Abstract:
A female element for a quick connection for removably joining pipes of fluid under pressure and which is adapted to receive a male element. The female element includes at least one locking member movable within a guide channel that extends transverse with respect to an axis of fit of the male and female elements and which member has one end which is configured and adapted to be cooperatively engaged in a peripheral groove of the male element. The locking member is also provided with a tab which projects radially with respect to a body of the female element and which is cooperatively engaged by two portions of a control ring that is movable over the body of the female element in order to move the locking member within the guide channel between an inner locking position and an outer release position.

Description:
FIELD OF THE INVENTION 
   The invention relates to a female element of a quick connection as well as to a quick connection for an installation for handling fluid under pressure which comprises, inter alia, such a female element. 
   BACKGROUND OF THE INVENTION 
   In the domain of the removable join of pipes through which a fluid under pressure is conveyed, it is known to use a female connection element which comprises controlled means for locking a male connector in fitted configuration in the female element, i.e. when the pipes are in connected configuration. For example, it is known from U.S. Pat. No. 6,050,298 to use locking balls mounted in the female element and provided to be selectively engaged in an outer peripheral groove of a male connector. 
   The multiple contacts between the balls of the female element and the groove of the male connector during the successive fittings of these elements cause wear and tear and/or a localized deformation which may lead to the creation of beads or of incrustations likely to hinder correct functioning of the connection. Now, in certain applications such as the filling of automobile vehicle tanks with liquefied petroleum gas (LPG), the pressure of the fluid transiting through such a connection may be of the order of 250 bars, this involving considerable stresses on the elements constituting the connection and accelerating the phenomena of wear and tear and/or of deformation, to such a point that the life duration of such a connection may be substantially reduced. 
   It is known, for example from GB-A-2 036 906 or U.S. Pat. No. 3,468,562, to use wedge plates or blocks sliding in oblique directions with respect to the axis of fit of the male and female elements of a connection in order to immobilize these elements in fitted configuration. These wedge plates or blocks are of complex shape. They require sophisticated and expensive machinings. In addition, their shape induces considerable risks of jamming thereof. 
   Furthermore, U.S. Pat. No. 2,433,119 and U.S. Pat. No. 3,188,123 teach using cylindrical detent elements which are more economical than the afore-mentioned wedge plates or blocks. Such detents have a linear bearing surface, along a segment of their generatrix, in the groove of the male element. The radius of curvature of the detents being small, this results in high contact pressures. This bearing surface is therefore subject to rapid wear and tear and induces deformation of the male element. In order to be able to be manoeuvred, such detents must collaborate with two fast, coaxial rings of which one attacks the detents in the vicinity of their front end and the other acts in the vicinity of their rear end. This leads to an excessive radial space requirement. 
   It is a more particular object of the invention to overcome these drawbacks by proposing a novel female quick connection element capable of cooperating with a male element of known geometry, without inducing too much wear and tear or deformation of those parts of these elements used to lock them in fitted configuration. 
   SUMMARY OF THE INVENTION 
   In this spirit, the invention relates to a female element of a secured quick connection, intended for removably joining pipes of fluid under pressure, this element being adapted to receive a male element fitted therein along a longitudinal axis, while being equipped with means for locking this male element in fitted configuration, these means comprising at least one elongated member mobile in translation parallel to an oblique axis with respect to the axis of fit of these elements, while this member is provided with a cylindrical part of which one end is intended to be engaged in a peripheral groove of a male element fitted in the female element. This connection element is characterized in that the afore-mentioned end is defined in part by a bearing surface against a side of the groove and in that the member is provided with a tab projecting radially with respect to an outer radial surface of the body of this female element and which is engaged between two elements in relief inside of a ring controlling the position of the member, this ring being mounted around this body with the possibility of translation parallel to the axis of fit. 
   Thanks to the invention, the elongated locking member or finger efficiently performs its function of blocking a male connector in fitted configuration and may present a geometry avoiding high localized stresses on the male connector, hence a limitation of the wear and tear or deformation induced by the successive manipulations of the connection. The global bearing surface which is distinct from the enveloping surface of the cylindrical part, may come into surface or virtual surface contact on an edge of the groove of the female element, this limiting the wear and tear. The tab allows monitoring of the angular orientation of the cylindrical part of the elongated member about its central axis, this guaranteeing a correct orientation of the bearing surface against the edge of the afore-mentioned groove. In addition, this tab makes it possible to control, thanks to the two elements in relief of the outer ring and by the outside of the body of the female element, the displacements of the elongated member in the two directions, i.e. in the direction of the groove of the female element or opposite thereto. 
