Abstract:
An apparatus for reducing atmospheric drag on a vehicle. The apparatus includes an airfoil having a receiving feature, wherein the airfoil is attachable with a back portion of the vehicle. The apparatus includes at least one extender attachable with the back portion of the vehicle, and a slide arm attached to the at least one extender and mateable with the recess portion of the airfoil. The apparatus is configured such that when the slide arm is disposed in the receiving portion of the airfoil, the airfoil is in an extended position relative to the back of the vehicle. The apparatus is further configured such that applying a force on the airfoil in a direction substantially perpendicular to the back portion of the vehicle buckles the airfoil, thereby lifting the slide arm from the recess and moving the airfoil to a retracted position.

Description:
[0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 12/969,456, filed on Dec. 15, 2010, and titled “Apparatus for Reducing Drag on a Vehicle” (the &#39;456 application), which claims priority to U.S. Provisional Patent Application No. 61/374,418, filed Aug. 17, 2010, titled “Apparatus for Reducing Drag on a Vehicle,” and the &#39;456 application is a continuation-in-part of U.S. patent application Ser. No. 11/653,536, filed Jan. 16, 2007, titled “Apparatus for Reducing Drag on Vehicles,” now U.S. Pat. No. 7,862,102. The disclosures of the above-recited prior applications are each hereby incorporated herein by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    Aspects of this invention relate generally to the field of atmospheric drag reduction, and more particularly to an apparatus for reducing drag on vehicles. 
         [0004]    2. Background of the Invention 
         [0005]    When a vehicle is in motion, a low pressure area generally forms at the rear of the vehicle, and the low pressure area may result in increased drag. The increased drag can increase resistance to the motion of the vehicle and force the engine of the vehicle to work harder, and as a result reduce mileage, among other things. The increased drag is often aggravated by the shape of the vehicle. For example, the square-shaped rear end of a semi-tractor trailer may cause far more drag than the round-shaped end of a sports car. 
         [0006]    There have been a number of drag reducing devices described in the related art. For example, U.S. Pat. No. 5,280,990 to Rinard (“Vehicle Drag Reduction System,” issued on Jan. 25, 1994) describes fixed-position mounted vanes to direct air to the rear of a semi-tractor trailer. Similar devices are found in U.S. Pat. No. 3,999,797 to Kirsch et al. (“Airvane Device for Bluff Vehicles and the Like,” issued on Dec. 28, 1976) and U.S. Pat. No. 3,960,402 to Keck (“Vehicle Flow Direction Vanes,” issued on Jun. 1, 1976). 
         [0007]    U.S. Patent Application Publication No. US2004/0256885 to Bui (“Rear Spoiler With Motorized Vertical and Angle Adjustability, published on Dec. 23, 2004), which provides an adjustable rear spoiler that comprises a wing-like mechanism for trucks, has an electric motor actuator for transmitting rotational motion to a worm gear box assembly, along with a wing unit and wing mounting brackets attached to upper linkage supports to create pivotal angle adjustments. 
         [0008]    U.S. Pat. No. 6,045,095 to Parrish, IV (”Vane-Airfoil Combination,” issued on Apr. 4, 2000) shows a vane-airfoil combination that comprises a rotating set of vanes located in front of the leading edge of the airfoil assembly. WIPO Application No. W092/19485 to Eliahou (“Vehicle Streamlining Device for Pressure Drag Reduction,” published on Nov. 12, 1992) discloses a device for diverting air at the rear of a trailer that comprises a flap for streamlining a vehicle to reduce drag. The flap is raised or lowered by an actuator connected to the vehicle speedometer. U.S. Pat. No. 1,714,609 to Massey (“Airplane,” issued on May 25, 1928) shows a dual airfoil for vehicles that comprises a pair of airfoils that provide lift and have forward and rear positions. U.S. Pat. No. 1,913,169 to Martin (“Wing and Like Member for Aircraft,” issued on Jun. 6, 1933) provides a combination triple airfoil for vehicles that provide lift and reduce drag and have staggered positions relative to one another. 
