Abstract:
A coupler which is adapted to be connected to a complementary device for the transfer of a fluid between the coupler to the complementary device comprises a body through which the fluid is allowed to flow, at least one seal for providing a fluid-tight seal between the coupler and the complementary device, and a protecting device for the seal. The protecting device is movable between a first position before connection in which the protecting device projects beyond the seal in the direction of connection, and a second position after connection in which the protecting device no longer projects beyond the seal. The coupler also includes a damper for urging the protecting device towards its first position.

Description:
This application is a continuation of U.S. patent application Ser. No. 10/499,463 filed on Jun. 18, 2004, which is based on PCT Patent Application No. PCT/EP2002/014869 filed on Dec. 19, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates in a general way to couplers. 
     As is well known, a coupler is a mechanical assembly comprising clamping modules, intended in particular for applying a pre-clamping force so as to provide mechanical linkage and fluid-tightness between an articulated product loading and unloading arms, in particular for fluid products, for example petroleum products (liquefied natural gas etc.), and a complementary means installed on a ship. 
     The present invention relates more particularly to the case when the coupler is a hydraulic coupler with several clamping modules, in practice three or more, capable of conveying liquid products at very low temperatures (down to −196° C.). 
     According to a known arrangement, each clamping module comprises a clamping jaw designed for connecting the coupler to a complementary means, such as a manifold, and an actuating system proper to the said jaw and comprising a device of the screw/nut type driven by a motor. The jaw is carried by a system of rods articulated at one of its ends, on a support, the actuating system acting upon the system of rods in order to impel the jaw towards a clamping position or to bring it back to a resting position. 
     However, in devices of this type that are already known, the forces transmitted by the rods depend on the thickness of the manifold flange at the clamping location which, in practice, varies from one location to another on the flange. 
     As a result the clamping is often insufficient or excessive. 
     SUMMARY OF THE INVENTION 
     The present invention relates, in a general way, to an arrangement that makes it possible to provide, more simply and more reliably, clamping effected by means of the said clamping modules and leading in addition to other advantages. 
     More precisely, it relates to a clamping assembly for a coupler, comprising at least one clamping module having a clamping jaw designed for connecting the coupler to a complementary means, and an actuating system proper to the said jaw and comprising a device of the screw/nut type driven by a motor, characterized in that the actuating system is connected directly to the jaw and the said jaw is mounted on a support in such a way that it can swivel about a fixed point defined by the said support, the latter being intended to be fixed to the coupler. 
     In other words, the actuating system acts directly upon the clamping jaw. Having eliminated an intermediary (the rods), it becomes possible to obtain much greater clamping forces than previously, with a system that is simpler and more reliable than the known systems. Moreover, with the clamping assembly according to the invention, the coupler can be used in more situations. 
     According to preferred characteristics relating to this arrangement:
         the device of the screw/nut type is articulated on the jaw at a second point located a fixed distance from the said fixed point; and/or   the device of the screw/nut type comprises a screw that engages in a bush with an internal thread and is driven by the motor by means of a chain; and/or   the coupler is a hydraulic coupler and the motor is a hydraulic motor; and/or   the actuating system is carried by the support.       

     Furthermore, the arrangement according to the invention lends itself advantageously to a development that is original per se, according to which the assembly comprises several clamping modules whose motors have a fluid connection to a hydraulic unit comprising a fluid distribution circuit and control means designed for controlling the supply of fluid to the motors by the hydraulic unit, so as to cause the jaws associated with the motors to swivel, according to a serial arrangement of the motors so long as the jaws do not exert any clamping force on the complementary means and according to a parallel arrangement of the motors when the said jaws exert a clamping force. 
     This development gives a high speed of maneuver (serial arrangement of the motors), as well as a large clamping force at the appropriate time (parallel arrangement of the motors). 
