FR2487019A2 - Pressure controlled safety device for hydraulic lifting device - uses electromagnetically operated control valve in non-return valve to hold pressure while load is being lowered - Google Patents

Pressure controlled safety device for hydraulic lifting device - uses electromagnetically operated control valve in non-return valve to hold pressure while load is being lowered Download PDF

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Publication number
FR2487019A2
FR2487019A2 FR8015913A FR8015913A FR2487019A2 FR 2487019 A2 FR2487019 A2 FR 2487019A2 FR 8015913 A FR8015913 A FR 8015913A FR 8015913 A FR8015913 A FR 8015913A FR 2487019 A2 FR2487019 A2 FR 2487019A2
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France
Prior art keywords
valve
load
hydraulic
cylinder
pressure
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Granted
Application number
FR8015913A
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French (fr)
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FR2487019B2 (en
Inventor
Gilbert Andre
Rene Charosse
Gilles Lambert
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RICHIER NLE INDLE
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RICHIER NLE INDLE
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Priority claimed from FR8006615A external-priority patent/FR2479358A1/en
Application filed by RICHIER NLE INDLE filed Critical RICHIER NLE INDLE
Priority to FR8015913A priority Critical patent/FR2487019A2/en
Publication of FR2487019A2 publication Critical patent/FR2487019A2/en
Application granted granted Critical
Publication of FR2487019B2 publication Critical patent/FR2487019B2/fr
Granted legal-status Critical Current

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Classifications

    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/01—Locking-valves or other detent i.e. load-holding devices
    • F15B13/015—Locking-valves or other detent i.e. load-holding devices using an enclosed pilot flow valve
    • 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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/003—Systems with load-holding valves
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
    • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single output member
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40576—Assemblies of multiple valves
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40576—Assemblies of multiple valves
    • F15B2211/40584—Assemblies of multiple valves the flow control means arranged in parallel with a check valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a return line
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out control
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
    • F15B2211/8633—Pressure source supply failure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
    • F15B2211/8636—Circuit failure, e.g. valve or hose failure

Abstract

The device is used for hydraulic shovels, and includes a pressure transducer in the hydraulic supply line to the working cylinder to actuate non-return in the case of reduced hydraulic pressure. The non-return valve has a control valve operated by an electromagnet. When the operators control lever is in the load lowering position a cam operates a switch which connects the electric supply to the contacts of the pressure transducer in the hydraulic supply line, so that the pressure transducer is effective only when the load is to be lowered. A controller directs the operation of the cylinder, and a hydraulic fluid reservoir is provided.

Description

La présente invention concerne un dispositif de sécurité pour au moins un vérin hydraulique de levage de charges, notamment pour des pelles hydrauliques, selon la revendication 1 du brevet principal. The present invention relates to a safety device for at least one hydraulic jack for lifting loads, in particular for hydraulic excavators, according to claim 1 of the main patent.

Le dispositif de sécurité selon la présente invention est destiné aux vérins du type indiqué,compor- tant chacun au moins une conduite, qui sert à l'alimentation de son compartiment actif , et qui inclut une tuyauterie flexible, exposée à des ruptures accidentelles, en particulier dans les conditions sévères d'environnement qui sont celles par exemple des pelles hydrauliques, utilises sur les chantiers de travaux publics. The safety device according to the present invention is intended for the cylinders of the type indicated, each comprising at least one pipe, which serves to supply its active compartment, and which includes a flexible pipe exposed to accidental breakage, particularly in the severe environmental conditions which are those for example hydraulic excavators, used on public works sites.

Be dispositif de sécurité selon la présente invention est caractérisé en ce que le dispositif de pilotage du clapet anti-retour est commandé dans le sens de la fermeture dudit clapet, à partir de la pression régnant dans la conduite, servant à l'alimenta- tion du compartiment actif du vérin, en un point de ladite conduite, situé entre ledit clapet et la tuyauterie flexible, par l'intermédiaire d'une valve électromagnétique en position de repos, le circuit électrique de commande de cette valve comportant un premier contact de travail, qui est actionné par un capteur de pression, relié au point mentionné de ladite conduite d'alimentation, et qui est monté en série avec un second contact de travail, actionné seulement en phase de descente de la charge. The safety device according to the present invention is characterized in that the control device of the non-return valve is controlled in the closing direction of said valve, from the pressure prevailing in the pipe, used for feeding the active compartment of the cylinder, at a point of said pipe, located between said valve and the flexible pipe, via an electromagnetic valve in the rest position, the electrical control circuit of this valve comprising a first working contact , which is actuated by a pressure sensor, connected to the mentioned point of said supply line, and which is connected in series with a second working contact, actuated only during the descent phase of the load.

