Quick connect coupling

Abstract: A unique quick connect fluid coupling (20) is disclosed in which a tube inner end (36) does not contact a seal (42) if the tube (22) is not partially connected. Preferably, a retainer (30) retains the tube (22) within a bore (46) in 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 carries it to its fully inserted position. No seal is formed between the tube and seals (42,44) within the housing (24) unless the tube (22) has moved beyond the point where the high force begins. The invention ensures that there would be no seal between a tube (22) and a housing (24) unless the tube is partially connected.

Description: The present invention relates to a quick connect fluid connector or coupling which ensures that a tube is not sealed unless the tube is fully inserted into a connector structure. Quick connect fluid couplings are well known in the art and used to quickly connect a tube to a housing or second tube. Several quick connect couplings are utilized in most modern vehicles to connect brake lines, air conditioning lines, power steering lines and other high pressure lines to a housing, or second tube. A particularly successful prior art coupling consists of a spring or retainer received within a female housing bore. The retainer has a plurality of arms which extend radially inwardly in a direction moving axially into the bore. The tube has a radially greater upset portion which moves into the bore and abuts an inner peripheral surface of the arms. The axially and radially innermost ends of the arms define an inner diameter approximately equal to the outer diameter of the tube at locations other than the upset portion. As the tube is inserted further into the bore, the upset portion forces the arms radially outwardly, and moves axially past the arms. Once the upset portion has moved axially beyond the arms, the arms spring back to a position where they are radially outwardly of the tube, and axially between the upset portion of the tube an outer end of the bore. The tube is then fully inserted, and the retainer securely retains the tube within the housing. In one prior art coupling, the retainer is of a so-called "avalanche" type where the force required to insert the tube into the housing is at a first relatively low point for initial axial insertion, and then rises sharply to a relatively high point after the upset portion initially contacts the inner periphery of the arms. The point where 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. In such couplings, e.g. as shown in GB-A-2087021, the seals engage the outer periphery of the tube and provides 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. The couplings described in GB-A-2216213 and US-A-4943091 aim to overcome the aforementioned disadvantages by providing couplings having the features in the preamble of claims 1 and 3. In accordance with a first aspect of the present invention, there is provided a quick connect tubing connector comprising: a quick connect tubing connector comprising: a tube extending along an axis, having a first outer diameter over the majority of an axial length, and having at least one upset portion of a greater radially outer dimension at one axial position, said one axial position being spaced from an inner axial end of said tube by a first distance; a body defining a bore to receive said tube, said bore extending from an outer end axially inwardly, a retainer positioned within said bore, at least one seal positioned within said bore, the centre of said at least one seal being located at a first axial position (x); said retainer comprising a plurality of resilient arms extending axially and radially inwardly from an axially outer end of said bore, said resilient arms having an inner peripheral surface with a greatest inner diameter that is greater than the outer diameter of said upset portion, and a smallest inner diameter that is less than the outer diameter of said upset portion, wherein said resilient arms provide sharply increased resistance to further inward insertion of said tube into said bore after said upset portion reaches a second axial position (y) where it abuts an inner peripheral surface of said arms having an inner diameter intermediate said greatest and smallest inner diameters, and approximately equal to the outer diameter of said upset portion, the distance (x-y) between said first and second axial positions being greater than said first distance such that said inner axial end of said tube does not sealingly engage said at least one seal when said upset portion is at said second axial location, and characterized in that said inner axial end of said tube is axially aligned with an axially outer portion of said at least one seal when said upset portion of said tube is at said second axial position (y), and that said inner axial end of said tube is bevelled such that said axially outer portion of said at least one seal is spaced radially outwardly of said inner axial end of said tube and such that a plane could be drawn normal to the axis of said tube, said plane extending through said axially outer portion of said at least one seal and said inner axial end of said tube and said tube is not retained in any intermediate positions by said body, said retainer or said at least one seal prior to said tube reaching said second axial position (y). In accordance with a second aspect of the present invention, there is provided a quick connect tubing connector comprising: a quick connect tubing connector comprising: a housing defining an axial bore extending inwardly into said housing from an entrance; sealing means within said bore; a tube insertable into said bore; a retainer associated with said tube and with said housing for retaining said tube in said bore; said retainer being positioned in said bore to define an avalanche point (y) of tube insertion, such that upon insertion of said tube into said bore to an axial position corresponding to said avalanche point (y), sharply increased resistance to further inward insertion of said tube is provided by said retainer, characterised in that said sealing means are positioned within said bore such that upon insertion of said tube into said bore to an axial position corresponding to said avalanche point (y) an axially outer portion of said sealing means is axially aligned with a bevelled surface at the inner end of said tube but radially spaced therefrom, and such that upon insertion of said tube to any axial position inward of said avalanche point (y), said sealing means are in sealing contact with said tube and with said housing, and further characterised in that said tube is not retained in any intermediate positions by said body, said retainer or said at least one seal prior to said tube reaching said second axial position (y). In a 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 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 outwardly, 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 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 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. By way of example only, a specific embodiment of the present invention will now be described, with reference to the accompanying drawings, in which:- Figure 1 is an exploded perspective view of an embodiment of connector or coupling in accordance with 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 in an uncoupled condition; Figure 4 is a view similar to Figure 3 in a partially coupled but unsealed condition; Figure 5 is a view similar to Figure 4, in a partially coupled but unsealed condition; and Figure 6 is a view similar to Figure 5, in a fully coupled condition. 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 a bushing or spacer 40, and sealingly engages O-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 centred 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 now 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 seal 42. Inner end 36 is bevelled, and a portion of its bevelled 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.

