Abstract:
A method of manufacturing roofing shingles comprises the steps of: coating a continuously supplied shingle mat with roofing asphalt to make an asphalt-coated sheet, the asphalt-coated sheet having at least one prime portion and at least one headlap portion, varying the thickness of the asphalt-coated sheet such that the at least one prime portion of the asphalt-coated sheet has a first thickness and the headlap portion has a second thickness, the thickness of the asphalt-coated sheet being varied by passing the asphalt-coated sheet through compression rollers, applying granules onto the asphalt-coated sheet to form a granule-covered sheet, and cutting the granule-covered sheet into shingles.

Description:
TECHNICAL FIELD 
     This invention relates to roofing shingles. More particularly, this invention relates to roofing shingles manufactured with more efficient use of raw materials. 
     BACKGROUND OF THE INVENTION 
     A common method for the manufacture of asphalt shingles is the production of a continuous strip of asphalt shingle material followed by a shingle cutting operation which cuts the material into individual shingles. 
     In the production of the continuous strip of asphalt shingle material, a substrate such as an organic felt or a glass fiber mat is passed into contact with a coater containing liquid asphalt to form a tacky asphalt coated strip. Subsequently, the hot asphalt coated strip is passed beneath one or more granule applicators which apply the protective surface granules to portions of the asphalt coated strip to form a granule coated sheet. The granule coated sheet is cooled and subsequently cut into individual shingles. 
     In the manufacturing process, the asphalt coated strip is conceptually divided into an equal number of prime lanes, and headlap lanes. The prime lanes receive an application of prime granules while the headlap lanes receive an application of headlap granules. It would be advantageous if shingles could be manufactured with more efficient use of raw materials. 
     SUMMARY OF THE INVENTION 
     The above objects as well as other objects not specifically enumerated are achieved by a method of manufacturing roofing shingles. The method comprises the steps of: coating a continuously supplied shingle mat with roofing asphalt to make an asphalt-coated sheet, the asphalt-coated sheet having at least one prime portion and at least one headlap portion, varying the thickness of the asphalt-coated sheet such that the at least one prime portion of the asphalt-coated sheet has a first thickness and the headlap portion has a second thickness, the thickness of the asphalt-coated sheet being varied by passing the asphalt-coated sheet through compression rollers, applying granules onto the asphalt-coated sheet to form a granule-covered sheet, and cutting the granule-covered sheet into shingles. 
     According to this invention there is also provided a method of manufacturing roofing shingles. The method comprises the steps of: coating a continuously supplied shingle mat with roofing asphalt to make an asphalt-coated sheet, the asphalt-coated sheet having at least one prime portion and at least one headlap portion, varying the thickness of the asphalt-coated sheet such that the at least one prime portion of the asphalt-coated sheet has a first thickness and the headlap-portion has a second thickness, the thickness of the asphalt-coated sheet being varied by passing the asphalt-coated sheet under an auxiliary coater, applying granules onto the asphalt-coated sheet to form a granule covered sheet, and cutting the granule-covered sheet into shingles. 
     According to this invention there is also provided a method of manufacturing roofing shingles. The method comprises the steps of: coating a continuously supplied shingle mat with roofing asphalt to make an asphalt-coated sheet, the asphalt-coated sheet having at least one prime portion and at least one headlap portion, varying the thickness of the asphalt-coated sheet such that the at least one prime portion of the asphalt-coated sheet has a first thickness and the headlap portion has a second thickness, applying a film to the at least one headlap portion of the asphalt-coated sheet, applying granules onto the at least one prime portion of the asphalt-coated sheet, and cutting the sheet into shingles. 
