Abstract:
A tractor-trailer fairing for blocking cross-winds is inexpensive, attaches to a forward face of the trailer, is adjustable to the gap between the tractor and trailer, and is easily moved between trailers. The fairing comprises two pairs of identical upper and lower curved panels independently attached to opposing front corners of the trailer. The panels slide down over pins attached to brackets permanently mounted to the trailer. Pairs of adjustable diagonal struts reach from a forward face of the trailer to each of the curved panels to hold the panels in position. Flaps attach to the forward edges of the panels at about a 90 degree angle and restricts the cross-winds from passing between the panels and tractor cab.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to reducing aerodynamic drag on tractor-trailer rigs and in particular to reducing drag created by the interaction of cross-winds with a gap between the tractor and trailer. 
     Tractor-trailer rigs (or semi-trailers) are a vital element of product distribution. In the United Sates, tractor-trailer rigs travel over 100 billion miles a year consuming over 20 billion gallons of diesel fuel. It has been estimated that almost 65 percent of the fuel burned is to overcome aerodynamic drag. As a result, even a small reduction in aerodynamic drag may have a significant impact on the demand for diesel fuel reducing the cost of shipping products. Additionally, a reduction in demand results in a lower price for diesel fuel, further reducing costs of all diesel fuel consumers. 
     Many attempts have been made to reduce the aerodynamic drag of tractor-trailer rigs. Generally, these attempts are directed to drag created by the motion of the tractor-trailer rigs through the ambient air. For example, sloped tops, side extender fairings and side skirt bottoms have been added to the tractors. However, feasible side extender fairings and side skirt bottoms cannot reach rearward to the trailer because they would interfere with turning without complicated mechanical apparatus for retracting the skirts. Extended side fairings also block access to hoses and cables attached to the back of the tractor cab and to the front of the trailer, making safety inspections difficult, and also block access to access doors on the front of the trailer if so equipped. 
     Some fairings are attached to the tractor such as disclosed in U.S. Pat. Nos. 2,863,695, 3,241,876,3,348,873, 4,458,937, 5,078,448, and others. Unfortunately these fairings are overly complex, expensive, and/or fail to address drag due to cross-winds. 
     For over 50 years it has been known cross-winds contribute to total drag. Other patents address the drag created by cross-winds, including U.S. Pat. No. 7,073,845, for “Aerodynamic Drag Reduction Apparatus for Gap-Divided Bluff Bodies Such as Tractor-Trailers” discloses flat vertical panels attached to the leading face of the trailer and overlapping with flat vertical panels attached to the trailing face of the tractor. While the fairings of the &#39;845 patent address cross-winds, they require precise fitting to the individual tractor and trailer and may interfere with pneumatic hoses and electrical cables connecting the braking, lighting, and refrigeration systems on the tractor-trailer. 
     Another patent, U.S. Pat. No. 7,604,284 for “Vehicle Fairing Structure” discloses a fairing attached to the leading edges of the trailer to direct air away from the gap between the tractor and trailer. The fairing of the &#39;284 patent is fixed to the trailer and not adjustable. It is not easily transferred between trailers and generally a separate fairing is required for each trailer, and it cannot be adjusted when the fifth wheel is moved forward or backwards based on weight distribution. 
     While known fairings provide some benefit, they are overly complex, expensive, and/or require custom fitting, and a need remains for a simple low cost fairing providing reductions in drag to reduce fuel consumption. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention addresses the above and other needs by providing a tractor-trailer fairing for blocking cross-winds, which fairing is inexpensive, attaches to a forward face of the trailer, is adjustable to the gap between the tractor and trailer, and is easily moved between trailers. The fairing comprises two pairs of identical upper and lower curved panels independently attached to opposing front corners of the trailer. The panels slide down over pins attached to brackets permanently mounted to the trailer. Pairs of adjustable diagonal struts reach from a forward face of the trailer to each of the curved panels to hold the panels in position. Flaps attach to the forward edges of the panels at about a 90 degree angle and restricts the cross-winds from passing between the panels and tractor cab. 
     In accordance with one aspect of the invention, there are provided two pairs of vertically spaced panels blocking the flow of cross-winds between a tractor and trailer. Each panel is light weight preferably weighing between 20 and 25 pounds each allowing easy handling by a single individual and low cost shipping. 
     In accordance with another aspect of the invention, there are provided curved panels blocking the flow of cross-winds between a tractor and trailer. Each panel is attached to the trailer and curves inward as the panels reach towards the tractor. The inward curve allows greater clearance then the tractor turns. 
