Abstract:
A female coupling-half has two pawls ( 7 ) each with a distal detent ( 8 ), to engage the nipple ( 3 ) circumferential groove, and a proximal rounded detent ( 15 ), which can lodge in either a rest closed position ( 16 ) for a closed valve ( 2 ) or a valve-open position ( 17 ). The inserted nipple ( 3 ) moves the valve ( 2 ) which brings with it the pawls ( 7 ) via central projections ( 13 ) thereon and the manual sleeve ( 10 ) until the proximal rounded detent ( 15 ) lodges in its valve-open position ( 17 ). Retraction of the sleeve ( 10 ) for release holds the nipple ( 3 ) in an intermediate pressure relief position until ejection pressure is no longer exerted on the nipple ( 3 ) and the sleeve ( 10 ) is allowed to spring out to its fully extended position completely releasing the nipple ( 3 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a female fluid medium coupling-half suited for coupling together with a standard nipple, as recited in the preamble to the accompanying claim  1 . 
       BACKGROUND ART 
       [0002]    EP 0839298 B1 (having the same inventor) describes a hose coupling suitable for compressed air lines where the female part comprises a valve which opens upon insertion of the male nipple, a displaceable sleeve to open the locked coupling and locking pawls. This coupling is also provided with separate stop elements engaged during decoupling to hold the nipple in an intermediate air pressure releasing position to prevent the nipple from dangerously flying off due to residual pressure. 
         [0003]    EP 0664866 B1 (having the same inventor) discloses a simpler and more effective design of a compressed air safety coupling, which employs pawl elements, each provided with both a proximal and a distal detent, to effect, in conjunction with a specially designed sleeve, both a very effective locking position and an intermediate hold position during residual pressure relief prior to complete release. The particular design described in EP 0664866 B1 demands, unfortunately, certain manual steps in its assembly due to the configuration of the pawl elements, making it difficult or impossible to assemble the female coupler-half using a robot. This coupling is designed for use with European standard nipples [ FIG. 3 ]. The configuration of the pawl elements makes it impossible to use this particular concept described with both nipples of European (longer neck) standard [ FIG. 3 ] and with Asian (short neck) standard [ FIG. 2 ]. 
         [0004]    Long neck (European) nipples, such as that shown in  FIG. 3 , can be paired in certain prior art designs with a female coupling-half which is provided with a protective collar completely covering the exposed end of the manually operated sleeve. This collar prevents inadvertent pulling back of the sleeve should the sleeve stick to something or become obstructed when the coupled hose is pulled. Such a collar completely covering the sleeve end has, in the prior art designs, not been possible except with long neck nipples due to the lack of space. 
       SUMMARY OF THE INVENTION 
       [0005]    Fluid medium couplers, such as pneumatic couplers, typically connect a nipple on the tool side with a female half on the supply side, containing a valve, which opens only when a nipple is inserted, and a spring loaded sleeve, which can be retracted to decouple the two parts. It is often desirable, if not required, to consider two safety aspects when developing a coupler of this type:
       Firstly, retracting the sleeve to decouple the two parts should not permit the nipple part to fly off, due to residual pressure, and cause personal injury or damage. There should be an intermediate holding stage in which residual pressure is let out before full separation of the two parts is possible.   Secondly, it is desirable to have a protective collar around the end of the sleeve of the female half. This protective collar prevents the sleeve from being accidentally retracted, with decoupling as a result. The protective collar prevents an axial, sleeve retracting, force from being applied to the end of the sleeve when the hose is pulled across a floor, for example, or through an environment with obstacles.       
 
         [0008]    These two desirable features are difficult to achieve with known designs for a nipple with a short distance between the circumferential groove and the abutment face of the nipple, such as is the case in the CEJN 315 Series standard nipple [shown in  FIG. 2 ], or the Nitto Kohki Co. Ltd. Hi-Cupla plug, which will be referred to in the following as the Asian standard compressed air nipple. It has not been possible to achieve these safety features in the short space available according to Asian standard, nor has it been possible to achieve satisfactory strength and wear resistance in this short coupling. The female coupling half should be no longer than existing Asian standard female coupling halves. None of these desirable features is achieved at present in any female coupling-half design applicable to the short neck Asian nipples for compressed air couplings. A female hose coupling-half as described in the preamble to the accompanying claim  1  which has the characterizing features of the accompanying claim  1  achieves both of these advantages in an inventive manner. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention will be described with reference to a non-limiting example shown in the accompanying drawings, of which: 
           [0010]      FIG. 1  shows the female coupler-half according to the invention in its decoupled state, 
           [0011]      FIG. 2  shows a compressed air nipple of Asian (short neck) standard. 
