Abstract:
A coupling member is disclosed which includes a valve device that is axially movable between an open position and a closed position where the valve device closes an annular valve opening defined an outer valve seat portion and an inner valve seat portion. The valve device includes an outer annular sealing member and an inner annular sealing member. The inner annular sealing member includes an annular extending portion configured such that, when the valve device approaches the closed position, the annular extending portion sealingly engages the inner valve seat portion and is elastically bent to allow the valve device advance further to the closed position so that the outer annular sealing member positively engages the outer valve seat portion.

Description:
BACKGROUND OF THE INVENTION 
     I. Technical Field 
     The present invention relates to a coupling member for a pipe coupling, and more particularly, to a coupling member including an inner valve seat member disposed in the radially central portion of a cylindrical coupling body, an outer valve seat member disposed on an inner peripheral surface of the coupling body at a position corresponding to that of the inner valve seat member, and a cylindrical or annular valve member disposed in the coupling body and being displaceable in an axial direction between a closed position where the valve member engages with the inner and outer valve members to close a fluid passage of the coupling body and an open position where the valve member is apart from the inner and outer valve members to open the fluid passage. 
     II. Description of the Related Art 
     Male and female coupling members for a pipe coupling are generally provided, in a cylindrical coupling body thereof, with a valve device for opening and closing a fluid passage. There are various types of valve devices. One example is a valve device in which a cylindrical valve member is slidable along an inner peripheral surface of the coupling body, a valve seat member is disposed at the radially central position of the cylindrical body, and the valve member sealingly engages with the valve seat member to close the fluid passage when the valve member is at a fluid passage closed position. In this type of coupling member, a sealing member such as an O-ring is disposed between an outer peripheral surface of the valve member and the inner peripheral surface of the cylindrical body, thereby preventing a fluid from leaking from a gap between the male and female members (for example, U.S. Pat. No. 4,936,345). In another example, instead of using a sealing member, a valve member itself is formed of rubber or the like to also to be adapted as a sealing member (for example, Japanese Unexamined Utility Model Registration Application Publication No. 64-49791). 
     SUMMARY OF THE INVENTION 
     However, coupling members which are configured to prevent leakage in the above-described manner have the following problem. 
     When the valve member is at the fluid passage closed position, the valve member sealingly engages with the outer and inner valve seat portions, more specifically, annular outer and inner sealing members are sandwiched between respective the outer and inner valve seat portions and the valve member, whereby sealing is provided. However, in terms of manufacturing, it is difficult that the valve member begins to press the outer and inner sealing members simultaneously. Therefore, one of the sealing members may be pressed earlier than the other sealing member, and thus the movement of the valve member may be stopped before the other sealing member is pressed enough to provide a proper sealing effect. 
     The object of the present invention to provide a coupling member which can solve such a problem. 
     The present invention provides a female coupling member including a cylindrical coupling body ( 34 ) having a male member receiving portion (indicated by reference numeral  30  in the embodiment described later) and a fluid passage portion ( 32 ) communicating with a fluid passage of a male coupling member ( 14 ) received into the male member receiving portion ( 30 ), and a valve device which is disposed in the coupling body to open and close the fluid passage portion ( 32 ). The valve device includes an outer valve seat portion ( 38 ) projectingly formed on an inner peripheral surface of the coupling body so as to surround the male member receiving portion ( 30 ); an inner valve seat portion ( 42 ) forming an annular valve opening ( 40 ) between the outer valve seat portion ( 38 ) and the inner valve seat portion in the coupling body ( 34 ); an annular valve member ( 44 ) disposed in the coupling body ( 34 ) so as to be displaceable in the axial direction thereof between a closed position ( FIG. 1 ) where the valve member engages with the outer and inner valve seat portions ( 38 ,  42 ) to close the valve opening ( 40 ) and an open position ( FIG. 2 ) where the valve member is displaced in the axial direction away from the male member receiving portion  30  toward the fluid passage portion ( 32 ) to be apart from the outer and inner valve seat portions to open the valve opening; a spring ( 46 ) for biasing the valve member ( 44 ) in the axial direction toward the closed position; an outer annular sealing member ( 56 ) mounted on and around the valve member ( 44 ), the outer annular sealing member ( 56 ) being configured to be moved without contact with the coupling body ( 34 ) when the valve member ( 44 ) is moved between the closed position and the open position and to be forced against the outer valve seat portion ( 38 ) in the axial direction by the spring ( 46 ) to seal between an outer peripheral surface of the valve member ( 44 ) and the outer valve seat portion ( 38 ) the valve member ( 44 ) is at the closed position ( FIG. 1 ); and an inner annular sealing member ( 60 ) having a fixed portion ( 60 - 1 ) fixedly attached to the valve member ( 44 ) on a radially outer side with respect to the inner valve seat portion ( 42 ) and an annular extending portion ( 60 - 2 ) extending radially inward beyond an annular surface (embodied as a cylindrical surface  42 - 1  in the embodiment), which defines the valve opening ( 40 ), of the inner valve seat portion ( 42 ), wherein, when the valve member ( 44 ) is moved from the open position toward the closed position and approaches the closed position such that the valve member ( 44 ) advances into the annular valve opening ( 40 ), the annular extending portion ( 60 - 2 ) of the inner annular sealing member  60  is sealingly engaged with the inner valve seat portion ( 42 ) and, upon further advancement of the valve member ( 44 ), is elastically bent while maintaining the sealingly engagement to allow the valve member ( 44 ) to reach the closed position while the annular extending portion ( 60 - 2 ) remains outside the annular valve opening  40 . The inner annular sealing member configured to be moved without contact with the coupling body when the valve member is moved between the closed position and the open position. 
