Abstract:
A vehicle fuel or gas tank is subjected to either a build up of pressure or a negative pressure, and in view of this inlet and outlet vents are provided in the fuel cap to balance the pressure with the atmosphere, and this balance of fuel tank pressure is attained by covers of vents in the fuel cap and the covers having an umbrella or parabolic shape or the vents may be covered by reed valves. The disclosure of covers of vents as described in this invention then obviates the use of coiled metal springs to control vents in vehicle fuel caps.

Description:
BACKGROUND OF INVENTION 
     Proper venting of gasoline fuel tanks in cars or vehicles is important to reduce emissions of hydrocarbon fuels into the atmosphere and thus to reduce pollution of the atmosphere. Disclosure is made of a fuel tank cap, with controlled venting both into and out of the fuel tank, and a gasket sealing the cap to the fill pipe of the fuel tank, and the vents maintain minimum ventage of the hydrocarbon fuel vapors. 
     SUMMARY OF THE INVENTION 
     Disclosure is made of a car or vehicle fuel cap having an inlet vent valve and an outlet vent valve and each vent valve held in closed position until activated to open position by a pressure differential of pressure build up in the fuel tank for the outlet vent valve to open or the inlet vent valve actuated by negative pressure in the fuel tank, and the vent valves can be described as umbrella shape check valves, or reed valves as alternates to the umbrella valves. This invention then obviates the use of coil compression springs as now used in fuel caps for vent controls. 
     OBJECTS OF THIS INVENTION 
     An object of this invention is to disclose and claim a vehicle fuel cap having an inlet vent and an outlet vent and the outlet vent extending upwards, held in closed position by an umbrella shaped cover extending over the vent aperture, and the edges of the umbrella shaped cover riding on the periphery around the outlet vent aperture and the umbrella shaped cover held in position over the outlet vent by fastening of the umbrella shaped cover onto a pillar extending from the vent aperture surface to the center of the concave surface of the umbrella shaped cap, and an inlet aperture extending downward in the fuel cap, and a pillar extending downward next to the inlet aperture and an inverted umbrella shaped cover extending over the inlet aperture, and the inverted umbrella shape cover attached to the pillar and the edge of the concave shape of the inverted umbrella shape extending over the inlet vent aperture. 
     Another object is to disclose and claim, as an alternate to umbrella shaped valves, reed valves in a fuel cap, and one reed valve in an outlet vent aperture and one reed valve in the inlet aperture, and the reed valves actuated by differential pressure inside and outside of the fuel tank. 
     PRIOR ART 
     U.S.Patents:
         U.S. Pat. No. 4,337,873 for FUEL CAP WITH POPPET VALVES. Spring loaded valves are disclosed.   U.S. Pat. No. 4,436,219 for SEALING CAP FOR GAS TANK. Pressure and vaccum relief valves are shown   U.S. Pat. No. 4,765,505 for DELAYED ACTUATION FUEL CAP. The lost motion of the hub to break the seal on the fill pipe.   U.S. Pat. No. 5,108,001 for PRESSURE RELEASE VENT CAP. Spring loaded vents are disclosed.   U.S. Pat. No. #5,996,829 for FUEL TANK CAP. Disclosure is made of a fuel tank cap to control the pressure in a fuel tank by opening and closing a rubber valve.   U.S. Pat. No. #6,003,709 for FUEL CAP. Electrically conductive fuel cap.       

     None of the above cited patents anticipate or make obvious the disclosure and claims of this present invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       ! 
       DRAWING LEGENDS 
       ! 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     This invention is to disclose and claim vehicle fuel cap venting apparatus for controlling positive or negative pressure in a vehicle fuel tank and is described as follows. 
     FIG. 1 is a cross section elevational view of complete assembly of fuel cap of this invention, and FIG. 9 is an elevational view of the complete assembly of the of vehicle fuel cap venting apparatus of this invention. 
