Package lifting system and method

Abstract

The invention relates to a system (1) for lifting a package (C) preferably in the presence of swell, comprising: - at least one lifting cable (3) associated with a winch (4), hauling means (5) comprising a fixed block of sheaves (51) and a mobile block of sheaves (52), - controlled braking means (6), cooperating with said mobile block of sheaves and controllable between an inactive configuration in which said controlled braking means allow free translation of said mobile block of sheaves, and an active configuration in which said controlled braking means allow movement of the mobile block of sheaves in one direction only, - control means (7) for controlling said winch and controlled braking means, and - maneuvering means (8) configured to restore potential energy to said mobile block of sheaves. Figure for abstract: Fig.1

Description

Title of the invention: System and method for lifting parcels Technical field of the invention

[0001] The present invention relates to the technical field of lifting packages.

[0002] It relates more particularly to a system and a method for lifting packages in the presence of a relative movement between the lifting system and the area where the package is located or must be deposited, due for example to swell. State of the art

[0003] It is common to use package lifting systems at sea, particularly for loading or unloading ships, barges or even offshore platforms.

[0004] In this context, a lifting device such as a crane or a gantry is usually used, equipped with at least one cable, one end of which is adapted to be wound onto a winch and the other end of which carries the package.

[0005] In the specific field of lifting at sea, the main difficulty encountered concerns the relative speeds between the reference frame of the lifting equipment and the reference frame on which the package is placed or must be placed.

[0006] Traditionally, the winches of offshore lifting systems have high lifting speeds so as to allow experienced crane operators to follow the movements of the swell by so-called turning and unturning actions.

[0007] The package is initially removed from the deck by always leaving slack in the lifting straps, then by recovering the slack during a phase of raising the package so as to accompany the natural movement of the package imposed by the swell.

[0008] To assist crane operators, there are now cranes with active wave compensation which automatically compensate for relative movements between the two reference frames.

[0009] This active compensation aims to keep the cables taut at all times so as to avoid a slack take-up shock.

[0010] However, in practice, this technical solution is heavy, expensive and very dependent on sensors.

[0011] Another solution consists of cranes with shock absorbers: a shock absorber device, generally hydraulic, filters as dynamically as possible any force exceeding a certain pre-set threshold.

[0012] However, this type of solution is not able to recover significant shocks due to very high relative speeds.

[0013] In view of the above, it would be interesting to propose alternative solutions suitable for lifting packages in the presence of relative movement due to the swell.

[0014] In particular, it would be interesting to propose a mechanical solution which does not aim solely to treat the effects of shocks but to make them impossible, or at least to limit them. Presentation of the invention

[0015] In this context, the present invention proposes a system for lifting a package, preferably between two reference frames having at least one relative vertical movement, for example for lifting the package in the presence of a relative movement due to swell, which lifting system comprises at least one lifting point which comprises a chassis comprising: - at least one lifting cable associated with: H a winch, for maneuvering said lifting cable, in turns and in reverse, H hauling means comprising: ° a fixed block of sheaves, secured to said chassis, and ° a mobile block of sheaves, cooperating with said chassis by means of sliding means defining a degree of freedom in translation orthogonally to axes of rotation of said blocks of sheaves, the distance dimension of said mobile block of sheaves relative to said fixed block of sheaves being variable, - controlled braking means, cooperating with said mobile block of sheave(s) and controllable between two preferably bistable configurations: H an inactive configuration, in which said controlled braking means allow free translation of said mobile block of sheave(s) according to said degree of freedom in translation, in particular adapted to passive compensation of swell, and H an active configuration, in which said controlled braking means allow the mobile block of sheave(s) to move in a single direction according to said degree of freedom in translation, corresponding to an increase in said distance dimension, - control means, for controlling said winch and said controlled braking means, in particular during the operation of launching or recovering said package, - first operating means which cooperate with said mobile block of sheave(s) and which are configured to restore potential energy to said mobile block of sheave(s) so that: H when said controlled braking means are in inactive configuration, to tend to maintain a constant tension in said at least one lifting cable and, H when said controlled braking means are in active configuration, to tend to increase said distance dimension.

[0016] According to the invention, said sliding means comprise a sliding rod which carries the mobile block of sheave(s), which is guided in translation coaxially with said degree of freedom in translation and which cooperates with said controlled braking means, while said controlled braking means comprise: - at least two jaws which are distributed around said sliding rod, which jaws each comprise a friction face adapted to cooperate with said sliding rod, and - second bistable operating means adapted to move each jaw between two positions: H a distal position, at a distance from said sliding rod, corresponding to said inactive configuration of said controlled braking means, and H a proximal position, resting on said sliding rod, corresponding to said active configuration of the controlled braking means.

[0017] Consequently, the controlled braking means are adapted, in the inactive configuration, to allow the hauling means to take up or give slack to the lifting cable. This configuration is particularly useful when the package must remain placed on a reference frame that is moving relative to that on which the lifting system is located. These controlled braking means are further adapted, in the active configuration, to allow the hauling means to take up slack in the lifting cable but to prevent them from giving slack. This configuration is particularly useful when the package must be torn from the moving reference frame.

[0018] The solution proposed by the invention, using jaws, then proves to be particularly interesting in various respects.

[0019] First of all, it relies essentially or even exclusively on mechanical means (advantageously by limiting the number of sensors and actions of an automaton, in real time), which makes it particularly robust and reliable, even in the difficult environmental conditions of the navy and offshore. Indeed, it is possible to provide that only the winch and the bistable maneuvering means are controlled. It would even be possible to envisage that the bistable maneuvering means are in the form of a simple lever.

[0020] This solution also makes it possible to lift and place packages as gently as possible, whatever the relative speeds of the reference points, even when the latter exceed the recommendations (typically if a particularly high and unpredictable wave occurs).

[0021] Finally, it is inexpensive, light and compact.

[0022] Other advantageous and non-limiting characteristics of the lifting system according to the invention, taken individually or in all technically possible combinations, are the following: - the friction faces of the jaws extend parallel to said degree of freedom in translation; - said second operating means guide the movement of each jaw along an arc-shaped trajectory in which said friction face moves parallel to itself, between said two distal and proximal positions; - the second operating means comprise an actuator and, for each jaw, a deformable parallelogram structure which comprises said jaw, a base, and at least two connecting rods each assembled in free rotation with said base and with said jaw around two separate pivot axes, which deformable parallelogram structure cooperates with said actuator for operating said jaw between its distal position and its proximal position; - at least two connecting rods, belonging to two distinct deformable parallelogram structures, cooperate together by means of gears, so as to ensure the synchronization of the associated jaws; - in the proximal position, the angle between the plane passing through the pivot axes of each connecting rod and the normal to the friction face is between 6 and 9° if the coefficient of adhesion friction between each friction face and said sliding rod is between 0.08 and 0.16; - at each jaw, given a resultant angle, corresponding to an angle formed by the resultant of the forces applied between said jaw and said sliding rod, and an angle at the apex of an adhesion friction cone, corresponding to the maximum angle relative to a contact normal oriented perpendicular to said sliding rod in which a force can be applied to the sliding rod according to said degree of freedom in translation without generating translation of said sliding rod, said lifting system is configured so that, when the jaws are in the active configuration, said resultant angle is less than said angle at the apex of the adhesion friction cone; - the controlled braking means comprise mechanical stops to define an end-of-travel position for the jaws which is located beyond said proximal position and which is such that, in the end-of-travel position, all the components of the controlled braking means are deformed elastically only; - the sliding means are configured so that said sliding rod, and its degree of freedom in translation, are oriented horizontally; - the sliding means are configured so that said sliding rod, and its degree of freedom in translation, are oriented vertically; - when said degree of freedom in translation is oriented horizontally, said sliding rod is carried by support rollers; - when said degree of freedom in translation is oriented vertically, the controlled braking means comprise means for compensating for the weight of the jaws, by example a spring organ or a counterweight; - the first operating means, configured to restore elastic potential energy or gravitational potential energy to said mobile block of sheaves, comprise an elastically deformable member such as a spring or an elastic band, and / or a counterweight; - the controlled braking means comprise safety means which are configured to prevent control from the inactive configuration to the active configuration during a translation of the sliding rod corresponding to a reduction in said distance dimension; - the safety means comprise a safety ring which surrounds said sliding rod so as to move between two positions, namely an active position, during a translation of the sliding rod corresponding to a reduction in said dimension in distance, to cooperate with the jaws in the inactive configuration and prevent control of the inactive configuration towards the active configuration, and an inactive position, during a translation of the sliding rod corresponding to an increase in said dimension in distance, to move away from the jaws in the inactive configuration and to allow control of said inactive configuration towards said active configuration; - the lifting system consists of a crane comprising a lifting point, the chassis of which comprises an upright and a boom, or a gantry comprising at least two lifting points.

[0023] The invention also proposes a method for lifting a package, between two reference frames preferably having at least one relative vertical movement, for example for lifting the package in the presence of a relative movement due to swell, by implementing a lifting system as mentioned above, which lifting method comprises - for the passage from the proximal position to the distal position of the jaws: H the control of the second operating means to move the jaws from the proximal position to the distal position, then, H if a force exerted on the sliding rod coaxially with said degree of freedom in translation in a direction corresponding to a reduction in said dimension in distance is less than a predetermined threshold, execution of said command, otherwise H suspending said command until said effort decreases below said predetermined threshold, then executing said command, - for the transition from the distal position to the proximal position of the jaws: H the control of the second operating means to move the jaws from the distal position to the proximal position, then, H if said distance rating increases, execution of said command, otherwise H suspension of said command until said distance rating increase.

