Abstract:
An elongate moldable, flexible material or sealing body positioned between adjacent walls of a pickup truck and canopy mounted to a pickup truck bed, to permit windows of the pickup cab and canopy to be open for communication between the cab space and the canopy space, as well as to keep out wind, rain, dust and debris. The sealing body encompassing the perimeter of the windows of the cab and canopy. The sealing body also having a width dimension greater than its thickness dimension. Further, the sealing body having the ability to rotate about its central axis to accommodate varying dimensions of gaps between the cab wall and the canopy wall. The sealing body also having a fast compression rate and a compression memory. The slow expansion rate or “slow memory” giving the added benefit of avoiding abrasion of the sealing body against the cab or canopy walls due to vibration of the cab or canopy structure.

Description:
RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application 60/449,218 filed on Feb. 24, 2003. 

   BACKGROUND OF THE INVENTION 
   a) Field of the Invention 
   The present invention relates generally to devices used with pickup trucks that include a canopy over the truck bed and, more particularly, to devices especially adapted for providing a seal between a truck cab window and the canopy window. 
   b) Background Art 
   Numerous devices adapted for providing a seal between a truck cab and a canopy sitting on a truck bed have been provided in the prior art. For example, U.S. Pat. No. 3,840,266 (Carlson), shows a sealing gasket of compressible material that is placed between a cab and cap. It is held in place by both its resilience and an adhesive element that bridges the space between the cab and cap, and contacts the seal material. U.S. Pat. No. 3,837,700 (Van Slyke) shows a sealing element which is between the cab and a vehicle carried camper and which is a tubular element which may be inserted in place and inflated to hold it in place. 
   The disclosure in U.S. Pat. No. 5,924,762 (Pols) provides an inflatable gasket that fits in the space between the cab and the cap. The outer surface is provided with ribs to improve adhesion to the body surfaces. U.S. Pat. No. 5,516,185 (O&#39;Donnell et al) shows a cab to cap gap filler in which a moldable material in a tubular container is forced between the walls and tend to become wedged and retained in place. There are also magnets located in the device to hold it in an operative position. 
   U.S. Pat. No. 4,616,871 (Pettit) shows a camper shell boot that is placed between the cab and cap, and is maintained in place by its resilience. U.S. Pat. No. 4,294,485 (Engelhard) shows a boot or gasket that is placed between the cab and cap, one side being fixed to the window frames and the other held in place by magnet 27. The disclosure of U.S. Pat. No. 4,114,943 (Engelhard) provides a gasket device between the cab and cover on a truck in which the edges of the gasket are secured to the window frames of each element. 
   U.S. Pat. No. 3,840,266 (Carlson) shows a sealing gasket of compressible material that is placed between a cab and cap. It is held in place by both its resilience and an adhesive element that bridges the space between the cab and cap, and contacts the seal material. 
   While these patents may be suitable for the particular problem in which they address, they would not be as suitable for the purposes of the present invention as heretofore described. 
   SUMMARY OF THE INVENTION 
   One embodiment of the invention provides a sealing body which can be quickly and easily applied to fill a gap between a pickup truck rearward window and a canopy forward window. In doing so, communication between the cab and canopy is achieved. This seal keeps out unwanted wind, dust and debris when the communicating windows of the cab and the canopy are open to each other. 
   The sealing material is made out of an elongated moldable, flexible material. The sealing material has a fast compression rate and a very slow expansion rate. This “slow memory” of expansion avoids abrasion of the cab or canopy with any type of irritant such as dust or debris that may be between the seal and the cab or canopy. Any vibration of one wall will not be transferred to the other through the seal. Consequently the seal will not provide any substantial force which might cause scratching of either the cab surface or the canopy surface. 
   In one form the sealing body has two different dimensions, where the width dimension is substantially wider than the thickness dimension. Having these different dimensions is useful when there is a change in the gap dimension between the cab wall and canopy wall. The seal can be rotated around its central axis ninety degrees to fit more adequately between the adjacent surfaces as required. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevation view of a pickup truck with a canopy attached to the truck bed, where the seal of this invention is mounted in between the truck cab and canopy; 
