Abstract:
In order to manufacture an automobile folding sunshade, continuous strips of a roll material such as thin cardboard are supplied at the same time that discrete panels of reinforcing material that is too stiff to be rolled are supplied. The strips and the discrete panels are laminated between top and bottom sheets of preferably highly reflective material such as mylar coated bubble insulation. The resulting laminate material is then cut to the correct size and shape to fit into the windshield of an automobile. The sunshade has upwardly extending tabs at the top that include the reinforced panels. The tabs engage the sun visors of an automobile. The result is an economical yet highly durable folding automobile sunshade that is easily installed in, and removed from, a windshield of a car or truck.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. provisional patent application No. 61/948,846 filed Mar. 6, 2014. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of automobile sunshades. More particularly, this invention relates to the field a durable folding automobile sunshade and a method of manufacturing the same. 
     2. Description of Related Art 
     Sunshades for placing within the windshields and other windows of automobiles and thus protecting the interiors of those autos against solar heating and sun damage have become popular, particular in geographic regions such as the American southwest where the searing desert summer sun can quickly raise the interior temperature of a parked automobile to well over 120° F., and can prematurely age, fade, and otherwise damage the interior of an automobile. Folding sunshades made of cardboard, sometimes covered with a reflecting outer surface such as mylar and plastic bubble wrap, are popular. A number of more elaborate sunshades have also been proposed and/or sold. 
     SUMMARY OF THE INVENTION 
     One shortcoming of the prior art is that a number of the inexpensive folding sunshades currently sold do not hold up well to handling and exposure to the sun. Such sunshades can droop and sag after only a season or two due to repeated handling and the effects of the sun on the materials used. Sunshades that droop and sag look sloppy. They can even droop to the extent that they fail to stay put underneath the windshield of a car, thus defeating their purpose. 
     The present invention is of an economical folding automobile sunshade that is particular resistant to droop, sagging, and other wear caused by handling and exposure to the sun, and a method of manufacturing that sunshade. The sunshade disclosed herein lasts significantly longer than comparably constructed and priced prior art folding sunshades, thus providing both cost savings for the consumer as well as a product that is significantly more eco-friendly over its life cycle. 
     According to the manufacturing method of the invention, two flexible sheets which will constitute the top and bottom covers or surfaces of the sunshade are fed into a laminating section from respective continuous rolls of material. At the same time, a number of parallel strips of rollable material that is preferably thin and lightweight are fed into the laminating section from respective continuous rolls of material. The rollable material provides some stiffness to panels of the sunshade, but is flexible enough so that the material can be provided from continuous rolls, i.e., the material is rollable, and thus can be fed into the equipment continuously. The rollable material thus constitutes a relatively weakly stiffening material, and the strips of that material constitute weakly stiffening strips. 
     At the same time, one or more discrete panels of non-rollable stiffening material are fed into the manufacturing equipment in parallel with the rollable material. The discrete panels thus constitute relatively strongly stiffening material. 
     Preferably the sheets of flexible material that will form the top and bottom panels of the sunshade include a highly reflective material such as mylar, aluminized plastic, or other such thin layers of highly reflective material. In a preferred embodiment the mylar sheets include thermal insulation. Examples of such materials are referred to variously as bubble foil insulation or thermal bubble wrap. Such materials as well as other highly light-reflective materials are well known within the automobile sunshade industry. 
     In an exemplary embodiment, the rollable stiffening material is thin cardboard that is stocked on continuous rolls, and the discrete stiffener panels are foamboard panels. Such foamboard panels provide the stiffness and strength required for what will be reinforced panels of the sunshade; however, the foamboard is too stiff to be rolled onto rolls and thus cannot be fed into the equipment continuously from rolls. 
     In an exemplary embodiment, the cardboard strips are fed into the manufacturing equipment continuously from rolls in parallel with, and at the same time as, the discrete foamboard panels, with some of the cardboard strips disposed between the foamboard panels and some of the cardboard strips disposed on the outsides of the foamboard panels. At the same time, the two mylar sheets are fed into the equipment above and below the cardboard strips and the foamboard panels. Adhesive is sprayed onto one or both of the mylar sheets and/or onto the cardboard strips and the foamboard panels, and those materials are then laminated together. 
