POSITIVE TRANSITION QUICK CONNECT COUPLING

Abstract: Two unique quick connect fluid coupling embodiments have a tube inner end (36) which does not contact a seal (42, 44) if the tube (22) is not fully connected. Preferably, a retainer retains the tube (22) within the bore of a housing (24). The retainer (30) is of the avalanche type such that a high force is required to insert the tube (22), and once this high force is overcome the momentum of the tube (22) carries it to its fully inserted position. No seal is formed between the tube (22) and seals (42, 44) within the housing (24) unless the tube (22) has moved beyond the avalanche point where the high force begins. Once the tube (22) has moved beyond that point, it will be fully connected. The invention ensures that there would be no seal between a tube (22) and a housing (24) unless the tube (22) is fully connected.

Description: POSITIVE TRANSITION QUICK CONNECT PIPING This is a continuation-in-part of United Stat Patent Application Serial No. 07/751,196, filed on August 2 1991. BACKGROUND OF THE INVENTION This application relates to a quick connect flu coupling which ensures that a tube is not sealed unless t tube is fully inserted into a connector structure. Quick connect fluid couplings are well known in t art and used to quickly connect a tube to a housing or seco tube. Several quick connect couplings are utilized in mo modern vehicles to connect brake lines, air conditioni lines, power steering lines and other high pressure lines a housing, or second tube. A particularly successful prior art coupli consists of a spring or retainer received within a fema housing bore. The retainer has a plurality of arms whi extend radially inwardly in a direction moving axially in the bore. The tube has a radially greater upset porti which moves into the bore and abuts an inner peripher surface of the arms. The axially and radially innermost en of the arms define an inner diameter approximately equal the outer diameter of the tube at locations other than t upset portion. As the tube is inserted further into t bore, the upset portion forces the arms radially outwardl and moves axially past the arms. Once the upset portion h moved axially beyond the arms, the arms spring back to position where they are radially outwardly of the tube, a axially between the upset portion of the tube an outer end the bore. The tube is then fully inserted, and the retain securely retains the tube within the housing. In one prior art coupling, the retainer is of a s called "avalanche" type where the force required to inse the tube into the housing is at a first relatively low poi for initial axial insertion, and then rises sharply to relatively high point after the upset portion initial contacts the inner periphery of the arms. The point whe this high required force begins is defined as an "avalanche" point. Once an operator has supplied sufficient force to overcome this high required force, the momentum carries the tube further axially inwardly and ensures that it is fully inserted. Problems are sometimes encountered with this type of quick connect coupling since a tube inner end is at an axial position where it is aligned with seals in the housing prior to reaching the avalanche point. The seals engage the outer periphery of the tube and provide some resistance to further insertion of the tube. This may give a false impression or feel to the assembler that the high required force may have been overcome. Thus, the prior art has sometimes resulted in an assembler misinterpreting this feel as an indication that the tube is fully inserted. Further, if an assembler neglects to fully insert the tube for whatever reason, it is still possible that the prior art couplings will provide a seal between the tube and the housing. It is undesirable for the tube not to be fully inserted since it could become disconnected in use. This is particularly true when the tube is used in a vehicle. With the prior art structure discussed above, should the tube not be fully inserted within the housing, a seal may still be provided between the housing and the tube. The seal may be adequate for a period of time until the vehicle has driven off the assembly line and away from the factory. The fluid pressure in the line, vibration or temperature cycling, will eventually cause the tube to become disconnected from the housing. It is far more preferable for the improper connection to be identified before the vehicle leaves the assembly line. SUMMARY OF THE INVENTION In one disclosed embodiment a quick connect fluid coupling does not provide a seal between a tube and a housing until the tube has moved beyond a point where it will be fully inserted. In one disclosed embodiment, a required tube insertion force begins at a low level, then increases sharply to a relatively high level at a first axial position. Once this relatively high level of force is overcome, momentum carries the tube to its fully inserted position. The axially innermost end of the tube is not received within a seal in the housing until the tube passes this first axial position. Thus, no false feel is given to an operator that the tube is fully inserted. Moreover, if the tube is not fully inserted there is no seal. If the vehicle is moved off of an assembly line, the high pressure fluid will noticeably leak. The tube preferably