Abstract:
An aerodynamic panel assembly with surface macrostructure is provided for a land vehicle. The panel assembly includes a first plurality of slats each having a longitudinal length greater than its width, and a second plurality of slats each having a longitudinal length greater than its width. The first and second plurality of slats are interwoven, thereby providing significant structural strength while increasing the versatility of the panel assembly to be used on various types of vehicles. Various types of attachment mechanisms are provided for attaching a panel assembly to the vehicle.

Description:
FIELD OF THE INVENTION 
     The present invention relates to aerodynamic and protective devices for land vehicles. More particularly, the invention is related to a structural panel assembly with a surface macrostructure for reducing aerodynamic drag and improved protection of damage-prone regions of the vehicle, such as the underbody. 
     BACKGROUND OF THE INVENTION 
     Various types of aerodynamic panels have been devised for reducing vehicle drag, including panels which are generally positioned on the underside of the vehicle. Newly manufactured high performance vehicles, for example, commonly use cowlings or panels manufactured from a unitary sheet to reduce the air drag under a vehicle. These same panels cannot be easily modified, however, to fit older vehicles. Moreover, these panels may encounter rocks or other objects when the vehicle is driving at a high rate of speed, and the panels frequently crack or tear, so that new panels are required. 
     Various types of aerodynamic surfaces have also been devised for reducing drag in turbulent flow. U.S. Pat. No. 7,041,363 discloses a microstructured surface in a solid body to reduce frictional or flow resistance when a gas or liquid flows over the object. The surface geometry of an object, i.e. the dimples on a golf ball, can influence the fluid dynamics for the object in relative motion to a fluid. Rough surfaces known in the art can improve turbulent airflow by affecting the boundary layer flow, or flow structures like large eddies and vortices. The aerodynamic benefits of integral rough surfaces are compromised however by the added manufacturing costs of machining patterns such as wavelets and diamonds as disclosed in U.S. Pat. No. 5,114,099. 
     While the benefits of aerodynamic panels on the undersides of vehicles has been thoroughly demonstrated to reduce drag and improve gas mileage, a low percentage of vehicles presently use such panels in an effective manner. As indicated previously, the panels currently installed on high performance vehicles cannot be easily modified or adapted to other vehicles. The need thus exists for a low-cost aerodynamic panel which has broad utility and may be added to existing vehicles. 
     The disadvantages of the prior art are overcome by the present invention, an improved aerodynamic panel assembly and method are hereinafter disclosed. 
     SUMMARY OF THE INVENTION 
     An aerodynamic and protective panel assembly is provided for a land vehicle comprising of a plurality of overlapping slats forming a non-smooth woven surface macrostructure exposed to a fluid, such as air, having relative motion to the vehicle or device. The aerodynamic protection device includes overlapping slats each extending across the width of one or more slats, whereby slats are preferably arranged in a pattern configuration with each slat having a substantially rectangular profile. Additional types and variations of slats discussed herein provide further functionality and benefits. 
     Also provided is an improved method for constructing similar panel assemblies or components thereof in order to achieve, for example, additional aerodynamic or protective benefits, such as controlling the fluid flow or improving mechanical properties. The construction method described herein is an improved construction method for aerodynamic and protective devices for land vehicles whereby a plurality of slats are overlapped and assembled to form a more aerodynamic or durable device. 
     Further features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a right elevation view of a tractor-trailer road vehicle showing the front of the panel assembly mounted to the lower side of the vehicle. 
         FIG. 2  is a pictorial view of the mounted panel assembly shown in  FIG. 1 . 
         FIG. 3  is a front view of the panel assembly shown in  FIG. 1 . 
         FIG. 4  is a pictorial view of the exterior side of the shaped panel assembly shown mounted to the underbody of a road vehicle. 
         FIG. 5  is a pictorial view of the interior side of the shaped panel assembly shown in  FIG. 4 . 
         FIG. 6  is a pictorial view of a standard slat. 
         FIG. 7  is a side view of the standard slat shown in  FIG. 6 . 
