Abstract:
A coupling is designed for sealingly connecting two fluid conduits such as automotive fluid lines in axial end-to-end relationship. The conduits have respective telescopically interengaging male and female end sections and the coupling comprises a base member to be carried on one of the fluid conduits and a retaining structure mounted on the base member and having two C-shaped arms which can be interconnected around the other conduit end section. A releasable lock acts between the arms to lock the retaining structure in engagement. In the locked condition the axially oriented abutment surfaces in the retaining structure engage peripheral shoulders on the conduits to prevent axial separation of the latter. The coupling can be fabricated from integral plastic components and preferably includes a guard arrangement to shield the releasable lock against inadvertent disengagement.

Description:
BACKGROUND OF THE INVENTION 
   a) Field of Invention 
   This invention relates to a new or improved coupling for sealingly interconnecting two fluid conduits in axial end-to-end relationship. 
   b) Description of the Prior Art 
   Automotive fluid lines are typically joined by metal connectors. These are bulky in size and may require extensive brazing or may have multiple components (e.g. springs, collars or bolts) which result in the end product being heavy and quite costly. Furthermore many such couplings that are currently available do not ensure sufficient concentricity between the ends of the conduits so that the joined forms will eventually leak. 
   Automotive fluid line couplings currently employed are disclosed in U.S. Pat. Nos. 5,647,612 and 6,155,607. 
   The couplings shown in U.S. Pat. No. 5,647,612 is fabricated from plastic and includes as a retaining feature an over-molded metal component. However this coupling is not capable of sustaining the concentricity of the tube axes against shifting, so that leakage will eventually result. Furthermore high pressure forces within the tubes produce loads which are concentrated on the snaps and the hinge, potentially causing ultimate failure of the coupling. 
   U.S. Pat. No. 6,155,607 shows a quick connect coupling that includes a compression joint. However this coupling requires excessive force to interconnect the tubes, and under high pressure excessive forces are transferred to the snaps. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide an improved coupling which overcomes some or all of the disadvantages of known prior art couplings. Desirably the improved coupling provides for easy interconnection of fluid conduits in end-to-end relationship while ensuring sealing integrity. The coupling can be pre-assembled to the tube ends prior to their union and desirably is capable of sustaining high operating pressures within the conduits. Furthermore desirably the coupling will provide strong resistance against skewing or axial misalignment of the tubes after assembly, will not hinder the sealing of the joint or O-ring performance, and will be reusable. 
   In summary, the invention provides a coupling for sealingly connecting two fluid conduits in co-axial end-to-end relationship, wherein the conduits have respective male and female end sections that are configured for telescopic interengagement, each of the conduit end sections having an external peripheral shoulder, said coupling comprising: a base member adapted to be carried on a first one of the fluid conduits adjacent and engaging the peripheral shoulder thereof; and a retaining structure comprising two C-shaped arms that are interengageable in confronting relationship to clampingly grip said base member, said arms including a releasable lock that is operative to lock said retaining structure in engagement with said base member, said retaining structure defining an axially oriented abutment surface for contacting the peripheral shoulder of the second of the conduits when the two conduits are telescopically interengaged and prevent axial separation of the conduits when the retaining structure is in locked condition. 
   The C-shaped arms are preferably pivotally interconnected on a pivot axis that is defined by an axially oriented pin carried in the base member. The coupling components are preferably fabricated each as an integral plastic structure. The releasable lock may comprise a tooth carried on a resilient finger on one of the arms and a retainer on the other of the arms arranged such that when the arms are swung towards the locked position the finger engages and is deflected by the container until the tooth passes the retainer whereupon the finger is resiliently restored to engage the tooth with the retainer and secure the coupling in installed condition. A guard may be incorporated to protect the lock mechanism and prevent accidental or unauthorized opening of the coupling, possibly by requiring a special tool, while retaining easy assembly. The base member can be designed to be pre-installed on one of the fluid conduits, or can be designed in two parts adapted to be assembled in a radial direction onto the fluid conduit and so can be attached to it after forming that is carried out on the fluid conduit end e.g. to form a projecting peripheral shoulder thereon. 