     The material is then cut from the continuous rolls to define a laminated automobile sunshade blank, which is then die-cut or otherwise cut to the desired size and shape to fit inside the windshield of an automobile. Edging can then be stitched around the periphery of the sunshade to finish that periphery, or the peripheral edges are otherwise finished. The spaces between the cardboard strips, and the spaces between the foamboard panels and their respectively adjacent cardboard strips, define the fold lines where the sunshade will fold. 
     In the exemplary embodiment the cardboard strips are thin enough so that the edging can be stitched or otherwise affixed over the ends of those strips, with the stitching penetrating those strips. In contrast, the foamboard panels are not thin enough for the edging to be easily stitched over their ends. Accordingly, the foamboard panels extend close to, but not all the way to, the top and bottom edges of the sunshade and the stitching therefore does not penetrate those foamboard panels. The edging around the periphery of the sunshade can thus be stitched over the entire periphery, and does not have to cover the ends of the relatively thick foamboard panels. Because the foamboard panels extend close to the edges, however, the foamboard panels provide reinforcing that extends nearly the entire top-to-bottom extent of the sunshade and thus provides sufficient reinforcing to allow the sunshade to withstand the effects of sun and handling over time yet still stand upright without unacceptably dropping or sagging. 
     Alternatively, the reinforced panels may be made of a stiff material such as spring steel. The spring steel may be adhered or otherwise affixed to a carrier substrate such as the same cardboard strips that provide the weak reinforcing to the weaker panels. 
     Also in an exemplary embodiment, the sunshade has upwardly extending tabs or ears that include the foamboard stiffening panels, and that constitute reinforced tabs. The reinforced tabs are sized and positioned so that when the sunshade is placed into the windshield of an automobile and the user folds down the pivoting driver-side and passenger-side sun visors, those visors hold the tabs of the sunshade in place. Because the tabs include the foamboard stiffener panels in the reinforced sunshade panels that extend from almost top to bottom in the sunshade, the sunshade is held in place by those reinforced panels even if the rest of the sunshade would not be strong enough and robust enough to hold the entire sunshade up by themselves. The sunshade is therefore more easily installed against the interior of the windshield, and more easily removed, than various prior art sunshades. 
     The result is an economically priced yet highly durable and effective sunshade that continues to look good and function well through several seasons of even severe sun exposure and handling. 
     Exemplary embodiments of the invention will be further described below with reference to the drawings, in which like numbers refer to like parts. The drawing figures might not be to scale, and certain components may be shown in generalized or schematic form and identified by commercial designations in the interest of clarity and conciseness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is perspective drawing illustrating an overview of the automobile sunshade manufacturing process according to an illustrative embodiment of the present invention. 
         FIG. 2  is plan view of the automobile sunshade of an illustrative embodiment of the present invention but with the top cover  12  removed for clarity of illustration. 
         FIG. 3  is a plan view of the automobile sunshade of  FIG. 2  including the top cover. 
         FIG. 4  is a sectional view of the automobile sunshade of  FIG. 3  taken along section line  4 - 4 ′. 
         FIG. 5  is a closeup view of the left side of the sunshade section of  FIG. 4 . 
         FIG. 6  is a sectional view of the automobile sunshade of  FIG. 5  with the sunshade being nearly completely folded for storage. 
         FIG. 7  is a perspective view showing the sunshade of  FIG. 3  installed in the windshield of an automobile. 
         FIG. 8  is a top perspective closeup of one corner of the sunshade of  FIG. 3  but with the top cover and edging removed for clarity of illustration. 
         FIG. 9  is a top perspective view of the sunshade of  FIG. 8  showing edging being applied and stitched thereto. 
         FIG. 10  is a top perspective closeup of one corner of a sunshade of a second embodiment with the top cover and edging removed for clarity of illustration. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is perspective drawing illustrating an overview of the automobile sunshade manufacturing process according to an illustrative embodiment of the present invention. Continuous sheets of flexible roll material  10 ,  12  that will form the top and bottom surfaces or covers of finished automobile sunshade  50  are fed into the laminating section of the equipment that is exemplified by rollers  40 ,  42  for illustration purposes. At the same time, continuous strips  22  of stiffening material such as non-corrugated cardboard or other fiber material capable of being rolled from continuous rolls  24  of such material are fed into the laminating section, and stiffener panels  30  of even stiffer reinforcing material such as foamboard panels are fed into the equipment in parallel with cardboard strips  22 . There are spaces between adjacent cardboard strips  22 , and between foamboard panels  30  and adjacent cardboard strips  22 . Those spaces define where the fold lines of the finished sunshade  50  will be. 