has a radially greater upset portion spaced from an inner axial end. The retainer preferably has a number of resilient arms which extend radially inwardly from an outer end of the bore axially into the bore. The tube is inserted until the upset end initially contacts an inner peripheral surface of these arms. This initial insertion is the low level required force discussed above. This point is the first axial position, or avalanche point. Further insertion of the tube requires the upset portion to bias the arms radially outward, which requires the sharply increased tube insertion force. As the tube moves beyond the avalanche point, the upset portion of the tube begins to bias the arms radially outwardly. The axially innermost end of the tube may then move into a first seal. As noted above, once this avalanche point is passed, the momentum of the tube carries it to its fully assembled position. Thus, it is desirable that the seal begin contacting the tube soon after the avalanche point is passed. Further, any resistance to the tube insertion from the seal will occur within the area where the sharply increased force is provided. Thus, the resistance from the seal will be easily overcome, and will not provide a false feel to an operator. In a most preferred embodiment of the present invention, the axially innermost end of the tube is adjacent to the axially outermost end of a first seal when the tube reaches this avalanche point. This preferred alignment of the seal and axial end of the tube results in the greatest amount of sealing possible, while still not providing a seal until the tube is fully inserted. In a second embodiment, the tube has two stepped diameters positioned inwardly from the upset portion. Seals are positioned within the housing and associated with each of these two stepped portions. An axially outer seal is positioned radially outwardly from the radial position of an axially inner seal. The two stepped tube includes an inner portion which is radially smaller than an outer or body portion positioned between the inner portion and the upset portion. When the tube is inserted into the housing and the upset portion initially contacts the retainer, the inner portion may be axially aligned with the outer seal, which is adapted to contact the outer portion. This seal will not sealingly engage the inner portion, however, as it is positioned radially outwardly from the outer peripheral service of the inner portion. Thus, no seal will be made at that position. Once the tube moves further in, and the upset portion deforms the resilient arms radially outwardly, the inner portion of the tube will sealingly engage the axially inner seal. Further, the body portion of the tube will sealingly engage the outer seal. Thus, due to the unique construction of the tube and the positioning of the seals, two good seals are obtained after the relatively short axial movement. This may sometimes provide advantages over the first disclosed embodiment wherein the tube inner end must generally move through a longer axial length. These and other objects and features of the present invention can be best understood from the following specification and drawings, of which the following is a brief description. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exploded perspective view of a construction embodying a first embodiment of the present invention. Figure 2 is a cross-sectional view of a portion of the construction shown in Figure 1. Figure 3 is a cross-sectional view of the construction shown in Figure 1. Figure 4 is a view similar to Figure 3. Figure 5 is a view similar to Figure 4. Figure 6 is a view similar to Figure 5. Figure 7 is a cross-sectional view of a second embodiment of this invention. Figure 8 is a view similar to Figure 7. Figure 9 is a view similar to Figure 7. Figure 10 is a view similar to Figure 7. Figure 11 is a cross-sectional view of a portion of the construction shown in Figure 7. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Figure 1 discloses a quick connect fluid coupling 20 for connecting a tube 22 within a housing 24. Housing 24 has structure 26 at a downstream end to be connected to a downstream tube 28. A retainer 30 is inserted within housing 24 and includes a plurality of arms 32 which extend radially inwardly to abut an upset portion 34 of tube 22. Upset portion 34 is of a greater radial outer diameter than portions on either axial side of upset portion 34. An inner tube end 36 extends through an opening 38 in retainer 32, through spacer 40, and sealing engages 0-ring seals 42 and 44 to provide a fluid tight seal between tube 22 and housing 24. As shown in Figure 2, retainer 30 is inserted within bore 46 in housing 24. Bushing 40 and O-rings 42 and 44 are positioned in bore 46 axially inwardly of retainer 30. As shown in Figure 3, coupling 20 is assembled by inserting tube 22 into bore 46. Inner end 36 will eventually sealingly engage seals 42 and 44. As shown in Figure 4, tube 22 may be easily inserted into bore 46 until upset portion 34 initially contacts an inner peripheral surface of an arm 32. An outermost O-ring 42 is centered at a first axial position x. The location y on the inner periphery of arms 32 which upset portion 34 initially contacts is defined as a second axial position. The distance x-y between the first and second axial positions