[0024] Preferably, this lifting method comprises the following operations: (i) during an operation to launch said package from the lifting system reference system to a destination reference system: - a step of suspending said package from said lifting cable, in which the jaws are in the distal position and said mobile block of sheave(s) is in an average position centered on an available stroke, - a turning and then drifting step on a course allowing the safety ring to be positioned in the inactive position, - a step of controlling the closing of the jaws towards the proximal position, - a turning step to lift the package and place it above the destination reference, - a stage of lowering said package near the highest wave crests of the swell, - when the package is placed on a wave crest or near a wave crest at the end of a rising front, a step of deflecting, preferably to come tangent to said wave crest, and of passing from the proximal position to the distal position of the jaws, so that when said package transfers its weight from said lifting cable to said destination reference frame, said lifting system ensures passive compensation for the swell, and / or (ii) during an operation to recover said package located on the destination reference, the jaws being in the distal position, said lifting system ensuring passive compensation for the swell, - preferably when said package is in an upward movement, a step of passing the jaws into the proximal position so that said mobile block of sheave(s) continues its movement by increasing said dimension in distance, this up to a wave crest where said mobile block of sheave(s) is blocked in translation, - as soon as the jaws reach the proximal position, a turning step to lift the package and place it above the reference frame of the lifting system, - a step of lowering said package onto the lifting system reference frame.

[0025] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. Detailed description of the invention

[0026] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can to be carried out.

[0027] In the attached drawings:

[0028] [Fig-1] is a general schematic and perspective view of a lifting system according to the invention, according to a first embodiment (vertical), in the form of a crane comprising a lifting point;

[0029] [Fig.2] is a schematic and perspective view of the lifting system according to [Fig.l], on which the chassis is hidden and which illustrates in particular hauling means and braking means of this lifting system;

[0030] [Fig.3] is a schematic and perspective view of controlled braking means which cooperate with the hauling means of [Fig.2], seen in a first direction;

[0031] [Fig.4] is a schematic plan view of the controlled braking means of [Fig.3], seen in a second direction opposite to [Fig.3];

[0032] [Fig.5] is a schematic and perspective view of a safety ring equipping the controlled braking means of [Fig.3];

[0033] [Fig.6] illustrates different configurations which can be taken by the controlled braking means of [Fig.3];

[0034] [Fig.7] is a schematic and perspective view of the lifting system according to a second embodiment (horizontal);

[0035] [Fig.8] is a sectional view along plane AA of [Fig.7].

[0036] Lifting system

[0037] It should be noted that, in these figures, the structural and / or functional elements common to the different variants may have the same references.

[0038] As shown in [Fig.l], the present invention relates to a lifting system 1 designed for lifting a package C.

[0039] This lifting system 1 is in particular suitable for lifting a package C in the presence of relative movement due to swell, in particular for an off-shore or sea application.

[0040] More generally, the lifting system 1, for example a crane or a gantry, is suitable for handling a package C between two reference frames which have a relative movement due to the swell.

[0041] By "swell" is meant the oscillation of the sea surface, in particular due to waves.

[0042] Generally speaking, the highest point of a wave is called the crest; the lowest point is called the trough. The size of the wave is determined by the distance between the crest and the trough. The period is the time elapsed between two crests.

[0043] As discussed below, a “highest peak” advantageously corresponds to the highest peak during a given period of time.

[0044] By “package” we mean any object (or load) intended to be handled by the lifting system 1. Such a package C may have various shapes and sizes. It may, for example, be a basket for the transfer of people ([Fig.l] for example), a container or a boat.

[0045] By “reference frames”, we advantageously include any surface which, for one of them, supports the lifting system 1 and, for the other of them, is intended to receive the package C. In the following, we will speak respectively of the original reference frame Ro and the destination reference frame Rd. This could be, for example, the deck of a ship or a platform, or even the surface of the water.

[0046] Generally speaking and according to the invention, the lifting system 1 comprises at least one lifting point 1a, that is to say a system by which it can lift a package independently. Alternatively, the lifting system 1 may comprise at least two lifting points 1a, to lift several separate packages or to lift the same package by several points.

[0047] According to the invention, this lifting point 1a comprises a chassis 2 equipped with: - at least one lifting cable 3 associated with a winch 4 and hauling means 5, - controlled braking means 6, cooperating with the hauling means 5, - first maneuvering means 8 which cooperate with the hauling means 5 and which are configured to restore potential energy, in particular to keep the hauling means taut and ensure passive compensation for the swell, and - control means 7, for controlling the winch 4 and possibly also controlled braking means 6, in particular during operations of launching or recovering the package C.

[0048] Lifting cable

[0049] The lifting cable 3 is conventional in itself.

[0050] It consists, for example, of a cable made of synthetic material or metallic material.

[0051] This lifting cable 3 is capable of undergoing a tensile force which is generated by the package C suspended from said lifting cable 3.

[0052] In other words, the package C is intended to be suspended from one end of the lifting cable 3 when the other end is wound onto the winch 4. When it is suspended, this package C is thus intended to exert a tensile force, or a tensile force, on the lifting cable 3.

[0053] By “suspended” we mean a configuration in which the package C is located high up and at a distance from the reference points.

[0054] Winch

[0055] Winch 4 is classic in itself.

[0056] This winch 4 is suitable for maneuvering the lifting cable 3: - on a turn, to exert a force on the lifting cable 3 by winding it onto a drum of the winch 4, and advantageously to generate a rise of the package C from the destination reference frame, and - deviates, to release the force on the lifting cable 3 by unwinding from the winch 4, and advantageously to generate a descent of the package C towards the destination reference frame.

[0057] Hauling means

[0058] The hauling means 5, more visible in [Fig.2], comprise: - a fixed block of sheaves 51, secured to chassis 2, and - a mobile block of sheave(s) 52, mounted mobile in translation on the chassis 2 by means of sliding means 53 defining a degree of freedom in translation T.

[0059] In particular, the mobile block of sheave(s) 52 preferably comprises a single sheave 52 or two sheaves 52.

[0060] Preferably, the sheaves 51, 52 (also called “pulleys”) have respective axes of rotation 51', 52', which extend in planes orthogonal to the degree of freedom in translation T (also called “axis of the slide”, which are parallel to each other and which define between them a distance dimension D.

[0061] The distance dimension D is advantageously measured according to the degree of freedom in translation T, described below.

[0062] The sliding means 53 define a degree of freedom in translation for the mobile block of sheaves 52. This is preferably the only degree of freedom between the two blocks of sheaves.

[0063] This degree of freedom in translation T extends along an axis, hereinafter also called "T-slide axis", which can be oriented vertically (Figures 1 to 6) or horizontally (Figures 7 and 8). Of course, this T-slide axis could extend obliquely.

[0064] As developed subsequently, the aforementioned distance dimension D (corresponding to the distance between the rotation axis 52' of the mobile block of sheaves 52 and the rotation axis 51' of the fixed block of sheaves 51, measured on the degree of freedom in translation) is variable.

[0065] For example, the possible travel of the mobile block of sheave(s) 52, depending on the degree of freedom in translation, is for example 1 m to 2 m, for example 1.5 m (i.e. 6 m at the hook).

[0066] Generally, the sliding means 53 comprise for example a sliding spar 531 (also called a “sliding rod”), forming a slide, which carries the movable block of sheave(s) 52.

[0067] Where appropriate, the sliding spar 531 extends coaxially with the slide axis T. This sliding spar 531 is movable along this slide axis T.

[0068] The mobile block of sheave(s) 52 is advantageously carried at the level of one of the ex- ends 531a, 531b of the sliding beam 531.

[0069] As developed below, this sliding spar 531 cooperates with the controlled braking means 6. The latter thus make it possible to brake or block the sliding of the sliding spar 531 and of the mobile block of sheave(s) 52. Here, they also make it possible to guide this sliding spar 531, in translation, along the slide axis T.

[0070] Controlled braking means

[0071] According to the invention, the controlled braking means 6 can be controlled between two configurations, advantageously bistable: an inactive configuration and an active configuration.

[0072] By “bistable”, it is advantageously understood that the inactive configuration and the active configuration constitute stable configurations. Preferably, these controlled braking means 6 cannot be controlled in another configuration; the controlled braking means 6 thus advantageously switch between the inactive configuration and the active configuration. They may, however, possibly have another configuration, in particular when switching from one to the other of the two stable configurations.

[0073] In the inactive configuration, the controlled braking means 6 allow free translation of the movable block of sheave(s) 52 along the slide axis T, in both directions (for example in an oscillating movement).

[0074] As developed subsequently, such an inactive configuration is particularly suitable for passive swell compensation. In this case, the movable block of sheaves 52 and the sliding spar 531 can oscillate freely relative to the fixed block of sheaves 51, particularly as a function of the relative movement between the two reference frames. This is typically the case when the package C is placed on the destination reference frame Rd and the two reference frames Ro, Rd rise and fall relative to each other due to the waves.

[0075] In the active configuration, the controlled braking means 6 allow the mobile block of sheave(s) 52 to move in one direction only along the slide axis T, corresponding to an increase in the aforementioned distance dimension D. In other words, in the active configuration, the hauling means 5 can recover the slack in the lifting cable 3, but they remain blocked when a tensile force is exerted on this lifting cable 3 (when the package C is suspended at the end of this lifting cable 3). For example, in Figures 1 and 2, only the downward movement of the mobile block of sheave(s) 52 is allowed, to ensure the ascent of the package C, its descent being blocked. This is typically the case when the package C was placed on the destination reference frame Rd and it is desired to remove it or when the package C rises relative to the lifting system 1.

[0076] In other words, in the active configuration, the controlled braking means 6 are structured for: - authorize a path of the mobile block of sheave(s) 52 in a first direction along the slide axis T, corresponding to an increase in the distance dimension D, and - prevent a path of the mobile block of sheave(s) 52 in a second direction along the slide axis T, corresponding to a decrease in the distance dimension D.

