Abstract:
A skull-shaped air filter housing comprising a housing removably attached to a fitting. A jaw is hingedly attached along a lower edge of a face on the housing. The face has eye intake(s), a nose intake, and a jaw intake. When the jaw is open, air enters a housing cavity through the jaw intake. Means of rotating the jaw are disclosed, including cable actuation, spring biasing, and pneumatic actuators. The housing may contain a light for aesthetic purposes. The fitting may incorporate a fitting lumen diameter reduction at its intake to cool and compress air sent to the carburetor. When ram air enters the skull-shaped air filter housing and is sent to the carburetor, it is compressed and therefore denser, and fuel in the carburetor bowl is also compressed, resulting in a power increase in the engine.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to air filters for engines, and in particular to a skull-shaped air filter housing. 
     2. Background of the Invention 
     Air filters serve an important function in internal combustion engines, in that they help prevent entry of dust and other particulate matter into the sensitive carburetion systems of these engines. Even a small amount of dirt or dust can foul and plug the small jets in carburetors, causing their malfunction and even failure. 
     Motorcycles typically have an air filter mounted on the side of the motorcycle. The air filter in these installations is often connected to the motorcycle carburetor by means of a 90 degree fitting, which allows the longitudinal axis of the air filter to align with the airflow. 
     One problem with current motorcycle air filter installations is the lack of a housing to capture ram air and pressurize the air filter. The advantage to pressurizing the air into the carburetor is denser air, as well as slightly pressurized fuel due to ram air pressure on the carburetor bowl, which translates into higher horsepower output from the engine. The engine thinks it&#39;s at a lower density altitude than it actually is, and performs better. This happens because the air is denser, so there are more molecules of oxygen per cubic foot for the engine to burn. 
     Thus, it would be desirable to provide an air filter housing which captures ram air pressure when the motorcycle is at speed, and uses the ram air pressure to pressurize the air and fuel going into the carburetor in order to extract greater power from the engine. 
     Another problem with currently available motorcycle air filter installations is the lack of aesthetic appeal of a raw air filter mounted to the side of the motorcycle. Thus, it would be desirable to provide an air filter housing which is aesthetically pleasing. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a skull-shaped air filter housing which captures ram air pressure when the motorcycle is at speed, and uses the ram air pressure to pressurize the air and fuel going into the carburetor in order to extract greater power from the engine. Design features allowing this object to be accomplished include a housing having eye intakes, a nose intake, and a jaw intake. Advantages associated with the accomplishment of this object include greater power extracted from the engine, and the speed, performance and safety advantages associated therewith. 
     It is another object of the present invention to provide a skull-shaped air filter housing which is aesthetically pleasing. Design features allowing this object to be accomplished include a housing shaped like a skull, head, or face, be it human, hog, dragon, wolf, tiger, lion, or other type of skull. A benefit associated with the accomplishment of this object is a nicer looking air filter installation. 
     It is still another object of this invention to provide a skull-shaped air filter housing which incorporates a variable sized opening. Design features enabling the accomplishment of this object include a jaw intake covered by a jaw sized and located to cover the jaw intake when the jaw is in a closed position. Advantages associated the realization of this object include the provision of a greater quantity of ram air to the engine when the motorcycle is a speed, and the speed, performance and safety advantages associated therewith. 
     It is yet another object of this invention to provide a skull-shaped air filter housing which is inexpensive to produce. Design features allowing this object to be achieved include the use of components made of readily available materials. Benefits associated with reaching this objective include reduced cost, and hence increased availability. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, together with the other objects, features, aspects and advantages thereof will be more clearly understood from the following in conjunction with the accompanying drawings. 
     Six sheets of drawings are provided. Sheet one contains FIG.  1 . Sheet two contains FIG.  2 . Sheet three contains FIGS. 3 and 4. Sheet four contains FIG.  5 . Sheet five contains FIG.  6 . Sheet six contains FIGS. 7 and 8. 
     FIG. 1 is a front quarter isometric view of a skull-shaped air filter housing. 
     FIG. 2 is a front quarter exploded isometric view of a skull-shaped air filter housing. 
     FIG. 3 is a left side quarter isometric view of an air filter about to be connected to a fitting. 
     FIG. 4 is a right side cross-sectional view of an air filter attached to a fitting. 