   The coupling is preferably designed to be reusable and capable of being adapted to any male or female conduit end form. The coupling is designed to divert operational loads (such as arise due to the pressure within the conduits) from the snaps or retainers and hinges and absorb them in more robust portions of the coupling. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will further be described, by way of example only, with reference to the embodiments illustrated in the accompanying drawings, wherein: 
       FIG. 1A  is an exploded perspective view of one embodiment of the coupling in accordance with the invention; 
       FIG. 1B  is a perspective view of the assembled coupling; 
       FIG. 2  is a perspective view of the coupling of  FIG. 1  showing partially installed to interconnect two conduits end-to-end; 
       FIG. 3A  is a side view corresponding to  FIG. 2 ; 
       FIG. 3B  is a sectional view taken on the line X—X in  FIG. 3A  in the direction of the arrows B; 
       FIG. 3C  is a sectional view taken on the line X—X in  FIG. 3A  in the direction of the arrows C; 
       FIGS. 4A ,  4 B, and  4 C are views similar to  FIGS. 3A ,  3 C and  3 B respectively showing the coupling in assembled condition; 
       FIG. 5A  is an exploded perspective view showing a second embodiment of the coupling; 
       FIG. 5B  is a perspective view of the coupling of  FIG. 5A  when partly assembled; 
       FIG. 5C  is a perspective view of the coupling of  FIG. 5A  when fully assembled; 
       FIG. 6  is a perspective view showing the coupling according to  FIG. 5  in installed condition; 
       FIG. 7A  is a side view of the coupling of  FIG. 5  assembled on two conduits; 
       FIG. 7B  is an enlarged fragmentary sectional view taken on the line Y—Y in  FIG. 7A ; 
       FIG. 8A  is a plan view corresponding to  FIG. 7 ; and 
       FIG. 8B  is an enlarged fragmentary sectional view taken on the line Z—Z in  FIG. 8A ; 
       FIG. 9A  is a perspective view of a modified coupling shown when partly assembled; 
       FIG. 9B  is a view similar to  FIG. 9A  showing a successive condition of the coupling; and 
       FIG. 9C  is a view corresponding to  FIGS. 9A and 9B  showing the coupling when fully assembled. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The coupling indicated at  10  in  FIG. 1B  is shown in compact condition with the components interengaged as they would be when the coupling is in operation. The individual components however are shown more clearly in the exploded view of FIG.  1 A and will be seen to comprise four principal elements namely a base  12 , a base retainer  14 , and first and second clamping arms  16 ,  18 . 
   The base has a stepped cylindrical bore  20  having a larger diameter section  22  and a smaller diameter section  24  joined through a tapered frusto conical portion  26 . 
   All four of the components  12 ,  14 ,  16  and  18  are fabricated as injection molded plastic parts, suitable materials being polyaramid (nylon) glass filled, polyurethane, styrene/acrylonitrile copolymer (crystalline or amorphous resins). 
   As is seen in  FIG. 1A  the base has a thick peripheral wall that surrounds the stepped cylindrical bore over most of the length of the latter. However at one end the base has a cylindrically curved tubular extension  28  which terminates in a relatively thick radially projecting peripheral flange  30 . 
   The base retainer  14  has a shape that is complementary to that of the base  12  so that together the components  12  and  14  make up a complete annular structure with portions of the stepped bore, the tubular extension  28  and the flange  30  being formed in both the base  12  and the base retainer  14 . 
   An axially projecting pin  32  of the base  12  extends beyond the collar  30  as is best seen in FIG.  3 A. As seen in  FIG. 1A  the pin  32  has a diametral slot  34  opening from its free end, the periphery of the slotted portion of the pin carrying radial projections  36 . As is more fully described below, the axial pin  32  is designed to provide a pivotal mounting for the two remaining components of the coupling namely the first and second clamping arms  16 ,  18 . 
   With reference to  FIG. 1A  the clamping arms  16  and  18  are each seen to be of somewhat C-shape having a half bore which contains a small diameter section  38 , a large diameter section  40 , and a deep arcuate groove  42 . To this extent the arms  16  and  18  are complementary and designed to enclose and closely surround the tubular extension  28  and flange  30  of the base/base retainer assembly  12 ,  14 , the flange  30  being received in the arcuate groove  42 . 
