GB1584085A

GB1584085A - Coupling ring for use in snap-on fitting

Info

Publication number: GB1584085A
Application number: GB33753/77A
Authority: GB
Original assignee: Celanese Corp
Current assignee: Celanese Corp
Priority date: 1977-01-28
Filing date: 1977-08-11
Publication date: 1981-02-04

Description

(54) COUPLING RING FOR USE IN SNAP-ON FITTING (71) We, CELANESE CORPORA TION, a corporation organized and existing under the laws of the State of Delaware, located at 1211 Avenue of the Americas, New York, New York, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a coupling ring for use in a snap-on fitting. particularly a fitting for intercoupling fluid conveying con duits.

Couplings have heretofore been proposed for providing connections between fluid conveying conduits, as exemplified in U.S.

Patent Specifications Nos. 738.503, 2,831,711, 2,529.098, 3.532,367. Couplings such as these involve the use of a flow line having male and female connector elements. Connection between the male and female elements can be accomplished by a coupling ring. The coupling ring typically includes an annular base which salts within a channel formed in the male or female member, and an annular locking leg which extends outwardly at an angle from the base. During insertion of the male element into the female element. the locking leg is compressed and eventually springs outwardly into locking engagement with a iocking recess in the other element to prevent separation of the male and female elements.

An O-ring seal may be interposed between the elements to provide a fluid tight seal.

Snap-in couplings of this type can be quickly and easily assembled without the need for tools. The present invention contemplates the use of this type of coupling in a fitting for vehicle brake systems to obtain a dependably secure connection with a coupling ring sufficiently flcxible to facilitate axial convergence of the male and female elements.

The present invention also envisions in one preferred aspect a coupling of this type which can be easily disassembled without completely removing the female connector element from its associated fluid conduit.

It is a general object of the present invention to provide a tube fitting for vehicle air brake systems.

It is a further object of the present invention to provide a snap-in coupling which is easily assembled to provide a reliably stropg connection.

It is another object of the invention to provide a coupling ring for use in a snap-in coupling joint which facilitates the initial coupling action while being highly resistant toward uncoupling forces.

It is a further object of the invention to provide a snap-in coupling which may be easily disassembled without requiring complete removal of the female element from its associated fluid conveying conduit.

According to the present invention there is provided a coupling ring for use in a snap-in fitting of the type including male and female connector elements. one of said connector elements including an annular retaining channel and the other of said connector elements including a locking groove: the coupling ring comprising: an annular base portion including an annular first wall. an annular second wall spaced radially from said first wall. and an annular radial end wall interconnecting adjacent ends of the first and second walls: an annular collar portion ingegral with the base portion and extending from a side of the base portion opposite the radial end wall.

the collar portion including an annular first wall and an annular second wall spaced radially therefrom: the second wall of said collar portion being continuous with the second wall of the base portion and defining a seating surface adapted to seat in the retaining channel: the first wall of the collar portion being spaced radially from the plane of the first wall of said base portion and converging toward said seating surface in a direction away from said base portion; the coupling ring further comprising an annular locking portion integral with the base portion and extending from a side thereof opposite the radial end wall of the base portion, said locking portion being of longer length than said collar portion and including; an annular first wall. an annular second wall spaced radially therefrom, and an annular radial terminal wall interconnecting said second and first walls of said locking portion; the second wall of the locking portion extending from the base portion toward the terminal wall at an acute angle relative to said first wall of the collar portion to form a vertex therewith, the terminal wall adapted to seat within the locking groove; the first wall.of the locking portion being continuous with. and extending at an angle from, the first wall of the base portion and being divergent relative to said second wall of the locking portion in a direction away from said base portion; the vertex being disposed closcr to the end wall of the base portion than is the place of intersection of said first walls of the base and locking portions; and the locking portion including a plurality of circumferentially spaced resiliency slots extending therethrough. one of said slots extending completely through the ring to facilitate mounting thereof on the element carrying the retaining groove.

Preferably. the coupling ring of the invention is one wherein the first wall of the base portion is an axially extending outer wall.

the second wall of the base portion is an axially extending inner wall spaced radially inwardly from the outer wall. the first wall of the collar portion is a gencrally frustoconical outer wall. the second wall of the collar portion is an axially extending inner wall.

the first wall of the locking portion is a generally frustoconical outer wall and the second wall of the locking portion is a generally frustoconical inner wall.