[0077] Such an active configuration is particularly interesting for allowing the continuation of a movement by increasing the distance dimension D, for example when the package C follows an upward trajectory up to a wave crest, and to prevent it from then descending towards the trough of the wave since it is desired to lift it.

[0078] Bit

[0079] According to the invention, the controlled braking means 6 essentially comprise mechanical means, mounted to move relative to each other to define the aforementioned active and inactive configurations.

[0080] More precisely, according to an example illustrated in [Fig.3], the controlled braking means 6 firstly comprise a base 61, in this case a housing 61, which is fixed to the chassis 2 and which houses jaws 631, 632.

[0081] These jaws 631, 632 are preferably located on either side of the sliding rod 531 so as to be able to sandwich it. Preferably, these jaws 631, 632 are for this purpose mounted to move in a direction inclined relative to the slide axis T to come to bear on this sliding rod 531 or to move away from it, depending on the direction of travel.

[0082] The jaws 631, 632 each further comprise a friction face 631a, 632a, these faces being turned towards each other and towards the sliding rod 531. These friction faces 631a, 632a are intended to cooperate with the sliding rod 531 to ensure its braking.

[0083] The sliding rod 531 is said to be profiled, in the sense that it has, over at least part of its length (that which slides in the housing 61), a section of invariable shape and size.

[0084] The friction faces 631a, 632a of the jaws 631, 632 have shapes which are complementary, in negative, to those of the parts of the sliding rod 531 against which they bear.

[0085] Here, and preferably, the sliding rod 531 has a circular section. Consequently, the friction faces 631a, 632a of the jaws 631, 632 are curved, in the sense that they have sections (in planes orthogonal to the slide axis T) in an arc of a circle, extending over angular sectors less than or equal to 180°.

[0086] Of course, as a variant, the sliding rod 531 could have a section rec tangular, in which case the friction faces 631a, 632a of the jaws 631, 632 would be flat or dihedral. Other shapes would also be possible.

[0087] In practice, the jaws 631, 632 are advantageously in the form of parallelepiped blocks, one of the six faces of which forms the friction face 631a, 632a.

[0088] The jaws 631, 632 could be manufactured from a wide variety of materials. Here, they are formed from a single piece and from a single metallic material, for example from soft stainless steel (while the sliding rod 531 is made from hard stainless steel). Of course, as a variant, it would be possible to manufacture them from another material or from several different materials (for example to coat their friction faces 631a, 632a with a particular material dedicated to braking the sliding rod 531).

[0089] The controlled braking means 6 also comprise second bistable operating means 60 adapted to move the jaws 631, 632 so that the latter can move closer to or away from the sliding rod 531.

[0090] These bistable operating means 60 are shaped to allow the jaws 631, 632 to be moved between two positions, namely: - a distal position in which the jaws 631, 632 extend away from the sliding rod 531, and - a proximal position in which the jaws 631, 632 come to bear on said sliding rod 531.

[0091] “Remote” means that the jaws 631, 632 are in a position spaced from the sliding rod 531 relative to the proximal position, and such that they do not prevent the sliding rod 531 from sliding according to its degree of freedom in translation, in both directions. In practice, in this position, it will be preferred that no contact between the jaws 631, 632 and the sliding rod 531 occurs. But as a variant, a partial sliding support could be envisaged, on the model of motor vehicle brake discs.

[0092] When the jaws 631, 632 are in the distal position (advantageously spaced apart from the sliding rod 531), they therefore do not block the sliding of the sliding rod 531 according to its degree of freedom in translation. Consequently, this distal position corresponds to the inactive configuration of said controlled braking means 6.

[0093] When the jaws 631, 632 are in the proximal position (advantageously resting on the sliding rod 531), they block the sliding of the sliding rod 531 along the slide axis T in one direction only, for the reason which will be described below. Consequently, this proximal position corresponds to the active configuration of the controlled braking means 6.

[0094] Different systems could be envisaged so that, when the jaws are in the proximal position, they block the sliding of the sliding rod 531 in one direction only.

[0095] Here, the second operating means 60 are in practice shaped to guide the movement of the jaws 631, 632 along arc-shaped trajectories, such that the friction faces 631a, 632a move parallel to each other, between the two distal and proximal positions.

[0096] They are more precisely arranged so that, when the jaws 631, 632 move from the distal position to the proximal position, these jaws 631, 632 move along the slide axis T, in a direction corresponding to a reduction in the distance dimension D.

[0097] These second operating means 60 are further shaped so that the arc-shaped trajectories of the friction faces 631a, 632a of the jaws 631, 632 are not tangent to the sliding rod 531. Thus, in the proximal position (when the jaws come to bear on the sliding rod 531), the movement of the sliding rod 531 in one direction (that corresponding to a reduction in the distance dimension D) will tend, taking into account the friction of the jaws 631, 632 on this sliding rod 531, to tighten the jaws 631, 632 against the sliding rod 531. On the contrary, the movement of the sliding rod 531 in the opposite direction will tend to move the jaws 631, 632 away from this sliding rod 531. It is this aspect which here makes it possible to prevent the movement of the sliding rod 531 in one direction only.

[0098] In practice, this so-called “rotary translation” movement of the jaws 631, 632 is operated by two deformable parallelogram structures.

[0099] For each jaw 631, 632, the deformable parallelogram structure comprises:

[0100] - said jaw 631, 632,

[0101] - the base 61, and

[0102] - at least two connecting rods 602, 603, 604, 605, each assembled in free rotation with said base 61 and with said jaw 631, 632 around two separate pivot axes.

[0103] As shown in [Fig. 3], these structures each comprise, for example, two connecting rods 602, 604; 603, 605 which are articulated, here at their ends, on the one hand on the housing 61, and on the other hand on the jaw 631; 632 considered. In other words, each jaw 631, 632 cooperates with a pair of connecting rods 602, 604; 603, 605.

[0104] For this, the housing comprises a bottom wall 610 from which rise four first cylindrical pads 612, 613, 614, 615 of revolution around axes parallel and orthogonal to the slide axis T.

[0105] Each connecting rod 602, 603, 604, 605 has a plate shape pierced at its two ends by openings, one of which is engaged on one of these first studs 612, 613, 614, 615. The first studs 612, 613, 614, 615 thus make it possible to ensure the guidance of each associated connecting rod 602, 603, 604, 605 according to pivoting movements around respective pivot axes corresponding to the axes plots.

[0106] In the same way, each jaw 631, 632 carries two second studs, not visible in [Fig. 3], cylindrical in revolution around axes parallel to the axes of the first studs 612, 613, 614, 615. The second opening of each connecting rod 602, 603, 604, 605 is then engaged on one of these second studs.

[0107] Generally, the first and second studs are positioned such that the two connecting rods 602, 604; 603, 605 (thus articulated on each jaw 631; 632) are elongated along parallel axes. The longitudinal axis of a connecting rod will be defined here as the axis which passes halfway through the thickness of the connecting rod and which intersects the axes of the first and second studs on which this connecting rod is articulated.

[0108] Each deformable parallelogram structure thus comprises: - a fixed side, formed by the housing and two of its first pads, - two sides mobile in rotation around the axes of these first pads, formed by the connecting rods, and - a mobile side in rotary translation formed by the jaw.

[0109] It is necessary for the two deformable parallelogram structures to act in concert on the sliding rod 531, that is to say that the jaws exert symmetrical stresses on this sliding rod 531.

[0110] For this, the movements of the two jaws 631, 632 are symmetrical and synchronized, here by means of gears 602a, 603a, 604a, 605a.

[0111] Different gear systems could be used for this purpose. In the example illustrated in [Fig.4], the solution consists of forming on the ends of the connecting rods 602, 603, 604, 605 teeth adapted to mesh.

[0112] The two connecting rods 602, 604 of one of the jaws then comprise several teeth meshing respectively with teeth of the two connecting rods 603, 605 of the other of the jaws. In this way, when a movement is imparted to one of the jaws 631, 632, this movement is mechanically transmitted to the other of the jaws.

[0113] Alternatively, other transmission means could have been used for the same purpose. Typically, it would be possible to use a connecting rod which would force the two jaws to move up or down in concert (according to the slide axis T).

[0114] Actuator

[0115] To move the jaws 631, 632 between their distal and proximal positions, the second operating means 60 advantageously comprise an actuator 601a, advantageously a bistable actuator, preferably associated with a timing member 601b, for example a spring box 601b.

[0116] The actuator 601a could comprise a manual operating lever.

[0117] Here, it is rather a controlled actuator.

[0118] This controlled actuator 601a preferably comprises a jack. It could be a electric or pneumatic cylinder, or even hydraulic.

[0119] In any case, it is a double-acting cylinder, allowing the jaws 631,632 to be moved:

[0120] - from the distal position to the proximal position, and

[0121] - from the proximal position to the distal position.

[0122] In practice, this jack comprises a cylinder which is mounted on a chassis.

[0123] Furthermore, the spring box 601b is in practice articulated on the housing 61 via a ball joint type connection.

[0124] The spring box 601b has a free end which is coupled:

[0125] - to one of the bits or

[0126] - to one of the connecting rods housed in this housing 61.

[0127] This free end is here articulated on one of the connecting rods 605 via a ball joint type connection.

[0128] Thus, the second operating means 60 are secured to only one of the deformable parallelogram structures, the other being actuated by the aforementioned gear system.

[0129] Generally and advantageously, the bistable actuator 601a translates the operator's instructions (package in lifting mode or package in passive swell compensation mode), which is “stored in memory” by the timing member 601b.