     According to preferred characteristics relating to this development:
         the controlling means are, in addition, able to control supply to the motors according to a parallel arrangement so as to overcome the clamping force applied by the jaws to the complementary means, during unclamping of the jaws; and/or   the controlling means are sensitive to the increase in pressure in the hydraulic unit, resulting from the clamping force applied by the jaws to the complementary means, and are able to generate the transition from a serial arrangement of the motors to a parallel arrangement of them when the pressure reaches a predetermined value; and/or   the controlling means comprise a slide valve provided with a return spring and a pressure limiter with a return spring, installed upstream of the slide valve in the fluid distribution circuit and with fluid connection to the said slide valve; and/or   the hydraulic unit comprises a selector installed in the circuit so as to provide fluid connection between the inlet of the first of the motors in the direction of feed of the latter and the pressure limiter, the fluid distribution circuit supplying the motors according to two opposite directions depending on whether it is operating in clamping or unclamping; and/or   the fluid distribution circuit comprises a main unit for supply of oil constituting the said fluid.       

     The arrangement according to the invention also lends itself to another development that is original per se, and can be combined advantageously with the preceding one, and according to which the coupler comprises sealing means that are intended to ensure fluid-tightness of the connection of the coupler to the complementary means, means for protecting the sealing means, movable between a first position before connection, in which the said protecting means go beyond the sealing means in the direction of connection, and a second position after connection, in which the said protecting means are no longer projecting relative to the sealing means, and damping means that permanently exert a force on the protecting means impelling them towards their first position. 
     With this development there is maximum limitation of the risks connected with relative movements and impacts at the time of connection. 
     According to preferred characteristics relating to this development:
         the coupler comprises means that hold back the protecting means, preventing the said protecting means from going beyond the first position in the direction of connection; and/or   the sealing means comprise at least one ring seal and the protecting means comprise a movable ring that surrounds the seal or seals; and/or   the sealing means comprise at least one ring seal and the protecting means comprise several thrusters encircling the seal or seals; and/or   the damping means consist of a single spring washer, helical springs, spring washers, gas spring jacks or hydraulic dampers interposed between the protecting means and the body of the coupler.       

     The invention also relates to a hydraulic coupler, comprising a clamping assembly as defined above and fixed to the body of the said coupler. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The characteristics and advantages of the invention will become clearer from the description that is to follow, by way of an example, referring to the appended schematic drawings, where: 
         FIG. 1  is a side view with partial section of a hydraulic coupler equipped with a clamping assembly according to the invention and a complementary means, in the non-connected position; 
         FIG. 2  is a view similar to  FIG. 1 , and shows the connected position of the hydraulic coupler and of the complementary means; 
         FIG. 3 , on a larger scale, is a top view with partial section of the clamping module in  FIG. 2 ; 
         FIG. 4  is a view in longitudinal section of the top half of the front part of the coupler in  FIGS. 1 and 2  and illustrates the protecting means of the sealing means of the said coupler; and 
         FIGS. 5 to 10  are schematic diagrams of the hydraulic unit supplying the motors of the clamping modules according to the invention, and illustrate the various stages in operation of this unit. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the embodiment shown, the hydraulic coupler  10  according to the invention comprises a clamping module  11  having a clamping jaw  12  designed for connecting the coupler  10  to a complementary means  13 , and an actuating system  14  proper to the said jaw and comprising a device of the screw/nut type  15  driven by a motor  16 . 
     In practice, the clamping modules are three in number, fixed to the periphery of hydraulic coupler  10  and distributed uniformly around the latter and constituting a clamping assembly by which coupler  10  can be connected to the complementary means  13 . The said complementary means  13  is, here, a manifold, which can be replaced with a closing cover when the loading arm equipped with coupler  10  is to be put in the storage position. 
     As the actuating system  14  is well-known, it will not be described in detail here. 
     It will simply be pointed out that in the embodiment illustrated (see  FIG. 3 ), the device of the screw/nut type  15  comprises a screw  17  that engages in a bush with an internal thread  18  and is driven by the motor  16  by means of a chain  19  transmitting the rotary motion of motor  16  to screw  17  by means of a driving sprocket  20  rigidly locked with the output shaft of motor  16  and a driven sprocket  21  integral with a piece of shaft  22  that is an extension of screw  17 . The latter is housed in a cylindrical casing  23 , to which a housing  24  is fixed, for housing the chain  19  and sprockets  20  and  21 , the motor  16  being fixed to the said housing  24 . 
