Female pipe joint and pipe joint assembly

Abstract

[Problem] To provide a female pipe joint configured to prevent a seal member from being turned up and fallen off when inserting therein a corresponding male pipe joint. [Solution] A female pipe joint 10 is provided with a cylindrical joint body 16 having a passage 14, a seal member 18 disposed in the passage 14, a valve 20 disposed in the passage 14, and a spring 24 for biasing the valve 20 toward a closing position. The seal member 18 has a fitting projection 18a fitted to an annular recess 22 of the joint body 16, a front seal part 18b extending forward along the inner circumferential surface 16a of the joint body 16 from the fitting projection 18a, and a rear seal part 18c extending backward along the inner circumferential surface of the joint body from the fitting projection. When a corresponding male pipe joint 50 has been inserted into the passage 14, the front seal part 18b of the seal member 18 is sealingly engaged with the male pipe joint 50. The seal member 18 has a front-rear symmetrical shape.

Description

Female pipe fitting and pipe fitting assembly

[0001] The present invention relates to a female pipe fitting having a valve, and a pipe fitting assembly consisting of an interconnected female pipe fitting and a male pipe fitting.

[0002] Conventionally, there have been female pipe fittings (sockets) in which a flow path is closed by a valve (valve element) before connection, and when connected to a corresponding male pipe fitting (plug), the valve is placed in an open position to open the flow path. Such female pipe fittings include a fitting body that defines the flow path, a valve arranged to be movable back and forth within the passage, and a spring that biases the valve forward toward the closed position. The female pipe fitting also includes a seal member that forms a seal between the inner circumferential surface of the fitting body and the valve when the valve is in the closed position. When a corresponding male pipe fitting (plug) is inserted into the passage, the valve is pushed by the male pipe fitting to the open position, opening the flow path. The female pipe fitting also includes a seal member that forms a seal between the female pipe fitting and the male pipe fitting.

[0003] For example, in the pipe fitting disclosed in Patent Document 1, a seal member for sealing the gap with the valve and a seal member for sealing the gap with the male pipe fitting are formed by a single seal member (packing). This seal member has a body seal portion held in a stepped portion of the fitting body, a plug seal portion extending forward from the body seal portion and projecting radially inward, and a valve seal portion located at the connection position between the body seal portion and the plug seal portion. The body seal portion is provided on one end side of the seal member, and the plug seal portion is provided on the other end side.

[0004] Patent No. 4798510

[0005] When the allowable outer diameter of a female pipe fitting is small, the wall thickness of the fitting body must be thin to ensure the necessary flow path diameter, and the sealing member must also be thin. However, when a male pipe fitting is inserted, the thin sealing member is relatively easily deformed by the force of the male pipe fitting, and there is a risk that it will curl up from the inner circumferential surface of the female pipe fitting and become detached from the fitting body.

[0006] Therefore, an object of the present invention is to provide a female pipe fitting equipped with a sealing member that can solve the problems of the prior art, and a pipe fitting assembly consisting of such a female pipe fitting and a male pipe fitting that is connected to it.

[0007] That is, the present invention provides a female pipe fitting comprising: a cylindrical fitting body having an inner circumferential surface that defines a passage extending rearward from a front-end opening, and an annular recess formed on the inner circumferential surface; a seal member disposed within the passage and having a fitting projection that fits into the annular recess, a front seal portion extending forward from the fitting projection along the inner circumferential surface of the fitting body, and a rear seal portion extending rearward from the fitting projection along the inner circumferential surface of the fitting body; a valve disposed within the passage and displaceable between a closed position where it abuts against the rear seal portion of the seal member to close the passage, and an open position where it moves rearward from the rear seal portion to open the passage; and a biasing member that biases the valve towards the closed position, wherein when a corresponding male pipe fitting is inserted into the passage, the front seal portion of the seal member sealingly engages with the male pipe fitting.

[0008] In this female pipe fitting, when the front seal portion of the seal member receives a rearward force from the male pipe fitting, the rear seal portion is supported on the inner surface of the fitting body, making it possible to prevent the entire seal member from curling inward and becoming detached from the fitting body.

[0009] Furthermore, the front seal portion and the rear seal portion may be shaped symmetrically in the front-rear direction with the fitting projection as the center.

[0010] By making the seal member symmetrical in the front-to-rear direction, assembly work can be performed without having to worry about the orientation of the seal member during manufacturing.

[0011] The rear sealing portion of the sealing member may have a rearwardly facing flat sealing surface, the valve sealingly engaging the flat sealing surface in the closed position.

[0012] In addition, the front seal portion of the seal member can have a locking protrusion that protrudes radially inward, and the male pipe fitting can be inserted at least to the inside of the locking protrusion so as to sealingly engage with the locking protrusion.