Be dispositif de sécurité selon la présente invention est également applicable à plusieurs vérins hydrauliques de levage de charges, qui sont alimentés en parallèle à partir d'un unique distributeur de liquide hydraulique, à commande manuelle'ou asservie
À titre d'exemples, on a décrit ci-dessous et illustré schématiquement au dessin annexé deux formes de réalisation de l'invention.The safety device according to the present invention is also applicable to a plurality of hydraulic lifting cylinders which are fed in parallel from a single hydraulic fluid distributor, manually controlled or servo-controlled.
By way of example, two embodiments of the invention are described below and illustrated schematically in the appended drawing.

La figure 1 est le schéma du circuit hydraulique d'un unique vérin de levage à double effet, notamment pour une pelle hydraulique. Figure 1 is the diagram of the hydraulic circuit of a single double-acting lifting cylinder, in particular for a hydraulic excavator.

La figure 2 est le schéma du circuit hydraulique commun de plusieurs vérins hydrauliques de levage de charges, alimentés en parallèle. Figure 2 is a diagram of the common hydraulic circuit of several hydraulic lifting cylinders loads, supplied in parallel.

Sur la figure 1, 1 désigne un verin hydraulique de levage à double effet, équipant par exemple une pelle hydraulique d'un type connu ; la désigne son piston et lb la tige de ce dernier, dont l'extrémité supérieure, extérieure au vérin 1, supporte, par l'intermédiaire dun plateau, une charge C.Dans le compartiment inférieur, à grande section, 1c du vérin 1,et dans son compartiment supérieur, à petite section, Id, débouchent respectivement, deux conduites d'alimentation ainsi constituées : chaque conduite d'alimentation comporte une première partie rigide, 2c ou 2d, fixe par rapport au vérin hydraulique I et aux organes mobiles de la pelle, dont il est solidaire, ainsi qu'une seconde partie rigide, 2a ou 2b, solidaire du cassis de la pelle hydraulique, sur lequel sont montés, à poste fixe, notamment un réservoir de liquide hydraulique 3 et une pompe hydraulique 4.Les deux parties rigides, par exemple 2a et 2c, d'une meame conduite d'alimentation d'un compartiment du vérin, par exemple Ic, sont reliées entre elles par une tuyauterie flexible, 2e ou 2f, qui est évidemment exposée à des ruptures accidentelles dans les dures conditions d'environnement qui sont celles de l'utilisation des pelles hydrauliques sur les chantiers de travaux publics. Sur le châssis de la pelle hydraulique est également monté un distributeur 5 à trois positions, 1, Il et N (neutre) et quatre voies, 5a à 5d. Dans la forme de réalisation illustrée, ce distributeur 5 est à commande manuelle, c'est-àdire que son passage de la position N à l'une des deux positions I et il est commandé manuellement.A titre de être variante, le distributeur 5 pourraitZà commande asservie. In Figure 1, 1 designates a double-acting hydraulic lifting jack, equipping for example a hydraulic excavator of a known type; 1a denotes its piston and lb the rod thereof, whose upper end, external to the cylinder 1, supports, through a tray, a load C.In the lower compartment, large section, 1c of the cylinder 1, and in its upper compartment, with a small section, Id, respectively open two supply lines thus constituted: each supply line comprises a first rigid portion, 2c or 2d, fixed relative to the hydraulic cylinder I and the movable members of the shovel, which it is secured, and a second rigid portion, 2a or 2b, integral with the blackcurrant of the hydraulic shovel, on which are mounted, fixed station, including a hydraulic fluid reservoir 3 and a hydraulic pump 4. The two rigid parts, for example 2a and 2c, of a same supply line of a cylinder compartment, for example Ic, are interconnected by a flexible pipe, 2e or 2f, which is obviously exposed to breaks. access identelles in the harsh environmental conditions that are those of the use of hydraulic excavators on public works sites. On the chassis of the hydraulic excavator is also mounted a distributor 5 with three positions, 1, II and N (neutral) and four channels, 5a to 5d. In the illustrated embodiment, this dispenser 5 is manually controlled, that is to say that its passage from the position N to one of the two positions I and it is manually controlled. As a variant, the distributor 5 could be controlled slave.