     Furthermore, the bush with internal thread  18  is slidably guided in the cylindrical casing  23 . 
     According to the invention, each jaw  12  has a swivel mounting on a support  25  about a fixed point  26  defined by the said support  25 , the latter being fixed to the hydraulic coupler  10 , in the present case by welding. 
     The device of the screw/nut type  15  is also articulated on jaw  12  at a second point  27  located a fixed distance from point  26  by means of a cylindrical component  28  which is fixed to one end of the bush  18  and is configured to receive a spindle (not shown in  FIG. 3 ). 
     The actuating system  14  in its turn is swivel mounted on support  25  by means of spindle-receiving disks  29  fixed on the cylindrical casing  23 . 
     It should also be pointed out that support  25  is formed by two plates  30  that which are symmetrical relative to a longitudinal median plane intersecting at right angles the swiveling axes of clamping module  11  and which receive between them the actuating system  14  as well as the jaw  12 , which is, in turn, formed by two plates  31  that are symmetrical relative to the said plane. 
     More precisely, each plate  30  of support  25  comprises a vertical section  32  (see  FIGS. 1 and 2 ), on which the actuating system  14  is swivel-mounted, and a horizontal section  33  defining the fixed point  26 . 
     Each horizontal section  33  is reinforced, in the region of the fixed point  26 , by an outer plate  34  welded onto the adjacent plate  30 . 
     Each plate  31  of jaw  12  comprises, according to a general configuration of a right-angled triangle, two holes through which spindles pass, one for the spindle housed in cylindrical component  28  and defining the swivel point  27  and the other for the journal  35  defining the fixed swivel point  26 . Holes aligned with the aforementioned holes are of course also provided in the support plates  25 . 
     A clamp  36  carrying a sliding block  37  is fixed to jaw  12 . It, too, is formed from two plates  38  that are symmetrical relative to the aforesaid plane, each being fixed to one of the plates  31  forming jaw  12 . 
     It should be pointed out, in this connection, that these plates  38  extend along the side of the substantially triangular plates  31  closest to the hydraulic coupler  10  and they also have a hole through which journal  35  passes. Furthermore, it should also be noted that the sliding block makes it possible to connect the hydraulic coupler  10  to several different diameters of flanges  39  of manifold  13 . In practice, and such is the case in the embodiment shown here, these diameters are generally three in number. 
     Thus, the jaw  12  is pivotably mounted on the support  25  about a low fixed point  26  (proximal point with respect to the coupler  10 ) defined by the support  25 , the device of screw/nut type  15  is articulated directly on the jaw  12  at a high point  27  (distal point with respect to the coupler  10 ) defined by the jaw  12  and situated at a fixed distance from the low fixed point  26  and the actuating system  14  is itself articulated on the support  25  in the vicinity of the high point  27 . 
     It will also be noted that the clamp  36  of the jaw  12  forms a projection roughly with respect to a third point defined by the jaw  12  and forming a triangle with the low and high points. 
     Furthermore, the extension of each jaw  12  and of the device  15  of screw/nut type which is associated with it is in the same general direction as that of the body, here cylindrical, of the coupler  10 . 
     Moreover, hydraulic coupler  10  is equipped with a system that protects its seals, as can best be seen in  FIG. 4 . 
     In the embodiment shown, the hydraulic coupler  10  comprises a protecting ring  40  that is movable relative to the annular front face  41  of coupler  10  and is positioned around ring seals  42  and  43  housed in corresponding grooves in the body  45  of coupler  10 . Compression springs, only one of which is visible in  FIG. 4 , bearing the reference sign  44 , are placed between this ring  40  and the body  45  of coupler  10  and act in the axial direction, permanently holding the ring  40  and the body  45  of coupler  10  apart. 
     In practice, the ring has a groove  46  forming a seat for one of the ends of these springs  44 , whereas the body  45  of coupler  10  has an opposite face  47  that is recessed relative to the front face  41  and forms a seat for the opposite end of the said springs  44 . 
