Abstract:
A capless filler tube closure door has a pair of spaced axles or pins which are guided by slots to initially upon being opened by a refueling nozzle move in translation away from the nozzle orifice seat and then pivot out of the way so as not to obstruct the nozzle. Upon nozzle removal as the door approaches the seat, it moves in linear translation to close on the seat to ensure uniform sealing.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to filler tubes for fuel tanks for motor vehicles and more particularly to the closure for the refueling nozzle receiving end of the filler tube or neck as it is commonly referred to.  
         [0002]     Recent mandated requirements for limiting fuel vapor emission to the atmosphere from motor vehicle fuel tanks and fuel supply systems have required an on-board diagnostic system which monitors the integrity of the fuel system at selected intervals during operation to determine if vapor leaks are present in the system. Typically, such on-board diagnostics utilize electrically controlled valves in the vapor vent lines to permit the engine air inlet or induction system to draw a slight vacuum in the system and measure the leak rate of the system as a function of the change in the vacuum over a selected time interval. Alternatively a slight positive or gage pressure may be employed to detect leakage. Currently, production motor vehicles are equipped with an on-board diagnostic system which performs such vacuum or pressure leak tests periodically during operation of the vehicle automatically without any knowledge of the vehicle operator. However, if a fault is detected in the system, an indicator for the operator is energized.  
         [0003]     In systems employing a vacuum for leak testing, in order for such on-board diagnostic systems to be effective in drawing a vacuum in the fuel system including the tank, the filler cap on the tank filler neck must be adequately sealed in order to create the vacuum in the tank. Inasmuch as fuel tank filler caps are removed and repositioned many times by the vehicle operator over the service life of the vehicle, the filler cap has proven to be a source of trouble and often leakage due to wear or improper positioning by the vehicle operator; and, thus the on-board diagnostic system will indicate a fault in the integrity of the vapor containment in the fuel system. Thus, it has been desired to eliminate the filler cap for the fuel tank filler neck and to provide a way or means for permitting the vehicle operator to engage a refueling discharge nozzle with the filler neck and to provide for automatic closure and sealing of the filler neck upon removal of the nozzle without utilizing a removable filler cap.  
         [0004]     Providing an automatic capless sealing closure for a fuel tank filler neck has proven to be a real challenge inasmuch as the closure must withstand not only the inertial loads imposed by vehicle bounce and jounce, but must also maintain the integrity of the filler neck closure seal in the event of a collision and/or vehicle rollover.  
         [0005]     Thus, it has long been desired to provide a capless closure for a vehicle fuel tank filler neck which provides for a positive seal which can be maintained during the on-board diagnostic vacuum or pressure leak test and which can be latched to ensure that the closure and seal are maintained during collision and/or rollover in a manner which is easy to install on the vehicle, user friendly for refueling operations and which is low in cost to facilitate use of the mechanism or device in high volume production.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The present invention provides a capless filler neck of the type having a nozzle-receiving aperture provided in a bulkhead on the end of the filler neck. The invention employs a closure or door with a resilient seal and is biased to seat about the nozzle aperture on the downstream side of the bulkhead. The closure or door is moveably disposed on a support structure which may be attached as a sub-assembly to the downstream side of the bulkhead and which permits the closure or door, upon operator insertion of a refueling nozzle through the aperture, to be moved a short distance in translation to remove the door seal from the seat. Upon further insertion of the nozzle, movement of the closure is guided, by engagement of following surfaces provided on the door with a set of guide surfaces on the support structure, to move pivotally out of the way to a position substantially not obstructing the aperture and permitting full insertion of the nozzle. The guide surfaces on the support structure in one embodiment comprise a pair of spaced tracks in the form of slots; and, the following surfaces on the door comprise a pair of trunnion pins or axles. Upon removal of the nozzle, the door is biased to reverse the sequence of movement and permits the seal to move against the nozzle aperture on the downstream side of the bulkhead during translation movement of the door to thereby facilitate a positive seal between the door and the aperture and eliminate scrubbing of the seal which would otherwise occur if the door were simply hinged. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a cross-section of the invention installed in the upper end of a fuel tank filler tube;  
         [0008]      FIG. 2  is an axonometric view of the closure and support mechanism subassembly of the embodiment of  FIG. 1  shown in the closed position;  
         [0009]      FIG. 3  is an axonometric view of  FIG. 2  from below;  
         [0010]      FIG. 4  is a view similar to  FIG. 2  showing the mechanism in the partially opened position;  
         [0011]      FIG. 5  is a view of  FIG. 4  from below;  
         [0012]      FIG. 6  is an axonometric view from below of the subassembly of  FIG. 4  in the fully open position;  
         [0013]      FIG. 7  is an axonometric view from above of the device in the position of  FIG. 6 ; and,  
         [0014]      FIG. 8  is a cross-section taken along section-indicating lines  8 - 8  of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Referring to  FIG. 1 , a fuel tank filler tube assembly embodying the present invention is indicated generally at  10  wherein a capless closure and support structure are indicated as a subassembly generally at  12  as received in a filler cup  14  attached to the upper end of the filler tube or neck  16 . The filler cup  14  has a bulkhead  18  secured and sealed over the open end thereof, which bulkhead has a nozzle-receiving aperture  20  formed therein.  