The invention also includes a snap-in fitting comprising a male connector element having an annular retaining channel. a female connector element having a locking groove; and a coupling ring as defined above. the coupling ring bering adapted to seat in the retaining channcl and locking groove. therebv coupling the male connector to the female connector.

The female connector element may be of one Unitary piece or it may comprise an adapter portion and a retaining sleeve por tion detachably secured thereto. l Uhe adap- ter portion includes a first socket portion having a first circumferentia Ily extending groove portion. The retaining sleeve portion includes a second socket portion which is aligned with the first socket portion and which has a second groove portion aligned with the first groove portion to define the locking groove for receiving the locking portion. The retaining sleeve portion and the adaptor portion are separable to disassemble the fitting and expose the coupling ring.

Other objects and advantages of the present invention will become apparent from the subsequent detailed description of a preferred form thereof in connection with the accompanying drawings in which like numerals designate like elements and in which: Figure 1 is a front view of a coupling ring, in its free state, according to the present invention; Figure 2 is a cross-sectional view of the coupling ring taken along line 2-2 of Figure 1; Figure 3 is a side elevational view of the coupling ring disposed within a snap-in fitting according to the present invention with a portion of the fitting being broken away in longitudinal section; Figure 4 is a side elevational view of another form of snap-in fitting according to the invention. with a portion of the fitting being broken away in longitudinal section.

Figure 5 is a schematic. exploded view of an L-shaped fitting employing a one-piece socket in accordance with Figures 1 to 3; Figure 6'is a schematic. exploded view of an L-shaped fitting for overcoming a specific shortcoming of the Figure 5 arrangement; and Figure 7 is a schematic. exploded view of an L-shaped fitting employing a two-piece socket and which overcomes problems associated with the fittings of both Figure 5 and Figure 6.

A preferred snap-in fitting l() according to the present invention is depicted in Figure 3 and includes a female connector element 12 and a male connector element 14. The illustrated female connector element 12 includes an enlarged socket 2(). Projecting from the female connector 12 and preferably molded integrallv therewith-is an additional male connector 17. 'These two connector elements 12 and 17 can be molded in one piece of a thermoplastic material. preferably nylon. although other materials are equally suitable.

The axially extending. outwardly open socket 20 is defined bv an internal wall 18 of the female connector 12. which wall termin ates in an outwardly flared edge 22. The illustrated male connector 17 projecting from the base of the female connector 12 and axially aligned with the socket 12 comprises in externally threaded nipple 19.

This nipple I 19 is adapted for terminal connection to a fluid conduit. such as the air inlet of a vehicle air brake mechanism. A through-passage 24 is formed in the nipple 19 to communicate with the socket 20.

It will be appreciated that in some inst ances th'e additional male connector 17 associated with the female connector 12 may instead be a member essentially identical to the illustrated male connector 14 that mates with the female connector 12. In such cases the passage through the additional male connector 17 will ordinarily be oriented at an angle (e.g., 90 ) to the axis of the socket 20 and a suitable transition passage will connect the two. The additional male con nector 17, when it takes the form of the illustrated maletconnector 14, could in turn be mated to a socket such as the one shown at 20 which is integral with an aligned nipple such as the one shown at 19. ln this fashion, suitable flexibility, for example, for 90" turns is provided at a terminal connection.

It will also be appreciated that the present invention contemplates in-line couplings of tubes and the like to one another, as well as terminal connections. In such instances a double ended female member having sock ets 20 facing outwardly at both ends may be employed. Each such socket 20 will mate with the basic male connector 14 as discus sed more fully below.

A radially inwardly open. annular locking groove 26 is formed in the socket wall 18.

This locking groove 26 extends circumferen tially around the wall 18 and has a generally radial abutment wall or should 28 located at an outer end of the groove. i.e.. at an end of the groove nearest the open end of the socket. The locking groove 26 may be machined in the molded female connector 12 and the shoulder 28 may be circumferentially continuous. However. the groove 26 may be molded in place. in which event.

circumferentially spaced and longitudinally extending tobl access and removal slots (as illustrated in phantom at 27) would be provided by a compatibly configured. col lapsible or retractable multipiece molding core (not shown). The slots would. of course, be separated bv lands so that a discontinuous should 28 would be present at the outer end of the locking eroove 26.