   According to advantageous but non-obligatory aspects, a quick connection female element may incorporate one or more of the characteristics of claims  2  to  8 . 
   The invention also relates to a quick connection for an installation handling fluid under pressure which comprises two elements, male and female, and of which the female element is as described hereinabove. 
   Such a connection is more reliable and more long-lasting than those of the state of the art. It finds particularly advantageous application in the domain of filling automobile vehicle tanks, in which case the male element or connector is connected to a pipe supplying a vehicle fuel tank. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood and other advantages thereof will appear more clearly in light of the following description of a female element for a quick connection in accordance with its principle, given solely by way of example, and made with reference to the accompanying drawings, in which: 
       FIG. 1  schematically shows a longitudinal section of a female connection element according to the invention; 
       FIG. 2  is a longitudinal section of a connection according to the invention incorporating the female element of  FIG. 1  during fit of the male and female elements thereof; 
       FIG. 3  is a view similar to  FIG. 2  when the male and female elements are in fitted or coupled position; 
       FIG. 3A  is a view on a larger scale of detail  3 A in  FIG. 3 ; 
       FIG. 4  is a view in perspective and on a larger scale of a locking finger of the female element shown in  FIGS. 1 to 3 ; and 
       FIG. 5  is a view similar to  FIG. 4  showing an alternate embodiment wherein a portion of the locking finger is convex. 
   

   DESCRIPTION OF PREFERRED EMBODIMENT 
   Referring now to the drawings, the quick connection R shown in  FIGS. 2 and 3  comprises a female element A and a male element or connector B, provided to fit in each other in the direction of an axis X-X′ which, in practice, is a longitudinal axis common to elements A and B. 
   The rear part of the female element A is fluidically connected to a first pipe C 1 , while the rear part of the connector B is connected to a second pipe C 2 . The connector B is mounted on an automobile vehicle and the pipe C 2  serves to supply the fuel tank of this vehicle (not shown), with gas under a pressure of the order of 250 bars, while the female element A is connected by the pipe C 1  to a source of fuel under pressure (not shown), for example LPG. In that case, the female element A may equip a service station and be intended to cooperate successively with the male connectors B mounted on different automobile vehicles. 
   The connector B comprises a tubular body  11  on which the pipe C 2  is connected, and defining an internal channel  12  for circulation of fluid. This channel may constitute a housing for a non-return valve (not shown). An O-ring  13  is mounted in an inner peripheral groove  14  of the body  11 . 
   On its outer radial surface  15 , the body  11  is provided with a peripheral groove  16  whose profile is defined by a flat bottom  16   a  and sides  16   b  and  16   c  diverging from the bottom  16   a.  In this way, the bottom  16   a  is cylindrical, while the sides  16   b  and  16   c  are truncated. 
   The connector B is symmetrical of revolution about an axis X B -X′ B  which merges with axis X-X′ when this connector is fitted in the female element A. 
   G 1  denotes the generatrix of the surface of the side  16   c  of the groove  16  which is closest to the end  11   a  of the body  11  intended to be introduced in the element A. This generatrix is rectilinear and oblique with respect to axis X B -X′ B , with an angle of obliqueness α equal to about 45°. The surface generated by the generatrix G 1  is therefore a truncated surface with semi-vertex angle α. 
   The female element A comprises a likewise tubular body  21  on which the pipe C 1  is connected. This body defines a central channel  22  in which is disposed a valve  23  mobile parallel to an axis X A -X′ A  which is a central axis of the element A merged with axis X-X′ when the elements A and B are fitted. 
   The valve  23  is provided with a solid part  23   a  and with a hollow part  23   b , the solid part  23   a  having a cylindri-conical outer surface  23   c  intended to come into abutment against a seat  21   a  formed by the body  21 . An O-ring  24  is installed in an inner groove  25  of the body  21  and is intended to ensure seal with the surface  23   c  or with the outer radial surface  23   d  of the part  23   b.    
   A spring  26  exerts on a flange  23   e  of the valve  23  an elastic effort F 1  tending to apply the part  23   a  against the seat  21   a , i.e. to close the female element A. 
   A ring  30  is mounted around the body  21  and is mobile in translation with respect thereto and parallel to axis X A -X′ A , as presented by arrows F 2  and F′ 2 . 
   Two locking fingers  40  are provided to be partially engaged in the groove  16  of the element B in the fitted configuration shown in  FIG. 3 . 
   Each elongated member or finger  40  is disposed in a housing or guide channel  27  made in the body  21 , the dimensions of the housing  27  being such that the surfaces  27   a  and  27   b  defining the housing may cooperate with the outer surface  40   a  of a cylindrical part  40 A, of straight generatrix and with circular base, of the finger  40  in order to guide this finger in translation. 
