EP0935715A1 - Device for holding in position the rod of a pressure cylinder - Google Patents

Device for holding in position the rod of a pressure cylinder

Info

Publication number
EP0935715A1
EP0935715A1 EP97913266A EP97913266A EP0935715A1 EP 0935715 A1 EP0935715 A1 EP 0935715A1 EP 97913266 A EP97913266 A EP 97913266A EP 97913266 A EP97913266 A EP 97913266A EP 0935715 A1 EP0935715 A1 EP 0935715A1
Authority
EP
European Patent Office
Prior art keywords
valve
chamber
holding device
safety valve
rod
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.)
Granted
Application number
EP97913266A
Other languages
German (de)
French (fr)
Other versions
EP0935715B1 (en
Inventor
Jean-Luc Andre
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lohr Industrie SA
Original Assignee
Lohr Industrie SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Lohr Industrie SA filed Critical Lohr Industrie SA
Publication of EP0935715A1 publication Critical patent/EP0935715A1/en
Application granted granted Critical
Publication of EP0935715B1 publication Critical patent/EP0935715B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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

Definitions

  • the present invention relates to a device for holding in position the rod of a hydraulic cylinder. It also relates to the detection of leaks in the return circuit of the motor chamber.
  • Hydraulic cylinders are frequently used as drive members in the lifting and lowering assemblies of a support structure. These assemblies are well known and used in the field of transport, but also in the building and other places on which the movements' raising and lowering of a load are daily and require repeated efforts and greater than human force.
  • a cylinder is conventionally maintained under load by a non-return valve inserted in the cylinder supply circuit in the direction passing towards the outlet chamber of the rod.
  • This function of maintaining under load fulfills its role as long as the sealing of the valve can be preserved. This exists at the start because of the quality controls carried out in the manufacturing workshops.
  • the valve may gradually or suddenly exhibit a leakage after a certain period of time, for various reasons linked to operation or aging, or even to a minor fault of origin which has gone unnoticed.
  • a cause a geometric defect, for example of sphericity of the ball, a solid impurity present in the oil circuit and coming to rest on the valve seat or any other cause of poor mechanical contact. or local allowance between the valve body and its seat.
  • This holding function turns out to be compulsory in all use cases in which the safety of holding in the support position is an important if not essential condition.
  • the valve To ensure that a function as important as the safety of maintenance is maintained without fail, the valve must offer a total guarantee of watertightness. This total guarantee cannot exist and, for this reason, when security demands, the lifting cylinders are associated with mechanical blocking-locking devices, for example locking pins or with safety stops.
  • the purpose of these mechanical blocking-locking or abutment devices is to ensure the safety of the load-bearing structures being held in position during a prolonged outage. This holding in position represents a safety measure for goods and people that the cylinder and its control circuit cannot ensure alone in an infallible manner due to the always possible leaks at the non-return valve.
  • the object of the invention is to dispense with the use of these additional mechanical retaining means, necessary to ensure the safety of the maintenance in the case of a hydraulic cylinder locked in the load retaining position.
  • the invention relates to a device for maintaining the position of the rod of an hydraulic cylinder at least with a single effect, comprising a chamber, for example from the output of its rod, and to the at least one non-return valve mounted in the chamber supply circuit, passing towards this chamber, the holding device consisting of a hydraulic isolation block through which this chamber is supplied, characterized in that:
  • the non-return valve called the primary valve is completed by a safety check valve separate from the primary valve and mounted upstream in the supply circuit of this chamber, passing in the same direction towards this chamber,
  • an airlock presenting at each of its two inlets and outlets a non-return valve including, on the one hand, the primary valve placed closest to this chamber, and the safety valve,. means for deferred closing of the safety valve with respect to that of the primary valve,. a means for controlling the opening of the two valves.
  • the invention finds multiple applications in many fields when it comes to lifting-lowering a load with maintenance in the retaining position and more particularly in the extended position of the cylinder rod.
  • the hydraulic device according to the invention is inexpensive
  • Figure 1 is a general schematic sectional view showing the holding device according to the invention mounted on the supply legs of a cylinder; .
  • Figure 2 is a longitudinal sectional view of a first embodiment of the holding device; .
  • Figures 3 and 4 are respectively enlarged views in longitudinal section of the central part of the holding device in the case of the two variants, one with conical valve and the other with fully sealed valve, with valves shown in the state closed ;
  • Figure 5 is a general schematic sectional view showing the simplified variant of the holding device according to one invention mounted on the supply branches of a cylinder with valves shown in one closed state;
  • Figure 6 is a longitudinal sectional view of the simplified variant of the holding device.
  • the device for holding in position the rod of a hydraulic cylinder 1 is in the form of an isolation assembly 2 mounted between a branch 3 and another branch 4 for supplying working fluid respectively to a reentry 5 and an outlet chamber 6 of a rod 7 of the hydraulic cylinder
  • This isolation assembly 2 forms a hydraulic block 8 containing a chamber-lock 9 called for reasons of convenience simply lock.
  • This airlock has a lower orifice 10 provided with a primary non-return valve 11 in hydraulic connection with the outlet chamber 6 of the rod 7 of the jack and opposite, an upper orifice 12 provided with a safety non-return valve 13 in hydraulic communication with a hydraulic inlet 14 extended by a transverse channel 15 for supplying motive fluid to the outlet chamber 6 from the hydraulic inlet 14.
  • the primary non-return 11 and safety check valves 13 are physically separate and mounted pass-through in the direction from the top to the bottom of the figures, that is to say in the direction of supply of the outlet chamber 6 of the rod 7 from the hydraulic inlet 14.
  • the primary valve 11 is produced in the form of a non-return ball valve 16 forced into a closing reminder against a seat of suitable shape, for example conical 17 traversed in its center by the lower orifice 10.
  • the return force is generated by a return spring 18 trapped in a housing 19 at the lower end of the isolation block 2.
  • the safety check valve 13 is produced in a first variant in the form of a frustoconical body 20 with an active conical surface in contact in the closed position with a circular rim 21 of an annular shoulder 22 traversed in its center by the 'upper orifice 12.
  • the safety valve 13 opens conventionally and automatically by the incident pressure.
  • the opening of the safety valve 13 can be controlled by a means external to the isolation block 2, for example by the driving force of the hydraulic fluid under pressure supplying the re-entry chamber of the rod or any other means. It also causes the controlled opening of the primary valve 11 to be cascaded. To do this, the safety valve 13 is extended downwards by a lower control rod 23 which carries, threaded on its lateral surface, a return spring 24 in the closed position.
  • This control rod 23 ends with a free end with a straight thrust front which can pass through the lower orifice 10 of the airlock 9 to move by pushing the body of the primary valve 11 when opening, that is to say away from its seat 17 against the elastic return force provided by the spring 18.
  • the safety valve 13 is integral with a means of slowing down its stroke in closing reminder so as to delay its closing with respect to that of the primary valve 11. This can thus guarantee 1 * absence of significant dynamic pressure and therefore of flow in the airlock 9 during the closing phase of the safety valve 13.
  • This characteristic makes it possible in particular to envisage the use of a seal to perfect the seal and thus increase the efficiency of the safety valve.
  • This type of valve with seal will be called a fully sealed valve 26. It constitutes the ideal means of closing the airlock 9 and of enhanced guarantee of the position held under load of the cylinder rod.
  • This variant is represented in FIG. 4 in the form of a fully sealed valve 26 with a seal 27, for example an O-ring resting on a groove-shaped seat 28.
  • These fully sealed valves are not very resistant to dynamic pressure due to the risks of extrusion of the seal that it can cause.
  • the conical surface of the body of the safety valve 13 shown in FIG. 3 is either partially or completely lined with a coating or a seal. sealing which will come to press in sealing contact on one shoulder 22 advantageously chamfer for this purpose.
  • One of the merits of one invention relates to the possibility of using a valve with total tightness, for example such as 26 for the second so-called safety valve 13 due to the absence of dynamic pressure at the right of the seat during closing. of the valve.
  • the means for slowing down the return stroke of the safety valve 13 takes the form in the example shown in the form of a composite upper mechanical connection 29 constituting a guided moving assembly.