     According to this invention there is also provided an apparatus for manufacturing roofing shingles, the roofing shingles having at least one prime portion and at least one headlap portion. The apparatus comprises an asphalt coater configured to receive a shingle mat traveling in a machine direction. The asphalt coater is configured to coat the shingle mat with asphalt. At least one compression roller is positioned downstream from the asphalt coater. The at least one compression roller is configured to receive and compress the asphalt-coated sheet to the extent that excess asphalt is squeezed from the asphalt-coated sheet and the at least one prime portion of the asphalt-coated sheet forms a first thickness and the headlap portion forms a second thickness. At least one granule blender is positioned downstream from the at least one compression roller. The at least one granule blender is configured to apply granules onto the asphalt-coated sheet. A drum is positioned downstream from the at least one granule blender. The drum is configured to press the granules into the granule-covered sheet and remove the granules which are not adhered to the granule-covered sheet. A cutter is positioned downstream from the at least one granule blender. The cutter is configured to cut the granule-covered sheet into shingles. 
     According to this invention there is also provided an apparatus for manufacturing roofing shingles, the roofing shingles having at least one prime portion and at least one headlap portion. The apparatus comprises an asphalt coater configured to receive a shingle mat traveling in a machine direction. The asphalt coater is configured to coat the shingle mat with asphalt. At least one auxiliary coater is positioned downstream from the asphalt coater. The at least one auxiliary coater is configured to receive the shingle mat traveling in the machine direction and impart additional asphalt material onto the shingle mat such that the at least one prime portion of the asphalt-coated sheet forms a first thickness and the headlap portion forms a second thickness. At least one granule blender is positioned downstream from the at least one auxiliary coater. The at least one granule blender is configured to apply granules onto the asphalt-coated sheet. A drum is positioned downstream from the at least one granule blender. The drum is configured to press the granules into the granule-covered sheet and remove the granules which are not adhered to the granule-covered sheet. A cutter is positioned downstream from the at least one granule blender. The cutter is configured to cut the granule-covered sheet into shingles. 
     According to this invention there is also provided an apparatus for manufacturing roofing shingles, the roofing shingles having at least one prime portion and at least one headlap portion. The apparatus comprises an asphalt coater configured to receive a shingle mat traveling in a machine direction. The asphalt coater is configured to coat the shingle mat with asphalt. At least one compression roller is positioned downstream from the asphalt coater. The at least one compression roller is configured to receive and compress the asphalt-coated sheet to the extent that excess asphalt is squeezed from the asphalt-coated sheet and the at least one prime portion of the asphalt-coated sheet forms a first thickness and the headlap portion forms a second thickness. At least one film application unit is positioned downstream from the at least one compression roller. The at least one film application unit is configured to receive the shingle traveling in the machine direction and apply a film to the at least one headlap portion of the asphalt-coated sheet. At least one granule blender is positioned downstream from the at least one film application unit. The at least one granule blender is configured to apply granules onto the asphalt-coated sheet. A drum is positioned downstream from the at least one granule blender. The drum is configured to press the granules into the granule-covered sheet and remove the granules which are not adhered to the granule-covered sheet. A cutter is positioned downstream from the at least one granule blender. The cutter is configured to cut the granule-covered sheet into shingles 
     According to this invention there is also provided a method of manufacturing roofing shingles. The method comprises the steps of: coating a continuously supplied shingle mat with roofing asphalt to make an asphalt-coated sheet, the asphalt-coated sheet having at least one prime portion and at least one headlap portion, passing the asphalt-coated sheet through a thickness control mechanism such that the at least one prime portion of the asphalt coated-sheet has a prime portion weight and the headlap portion has a headlap portion weight, measuring the weight of the at least one prime portion and the at least one headlap portion in both the machine direction and the cross machine direction downstream from the thickness control mechanism, adjusting the thickness control mechanism to control the weight of the asphalt-coated sheet to achieve a desired weight, applying granules onto the at least one prime portion of the asphalt-coated sheet, and cutting the granule-covered sheet into shingles. 
     Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the invention, when read in light of the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic elevational view, partially in cross section, of a portion of an apparatus for making shingles according to the method of the invention. 
         FIG. 2  is a schematic plan view of a portion of the apparatus illustrated in  FIG. 1 , taken along the line  2 - 2 , showing a portion of the asphalt-coated sheet. 
         FIG. 3  is a side elevational view of the compression rolls, taken along the line  3 - 3 , of  FIG. 1 . 