         FIG. 8  is a top view of the standard slat shown in  FIG. 6 . 
         FIG. 9  is a pictorial view of a standard panel assembly with a plurality of interwoven  FIG. 6  slats. 
         FIG. 10  is a top view of a cutout featured slat. 
         FIG. 11  is a top view a cutout panel assembly with a plurality of interwoven  FIG. 10  slats. 
         FIG. 12  is a pictorial view of a standard formed slat. 
         FIG. 13  is a pictorial view of a ribbed and channeled formed slat. 
         FIG. 14  is a pictorial view of a multi-bend formed slat. 
         FIG. 15  is a pictorial view of a ducted formed slat. 
         FIG. 16  is a pictorial view of a twist-bend formed slat. 
         FIG. 17  is a pictorial view of a chamfered or angle-cut machined slat. 
         FIG. 18  is a pictorial view of an outer cutout machined slat. 
         FIG. 19  is a pictorial view of a curved machined slat. 
         FIG. 20  is a pictorial view of an inner cutout machined slat. 
         FIG. 21  is a pictorial view of a microsurface machined slat. 
         FIG. 22  is a pictorial view of auxiliary hinge feature pivotably connecting two standard panel assemblies. 
         FIG. 23  is a pictorial view of an auxiliary deflector handle feature fastened to a standard slat. 
         FIG. 24  is a pictorial view of a slideable panel assembly. 
         FIG. 25  is a section view of  FIG. 1  panel assembly in mounting configuration  1 . 
         FIG. 26  is a section view of  FIG. 1  panel assembly in mounting configuration  2 . 
         FIG. 27  is a section view of  FIG. 1  panel assembly in mounting configuration  3 . 
         FIG. 28  is a section view of  FIG. 1  panel assembly in mounting configuration  4 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to  FIG. 1 , a woven panel assembly  6  for the underbody of a tractor-trailer road vehicle is shown. The panel  6  as shown in  FIG. 1  is mounted to the lower sides of the trailer  2  between the trailer rear axles  8  and landing gear  14 . The panel  6  may alternatively extend forward beyond the landing gear  14  to the tractor wheels  12 . 
     The panel assembly  6  comprises a plurality of vertical slats  22  and interwoven horizontal slats  24 . Three mounting slats  10  are interwoven into panel assembly  6  similar to vertical slats  22 . Mounting slats  10  may be reinforced, along with the top slat and the bottom slat, to provide more rigidity to the panel. Reinforcing slats may be formed, for example, from metal, while the remaining slats may be formed from plastic. 
       FIG. 2  is a pictorial view of the panel  6  from beneath the trailer  2  as shown in  FIG. 1  and more clearly depicts the mounting slats  10  secured to the angled mounting brackets  20  and trailer frame beams  16 . Referring now to the woven end of mounting slats  10 , this end of the slat  10  is secured to angled mounting brackets  20  with fasteners  18 . Mounting brackets  20  in turn are secured to frame beams  16  with fasteners  18 , as shown. The non-woven ends of mounting slats  10  are secured to frame beams  16  with fasteners  18 . For this embodiment, mounting slats  10  are preferably bent inward and secured to the frame beams  16  a distance from brackets  20  to provide a balance of rigidity and flexibility to the panel assembly  6 . Although conventional fasteners  18  are shown in this embodiment to secure mounting slats  10  to frame beams  16 , various mounting mechanisms or auxiliary brackets are known in the art and may be suitable alternatives for securing the mounting slats to frame beams. 
       FIG. 3  is a front view of the panel assembly shown in  FIG. 1 , and illustrates more clearly the panel assembly  6  with vertical slats  22  and interwoven horizontal slats  24 . Openings  25  are inherent to the panel assembly  6  since vertical slats  22  do not directly contact other vertical slats and horizontal slats  24  do not directly contact other horizontal slats  24 . If slats are instead woven tightly such that slats  22  and slats  24  are in direct side-to-side contact with each other, it is possible that no openings  25  will be formed, or that any spacing between slats will be negligible. 
