Abstract:
A connection device including a tubular male termination, a connecting means adapted to be mounted around and accommodated in a groove of the female termination, and a locking member for locking these means in the female termination to be mounted around the male termination to reversibly move these means into a locking position in the groove. The device includes means for immobilizing and releasing the locking member that are rigidly fastened to the male termination, these means being adapted to prevent the connecting means from being moved to the locking position unless the male termination occupies a predetermined insertion position in the female termination and, only if the male termination has reached that position, to release the locking member, while allowing its movement toward the female termination so that a thrust on this member moves the connecting means into the locking position.

Description:
FIELD OF THE INVENTION 
     The present invention concerns a connection device for a fluid transfer line, a fuel injector return circuit incorporating it, and a method for mounting/demounting this device in/from a tubular female termination to be connected to a male termination that the device comprises. The invention applies generally to all connections between such fluid transfer terminations, in particular low pressure terminations, and notably to fuel injection manifold for motor vehicles. 
     BACKGROUND 
     Generally speaking, it is known for fuel injection manifolds to use connection devices with a tubular male termination that fits in sealed manner inside a tubular female termination or “canula” by means of a flexible connecting member that is mounted on and fastened to the male termination and that may be locked at its axially interior end into a circumferential internal groove of the female termination under the control of a locking member cooperating with an axially exterior part of that connecting member. 
     There may be cited for example the document WO A 2007/042344 which describes a device of this kind in which the connecting member includes two diametrically opposite axial arms that are formed in one piece with the male termination and that are locked elastically into the groove of the female termination by bending them in the radial direction, opposing them being pulled out axially. 
     A major drawback of such a known connection device is that as soon as the male termination is locked into the female termination but the connecting member is not positioned in the connecting groove of the female termination it is no longer possible thereafter to move the connecting member into that groove. 
     The document EP A 2 236 894 in the name of the Applicant describes a connection device of another type including a locking member to be mounted around a male termination and the axially interior end of which is adapted to be connected to the groove of the female termination and is formed by connecting lugs that are elastically deformable when bent radially. Each of these lugs is adapted to be immobilized in a locking position against the groove, following a thrust applied to the locking member, via bending of the lugs in contact with guide and locking assistance ramps associated with those lugs that project radially on the male termination. 
     The connection device described in the latter document is entirely satisfactory because it meets the sealing and mechanical strength requirements specific to fuel injection manifolds in particular. These ramps and these associated lugs notably provide a “self-locking” function with the device in the locking position, thanks to the radial compression force exerted by the ramps on the lugs, pressing them into the groove, which force increases in proportion to the pressure of the fluid circulating in the male termination. This results in more secure functioning of the device even at high pressures. 
     SUMMARY 
     The Applicant has nevertheless sought to improve this device by adding an additional safety or double locking feature. A drawback of the above device is that its locking member may be lowered axially inward around the male termination in such a manner that its lugs are bent by the ramps of the male termination even if the latter is outside the female termination and that an operator does not know precisely when to lower this member around the male termination to immobilize the lugs in the groove of the female termination. 
     An object of the present invention is thus to propose a connection device for a fluid transfer line, in particular a low-pressure line, comprising:
         a tubular male termination,   a connecting means configured to be mounted around the male termination while being connected to a tubular female termination by a radially internal face thereof, this means being configured to be accommodated in a connecting groove of this internal face, and   a locking member for locking the connecting means in the female termination, this member being adapted to be mounted around the male termination to reversibly move these means into a locking position in said groove.       

     To this end a device of the invention comprises means for immobilizing and releasing the locking member that are rigidly fastened to the male termination and are elastically deformable by bending in contact with an entry end of said internal face of the female termination, these immobilizing and release means being configured to prevent said connecting means from being moved to said locking position unless the male termination occupies a predetermined insertion position in the female termination and, only if the male termination has reached said insertion position, to release the locking member while allowing its movement toward the female termination so that a thrust on this member moves said connecting means into said locking position. 
     In the present description, the expressions “axially interior” or “axially inward” mean a location in the connected state relative to the axis of symmetry of the male and female terminations that is directed toward the interior of the connector, i.e. in a manner proximal to the connecting groove of the female termination; conversely, the expressions “axially exterior” or “axially outward” mean a location relative to that axis on the opposite (i.e. distal) side of that groove. 