           [0012]      FIG. 3  shows, in contrast, an alternative nipple of European (long neck) standard, which is not employed in this example. 
           [0013]      FIG. 4  shows a pawl, two of which are employed in the embodiment of the present invention. 
           [0014]      FIG. 5  shows by itself a metal tube, which in the assemble coupling-half, surrounds the valve and is, in turn, surrounded by the decoupling sleeve. 
           [0015]      FIG. 6  shows on the left a knurled, manually operated decoupling sleeve which, after assembly, surrounds the female coupler-half assembly to the right in the figure. 
           [0016]      FIGS. 7-9  show successive steps of the coupling insertion of the nipple into the female coupling-half according to the invention. 
           [0017]      FIG. 10  shows the intermediate pressure relief nipple hold position upon manual retraction of the knurled sleeve for decoupling. 
           [0018]      FIG. 11  shows the complete release of the nipple during decoupling. 
           [0019]      FIG. 11   b  shows the female coupling-half after removal of the nipple with the sleeve  10  in its original position. 
           [0020]      FIG. 12  is an exploded view of a female coupler half according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The figures will refer primarily to a single non-limiting example, designed for a safety coupling for use with an Asian standard short-neck compressed air hose nipple, as shown in  FIG. 2 . Only a single exemplary embodiment of the female coupling-half of the invention is shown in the drawings and there is uniform numbering of each element throughout the drawings. 
         [0022]      FIG. 1  shows a female hose coupling-half suitable for use with a short neck Asian standard nipple. A valve  1  has a hollow body  2  [shown in longitudinal section in  FIG. 6 ] with openings  23  and at its end a rubber O-ring  21 . There is a surrounding ring  20  against which the rubber O-ring  21  seals to close the valve. The valve  1  is also provided with a cylindrical socket for receiving the end of a short-neck Asian standard nipple  3 . The valve is spring-biased  22  to the right in the drawing to keep the valve  1  of female hose coupling-half, which is connected to the supply of compressed air, closed when no nipple has been completely inserted. 
         [0023]    A tube  4  slidably holds the valve  1  and is integral in this example with a protective collar  5 , to protect against inadvertent release, as will be explained in more detail below. The tube is in turn surrounded by a manually operated spring  24  biased sleeve  10 . Said tube  4  is shown alone in  FIG. 5  and is provided in this example with two longitudinal slots  6 , disposed in diametric opposition. (See  FIG. 12  as well). Each of these slots  6  holds a pawl  7 , with a distal (to the right in  FIGS. 1 ,  4 - 11 ) detent  8  which engages a circumferential nipple groove to hold the nipple in either a fully coupled compressed air delivery position or an intermediate holding position for pressure relief prior to complete disengagement, as will be described below. Each pawl  7  has a proximal (to the left in  FIGS. 1 ,  4 - 11 ) detent  15 , which is rounded to be able to slide, when not held down by the interior of the sleeve  10 , between a distal and a proximal depression  16  and  17  respectively crossing each slot  6 . Each pawl has a central projection  13 , which rests in a circumferential groove  14  in the valve body  1  and forms a fulcrum about which the pawl can see-saw to bring the detents  8 , 15  in and out of engagement, as will be described in more detail below. This see-saw action is crucially important in significantly increasing the wear strength and life of the components over previous designs, particularly in view of the interaction between brass and steel components. Each pawl is also provided with a radially outward heel  18  near its distal end. 
         [0024]    The spring-biased  24  sleeve  10  surrounding the tube  4  can be manually actuated for decoupling. The interior of the sleeve is provided with two circumferential cavities  11  and  12  [see  FIG. 6 ], which permit the detents to see-saw in and out of engagement, in various axial positions of the sleeve  10 . 