  • This composite upper mechanical connection 29 consists of three free moving parts guided relative to one another. We distinguish the upper part formed by a push piston 30 mounted tight by a seal 31, push piston which moves along a chamber 32 open to one atmosphere by a vent 33 opening on one side of the block isolation 2.
  • the counterweight 34 of the composite mechanical link 29 comprises a seal 38 in the vicinity of its lower end providing the seal for this segment relative to the chamber 32 in which the push-piston 30 moves.
  • the upper moving part consists of a last segment 39 in the form of a rod secured to the body of the valve.
  • This rod 39 has an upper cylindrical end upwards, forming an end piston 40 sliding with play along the guide bore 35 formed in the insert 36.
  • This insert 36 laterally delimits with the isolation block 2 an annular chamber 41 through which the engine oil arrives which acts on the body of the safety valve 13.
  • the opposite ends of the counterweight 34 and the end piston 40 are separated by a space forming with the side wall of the guide bore a reservoir chamber 42 full of oil used as a shock absorbing pad.
  • the push-piston 30 actuates the safety valve 13 in opening by a downward movement of the motor from a control means, for example the force generated by the pressure of the working fluid of the reentry chamber 5 of the rod 7 of the jack which is exerted on the upper face of the plunger 30 placed in the supply duct of this reentry chamber.
  • a control means for example the force generated by the pressure of the working fluid of the reentry chamber 5 of the rod 7 of the jack which is exerted on the upper face of the plunger 30 placed in the supply duct of this reentry chamber.
  • the command to open the safety valve 13 can come from another means or from another driving source.
  • the damping effect results from the presence of oil contained in the reservoir chamber 42 forming a buffer and which will be gradually expelled from this reservoir chamber 42 during the return stroke of the safety valve 13 as a closing reminder.
  • the oil will be removed from this chamber by rolling along the end piston 40 because of the play existing between the latter and its guide bore 35.
  • the damping effect also results from the viscous friction of the valve stem in the oil.
  • This damping effect can be used in conjunction with a suitable distribution of the difference in stiffness of the valve return springs or with geometric variations in the hydraulic components. Either of these parameters can be used alone or in combination.
  • the airlock 9 communicates hydraulically through a channel 43 with a pressure sensitive sensor or detector 44, for example a pressure switch inserted in an electrical or electronic circuit whose electrical signal is used to signal a leak by a visual, audible or other.
  • FIG. 2 shows the mechanical block 45 of the pressure switch 44 and its two output pins 46 and 47 for its electrical connection with the operating circuit.
  • the actuation of the safety valve is ensured by any independent means, for example electromechanical, electromagnetic or any other means.
  • the holding device according to the invention is perfectly reversible with regard to the supply connections.
  • the outlet of the isolation block 2 can be connected to the reentry chamber 5 and conversely, the outlet chamber 6 can be connected directly to a pressure source.
  • the control at the output of the rod 7 of the jack is effected by sending, for example, a calibrated pressure to the hydraulic input 14 of the hydraulic block 8.
  • This driving pressure will automatically open the two valves one after the other. 13 and 11 against the restoring force of each of the springs 24 and 18 and will then supply the outlet chamber 6 of the rod.
  • the pressure will be cut off when the rod 7 of the jack reaches a desired outlet length.
  • the pressure is sent to the re-entry chamber 5. This arriving at the push-piston 30 1 'will actuate towards. the bottom, causing by displacement of the moving element the opening in series, one after the other, of the valves 13 then 11 in order to release the fluid out of the outlet chamber 6 through the airlock 9.
  • Figures 5 and 6 relate to a simplified variant of the device for holding in position a load according to the invention in which the general functions are preserved and implemented by the same means or equivalent means.
  • the device for holding in position applies mainly but not exclusively to a hydraulic cylinder 1 supporting a load carried by a support with a view to lifting and lowering it and keeping it securely in a given position.
  • the device for holding in position is a hydraulic isolation assembly 2 in the form of a hydraulic block 8 mounted between two branches 3 and 4 for supplying driving fluid respectively to the reentry chamber 5 and the outlet chamber 6 of its rod 7 in the case of a double-acting cylinder.
  • the hydraulic block 8 contains a chamber 9 comprising a lower orifice 10 with a primary non-return valve 11 in connection with the outlet chamber 6 and an upper orifice 12 provided with the non-return safety valve 13 in hydraulic communication with a hydraulic inlet 14 extended by a transverse channel 15.
  • the valves 11 and 13 are mounted passing from the top to the bottom of the figures.
  • the primary valve 11 has a ball 16 elastically returned to the closed position against its seat by a spring 18.
  • the safety valve 13 in the embodiment shown for this variant is of the type with a circular flat body 48 with a shoulder having a diameter less than that of its housing 49.
  • This fully sealed valve 13 ensures that the load is kept in position.
  • the clearance 25 existing between the lower end of the rod 23 and the ball 16 determines a degree of freedom of movement between the two valves and introduced into the commanded mode the delay in the opening of the primary valve 11 caused by the opening of the safety valve 13.
  • the security of holding in position is given by the valve 13.
  • the effectiveness of this safety valve depends on the holding of its seal after a large number of operations.
  • the slowing down function allowing delayed closure of the two valves can be obtained by different means taken individually or in combination, namely: the different stiffnesses of the two return springs of the valves, the viscous friction of the valve stem 13 in the chamber-airlock 9 and generally the damping of the rod in the oil and the shape and dimensions of the hydraulic components.
  • the modifications which result in changes of references are as follows.
  • the transverse channel 15 of the hydraulic inlet 14 has a bypass 53 towards a buffer chamber 54 located under the push piston 30.
  • this buffer chamber 54 no longer has communication with the outside via a vent. It is connected to inlet 14 and filled with pressurized oil. Consequently, the risk of corrosion which arose from its constant communication with the outside is completely eliminated.
  • the ascent of the push-piston 30 is guaranteed by a return spring 56.
  • Another advantage of this feature relates to the seal.
  • the sealing constraints are less important because the leaks feed the lines of the hydraulic circuit. The consequence is the possibility of removing the seal between the buffer chamber 54 and the arrival of the conduit 3 at the upper part of the push-piston 30 on the one hand and that which existed between the upper rod 40 of the check valve. security 13 and the buffer chamber 54 on the other hand.
  • This advantage further increases the reliability of the device.
  • the pressurized working fluid enters the hydraulic block 8 through the branches 15 and 53 towards the safety valve 13 and the buffer chamber 54.
  • This pressure is sufficient to first open the safety valve 13 and then the primary non-return valve 11 to feed the cylinder through its chamber 6 at the outlet of its rod 7.
  • the rod 7 rises with the load which it supports up to the level desired programmed or not. The pressure is then cut and the rod is immobilized in position. Immediately after immobilization, the charge causes an oil return for a short time.
  • the rapid oil return participates in the return movement of the ball of the primary valve 11 which comes to rest against its seat under the effect of the elastic restoring force.
  • the safety valve 13 then closes in the airlock chamber 9 in the absence of pressure due to the insulation resulting from the prior closure of the primary valve 11. This closure in the absence of dynamic pressure and therefore flow protects the seal of the safety valve and prevents it from coming out of its housing.
  • the delivery rate and the restoring force are sufficient for the ball 16 to close the primary valve 11 before the safety valve 13.
  • the safety of maintaining the load in position is guaranteed by the two non-return valves.
  • the primary ball valve 11 allows by its closure the immediate maintenance of the load.
  • Maintaining security is provided by the safety valve 13.
  • the seal provided by the safety valve is of high reliability.
  • the load will remain in position almost indefinitely.
  • the command to lower the rod 7 of the jack under load requires the opening of the two valves.
  • the force causing the opening is given by a control pressure. This can be the pressure exerted on the other chamber of the double-acting cylinder or an independent pressure for control or piloting.
  • the safety valve stem continues to descend.
  • the lower end of its rod 23 comes into thrust contact with the shutter element of the primary valve and by continuing its travel forces it to open.
  • the safety valve being in position open, its seal does not risk damage or exit from its housing.
  • valve opening control is no longer maintained and a delay in closing the safety valve 13 is caused in the same way as above. to the primary valve 11.
  • the retraction of the cylinder rod can also result from an otherwise controlled opening of the valves, that is to say independent of the driving pressure causing the retraction of the rod.
  • the device according to the invention can be oriented for mounting in the opposite direction to that shown in the figures or according to any other orientation of its support.

