Abstract:
A coupling assembly including an endpiece defining a fluid flow passageway and being adapted to be secured to an outlet of a fluid-flow circuit, and a coupling member including a body defining at least one housing for receiving locking balls, a slider defining an axial wall of the at least one housing, a control member surrounding the body and slider and being provided with a ball-locking element that is movable between a rest position in which it and the slider, in an advanced position thereof, retain the locking balls in an innermost locking position, and a release position wherein the slider is movable to allow the locking balls to move both linearly and outwardly to an unlocked position thereof, and return elements for returning the control member to its rest position.

Description:
BACKGROUND OF THE INVENTION 
     1.Field Of The Invention 
     The present invention relates to a coupling assembly for a fluid-flow circuit. 
     In the meaning of the invention, such a fluid flow circuit is particularly, but not exclusively, a hydraulic circuit for a motor vehicle, in particular a competition vehicle. The above-mentioned hydraulic circuit is constituted, for example, by a brake circuit or a cooling circuit. Nevertheless, the invention is applicable to types of fluid-flow circuit other than those mentioned above, and in particular to those forming part of machines for injecting plastics materials. 
     The coupling assembly in accordance with the invention allows these various types of fluid-flow circuit to be treated, in particular to be filled with fluid, cooling liquid or brake liquid, or else to be closed. The coupling assembly also makes it possible to verify at least one characteristic relating to the fluid, in particular its pressure. 
     2. Brief Description Of The Related Art 
     FR-A-2 707 603 discloses a safety plug suitable for co-operating with an endpiece for filling a tank with fluid under pressure. The plug comprises a body associated with a sliding ring for moving locking balls radially. 
     That known arrangement nevertheless implies certain drawbacks. The plug turns out to be relatively inconvenient to put into place, insofar as it requires the body to be pushed back while simultaneously pulling on the control ring. 
     FR-A-2 708 078 discloses a safety cutout for an installation for handling fluids under pressure. The cutout comprises two elements, one male and one female, that are secured to the ends of two portions of pipework, respectively connected to a source of pressure and to a tank of a vehicle, for example. Coupling and uncoupling are performed respectively by pushing and by pulling on the above-specified male and female elements. 
     That device also presents certain drawbacks. Given that it is a safety device intended to prevent the feed pipe being pulled away in untimely manner by the vehicle, it requires high levels of disconnection force, such that it does not lend itself easily to everyday handling. In this respect, it should be observed that if that device could be handled using small forces, that would lead to major risks of accidental disconnection. 
     OBJECT AND SUMMARY OF THE INVENTION 
     That said, the invention seeks to provide a coupling assembly comprising an endpiece and at least one complementary member suitable for being coupled to and uncoupled from said endpiece, in a manner that is simple and natural for an operator. 
     To this end, the invention provides a coupling assembly for a fluid-flow circuit, the assembly comprising an endpiece suitable for being secured to an outlet of said circuit, said endpiece being provided with means for receiving locking elements, in particular locking balls, said coupling assembly also comprising a coupling member suitable for co-operating with said endpiece, said coupling member comprising:
         a body;   at least one housing formed in the body for receiving said locking elements, which elements are movable between a locked position that is radially inner relative to a main axis of the body, and an unlocked position that is radially outer relative to said axis;   a slider defining an axial wall of said housing, said slider being movable between an advanced position in which it imparts a small axial size to said housing and in which the locking elements are blocked in their locking position by a locking element, and a retracted position in which the slider imparts a larger axial size to said housing;   a control member provided with said locking element and movable between an active position in which it entrains the slider into its advanced position, and a released position in which it comes into abutment against an end of the body that in use faces towards the endpiece; and   return means for returning the control member towards its released position, which return means are interposed between facing walls belonging respectively to the body and to the control member.       