       FIG. 2  is an elevation of the cab rear wall, with the center window of the cab shown in the open position; 
       FIG. 3  is an elevation of the sealing body positioned to surround the open cab window, and also to encompass the open canopy window not shown; 
       FIG. 4  shows a cross sectional view taken at line  114  in  FIG. 2  of the cab rear wall, the lateral perimeter gap between the cab window and canopy, and front canopy wall; 
       FIG. 4A  shows a cross sectional view of the cab rear wall, the lateral perimeter gaps where the inner window edges are not aligned in the longitudinal direction; 
       FIG. 5  shows a cross section view taken at line  5 — 5  in  FIG. 2  showing the cab rear wall, the sealing body and the front canopy wall; 
       FIG. 5A  shows a cross section view showing the cab rear wall, the lateral perimeter gaps where the upper and lower inner window edges are not aligned in the longitudinal direction; 
       FIG. 6  shows a cross sectional view taken at line  6 — 6  in  FIG. 3  showing the cab rear wall, the elongate member and the front canopy wall; 
       FIG. 7  shows a cross sectional view taken at line  7 — 7  in  FIG. 3  showing the cab rear wall, the elongate member and the front canopy wall; 
       FIG. 8  shows a rearward view along the longitudinal axes of the elongate member being installed on to the perimeter sub-region of the front window; 
       FIG. 9  shows a graph of the compression rate of the sealing material when a pressure is applied thereto; 
       FIG. 10  shows a graph of the expansion rate or slow memory characteristics of the sealing material where the x-axis time units are in order of magnitude creature than the x-axis time units of  FIG. 9 ; 
       FIG. 11  shows a cross section of the sealing body shape; 
       FIG. 12  shows a dynamic view where the cab wall moves with respect to the canopy wall laterally for an instant where the elongate member maintains a seal; 
       FIG. 13  shows a dynamic view where the cab wall moves with respect to the canopy wall vertically for an instant where the elongate member maintains a seal and like  FIG. 12 , the abrupt motion that generally occurs is not invoke the compression memory of the elongate member. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In general, the disclosure herein relates to sealing the area between the very window on the cab of a truck, specifically a pickup truck, and the forward window of a canopy. For reference purposes as shown in  FIG. 1 , an axes system  10  is defined where the arrow indicated at  12  indicates a longitudinal direction and the arrow itself shows a forward direction. The arrow  14  shows a vertical axes. Referring to  FIG. 2 , the arrow  16  indicates a lateral axes. The axes system are shown for general reference and not intended to limit the invention but rather the description and the general direction and positioning of the components described herein. 
   There will now be a discussion of the overall operating environment followed by of form of an implementation of the present invention. As shown in  FIG. 1 , there is a conventional automotive vehicle, commonly known as a pickup truck which is indicated generally at  20 . The truck comprises a cab region  22  having an interior cab cavity and truck bed region  24  positioned rearward of the cab region  22 . A conventional canopy  26  having a canopy cavity region is mounted in the bed  24 , the canopy  26  having a front wall  28  disposed closely adjacent and substantially parallel to the rear wall  30  of the cab  22 . In  FIG. 2 , the rear cab wall  30  is shown as being provided with a cab rear window  32 . 
   The cab rear window has a first inner edge portion  39  (see  FIG. 2 ). Alternatively the first inner edge portion can be positioned on the stationary window edge indicated at  41  (see  FIG. 4 ). The inner edge portion is the inner most region of the window that can support the elongate member  78  as shown in  FIGS. 6 and 12 . The installer can choose which surface to place the elongate member depending upon the installation circumstances. The canopy has corresponding inner edge portions  39   a  and  41   a . In a like manner, the second inner edge portion  43  and  45  as shown in  FIG. 2  represent inner most regions of the window that can support the elongate member  78 . The canopy has second inner edge regions for supporting the elongate member similar to the first edge regions  39   a  and  41   a  of  FIG. 4  but on the opposite lateral side of the canopy window  34 . As shown in  FIG. 5 , the upper inner edge  47  of the cab window  32  defines the innermost portion of the upper region  42  (defined below) that can engage the elongate member  78  as shown in  FIGS. 7 and 13 . The canopy window  34  has a similar inner edge portion  47   a . Finally, located in the lower portion of the cab window  32  in  FIG. 5  there is a lower inner edge  49  and the canopy window  34  has a lower inner edge  49   a . The lower edges  49  and  49   a  are the inner most regions that can support the elongate member  78  as shown in  FIGS. 7 and 13 . 