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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)
  • Fluid-Damping Devices (AREA)
  • Jigs For Machine Tools (AREA)
  • Gripping On Spindles (AREA)
  • Gripping Jigs, Holding Jigs, And Positioning Jigs (AREA)
  • Load-Engaging Elements For Cranes (AREA)

Abstract

The maintenance device consists of a hydraulic insulation unit (2) mounted between the supply circuits of a cylinder (1). The insulation unit (2) comprises a sluice (9) which has, at each of its two openings, an anti-return valve, one of which, the primary valve (11) is hydraulically connected to the outlet chamber (6) of the shaft (7) of the cylinder (1) and opens toward said chamber; and a safety valve (13) opening in the same direction, with the latter valve closing at a different rate than the primary valve closes. The invention is useful for maintaining the shaft of any cylinder in position, particularly a charged cylinder, and it is of interest to manufacturers of hydraulic devices, particularly lifting cylinders, as well as those who use them.

Description

DISPOSITIF DE MAINTIEN EN POSITION DE LA TIGE D'UN DEVICE FOR HOLDING THE ROD OF A
VERIN HYDRAULIQUEHYDRAULIC CYLINDER
La présente invention se rapporte à un dispositif de maintien en position de la tige d'un vérin hydraulique. Elle se rapporte accessoirement à la détection des fuites dans le circuit de retour de la chambre motrice.The present invention relates to a device for holding in position the rod of a hydraulic cylinder. It also relates to the detection of leaks in the return circuit of the motor chamber.
On utilise fréquemment des vérins hydrauliques comme organes moteurs dans les ensembles d'élévation et d'abaissement d'une structure porteuse. Ces ensembles sont bien connus et utilisés dans le domaine des transports, mais aussi dans le bâtiment et autres lieux sur lesquels les mouvements ' élévation et d'abaissement d'une charge sont quotidiens et nécessitent des efforts répétés et supérieurs à la force humaine.Hydraulic cylinders are frequently used as drive members in the lifting and lowering assemblies of a support structure. These assemblies are well known and used in the field of transport, but also in the building and other places on which the movements' raising and lowering of a load are daily and require repeated efforts and greater than human force.
On maintient classiquement un vérin sous charge par un clapet anti-retour inséré dans le circuit d'alimentation du vérin dans le sens passant vers la chambre de sortie de la tige. Cette fonction de maintien sous charge assure son rôle tant que 1 ' étanchéité du clapet peut être préservée. Celle-ci existe au départ en raison des contrôles de qualité effectués dans les ateliers de fabrication. Mais le clapet peut présenter progressivement ou soudainement un défaut d' étanchéité après une certaine période et ceci pour diverses raisons liées au fonctionnement ou au vieillissement, voire à un défaut mineur d'origine passé inaperçu. On peut mentionner, en tant que cause, un défaut géométrique par exemple de sphéricité de la bille, une impureté solide présente dans le circuit d'huile et venant s'immobiliser sur le siège du clapet ou toute autre cause d'un mauvais contact mécanique ou de surépaisseur locale entre le corps du clapet et son siège.A cylinder is conventionally maintained under load by a non-return valve inserted in the cylinder supply circuit in the direction passing towards the outlet chamber of the rod. This function of maintaining under load fulfills its role as long as the sealing of the valve can be preserved. This exists at the start because of the quality controls carried out in the manufacturing workshops. However, the valve may gradually or suddenly exhibit a leakage after a certain period of time, for various reasons linked to operation or aging, or even to a minor fault of origin which has gone unnoticed. We can mention, as a cause, a geometric defect, for example of sphericity of the ball, a solid impurity present in the oil circuit and coming to rest on the valve seat or any other cause of poor mechanical contact. or local allowance between the valve body and its seat.
Ce défaut engendre une fuite qui, même insignifiante peut provoquer après plusieurs heures de retenue un abaissement lent de la charge, dangereux pour les biens et les personnes situés en dessous.This defect gives rise to a leak which, even insignificant can cause after several hours of restraint a slow lowering of the load, dangerous for property and people located below.
Cette fonction de maintien s ' avère obligatoire dans tous les cas d'utilisation dans lesquels la sécurité du maintien en position de soutien représente une condition importante sinon primordiale.This holding function turns out to be compulsory in all use cases in which the safety of holding in the support position is an important if not essential condition.
Dans le cas de dispositifs hydrauliques, la garantie de retenue d ' une charge par un vérin hydraulique à l'aide d'un clapet anti-retour n'est apportée que par l' étanchéité de ce clapet.In the case of hydraulic devices, the guarantee that a load will be retained by a hydraulic cylinder using a non-return valve is only provided by the sealing of this valve.
Pour assurer sans défaillance une fonction aussi importante que la sécurité du maintien, le clapet doit présenter une garantie totale d ' étanchéité. Cette garantie totale ne peut exister et, pour cette raison, lorsque la sécurité l'exige, les vérins de levage sont associés à des dispositifs mécaniques de blocage-verrouillage par exemple des broches de verrouillage ou à des butées de sécurité. Ces dispositifs mécaniques de blocage- verrouillage ou de butée ont pour but d'assurer la sécurité du maintien en position des structures porteuses sous charge lors d ' un arrêt de fonctionnement prolongé. Ce maintien en position représente une mesure de sécurité pour les biens et les personnes que le vérin et son circuit de commande ne peuvent assurer seuls de façon infaillible en raison des fuites toujours possibles au niveau du clapet anti-retour.To ensure that a function as important as the safety of maintenance is maintained without fail, the valve must offer a total guarantee of watertightness. This total guarantee cannot exist and, for this reason, when security demands, the lifting cylinders are associated with mechanical blocking-locking devices, for example locking pins or with safety stops. The purpose of these mechanical blocking-locking or abutment devices is to ensure the safety of the load-bearing structures being held in position during a prolonged outage. This holding in position represents a safety measure for goods and people that the cylinder and its control circuit cannot ensure alone in an infallible manner due to the always possible leaks at the non-return valve.
L ' invention a pour but de se dispenser de l'utilisation de ces moyens mécaniques additionnels de retenue, nécessaires pour assurer la sécurité du maintien dans le cas d'un vérin hydraulique bloqué en position de retenue de la charge.The object of the invention is to dispense with the use of these additional mechanical retaining means, necessary to ensure the safety of the maintenance in the case of a hydraulic cylinder locked in the load retaining position.
A cet effet, l'invention se rapporte à un dispositif de maintien en position de la tige d'un vérin hydraulique au moins à simple effet comportant une chambre, par exemple de sortie de sa tige et au moins un clapet anti-retour monté dans le circuit d'alimentation de la chambre, passant vers cette chambre, le dispositif de maintien étant constitué d'un bloc hydraulique d'isolement à travers lequel est alimenté cette chambre caractérisé en ce que :To this end, the invention relates to a device for maintaining the position of the rod of an hydraulic cylinder at least with a single effect, comprising a chamber, for example from the output of its rod, and to the at least one non-return valve mounted in the chamber supply circuit, passing towards this chamber, the holding device consisting of a hydraulic isolation block through which this chamber is supplied, characterized in that:
. le clapet anti-retour dit clapet primaire est complété par un clapet anti-retour de sécurité séparé du clapet primaire et monté en amont dans le circuit d'alimentation de cette chambre, passant dans le même sens vers cette chambre,. the non-return valve called the primary valve is completed by a safety check valve separate from the primary valve and mounted upstream in the supply circuit of this chamber, passing in the same direction towards this chamber,
. un sas présentant à chacune de ses deux entrées- sorties un clapet anti-retour dont d'une part le clapet primaire placé le plus proche de cette chambre, et le clapet de sécurité, . des moyens de fermeture différée du clapet de sécurité par rapport à celle du clapet primaire, . un moyen de commande en ouverture des deux clapets.. an airlock presenting at each of its two inlets and outlets a non-return valve including, on the one hand, the primary valve placed closest to this chamber, and the safety valve,. means for deferred closing of the safety valve with respect to that of the primary valve,. a means for controlling the opening of the two valves.
L'invention trouve de multiples applications dans de nombreux domaines dès qu'il s'agit de levage- abaissement d'une charge avec maintien en position de retenue et plus particulièrement en position d'extension de la tige du vérin.The invention finds multiple applications in many fields when it comes to lifting-lowering a load with maintenance in the retaining position and more particularly in the extended position of the cylinder rod.
A titre d'exemple, on peut citer l'élévation de charges en vue du chargement d ' un véhicule de transport, l'élévation et le maintien de plate-formes ou de plateaux porteurs sur des véhicules de transport de voitures ou équivalents.By way of example, mention may be made of the lifting of loads with a view to loading a transport vehicle, the lifting and maintaining of platforms or load-bearing platforms on vehicles for transporting cars or the like.
Divers avantages découlent de l'utilisation du dispositif selon l'invention : . elle permet le verrouillage dans n'importe quelle position de la tige du vérin ; . le verrouillage est automatique ;Various advantages arise from the use of the device according to the invention:. it allows locking in any position of the cylinder rod; . locking is automatic;
. pour une fonction de verrouillage automatique, le dispositif hydraulique selon l'invention est peu onéreux ;. for an automatic locking function, the hydraulic device according to the invention is inexpensive;
