Abstract:
A female snap-on connector ( 1 ) intended to cooperate with a male attachment end fitting ( 20 ) of the type with a central bush ( 26 ) and a flange ( 25 ) includes a body ( 2 ) forming a cylindrical cavity and to which is fixed a cap ( 10 ) forming a housing for two symmetrical latch parts ( 50 ) disposed head-to-spigot, mounted to slide in the same transverse direction, each latch part ( 50 ) including a manoeuvring part ( 51 ), a rigid connecting rod ( 53 ) and a jaw ( 52 ) as well as spring means ( 55 ) for continuously urging each latch part ( 50 ) elastically into its rest position in which the jaw ( 52 ) is moved toward the axis and the manoeuvring part ( 51 ) is in its radially outermost position.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention concerns a female snap-on connector intended to cooperate with a flanged male attachment end fitting. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    In the present document, this combination of male and female members will be referred to as a “connector”. It is standard practice, notably in the automotive industry, to use such snap-on connectors for the fast and demountable connection of a fluid (for example fuel, oil or water) circuit element to another circuit element. The industry has substantially standardized on male end fittings including a cylindrical barrel surrounded by a flange and the female connectors include a cylindrical cavity intended to receive at least the end of the bush and an elastic latch intended to lock the rear of the flange once the latter is in place. O-rings provide the seal around the male end fitting. 
         [0003]    The document EP 0 605 801 A discloses a connector in which the latch is symmetrical and disposed transversely in a latch housing formed between the opening of the cylindrical cavity of the body and a rigid entry ring of the body located at a distance in front of the opening of the cylindrical cavity of the body and fastened to the body. The latch part is an elastically deformable oval or lozenge and includes at two opposite vertices two manoeuvring parts and at two other vertices two jaws. In the rest position, the manoeuvring parts are flush with the exterior envelope of the body so as to be accessible to two opposed fingers of a user. When the user presses these parts radially inward, the latch part is deformed and moves the two jaws laterally away from each other and away from the axis of the body so that the jaws are retracted and release the central region adjoining the periphery of the male end fitting and allow disengagement of the flange and therefore of the male end fitting. 
         [0004]    The lozenge-shaped single latch part proves in use in to be relatively fragile. To allow its elastic functioning, it is necessary to provide connecting parts that are neither too thick nor too rigid but because of this the jaws may be insufficiently retained and not exert on the flange of an end fitting a sufficient force to prevent the end fitting from being pulled out. 
       SUMMARY OF THE INVENTION 
       [0005]    The object of the invention is to improve a connector of this type through a construction enabling greater robustness and an increased resistance of the jaws to pulling out. 
         [0006]    The invention achieves its object thanks to a female snap-on connector intended to cooperate with a male attachment end fitting of the type with a central bush and a flange, the connector including on the one hand a body made from a rigid plastic material and including on one side a tubular portion for connection to a pipe and on the other side a portion forming an open cylindrical cavity intended to receive at least the end of the bush, and a rigid entry ring of the body located a short distance in front of the opening of the cylindrical cavity of the body, while a latch, made from a rigid material and intended to lock behind the flange of the end fitting once the latter is in place in the cylindrical cavity (behind relative to the direction of insertion of the end fitting, but in front referred to the general orientation of the connector), is disposed transversely in a latch housing between the opening of the cylindrical cavity of the body and said rigid entry ring, the latch being symmetrical and including two radially opposed curved jaws adapted to be moved toward or away from each other and the axis of the body by the action of two radially opposite manoeuvring parts that in the rest position are flush with the exterior envelope of the body so as to be accessible to two opposed fingers of a user, the jaws being urged elastically into a close together rest position in which they form a radial abutment behind the flange of the end fitting when the latter is in place, the jaws enabling radial outward retraction of this radial abutment when they are pushed into the moved apart position by the manoeuvring parts when the latter are depressed by the user, characterized in that the latch consists of two symmetrical latch parts disposed head-to-spigot and sliding in opposite senses in the same transverse direction, each latch part being disposed in said transverse direction and including a manoeuvring part orthogonal to said transverse direction rigidly connected by a rigid connection rod to a jaw also substantially globally orthogonal to said transverse direction, sliding means and abutment means being formed in the latch housing to allow head-to-spigot sliding of each latch part over a limited travel between the rest and retracted positions of the jaws, spring means being provided between each latch part and a surrounding bearing member to urge each latch part continuously and elastically into its rest position in which the jaw is moved toward the axis and the manoeuvring part is in its radially outermost position. 