         FIG. 4  is a side elevational view, in cross-section, of the asphalt-coated sheet downstream from the compression rolls of  FIG. 3 . 
         FIG. 5  is a plan view, in elevation, of a shingle according to one embodiment of the invention. 
         FIG. 6  is a side elevational view, in cross-section, of the shingle of  FIG. 5 . 
         FIG. 7  is a schematic elevational view, partially in cross section, of a second embodiment of an apparatus for making shingles, the apparatus having an auxiliary coater. 
         FIG. 8  is a side elevational view of the compression rolls, taken along the line  8 - 8 , of  FIG. 7 . 
         FIG. 9  is a side elevational view, in cross-section, of the asphalt-coated sheet downstream from the compression rolls of  FIG. 8 . 
         FIG. 10  is a schematic elevational view, partially in cross section, or a third embodiment of an apparatus for making shingles, the apparatus having an asphalt removal unit. 
         FIG. 11  is a side elevational view of the compression rolls, taken along the line  11 - 11 , of  FIG. 10 . 
         FIG. 12  is a side elevational view, in cross-section, of the asphalt-coated sheet downstream from the compression rolls of  FIG. 10 . 
         FIG. 13  is a schematic elevational view, partially in cross section, of a fourth embodiment of an apparatus for making shingles, the apparatus having a laminator. 
         FIG. 14  is a side elevational view of the compression rolls, taken along the line  14 - 14 , of  FIG. 13 . 
         FIG. 15  is a side elevational view, in cross-section, of the asphalt-coated sheet downstream from the compression rolls of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Composite shingles, such as asphalt shingles, are a commonly used roofing product. Asphalt shingle production generally includes feeding a base material from an upstream roll and coating it first with a filled roofing asphalt material, then a layer of granules. The base material is typically made from a fiberglass mat provided in a continuous shingle membrane or sheet. It should be understood that the base material can be any suitable support material. 
     The filled roofing asphalt material is added to the continuous shingle membrane for strength and improved weathering characteristics. It should be understood that the filled roofing asphalt material can include any suitable material, preferably low in cost, durable, and resistant to fire. 
     Composite shingles typically have a headlap region and a prime region. The headlap region may be ultimately covered by adjacent shingles when installed upon a roof. The prime region will be ultimately visible when the shingles are installed upon a roof. 
     The granules deposited on the composite material shield the filled roofing asphalt material from direct sunlight, offer resistance to fire, and provide texture and color to the shingle. The granules generally involve at least two different types of granules. Headlap granules are applied to the headlap region. Headlap granules are relatively low in cost and primarily serve the functional purposes of protecting the underlying asphalt material, balancing sheet weight and preventing overlapping shingles from sticking to one another. Colored granules or other prime granules are relatively expensive and are applied to the shingle at the prime regions. Prime granules are disposed upon the asphalt strip for both the functional purpose of protecting the underlying asphalt strip and for the purpose of providing an aesthetically pleasing appearance of the roof. 
     The layers of granules are typically applied with one or more granule applicators, such as pneumatic blenders, to the asphalt material covering the continuous shingle membrane. The pneumatic blender is a type of granule applicator known in the art. The granules can be applied to the continuous shingle membrane in color patterns to provide the shingles with an aesthetically pleasing appearance. The granules optionally can include anti-microorganism granules, such as copper granules, to inhibit the growth of algae, fungus, and/or other microorganisms. 
     The description and drawings disclose a method for manufacturing an asphalt shingle having a variable thickness. Referring now to the drawings, there is shown in  FIG. 1  an apparatus  10  for manufacturing asphalt-based shingles according to the invention. The illustrated manufacturing process involves passing a continuous sheet in a machine direction (indicated by an arrow  12 ) through a series of manufacturing operations. The sheet usually moves at a speed from about 300 feet/minute to about 800 feet/minute. However, other speeds can be used. 