[0130] The execution, corresponding to the effective movement of the jaws, is conditioned by the safety conditions of the lifting operation:

[0131] - the controlled braking means 6 do not put the package into free fall even if the operator wants to switch to passive compensation; the controlled braking means 6 wait until the own weight has been taken up by the destination reference frame so that the jaws open at this precise moment, pushed “passively” by the timing member which has been pre-stressed by the change in position of the control;

[0132] - the controlled braking means 6 do not instantly block the movement of descent of the package even if the operator requests it; the jaws close, but on the safety ring which remains between the jaws until reaching the low point; once the package begins to rise, the safety ring is driven from the jaws and they rest on the sliding rod which is not blocked in the direction of the package's rise; when the package reaches its peak and wants to start to descend, the jaws block the movement of the sliding rod and thus the package rests at zero theoretical speed on the lifting cable(s).

[0133] In other words and advantageously, the controlled braking means 6 do not execute the operator's orders in real time but wait for the appropriate moments (those which ensure the safety of the operation) to do so. This is done in a passive, purely mechanical manner, that is to say by freeing itself from the management of sensors and actuators in real time, by the PLC or the operator. This approach makes it a solution where useful actions are naturally carried out at the right times and therefore in an intrinsically safe and reliable manner.

[0134] Adhesion friction cone

[0135] At this stage, it is possible to define more precisely how the second operating means 60 are designed in order to ensure that, in the proximal position, the jaws 631, 632 can block the sliding rod 531 if the latter tends to slide in one direction and that they allow it to slide if it tends to slide in the opposite direction.

[0136] To do this, it is necessary to define a “resultant angle” for each jaw.

[0137] This angle corresponds to the angle formed by the resultant of the forces applied by the jaws 631, 632 considered on the sliding rod 531. This resultant is composed of the bearing force of the jaw on the sliding rod, which is oriented parallel to the longitudinal axis of the connecting rods of this jaw, and the friction force of the jaw on the sliding rod, which is oriented parallel to the slide axis T.

[0138] It is also appropriate to define an angle at the apex of an adhesion friction cone, also called an "adhesion angle" or "friction angle".

[0139] The adhesion friction cone is formed by the boundary between the space in which the resultant of the forces is such that the sliding rod does not slide relative to the jaw 631, 632 (considering that the two jaws apply symmetrical forces on the sliding rod), and the space in which the resultant of the forces is such that the sliding rod 531 slides relative to the jaw 631, 632. Consequently, the adhesion angle corresponds to the maximum angle relative to a contact normal of the jaw on the sliding rod 531 in which a force can be applied by the jaw to the sliding rod 531 along the slide axis T without generating a translation of said sliding rod 531.

[0140] And the second operating means 60 are then configured such that, when the jaws 631, 632 are in the proximal position, said resultant angle is less than the friction angle, which blocks the sliding rod 531 in a fixed position in one direction.

[0141] In other words, the lifting system 1 is configured so that, when the jaws 631, 632 are in the active configuration, said resultant angle is less than the angle at the apex of the adhesion friction cone, advantageously less a safety margin. For example, at 0.15 friction / adhesion coefficient, the minimum requirement is 9°. The effortless angle is taken at 8° and will decrease with the increase in load.

[0142] It is therefore possible to play on several parameters.

[0143] A first parameter is the force exerted by the actuator 601a on the jaws. However, here, this force is intended to remain restricted compared to the other forces in game.

[0144] A second parameter, at least as important as the first, is the angle a ([Fig.4]) formed, in the proximal position, between the longitudinal axis of any one of the connecting rods and the normal to the jaw (in particular normal to its friction face 631a, 632a) on which this connecting rod is articulated. The smaller this angle a is when the jaws 631, 632 are in the proximal position, the more the connecting rods 602, 603, 604, 605 are perpendicular to the friction faces of the jaws.

[0145] The objective is then to adjust this angle a as a function of the coefficient of adhesion friction between the friction faces 631a, 632a of the jaws and the sliding rod 531.

[0146] Here, the jaws 631, 632 being made of soft stainless steel (for example of the 316L type) and the sliding rod 315 being made of hard stainless steel (for example of the Super-Duplex X2CrNiMoN 25-7-4 type), the coefficient of friction of adhesion between these two materials is between 0.15 and 0.2. Therefore, an angle a of 8° makes it possible to retain the sliding rod 531 when the load C has a substantially zero weight. As explained above, when the weight of the load C increases, the sliding rod 531 tends to slide in the direction of the reduction of the distance dimension D, which causes the jaws 631, 632 to be tightened by friction, so that the rod remains blocked despite this increase in load.

[0147] Thus, by geometrically imposing an angle a smaller than that of the natural friction cone of adhesion that exists between the jaws and the sliding rod at zero load, the load C will remain retained when the jaws are closed, whatever its mass. This is a virtuous system because it is the very presence of the load C which creates its retention. Conversely, this system allows free movement of the sliding rod 531 in the other direction, when the load C rises. Indeed, in this case, the jaws are pushed by friction to open.

[0148] Of course, the materials of the jaws and the sliding rod could be different, in which case the angle a would have to be modified according to the coefficient of friction of adhesion between the chosen materials.

[0149] For example, we can consider that, for an adhesion friction coefficient of between 0.08 and 0.16, the angle can be between 5° and 9°.

[0150] Of course, for a coefficient of greater value (for example if the jaws are coated with rubber), the angle a may have a higher value.

[0151] Mechanical stops

[0152] When the jaws 631, 632 have been closed in the proximal position and the weight of the load C is high, the sliding rod 531 causes a displacement of the jaws beyond their proximal position (relative to the distal position), by elastic breathing of the parts in compression (connecting rods, jaws, bearing) and in traction (casing).

[0153] All of the controlled braking means 6 could be oversized to withstand loads greater than the recommended maximum, so as to withstand unexpected shocks and stresses. However, this solution would prove to be much less interesting technically and economically.

[0154] Here, the aim is rather to avoid that if the weight of the load C exceeds a recommended load threshold (for example including dynamic effects such as maximum accelerations imposed on the lifting machine or shock effects due to the recovery of the lifted load at too high a relative speed (accidental presence of slack), the stresses exerted by the sliding rod 531 on the various components of the controlled braking means 6 (housing, connecting rods and jaws) are too high and cause damage to one of these components.

[0155] For this, as shown in [Fig.3], the controlled braking means 6 comprise mechanical stops 641, 642 making it possible to define an end-of-travel position for the jaws 631, 632.

[0156] This end-of-travel position is chosen so that, when the jaws are in this position, the angle a remains strictly greater than 0. Thus, this angle a varies here from a value strictly greater than 8° in the distal position, to a value between 0 and 8° (limits excluded) in the end-of-travel position.

[0157] Here, these mechanical stops 641, 642 are adjustable, which makes it possible to adjust in situ the end-of-travel position and thereby the limit force capable of being retained by the jaws. This is a precise, passive force limitation system with a very good level of repeatability. Having reached the full stop, the direction of the resistance of the forces of the jaws on the sliding rod is very significantly affected. Initially imposed by the direction of the connecting rods, the path of the forces being much steeper by the stops, the slightest increase in force on the sliding rod tends to bend the resultant towards the axis of the sliding rod, which causes it to very quickly leave the cone of friction of adhesion and thus initiates a sliding of the sliding rod under the jaws which stops naturally as soon as the force has returned below the preset threshold. This solution thus ensures the role of force limiter, like a mechanical safety valve.

[0158] In the embodiment illustrated in [Fig.3], these are screws, having the advantage of being able to carry out recalibration if necessary. It could also be a simple fixed height stop (calculated in advance).

[0159] As illustrated in this figure, these screws can be screwed into the jaws 631, 632, in order to come into contact with the housing 61 when the jaws reach the end-of-travel position.

[0160] Alternatively, these screws could be screwed into the housing 61, to form stops into contact with which the jaws would come when the latter arrived in position. end of race.

[0161] Other structures could be considered.

[0162] Typically, the stop means could comprise only a single screw placed on any one of the jaws, the gears ensuring the symmetrical stopping of the other of the jaws in the end-of-travel position.

[0163] It is understood that if the weight of the load C is very high, the jaws will come to bear against these mechanical stops 641, 642, so that the resultant of the forces will come out of the cone of friction of adhesion. Thus, in this case, the jaws 631, 632 are no longer able to retain the sliding rod 531 in the direction of the reduction of the dimension in distance D.

[0164] Consequently, in the event of an impact causing a sudden and time-limited increase in the weight of the load C, the load C may drop somewhat, which will prevent all of the stresses from being transmitted to the controlled braking means 6 and plastically deforming them.

[0165] Safety ring

[0166] Preferably, safety means are also provided to prevent the jaws 631, 632 from coming into the proximal position in a particular situation:

[0167] - the jaws are in the distal position, and

[0168] - the jaws are commanded to come into the proximal position while the efforts applied to the sliding rod 531 tend to a reduction in the distance dimension D.

[0169] In other words, the safety means prevent the jaws from being pressed against the sliding rod 531 when a load C is held by the cable and the load C undergoes a downward movement (for example when the destination reference frame Rd on which the load is placed descends relative to the original reference frame Ro). Such a technical characteristic prevents the load C from being suspended mid-wave on the falling front (where the relative speed is maximum, which would generate a potentially destructive dynamic force), and the load from being struck shortly after by the destination reference frame Rd when the latter rises on the next wave.

[0170] Preferably, these safety means are designed to automatically interpose themselves between the jaws 631, 632 when the latter are in the distal position and the distance dimension D decreases.

[0171] Here, as shown in [Fig.3], these safety means comprise a safety ring 65 which surrounds the sliding rod 531.

[0172] This safety ring 65 is housed inside the housing 61 and is threaded (or fitted) onto the sliding rod 531 so as to be able to slide on the latter between two distinct extreme positions, called the active position and the inactive position.