The male connector element 14 comprises a tubular spigot portion 32. Associated therewith is an oppositely facing'. socketed section 30. These two members 3() and 32 are preferablv of one-piece construction.

and can be molded of the same material as the female co'nnector 12 and its associated inale connector 17. The socket 3() can be suitably coupled. as by welding or other bonding technique. to a conduit such as a nylon air hose dr tube (schematically shown at 36) used in a vehicle air brake system.

The spigot 32 illclutt s a passage 34 which communicates with the socket 3() and is in general axial alignment with the socket 20 of the female connector 12 when the connectors 12, 14 have been merged.

An annular, circumferentially arranged retaining channel 40, which is radially outwardly open, is provided on the outer wall of the spigot 32. When the male and female connectors 14 and 12 have been merged, the retaining channel 40 is disposed in oppositely facing relation to the locking groove 26.

The retaining channel 40 includes a radially extending, axially facing side wall 42 which is located axially inwardly of the abutement wall 28. i.e.. toward the internal end of the socket 20. The channel 40 also includes a stepped bottom wall preferably formed by radially stepped inner and outer surfaces 46.

48, respectively.

A coupling ring 60 is insertable within the retaining channel 40 to connect the male and female elements together. The coupling ring is preferably formed of a relatively stiff material so as to maximize the strength of the connection afforded therebv. The relative stiffness of this material employed to provide an adequately strong couplirig. renders it somewhat resistant to the compressive action which must occur during merging of the male and female elements. The coupling ring 60 has. however. been made sufficiently flexible and resilient to facilitate initial connection of the elements, without impairing the reliability of the connection, as will now be discussed.

In its preferred form the coupling ring 60 includes an annular base portion 62, an annular collar portion 64. and an annular locking portion 66. The coupling ring 60 is of one-piece construction. so that the base.

collar and locking portions 62, 64, 66 are integral. For example. when utilized in a critical area where a high degree of reliabil ity is required. the ring can be molded of a relatively stiff nylon such as nylon 11 or of other thermoplastic materials whose stiffness is sufficient to provide a strong, reliable connection while being sufficiently resilient to accommodate the coupling action described below. It is also envisioned that some metals. for example spring steel.

stainless steel or brass. may provide these characteristics.

Preferably when the ring 60 is constructed of thermoplastic material (which may. if desired. be reinforced in some instances with materials such as fiber glass fillings) and employed in a fittting for air brake tubes or other severe pressure applications, the material of the ring has a flexure modulus at about room temperature in the range of 0.7 x 1()D psi to 8 x l(l5 psi as determined bv ASTM test D-79(). and a compressive strength at about room temperature of between 2.0()() psi to 22.000 psi as determined by ASTM test D-695. A variety of appropriately dimensioned thermoplastics such as polyethylene, PVC, CPVC, polypropylene and polystyrene materials, as well as the aforementioned nylon materials.

are contemplated in this regard. When the ring is constructed of thermoplastic material and employed in less severe pressure applications such as in fittings for instrumentation systems, the lower end of the aforemen- tioned flexure modulus range may be 0.8 x 1()t psi.

The base portion 62 of the ring 60 includes an annular, axially extending outer wall 68, an annular. axially extending inner wall 70 spaced radially inwardly therefrom, and an annular radial wall 72 which interconnects adjacent ends of the outer and inner walls 68. 70. When the elements 12, 14 are interjoined, the radial wall 72 abuts against the side wall 42 of the retaining channel 4(), as depicted in Figure 3.

The collar portion 64 extends from a side of the base portion 62 which is opposite the end wall 72 and extends in a direction generally parallel to the axis of the coupling assembly. This collar 64 includes an annular axially extending 'inner wall 74 and an annular outer wall 76 spaced radiallv therefrom. The inner wall 74 of the collar portion 64 defines a cylindrical seating surface which seats snugly within the retaining channel 4().

A snug fit is assured since the diameter of the inner surface 74. in its free state. is slightly smaller than that of portion 46 of the retaining channel 4(). The inner wall 74 of the collar portion 62 is contiguous with the inner surface 70 of the base portion 62.

Moreover. these inner surfaces are preferably aligned. in which case the inner surface 70 of the base portion 62 forms part of the seating surface.

The outer wall 76 of the collar portion 64 is disposed radially inwardly of the plane of the outer wall 68 of the base portion 62. This outer wall 76 of the collar portion is generally frustoconical so as to converge toward the inner wall 74 in a direction away from the base portion 62.

