Abstract:
A vent assembly for use on a tank containing liquid fluid requiring venting, the assembly comprising: a vent portion that includes a top surface, and at least one venting channel, each venting channel capable of providing fluid communication between a tank on which the vent portion is disposed and atmosphere external the tank, the channel having an exit to atmosphere that is disposed on the vent portion below the top surface of the vent portion.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to and the benefit of U.S. provisional patent application No. 60/741,132, filed Nov. 30, 2005, entitled CAP FOR FUEL TANKS, which is hereby incorporated by reference for all purposes as if included herein in its entirety. 
     
    
     BACKGROUND  
       [0002]     The inventive subject matter relates to a vented cap and other vent assemblies primarily for tanks containing liquids that require venting. The inventive subject matter is particularly directed to venting fuel tanks used with motor vehicles. The fuel tank may be for holding gasoline, diesel, alcohol, and other liquid fuels for an internal combustion engine. In certain respects, the inventive subject matter relates to a vented fuel cap having a rollover valve, or check valve for use with fuel tanks on motor vehicles.  
         [0003]     Fuel tanks for many motor vehicles include direct venting so a vacuum doe not form in the tank as fuel is withdrawn by an associated motor or engine. A problem with such fuel tanks is that if tank is tipped or turned over, the fuel in the fuel tank can leak out of the vent holes in the fuel cap potentially causing disastrous results. This is particularly problematic for off-road vehicles, such as motorcycles and all terrain vehicles, which are especially at risk of tipping or turn over.  
         [0004]     Vented fuel caps are known that include an angle-dependent valve, such as a rollover or check valve device that operates to prevent fuel from leaking from the vents holes of the fuel cap when a fuel tank is tipped or turned over. For example, one known fuel cap includes a hose that extends outwardly from the center of the fuel cap that includes a rollover, or check, valve device at the end of the hose distal from the fuel cap. While a vented fuel cap of this type generally operates as designed, problems may still occur. For example, if the hose breaks, the check valve functionality may be lost. Also, for example, the hose and rollover-valve device can inflict a puncture-wound to a rider sitting in proximity to the tank.  
         [0005]     Another known vented fuel cap includes a rollover-valve device located under the cap portion of the fuel cap and has a venting hole that emerges through the top side of the cap portion. There are problems with this arrangement too. For instance, the venting-hole arrangement can become clogged with dirt or other debris, eliminating the benefits of the venting hole.  
         [0006]     In view of the foregoing and other problems, there is a need for improved caps for fuel tanks that have an angle-dependent valve, such as a rollover or check valve device that is not easily blocked or broken, and do not present a potential source of a puncture-wound injury.  
       SUMMARY  
       [0007]     A vent assembly for use on a tank containing liquid fluid requiring venting, the assembly comprising: a vent portion that includes a top surface, and at least one venting channel, each venting channel capable of providing fluid communication between a tank on which the vent portion is disposed and atmosphere external the tank, the channel having an exit to atmosphere that is disposed on the vent portion below the top surface of the vent portion.  
         [0008]     These and other embodiments are described in more detail in the following detailed descriptions and the figures.  
         [0009]     The foregoing is not intended to be an exhaustive list of embodiments and features of the present inventive concept. Persons skilled in the art are capable of appreciating other embodiments and features from the following detailed description in conjunction with the drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The inventive subject matter is illustrated by way of example and not by limitation in the accompanying figures in which like reference numerals indicate similar elements and in which:  
         [0011]      FIG. 1  depicts a side cross-sectional view of an assembled fuel cap according to the inventive subject matter;  
         [0012]      FIG. 2  depicts an side cross-sectional exploded view of a fuel cap according to the inventive subject matter; and  
         [0013]      FIG. 3  depicts a top view of a slotted disc according to the inventive subject matter. 
     
    
     DETAILED DESCRIPTION  
       [0014]      FIGS. 1 and 2  depict a vented fuel cap  100 , according to one possible embodiment of the inventive subject matter. The cap has an angle-dependent valve, which as used herein means a valve or other flow restrictor that is provided in the cap to block fluid from flowing from a tank and out of a channel used for venting the tank, the flow being blocked upon a predetermined tilting of the cap from an initial position, which typically is an upright position on top of a fuel tank (as represented by the orientation of cap  100  in  FIG. 1 ). A typical angle-dependent valve is a rollover valve or check valve, and the following discussion will be in terms of such a construction.  
         [0015]     Fuel cap  100  includes a cap portion  101 , a slotted disc  102 , a valve assembly  103 , a splash cover  104 , and a gasket  125 . Valve assembly  103  operates to prevent fuel from leaking through venting channels  107  in the fuel cap when a fuel tank on which the fuel cap is installed is tipped sufficiently or turned over. Motor vehicles that are particularly prone to tipping or turn over include motorcycles, ATVs, personal watercraft, and other recreational, transport or work vehicles that are prone to tipping or turnover, particularly those where the rider and/or fuel tank is unenclosed.  