   The clamping arm  16  has a pair of projecting bored mounting lugs  44  which are axially spaced by a distance corresponding to the axial length of a projecting bored mounting lug  46  on the clamping arm  18 . It will be understood that for assembly of the coupling the projecting lug  46  is positioned between the lugs  44  with their bores brought into axial alignment and the clamping arms  16 ,  18  are then moved axially to slide the clamping lugs  44 ,  46  onto the axial pin  32 . The bores in the lugs  44 ,  46  are sized to receive the axial pin  32  with a slight clearance. During assembly, the slot  34  in the end of the pin  32  enables inward flexure of the end portions of the pin so that the radial projections  36  can pass through the aligned bores of the lugs  44 ,  46  to project laterally axially beyond the outermost of the lugs  44 , whereupon the resilient force of the plastic material of the pin will cause the portions of the slotted end of the pin  32  to move outwardly so that the radial projections  36  will now act as retainers to prevent accidental removal of the lugs  44 ,  46  from the pin  32 . 
   The clamping arm  16  is formed with a pair of through openings  48 , these being of rectangular profile and opening from a generally diametrical planar surface of the arm  16 . 
   The clamping arm  18  is formed with a pair of tangentially projecting resilient latches  50  each of which has a thickened end defining a ramp surface  52  adjacent which is a notched tooth  54 . 
   From the foregoing description and the drawings it will be appreciated that when the clamping arms  16  and  18  are mounted on the pin  32  as illustrated in FIG.  2  and swung towards each other, the tip portions of the latches  50  will enter the through holes  48  in the clamping arm  16  and be deflected by engagement of the ramps  52  on the latches against the edges of the holes  48 . Continuous pivotal movement of arms  16 ,  18  towards one another will bring their radial faces into contact at the same time as the latches  50  pass through the opposite end of the holes  48 , whereupon the resilience of the material of the latches  50  causes them to straighten so that the notched teeth  54  provide an abutment against the arm  16  by overlapping arm  16  at the edges of the holes or openings  48 , which act as retainers, thus maintaining the arms  16  and  18  in firm engagement with each other. This is the configuration that is represented in  FIG. 1B  of the drawings. The latches  50  therefore operate as a lock to secure the coupling  10  in its engaged position with respect to the conduits  58  and  60  as shown in  FIGS. 4A  to  4 C. Providing two latches  50  increases the security of the connection, since in the (unlikely) event that one of the latches  50  should become displaced out of its locking abutment with respect to the clamping arm  16 , the integrity of the connection will nevertheless be guaranteed by the action of the second latch  50 . 
   It will be observed particularly from  FIG. 4C  that the components of the coupling engage the conduits  58 ,  60  over a substantial axial length, in the case of the clamping arms  16 ,  18  more than twice the diameter of the conduit  58 , and in the case of the base/base retainer  12 ,  14  more than four times the diameter of the conduit  60 . This plus the tight form locking interengagement of the arms  16 ,  18  with the tubular extension  28  and flange  30  of the base provides an initial safeguard against any tendency for misalignment to occur between the axes of the conduits  58  and  60 . 
   The assembly of the coupling  12  onto the ends of a pair of coaxial conduits is now described with particular reference to FIG.  2  and  FIGS. 3A  to  3 C and  FIGS. 4A  to  4 C. 
   The conduits  58 ,  60  are typically metal tubes with end formations to facilitate their interengagement. As is more clearly shown in  FIGS. 3 and 4 , the conduit  58  has a thickened end section  62  which is grooved and carries three O-ring seals  64 , the thickened portion  62  terminating in a projecting rounded annular rib  66 . The conduit  60  has a tapered transition section  68  leading to a widened elongate end section  70  which tube end forms terminates in a flared annular lip  72 . Alternate detailed shapes of the tube end forms, including the shape of the O-ring grooves and their number, are well known in the field and can be accommodated by the present coupling. 
   Thus, when the conduits  58 ,  60  are assembled as shown in  FIG. 3B  the end section  62  is inserted into the end section  70  of conduit  60  until the annular rib  66  comes into engagement with the flared lip  72 . The diameters of the end sections  62  and  70  of the conduits are closely matched to ensure good alignment between the conduits  58  and  60  and the annular seals  64  engage against the inner cylindrical surface of the end section  70  providing protection against the escape of fluid from the interior of the conduits. 