Claims: A quick connect tubing connector (20) comprising: a tube (22) extending along an axis, having a first outer diameter over the majority of an axial length, and having at least one upset portion (34) of a greater radially outer dimension at one axial position, said one axial position being spaced from an inner axial end (36) of said tube (22) by a first distance; a body (24) defining a bore (46) to receive said tube (22), said bore (46) extending from an outer end axially inwardly, a retainer (30) positioned within said bore (46), at least one seal (42) positioned within said bore (46), the centre of said at least one seal (42) being located at a first axial position (x); said retainer (30) comprising a plurality of resilient arms (32) extending axially and radially inwardly from an axially outer end of said bore (46), said resilient arms (32) having an inner peripheral surface (52) with a greatest inner diameter that is greater than the outer diameter of said upset portion (34), and a smallest inner diameter that is less than the outer diameter of said upset portion (34), wherein said resilient arms (32) provide sharply increased resistance to further inward insertion of said tube (22) into said bore (46) after said upset portion (34) reaches a second axial position (y) where it abuts an inner peripheral surface of said arms (32) having an inner diameter intermediate said greatest and smallest inner diameters, and approximately equal to the outer diameter of said upset portion (34), the distance (x-y) between said first and second axial positions being greater than said first distance such that said inner axial end (36) of said tube (22) does not sealingly engage said at least one seal (42) when said upset portion (34) is at said second axial location, and characterized in that said inner axial end (36) of said tube (22) is axially aligned with an axially outer portion of said at least one seal (42) when said upset portion (34) of said tube (22) is at said second axial position (y), and that said inner axial end (36) of said tube (22) is bevelled such that said axially outer portion of said at least one seal (42) is spaced radially outwardly of said inner axial end (36) of said tube (22) and such that a plane could be drawn normal to the axis of said tube (22), said plane extending through said axially outer portion of said at least one seal (42) and said inner axial end (36) of said tube (22) and said tube (22) is not retained in any intermediate positions by said body, said retainer or said at least one seal prior to said tube (22) reaching said second axial position (y). A quick connect tubing connector (20) as claimed in claim 1, wherein said at least one seal (42) is an axially outermost seal, and there is at least one additional seal (44) spaced axially inwardly from said axially outermost seal (42). A quick connect tubing connector (20) comprising: a housing (24) defining an axial bore (46) extending inwardly into said housing (24) from an entrance; sealing means (42,44) within said bore (46); a tube (22) insertable into said bore (46); a retainer (30) associated with said tube (22) and with said housing (24) for retaining said tube (22) in said bore (46); said retainer (30) being positioned in said bore (46) to define an avalanche point (y) of tube insertion, such that upon insertion of said tube (22) into said bore (46) to an axial position corresponding to said avalanche point (y), sharply increased resistance to further inward insertion of said tube is provided by said retainer (30), characterised in that said sealing means (42,44) are positioned within said bore (46) such that upon insertion of said tube (22) into said bore (46) to an axial position corresponding to said avalanche point (y) an axially outer portion of said sealing means (42,44) is axially aligned with a bevelled surface at the inner end (36) of said tube (22) but radially spaced therefrom, and such that upon insertion of said tube (22) to any axial position inward of said avalanche point (y), said sealing means (42,44) are in sealing contact with said tube (22) and with said housing (24), and further characterised in that said tube (22) is not retained in any intermediate positions by said body, said retainer or said at least one seal prior to said tube reaching said second axial position (y). A quick connect tubing connector (20) as claimed in claim 3, wherein an upset portion (34) of relatively large diameter is formed on said tube (22), and said retainer (30) includes resilient arms (32) extending radially inwardly, said upset portion (34) deforming said resilient arms (32) radially outwardly when said tube (22) is at an axial point of insertion corresponding to said avalanche point (y), such that said tube (22) may be further inserted to a fully inserted position wherein said upset portion (34) is positioned inwardly of said arms (32), and wherein said arms (32) are relaxed to a non-deformed position and abut said upset portion (34) to prevent withdrawal of said tube (22) from said bore (46). A quick connect tubing connector (20) as claimed in claim 3 or claim 4, wherein said retainer (30) is constructed such that upon insertion of said tube (22) into said bore (46) to any axial position inward of said avalanche point (y), said tube (22) will necessarily be moved to said fully inserted position without being retained at any intermediate positions.

Inventors: MCNAUGHTON JAMES, PACITTO ANGELO, MCNAUGHTON, JAMES, PACITTO, ANGELO
Applicants: BUNDY CORP, BUNDY CORPORATION
Application year: 1992
Main classification: F16L37
IPC codes: F16L37