Dans l'exemple illustré,7voies 5a et 5b du distributeur 5 sont raccordées respectivement aux extrémités des deux parties rigides, 2a et 2b,des conduites d'alimentation des compartiments 1c et Id du vérin 1 sa voie 5c est reliée à la pompe 4, tandis que sa voie 5d est reliée au réservoir de liquide hydraulique 3 à travers un clapet de contre-pression 6. On a indiqué par des flèches les liaisons que le distributeur 5 établit entre, d'une part, ses voies 5a, 5b, et, d'autre part, ses voies 5c, 5d, respectivement dans ses positions I et IX ; dans sa position N, il obture les extrémités correspondantes des conduites d'alimentation 2a et 2b, et relie le refoulement de la pompe 4 au clapet de contre-pression 6, qui débouche dans le réservoir de liquide hydraulique 3. In the example shown, 7channels 5a and 5b of the distributor 5 are respectively connected to the ends of the two rigid parts, 2a and 2b, supply lines of the compartments 1c and Id of the jack 1, its channel 5c is connected to the pump 4, while its lane 5d is connected to the hydraulic fluid reservoir 3 through a back-pressure valve 6. The links which the distributor 5 establishes between, on the one hand, its lanes 5a, 5b, and on the other hand, its pathways 5c, 5d, respectively in its positions I and IX; in its position N, it closes the corresponding ends of the supply lines 2a and 2b, and connects the discharge of the pump 4 to the counter-pressure valve 6, which opens into the hydraulic fluid reservoir 3.

Dans la forme de réalisation illustrée, le dispositif de sécurité selon la présente invention comporte un clapet anti-retour 7, à dispositif de pilotage, une valve électromagnétique 8, et un limiteur de pression 10, ces différents composants pouvant être fixés de préférence sur une ou deux plaques de base, qui peuvent être solidaires du corps du vérin 1, ou des organes mobiles de la pelle auxquels le corps du vérin est lui-même fixé. In the illustrated embodiment, the safety device according to the present invention comprises a non-return valve 7, with a control device, an electromagnetic valve 8, and a pressure limiter 10, these different components being able to be fixed preferably on a or two base plates, which may be integral with the body of the cylinder 1, or movable members of the excavator to which the body of the cylinder is itself fixed.

Selon la présente invention, le clapet antiretour 7, est inséré, par l'intermédiaire de ses tubulures 7i et 7j, dans la partie rigide, 2c, de la conduite d'alimentation du compartiment inférieur, Ic, du vérin 1, qui commande le levage de la charge C. Le dispositif de pilotage de ce clapet anti-retour 7 comporte lui-meme une entrée de commande de la fermeture du clapet, 7a. Un clapet antiretour de ce genre est susceptible de nombreuses formes de réalisation, dont certaines sont bien connues, et qu'il n'est donc pas nécessaire de décrire en détail. According to the present invention, the non-return valve 7 is inserted, via its pipes 7i and 7j, into the rigid part 2c of the feed pipe of the lower compartment Ic of the cylinder 1 which controls the lifting the load C. The control device of this non-return valve 7 itself comprises a control input of the closing of the valve, 7a. A check valve of this type is susceptible of many embodiments, some of which are well known, and therefore need not be described in detail.

La valve électromagnétique 8 comporte deux positions, A et 3, et trois voies : d'un côté, une voie unique, 8a, reliée à l'entrée de commande, 7a, du disposi tif de pilotage du clapet anti-retour 7 ; d'un autre côté, deux voies, 8c et 8d ; la voie 8c est reliée à un point de la seconde partie rigide, 2c, de la conduite d'alimentation du compartiment inférieur 1c du vérin 1, qui est situé entre le clapet anti-retour 7 et ledit compartiment inférieur du vérin i.c, ou un dispositif de freinage, 14, associé audit compartiment,1c, et réalisé de façon à limiter seulement le débit du fluide hydraulique qui traverse la conduite 2c en provenance du compartiment Ic ; la voie 8d est d'autre part reliée au réservoir de liquide hydraulique 3 par une conduite comportant deux parties rigides, 12a et 12b, raccordées entre elles par une tuyauterie flexible, 12c. Le limiteur de pression,1O, qui peut être d'un type usuel, mais de préférence à limite réglable, est inséré entre la conduite 2c et une bifurcation,12d,de la conduite 12b. The electromagnetic valve 8 has two positions, A and 3, and three channels: on one side, a single channel, 8a, connected to the control input, 7a, the control device of the non-return valve 7; on the other hand, two lanes, 8c and 8d; the channel 8c is connected to a point of the second rigid portion 2c of the supply line of the lower compartment 1c of the cylinder 1, which is located between the non-return valve 7 and said lower compartment of the cylinder ic, or a braking device, 14, associated with said compartment, 1c, and constructed so as to limit only the flow of hydraulic fluid through the pipe 2c from the compartment Ic; 8d the channel is further connected to the hydraulic fluid reservoir 3 by a pipe having two rigid parts, 12a and 12b, connected together by a flexible pipe, 12c. The pressure limiter, 10, which may be of a conventional type, but preferably an adjustable limit, is inserted between the pipe 2c and a bifurcation, 12d, of the pipe 12b.