     According to another feature of the invention, said immobilizing and release means may be retractable by elastic bending in the manner of lever arms in contact with said entry end of the female termination, these means being configured to occupy an immobilizing position in which the locking member abuts axially on these means which are deployed radially outward, and a release position in which this member is able to slide freely toward the female termination around these means that are retracted radially inward. 
     Said immobilizing and release means advantageously comprise a pair of arms formed in one piece with the male termination that extend symmetrically to each other with respect to the axis of the main termination from an axially internal area thereof, these arms, in said immobilizing position, being deployed on either side of this area at a same acute angle and, in said release position, being bent parallel to the axis of the male termination. 
     According to another feature of the invention, the locking member may include two internal rims or shoulders that are configured to abut on two free ends of said arms, respectively, deployed in their immobilizing position, and to lie radially outside the arms in said release position, these rims or shoulders being formed axially toward the exterior of an axially interior connecting end of said connecting means and being configured to lie axially outside the female termination in said locking position. 
     According to a further feature of the invention, each of said arms, of oblong blade shape, for example, has an external face relative to the male termination on which may be formed at least one projecting protuberance configured to cooperate with said entry end of the female termination when the male termination occupies said insertion position, said at least one protuberance preferably being formed substantially at the mid-height of the corresponding arm. 
     In an advantageous embodiment of the invention each of said arms has at least two of said protuberances in the form of parallel transverse ribs that are configured to cause these arms to close to obtain its release position and furthermore to emit, by rubbing in contact with said entry end of the female termination, a noise informing an operator that said insertion position of the male termination has been reached and therefore that said connecting means can be locked in said groove. 
     It will be noted that these arms forming said means for immobilizing and releasing the locking member may also serve to guide the male termination in circumferential translation in the female termination to facilitate centering of the connecting lugs at the entry to said groove. 
     According to a further feature of the invention, said connecting means may be formed in one piece with the locking member of which it forms an axially interior part, and this connecting means may include an axially interior connecting end comprising for example at least two connecting lugs elastically deformable in the radial direction extending axially inward and radially outward, the radially external and internal faces of each lug being able to be immobilized in said locking position by bending of each lug, respectively against said groove and against one of the corresponding guide and locking aid ramps of the male termination that are respectively associated with said lugs, said immobilizing and release means being configured to cooperate with the locking member independently of said ramps and lugs. 
     It will be noted that these connecting lugs and the associated guiding/immobilizing ramps may be as described in the aforementioned document EP A 2 236 894 in the name of the Applicant, for example. These lugs formed in one piece with the locking member have the advantage of low cost and easy assembly of the device compared to other known two-part devices and further contribute to imparting to the device improved mechanical strength against pulling out, as explained above. 
     According to a further feature of this embodiment of the invention using connecting lugs guided and immobilized in the groove of the female termination by ramps of the male termination, said arms are formed angularly between said ramps of which there are two and which are diametrically opposed for example, said at least one protuberance of each arm being formed axially outside each of the ramps. 
     According to a further feature of this embodiment of the invention using said lugs and ramps the locking member has said internal rims or shoulders that are formed angularly between these lugs and axially outside them, and said lugs, of which there are two for example, may each be of circular arc shape and the lugs being interconnected by as many notches configured to render these lugs sufficiently deformable in radial bending. 
     The locking member advantageously comprises holding means forming an axially exterior end of this member and that may have at least one radial plate configured to be pushed manually by an operator toward the female termination, and this member may cooperate with the male termination to give a visual indication that said locking position for said connecting means has been reached. 
     These holding means may for example be constituted of a single radial thrust plate that is removably mounted on an axially exterior and preferably discontinuous edge of the locking member and which, in said locking position, cooperates with an axial locking indicator pin extending between two bearing surfaces of the male termination so that this pin of the male termination is flush with the external face of said plate, which face is then axially level with and between these two bearing surfaces. 
     Alternatively, these means for holding the locking member may comprise two radial thrust plates that lie on respective opposite sides of a single bearing surface of the male termination, as in the member described in the aforementioned document EP A 2 236 894. 
     A fuel injector return circuit of the invention includes a tubular male termination connected to a tubular female termination by a connection device as defined hereinabove. 
