Abstract:
Fittings configured as quick-connect couplings or valve assemblies utilize an O-ring to lock a male member within a female member. The O-ring engages a shoulder to both effect a seal and to prevent axial motion of the male member with respect to the female member. In accordance with one embodiment of this invention, pressure within lines coupled by the quick-connect couplings is used to effect locking of the couplings and in accordance with another embodiment, pressure within a container with which the valve assembly is used effects locking of the coupling.

Description:
FIELD OF THE INVENTION 
   The present invention relates to low pressure fittings. More particularly, the present invention relates to low pressure fittings such as low pressure couplings and low pressure valves. 
   BACKGROUND OF THE INVENTION 
   There is a constant need for fittings used to convey and contain fluids. Since there are millions of these fittings used in millions of devices, it is desirable to configure these fittings so that they are both low in cost and reliable. Exemplary of such fittings are low pressure quick-connect fittings, which have replaced threaded fittings in thousands of applications, and valves which vent devices such as pressurized air containers and provide liquid drains for containers. With respect to keeping costs of such fittings as low as possible, there are needs for designs which can been machined, molded or end formed. It is also desirable to have components which are easy and inexpensive to manufacture and which do not require substantial changes in manufacturing know-how. 
   In configuring relatively simple devices, it is also desirable to use components and materials which have been extensively tested and have capabilities which are understood so that the limits of reliability are readily understood. This allows a designer and manufacturer to avoid over designing components so as to minimize manufacturing costs and perhaps spend manufacturing dollars on other aspects of the device using the fitting. 
   SUMMARY OF THE INVENTION 
   In view of the aforementioned considerations and other considerations, the present invention is directed to a fitting for coupling a male member to a female member wherein the female member comprises a receptacle having an inner wall, the inner wall having a shoulder adjacent the opening of the receptacle. The male member has an outwardly opening groove and is received in the female member with a gap therebetween. An O-ring is seated between the groove in the male member in the shoulder of the receptacle to prevent removal of the male member from the receptacle. 
   In a further aspect of the invention the O-ring also seals the gap between the male and female members. In accordance with one embodiment of the invention, the fitting is a quick connect coupling and in accordance with another embodiment of the invention, the fitting is valve assembly. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various other features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
       FIG. 1  is a side elevation of female and male components of a first embodiment a quick connect coupling prior to coupling the components; 
       FIG. 2  is a side elevation of the quick connect coupling of  FIG. 1  showing the components being joined; 
       FIG. 3  is a side elevation of the quick connect coupling of  FIGS. 1 and 2  in coupled together; 
       FIG. 4  is a side elevation of a second embodiment of a quick connect coupling in accordance with the present invention; 
       FIG. 5  is a side elevation of the quick connect coupling of  FIG. 4  but showing ma nd female components after decoupling; 
       FIG. 6  is a perspective view o the components of a fitting in accordance with the preset invention configured as a valve; 
       FIG. 7  is a side view, partially in elevation, of a valve in accordance with the present invention showing components of the valve prior to final assembly; 
       FIG. 8A  is a side elevation showing the components assembled with the valve open; 
       FIG. 8B  is a side elevation oriented 90° to  FIG. 8A ; 
       FIG. 9A  is a side elevation showing the valve in an intermediate position where it is closing; 
       FIG. 9B  is a side elevation oriented at 90° to  FIG. 9A ; 
       FIG. 10A  is a side elevation showing the valve closed; 
       FIG. 10B  is a side elevation oriented at 90° to  FIG. 10A , and 
       FIG. 11  is a side view of an additional embodiment of the valve of  FIGS. 6-10 , wherein the valve is biased to a closed position by a spring. 
   

   DETAILED DESCRIPTION 
   Referring now to  FIG. 1  there is shown a first embodiment  12  of a quick connect coupling in accordance with the present invention having as components a receptacle or female member  14 , a male member  16 , a locking O-ring  18  and primary sealing O-ring  20 . 
   Initially, the female member  14  has the locking O-ring  18  axially positioned in its relaxed state in an inwardly opening groove  22 . The groove  22  has a floor  26  radially extending to side walls  28  and  30 , the wall  30  terminating in an annular edge  31 . Wall  28  begins closer to the axis  32  of the female member  14  and has a wider surface area than the wall  30 . Inboard of the wall  28  there is a frusto-conical stop surface  34  extending from inner cylindrical land  36  of the female member  14  to a tubular member or portion  40 , which may be a tube formed integrally or unitarily with the female member  14 . 