Selon la présente invention, l'enroulement d'excitation, 8g, de la valve électromagnétique 8 est inséré dans un circuit électrique de commande, comportant un premier contact de travail, 16, qui est actionné par -un capteurde pression 17, relié'à point de la conduite 2c, situé entre le clapet anti-retour 7 et la tuyauterie flexible correspondante, 2e ; ce premier contact de travail 16 est d'autre part monté en série avec un second contact de travail, 18, actionné, par l'intermédiaire dune came i9,à partir du distributeur 5, par exemple par l'intermédiaire d'une tige d'accouplement 20 ; la came 19 est aménagée de manière à laisser le contact de travail 18 en position ouverte lorsque le distributeur 5 se trouve dans l'une quelconque de ses deux positions I et N, ladite came 19 ne produisant la fermeture du second contact de travail 18 que lorsque le distributeur occupe sa position Il, correspondant à la descente de la charge C. Dans l'exemple de réalisation illustré, on a indiqué sous la forme d'une batterie d'accumulateur électrique 21 un générateur de courant destiné à alimenter l'enroulement d'excitation 8g de la valve électromagnétique 8 lorsque les deux contacts de travail 16 et 18 sont fermés simultanément. According to the present invention, the excitation winding, 8g, of the electromagnetic valve 8 is inserted into an electrical control circuit, having a first working contact, 16, which is actuated by a pressure sensor 17, connected to point of the pipe 2c, located between the non-return valve 7 and the corresponding flexible pipe, 2e; this first working contact 16 is, on the other hand, connected in series with a second working contact, 18, actuated, via a cam i9, from the distributor 5, for example by means of a rod of coupling 20; the cam 19 is arranged to leave the working contact 18 in the open position when the distributor 5 is in any of its two positions I and N, said cam 19 producing the closure of the second working contact 18 that when the distributor occupies its position II, corresponding to the descent of the load C. In the exemplary embodiment illustrated, there is indicated in the form of an electric accumulator battery 21 a current generator for supplying the winding excitation 8g of the electromagnetic valve 8 when the two working contacts 16 and 18 are closed simultaneously.

Be fonctionnement du circuit hydraulique qui vient d'etre décrit est le suivant
Lorsque le distributeur 5 est placé dans sa position I et que la pompe 4 est actionnée par son moteur (non représenté), ladite pompe aspire du liquide hydraulique dans le réservoir 3 et le refoule, par l'intermédiaire des voies 5c, 5a du distributeur 5, dans les conduites 2a, 2e, 2c,puis dans la tubulure 7i du clapet anti-retour 7 le liquide hydraulique sous pression franchit alors ledit clapet anti-retour 7 dans son sens direct et il est refoulé par la tubulure 7j, la conduite 2c et le dispositif de
14 freinage/- traversé dans son sens d'inactivité - jusque dans le compartiment inférieur 1c du vérin 1.Il en résulte un soulèvement progressif du piston la du vérin i et de la charge C, le compartiment supérieur, In, dudit vérin se vidant au-fur-et-à-mesure à travers les conduites 2d, 2f, 2b, les voies 5b et 5d du distributeur 5,et le clapet de contre-pression 6,le liquide toumErhdans le réservoir 3.Be the operation of the hydraulic circuit that has just been described is the following
When the distributor 5 is placed in its position I and the pump 4 is actuated by its motor (not shown), said pump sucks hydraulic fluid into the tank 3 and delivers it through the channels 5c, 5a of the distributor 5, in the pipes 2a, 2e, 2c, then in the tubing 7i of the non-return valve 7 the hydraulic fluid under pressure then passes said non-return valve 7 in its direct direction and it is discharged by the pipe 7j, the pipe 2c and the device
14 braking / - crossed in its direction of inactivity - into the lower compartment 1c of the cylinder 1.It results in a progressive lifting of the piston of the cylinder i and the load C, the upper compartment, In, said cylinder emptying progressively through the lines 2d, 2f, 2b, the channels 5b and 5d of the distributor 5, and the backpressure valve 6, the liquid toumErhdans the reservoir 3.