     A method of mounting in a locking position and of demounting a connection device as defined above in a tubular female termination to be connected to a male termination of the device comprises the following successive mounting steps: 
     a) the connecting means and the locking member are positioned around the male termination in such a manner that the locking member abuts axially on said immobilizing and release means, which prevents axially inward movement of the connecting means, 
     b) the male termination is inserted into the female termination to connect it thereto in said predetermined insertion position, which elastically bends these immobilizing and release means in contact with said entry end of the female termination so that the locking member no longer abuts on these means, which then allows axially inward movement of the connecting means, then 
     c) an axially inward thrust is exerted on the locking member to move the connecting means into said locking position inside said groove of the female termination, 
     and, for demounting the device, axially outward traction is exerted on the locking member whilst holding the male termination against the bottom of the female termination so as to extract the connecting means therefrom, after which the male termination is extracted from the female termination. 
     According to a further feature of the invention, in the step a) two internal rims or shoulders of the locking member, which are formed axially toward the exterior of said connecting means, are caused to abut against respective free ends of two retractable arms that form said immobilizing and release means, and then, in the step b), these arms may be retracted by bending them radially inward of said corresponding internal rims or shoulders to the contact of said entry end of the female termination, by rubbing at least one external protuberance situated substantially at mid-height of each arm against a chamfer of this entry end. 
     According to a further feature of the invention, in said locking position obtained after the step c), said internal rims or shoulders of the locking member are axially outside the female termination, and two diametrically opposite elastically deformable connecting lugs that form said connecting means may be immobilized by bending against said groove and against two corresponding guide and locking aid ramps of the male termination that are respectively associated with said lugs, which are angularly situated on either side of said arms. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features, advantages and details of the present invention will emerge on reading the following description of one embodiment of the invention given by way of nonlimiting illustration, this description being given with reference to the appended drawings, in which: 
         FIG. 1  is an exploded perspective view of a connection device of the invention intended to be mounted in a female termination (partially represented), 
         FIG. 2  is an exploded view in elevation of the device and the female termination from  FIG. 1 , 
         FIG. 3  is an exploded view in axial section of this device and this female termination taken along the line in  FIG. 1 , 
         FIG. 4  is a detail view in axial section of the  FIG. 3  device when assembled without the female termination receiving it in a position immobilizing the arms of the male termination on which the locking member abuts, 
         FIG. 5  is a view in axial section of the  FIG. 4  device with the male termination partially inserted into the female termination from  FIG. 3  and with its arms in this immobilizing position, 
         FIG. 6  is a view in axial section of the  FIG. 5  device with the male termination completely inserted in the female termination and with its arms in a position releasing the locking member, 
         FIG. 7  is a view in axial section of the  FIG. 6  device with the male termination completely inserted in the female termination, in a locking position of the locking member obtained following sliding thereof toward the female termination, 
         FIG. 8  is a view of the  FIG. 7  device in axial section taken along the line VIII-VIII in  FIG. 1 , showing the connecting end of the locking member in the locking position, and 
         FIG. 9  is a view in axial section of the same device in this locking position, with the left-hand half of the locking device shown in the section plane of  FIG. 8  and its right-hand half shown in the orthogonal section plane of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     The tubular male termination  1  shown in  FIG. 1  has, in known manner, at its axially exterior (i.e. upper) end, two branch connectors  2  and  3  in the form of spigots that extend symmetrically on either side of two bearing surfaces  4   a ,  4   b  for the operator provided on this termination  1  and, at its axially interior (i.e. lower) end, a circumferential groove  5  intended to receive an O-ring seal  6  mounted in or molded into this groove  5 . Moreover, two ramps  7   a ,  7   b  are formed so as to project radially from a lower portion of the male termination  1  situated above the groove  5  in order to exert a guiding and locking aid function, as explained hereinafter. 
     The tubular female termination  10  (seen in particular in  FIG. 3 ), of canula type and standard shape, essentially has on its radially internal face  11 , in the immediate vicinity of its axially external (i.e. upper) entry end  12 , a circumferential connecting groove  13  that is of substantially trapezoidal axial section and is intended to receive axially an interior connecting means  20  formed at a lower end of the device. The female termination  10  also has, in the immediate vicinity of its axially interior end, a circumferential sealing area  14  intended to receive the seal  6 . In known manner, the internal section of the female termination  10  has a constriction  15  axially below the groove  13 . 