     According to other characteristics of the invention:
         the return means of the control member are resilient return means, and comprise in particular at least one return spring;   it is further provided with return means for returning the slider into its advanced position;   the return means for the slider are interposed between facing walls of the slider and the control member;   the return means of the control member and the return means of the slider are in alignment with each other;   the return means of the control member and the return means of the slider are of resilient nature, the stiffness of the return means of the control member being considerably greater than the stiffness of the return means of the slider;   the control member is provided with a middle rib projecting radially inwards, the return means for said control member being interposed between said rib and a facing shoulder formed on the body of the coupling member, while the return means for the slider are interposed between said rib and the slider;   the endpiece has a movable valve member suitable for being moved by a stationary portion of the coupling member, while the coupling member possesses a movable valve member suitable for being moved by a stationary portion of the endpiece;   when the endpiece and the coupling member are separated, their respective stationary portions and their respective movable valve members together define respectively in the endpiece and in the coupling member complementary volumes having facing surfaces suitable for bearing flat one against another; and   said coupling assembly further comprises a plug suitable for co-operating with said endpiece instead of the coupling member, the plug comprising:
           a body having a closed end wall, that is remote in use from the endpiece;   at least one housing formed in the body, the housing serving to receive the locking elements that are movable between a locked position, radially towards the inside of the housing, and an unlocked position, radially towards the outside of the housing;   a slider defining an axial wall of the housing, said slider being movable between an advanced position in which it imparts a small axial size to the housing, and in which the locking elements are locked in their locked position by a locking element, and a retracted position in which it imparts a larger axial size to the housing;   a control member provided with the locking element, which control member is movable between an active position in which it entrains the slider into its advanced position, and a released position in which it comes into abutment against an end of the body that faces towards the endpiece in use; and   return means for returning the control member into its released position, which return means are interposed between the facing walls of the body and of the slider.   
               

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood and other advantages thereof appear more clearly in the light of the following description of an embodiment of a coupling assembly in accordance with the principle of the invention, given purely by way of non-limiting example and made with reference to the accompanying drawings, in which: 
         FIG. 1  is a side view showing the various component elements of a coupling assembly in accordance with the invention, shown in isolation from one another; 
         FIG. 2  shows the stage of coupling together an endpiece and a coupling member forming parts of the  FIG. 1  coupling assembly; 
         FIG. 3  is a side view showing the endpiece and the coupling member of  FIG. 2  in their coupled-together position; and 
         FIG. 4  is a side view, showing the stage of uncoupling the endpiece and the coupling member of  FIGS. 2 and 3 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The coupling assembly in accordance with the invention, shown in  FIG. 1 , comprises firstly an endpiece  2  for securing by any suitable means to the outlet (not shown) of a fluid-flow circuit. By way of non-limiting example, the circuit may be a hydraulic circuit in a motor vehicle, in particular a competition vehicle, or it may be a cooling circuit for an injection molding machine, or for electronics cards, in particular for a rail vehicle. 
     The endpiece  2  includes a cylindrical body  4 , having formed therein a peripheral groove  6 . It should be observed that the end wall, front face or free end  8 ′ of the body  4 , situated to the right in  FIG. 1 , i.e. at the coupling end of the endpiece, present an outer generator line that is rectilinear and parallel to the main axis of the endpiece. 
     The hollow body  4  defines a through housing or passageway  10  in which there is received a valve member  12 , housed against the walls of a neck  14  with a peripheral gasket  16  interposed therebetween. In conventional manner, the valve member  12  possesses end fingers  13  defining a fluid passage when in the open position, as described in greater detail below. Finally, a spring  18  is provided suitable for urging the valve member  12  against its seat, i.e. against the walls of the neck  14 . 
     References  8 ′ and  12 ′ designate the respective front faces of the body  4  and of the valve member  12 , i.e. faces that, in operation, face towards the complementary member that is to co-operate with the endpiece. In the arrangement of  FIG. 1 , these front faces  8 ′ and  12 ′ are generally coplanar, while being perpendicular to the main axis of the endpiece. 
     The coupling assembly in accordance with the invention, as shown in  FIG. 1 , also comprises a coupling member given overall reference  50 . This member  50  comprises a hollow body  52  that receives a likewise hollow bushing  54  on its end facing towards the endpiece  2 . The bushing  54  is pierced by a plurality of elongate slots  56  along which locking balls  58  are capable of sliding. The bushing  54  is provided with an end ring  60  facing towards the endpiece  2  and projecting radially outwards. 
     The coupling member  50  is provided with a central branch  62  extending on the main axis X′-X of said coupling member. At its end facing towards the endpiece  2 , the branch  62  is surrounded by a valve member  64  with an inside gasket  66  being interposed therebetween. An outside gasket  68  is also provided interposed between the valve member  64  and the inside periphery of the body  52 . 
     References  62 ′ and  64 ′ designate the respective front faces of the branch  62  and of the valve member  64 , i.e. their faces facing towards the endpiece  2 . In the arrangement of  FIG. 1 , these faces  62 ′ and  64 ′ are generally coplanar, extending perpendicularly to the main axis X′-X of the coupling member  50 . 