Lorsque par contre le distributeur 5 est amené dans sa position Il, la pompe 4 refoule le liquide sous pression, par les conduites 2b, 2f et 2d, dans le compartimont supérieu2du vérin 1, tandis que son compartiment inférieur ic est relié au réservoir 3 à travers le dispositif de freinage 14 - traversé dans son sens d'activité -,le clapet anti retour 7, et le clapet de contre-pression 6 ; ce dernier maintient cependant dans la conduite 2c, en dessous du clapet'7, une pression notablement supérieure à celle régnant dans le réservoir 3, et suffisante pour faire maintenir la fermeture du premier contact de travail 16 par le capteur de pression 17 ; comme le second contact de travail 18 est alors maintenu fermé par la came 19, l'enroulement 8g de la valve électromagnétique 8 est alimenté, si bien que ladite valve 8 est dans sa position B, pour laquelle elle relie,par ses voies 8a et 8d, l'entrée de commande, 7a, du dispositif de pilotage du clapet anti-retour 7 à la conduite 12b, où règne la même pression que dans le réservoir 3 ; comme cette pression est inférieure à celle maintenue par le clapet de contre-pression 6 dans la tubulure 7i du clapet anti-retour 7, ce dernier est ouvert et ne s'oppose donc pas à la vidange du compartiment inférieur 1c du vérin 1 vers le réservoir 3. When, on the other hand, the distributor 5 is brought into its position 11, the pump 4 delivers the liquid under pressure through the lines 2b, 2f and 2d into the upper compartment 2 of the cylinder 1 while its lower compartment ic is connected to the tank 3 to through the braking device 14 - traversed in its direction of activity -, the nonreturn valve 7, and the counter-pressure valve 6; the latter however maintains in the pipe 2c, below the valve '7, a significantly higher pressure than that prevailing in the reservoir 3, and sufficient to maintain the closure of the first working contact 16 by the pressure sensor 17; as the second working contact 18 is then kept closed by the cam 19, the winding 8g of the electromagnetic valve 8 is energized, so that said valve 8 is in its position B, for which it connects, through its channels 8a and 8d, the control input, 7a, the control device of the non-return valve 7 to the pipe 12b, where the same pressure as in the reservoir 3; as this pressure is lower than that maintained by the backpressure valve 6 in the tubing 7i of the non-return valve 7, the latter is open and therefore does not oppose the emptying of the lower compartment 1c of the cylinder 1 towards the tank 3.

Il en résulte une descente du piston la du vérin 1 et de la charge C, cette descente étant rendue progressive par une manoeuvre appropriée du distribFteur 5g et sa vitesse étant limitée par le dispositif de freinage 14.This results in a descent of the piston 1a of the cylinder 1 and the load C, this descent being made progressive by appropriate operation of the distributor 5g and its speed being limited by the braking device 14.

Lorsque par contre le distributeur 5 se trouve dans sa position N, l'ouverture du second contact de travail,18,coupe l'alimentation de la valve électromagnéti- que 8, qui reste dans sa position de repos A, où elle s'oppose, par l'intermédiaire du dispositif de pilotage du clapet anti-retour 7, à l'ouverture de ce dernier dans le sens inverse. Be clapet anti-retour 7 s'oppose donc à la vidange du compartiment inférieur îc du vérin 1, dont le piston la maintient par suite la charge C à une hauteur fixe. When, on the other hand, the distributor 5 is in its position N, the opening of the second working contact, 18, interrupts the supply of the electromagnetic valve 8, which remains in its rest position A, where it opposes , through the control device of the non-return valve 7, the opening of the latter in the opposite direction. Be check valve 7 is therefore opposed to the emptying of the lower compartment 1c of the cylinder 1, whose piston maintains the load C following a fixed height.

Il résulte de ce qui précède que la descente de la charge n'est rendue possible, par le maintien en position ouverte du clapet anti-retour 7, que si les deux contacts de travail 16 et 18 sont fermés simultanément, ce qui exige , simultanémen",le distributeur 5 soit dans sa position II,etqlffl regne dans la conduite 2c une pression notablement supérieure à celle du réservoir 3. It follows from the foregoing that the descent of the load is made possible, by maintaining the open position of the check valve 7, only if the two working contacts 16 and 18 are closed simultaneously, which requires, simultanémen ", the distributor 5 is in its position II, andqlffl reign in the pipe 2c a significantly higher pressure than the reservoir 3.

7
Dans tous les autres cas, le clapet anti-retourJstoppose à la descente de la charge. C'est le cas notamment si la tuyauterie flexible 2e est rompue accidentellement, puisqu'alors le capteur de pression 17 ouvre le premier contact de travail 16, et cela quelle que soit la position du distributeur 5. Si c'est par contre la tuyauterie flexible 2f qui est rompue accidentellement, le clapet anti-retour 7 ne cesse pas de s'opposer à la redescente de la charge C si le distributeur 5-occupe l'une de ses deux positions I et N, puisque le second contact de travail, 18, est alors ouvert.Si par contre le distributeur 5 se trouve dans sa position II, correspondant à la descente de la charge, les deux contacts de travail 16 et 18 restant fermés, la valve électromagnétique 8 reste dans sa position 3, où elle suppose à la refermeture du clapet anti-retour 7, si bien que la descente progressive de la charge C se poursuit, à moins que le distributeur 5 ne soit ramené dans sa position N, auquel cas la charge C est arrêtée à une hauteur fixe.Si par contre les deux tuyauteries flexibles 2e et 2f sont arrachées simultanément, le capteur de pression 17 n'est plus soumis sensiblement qugà la pression atmosphérique, si bien qu'il ouvre le premier contact de travail 16, ce qui a pour effet de ramener la valve 8 dans sa position de repos A, of elle provoque la refermeture du clapet anti-retour 7 ; ceci interromss la descente de la charge C.7
In all other cases, the non-return valve opposes the descent of the load. This is particularly the case if the flexible pipe 2e is accidentally broken, since then the pressure sensor 17 opens the first working contact 16, and this whatever the position of the distributor 5. If it is against the piping 2f flexible which is broken accidentally, the non-return valve 7 does not stop to oppose the descent of the load C if the distributor 5-occupies one of its two positions I and N, since the second contact work , 18, is then open.Si against the distributor 5 is in its position II, corresponding to the descent of the load, the two working contacts 16 and 18 remaining closed, the electromagnetic valve 8 remains in its position 3, where it assumes the reclosing of the non-return valve 7, so that the progressive descent of the load C continues, unless the distributor 5 is returned to its position N, in which case the load C is stopped at a fixed height .If on the other hand the two pipes 2 and 2f flexible are removed simultaneously, the pressure sensor 17 is no longer substantially subjected to atmospheric pressure, so that it opens the first working contact 16, which has the effect of reducing the valve 8 in its position resting A, of it causes the reclosing of the non-return valve 7; this interrupts the descent of the charge C.