     The reinforcing material is preferably at least three times, and can be at least five times, as stiff as the roll material. 
     The materials may be laminated together by spraying adhesive on at least either top panel  12  or bottom panel  10 , or both, and possibly on the cardboard strips  22  and foamboard panels  30 , then pressing those materials together such as by rollers  40 ,  42 . Alternative methods of lamination are possible and well known. 
     In the illustrative embodiment, the laminated material is then cut by cutters  44  into individual laminated sunshade blanks  32 . Those blanks can alternatively be, or can further be, cut by die  70  to the necessary size and shape to fit within the windshield area of various different makes and models of cars and trucks. 
       FIG. 2  is plan view of the automobile sunshade  50  according to an illustrative embodiment of the present invention but with the top cover  12  removed for clarity of illustration. Foamboard stiffener panels  30  extend generally in parallel with cardboard stiffener strips  22 . 
       FIG. 3  is a plan view of the finished automobile sunshade  50  of  FIG. 2  including the top cover  12 . The completed automobile sunshade  50  includes panels  52  that are only weakly reinforced by cardboard strips  22 , panels  54  that are strongly reinforced by foamboard panels  30 , and edging  56  which finishes the edges of the sunshade around the periphery of the sunshade. The periphery of the sunshade includes top and bottom edges  62 ,  64  and the side edges of the sunshade. Panels  54  having foamboard panels  30  define reinforced panels or stronger panels, and panels  52  define weaker panels. In other words, first and second panels  54  are stiffer than panels  52 , with panels  52  having a first stiffness and panels  54  having a second stiffness, the second stiffness being greater than the first stiffness. Preferably the reinforced panels  54  have at least one weaker panel  52  between them and at least one weaker panel  52  on either side of them. In the exemplary embodiment, each reinforced panel  54  has four weaker panels  52  between them, and each reinforce panel  54  has two weaker panels  52  disposed on their outsides, i.e., closer to the doors of the automobile. Edging  56  extends around and over the peripheral edges of the sunshade including bottom edge  62  and top edge  64 . 
     The sunshade includes upwardly extending or projecting tabs or ears  58  which include reinforced panels  54 . Foamboard panels  30  within reinforced panels  54  and ears  58  extend close to, but not all the way to, the top and bottom edges of sunshade  50 . In an exemplary embodiment, foamboard panels  30  extend to less than three inches, preferably to within 1 to 1½ inches, but not all the way to, the top and bottom edges of sunshade  50 . Foamboard stiffening panels  30  extend upwardly beyond the uppermost extent of at least some of the cardboard stiffening strips  22 . The reinforced panels  54  containing the stiffening panels  30  are positioned within the sunshade  50  and are sized to engage respective driver side and passenger side pivoting sun visors in the automobile in which the sunshade is intended to be used. 
     In one aspect, therefore, the embodiment of the folding sunshade  50  shown in  FIGS. 3 and 7  and described herein includes: (a) a first panel  54  that extends upwardly to engage the passenger side sun visor when that sun visor is in its downward or deployed position; (b) a second panel  54  that extends upwardly to engage the driver side sun visor when that sun visor is in its downward or deployed position; (c) at least a third panel  52  laterally outward of the first panel; (d) at least a fourth panel  52  laterally outward of the second panel; and (e) at least a fifth panel between the first and second panels. The first and second panels are stiffer than the third, fourth, and fifth panels; are longer than the third, fourth, and fifth panels, and are stiff enough to hold up sunshade  50  when the sunshade is deployed underneath the windshield of an automobile. The weaker third, fourth, and fifth panels are made of rollable material for cost effectiveness, but the first and second panels are not made of rollable material. In the embodiment shown, the weaker panels between the stiffer first and second panels include a total of four weaker panels, namely, fifth, sixth, seventh, and eighth weaker panels between the two stiffer first and second panels that engage the sun visors. 
