Abstract:
A method and apparatus for assembling a fluid conduit assembly and testing the fluid conduit for leaks. Clipping devices support fasteners at a position remote from the conduit. According to the invention the fasteners can be loaded into clip nests provided by the clipping devices while leak testing of the conduit is performed. The performance of these steps simultaneously effectively eliminates the conventional requirement of pre-loading installation fasteners into the leak testing apparatus, and thus reduces the overall time required for the testing and assembly of fluid conduits by approximately one third. If the leak test is successful, all of the fasteners are then moved to the conduits and closed to integrate the conduit assembly.

Description:
FIELD OF THE INVENTION 
   The present invention relates to production methods and apparatus. In particular, this invention relates to a method and apparatus for assembling a fluid conduit assembly and testing the fluid conduit for leaks. 
   BACKGROUND OF THE INVENTION 
   Rigid fluid conduits for automobiles, such as brake lines and fuel lines, typically must be bent and configured to fit along the undercarriage of an automobile. Such conduits function hydraulically, and must be tested for leaks before being installed, particularly in the case of brake and fuel systems where failure of the system during use could be catastrophic to the driver of the automobile. 
   In the case of fuel lines for example, a conventional leak testing apparatus provides a series of supports positioned to suspend the pre-configured fuel tubes at predetermined intervals during leak testing. Clips or brackets for fixing the tubes together to create an integrated fuel line assembly are placed by hand on the conduit supports in the leak testing apparatus. The clips or brackets also provide a post or other structure for affixing the conduits to the undercarriage of the automobile. Hereinafter the term “clips” is used to denote closeable clips, brackets and other such fasteners that are used for affixing components such as fuel lines together and/or to an automobile. 
   The conduits are then positioned in the open clips for leak testing. To test for leaks the conduits are pressurized by an air compressor, and any detected decrease in pressure will indicate a leak in the conduit. If a leak is detected, one or both of the conduits must be replaced. If there is no leak, the installation clips are closed to secure the conduits together and the fuel line assembly is removed from the leak testing device and ready to install in an automobile. 
   However, leak testing is a very delicate and sensitive process, and the fluid conduits must be suspended in a secure and completely motionless position in order to ensure that the results of the leak test are accurate. Accordingly, the tubes are suspended in the leak testing apparatus with the installation clips already installed, so that the clips are ready to be closed when the leak test is complete, to avoid any movement of the tubes during leak testing. 
   The conventional leak testing/tube clipping procedure thus requires time to load the clips; additional time to load the tubes into the open clips; additional time to conduct the leak test; and additional time to close the clips and unload the tube assembly. Due to the sensitive nature of the leak test, the clips cannot be loaded while leak testing is taking place. 
   SUMMARY OF THE INVENTION 
   The present invention significantly reduces the time required for the leak testing/tube assembling procedure. According to a preferred embodiment of the invention, at selected intervals along the conduit the leak testing apparatus provides clipping devices which support the clip at a position remote from the conduit. Whereas in prior art systems clips must be loaded into the leak testing apparatus before the conduits are suspended for testing, according to the invention the clips can be loaded into clip nests provided by the clipping devices while leak testing is taking place. If the leak test is successful, all of the clips are then moved to the conduits and closed simultaneously, and the tested tube assembly is then unloaded from the leak testing apparatus. 
   The invention thus provides a device for the automation of clip placement and closure, which allows the step of leak testing to be carried out at the same time as the loading of installation clips into the automated clipping devices. The performance of these steps simultaneously effectively eliminates the conventional requirement of pre-loading installation clips into the leak testing apparatus, and thus reduces the overall time required for the testing and assembly of fluid conduits by approximately one third, thereby substantially increasing the rate of production and commensurately reducing production costs. 
   The present invention thus provides a method of assembling and testing at least one fluid conduit, comprising the steps of: a. suspending the conduit from a plurality of supports; b. pressurizing the conduit and monitoring a pressure within the conduit for a preset interval to test for leaks; c. during step b., loading a closeable fastener to each of a plurality of clip nests respectively supporting the fastener at a first position remote from the conduit; d. after the leak test is complete, moving the fasteners to a second position adjacent to the conduit; and e. closing the fasteners. 
   The present invention further provides a clipping device for applying a fastener to a conduit, comprising a clip nest supported at a position remote from the conduit, an actuator for moving the clip nest toward the conduit, and a conduit clamp for clamping the conduit, actuated by moving the clip nest toward the conduit, whereby when a fastener is disposed in the clip nest and the clip nest is moved to a position where the fastener is adjacent to the conduit, the clamp bears against the conduit to hold the conduit in the fastener. 