     Specifically, the outer annular sealing member ( 56 ) can be disposed on the outer peripheral surface ( 54 ) of the valve member. 
     In this female coupling member, when the valve member comes to the closed position and then the outer annular sealing member ( 56 ) is sandwiched between the outer peripheral surface of the valve member and the outer valve seat portion ( 38 ), the inner annular sealing member ( 60 ) engages with the inner valve seat portion ( 42 ) and is elastically deformed so as to be bent, thereby being pressed against the inner valve seat portion for sealing between the inner valve seat portion and the inner peripheral surface of the vale member. Therefore, the outer annular sealing member can be pressed enough to provide a proper sealing effect even after the inner annular sealing member has engaged with the inner valve seat portion. 
     Specifically, the inner peripheral surface of the valve member includes an annular axially-extending surface ( 54 - 4 ) which is advanced along the annular surface defining the valve opening, of the inner valve seat portion when the valve member comes to the closed position ( FIG. 1 ) and an annular radially-extending surface ( 54 - 5 ) extending radially more outward on the side of the open position with respect to the annular axially-extending surface. The inner annular sealing member ( 60 ) has a fixed portion ( 60 - 1 ) fixedly attached to the valve member on the side of the open position with respect to the annular axially-extending surface ( 54 - 4 ) of the valve member, and an extending portion ( 60 - 2 ) configured to extend from the fixed portion along the annular radially-extending surface of the valve member to the radially inner side, and radially inward with respect to the annular axially-extending surface ( 54 - 4 ) of the valve member. When the valve member comes to the closed position, and when the annular axially-extending surface of the valve member is advanced to the inner side of the annular surface of the inner valve seat portion with the outer annular sealing member ( 56 ) being pressed against the outer valve seat portion, the extending portion ( 60 - 2 ) engages with the inner valve seat portion, and then, is bent, thereby being elastically deformed so as to move away from the annular radially-extending surface of the valve member. 
     Specifically, when the valve member comes close to the closed position, the extending portion ( 60 - 2 ) engages with the inner valve seat portion, and then the outer annular sealing member ( 56 ) engages with the outer valve seat portion. Then, as the valve member comes further closer to the closed position, the extending portion ( 60 - 2 ) is bent and elastically deformed so as to move away from the annular radially-extending surface ( 54 - 5 ) of the valve member with the outer annular sealing member being pressed against the outer valve seat portion. 
     More specifically, the extending portion ( 60 - 2 ) of the inner annular sealing member ( 60 ) is configured to engage with the inner valve seat portion ( 42 ) first in order that a sufficient sealing effect is provided between the inner peripheral surface of the valve member and the inner valve seat portion by the time the outer annular sealing member ( 56 ) is sandwiched between the outer peripheral surface of the valve member and the outer valve seat portion to provide a sealing effect. 
