QUICK CONNECT COUPLING

Abstract: A quick connect female coupling with a biasing means (30) in a bore of the coupling that bias an O-ring (24) type packing in sealing engagement against part of the coupling and a pipe end portion when the coupling is in use. A retaining ring (36) in the coupling snap fits against an external collar (14) of a pipe end portion as a retaining means when the coupling is in use.

Description: The invention relates to pipe joints or couplings, but more particularly the invention relates to a snap fit connecting coupling with an O-ring type packing. Quick connect couplings are supplanting other types of fluid couplings such as flared, beaded, and tapered fittings coupled together with a swivel type nut; or hoses that are coupled to a pipe end portion with an external hose clamp. Quick connect couplings are being used in many applications, such as automotive applications, because of a minimum amount of time they require to make a connection and effect a fluid seal. Such couplings may have an O-ring type packing disposed in the bore of a housing as a means for effecting a seal between the housing and a male end pipe portion; a snap fit connection may be used for quickly connecting the housing to a male end pipe portion. Examples of quick connecting couplings using at least one O-ring between a male end pipe portion and a housing member appear in US-A-4 423 892, US-A-4 541 658 (& GB-A-2 166 509), EP-A-193 271 and EP-A-168 223. In such couplings, the O-rings effect a fluid pressure augmented seal along (1) a circumferential length at the O.D. of a male end pipe portion and (2) along a circumferential length at an I.D. portion of a housing (i.e., along I.D. and O. D. portions of the O-ring, respectively). In some applications, redundant O-rings with back-up rings are used because the fluid pressure activated seals are required to effect sealing along the cumulative length at the O.D. of a pipe end portion and the O.D. of a housing portion; redundant O-rings have proven effective when there is relative motion between a coupling housing and an attached pipe end portion. EP-A-193 271 discloses male and female couplings for a push-in conduit connection. Resilient fingers in a metal retainer are used to maintain the male end portion in position. Couplings such as disclosed in EP-A-193 271 and in US-A-4 541 658 thus require elaborately shaped, snap fit retaining means for interfitting with a coupling housing and a male end pipe portion being retained. Various objects of the invention are: to eliminate the requirement of fluid pressure for enhancing a fluid tight seal between a pipe end portion and a coupling housing; to minimise the cumulative length of a seal that must be affected (i.e., the cumulative length along the I.D. and O.D. of an O-ring type packing); to effect a fluid tight seal while compensating for O-ring distortion and aging; and to simplify the snap fit connecting means for retaining a pipe end portion which has an external collar. According to the invention, there is provided a female coupling with a housing having at least two substantially coaxial bores for receiving a male end pipe portion having a collar, one bore being of larger diameter than the other bore so that the housing has an annular shoulder at the junction between the bores; at least one O-ring in the housing to define a sealing means for the housing and said male end pipe portion with the collar; and a retaining means for retaining part of the inserted male end pipe portion with the collar, the retaining means having deflectable fingers; characterised in that: the larger diameter bore of the housing is sized to receive the O-ring without radial clearance; a spring bias means in the housing biases the O-ring against a portion of the annular shoulder, thereby deforming the O-ring to effect a seal with the shoulder, and the opposite end of which is axially displacable by said collar by an amount at least equal to the desired collar thickness to permit insertion of said male end pipe portion; and the deflectable fingers are juxtaposed the displaceable end of the spring bias means, and are deflectable an amount at least equal to the desired collar height to accommodate said collar, and act as a means for engaging said collar to effect retention of the inserted male end pipe portion. The invention is now described by way of example with reference to the accompanying drawing, in which:- FIG. 1 is an exploded isometric view showing component parts associated with one embodiment of a quick connect coupling of the invention; FIG. 2 is a front view in partial axial section showing the assembled component parts of FIG. 1; FIG. 3 is a front view of a prior art male end pipe portion of the type with an external collar; FIG. 4 is a view similar to FIGS. 2 and 3 but showing the coupling of the invention attached to the male end pipe portion, and FIG. 4 also shows another embodiment of the invention utilizing two O-rings; FIG. 5 is an enlarged partial view taken along the line 5-5 of FIG. 4 but showing the use of only one O-ring as in the coupling of FIG. 2; FIG. 6 is a view taken along the line 6-6 of FIG. 2 showing an optional deformation of a portion of the coupling; and FIG. 7 is a view similar to FIG. 2 but showing another embodiment of the invention. Description of Preferred Embodiment Referring to the Figures, a female coupling 10 is provided which is of the type for quickly connecting to a male end pipe portion 12 which has an external collar 14 and a bull-nosed type end 16. The coupling has a housing 18 in which there are at least two essential and substantially coaxial bores adapted for receiving a male end pipe portion. A first bore 20 is sized slightly larger than the pipe end portion to be received and a second bore 22, larger than the