[0013] Furthermore, the valve can have an extension portion that extends further forward than the locking protrusion of the sealing member in the closed position, and the extension portion has a pressing inclined surface that is inclined radially outward toward the front, so that when the valve is displaced from the closed position to the open position, the pressing inclined surface abuts against the locking protrusion, deforming the locking protrusion radially outward.

[0014] By using the inclined pressing surface to press the locking projection of the seal member, the locking projection can be gradually deformed before the male pipe fitting engages. This allows the front seal to be already pressed against the inner circumferential surface of the fitting body with a certain amount of force when the male pipe fitting contacts the locking projection of the seal member. This more reliably prevents the seal member from being turned up by the male pipe fitting when connected.

[0015] Furthermore, the present invention provides a pipe fitting assembly comprising the above-mentioned female pipe fitting and a male pipe fitting that is inserted into the passage of the female pipe fitting and connected to the female pipe fitting, wherein the extension portion of the valve has a front outer peripheral surface that extends forward from the pressing inclined surface, and the male pipe fitting has a sealing outer peripheral surface that sealingly engages with the locking protrusion of the seal member when inserted into the passage, and the diameter of the front outer peripheral surface of the valve is smaller than the diameter of the sealing outer peripheral surface of the male pipe fitting, and when the male pipe fitting is inserted into the passage and connected to the female pipe fitting, the valve is pressed by the male pipe fitting to move from the closed position to the open position, and the locking protrusion of the seal member is pressed radially outward by the pressing inclined surface and front outer peripheral surface of the valve and deformed, and is then further pressed radially outward by the sealing outer peripheral surface of the male pipe fitting and deformed.

[0016] By allowing the seal member to deform radially outward in stages due to the pressing inclined surface and front outer peripheral surface of the valve and the sealing outer peripheral surface of the male pipe fitting, the front seal portion of the seal member engages with the male pipe fitting while being pressed radially outward. Furthermore, when the male pipe fitting engages with the locking projection of the seal member, the force pushing the locking projection rearward is suppressed. This more reliably prevents the seal member from curling inward due to the male pipe fitting during connection.

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a female pipe joint and a pipe joint assembly according to the present invention will be described with reference to the accompanying drawings.

[0018] Fig. 4 is a cross-sectional view of a pipe joint assembly in a separated state according to an embodiment of the present invention; Fig. 5 is a first view showing a connection process of the pipe joint assembly of Fig. 1; Fig. 6 is a second view showing a connection process of the pipe joint assembly of Fig. 1; Fig. 7 is a cross-sectional view of the pipe joint assembly of Fig. 1 in a connected state; Fig. 8 is an enlarged view of the periphery of a seal member in a first state of the connection process of Fig. 2; Fig. 9 is an enlarged view of the periphery of a seal member in a second state of the connection process of Fig. 3; Fig. 10 is an enlarged view of the periphery of a seal member in a connected state of Fig. 4;

[0019] As shown in FIG. 1, a pipe joint assembly 1 according to one embodiment of the present invention comprises a female pipe joint 10 and a male pipe joint 50 which are detachably connected to each other.

[0020] The female pipe fitting 10 comprises a cylindrical fitting body 16 that defines a passage 14 extending rearward from the front end opening 12, a seal member 18 attached to the fitting body 16 within the passage 14, and a valve 20 disposed within the passage 14. The fitting body 16 is made up of a front body member 16-1 that defines a front portion of the passage 14, and a rear body member 16-2 that defines a rear portion of the passage 14. The front body member 16-1 and the rear body member 16-2 form an annular recess 22 on the inner circumferential surface 16a of the fitting body 16. The seal member 18 is attached to the fitting body 16 by fitting a fitting protrusion 18a that protrudes radially outward into the annular recess 22. The seal member 18 further has a front seal portion 18b extending forward from the fitting protrusion 18a along the inner circumferential surface 16a of the joint body 16, and a rear seal portion 18c extending rearward along the inner circumferential surface 16a. The seal member 18 seals between the front body member 16-1 and the rear body member 16-2 by the fitting protrusion 18a sealingly engaging with the front body member 16-1 and the rear body member 16-2, the rear seal portion 18c sealingly engaging with the rear body member 16-2, and the front seal portion 18b sealingly engaging with the front body member 16-1. The rear seal portion 18c has a flat seal surface 18d facing rearward. The front seal portion 18b also has a locking protrusion 18e with an arc-shaped cross section that protrudes radially inward. The joint body 16 may be formed as a single unitary member.

