Abstract:
A fuel cap has an upper housing and a lower housing, each configured to be inserted into the filler neck of a vehicle fuel system. The upper housing and lower housing are cooperatively configured to allow both rotational and axial relative movement with respect to one another. A seal coupled to the lower housing sealingly engages the filler neck when the fuel cap is in a tightened position. A spring mount is coupled to the lower housing and engages a spring that is positioned to bias the lower housing axially toward the upper housing to assist in loosening contact of the seal and filler neck during removal of the fuel cap. The fuel cap further has a drive axially spacing the upper housing from the lower housing as the upper housing rotates relative to the lower housing. A cam and cam follower connection between the upper and lower housing provides the drive. At least one lug extends from the lower housing to engage a respective notch formed on the interior surface of the filler neck and the lugs and notch cooperate to prevent rotation of the lower housing relative to the filler neck when the cap is in the tightened position.

Description:
This application claims priority under 35 USC 119(e) based upon United States Provisional Application No. 60/153,420 filed on Sep. 10, 1999, which disclosure is incorporated by reference herein. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to fuel tank closures. More particularly, the present invention relates to a fuel tank closure having a housing assembly and a seal coupled to the housing assembly. The seal is positioned to engage a tank filler neck to provide a sealed closure of the tank filler neck. 
     A fuel cap for a filler neck a vehicle fuel system includes an upper housing and a lower housing configured to be inserted into the filler neck. The upper housing and lower housing are cooperatively configured to allow both rotational and axial relative movement with respect to one another. 
     A seal is positioned to lie between the lower housing and the filler neck, thereby creating a seal when the fuel cap is moved to a tightened position. A spring mount is coupled to the lower housing. A spring, preferably a compression spring, engages both the spring mount and the upper housing to bias the lower housing axially toward the upper housing. This bias assists in loosening contact of the seal and filler neck during removal of the fuel cap. 
     In preferred embodiments, a cam and cam follower connection is provided between the upper and lower housing. The cam and cam follower connection includes at least one cam arranged on an upper surface of the lower housing and positioned on the upper surface so that the cam slopes upward toward the upper surface to engage a cam follower depending from a lower flange of the upper housing. In other embodiments, these locations may be reversed: the cam may be configured on the upper housing and the cam follower may be configured on the lower housing. In either embodiment, the cam and cam follower cooperate to generate relative axial movement as the upper housing is rotated relative to the lower housing. 
     Each cam includes a wall at a lower end of the cam and a detent formed adjacent an upper end and configured to receive a lower end of the cam follower. 
     The cap includes at least one lug extending radially outwardly from the outer surface of the lower housing. Each lug engages a respective notch in the filler neck when the cap is moved to the tightened position to prevent rotation of the lower housing relative the filler neck when the cap is in the tightened position. 
     Additional features of the invention will become apparent to those of ordinary skill in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The detailed description particularly refers to the accompanying figures in which: 
     FIG. 1 is an exploded assembly view of a fuel tank closure positioned above a filler neck; 
     FIG. 2 is a side elevation view of the fuel tank closure of FIG. 1 showing the fuel tank closure assembled and in a position prior to installation; 
     FIG. 3 is a side elevation view similar to FIG. 2 showing the fuel tank closure in an installed position within the filler neck; and 
     FIG. 4 is a side elevation view of a fuel tank closure according to an alternative embodiment showing the closure positioned in a fuel tank filler neck and biased against the filler neck by a compression spring. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A fuel tank closure  10  in accordance with the present disclosure is shown in FIG.  1 . Closure  10  is movable relative to a fuel tank filler neck  12  between a disengaged position, as shown in FIG. 2, and an installed position as shown in FIG.  3 . Closure  10  includes a housing assembly  14  and a seal  16  coupled to housing assembly  14 . While closure  10  is in the installed position, seal  16  engages filler neck  12  and cooperates with housing assembly  14  to substantially seal filler neck  12 . 
     While seal  16  is engaged with filler neck  12 , fuel (not shown) in communication with filler neck  12  can cause seal  16  to swell. This swelling increases the compression force between seal  16  and filler neck  12 . This increased force creates more resistance to removal of seal  16  from filler neck  12  making closure  10  more difficult to remove from filler neck  12 . 
     To aid in removal of seal  16  from filler neck  12 , seal  16  is axially biased outwardly to provide a force that assists in pulling seal  16  from filler neck  12 . Closure  10  includes an ejector spring  24  that provides this force. Ejector spring  24  stores energy during installation of closure  10  in filler neck  12 . During removal of closure  10 , this stored energy is released to aid in pulling seal  16  from filler neck  12 . Ejector spring  24  could be any force generator configured to provide the seal pulling force described herein and is a compression spring in the illustrated embodiment. 