The locking portion 66 extends from a side of the base portion 62 opposite the end wall 72. i.e.. from the same side as the collar portion 64. The length of the locking portion 66 is greater than that of the collar portion 64. The locking portion 66 includes an annular generally frustoconical inner wall 82. an annular generally frustoconical outer wall X4 and an annular. radial terminal wall '8'6 which interconnects adjacent ends of the inner and outer walls 82. 84.

The inneiwall X2 of the locking portion 66 extends from the base portion t0\\'11d the terminal wall K6 it an 'cute angle relative to the outer wall 76 of the collie portion 64 to foim a vertex V therewith.

The terminal wall X6 of the locking portion 66 is disposed radially outwardly of the plane of the outer wall 68 of the base portion 62 in the uncompressed state of the ring 60.

When the elements 12, 14 have been merged, the terminal wall 86 lockingly abuts against the abutment wall 28 of the locking groove 26 to resist axial detachment of the male and female elements, as depicted in Figure 3.

The outer wall 84 of the locking portion 66 is contiguous with. and extends at an angle from. the outer wall 68 of the base portion 66. This outer wall 84 diverges relative to the inner wall X2 in a direction away from the base portion 22. Thus. the thickness of the locking portion 66 is smallest at the place where it joins the base portion 62, and is largest at the place where it abuts against the locking groove 26, for reasons to be discussed.

The distance d from the end wall 72 of the base portion 62 to the vertex V is less than the distance d from the end wall 72 to the place P where the outer walls X4. 68 intersect. Thus. the place of intersection P terminates beyond the vertex V considered in a direction away from the end wall 72.

In order to render the locking portion 66 of sufficient resiliencv to compress radially during mating of the elements 12, 14. the locking portion 66 is provided with a plural itv of circumferentially spaced resiliency slots 90. As can be viewed in Figures I and 2. the slots 9()A. B extend completely through the locking portion 6X and partially through the base portion 60. i.e.. through the radially outer half of the latter. Any number of such slots 9() may be provided, although three such slots are preferred.

spaced 1200 apart. One slot ')()C' of these slots extends completely through the cou pling ring. that is. completely through the base. collar and locking portions 62. 64. 66.

The coupling ring 6() is thus split to facilitate insertion onto the male element 14.

Disposed within the spigot 32 forwardly of the retaining groove 4() is an annular circumferential recess l()() which is radially outwardly open. This recess l()() carries an annular sealing ring l()2. preferably in the form of an elastomeric O-ring. When the male and female connector elements 14. 12 are interjoined. the 0ring 1(X2 is compress ively engaged with the socket wall it to provide a fluid seal.

A first step in interjoinine the male and female elements 12. 14 involves inserting the coupling ring 6() onto the spigot portion 32 of the male member 14 bv separating the ring portions in the vicinitv of the slot C)OC.

The ring 6(1 is inserted into the retaining channel 4(1 such that the seating surface is snugly seated upon the wall portion 46 of the retaining channel 4().

The spigot 32 of the male element 14 and the socket 2() of the female element 12 are then merged axially so that the locking portion 66 engages the flared edge 22 of the socket portion and is pivoted radially inT wardly about the region P. During continued merging of the connector elements 12, 14, the locking portion 66 is held in a compressed state against the outer wall 76 of the collar portion 64 as a result of contact with the socket wall 18. When the elements 12, 14 have been merged sufficiently so that the terminal wall 46 of the locking portion passes the abutment wall 28 of the locking groove. the locking portion 66 swings outwardly about the region P and into the locking groove 26. In this condition. detachment of the male and female elements is restrained by the physical abutment between the terminal wall 86 of the coupling ring 60 and the abutment wall 28 of the locking groove 26.

This coupling operation is greatly facilitated by certain features of the coupling ring. For example, since the cross-sectional thickness of the locking portion 66 is smallest at region P, it is assured that. despite the relative stiffness of the ring 6(). inward pivoting of the locking portion 66 will occur at about the region P, rather than at a point closer to the terminal wall 86. Accordingly.

subsequent outward pivoting of the locking portion into the locking groove will also occur about the region P, guaranteeing maximum radial entry of the terminal wall 86 into the locking groove 26.

Moreover, the vertex V, in being disposed closer to the end wall 72 than the region P, forms an undercut of the region P which further tends to locate the pivot zone of the locking portion 66 closelv adjacent the base portion 62.