[0173] According to the illustrated embodiment, it is located here opposite the means of stop 641, 642 relative to jaws 631, 632.

[0174] In the active position, the safety ring 65 is designed to be interposed between the jaws in order to prevent the actuator 601a from returning these jaws to the proximal position.

[0175] In the inactive position, the safety ring 65 is located at a distance from the jaws so as not to obstruct their movement.

[0176] The safety ring 65 is mounted on the sliding rod 531 so as to:

[0177] - on the one hand, be held in a fixed position on the latter when no effort exerts on this ring, and

[0178] - on the other hand, to be able to slide along the sliding rod 531 when the rod sliding 531 slides and the ring comes into abutment against the housing 61 or against the jaws.

[0179] The safety ring 65 then has an oscillating stroke defined between the housing 61 and the jaws.

[0180] As shown in [Fig.3], the jaws 631, 632 each have a notch on the side of the safety ring 65. These notches together delimit a cavity 650 open towards the sliding rod 531 and on the opposite side of the sliding ring 65.

[0181] Then, the safety ring 65 is designed to be able to be housed in this cavity 650 only when the jaws are in the distal position and the sliding rod 531 has a movement tending towards a reduction in the distance dimension D.

[0182] If the jaws are in the proximal position and the rod slides in the same direction (for example because the load C is too great and the jaws are in the end-of-travel position), the safety ring 65 comes to bear against the edges of the jaws so that it cannot be housed in the cavity 650. It thus remains inoperative.

[0183] If the sliding rod 531 exhibits a movement tending towards an increase in the distance dimension D, the safety ring 65 comes to bear against a side wall of the housing 61. It thus remains inoperative.

[0184] This safety ring 65 is shown in detail in [Fig.5].

[0185] It has internal and external faces that are substantially cylindrical around an axis of revolution Al, and extends over a height less than the distance separating the jaws and the aforementioned side wall of the housing 61.

[0186] According to a particular embodiment, it advantageously comprises three substantially identical sections 651, each extending over an angular sector of 120°. These three sections 651 are articulated to each other, around pivot axes parallel to the axis of revolution AL.

[0187] A first of the sections 651 is further secured to a second of these sections via an elastically deformable connection, which makes it possible to slightly separate these two sections so as to modify the diameter of the safety ring 650.

[0188] In practice, this first section has a hollow cavity 652 in its face external, and a hole which opens on one side into this cavity, and on the other at the end of the first section which faces the corresponding end of the second section. A screw 653 is engaged in this hole so that its head is housed in the cavity 652 and its threaded body is screwed into a tapped bore provided in the second section. A compression spring 654, which is sandwiched between the head of the screw 653 and the edge of the hole, makes it possible to elastically return the safety ring into a tightened configuration where its diameter is minimal.

[0189] Thus, the safety ring 65 can have a variable diameter, between the aforementioned tightened configuration and an enlarged configuration in which its diameter is maximum.

[0190] The inner face of the safety ring 65 has, in the tightened configuration, a diameter strictly less than that of the sliding rod 531, and, in the enlarged configuration, a diameter strictly greater than that of the sliding rod 531.

[0191] Thus the safety ring 65 remains in contact around the sliding rod 531, which allows it to slide with the latter as long as it is not in contact with the housing 61, nor with the jaws 631, 632. The stiffness of the compression spring 654 is sufficiently low so that the friction between this ring and the rod remains restricted and that, when the safety ring 65 comes to bear (for example against the housing 61), it does not hinder the sliding of the sliding rod 531.

[0192] In summary, the bistable command executed by the actuator 601a makes it possible to place the jaws 631, 632 in three positions, namely:

[0193] - the proximal position, in which the jaws 631, 632 are supported on the neck rod smoothing 531, controlled by the second operating means 60,

[0194] - the distal position, in which the jaws are at a distance from the sliding rod 531, controlled by the second operating means 60, and

[0195] - an intermediate position, in which the jaws 631, 632 are controlled for move to a proximal position from a distal position but the safety ring 65 locks these jaws in an intermediate position between the distal position and the proximal position.

[0196] In other words, in the intermediate position, the jaws do not reach the proximal position. The sliding rod 531 is able to slide within the controlled braking means 6.

[0197] Furthermore, preferably, the safety ring 65 is ejected relative to the jaws 631, 632 in the intermediate position when these jaws are driven from the intermediate position to the distal position.

[0198] In other words, once the jaws are placed on the safety ring:

[0199] - in the direction of descent of the package (reduction of the distance D), the ring of safety remains between the jaws, sucked in by the sliding of the sliding rod,

[0200] - in the direction of the package's ascent (increase in distance D), the ring of safety is naturally ejected from the jaws (aided by a conical shape given to the jaw / safety ring interface) which then fall back onto the sliding rod

[0201] Means of maneuver

[0202] The first operating means 8 cooperate with said mobile block of sheave(s) 52.

[0203] These first maneuvering means 8 are configured to restore energy po potential on the mobile block of sheave(s) 52 so: - in the inactive configuration, to strive to maintain a constant tension in said at least one lifting cable (thus achieving passive compensation for the swell), and - in active configuration, to strive to increase the distance rating D.

[0204] More precisely, these maneuvering means 8 are configured to accumulate the potential energy coming from the mobile block of sheaves 52 when the distance dimension D decreases.

[0205] In other words, the operating means 8 are intended to restore a restoring force, corresponding to the restored potential energy.

[0206] The operating means 8 are adapted to maintain sufficient tension to tighten said at least one lifting cable 3, in the inactive configuration and in the active configuration of the controlled braking means 6.

[0207] Without being limiting, this tension advantageously depends on the maximum length of said at least one lifting cable 3 which hangs during passive compensation of the hoe, on the linear density of said at least one lifting cable 3 and on the value of the destabilizing forces (for example winds, accelerations of the reference frames) which tend to cause said at least one lifting cable 3 to come out of its / their ideal natural position(s) of straightness between the sheaves 51, 52 and the fixed points.

[0208] Preferably, this tension must also be greater than the force exerted by the controlled braking means 6 in the active configuration, in the direction of increasing the distance dimension D.

[0209] By “potential energy”, we preferably include: - elastic potential energy, for example in the form of a spring member (not shown), advantageously mechanical or pneumatic, and / or - gravitational potential energy (called gravity), for example in the form of a counterweight.

[0210] For example, a spring member accumulates elastic potential energy (for example by being stressed) when the distance dimension D decreases.

[0211] In the same way, a counterweight accumulates gravitational potential energy (for example by its displacement in height) when the distance dimension D decreases.

[0212] Generally speaking, the counterweight can possibly be formed by: - the sliding beam 531, and / or - an offset counterweight 85, suspended from one end of the sliding spar 531 (for example at a proximal end, on the side of the winch 4), directly ([Fig.3]) or via a cable / pulley assembly, and advantageously exerting a traction force on the sliding spar 531.

[0213] Conversely, the potential energy is here restored in the form of a restoring force, by the increase in the distance dimension D.

[0214] Generally speaking and taking into account the operating means 8 exerting potential energy on the mobile block of sheave(s) 52, the distance dimension D is notably variable depending on the traction force exerted by the package C via the lifting cable 3: - the distance rating D tends to increase when the traction force exerted by the package C decreases, and - the distance dimension D tends to decrease when the traction force exerted by the package C increases.

[0215] In other words, the movements of the mobile block of sheave(s) 52 are determined by: - ​​the traction force exerted by the package C on the lifting cable 3, - the return force corresponding to the potential energy restored by the maneuvering means 8, - the friction forces exerted by the jaws 631, 632, and - and where applicable, the turning and de-turning maneuvers carried out on the lifting cable 3 via the winch 4.

[0216] Control means

[0217] The control means 7 are configured for controlling the winch 4 and possibly the controlled braking means 6, in particular during the operation of launching or recovering the package C.

[0218] Such control means 7 comprise, for example, a computer program implemented by a computer, for example in the form of an industrial programmable logic controller. This computer program advantageously comprises instructions which, when the program is executed by a computer, cause the latter to control the winch 4 and / or the controlled braking means 6 (preferably according to an algorithm).

[0219] Preferably, the control means 7 advantageously comprise a centering module 71 which, in the inactive configuration of the controlled braking means 6, is configured to control the winch 4 so as to position the mobile block of sheave(s) 52 in a centered position, advantageously an average position centered on an available stroke.

[0220] This centering module 71 advantageously comprises an initial centering module 71a, which aims to position the mobile block of sheave(s) 52 in a pre-centered position. possibly to an operation of launching package C from a repository.

[0221] The centering module 71 also advantageously comprises a slow centering module 71b which is configured so that, in the inactive configuration of the controlled braking means 6, it tends to maintain the mobile block of sheave(s) 52 in a centered position, advantageously an average position centered on an available stroke.

[0222] Preferably, the slow centering module 71b cooperates with means for instantaneous and averaged measurement of the position of the mobile block of sheave(s) 52 over a period of time (period of 30 s to 90 s for example), in particular when the controlled braking means 6 are in the inactive configuration.

[0223] The means for instantaneous and averaged measurement of the position of the mobile block of sheave(s) 52 consist for example of a cable or laser position sensor.

[0224] This slow centering module 71b is configured to control the winch 4 (turning and unturning) when the average position of said mobile block of sheave(s) 52 reaches one or other of two actuation thresholds along the slide axis T.

[0225] Preferably, the control means 7 advantageously comprise an end-of-travel safety module 72, which is configured to actuate the winch 4 (turns and unturns) when the mobile block of sheave(s) 52 reaches one or other of two end-of-travel thresholds along the slide axis T.