         [0007]    Thanks to this arrangement, each lock part is a part that can be made very robust and the jaws can be very strong. 
         [0008]    The surrounding bearing member referred to above on which bear the spring means that elastically push on each latch part may be an element fixed to the body of the connector. However, in accordance with a preferred feature of the invention, the surrounding member is in fact part of the antagonistic mobile latch part; in this way, when the user presses on the two manoeuvring parts, they reduce the distance between the bearing points of the spring and increase the elastic reaction force twice as quickly. 
         [0009]    More particularly, the spring means of a latch part bear on the one hand on an exterior part of the curved jaw of said latch part and on the other hand on an interior part of the manoeuvring part of the other latch part disposed head-to-spigot. 
         [0010]    The spring mans may be of any type, for example a coil spring placed between the two bearing points. The spring means are more advantageously constituted by a curved leaf spring disposed tangentially on one side of the jaw and progressively diverging therefrom. 
         [0011]    The spring means may be parts separate from the latch part, which simply bear on it or are fixed to it. However, if the jaw is of moulded plastic, the spring is advantageously a curved leaf spring moulded in one piece with the jaw. In fact, the entire latch part may advantageously be moulded. In this case it is advantageous to employ a two-material moulding technique (for example overmoulding or two-material injection moulding) to produce the spring part in a suitable material, more elastic than the material from which the base part of the jaw is moulded. 
         [0012]    The latch housing formed between the opening of the cylindrical cavity of body and the rigid entry ring is advantageously provided by a cap including a cover wall forming said rigid entry ring. This cap is fixed to the front of the body and its cover (or back); it includes a central passage and forms the rigid ring referred to above, which serves as a wall of the latch housing. 
         [0013]    The cap may be fastened to the body by various means, for example by welding, but it is advantageously snap-fastened by means of hooks and attachment members formed on the body and/or the cap or conversely on the cap and the body. The attachment members cooperating with the hooks may be orifices, notches, raised patterns, formed in a wall of the cap. The hooks and the attachment members are advantageously such that demounting the cap is not possible. 
         [0014]    Means for polarizing the cap on the body are advantageously provided, for example by making the cap a different colour to the body. 
         [0015]    The cylindrical cavity of the body advantageously includes a cylindrical first section extending from the opening of the cylindrical cavity to a toroidal rib intended to receive the end of the male end fitting, the cylindrical first section having a diameter greater than that of the male end fitting and accommodating at least an O-ring, a spacer ring and a locking ring. 
         [0016]    Two O-rings are preferably provided, separated by the spacer ring, which is mounted in the cylindrical first section. For its part the locking ring is force-fitted into the cylindrical first section to lock the O-rings and the spacer ring in place. It may have raised patterns, for example splines, on its periphery to facilitate force-fitting it. 
         [0017]    The cylindrical cavity may include steps forming abutments for some of the aforementioned members, for example the locking ring. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Other features and advantages of the invention will emerge from the following description of one embodiment. Reference will be made to the appended drawings, in which: 
           [0019]      FIG. 1  is a perspective view of the connector of the invention in the assembled state. 
           [0020]      FIG. 2  is an exploded perspective view of the connector from  FIG. 1  in the disassembled state. 
           [0021]      FIG. 3  is a view in longitudinal section of the connector from  FIG. 1  in the assembled state with the male end fitting mounted in the connector. 
           [0022]      FIG. 4  is a perspective view of the cap of the connector of the invention shown separately. 
           [0023]      FIGS. 5 and 6  represent in section taken along the line A-A in  FIG. 3  the detail of the mechanism of the two symmetrical jaws of the invention, respectively in the closed rest position and in the open disengagement position. 
           [0024]      FIG. 7  is a diagram representing a latch part and the guide members for the latch part in section and in elevation as seen from the left-hand side of the cap. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0025]    The fast connector  1  essentially includes a body  2  that includes at the rear a tubular portion in the form of a hollow spigot  3  and at the front a cylindrical cavity or chamber  4  in which must be engaged a male end fitting  20  formed of a bush  26  provided with a clip-on flange  25 . The spigot  3  may have on its exterior surface connection profiles, not shown, for example pine tree profiles or single or double bulges, for forcible engagement in a pipe, or may be welded (by rotation, ultrasound, induction or laser welding) to a tube or some other member. A cap  10  is clipped onto the front of the body  2  to form a transverse latch housing to be described in detail later. 
         [0026]    As  FIG. 3  shows, the cylindrical chamber  4  is separated from the interior cylindrical volume of the spigot  3  by a toroidal rib  5  defining a cylindrical passage having an inside diameter adapted to have the distal end  21  of the male end fitting  20  pass through it. The cylindrical chamber  4  is able to receive two O-rings  22  separated by an O-ring spacer ring  23  and a locking ring  24  notched axially at its periphery so as to be engaged forcibly in the chamber  4  and fixed therein flush with the opening of the chamber  4 . To facilitate reading of the drawing, the components  22 - 23 - 22 - 24  are shown separately, but it is to be understood that once assembled they bear one on another. The male end fitting  20  passes through the toroidal members  22 - 24  as its flange  25  bears in the vicinity of the locking ring  24  or even bear on it. A shoulder, not shown, may be formed in the cylindrical cavity for fixing an abutment for locating the locking ring  24 . 
         [0027]    The body  2  includes externally and toward its front portion an enlargement in the form of a square platform  30  with upstanding opposite low walls  31 . A pillar  40  rises toward the front of the body  2  from the two opposite sides of the platform  30  that do not bear the low walls  31 . The chamber  4  also forms at its front mouth a square transverse plate  32 , parallel to the platform  30  but slightly smaller than it. Two snap-fastener hooks  33  are formed on each side on pillars  34  connecting the platform  30  and the plate  32 . 
         [0028]    The cap  10  includes a transverse front cover wall  35  with a central passage  36  through which the male end fitting  20  is able to pass without contact. This wall  35  forms the rigid entry ring of the body referred to at the start of this document. Two opposite lateral walls  37  include openings  38  intended to cooperate with the snap-fastener hooks  33  when the cap is positioned on the front end of the body  2 . The openings  38  are separated by a notch  41  intended to cooperate with the pillars  40  for longitudinal guidance. The opposite plane lateral walls  37  are continued on one side by a quarter-circle wall  39 . 
         [0029]    When the cap  10  is engaged on the front end of the body  2  and clips to it, its cover  35  is immobilized at a certain distance from the plate  32 , forming between these two members a space intended to accommodate the latch. As seen in  FIG. 1 , the low lateral walls  31  partially close the lateral space between the end of the curved wall  39  and the edge of the opposite wall  37 , which leaves two opposite rectangular lateral openings that expose the square manoeuvring button  51  of the locking latch, which in the rest position is flush with the surface of the envelope of the connector (consisting of the body and the cap). In a variant embodiment, the walls  31  may be on the cap  10  instead of on the body  2 , which makes the cap more rigid and increases its resistance to pulling out. 
         [0030]    The latch consists of two identical latch parts  50  cooperating with each other and mounted in their housing, the two parts being mobile in a transverse direction that corresponds to the horizontal direction of the plane of  FIGS. 5 and 6  and to the vertical direction of the plane of  FIG. 3 . They include a curved jaw portion  52  formed by a strong part subtending a circular arc of slightly more than 90° disposed in a transverse plane of the device and globally orthogonal to the direction of transverse sliding of the latch parts. The jaw  52  is connected by a rod  53  to the manoeuvring button  51  which is cantilevered at the end of the rod  53 ; reinforcing ribs  54  make the structure robust. 