       FIG. 4  is a pictorial view of the exterior of another panel assembly  26  in a partially woven configuration shown mounted to a road vehicle underbody  38 . The lower side of the road vehicle body  28  may contact the shaped panel  26  as shown in the figure, or the vehicle body  28  may serve as a mounting location for the panel  26  using sheet metal screws. The exhaust assembly  30 , rear axle assembly  32 , and rear tire  34  are shown to the right and behind the panel  26 . The chassis opening  36  receives both the overlapping slats  40 A and  40 D. Slats  40 A,  40 D, and  40 G may have substantial bending and curvature, and also may function as mounting slats. 
       FIG. 5  is a pictorial view of the interior side of the shaped panel assembly  26  shown in  FIG. 4  which more clearly illustrates the slats  40  and holes for mounting the assembly  26  to the vehicle underbody  38 . Each slat  40  is fastened to other overlapping slats  40  with fasteners  18 . Each slat  40 B,  40 C,  40 E,  40 F is secured to mounting slat  40 G and to either mounting slat  40 A or  40 D with fasteners  18 . Slats  40 B,  40 C,  40 E, and  40 F may be tapered, angled, bent, twisted, curved or more generally machined or formed as required to obtain the desired shape, aerodynamic characteristics, and structural properties of the device. The shaped panel assembly  26  with slats  40  has openings  25  between tightly woven slats and gap regions  44  between non-woven, loosely woven, or spaced slats. Slats  40 A and  40 D may also function as a single reinforcing slat because they are fastened together with fasteners  18  and have an effective thickness greater than other slats. Slats  40 A and  40 D have holes  46  for securing with auxiliary devices after receipt by chassis opening  36 , as shown in  FIG. 4 . A flat mounting bracket  48  is secured to mounting slat  40   g  with fastener  18  as shown in the lower left of  FIG. 5 . Mounting slat  40 G may also have formed bends  42  and extended length to mount to the vehicle underbody  38  with fastener  18  as shown in the upper right of  FIG. 5 . 
     In a variation of the  FIG. 5  embodiment, slats  40 B,  40 C,  40 E, and  40 F may be removed, and the width of the remaining slats increased and/or the spacing between the slats reduced so that slats  40 A,  40 B, and  40 G constitute all the slats of the panel assembly. Preferably one or more of these remaining slats, such as slat  40 G, extends beyond the panel assembly and may be used for mounting the panel assembly by inserting an end of the extended slat through an opening in the vehicle, then using a clip or other member to secure the extended slat and thus the panel assembly in place. Extended straps may thus be mounted to the vehicle as disclosed in  FIG. 28  discussed below. 
     In some applications, only one or two of the slats may be interwoven with other slats, and in other embodiments none of the slats are interwoven. The panel assembly may thus comprise of two or more generally parallel and adjoining first slats, and two or more generally parallel and adjoining second slats each perpendicular to the first slats. 
     As noted subsequently, not all slats need be interwoven, e.g., only one or two of the slats may be interwoven with other slats. Also, the exterior surface of each slat may be a micromachined or microformed surface, as disclosed in the prior art, to further reduce aerodynamic drag when air flows over the panel assembly. The entire panel may be aerodynamically configured to reduce aerodynamic drag. 
       FIG. 6  is a pictorial view of a standard slat. The shallow hills  50  and valleys  52  of the slat, as well as the woven bend  54  of the slat, are inherent to in woven configuration. The slat as shown in  FIG. 6  is not formed bent before it is woven, rather its bend is inherent when interwoven with other slats. The hills and valleys may be formed from bends, each perpendicular to the longitudinal length of the slat, or the bend may be canted, as shown in  FIGS. 4 and 5 . 
       FIG. 7  is a side view of the standard slat shown in  FIG. 6  which illustrates the thickness dimensions of the  FIG. 6  slat. T 1  corresponds to the material thickness dimension of the  FIG. 6  slat. T 2  corresponds to the woven thickness of the  FIG. 6  slat. The woven slat thickness is measured by the overall height of a single woven slat. The thickness of a slat T 1  is typically in the range of 1/64 inch to ½ inch. T 2  is typically 1.1 to 5 times the dimension of T 1  for standard slats. 
