Abstract:
A coupling having means which inhibit separation which is provided for transferring fluid, especially for refueling vehicles. The coupling includes a tubular housing, at least one locking element, in particular, a plurality of expandable collects having an engagement profile for connecting to a correspondingly constructed connection nipple. The coupling also includes a piston, which can be displaced relative to the housing and which can be fixed, especially for being placed on the connection nipple. The piston is subject to the action of a spring opposite of the direction of connection in order to adjust the separation prevention force in relation to the housing of the coupling and is mounted such that it can be displaced opposite of the direction of connection in relation to the locked piston in order to release the engagement of the locking element.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a coupling for transport of gaseous and/or liquid fluids, especially for filling motor vehicles. 
     Especially with such couplings a secure plug-in connection which can be made rapidly should be provided, for the transport of a fluid from a pressure source, for example from a filling station. Safe operation of the connector coupling is important, so that problem-free handling is facilitated, even at high pressures. 
     Such a connector coupling is described in EP-A 0 340 879 of the applicants, where the connector coupling has a housing with a fluid inlet and a fluid outlet, as well as a plurality of valves, in order to ensure reliable sealing of the coupling until the connection is fully made. These valves are actuated in a specific predetermined sequence after fitting the connector coupling, where the outlet valve is first opened by pushing the connector coupling on to a connector nipple, the collet jaws are then closed by further movement of an eccentric control lever and finally the inlet valve is opened. The control lever engages through an eccentric shaft with the slider sleeve for locking the collet jaws and with a central sealing piston, which opens up the fluid inlet after completion of the connection of the plug-in coupling. A secure connector facility is thus provided, since the collet jaws of this coupling are positively locked in the connection position. 
     A similar quick connector is further known frm WO-A 93/20378 of the applicants, wherein collet jaws with an engagement profile are provided in the region of the outlet as the preferred locking elements. A hollow sealing piston which can slide in the coupling housing is also described here and is coupled to an actuating device connected to a sliding sleeve for closing and opening the collet jaws. Operation of the actuating device in the form of an eccentric lever is also necessary here for reasons of safety, in order to be able to release the locking of the quick connector. 
     Such connector coupling have proved themselves in refuelling gas vehicles, on account of their high security. Because of the increasing spread of gas vehicles however, filling up is carried out not only by qualified filling station personnel by also by the driver himself. Accidents have been reported in which the driver has forgotten to release the connector coupling and has thus driven away from the filling station with the gas line attached. The gas line, mostly under pressure, is torn out of its anchorage, so that significant damage, to the vehicle also can result. In addition, substantial amounts of fluid can escape, in spite of suitable safety valves. 
     SUMMARY OF THE INVENTION 
     Accordingly the present invention is based on the object of providing a coupling with a safety breaking device, so that in such events, danger and damage are avoided. 
     The proposed coupling is distinguished by particularly high security, since defined separation of the lines or the connector is achieved, even with high connection pressures, so that exposure danger and damage can be prevented. In particular, in the case of the preferred embodiment for re-fuelling motor vehicles, the possibility of the gas or liquid escaping is safely avoided by the proposed safety breaking device on breaking or release of the connector coupling. This is especially important to protect against accidents but also to protect the environment, since even with break couplings at the “petrol pump” a substantial volume of gas can be lost, which is present in the hose between the filling station and the connector coupling and can escape. 
     It should be noted that the proposed safety breaking device is particularly suitable for connector couplings for various connectors, especially for connector nipples for vehicle refuelling. Because of the compact construction the safety breaking device can even be used as an intermediate coupling in a hose or feed line, for example even at the “petrol pump end”. In the normal case of the connected position, secure engagement of the locking elements, especially the collet jaws is ensured through the piston which can slide in the housing, while even in the exception case of breaking apart with defined release of the collet jaws, the sealed state is ensured by the automatic closing of the outlet valve. The safety breaking device can be constructed relatively simply, so that damage both to the line or coupling side and to the nipple side is reliably avoided. 