     When coupler  10  is in the closed position (see  FIG. 2 ) on a flange  39  of manifold  13 , the springs  44  are compressed and flange  39  is in contact with seals  42  and  43  and a front face  48  of ring  40  located on the side of the latter opposite to that with the groove  46 . 
     When coupler  10  is in the open position (see  FIG. 1 ), ring  40  abuts against the centering guides  49  of coupler  10 , just one of which is visible in  FIG. 4 . In this position, the springs  44  are pre-compressed and not completely released. 
     When coupler  10  is brought closer to flange  39 , the seals  42  and  43  are recessed relative to the face  48  of ring  40  and so are protected from any impacts due to flange  39  to be connected. The energy of these impacts is absorbed by the work of compression of springs  44 . 
     Then, during closing of the jaws  12  of coupler  10 , springs  44  are compressed by the clamping force exerted by the clamping modules  11 . It will be appreciated, in this connection, that the reactive force of ring  40  on flange  39 , created by springs  44 , makes it possible to eliminate any relative radial movements that could, without this protecting system, cause deterioration of seals  42  and  43  by friction. 
     In the closed position, the supporting force of seals  42  and  43  is equal to the clamping force of jaws  12  minus the force of compression of springs  44 . In practice, therefore, the clamping force of jaws  12  must be chosen in such a way that it is much greater than the force of compression of springs  44 . 
     Moreover, various types of damping springs can be used:
         a single spring washer with the same diameter as the groove of ring  40 ,   one or a number of helical springs,   one or a number of spring washers,   gas spring jacks or hydraulic dampers.       

     According to a variant of this protecting system, ring  40  can be replaced with thrusters positioned around seals  42  and  43  and connected to the damping means defined above. 
     Other solutions for abutment can also be used, such as pins fixed to the body  45  and equipped with a head retaining ring  40 . 
     For supplying oil to the hydraulic motors  16  of the clamping modules  11 , a hydraulic unit with a fluid distribution circuit is also provided, as is best seen in  FIGS. 5 to 10 . 
     The said hydraulic unit  50  comprises, according to the invention, a slide valve  51  provided with a return spring and a pressure limiter  52  with a return spring, installed upstream of valve  51  in the distribution circuit and with fluid connection to the said valve  51 . 
     The hydraulic unit  50  also has a selector  54  arranged in the fluid distribution circuit to provide fluid connection between the inlet of the first of the motors  16   1 - 16   3 , in their direction of supply, and pressure limiter  52 . Depending on whether the unit is acting for clamping or unclamping of jaws  12 , the first motor is motor  16   1  or  16   3 . 
     The said hydraulic unit  50  is in addition supplied with oil by a central unit  55  comprising a distributor  56  and two non-return valves with controllable throttling  57 , connected respectively to a closing line and an opening line connecting the central unit  55  to hydraulic unit  50 . 
     As can be seen in  FIGS. 5 to 10 , the fluid distribution circuit of hydraulic unit  50  is designed for supplying all the motors  16   1 - 16   3  with the oil flow and pressure that they require, and at any time. According to the invention, for this purpose the hydraulic unit  50  operates according to the series/parallel principle. 
     More precisely, during the stages of approach for closing, the clamping modules  11  with jaws  12   1 - 12   3  maneuver rapidly. For this, the hydraulic unit operates in series (low pressure and high flow rate). For clamping onto a flange  39 , the unit operates in parallel (high pressure and low flow rate). 
     When coupler  10  is clamped on a flange  39 , for unclamping it the hydraulic unit  50  has to supply a lot of pressure to each of the motors  16   1 - 16   3 : therefore it operates in parallel. As soon as all of the clamping modules  11  are unclamped, hydraulic unit  50  changes to series operation to give quick opening. 