[0226] Preferably, an increasing speed order is imposed by this end-of-travel safety module 72 to prevent the mobile block of sheave(s) 52 from reaching the end of the travel.

[0227] Still preferably, the control means 7 comprise an automatic recovery module 73 and / or an automatic launch module 74, configured to automatically control the winch 4 and the controlled braking means 6 during the recovery operation and / or the launch operation of the package C, in the manner described below.

[0228] The automatic recovery module 73 and / or the automatic launch module 74 is preferably associated with at least one measurement sensor 75 (for example a laser or a radar, illustrated in [Fig.l]) configured to measure the relative vertical distance between a frame of reference of the chassis 2 and a destination frame of reference, for example in the case where the average distance between the frame of reference of the chassis 2 and the destination frame of reference is not known or variable.

[0229] Preferably, said at least one measurement sensor 75 makes it possible to measure the relative vertical position of the destination reference frame with respect to the lifting system 1, among: - the average position, - the highest position, - the lowest position.

[0230] From these measurements, it is possible to determine: - the instantaneous vertical speed (by AU / At derivation), - the maximum speed uphill and downhill (over the last 1 to 5 minutes for example), - the average absolute speed (over the last 5 minutes, for example), - the length to be unwound by winch 4 to obtain the centering of the mobile block of sheave(s) 52 in the theoretical centered position.

[0231] First embodiment

[0232] As illustrated in [Fig.l], the lifting system 1 consists of a crane having a single lifting point 1a.

[0233] In this case, the frame 2 comprises an upright 2a and an arrow 2b.

[0234] Generally speaking, the winch 4, the hauling means 5, the controlled braking means 6 and the maneuvering means 8 are advantageously carried by the chassis 2.

[0235] According to the embodiment illustrated in Figures 1 and 2, the winch 4 and the hauling means 5 are carried by the upright 2a. In particular, the fixed sheave block 51 is articulated at the top of the upright 2a, and the slide means 53 define a degree of freedom in translation having a vertical slide axis T, along this upright 2a, so that the movable sheave block(s) 52 extends under the fixed sheave block 51, at a distance from the latter corresponding to the distance dimension D.

[0236] From then on, the lifting cable 3 extends from the winch 4 to the hauling means 5, then returns horizontally to a pulley carried by the boom to descend towards the load C.

[0237] The first operating means 8, cooperating with the mobile block of sheave(s) 52, here use gravitational potential energy. In this mode, they comprise a counterweight formed partly by the sliding spar 531 and partly by a mass fixed to this sliding spar 531.

[0238] Alternatively, these maneuvering means 8 could comprise an offset counterweight (not shown), exerting downward traction on the sliding spar 531.

[0239] Of course, as a variant, a spring member could have been used.

[0240] As shown in [Fig.3], in this first embodiment, the pivot axes connecting rods 602, 603, 604, 605 therefore extend horizontally, while the friction faces 631a, 632a of the jaws 631, 632 rise vertically.

[0241] Due to this orientation, it is necessary to compensate for the weight of the jaws 631, 632. This compensation could be carried out actively, by the actuator 601a. ​​But preferably, it is carried out passively, here by a spring 80 which pushes the jaws upwards (the force exerted by the spring counteracting the weight of the two jaws). Alternatively, a counterweight system could be used.

[0242] In this first embodiment, the housing 61 has two opposite openings crossed by the sliding rod 531. To guarantee the correct sliding of this rod, These openings can be equipped with sliding rings, such as bronze or copper-aluminum rings.

[0243] Second embodiment

[0244] In a second embodiment illustrated in Figures 7 and 8, the slide means 53 define a degree of freedom in translation of the horizontal slide axis T.

[0245] In practice, in this mode, the lifting system 1 could consist of a crane, in which case the winch 4 and the hauling means 5 would be carried by the boom. It will be considered here that it consists rather of a gantry comprising at least two identical lifting points (only one of which is shown in the figures). In this mode, the winch 4 and the hauling means 5 are carried by a horizontal crosspiece 2b of the gantry.

[0246] In any case, as shown in [Fig.7], the winch 4 (here comprising two counter-rotating motors), the hauling means 5, and the controlled braking means 6 are advantageously carried by the horizontal crosspiece 2b.

[0247] As illustrated in [Fig.7], the fixed block of sheaves 51 is located at a distance from the winch 4, and the mobile block of sheaves 52 is located between the fixed block of sheaves 51 and the winch 4. Of course, the opposite would be possible.

[0248] The controlled braking means 6 are located on the other side of the winch 4 relative to the hauling means 5.

[0249] As shown in [Fig.8], the sliding rod 531 therefore passes through the fixed block of sheaves 51 so as to be able to be fixed to the mobile block of sheaves 52 and to be able to pass through the housing 61 of the controlled braking means 6. This sliding rod 531 is carried by support rollers 532, so as to be able to slide horizontally (as freely as possible, advantageously without friction). Here, one roller is located on one side of the housing 61 (the side opposite the sheaves) and the other roller is located on the other side of the mobile block of sheaves 52. These rollers can be formed by rollers mounted on bearings or by any other ad hoc system.

[0250] Thus, in this second embodiment, the lifting cable 3 extends from the winch 4 to the hauling means 5, then descends towards the load C directly from the fixed block of sheaves 51.

[0251] The maneuvering means 8, cooperating with said mobile block of sheave(s) 52, here again use gravitational potential energy, for example in the form of a counterweight (not shown) offset intended to exert a traction force on the sliding spar 531 oriented horizontally, for example via a cable and pulley system.

[0252] In this embodiment, the pivot axes of the connecting rods 602, 603, 604, 605 of the controlled braking means 6 extend vertically, while the friction faces of the jaws extend horizontally. Due to this orientation, it is not no need to compensate for the weight of the bits.

[0253] Lifting method

[0254] At this stage, the operation of the lifting system 1 can be described in detail, with particular reference to [Fig.6].

[0255] - Passive swell compensation

[0256] We speak of “passive swell compensation” when the lifting system 1 and the package C rest on two different reference frames (the original reference frame Ro and the destination reference frame Rd).

[0257] In this configuration illustrated by vignette VI in [Fig.6], the control means control the controlled braking means 6 in the inactive configuration. In practice, the actuator 601a exerts a force F1 on the jaws 631, 632 to maneuver them into the distal position.

[0258] The mobile block of sheave(s) 52 is then subjected to two inverse forces: - the tensile force exerted by package C via lifting cable 3, and - the restoring force corresponding to the potential energy restored by the first operating means 8.

[0259] The resultant F2 of these forces varies in the following manner.

[0260] If the difference in height between the reference frames decreases (for example a wave causes the package C to rise), the tension in the lifting cable 3 decreases and, naturally, the distance dimension D increases under the action of the first operating means 8.

[0261] Conversely, if the height difference between the reference frames increases (for example a wave causes the package C to descend), the tension in the lifting cable 3 increases and, naturally, the distance dimension D decreases.

[0262] Passively, the lifting cable 3 is advantageously maintained at an average tension (namely preferably a force exerted by the maneuvering means 8 divided by the number of strands of the hauling means 5).

[0263] Preferably, in passive compensation for the swell, the method comprises a step of controlling the winch 4 to tend to maintain the mobile block of sheave(s) 52 in an average position.

[0264] This centering of the mobile block of sheave(s) 52 is ensured here by the aforementioned slow centering module 71b.

[0265] In practice, if an actuation threshold is reached by increasing the distance dimension D, the slow centering module 71b controls the winch 4 in a turn so as to tend to bring back, advantageously on average, the mobile block of sheave(s) 52 into a central position.

[0266] Conversely, if an actuation threshold is reached by reducing the distance dimension D, the slow centering module 71b controls the winch 4 in such a way as to tend to bring back, advantageously on average, the mobile block of sheave(s) 52 into a position central.

[0267] Generally, if an end-of-travel threshold is reached, the end-of-travel safety module 72 is executed to actuate the winch 4, turning or deflecting as appropriate, so as to actively push the mobile block of sheave(s) 52 back relative to said end-of-travel threshold.

[0268] - Launch

[0269] The present invention also relates to the method for lifting a package C, in particular for lifting a package C in the presence of a relative movement due to swell, by implementing a lifting system 1 according to the invention.

[0270] It thus firstly concerns an operation of launching the package C from the original reference frame Ro to the destination reference frame Rd, in which case the lifting process advantageously comprises several successive steps.

[0271] These steps can be controlled one after the other manually (using a human-machine interface for example) or on the contrary in a fully automated manner. Alternatively, it would also be possible to provide a semi-automated control, in which certain steps would be implemented manually while others would be carried out automatically. Here, this launch operation is ensured by the automatic launch module 74.

[0272] Initially, the package is placed on the original reference frame Ro and is attached to the lifting cable 3. The operation is then initiated by an operator who presses an ad hoc button connected to the automatic launch module 74.

[0273] The first step consists of ensuring that the jaws are in the distal position and placing, using the winch, the mobile block of sheave(s) 52 in an average position centered on an available stroke.

[0274] According to a preferred embodiment, during a second step, the winch 4 is controlled to perform a turning and then unturning movement, in order to place the safety ring 65 in the inactive position, against the wall of the housing 61, outside the cavity 650 delimited by the jaws.

[0275] During a third step, the controlled braking means 6 are controlled in active configuration. In practice, the actuator 601a exerts a force F1 on the jaws 631, 632 to bring them into the proximal position and keep them there. At this step, the safety ring 65 does not prevent the jaws 631, 632 from coming to bear against the sliding rod 531.

[0276] Then, during a fourth step, the winch 4 is commanded to turn to lift the package C above the destination reference frame Rd (thumbnail V2 in [Fig.6]). The force exerted by the jaws on the rod will then be all the greater as the weight exerted by the package C on the lifting cable 3 is important, which is illustrated by the resultant of the forces F2.