   The shape of the end section of the conduit  60  corresponds to the interior shape of the bore sections  22 ,  26 ,  24  of both the base  12  and the base retainer  14  so that the latter can be assembled together onto the conduit  60  as shown in  FIGS. 3 and 4 , in which configuration they completely surround the end section  60  of the conduit, the flared lip  72  of the conduit being received in a matching chamfer  74  (see  FIG. 3C ) at the end of the enlarged bore  22 . 
   With the clamping arms  16  and  18  mounted on the pivot pin  38  as shown in  FIGS. 2 and 3   a , the coupling could then be installed by springing those arms about the pin  38  as previously described to bring the arms into close engagement around the conduit  58 . The projecting annular rib  66  of the conduit  58  abuts the flared lip  72  of the conduit  60 , and the arms when locked together by the latches  50  as described above closely surround the conduit  58  and the tubular extension  28  and flange of the base/base retainer  12 ,  14 . Specifically, the bore sections  38  closely surround the conduit  58 , an end chamfer portion  39  (see  FIG. 2 ) abutting against the left hand side of the annular rib  66  thus securing the conduit  58  against withdrawal. At the same time the larger bore portions  40  of the arm  16 ,  18  closely surround the tubular extension  28  and the annular flange  30  is received within the annular recess formed by the arcuate grooves  42 . 
   From the foregoing description and drawings it will be evident that the coupling  10  provides a very secure and leak-proof connection between the formed ends of the conduits  58  and  60 . Axial alignment between the conduits is ensured by the substantial overlap and close fit between the complementary end sections  62  and  70 , and also by the substantial axial length and the close form locking interconnection between the clamping arm  16 ,  18 , and the base/base retainer  12 ,  14 . Withdrawal of the conduits  58  and  60  from the latched coupling is impossible due to the abutment formed by various surfaces of the coupling with the end section formations of the conduits. Furthermore it will be noted that loads imposed on the coupling due to pressure forces arising within the bores of the conduits does not stress the mechanism of the latches or pivot pin  34 , since these forces act in the longitudinal direction whereas the locking movement of the coupling is effected by swinging of the clamping arms  16  and  18  in a plane perpendicular to the length of the conduits. Longitudinal forces are absorbed between the coupling sections by interengagement of the arms  16  and  18  around the projecting annular flange  30  on the base/base retainer assembly  12 ,  14 , and thus do not in any way load the latches  50  or the pivot pin  32 . 
   Referring now to  FIGS. 5 through 8 , a somewhat simplified version of the coupling is illustrated. In this embodiment the base component  112  is of unitary construction comprising an annular injection molding having a bore  122  sized to closely surround the enlarged section  70  of the conduit  60 . As before the bore has at one end a chamfer  174  adapted to engage against the flared lip  72  of the conduit  60 . A tubular section  128  of the base extends between a projecting annular flange  130  at one end and a second projecting annular flange  131  at the opposite end, the flange  131  supporting a rigid mounting  133  for an axially extending pin  132  the latter being similar to the pin  32  of the previously described embodiment. 
   The pin  132  forms a pivotal mounting for a pair of clamping arms  116 ,  118  which as can be seen from  FIGS. 5A  to  5 B are mounted to be pivotable about the axis of the pin  132 . Each clamping arm  116 ,  118  is of generally semicircular C-shaped configuration and can be swung from an open position as shown in  FIG. 5B  to a closed latched position as shown in FIG.  5 C. The arm  116  thereof has an integral latch  150  resiliently supported thereon and projecting in a generally tangential direction, the arm  118  having a through hole  148  therein. The interengagement of the arms  116  and  118  is similar to that described in relation to the embodiment of  FIGS. 1  to  4  namely that as the arms are swung together about the pin  132 , the angled ramp  152  of the latch  150  engages the arm  118  at the edge of the opening  148  resiliently deflecting the latch  150  to pass through the opening  148  until the confronting diametral surfaces of the clamping arms  116 ,  118  come into engagement around the tubular section  128  and flange  130  of the base  112  at which point the tooth  154  of the latch, having passed completely through the opening  148 , is resiliently restored to overlap the edge of the arm  118  at the edge of the opening and thus lock the arms in the engaged position that is shown in FIG.  5 C. 
