Abstract:
The invention concerns a tubular connection piece for a self-closing connecting device, comprising an end ( 3 ) to be connected to a member, externally provided with elements ( 5 ) for axially locking it in a housing of the connecting device, and internally equipped with a valve ( 33 ) mounted sliding relative to a valve seat ( 37 ) between closing and opening positions and a spring ( 40 ) interposed between a inner flange ( 41 ) of the connection piece and the valve to push the valve into its closing position against the valve seat. The invention also concerns a corresponding connection device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This is the 35 USC 371 National Stage of International Application PCT/FR02/01354 filed on 19 Apr. 2002, which designated the United States of America. 

   FIELD OF THE INVENTION 
   The present invention relates to an endpiece for a self-closing coupling device and to a corresponding self-closing coupling device. Such a device is for coupling together two elements of a circuit for conveying fluid under pressure, such as coupling pipe ends, or more generally, coupling a fluid receiver member such as a tank to a fluid emitter member such as a pump. 
   BACKGROUND OF THE INVENTION 
   Numerous structures are known for coupling devices of this type. 
   One such coupling device generally comprises a tubular body having an internal channel axially subdivided into a first section arranged to receive in leaktight manner an end of a pipe secured to one of the elements that are to be connected together, and a second section having an endpiece fitted therein which is arranged to enable a coupling to be made subsequently to the other element for connection. Between these two sections of the internal channel, the body generally includes an internal shoulder forming a valve seat arranged to co-operate with a valve slide mounted in the internal channel beside the endpiece so as to slide between a closed position in which the valve slide is pressed in leaktight manner against the valve seat, and an open position in which the valve slide is spaced apart from the valve seat so as to define a passage for the fluid. A spring is conventionally interposed between the valve slide and the endpiece to urge the endpiece into its closed position against the valve seat. The manufacture of such coupling devices raises problems, in particular concerning making the valve seat and also assembling the valve which is done by putting successively into place in the body: the valve slide, the return spring, and the endpiece, and which requires handling that is relatively slow and awkward. 
   In order to facilitate assembly operations, it is known to make subassemblies that incorporate the valve slide, the return spring, and the valve seat. Assembly is then performed by initially inserting the subassembly into the internal channel of the body, and then inserting the endpiece which serves to secure the subassembly definitively in the body. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   The invention seeks to propose a solution that constitutes an alternative to those specified above, serving to simplify assembly of the coupling device. 
   To this end, the invention provides a tubular endpiece for a self-closing coupling device, which endpiece includes one end for coupling to a member, is provided on the outside with means for preventing it from moving axially in a housing of the coupling device, and is fitted internally with a valve slide mounted to slide relative to a valve seat between a closed position and an open position, a spring being interposed between an internal shoulder of the endpiece and the valve slide in order to urge the valve slide into its closed position against the valve seat. 
   Thus, the valve seat, the valve slide, the return spring, and the endpiece can be assembled together in a preliminary operation that is simple to perform, thereby providing a subassembly which merely needs to be secured inside the tubular body of the coupling device. As a result, assembly operations become particularly simple and fast. 
   The invention also provides a self-closing coupling device comprising a body having an internal channel formed therein together with an endpiece of the above-specified type which is fitted inside a section of the internal channel. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other characteristics and advantages of the invention appear on reading the following description of a particular, non-limiting embodiment of the invention. 
     Reference is made to the accompanying drawings, in which: 
       FIG. 1  is a longitudinal section view of a coupling device in accordance with the invention, the top half-view showing the valve slide in its open position and the bottom half-view showing the valve slide in its closed position; and 
       FIG. 2  is an elevation view of the valve slide of the coupling device. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference to  FIGS. 1 and 2 , the coupling device in accordance with the invention is for connecting an endpiece  1  (represented by chain-dotted lines in FIG.  1 ), e.g. secured to one end of a pipe that is not shown in the figures, to a member such as another pipe, a fluid-emitter member such as a pump, or a fluid-receiver member such as a tank. 
   Said member is for associating with a tubular endpiece given overall reference  2 , the endpiece having a tapped end portion  3  for receiving a corresponding portion of the member, and an opposite end portion  4  fitted in the coupling device given general reference  6 . The end portion  3  may be provided with coupling means of some other type, such as quick coupling means, snap-fastening means, . . . . The end portion  4  is provided on the outside with an annular rib  5  for co-operating with means for retaining the coupling device. 
   The coupling device  6  comprises a tubular body given overall reference  7  which defines an internal channel given overall reference  8  that is subdivided axially into a section  9  for connection to the member and a section  10  for connection to the endpiece  1 . The sections  9  and  10  are disposed respectively upstream and downstream relative to the direction in which fluid flows through the coupling device. 
   The section  9  includes an end bore  11  which receives the endpiece  2  and which includes means for retaining the endpiece  2 . These retaining means can be seen in FIG.  1  and comprise resilient tabs  12  deformable between a deformed state in which the free end of each resilient tab  12  is clear of the end bore  11  so as to allow the annular rib  5  of the endpiece  2  to pass through during insertion in the tubular body  7 , and a rest position in which the free end of each resilient tab  12  projects into the end bore  11  to bear against the rear face of the annular rim  5  and oppose extraction of the endpiece  2 . Naturally the retaining means may be of any type suitable for ensuring that the endpiece is held axially in the tubular body  7 , for example tapping. 