   The present invention further provides an apparatus for assembling a fluid conduit assembly and testing the conduit for leaks, comprising a plurality of supports for suspending the conduit at preset intervals; a leak tester comprising a compressor for pressurizing the conduit to test for leaks; a plurality of clip nests for respectively supporting a plurality of fasteners at a first position remote from the conduit; and an actuator for moving the fasteners to a second position adjacent to the conduit. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In drawings which illustrate by way of example only a preferred embodiment of the invention, 
       FIG. 1  is a schematic elevational view of a leak testing apparatus according to the invention, 
       FIG. 2  is a perspective view of a preferred embodiment of a clipping device for the apparatus of the invention, taken from above and one side. 
       FIG. 3  is a perspective view of the embodiment of  FIG. 2  taken from the same side and below. 
       FIGS. 4A to 4C  are schematic side elevations of the embodiment of  FIG. 2  respectively showing the device infully retracted, partially elevated and fully elevated positions. 
       FIG. 5  is a side elevation of the embodiment of  FIG. 2  in a fully retracted position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates a leak testing apparatus  10  according to the invention. It will be appreciated that the leak testing apparatus  10  can be used for testing for leaks in any kind of conduit, it being advantageously used for pressure-testing automotive conduits such as fuel lines  2 . It will be further appreciated that although the leak testing apparatus of the invention may be used to assemble and test a plurality of conduits  2 , it is also useful for testing and assembling mounting clips to a single conduit. 
   The leak testing apparatus  10  conventionally comprises an open housing  12  with a floor  14  and a series of tube supports  16  positioned along a path conforming to the configuration of the tubes  2 , suspending the tubes  2  at a sufficient number of positions to ensure a stable, motionless support for the tubes  2  during the leak testing process. In a conventional leak testing apparatus clips  4  are loaded onto the supports  16  prior to loading the tubes  2  into the leak testing apparatus. The closeable fasteners, for example clips or brackets  4  will be closed once the leak test is successfully completed, to fix the tubes  2  into an integrated tube assembly and to provide a means (for example a post  4   a ) for mounting the tube assembly to an automobile (not shown). The invention will be described with reference to the clips  4  illustrated, however it will be appreciated that the invention can be applied equally to conduits secured by clips, brackets or any other suitable fasteners. 
   According to the invention, the supports  16  are configured with tube nests, which support the tubes  2  directly, i.e. without first loading clips  4 . The clips  4  are instead loaded onto a plurality of clipping devices  30  which support the clips  4  in a position remote from the tubes  2  until the leak test has been successfully completed, at which point the clips  4  are positioned against the tubes  2  and closed to complete the tube assembly. The leak testing apparatus  10  of  FIG. 1  is thus used to perform a preferred embodiment of the method of the invention, which is as follows: 
   a. suspending at least one conduit  2  from a plurality of supports  16  in a leak testing apparatus  10 ; 
   b. pressurizing the conduit  2  and monitoring a pressure within the conduit  2  for a preset interval to test for leaks, 
   c. during step b. loading a clip  4  to each of a plurality of clip nests  40  respectively supporting the clips  4  at a first position remote from the conduit  2 ; 
   d. after the leak test is complete, moving the clips  4  to a second position adjacent to the conduit  2 ; and 
   e. closing the clips  4 . 
   The step of moving the clips  4  to a second position adjacent to the conduit  2  is preferably performed by a clipping device  30  which automatically applies the clips  4  to the tubes  2 , and preferably closes the clips  4  as well.  FIGS. 2 to 5  illustrate a preferred embodiment of a clipping device  30  for automating the method of the invention in the leak testing apparatus  10  illustrated in  FIG. 1 . 
   The clipping device  30  comprises a base  32  supporting a movable clip nest  40 , for example comprising a block  41  having a removable insert  43  with a depression  42  configured to hold the clip  4  in a stable upright orientation. The clip  4  shown in the drawings by way of example comprises a post  4   a  for mounting the clip  4  (and thus the tube assembly) to the undercarriage of an automobile, and the clip nest  40  advantageously has a bottom opening  42   a  for receiving the post  4   a , shown in  FIG. 4 , which helps to keep the clip  4  in position after loading. However, by forming the insert  43  separately from the block  41 , the clip nest  40  can be readily adapted to different clips merely by replacing the clip insert  43  with an insert of a different configuration adapted to support a different style of clip. 