. le dispositif hydraulique apporte une grande sécurité dans le maintien de la charge. D ' autres caractéristiques et avantages de l'invention apparaîtront dans la description qui suit, donnée à titre d'exemple et accompagnée des dessins dans lesquels : . la figure 1 est une vue générale schématique en coupe montrant le dispositif de maintien selon l'invention monté sur les branches d'alimentation d'un vérin ; . la figure 2 est une vue en coupe longitudinale d'une première réalisation du dispositif de maintien ; . les figures 3 et 4 sont respectivement des vues agrandies en coupe longitudinale de la partie centrale du dispositif de maintien dans le cas des deux variantes l'une à clapet conique et l'autre à clapet à étanchéité totale, avec clapets représentés à l'état fermé ;. the hydraulic device provides great security in maintaining the load. Other characteristics and advantages of the invention will appear in the description which follows, given by way of example and accompanied by the drawings in which: Figure 1 is a general schematic sectional view showing the holding device according to the invention mounted on the supply legs of a cylinder; . Figure 2 is a longitudinal sectional view of a first embodiment of the holding device; . Figures 3 and 4 are respectively enlarged views in longitudinal section of the central part of the holding device in the case of the two variants, one with conical valve and the other with fully sealed valve, with valves shown in the state closed ;
. la figure 5 est une vue générale schématique en coupe montrant la variante simplifiée du dispositif de maintien selon 1 ' invention montée sur les branches d'alimentation d'un vérin avec clapets représentés à 1 ' état fermé ;. Figure 5 is a general schematic sectional view showing the simplified variant of the holding device according to one invention mounted on the supply branches of a cylinder with valves shown in one closed state;
. la figure 6 est une vue en coupe longitudinale de la variante simplifiée du dispositif de maintien.. Figure 6 is a longitudinal sectional view of the simplified variant of the holding device.
Le dispositif de maintien en position de la tige d'un vérin hydraulique 1 se présente sous la forme d'un ensemble d'isolement 2 monté entre une branche 3 et une autre branche 4 d ' alimentation en fluide moteur respectivement d ' une chambre de rentrée 5 et d ' une chambre de sortie 6 d'une tige 7 du vérin hydrauliqueThe device for holding in position the rod of a hydraulic cylinder 1 is in the form of an isolation assembly 2 mounted between a branch 3 and another branch 4 for supplying working fluid respectively to a reentry 5 and an outlet chamber 6 of a rod 7 of the hydraulic cylinder
1. Cet ensemble d'isolement 2 forme un bloc hydraulique 8 renfermant une chambre-sas 9 appelée pour des raisons de commodité simplement sas. Ce sas présente un orifice inférieur 10 pourvu d'un clapet anti-retour primaire 11 en liaison hydraulique avec la chambre de sortie 6 de la tige 7 du vérin et en regard, un orifice supérieur 12 pourvu d'un clapet anti-retour de sécurité 13 en communication hydraulique avec une entrée hydraulique 14 prolongée par un canal transversal 15 d'alimentation en fluide moteur de la chambre de sortie 6 à partir de 1 ' entrée hydraulique 14. Les clapets anti-retour primaire 11 et de sécurité 13 sont distincts physiquement et montés passants dans le sens du haut vers le bas des figures, c'est-à-dire dans le sens d'alimentation de la chambre de sortie 6 de la tige 7 à partir de l'arrivée hydraulique 14.1. This isolation assembly 2 forms a hydraulic block 8 containing a chamber-lock 9 called for reasons of convenience simply lock. This airlock has a lower orifice 10 provided with a primary non-return valve 11 in hydraulic connection with the outlet chamber 6 of the rod 7 of the jack and opposite, an upper orifice 12 provided with a safety non-return valve 13 in hydraulic communication with a hydraulic inlet 14 extended by a transverse channel 15 for supplying motive fluid to the outlet chamber 6 from the hydraulic inlet 14. The primary non-return 11 and safety check valves 13 are physically separate and mounted pass-through in the direction from the top to the bottom of the figures, that is to say in the direction of supply of the outlet chamber 6 of the rod 7 from the hydraulic inlet 14.
De façon avantageuse, le clapet primaire 11 est réalisé sous la forme d'un clapet anti-retour à bille 16 forcée en rappel de fermeture contre un siège de forme adaptée par exemple conique 17 traversé en son centre par l'orifice inférieur 10. La force de rappel est engendrée par un ressort de rappel 18 emprisonné dans un logement 19 au niveau de l'extrémité inférieure du bloc d'isolement 2.Advantageously, the primary valve 11 is produced in the form of a non-return ball valve 16 forced into a closing reminder against a seat of suitable shape, for example conical 17 traversed in its center by the lower orifice 10. The return force is generated by a return spring 18 trapped in a housing 19 at the lower end of the isolation block 2.
Le clapet anti-retour de sécurité 13 est réalisé selon une première variante sous la forme d ' un corps tronconique 20 à surface conique active en contact en position de fermeture avec un rebord circulaire 21 d'un épaulement annulaire 22 traversé en son centre par l'orifice supérieur 12. Le clapet de sécurité 13 s'ouvre classiquement et automatiquement par la pression incidente.The safety check valve 13 is produced in a first variant in the form of a frustoconical body 20 with an active conical surface in contact in the closed position with a circular rim 21 of an annular shoulder 22 traversed in its center by the 'upper orifice 12. The safety valve 13 opens conventionally and automatically by the incident pressure.
L'ouverture du clapet de sécurité 13 peut être commandée par un moyen extérieur au bloc d ' isolement 2 par exemple par la force motrice du fluide hydraulique sous pression alimentant la chambre de rentrée de la tige ou tout autre moyen. Elle provoque en plus en cascade 1 ' ouverture commandée du clapet primaire 11. Pour ce faire, le clapet de sécurité 13 se prolonge vers le bas par une tige inférieure de commande 23 qui porte, enfilé sur sa surface latérale, un ressort de rappel 24 en position de fermeture. Cette tige de commande 23 se termine par une extrémité libre à front droit de poussée qui peut traverser l'orifice inférieur 10 du sas 9 pour déplacer par poussée le corps du clapet primaire 11 en ouverture, c'est-à-dire en éloignement de son siège 17 à l' encontre de la force élastique de rappel fournie par le ressort 18.The opening of the safety valve 13 can be controlled by a means external to the isolation block 2, for example by the driving force of the hydraulic fluid under pressure supplying the re-entry chamber of the rod or any other means. It also causes the controlled opening of the primary valve 11 to be cascaded. To do this, the safety valve 13 is extended downwards by a lower control rod 23 which carries, threaded on its lateral surface, a return spring 24 in the closed position. This control rod 23 ends with a free end with a straight thrust front which can pass through the lower orifice 10 of the airlock 9 to move by pushing the body of the primary valve 11 when opening, that is to say away from its seat 17 against the elastic return force provided by the spring 18.
S ' agissant de deux pièces séparées, il existe un jeu 25 entre l'extrémité de la tige 23 et la bille 16 du clapet primaire 11 et donc une indépendance de mouvement entre les deux clapets .Being two separate parts, there is a clearance 25 between the end of the rod 23 and the ball 16 of the primary valve 11 and therefore independence of movement between the two valves.
Le clapet de sécurité 13 est solidaire d'un moyen de ralentissement de sa course en rappel de fermeture afin de différer sa fermeture par rapport à celle du clapet primaire 11. On peut ainsi garantir 1 * absence de pression dynamique importante et donc de débit dans le sas 9 pendant la phase de fermeture du clapet de sécurité 13.The safety valve 13 is integral with a means of slowing down its stroke in closing reminder so as to delay its closing with respect to that of the primary valve 11. This can thus guarantee 1 * absence of significant dynamic pressure and therefore of flow in the airlock 9 during the closing phase of the safety valve 13.
Cette caractéristique permet notamment d'envisager l'utilisation d'un joint pour parfaire 1' étanchéité et accroître ainsi l'efficacité du clapet de sécurité. Ce type de clapet avec joint sera appelé clapet à étanchéité totale 26. Il constitue le moyen idéal de fermeture du sas 9 et de garantie renforcée du maintien en position sous charge de la tige du vérin. Cette variante est représentée sur la figure 4 sous la forme d'un clapet à étanchéité totale 26 à joint 27 par exemple torique reposant sur un siège en forme de gorge 28. Ces clapets à étanchéité totale sont peu résistants à une pression dynamique en raison des risques d'extrusion du joint qu'elle peut provoquer.This characteristic makes it possible in particular to envisage the use of a seal to perfect the seal and thus increase the efficiency of the safety valve. This type of valve with seal will be called a fully sealed valve 26. It constitutes the ideal means of closing the airlock 9 and of enhanced guarantee of the position held under load of the cylinder rod. This variant is represented in FIG. 4 in the form of a fully sealed valve 26 with a seal 27, for example an O-ring resting on a groove-shaped seat 28. These fully sealed valves are not very resistant to dynamic pressure due to the risks of extrusion of the seal that it can cause.
Pour un autre exemple de réalisation d'un clapet à étanchéité totale on pourra envisager que la surface conique du corps du clapet de sécurité 13 représenté sur la figure 3, soit partiellement ou totalement garnie d'un revêtement ou d'un joint d' étanchéité qui viendra se presser en contact d' étanchéité sur 1 ' épaulement 22 avantageusement chanfreine à cet effet.For another exemplary embodiment of a valve with total tightness, it may be envisaged that the conical surface of the body of the safety valve 13 shown in FIG. 3 is either partially or completely lined with a coating or a seal. sealing which will come to press in sealing contact on one shoulder 22 advantageously chamfer for this purpose.
Un des mérites de 1 ' invention concerne la possibilité d'utilisation d'un clapet à étanchéité totale par exemple tel que 26 pour le deuxième clapet dit de sécurité 13 en raison de l'absence de pression dynamique au droit du siège lors de la fermeture du clapet. Le moyen de ralentissement de la course retour du clapet de sécurité 13 se matérialise dans l'exemple représenté sous la forme d'une liaison mécanique supérieure composite 29 constituant un équipage mobile guidé. Cette liaison mécanique supérieure composite 29 se compose de trois parties libres en mouvement guidées les unes par rapport aux autres. On distingue la partie supérieure formée d'un piston-poussoir 30 monté étanche par un joint 31, piston-poussoir qui se déplace le long d'une chambre 32 ouverte à 1 ' atmosphère par un évent 33 débouchant sur une face du bloc d ' isolement 2.One of the merits of one invention relates to the possibility of using a valve with total tightness, for example such as 26 for the second so-called safety valve 13 due to the absence of dynamic pressure at the right of the seat during closing. of the valve. The means for slowing down the return stroke of the safety valve 13 takes the form in the example shown in the form of a composite upper mechanical connection 29 constituting a guided moving assembly. This composite upper mechanical connection 29 consists of three free moving parts guided relative to one another. We distinguish the upper part formed by a push piston 30 mounted tight by a seal 31, push piston which moves along a chamber 32 open to one atmosphere by a vent 33 opening on one side of the block isolation 2.