   The coupling section  10  is itself known. The coupling section  10  defines an end bore  13  for receiving the endpiece  1 . The end bore  13  is provided on the inside with quick coupling means for providing leaktight coupling of the endpiece  1  in the tubular body  7 . In this case, these means comprise longitudinal slots  14  receiving balls  15 , each movable between a retracted position and a position where it projects into the end bore  13 , in which position the balls are designed to project behind an external bead  16  on the endpiece  1 . A locking ring  17  of known type is mounted to turn on the tubular body  7  between a locking position and an unlocking position that are angularly offset relative to each other. For each ball, the locking ring  7  has two housings that are likewise angularly offset relative to each other so as to receive the corresponding ball in each of its two positions, which housings are connected together by means of corresponding ramps for guiding the balls between their two positions. Resilient return means for urging the locking ring  17  into its locked position are preferably mounted between the locking ring and the tubular body  7 . Since these coupling means are themselves known, they are not described in greater detail herein. Naturally, other coupling means could be used, for example a locking ring movable radially between a locking position in which the ring has a portion of inside circumference projecting into the end bore  13 , and an unlocking position in which said portion of inside circumference is taken out from the end bore  13 . Claw coupling means could also be used. 
   The end bores  11  and  13  are connected together via an intermediate chamber  18  connected to the end bores respectively via a shoulder  19  and an annular rib  20  defining an upstream shoulder  21  and a downstream shoulder  22 . The downstream shoulder  22  is for co-operating with the outer annular bead  16  to form an abutment against penetration of the endpiece  1  into the tubular body  7 . 
   The coupling device is a self-closing device comprising a valve slide mounted to slide relative to a valve seat between a closed position in which the valve slide is pressed in leaktight manner against the valve seat, and an open position in which the valve slide is spaced apart from the valve seat so as to define a passage for the fluid. 
   The valve slide, which is described below, is associated with a guide sleeve given overall reference  23 , which sleeve is mounted in the end portion  4  of the endpiece  2 . 
   The guide sleeve  23  comprises an upstream end portion  24  and a downstream end portion  25 . 
   The upstream end portion  24  is received in the end portion  4  of the endpiece  2  and is provided on the outside with a groove  26  receiving an annular sealing ring  27  in close contact with the inside surface of the endpiece  2 , and means for snap-fastening the guide sleeve  23  in the endpiece  2 . In this case, the snap-fastening means are constituted by studs projecting from the outside surface of the upstream end portion  24  and co-operating with corresponding recesses in the inside surface of the endpiece  2 . The guide sleeve can be secured in the endpiece  2  by any means suitable for ensuring that the guide sleeve is prevented from moving axially. 
   The downstream end portion  25  projects from the end portion  4  of the endpiece  2  and is received in the intermediate bore  18 . The downstream end portion  25  is provided on the outside with an annular rib  28  which extends between the terminal face of the end portion  4  of the endpiece  2  and the upstream shoulder  19  so as to form an abutment against insertion of the guide sleeve  23  into the end portion  4 , and a groove  29  which receives an annular sealing ring  30  in close contact with the inside surface of the intermediate bore  18 . The terminal face  31  of this downstream end portion  25  co-operates with the upstream shoulder  21  of the annular rib  20  to define a housing that receives a sealing ring  32  of inside diameter smaller than the outside diameter of the endpiece  1 . 
   The valve slide given overall reference  33  comprises a shutter portion  34  mounted in the endpiece  2  upstream from the guide sleeve  23  and provided with an outer groove  35  receiving a sealing ring  36  which projects from said groove to come into close contact with a concave frustoconical surface  37  of the upstream end portion  24  of the guide sleeve  23  when the valve slide  33  is in its closed position. The concave frustoconical surface  37  thus forms the seat for the valve slide  33 . It should be observed that the upstream flank of the outer groove  35  projects beyond the inner half of the sealing ring  36 , in particular for the purpose of holding the sealing ring  36  firmly against the valve seat when the valve slide  33  is in its closed position, preventing the sealing ring from escaping from the groove. 
   The shutter  34  is extended downstream by a perforated tubular tail  38  which is slidably received in the guide sleeve  23  so as to project beyond it in order to co-operate with a terminal face of the endpiece  1  in such a manner that when the endpiece  1  is inserted into the tubular body  7 , the endpiece  1  brings the valve slide  33  into its open position. It should be observed that the tail  38  is provided with an outer groove  42  which subdivides the outside surface of the tail into two bearing surfaces that are spaced apart so as to limit friction while nevertheless retaining a considerable guide length. The groove may also be used to receive marking in relief. 
   The shutter  34  is associated on the upstream side with a ring  39  mounted to slide in the endpiece  2  and to form a shoulder bearing against one end of a spring  40  whose opposite end bears against an internal shoulder  41  of the endpiece  2 . 
   Thus, the endpiece  2 , the valve slide  33 , the spring  40 , the guide sleeve  23 , and the associated elements form a subassembly which can be assembled together prior to being inserted in the body. This makes it easier to assemble the coupling device of the invention. 
   Naturally, the invention is not limited to the embodiment described and variant embodiments can be applied thereto without going beyond the ambit of the invention as defined by the claims. 
   In particular, the invention may also be made by inverting the moving parts of the structure of the embodiment described. 
   Furthermore, the endpiece of the invention is applicable to any type of coupling device.