     The present invention also provides a female coupling member including a cylindrical coupling body having a male member receiving portion ( 30 ) and a fluid passage portion ( 32 ) communicating with a fluid passage of a male coupling member ( 14 ) received into the male member receiving portion ( 30 ), and a valve device which is disposed in the coupling body to open and close the fluid passage portion ( 32 ). The valve device includes an outer valve seat portion ( 38 ′) projectingly formed on an inner peripheral surface of the coupling body ( 34 ) so as to surround the male member receiving portion ( 30 ); an inner valve seat portion ( 42 ′) forming, an annular valve opening ( 40 ) between the outer valve seat portion ( 38 ′) and the inner valve seat portion in the coupling body; an annular valve member ( 44 ′) disposed in the coupling body so as to be displaceable in an axial direction thereof between a closed position where the valve member engages with the outer and inner valve seat portions to close the valve opening and an open position where the valve member is apart from the outer and inner valve seat portions to open the valve opening; a spring ( 46 ) for biasing the valve member toward the closed position; an inner annular sealing member ( 60 ′) for sealing between the inner peripheral surface of the valve member and the inner valve seat portion by being sandwiched between the inner peripheral surface and the inner valve seat portion when the valve member is at the closed position; and an outer annular sealing member ( 56 ′) which is fixedly attached to the valve member on the radially more inner side with respect to the outer valve seat portion and extends radially outward beyond an annular surface ( 38 ′- 1 ) defining the valve opening of the outer valve seat portion, and which engages with the outer valve seat portion and is elastically deformed so as to be bent when the inner annular sealing member is sandwiched between the inner peripheral surface of the valve member and the inner valve seat portion, thereby being pressed against the outer valve seat portion for sealing between the outer valve seat portion and an outer peripheral surface of the valve member. 
     In this female coupling member, the construction of the outer annular sealing member and the outer valve seat portion and the construction of the inner annular sealing member and the inner valve seat portion are reversed compared with the above-described female coupling member. This construction can be as effective as that of the one described above. 
     Further, the present invention provides a female coupling member including a cylindrical coupling body ( 34 ) having a male member receiving portion ( 30 ) and a fluid passage portion ( 32 ) communicating with a fluid passage of a male coupling member ( 14 ) received into the male member receiving portion ( 30 ), and a valve device which is disposed in the coupling body to open and close the fluid passage portion ( 32 ). The valve device includes an outer valve seat portion ( 38 ″) projectingly formed on an inner peripheral surface of the coupling body ( 34 ) so as to surround the male member receiving portion ( 30 ); an inner valve seat portion ( 42 ″) forming an annular valve opening between the outer valve seat portion and the inner valve seat portion in the coupling body; an annular valve member ( 44 ″) disposed in the coupling body so as to be displaceable in the axial direction thereof between a closed position where the valve member engages with the outer and inner valve seat portions to close the valve opening and an open position where the valve member is apart from the outer and inner valve seat portions to open the valve opening; a spring ( 46 ) for biasing the valve member toward the closed position; an inner annular sealing member ( 60 ″) which is fixedly attached to the valve member on the radially outer side with respect to the inner valve seat portion and extends radially inwardly beyond an annular surface ( 42 ″- 1 ), defining the valve opening, of the inner valve seat portion, and which, engages with the inner valve seat portion and is elastically deformed so as to be bent when the valve member is at the closed position, thereby being pressed against the inner valve seat portion for sealing between the inner valve seat portion and an inner peripheral surface of the valve member; and an outer annular sealing member ( 56 ″) which is fixedly attached to the valve member on the radially inner side with respect to the outer valve seat portion and extends radially outward beyond an annular surface ( 38 ″- 1 ), defining the valve opening, of the outer valve seat portion, and which engages with the outer valve seat portion and is elastically deformed so as to be bent when the valve member is at the closed position, thereby being pressed against the outer valve seat portion for sealing between the outer valve seat portion and an outer peripheral surface of the valve member. 
     In this female coupling member, the above-described characteristic valve structure is applied to the inner and outer sealing members, which enables proper sealing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of a pipe coupling according to the present invention, showing a state in which a female coupling member and a male coupling member are separated from each other. 
         FIG. 2  shows a state in which the female coupling member and the male coupling member are coupled to each other. 
         FIG. 3   a  is a sectional view of the female coupling member in a state in which the coupled male coupling member is being pulled out, showing a state in which a valve device has begun to move back to a closed position and an inner annular sealing member has come into contact with an inner valve seat portion. 
         FIG. 3   b  is a partial sectional view showing an enlarged principle part of  FIG. 3   a.    
         FIG. 4   a  is a view like  FIG. 3   a , but showing a state in which the valve device has come to the closed position. 
         FIG. 4   b  is a partial sectional view showing an enlarged principle part of  FIG. 4   a.    
         FIG. 5   a  is a view like  FIG. 4   a , but showing a state in which the inner annular sealing member has been further elastically deformed by a fluid pressure in the female coupling member. 
         FIG. 5   b  is a partial sectional view showing an enlarged principle part of  FIG. 5   a.    
