) which is normally closed and its incorporated in the said distribution block (12).
  2. Application of the device according to the preceding claim in a lifting platform, notably for vehicles.
EP94928429A 1993-09-22 1994-09-22 Hydraulic control device for a double acting cylinder Expired - Lifetime EP0776426B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9311276 1993-09-22
FR9311276A FR2710372B1 (en) 1993-09-22 1993-09-22 Hydraulic control device for a double-acting cylinder.
PCT/FR1994/001109 WO1995008715A1 (en) 1993-09-22 1994-09-22 Hydraulic control device for a double acting cylinder

Publications (2)

Publication Number Publication Date
EP0776426A1 EP0776426A1 (en) 1997-06-04
EP0776426B1 true EP0776426B1 (en) 1998-12-23

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EP94928429A Expired - Lifetime EP0776426B1 (en) 1993-09-22 1994-09-22 Hydraulic control device for a double acting cylinder

Country Status (5)

Country Link
EP (1) EP0776426B1 (en)
AU (1) AU7786094A (en)
DE (1) DE69415559D1 (en)
FR (1) FR2710372B1 (en)
WO (1) WO1995008715A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2365407B (en) 2000-05-25 2003-10-08 Bamford Excavators Ltd Hydraulic system for wheeled loader
US7159662B2 (en) 2004-02-18 2007-01-09 Fmc Technologies, Inc. System for controlling a hydraulic actuator, and methods of using same
US7137450B2 (en) 2004-02-18 2006-11-21 Fmc Technologies, Inc. Electric-hydraulic power unit
US6998724B2 (en) 2004-02-18 2006-02-14 Fmc Technologies, Inc. Power generation system

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2953118A (en) * 1956-04-05 1960-09-20 Francis S Flick Port fitting
US4079988A (en) * 1977-02-28 1978-03-21 Peabody International Corporation Elevating tailgate
DE2950852A1 (en) * 1979-12-18 1981-09-24 Vereinigte Flugtechnische Werke Gmbh, 2800 Bremen LOADING DEVICE FOR LOAD VEHICLES
DE4120170A1 (en) * 1991-06-19 1992-12-24 Bosch Gmbh Robert PRESSURE-OPERABLE WORKING CYLINDER
DE9305980U1 (en) * 1993-04-20 1993-08-05 Leibfried Maschinenbau GmbH, 71083 Herrenberg Pneumatic cylinder

Also Published As

Publication number Publication date
DE69415559D1 (en) 1999-02-04
EP0776426A1 (en) 1997-06-04
AU7786094A (en) 1995-04-10
FR2710372B1 (en) 1995-11-17
FR2710372A1 (en) 1995-03-31
WO1995008715A1 (en) 1995-03-30

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