Abstract:
A roll-over valve attaches over an existing carburetor float bowl vent tube and closes when a car is involved in a crash to prevent or reduce fuel from escaping from a tilted or inverted carburetor and starting a fire. Carburetors are used in many special interest cars and race cars. The carburetors include float bowls containing fuel and the float bowls are vented to outside air by the carburetor vent tubes. The carburetor vent tubes are generally vertical tubes reaching upward from the carburetor into an air cleaner or the volume above the carburetor. The roll-over valve includes a compression fitting or other connector and is easily fitted to the carburetor.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to preventing or reducing fuel leaks during accidents and in particular to a roll-over valve to prevent or reduce fuel leaks from a carburetor when a race car rolls in an accident. 
         [0002]    While fuel injection is commonly used in production automobiles, both enthusiasts and many classes in automobile racing use carburetors. In the past, fires resulting from accidents were both common and often life threatening. Many improvements have been made in the areas of fuel cells and fuel tank roll-over valves, reducing the occurrence of fires. Unfortunately, fires still result from fuel escaping from carburetors when cars roll over. 
       BRIEF SUMMARY OF THE INVENTION 
       [0003]    The present invention addresses the above and other needs by providing a roll-over valve which attaches over an existing carburetor float bowl vent tube and closes when a car rolls in a crash to prevent or reduce fuel from escaping and starting a fire. Carburetors are used in many special interest cars and race cars. The carburetors include float bowls containing fuel and the float bowls are vented to outside air. The vents are generally vertical tubes reaching upward from the carburetor into an air cleaner or into a volume above the carburetor. The roll-over valve includes a compression fitting and is easily fitted to the carburetor. 
         [0004]    In accordance with one aspect of the invention, there is provided a carburetor float bowl roll-over valve. The carburetor has at least one float bowl containing fuel and a cylindrical vertical float bowl vent tube extending upward from the carburetor and in fluid communication with the float bowl. The roll-over valve is fixed to the vent tube and includes a compression fitting nut and wedge, a body portion, a vertically sliding obstruction, and a top cap. The body portion includes a lower male threaded portion, a center portion, and an upper male threaded portion. The lower male threaded portion threadedly cooperates with the compression fitting nut to squeeze the compression fitting wedge radially to fix the roll-over valve on the vent tube. The center portion has an outside surface for cooperating with a tool. A vertical centered passage passes though the body portion and includes an inside shoulder forming a narrowing of the vertical centered passage. The vertically sliding obstruction resides inside the vertical centered passage above the inside shoulder, and bypass cuts in the vertical centered passage allow air to flow past the vertically sliding obstruction into and out of the float bowl to equalize pressure in the float bowl with ambient air pressure when the carburetor is upright. The top cap includes a cap lower portion having female threads for threadedly cooperating with the upper male threaded portion of the body portion, a port above the vertical centered passage in communication with ambient air, and a narrowing between the cap lower portion and the port to block passage of the vertically sliding obstruction into the port and to restrict an escape of fuel from the float bowl when the carburetor is sufficiently tilted or inverted. 
         [0005]    In accordance with another aspect of the invention, there is provided a carburetor and roll-over valve. The roll-over valve is connected serially with a float bowl vent tube wherein all of a flow through the vent tube is restricted to also pass through the roll-over valve. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0006]    The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
           [0007]      FIG. 1A  is a side view of a carburetor. 
           [0008]      FIG. 1B  is a top view of the carburetor. 
           [0009]      FIG. 2A  is a cross-sectional view of the carburetor taken along line  2 - 2  of  FIG. 1B . 
           [0010]      FIG. 2B  is a cross-sectional view of the carburetor taken along line  2 - 2  of  FIG. 1B  with the carburetor inverted and fuel escaping from vent tubes of the carburetor. 
           [0011]      FIG. 3  is a side view of the carburetor with roll-over valves according to the present invention fitted to the vent tubes to prevent or reduce the escape of fuel if the carburetor is inverted. 