[0021] The valve 20 has a base portion 20b having a seal surface 20a that sealingly engages with the flat seal surface 18d of the seal member 18, and an extension portion 20c that extends forward from the base portion 20b. The extension portion 20c is formed with a pressing inclined surface 20d that is inclined radially outward toward the front, and a front outer peripheral surface 20e that extends forward from the pressing inclined surface 20d. The valve 20 is biased forward by a spring (biasing member) 24 to hold it in a closed position where the seal surface 20a sealingly engages with the flat seal surface 18d of the rear seal portion 18c of the seal member 18, closing the passage 14.

[0022] The female pipe fitting 10 further includes a spherical locking element 28 disposed in a locking element retaining hole 26 formed in the front body member 16-1 of the fitting body 16, and a sleeve 30 disposed so as to be movable in the front-rear direction on the outer peripheral surface 16b of the fitting body 16. The locking element 28 is supported from the inside by the front outer peripheral surface 20e of the valve 20 when it is in the closed position. The sleeve 30 is biased forward by a spring 32, but is supported from the inside by the valve 20 and is engaged with the locking element 28 when it is in the unlocked position, thereby holding it in the disconnected position.

[0023] 2, when a corresponding male pipe fitting 50 is inserted into the passage 14 of the female pipe fitting 10, the front end face 50a of the male pipe fitting 50 abuts against the valve 20, pushing the valve 20 rearward. The locking element 28, which was supported by the front outer peripheral surface 20e of the valve 20, is now supported by the outer peripheral surface 50b of the male pipe fitting 50.

[0024] As shown in FIG. 3, when the male pipe fitting 50 is further inserted into the passage 14, the valve 20 is pushed further rearward and the male pipe fitting 50 comes into contact with the locking projection 18e of the seal member 18.

[0025] As shown in FIG. 4 , when the male pipe fitting 50 is further inserted into the passage 14, the annular locking groove 50c formed on the outer peripheral surface 50b of the male pipe fitting 50 is positioned inside the locking element 28. The locking element 28 then moves radially inward into the annular locking groove 50c, engaging with the annular locking groove 50c and assuming the locked position. With the locking element 28 in the locked position, the spring 32 pushes the sleeve 30 forward and assumes the coupled position. The sleeve 30 in the coupled position supports the locking element 28 from the radially outward side with its inner peripheral surface 30a, maintaining the locking element 28 in the locked position. The tip of the male pipe fitting 50 is inserted to a position inside the locking projection 18e of the front seal portion 18b of the seal member 18, and the outer peripheral surface 50b of the male pipe fitting 50 is in sealing engagement with the locking projection 18e of the front seal portion 18b. The valve 20 is displaced to an open position where its seal surface 20a is separated rearward from the rear seal portion 18c of the seal member 18, opening the passage 14. The valve 20 has already opened the passage 14 in the state shown in FIG.

[0026] When connecting the female pipe fitting 10 to the male pipe fitting 50, the seal member 18 receives a rearward force from the valve 20 or the male pipe fitting 50. The seal member 18 of the female pipe fitting 10 has a front seal portion 18b and a rear seal portion 18c that extend forward and backward from the fitting protrusion 18a. Therefore, when the front seal portion 18b of the seal member 18 receives a rearward force from the valve 20 or the male pipe fitting 50, the rear seal portion 18c is supported by the inner circumferential surface 16a of the fitting body 16, preventing the entire seal member 18 from curling up and becoming detached from the fitting body 16. In particular, when the female pipe fitting 10 has a small diameter and the seal member 18 is accordingly small in diameter and thin in shape, the seal member 18 becomes less rigid and more likely to become detached. However, by employing the above-described configuration of the seal member 18, it is possible to effectively prevent the seal member 18 from becoming detached.

[0027] As can be seen from FIG. 5, the diameter D of the front outer peripheral surface 20e of the valve 20 is １ is the diameter D of the outer circumferential surface (sealing outer circumferential surface) 50b of the male pipe fitting 50 ２When connecting the male pipe fitting 50 to the female pipe fitting 10 as described above, the pressing inclined surface 20d of the valve 20 first abuts against the locking protrusion 18e of the seal member 18 (FIG. 5). The locking protrusion 18e is then pressed radially outward by the pressing inclined surface 20d of the valve 20, gradually deforming, and engages with the front outer peripheral surface 20e, before engaging with the male pipe fitting 50 (FIG. 6). The locking protrusion 18e is then pressed radially outward by the inclined chamfered portion 50d of the male pipe fitting 50, further deforming, and engages with the outer peripheral surface 50b of the male pipe fitting 50 (FIG. 7). When the locking projection 18e of the seal member 18 engages with the pressing inclined surface 20d and the front outer peripheral surface 20e of the valve 20, the locking projection 18e is not deformed very much, and therefore the rearward force that the locking projection 18e receives from the valve 20 is small. Furthermore, when the locking projection 18e engages with the male pipe fitting 50, the locking projection 18e has already been deformed radially outward to a certain extent, and therefore the rearward force that the locking projection 18e receives from the male pipe fitting 50 is smaller than when there is no deformation by the valve 20. Furthermore, when the male pipe fitting 50 engages with the locking projection 18e, the locking projection 18e is supported from the radially inner side by the front outer peripheral surface 20e of the valve 20, and therefore the front seal portion 18b is prevented from curling up inward even if the locking projection 18e receives a relatively large force from the male pipe fitting 50.