     It is particularly important that the release force of this coupling can be adjusted by means of a spring, especially a compression spring in conjunction with suitable dimensioning of piston annular surfaces in an annular chamber, so that reliable and rapid presetting of the break-away force to match the coupling to the current conditions is facilitated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment will now be explained in more detail and described with reference to the accompanying drawings, in which: 
     FIG. 1 is a side view of a preferred coupling for a connector nipple with a connection profile, wherein the coupling is shown in longitudinal half section and in its connected position; and 
     FIG. 2 is a front view of the connector nipple. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of a connector coupling  10  with connection direction A to a connector nipple  30  is shown in FIG.  1 . The connector coupling  10  comprises a tubular housing  11 , here in three parts, where the right end serves as an inlet  12  and the left end as an outlet  13  for feeding on the transported fluid to the connector nipple  30 . The inlet  12  to the housing  11  has a connector adapter  14  which is sealed by a seal  14   a  against the housing  11  (more precisely the housing part  11   a ). The connector adapter  14  also has a thread  14   b  at its end here on the right, to which a hose  1  (or equally a pipeline) is connected to supply the fluid to be transported. The connector adapter  14  can be designed to match the fluid to be transported, especially the currently desired feed angle, through-flow cross-section, etc., being for example bent over. 
     At the end opposite the connector adapter  14 , here the outlet  13 , a plurality of elongated collet jaws arranged in tubular form are provided as locking elements  15 , which are spread apart radially before fitting on to the connector nipple  30 , as is shown for example also in WO-A 93/20378 previously cited. The elongated collet jaws, being the preferred form of a locking element  15 , of which at least three and generally six collet jaws are provided, are hooked at their ends here on the right in an annular groove of a piston extension  22 ′ and are so biased by a garter spring  16  that the collet jaws can be spread radially apart. At the end here on the left at the surface offset to the inside the collet jaws have interlocking engagement profiles  17  match the corresponding connector profile  31  of the connector nipple  30 . On their outside inclined oblique surfaces  21  are provided, which facilitate the breaking operation after reaching a predetermined break-away force, as further described below. 
     In outer locking sleeve  11 C is provided around the collet jaws and is screwed to middle part  11   b  of the cylindrical housing  11 , the latter part in turn being fixed to the housing part  11   a  of the housing  11  to which the connector adapter  14  is fixed, as well as on which an actuating device  18  is mounted. The actuating device comprises an eccentric  19  known per se and a plunger  20 , which can slide a piston  22  (together with its associated piston extension  22 ′) in the direction of the connector nipple  30 , to produce the sealed connection. 
     The piston  22  with its piston extension  22 ′ is guided on the inner peripheral surface towards the outlet  13  of the middle part  11   b  of the housing  11  and has a stepped sealing shoulder  23  for abutment against a seal  32  of the connector nipple  30 . The piston  22 , here in two parts for assembly reasons but fixedly screwed to its piston extension  22 ′, is sealed relative to the collet jaws and the actuating device  18  by sealing rings  24  fitted in the middle part  11   b  of the housing  11 , so that the gaseous and/or liquid fluid flowing essentially along the central axis of the connector coupling  10  cannot escape to the outside. 
     A check valve  25  mounted centrally in the piston  22  is furthermore important and a sealing cone  26  thereof seals against an inner sealing surface  27  on the piston extension  22 ′ in the closed position. The check valve  25  is biased by a compression spring  28 , which is fixed in the piston  22  by means of centring insert  29 , specifically here clamped between the two piston parts  22  and  22 ′ which are screwed together. By means of this check valve  25  it is ensured that the fluid passed through the connector adapter  14  cannot escape in the uncoupled position or break-away position, nor till shortly before the connection of the coupling  10  to the connector nipple  30 , even with the connecting tap at the filling station or the like open. 
     The check valve  25  is, as here shown, opened on fitting the connector coupling  10  on to the connector nipple  30 , as is also a symmetrically arranged sealing cone  33 , where the later is pressed in along the axis of the connector nipple  30  when connecting up and forms a check valve  34  associated with the connector nipple  30 , which is constructed with a constructionally similar centring insert and a compression spring, like the check valve  25 . 
