Abstract:
A duct connection assembly suited to connect a thermoplastic fluid duct to a metal intake port. A connector housing is affixed to the end of the fluid duct and functions to releasable seal the fluid duct onto the intake port using an annular projection around the end of the port. When the port is inserted into the connector housing a snap lock connection is provided by a plurality of locking teeth that project inwardly through the housing from a collar to engage with the annular projection. Quick disconnect of the port from the fluid duct is effected by rotation of the collar with respect to the connector housing so that cam surfaces on the housing interact with the locking teeth to move the teeth radially outward to disengage from the annular projection.

Description:
TECHNICAL FIELD 
   This invention relates generally to fluid ducts and, more particularly, to the releasable, sealed joining together of fluid duct members. 
   BACKGROUND INFORMATION 
   Air flow is routed using tubular duct assemblies. The duet assemblies must be structurally robust to withstand the temperatures, vibrations, and fluid flow pressures to which they can be expected to encounter. In a typical automotive application, a duct assembly should tolerate sustained, continuous temperatures of 250° F. and higher and pressures of 30 pounds per square inch or more. 
   In the past, such duct assemblies have been constructed with a steel tube body with silicone and rubber end connectors, in order to withstand these pressures and temperatures. Typically for a conventional duct assembly, the end connectors are assembled with four band clamps and two hoses. These hose-and-clamp end connections prevent the pressurized fluid in the duct from bleeding out of the assembly along leak paths. 
   It has been proposed to form a duct assembly with a thermoplastic tube body and metal wire circumferential connections. For details, refer to patent publication no, US 2006/0022460 (publication of application Ser. No. 10/902,685, filed Jul. 29, 2004). 
   While previous duct assembly designs have been satisfactory, there remains room in the art for improvement. Reduction of weight and cost without loss of function is important to the advancement of automotive technology. Additionally, decreasing packaging, complexity and cost without sacrificing performance would also be desirable. Furthermore, functionality could be improved if the number of potential leak paths in the duct work can be reduced. 
   SUMMARY OF THE INVENTION 
   It is an advantage of the present invention to provide a duct assembly having a reduced cost of construction, reduced weight, fewer leak paths, a simple installation, and ease of recycling. 
   It is another advantage of the present invention to provide a duct assembly that is smaller and thus provides advantages in packaging. It is a further advantage of the present invention to provide a duct assembly that has fewer parts and thus has complexity. 
   In general terms, the present invention provides a duct assembly connector having a collar that defines a bore and has inwardly directed teeth such that the teeth engage an annular projection around a sleeve that fits inside the collar. The teeth are selectably retractable so that the sleeve can be disengaged from the collar. Retraction of the teeth is effected by rotation of a locking ring about the collar. 
   One aspect of the duct connector is that it is lightweight. That is because the structure for engaging the collar with the sleeve is formed as a single piece rather than as multiple pieces. 
   Another aspect of the duct connector is that it is not costly to manufacture. That is because the number of parts is minimized. 
   Yet another aspect of the duct connector is that it is more reliable. That is because the number of parts is minimized, thus decreasing the odds of any one part failing at a given time. 
   These and other features and advantages of this invention will become more apparent to those skilled in the art from the detailed description of a preferred embodiment. The drawings that accompany the detailed description are described below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a perspective view of an embodiment of the connector with the connector and fluid port locked together and with duct members shown in phantom in accordance with one embodiment of the present invention. 
       FIG. 2  shows a perspective view of an embodiment of the connector with the connector and fluid port separated and with duct members shown in phantom in accordance with one embodiment of the present invention. 
       FIG. 3  shows an exploded view of an embodiment of the connector structures in accordance with one embodiment of the present invention. 
       FIG. 4  shows a plan view of an embodiment of the connection assembly with the collar in a rest position in accordance with one embodiment of the present invention. 
       FIG. 5  shows a detail section view of the connection assembly of  FIG. 4 , with a locking tooth engaging the fluid port. 