   The clip nest  40  is supported on a movable platform  50 , which is elevated and retracted by a primary actuator. It will be appreciated that this can be any actuator, however in the preferred embodiment this is advantageously a pneumatic actuator since the leak testing apparatus  10  already provides an air compressor  6 . In the embodiment shown the primary actuator comprises a pair of pneumatic pistons  52  extending from pneumatic cylinders  54  formed in the base  32  (shown in  FIG. 4B ). The platform  50  is thus extended from the retracted position shown in  FIG. 4A  to an elevated position as shown in  FIG. 4B  by pressurizing the cylinders  54 , for example through air port  56 , and lowered back to the retracted position under the influence of gravity when the air pressure is released. Although a single piston  52  would be sufficient to elevate the platform  50  to the required level, a pair of pistons  52  is preferred in order to maintain precise alignment between the base  32  and the moving platform  50 . 
   The clip nest  40  thus begins the leak test cycle in the position shown in  FIG. 4A , remote from the tubes  2 , allowing the operator to load clips  4  into the clip nest  40  after the conduits  2  have been affixed to the supports and while the leak test is being performed. After the leak test is successful, the clip nest  40  is raised to a second position, shown in  FIG. 4B , at which the clip  4  is held adjacent to the tubes  2 , as will be described in greater detail below. 
   A tube clamp  70 , best seen in  FIG. 2 , is provided to clamp the tubes  2  against the clip  4  when the clip nest  40  is raised to the elevated position. In the embodiment shown a clamp arm  72  is pivotally mounted to the base  32 , for example at mounting block  78 , and provided with a slot  72   a  (best seen in  FIG. 2 ) through which a pin or cam  74  is disposed. A brace arm  76  is fixed to the clamp arm  72 . The cam  74  is fixed relative to the platform  50 , as by cam arm  74   a . The brace arm  76  thus pivots between a neutral position removed from the conduits  2  and a clamping position at which the brace  76  holds the tubes  2  against the clip  4 . Elevation of the platform  50  thus causes the cam  74  to travel up the slot  72   a , which is configured and oriented to draw the clamp arm  72  toward the base  32  and thus to draw the brace  76  down onto the tubes  2 . The tubes  2  are clamped against the clip  4  as the clip nest  40  reaches the elevated position, as shown in  FIG. 4B . 
   In the preferred embodiment the clipping device  30  also provides means for closing the clip  4  after the clip nest  40  has been raised to the elevated position. For this purpose the clip nest  40  is mounted to the platform  50  by a secondary actuator, in the preferred embodiment comprising a pneumatic cylinder  60  affixed to the platform  50  and driving a piston  62  affixed to the clip nest  40 . preferably a pair of guide rods  64  is provided to maintain alignment between the clip nest  40  and the platform  50  as the secondary actuator is extended and retracted. 
   A clip closer  80  comprises a closer arm  82  pivotally mounted to the base  32 , conveniently to mounting block  78 , and provided with respective radial and transverse slot sections  82   a ,  82   b  (best seen in  FIG. 3 ) through which the cam  74  is disposed. A roller arm  84  is fixed to the closer arm  82  and supports a roller  86  on its free end. The roller  86  thus pivots between a neutral position removed from the clip  4  and a closing position at which the roller  86  rolls along the top portion  4   b  of the clip  4  and presses the top portion  4   b  onto the body  4   c  of the clip to permanently close the clip  4 . 
   The clip closer  80  is not actuated until the conduits  2  are clamped firmly in place within the clip body  4   b . Elevation of the platform  50  causes the cam  74  to travel along the radial slot section  82   a , which is already oriented generally in the direction of motion of the cam  74  and this motion therefore does not move the closer arm  82  even while the brace  76  is being drawn toward the clip  4 , as shown in  FIG. 4B . 
   To close the clip  4 , the platform  50  is further elevated by the primary actuator, and at the same time the clip nest  40  is lowered by retracting the secondary actuator, which thus moves in opposition to the platform  50  to maintain the clip  4  in a stationary position adjacent to the conduits  2 . During this interval the cam  74  travels along the transverse slot section  82   b , which draws the roller arm  86  sharply toward the clip  4  to close the top  4   b  of the clip  4 , as shown in  FIG. 4C . 