     The sunshade also has a cutout area  59  to accommodate the automobile&#39;s rear view mirror. The portions  60  of sunshade  50  that are immediately adjacent to rearview mirror cutout  59  are preferably highly bendable, and flexible and resilient enough such that when the user is installing the sunshade within the windshield of his car or truck, those portions bend sufficiently to allow the sunshade to be installed around the rear view mirror  84  ( FIG. 7 ). This allows cutout  59  to be narrower from side to side and/or from top to bottom than is the rear view mirror  84 , thus allowing the sunshade  50  to block more of the sun from coming in than if the cutout  59  were larger than the mirror. The thin cardboard strips  22  of the exemplary embodiment are flexible enough yet resilient enough to serve those functions. Alternatively, the cardboard strips  22  can stop short of the top edge  64  of the sunshade within the vicinity of the rear view mirror such that portions  60  adjacent the rear view mirror contain only, e.g., thermal bubble wrap material and no cardboard. In this way, portions  60  are made to be the most flexible portions of sunshade  50 , allowing for even easier installation around the rear view mirror. 
       FIG. 4  is a sectional view of the automobile sunshade  50  of  FIG. 3  taken along section line  4 - 4 ′. 
       FIG. 5  is a closeup view of the left side of the sunshade  50  section of  FIG. 4 . Sunshade  50  will fold along fold lines  57  between cardboard strips  22  and foamboard panels  30 . 
       FIG. 6  is a sectional view of the automobile sunshade of  FIG. 5  with the sunshade nearly completely folded for storage. In its folded position, the various panels  52 ,  54  of the sunshade are held together in a stacked relation by the flexible and foldable material, namely insulating mylar sheets  10  and  12  in the embodiment, which extends between and over both the standard or weakly reinforced panels  52  and the strongly reinforced panels  54 . The mylar sheets  10 ,  12  thus act as hinges allowing the sunshade to be folded along fold lines  57 . 
       FIG. 7  is a perspective view showing the sunshade  50  of  FIG. 3  installed in the windshield of an automobile. The user starts with the automobile&#39;s sun visors  82  in their unused or “up” positions, and places sunshade  50  behind (underneath) the windshield of the automobile. The user can either slide the sunshade up underneath the rear view mirror  84  from below, or can temporary bend the flexible portions  60  away so as to fit the sunshade around the mirror. The user then folds down the visors  82  so as to retain upwardly extending tabs  58  in place. The sun visors thus engage vertically extending heavily reinforced panels  54  which are sufficiently strong to hold sunshade  50  in place, and which are significantly stronger than the weakly reinforced panels  52 . The heavily reinforced panels  54  are preferably at least three times as stiff as the other panels  52  including the panels immediately adjacent to the reinforced and sun-visor-engaging panels  54 . 
       FIG. 8  is a top perspective closeup of one corner of the sunshade of  FIG. 3  but with the top cover  12  and edging  56  removed for clarity of illustration. Cardboard strips  22  can extend all the way to the bottom edge  62  and the top edge  64  ( FIG. 3 ) of sunshade  50 . In contrast, foamboard panels  30  do not extend all the way to the top and bottom edges  62 ,  64  of sunshade  50 . In the exemplary embodiment, foamboard panels  30  extend to within approximately 1 to 1½ inches of the periphery but do not extend to the periphery. 
       FIG. 9  is a top perspective view of the sunshade  50  of  FIG. 8  showing edging  56  being applied and stitched thereto. The stitching  55  penetrates the top and bottom sheets  10 ,  12 , and penetrates the edging material  56  and the cardboard stiffening strips  22  but does not penetrate the foamboard stiffener panels  30  because those stiffener panels do not reach the sunshade&#39;s edge. 