     FIG. 5 is left side cross-sectional view of a skull-shaped air filter housing with its jaw in the closed position. 
     FIG. 6 is left side cross-sectional view of a skull-shaped air filter housing with its jaw in the open position. 
     FIG. 7 is a rights side view of a skull-shaped air filter housing. 
     FIG. 8 is a right side cross-sectional view of a fitting. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a front quarter isometric view of skull-shaped air filter housing  2  with jaw  5  in the closed position. FIG. 2 is a front quarter exploded isometric view of skull-shaped air filter housing  2  with jaw  5  in the open position. Skull-shaped air filter housing  2  comprises housing  4  removably attached to fitting  6 . Housing  4  is shaped like a skull, and comprises housing face  9  at its front end, and housing filter aperture  11  at its rear end. Housing cavity  7  sized to accommodate air filter  18  is disposed within housing  4 . 
     Eye intakes  12 , nose intake  14 , and jaw intake  16  are disposed in face  9 . Housing cavity  7  communicates with an exterior of housing cavity  7  through eye intakes  12 , nose intake  14 , and jaw intake  16  disposed in face  9  at the front of housing  4 , and housing filter aperture  11  at the rear of housing  4 . 
     Jaw  5  is hingedly attached to a lower edge of face  9  by means of jaw hinges  8 . When jaw  5  is in the open position as depicted in FIG. 2, ram air is free to flow through jaw intake  16  into housing cavity  7 . When jaw  5  is in the closed position as depicted in FIG. 1, ram air is impeded by jaw  5  from flowing into housing cavity  7  through jaw intake  16 , but rather flows in via eye intake(s)  12  and nose intake  14 . 
     FIG. 3 is a left side quarter isometric view of air filter  18  about to be connected to fitting  6 . FIG. 4 is a right side cross-sectional view of air filter  18  attached to fitting  6 . Fitting  6  comprises fitting lumen  21  which communicates with the exterior of fitting  6  at one end through fitting intake  22 , and at an opposite end through fitting outlet  20 . Fitting intake flange  34  is disposed at the end of fitting  6  at which fitting intake  22  is disposed. Fitting intake flange  34  comprises at least one fitting intake fastener bore  32  through which a fastener removably attaches to housing  4 . In addition, fitting intake flange  34  comprises filter groove  24  sized to admit air filter mouth  19 . Filter nipple  26  is disposed within filter groove  24 , and is sized to fit into air filter mouth  19 . 
     Air filter  18  is removably attached to fitting  6  as depicted in FIGS. 3 and 4. First, housing  4  is detached from fitting  6  by removing fasteners through fitting intake fastener bore(s)  32 . Then hose clamp  35  is placed loosely around air filter mouth  19 , and filter nipple  26  is pressed into air filter mouth  19  as indicated by arrow  30  in FIG.  3 . Then hose clamp  35  is tightened around air filter mouth  19 . If necessary, access may be gained to tighten or loosen hose clamp  35  through hose clamp access notch  28  in fitting intake flange  34 . 
     Housing  4  is then re-attached to fitting  6  using fastener(s)  42  through fitting intake fastener bore(s)  32  as depicted in FIG.  5 . As may be observed in FIG. 7, housing  4  further comprises hose clamp access notch cover  44  sized and located to cover and seal hose clamp access notch  28  when housing  4  is attached to fitting  6 . 
     In the preferred embodiment, fitting  6  comprised a bend of substantially 90 degrees, in order to permit fitting outlet  20  to be mounted to a side-ways facing motorcycle carburetor air intake, and still provide for face  9  to face forward into the relative wind impinging upon the motorcycle when in motion. It is contemplated to fall within the scope if this invention that fitting  6  may incorporate a substantially 90 degree angle, such as in the fitting  6  depicted in FIGS. 1-8, or any other angle, or may be straight, as would be used with some turbo-charged engines. 
     Various means are disclosed to actuate jaw  5 . One reason that it is desirable to provide for actuation of jaw  5  is to provide additional ram air to the motorcycle carburetor as the motorcycle speed increases. Another reason is for aesthetic purposes—it would be desirable to have jaw  5  open automatically as if skull housing  4  was talking when the motorcycle operator revs his engine while stopped at traffic lights, to impress other bikers and passing young ladies, for example. 