These factors thus serve to maximize the pivot arc of the locking portion 66 and assure that substantially the entire length and cross section of the locking portion will be available to resist forces tending to uncouple the connector elements 12. 14.

Also. the reduced thickness of the locking portion at the region P makes it possible to compress the -locking member with less effort. thereby making it considerably easier to merge the elements 12. 14.

The converging relationship of the upper wall 76 of the collar portion 64 relative to the inner surface 74 assures that ample qrea between the surfaces 76. 82 of the collar and locking portions will be available to receive the compressed locking portion 66 during a merging operation. Thus. there. is little danger of the ring 6() becoming jammcd in the socket short of its locking position.

In a second preferred embodiment of the invention, illustrated in Figure 4. the female connector element 12A compriscs a retaining sleeve portion 13A and an adaptor portion 15A. The adaptor portion 15A includes a male connector 17A comprising a threaded nipple 19A and a through-passage 24A.

Connection of the retaining sleeve 13A to the adaptor 15A is effected by threading merging internal threading 16A on the retaining sleeve 13A with external threading 21A on the adaptor 15A.

The retaining sleeve 13A and the adaptor 15A together define a socket 2()A for receiving the male connector element 14.

The socket wall is formed by axially aligned bores 184, 18B in the retaining sleeve 13A and the adaptor 15A, respectively. The bore 18A terminates in a flared edge 22A.

The retaining sleeve 13A and the adaptor 15A include aligned circumferential grooves 26A, 26B, respectively, which cooperate to form a locking groove for receipt of the annular locking portion 66 of the coupling ring 60. The groove 26A of the retaining sleeve 13A includes a radial abutment shoulder 28A located at an outer end thereof.

The dimension of the retaining sleeve from the abutment shoulder 28A to an inner end 31A is sized so that when the end 31A contacts a stop surface 33A of the adaptor 15A. the shoulder 28A is situated substantially at a location coinciding with the outer end 86 of the locking arm 66 of the coupling ring.

It will be appreciated that the retaining sleeve 13A and the adapter 15A together form structure which is similar in arrangement and function to that described in conjunction with the first preferred embodiment in that a socket 20A in the female connector element 12A receives the spigot 32 of the male element 14. so that the locking portion 66 of the coupling ring 60 is initially compressed by contact with the flared edge 22A and then swings outwardly into the locking groove 26A, 26B. Physical abutment between the terminal wall 86 of the coupling ring and the abutment wall 28A of the locking groove portion 26A prevents detachment between the male and female elements 14. l2A.

An added feature is provided by the threaded arrangement of the portions 13A.

15A of the female element 12A in that the retaining sleeve 13A can be separated from the adaptor ISA. enabling disassembly of the connection without removing the adapter ISA from the fluid conduit to which the nipple l9A is connected. In addition. separation of the retaining sleeve 13A from the adaptor ISA, exposes the coupling 60 for simplified removal of the retaining sleeve 13A.

The retaining sleeve 13A is easilv detached from the adapter 15A since it is capable of rotation relative to the male element 12, the coupling ring 60. and the adapter ISA.

Anothel advantage of the two-piece female connector element 12A is provided in conjunction with a connector of the type discussed earlicr in which the through passage comprises right angle sections, i.e., an L-shaped passage.

In this regard. reference may be had to Figures 5 to 7. Briefly, Figure 5 depicts an L-shaped fitting which employs a one-piece integral socket portion of the type described earlier in connection with Figures 1 to 3; Figures 6 depicts an arrangement capable of overcoming a disadvantage of the Figure 5 structure although involving certain disadvantages