     Housing assembly  14  includes an upper housing  18  that receives ejector spring  24  and a lower housing  20  that carriers seal  16 . Closure  10  further includes a spring retainer or mount  22  positioned within upper housing or upper body  18  and coupled to lower housing or lower body  20 . Spring  24  is positioned between spring mount  22  and upper housing  18 . 
     Spring mount  22  couples lower housing  20  to upper housing  18  so that lower housing  20  can move axially relative to upper housing  18  as shown, for example, in FIGS. 2 and 3. While in the disengaged position, lower housing  20  is positioned to lie adjacent to upper housing  18  as shown in FIG.  2 . While in the engaged position, lower housing  20  is spaced apart from upper housing  18  as shown in FIG.  3 . 
     Spring  24  biases lower housing  20  toward upper housing  18  through spring mount  22 . As lower housing  20  moves away from upper housing  18 , spring  24  is compressed so that the biasing force provided by spring  24  increases. As previously mentioned, this additional biasing force aids in pulling seal  16  and lower housing  20  out off engagement with filler neck  12 . 
     Upper housing  18  includes a cylindrical body  26  and an upper flange  28  coupled to cylindrical body  26 . A handle  13  is coupled to upper flange  28  of upper housing  18  for a user to grip and turn upper housing  18 . A suitable handle is disclosed in PCT Patent Application Ser. No. PCT/US98/00863 to Jeffery Griffin and titled Quick-On Filler Neck Cap which is expressly incorporated by reference herein. Other handle configurations may also be used including handles having lost motion and/or breakaway features. 
     Upper flange  28  includes a plurality of flexible arms  30  having pawl teeth  32  providing a torque-override feature between the handle  13  and upper housing  18 . Additional description of the torque-override feature is disclosed in PCT Patent Application Serial No. PCT/US98/00863, which disclosure is incorporated by reference herein. Other forms of torque-override may also be used with the presently preferred closure. 
     As shown in FIG. 2, upper housing  18  includes a pair of helical cap mounting members  36  coupled to cylindrical body  26  and lower housing  18  includes a pair of position-locator lugs  50  coupled to cylindrical body  21 . As the handle  13  and upper housing  18  are rotated in a cap-installation direction  39 , mounting members  36  engage complementary formations  37  on filler neck  12  to pull closure  10  axially into filler neck  12 . Additional description of mounting members  36  and position-locator lugs  50  is disclosed in PCT Patent Application Serial No. PCT/US98/00863, which disclosure is incorporated by reference herein. 
     Upper housing  18  further includes a middle flange  38  coupled to cylindrical body  26 . Middle flange  38  engages an upper end  45  of filler neck  12  to provide a stop for the axially inward movement of upper housing  18  as the handle  13  is turned in a clockwise cap-installation direction  39 . According to an alternative embodiment, a C-shaped seal is coupled to an underside of the middle flange to engage and seal with the upper end of the filler neck. 
     As shown in FIG. 1, upper housing  18  also includes a lower flange  40  that extends radially inwardly. Lower flange  40  includes an inner edge  41  having an inside diameter that is less than the diameter of spring  24  so that spring  24  pushes against lower flange  40  when closure  10  is assembled. Inner edge  41  defines an aperture  43  in which spring mount  22  is positioned after assembly of closure  10 . Upper housing  18  also includes several axially downwardly extending cam followers  42  appended to an underside of lower flange  40  that engage cams  54  provided on lower housing  20  to provide the axial movement between upper and lower housings  18 ,  20 . In illustrated disclosure, the cams  54  are the “driven members ” and the cam followers  42  are the “drivers ” since rotation of the cam followers  42  about a central axis  11  of closure  10  (in response to rotation of handle  13  and upper housing  18  about central axis  11 ) causes cam follower  42  to ride on cams  54  and urge lower housing  20  downwardly along central axis  11  and in direction  21  (as shown in FIG. 3) to cause the seal  16  to seal against an inner wall of filler neck  12 . 