       FIG. 8  is a top view of the standard slat shown in  FIG. 6  with length L and width W dimensions defined. L corresponds to the overall length dimension of the slat as measured along the centroidal axis of the slat. W corresponds to the width dimension of the slat as measured across the greatest dimension of the hills  50  and valleys  52  of slats. Each slat preferably has a width which is at least twice the thickness of the slat, and in most cases the slats will have a width of at least ¼ inch. 
       FIG. 9  is a pictorial view of a standard panel assembly  56  which more clearly depicts the shallow hills  50  and valleys  52  of interwoven  FIG. 6  slats. The hills  50  and selected valleys  52  are shown for the interwoven slats A-I. 
       FIG. 10  is a top view of a cutout slat which shows edge cutouts  58  in proximity to alternate bend regions  54 . 
       FIG. 11  is a top view of a cutout featured panel assembly  60  with four vertical  FIG. 10  slats interwoven with four horizontal  FIG. 10  slats.  FIG. 11  more clearly illustrates how slats may create new features and benefits in a woven assembly. In this embodiment, new assembly features created are cutout openings  62 , non-overlap regions  64 , and edge openings  66 . The advantages of the cutout openings  62  may include reduced stress concentrations of slats near the openings. Further benefits of openings  62  may include improved flexibility to the assembly and ventilation or through-flow of fluid between top and bottom regions of panel assembly  60 . 
       FIG. 12  is a pictorial view showing a standard formed slat with preformed bends  68 . In this embodiment, the similar hills  50  and valleys  52  of the  FIG. 6  slat are obtained before the slat is woven into an assembly through conventional preassembly bending or forming methods which may include line bending, vacuum forming, drape forming, or other thermoforming and forging construction methods. Alternatively, the slats may be at least partially interwoven then heated to form the respective hills and valleys. 
       FIG. 13  is a pictorial view of a ribbed and channeled formed slat with formed ribs  70  and formed channel  72 . Ribs  70  and channels  72  may be formed into slats using conventional forming means and generally in any number, shape, and direction required to achieve desired structural or aerodynamic benefits, such as improved slat rigidity and therefore panel assembly rigidity, and also for example aerodynamic drag reduction since channels or ribs may direct or deflect fluid flow for reduced drag. 
       FIG. 14  is a pictorial view of a multi-bend formed slat with formed bends  68  creating an outermost face  74 . The bends  68  and outermost face  74  may effectively form an integrated hinge or pivot whereby unconstrained bending axis or axes parallel to the bends  68  may permit either end of the slat and therefore the assembly to fold about the bending axis. Additional benefits of the bends  68  and outermost face  74  may include protection or impact absorption similar to an underbody skid plate or vehicle bumper since the face  74  of the slat may extend closer to the ground or to the front of the vehicle than other parts of the assembly, and therefore is more likely to contact the ground or foreign objects before or instead of the other assembly parts. The multi-bend formed slat may also have aerodynamic advantages if the fluid flow is properly directed or deflected by the bent slat for drag reduction or improved cooling. 
       FIG. 15  is a pictorial view of a ducted formed slat with formed bends  68  and molded ducts  76 . Ducts  76  as shown create an aerodynamic fluid flow passage which may permit through-flow or ventilation between the top and bottom regions of a slat or panel assembly. Through-flow or ventilation aerodynamic advantages achieved through ducts may differ from advantages through cutout openings  62  in  FIG. 11 , since the general flow direction and momentum, which is assumed to be substantially parallel to the width dimension W in this case, is preserved rather than disturbed. The ducts  76  direct air flow through or past the panel assembly. Additional aerodynamic advantages of ducts  76  may include increased flow attachment or flow separation as desired. 