Claims

**WARNING** start of CLMS field may overlap end of DESC **. capable of rotation relative to the male element 12, the coupling ring 60. and the adapter ISA. Anothel advantage of the two-piece female connector element 12A is provided in conjunction with a connector of the type discussed earlicr in which the through passage comprises right angle sections, i.e., an L-shaped passage. In this regard. reference may be had to Figures 5 to 7. Briefly, Figure 5 depicts an L-shaped fitting which employs a one-piece integral socket portion of the type described earlier in connection with Figures 1 to 3; Figures 6 depicts an arrangement capable of overcoming a disadvantage of the Figure 5 structure although involving certain disadvantages of its own; and Figure 7 depicts a fitting which may be employed in lieu of the Figure 6 fitting to provide the latter s advantages and eliminate its disadvantages. In Figure'S an L-shaped fitting is illustrated which employs a female connector element 12C. This female connector element 12C includes a one-piece integral socket portion 2()C and a male connector 17C in the form of a thlcacled nipple 1 9C oriented at a right angle relative to one another. A 9() degree. or L-shaped. through passige 24t extends from one end of the connector element 12C to the other. The nipple 1 9C is adapted to be secured to a fluid conduit. such as in air inlet F of a vehicle aii brake mechanism. The male connector element 14 is securable to the female connector element 12C by a coupling ring 6() in the manner discussed in connection with the embodiment of Figures 1 to 3. Since such connection is permanent. however. it is not possible to conveniently remove the nipple 1 9C from the air inlet F. That is. no appreciable rotation of the female connector element 12C is possible when the male connector element 14 and its conduit (not shown) are connected to the female connector element 12C. One arrangement which has been llCCIl prop- osed in an effort to overcome this shortcom- ing is depicted in Figure 6. In this irrange- ment a female connector element 1 2L) is provided with a male spigot portion 321) which is similar to that of the mile connec- tor element 14 in that it receives a coupling ring 6() of a female connector element 12. The latter is connected to the air inlet F and can be easily unscrewed therefrom since the coupling ring 6(1 permits relative rotation between the female connector elements 12 and l2D. A disadvantage with this irrinee- ment is the need for employing additioiiil parts and the increase in over-ail size of the fitting. These disidvantages can be overcome utilizing a female connector element which incorporates a feature similir to the twopiece socket arrangement 13A, 15A discussed earlier in connection with Figure 4. In this connection, attention is directed to Figure 7 in which an L-shaped female connector element 12CA is utilized. This connector element 12A includes an adapter portion 15CA and a removable retaining sleeve 13CA threadedly mountable thereon. The sleeve 13CA and adapter 15CA cooperate .to form a socket 2()CA and a locking groove 40CA. A 90 degree through passage 24CA extends through the female element 12CA and communicates with the air inlet F when the element 12CA is connected thereto. A male connector element 14, with its conduit. can be securable within the socket 20CA to complete the connection. Removal of the fitting from the air inlet F can be accomplished by first unscrewing the sleeve 13CA and extracting the male connector element 14 from the socket 20CA. The female connector element 13CA is thus able to be unscrewed from the air inlet F. absent the need for the extra components required by the Figure 6 structure. WHAT WE CLAIM IS:

1. A coupling ring for use in a snap-in fitting of the type including male and female connector elements. one of said connector elements including an annular retaining channel and the other of said connector elements including a locking groove; the coupling ring comprising: an annular base portion including an annular first wall. an annular second wall spaced radiallv from said first wall. and an annular radial end wall interconnecting adjacent ends of the first and second walls: an annular collar portion integral with the base portion and extending from a side of the base portion opposite the radial end wall. the collar portion including an annular first wall and an annular second wall spaced radially therefrom: the second wall of said collar portion being continuous with the second wall of the base portion and defining a seating surface adapted to seat in the retain lag channel: the first wall of the collar portion being spaced radially from the plane of the first wall of said base portion and converging toward said seating surface in a direction awav from said base portion: the coupling ring further comprising an annular locking portion integral with the base portion and extending from a side thereof opposite the radial end wall of the base portion. said locking portion being of longer length than said collar portion and includ ing: an annular first wall. an annular second wall spaced radially therefrom. and an annular radial terminal wall interconnecting said second and first walls of said locking portion: the second will of the locking portion extending from the base portion toward the terminal will at an acute angle

relative to said first wall of the collar portion to form a vertex therewith, the terminal wall adapted to seat within the locking groove; the first wall of the locking portion being continuous with, and extending at an angle from, the first wall of the base portion and being divergent relative to said second wall of the locking portion in a direction away from said base portion; the vertex being disposed closer to the end wall of the base portion than is the place of intersection of said first walls of the base and locking portions; and the locking portion including a plurality of circumferentially spaced resiliency slots extending therethrough. one of said slots extending completely through the ring to facilitate mounting thereof on the element carrying the retaining groove.

2. A coupling ring according to claim 1 wherein the first wall of the base portion is an axially extending outer wall, the second wall of the base portion is an axially extending inner wall spaced radially inward ly from the outer wall, the first wåll of the collar portion is a generally frustoconical outer wall, the second wall of the collar portion is an axially extending inner wall, the first wall of the locking portion is a generally frustoconical outer wall and the second wall of the locking portion is a generally frustoconical inner wall.