     Lower housing  20  includes a snap-receiving portion  46  that extends upwardly from upper surface  44  of lower housing  20 . Snap-receiving portion  46  includes a groove  47  formed at a lower end thereof for engaging spring mount  22 . Lower housing  20  includes a seal-receiving groove  48  sized to receive seal  16  as shown in FIG.  2 . As shown in FIG. 3, a pair of lugs  50  (one shown) are coupled to cylindrical body  21  of lower housing  20 . Lugs  50  engage a formation defining a notch  52  formed in filler neck  12  to prevent rotation of lower housing  20  during rotation of upper housing  18  by the handle  113 . Additional detail of the relationship between and configuration of lugs  50  and filler neck  12  is disclosed in PCT Patent Application Ser. No. PCT/US96/19589 to Robert S. Harris and Jeffery Griffin and titled Quick-On Fuel Cap which is expressly incorporated by reference herein. 
     As shown in FIG. 1, lower housing  20  includes several cams  54  (two shown) positioned on upper surface  44  to engage cam followers  42  of upper housing  18  to provide the axial movement between upper and lower housings  18 ,  20 . Additional detail of the relationship between and configuration of cam followers  42  and cams  54  is disclosed in PCT Patent Application Ser. No. PCT/US95/01561 to Robert S. Harris and Jeffery Griffin and titled Quick-On Cap with Removal Delay Mechanism which is expressly incorporated by reference herein. 
     In a preferred embodiment, the cam  54  is shown to extend upward toward an upper surface  44  of the lower body  20 , and configured to engage a cam follower  42  depending from a lower flange  40  of the upper body  18 . In another preferred embodiment, the cam  54  and cam follower  42  positions may be reversed; specifically, the cam  54  may depend downwardly from a lower flange  40  of the upper body  18  and the cam follower  42  may extend upwardly from an upper surface  44  of the lower body  20 . 
     A pressure/vacuum-relief valve may also be provided with closure  10 . For example, a pressure/vacuum-relief valve, a pressure-relief valve, or a vacuum-relief valve may be positioned within the body of the lower housing. A suitable pressure/vacuum-relief valve is described in PCT Patent Application Ser. No. PCT/US95/01561, which disclosure is incorporated by reference herein. Other configurations of pressure/vacuum-relief valves may also be used. 
     Spring mount  22  includes a cylindrical body  56  and a flange  58  coupled to an upper end of cylindrical body  56  as shown in FIG.  1 . Flange  58  has an outside diameter that is greater than the diameter of spring  24  so that ejector spring  24  pushes against flange  58  to bias spring mount  22  upwardly. 
     Spring mount  22  also includes a snap ridge  60  coupled to a lower end of cylindrical body  56  to rigidly couple spring mount  22  to lower housing  20 . During assembly of closure  10 , body  56  of spring mount  22  is positioned within spring  24 , as shown in FIG. 1, and inserted through aperture  43  of upper housing  18 . Snap ridge  60  is forced over snap-receiving portion  46  into groove  47  to couple spring mount  22  to lower housing  20 . 
     After assembly, ejector spring  24  is positioned between flange  58  of spring mount  22  and lower flange  40  of upper housing  18 . Spring  24  is slight compressed to provide an upward bias of spring mount  22  relative to upper housing  18 . Because of the coupling of spring mount  22  to lower housing  20 , lower housing  20  is also provided with an upward bias toward upper housing  18 . 
     During installation, lower housing  20  moves downwardly in direction  21  away from upper housing  18  as shown in FIG. 3 as upper housing  18  is rotated in clockwise direction  39  relative to filler neck  12  in response to clockwise rotation of the handle  39  that is coupled to upper housing  18 . Lower housing  20  and seal  16  do not rotate relative to filler neck  12  during rotation of the handle  13  and the upper housing  18  in the clockwise cap-installation direction  39 . Instead, lug  50  carried on lower housing  20  engages notch  52  on filler neck  12  to prevent any substantial rotation of lower housing  20  in clockwise direction  39  relative to filler neck  12  so that upper housing  18  is allowed to rotate relative to lower housing  20 . 
     During rotation of upper housing  18  in the tightening or cap-installation direction  39  with respect to lower housing  20 , cam followers  42  of upper housing  18  ride on cams  54  of lower housing  20  to drive lower housing  20  and seal  16  axially inward in direction  21  further into filler neck  12 . Cam followers  42  continue to ride on cams  54  until each cam follower  42  overrides a detent  62  provided on upper surface  44  adjacent the top of the cam slope defined by cams  54 , and is stopped by stop  64 . Detents  62  cooperate with cam followers  42  to provide latching engagement between upper and lower housings  18 ,  20  and cooperate with stops  64  to prevent accidental sliding of cam followers  42  back down cams  54  in the loosening direction  72 . 