     In accordance with yet another aspect of the invention, there are provided panels having flexible flaps along forward edges of the panels blocking the flow of cross-winds between the tractor and trailer. The flexible flaps are preferably between eight inches and twelve inches wide and attached approximately 90 degrees to the forward edge of the panels and fill gaps between the panels and side extenders attached to the tractor cab. The flexible flaps are sufficiently stiff to block the flow of cross-winds between the tractor and trailer and are sufficiently flexible to bend if they come in contact with the side extenders, exhaust stacks, or other structure attached to the tractor. 
     In accordance with still another aspect of the invention, there are provided removable panels blocking the flow of cross-winds between a tractor and trailer. Each panel pivots at an end attached to a bracket attached to the trailer. The bracket includes a pin and the panels include a boss which slides over the pin. The brackets are simple and low cost and are permanently mounted trailers and the panels are easily removed and moved between trailers as desired. 
     In accordance with still another aspect of the invention, there are provided adjustable panels blocking the flow of cross-winds between a tractor and trailer. Adjustable struts are attached between the forward face of the trailer and the panels. The struts may be adjusted by threaded engagement of strut ends, or by telescoping ends using pins to fix the overall length of each strut, or attached by any apparatus allowing the length of the struts to be adjusted. Using pins to adjust the strut length is particularly advantageous by allowing quick adjustment where irregular surfaces cause large angular deflections between the tractor and trailer, or if weight on the axles needs to be adjusted the fifth wheel can be moved and the panels can be adjusted to provide the proper clearance gap between the tractor and trailer. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       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: 
         FIG. 1A  is side view of a tractor and trailer. 
         FIG. 1B  is a top view of the tractor and trailer. 
         FIG. 2A  is a side view of the tractor and trailer with cross-wind air foils according to the present invention. 
         FIG. 2B  is a top view of the tractor and trailer with the cross-wind air foils according to the present invention. 
         FIG. 3A  is a more detailed top view of the cross-wind air foils according to the present invention. 
         FIG. 3B  is a more detailed outside view of the cross-wind air foils according to the present invention. 
         FIG. 3C  is a more detailed inside view of the cross-wind air foils according to the present invention. 
         FIG. 4A  is a detailed inside view of a panel according to the present invention. 
         FIG. 4B  is an top view of the panel according to the present invention. 
         FIG. 5  shows a panel boss and panel mounting bracket according to the present invention. 
         FIG. 5A  shows a cross-sectional view of the panel boss according to the present invention taken along line  5 A- 5 A of  FIG. 5 . 
         FIG. 6A  shows a fixed length strut according to the present invention. 
         FIG. 6B  shows a threaded adjustable length strut according to the present invention. 
         FIG. 6C  shows a telescoping adjustable length strut according to the present invention. 
         FIG. 7  shows a trailer end of the strut according to the present invention. 
         FIG. 8A  shows a panel end of the strut according to the present invention attached to the panel by a bolt. 
         FIG. 8B  shows a panel end of the strut according to the present invention attached to the panel by a pin and clip. 
         FIG. 9  shows a panel adjusted for a sharp turn according to the present invention. 
         FIG. 10  shows an adjustable trailer plate. 
         FIG. 11A  is a side view of the tractor and trailer with cross-wind air foils and bridging panel according to the present invention. 
         FIG. 11B  is a top view of the tractor and trailer with the cross-wind air foils and the bridging panel according to the present invention. 
     
    
    
     Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
     A side view of a tractor  10  and trailer  12  is shown in  FIG. 1A  and a top view of the tractor  10  and trailer  12  is shown in  FIG. 1B . A gap  14  exists between the tractor  10  and trailer  12  and a drag on the tractor  10  and trailer  12  is created when a cross-wind  20  is present. Air lines and electrical cables  16  supported by lines  18  reside in the gap  14  and connect the tractor  10  and trailer  12 . 
     A side view of the tractor  10  and trailer  12  with cross-wind air foils according to the present invention comprising upper right and left panels  22   a  and lower right and left panels  22   b  are shown in  FIG. 2A , and a top view of the tractor  10  and trailer  12  with the cross-wind air foils is shown in  FIG. 2B . The cross-wind air foils block the cross-wind  20  to reduce drag and improve fuel efficiency of the tractor  10  and trailer  12 . The panels  22   a  and  22   b  are held in position by struts  26  and include flaps  24  at forward ends which cooperate with side extenders  21  attached to the tractor  10  to provide improved blocking of the cross-wind  20 . 
     A more detailed top view of the cross-wind air foils according to the present invention is shown in  FIG. 3A , a more detailed outside view of the cross-wind air foils is shown in  FIG. 3B , and a more detailed inside view of the cross-wind air foils is shown in  FIG. 3C . The panels  22   a  and  22   b  are pivotally attached to a forward face  12   a  of the trailer  12  near corners  12   b  of the forward face  12   a . Panel bosses  32  of the panels  22   a  and  22   b  slide over pins  34  (also see  FIG. 5 ) to pivotally attach the panels  22   a ,  22   b  to the trailer  12 . The strut  26  includes a first clevis  40   a  pivotally attached to the strut boss  28  on the panels  22   a ,  22   b  and a second clevis  40   b  at an opposite end of the strut  26  pivotally attached to a clevis bracket  30  attached to the forward face  12   a  of the trailer  12 . 
     Each panel  22   a  and  22   b  preferably includes two strut bosses  28  vertically positioned on the panel body  23  about one third of the panel height from the top and bottom of the panel respectively. The panels  22   a ,  22   b  are thus interchangeable from right to left and upper to lower. The strut  26  attached to the lower panel is generally attached using the lower strut boss  28  to allow easier access to the strut  26  for installation of the panels or adjustment of the panels. 
     A detailed inside view of the panels  22   a  and  22   b  according to the present invention is shown in  FIG. 4A  and an top view of the panels  22   a  and  22   b  is shown in  FIG. 4B . The panels  22   a  and  22   b  include a panel body  23  preferably made from metal or plastic and more preferably made from plastic. The panels  22   a  and  22   b  may be formed by injection molding, rotational molding, blow molding, or the like, and preferably formed by rotational molding. Dimples  36  on the inside surface  23   a  of the panel body  23  reach to the outside surface  23   b  and add strength to the body  23 . Additionally or alternatively, the body  23  may be foam filled. 
     The panels have a height H, a length L 1 , and a width (or thickness) W. The height H is preferably approximately 46 inches, the length L 1  is preferably between approximately 36 inches and 48 inches, and the width W is preferably approximately five inches. The panels  22   a  and  22   b  are arced at between a 2.5 and 3 foot radius, with a smaller panel having a length L 1  of approximately 36 inches arced over the entire length of the panel, and a larger panel larger having a length L 1  of approximately 48 inches with an arced portion approximately 36 inches long followed by a straight portion approximately 12 inches long. Other panels may include an arced portion approximately 36 inches long followed by a straight portion between 1 and 12 inches long. 
     Flexible flaps  24  are attached to the forward end of the panels  22   a  and  22   b . The flexible flaps  24  are at an angle A 2  to the outer surface  23   b  of the panel body  23 , where the angle A 2  is preferably approximately 92 degrees. The flexible flaps  24  have approximately the same height H as the panel bodies  23  and have a length L 2 . The length L 2  is preferably between approximately eight inches and approximately 12 inches. The flexible flaps  24  are preferably made from a hard rubber or other flexible material and are preferably attached to the panel bodies  23  by bolts but may be attached by any suitable means. The flexible flaps  24  may be positioned closer to the side extenders  21  without risk of damage because the flexible flaps  24  are somewhat flexible, and thereby improve the blocking of cross-winds  20  through the gap  14  (see  FIG. 1   b ). The flexible flaps  24  are of particular value when the cross-winds and coming from near 90 degrees to the direction of the tractor and trailer to the rear of the trailer especially when wind velocities are in the category of 17 mph and above. 
     A panel boss  32  and panel mounting bracket  33  according to the present invention is shown attached to the forward face  12   a  of the trailer  12  in  FIG. 5  and a cross-sectional view of the panel boss  32  taken along line  5 A- 5 A of  FIG. 5  is shown in  FIG. 5A . Preferably, two brackets  33  are provided for each panel  22   a  and  22   b . The vertical pin  34  is attached to the bracket  33  and the boss  32  slides down over the pin  34  to pivotally mount the panels  22   a  and  22   b  to the trailer  12 . A clip  37  is insertable through a clip passage  37   a  to retain the panels  22   a  and  22   b  on the brackets  33 . 
     A liner  31  is molded into the panel boss  32 . The liner  31  comprises a tubular body  31   a  and projections  31   b . The tubular body has a bore which slides over the pins  34  and the projections  31   b  help fix the position of the liner  31  in the boss  32 . The projections  31   b  may be a variety of shapes and preferably have a polygonal cross-section and more preferably a hexagonal cross-section, and preferably has shared off top and bottom shoulders to better hold position in the boss  32 . The liner  31  reinforces the boss  32  to facilitate attachment and separation from trailers without damaging the bosses  32 . 