first bore 20, is sized to receive an O-ring 24, that is oriented coaxially with the bores. The difference in bore diameters define an intermediate, generally radially extending annular shoulder 26 against which a side portion 28 of the O-ring is located. A biasing means, such as in the form of a coiled compression spring 30, is located in and oriented substantially coaxially with the larger diameter bore, has a first end 32 juxtaposed a side portion of the O-ring that oppositely faces the annular shoulder 26. Optionally, but preferably, a back-up ring 34 is interpositioned between the O-ring and the end 32 of the spring. The spring presses the O-ring in sealing engagement against the shoulder 26 which is later explained. A means for retaining a part of a pipe end portion is disposed in the housing and is in the form of a retaining ring 36 which has a plurality of deflectable fingers 38 that extend radially inwardly into at least part of the larger diameter bore 22. The retaining ring 36 may optionally be split at 40 so that the ring may be deformed and removed from behind the collar of a pipe end portion. The retaining ring 36 is trapped or secured in a bore 42 of the housing by a fastening means such as in the form of a threaded fastener 44 which has a bore 46 oriented substantially coaxially with the bores of the housing. The bore 46 is larger in diameter than the external collar 14 and the deflectable fingers 38 are deflectable in a direction toward the O-ring, to at least the diameter of the external collar 14. Optionally, but preferably, a washer 48 is interpositioned between the deflectable fingers 38 and a second end 50 of the spring. The washer is disposed in a coaxial bore 52 of the housing which has a diameter that is greater than that of the external collar 14. The fastening means may also be used to secure the spring in its location in the housing as illustrated by FIG. 2, or alternately, a portion of the housing may be deformed 54 such as by staking, juxtaposed the washer 48 as illustrated in FIG. 6. Optionally, the fastening means may include a groove 55 for retaining a polymeric washer 56 with radial splits that define a plurality of radially inwardly extending deflectable fingers 58. The polymeric washer is oriented coaxially with the bore of the fastening means and the deflectable fingers define a means for inhibiting foreign material entering the housing when the coupling is in use with a pipe end portion. In use, the coupling and a pipe end portion are pushed together so that the external collar firstly, deflects the polymeric fingers; secondly, deflects the retaining ring fingers and thirdly, passes to a position beyond the retaining ring deflectable fingers as illustrated in FIG 4. The helical spring is further compressed as the external collar is pushed against the washer 48. The deflectable fingers of the retaining ring snap fit in toggle fashion behind the collar of the pipe end portion to retain and lock it in position in the coupling. FIG. 4 also illustrates the use of a second and optional O-ring 60 that is supported by a second back-up ring 62. While the second O-ring offers sealing redundancy, primary sealing is effected with a single O-ring which is best illustrated with reference to FIG. 5. As connected, the end 32 of the helical spring 30 presses against back-up washer 34 and thereby presses the O-ring 24 in sealing engagement against the shoulder 26. The O-ring is also in pressure contact with part of the pipe end portion 12 to effect a seal 64 therewith. The spring bias force must be sufficient to overcome an operating pressure times the annular area defined by the gap 66 between the housing and pipe end portion. It should be noted that the length of the seal effected by the O-ring of the invention is much less than the referenced prior art systems because the O-ring is only required to seal against the shoulder 26 and the outside diameter of the pipe end portion. Also, the O-ring 24 is not activated by operating fluid pressure to effect a seal. The spring biasing means constantly deforms the O-ring into its deflected position to effect a fluid tight seal that is effective over a temperature range from at least about -45°C (-40°F) to about +125°C (+250°F). To illustrate the effectiveness of the coupling of the invention, an 8mm (5/16") quick connect coupling with one O-ring was subjected to hot and cold testing as illustrated by way of the following two examples. Example I -- Hot Test Test Requirements: No air leakage at 1035 kPa (150psi) after vibrating coupling 100 hours, 1.5mm (0.06") amplitude, 30 cycles per second at 350 kPa (50psi),and 125°C (250°F). After completion, increase amplitude from 1.5mm (0.06") at a rate of 0.5mm/hour (0.019"/hour). Record amplitude where leakage occurs. Example II -- Cold Test Test Requirements: No air leakage at 1035 kPa (150psi) after vibrating coupling 100 hours, 1.5mm (0.06") amplitude, 30 cycles per second at 70 kPa (10psi), and -45°C (-40°F). After completion, increase amplitude from 1.5mm (0.06") at a rate of 0.5mm/hour (0.019"/hour). Record amplitude where leakage occurs. Additional Embodiment of the Invention Another embodiment of the invention is illustrated by FIG. 7. The coupling 70 operates substantially in the same manner as that previously described except that the coupling does not have a removable retaining means which permits the housing 72 of the coupling to be substantially foreshortened. A fastening means comprises a cupped member 74 with a bottom portion 76 having an opening 78 that is aligned with the bores of the housing. A side portion 79 of the cupped member encircles the housing and is staked at 82 which retains the cupped member to the housing. The bottom portion secures a retained ring 80 in the housing, together with the spring 30.