     In the closed position shown in  FIG. 1 , the valve member  64  is in abutment against the bushing  54 . A spring  70  is also provided having a first end pressing against the valve member  64  and having its other end resting against a shoulder  72  of the body  52 . As explained in greater detail below, the spring  70  is suitable for urging the valve member  64  into its closed position, i.e. into abutment against the bushing  54 . 
     A control sleeve  74  is slidably mounted on the outer periphery of the body  52 . At its end situated to the right in  FIG. 1 , i.e. its end remote from the endpiece  2 , the sleeve  74  possesses a drive collar  76  projecting radially outwards. Two shoulders, a shoulder  78  formed on the body  52 , and a shoulder  80  formed on the sleeve  74 , serve to limit the stroke of the sleeve  74  relative to the body  52 . The sleeve is also provided with a peripheral rib  82  projecting radially inwards and receiving the first end of a return spring  84 , having its other end bearing against an additional shoulder  86  formed at the periphery of the body  52 . 
     At its end remote from the collar  76 , the sleeve  74  possesses a frustoconical projection  88  extending radially inwards and suitable for co-operating with the balls  58 . More precisely, this projection  88  possesses a locking land  88   1  with two inclined lateral ramps  88   2  and  88   3  on either side thereof, facing respectively towards the endpiece  2  and away therefrom. 
     Finally, the coupling member  50  includes a slider  90  that is axially movable relative to the body  52 . This cylindrical slider possesses a margin  92  projecting radially inwards, and a shoulder  94  situated at the end of the slider  90  that is remote from the endpiece  2 . The shoulder  94  is suitable for coming into abutment against an additional shoulder  96  formed facing it on the control sleeve  74 . This shoulder  94  also receives the first end of a return spring  98  whose other end comes to bear against the rib  82  of the sleeve  74 . 
     It should be observed that the second spring  98  is not as strong as the first spring  84 , as can be seen more clearly from the description below of the coupling stage. It should also be emphasized that these two springs  84  and  98  extend in line with each other, which is advantageous in terms of overall radial size of the coupling member  50 . 
     Finally, it should be observed that the housing L for receiving the balls  58 , is defined by the facing walls belonging respectively to the margin  92  of the slider  90 , to the projection  88  of the sleeve  74 , and also to the ring  60  of the bushing  54 . As explained in greater detail below, the axial dimensions of this housing L can be varied. 
     The coupling assembly shown in  FIG. 1  also comprises a plug  100  suitable for co-operating with the endpiece  2  instead of the coupling member  50 . This plug  100  possesses a structure that is generally analogous to that of the coupling member  50 . As a result, the mechanical elements of this plug that correspond to mechanical elements of the coupling member are given the same reference numbers, plus  50 . 
     The plug  100  thus comprises a body  102  fitted with a bushing  104  having elongate slots  106  formed therein for receiving locking balls  108 . The body  102  is also provided with a peripheral ring  110  facing towards the endpiece  2 . 
     Unlike the coupling member  50 , the hollow body  102  of the plug  100  has a closed end wall  111  in the vicinity of which there is provided an O-ring  118 . The body  102  is surrounded by a control sleeve  124  fitted with a drive collar  126 . Unlike the sleeve  74 , the sleeve  124  fitted to the plug  100  also possesses a closed end wall  127 , extending in the vicinity of the end wall  111  belonging to the body  102 . 
     The ring  124  is provided with a projection  138  possessing a locking land  138   1 , and two lateral ramps  138   2  and  138   3 . A slider  140  is also provided that possesses a shoulder  144  suitable for co-operating with a complementary shoulder  146  formed on the sleeve  124 . The slider  140  is moved against a return spring  148  interposed between the slider  140  and an additional shoulder  136  formed on the body  102 . 
     There follows a description of how the above-described coupling is used, in particular a description of the co-operation between the endpiece  2  and the coupling member  50 . 
     In the uncoupled position, as shown in  FIG. 1 , the spring  18  urges the valve member  12  of the endpiece  2  into its closed position, i.e. bearing against the walls of the neck  14 . In addition, the spring  70  fitted to the coupling member  50  urges the valve member  64  into its closed position, bearing against the bushing  54 . The spring  84  urges the sleeve  74  towards the endpiece  2  such that the lateral ramp  88   2  of the projection  88  comes into abutment against the facing walls of the ring  60 . Furthermore the spring  98  urges the slider  90  against the sleeve  74 , such that the respective shoulders  94  and  96  are in abutment one against the other. 