     To be more precise, the connection end is formed by two lugs  21   a ,  21   b  of circular arc shape elastically deformable in radial bending (of which there are two in this embodiment, of lobe shape), that are included in a locking member  30  of the device, forming its lower end. This member  30  is produced in a plastic material of high mechanical strength, for example a polyamide, and in this embodiment essentially includes:
         holding means  31  forming an upper end of the member  30  and constituted of a radial plate that is intended to be pushed manually by the operator toward the female termination  10  and that is removably mounted on two upper edge portions  32   a ,  32   b  of circular arc shape of a main body  33  of the member  30  via two corresponding openings  31   a ,  31   b  in the plate  31  receiving them, and   the globally cylindrical main body  33 , with its edge portions  32   a ,  32   b  that are extended downward by diametrically opposite cylindrical arcs  34   a ,  34   b  interconnected by two notches  35   a ,  35   b  in this embodiment, the two arcs  34   a ,  34   b  being respectively provided with two axial reinforcement lateral fins  36   a  supported by two radial rims  37   a ,  37   b  under which extend two axial lateral fins  38   a , the body  33  terminating in the lugs  21   a ,  21   b.          

     To be more precise, the holding plate  31  has an orifice  39  through it centered between the openings  31   a ,  31   b  which, when it is pushed axially by an operator toward the female termination in the direction of the arrow A to reach the locking position shown in  FIG. 7 , not only has its openings  31   a ,  31   b  filled by the underlying edge portions  32   a ,  32   b  but also the orifice  39  through which passes in flush manner an axial locking indicator pin  8  extending between the two bearing surfaces  4   a ,  4   b  of the male termination  1  so that the pin  8  is visibly flush with the external face of the plate  31  to indicate that the locking position has been reached (for example by virtue of a color of the termination  1  contrasting with that of the plate  31 ), this plate  31  then filling the depression  9  provided between the bearing surfaces  4   a ,  4   b  which are then at the same axial level as the plate  31 . 
     As for the connecting lugs  21   a ,  21   b , it is seen in  FIGS. 8 and 9  that they extend downward under respective lower half-flanges  33   a ,  33   b  of the main body  33  situated below the notches  35   a ,  35   b  and that they are adapted to be immobilized in the locking position against the groove  13  by virtue of them being bent by the respective guide and locking aid ramps  7   a ,  7   b . See the aforementioned document EP A1 2 236 894 for a precise description of the lugs  21   a ,  21   b  and the associated ramps  7   a ,  7   b , it being merely pointed out here that the lugs  21   a ,  21   b  are rendered elastically deformable in radial bending by two notches  22  interconnecting them and that the ramps  7   a ,  7   b  are diametrically opposite on the male termination  1  at the same axial height, like the lugs  21   a ,  21   b  that they are adapted to guide axially and constrain radially in the female termination  10 . 
     According to the present invention, the male termination  1  further includes two arms in the form of oblong blades  9 A,  9 B (i.e. they are flat and narrow compared to their length) that extend upward symmetrically to each other from a lower (i.e. axially internal) area of the termination  1  situated at substantially the same axial height as the ramps  7   a ,  7   b , but offset angularly by 90° between two ramps  7   a ,  7   b  (this alternating arrangement of the ramps  7   a ,  7   b  and arms  9 A,  9 B on the circumference of the termination  1  and with the latter that arise at the same height as the ramps  7   a ,  7   b  is visible in  FIGS. 1 ,  2  and  9 ). The arms  9 A,  9 B extend in a substantially axial direction, forming as it were a trident with the termination  1 , and are adapted to occupy:
         a position immobilizing the locking member  30  in which the respective free ends of the arms  9 A,  9 B serve as axial abutments for the member  30  via two internal shoulders  33 A,  33 B formed axially level with and between the half-flanges  33   a ,  33   b  and angularly offset 90° relative to the connecting lugs  21   a ,  21   b  (see  FIGS. 1 and 4 ), in such a manner that the arms  9 A,  9 B form an acute angle α ( FIG. 4 ) with the axis X of the termination  1  in this immobilizing position, and   a position releasing the member  30 , a prerequisite for reaching the locking position, in which the ends of the arms  9 A,  9 B are retracted radially toward the interior of the shoulders  33 A,  33 B only when the male termination is completely inserted in the female termination  10 , because of contact between a boss on each arm  9 A,  9 B and the upper entry end  12  of the female termination  10 , which occurs only at this degree of insertion, with the result that these arm ends no longer form axial abutments for the member  30  (this release position in which the arms  9 A,  9 B are bent parallel to the axis X of the termination  1  is shown in  FIGS. 6 ,  7  and  9 ).       