   Extending forwardly from front wall  30  of the inwardly opening groove  22  is a second cylindrical land  42  which has a diameter greater than the first cylindrical land  36  and an axial extent substantially less than the first cylindrical land. The second cylindrical land  42  joins a frusto-conical surface  44  which extends radially inward toward the axis  32  of the female member  14 . The frusto-conical shoulder  44  joins a cylindrical inlet surface  46  which has an inner diameter substantially the same as the inner diameter of the first cylindrical land  36 . 
   The male member  16  has a frusto-conical nose portion  50  and an outwardly opening groove  52  in which the primary sealing O-ring  20  is seated. Groove  52  is joined by a cylindrical portion  54  to a second outwardly opening groove  56 . The second outwardly opening groove  56  has a cylindrical floor  58  and first and second frusto-conical walls  60  and  62  which make the groove  56  concave by flaring away from the cylindrical floor  56 . The male member  16  then continues as a tube  66  which may be integral or unitary with the male member  16 , and in a usual application, has a diameter equal to the diameter of the tube  40  with which the female member  14  is joined. 
   Referring now to  FIG. 2  where the male member  16  is shown being inserted into the female member  14 , it is seen that nose  50  of the male member  16  dilates the elastic O-ring  18  allowing the male member  16  to slide into the female member  14  until the frusto-conical nose  50  abuts the frusto-conical surface  34  on the female member. At this point, the O-ring  18  which has expanded against its elasticity further into the inwardly opening groove  22  then contracts so as to seat in the outwardly opening groove  56  in male member  16 . 
   Upon pressurizing the tube  40  connected to the female member  14 , or upon pressurizing the tube  66  connected to the male member  16  so that there is pressure within the tubes, fluid pressure on the primary O-ring  20  forces the male member  16  to move with respect to the female member in the direction of arrow  70 . Since the locking O-ring  18  is constrained by the outwardly opening groove  56 , the O-ring is forced by the frusto-conical surface  60  to deform against the edge  31  joining the cylindrical land  42  to the second wall of the female member  14 . This causes the O-ring  18  to be squeezed through a gap  72  between the edge  31  on the female member  14  and the frusto-conical surface  60  of groove  56  on male member  16 . 
   As is seen in  FIG. 3 , the locking O-ring  18  then abuts frusto-conical shoulder  44  extending from cylindrical surface  42  to the cylindrical inlet surface  46  which prevents further axial motion of the male member  16  in the direction of arrow  70 . The male member  16  is then permanently locked within the female member  14 . 
   Since the locking O-ring  18  is resilient and deformable, it forms a secondary seal which seals the gap  74  between the male member  16  and the female member  14 . Accordingly, seal  18  for at least some applications is sufficient to both lock and seal the coupling  12 , in which case the seal  20  may be deleted or is considered as an additional sealing O-ring supplementing the sealing action of the O-ring  18 . 
   While utilizing pressure within the tubular portions  40  and  66  to effect coupling the male and female members  14  and  16 , it should be kept in mind that locking should also be effected by simply pulling the male member  16  and female member  14  in opposite directions to move from the  FIG. 2  position to the  FIG. 3  position. 
   Referring now to  FIGS. 4 and 5  where a second embodiment  12 ′ of the quick connect coupling is shown, the radial surface  30 ′, cylindrical land  42 ′, frusto-conical shoulder  44 ′ and cylindrical inlet  46 ′ form part of a stop nut  80  which has external threads  82  which thread into internal threads  84  on the female member  14 ′. Stop nut  80  has radial shoulder  86  which abuts an end  88  on the female member  14 ′. Preferably, coupling of the female member  14 ′ and the male member  16  is accomplished in the same manner as illustrated in  FIGS. 1-3 . While coupling as illustrated in  FIGS. 1-3  is preferable, it is also possible to effect coupling by inserting the male member  16  into the female member  14  prior to threading the lock nut  80  into the end of the female member. 
   The quick-connect coupling of  FIGS. 1-3  is permanent, whereas the coupling of  FIGS. 4 and 5  can be decoupled by removing the stop nut  80  so that the locking O-ring  18  is no longer restrained axially by the frusto-conical shoulder  44 ′. 