     Under such conditions, the housing L possesses minimum axial dimensions. Consequently, the balls  58  possess substantially no room for moving axially, so they are held in place by the land  88   1  of the projection  88 . These balls  58  are thus in their radially retracted position. 
       FIG. 2  shows the stage of coupling the coupling member  50  relative to the endpiece  2 . For this purpose, the coupling member  50  is brought up to the endpiece  2  along arrow F 1 , i.e. towards the left in  FIG. 2 . This operation can be performed by pushing either against the sleeve  74  or against the body  52 . 
     Under such conditions, the free end  8 ′ of the body  4  of the endpiece  2  comes into contact with the locking balls  58  so as to cause them to move away from the ring  60 . The balls then cause the slider  90  to move against the spring  98 , but without moving the sleeve  74  or its projection  88 , in particular when the coupling member  50  is being pushed via the body  52 . As mentioned above, the spring  84  is stronger than the above-mentioned spring  98 . 
     The balls  58  thus run along the inside surface of the sleeve from the land  88 , towards the ramp  88   3  of the projection. Under such conditions, the balls then occupy a radially outer position, while the housing L takes on axial dimensions that are greater than those it presented when in the uncoupled position of  FIG. 1 . In this respect, it is emphasized that the balls  58  possesses two degrees of freedom relative to the body of the coupling member  50 , not only in a radial direction, but also in an axial direction. 
     It is then possible to cause the end walls  8  of the body  4  to slide along the balls  58 , since they are in their radial outer position. Then, the body  4  of the endpiece  2  comes into contact with the valve member  64  of the coupling member  50 , while the central branch  62  of said member  50  comes into contact with the valve member  12  of the endpiece  2 . This leads to relative displacement between the two valve members, i.e. the valve member  12  moves towards the left along arrow f 1 , while the valve member  64  moves to the right along arrow f 2 . 
     At the end of this movement, whereby the coupling member  50  moves closer to the endpiece  2 , and as shown in  FIG. 3 , the locking balls  58  are to the right of the peripheral groove  6 . The spring  98  which then encounters lower resistance, is suitable for driving the slider  90  axially, and consequently driving the balls  58 . The balls then roll along the ramp  88   3  of the projection  88  until they come against the land  88 , thereof, thus leading to the balls becoming locked in the groove  6 . 
     The coupling member  50  and the endpiece  2  are then in the coupled-together position, as shown in  FIG. 3 . It should be observed that in this arrangement, the housing L again possesses minimum axial dimensions, as in the uncoupled configuration of  FIG. 1 . Fluid can then flow along arrows f between the fingers  13  and also through the intermediate spaces left between the branch  62  and the valve members  12  and  64 . 
     If it is desired to uncouple the endpiece  2  from the coupling member  50 , then it is necessary to pull on the control sleeve  74  manually via its collar  76  against the spring  84  in the direction of arrows f 3  in  FIG. 4 . 
     This also causes the slider  90  to move axially, away from the ring  60 , because of the presence of the shoulders  94  and  96 . Consequently, the axial dimensions of the housing L are again increased, as in the coupling position shown in  FIG. 2 . 
     The projection  88  belonging to the sleeve  74  is also moved away from the ring  60  so that the balls  58  are no longer locked by the land  88   1 . The walls of the groove  6  then push the locking balls  58  radially outwards, so they roll over the land  88   1  of the projection and then over its other ramp  88   2 . In this respect, it should be observed that this movement takes place in the opposite direction to that which occurs during coupling, as described with reference to  FIG. 2 . The balls  58  then occupy their unlocked position of  FIG. 4 , i.e. a radially outer position. 
     By continuing to act on the control sleeve  74 , the operator then causes the coupling member  50  to slide manually relative to the endpiece  2  along arrow F 2  so that at the end of this movement the coupling member  50  and the endpiece  2  are uncoupled. It is then possible to release the traction being exerted on the sleeve  74  such that the sleeve returns to its rest position, as shown in  FIG. 1 , under drive from the return spring  84 . 