       FIG. 6  shows a plan view of an embodiment of the connection assembly with the collar in a forced position in accordance with one embodiment of the present invention. 
       FIG. 7  shows a detail section view of the connection assembly of  FIG. 6 , with a locking tooth disengaged from the fluid port. 
       FIG. 8  shows a detail section view of the seal between the connector housing and the fluid port in accordance with one embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , the connection assembly  100  is shown in perspective with the connector  200  and the fluid port  300  locked together. The opposed duct members  2 ,  3  to which the connection assembly  100  is to be fixed are shown in phantom. In  FIG. 2 , the connection assembly  100  is shown in perspective with the connector  200  and the fluid port  300  separated. An annular projection  310  is visible in  FIG. 2  encircling the exterior surface of the fluid port  300 . The opposed duct members  2 ,  3  are again shown in phantom. 
   The disclosed connector assembly  100  is well suited to the situation where fluid ducts of differing materials need to be joined together, but is not limited to such an interface. The connector assembly may be embodied to accommodate the situation where the fluid port is an open end of a metal duct and the connector is fixed to an end of another metal duct. The connector assembly may also be embodied to accommodate situations where the fluid port is an open end of a plastic duct and the connector is fixed to an end of a metal duct. Another situation for which the connector assembly may be embodied is where the fluid port is an open end of a metal duct and the connector is fixed to an end of plastic duct. Also, the connector assembly may be embodied to accommodate the situation where the fluid port is an open end of a plastic duct and the connector is fixed to an end of a plastic duct. 
   According to one embodiment the fluid port is a metal throttle body port and the connector is fixedly joined to an end of a plastic duct. When the connector and the duct to which it is fixedly joined are both formed of thermoplastic, they may be joined by welding, gluing, or may be formed together as an integral and unitary single piece (such as by injection molding or by hydroforming). According to another embodiment, the fluid port is a metal throttle body port and the connector is fixedly joined to an end of a metal duct. 
   Referring to  FIG. 3 , an exploded view shows the components of the connector  200 . A seal  210  fits inside a connector housing  220 . In one embodiment, the seal  210  is disposed in an undercut or groove  222  formed in an inner surface of the housing  220 . The seal  210  preferably press fit into the undercut or groove  222 . A retainer  230  is then disposed into the connector housing  230  thickness at its front-facing side  212 . 
   The connector housing  220  is substantially cylindrical and hollow and is internally counter bored to have two undercut surfaces. The first undercut surface  222  is sized to hold the seal  210  in press fit engagement. The second surface  224  is an undercut surface that is sized to hinder axial progress of the fluid port  300  (see  FIG. 2 ) through the housing  220 . Radially spaced around the outer periphery of the housing  220  are plural housing slots  226 . Each of the housing slots  226  is immediately adjacent one of plural cam surfaces  228 . 
   The retainer  230  has a chamfer  232  at its front inside edge to ease insertion of the fluid port  300  into the connector  200 . Radially spaced around the outer periphery of the retainer  230  are plural retainer slots  234 . Each of the retainer slots  234  is disposed so as to align with a respective one of the housing slots  226  when the retainer  230  is disposed inside the housing  220 . 
   An annular collar  240  is sized to fit around the outside of the housing  220  and has plural inwardly biased locking members  242 . Each of the locking members  242  has a locking tooth  244  at its free end and each of the locking teeth  244  are sized to extend through a respective one of the plural housing slots  226  and a respective one of the plural retainer slots  234 . The inner surface  246  of each of the locking members  242  engages a respective one of the cam surfaces  228  on the outside of the housing  220 . The locking teeth  244  are each beveled on one side only to facilitate the teeth  244  sliding over the annular projection  310  while being displaced outwardly when the port  300  is inserted into the connector  200 . 
   When installed about the housing  220  with its locking teeth  244  extending through the housing slots  226  and into the retainer slots  234 , the collar is free to rotate about the housing  220  between two extreme positions, lock and unlock. Referring to  FIG. 4 , an embodiment of the connection assembly  100  is illustrated in a plan view with the collar  240  in a lock position. The collar  240  is placed in the lock position by rotating it in the direction the locking members  242  point until the free ends  442  of the locking members  242  are in contact with the visible ends  426  of the housing slots  226 . 