       FIG. 16  is a pictorial view of a twist-bend formed slat with twist edges  78  and twist opening  80 . Twist edges  78  are similar to the longitudinal edges of a standard slat but their incremental angle at any location along the edge changes with respect to other edges. Twist openings  80  may be formed inherently with any twist-bend and may provide the aerodynamic advantages similar to vortex generators, deflectors, ducts, vents, or similar aerodynamic devices known in the art. 
       FIG. 17  is a pictorial view of a tapered machined slat showing tapered edges  82  on the slat at angle θ relative to the original lengthwise edge of the slat. The  FIG. 17  slat may also be referred to as a chamfered or angle cut slat. The slat may be machined to have any number of tapered edges  82  at an angle θ relative to any edge of the slat. Tapered slats are used preferably for some slats in the shaped panel assembly  26  to obtain the desired shape. Chamfers and other angle cuts to slats may be preferable for example for inserting slats into chassis openings  36 , or to obtain a flush or less abrupt edge as desired, similar to the slats. 
       FIG. 18  is a pictorial view of an outer cutout machined slat shown in  FIG. 10  and discussed above. 
       FIG. 19  is a pictorial view of a curved machined slat having curved edges  88 . Curved machined slats may be preferable in shaped panel assembly  26  whereby the slats  40  may not require expensive forming operations if they can be machined to obtain the same effective curvature of the panel assembly  26 . Further, the curved slats may direct flow in an aerodynamically advantageous manner such as slat  40 D in front of the rear tire  34 , as shown in  FIG. 4 . 
       FIG. 20  is a pictorial view of an inner cutout machined slat having inner cutouts  90  in cutout arrangement  92 . Inner cutouts  90  are shown with an elliptical shape but may be rectangular, circular, triangular, or of any other shape or pattern that can be cut into the slat. The inner cutout machined slat of  FIG. 20  may have any number of cutouts  90 . The slat as shown has nine inner cutouts  90  spaced approximately equally from each other to define the linear pattern cutout arrangement  92 . Cutouts may be arranged similar to arrangement  92 , or non-linearly. The benefits of inner cutouts  90  are similar to the benefits described for edge cutouts  58  in  FIGS. 10 and 11  whereby ventilation or through-flow of fluids between the top and bottom regions of the slat or panel assembly is obtained. 
       FIG. 21  is a pictorial view of a slat with microsurface arrangement  96 . The arrangement  96  is composed of one or more machined microsurfaces  94  which divert a fluid in relative motion to the slat surface (in this case, a leftward motion of the slat through air). Surfaces  94  are preferably formed or machined into the surface but may also be of another material or object affixed to the surface. The  FIG. 21  slat may be provided with surfaces  94  for aerodynamic benefit beyond directionality. A highly dimensional or turbulent flow may be affected by slat  21  with surfaces  94  arranged for drag reduction, improved flow control, improved flow attachment, improved flow separation, turbulence generation or reduction, or other aerodynamic benefits using microsurfaces and microsurface patterns known in the art. 
       FIG. 22  is a pictorial view of auxiliary hinge  98  pivotably connecting two standard panel assemblies  56  about hinge axis  100 . The hinge  98  is secured to panel assemblies  56  with fasteners  18 . One or both of the panel assemblies  56  may be pivoted about the axis  100  in order to quickly obtain access to regions of the underbody of a vehicle, or also for improved storage and maneuverability. 
       FIG. 23  is a pictorial view of an auxiliary deflector handle  102  fastened to a standard slat with fasteners  18 . The deflector handle  102  is not a slat but rather an auxiliary feature which can be attached with fasteners  18  to any slat in order to provide an aerodynamic deflector or other aerodynamic feature where the feature cannot be integrated into the slat. Further, the deflector handle  102  may have additional or other advantages such as to provide a handle for improved ease of transporting, mounting, or removing a panel assembly. 
       FIG. 24  is a pictorial view of a slideable panel assembly  104  with formed  FIG. 14  slats having outermost faces  74 , with the  FIG. 14  slats receiving slideable slat  106  in slide direction  108 . Slideable slats  106  may connect two panel assemblies in a sliding configuration for improved accessibility to regions of the vehicle underbody, since panel assemblies can translate in at least one slide direction  108 . Further advantages of slideable slats may include reduced size for storage and transport as well as the slideable slat functioning as a reinforcing slat to strengthen the assembly  104 . 