     Series/parallel changeover of hydraulic unit  50  occurs in relation to the forces transmitted and to be transmitted to the clamping modules  11 . It is the slide valve inside hydraulic unit  50  that permits changeover either to series operation or to parallel operation. The position of this slide valve depends on the forces transmitted by the clamping modules  11 . When there is no force acting on the clamping modules  11 , hydraulic unit  50  puts itself in the series position. As soon as a clamping module  11  forces or presses against something (flange, stop etc.), the supply pressure of the series circuit increases and moves the slide valve towards its position for supplying motors  16   1 - 16   3  in parallel, so as to deliver the maximum available pressure to each of these motors. Modules  11  then have a low speed but a high transmissible force. Conversely, when there is no longer any force on anyone of the clamping modules  11 , the internal pressure of hydraulic unit  50  decreases and thus allows the slide valve to move to its series position. 
     The operation of hydraulic unit  50  will now be described in greater detail, referring to  FIGS. 5 to 10 . 
       FIG. 5 : (Coupler  10  in the Open Position) 
     No movement is “demanded” from coupler  10 . There is no circulation of oil in the hydraulic circuit. In this state (rest), the hydraulic unit is systematically in the series position. The slide valve of unit  50  is pushed towards the left by its return spring. 
       FIG. 6 : (Coupler  10  in Course of Closing) 
     During this approach phase, no force of resistance is received by the clamping modules  11 . Hydraulic unit  50  therefore operates in series, so that there is rapid movement of modules  11 . The oil leaving motor  16   1  goes into motor  16   2  after briefly passing through hydraulic unit  50 , then leaves it again and enters the unit and then motor  16   3 , before returning to the central unit  55 . 
       FIG. 7 : (Coupler  10  in the Clamping Phase) 
     During the clamping phase, a resistance appears at the jaws  12   1 - 12   3 , giving rise to an increase in the hydraulic pressure of the circuit. The pressure will therefore push the valve slide in hydraulic unit  50  towards the right in the diagrams. At that moment, unit  50  will therefore change over to the parallel position, which means that each motor  16   1 - 16   3  will be supplied directly by the central unit  55  and not by the preceding motor. The flow will therefore be divided as a function of the number of motors. On the other hand the pressure will increase. At the outlet of each motor  16   1 - 16   3 , the oil returns directly to the central unit  55 . 
       FIG. 8 : (Coupler  10  Closed) 
     Once coupler  10  is closed, oil circulation stops. The slide valve in unit  50  therefore goes back to the series position (displaced towards the left in the diagrams), under the action of its return spring. 
       FIG. 9 : (Unclamping of Coupler  10 ) 
     At the moment of opening, it is necessary to overcome the forces due to clamping. These forces have the effect of raising the pressure within the hydraulic circuit, and therefore of causing unit  50  to change to the parallel position (the pressure displaces the valve slide of unit  50  towards the right in the diagrams). Each jaw  12   1 - 12   3  therefore has a high oil pressure at its disposal, which enables them to be unclamped. 
       FIG. 10 : (Opening of Coupler  10 ) 
     Once coupler  10  is unclamped, there is no longer any force to be overcome. The internal pressure of the hydraulic circuit decreases, causing the valve slide in unit  50  to move towards the left in the diagrams. During this opening phase, unit  50  is in the series position, permitting rapid movement of jaws  12   1 - 12   3 . 
     In practice, it may be noted, as a non-limiting example, that for a maximum outlet pressure of central unit  55  of about 150×10 5  Pa, the pressure value causing the slide to move from a position in series to a position in parallel is about 80-90×10 5  Pa. 
     In the embodiment shown in  FIGS. 5 to 9 , movement of the slide from a series position to a parallel position depends on whether the pressure limiter is in the open or closed position, these positions depending in their turn on the return spring chosen for the said limiter  52 . 
     However, in other embodiments it would be possible for the slide valve  51  to be designed so that it changes from one position to the other by an appropriate choice of return spring for it. In this case it will not be necessary to employ a pressure limiter  52 . 
     It would also be possible, in another embodiment, to employ detectors of the position of the jaws or of the pressure at motors  16   1 - 16   3  and electric control of slide valve  51 . 
     The actuating system  14  may also be borne by a support different to that on which is mounted the jaw  12  associated with it. 
     The support or supports may, moreover, also be formed integrally with the coupler. 
     Of course, the present invention is not limited to the embodiment that has been described and illustrated, but encompasses all variants of execution.