         [0009]    U.S. Pat. No. 4,810,022 to Takagi et al. (“Automotive Vehicle With Adjustable Aerodynamic Accessory and Control Therefor,” issued on Mar. 7, 1989) discloses an adjustable aerodynamic spoiler with a controller that has spoiler settings regulated automatically by sensed driving conditions, such as vehicle speed, crosswinds and the like. 
       SUMMARY 
       [0010]    There remains an unmet need to more effectively reduce the drag caused by the low pressure area that is created behind a moving vehicle. Aspects of the present invention provide an apparatus for reducing drag on vehicles via features that may be mechanically actuated. Another variation in accordance with aspects of the current invention includes a foil disposed in a retracted position that may be deployed into an expanded position. According to various example aspects, the foil may be activated via a series of arms and pivots, and the foil may deploy in several segments from a retracted position to a fully expanded position. 
         [0011]    Other aspects and advantages will become apparent in the following description and the features of novelty which illustrate exemplary aspects of this invention will be pointed out with particularity. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Various example aspects of the systems and methods in accordance with aspects of this invention will be described in detail, with reference to the following figures, wherein: 
           [0013]      FIG. 1A  is a perspective view of an apparatus for drag reduction in an expanded position, according to various aspects of the present invention; 
           [0014]      FIG. 1B  is a top view of the apparatus of  FIG. 1A  in an expanded position; 
           [0015]      FIG. 2A  is perspective views of the apparatus of  FIG. 1A  in a retracted position; 
           [0016]      FIG. 2B  is a partial perspective view of the apparatus of  FIG. 1A  in a retracted position, with partial omission; 
           [0017]      FIG. 3  is perspective view of the apparatus of  FIG. 1A  in a partially expanded position, with partial omission; 
           [0018]      FIG. 4  is a perspective view the apparatus of  FIG. 3  in a further expanded position, with partial omission; 
           [0019]      FIG. 5  is a perspective view of the apparatus of  FIG. 4  in fully expanded position, with partial omission; 
           [0020]      FIG. 6  is a top view of an apparatus for drag reduction in accordance with another aspect of the present invention, in an expanded position; 
           [0021]      FIG. 7A  is a top view of portion A of the apparatus of  FIG. 6  in a retraced position; 
           [0022]      FIG. 7B  is a top view of portion B of the apparatus of  FIG. 6  in an expanded position; 
           [0023]      FIG. 7C  is a top view of portion C of the apparatus of  FIG. 6  in an expanded position; and 
           [0024]      FIG. 7D  is a top view of o portion D of the apparatus of  FIG. 6  in an expanded position. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Various features and advantages in accordance with aspects of this invention are described in, or will be apparent from, the following detailed description of various example implementations. 
         [0026]      FIGS. 1A-2B  are perspective and top views, respectively, of an apparatus for drag reduction  100 , according to various aspects of the present invention, shown in an expanded position and a retracted positions. In  FIGS. 1A and 1B , a sectioned thin profile wind diverting material  110  (each wind diverting material also interchangeably referred to herein as a “airfoil”) is shown as fully expanded. The foil may comprise a single sheet of material or may be formed by a series of segments that are deployed as a result of the expansion of the foil  110 . A more detailed description of an example structure of the segmented foil  110  is given in applicant&#39;s co-pending U.S. patent application Ser. No. 12/969,456, which is incorporated by reference herein. In the expanded position, the advantageous drag reducing position is a position somewhat angled or curved in an inward curve relative to the surface of the back portion  125  of the vehicle  120 , so as to follow generally the fluid flow of air past the rear of the vehicle  120 . However, according to various aspects of the current invention, other advantageous drag reducing positions may be determined. 