           [0012]      FIG. 4  is a front view of the roll-over valve according to the present invention. 
           [0013]      FIG. 5  is a cross-sectional view of the roll-over valve according to the present invention taken along line  5 - 5  of  FIG. 4 . 
           [0014]      FIG. 6A  is a side view of a compression fitting nut element of the roll-over valve according to the present invention. 
           [0015]      FIG. 6B  is a top view of the compression fitting nut element of the roll-over valve according to the present invention. 
           [0016]      FIG. 6C  is a bottom view of the compression fitting nut element of the roll-over valve according to the present invention. 
           [0017]      FIG. 7A  is a side view of a compression fitting wedge element of the roll-over valve according to the present invention. 
           [0018]      FIG. 7B  is a top view of the compression fitting wedge element of the roll-over valve according to the present invention. 
           [0019]      FIG. 8A  is a side view of a body element of the roll-over valve according to the present invention. 
           [0020]      FIG. 8B  is a top view of the body element of the roll-over valve according to the present invention. 
           [0021]      FIG. 8C  is a bottom view of the body element of the roll-over valve according to the present invention. 
           [0022]      FIG. 9  is a cross-sectional view of the body element of the roll-over valve according to the present invention taken along line  9 - 9  of  FIG. 8A . 
           [0023]      FIG. 9A  is a cross-sectional view of the body element of the roll-over valve according to the present invention taken along line  9 - 9  of  FIG. 8A  with a ball element of the roll-over valve according to the present invention residing inside the body element. 
           [0024]      FIG. 10A  is a front view of a first cap element of the roll-over valve according to the present invention. 
           [0025]      FIG. 10B  is a side view of the first cap element of the roll-over valve according to the present invention. 
           [0026]      FIG. 10C  is a top view of the first cap element of the roll-over valve according to the present invention. 
           [0027]      FIG. 10D  is a bottom view of the first cap element of the roll-over valve according to the present invention. 
           [0028]      FIG. 11  is a detailed cross-sectional view of the body element of the roll-over valve according to the present invention taken along line  9 - 9  of  FIG. 8A . 
           [0029]      FIG. 12  is a detailed cross-sectional view of the first cap element of the roll-over valve according to the present invention taken along line  11 - 11  of  FIG. 10A . 
           [0030]      FIG. 13A  is a front view of a second cap element of the roll-over valve according to the present invention. 
           [0031]      FIG. 13B  is a top view of the second cap element of the roll-over valve according to the present invention. 
           [0032]      FIG. 14  is a cross-sectional view of the second cap element of the roll-over valve according to the present invention taken along line  14 - 14  of  FIG. 13A . 
           [0033]      FIG. 15A  is a front view of a third cap element of the roll-over valve according to the present invention. 
           [0034]      FIG. 15B  is a top view of the third cap element of the roll-over valve according to the present invention. 
           [0035]      FIG. 16  is a cross-sectional view of the third cap element of the roll-over valve according to the present invention taken along line  16 - 16  of  FIG. 15A . 
           [0036]      FIG. 17A  is a front view of a fourth cap element of the roll-over valve according to the present invention. 
           [0037]      FIG. 17B  is a top view of the fourth cap element of the roll-over valve according to the present invention. 
           [0038]      FIG. 18  is a cross-sectional view of the fourth cap element of the roll-over valve according to the present invention taken along line  18 - 18  of  FIG. 17A . 
           [0039]      FIG. 19  shows a carburetor having a housing above the primary side of the carburetor with a roll-over valve according to the present invention. 
       
    
    
       [0040]    Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0041]    The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
         [0042]    A side view of a carburetor  10  is shown in  FIG. 1A  and a top view of the carburetor  10  is shown in  FIG. 1B . The carburetor  10  is typical of four barrel carburetors used in many racing events and includes: float bowls  16 , metering blocks  22 , an air cleaner flange  14 , and float bowl vent tubes  12 . Other varieties of carburetors include one barrel carburetors, two barrel carburetors, and three barrel carburetors which may have one or two float bowls, but in general, nearly all carburetors include at least one float bowl and the float bowl has at least one float bowl vent. Engines commonly include one, two, three, four, or six carburetors. 