       FIG. 10  illustrates a second embodiment.  FIG. 10  is a top perspective closeup of one corner of a sunshade  150  having reinforced panels with the top cover  12  and edging  56  removed for clarity of illustration, similar to the view of  FIG. 8 . In this embodiment instead of a foamboard panel  30  used as the stiffener panel, the reinforced panel  154  includes a strip of spring material  130  such as spring metal, and more particularly, spring steel, affixed to a carrier substrate. The spring material could be any material with springy resilience, preferably that bends significantly without breaking, including various types of plastic. The carrier substrate could be a cardboard strip  22  similar to the other stiffening strips  22  in the sunshade. The spring metal  130  is thus the stiffener panel. The spring metal is preferably affixed to the strip by adhesive such as a spray adhesive or a hot melt adhesive, but could be affixed by other means including but not limited to riveting. As with the first embodiment, the sunshade  150  could include two such reinforced panels  154 , each of which engages a sun visor, with weaker panels  152  therebetween that are thinner, lighter, not as stiff, and less expensive. The reinforced panels  154  engaging the sun visors are sufficient to hold up sunshade  150  including weaker panels  152  in the sunshade&#39;s proper position underneath the windshield of an automobile even after repeated use including repeated folding and unfolding, and repeated prolonged exposure to the sun. As with the foamboard panels  30  of the prior embodiment, the strips of spring steel  130  do not extend all the way to the top and bottom edges of the sunshade, and the edging material  56  does not cover the spring steel  130  and the edging stitching  55  does not penetrate the spring steel. In an exemplary embodiment, the strips of spring steel  130  extend to within three inches of the top and bottom edges of the sunshade, and preferably to within about 1 to 1½ inches of the top and bottom edges, but do not extend all the way to the top and bottom edges of the sunshade. More generally, strips  130  could be of any material that is significantly stiffer than the material of which the weaker panels are made. The strips of spring steel  130  can be fed into a laminating section at the same time as the cardboard strips  22  as in  FIG. 1 , or could be affixed to the sunshade blank  32  after lamination and cutting. 
     It is not strictly necessary that the stiffening panels, which can be either foamboard panels  30  or spring metal strings  130  or other stiffening material, extend all the way up to engage the sun visors. Rather, the stiffening panels could extend close to the sun visors but not all the way thereto. In that case the stiffening panels still provide enough support to keep the sunshade from dropping or sagging even after much use, with the upwardly extending tabs  58  being flexible enough to allow the user to bend those tabs for slightly easier installation into position underneath the windshield of an automobile. 
     It is also not strictly necessary that the sunshade include either upwardly extending tabs  58  or rear view mirror cutout  59 . In another possible embodiment the sunshade does not have either one or both of those features. The sunshade could therefore be a folding square panel or nearly square panel that extends high enough to engage the sun visors and/or the rear view mirror. However, tabs  58  and rear view mirror cutout  59  add to the easy of placing sunshade  50  into the windshield of an automobile and later removing it. 
     Furthermore, it is not strictly necessary that the materials be affixed together via a method that would traditionally be considered a lamination process. The materials could be affixed together by rivets, spot heat welding, staples, stitching, or other methods. 
     It is also not strictly necessary that the sunshade include cardboard strips  22 . The material that will form the top and bottom covers  10 ,  12  could be sufficiently strong for panels  52  as those materials are sourced, and fold lines could be stamped, routed, laser ablated, or otherwise formed into that material to define a number of panels with fold lines between those panels. In such an embodiment, the major components of the sunshade would be top and bottom covers that themselves define a number of panels foldably connected together, with selected ones of those panels being reinforced by the addition of stiffener material therebetween. 
     It will be understood that the terms “generally,” “approximately,” “about,” “substantially,” “parallel,” and “coplanar” as used within the specification and the claims herein allow for a certain amount of variation from any exact dimensions, measurements, and arrangements, and that those terms should be understood within the context of the description and operation of the invention as disclosed herein. 
     All features disclosed in the specification, including the claims, abstract, and drawings, and all the steps in any method or process disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in the specification, including the claims, abstract, and drawings, can be replaced by alternative features serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
     It will be appreciated that the term “present invention” as used herein should not be construed to mean that only a single invention having a single essential element or group of elements is presented. Similarly, it will also be appreciated that the term “present invention” encompasses a number of separate innovations which can each be considered separate inventions. Although the present invention has thus been described in detail with regard to the preferred embodiments and drawings thereof, it should be apparent to those skilled in the art that various adaptations and modifications of the present invention may be accomplished without departing from the spirit and the scope of the invention. Accordingly, it is to be understood that the detailed description and the accompanying drawings as set forth hereinabove are not intended to limit the breadth of the present invention, which should be inferred only from the following claims and their appropriately construed legal equivalents.