     As a motorcycle upon which the instant skull-shaped air filter housing  2  is mounted increases speed, so also does its engine, and the need for air also increases. As the speed of the motorcycle increases, so also does the ram air impinging on jaw  5 . This ram air may be used to open jaw  5  to uncover jaw intake  16  at a pre-determined speed, such as twenty miles per hour. The operator may wish to manually control the position of jaw  5 , and one embodiment providing this capability is illustrated in FIG.  5 . Still another embodiment provides that vacuum pressure from the engine automatically opens and closes jaw  5 . For example, FIG. 6 illustrates one embodiment wherein jaw  5  remains closed when the motorcycle engine is not running or is idling, and when the motorcycle operator revs the engine, jaw  5  opens automatically in response to the changing vacuum. In this embodiment, jaw  5  would open at a pre-determined manifold pressure, such as that corresponding to the motorcycle increasing its speed above twenty miles per hour. 
     Thus, while several jaw actuation embodiments are disclosed herein, it is contemplated to fall within the scope of this invention that any method of actuation of jaw  5  may be used. FIGS. 5 and 6 illustrate a number of these. 
     FIG. 5 is a left side cross-sectional view of skull-shaped air filter housing  2  with its jaw  5  held in the closed position by means of spring  45 . The rotational position of jaw  5  is controlled by cable  46 , which reciprocates within cable sheath  48  as indicated by arrow  50 . An opposite extreme of cable  46  may be mounted to a convenient location on the motorcycle, such as on its side or on its handlebars. The rotational position of jaw  5  may then be manually controlled by the motorcycle operator by extending or retracting cable  46  as desired. In the preferred embodiment, cable  46  and cable sheath  48  were bicycle or motorcycle brake or gear changing cables, and terminated in a handlebar mounted lever such as a bicycle gear change lever. 
     FIG. 5 additionally depicts the possibility of the rotational position of jaw  5  being determined solely be spring  45  in combination with ram air, the aid of without cable  46  and cable sheath  48 . Where only spring  45  is installed, spring  45  is installed under sufficient tension to hold jaw  5  in the closed position against the weight of jaw  5 , when the motorcycle is not in motion. When the motorcycle accelerates to approximately 20 miles per hour, ram air impinging against jaw  5  in combination with the weight of jaw  5  overcome the installed tension of spring  45 , and open jaw  5 . 
     Increasing ram air pressure as the motorcycle continues to accelerate serves to increase the density of air into the carburetor, and also pressurizes fuel in the carburetor bowl, in order to increase the power available from the engine. Thus, when the motorcycle upon which the instant skull-shaped air filter housing  2  is mounted is idling or travelling slowly, jaw  5  covers jaw intake  16 , and air enters housing cavity  7  solely through eye intake(s)  12  and nose intake  14 , as indicated by arrows  36  and  38  respectively. As the motorcycle upon which the instant skull-shaped air filter housing  2  is mounted accelerates and more ram air is required, jaw  5  rotates into the open position, uncovering jaw intake  16 , and additional ram air enters housing cavity  7  as illustrated by arrow  40 . 
     It is important to note that FIG. 5 illustrates two separate, independent means of controlling the position of jaw  5 : spring  45  in isolation, and cable  46  with cable sheath  48  in isolation. Of course, if desired, the two may be used in conjunction. 
     FIG. 6 depicts two additional means of controlling the angular position of jaw  5 , by means of interior jaw bellcrank  60  and exterior jaw bellcrank  58 . Pushrod  52  is attached to the output of a pneumatically actuated device such as one end of bellows  54 , and engine vacuum source  56  is connected to an opposite end of bellows  54 . The engine vacuum source be any appropriate engine vacuum source, such as a carburetor vacuum chamber. The end of pushrod  52  opposite bellows  54  is connected to exterior jaw bellcrank  58  in one embodiment, and to interior jaw bellcrank  60  in another embodiment. Thus, depending on which bellcrank pushrod  52  is connected to, changes in the vacuum pressure will either open or close jaw  5 . In the preferred embodiment, jaw  5  was closed when the engine was not running and when the engine was running at idle, and opened when the speed of the engine was increased, such as would occur when the motorcycle sped up past twenty miles per hour, or when the motorcycle operator revved the engine. 