   In operation, a leak testing apparatus  10  such as that illustrated in  FIG. 1  is equipped with a plurality of clipping devices  30 , one at each position where a clip  4  is desired, and a plurality of tube supports  16 , positioned so as not to interfere with the clipping devices  30 . A pneumatic hose  6   b  from a local air compressor  6  is coupled to the primary and secondary actuators of each clipping device  30 . The conduits  2  are affixed to the supports  16 , and a pneumatic hose  6   a  from the air compressor  6  is coupled to the ends of the tubes  2  in conventional fashion, as shown in  FIG. 1 , in preparation for the leak test. 
   The clipping devices  30  start in the position shown in  FIG. 4A , with the primary actuator fully retracted and the secondary actuator fully extended. The clamp  70  and closer  80  are in the neutral position, with the brace  74  and roller  86  spaced well away from the tubes  2  and clip  4 , respectively. 
   The tubes  2  are pressurized to perform the leak test. As the leak test is being performed the operator loads a clip  4  into the clip nest  40  of each clipping device  30 , oriented such that the top portion  4   a  faces the closer  80 . The top portion  4   a  of each clip  4  is left fully open. 
   Upon completion of the leak test, if the test indicates that a tube  2  has a leak, the leaking tube  2  is replaced and the test is performed again. If the test indicates that the tubes  2  are free of leaks, the operator actuates the primary actuator to elevate the platform  50 . The secondary actuator is not actuated at this stage, so the clip nest  40  remains fixed in position relative to the platform  50 . As the pistons  52  extend the platform  50  and clip nest  40  are elevated, and the cam  74  travels along the slots  72   a  and  82   a . The closer arm  82  remains stationary, but the cam  74  travelling along the slot  72   a  draws the clamp arm  72  toward the base  32 , and thus draws the brace  74  tightly down onto the tubes  2  to clamp the tubes  2  against the clip  4 , as shown in  FIG. 4B . 
   To close the clip  4 , the primary actuator is actuated to further elevate the platform  50  while the secondary actuator is actuated to retract the piston  62  into the cylinder  60 , and thus lower clip nest  40  toward the platform  50  as the platform  50  rises. The net result is that the clip nest  40  remains stationary at the level of the tubes  2  while the cam  74  travels into the transverse slot  82   b , which draws the roller arm  86  sharply toward the clip  4 , as shown in  FIG. 4C . The roller  86  rolls along the top  4   b  of the clip  4 , pressing the top  4   a  against the clip body  4   b  and lodging one or more barb-shaped projections into one or more openings, as is well known, to permanently close the clip  4  over the tubes  2 . The clamp arm  72  is provided with a short radial slot section  72   b , seen in  FIG. 2 , which allows the cam  74  to travel through the clip closing stage without affecting the position of the clamp  80 . 
   With all clips  4  closed in this fashion, the secondary actuator is extended and the primary actuator is retracted, to return the platform  50  and clip nest  40  to the neutral position. The cam  74  travelling back along the slot  82   b  returns the closer  80  to the neutral position, and with further retraction of the primary actuator the cam  74  travelling back along the slot  72   a  returns the clamp  70  to the neutral position to release the tube assembly from the clipping devices  30 . The supports  16  are unlatched and the tube assembly is removed from the leak testing apparatus  10 . The next set of tubes  2  is positioned in the supports  16 , and the process is repeated. 
   It will be appreciated that making the clip nest  40  movable relative to the platform  50 , and providing the secondary actuator to move the clip nest  40  relative to the platform  50 , is for the sole purpose of closing the clip  4 . The aspects of the invention which allow the clips  4  to be loaded while the leak test is being performed, by providing a clip nest  40  in a first position remote from the tubes, and after the leak test is complete moving the clips  4  into position against the tubes  2 , operate equally well whether or not the automatic clip closing system is provided. 
   Also, while the drawings illustrate a preferred embodiment in which the tubes  2  are supported above the clipping devices  30 , and thus the operation of the clipping devices  30  is substantially in a vertical direction, it will be appreciated that since the tubes  2  are held firmly in place by the supports  16  during the operation of the leak testing apparatus  10 , it is not necessary that the “floor”  14  of the leak testing apparatus be at the bottom. The supports  16  and clipping devices  30  can be oriented in any desired fashion, as long as the clips  4  do not dislodge from the clip nests  40  under the influence of gravity. 
   Various embodiments of the present invention having been thus described in detail by way of example, it will be apparent to those skilled in the art that variations and modifications may be made without departing from the invention. The invention includes all such variations and modifications as fall within the scope of the appended claims.