     During rotation of the handle  13  in the clockwise tightening direction  39 , upper and lower housings  18 ,  20  are pulled into filler neck  12  by the rotational engagement of helical mounting members  36  of upper housing  18  and lower housing  20  is pushed further into filler neck  12  by the engagement of the “driving” cam followers  42  of upper housing  18  with “driven” cams  54  of lower housing  20 . As illustrated in FIG. 3, upper and lower housings  18 ,  20  move a first distance  66  into filler neck  12  during installation and upper housing  18  pushes lower housing  20  into filler neck  12  by an additional distance  68  so that lower housing  20  and seal  16  travel a total distance equal to the sum of distances  66 , 68  during rotation of the handle  13  in cap-installation direction  39 . During the axially inward movement, seal  16  engages filler neck  12  to form a substantial seal therewith to block the flow of fuel and fuel vapor from escaping from filler neck  12  between seal  16  and filler neck  12 . 
     During the movement of lower housing  20  away from upper housing  18 , ejector spring  24  is compressed by distance  68  to store energy. Because spring mount  22  is coupled to lower housing  20 , lower housing  20  also moves axially inward relative to upper housing  18  so that flange  58  of spring mount  22  and lower flange  40  of upper housing  18  compress ejector spring  24  there between. 
     The additional compression of ejector spring  24  creates additional upward biasing of lower housing  18  and seal  16  toward upper housing  18  and out of filler neck  12 . However, this additional force is not able to move lower housing  18  and seal  16  relative to upper housing  18  and filler neck  12  because of the latching engagement provided by detent  62  of lower housing  20  for each cam follower  42 , which latching engagement blocks counterclockwise rotation of upper housing  18  relative to filler neck  12  and thus movement of upper housing  18  out of the filler neck under the urging of the ejector spring  24 . 
     When the handle  13  is rotated in a counterclockwise cap-removal direction  72 , lower housing  20  is pulled upwardly to a position adjacent upper housing  18  so that seal  16  is pulled from engagement with filler neck  12 . Furthermore, engagement of helical mounting members  36  of upper housing  18  and complementary formations  37  of filler neck  12  pull upper and lower housings  18 ,  20  and seal  16  further out of filler neck  12  so that closure  10  can be removed from filler neck  12 . 
     As mentioned above, a detent  62  and stop  64  are positioned to lie adjacent to an end of each cam surface  54  in order to prevent accidental sliding of the cam followers  42  down the cam surfaces  54 . Of course, the cap may move in the loosening direction  72  if one applies sufficient torque to overcome the restraining force created by the cam followers  42  engaging the detents  62 . Once sufficient torque is applied to the handle  13  in the loosening direction  72 , the cam followers  42  will move past the detents  62  and will travel along the cam surfaces  54  toward the wall  63  (shown in FIG.  1 ). 
     Compressed ejector spring  24  aids in the removal of closure  10  by releasing the stored energy at the proper time during cap removal. During rotation of the handle  13  of closure  10 , cam followers  42  are forced over detents  62  and cam followers  42  continue to ride along cams  54  so that lower housing  20  moves upwardly to a position adjacent upper housing  18  as shown in FIG.  2 . This movement of lower housing  20  relative to upper housing  18  is assisted by the additional compression applied to ejector spring  24  during installation of the cap. Ejector spring  24  provides a force that pushes up on spring mount  22  to pull lower housing  20  toward upper housing  18  to assist in ejecting closure  10  from filler neck  12  during cap removal. 
     This force also aids in pulling seal  16  along filler neck  12  so that a user of closure  10  does not have to apply as much force during removal of closure  10  from filler neck  12 . During removal, the user must apply an amount of torque to closure  10  to turn upper housing  18  relative to filler neck  12 . A portion of this torque is used to pull seal  16  axially along filler neck  12 . As previously mentioned, when seal  16  is swollen, the amount of torque required to remove closure  10  increases due to the increased compressive force applied to seal  12 . The stored energy in ejector spring  24  reduces the amount of torque required to remove closure  10  by pulling lower housing  18  and seal out of filler neck  12 . Thus, by compressing ejector spring  24  to store energy during installation of closure  10 , this stored energy may be released to aid in removal of closure  10  during removal. 