         [0043]    A cross-sectional view of the carburetor  10  taken along line  2 - 2  of  FIG. 1B  is shown in  FIG. 2A . The carburetor  10  further includes a float  18  in the float bowl  16 , and fuel  20  inside the float bowl  16 . The float controls a valve assembly to regulate the amount of fuel  20  inside the float bowl. The float bowl vent  12  vents the interior of the float bowl  16  to ambient air to provide neutral air pressure inside the float bowl. The float bowl vent is generally needed because pressure changes inside the float bowl will impact the fuel delivery to the engine. 
         [0044]    A cross-sectional view of the carburetor  10  taken along line  2 - 2  of  FIG. 1B  with the carburetor  10  inverted and fuel  20  escaping through the vent tubes  16  is shown in  FIG. 2B . In an accident, the unchecked flow of fuel  20  from the carburetor  10  of a hot engine is often the cause of fires. Such fires are extremely dangerous when combined with a crash on a race track because a driver may be injured or the driver&#39;s escape from the vehicle may be hampered by damage to the vehicle. Fuel may also escape from the float bowl  16  when the carburetor  10  is sufficiently tilted without being completely inverted. 
         [0045]    A side view of the carburetor  10  with roll-over valves  30  according to the present invention fitted to the vent tubes  16  to prevent or reduce the escape of fuel  20  if the carburetor  10  is inverted as shown in  FIG. 3 . The roll-over valves  30  side over the existing vent tubes  12 , and are fixed to the vent tubes  16  using compression fittings integral to the roll-over valves  30 . The roll-over valves  30  further include a simple ball valve which cooperates with a body portion of the roll-over valves  30  to allow a two way flow of air to maintain ambient air pressure in the float bowls  16  and close the roll-over valves  30  when the carburetor  10  is inverted to prevent or reduce the escape of fuel  20  and thereby prevent or reduce fires. The roll-over valves  30  generally reside inside an air cleaner  11  which filters air entering the engine, but may simply reside above the carburetor  10  on engines without air cleaners. 
         [0046]    A front view of the roll-over valve  30  according to the present invention is shown in  FIG. 4  and a cross-sectional view of the roll-over valve  30  taken along line  5 - 5  of  FIG. 4  is shown in  FIG. 5 . The roll-over valves  30  includes a compression fitting nut  32 , a compression fitting wedge element  34 , a body portion  38 , a ball  40 , and a first cap element  42 . The roll-over valves  30  slide over the float bowl vent  12  and the compression fitting nut  32  is tightened to the body portion  38  to hold the roll-over valves  30  in place. Such extremely simple installation, generally performed without removing the carburetor  10  from the engine, provides a simple and inexpensive safety device which in some cases, may save a driver&#39;s life. 
         [0047]    The roll-over valves  30  with the first cap element  42  is a preferred design for marine use. Boats are often required to attach an inverted “J” tube to the vent tube  12  to direct any escaping fuel into the carburetor bores to prevent or reduce the chance of a fire. Unfortunately, the additional fuel often causes the engine to stall. The roll-over valves  30  are positionable to direct any escaping fuel into the carburetor bores to meet requirements while also preventing or reducing the escape of fuel to prevent or reduce engine stalling. 
         [0048]    A side view of a compression fitting nut element  32  of the roll-over valve roll-over valves  30  is shown in  FIG. 6A , a top view of the compression fitting nut element  32  is shown in  FIG. 6B , and a bottom view of the compression fitting nut element  32  is shown in  FIG. 6C . A side view of a compression fitting wedge element  34  of the roll-over valve  30  is shown in  FIG. 7A  and a top view of the compression fitting wedge element  34  is shown in  FIG. 7B . The compression fitting nut element  32  and the compression fitting wedge element  34  of the roll-over valves  30  are common elements of known compression fittings and any similar elements sized for the float bowl vent  12 , for example, for a 5/16 inch tube, are suitable for use with the present invention. 