     It should be observed that both during coupling and during uncoupling, the plane faces  8 ′ and  12 ′, and also the plane faces  62 ′ and  64 ′, come to bear flat against each other in pairs. The same applies to the cylindrical portion  8  which engages with little clearance in the bore formed in the vicinity of the gasket  68 . This is particularly advantageous since any possibility of fluid becoming imprisoned is prevented during either of these operations. The plane and cylindrical surfaces which define substantially complementary volumes avoid creating any dead volume that would be suitable for generating drips or leaks during successive opening and closure operations performed on the coupling assembly in accordance with the invention. 
     The co-operation between the endpiece  2  and the plug  100  takes place in a manner that is generally analogous to that described above occurring between the endpiece  2  and the coupling member  50 . 
     Thus, if it is desired to couple the endpiece  2  with the plug  100 , the plug is moved up to the endpiece so that the free end  8 ′ of the endpiece  2  pushes the balls  108  back axially and consequently pushes the slider  140  against the spring  148 . Under such conditions, and as described above, the balls  108  are then in their unlocking position, corresponding to a radially extended configuration. 
     Thereafter it is possible to cause the plug to slide along the body  4  of the endpiece  2  until the O-ring  118  has been compressed and the endpiece comes close to the end wall  111  of the plug  100 . The balls  108  are then in register with the groove  6 , so that they penetrate therein under drive from the return spring  148  associated with the presence of the slider  140 . 
     If it is desired to uncouple the plug, then it is necessary to pull on the sleeve  124  away from the endpiece  2  so that the projection  138  no longer locks the balls  108  in place. The balls can then move out from the groove  6  so that it is again possible to cause the plug  100  to slide along the walls  8  of the endpiece  2  in order to be withdrawn completely. 
     The invention is not limited to the example described and shown. 
     Thus, in this example, mention is made of an endpiece and of a coupling member each possessing a respective moving valve member for closure purposes. Nevertheless, in a variant, it is possible for only one of those two mechanical members to be fitted with such a valve member. 
     It is also possible to envisage that neither the endpiece nor the coupling member has a valve member for closure purposes. Under such circumstances, once the coupling member is coupled to the endpiece, said coupling member is put into communication with a fluid feed source so as to admit fluid into the endpiece. 
     The invention serves to achieve the above-mentioned objects. 
     The coupling member or the plug is particularly convenient for a user to couple and uncouple relative to the endpiece. Thus, during coupling, it suffices to move the coupling member or the plug axially towards the endpiece in an entirely natural movement. Uncoupling is accompanied solely by applying traction on the control sleeve of the coupling member or the plug, i.e. by performing an action that is likewise natural. 
     The presence of the sleeve return means interposed between the facing walls of the body of the coupling member and said sleeve is also advantageous, in particular while coupling the coupling member on the endpiece. 
     In this respect, it should be emphasized that while the coupling assembly in accordance with the invention is in use, it can be advantageous for the operator to take hold of the coupling not via the sleeve  74  but via its body  52 . As a result, the coupling member is made more convenient to use for the operator, in particular insofar as the operator can place the coupling member in the most appropriate position relative to the disposition of the endpiece. 
     Under such conditions, the presence of these return means maintain the control ring in a determined position in spite of its weight which might cause it to move, so that the projection  88  fitted thereto is also in a well-defined position. In other words, the return means guarantee that whatever the orientation of the coupling member  50 , the locking balls  58  are maintained reliably in the groove  6  by the projection  88 . 
     In this respect, it should be observed that reliable locking is not necessarily ensured if the two springs  84  and  98  are replaced by a single spring extending between the shoulder  86  and the slider  90 . In such a configuration, when the endpiece  2  pushes back the balls  58  and the slider  90  during coupling, the sleeve  74  is no longer subjected to the action of said single spring. Under such conditions, it is capable of moving axially in unwanted manner, in particular when it is subjected to the action of gravity. It will be understood that such untimely movement can be harmful to the quality of the operations performed on said coupling member. 
     It is also emphasized that the coupling assembly in accordance with the invention is not the subject of untimely uncoupling, in particular when traction is applied to the body  52  of the coupling member  50 . This should be compared with the teaching of FR-A-2 708 078, in which such uncoupling can occur. 
     The coupling assembly in accordance with the invention is particularly adapted to installations that are difficult and relatively inaccessible, for example when cooling electronics cards or when the endpiece is to be found secured to the bottom of a well in which accessibility is reduced. It is possible to manipulate the coupling member or the plug even when the endpiece lies below the outlet from the well.