     An annular chamber  40  arranged on the outer periphery of the piston  22  is particularly important, having a spring  41  arranged therein, denoted compression spring  41  below. The compression spring  41  is supported to the left on a shoulder  22   b  of the housing  11  or of the piston extension  22 ′ and acts to the right on a piston annular surface  22   a  on the piston  22 . As can be seen from the drawing, the annular chamber  40  communicates with the inner fluid passage through a radial bore  42 , whereby the housing  11  is maintained in a compensated or balanced position relative to the piston  22 . The piston annular surface  22   a  is pushed by the compression spring  41  up to the inwardly offset region at the plunger  20 , whereby a stop for the displacement of the piston  22  is also provided, especially also with fitted stop sleeves  43  and  44 , whereby a relative axial movement (against the connection direction A) of the components with equalised pressure force to the two sides, needed to release the locking, i.e. relative movement of the housing  11  on the axially locked piston  22 / 22 ′. 
     In the connected position of the coupling  10  the two check valves  25  and  34  are brought into contact with each other on fitting on to the connector nipple  30 , whereby these move substantially simultaneously depending on the spring design in opposite directions. The sealing shoulder  23  also comes into contact with the seal  32 , so that escape of fluid which may be present at the check valve  34  of the connector nipple  30  is avoided. In addition the piston  22  is pushed to the right by the abutment of the sealing shoulder  23  on the seal  32 , until the collet jaws  15  are received in the locking sleeve  11   c  and are held together by the conical bevelled surfaces  21 , i.e. are locked on to the connection profile  31 . 
     The piston  22  is pushed to the right essentially only by the spring force of the (compression) spring  41 , which thus defines the response threshold force of the safety breaking device. In the exception case of breaking apart movement, the housing parts  11   a,    11   b  and  11   c  of the housing  11  are thus drawn by the pulling forces acting on the hose  1  to the right against the spring force of the compression spring  41  and thus free the collet jaws  15  from their blocking position, so that the engagement of their engagement profile  17  on the correspondingly formed connecting profile  31  of the connector nipple  30  is lost, namely through the axial movement of the locking sleeve  11   c  and the freeing in the radial direction along the bevelled surfaces  21 . 
     This movement is not prevented even at very high connection pressures of 1000 bar for example, since the pressure acts to substantially the same extent on the oppositely directed annular surfaces  22   a  and  22   b.  It should be noted that the piston annular surfaces  22   a  and  22   b  are so dimensioned as to their active surfaces that the housing  11  is in a balanced “floating position” relative to the piston  22  (with the associated piston extension  22 ′) locked axially by the collet jaws  15 . Breaking apart security is thus achieved even with increasing fluid pressure and thus particularly reliable safety of the connector coupling  10  is achieved at all pressure ranges. 
     In order to release the connector coupling  10  thus return from the connected position shown in FIG. 1 into the open position, the locking sleeve  11   c  is retracted by means of the actuating device  18 . After a short movement the collet jaws as the preferred locking elements  15  (balls or pins are also possible) can spread apart radially while the piston  22  is similarly pushed here to the left towards the outlet end  13  against the action of the compression spring  41 . Before the sealing contact between the piston  22  and the seal  32  is lost, the check valve  25  preferably provided closes and simultaneously the check valve  34  of the connector nipple  30  also closes. Very rapid closure of the check valves is achieved through this practically simultaneous sequence, so that no volume of fluid can escape. This design also allows safe fitting of the connector coupling  10  on to the connector nipple  30 , where the sealing contact between the seal  32  and the sealing shoulder  23  is ensured, since the open position of the collet jaws  15  is maintained until the connection is produced by the axial displacement of the piston  22  and the consequent entrainment of the piston extension  22 ′. 
     A return feed line  60  fixed to the housing  11  is also important. The return feed line  60  can be plugged in and out of the connector nipple  30  in the connection direction A together with the coupling  10 , to which a mating part  61  with a clip on tab  62  is fixed (see FIG.  2 ). As can be seen from FIG. 1, the clip on tab  62  is preferably fixed in a stable position between two nipple parts, so that secure fixing of the tab  62  results for the break-apart case, while the return feed line  60  can easily be withdrawn from the mating part  61 .