         [0025]    The inventive female coupling-half functions as follows together with the short neck hose nipple of Asian standard. A hose nipple  3  is seen in  FIG. 7  being inserted into the female coupling-half of the invention. The sleeve  10  is still in its forward spring-biased position, as is the valve  1 , keeping the compressed air supply closed. The incoming (see arrow B 1 ) head of the nipple pushes the distal detent  8  of each pawl  7  radially outwards. This is permissible because the sleeve  10  is in its completely forward position with its distal cavity  11  aligned with each heel  18 , which can now enter the distal cavity  11 , permitting the nipple to enter the cylindrical socket in the body  2  of the valve  1 . As the user continues to push the nipple  3  into the female coupling-half, the valve body  2  is forced to the left in the drawing against the force of the spring  22 , thereby opening the supply of compressed air into the nipple and its hose (not shown). [See FIG.  9 .] The movement of the valve body  2  also brings with it the two pawls  7  because of the engagement between the groove  14  and the projection  13  on each pawl  7 . This movement of each pawl is shown in  FIG. 8  with the proximal rounded detent  15  sliding from the distal depression  16  towards the proximal depression  17  in the outer surface of the tube  4 . The interior proximal cavity  12  in the sleeve  10  has a circumferential oblique surface  19  at its proximal end. The sleeve  10  will move slightly to the left as shown in the figures but this oblique surface will force the proximal detent  15  into the proximal depression  17  in the tube  4  and the sleeve will return (Arrow A 1 ) to its original extended position as shown in  FIG. 9 , which shows the coupling in its fully engaged locked position, holding the proximal detent  15  and thus the pawl  7  in its locked position. This locked position utilises both of the detents and the projection  13 , all securely held in a firm locking position by the interior surfaces of the sleeve  10 . 
         [0026]    The person skilled in the art will of course understand that the cavities  11  and  12  can be altered in diameter and shape within the scope of the invention, achieving the same effects. 
         [0027]    To decouple, the user must pull back on the sleeve  10 , whereby the proximal detent  15  of the pawl  7  can slide up and into the distal depression  16  of the tube  4  and the spring  22  of the valve will push the body  2  of the valve forward thus closing the valve as shown now in  FIG. 10 . In this position [ FIG. 10 ], the nipple has moved in the direction of the arrow B 2  but is still held by the sleeve  10 , the pawl  7  and the distal detent  8  of the pawl  7 , while the residual pressure is released since the nipple has moved slightly out of sealing engagement with the valve socket. This prevents high residual pressure from launching the hose nipple or the female coupling half at high speed, resulting in possible injury to persons or damage. The final extraction of the nipple is only possible when the sleeve  10  has been let go of, after pressure relief, and it returns to its original extended position as shown in  FIG. 11 , permitting the nipple to exit from the female part. As a further safety feature, the sleeve  10  will not return to its original position as shown in  FIG. 11  until there is no longer high pressure trying to expel the nipple, even though the operator has released the sleeve  10  from his grip. The nipple will be held in the intermediate pressure relief position, even if the operator lets go of the sleeve as long as there is high pressure in the system. This function can be understood by viewing  FIG. 10 , wherein we suppose there is a strong residual pressure pushing the nipple in the direction of the arrow B 2 . The edge of the circumferential grove will press against the distal detents  8  thus keeping the heels  18  of each pawl  7  in contact with the sleeve  10 , keeping the sleeve from advancing to its extended original position [ FIG. 11 ], where the interior circumferential cavity  11  now gives space to the heels  18  so that the distal detents  8  will completely release the nipple. 
         [0028]    For better understanding of the components of the exemplary coupler half of the invention,  FIG. 12  shows an exploded view. The tube  4  is provided with a threaded portion  4   a  at its end for screwing into interior threads  21   a  in pipe fitting  21 , to thus hold the entire coupling-half assembly together for use. The spring  22 , mounted between the sleeve  10  and the pipe fitting  21 , biases the sleeve  10  to its position to the right in  FIG. 1  for example. 
         [0029]    This novel arrangement with the projections engaging the body of the valve permits the arrangement of a protective collar  5  on the tube. The protective collar prevents inadvertent retraction of the sleeve, and decoupling, should the hose and coupling be pulled and become stuck in some impediment on the floor for example. 
         [0030]    Although the present invention has been illustrated here as used with a pneumatic system, the skilled art worker will recognize that it can, with proper adaptation, be applied, within the scope of the appended claims, in different types of fluid medium delivery systems, i.e. gas and liquid delivery systems, such as for breathing air and oxygen, high pressure systems and hydraulic systems.