         [0027]      FIG. 2A  shows a perspective view of the apparatus for drag reduction  100 , where the airfoil  110  is held in a retracted position.  FIG. 2B  shows a partial perspective view the apparatus for drag reduction  100 , in a retracted position, with the airfoil  110  omitted. According to various aspects, the airfoil  110  may held in the retracted position under the pressure of one or more biasing features, such as springs, or torsion pins that bias arms towards a retracted position. A portion  105  of the sectioned airfoil  110  may be pivotally fixed to a portion of a vehicle  120 , such as the rear portion  125 , in order to fix the airfoil  110  to the vehicle  120 . It should be noted that the sectioned airfoil  110  may be held in the retracted position via a tension built into the device or with a latching feature, for example, as described below in more detail. 
         [0028]    In addition to the airfoil  110 , the drag reduction device  100  includes a series of arms, pivots, and stops, which allow the airfoil  110  to fully open and remain locked in an opened position until a closing force is provided. The drag reduction device includes a plurality of extenders  200 . Each of the extenders  200  includes a plurality of elements that allow the airfoil to pivot away from the surface of the back portion  125  of the vehicle  120 . The extending and locking devices also allow the airfoil to extend in a curved direction, forming an arcuately cross-sectional shaped portion  118 . Each of the extenders  200  may include a first pivot  202 , a second pivot  204 , a third pivot  206 , a first arm  208 , a second arm  210 , a slide ramp arm  212 , and a support arm  214 . The airfoil  110  may include a fourth pivot  205 . When multiple extenders  200  are present, a stabilizing arm  216  may be used to connect each of the second arms  210  together so that the second arms  210  move together. The drag reduction device  100  may further include a slide arm  112  and a stop  114 . A first end of the first arm  208  may be pivotally connected to a surface of the back portion  125  of the vehicle  120  via a bracket  220 . The pivot provides rotation about an axis relative to the vehicle  120 . A second end of the first arm  208  may be connected to the slide arm  112 . As each of the first arms  208  may be connected to the slide arm  112 , the slide arm  112  may comprise a single elongated arm extending along the height of the airfoil  110 . The slide arm  112  may not be secured at any other point along its length, aside from being connected to the first arms  208 , and therefore, the slide arm  112  may not restrict movement of the first arm  208 . In accordance with another aspect of the present invention, the slide arm  112  may be slideably attached to airfoil  110  and/or slide ramp arm  212  and/or stop  114  as part of the slide motion and to support first arms  208 . Because the first arms  208  are secured to the back portion  125  of the vehicle  120  in a pivoting manner at first ends, while the second ends are connected to a freely moveable slide arm  112 , the first arms  208  are free to pivot about pivot  202  when a rotational force is applied to the slide arm  112 . As shown in  FIG. 1A  and  FIGS. 3-5 , each of the first arms  208  and the second arms  210  may include two arms to coupled together via pins, so as to accommodate motion about first and second pivots  202 ,  204 . Additionally, the first arms  208  may be secured to the back portion  125  of the vehicle  120  so that the first arms  208  are biased to the non-pivoted/retracted position. 
         [0029]    A first end of each second arm  210  may be joined to a first arm  208  such that the second pivot  204  is located at the point where the arms  208 ,  210  join. A second end of each second arm  210  may be connected to a second end of the airfoil  110 , located opposite the portion of the airfoil  110  that is pivotally secured to the back portion  125  of the vehicle  120 . Each second arm  210  may be connected to the airfoil  110  via a connecting arm  218 . The connection between the first arm  208  and the second arm  210  is located at the second pivot  204 , while the connection between the airfoil  110  and the back portion  125  of the vehicle  120  is located at the third pivot  206 . The airfoil may include a fourth pivot  205  located at a point where the airfoil  110  meets the arms  210 . This arrangement allows each second arm  210  to pivot about the pivot  204 , and the airfoil  110  to pivot about the pivots  205 ,  206  when a force is applied to the airfoil in a direction about a vertical axis relative to the vehicle  120 . The second and third pivots  204 ,  206  are configured to allow rotation about a vertical axis, but not about a horizontal axis, relative to the vehicle  120 . 