On remarque ensuite une masselotte 34 libre en coulissement dans un alésage-guide 35 prévu dans une pièce rapportée 36. L'extrémité supérieure 37 de cette masselotte 34 est en contact avec la face inférieure du piston-poussoir 30.There is then a counterweight 34 which is free to slide in a guide bore 35 provided in an insert 36. The upper end 37 of this counterweight 34 is in contact with the underside of the push-piston 30.
La masselotte 34 de la liaison mécanique composite 29 comporte un joint d' étanchéité 38 au voisinage de son extrémité inférieure réalisant 1' étanchéité de ce segment par rapport à la chambre 32 dans laquelle se déplace le piston-poussoir 30.The counterweight 34 of the composite mechanical link 29 comprises a seal 38 in the vicinity of its lower end providing the seal for this segment relative to the chamber 32 in which the push-piston 30 moves.
L'équipage mobile supérieur se compose d'un dernier segment 39 en forme de tige solidaire du corps du clapet. Cette tige 39 présente vers le haut une extrémité supérieure de forme cylindrique formant un piston d'extrémité 40 coulissant avec jeu le long de l'alésage-guide 35 formé dans la pièce rapportée 36. Cette pièce rapportée 36 délimite latéralement avec le bloc d'isolement 2 une chambre annulaire 41 par laquelle arrive l'huile moteur qui agit sur le corps du clapet de sécurité 13. Les extrémités en regard de la masselotte 34 et du piston d'extrémité 40 sont séparées par un espace formant avec la paroi latérale de 1 ' alésage-guide une chambre-réservoir 42 pleine d'huile utilisée comme tampon amortisseur. Le piston-poussoir 30 actionne en ouverture le clapet de sécurité 13 par un déplacement moteur vers le bas provenant d'un moyen de commande par exemple la force engendrée par la pression du fluide moteur de la chambre de rentrée 5 de la tige 7 du vérin qui s ' exerce sur la face supérieure du piston-poussoir 30 placée dans le conduit d ' alimentation de cette chambre de rentrée.The upper moving part consists of a last segment 39 in the form of a rod secured to the body of the valve. This rod 39 has an upper cylindrical end upwards, forming an end piston 40 sliding with play along the guide bore 35 formed in the insert 36. This insert 36 laterally delimits with the isolation block 2 an annular chamber 41 through which the engine oil arrives which acts on the body of the safety valve 13. The opposite ends of the counterweight 34 and the end piston 40 are separated by a space forming with the side wall of the guide bore a reservoir chamber 42 full of oil used as a shock absorbing pad. The push-piston 30 actuates the safety valve 13 in opening by a downward movement of the motor from a control means, for example the force generated by the pressure of the working fluid of the reentry chamber 5 of the rod 7 of the jack which is exerted on the upper face of the plunger 30 placed in the supply duct of this reentry chamber.
La commande en ouverture du clapet de sécurité 13 peut provenir d'un autre moyen ou d'une autre source motrice.The command to open the safety valve 13 can come from another means or from another driving source.
L'effet amortisseur résulte de la présence d'huile contenu dans la chambre-réservoir 42 formant tampon et qui sera expulsée progressivement hors de cette chambre-réservoir 42 lors de la course retour du clapet de sécurité 13 en rappel de fermeture. En effet, l'huile va être chassée de cette chambre par laminage le long du piston d'extrémité 40 en raison du jeu existant entre celui-ci et son alésage-guide 35.The damping effect results from the presence of oil contained in the reservoir chamber 42 forming a buffer and which will be gradually expelled from this reservoir chamber 42 during the return stroke of the safety valve 13 as a closing reminder. In effect, the oil will be removed from this chamber by rolling along the end piston 40 because of the play existing between the latter and its guide bore 35.
L'effet amortisseur résulte également du frottement visqueux de la tige du clapet de sécurité dans l'huile. Cet effet amortisseur peut être utilisé conjointement avec une répartition adaptée de la différence de raideur des ressorts de rappel des clapets ou avec des variations géométriques des composants hydrauliques. L'un ou l'autre de ces paramètres peut être utilisé isolément ou en combinaison. Le sas 9 communique hydrauliquement par un canal 43 avec un capteur ou un détecteur 44 sensible à la pression, par exemple un manocontact inséré dans un circuit électrique ou électronique dont le signal électrique est exploité pour signaler une fuite par un moyen avertisseur visuel, sonore ou autre.The damping effect also results from the viscous friction of the valve stem in the oil. This damping effect can be used in conjunction with a suitable distribution of the difference in stiffness of the valve return springs or with geometric variations in the hydraulic components. Either of these parameters can be used alone or in combination. The airlock 9 communicates hydraulically through a channel 43 with a pressure sensitive sensor or detector 44, for example a pressure switch inserted in an electrical or electronic circuit whose electrical signal is used to signal a leak by a visual, audible or other.
On a représenté sur la figure 2 le bloc mécanique 45 du manocontact 44 et ses deux broches de sortie 46 et 47 pour son raccordement électrique avec le circuit d'exploitation.FIG. 2 shows the mechanical block 45 of the pressure switch 44 and its two output pins 46 and 47 for its electrical connection with the operating circuit.
Dans le cas d ' un vérin hydraulique à simple effet, 1 ' actionnement du clapet de sécurité est assuré par un moyen quelconque indépendant, par exemple électromécanique, électromagnétique ou tout autre moyen.In the case of a single-acting hydraulic cylinder, the actuation of the safety valve is ensured by any independent means, for example electromechanical, electromagnetic or any other means.
Par ailleurs, le dispositif de maintien selon 1 ' invention est parfaitement réversible en ce qui concerne les branchements d'alimentation. Ainsi, la sortie du bloc d'isolement 2 peut être reliée à la chambre de rentrée 5 et inversement, la chambre de sortie 6 peut être reliée directement à une source de pression.Furthermore, the holding device according to the invention is perfectly reversible with regard to the supply connections. Thus, the outlet of the isolation block 2 can be connected to the reentry chamber 5 and conversely, the outlet chamber 6 can be connected directly to a pressure source.
On expliquera tout d'abord le fonctionnement du vérin 1 en déplacement de sa tige 7 pour des besoins de levage ou d'abaissement, puis le fonctionnement du bloc d ' isolement 2 en maintien de position sous charge correspondant à la hauteur d'élévation souhaitée.We will first explain the operation of the cylinder 1 in displacement of its rod 7 for lifting or lowering needs, then the operation of the isolation block 2 in position maintenance under load corresponding to the desired elevation height .
La commande en sortie de la tige 7 du vérin s'effectue par l'envoi par exemple d'une pression calibrée à l'entrée hydraulique 14 du bloc hydraulique 8. Cette pression motrice ouvrira automatiquement 1 ' un après l'autre les deux clapets 13 et 11 à l' encontre de la force de rappel de chacun des ressorts 24 et 18 et viendra ensuite alimenter la chambre de sortie 6 de la tige. On coupera la pression lorsque la tige 7 du vérin atteindra une longueur de sortie voulue.The control at the output of the rod 7 of the jack is effected by sending, for example, a calibrated pressure to the hydraulic input 14 of the hydraulic block 8. This driving pressure will automatically open the two valves one after the other. 13 and 11 against the restoring force of each of the springs 24 and 18 and will then supply the outlet chamber 6 of the rod. The pressure will be cut off when the rod 7 of the jack reaches a desired outlet length.
Aussitôt la pression coupée, les forces de rappel des ressorts 18 et 24 jusque là dépassées par la force engendrée par la pression motrice, tendent à repousser les clapets 11 et 13 en position de fermeture. L'amortissement du clapet de sécurité produira son effet en vue de garantir le retard souhaité entre les fermetures des deux clapets c'est-à- dire la fermeture différée du clapet de sécurité 13 par rapport à celle du clapet primaire 11. La pression relative dans le sas sera alors sensiblement nulle.As soon as the pressure is cut, the forces of recall of the springs 18 and 24 hitherto exceeded by the force generated by the driving pressure, tend to push the valves 11 and 13 into the closed position. The damping of the safety valve will have its effect in order to guarantee the desired delay between the closings of the two valves, that is to say the delayed closure of the safety valve 13 relative to that of the primary valve 11. The relative pressure in the airlock will then be substantially zero.
Lors d'une fuite éventuelle du clapet primaire 11, qui ne peut se produire pour des raisons mécaniques qu'au moment de la fermeture de ce clapet, la pression statique régnant dans le sas deviendra rapidement supérieure au seuil de calibrage du manocontact 44 et déclenchera l'alerte.During a possible leak of the primary valve 11, which can only occur for mechanical reasons when the valve is closed, the static pressure prevailing in the airlock will quickly become greater than the calibration threshold of the pressure switch 44 and will trigger the alert.
Cette augmentation de pression atteindra vite une valeur d'équilibre correspondant à la neutralisation du débit de fuite car le clapet de sécurité 13 assure alors l' étanchéité à lui seul.This increase in pressure will quickly reach an equilibrium value corresponding to the neutralization of the leakage rate because the safety valve 13 then ensures sealing on its own.
Pour actionner la tige du vérin en rentrée, on envoie la pression dans la chambre de rentrée 5. Celle-ci arrivant au piston-poussoir 30 1 ' actionnera vers . le bas, provoquant par déplacement de l'équipage mobile l'ouverture en série, l'un après l'autre, des clapets 13 puis 11 afin de libérer le fluide hors de la chambre de sortie 6 à travers le sas 9.To actuate the rod of the re-entry cylinder, the pressure is sent to the re-entry chamber 5. This arriving at the push-piston 30 1 'will actuate towards. the bottom, causing by displacement of the moving element the opening in series, one after the other, of the valves 13 then 11 in order to release the fluid out of the outlet chamber 6 through the airlock 9.