       FIG. 25  is a section view of the  FIG. 1  panel assembly  6 A in one mounting configuration  1 . In this mounting configuration, mounting slat  10 A is not interwoven with horizontal slats  24  but instead is secured on one end to trailer frame beam  16  with fasteners  18  and secured on the opposite end to horizontal slat  24 B with fasteners  18 . Horizontal slat  24 B as shown in  FIG. 25  is thicker and wider than other  24  slats and therefore is also a reinforcing slat. Vertical slat  22  fastened to slat  24 B with fasteners  18 , and from there above is interwoven with horizontal slats  24 . Horizontal slat  24 A, the top slat, is thicker than other  24  slats and therefore is also a reinforcing slat. Slats  24 A and  22  are fastened to mounting bracket  20  with fasteners  18 . Mounting bracket  20  is secured to frame beam  16  with fasteners  18  to substantially support panel assembly  6 A. 
       FIG. 26  is a section view of the  FIG. 1  panel assembly  6 B in a second mounting configuration. This mounting configuration is similar to the  FIG. 25  mounting configuration except that mounting slat  10 B also performs the function of a vertical slat  22 . There are major advantages of integrating mounting slats and woven slats as shown in  FIG. 26  in that the total parts, materials, and therefore cost of the device  6 B is reduced. Further differences between the  FIG. 26  configuration and the  FIG. 25  configuration include slat  24 D having a width greater than horizontal slats  24  and therefore slat  24 D also serving as a reinforcing slat. Still further differences between the  FIG. 26  configuration and the  FIG. 25  configuration include horizontal slat  24 C also functioning as a mounting slat with fasteners  18  securing the  24 C slat to frame beam  16 . Slat  24 C is thicker, bent similar to mounting bracket  20 , and is therefore a featured, reinforcing, and mounting slat. 
       FIG. 27  is a section view of the  FIG. 1  panel assembly  6 C in a third mounting configuration. The mounting configuration of  FIG. 27  is similar to  FIG. 26  mounting configuration except that mounting slat  10 C is secured to frame beam  16  at both ends of the slat passing through a hole or aperture then secured a with fastener  18 . A further difference between the  FIG. 27  configuration and the  FIG. 26  configuration is that the device  6 C includes horizontal slat  24 E, the top slat, which is thinner in width but formed of a stronger material than horizontal slats  24  and is therefore also a reinforcing slat. With mounting slat  10 C now functioning as a mounting slat at both ends of the slat, cost reduction and ease of installation advantages may also be realized with fully integrated mounting slats. 
       FIG. 28  is a section view of the  FIG. 1  panel assembly  6 D in a fourth mounting configuration. This mounting configuration is similar to the  FIG. 26  mounting configuration except that mounting slat  10 D with holes not utilized by fasteners is received by slot or hole  36  in the chassis, shown as part of frame beam  16 , and secured from by a pin or clip style lock  110  which prevents the mounting slat from releasing slat  10 D while providing advantages such as improved mounting and removability of the assembly  6 D. 
     As disclosed herein, a first plurality of slats are interwoven with the second plurality of slats to achieve the desired configuration of the panel. Each slat in the first and second set of slats may be interwoven between the other set of slats, such that both the front and rear faces of the interwoven slat engage front and rear faces of the other slats. In other applications, only the slats from one set may be interwoven with a parallel set of slats which are not interwoven. Also, it is preferable for an interwoven first slat to rest on the front face of one of the second slats, then on the back face of the adjacent second slat, and then on the front face of the next adjacent second slat, etc. In other applications, one slat may span more than one intersecting slat. For example, a horizontal slat could pass over two vertical slats, then under two vertical slats, then over two vertical slats, etc. Also, a plurality of slats in a set of slats may be interwoven with another set of slats, but all slats in that set may not be interwoven. 
     Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope.