Apparatus relating to tube couplings

[00002] 1. Field of the Invention

[00003] This invention relates to couplings for receiving tubes or stuffer pins or the like such as disclosed in EP-A-00300504.8 and EP-A-756125.

[00004] 2. Background Prior Art

[00005] Our European patent publication no. 0829671, published on Mar. 18, 1998, and corresponding to U.S. Pat. No. 5,934,713, describes and illustrates a number of connectors for latching engagement with tubes or stuffer pins in which a tube must be pressed into the connector body sufficiently to engage a seal located in the body for the latching arrangement provided to operate and retain the tube in the body. Typically, a raised bead is provided on the tube with which the latch in the coupling body engages.

[00006] A number of users of such devices have requested that secondary latches be fitted to the connectors in certain applications such as in tube connectors used in motor vehicle engine compartments. For example, one user has a requirement that a secondary latch is engaged in a separate manual operation from the primary assembly operation of inserting a tube in the coupling body and that the secondary latch only operates properly if the tube has been inserted so the primary latch within the coupling body is successfully engaged.

[00007] It is an object of this invention to meet these additional requirements.

[00008] This invention provides a coupling for a tube or the like comprising a coupling body having a throughway open at one end to receive an end portion of a tube, sealing means mounted in the coupling body at a location spaced from said open end thereof to engage and seal with the outer periphery of the tube, and a tube latching device comprising first latching means disposed within the coupling body having at least one latch to engage automatically with a feature on the tube when the tube end portion has been inserted sufficiently into the throughway to engage with the sealing means to retain the tube end portion in the coupling body and second manually operable latching means disposed externally of the coupling body having a latch engageable with a feature on the tube when the end portion of the tube has been inserted into the coupling body sufficient for the first latch to engage to provide a secondary retention for the tube in the coupling body.

[00022] Referring firstly to FIGS. 1 to 6 of the drawings, there is shown a modified form of the tube coupling described as illustrated in our European patent publication No. 0829671 and in particular FIGS. 9 and 10 of that specification to which reference should be made. The coupling comprises a coupling body 10 having a stepped throughway 11 open at one end 12 of the coupling body to receive a tube end fitting indicated at 13. The tube end fitting in this case is a standard male end form to SAE (Society of Automotive Engineers) J2044. Other similar fittings are equally applicable. The throughway 11 is stepped at 14 to an elongated diameter portion 15 to receive the tube end 13 with a close or interference fit. The throughway is stepped at 16 to a second enlarged diameter portion 17 in which a pair of O-ring seals 18 are located with a spacer 19 between them to seal on the outside of the tube end 13. The throughway has a further step 20 to an enlarged diameter portion 21 which extends through to the open end of the throughway at 12.

[00023] The latching structure comprises a mounting element having a first position which extends into the coupling body 10 and a second position which extends over the coupling body 10. A first internal latch is located within the coupling body 10 and comprises a sleeve 22 extending through the enlarged diameter portion 21 of the throughway 11 and having a reduced diameter end portion to engage in portion 17 of the throughway. The sleeve has three integral resilient legs 24 disposed over three quarters of the circumference of the sleeve and projecting towards the open end of the coupling. The legs have latch members 25 at their distal end which have outwardly extending abutments which engage in radial openings 26 through the wall of the coupling body and have inwardly projecting teeth 25a to engage a raised annular abutment or bead 27 on the tube end. Reference should be made to our European patent publication no. 0829671 for a more detailed description of the form of the latch members and the manner of their engagement with the raised abutment on the tube end and in the openings 26 of the coupling body wall to retain the tube end in the coupling.

[00024] The sleeve 22 has integral struts 28 projecting between the teeth to the open end of the coupling body. The struts are formed integrally with a second position of a mounting element or end cap 30 encircling the end of the coupling body and which is adjustable axially on the coupling body to adjust the position of the internal latches for release of a tube end from the coupling body as described in our previous European publication.

[00025] As indicated above, the internal latches in the coupling body are provided over three quarters of the circumference of the sleeve. The remaining quarter of the sleeve is disposed opposite a slot 31 formed with the wall of the coupling body and a corresponding slot 32 formed in the wall of the cap. The wall of the cap has an extension 33 in alignment with the slot 32 and a leg 34 is attached to the extension by an integral hinge 35. The leg has a detent 36 at its distal end shaped to extend through the slots in the cap and coupling body and to engage the end of the tube behind the raised rib 27 to provide a secondary, external latch for holding the tube in place in the coupling body. The end of the detent 36 is radiused as shown at 37 with a corresponding radius to the tube end to provide a close engagement between the abutment and tube. The detent is formed with abutments 36a which snap behind abutments on either side of the slot in the coupling body to retain the detent in the engaged position. In the addition, the hinge 35 between the leg 34 and cap extension 33 has a moulded characteristic such that the leg 34 snaps towards the coupling body when adjacent the body and snaps outwardly of the body when withdrawn beyond an intermediate position in its travel, i.e., the hinge 35 also functions as an integral spring or integral spring means in the illustrated embodiment. The leg then stands outwardly of the coupling body and provides a clear visual or tactile indication that it is not engaged.

[00026] FIGS. 7 to 11 show a broadly similar arrangement except that in this case the tube end 13 has a second raised bead 40 beyond the first bead or abutment 27 and the detent 36 on the leg 34 is arranged to project beyond body in the closed position and to engage the tube end 13 beyond the second bead 40. Thus in this arrangement the tube abutment 27 does not fit between slots in the cap and coupling body so the coupling body may be provided with four internal latches to engage the bead 27 rather than three as the shown in the embodiment of FIG. 1-6. Also the detent is in the form of a C-shaped clip 41 which is a snap fit on the tube end. The arrangement is otherwise much the same as that of FIG. 1.

[00027] The arrangement of FIGS. 1 to 6 can also be adapted to have four latch members 25 within the coupling body and one pair of members spaced sufficiently to accommodate the external manual latch between them.

[00028] FIGS. 12 to 15 shows similar arrangements applied to stuffer pins rather than tube ends.