         FIG. 6  shows a modification of the attachment structure of the inner annular sealing member. 
         FIG. 7  shows another modification of the attachment structure of the inner annular sealing member. 
         FIG. 8  is a sectional view showing a principle part of a female coupling member according to another embodiment. 
         FIG. 9  is a sectional view showing a principle part of a female coupling member according to another embodiment. 
         FIG. 10  is a sectional view showing a principle part of a female coupling member according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The followings describe embodiments of a female coupling member according to the present invention. 
       FIG. 1  shows a female coupling member  12  according to the present invention and a pipe coupling  10  including a male coupling member  14 . 
     The male coupling member  14  includes a cylindrical coupling body  20 , a valve member  22  for opening and closing a fluid passage  21  of the coupling body, a support member  24  for supporting the valve member displaceably in an axial direction of the coupling body, and a compression spring  28  for pressing the valve member  22  against a valve seat  26  formed on the inner side of an end opening of the coupling body. 
     The female coupling member  12  includes a male member receiving portion  30 , a cylindrical coupling body  34  having and a fluid passage portion  32  communicating with the fluid passage of the male coupling member  14  received into the male member receiving portion  30 , and a valve device  36  which is disposed in the coupling body and which opens and closes the fluid passage portion. 
     As clearly shown in  FIGS. 3   a  to  5   b , the valve device  36  includes an outer valve seat portion  38  projectingly formed on an inner peripheral surface of the coupling body  34  so as to surround the male member receiving portion  30 , an inner valve seat portion  42  forming an annular valve opening  40  between the outer valve seat portion  38  and the inner valve seat portion in the coupling body  34 , a valve member  44  disposed in the coupling body  34  so as to be displaceable in an axial direction thereof between a closed position ( FIG. 1 ) where the valve member engages with the outer and inner valve seat portions  38 ,  42  to close the valve opening  40  and an open position ( FIG. 2 ) where the valve member is apart from the outer and inner valve seat portions  38 ,  42  to open the valve opening, and a compression spring  46  for biasing the valve member  44  toward the closed position. 
     Specifically, the coupling body  34  is composed of a first cylindrical member  48  having the male member receiving portion  30 , and a second cylindrical member  50  coupled to the first cylindrical member  48 . The inner valve seat portion  42  is formed on the outer periphery of the closed front end (right end in the figure) of the second cylindrical member  50 . A communicating passage  52  is formed in the side wall of the second cylindrical portion  50 , and a hose (not shown) is connected to the rear end (left end) of the second cylindrical portion. 
     As for the valve member  44 , an outer annular sealing member  56  is provided on an outer peripheral surface  54  thereof and the inner annular sealing member  60  is provided on an inner peripheral surface  58 . 
     The outer peripheral surface  54  includes an inclined surface  54 - 1  generally parallel to an inclined surface  62  of the outer valve seat portion  38 , a cylindrical surface  54 - 2 , which extends forward from the front end of the inclined surface (rightward in the figure) adjacently to the cylindrical inner peripheral surface  64  inside the cylindrical inner peripheral surface  64  (forming the opening  40  between the inner valve seat portion  42  and the cylindrical inner surface) of the outer valve seat portion  38 , and a cylindrical surface  54 - 3  extending rearward from the rear end of the inclined surface  54 - 1  so as to be adjacent to an inner peripheral surface of the first cylindrical member  48 . The inclined surface  54 - 1  is biased toward the inclined surface  62  of the outer valve seat portion  38  by means of the compression spring  46 . The outer annular sealing member  56  is accommodated in a seal accommodating groove  66  formed on the inclined surface  54 - 1 . The seal accommodating groove  66  may be formed on the inclined surface  62 , instead of the inclined surface  54 - 1 , to accommodate the outer annular sealing member  56 . 
     The inner peripheral surface  58  includes a first radially-extending surface  54 - 5 , a second cylindrical surface  54 - 6 , a second radially-extending surface  54 - 7 , and a third cylindrical surface  54 - 8 , which are disposed adjacently to the cylindrical surface in the above order from a first cylindrical surface  54 - 4  toward the rear, on the radially outer side with respect to a cylindrical surface  42 - 1 , which defines the valve opening  40  of the inner valve seat portion  42 . The inner annular sealing member  60  has a fixed portion  60 - 1  fixedly attached to the second cylindrical surface  54 - 6  and an annular extending portion  60 - 2  extending radially inward from the fixed portion. The extending portion  60 - 2  extends inwardly beyond the cylindrical surface  42 - 1  of the inner valve seat portion  42 . 
