EP0054477B1 - Motorized installation with jacks for producing the continuous movement of an oblong object in the direction of its axis and/or for moving an element along this object - Google Patents

Abstract

The invention provides a propulsive-force jack installation for producing the continuous movement of an oblong object (1) in the direction of its axis and it is characterized in that it comprises two jack assemblies whose pistons (6, 6') work in seesaw fashion, a piston (6) of one assembly taking in charge said object (1) as soon as the piston (6') of the other assembly ceases this action, offload movement of the piston (6 or 6') and its locking on the object (1) being controlled automatically just before the arrival at the end of travel under load of the other piston (6' or 6) and the offload descent of one piston (6 or 6') being controlled automatically at a time which follows the beginning of the taking in charge of the object by the other piston (6' or 6). The invention may be applied to hoisting, self-raising, prospection, or working platforms at sea.

Description

The present invention relates to a power plant with jacks for producing the continuous movement of an oblong object in the direction of its axis, in particular when this axis is vertical, and / or for moving an element along said object.

By "oblong object" is meant to designate any kind of elongated object, such as bar, rod, tube, cable, etc., of uniform or non-uniform cross section, it being understood that by "axis is meant the general direction in which extends said object, and not necessarily an axis in the geometric sense of the term, that is to say an axis of revolution or symmetry.

The object in question can constitute any mobile mechanical member, for example a hoisting member, the installation in question then being fixed. On the contrary, it can be fixed (post), in which case the installation in question is mobile along this object and can in turn entail, for example to hoist it, any element.

Motor installations are already known for producing the displacement of an oblong object, or of an element along such an object, in particular with jacks, but no one has so far been known which is capable of produce a perfectly continuous movement of the object or element, without jerks, and without downtime.

There are thus known, for example from document GB-A-1 309 232, installations of the general type comprising on the one hand at least two sets of jacks, the piston or pistons of each set being associated with locking means specific to them. selectively, momentarily and automatically secure said object, their body being fixed (in the case of a movable oblong object) or mobile and secured to an element to be moved along said object (in the case of a fixed oblong object), and on the other hand, a device for supplying the bodies of the cylinders with hydraulic fluid, provided with automatic control means (pumps; solenoid valves; position detectors; amplifiers; etc.) for supplying or evacuating the fluid on either side of said pistons, the arrangement and operation of the aforementioned locking and control means being ensured in such a way, at least, that the taking up of said object by the piston or pistons of a cylinder assemblies are performed at the time that the piston or pistons of the other set of cylinders cease their own taking over of said object, the piston or pistons of one set having with respect to those of the other set, and in synchronism, a general rocking movement.

However, this is an installation using self-tightening pliers for temporarily securing the pistons of the cylinder assemblies of the object to be moved, which consists of a cable or the like, moved horizontally.

Such an installation would not be suitable for a vertical movement of a heavy object when it comprises for this purpose, as locking means, pin systems, these being intended to engage in corresponding openings of the object, because then there is the problem of compensating for the clearances, which are inevitable between said pins and the cooperating openings of the object.

Document FR-A-2169 048 describes an installation comprising a transport trolley for very heavy loads, using a main hydraulic cylinder and a hydraulic fixing cylinder, and it would not be adapted to the problem either. , which is in particular that of the continuous displacement of an oblong object in the direction of its axis, in particular when this axis is vertical.

The document FR-A-1 525 052 describes a hydraulic device for hauling a cable, again using two jacks working alternately, one performing a traction movement, while the other returns empty in its starting position, but again such a device is not suitable for moving a load in an essentially vertical direction.

The object of the present invention is to fill this gap in the technique and, for this purpose, a power plant with cylinders in accordance with the invention is characterized in that said empty displacement of the piston or pistons takes place at higher speed. that their displacement under load, to allow a catching up of the games at the level of the locking means, in order to avoid suddenly.

Another object of the invention consists in the production of a hydraulic circuit, as described in claim 8, for the supply of this power plant.

The invention may include other provisions, in particular to allow a rocking movement perfectly synchronized between said pistons of the cylinder assemblies, and to allow easy blocking on the object, and in particular the installation above defined under its the most general form can also be characterized, for this purpose, in that the arrangement and operation of said locking and control means are also ensured so that from a stop position at the end of stroke under load, and after release, the start of the empty return of the piston (s) of an actuator assembly to their starting position, namely the start of their empty movement in the opposite direction to the direction of relative displacement of the object with respect to this assembly, is automatically controlled in an instant which follows the start of the taking over of said object by the piston or pistons of the other cylinder assembly.

It is understood that the period of time which elapses between this start of treatment and the instant in question may correspond approximately to the time necessary to ensure release at the end of the race under load. This will also be better seen later.

In terms of practical implementation, one can provide, for the cylinder assemblies of an installation according to the invention, any embodiment adapted to the problem posed, and in particular that it comprises two sets of cylinders each comprising a annular piston surrounding said oblong object, the two pistons being mounted in a common cylinder body also annular and surrounding said object.

This arrangement advantageously makes it possible to obtain a compact and robust installation, and also allows a simplification, the chambers of the two sets of jacks being able to communicate directly inside the common jack body. One can also facilitate, in this way, the mechanical connection (by bolts or the like) between the pistons and the oblong object.

However, other arrangements can be made, and in particular that the installation comprises two sets of cylinders each comprising an annular piston surrounding said oblong object, the two pistons being mounted in two separate cylinder bodies, also annular, coaxial and surrounding said object. .

It is also possible, in certain application cases, to couple conventional cylinders or double piston single cylinders mounted around said oblong object in an arrangement allowing a balancing of the forces on the pistons and a global or resulting action directed along the axis. said object.

Whatever the mode of execution chosen, it will be possible to use, moreover, for the actuation of the aforementioned blocking and control means, all appropriate means of detection, regulation and the like, common in the kind of technique in question, and provide in particular that the cylinder body or bodies are associated with detectors of the position of the piston in the corresponding body, these detectors being connected, by means of amplifiers or the like, on the one hand to the electro -valves or the like, capable of controlling the supply or evacuation of hydraulic fluid into or out of the cylinders bodies, on one side or the other of the piston whose position is detected and / or of the piston of other cylinders, and on the other hand with said blocking means, to ensure the momentary securing or detachment between pistons and oblong object.

• la figure 1 représente schématiquement une installation conforme à l'invention, du type comprenant un corps de vérin annulaire commun à deux ensembles à vérins, ce corps étant représenté en demi-coupe et demi-vue extérieure ;
• la figure 2 représente de même schématiquement une autre installation conforme à l'invention, du type comprenant deux ensembles à vérins à piston annulaire, les pistons annulaires étant ici montés dans des corps de vérins séparés ;
• la figure 3 représente schématiquement encore une autre installation conforme à l'invention, du type comprenant deux ensembles à vérins, à couples de vérins classiques ; et
• la figure 4 est un exemple d'un des diagrammes possibles, représentant, en fonction du temps, les déplacements des pistons desdits ensembles à vérins.

Embodiments of the invention will now be described by way of non-limiting examples, with reference to the figures in the appended drawing in which:

• Figure 1 schematically shows an installation according to the invention, of the type comprising an annular cylinder body common to two sets of cylinders, this body being shown in half-section and half external view;
• FIG. 2 likewise schematically represents another installation in accordance with the invention, of the type comprising two sets of cylinders with an annular piston, the annular pistons being here mounted in separate cylinder bodies;
• FIG. 3 schematically represents yet another installation according to the invention, of the type comprising two sets of jacks, with pairs of conventional jacks; and
• Figure 4 is an example of one of the possible diagrams, representing, as a function of time, the movements of the pistons of said cylinder assemblies.

In Figure 1, there is referenced at 1, in the form of a tube, the oblong object which it is desired to subject to a continuous displacement in the direction of its axis 2. The cylinder assembly comprises in this example two jacks having a common body 3 mounted, on a fixed support 4, so as to surround said tube 1. The body 3 consists of two cylindrical and concentric walls 3a and 3b connected at both ends by bottoms 3c and thus defining in the body 3 a common annular chamber 5. The diameter of the inner tubular wall 3a is slightly greater than that of the tube 1.

In the annular chamber 5 are slidably mounted two annular pistons 6 and 6 'each extended by a tubular part, respectively 7 and 7', leaving the common body 3 by the two ends of the latter and each of which carries means for the end blocking, respectively 8 and 8 '. These means can be constituted by any means adapted to temporarily block the corresponding tubular part 7 or 7 'on the tube 1; it may, for example, be locking means comprising pins or the like, respectively 9 and 9 ′, adapted to move radially towards the axis 2 or in the opposite direction, either to be able to engage in a light or the like 10 of the tube is to be able to disengage from it, it being understood that the lights 10 can be distributed at constant spacings both according to the length of the tube and along its periphery.

As regards the seal between the pistons 6, 6 'and their respective tubular part 7, 7' on the one hand and the common cylinder body 3 on the other hand, it can again be ensured by any suitable means and for example, as indicated in the drawing, by annular seals, respectively 11 to 14 and 11 'to 14'.

Also shown in the drawing, in 15, a spacer connecting the two cylindrical walls 3a and 3b but leaving in communication the upper and lower parts of the chamber 5, and, in 16, 16 ', webs or the like reinforcing the pistons 6, 6 '.

In FIG. 1, the circuit for supplying the chamber 5 with hydraulic fluid has been shown very schematically. It comprises in particular pipes 17 and 17 ′ opening at both ends of the chamber, crossing the bottoms 3c, and a pipe 18 opening into the central part of the chamber crossing the cylindrical wall 3b, these various pipes being able to be placed in communication with pumps 19 and 19 'via valves, respectively 20 to 23 and 20' to 23 ', these valves being connected according to the arrangement indicated in the sin.

The position, in the direction of the axis 2, of the pistons 6, 6 'in the chamber 5 can be determined by means of position detectors (not shown) and which make it possible to determine the instants at which these pistons arrive, for the piston 6 at the levels indicated by the lines N1, N2, N3 and N4, and for the piston 6 'at the levels indicated by the lines N'1. N'2, N'3 and N'4.

In order not to burden the drawing, the control links between the level detectors and the locking means 8, 8 ′ on the one hand, and the various valves 20 to 23 on the other, have not been shown. and 20 'to 23'. The explanations which will follow on the operation of the installation which has just been described will easily make it possible to see how these operational links between the various organs of the installation must be carried out.

That said, for this explanation of the operation of the installation, reference is made to FIGS. 1 and 4.

In FIG. 4, time is shown on the abscissa and the position of the pistons 6, 6 ′ along the ordinate in the direction of the axis 2. The parts in reinforced line of the two diagrams represented in this figure designate the displacements of the pistons in load, that is to say when by means of pins 9 or 9 'they exert a thrust (which will be assumed directed upwards in FIG. 1) on the tube or other oblong object 1.

It has been assumed that at time t = 0, the piston 6 goes up in load while the piston 6 'goes down (in FIG. 4, for slopes under load, we have indicated lower slopes, in absolute value, to the slopes of descent without charge). At this time, the valves 21, 23, 20 'and 22' are open, while the valves 20, 22, 21 'and 23' are closed.

When the piston 6 'reaches its lower level N'4, the automatic control causes the opening of the valves 21' and 23 'and therefore the stop of this piston in the low position.

When the piston 6 arrives at level N2, the valves 20 'and 22' close, which causes the piston 6 'to rise and the pin 9' to lock in the corresponding lumen 10 of the tube 1 (see part reference B on Figure 4).

When the piston 6 arrives at level N1. the valves 20 and 22 open, which causes the piston to stop, and the unlocking, that is to say the extraction of pin 9 out of the corresponding light 10 (operation designated by the letter D in FIG. 4). It should be noted that this unlocking can be carried out conveniently because then the piston 6 no longer exerts force on the tube 1.

When the piston 6 ', which has started to increase in load, by driving the tube 1, from the moment at which the piston 6 has finished exercising this action, arrives at level N'3, the valves are automatically closed 21 and 23, which causes the descent of the piston 6, the piston 6 'continuing its rise in load.

When the piston 6 arrives at level N4, the valves 21 and 23 open, which causes the piston to stop.

When the piston 6 'then arrives at level N'2, the valves 20 and 22 are closed simultaneously to again drive the piston 6 upwards and at the same time the locking of the spindle 9 on the corresponding light 10 (reference B).

When the piston 6 'arrives at the level N'1, the valves 20' and 22 'are automatically opened, which causes this piston to stop and therefore the tube 1 to be taken over by the piston 6 Pin 9 'is unlocked (reference D).

When the piston 6 arrives at level N3, the valves 21 ′ and 23 ′ are automatically closed, which causes the piston 6 ′ to descend.

We then returned to the starting point and the cycle then continues in exactly the same way.

In FIG. 4, the operational interconnections between the controls of the pistons 6 and 6 ′ have been shown diagrammatically in the form of dashed vertical lines I, II and III.

Line I clearly shows that the taking over of the tube 1 by the piston 6 'immediately follows the end of the taking over of this tube by the other piston 6, as well as the taking over of the tube by the piston 6 immediately follows the end of the support of this tube by the piston 6 '.

Line II shows that when a piston comes under load at level N2 or N'2, it automatically controls the start of the rise of the other piston and its locking in relation to tube 1.

Finally, line III shows that when a piston arrives under load at level N3 or N'3, it automatically controls the start of the descent with no load from the other piston.

It should be emphasized that the diagrams represented in this FIG. 4 are only given by way of illustration to show a possible example of operation, but that it would be possible to envisage many others.

It should be noted, moreover, that the addition to the installation which has just been described of suitable devices could also make it possible to obtain different safety or other states, stopping under load on the two pistons, or again the reversal of the direction of movement of the object 1 or the reversal of the direction of the force exerted on it.

In fact, the object 1 may in particular be an object to be hoisted, or on the contrary an object to be lowered, for example to sink it into the ground, to effect sinking, drilling or the like. This object 1, instead of being mobile, as in the example which has just been described, could also be constituted by a fixed post, and in this case of course, it is the common cylinder body 3 which would move, likewise in a perfectly continuous manner, along the object 1, by driving any element, for example an element to be hoisted at the top of the post or the like. We can consider in particular many its applications of this type in the technique of oil drilling, and in particular but not limited to the hoisting of self-elevating platforms for exploration or exploitation at sea.

In Figures 2 and 3, there is also shown schematically alternative embodiments of an installation also according to the invention.

According to Figure 2, where the locking means 8, 8 'on the object 1 can be of the same type as according to Figure 1, there are provided two separate cylinder bodies 24 and 24', annular, surrounding the oblong object 1 and in each of which is mounted a piston also annular, respectively 25 and 25 '. The means for supplying the two separate cylinder bodies with hydraulic fluid can be of the same type as those which have been previously described and they have been globally referenced at 26 for the body 24 and 26 'for the body 24'. In a similar way to what was the case for FIG. 1, there is a communication between the two actuator bodies 24 and 24 ′, by a link referenced at 27, 27 ′, but it is understood that one could also consider a separation between the two actuator bodies 24 and 24 'and complete independence between the hydraulic fluid supplies.

Operation may in any case be similar to that which has been described with reference to FIG. 1.

The same remarks are valid for the embodiment of FIG. 3.

In this figure, there has been shown, instead of annular cylinders, single cylinders whose bodies have been referenced at 28 and 28 'and the pistons at 29 and 29'. They can be supplied as shown in Figure 2 (supplies 30 and 30 '). In the figure, only one pair of jacks has been shown, but in reality several pairs are regularly used around the object 1 for balancing the forces exerted by the pistons 29, 29 'on this object.

Again, this object can be arbitrary and is referenced in Figure 3 locking means 31 and 31 'of the type with clamps. Of course, it will be advisable to use collars whose tightening on the object 1 and loosening can be controlled automatically from appropriate control signals, for example electrical or hydraulic.

In the case of application, one could also consider a separation, between the pistons 29, 29 'and the oblong object 1, not at the level of clamps or the like 31, 31' but at the level of the connection between the ends of the rods 32 and 32 'of the pistons and a member for securing to the object 1, which member would then be permanently mounted thereon.

Claims (8)

1. A drive installation employing jacks to produce continuous movement of an oblong article in the direction of its axis, particularly when said axis is vertical, and/or for moving an element along the said article, said installation comprising, on the one hand, at least two jack systems, the piston or pistons (6, 6') of each system being associated with locking means (8, 8') adapted to connect them to the said article selectively, instantaneously and automatically, the jack bodies being stationary (in the case of a movable oblong article) or movable and connected to an element for moving along the said article (in the case of a stationary oblong article), and, on the other hand, a system for feeding the jack bodies with hydraulic fluid (17 to 23), provided with automatic control means (pumps; solenoid valves ; position detectors ; amplifiers ; etc.) for supplying or discharging fluid on one side and the other of the said pistons, the said locking and control means being so arranged and so operating that engagement of the said article by the piston or pistons of one of the jack systems is effected without any break at the time when the piston or pistons of the other jack system cease their own engagement of said article, the piston or pistons of a system having a general rocking movement in relation to and in synchronism with those of the other system, the said locking and control means also being so arranged and operating that the start of a no-load movement of the piston or pistons (6 or 6') of one of the jack systems in the direction of relative movement of said article (1) with respect to said system, and their locking on the article, are controlled automatically at a time (at N'2 or at N2) before the piston or pistons (6' or 6) of the other jack system reach the end of their on-load movement, and moving in the same direction, characterised in that the said no-load movement of the piston or pistons takes place at a higher speed that their on-load movement to allow any play fo be taken up in the locking means so as to avoid any impact.

2. Installation according to claim 1, characterised in that the said locking and control means are also so arranged and operate that, starting from a stop position at the end of the on-load movement (at N1 or at N'1) and after unlocking, the start of the no-load return movement of the piston or pistons (6 or 6') of a jack system to their starting position (N4 or N'4). i.e. the start of their no-load movement in the opposite direction to the direction of relative movement of the article 1 with respect to said system, is controlled automatically at a time (at N'3 or N3) after the piston or pistons (6' or 6) of the other jack system have started to engage the article (1).

3. An installation according to claim 1 or 2, characterised in that it comprises two jack systems each comprising an annular piston (6, 6') surrounding said oblong article (1), the two pistons being mounted in a likewise annular common jack body (3) surrounding said article.

4. An installation according to any one of the preceding claims, characterised in that each of the jack systems is associated with its own pump (19, 19') and its own hydraulic circuit (20-23, 20'-23'), the circuits having a common connection (18) connected to the jack bodies.

5. Installation according to any one of claims 1 to 3, characterised in that it comprises two jack systems (24, 24') each comprising an annular piston (25, 25') surrounding said oblong article, the two pistons being mounted in two separate jack bodies which are also annular, coaxial, and surround the said article.

6. Installation according to any one of claims 1 to 3, characterised in that it comprises pairs of conventional jacks (28, 28') or double-piston mono-jacks mounted around the said oblong article in an arrangement which allows the forces on the pistons (29, 29') to be balanced and which gives an overall action or resultant oriented along the axis of said article.

7. Installation according to any one of the preceding claims, characterised in that the jack body or jack bodies (3) are associated with detectors for detecting the position of the pistons (6, 6') in the corresponding body, said detectors being connected, through the agency of amplifiers or the like, on the one hand to solenoid valves or the like (20-23, 20'-23'), adapted to control the supply or discharge of hydraulic fluid to or from the jack bodies (3), on one side or the other of the piston (6, or 6') whose position is detected and/or the piston of other jacks, and, on the other hand, to the said locking means (8, 8') to provide instantaneous connection or disconnection between pistons (6, 6') and the oblong article (1).

8. A hydraulic circuit adapted to feed two jack systems in a predetermined sequence of phases of on-load movement and no-lead return movements in such a manner than on-load movement (1) of one of the jack systems is immediately followed, without any break, by an on-load movement phase of the other jack system, the two jack systems having a general rocking movement with respect to one another, characterised in that in order to avoid any break between the on-load movement phase of one of the jack systems and the following on-load movement phase of the other jack system each jack system comprises a first chamber (5) and a second chamber, said chambers being separated by a piston (6, 6'), the first chamber of one of the jack systems being connected to the first chamber of the other jack systems or the said two chambers (5) being common, and in that there is provided, for each system, a group of four valves (20-23 ; 20'-23') forming two pairs of two valves, in which the two valves (20, 23 ; 21, 22 ; 20', 23' ; 21', 22') are connected in series and thus have a common point, each of the said pairs of each group being connected between the said first and second chambers of the corresponding jack system, and a pump (19 ; 19') being connected in each group between the said common point of one of the said pairs of valves and the said common point of the other pair of valves.

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