   The cab rear window  32  and the canopy front window  34  comprise a perimeter region  36  that is at an approximate location surrounding the central open area  37 . More specifically, the cab window perimeter region  36  comprises a first and second lateral perimeter regions  38  and  40 . As shown in  FIG. 4 , the first lateral perimeter region  38  is the general area located laterally with respects to the central open the  37 . The lateral perimeter regions are adapted to engage the elongate member  78  as described further herein. 
   The perimeter regions  36  of the cab rear window  32  and the canopy front window  34  further comprise an upper perimeter region  42  and a lower perimeter region  44 . As shown in  FIG. 5 , the upper perimeter region  42  is positioned vertically above the lower perimeter region  44 . It should be noted that the perimeter regions of the cab and the canopy are substantially aligned with respects to the longitudinal axes. However, the operational aspect of the perimeter regions is to provide a surface to engage the elongate member  78 . Therefore, the definition of the perimeter regions  38 ,  40 ,  42  and  44  is defined broadly. For example, a perimeter region may be a glass portion or painted portion of either the cab window or the canopy window. It should be noted that the perimeter regions  38 ,  40 ,  42  and  44  have a corresponding longitudinal distance that can very amongst the various regions. In one form, the elongate member is adapted to address these changes in longitudinal distances for the various perimeter regions  38 ,  40 ,  42  and  44  as described further herein. 
   The perimeter regions  38 ,  40 ,  42  and  44  each further comprise a cab sub-region that is the perimeter region on the cab and a canopy sub-region that is located on the canopy. Therefore as shown in  FIG. 3 , the first lateral cab sub-region  38   a , the upper cab sub-region  42   a , the second lateral cab sub-region  40   a  and the lower cab sub-region  44   a  comprise a cab sub-region. A similar canopy sub-region is comprised of like perimeter regions but located on the canopy portion. All of the sub-regions hereabove defined on the cab are collectively referred to as the cab perimeter sub-region and likewise all of the sub-regions hereabove defined on the canopy are collectively referred to as the canopy perimeter sub-region. 
   Therefore, in general the perimeter regions  38 ,  40 ,  42  and  44  are defined as the surface areas that can support the elongate member  78 . The inner most point of the perimeter regions  38 ,  40 ,  42  and  44  is the corresponding inner edges cab and canopy windows  32  and  34  described above. 
   Now referring to  FIGS. 4 and 5 , the cab rear window  32  comprises a stationary portion  46  and a movable portion  48 . Any similar manner, the canopy front window  34  comprises a stationary portion  50  and a movable portion  52 . In most instances, sealing systems  54  and  56  are employed in the cab or window  32  and they canopy front window  34  respectively to keep moisture and the elements out on the cab and the canopy. Such a sealing system is accomplished with an interference fit between the movable portions of the windows and the stationary portions. Such an interference fit with a pliable rubber-like material is easier to accomplish when guide tracks or the like provide support for the movable window portions. As described further herein such a similar type seal can be maintained with an elongate member  78 . 
   Referring to  FIG. 5 , an upper longitudinal distance is indicated at  60 . This is an approximate distance between the rearward surface of the cab and the forward surface of the canopy located at the upper perimeter region  42 . Further, the distance indicated at  62  can function as another upper longitudinal distance. The various longitudinal distances are defined herein generally defined areas adapted to have the elongate member  78  to be mounted therein between. For example, referring to  FIG. 5A , a situation may occur where the cab or window  32  is generally positioned vertically higher than the canopy front window  34 . Alternately, the sizing of the windows may be sufficiently different where the edge portions of the transparent regions of the window are not aligned with respects to the longitudinal direction. In such a situation, the upper perimeter region  42  as shown in  FIG. 5A  has an upper longitudinal distance that is located at the area indicated at  64 . 