Les figures 5 et 6 se rapportent à une variante simplifiée du dispositif de maintien en position d'une charge selon l'invention dans laquelle les fonctions générales sont conservées et mises en oeuvre par les mêmes moyens ou des moyens équivalents.Figures 5 and 6 relate to a simplified variant of the device for holding in position a load according to the invention in which the general functions are preserved and implemented by the same means or equivalent means.
La surveillance de la pression dans la chambre-sas 9 s'est avérée non indispensable. Par ailleurs, la chambre située sous le piston-poussoir 30 ne communique plus avec l'extérieur, mais avec 1 ' arrivée du fluide moteur de montée de la tige 7 du vérin hydraulique.Monitoring the pressure in the airlock chamber 9 has proven to be non-essential. Furthermore, the chamber located under the push piston 30 no longer communicates with the outside, but with the arrival of the engine fluid raising the rod 7 of the hydraulic cylinder.
Les éléments et organes principaux restent maintenus fonctionnellement identiques et comportent en général les mêmes références. Pour la commodité du lecteur, il est apparu souhaitable de redonner ci-après une brève description d'ensemble.The main elements and organs remain functionally identical and generally have the same references. For the convenience of the reader, it appeared desirable to give a brief overall description below.
Le dispositif de maintien en position selon 1 ' invention s ' applique principalement mais non exclusivement à un vérin hydraulique 1 soutenant une charge portée par un support en vue de son levage et abaissement et de son maintien en toute sécurité dans une position donnée.The device for holding in position according to the invention applies mainly but not exclusively to a hydraulic cylinder 1 supporting a load carried by a support with a view to lifting and lowering it and keeping it securely in a given position.
Le dispositif de maintien en position est un ensemble hydraulique d'isolement 2 sous la forme d'un bloc hydraulique 8 monté entre deux branches 3 et 4 d ' alimentation en fluide moteur respectivement de la chambre de rentrée 5 et la chambre de sortie 6 de sa tige 7 dans le cas d'un vérin à double effet. Le bloc hydraulique 8 renferme une chambre- sas 9 comportant un orifice inférieur 10 à clapet antiretour primaire 11 en liaison avec la chambre de sortie 6 et un orifice supérieur 12 pourvu du clapet antiretour de sécurité 13 en communication hydraulique avec une entrée hydraulique 14 prolongée par un canal transversal 15. Les clapets 11 et 13 sont montés passants du haut vers le bas des figures.The device for holding in position is a hydraulic isolation assembly 2 in the form of a hydraulic block 8 mounted between two branches 3 and 4 for supplying driving fluid respectively to the reentry chamber 5 and the outlet chamber 6 of its rod 7 in the case of a double-acting cylinder. The hydraulic block 8 contains a chamber 9 comprising a lower orifice 10 with a primary non-return valve 11 in connection with the outlet chamber 6 and an upper orifice 12 provided with the non-return safety valve 13 in hydraulic communication with a hydraulic inlet 14 extended by a transverse channel 15. The valves 11 and 13 are mounted passing from the top to the bottom of the figures.
Dans la réalisation représentée, le clapet primaire 11 est à bille 16 rappelée élastiquement en position de fermeture contre son siège par un ressort 18.In the embodiment shown, the primary valve 11 has a ball 16 elastically returned to the closed position against its seat by a spring 18.
Le clapet de sécurité 13 dans la réalisation représentée pour cette variante est du type à corps plat 48 circulaire à épaulement de diamètre inférieur à celui de son logement 49.The safety valve 13 in the embodiment shown for this variant is of the type with a circular flat body 48 with a shoulder having a diameter less than that of its housing 49.
Il comporte une gorge annulaire 50 dans laquelle est logé un joint d' étanchéité 51 par exemple torique. Il est rappelé élastiquement en position de fermeture contre son siège par un ressort coaxial 52 de rappel monté sur la naissance de la tige de commande 23 dont l'extrémité inférieure peut traverser l'orifice inférieur 10 en vue d'une action mécanique de poussée sur la bille 16.It comprises an annular groove 50 in which is housed a seal 51 for example toric. It is resiliently returned to the closed position against its seat by a coaxial return spring 52 mounted on the birth of the control rod 23, the lower end of which can pass through the lower orifice 10 for mechanical thrust action on the ball 16.
Ce clapet 13 à étanchéité totale permet de garantir le maintien en position de la charge.This fully sealed valve 13 ensures that the load is kept in position.
Comme déjà indiqué, le jeu 25 existant entre l'extrémité inférieure de la tige 23 et la bille 16 détermine un degré de liberté de mouvement entre les deux clapets et introduit dans le mode commandé le retard à l'ouverture du clapet primaire 11 provoquée par l'ouverture du clapet de sécurité 13. La sécurité du maintien en position est donnée par le clapet 13. Cependant, l'efficacité de ce clapet de sécurité dépend de la tenue de son joint après un nombre important de manoeuvres.As already indicated, the clearance 25 existing between the lower end of the rod 23 and the ball 16 determines a degree of freedom of movement between the two valves and introduced into the commanded mode the delay in the opening of the primary valve 11 caused by the opening of the safety valve 13. The security of holding in position is given by the valve 13. However, the effectiveness of this safety valve depends on the holding of its seal after a large number of operations.
La fiabilité de ce joint résulte de la fermeture du clapet sous débit faible et de préférence quasi nul.The reliability of this seal results from the closure of the valve under low flow and preferably almost zero.
Ces conditions sont réalisées si 1 ' on peut assurer dans tous les cas la fermeture postérieure du clapet de sécurité 13 par rapport au clapet primaire 11.These conditions are fulfilled if one can in any case ensure the posterior closure of the safety valve 13 relative to the primary valve 11.
Cette caractéristique résultait dans les variantes ci-dessus notamment d'un ralentissement approprié à la fermeture du clapet de sécurité 13 par un moyen de ralentissement qui consistait à fractionner l'équipage supérieur mobile en une masselotte 34 libre en coulissement axial dont l'extrémité supérieure était en contact avec la base d'un piston-poussoir 30 se déplaçant le long d'une chambre 32 ouverte à 1 ' atmosphère. L'extrémité inférieure de la masselotte 34 se trouvait en regard de l'extrémité d'un piston 40 solidaire du corps du clapet à travers une chambre- réservoir 42 remplie d'huile utilisée comme tampon amortisseur.This characteristic resulted in the above variants in particular from a slowing down suitable for closing the safety valve 13 by a slowing down means which consisted in dividing the mobile upper assembly into a counterweight 34 free in axial sliding, the upper end of which was in contact with the base of a push piston 30 moving along a chamber 32 open to the atmosphere. The lower end of the counterweight 34 was opposite the end of a piston 40 secured to the body of the valve through a chamber tank 42 filled with oil used as a shock absorber buffer.
Dans la variante présentement décrite et représentée sur les figures 5 et 6, il n'existe plus de masselotte 34 constituant un intermédiaire mécanique mobile entre la clapet de sécurité 13 et le piston- poussoir 30 d ' actionnement .In the variant presently described and shown in FIGS. 5 and 6, there no longer exists a counterweight 34 constituting a movable mechanical intermediate between the safety valve 13 and the actuating piston 30.
Comme dans les variantes précédentes, la fonction de ralentissement permettant une fermeture différée des deux clapets peut être obtenue par différents moyens pris isolément ou en combinaison à savoir : les raideurs différentes des deux ressorts de rappel des clapets, le frottement visqueux de la tige du clapet 13 dans la chambre-sas 9 et de façon générale l'amortissement de la tige dans l'huile et la conformation et les dimensions des composants hydrauliques .As in the previous variants, the slowing down function allowing delayed closure of the two valves can be obtained by different means taken individually or in combination, namely: the different stiffnesses of the two return springs of the valves, the viscous friction of the valve stem 13 in the chamber-airlock 9 and generally the damping of the rod in the oil and the shape and dimensions of the hydraulic components.
Les modifications qui se traduisent par des changements de références sont les suivantes. Le canal transversal 15 de l'entrée hydraulique 14 présente une dérivation 53 vers une chambre-tampon 54 située sous le piston-poussoir 30. De ce fait, cette chambre-tampon 54 ne possède plus de communication avec l'extérieur par un évent. Elle est reliée à l'entrée 14 et remplie d'huile sous pression. En conséquence le risque de corrosion qui provenait de sa communication constante avec l'extérieur est totalement éliminé.The modifications which result in changes of references are as follows. The transverse channel 15 of the hydraulic inlet 14 has a bypass 53 towards a buffer chamber 54 located under the push piston 30. As a result, this buffer chamber 54 no longer has communication with the outside via a vent. It is connected to inlet 14 and filled with pressurized oil. Consequently, the risk of corrosion which arose from its constant communication with the outside is completely eliminated.
Lors de la commande en descente de la tige du piston du vérin par le conduit 3, l'entrée 14 provenant de la ligne d'alimentation 55 de la chambre 6 du vérin à travers le dispositif selon 1 ' invention se trouve reliée à la bâche en même temps que la chambre-tampon 54. Le déplacement commandé du piston-poussoir 30 vers le bas par la pression du fluide venant du conduit 3, provoque 1 ' ouverture du clapet de sécurité 13 puis consécutivement, par exemple par la tige 23, après contact mécanique de poussée celle du clapet primaire 11.When the piston rod of the jack is lowered by the conduit 3, the inlet 14 coming from the supply line 55 of the chamber 6 of the jack through the device according to the invention is connected to the cover at the same time as the buffer chamber 54. The controlled movement of the push piston 30 downwards by the pressure of the fluid coming from the conduit 3, causes the safety valve 13 to open, then consecutively, for example by the rod 23, after mechanical thrust contact that of the primary valve 11.
La remontée du piston-poussoir 30 est garantie par un ressort de rappel 56. Un autre avantage de cette particularité concerne 1 ' étanchéité. Les contraintes d' étanchéité sont moins importantes car les fuites alimentent les ligne du circuit hydraulique. La conséquence en est la possibilité de suppression de 1 ' étanchéité entre la chambre-tampon 54 et l'arrivée du conduit 3 à la partie supérieure du piston-poussoir 30 d'une part et celle qui existait entre la tige supérieure 40 du clapet de sécurité 13 et la chambre-tampon 54 d'autre part.The ascent of the push-piston 30 is guaranteed by a return spring 56. Another advantage of this feature relates to the seal. The sealing constraints are less important because the leaks feed the lines of the hydraulic circuit. The consequence is the possibility of removing the seal between the buffer chamber 54 and the arrival of the conduit 3 at the upper part of the push-piston 30 on the one hand and that which existed between the upper rod 40 of the check valve. security 13 and the buffer chamber 54 on the other hand.
Cet avantage augmente encore la fiabilité du dispositif.This advantage further increases the reliability of the device.
On expliquera ci-dessous le fonctionnement du dispositif de maintien selon l'invention en prenant comme exemple un vérin sous charge. Le fonctionnement sans charge se transpose aisément à partir de celui décrit.The operation of the holding device according to the invention will be explained below by taking a jack under load as an example. Operation without load is easily transposed from that described.
Montée de la tige du vérin sous charge :Rise of the cylinder rod under load:
Le fluide moteur sous pression pénètre dans le bloc hydraulique 8 par les branches 15 et 53 vers le clapet de sécurité 13 et la chambre-tampon 54.The pressurized working fluid enters the hydraulic block 8 through the branches 15 and 53 towards the safety valve 13 and the buffer chamber 54.
Cette pression suffit à ouvrir en premier le clapet de sécurité 13 puis le clapet anti-retour primaire 11 pour alimenter le vérin par sa chambre 6 de sortie de sa tige 7. La tige 7 monte avec la charge qu ' elle supporte jusqu'au niveau souhaité programmé ou non. La pression est alors coupée et la tige s ' immobilise en position. Immédiatement après l'immobilisation, la charge provoque un retour d'huile pendant un temps court.This pressure is sufficient to first open the safety valve 13 and then the primary non-return valve 11 to feed the cylinder through its chamber 6 at the outlet of its rod 7. The rod 7 rises with the load which it supports up to the level desired programmed or not. The pressure is then cut and the rod is immobilized in position. Immediately after immobilization, the charge causes an oil return for a short time.
Le retour rapide d'huile participe au mouvement de retour de la bille du clapet primaire 11 qui vient s ' appliquer contre son siège sous 1 ' effet de la force de rappel élastique.The rapid oil return participates in the return movement of the ball of the primary valve 11 which comes to rest against its seat under the effect of the elastic restoring force.
Dans le cas d'absence de charge, le clapet primaire 11 se ferme sous le seul effet de la force de rappel du ressort.In the case of no load, the primary valve 11 closes under the sole effect of the return force of the spring.
Le clapet de sécurité 13 se ferme dans un deuxième temps dans la chambre-sas 9 en l'absence de pression en raison de 1 ' isolation provenant de la fermeture préalable du clapet primaire 11. Cette fermeture en 1 ' absence de pression dynamique et donc de débit ménage le joint du clapet de sécurité et évite à celui-ci de sortir de son logement.The safety valve 13 then closes in the airlock chamber 9 in the absence of pressure due to the insulation resulting from the prior closure of the primary valve 11. This closure in the absence of dynamic pressure and therefore flow protects the seal of the safety valve and prevents it from coming out of its housing.
Pour garantir cette succession ordonnée des fermetures, on peut jouer sur les différents facteurs déjà mentionnés ci-dessus à savoir : les raideurs différentes des deux ressorts de rappel des clapets, le frottement visqueux de la tige du clapet 13 dans la chambre-sas 9 et de façon générale l'amortissement de la tige dans l'huile et la conformation et les dimensions des composants hydrauliques.To guarantee this ordered succession of closings, one can play on the various factors already mentioned above, namely: the different stiffnesses of the two return springs of the valves, the viscous friction of the valve stem 13 in the chamber-airlock 9 and generally the damping of the rod in oil and the shape and dimensions of the hydraulic components.
Dans la majorité des cas de montée de la tige sous charge, le débit de refoulement et la force de rappel sont suffisants pour que la bille 16 ferme le clapet primaire 11 avant le clapet de sécurité 13.In most cases where the rod is mounted under load, the delivery rate and the restoring force are sufficient for the ball 16 to close the primary valve 11 before the safety valve 13.
Maintien en position de la chargeMaintaining the load position
La sécurité du maintien de la charge en position est garantie par les deux clapets anti-retour. Le clapet primaire 11 à bille 16 permet par sa fermeture le maintien immédiat de la charge.The safety of maintaining the load in position is guaranteed by the two non-return valves. The primary ball valve 11 allows by its closure the immediate maintenance of the load.
En fonctionnement normal la pression dans la chambre-sas 9 est faible.In normal operation the pressure in the airlock chamber 9 is low.
En cas de défection ou de fuite du clapet primaire 11, si petite soit-elle, le maintien par ce seul clapet n'est plus garanti dans le temps. Cette dérive conduirait à un abaissement non volontaire de la charge, lent mais dangereux pour le chargement situé en dessous de la plate-forme maintenue par le vérin.In the event of defection or leakage of the primary valve 11, however small it may be, maintenance by this single valve is no longer guaranteed over time. This drift would lead to an involuntary lowering of the load, slow but dangerous for loading located below the platform held by the jack.
La sécurité du maintien est apportée par le clapet de sécurité 13. Réalisé avec un joint 51 non soumis au moment de sa fermeture à un débit important préjudiciable à sa tenue, l' étanchéité procurée par le clapet de sécurité est de haute fiabilité.Maintaining security is provided by the safety valve 13. Produced with a seal 51 which is not subjected at the time of its closure to a significant flow rate detrimental to its performance, the seal provided by the safety valve is of high reliability.
La charge restera en position pratiquement indéfiniment.The load will remain in position almost indefinitely.
Descente de la tige sous charge :Lowering the rod under load:
La commande de descente de la tige 7 du vérin sous charge nécessite l'ouverture des deux clapets. La force provoquant 1 ' ouverture est donnée par une pression de commande. Celle-ci peut être la pression s 'exerçant sur l'autre chambre du vérin à double effet ou une pression indépendante de commande ou de pilotage.The command to lower the rod 7 of the jack under load requires the opening of the two valves. The force causing the opening is given by a control pressure. This can be the pressure exerted on the other chamber of the double-acting cylinder or an independent pressure for control or piloting.
Elle s'exerce d'abord sur le piston-poussoir 30 dont le déplacement engendre celui du corps du clapet par contact du piston-poussoir 30 avec 1 ' extrémité de la prolongation supérieure 40 de la tige du clapet de sécurité 13 et par poussée mécanique de translation.It is exerted first on the push-piston 30 whose displacement generates that of the valve body by contact of the push-piston 30 with the end of the upper extension 40 of the stem of the safety valve 13 and by mechanical push of translation.
La tige du clapet de sécurité continue à descendre. L'extrémité inférieure de sa tige 23 arrive en contact de poussée avec 1 ' élément d ' obturation du clapet primaire et en poursuivant sa course le contraint en ouverture.The safety valve stem continues to descend. The lower end of its rod 23 comes into thrust contact with the shutter element of the primary valve and by continuing its travel forces it to open.
On libère ainsi le passage du fluide sous pression vers le conduit 15 et l'entrée 14 qui se trouve reliée à la bâche. Ceci permet d'évacuer le fluide de la chambre 6 vers la bâche à travers la chambre-sas 9 et le conduit 15.This frees the passage of the pressurized fluid towards the conduit 15 and the inlet 14 which is connected to the cover. This allows the fluid to be evacuated from the chamber 6 towards the tank through the airlock chamber 9 and the conduit 15.
Le clapet de sécurité étant en position ouverte, son joint ne risque pas de dégradation ou de sortie de son logement.The safety valve being in position open, its seal does not risk damage or exit from its housing.
Arrêt de la descente de la tige sous charge :Stopping the lowering of the rod under load:
Si l'on coupe l'alimentation en fluide moteur sous pression en 3, la commande en ouverture des clapets n'est plus maintenue et on provoque de la même façon que ci-dessus un retard à la fermeture du clapet de sécurité 13 par rapport au clapet primaire 11. L'ensemble de l'équipage mobile dont le piston-poussoir 30 remonte.If the supply of pressurized working fluid is cut at 3, the valve opening control is no longer maintained and a delay in closing the safety valve 13 is caused in the same way as above. to the primary valve 11. The whole of the mobile assembly, the push-piston 30 of which rises.
Il est important de comprendre que l'on recherche dans cette invention une fermeture du clapet de sécurité sous faible débit d'huile de façon à éviter d'endommager ou de déloger le joint de ce clapet et garantir une grande fiabilité de fonctionnement.It is important to understand that it is sought in this invention to close the safety valve under low oil flow so as to avoid damaging or dislodging the seal from this valve and guaranteeing high operating reliability.
La rentrée de la tige du vérin peut également résulter d ' une ouverture autrement commandée des clapets c'est-à-dire indépendante de la pression motrice provoquant la rentrée de la tige.The retraction of the cylinder rod can also result from an otherwise controlled opening of the valves, that is to say independent of the driving pressure causing the retraction of the rod.
Pour rentrer la tige on pourrait aussi utiliser la force de gravité provenant de la plateforme chargée. II faut préciser ici que les perfectionnements de simplification décrits qui caractérisent la dernière variante s ' appliquent aux variantes précédentes et que toutes les formes techniques de clapets sont possibles. Bien entendu, à branchement identique, le dispositif selon l'invention peut être orienté au montage dans le sens contraire de celui représenté sur les figures ou selon toute autre orientation de son support. To retract the rod, one could also use the force of gravity coming from the loaded platform. It should be specified here that the simplification improvements described which characterize the last variant apply to the preceding variants and that all the technical forms of valves are possible. Of course, with identical connection, the device according to the invention can be oriented for mounting in the opposite direction to that shown in the figures or according to any other orientation of its support.

Claims

REVENDICATIONS
1. Dispositif de maintien en position de la tige d'un vérin hydraulique (1) au moins à simple effet comprenant une chambre motrice par exemple une chambre de sortie ( 6 ) de sa tige ( 7 ) et une deuxième chambre utilisée comme chambre de rentrée ( 5 ) de sa tige et au moins un clapet anti-retour (11) à rappel élastique sur le circuit d'alimentation d'une des chambres, monté passant vers cette chambre, dispositif constitué d'un bloc hydraulique d'isolement (2) à travers lequel est alimentée cette chambre caractérisé en ce que :1. Device for holding in position the rod of a hydraulic cylinder (1) at least single acting comprising a driving chamber for example an outlet chamber (6) of its rod (7) and a second chamber used as a chamber reentry (5) of its rod and at least one non-return valve (11) with elastic return on the supply circuit of one of the chambers, mounted passing towards this chamber, device consisting of a hydraulic isolation block ( 2) through which this chamber is supplied, characterized in that:
. le clapet anti-retour (11) dit clapet antiretour primaire (11) est complété par un clapet anti- retour de sécurité (13) à rappel élastique séparé du clapet primaire (11) par une chambre-sas (9) dont ils équipent chacun un des deux orifices d'extrémité pour l'alimentation d'une des chambres du vérin hydraulique, les deux clapets (11) et (13) étant montés passants dans le même sens que le passage du fluide moteur vers cette chambre ;. the non-return valve (11) called the primary non-return valve (11) is completed by a non-return safety valve (13) with elastic return separated from the primary valve (11) by an airlock chamber (9) with which they are each fitted one of the two end orifices for supplying one of the chambers of the hydraulic cylinder, the two valves (11) and (13) being mounted to pass in the same direction as the passage of the working fluid to this chamber;
. des moyens de fermeture différée du clapet de sécurité ( 13 ) par rapport à la fermeture du clapet primaire (11), . un moyen de commande en ouverture du clapet de sécurité (13) dont l'ouverture provoque celle du clapet primaire (11).. means for deferred closing of the safety valve (13) relative to the closing of the primary valve (11),. a means for controlling the opening of the safety valve (13), the opening of which opens that of the primary valve (11).
2. Dispositif de maintien selon la revendication 1 , caractérisé en ce que les moyens de fermeture différée du clapet de sécurité (13) par rapport au clapet primaire (11) est un moyen de retard par un ralentissement de sa course de retour.2. Holding device according to claim 1, characterized in that the means for deferred closure of the safety valve (13) relative to the primary valve (11) is a delay means by slowing down its return stroke.
3. Dispositif de maintien selon la revendication 2, caractérisé en ce que le ralentissement de la course retour du clapet de sécurité (13) provient d'un effet d'amortissement d'un élément solidaire de son corps. 3. Holding device according to claim 2, characterized in that the slowing down of the return stroke of the safety valve (13) comes from a damping effect of an element secured to its body.
4. Dispositif de maintien selon la revendication précédente, caractérisé en ce que l'effet d'amortissement est obtenu par laminage d'huile.4. Holding device according to the preceding claim, characterized in that the damping effect is obtained by rolling oil.
5. Dispositif de maintien selon la revendication 3, caractérisé en ce que l'effet d'amortissement est obtenu par le frottement visqueux d'une partie de la tige du clapet de sécurité (13).5. Holding device according to claim 3, characterized in that the damping effect is obtained by the viscous friction of a part of the stem of the safety valve (13).
6. Dispositif de maintien selon la revendication 1, caractérisé en ce que la commande en ouverture du clapet primaire (11) est une liaison de commande en ouverture qui provoque par transmission à travers le clapet de sécurité ( 13 ) 1 ' ouverture du clapet primaire (11).6. Holding device according to claim 1, characterized in that the opening control of the primary valve (11) is an opening control link which causes by transmission through the safety valve (13) 1 'opening of the primary valve (11).
7. Dispositif de maintien selon la revendication précédente, caractérisé en ce que la transmission de commande en ouverture du clapet primaire (11) présente un jeu de transmission qui dissocie physiquement les deux clapets.7. Holding device according to the preceding claim, characterized in that the control transmission when opening the primary valve (11) has a transmission clearance which physically separates the two valves.
8. Dispositif de maintien selon la revendication précédente, caractérisé en ce que la liaison de commande en ouverture du clapet primaire (11) se termine par une tige (23) solidaire du corps du clapet de sécurité ( 13 ) , tige dont la longueur laisse un jeu (25) entre son extrémité et le corps du clapet primaire (11) lorsque les deux clapets sont fermés.8. Holding device according to the preceding claim, characterized in that the control link for opening the primary valve (11) ends with a rod (23) integral with the body of the safety valve (13), a rod whose length allows a clearance (25) between its end and the body of the primary valve (11) when the two valves are closed.
9. Dispositif de maintien selon les revendications précédentes 6 et 7, caractérisé en ce que la liaison de la commande en ouverture du clapet primaire (11) à travers le clapet de sécurité (13) comprend le moyen de retard à la fermeture du clapet de sécurité ( 13 ) par rapport à celle du clapet primaire (11).9. Holding device according to the preceding claims 6 and 7, characterized in that the connection of the command to open the primary valve (11) through the safety valve (13) comprises the delay means for closing the valve. safety (13) relative to that of the primary valve (11).
10. Dispositif de maintien selon l'une quelconque des revendications 1 et de 5 à 8, caractérisé en ce que le clapet de sécurité ( 13 ) est commandé en ouverture par une pression.10. Holding device according to any one of claims 1 and 5 to 8, characterized in that the safety valve (13) is controlled to open by pressure.
11. Dispositif de maintien selon la revendication précédente caractérisé en ce que la pression de commande est la pression d ' actionnement de 1 ' autre chambre du vérin.11. Holding device according to previous claim characterized in that the control pressure is the actuating pressure of the other chamber of the jack.
12. Dispositif de maintien selon la revendication précédente, caractérisé en ce que le clapet de sécurité ( 13 ) est commandé en ouverture par la pression actionnant la tige (7) du vérin en rentrée.12. Holding device according to the preceding claim, characterized in that the safety valve (13) is controlled in opening by the pressure actuating the rod (7) of the cylinder in re-entry.
13. Dispositif de maintien selon la revendication 9 caractérisé en ce que la liaison de commande en ouverture et le moyen de retard sont constitués d'une liaison mécanique composite (29) formée d'une suite d'éléments comprenant un piston- poussoir (30) sur lequel s'exerce une pression de commande, un élément de liaison sous la forme d'une masselotte (34) à déplacement guidé dans un alésage- guide (35), masselotte (34) en contact de poussée avec le piston-poussoir ( 30 ) , de 1 ' extrémité conformée en piston d'extrémité (40) d'une tige constituant la prolongation du corps ( 20 ) du clapet de sécurité ( 13 ) , ce piston d'extrémité (40) coulissant avec jeu dans le même alésage-guide (35) que la masselotte(34) , et en ce que la masselotte (34) et le piston d'extrémité (40) sont distants sur l'alésage-guide (35) d'un espace formant avec la paroi latérale de l'alésage-guide (35) une chambre-réservoir (42) d'huile et en ce que le piston-poussoir (30) appuyant sur la masselotte (34) est mobile dans une chambre (32) ouverte à l'atmosphère et reçoit la pression du fluide alimentant la chambre opposée du vérin à celle alimentée à travers le sas (9).13. Holding device according to claim 9 characterized in that the opening control link and the delay means consist of a composite mechanical link (29) formed of a series of elements comprising a push-piston (30 ) on which a control pressure is exerted, a connecting element in the form of a counterweight (34) with guided movement in a guide bore (35), counterweight (34) in thrust contact with the push piston (30), one end shaped as an end piston (40) of a rod constituting the extension of the body (20) of the safety valve (13), this end piston (40) sliding with play in the same guide bore (35) as the counterweight (34), and in that the counterweight (34) and the end piston (40) are spaced apart on the guide bore (35) by a space forming with the side wall of the guide bore (35) an oil reservoir chamber (42) and in that the push piston (30) pressing on the counterweight (34) is movable in a chamber (32) open to the atmosphere and receives the pressure of the fluid supplying the chamber opposite the jack to that supplied through the airlock (9).
14. Dispositif de maintien selon l'une quelconque des revendications précédentes, caractérisé en ce que le clapet de sécurité (13) est un clapet (26) à joint d' étanchéité. 14. Holding device according to any one of the preceding claims, characterized in that the safety valve (13) is a valve (26) with a seal.
15. Dispositif de maintien selon l'une quelconque des revendications précédentes, caractérisé en ce que la chambre située sous le piston-poussoir (30) est une chambre-tampon (54) remplie d'huile isolée de l'atmosphère et reliée à l'entrée (14) du fluide moteur par une dérivation ( 53 ) .15. Holding device according to any one of the preceding claims, characterized in that the chamber located under the push-piston (30) is a buffer chamber (54) filled with oil isolated from the atmosphere and connected to the inlet (14) of the working fluid by a bypass (53).
16. Dispositif de maintien selon la revendication 3, caractérisé en ce que l'effet d'amortissement est obtenu par les différences de raideur des clapets (11) et (13).16. Holding device according to claim 3, characterized in that the damping effect is obtained by the differences in stiffness of the valves (11) and (13).
17. Dispositif de maintien selon la revendication 3, caractérisé en ce que l'effet d'amortissement est obtenu par des différences de conformation et de dimensions des composants hydrauliques .17. Holding device according to claim 3, characterized in that the damping effect is obtained by differences in conformation and dimensions of the hydraulic components.
18. Dispositif de maintien selon la revendication 3 ou 16 ou 17, caractérisé en ce que l'effet d'amortissement est obtenu par la combinaison de l'amortissement hydraulique avec les différences de raideur des ressorts de rappel des ressorts des clapets et avec la différence de conformation et de dimensions des composants hydrauliques. 18. Holding device according to claim 3 or 16 or 17, characterized in that the damping effect is obtained by the combination of hydraulic damping with the differences in stiffness of the return springs of the valve springs and with the difference in conformation and dimensions of hydraulic components.
19. Dispositif de maintien selon l'une quelconque des revendications précédentes, caractérisé en ce que le vérin est à simple effet.19. Holding device according to any one of the preceding claims, characterized in that the jack is single acting.
20. Dispositif de maintien selon l'une quelconque des revendications précédentes, caractérisé en ce que 1 ' actionnement du clapet de sécurité (13) est assuré par un moyen quelconque indépendant par exemple électromécanique, électromagnétique ou tout autre moyen.20. Holding device according to any one of the preceding claims, characterized in that the actuation of the safety valve (13) is ensured by any independent means, for example electromechanical, electromagnetic or any other means.
21. Dispositif de maintien selon l'une quelconque des revendications précédentes, caractérisé en ce que sur le sas ( 9 ) est monté un capteur ou détecteur (44) sensible à la pression, le dépassement d'une pression de référence étant exploité par un circuit de détection et d'alerte. 21. Holding device according to any one of the preceding claims, characterized in that on the airlock (9) is mounted a pressure sensitive sensor or detector (44), the exceeding of a reference pressure being exploited by a detection and alert circuit.
EP97913266A 1996-11-07 1997-11-06 Device for holding in position the rod of a pressure cylinder Expired - Lifetime EP0935715B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9613778 1996-11-07
FR9613778A FR2755481B1 (en) 1996-11-07 1996-11-07 DEVICE FOR HOLDING IN POSITION AND UNDER LOAD OF A HYDRAULIC CYLINDER
PCT/FR1997/001994 WO1998020260A2 (en) 1996-11-07 1997-11-06 Device for holding in position the rod of a pressure cylinder

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EP0935715A1 true EP0935715A1 (en) 1999-08-18
EP0935715B1 EP0935715B1 (en) 2004-01-21

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CN (1) CN1103411C (en)
AT (1) ATE258274T1 (en)
CA (1) CA2270579A1 (en)
DE (1) DE69727307T2 (en)
ES (1) ES2216132T3 (en)
FR (1) FR2755481B1 (en)
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Also Published As

Publication number Publication date
EP0935715B1 (en) 2004-01-21
CN1103411C (en) 2003-03-19
ES2216132T3 (en) 2004-10-16
DE69727307T2 (en) 2004-11-18
WO1998020260A3 (en) 2002-10-03
RU2191298C2 (en) 2002-10-20
ATE258274T1 (en) 2004-02-15
FR2755481A1 (en) 1998-05-07
DE69727307D1 (en) 2004-02-26
FR2755481B1 (en) 1998-12-24
US5913810A (en) 1999-06-22
WO1998020260A2 (en) 1998-05-14
UA46875C2 (en) 2002-06-17
CN1244236A (en) 2000-02-09
CA2270579A1 (en) 1998-05-14

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