   The surface  27   b  forms a stop  27   c  on which a heel  40   f  of the finger  40  comes into abutment, this limiting the movement of the finger towards the channel  22 . The finger  40  is thus captive in the housing  27 . 
   The housing  27  opens out both at the level of the channel  22  and at the level of the volume V defined between the outer radial surface  21   b  of the body  21  and the inner radial surface  30   b  of the ring  30 . 
   The housing  27 , shown on a larger scale in  FIG. 3A , extends in the direction of an axis X 27 -X′ 27  which is oblique with respect to axis X A -X′ A , i.e. to axis X-X′ when the male and female elements are in configuration of fit. β denotes the angle of obliqueness between axes X 27 -X′ 27  and X B -X′ B . This angle is chosen to be equal to angle α. 
   In practice, angles α and β may have values included between 15 and 65°, preferably between 30 and 55°. Satisfactory results have been obtained with a value of α and β equal to 45°. 
   Axes X 27 -X′ 27  and X A -X′ A  are convergent in the direction of the opening  22   a  of the channel  22  through which the connector B is introduced. 
   The finger  40  is provided with an end  40   b  which is intended to project into the channel  22  from the housing  27  in order to be engaged in the groove  16  and which is defined by a truncated and concave surface  40   c,  whose semi-vertex angle, with respect to the longitudinal axis X 40 -X′ 40  of the part  40 A of the finger  40 , is of a value equal to that of β and with radius of curvature similar to that of the surface forming the side  16   c,  with the result that the end  40   b  and the side  16   c  are complementary at the level of the surface  40   c,  this guaranteeing a surface abutment between the finger  40  and the body  11  at the interface  40   c / 16   c.    
   The end  40   b  is also defined by a surface  40   d  in the form of a portion of cylinder, of circular section and of geometry complementary of that of the bottom  16   a  of the groove  16 . 
   It is thus possible to obtain an abutment of the finger  40  in the groove  16  both on its bottom  16   a  and on its side  16   c.  As shown in  FIGS. 3 and 3A , the end  40   b  may be in abutment on the edge  16   c  without interference of the surface  40   d  with the bottom  16   a  due to the fact that the cooperation of the stop  27   c  and of the heel  40   f  limits the centripetal displacement of the enlongated member or finger  40 . Insofar as it does not come into abutment against the bottom  16   a,  the surface  40   d  may have a geometry other than that mentioned hereinabove. It may be flattened, as long as it does not hinder the surface abutment between the surface  40   c  and the edge  16   c.    
   When the finger  40  is in place in the housing  27 , its axis X 40 -X′ 40  merges with axis X 27 -X′ 27 . 
   The finger  40  is also provided with a tab  40   e  projecting radially with respect to the surface  21   b  outside the housing  27  and which is engaged between a shoulder  30   c  made on the inner surface  30   b  of the ring  30  and a secondary ring  31  fast with the ring  30 . 
   In this way, when the ring  30  is displaced towards the rear of the body  21 , i.e. in the direction of the pipe C 1 , by an effort in the direction of arrows F 2  in  FIGS. 2 and 3A , the shoulder  30   c  exerts on a first surface  40   e   1  of the tab  40   e  an effort F 3  which has the effect of displacing the finger  40  in abutment on the surfaces  27   b  and  27   c , this, taking into account the obliqueness of axis X 27 -X′ 27 , inducing a both axial and radial displacement of the finger  40 , parallel to its longitudinal axis X 40 -X′ 40 , to such a point that its end  40   b  is extracted from the groove  16  and from the channel  22 . In that case, the finger does not oppose a withdrawal of the connector B from the channel  22 . 
   When the effort exerted on the ring  30  is released, a spring  32  installed in the volume V exerts on the ring  31  an elastic return effort F 4  which is transmitted, in the form of an effort F 5  exerted on a second surface  40   e   2  of the tab  40   e  opposite the surface  40   e   1 , to each finger  40  which is in that case displaced in the direction opposite the previously mentioned movement in order to attain the position shown in  FIGS. 1 and 3  where it projects into the channel  22 . 
   The surfaces  40   e   1  and  40   e   2  are parallel to each other and substantially radial with respect to axis X A -X′ A , this allowing them to receive in clear cut manner the efforts F 3  and F 5  while being able to slide between the surfaces of the shoulder  30   c  and the ring  31  against which they are in abutment, between the positions respectively shown in  FIGS. 2 and 3 , the distance between parts  30   c  and  31  in that case remaining substantially constant. 
