Abstract:
An aerodynamic aid for vehicles, including automobiles, trucks, trains, airplanes and motorcycles. A cylindrical roller is rotatably mounted in the path of airflow over the vehicle&#39;s body. When the air begins to flow, the roller rotates and causes air resistance of the vehicle to change. The roller can increase or decrease air flow through spaces where there is negative pressure.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/666,754 filed Mar. 30, 2005. 
     
    
     STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT  
       [0002]     (Not Applicable)  
       REFERENCE TO AN APPENDIX  
       [0003]     (Not Applicable)  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     This invention relates generally to aerodynamic devices for vehicles, such as automobiles, trucks, airplanes, jets, and any other vehicles that move through air.  
         [0006]     2. Description of the Related Art  
         [0007]     It is known in the field of aerodynamics that “dead spaces” exist behind vehicles that move through air, and such dead spaces contain drag-increasing negative air pressures behind them. Existing devices, such as wings, are used to drive air into dead spaces in order to reduce the drag on the vehicle. As the vehicle moves through the air, the wing directs air into the dead spaces to reduce this negative pressure.  
         [0008]     Wings and other aerodynamic devices are typically stationary, inasmuch as they do not move as the vehicle is moving. Some devices can move as the vehicle is moving, but such devices only move due to their attachment to a part of the vehicle that move, such as suspension components. Thus, as the suspension components move relative to the vehicle body, the aerodynamic device moves. However, this movement is very limited, and is not controlled by wind speed, but suspension movement or some other factor not related to the aerodynamic impact that the device is intended to affect. Alternative devices include wings that raise and lower according to speed of the vehicle, so that as the vehicle&#39;s speed increases, the wing rises to produce more downwardly-directed force to stabilize the vehicle.  
         [0009]     Wings and other aerodynamic devices have disadvantages. Therefore, the need exists for devices that reduce the negative air pressure in dead spaces and otherwise affect the aerodynamic effects, such as by increasing drag, without the attendant disadvantages of wings.  
       BRIEF SUMMARY OF THE INVENTION  
       [0010]     The invention is an aerodynamic apparatus mounted to a vehicle having a vehicle body over which air flow passes during motion of the vehicle. The apparatus comprises a roller rotatably mounted about its axis to the vehicle body and having a radially outwardly facing surface. The radially outwardly facing surface of the roller is disposed near an edge of the vehicle body over which the air flow passes during motion of the vehicle. This permits air that flows over the roller to tend to rotate the roller. Upon rotation, the roller affects the aerodynamic properties of the vehicle. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0011]      FIG. 1  is a side schematic view illustrating a conventional box truck on which an embodiment of the invention is mounted.  
         [0012]      FIG. 2  is a view in perspective illustrating a close-up view of the invention on the  FIG. 1  truck.  
         [0013]      FIG. 3  is a view in perspective illustrating the roller of the  FIG. 1  embodiment.  
         [0014]      FIG. 4  is a view in perspective illustrating an alternative embodiment of the present invention. 
     
    
       [0015]     In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word connected or term similar thereto are often used. They are not limited to direct connection, but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     The truck  8  in  FIG. 1  has a cargo box  10  mounted on a frame, and a cab  12 , as is well known. As the truck moves through the air, it forces the air beside it, above it and below it. That air is pressurized locally due to its displacement by the truck body, and as the truck moves through the air, the air passes back around the rear thereof. However, because the rear of the conventional truck box  10  has an abrupt transition, the air passes over the back edge  20  of the box  10 , rather than conforming exactly to the trailing surface of the box  10 , and would create a low pressure area just below the back edge  20  if it were not for the invention, which will now be described.  
         [0017]     A roller  30  is rotatably mounted to the box  10  with the axis of the roller  30  substantially parallel to the back edge  20 . The roller  30  extends almost the entire width of the box  10 , although the length of the structure can vary, as discussed below. The roller  30  is preferably a circular cylinder made of a lightweight material, such as hollow aluminum, plastic, composite (e.g., fiberglass or carbon fiber) or any other material that will suffice, as will be understood by a person having ordinary skill in the art from the description herein.  
         [0018]     The roller  30  is mounted to the box  10  by a pair of mounting legs  32  and  34  at opposite ends of the roller  30  (mount  34  is not shown). The legs  32  and  34  are substantial mirror images of one another, and function to mount the roller  30  securely to the body to which it is attached. For example, the legs  32  and  34  can be made of lightweight aluminum, and can mount with flanges at the end seating against the box  10 . The ends of the legs that attach to the roller  30  preferably insert into a low-friction ball-bearing assembly  36 , shown in  FIG. 3 . The ball-bearing assembly is conventional and can be press-fit into an aperture at each end of the roller  30 , preferably aligned coaxially with the axis of the roller  30 . Thus, the roller  30  is mounted to the box  10  so that it can rotate freely about its axis, but will not detach from the vehicle until deliberately removed, such as for maintenance or replacement.  
         [0019]     The roller  30  is mounted with its radially outwardly facing surface  38  to near a plane that contains the roof  16  of the box  10 . The surface  38  can be aligned precisely along the plane, thereby aligning the plane along a tangent of the surface  38 , or it can be raised above it or below it. In all cases, however, the surface  38  is aligned along the path of air that flows over the vehicle body, such as the roof  16 , so that at least some of the molecules of air moving over the body impinge more upon one half of the surface  38  than the opposite half. This impingement of the molecules on the surface  38  causes the roller  30  to rotate about its axis. The volume of air molecules that impinge upon the surface  38 , the speed of the air and other factors, which will become apparent to the person having ordinary skill from this description, will affect the acceleration of and the velocity of the roller  30 .  
         [0020]     As the roller  30  rotates, it attains a desired speed, which is preferably equal to, greater than or less than, the speed of the air passing over the vehicle body just upstream of the roller  30 . When the surface  38  rotates substantially the same speed as the air, the resistance that the rotating surface  38  presents to air molecules passing over the box  10  is less than the air molecules would encounter if there was no roller. This is due to the fact that the surface  38  is moving faster than a stationary object. Additionally, the curvature of the roller  30  more gradually directs air around the box  10 . Finally, and very importantly, because the roller  30  is rotating, its outer surface  38  tends to force air behind the box  10  where negative pressure otherwise exists in conventional trucks of the same shape as the truck  8  (without the invention attached thereto).  
         [0021]     In a preferred embodiment, the roller  30  has dimples  39  or concave depressions of any other kind, including elongated concave depressions, such as slots, formed in the curved surface  38  in order to increase the friction between the surface  38  and air molecules passing over the surface  38 . The dimples  39  thus function in the manner of dimples on the outer surface of a conventional golf ball. As another alternative, the roller could have convex bumps that protrude out of the surface of the roller.  
         [0022]     In addition to the roller  30  on the top edge of the box  10 , the roller  40  is preferably mounted to the side edge of the box  10 . The roller  40  is mounted in a manner similar to the roller  30 , but at the side edge of the box  10 , rather than the top edge  20 . Other rollers can be mounted on the other edges of the box  10 , including the bottom and the leading edges, as will be apparent to the person having ordinary skill in the art.  
         [0023]     Thus, the invention is a roller mounted on bearings so that it can rotate very freely. The goal of the invention is to improve the aerodynamic effects of the object moving through the air. In order to achieve that goal, a plurality of such rollers can be strategically mounted on any vehicle trying to move through the air efficiently, including, but not limited to, an automobile, truck, tractor-trailer, train, motorcycle, bicycle or airplane. Rollers are positioned near edges of the vehicles&#39; bodies around which air rushes when the vehicle is in motion, and more of one part of the rollers are exposed to air rushing over the edge of the body than the other. The air causes the rollers to rotate about their axes as more air passes over one edge of the roller than the other.  
         [0024]     The rollers force air into “dead spaces” behind vehicles that otherwise contain drag-increasing negative air pressures. When left to rotate freely, the rollers, as dictated by the laws of physics, tend to rotate at the most efficient speed to reduce drag by filling the negative pressure zones with air, thus reducing the drag on the vehicle. The rollers thus effectively alter the aerodynamic “shape” of the object they are attached to. The rollers adjust their rotating speed to the optimum level to reduce wind resistance. The spinning rollers alter the airflow and improve aerodynamic efficiency.  
         [0025]     The rotation of the rollers can also be controlled to alter their aerodynamic effects to suit certain situations, such as by attaching a motor  50 , as in  FIG. 4 , or brakes to the rollers. The driveshaft of the motor  50  is mounted to the roller  60  either by a rigid connection, or by a “coasting” device, similar to that in a bicycle hub, that prevents the motor  50  from resisting movement of the roller  60  in one direction when such resistance is not desired, but provides a drive link to the roller  60  in the other direction.  
         [0026]     The rollers can thus be artificially slowed to generate drag, thereby slowing a vehicle, or the rollers&#39; speeds can be increased beyond that due to the flow of air in order to generate less drag or more lift, such as for a wing, thereby utilizing an energy source to induce certain effects. Of course, with multiple rollers, different rollers can be affected differently in order to best accomplish the desired result, as in an automobile in which the brakes, accelerator and the rollers of the invention are controlled by a vehicle&#39;s stability control system.  
         [0027]     The roller need not be a circular cylinder. The roller could be octagonal or any other polygonal cylinder. Alternatively, the roller could have a larger diameter in the middle than at the ends, or could be larger at one end than the opposite end, such as with a cone or other tapered shape, as will become apparent to a person having ordinary skill in the art. This allows the roller to be tailored to the particular structure to which it is mounted.  
         [0028]     Still further, the roller can be made up of multiple disks or rotatably-mounted polygons “stacked” together with aligned axes in order to affect airflow around a vehicle. This would permit rotation of one disk relative to another.  
         [0029]     While certain preferred embodiments of the present invention have been disclosed in detail, it is to be understood that various modifications may be adopted without departing from the spirit of the invention or scope of the following claims.