is greater than the distance between upset portion 34 and inner end 36 of tube 22. Thus, when upset portion 34 initially contacts the inner peripheral surface of arms 32, inner end 36 does not sealingly engage the outermost seal 42. At this point there is no seal provided between tube 22 and housing 24. The point where upset portion 34 reaches second axial position y is known as the avalanche point. Up to this point the insertion force was low, it will not increase sharply. As tube 22 continues to be inserted, upset portion 34 begins to bend arms 32 radially outwardly. This is known as the positive transition zone and is illustrated in Figure 5. A sharply increased force is required over the force required to insert tube 22 to the position shown in Figure 4. As upset portion 34 is biasing arms 32 radially outwardly, inner end 36 of tube 22 begins to move within O-rings 42 and 44 and is sealingly engaged within housing 24. Thus, as tube 22 is moving through the positive transition zone where the sharply increased force is required inner end 36 is also being forced into seals 42 and 44. Any resistance to insertion of tube 22 from seals 42 and 44 will occur during this sharply increased force zone, and thus the resistance by the seals will not provide any false feel to an assembler. As shown in Figure 5, a first radially inwardly inclined surface 52 is formed on arms 32 and extends to a second surface 54 which is formed at an angle generally parallel to the axis of the bore. Once upset portion 34 reaches the apex between portions 52 and 54, the force resisting insertion of tube 22 decreases rapidly. Upset portion 34 then snaps beyond second inclined portion 54 into a fully inserted position. The force required to move tube 22 beyond the initial avalanche point, such as shown in Figure 4, and through the positive transition zone, shown in Figure 5, carries tube 22 to its fully inserted position shown in Figure 6. Tube 22 is now fully inserted into housing bore 46. Upset portion 34 is received axially inwardly of an axially innermost end of arms 32. Tube 22 is securely retained within housing 24. Moreover, the axially inner end 36 of tube 22 is received radially inwardly of seals 42 and 44 providing a fluid tight seal. As illustrated in Figures 4 and 5, when tube 22 has upset portion 34 at the second axial position y, or avalanche point, inner end 36 is spaced slightly from seals 42. Inner end 36 is beveled, and a portion of its beveled surface is axially aligned with an axially outer portion of outermost seal 42. Seal 42 is still spaced radially from inner end 36. Once upset portion 34 begins to bias arms 32 radially outwardly into the positive transition zone, as shown in Figure 5, inner end 36 immediately contacts the outermost seal 42. As shown in Figure 6, once fully inserted inner end 36 is spaced axially inwardly from the outermost seal 42 by the maximum distance that still provides no seal until upset portion 34 moves into the positive transition zone. Referring now to Figures 7-11, there is shown a quick connect tubing connector assembly 60 made in accordance with the teachings of a second embodiment of this invention. Specifically, assembly 60 includes a tube 62 having a beveled end 63 adjacent an inner portion 64 of a relatively small diameter and a body portion 66 of a relatively large diameter. As further shown, an upset portion 68 having a diameter greater than either the diameter of body portion 66 or inner portion 64 is positioned outwardly of body portion 66. Upset portion 68 is spaced a predetermined distance 70 from inner portion 64. As further shown, assembly 60 includes housing 24 and retainer 30, including a plurality of resilient arms 32. As previously described, housing 24 provides a bore 46 having an opening 72, adapted to receive and secure tube 62 within bore 46. An inner seal 74 is positioned axially and radially inwardly from an outer seal 76. Inner seal 74 and outer seal 76 are both received in housing 24, with inner seal being thicker than thinner outer seal 76. As shown in Figure 7, with the tube 62 initially inserted, inner portion 64 is axially aligned with outer seal 76. Outer seal 76 does not contact inner portion 64, and thus no seal is provided at this point. This position corresponds to the avalanche point. Once upset portion 68 begins to bias arms 32 radially outwardly, as shown in Figure 8, inner portion 64 begins to contact inner seal 74 and body portion 66 begins to contact outer seal 76. As further shown in Figure 9, upon further insertion of tube 62 the seals are fully made on tube 62. Figure 10 shows the connector after application of fluid pressure. With the inventive arrangement of the two stepped tube 62, and the positioning of seal 74 and 76, one ensures that the seals are disposed axially upwardly far enough on the outer peripheral surface of tube 62, while still not requiring a great deal of tube travel past the avalanche point shown in Figure 7. It is sometimes desirable to minimize the total movement between the avalanche point such as shown in Figure 7, and the fully connected position such as shown in Figures 9 and 10. Further, it is sometimes desirable to ensure that the seals are positioned axially far upwardly along the outer peripheral surface of tube 62. The unique arrangement of the two stepped tube end provides both benefits. As shown in Figure 11, tube 62 includes two stepped portions including inner portion 64 and body portion 66, with a distance 70 defined between the axially outer end of inner portion 64 and the axially inner end of upset portion 68. Preferred embodiments of the present invention have been disclosed, however, a worker of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Thus, the following claims should be studied in order to determine the true scope and content of the invention. CLAIMS 1. A quick connect tubing connector assembly comprising: a tube having a first outer diameter over the majority of its axial length, and an upset portion of a greater diameter over a limited portion of its axial length; a housing including a bore to receive said tube, a retainer positioned within said housing and having arms extending axially and radially inwardly from an axially outer end of said housing, said arms being biased radially outwardly by said upset portion of said tube when said tube is inserted into said housing, said upset portion contacting said retainer to begin biasing said arms radially outwardly at a first position; and at least one seal positioned within said housing, said seal being positioned at an axial position such that it does not sealingly contact said tube when said upset portion is at said first position, but does contact said tube when said tube is fully inserted within said housing. 2. A quick connect tubing connector assembly comprising: a tube having an inner portion of a first diameter and a body portion positioned axially outwardly of said inner portion and of a second larger diameter; a housing defining a bore for insertably receiving said tube;

Claims: a quick connect structure for quickly connecting said tube within said housing; and a first seal positioned within said housing and effective to sealingly engage said inner portion of said tube when said tube is fully connected with said housing, but not engaging said inner end of said tube if said tube is not fully connected within said housing, and a second seal position within said bore and effective to sealingly engage said body portion if said tube is fully connected within said housing, but not if said tube is only partially connected within said housing. 3. A quick connect tubing connector as recited in Claim 2, wherein said quick connect structure is a retainer having resilient arms extending radially inwardly, said tube having an upset portion of a diameter greater than said second diameter, said upset portion biasing said arms radially outwardly such that said tube can move axially beyond said retainer to a fully connected position, and said upset portion abutting said retainer at a first position such that said upset portion begins to deform said resilient arms radially outwardly, said inner portion and said body portion not contacting either said first or second seal, when said upset portion is at said first position. 4. A quick connect tubing connector as recited in Claim 3, wherein said inner portion is axially aligned with said second seal, but does not sealingly contact said second seal, when said upset portion is at said first position. 5. A quick connect tubing connector as recited in Claim 4, wherein said first seal has a greater diameter than said second seal. 6. A quick connect tubing connector as recited in Claim 3, wherein said retainer is constructed such that once said upset portion has moved axially inwardly beyond said first position, said tube will necessarily reach aolully connected position with said upset portion being positioned axially inwardly from an axially inner end of said arms, said tube not being retained in any intermediate positions. 7. A quick connect tubing connector assembly comprising: a tube having an inner portion of a first diameter and a body portion positioned outwardly of said inner portion and of a second larger diameter, said tube having a raised upset portion having a third diameter greater than said second diameter and positioned outwardly of said body portion; a housing including a tube reception bore having an opening insertably receiving said tube; a retainer removably positioned with said bore and having a plurality of resilient arms movable between a first position in which said arms cooperatively resist insertion of said tube within said bore to a second position at which said arms allow said tube to be inserted into said bore; a first seal positioned within said bore effective to sealingly engage said inner portion only after said plurality of resilient arms has moved to said second position; and a second seal positioned within said bore effective to sealingly engage said body portion only after said plurality of resilient arms has moved to said second position. 8. A quick connect tubing connector as recited in Claim 7, wherein said inner portion is axially aligned with said second seal, but does not sealingly contact said second seal, when said upset portion initially contacts said resilient arms. 9. A quick connect tubing connector as recited in Claim 8, wherein said first seal has a greater diameter than said second seal.

Inventors: KETCHAM MARK G, MCNAUGHTON JAMES, PACITTO ANGELO, KETCHAM, MARK, G., MCNAUGHTON, JAMES, PACITTO, ANGELO
Applicants: BUNDY CORP, BUNDY CORPORATION
Application year: 1993
Main classification: F16L39
IPC codes: F16L37