         [0049]    A side view of the body element  38  of the roll-over valve  30  is shown in  FIG. 8A , a top view of the body element  38  is shown in  FIG. 8B , a bottom view of the body element  38  is shown in  FIG. 8C , a cross-sectional view of the body element  38  taken along line  9 - 9  of  FIG. 8A  is shown in  FIG. 9 , a second cross-sectional view of the body element  38  taken along line  9 - 9  of  FIG. 8A  with the ball element  40  of the roll-over valve according to the present invention residing inside the body element is shown in  FIG. 9A , and a detailed cross-sectional view of the body element  38  taken along line  9 - 9  of  FIG. 8A  is shown in  FIG. 11 . The body element  38  includes an upper male threaded end  38   a  and an opposite lower male threaded end  38   c  separated by a center portion  38   b . The female threaded ends  38   a  and  38   c  preferably have a one half by 24 female thread. The center portion  38   b  includes opposing lands  48  allowing a tool to hold or turn the body element  38  for assembly and installation. 
         [0050]    The lower female threaded end  38   c  has a length L 3  of preferably approximately 0.3 inches and is configured to cooperate with the compression fitting nut element  32  and compression fitting wedge element  34  to form a common compression fitting allowing the roll-over valves  30  to slide over the vent tube  12  and tighten. 
         [0051]    The upper female threaded end  38   a  has a length L 1  of preferably approximately 0.3 inches and includes an interior with fingers  44  separated by gaps  46 . The fingers  44  support the ball  40  and the gaps  46  allow air to flow into or out of the float bowls  16  to maintain ambient air pressure inside the float bowls  16  while the engine is running. The fingers  44  and gaps  46  are preferably formed by first boring a centered passage  39  having a diameter D 3  and then milling three off center cuts into the centered passage and slightly deeper than the centered passage. The cuts  46  preferably provide an approximately 0.078 inch wide gap  46  outside the center passage  39 . 
         [0052]    In some applications, for example, with high horsepower and an air scoop forcing air into bowl vents, insufficient venting of the float bowls might result in the carburetor fuel curve becoming rich from an airflow restriction through the roll-over valve. In such instances, the cuts may be made deeper to provide more than 0.078 inch wide gaps  46 . 
         [0053]    The center portion  38   b  may be mostly cylindrical with two opposing lands  48 , hexagonal, square, or any shape allowing cooperation with a tool to hold or turn the center portion  38   b . The center portion  38   b  has a length L 2  which is preferably approximately 0.3 inches. 
         [0054]    The ball  40  preferably has a diameter of approximately 0.3125 inches. The diameter of the ball  40  is slightly smaller than the inside diameter D 3  of the centered passage  39  of the upper female threaded end  38   a  to allow the ball  40  to move easily within the centered passage  39 , and the ball  40  preferably has a diameter approximately 0.001 less than the centered passage  39 . 
         [0055]    The ball  40  is preferably made of plastic, steel, brass, or ceramic. A plastic or light weight ball is preferred for use in off-road and water vehicles because fuel may escape from the float bowl due to vertical accelerations of the vehicle going over a jump or waves, and a light weight ball is most likely to be lifted by the flow of escaping fuel to seal the valve  30  when the vehicle does not roll over. A ceramic ball is preferred where there is a greater risk of fire. A steel ball is suitable for most racing applications. 