Le dispositif de sécurité selon la présente invention évite donc certainement la redescente brutale de la charge C en cas de rupture de l'une au moins des tuyauteries flexibles. The safety device according to the present invention therefore certainly avoids the abrupt reduction of the load C in case of rupture of at least one of the flexible pipes.

La figure 2 représente le circuit .de deux vérins hydrauliques de levage de charges, 1A et 13, qui sont alimentés en parallèle à partir d'un unique distributeur de liquide hydraulique > 5 ; les principaux composants de ce circuit hydraulique ont été désignés par les mêmes références que sur la figure 1, les indices A et 3 indiquant que certains d'entre eux sont associés respectivement aux vérins 1A et 13. Selon la présente invention, les premiers contacts de travail, 16A et 16B, commandés respectivement par les capteurs de pression, 17A et 173, reliés respectivement aux premières conduites d'alimentation 2A et 2B des deux vérins, lA et 1B, sont montés en série entre, dtune part, les enroulements de commande, connec tés en parallèle, des valves électromagnétiques, 8 et 8B, associées respectivement aux vérins lÀ et 13, et, d'autre part, un second contact, commun, de travail, 18.Dans l'exemple illustré, le distributeur 5 est à commande asservie, ctest-à-dire que son passage de la position N à l'une des deux positions I et II est commandé par lune des deux conduites d'asservissement 5I et 5II, dont l'alimentation en fluide hydraulique est commandée, notamment par le conducteur de la pelle hydraulique, à partir du poste de conduite.Dans le cas de cette réalisation, le second contact de travail 18 peut être commandé par un vérin 22, alimenté lui-même par une dérivation de la conduite d'asservissement 51I, de manière que le contact de travail 18 soit fermé exclusivement lorsque le distributeur 5 se trouve dans sa position II, correspondant au levage des charges0
Si l'une au moins des tuyauteries flexibles 2e et 2eB est rompue accidentellement, la mise à la pression atmosphérique du-capteur de pression 17A ou 173 provoque l'ouverture du premier contact de travail 16A ou 163 ; si le distributeur 5 se trouve dans sa position I ou N, le second contact de travail 18 étant ouvert, les valves électromagnétiques 8A et 8B restent au repos, si bien que les clapets anti-retour, 7A et 7B, s'opposent b la redescente de la charge.Si par contre le distributeur 5 est dans sa position II, correspondant à la descente de la charge, l'ouverture de l'un des premiers contacts de travail 16A et 16B provoque le retour au repos des deux valves électromagnétiques 8A et 8B et, par suite, la refermeture des clapets anti-retour 7A et 73 et l'immobilisation de la charge à une même hauteur. Sn cas de rupture de l'une seulement des tuyauteries flexibles 2f et 2fB, la levée de la charge se poursuit ou s'arrête, selon que le distributeur 5 est dans sa position I ou N, tandis que la descente de la charge est interrompue et celle-ci est arrêtée à une même hauteur si le distributeur 5 se trouve dans sa position II-.FIG. 2 shows the circuit of two hydraulic lift cylinders, 1A and 13, which are fed in parallel from a single hydraulic fluid distributor>5; the main components of this hydraulic circuit have been designated by the same references as in FIG. 1, the indices A and 3 indicating that some of them are associated respectively with the cylinders 1A and 13. According to the present invention, the first contacts of 16A and 16B, respectively controlled by the pressure sensors, 17A and 173, respectively connected to the first supply lines 2A and 2B of the two cylinders, 1A and 1B, are connected in series between, on the one hand, the control windings , connected in parallel, electromagnetic valves, 8 and 8B, respectively associated with the cylinders 11 and 13, and, secondly, a second contact, common, working, 18.In the example shown, the distributor 5 is with controlled control, that is to say that its passage from the position N to one of the two positions I and II is controlled by one of the two control lines 5I and 5II, the hydraulic fluid supply is controlled e, in particular by the driver of the hydraulic excavator, from the driving position. In the case of this embodiment, the second working contact 18 can be controlled by a jack 22, itself powered by a bypass of the control conduit. 51I servo, so that the working contact 18 is closed exclusively when the distributor 5 is in its position II, corresponding to the lifting of loads
If at least one of the flexible pipes 2e and 2e is accidentally broken, the pressurization of the pressure sensor 17A or 173 causes the opening of the first working contact 16A or 163; if the distributor 5 is in its position I or N, the second working contact 18 being open, the electromagnetic valves 8A and 8B remain at rest, so that the nonreturn valves, 7A and 7B, are opposed b If the distributor 5 is in its position II, corresponding to the descent of the load, the opening of one of the first working contacts 16A and 16B causes the return to rest of the two solenoid valves 8A and 8B and, consequently, the reclosing of the non-return valves 7A and 73 and the immobilization of the load at the same height. In case of failure of only one of the flexible pipes 2f and 2fB, the lifting of the load continues or stops, depending on whether the distributor 5 is in its position I or N, while the descent of the load is interrupted. and it is stopped at the same height if the distributor 5 is in its II- position.