     As shown in  FIGS. 3   a  to  5   b , when the valve member comes to the closed position, the extending portion  60 - 2  of the valve member engages with the inner valve seat portion  42  to be elastically deformed with the outer annular sealing member  56  being pressed against the outer valve seat portion  38  ( FIGS. 4   a ,  4   b ). 
     The female coupling member  12  shown in the figures is provided with an O-ring  68  disposed on the side of the inlet with respect to the outer valve seat portion  38  of the inner peripheral surface of the coupling body  34  and the inner valve seat portion  42 . When the male coupling member  14  is inserted into to coupled to the female coupling member  12  and then the sealing engagement between the outer and inner annular sealing members  56 ,  60 , and respective the outer and inner valve seat portions  38 ,  42  is released, the O-ring sealingly engages with an outer peripheral surface of the male coupling member, thereby preventing a fluid from passing and then leaking outside through a gap between the inner peripheral surface of the female coupling member  12  and the outer peripheral surface of the male coupling member  14 . Further, the coupling body  34  is provided with a locking element  70  displaceable in the radial direction. The locking element engages with a locking element groove  72  formed on the outer peripheral surface of the male coupling member inserted into the female coupling member, whereby the male coupling member is secured to the female coupling member. In the figure, reference numeral  74  denotes a sleeve for pressing and releasing the locking element  70 , against and from the locking groove  72 . 
       FIGS. 3 to 5   b  show the movement of the valve member  44 , the outer and inner sealing members  56 ,  60  when the male coupling member  14  in the coupled state shown in  FIG. 2  has been pulled out of the female coupling member  12 . 
     When the valve member  44  comes close to the closed position, the cylindrical surface  54 - 2  of the outer peripheral surface and the first cylindrical surface  54 - 4  of the inner peripheral surface of the valve member  44  are advanced into the valve opening  40  first, and then the extending portion  60 - 2  of the inner annular sealing member  60  abuts against the inner valve seat portion  42 . When the valve member  44  is further advanced toward the closed position, the outer annular sealing member  56  is engaged with and pressed against the inclined surface  62  of the outer valve seat portion  38 , and at the same time, the extending portion  60 - 2  of the inner annular sealing member  60  is bent and elastically deformed so as to move away from the annular radially-extending surface of the valve member while engaging with the inner valve seat portion  42 . Thus, the sealing engagement between the outer annular sealing member  56  and the outer valve seat portion  38  is completed, and the sealing engagement between the inner annular sealing member  60  and the inner valve seat portion  42  is also completed ( FIGS. 4   a ,  4   b ). In this state, if a fluid pressure exists in the female coupling member  12 , the inner annular sealing member  60  is pressed by the fluid pressure and then brought into a state shown in  FIG. 5 , which provides more secure sealing. As noted from the drawings, when the valve member  44  is moved between the closed position and the open position, the outer annular sealing member  56  is moved without contact with the coupling body  34 . 
     The coupling member according to the present invention has been described above. However, the present invention is not necessarily limited to the above-described coupling member. For example, as shown in  FIG. 8 , the construction of the outer annular sealing member  56 ′ and the outer valve seat portion  38 ′ and the construction of the inner annular sealing member  60 ′ and the inner valve seat portion  42 ′ can be reversed compared with the above-described coupling member. Further, the construction of the inner annular sealing member  60  and the inner valve seat portion  42  in the above-described embodiment may be applied to the outer annular sealing member  56 ″ and the outer valve seat portion  38 ″, as shown in  FIG. 9 . In this case, it is necessary to stop the movement of the valve member, for example, by engaging the valve member itself with the outer or inner valve seat portion when the outer and inner annular sealing members are elastically deformed by a predetermined amount. Further, as shown in  FIG. 6 , the second cylindrical surface  54 - 6  may be extended to the side of the first radially-extending surface  54 - 5  to form a concave portion  76  along the outer periphery of the first radially-extending surface  54 - 5 , and the inner annular sealing member  60  may be provided with an annular protrusion which is fitted in the concave portion. This construction prevents glue applied to the second cylindrical surface  54 - 6  from flowing to the first radially-extending surface  54 - 5 . It is noted that glue is not necessarily used to fix the inner annular sealing member  60  to the valve member. For example, as shown in  FIG. 7 , an annular metal piece  80  having an L-shaped cross section may be used to fix the inner annular sealing member. Further, as shown in  FIG. 10 , the inner annular sealing member  60  and the outer annular sealing member  56  may be integrated into a single component.