   Now referring back to  FIG. 5 , the lower perimeter region  44  has a lower perimeter distance  65 . In a similar manner as stated above, the lower perimeter distance may be at a lower region indicated at  66  if this is a suitable place for engaging the elongate member  78  described below. In an environment as shown in  FIG. 5A , the lower perimeter distance indicated at  68  can be the distance between the sill portions of a window and the longitudinally opposing painted surface. As shown in  FIG. 5A  the painted surface is that of the cab and the window sill surface is on the canopy; however, the arrangement can be of any variety depending upon the circumstances of environment. 
   Referring to  FIG. 4 , the first and second lateral perimeter regions  38  and  40  are now described with reference only to the first lateral perimeter region with the understanding the description is relevant to the second lateral perimeter region  40 . The first lateral perimeter region  38  comprises a first lateral longitudinal distance  70 . This distance defines a longitudinal distance that the elongate member  78  must span to provide a seal (see  FIG. 6 ). In the alternative, in some situations the first lateral longitudinal distance may be the area and distance indicated at  72  in  FIG. 4  whereby the sill or suitable surface is provided to allow the elongate member  78  to fit therein between the cab and the canopy. As shown in  FIG. 4A  the first lateral longitudinal distance can be the distance indicated at  74  or the distance indicated at  76  depending upon the particular installation environment.  FIG. 4A  shows a situation where the lateral width of the open region of the cab window is greater than the lateral width of the open region of the canopy. Of course these figures. are illustrated to show various installation environment and are not intended to limit the present invention to the particular installation environment. Rather, these illustrations are to show the versatility of the present invention to be retrofitted to a number of situations which of course far exceed the number of variations that can be shown in this disclosure. 
   It should be understood that discussion the first lateral longitudinal distances are relevant to the second lateral longitudinal distances. Normally, these distances would be the same in an installation; however, situations can occur where the first lateral longitudinal distance is not substantially the same as the second lateral longitudinal distance. This is handled in a similar manner as when the upper or lower longitudinal distances are not equal as well and such procedure for addressing the situations is described below. 
   There will now be a discussion of the method of sealing the central open area  37 . As shown in  FIG. 3 , the elongate member  78  is attached to the perimeter region  36  (note, the canopy is not shown). As shown in  FIG. 8 , the elongate member  78  comprises a first surface  80  and a second surface  82 . The first and second surface is  80  and  82  collectively are referred to as a first set of surfaces. The surfaces are substantially opposed to one another and adapted to fit in the perimeter regions between the cab and the canopy. The elongate member  78  further has a second set of surfaces that comprise a third surface  84  and a fourth surface  86 . The third and fourth surfaces are substantially opposed to one another and adapted to be interposed between the various perimeter regions of the perimeter region  36 . The elongate member also has in portions  83  and  85 . Each end portion has an end surface  87  and  89 . The end surfaces  87  and  89  are adapted to engage one another to make a complete seal around the perimeter region  36 . In one form, the elongate member is cut to the proper overall length. Alternately, several components can be employed to make comprise an elongate member. 
   The elongate member  78  has special properties whereby the material from which it is made has compressible memory features. In other words, when the fall like material that comprises the elongate member  78  is compressed for a period of time (e.g. a few minutes) the foam will tend to remain in the compressed state and expand at a very slow expansion rate. In one form, the material comprising the elongate member  78  is a vinyl nitrate blend that is closed cell and sells under the trademark DURAFOAM™. One form of constructing the elongate member is a close cell PVC/neoprene foam with compression memory. The following test Ambient temperature 65° F. where the compressed surface was 2.5×4 cm and the fully expanded foam was four centimeters and the foam sample was compressed to two centimeters for each trial run. The time for re-expansion was measured. The results are listed as Table 1 below: 
   