3. A snap-in fitting comprising a nlale connector element having an annular retaining channel, a- female connector element having a locking groove. and a coupling ring as defined in claim I or 2. the coupling ring being adapted to seat in the retaining channel and locking groove. thereby coil- pling the male connector to the female connector.

4. A snap-in fitting according to claim 3 wherein the base and collar portion of the coupling ring define an annular seating surface of smaller diameter than the dia- meter of the retaining channel. prior to assembly of the coupling ring.

5. A snap-in fitting according to claim 3 or 4 wherein the female connector element includes an axially extending. outwardly open socket. which socket has an annular- socket-defining wall terminiting in an outwardly flirted edge at the axially open end of said socket. the socket-defining wall includ- ing an annular locking groove extending circumferentially therearound. said groove including a generally radial abutment will it an outer groove end. and the male connect tor element includes an annular. ciicui9- ferentiallv arranged. radially outwardly open retaining channel disposed in oppo- sitelv facing relation to the locking groove.

when the male and female connector clc- ments are interjoined. the retaining cllnnncl including a bottom will and a 1 radial side wall. the side wall located axially inwirdly of the abutment wall of said locking groove, and an annular, circumferentially arranged.

radially outwardly open recess situated for wardly of the retaining channel.

6. A fitting according to claim 5 including an additional connector projecting from the female connector element away from the socket, an additional socket projecting from the male connector element away from the female connector element. and a tube coupled to the additional socket.

7. A fitting according to claim 5 or 6 wherein the retaining channel is radially stepped. the collar portion being mounted in a radially inner portion of the channel and the locking portion being received in a radially outer portion of the channel during coupling of said male and female elements.

X. A fitting according to claim 5 wherein the female connector element includes an adapter portion and a retaining sleeve portion threadedly securable together, the adaptor portion and the retaining portion each including means cooperating to define the socket and the annular locking groove.

9. A fitting according to claim 8 wherein the female connector element is of L-shaped configuration and includes a connector portion disposed opposite the socket and cxtending sulistantiallv ')() degrees relative thereto. the connector portion being rotatably connectable to, and detachable from. a fluid conducting structure.

10. A snap-in fitting of the type in which a male connector element is securable within a socketed female connector element, the male connector element carrying a coupling ring according to claim I or dlim 2 engage- able with a groove in the female socket upon merging of the male connector element into said socket. to prevent separation of the male and female connector elements.

wherein the female connector element comprises: an adapter portion comprising: a first connector end adapted for connection with a fluid conductor. and a second end includ- ing a first socket portion. said first socket portion including a first circumferentially extending groove portion: a retaining sleeve portion including q second socket portion: said second socket portion being aligned with said first socket portion to form therewith said socket for receiving said male connector. and including a second groove portion suh'tintiilly aligned with said first groove portion to define said groove for receiving the allllula locking portion of said coupling ring. said second groove portion including a generallv radial abutment sur- face engageable with the annular radial terminal wall of said locking portion to resist disassembly of the fitting: and means for releasibly securing said retaining sleeve portion and said adapter portion together.

said portions being separable to disassemble said fitting and to cxpose said coupling ring

11. A fitting according to claim 10 wherein the retaining sleeve includes a flared edge at an end thereof opposite said internal threading, to facilitate entry of the male connector clement into said socket.

12. A fitting according to claim 10 or claim II wherein the retaining sleeve includes in inner end which abuts against a stop surface of the adapter; the dimension of the retaining sleeve from the abutment shoulder to said inner end being sized so that with said inner end in contact with said stop surface, said abutment should. substan- tially coincides with said annular radial terminal will of said locking portion.

13. Apparatus according to any one of claims 10 to 12 wherein the releasable securing means comprises external threading on the adaptor portion and internal threading on the rctaining sleeve portion.

14. Appiratus according to any one of claims I() to 13 wherein the female connector element is of L-shaped configuration and includes a connector portion disposcd opposite said socket and extending substantially 9() degrees relative thereto: the connector portion being rotatably connectable to. and detachable from. a fluid conducting structure.

15. A coupling ring for use in snip-in fittings. substantially as hereinbefore described with reference to and is illustrated in the accompanying drawings.

16. A snap-in fitting substantially as hereinbefore described with reference to and as illustrated in Figure 3, 4. 5. 6. or 7 of the accompanying drawings.