   The female member  14 , which can be configured as a receptacle or port as well as a tube, may be machined or molded as is the case with the male member  16 . Optionally, the female member  14  and male member  16  may be formed by stamping. The material may be metal or plastic depending on its application. 
   Referring now to  FIGS. 6-10  where a second embodiment of the fitting is shown, it is seen that the fitting is now configured as a valve assembly  100  comprising three main parts, i.e. a valve stem  102 , a valve body  104  and an O-ring  106 . The valve stem  102  comprises a male member in the form of a plug while the valve body  104  comprises a receptacle or female member. 
   As is seen in the elevational views, the valve body  104  has a bore  110  therethrough defined by a cylindrical inner wall. The bore  110  has a first end  112  and a second end  114 . The second end  114  is relieved to provide a recess  116  having a shoulder  118 . The shoulder  118  is slightly frusto-conical. The valve body  104  has exterior threads  120  thereon threading onto a container or other device which has fluid therein, such as but not limited to pressurized air or a liquid. A hex nut flange  124  having end face  126  is unitary with the valve body  104 . 
   The valve stem or male member  102  has an end flange  130  projecting radially therefrom and a shank portion  132 . The shank portion  132  has outwardly opening groove  134  at second end  135  thereof and a longitudinal opening  138  in the form of an outwardly opening groove. Preferably, there are two grooves  138  disposed at 180° from one another. Grooves  138  have first end  140  which is disposed approximate the annular groove  135  and a second end  142  that communicates with a radial groove  144  in the end flange  130 . 
   In order to assemble the valve assembly  100 , the valve stem  102 , valve body  104  and O-ring  106  are aligned as in FIG.  6  and partially assembled as in  FIG. 7  by inserting the valve stem  102  through the bore  110  of the valve body. As is seen in  FIGS. 8A and 8B , the O-ring  106  is then expanded over the end  136  of the valve stem  104  and seated in the annular groove  135 . 
   The valve assembly  100  shown in  FIGS. 8A and 8B  is then screwed into a wall  150  (shown in dotted lines) of a container or other device which has fluid therein. If the fluid is a pressurized fluid, such as compressed air, pressure against the end face  136  of the valve stem  102  will force the valve stem to move through the intermediate position of  FIGS. 9A and 9B  to the position of  FIGS. 10A and 10B  where the O-ring  106  seats against the frustoconical shoulder  118  of the annular recess  116 . The O-ring seals the gap between valve stem  102  and the wall of bore  110  by abutting and deforming against frusto-conical shoulder  118  and the cylindrical surface  119  and the annular recess  116 . In addition, the O-ring  106  is pressed against the surface  137  which defines groove  135  so that the fluid behind the wall  150  does not escape through the end  140  of the gap  138 . 
   When it is desired to relieve pressure behind the wall  150 , the end flange  130  of the valve is simply pressed back against the face  126  on the valve body  104  so that the space formed by the groove  138  communicates with the space on the opposite side of the wall  150 . This allows air to flow into the annular recess  116  in the valve body  114  and through the axial groove  138  in the shank  132  and radial groove  144  of the male member  102  (see  FIG. 6 ) to exhaust air from behind the wall  150  to a lower pressure, such as that of the surrounding atmosphere. Upon repressurization, the valve stem  102  will again move from the  FIGS. 8A and 8B  to the  FIGS. 10A and 10B  position to close the valve. 
   Referring now to  FIG. 11  where an additional embodiment of the valve assembly  100 ′ is shown, the fitting is similar to that of  FIGS. 6-10  except that a coil spring  160  is disposed in an annular pocket  162  formed in valve body  104 . The coil spring  160  presses against the flange  130  urging the flange to move away from the end face  126  of the valve body  104  to urge the valve assembly  100 ′ to the closed position similar to the closed position of  FIGS. 10A and 10B . Consequently, the valve  100 ′ is automatically in the closed position. If the container is filled with water or a low pressure fluid which may not exert sufficient pressure against the valve stem  102  to urge the valve stem from its open position of  FIGS. 8A and 8B  to its closed position of  FIGS. 10A and 10B , the spring  160  supplies the necessary force to close the valve  100 ′. If it is desired to vent through the valve  100 ′, then the valve stem  102  is pressed back against the end face  126  of the valve body  104  so that the groove  138  is open to the space beyond the valve body  104  and fluid can escape through the axial groove  138  and radial groove  144  into the surrounding environment. 
   From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.