   Referring to FIGS.  6 , 7 A and  8 A, the coupling  110  is shown assembled onto the interengaged ends of the conduits  58  and  60 . Since the base  112  is a unitary annular structure having an inside bore  122  that is closely matched to the diameter of the widened end section  70  of the conduit  20 , it is necessary to slip the base onto the conduit  160  before the latter is end formed to produce the flared lip  72 . 
   When the conduits  58  and  60  are interengaged as before, the base member  112  is moved into position with the chamfer  174  at the end of the bore  122  seated against one side of the flared lip  72 , the opposite side of the flared lip being engaged by the annular rib  166  on the conduit  58 . With the clamping arms  116 ,  118  assembled onto the pin  132  as shown in  FIG. 5B , the arms are then swung together until they interengage as shown in  FIG. 6 , firmly securing the conduits in fluid-tight communication in a manner similar to that of the embodiment of  FIGS. 1  to  5 . 
   The configuration of the base  112  and the clamping arms  116 ,  118  and their interengagement are more clearly shown in the enlarged views of  FIGS. 7B and 8B . Particularly  FIG. 8B  shows in cross section the profiles of the clamping arms  116 ,  118  and how they form lockingly interengage with the base  112 . Thus the arms each have a grooved portion  116   a ,  118   a  which closely surround and engage the flange  130  of the base, and a cylindrically curved portion  116   b ,  118   b  which closely surround the tubular section  128  of the base member and abut axially at opposite ends against the flanges  130 ,  131  of the base member. A further portion  116   c ,  118   c  of each clamping arm closely surrounds the conduit  58 , there being an annular groove  142  partly defined in each of the arms  116 ,  118  which abuts tightly against the peripheral rib  16 . 
   Accordingly, the coupling  110  provides a secure interconnection between the conduits  58 ,  60  preventing their separation or misalignment. As with the coupling described in relation to  FIGS. 1  to  4 , in the coupling  112  forces arising as a result of pressure within the conduits does not apply any loading to the clamping arms  116 ,  118  or their interconnections in a radial or peripheral direction. Rather such forces are absorbed in the axial direction by abutment between the base  112  and the arms  116 ,  118 . The close form locking interengagement of these components ensures a tight coupling is obtained without any slackness or backlash which might ultimately lead to deterioration of the integrity of the interconnection. On the contrary, the coupling embodiments described herein can remain in place for very lengthy periods of service without loss or deterioration. Furthermore these couplings are reusable since they can be dismounted by disconnecting the latch or latches and separating the clamping arms, whereupon the conduits can be moved apart axially without further difficulty. 
   The coupling shown in  FIGS. 9A  to  9 C is a modified version of that shown in  FIGS. 5A  to  5 C and comprises a base  112  which provides a pivotal mounting for two clamping arms  116 ,  118 . As before, the clamping arm  116  carries a resiliently mounted latch  150  at the end of which is a notched tooth  154  to be received within a through opening  148  in the second pivoted arm  118 . As clearly shown in  FIGS. 9A and 9B  the arm  118  is modified by the provision of an elongate channel-shaped guard  135  which is shaped to accommodate the latch  150  so that the latter is completely shield from accidental disengagement in the fully assembled condition as seen in FIG.  9 C. Thus it will be seen that this embodiment prevents accidental disengagement of the coupling and also, shields the tooth  154  and the arm that supports it against accidental damage. Furthermore a frangible seal or the like could be included to give an indication of any unauthorized tampering or disengagement of the coupling. 
   It will be appreciated that the components of the couplings described in the foregoing can be varied widely depending upon the particular use requirements. Typically these components will be fabricated by injection molding from plastic material such as polyamide, polyurethane, and polypropylene for example. The materials could of course be strengthened and reinforced in known manner by inclusion of fibers such as carbon fibers or glass fibers. A preferred material for the coupling component is sold under the trademark Stanyl and comprises a polyamide that contains approximately 15% of glass fiber reinforcement. 
   Although specific embodiments of the invention are described in the foregoing by way of example, it will be appreciated that the invention is not restricted to the details of the disclosed embodiments, but rather extends to all embodiments falling within the ambit of the attached claims.