   The lock position allows each locking tooth  244  to be pushed by the spring bias of the locking member  242  inward through the housing slot  226  and the retainer slot  234  and project into the interior cavity of the connector  200 . This is shown in the detail section view of  FIG. 5 , which is taken along the section line labeled V-V in  FIG. 4 . By projecting into the interior cavity of the connector  200 , the locking tooth  244  can engage the fluid port  300  at the annular projection  310 . In this way, the connector  200  is locked to the fluid port  300 . 
   Referring to  FIG. 6 , a plan view of the connection assembly  100  is illustrated with the collar  240  in the unlock position. The collar  240  is placed in the unlock position by rotating it in the direction opposite how the locking members  242  point until the locking tooth  244  contacts the hidden end  626  of the housing slot (see  FIG. 7 ). In the unlock position of the collar  240 , there is a pronounced gap  630  between the free end  442  of the locking member  242  and the visible end  426  of the housing slot  226 . 
   In the unlock position, each cam surface  228  engages the inner surface  246  (see  FIG. 3 ) of the corresponding locking member  242  so as to move each locking member  242  outward against its bias. When locking members  242  have been moved outwards by rotation of the collar  240  into the unlock position, each locking tooth  244  is likewise caused to move outward so that the teeth  244  extend inward only through the housing slot  226  and into the retainer slot  234 , without projecting into the interior cavity of the connector  200 . This is shown in the detail section view of  FIG. 7 , which is taken along the section line labeled VII-VII in  FIG. 6 . Because the locking teeth  244  have been moved outward and do not extend into the interior cavity of the connector  200 , the teeth  244  are disengaged from the annular projection  310  of the fluid port  300 . 
   One aspect of the connector  100  is that it provides for a sealing connection that prevents leaks. Referring to  FIG. 8 , a detail section view of the connector (taken at the detail line VIII shown in  FIG. 7 ) shows the seal  210 . The seal  210  is retained in place in the undercut surface  222 . The seal  210  can also be compressed between the connector housing  220  and the fluid port  300 . 
   In another embodiment, the rear-facing side  214  of the seal  210  has an internal void  216  to enable the seal  210  to compress readily between the connector housing  220  and the fluid port  300 , and to provide a secure seal despite differences in how the connector housing  220  and the fluid port  300  may expand and contract with changes in temperature. It is noted that this exemplary seal is not the only type of seal that may be used to practice the invention and that seals having diverse cross-sections (e.g., O-rings) may be successfully be used. 
   To sealingly lock the fluid port  300  to the duct  2  and its connector  200 , the end of the fluid port  300  is inserted into the connector  200  with the collar in the lock position. The outer diameter of the fluid port  300  matches the inner diameter of the seal  210 . The annular projection  310  of the port  300  engages the locking teeth  244  of the inwardly biased locking members  242 , urging the teeth  244  to move radially outward. The teeth  244  then snap inwardly into place behind the annular projection  310  and secure the fluid port  300  to the duct  2 . The seal  210  is sealed to the port  300  and prevents leakage through the connector assembly  100 . 
   According to one embodiment, the duct  2 , the housing  220 , the retainer  230 , and the collar  240  are all constructed from a thermoplastic material. One example of a suitable material is non-filled Nylon 6, formed using a suction blow molding. During the suction blow molding process, a molten thermoplastic material is sucked into a closed mold by a vacuum created by a suction fan. Once the molten thermoplastic material has reached its final position, air is blown into the mold, forcing the thermoplastic material against the sides of the mold. After cooling, the part is removed. It is to be understood, however, that the duct  2 , the housing  220 , the retainer  230 , and the collar  240  may alternatively be constructed from various other materials using a variety of different processes. 
   The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of the invention. Accordingly, the scope of legal protection afforded this invention can only be determined by studying the following claims.