         [0030]    The support arm  214  may be connected at one end to the first arm  208 , while a second end of the support arm  214  may be connected to the slide arm  112 . The support arm  214 , when connected in this way, provides stability between the first arm  208  and the slide arm  112  and may provide an addition gripping point for an operator. The slide arm  112  may be freely supported by the first arm  208  and the support  214 , such that the slide arm  112  can slide in a direction substantially perpendicular to the back portion  125  of the vehicle  120 . Because the first arm  208  is attached to the slide arm  112  and is pivotable about pivot  202 , when a force is applied to pivot the first arm  208 , the freely supported slide arm  112  correspondingly will move toward or away from the back portion  125  of the vehicle  120 . As shown in  FIG. 4 , which is discussed in more detail below, in one position the slide arm  112  abuts of the ramp arm  212  and is free to slide along the ramp arm  212  when the first arms  208  are pivoted. The ramp arm  212  increases in thickness along its length, thereby providing a ramp shape. The stop  114  may protrude substantially perpendicular from the planer surface direction of the airfoil  110  and be spaced at distance away from the ramp arm  212 . The distance between the stop  114  and the ramp arm  212  may be about equal to the thickness of the slide arm  112 , thereby forming a receiving feature  116 . As is discussed in more detail below, the slide arm  112  may be slid along the entire length of the ramp arm  212 , until the slide arm rests within the receiving feature  116  and abuts the stop  114 . 
         [0031]    A shown in  FIG. 1A , the drag reduction device  100  may include a plurality of extenders  200 . Each of the extenders  200  may include one or more first arms  208 , second arms  210 , support arms  214 , first pivot  202 s, and second pivots  206 . Each of the extenders  200  may likewise include one or more corresponding brackets  220  and corresponding ramp arms  212 . However, as shown in  FIG. 1A , in one example implementation, each of the extenders  200  may connect to a common slide arm  112 . This arrangement may provide sufficient stability to control the extension and retraction of the airfoil, while ensuring the airfoil is maintained in position. 
         [0032]    Example operation of the drag reduction device  100  will now be described, starting from the closed position shown in  FIGS. 2A and 2B . As shown in  FIG. 2A , in the closed position, the airfoil  110  may be positioned against, and extend parallel to, the length of the back portion  125  of the vehicle  120 .  FIG. 2B  shows the same position as  FIG. 2A , with the airfoil  110  omitted in order to reveal the underlying structure. As shown in  FIG. 2B , in the closed position the first arms  208  and the second arms  210  are substantially parallel to each other and parallel to the back portion  125  of the vehicle  120 . Furthermore, in this example implementation, the slide arm  112  is positioned at the pivot  206 , so as to nearly contact the back portion  125  of the vehicle  120  and abutting the thinner end of the ramp arm  212  ( FIG. 3 ). To begin extending the airfoil  110 , a force may be applied to the end of the airfoil  110  that is opposite the pivot  206 , for example. The force may be applied to allow the airfoil  110  to begin to pivot about pivot  206 . 
         [0033]      FIG. 3  shows a partially extended position where the airfoil  110  has been fully lifted away from the back portion  125  of the vehicle  120 . Because an end of the airfoil  110  is connected to an end of the second arm  210 , the movement of the airfoil  110  about pivots  206  causes second arms  210  to pivot about pivots  204 . As the airfoil  110  continues to pivot about pivot  206 , the second arms  210  continue to pivot about pivot  204  along direction A. This motion continues until the position shown in  FIG. 3 , where the second arm  210  has been pivoted about pivot  204  until the point where the second arm  210  reached a maximum pivot point along direction A. The connection between the first arms  208  and the second arms  210  may be configured so that once the second arm  210  is in the maximum pivot position relative to the first arms  208 , the second arms  210  can no longer pivot about pivot  204 . Thus, an aspect of the connection point (e.g., a stop) between the first arms  208  and the second point  210  may serve to limit how far the airfoil  110  can be extended from the back portion  125  of the vehicle  120 . As shown in  FIG. 3 , at the point where the second arm  208  is at the maximum pivot point along direction A, the slide arm  112  remains in a similar position to as shown in  FIG. 2B . Thus, during the pivoting of the airfoil  110  about pivot  206  and during the pivoting of the second arms  208  about the pivot  204 , the first arms  208  remain relatively stationary and do not pivot about pivot  202 . 