         [0056]    A front view of the first cap element  42  of the roll-over valve  30  according to the present invention is shown in  FIG. 10A , a side view of the first cap element  42  is shown in  FIG. 10B , a top view of the first cap element  42  is shown in  FIG. 10C , a bottom view of the first cap element  42  is shown in  FIG. 10B  and a detailed cross-sectional view of the first cap element  42  taken along line  11 - 11  of  FIG. 10A  is shown in  FIG. 12 . The lower cap portion  42   b  of the first cap element  42  includes an inside female thread T 1  for cooperating with the upper male threaded end  38   a  of the body element  38  for assembling the roll-over valves  30 . The thread T 1  is preferably a one half by 24 thread. An upper cap portion  42   a  includes a port  43   a  connecting the vent tube  12  to ambient air pressure. The port  43   a  reached upward and then turns down to an angle A 2  below horizontal, the angle A 2  preferably approximately 30 degrees. The port  43   a  has an inside diameter D 1 , the diameter D 1  preferably approximately 0.218 inches. A frusto-conical base portion  42   c  connects the port  43   a  to the lower cap portion  42   b . The frusto-conical base portion  42   c  having an angle A 1 , the angle A 1  preferably approximately 35 degrees from vertical. 
         [0057]    A front view of a second cap element  50  of the roll-over valve  30  according to the present invention is shown in  FIG. 13A , a top view of the second cap element  50  is shown in  FIG. 13B , and a cross-sectional view of the second cap element  50  taken along line  14 - 14  of  FIG. 13A  is shown in  FIG. 14 . The second cap element  50  has a port  43   b  having a vertical portion like the port  43   a  but replacing the downward sloping portion with a horizontal portion. The second cap element  50  is otherwise like the first cap element  42   
         [0058]    A front view of a third cap element  52  of the roll-over valve  30  according to the present invention is shown in  FIG. 15A , a top view of the second cap element  52  is shown in  FIG. 15B , and a cross-sectional view of the third cap element  52  taken along line  16 - 16  of  FIG. 15A  is shown in  FIG. 16 . The third cap element  52  has a port  43   c  having a vertical portion like the port  43   a  but the vertical portion continues through the top of the third cap element  52 . The third cap element  52  is otherwise like the first cap element  42 . A roll-over valve including the third cap element  52  is suitable for most racing uses. 
         [0059]    A front view of a fourth cap element  54  of the roll-over valve  30  according to the present invention is shown in  FIG. 17A , a top view of the fourth cap element  54  is shown in  FIG. 17B , and a cross-sectional view of the fourth cap element  54  taken along line  18 - 18  of  FIG. 17A  is shown in  FIG. 18 . The fourth cap element  54  has a port  43   d  having a vertical portion like the port  43   a  but the vertical portion continues above the top of the fourth cap element  54  into a barbed hose fitting. The fourth cap element  54  is otherwise like the first cap element  42 . A roll-over valve including the fourth cap element  54  is suitable for race boats and off-road racing uses where safety requirements require that a tube be connected to the vent tube  12  (see  FIG. 1A ) to carry any escaping fuel to a holding tank. The fourth cap element  54  provides the barbed hose fitting for connection of the tube to meet the safety requirements. 
         [0060]    A second carburetor  10 ′ with a choke housing  60  above the primary side of the carburetor is shown in  FIG. 19 . The normal float bowl vent  12  is present on the secondary side of the carburetor  10 ′, but not on the primary side where an integral float bowl vent  62  is formed as part of the choke housing  60 . In one embodiment, a float bowl vent extension  64  is attached inside the integral float bowl vent  62 , for example, by high strength epoxy. A second roll-over valve  30 ′ may then be attached to the float bowl vent extension  64  using a compression fitting. In another embodiment, the choke housing  60  may be machined to allow the roll-over valve  30  to reside directly over the integral float bowl vent  62 . 
         [0061]    While a roll-over valve is described above attached using a compression fitting, in some cases, space may be limited, and a shorter roll-over valve may be attached by forming threads on the outside of the float bowl vent, or by high strength epoxy, and any rollover valve having the ball check structure described above and connected serially with the vent tube, wherein all of the flow through the vent tube is restricted to also pass through the roll-over valve, is intended to come within the scope of the present invention. 
         [0062]    In some applications requirements exist that the vent tube  12  be connected to an opposite vent tube  12 , or to another structure, and the barbed end of the fourth cap element  54  is provided for such applications. 
         [0063]    The roll-over valve  30  may be made from metal or a high strength plastic, and is preferably made from brass. 
         [0064]    While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.