     The vehicle fuel cap apparatus of this invention includes a vehicle fuel cap apparatus (see FIG. 1) showing the top of fuel cap  1 , and ridge  2  on top of the fuel cap and components of which are shown in FIGS. 3,4,5,6,7, and 8 and an inlet vent aperture  25 , FIGS. 19, 21 and an outlet vent aperture  20 , and the outlet vent  20  extending through the flat top panel  27  of the fuel cap body  5 , and the vent  20  held in “closed” position (see FIGS. 5, 6,15,19) by an by an umbrella or parabola shaped cover  4  (see FIGS. 13, 14, 15, 19) extending over the vent aperture  20 , and the edge  28  of the umbrella parabolic shaped cover  4  resting on the periphery  27  around the outlet vent aperture  20  and the umbrella parabola shaped cover  4  held in position (see FIGS. 5,15,19) over the outlet vent aperture  20  by fastening of the umbrella parabola shaped cover  4  onto a pillar post  19  extending from flat top  27  of the fuel cap body  5  through a center mounting aperture  11  of the concave side  23  of the outlet vent umbrella parabola shaped cover  4 , and the umbrella cover edge  28  (FIGS. 14,19) extending over the outlet vent aperture  20 , and to insure balance of the pressure in the fuel tank there is an inlet vent aperture  25  through the top  27  of the fuel cap body  5 , and a pillar post  18  for inlet vent inverted umbrella parabola shaped cover  6  (FIG. 7) extending downward on the vehicle side of the flat top  27  of the fuel cap  5  and covering the inlet vent aperture  25  and the inverted umbrella parabola shape cover  6  attached to the pillar post  18  (FIG. 19) extending through mounting hole  12  in umbrella cover  6 , and the edge  29  (FIGS. 17,22)  24  ( FIG.  22) of the concave side of the inverted umbrella parabola shape cover  6  extending over the inlet vent aperture  25 . 
     Referring now to FIGS. 1,8, and 9, sealing gasket  7  is shown, which seals the cap in the filler pipe of the vehicle fuel tank. FIG. 18 is a plan view of the gasket  7 . 
     As an alternate apparatus to control the pressure in a vehicle fuel tank cap, reed valves are shown in FIGS. 20,21 in a fuel cap body  5 . Outlet reed valve  13  is mounted on the top surface of top section  27  of the fuel cap body  5 , and one reed valve  13  mounted on the bottom surface of top  27 , of fuel cap body  5  on inlet vent aperture  15  and each reed valve  13 , 13 ′ is attached on one end to the top surface  27  of the fuel cap body. The reed valves can be identified as the name implies, a reed  13  or  13 ′ one end of which is attached at  16 ,  16 ′ to the fuel cap body FIG. 21 as stated above and the ends  26 , 26 ′ of the reeds opposite the attached ends shut-off of valve faces  17 , 17 ′ fitting over the inlet and outlet apertures  14  and  15  respectively, with reed  13  mounted on the top surface of top  27  of fuel cap body  5 . 
     The reeds  13   13 ′ being flexible are actuated by inlet or outlet pressure on the shut-off valve face contacts  17 ,  17 ′ to release either excess pressure in the fuel tank, or low pressure or partial vacuum in the fuel tank. 
     Referring now to FIG. 10, there is shown elevation view of top component  1 , of assembly of FIG. 3, rotated 90° of fuel cap  1 , showing ridge  2 , on top of fuel cap  1 . FIG. 11 is plan view of bottom, of top of fuel tank cap  1 , showing cogs  9  on inner wall of fuel cap  1 . FIG. 12 is plan view of torque plate  3 , showing mount aperture  14  to fit over pins  30 , on top of fuel cap body  5  and pivot arms  8 , on torque plate  3 , and the pivot arms  8  flexibly mounted on pin mounts  10 , to positively hit cams  9  on counter clock-wise rotation to remove the fuel cap assembly from the fill pipe, and pivot arms  8  riding over the cogs  9  on clock-wise rotation of the fuel cap assembly of FIG. 9. 
     FIG. 16 is the top plan view of inlet vent aperture umbrella cover  6 . FIG. 20 is plan view of reed valves  13 ,  13 ′ mounted on top surface of fuel cap body  5 , and outlet vent  20  and inlet valve  25  shown covered by shut off valve faces  17 , 17 ′. 