La présente invention n'est pas limitée aux formes de réalisation précédemment décrites0 Elle englobe toutes leurs variantes.  The present invention is not limited to the previously described embodiments. It encompasses all their variants.

Claims (4)

REVENDICAXIONSREVENDICAXIONS 1. Dispositif de sécurité pour au moins un vérin hydraulique (1) de levage de charges (C), notamment pour des pelles hydrauliques, selon la revendication t du brevet principal, caractérisé en ce que le dispositif de pilotage du clapet anti-retour (7) est commandé dans le sens de la fermeture dudit clapet (7), à partir de la pression régnant dans la conduite (2c) servant à ltalimentation du compartiment actif (ic) du vérin (1), en un point de ladite conduite (2c), situé entre ledit clapet (7) et la tuyauterie flexible (2e), par l'intermédiaire d'une valve électromagnétique (8) en position de repos (A), le circuit électrique de commande de cette valve (8) comportant un premier contact de travail (16) qui est actionné par un capteur de pression (17), relié au point mentionné de ladite conduite d'alimentation (2c), et qui est monté en série avec un second contact de travail (18), actionné seulement en phase de descente de la charge (C).1. Safety device for at least one hydraulic jack (1) for lifting loads (C), particularly for hydraulic excavators, according to claim t of the main patent, characterized in that the control device of the non-return valve ( 7) is controlled in the closing direction of said valve (7), from the pressure in the pipe (2c) for feeding the active compartment (ic) of the cylinder (1), at a point of said pipe ( 2c), located between said valve (7) and the flexible pipe (2e), via an electromagnetic valve (8) in the rest position (A), the electric control circuit of this valve (8) comprising a first working contact (16) which is actuated by a pressure sensor (17), connected to the mentioned point of said supply line (2c), and which is connected in series with a second working contact (18), operated only during the descent phase of the load (C). 2. Dispositif selon la revendication 1, caractérisé en ce que le second contact de travail (18) est actionné, par exemple par llintermédiaire d'une came (19), à partir d'un organe de commande (5) du vérin de levage (1), notamment d'un distributeur de liquide hydraulique sous pression, à conslande manuelle ou asservie, de façon que ledit second contact (18) soit fermé seulement lorsque l'organe de commande du vérin (5) est dans sa position correspondant à la descente de la charge.2. Device according to claim 1, characterized in that the second working contact (18) is actuated, for example by means of a cam (19), from a control member (5) of the lifting cylinder. (1), in particular a pressurized hydraulic fluid dispenser, manual or servo-controlled, so that said second contact (18) is closed only when the control member of the cylinder (5) is in its position corresponding to the descent of the load. 3. Dispositif selon l'une quelconque des revendications 1 et 2, caractérisé en ce que La valve électroma gnétique (8) est aménagée de façon à relier l'entrée de commande (7a) du dispositif de pilotage du clapet antiretour (7), soitolorsque ladite valve (8) est en position de repos (A)å n point de la conduite d'alimentation (2c)situé entre le clapet anti-retour (7) et le compartiment actif (lc) du vérin (1), soit, lorsque laite valve (s) est en position de travail (B), à une conduite (12b) aboutissant au réservoir de liquide hydraulique (3).3. Device according to any one of claims 1 and 2, characterized in that the electromagnetic valve (8) is arranged to connect the control input (7a) of the control device of the non-return valve (7), orwhen said valve (8) is in the rest position (A) at the point of the supply line (2c) between the nonreturn valve (7) and the active compartment (1c) of the cylinder (1), or when said valve (s) is in working position (B), to a pipe (12b) leading to the hydraulic fluid reservoir (3). 4. Dispositif de sécurité pour plusieurs vérins hydrauliques (1A, 1B) de levage de charges, alimentés en parallèle à partir d'un unique distributeur de liquide hydraulique (5), à commande manuelle ou asservie, selon l'une quelconque des revendications 1 à 5, caractérisé en ce que les premiers contacts de travail (16A, 16B)comman- dés respectivement par les capteurs de pression (17A, 173), reliés respectivement aux conduites d'alimenta- compartiments actifs des tion (2A, 23) desZdifférents vérins (1A, 1B), sont montés en série entre, d'une part, les enroulements de commande, connectés en parallèle, des valves électromagnétiques (8A, 8B), associées respectivement aux différents vérins (1A, 13) et, d'autre part, un second contact,communSde travail (18), actionné seulement en phase de descente des charges, par exemple à partir du distributeur (5). Safety device for a plurality of load lifting hydraulic cylinders (1A, 1B), fed in parallel from a single manual or servo-controlled hydraulic fluid distributor (5) according to any one of claims 1 to 5 to 5, characterized in that the first working contacts (16A, 16B) respectively controlled by the pressure sensors (17A, 173), respectively connected to the active supply lines (2A, 23) of the different cylinders (1A, 1B), are connected in series between, on the one hand, the control windings connected in parallel, the electromagnetic valves (8A, 8B) associated respectively with the different cylinders (1A, 13) and, on the other hand, a second common working contact (18) operated only during the descent phase of the loads, for example from the distributor (5).
FR8015913A 1980-03-25 1980-07-18 Pressure controlled safety device for hydraulic lifting device - uses electromagnetically operated control valve in non-return valve to hold pressure while load is being lowered Granted FR2487019A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR8015913A FR2487019A2 (en) 1980-03-25 1980-07-18 Pressure controlled safety device for hydraulic lifting device - uses electromagnetically operated control valve in non-return valve to hold pressure while load is being lowered