[0277] At the end of this step, the lifting system can then possibly be commanded to move the package C to the destination repository Rd.

[0278] During a fifth step, the package C is lowered close to the destination reference frame Rd, preferably so that the package reaches this reference frame when the difference in heights between the reference frames is minimal (for example close to the highest wave crests of the swell).

[0279] Thus, the winch 4 is controlled to deviate, for example near a wave crest at the end of a rising front, preferably so that the package C lands on the destination reference frame Rd and descends at the same speed as the latter (to come to a tangent to the wave crest). Thus accompanying a downward movement of the destination reference frame Rd makes it possible to minimize the shocks (namely the accelerations) perceived by the package C.

[0280] A sixth step of controlling the controlled braking means 6 in the inactive configuration is then provided. In practice, this sixth step can be implemented during, or even before, the fifth step (but after the fourth step). Its implementation is therefore not constrained from a time point of view.

[0281] Indeed, this sixth step of switching the controlled braking means 6 to the inactive configuration is not necessarily executed immediately: it is only executed when a condition is met. It is then said to be put on hold (or in memory). The suspensive condition relates to the force applied by the package C to the sliding rod 531. When this force is greater than a predetermined threshold (relating to the presence of a package suspended by the cable which it is desired to prevent from falling in free fall), the step is put on hold. Indeed, as shown in vignette V3 of [Fig.6], the resultant F2 of the forces applied to the sliding rod 531 cannot be countered by the force Fl exerted by the actuator 601a to open the jaws, so that the latter remain closed in the proximal position.This sixth step is, however, executed as soon as the resultant F2 decreases below a threshold (which reflects the fact that the package C is now placed on the destination reference frame Rd). Indeed, as shown in vignette VI of [Fig.6], the resultant F2 of the forces then applied to the sliding rod 531 can be countered by the force Fl exerted by the actuator 601a to open the jaws, so that the latter open in the distal position.

[0282] Thus, the jaws 631, 632 only open when the weight of the package C has been transferred to the destination reference frame Rd.

[0283] When said package C thus transfers its weight from the lifting cable 3 to the destination reference frame Rd, said lifting system 1 ensures passive compensation for the swell, as explained above.

[0284] - Recovery

[0285] The present invention also relates to an operation of recovering the package C in order to bring it back from the destination reference frame Rd to the origin reference frame Ro, in which case the lifting method advantageously comprises several successive steps.

[0286] Here again, these steps can be controlled one after the other manually or on the contrary in a fully automated manner, or even in a semi-automated manner. Here, this recovery operation is carried out by the automatic recovery module 73.

[0287] Initially, the package is placed on the destination repository Rd and is attached to the lifting cable 3. The operation is then initiated by an operator who presses an ad hoc button connected to the automatic recovery module 73.

[0288] Starting from an inactive configuration as mentioned above in which said lifting system 1 provides passive compensation for the swell, the lifting method firstly comprises a step of controlling the controlled braking means 6 to switch them to the active configuration, so that the jaws sandwich the sliding rod 531.

[0289] In practice, as shown in vignette V4 in [Fig.l], the actuator 601a exerts a force F1 on the jaws 631, 632 to bring them towards the proximal position.

[0290] The step of switching the controlled braking means 6 to the active configuration is not necessarily executed immediately: it is only executed when a condition is met. It is then said to be put on hold (or “in memory”). The suspensive condition this time relates to the direction of movement of the package C. When the distance dimension D decreases (the package is descending), the step is put on hold. The command is, however, executed as soon as the distance dimension D increases. It may therefore happen that it is executed immediately if at the time of the command, this dimension was increasing.

[0291] This suspension could be carried out by the control means. However, here, it is advantageously carried out by the safety ring 65 which, when the jaws are in the distal position and the distance dimension D decreases, is placed between the jaws 631, 632, in the cavity 650. The control of the jaws in the proximal position cannot therefore be carried out since the jaws abut against this safety ring 65. On the other hand, as soon as the distance dimension D increases, the safety ring 65 is ejected which allows the jaws to reach the proximal position.

[0292] It will be noted that when the safety ring 65 is interposed between the jaws 631, 632, it exerts low-intensity friction forces on the traction rod 531, which do not prevent the latter from sliding in the housing 61 provided that the weight of the package C is not zero.

[0293] In other words, the order is not executed as long as package C follows a downward movement because this would have the possible double consequence, in the worst case, at the maximum relative speed, in the middle of the wave:

[0294] - at the moment, to generate a dynamic effect potentially generating damage to the lifting equipment and the package, and

[0295] - in the next wave, to generate a collision of the destination reference frame Rd under the package, if an immediate and high-speed turning action was not initiated, potentially damaging to the package (but not damaging to the lifting equipment).

[0296] When the command is executed (thumbnail V5 in [Fig.6]), the jaws 631, 632 come to bear against the sliding rod 531. The package C following an upward movement, the jaws do not block the sliding rod 531 and the mobile block of sheave(s) 52 continues its movement by increasing the dimension in distance D. Once arrived at the crest of the wave, the controlled braking means 6 on the other hand prevent the reduction of the dimension in distance D. The start of the descent of the next wave then gradually deposits the package C on the lifting cable 3. At the end, the package C hangs at the end of the lifting cable 3, above and at a distance from the destination reference frame Rd.

[0297] Then, or even before the wave crest, the winch 4 is controlled to turn. Preferably, it is controlled to turn as soon as the jaws 631, 632 reach their proximal position, with constant acceleration up to a predetermined speed setting. The movement of the sliding rod 531 will then follow the speed difference between what the environment imposes (recovery of slack) and what the winch 4 will absorb (which will on the contrary tend to reduce the distance dimension D).Thus, for example during the “mid-wave” phase where the speeds imposed by the environment are greater than the lifting speed by the winch 4 alone, the sliding rod 531 will continue to recover the slack but, upon reaching the wave crest, the rewinding speed of the winch 4 will exceed the lifting speed of the package C and therefore the sliding rod 531 will find itself blocked by the jaws 631, 622 and the package C will therefore gradually transfer its weight onto the lifting cable 3.

[0298] In all cases, the relative speed of the package C with respect to the original reference frame Ro at the time of the load transfer from the destination reference frame Rd to the lifting cable 3 is strictly zero. This is a major advantage of the lifting system 1 and its control method since it minimizes the dynamic lifting coefficient (unlike a conventional lifting machine which will inevitably experience at some point during its operation a shock with a relative speed much higher than 0 m / s). The constraints exerted on the system being thus reduced, it is possible to size it accordingly, to the benefit of its weight, its size and its cost.

[0299] If a higher wave crest arrives later, package C risks rest on the destination reference frame and rise again under the effect of this wave. In this event, the sliding rod 531 remains free to slide between the jaws, so that the package C does not descend again and is blocked at a new maximum level.

[0300] Package C is then brought back above the original reference frame Ro, then lowered using winch 4 towards the original reference frame Ro.

[0301] At this stage, some observations can be made about this recovery operation.

[0302] The first observation is that if the waves are very small, the safety ring 65 might not move into the active position. To avoid this, a slight deflection instruction could be applied at the same time as the closing instruction of the jaws 631, 632. In this case, the relative speed of the package C with respect to the original reference frame Ro at the time of the load transfer could reach at most the value of the deflection speed.

[0303] The second observation is that the lifting system 1 as designed makes it possible to control the closing of the jaws 631, 632 in the proximal position at any time during the recovery operation, due to the presence of the safety ring 65. Of course, to make the system capable of continuing operations after a fault, it remains preferable to start the recovery operation in a “wave trough”. But if the operation accidentally starts at another time, this will have no impact on the safety of the operation thanks to the safety ring.

[0304] The third observation is that slack in the lifting cable 3 and “external play” may appear not due to the lifting system 1 itself, but due to the load C. To understand this, we can consider that the lifting system 1 comprises four lifting points 1a, and therefore four lifting cables 3 which carry straps in pairs for lifting a floating device. This device, typically a boat, is then piloted to position itself above the two straps, and these straps are then designed to be raised by the four lifting points. Then, when the jaws 631, 632 close, the cradle formed by the two straps is at zero speed and the floating device must sit in the straps before being lifted. Thus, the cradle will be recovered and will gain speed relative to the floating device, so that a residual shock will occur when the boat sits in the straps.Minimizing slack and external play will minimize relative speed and therefore related dynamic effects.

[0305] The fourth observation is that the end-of-travel stops having a force limiter function, in the event of malfunction or departure from the specified environmental conditions (or in the event of significant external play), the rod will slide between the jaws which will limit the dynamic effects induced beyond a certain threshold. From this In this way, none of the components of the lifting system 1 will be damaged.

[0306] The fifth observation is that in the event of a power supply failure: - to compensate for the swell: the lifting system 1 being passive, it continues to operate normally; - when lifting: if package C is close to a reference frame and if this reference frame comes back into contact with package C, then the latter rises to the new highest point which will prevent it from hitting this reference frame several times.

[0307] The sixth observation is that the lifting system 1 presented, due to its simple and highly mechanized architecture, has a very low reaction time. This reaction time will preferably be less than 4 tenths of a second when it comes to opening or closing the jaws (i.e. less than one tenth of the minimum wave period).

[0308] Variant

[0309] Of course, various other modifications may be made to the invention within the scope of the appended claims.

[0310] Typically, the lifting system 1 could comprise several pairs of jaws housed in the same housing, preferably all controlled by the same actuator. These pairs of jaws could be distributed in a cross around the sliding rod, or in a superimposed manner along the sliding rod.