     The ejector spring may also be positioned in other locations to aid in removal of the closure from the filler neck. For example, the ejector spring may be positioned between the lower housing member and the filler neck so that the spring is compressed between the filler neck and the lower housing member during installation. This compression will aid in removal of the closure by urging the lower housing member and the seal out of the filler neck. Furthermore, the ejector spring may be positioned between the filler neck and the upper housing or the handle so that the spring is compressed between the filler neck and the upper housing or the handle during installation. This compression will aid in removal of the closure by urging the upper housing, the lower housing, and the seal from the filler neck. 
     A fuel tank closure  110  in accordance with an alternative embodiment of the present disclosure is shown in FIG.  4 . Closure  110  is movable between a disengaged position (not shown) and an installed position as shown in FIG. 4 with closure  110  positioned in a fuel tank filler neck  112 . Closure  110  includes a housing assembly  114  and a seal  116  coupled to housing assembly  114 . While closure  110  is in the installed position, seal  116  engages filler neck  112  to substantially seal filler neck  112 . 
     While seal  116  is engaged with filler neck  112 , fuel (not shown) can cause seal  116  to swell. This swelling increases the compression force between seal  116  and filler neck  112 . This increased force creates more resistance to removal of seal  116  from filler neck  112  making closure  110  more difficult to remove from filler neck  112 . 
     To aid in removal of seal  116  from filler neck  12 , closure  110  and seal  116  are axially biased outwardly to provide a force that assists in pulling seal  116  from filler neck  112 . Filler neck  112  includes a compression spring  124  that provides this force. Spring  124  is compressed to store energy during installation of closure  110   112 . During removal of closure  110 , this stored energy is released to aid in pulling closure  110  and seal  116  from filler neck  112 . 
     Housing assembly  114  includes an upper housing  118  and a lower housing  120  that carries seal  116 . Lower housing  120  can move rotationally relative to upper housing  18 . Further details of the operation of upper and lower housing  118 ,  120  and the remainder of closure  110  is disclosed in PCT Patent Application Ser. No. PCT/US96/19589 which has been expressly incorporated herein. 
     As previously mentioned, spring  124  is compressed to urge upper housing  118  of closure  110  upwardly out of filler neck  112 . Upper housing  118  includes a cylindrical body  126  and an upper flange  128  coupled to cylindrical body  126 . A handle is coupled to upper flange  128  for a user to grip and turn upper housing  118  when installing closure  110  into filler neck  112 . As the handle of closure  110  is rotated, spring  124  is compressed to provide the biasing force between closure  110  and filler neck  112 . 
     Filler neck  112  includes a body portion  111  having a spring-receiving groove  122 . As shown in FIG. 4, spring  124  is positioned in groove  122  to support spring  124  during compression. Filler neck  112  further includes a spring guide  130  having a body portion  132  and a flange  134  coupled to body portion  132 . During rotation of the handle  13 , housing assembly  114  is pulled into filler neck  112 . Axially inward movement of housing assembly  114  into filler neck  112  causes seal  116  to engage filler neck  112  to form the seal blocking the flow of fuel and fuel vapor from escaping from filler neck  112  between seal  116  and filler neck  112 . 
     Upper flange  128  of upper housing  118  is pushed into engagement with support flange  134  of spring guide  130 . As spring guide  130  is pushed downwardly, spring  124  is compressed to store energy. The compression of spring  124  creates the upward bias against housing assembly  114  and seal  116 . As previously mentioned, the compression later aids in the removal of closure  110  by releasing the stored energy to provide the force that pushes up on upper flange  128  and the remainder of closure  110  to help push closure  110  from filler neck  112 . 
     This force also aids in pulling seal  116  along filler neck  112  so that a user of closure  110  does not have to apply as much force during removal of closure  110  from filler neck  112 . During removal, the user must apply an amount of torque to closure  110  to turn upper housing  118  relative to filler neck  112 . A portion of this torque is used to pull seal  116  axially along filler neck  112 . When seal  116  is swollen, the amount of torque required to remove closure  110  increases due to the increased compressive force applied to seal  116 . The stored energy in spring  124  reduces the amount of torque required to remove closure  110  by biasing housing assembly  114  and seal  116  out of filler neck  112 . Thus, by compressing spring  124  to store energy during installation of closure  110 , the stored energy may be used to aid in remove of closure  110 . 
     The spring may also be positioned in other locations to aid in removal of the closure from the filler neck. For example, the spring may be positioned between the lower housing member and the filler neck so that the spring is compressed between the filler neck and the lower housing member during installation. This compression will aid in removal of the closure by urging the lower housing member and the seal out of the filler neck. Furthermore, the spring may be directly coupled to the closure to move into engagement with the filler neck to provide the biasing force. 
     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.