     Not all truck routes experience significant cross-winds so the air foil according to the present invention is not needed on all trailers at all times. The brackets  33  may be permanently attached to several trailers and the panels  22   a  and  22   b  may be swapped between trailers as needed. The simple attachment described above facilitates such swapping and reduces or eliminates the need to have a set of panels for each trailer. 
     A fixed length strut  26  according to the present invention is shown in  FIG. 6A , a threaded adjustable length strut  26   a  according to the present invention is shown in  FIG. 6B , and a telescoping adjustable length strut  26   b  according to the present invention is shown in  FIG. 6C . The struts  26 ,  26   a , and  26   b  include clevises  40   a  and  40   b  at each end for pivotal attachment to the panels  22   a  and  22   b , and the forward face  12   a  of the trailer  12 . The adjustable strut  26   a  comprises threaded inner and outer strut members  42   a  and  41   a  and a nut  44  for tightening to hold a desired length. The adjustable strut  26   b  includes telescoping drilled inner and outer strut members  42   b  and  41   b  and a clip  37  insertable through aligned passages  46   a  and  46   b  to hold a desired length. 
     A trailer  12  end of the strut  26  is shown in  FIG. 7  with an example of the clevis bracket  30 . A short length of channel  50  is attached to the forward face  12   a  of the trailer  12 . A bolt  54  passes through the clevis bracket  30 , past lips  50   a  and into a captive threaded bar  52 . The bolt  54  is tightened to attach the clevis bracket  30  to the channel  50 . The channel  50  is merely an example of a method for attaching the strut  26  to the trailer  12 , and an air foil according to the present invention utilizing any means for attaching the strut  26  to the trailer  12  is intended to come within the scope of the present invention. 
     A panel end of the strut  26  pivotally attached to the panel boss  28  by a bolt  56  is shown in  FIG. 8A  and a panel end of the strut  26  pivotally attached to the panel boss by a pin  58  is shown in  FIG. 8B . The pin  58  is held in place by the clip  37 , and the strut  26  may be detached from the panel  22   a  or  22   b  very easily by merely pulling the clip  37  from the pin  58  and then removing the pin  58 . The pin  58  and clip  37  are merely one example of a method for attaching the strut  26  to the panel  26 , and an air foil according to the present invention utilizing any means for easily releaseably attaching the strut  26  to the panel  26  without tools is intended to come within the scope of the present invention. 
     A panel  22  is shown adjusted for a sharp turn in  FIG. 9 . The attachment of the strut  26  to the panel  22  shown in  FIG. 8B  and the adjustable struts  26   a  and  26   b  shown in  FIGS. 6B and 6C  allow an operator to easily release the strut from the panel, adjust the length of the strut, and reattach the strut. Such easy adjustment is important because tractor and trailer rigs are often required to make sharp maneuvers in yards, and making such adjustments quickly is important in meeting schedules. 
     A tractor  10  having an adjustable trailer plate  60  is shown in  FIG. 10 . The trailer plate  60  must often be adjusted forward or rearward based on the tongue weight of the trailer  12 . When the trailer  12  is moved closer to the tractor  10 , the panels  22   a  and  22   b  must be adjusted to provide clearance. The adjustable struts  26   a  and  26   b  allow for such adjustment. 
     A side view of the tractor  10  and trailer  12  with panels  22   a  and  22   b  and bridging panel  70  according to the present invention is shown in  FIG. 11A  and a top view of the tractor  10  and trailer  12  with the cross-wind air foils  22   a  and  22   b  and the bridging panel  70  is shown in  FIG. 11B . While tractors  10  often have roof air foils  11  (see  FIGS. 1A and 1B ) mounted to the roof of the tractor  10  to deflect an air flow from the forward face  12   a  of the trailer  12 , in some instances such air foils  11  are not easily attached to the tractors  10  and increased wind resistance results. In such instances a bridging panel  70  may be attached to top forward edges of the right and left panels  22   a , sloping forward and downward, and filling in the gap  14  between the forward edges of the panels  22   a . The bridging panel  70  reaches vertically from a height proximal to the roof  10   a  of the tractor  10  to a second height proximal to the top  12   c  of the trailer  12 . A bridge panel  70  so attached provides the benefit of the roof air foil  11 . The bridge panel  70  comprises three sections, a trapezoidal flat forward face, and triangular two side faces. The bridge panel  70  may be constructed from sheet metal or molded from plastic, having construction similar to the panels  22   a  and  22   b.    
     The panels are preferably adjusted to provide at least approximately eight inches of clearance between the flaps and the stacks, side extenders, or other structure to avoid contact during turns. 
     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.