         [0016]     In the illustrated exemplary embodiment a closure door  22  is shown with a radially outwardly extending peripheral flange  24  formed thereon which has a plurality of apertures  28  therethrough which may be spaced circumferentially thereabout. A flexible annular seal  26  is disposed about the flange and secured thereto; as, for example, by insert molding the seal  26  thereon with portions of the molded seal material passing through the apertures  28 . The door  22  may include a one-way pressure relief valve (not shown) which opens to permit flow through central orifice  32  and peripheral slots  34 .  
         [0017]     The nozzle-receiving orifice  20  has formed thereabout an annular seating surface  36  which may have a spherical configuration, if desired.  
         [0018]     Peripheral flange  24  has formed thereon two oppositely disposed downwardly extending brackets  38 ,  40 , each of which has spaced apertures denoted respectively  42 ,  44  and  46 ,  48  which are aligned in pairs so as to have received therethrough pins or axles  50 ,  52  which extend outwardly of the brackets  38 ,  40 .  
         [0019]     Referring to  FIGS. 1 through 7 , a support structure or housing  54  is disposed on the downstream or undersurface of bulkhead  18 ; and, housing  54  may have a generally U-shaped configuration with the legs or sidewalls denoted  56 ,  58  thereof disposed in spaced generally parallel arrangement and may be formed integrally as a one-piece member. In the exemplary embodiment shown in the drawings, housing  54  has, on the closed end of the U-shape thereof, a tab or projection  60  which serves as a limit stop for movement of the door  22  as will hereinafter be described.  
         [0020]     The sidewalls  56 ,  58  each have a pair or set of spaced guide surfaces denoted respectively  62 ,  64  and  66 ,  68 . In the exemplary embodiment illustrated in the drawings, the guide surfaces comprise pairs of slots configured to provide the desired movement of the door  22  when the ends of pins  50 ,  52  are received in contact with the guide surfaces such as the slots. It will be understood that although slots are shown in the illustrated embodiment, alternatively, guide tracks similarly configured may be used. In the presently illustrated embodiment, the ends of the pins  50 ,  52  act as followers or trunnions to be guided by the slots  62 ,  64 , and  66 ,  68 . The pins may be retained in any suitable manner, as for example, be end caps pressed thereon as denoted by reference numerals  70 ,  72  and  74 ,  76 , and which caps may have a hat-shaped configuration for retaining the pins axially.  
         [0021]     A torsion spring having spaced coils  78 ,  80  has one end of each interconnected in a U-shaped portion  82  (see  FIGS. 1, 5 ,  6  and  8 ) which is retained on the housing by a suitable tab  85  which may be integrally formed therewith. The opposite ends of the coils  78 ,  80  extend outwardly of the coils and over the sidewalls  56 ,  58 , as denoted by reference numerals  84 ,  86 , and bear against the undersurface of pin  50  to provide a spring bias in a direction to close the door  22  against the seating surface  36 .  
         [0022]     In operation, when the end of a refueling nozzle show in dashed outline and denoted by reference numeral  90  is placed in contact with the upper surface or door  22 , and pushed downwardly by the operator to enter the aperture  20 , the door  22  initially undergoes movement in translation to the position shown in dashed outline in  FIG. 1 . The pins  50 ,  52  thus move in the vertically oriented left end portion of the slots  62 ,  64  and  66 ,  68 . As the nozzle is further inserted into the aperture  20 , the door  22  is moved downwardly; and, the followers  50 ,  52  enter into a curved portion of slots  62 ,  64  and  66 ,  68  which causes the door to rotate to the position shown in  FIGS. 4 and 5 . Further insertion of a refueling nozzle causes the followers  50 ,  52  to move in the guide surfaces or slots until the door is vertically positioned to the side of the aperture  20  so as to substantially not obstruct the aperture. In this regard, it will be noted that the guide surfaces  62 ,  64  and  66 ,  68  extend transversely with respect to the axis of the tube  16  to allow the door  22  to move transversely in the final stage of movement to the fully opened position shown in  FIGS. 6 and 7 . In other words, the guide slots extend transversely to one side of the aperture  20  to permit the door to move out of the way of the aperture in the fully opened position.  
         [0023]     Upon removal of a refueling nozzle the door reverses the sequence of movement; and, as the door approaches the closed position, as represented by the dashed line in  FIG. 1 , the door is again parallel to the bulkhead and closes the seal  26  against the seating surface  36  in a linear translation movement which prevents scrubbing and/or undue compression of one side of the seal as would be the case if the door were pivoted about a simple hinge. Thus, the configuration of the guide surfaces and movement of the followers of the present invention provide for assured uniform seating and allows seal to wipe orifice surface  36  and compression of the seal on the seating surface; and, by eliminating scrubbing of the seal on the seating surface during opening and closing provides for improved service life of the seal.  
         [0024]     Although the invention has hereinabove been described with respect to the illustrated embodiments, it will be understood that the invention is capable of modification and variation and is limited only by the following claims.