         [0034]    After the airfoil  110  has been extended to the farthest point as limited by second arms  208 , a force is then applied to the ends of the first arms  208  that are opposite from the pivot  202  ends of the first arms  208 . For example, an operator may grip the support arm  214  and pull the support  214  in a direction away from the back portion  125  of the vehicle  120 . As discussed above, in this example implementation, the support arm  214  is connected to the first arms  208  and both the support arm  214  and the first arms  208  are connected to the slide arm  112 , while the slide arm  112  is free to move. Thus, when the pulling force is applied to the support arm  214 , the first arms  208  begin to pivot about pivot  202 , moving the slide arm  112  with this motion. As the first arms  208  continue to pivot about pivot  202 , the slide arm  112  slides along the ramp arm  212 .  FIG. 4  shows the position of the drag reduction device  100  where the first arms  208  have been partially pivoted about the pivot  202 , and the slide arm  112  is positioned about half way along the length of the ramp arm  212 . As shown in  FIG. 4 , the pivoting of the first arms  208  about pivot  202  also causes the second arms  210  to follow a similar motion, which in turn causes the airfoil  110  to move along with the second arms  208 . As shown in  FIG. 4 , this arrangement and motion begins to give the airfoil  110  an arcuate cross-sectional shape  118 . 
         [0035]    As additional force is applied so as to continue to pivot the first arms  208 , the slide arm  112  will eventually travel to the thickest portion of the ramp arm  212 . Then, as shown in  FIG. 5 , once the slide arm  112  passes beyond the end of the ramp  212 , the slide arm  212  enters into the receiving feature  116 . As discussed above, the receiving feature  116  may include a space or recess formed between the stop  114  and the ramp arm  212 , for example. Once the slide arm  112  is positioned within the receiving feature  116 , the stop  114  prevents further motion of the slide arm  112 . Thus, any additional pivoting of the first arm  208  will be prevented, and likewise, the airfoil  110  cannot be further extended. Additionally, because the slide arm  112  thereby also abuts the end of the ramp arm  212 , the first arm may also be prevented from being pivoted in the reverse direction toward a retracted position. Thus, in the position shown in  FIG. 5 , the components are locked from further pivoting and the airfoil remains in a locked position, being fully extended and having an arcuate cross-sectional shape. 
         [0036]    Once locked, the operator of the vehicle is free to drive with the airfoil fully extended without risk of the airfoil closing. The locked arrangement, along with the arcuate cross-sectional shape  118  of the airfoil, prevents wind forces from inadvertently closing the airfoil, as air flow that occurs during driving will be directed so as to impart pivoting forces about pivot  202 . 
         [0037]    Unlocking the drag reduction device  100  from the locked position requires imparting force such that the slide arm  112  exits the receiving feature  116 . For example, when a force is applied to the end of the airfoil  110  that connects to the second arms  210  in a direction substantially perpendicular to the back portion  125  of the vehicle  120 , the applied force causes the airfoil  110  to buckle outwardly. The buckling of the airfoil  110  allows the slide arm  112  to lift out of the receiving feature  116 . Once the slide arm  112  has been lifted from the receiving feature, the locking forces are no longer in place, and the above-described opening steps can be performed in reverse to return the airfoil  110  to the retracted position. In one aspect of the present invention, the drag reduction device  100  is biased to return to the closed position as soon as the locking forces are removed. For example, the first arms  208  may be pretensioned so that the first arms  208  are biased to pivot about pivot point  202  towards the back portion  125  of the vehicle  120 . Furthermore, the above-described biasing features may be implemented to provide additional biasing force to ensure the drag reduction device  100  remains closed until intentionally re-opened by an operator. 
