Abstract:
A drag reduction device for a trailer comprising a generally U-shaped upstanding wall means having a floor secured to the lower end thereof. The device is secured to the underside of the trailer so that the rearward end of the device is positioned just forwardly of the forward end of the rear wheel assembly of the trailer. In one embodiment, the device is coupled to the slider axle of the trailer so that the device is moved forwardly and rearwardly with the slider axle.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an aerodynamic drag reduction device for a trailer and more particularly to an aerodynamic drag reduction device which is positioned at the underside of the trailer forwardly of the rear wheel assembly to reduce air flow impingement on the rear wheel assembly. 
     2. Description of the Related Art 
     Typical semi-trailers include a body having a forward end, a rearward end, a first side, a second side and a rear wheel assembly at the underside of the body. As the trailer moves along a highway, air flow impinges on the wheels, axle and suspension system of the rear wheel assembly to create an aerodynamic drag which adversely affects the fuel consumption of the truck or tractor pulling the trailer. 
     Drag reduction devices have been previously provided which attempt to reduce the aerodynamic drag on the rear wheel assembly of trailers. For example, in U.S. Pat. No. 6,974,178, various drag reduction devices are disclosed which attempt to reduce the aerodynamic drag on the rear wheel assembly of a trailer. Although the drag reduction of U.S. Pat. No. 6,974,178 may reduce the aerodynamic drag on the rear wheel assembly of a trailer to some degree, improvements thereof are necessary to further reduce the aerodynamic drag on the rear wheel assembly. The instant invention has been proven to substantially reduce the aerodynamic drag of such trailers. 
     Additionally, to the best of Applicant&#39;s knowledge, the aerodynamic drag reduction devices of the prior art do not perform satisfactorily when the trailer rear wheel assembly is of the sliding axle type. 
     SUMMARY OF THE INVENTION 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter. 
     An apparatus is provided for reducing the aerodynamic drag of a trailer having a body with a forward end, a rearward end, opposite sides, an underside and a rear wheel assembly supporting the body from the underside thereof. The drag reduction device of this invention includes a generally U-shaped upstanding air deflector wall means having a forward end and a rearward end. The wall means includes a first side portion having a rearward end, a forward end, an upper end and a lower end. The first side wall portion of the wall means extends forwardly and inwardly in a generally curved manner from its rearward end to its forward end. The wall means includes a second side wall portion having a rearward end, a forward end, an upper end and a lower end. The second side wall portion of the wall means extends forwardly and inwardly in a generally curved manner from its rearward end to its forward end. The forward ends of the first and second wall portions are joined together to form a round nose portion. A horizontally extending floor, having forward and rearward ends, is secured to the lower ends of the first and second side wall portions and extends therebetween. 
     The device of this invention is positioned beneath the underside of the trailer so that the rearward ends of the first and second side wall portions of the wall means are positioned adjacent the forward end of the rear wheel assembly whereby air flow impinging on the wall means will be deflected outwardly of the rear wheel assembly. In the preferred embodiment, the floor includes portions thereof which extend outwardly from the first and second side wall portions and the nose portion of the wall means. 
     If the trailer includes a sliding axle, the device of this invention is operatively secured to the sliding axle for longitudinal movement therewith. 
     The apparatus of this invention may also include side shield assemblies which are operatively secured to the trailer which extend rearwardly from the rearward ends of the first and second side wall portions of the wall means. 
     It is a principal object of the invention to provide an aerodynamic drag reduction device for a trailer. 
     A further object of the invention is to provide an aerodynamic drag reduction device for a trailer which is positioned at the underside of the trailer forwardly of the rear wheel assembly thereof to prevent air from impinging on the rear wheel assembly of the trailer. 
     A further object of the invention is to provide an aerodynamic drag reduction device for a trailer which is positioned at the underside of the trailer and which is operatively secured to the sliding axle of the trailer for longitudinal movement therewith. 
     A further object of the invention is to provide an aerodynamic drag reduction device for a trailer which is generally U-shaped and which includes a floor with the floor having portions thereof which extend outwardly from the forward end and sides of the device. 
     A further object of the invention is to provide an aerodynamic drag reduction device for a trailer which may be retrofitted onto existing trailers. 
     These and other objects will be apparent to those skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG. 1  is a perspective view of the aerodynamic drag reduction device of this invention secured to the underside of the trailer which is partially shown; 
         FIG. 2  is a perspective view of the aerodynamic drag reduction device of this invention; 
         FIG. 3  is a top view of a drag reduction device mounted on the underside of a trailer; 
         FIG. 4  is a partial view of a trailer having a slider axle mounted thereon with the slider axle and the drag reduction device in its forward position; 
         FIG. 5  is a view similar to  FIG. 4  except that the slider axle and drag reduction device have been moved rearwardly from the position of  FIG. 4 ; and 
         FIG. 6  is a side view illustrating the slider axle in its rearward position and the drag reduction device of this invention having been moved therewith. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments are described more fully below with reference to the accompanying figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense in that the scope of the present invention is defined only by the appended claims. 