Claims: A female coupling (10) with a housing (18) having at least two substantially coaxial bores (20,22) for receiving a male end pipe portion (12) having a collar, one bore (22) being of larger diameter than the other bore so that the housing (18) has an annular shoulder (26) at the junction between the bores; at least one O-ring (24) in the housing to define a sealing means for the housing and said male end pipe portion (12) with the collar (14); and a retaining means (36) for retaining part of the inserted male end pipe portion (12) with the collar (14), the retaining means having deflectable fingers (38); characterised in that: the larger diameter bore (22) of the housing (18) is sized to receive the O-ring (24) without radial clearance; a spring bias means (30) in the housing (18) biases the O-ring (24) against a portion of the annular shoulder (26), thereby deforming the O-ring (24) to effect a seal with the shoulder, and the opposite end (50) of which is axially displacable by said collar (14) (12) by an amount at least equal to the desired collar thickness to permit insertion of said male end pipe portion; and the deflectable fingers (38) are juxtaposed the displaceable end (50) of the spring bias means (30), and are deflectable an amount at least equal to the desired collar height to accommodate said collar (14), and act as a means for engaging said collar (14) to effect retention of the inserted male end pipe portion. A female coupling (10) as claimed in claim 1 wherein the spring bias means includes a coiled compression spring (30) located in the larger diameter bore (22), the spring having a first end portion (32) juxtaposed a side portion of the O-ring (24) that oppositely faces the annular shoulder (26). A female coupling (10) as claimed in claim 2 wherein a portion (54) of the housing (18) at the larger diameter bore (22) is deformed radially inward juxtaposed a second end portion of the spring (30) and defines a means for retaining the spring (30) in the larger diameter bore (22). A female coupling (10) as claimed in claim 2 or claim 3 and including a first back-up ring (34) located in the larger diameter bore (22) between the O-ring (24) and first end portion (32) of the spring (30). A female coupling (10) as claimed in claim 4 and including a second O-ring (60) located in the housing (18) between the first back-up ring (34) and first end portion (32) of the spring (30). A female coupling as claimed in claim 5 and including a second back-up ring (62) located in the larger diameter bore (22) between the second O-ring (60) and first end portion (32) of the spring. A female coupling as claimed in any of claims 1-6 wherein the retaining means (36) comprises a retaining ring (36) located in the housing, the retaining ring having said deflectable fingers (38) which extend inwardly into at least part of the larger diameter bore (22) as a means for engaging part of said pipe end portion to effect retention. A female coupling as claimed in claim 7 wherein the retaining ring (36) is split. A female coupling as claimed in claim 7 or claim 8 and including a fastening means (44) for securing the retaining ring (36) in the housing. A female coupling as claimed in claim 9 wherein the fastening means (44) comprises a removable threaded fastener (44) attached to a threaded portion of the housing juxtaposed the retaining ring. A female coupling as claimed in claim 9 or claim 10 wherein the fastening means (44) includes a flexible polymeric washer (56), the polymeric washer having a plurality of radially inwardly extending deflectable fingers (58) as a means for inhibiting entry of foreign material into the housing. A female coupling as claimed in claim 9 wherein the fastening means (44) comprises a cupped member (74) with a bottom portion (76) having an opening (78) aligned with the bores and a side portion (79) encircling and staked to the housing. A female coupling as claimed in any of claims 1-4 including: a second O-ring (60) located in the housing with a first side portion abutting the first back-up ring (34) and a second side portion facing toward the coiled compression spring (30); and a second back-up ring (62) abutting the second side portion and interpositioned between the second O-ring (60) and first end portion of the coiled compression spring (30).

Inventors: ANTOSCH, JERRY J., CHOHAN, SATISH M.
Applicants: THE GATES RUBBER COMPANY
Application year: 1987
Main classification: F16L37
IPC codes: F16L37, F16B7