         [0038]    One advantage of the bias and locking design is that an operator of the vehicle can close the drag reduction device  100  without exiting the vehicle. The operator may back the vehicle up slowly until the end of the airfoil  110  that connects to the second arm  210  contacts a wall of a building or other stable surface. The operator may continue to back up the vehicle so as to provide a force imparted by the stable surface in a direction substantially perpendicular to the back portion of the truck. This causes the above-described buckling of the airfoil to occur, which then completely closes due to the pretension or biasing forces. 
         [0039]      FIG. 6  shows a top view of a drag reduction device  600  in accordance with another aspect of the present invention. Aspects of the drag reduction apparatus  600  that are similar to aspects of the drag reduction apparatus shown in  FIGS. 1-5  are shown similar reference numbers. Drag reduction device  600  may include an airfoil  610  having a plurality of segments  610   a,    610   b,    610   c  and a plurality of hinges  630 ,  632 . Hinge  630  connects first section  610   a  with pivoting second segment  610   b  and hinge  632  pivotally connects second segment  610   b  with third segment  610   c.  The drag reduction device  600  may include extenders  700 , which allow for movement of the airfoil  610  via pivots  702 ,  704 ,  706 , similarly as shown and discussed above with respect to  FIGS. 1-5 . The drag reduction device  610  may likewise include a ramp arm  712 , a slide arm  612 , a stop  614 , and a receiving feature  616  to provide for a locking position in a similar manner to that shown and described above. The drag reduction apparatus  600  may further include a latch  620  for securing the drag reduction apparatus  600  in a closed position. 
         [0040]      FIG. 7A to 7D  show detailed views of portions  7 A- 7 D of  FIG. 6 , respectively.  FIG. 7A  shows operation of the latch  620  when the drag reduction device  600  is in a retracted position. As shown in  FIG. 7A , when the first arm  708  and the second arm  710  are substantially parallel to the back portion  125  of the vehicle  120 , an end portion of the third segment  610   c  and an end portion of the second arm  710  may be aligned with a portion of the first arm  708  that is connected to the bracket  720 . The third segment  610   c  may include a groove  622  sized and shaped to receive an end of the latch  620 . In the retracted position the second arm  710  may contact the bracket  720 , which enables alignment of the groove  622  with the latch  620 . The latch  620  may then be pivoted about pivot  624  so that the latch  620  enters the receiving groove  622 . Once the latch  620  is disposed in the receiving groove  622 , the second arm  710  is unable to move into the expanded position until the latch  620  is pivoted out of the receiving groove  622 . While the securing feature is shown in combination with the drag reduction device  600 , aspects of the present invention may include similar securing features, and biasing features, for the drag reduction device shown in  FIGS. 1-5 . Furthermore, aspects of the present invention may include other securing features that serve the similar functions to the latch  620   
         [0041]      FIG. 7B  shows details and features of the first segment  610   a  for pivoting about pivot  706 , along the lines described above.  FIG. 7C  shows that the hinge  630  allows the second segment  610   b  to pivot about pivot  624  relative to the first segment  610   a.    FIG. 7D  shows that the hinge  632  allows the third segment  610   c  to pivot about the pivot  636  relative to the second segment  610   b.    
         [0042]    While aspects of this invention have been described in conjunction with the exemplary variations outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, thereof whether known or that are or may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example aspects of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope hereof. Therefore, aspects of the invention are intended to embrace all known or later-developed alternatives, modifications, variations, improvements, and/or substantial equivalents.