         [0031]    Moreover, a curved leaf spring  55  is moulded in one piece with the rest of the latch part  50 . The base  56  of this leaf spring  55  is tangential to the jaw  52  at its end near the rod  53 , and the leaf spring follows at an increasing distance the perimeter of the jaw  52 . The end of the leaf spring  55 , after a change of direction of approximately 90°, comes to bear on an internal face  57  of the manoeuvring button  51  of the other latch part  50  (the antagonistic part) disposed head-to-spigot relative to the first. The leaf spring  55  is prestressed so that its tends to be urged elastically away from the jaw  52  with which it is associated. 
         [0032]    In  FIG. 5 , the two latch parts  50  are in the rest position, symmetrically separated from each other by the maximum distance. In this position of maximum distance between the parts  50  at the level of their manoeuvring buttons  51  the external face of which is flush with the lateral surface of the cap  10 , the jaws  52  are to the contrary in their concentrically closest together position. This rest position is defined by the cooperation of a raised pattern of the parts  50  and two abutments  58  ( FIGS. 4 and 7 ) formed in the cap  10 , inside its cover wall  35 , in the vicinity of the central passage  36 . In this close-together position, the jaws  52  define between them an interrupted ring having an inside diameter between the outside diameter of the male end fitting  20  and that of the flange  25 , so that in the position represented in  FIGS. 3 and 5  the flange  25  is prevented from disengagement toward the front of the connector (toward the rear of the end fitting relative to its insertion direction). It is therefore immobilized axially on both sides, which fixes the end fitting  20  in the connector. 
         [0033]    The guide means for the latch parts  50  are shown diagrammatically in  FIG. 7  (only one of the two latch parts  50  is shown to simplify the figure): there are seen in the vicinity of the central opening  36  of the cover  35  of the cap  10  the two transverse abutments  58  (orthogonal to the walls  37 ) and two slides  59  (parallel to the walls  37 ) that cooperate with the rod  53  of the latch part  50 . The rod  53  slides between the wall  37  and the slide  59 . A recess, not shown, under the rod  53  cooperates with the abutment  58  to define the transverse travel of the latch part  50 . Of course, the travel abutments may be produced by other means. 
         [0034]    If the user simultaneously presses the two pushbuttons  51  of the latches  50 , in the direction of the arrows F in  FIG. 3  or  6 , each of the parts  50  will slide transversely, guided by the slides  59  on cap ( FIG. 4 ). The two parts  50  will move globally toward each other until at the end of travel their ad hoc raised pattern abuts on the abutment  58  but, in doing so, the two jaws  52  will move away from each other, into the position represented in  FIG. 6 , which then, thanks to this retraction, allows the flange  25  to pass in front of the body between the two jaws  52 . During this movement, the springs  55  move elastically toward the curved perimeter of the jaws  52 , continuing to bear on the bearing surfaces  57  inside the opposite pushbuttons  51 . 
         [0035]    It suffices for the user to release the manual pressure on the two pushbuttons  51  for the elastic force of the springs  55  to return the two latch parts  50  to their globally separated position in  FIG. 5 , which is the rest position locking the end fitting. 
         [0036]    As seen in the  FIG. 3  section of the jaws  52 , each arcuate jaw  52  includes a leading portion of small inside diameter forming a conical chamfer  60  followed by a cylindrical enlargement  61  the front face  62  of which forms a transverse abutment shoulder for the flange  25  that also includes toward the front of the connector a substantially transverse abutment face  63  while its rear face  64  is inclined and intended to slide on the leading chamfer  60  of the jaws, which enables the jaws to open automatically on insertion of the end fitting  20 , the end fitting  20  then being retained by virtue of the cooperation of the two transverse faces  63 ,  62  abutted against each other. 
         [0037]    The body  2 , the cap  10  and the latch parts  50  are advantageously made of moulded plastic, and the plastic may be different for the various parts.