     FIG. 23 is a cross section view of outlet vent umbrella cover  4  and FIG. 24 is a plan view of top of fuel cap body showing the mounting locations of outlet and inlet vents and umbrella vent covers in approximate relationship each to the other. 
     The periphery  22  of the vent apertures are shown as legend  27   
     The rim edge  24  (FIG. 22) of inlet inverted umbrella cover  6 , is in contact with surface of top of fuel cap  5 , and the edge  28  of umbrella cover  4  is in contact with the surface  27  of fuel cap  5 . 
     The umbrella parabola shaped covers  4  and  6  when mounted over the apertures as disclosed above, serve as vent control by the edges  24  or  28  being flexed and raised off of contact with the surface around the apertures, to allow for pressure or vacuum relief through its respective vent  20  or  25 . 
     It is to be pointed out that the apertures  20  and  25  are each adjacent to its respective pillar post  19  and  18  under umbrella parabola shape cover  4  and  6  respectively. 
     The preferred material for the inlet and outlet vent umbrella covers  4  and  6  is fluorocarbon (fluoroplastic) moldings, having a Shore A, 55 to 65 hardness. 
     The other components may be molded by plastic material such as nylon or similar materials. 
     The threads  30 , of the fuel cap body  5  are shown as coarse threads, but these threads may be replaced by quarter run threads or other means for attaching the fuel cap to the fill pipe. 
     The reed valve arms are made of stainless steel or similar inert metal, and the shut-off valve face  17 ,  17 ′ contacts on the arms are preferably of plastic material such as nylon, or fluoropolymer or the metal of the arms would be sufficient to hold the vent closed against a pressure of 1—3 pounds per square inch. 
     Further description includes an outlet aperture  20  adjacent to a pillar  19 , in the fuel cap  5 , and an aperture cover  4 , having an umbrella or parabola shape mounted on the pillar  19 , and the aperture cover concave side  23  edge landed on the surface  27  around the pillar  19  and the outlet aperture  20  and the inlet aperture  25  adjacent to a second pillar  18  in the fuel cap body  5 , and a second aperture cover  6  having an umbrella or parabola shape FIGS. 22 and 23, mounted on the second pillar  18  and the concave side  24 , of the aperture cover landed on surface around the second pillar  18  and the inlet aperture  25 , on the underside flat top  27  of fuel cap body  5 . 
     The fluoropolymer thermoplastic material moldings of aperture covers should have a preferred Shore A hardness of 45 to 65, with a preferred range of 50 to 60 hardness. 
     The word “landed” means the edges  24  and  28  of the out-let and inlet aperture covers  4  and  6  are in contact with the respective surface around the pillars  18 , 19  and the apertures  20  and  25 , and the attachment of the outlet/inlet umbrella covers  4  and  6  to the pillars  19  and  18  is tight to prevent any vent leakage between the pillars and the umbrella covers. 
     As an alternative, to obviate springs in a vehicle fuel cap outlet and inlet vent apparatus a first outlet aperture  20  vent in a fuel cap body  5  and a metal reed  13  attached on one end  6  and adjacent to outlet aperture  20  vent the end  26  of the reed  13  opposite to attached end  16  extending over aperture  20  to close the outlet aperture  20 , end of the metal reed  13  opposite to the attached end in shut off contact with the outlet aperture vent  20 , and, an inlet aperture  25  in the fuel cap body  5 , a second metal reed  13 ′ attached to one end  16 ′ and adjacent to aperture  25  for inlet vent, the end  26 ′ of the second metal reed  13 ′ opposite to attached end  16 ′, extending to cover inlet aperture vent  25 , and end  26 ′ of the second metal reed opposite to the attached end  16  in shut off contact with the aperture  25 . 
     In all of the above discussion and disclosure, the umbrella parabola covers  4  and  6 , and reed valves  13  and  13 ′ are actuated to vent either in or out by a pressure difference between the fuel tank and the atmosphere pressure.