[0028] The seal member 18 has a shape that is symmetrical in the front-to-rear direction about the fitting protrusion 18a. Therefore, the seal member 18 can be properly installed even if the front-to-rear direction is reversed. In other words, if the seal member 18 is installed in the reversed front-to-rear direction, the portion designated as the rear seal portion 18c above becomes the front seal portion, and the portion designated as the front seal portion 18b becomes the rear seal portion. By adopting such a front-to-rear symmetrical shape, assembly work can be performed without having to worry about the orientation of the seal member 18 during manufacturing, thereby reducing the burden during manufacturing.

[0029] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, the seal member may not be symmetrical from front to back, and one of the rear seal portion and the front seal portion may be longer than the other. Note that terms indicating directions such as "forward" and "rearward" in the specification and claims are used for the purpose of clearly explaining the configuration of the invention and do not necessarily indicate directions in actual use.

[0030] 1 Pipe joint assembly 10 Female pipe joint 12 Front end opening 14 Passage 16 Joint body 16-1 Front body member 16-2 Rear body member 16a Inner peripheral surface 16b Outer peripheral surface 18 Seal member 18a Fitting protrusion 18b Front seal portion 18c Rear seal portion 18d Flat seal surface 18e Locking protrusion 20 Valve 20a Seal surface 20b Base portion 20c Extension portion 20d Pressing inclined surface 20e Front outer peripheral surface 22 Annular recess 24 Spring (biasing member) 26 Locking element holding hole 28 Locking element 30 Sleeve 30a Inner peripheral surface 32 Spring 50 Male pipe joint 50a Front end surface 50b Outer peripheral surface (sealed outer peripheral surface) 50c Annular locking groove 50d Chamfered portion

Claims

1. A female pipe fitting comprising: a cylindrical fitting body having an inner circumferential surface defining a passage extending rearward from a front-end opening, and an annular recess formed on the inner circumferential surface; a seal member disposed within the passage and having a mating projection that fits into the annular recess, a forward seal portion extending forward from the mating projection along the inner circumferential surface of the fitting body, and a rear seal portion extending rearward from the mating projection along the inner circumferential surface of the fitting body; a valve disposed within the passage and displaceable between a closed position in which it abuts the rear seal portion of the seal member to close the passage, and an open position in which it moves rearward from the rear seal portion to open the passage; and a biasing member that biases the valve toward the closed position, wherein when a corresponding male pipe fitting is inserted into the passage, the front seal portion of the seal member sealingly engages with the male pipe fitting.

2. A female pipe fitting as set forth in claim 1, wherein the front seal portion and the rear seal portion are shaped symmetrically in the front-to-rear direction with the fitting projection as the center.

3. A female pipe fitting as set forth in claim 1, wherein said rear sealing portion of said sealing member has a rearwardly facing flat sealing surface, said valve adapted to sealingly engage said flat sealing surface in said closed position.

4. A female pipe fitting as described in claim 1, wherein the front seal portion of the seal member has a locking projection that projects radially inward, and the male pipe fitting is inserted at least to the inside of the locking projection so as to sealingly engage with the locking projection.

5. A female pipe fitting as described in claim 4, wherein the valve has an extension portion that extends forward of the locking protrusion of the sealing member in the closed position, the extension portion has a pressing inclined surface that is inclined radially outward toward the front, and when the valve is displaced from the closed position to the open position, the pressing inclined surface abuts against the locking protrusion, deforming the locking protrusion radially outward.

6. A pipe fitting assembly comprising the female pipe fitting according to claim 5 and a male pipe fitting which is inserted into the passage of the female pipe fitting and connected to the female pipe fitting, wherein the extension of the valve has a front outer peripheral surface which extends forward from the pressing inclined surface, and the male pipe fitting has a sealing outer peripheral surface which sealingly engages with the locking protrusion of the sealing member when inserted into the passage, the diameter of the front outer peripheral surface of the valve is smaller than the diameter of the sealing outer peripheral surface of the male pipe fitting, and when the male pipe fitting is inserted into the passage and connected to the female pipe fitting, the valve is pressed by the male pipe fitting to move from the closed position to the open position, and the locking protrusion of the sealing member is pressed radially outward by the pressing inclined surface and front outer peripheral surface of the valve and deformed, and then is further pressed radially outward by the sealing outer peripheral surface of the male pipe fitting and deformed.

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