     
       
             
             
             
             
             
           
             
             
             
             
             
           
         
             
                 
               TABLE 1 
             
             
                 
                 
             
             
                 
               Time Compressed = 50% 
                 
               Time required to re-expand = 98% 
             
             
                 
                 
             
           
           
             
                 
             
           
        
         
             
                 
               1 
               second 
               5 
               seconds 
             
             
                 
               3 
               seconds 
               10 
               seconds 
             
             
                 
               6 
               seconds 
               12 
               seconds 
             
             
                 
               10 
               seconds 
               15 
               seconds 
             
             
                 
               30 
               seconds 
               1 
               minute 
             
             
                 
               1 
               minute 
               3.25 
               minutes 
             
             
                 
               5 
               minutes 
               45 
               minutes 
             
             
                 
               10 
               minutes 
               5 
               hours 
             
             
                 
               30 
               minutes 
               22 
               hours 
             
             
                 
                 
             
           
        
       
     
   
   Compression of the material of the elongate member can be done with a modest amount of force and as shown in the first record above the expansion of the foam member to 98% of the original width occurs relatively quickly. The initial expansion is at a higher rate than the last portion of the expansion. This initial expansion rate is defined as a quick recovery and is particularly useful for addressing vibrations and sudden movements as discussed with reference to  FIGS. 12 and 13  below. The slow expansion time indicated in the latter records of Table 1 further have a low recovery pressure that provides minimal pressure upon the contacting surface. As mentioned below, this is advantageous for reducing surface where upon the perimeter regions of the truck, particularly painted regions where grit is interposed between the elongate member  78  and the painted surface. 
   As shown in  FIG. 9 , the x-axis indicates a relatively short time increments and the y-axis indicates the thickness of a portion of the elongate member  78  that has pressure applied thereto. The compression rate of the foam with a modest amount of pressure applied to the material will compress and a relatively fast rate as indicated by the line  90 . When the material is held at a compressed position indicated on the y-axis at  92  and the pressure applied is released, the expansion rate as shown in  FIG. 10  is in order of magnitude slower than the potential compression rate. For example, the x-axis units in  FIG. 10  could be for example increments of days and, by way of contrast, the x-axis units in  FIG. 9  could be for example seconds. The y-axis units are the same for both graphs in  FIG. 9  and  FIG. 10 . The line  94  indication in expansion rate where the foam will return to its original size at a very slow rate. The compression memory is defined as the slow rate of recovery to an original size after a portion of the material is compressed for a period of time. The compression memory has a compression memory rate of expansion that is relatively slow. The period of time for compressing can be a few minutes (i.e. 5–30 minutes) or longer. The expansion rate following the compression memory can be approximately 1%–5% of the original cross sectional size expansion per hour to 3%—20% of the original cross sectional size expansion per day. 
   The expansion rate after the foam of the elongate member  78  has invoked the compression memory is slower than if the material of the elongate member  78  is compressed and shortly released which is referred to as the immediate expansion rate. This immediate expansion rate property of the elongate member  78  allows quick recovery of the elongate member  78 . The quick recovery is necessary when sudden compression forces are exerted on the elongate member  78  such as when the vehicle is traveling or a sudden load is applied to the cab  22  or the canopy  26  causing relative movement therebetween. The elongate member  78  has a support system where an outward expansion force and a vertical frictional force, the sealing body being held in a stationary position through the combination of the outward expansion force and the vertical frictional force in the perimeter region where the compression member rate of expansion provides a minimal force to transfer between the cab wall and the canopy wall. 
   The memory expansion rate is the rate of expansion after the material of the elongate member  78  has invoked the compression memory. The memory expansion rate being at a low rate of expansion (compared to the immediate expansion rate), causes a lower pressure to be imparted on the surfaces of the perimeter regions  36  of the cab and canopy windows. 
   Referring to  FIG. 11 , the elongate member is shown in a cross sectional view, where the elongate member has a sealing body width  98  that is greater than the sealing body thickness  100 . The elongate member has had elongate axis that is defined for reference purposes where the elongate axes extends lengthwise of the elongate member and is roughly positioned in between the first and second set of surfaces. As will be described further herein, the elongate member  78  is adapted to be rotated about the elongate axes to provide various widths in the longitudinal direction for sealing the perimeter region  36  as shown in  FIG. 1 . 
   In general, the cross sectional shape of the sealing body  36  is can be rectangular, oval, round, square, or any other shape that will enable the sealing body  36  to seal the perimeter region  36  adequately. Further, a rectangular cross section provides for a first and second surfaces  80  and  82  that comprise the first set of surfaces and the second set of surfaces are comprised of the third and fourth surfaces  84  and  86 . Of course other cross sectional modifications could be employed such as a hexagonal type shape providing a third set of surfaces which could have a different cross sectional distance than the first and second set of surfaces. 
   There will now be discussion of the benefits of the compression memory of the elongate member  78 . Again referring to  FIG. 9 , the sealing body  36  is comprised of a material that has a very fast compression rate as shown by curve  90  where the compression can occur in a manner of seconds, and referring to  FIG. 10 , the sealing body has a very slow expansion rate or compression memory as shown by curve  94 , where the expansion occurs over a period of hours or days. The slow memory as shown by curve  90  provides for low abrasion characteristic when dust or debris are located in-between the cab wall  30  or front canopy wall  28  at the perimeter region  36  and the surfaces  80 ,  82 ,  84  or  86  of the elongate member  78 . Because the expansion rate is low, the pressure applied to the contacted surfaces in the perimeter region  36  is low. The vibrations and other motions that occur when the vehicle is traveling cause relative motion between the canopy  26  in the cab  22  of  FIG. 1 . Although the elongate member  78  is well adapted to handle these relative motions as described further below with reference to  FIGS. 12 and 13 , the force is minimal upon the surfaces. Therefore abrasive wear upon the surfaces of the cab and canopy in the perimeter region  36  is kept to a minimum. 
   Referring to  FIG. 4 , when mounting the sealing body  36 , one method of installing the seal  36  is to open up the cab rear window  32  and the canopy front wall window  34 . The next step is to compress the elongate member  78  into the either the large or small perimeter gap regions  38 ,  40 ,  42  and  44 . Now referring to  FIGS. 6 and 7 , when a change in perimeter gap region size occurs the sealing body  36  can be rotated about its elongate axis to accommodate the change in gap size and the longitudinal direction. Now referring to  FIG. 8 , if the elongate member is not cut in more than one place than there is only a single juncture point at the end surfaces  87  and  89 . 
   The elongate member  78  is supported through a combination of the expansion force of the elongate member  78  pressing against the cab wall  30  or canopy wall  28  of the perimeter region  36  and the vertical frictional force produced therefrom. Thus, the elongate member  78  will hold itself in place after being positioned by the user. 
   By sealing the perimeter region  36  between the canopy wall  28  and the cab wall  30 , and expansion of the sealing body  36  protects against the entry of moisture and dust from the exterior. The elongate member  78  is of sufficient width  98  or thickness  100  between its first and second set of surfaces to provide adequate sealing between the canopy wall  28  and truck cab wall  30 , even when having different dimensions between the cab  22  and canopy  26  occurs around the perimeter of the window forms, or such as when one wall slopes or curves differently in relation to the other. 
   With the elongate member  36  mounted between the cab  22  and front wall  28 , the cab rear window  32  and the canopy front wall window  34  may be kept open as desired, for exchange of communication, air, or surveillance at all times without being significantly affected by rain, outside dust or other exterior weather conditions. 
   When it is desired to disengage the communication between the canopy  26  and cab  22 , it is only necessary to pull the sealing body out of its stationary position, taking advantage of the fast compression rate as shown in curve  90  of  FIG. 9 . If the elongate member is found to be too short to provide a seal around the perimeter region, an extension piece can be used that in one form can be glued together with an adhesive such as Super Glue™. It has been experience that the adhesive does not interfere with the compression, sealing or expansion of the elongate member  78 . 
   In most all pickup truck configurations, the bed portion has independent suspension than the cab portion. Therefore, when traveling or when loads are placed on either the cab or the truck bed, there is relative movement between the truck bed  24 , which supports the canopy  26 , and the cab  22 . As shown in  FIG. 12  and  FIG. 13 , there is relative movement between the canopy front wall  28  and the cab rear wall  30 . As shown in this figure, the elongate member  78  is adapted to handle this repositioning whereby the central region  110  will flex in the lateral direction to a degree to allow for the movement. Because the compression memory is not invoked until the material that makes up the elongate member is held in a certain position for a duration of time, the brief relative movements between the cab in the canopy will not invoked a more static orientation of the elongate member  78 . 
   As shown in  FIG. 13 , if they canopy front wall  28  is lifted a certain amount with respect to the cab rear wall  30 , the elongate member  78  will adjust for this brief relative motion and still provide a seal around the perimeter region  36 . Because the foam comprising the elongate member  78  has an immediate expansion rate when it is not held in place for a period of time, the elongate member  78  is particularly suited for vibrations and oscillatory movements between the cab  22  and the canopy  26  when traveling or otherwise imparting a force on either the cab or canopy  22  and  26  (e.g. loading people in the cab or heavy supplies in the truck). The elongate member can be of a closed cell foam so it does not absorb water and it can dampen noise when traveling so the occupants of the cab can be in contact with the items or pets in the bed region and not suffer from the extreme road noise when the rear window is open. 
   From the foregoing, it will be appreciated that, although embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.