[0311] According to another variant, it would be possible to envisage operating means different from those described and shown (deformable parallelogram systems) but allowing that, when the jaws are in the proximal position, they block the sliding of the sliding rod 531 in one direction only. Typically, the sliding rod and the jaws could be covered with saw-tooth notches which would push the jaws outwards when the sliding rod tends to move in one direction and which would, on the contrary, compress the jaws against the sliding rod when the latter tends to move in the opposite direction. According to another variant, the jaws could be pushed against the sliding rod by jacks inclined relative to the axis of the rod.

[0312] According to another variant of the invention, the safety means could comprise, instead of the safety ring 65, a sensor making it possible to detect the direction in which the sliding rod moves and to control the jaws accordingly. The solution illustrated in the figures is however more robust than a solution based on such a sensor.

Claims

Claims

1. Lifting system (1) for a package (C), preferably between two reference frames (Ro, Rd) having at least one relative vertical movement, for example for lifting the package (C) in the presence of a relative movement due to swell, which lifting system (1) comprises at least one lifting point (la) which comprises a chassis (2) comprising: - at least one lifting cable (3) associated with: — a winch (4), for maneuvering said lifting cable (3), in turns and out turns, — hauling means (5) comprising: — a fixed block of sheaves (51), secured to said chassis (2), and — a movable block of sheaves (52), cooperating with said chassis (2) by means of sliding means (53) defining a degree of freedom in translation orthogonally to axes of rotation (51', 52') of said blocks of sheaves, the distance dimension (D) of said movable block of sheaves (52) relative to said fixed block of sheaves (51) being variable, - controlled braking means (6), cooperating with said mobile block of sheaves (52) and controllable between two preferably bistable configurations: — an inactive configuration, in which said controlled braking means (6) allow free translation of said mobile block of sheaves (52) according to said degree of freedom in translation, in particular adapted to passive compensation of swell, and — an active configuration, in which said controlled braking means (6) allow the moving block of sheave(s) (52) to move in a single direction according to said degree of freedom in translation, corresponding to an increase in said distance dimension (D), - control means (7), for controlling said winch (4) and said controlled braking means (6), in particular during the operation of launching or recovering said package (C), - first operating means (8) which cooperate with said mobile block of sheaves (52) and which are configured to restore potential energy to said mobile block of sheaves (52) so that: — when said controlled braking means (6) are in the inactive configuration, to tend to maintain a constant tension in said at least one lifting cable (3) and, — when said controlled braking means (6) are in configuration active, to tend to increase said distance dimension (D), characterized in that said sliding means (53) comprise a sliding rod (531) which carries the movable block of sheave(s) (52), which is guided in translation coaxially with said degree of freedom in translation and which cooperates with said controlled braking means (6), and in that said controlled braking means (6) comprise: - at least two jaws (631, 632) which are distributed around said sliding rod (531), which jaws (631, 632) each comprise a friction face (631a, 632a) adapted to cooperate with said sliding rod (531), - second bistable operating means (60) adapted to move each jaw (631, 632) between two positions: — a distal position, at a distance from said sliding rod (531), corresponding to said inactive configuration of said controlled braking means (6), and — a proximal position, resting on said sliding rod (531), corresponding to said active configuration of the controlled braking means (6).

2. Lifting system (1) for a package (C) according to claim 1, characterized in that the friction faces (631a, 632a) of the jaws (631, 632) extend parallel to said degree of freedom in translation, and in that said second operating means (60) guide the movement of each jaw (631, 632) along an arcuate trajectory in which said friction face (631a, 632a) moves parallel to itself, between said two distal and proximal positions.

3. Lifting system (1) for a package (C) according to claim 2, characterized in that the second operating means (60) comprise an actuator (601a) and, for each jaw (631, 632), a deformable parallelogram structure which comprises: - said jaw (631, 632), - a base (61), and - at least two connecting rods (602, 603, 604, 605) each assembled in free rotation with said base (61) and with said jaw (631, 632) around two separate pivot axes, which deformable parallelogram structure cooperates with said actuator (601a) for the operation of said jaw (631, 632) between its distal position and its proximal position.

4. Lifting system (1) for a package (C), according to claim 3, characterized in that at least two connecting rods (602, 603, 604, 605), belonging to two distinct deformable parallelogram structures, cooperate together by means of gears (602a, 603a, 604a, 605a), so as to ensure the synchronization of the associated jaws (631, 632).

5. Lifting system (1) for a package (C) according to any one of claims 3 or 4, characterized in that, in the proximal position, the angle between the plane passing through the pivot axes of each connecting rod and the normal to the friction face (631a, 632a) is between 5° and 9° if the coefficient of adhesion friction between each friction face (631a, 632a) and said sliding rod (531) is between 0.08 and 0.

16.

6. Lifting system (1) for a package (C) according to any one of claims 1 to 5, characterized in that, at each jaw (631, 632), said lifting system (1) has the following parameters: - a resultant angle, corresponding to an angle formed by the resultant of the forces applied between said jaw (631, 632) and said sliding rod (531), - an angle at the apex of an adhesion friction cone, corresponding to the maximum angle relative to a contact normal oriented perpendicular to said sliding rod (531) in which a force can be applied to the sliding rod (531) according to said degree of freedom in translation without generating a translation of said sliding rod (531), and in that said lifting system (1) is configured so that, when the jaws (631, 632) are in the active configuration, said resultant angle is less than said angle at the apex of the friction cone of adhesion.

7. Lifting system (1) for a package (C) according to any one of claims 1 to 6, characterized in that the controlled braking means (6) comprise mechanical stops (641, 642) to define an end-of-travel position for the jaws (631, 632) which is located beyond said proximal position and which is such that, in the end-of-travel position, all the components of the controlled braking means (6) are deformed elastically only.

8. Lifting system (1) for a package (C), according to any one of claims 1 to 7, characterized in that the sliding means (53) are configured so that said sliding rod (531), and its degree of freedom in translation, are oriented horizontally or vertically, and in that, when said degree of freedom in translation is oriented vertically, the controlled braking means (6) comprise means for compensating for the weight of the jaws (631, 632).

9. Lifting system (1) for a package (C), according to any one of claims 1 to 8, characterized in that the controlled braking means (6) comprise safety means which are configured to prevent control from the inactive configuration to the active configuration during a translation of the sliding rod (531) corresponding to a reduction in said distance dimension (D).

10. Lifting system (1) of a package (C) according to claim 9, characterized in that the safety means comprise a safety ring (65) which surrounds said sliding rod (531) so as to move between two positions: - an active position, during a translation of the sliding rod (531) corresponding to a reduction in said distance dimension (D), to cooperate with the jaws (631, 632) in the inactive configuration and prevent control of the inactive configuration towards the active configuration, and - an inactive position, during a translation of the sliding rod (531) corresponding to an increase in said distance dimension (D), to move away from the jaws (631, 632) in the inactive configuration and to allow control of said jaws (631, 632) from said inactive configuration towards said active configuration.

11. Lifting system (1) for a package (C), according to any one of claims 1 to 10, characterized in that it consists of: - a crane comprising a lifting point, the chassis of which comprises an upright and a boom, or - a gantry comprising at least two lifting points.

12. Method for lifting a package (C), between two reference frames (Ro, Rd) preferably having at least one relative vertical movement, for example for lifting the package (C) in the presence of a relative movement due to swell, by implementing a lifting system (1) according to any one of claims 1 to 11, which lifting method comprises: - for the passage from the proximal position to the distal position of the jaws (631, 632): - the control of the second operating means (60) to move the jaws (631, 632) from the proximal position to the distal position, Then, — if a force exerted on the sliding rod (531), coaxially with said degree of freedom in translation in a direction corresponding to a reduction in said distance dimension (D), is less than a predetermined threshold, execution of said command, otherwise — suspending said command until said effort decreases below said predetermined threshold, then executing said command, - for the transition from the distal position to the proximal position of the jaws (631,632): — controlling the second operating means (60) to move the jaws (631, 632) from the distal position to the proximal position, then, — if said distance dimension (D) increases, execution of said command, otherwise — suspension of said order until said distance rating (D) increases.

13. Lifting method according to claim 12, characterized in that it comprises the following operations: (i) during an operation of launching said package (C) from the reference frame (Ro) of the lifting system (1) towards a destination reference frame (Rd): - a step of suspending said package (C) from said lifting cable (3), in which the jaws (631, 632) are in the distal position and said mobile block of sheave(s) (52) is in an average position centered on an available stroke, - possibly, in combination with claim 10, a step of turning then drifting on a stroke allowing the safety ring (65) to be positioned in the inactive position, - a step of controlling the closing of the jaws (631, 632) towards the proximal position, - a turning step to lift the package (C) and place it above the destination reference (Rd), - a step of lowering said package (C) near the highest wave crests of the swell, - when the package (C) is placed on a wave crest or near a wave crest at the end of a rising front, a step of deflecting, preferably to come tangent to said wave crest, and of passing from the proximal position to the distal position of the jaws (631, 632), so that when said package (C) transfers its weight from said lifting cable (3) towards said destination reference (Rd), said lifting system (1) ensures passive compensation of the swell, and / or (ii) during an operation to recover said package (C) located on the destination reference frame (Rd), the jaws (631, 632) being in the distal position, said lifting system (1) ensuring passive compensation for the swell, - preferably when said package (C) is in an upward movement, a step of passing the jaws (631, 632) into the proximal position so that said mobile block of sheave(s) (52) continues its movement by increasing said distance dimension (D), this up to a wave crest where said mobile block of sheave(s) (52) is blocked in translation, - as soon as the jaws (631, 632) reach the proximal position, a turning step to lift the package (C) and place it above the reference frame (Ro) of the lifting system (1), - a step of lowering said package (C) onto the reference frame (Ro) of the lifting system (1).

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