     Spring  45  could optionally also be used in conjunction with either of the bellows actuated embodiments depicted in FIG.  6 . In addition, it is contemplated to fall within the scope of this disclosure that any vacuum-driven actuator be used to move pushrod  52 . For example, a diaphragm could be used, or a diaphragm/spring combination, or a bellowsphram, etc. 
     Jaw  5  comprises jaw ramp  10 , which is a substantially flat inside upper surface of jaw  5 . Jaw ramp angle  15  is the angle between jaw ramp  10  and the lower surface of skull-shaped air filter housing  2 . As may be noted in FIG. 6, when jaw  5  is in the open position, jaw ramp angle  15  is 30 degrees±15 degrees. It has been established experimentally that a jaw ramp angle  15  of 30 degrees±15 degrees is the optimum jaw ramp angle to most efficiently channel ram air through jaw intake  16  into housing cavity  7 . 
     FIG. 6 also depicts another alternate embodiment of skull-shaped air filter housing  2  wherein light  51  is mounted within housing cavity  7 . Light  51  may be one or more electric lights, or any other appropriate source of illumination. The presence of a light within housing cavity  7 , which shines out from eye intakes  12 , nose intake  14 , and jaw intake  16  when jaw  5  is open, enhances the aesthetic appeal of the instant skull-shaped air filter housing  2 , especially at night. It is contemplated to fall within the scope of this invention that any appropriate type or color light  51  may be used. 
     When a motorcycle upon which skull-shaped air filter housing  2  is mounted is in motion, ram air enters housing cavity  7  through eye intake(s)  12  and nose intake  14  as shown by arrow  36  and  38  respectively in FIGS. 5 and 6. This ram air passes through the air filter  18  and into the carburetor air intake through air filter  18 , housing filter aperture  11 , fitting intake  22 , fitting lumen  21 , and fitting outlet  20 . When jaw  5  is open as depicted in FIG. 6, ram air additionally enters housing cavity  7  through jaw intake  16  as indicated by arrow  40  in FIG.  6 . 
     While the skull depicted in FIGS. 1-8 is a human skull, it is contemplated to fall within the scope of this invention that any skull, head or face be used. Skulls which could be used include, but are not limited to, wolf skulls, dragon skulls, hog skulls, tiger skulls, lion skulls, dinosaur skulls, insect skulls, etc. Heads or faces of the above could be used, or other heads or faces. 
     FIG. 8 is a right side cross-sectional view of an alternate embodiment fitting  6  incorporating a diameter reduction  62  in fitting lumen  21  at fitting intake  22 . This diameter reduction is known as A velocity stack, and serves to cool and compress air going to the carburetor. 
     In the preferred embodiment, housing  4 , fitting  6  and jaw  5  were aluminum, steel, titanium, Synthetic, or any other appropriate metal or other material. Fasteners  42  were off-the-shelf Fasteners, Bellows  54 , pushrod  52 , cable  46 , cable sheath  48 , and spring  45  were commercially available items. 
     While a preferred embodiment of the invention has been illustrated herein, it is to be understood  21  that changes and variations may be made by those skilled in the art without departing from the spirit of the appending claims. 
     Drawing Item Index 
       2  skull-shaped air filter housing 
       4  housing 
       5  jaw 
       6  fitting 
       7  housing cavity 
       8  jaw hinge 
       9  face 
       10  jaw ramp 
       11  housing filter aperture 
       12  eye intake 
       14  nose intake 
       15  jaw ramp angle 
       16  jaw intake 
       18  air filter 
       19  air filter mouth 
       20  fitting outlet 
       21  fitting lumen 
       22  fitting intake 
       24  filter groove 
       26  filter nipple 
       28  hose clamp access notch 
       30  arrow 
       32  fitting intake fastener bore 
       34  fitting intake flange 
       35  hose clamp 
       36  arrow 
       38  arrow 
       40  arrow 
       42  fastener 
       44  hose clamp access notch cover 
       45  spring 
       46  cable 
       48  cable sheath 
       50  arrow 
       51  light 
       52  pushrod 
       54  bellows 
       56  vacuum source 
       58  exterior jaw bellcrank 
       60  interior jaw bellcrank 
       62  diameter reduction