     As may be seen in  FIG. 4 , it will be noted that the reliability of this immobilizing position, in which the arms  9 A,  9 B form abutments opposing axial sliding of the locking member  30 , is advantageously reinforced by providing for each internal shoulder  33 A,  33 B a width in the radial direction at least equal to that of the end of each arm  9 A,  9 B to obtain a maximized area abutment radial interface. Moreover, each shoulder  33 A,  33 B terminates in a lower axial (i.e. vertical) rim  33 A 1 ,  33 B 1  that is perpendicular to this abutment radial interface and is adapted to be mounted in contact with the external face of the corresponding arm  9 A,  9 B in this immobilizing position. 
     To be more precise, and as may be seen in  FIGS. 4 to 6 , each arm  9 A,  9 B has in a median area of its external face (i.e. that facing away from the axis X of the termination  1 ) the same boss which in this embodiment of the invention is formed of two protuberances  9 A 1 ,  9 B 1  and  9 A 2 ,  9 B 2  that are in the form of parallel ribs or teeth transverse to this arm  9 A,  9 B and which are interconnected by a surface projecting slightly outwards relative to the rest of the arm  9 A,  9 B. Each boss is designed to cooperate with by rubbing on an external (i.e. upper) chamfer  12   a  of the entry end  12  of the female termination  10  only when the male termination  1  is completely inserted in that termination  10 , and it is notably each upper protuberance  9 A 1 ,  9 B 1  that in this embodiment projects furthest which, when it rubs against the oblique surface of the chamfer  12   a , optimizes the bending of the arms  9 A,  9 B by causing them to bend parallel to the axis X of the termination  1  by tilting like a lever. 
     It will be noted that this location of the boss of each arm  9   a ,  9 B with a view to its cooperation with the entry chamfer  12   a  enables some delay in the bending of each arm  9 A,  9 B following its contact with this chamfer  12   a.    
     It will also be noted that in the retracted release position of the arms  9 A,  9 B the two protuberances  9 A 1 ,  9 A 2  and  9 B 1 ,  9 B 2  espouse the entry chamfer  12   a  and the exit chamfer  12   b  of the entry end  12  of the female termination  10  that they surround (see  FIG. 6 ). 
     The rubbing of each boss on the entry end  12  of the female termination  10  advantageously has the effect of significantly increasing for the operator the force for inserting the male termination  1  in the female termination  10  and this rubbing may further generate a “click” audible to the operator, this increased force and/or this click indicating that the correct insertion position of the male termination  1  in the female termination  10  has been reached, thus inviting the operator at this precise moment to maneuver the locking member  30  by pushing it toward the female termination  10  to reach the locking position. 
     It will further be noted that the arms  9 A,  9 B also provide angular guidance for the termination  1  in translation in the female termination  10  to facilitate centering of the lugs  21   a ,  21   b  at the entry to the connecting groove  13 . 
     As shown in  FIGS. 5 to 9 , the lugs  21   a ,  21   b  are locked in the groove  13  of the female termination  10  in the following manner: 
     a) the main body  33  of the member  30  is inserted around the male termination  1  from below after which the holding plate  31  is assembled to the body  33 , in such a manner that the lugs  21   a ,  21   b  are disposed angularly facing the ramps  7   a  and  7   b  and on either side of the arms  9 A,  9 B and that this body  33  abuts axially via its internal shoulders  33 A,  33 B on these arms  9 A,  9 B, thus preventing downward movement of the lugs  21   a ,  21   b  (see  FIG. 5 ), 
     b) the male termination  1  is inserted completely into the female termination  10 , which elastically deforms the arms  9 A,  9 B by bending them because of their boss rubbing against the entry chamfer  12   a  of the termination  10  with the result that the member  30  no longer abuts on these arms  9 A and  9 B radially retracted in this way toward the interior of the shoulders  33 A,  33 B, which allows downward sliding of the member  30  (see  FIG. 6 ), after which 
     c) the locking member is pushed downward (i.e. toward the female termination  10 ) to move the lugs  21   a ,  21   b  into the locking position inside the groove  13  of that termination  10  (see  FIGS. 7 to 9 ). 
     It should be noted that in this locking position the internal shoulders  33 A,  33 B of the member  30  are outside the female termination  10  and that the two lugs  21   a ,  21   b  are immobilized by being bent against the groove  13  and against the associated guide and locking assistance ramps  7   a ,  7   b.    
     To unlock the connecting device and demount it from the groove  13 , upward traction is first applied to the locking member  30 , with the male termination  1  held against the bottom of the female termination  10 , so as to extract the lugs  21   a ,  21   b  therefrom, after which the male termination  1  is extracted from the female termination  10 .