         [0016]     Cap portion  101  includes a top surface  101   a , a bottom surface  101   b , an inner surface  105 , a vent chamber  106 , vent channels  107  with exit openings, communicating with the atmosphere external to the tank  200 , threads  108  and threaded blind holes  109 . Inner surface  105  receives slotted disc  102  when fuel cap  100  is assembled. Vent channels  107  are in venting communication with a fuel tank via vent chamber  106  and extend away from top surface  101   a  and emerge from bottom surface  101   b . While two vent channels are depicted, it should be understood that any number of vent channels  107  can be used. Additionally, while channels  107  are depicted as emerging from bottom surface  101   b , it should be understood that channels  107  can emerge from a surface that is below top surface  101   a . Threads  108  engage with corresponding threads of a fuel tank filler neck  200 . Cap portion  101  is typically formed from any suitable material, such as aluminum, that is sufficiently strong and durable to function as a cap for a fuel cap assembly.  
         [0017]     As shown in  FIG. 3 , slotted disc  102  includes a vent passage  110 , venting aperture  111 , and screw apertures  112 . When slotted disc is received by inner surface  105  of cap portion  101 , vent aperture  111  is in venting communication with vent chamber  106  through vent passage  110 . While vent passage  110  is depicted as generally transversing slotted disc  102  in a bisecting configuration, it should be understood that vent passage  110  could have any of a number of configurations, such as at least one or more radially configured vent passages. Additionally, slotted disc  102  can be formed from any suitable material, such as aluminum, that has sufficient strength and durability to be held against cap portion  101 .  
         [0018]     Valve assembly  103  is a gravity-sensitive valve arrangement that blocks a passage based on a predetermined amount of tilting. In one possible example, a suitable valve arrangement is a check valve that includes a valve mount  113 , a ball valve seat  114 , a ball  115  and a return-air valve  116 . Valve mount  113  is held against surface  117  of slotted disc  102  by screws  118  passing through apertures  119  in valve mount  113  and apertures  112  of slotted disc. Screws  118  are received in threaded blind holes  109  in cap portion  101 . Ball valve seat  114  is received in cavity  120  of valve mount  113 . Cavity  120  is then in venting communication with vent aperture  111  of slotted disc  102 . Ball  115  is received in vent cavity  121  of ball valve seat  114 . Vent cavity  121  is in venting communication with cavity  120 . Ball  115  can be made from any suitable material that is denser and therefore heavier than the fuel that will be contained in the fuel tank on which fuel cap  100  will be used. Return-air valve  116  is also received in vent cavity  121  of ball valve seat  114 , thereby retaining ball  115  within vent cavity  121 . The components of valve assembly  103  can be formed from any suitable material, such as aluminum, that provides sufficient strength and durability to operate as a rollover (check) valve assembly.  
         [0019]     Splash cover  104  includes a barb engagement slot  122  and vent channels  123 . Barb engagement slot  122  engages barb  124  on valve mount  113 , thereby fixedly holding splash cover  104  about valve assembly  103 . Splash cover  104  can be formed from any suitable material, such as plastic, that provides sufficient strength and durability to be used as a splash cover for a vented fuel cap.  
         [0020]     Gasket  125  fits into cap portion  101  and forms a seal with the filler neck of the fuel tank. Gasket  125  can be formed from any suitable gasket-type material, such as rubber.  
         [0021]     In a typical operation, fuel cap  100  is installed in the filler neck of a fuel tank of a vehicle in a well-known manner so that fuel cap seals the fuel tank.  
         [0022]     When the fuel tank and fuel cap  100  are in a normal, upright position, there is a vent passage through vent channels  123 , return-air valve  116 , vent cavity  121 , cavity  120 , vent aperture  111 , vent passage  110 , vent chamber  106  and channels  107 . In the normal, upright position, ball  115  sits on return-air valve  116 , thereby allowing normal venting to occur.  
         [0023]     When the fuel tank and fuel cap  100  are in a sufficiently tilted or an inverted position, ball  115  closes vent cavity  121 , thereby preventing fuel from spilling from fuel cap  100  through vent channels  123 , return-air valve  116 , vent cavity  121 , cavity  120 , vent aperture  111 , vent passage  110 , vent chamber  106  and channels  107 .  
         [0024]     While the inventive subject matter has been discussed in terms of a removable cap, a tank might be constructed with a fixed section incorporating an angle-dependent valve as contemplated herein. The tank could, for example, include a separate openable cap or other mechanism for adding or draining fluid from the tank, in addition to the fixed valve assembly. Accordingly, instead the inventive venting features of the cap may be instead implemented as a fixed “venting portion” on a tank.  
         [0025]     Persons skilled in the art will recognize that many modifications and variations are possible in the details, materials, and arrangements of the parts and actions which have been described and illustrated in order to explain the nature of this inventive concept and that such modifications and variations do not depart from the spirit and scope of the teachings and claims contained therein.