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8006615A FR2479358A1 (en) 1980-03-25 1980-03-25 Mechanical digger lifting jack with safety device - monitors pressure after flexible pipeline section to control automatic non-return valve which can be selectively inhibited
FR8015913A FR2487019A2 (en) 1980-03-25 1980-07-18 Pressure controlled safety device for hydraulic lifting device - uses electromagnetically operated control valve in non-return valve to hold pressure while load is being lowered

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FR2487019A2 true FR2487019A2 (en) 1982-01-22
FR2487019B2 FR2487019B2 (en) 1984-07-13

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1347103A3 (en) * 2002-03-06 2004-01-07 Fiat Kobelco Construction Machinery S.p.A. Control of an operating arm of an earthmoving vehicle
GB2440610A (en) * 2006-08-02 2008-02-06 Husco Int Inc Component failure protection valve with overpressure opening
EP1520994A3 (en) * 2003-10-02 2011-10-19 Deere & Company Hydraulic arrangement and related procedure
US20210372085A1 (en) * 2018-10-17 2021-12-02 Caterpillar Sarl Drift-prevention valve device, blade device, and working machine

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2328868A1 (en) * 1975-10-21 1977-05-20 Monsun Tison Ab Hydraulic motor line leakage controller - has nonreturn valve in parallel with variable choke valve

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2328868A1 (en) * 1975-10-21 1977-05-20 Monsun Tison Ab Hydraulic motor line leakage controller - has nonreturn valve in parallel with variable choke valve

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
EXBK/79 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1347103A3 (en) * 2002-03-06 2004-01-07 Fiat Kobelco Construction Machinery S.p.A. Control of an operating arm of an earthmoving vehicle
US7076896B2 (en) 2002-03-06 2006-07-18 Cnh America Llc Control for an operating arm of an earthmoving vehicle
EP1520994A3 (en) * 2003-10-02 2011-10-19 Deere & Company Hydraulic arrangement and related procedure
GB2440610A (en) * 2006-08-02 2008-02-06 Husco Int Inc Component failure protection valve with overpressure opening
US7409825B2 (en) 2006-08-02 2008-08-12 Husco International, Inc. Hydraulic system with a cylinder isolation valve
GB2440610B (en) * 2006-08-02 2011-03-02 Husco Int Inc Hydraulic system with a cylinder isolation valve
US20210372085A1 (en) * 2018-10-17 2021-12-02 Caterpillar Sarl Drift-prevention valve device, blade device, and working machine
US11885099B2 (en) * 2018-10-17 2024-01-30 Caterpillar Sarl Drift-prevention valve device, blade device, and working machine

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