     The numeral  10  refers to a conventional semi-trailer having an underside generally referred to by the reference numeral  12 . Trailer  10  includes a rear trailer wheel assembly  14  which is normally of the tandem axle type although the rear trailer wheel assembly could be of the single axle style. The rear trailer wheel assembly  14  may be fixed to the frame of the trailer or may be slidably longitudinally mounted on the frame of the trailer such as illustrated in  FIGS. 4-6 . As seen in  FIGS. 4-6 , the rear trailer wheel assembly includes a slider assembly  16  which is slidably movably mounted on the trailer frame means  18 . 
     The numeral  20  refers to the drag reduction device of this invention which is either attached to the underside  12  of the trailer  10  forwardly of the rear trailer wheel assembly  14  as seen in  FIG. 1  or is attached to the forward end of the slider assembly  16  for movement therewith as seen in  FIGS. 4-6 . For purposes of description, device  20  will be described as having a forward end  22  and a rearward end  24 . Device  20  includes a first upstanding side wall portion  26  which extends forwardly and inwardly from the rearward end  24  of the device  20  to the forward end  22  of the device  20 . Device  20  also includes a second upstanding side wall portion  28  which extends forwardly and inwardly from the rearward end  24  of the device  20 . The forward ends of side wall portions  26  and  28  are joined together at a rounded nose portion  30 . The side wall portions  26  and  28  may be comprised of wall sections joined together or may be of one-piece construction. 
     Device  20  also includes a floor  32  which is secured to the lower ends of wall portions  26  and  28  and extends therebetween. Floor  32  is designed so that a floor portion  34  extends horizontally outwardly from side wall portion  26  and so that a floor portion  36  extends horizontally outwardly from side wall portion  28  and so that a floor portion  38  extends horizontally outwardly from nose portion  30 . As seen in  FIG. 3 , the width of floor portion  34  gradually increases from its rearward end to its forward end and that the width of floor portion  36  gradually increases from its rearward end to its forward end. As seen in  FIG. 2 , the forward end of floor portion  38  is rounded. 
     A plurality of vertically disposed supports  40  are secured to floor  32  and extend upwardly therefrom. If the device  20  is being used on a trailer which does not have a sliding axle or slider assembly, the upper ends of supports  40  will be secured to the underside of the trailer so that the rearward end  24  of the device  20  is positioned closely to the forward side of the rear wheel assembly  14 . If the device  20  is being used with a trailer which has a slider assembly, the device  20  will be secured to the slider assembly by any convenient means for longitudinal movement therewith the rearward end  24  of the device  20  being closely positioned adjacent the forward end of the wheel assembly  14 .  FIG. 4  illustrates the slider assembly  16  in a forward position while  FIGS. 5 and 6  illustrate the slider assembly  16  in a rearward position. 
     It is preferred that a side shield assembly  42  is secured to the trailer  10  at each of the sides of the wheel assembly  14  to prevent air from impinging on the wheel assembly  14 . If the trailer  10  does not have a slider assembly  16 , the upper ends of the side shield assemblies  42  will be secured to the underside of the trailer  10 . If the trailer has a slider assembly, the side shield assemblies will be secured to the slider assembly for longitudinal movement therewith. It is preferred that the side shield assemblies  42  at the device  20  be constructed of an aluminum material or plastic material. 
     In operation, as the trailer is being pulled over a highway or the like, the air flow at the underside of the trailer will impinge on the device  20  so that the air flow is directed outwardly and rearwardly to prevent the air flow from impinging on the wheel assembly  14  thereby decreasing the aerodynamic drag which would otherwise be experienced. As the air flow strikes the forward ends of side wall portions  26  and  28  and to nose portion  30 , some of the air flow will be directed downwardly therefrom. However, the floor portions  34 ,  36  and  38  prevent the air flow from passing downwardly from those floor portions and will cause the downwardly air flow to be deflected rearwardly along the sides of the side wall portions  26  and  28 . 
     The device  20  reduces the aerodynamic drag of the trailer  10  and therefore accomplishes at least all of its stated objectives. 
     Although the invention has been described in language that is specific to certain structures and methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and/or steps described. Rather, the specific aspects and steps are described as forms of implementing the claimed invention. Since many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.