   In the absence of effort exerted on the ring  30  by the user, the effort F 4  also ensures maintenance of the fingers  40  in the configuration of  FIGS. 3 and 3A  where they lock the connector B in fitted configuration in the body  21 . 
   It follows from the foregoing that each finger  40  has a movement of translation represented by double arrow F 6 , controlled solely thanks to the ring  30  and which takes place parallel to axes X 27 -X′ 27  and X 40 -X′ 40 . In particular, it is not necessary to act at the level of the end  40   b  in order to cause the cylindrical part  40 A to slide from its position of  FIG. 3  to that of  FIG. 2 , as the finger  40  is controlled from the rear, i.e. by its side opposite end  40   b.    
   The surface  40   c  allows a surface or virtual surface abutment against the edge  16   c , which is advantageous in terms of wear and tear. Of course, the geometry of the surface  16   c  may be adapted as a function of the geometry of the edge  16   c . It is not necessarily strictly truncated, but substantially truncated. It may equally well be substantially flattened with respect to the surface  40   a , in which case the abutment of the surface  40   c  on the edge  16   c  is a virtual surface abutment insofar as the surfaces adjacent the points of contact are very close to one another. The surface  40   c  may also be convex, as is shown in  FIG. 5 , having a radius of curvature that is greater than that of the surface  40   a,  this avoiding deforming the side  16   c  by the surface  40   c.    
   In all cases, the surface  40   c  is different from the envelope of the part  40 A which defines the surface  40   a,  this allowing it to have a concavity and/or a radius of curvature different from that of this surface  40   a.  The part  40 A may therefore be relatively fine and the housing  27  may be of small volume, but without high contact pressures being generated at the interface between the finger  40  and the body  11 , i.e. between the surfaces  40   c  and  16   c.    
   Taking into account this function of the surface  40   c , the angular orientation of the part  40 A about the axis X 40 -X′ 40  should be monitored in order to guarantee that the surface  40   c  is indeed turned in the direction of the edge  16   c . This objective is attained thanks to the tab  40   e  which, by projecting in the volume V between the elements  30   c  and  31 , avoids the finger rotating about this axis. In other words, the geometry of the elongated member or finger  40  at the tab  40   e  makes it possible to ensure the angular orientation of its cylindrical part  40 A. 
   It is understood that, when it is desired to fit the connector B in the female element A, the effort F 2  may be exerted as shown in  FIG. 2 , this making it possible to disengage the fingers  40  from the channel  22 , the effort of coupling to be exerted being, in that case, principally used for pushing the valve  23  against the pressure prevailing in the upstream part of the central channel  22 . 
   As the rings  30  and  31  extend all around the body  21 , they enable all the fingers  40  sliding in corresponding housings  27  of the body  21  to be controlled simultaneously. 
   It is also possible to fit the elements A and B without acting on the ring  30 , the end  11   a  of the body  11  in that case temporarily pushing the fingers  40  towards the inside of the housings  27 . 
   In the configuration of  FIGS. 3 and 3A , each finger  40  is essentially stressed in compression between the side  16   c  of the groove  16  which exerts an effort F 7  normal with respect to the surface  40   c , and the surface  27   a  which exerts an effort F 8  antagonistic to the effort F 7  and normal with respect to surface  40   a.    
   These efforts F 7  and F 8  may be considerable, particularly as a function of the pressure of the fluid transiting through the connection R, without risk of deformation of the members  11 ,  21  and  40  since the latter are in essentially surface abutment on one another. 
   It should also be noted that the efforts F 7  and F 8  do not induce any effort on the ring  30  which may thus be easily manoeuvred independently of the pressure of the fluid. 
   The surfaces  27   a,    27   b  and the corresponding surface  40   a  of the finger  40  are substantially parallel to axis X 27 -X′ 27 . According to a variant of the invention (not shown), they may be in slight undercut. 
   Axes X 27 -X′ 27  of the housings  27  shown are secant with respect to axis X B -X′ B  or the axis X-X′ of fit at a point P. In a variant, they may be slightly offset with respect to the latter, while conserving their oblique nature. 
   The invention may be implemented with one sole locking finger or with more than two locking fingers, depending on the choice of the person skilled in the art. The fact of using at least two locking fingers makes it possible to distribute the effort of blocking the male connector in fitted configuration about axis X-X′. 
   In all cases, the female element A of the connection is adapted to a standard male element of which a large number may be mounted, for example on automobile vehicles. The invention does not necessitate modifying the male elements already used on automobile vehicles. 
   The invention may be used in domains other than that of filling automobile vehicle tanks, and in general in any domain where a secured connection is sought.