     In a first step of the manufacturing process, a continuous sheet of shingle mat  14  is payed out from a roll (not shown). The shingle mat  14  can be any type of substrate known for use in reinforcing asphalt-based roofing shingles, such as a nonwoven web of glass fibers. The shingle mat  14  is fed through a coater  16  where a coating of asphalt  18  is applied to the top and bottom of the shingle mat  14 . The asphalt coating  18  can be applied in any suitable manner. In the illustrated embodiment, the shingle mat  14  contacts a supply of hot, melted asphalt  18  to completely cover the shingle mat  14  with a tacky coating of asphalt  18 . However, in other embodiments, the asphalt coating  18  could be sprayed on, rolled on, or applied to the shingle mat  14  by other means. Typically the filled roofing asphalt material is highly filled with a ground mineral filler material, amounting to at least about 60 percent by weight of the asphalt/filler combination. The shingle mat  14  exits the coater  16  as an asphalt-coated sheet  20 . The asphalt coating  18  on the asphalt-coated sheet  20  remains hot. 
     The asphalt-coated sheet  20  is shown in more detail in  FIG. 2 . As shown, the asphalt-coated sheet  20  for the three-wide apparatus  10  comprises six distinct regions or lanes including three headlap lanes h 1 , h 2 , and h 3 , and three prime lanes p 1 , p 2 , and p 3 . An exemplary roofing shingle is shown by a phantom line  22  and may be cut from asphalt-coated sheet  20  as shown. In this manner, three roofing shingles of any length desired may be cut from each such length of asphalt-coated sheet  20 . Each shingle  22  would contain one headlap lane h 1 , h 2 , or h 3 , and one respective adjacent prime lane p 1 , p 2 , or p 3 . Accordingly, the shingle  22  includes a headlap region  26  and a prime region  24 . 
     The headlap region  24  of the shingle  22  is that portion which is covered by adjacent shingles when the shingle  22  is ultimately installed upon a roof. The prime region  26  of the shingle  22  is that portion which remains exposed when the shingle  22  is ultimately installed upon a roof. 
     In this embodiment, the shingle  22  is cut from the asphalt-coated sheet  20  to be approximately three feet long by one foot wide. As further shown in  FIGS. 2 and 6 , the shingle  22  includes two cut-out regions  28  which define three tabs  30 . It will be apparent to one skilled in the art that the asphalt-coated sheet  20  may be manufactured having a wide variety of widths to allow different numbers of shingles to be cut therefrom. For example, some roofing shingle manufacturing plants use an asphalt-coated sheet (not shown) which is sufficiently wide to allow four or more one-foot wide shingles to be cut therefrom. Such a wider asphalt-coated sheet would include an additional headlap region, and an additional prime region. One skilled in the art will also recognize that roofing shingles of different sizes, i.e. roofing shingles having different lengths and/or widths, may be cut from the asphalt-coated sheet  20 . 
     As will be appreciated by one skilled in the art, while the Figures illustrate a 3-tab strip shingle such as that shown in  FIG. 5  and process/apparatus for manufacturing such a strip shingle, the same principles may be applied to a laminated shingle; i.e. the headlap portion of the laminate shingle may be thinner than the tab region, or vice-versa. Furthermore, any of the overlay and/or underlay and/or headlap regions of the laminated shingle may be thinned according the principles of the instant invention to accomplish reduction of asphalt in unnecessary regions. In one such embodiment, the instant invention is used to remove excess asphalt from between the layers of the laminated region of the shingle in the exposed area of the laminate shingle. 
     The resulting asphalt-coated sheet  20 , including headlap lanes h 1 , h 2  and h 3  and prime lanes, p 1 , p 2  and p 3 , is then passed between a top compression roll  32  and a bottom compression roll  34 . In this embodiment, the top compression roll  32  is a drum rotating about axis a 1 . Similarly, the bottom compression roll  34  is a drum rotating about axis a 2 . Referring again to  FIG. 1 , as the asphalt-coated sheet  20  feeds between the top compression roll  32  and the bottom compression roll  34 , the asphalt-coated sheet  20  is compressed and excess asphalt is squeezed from the asphalt-coated sheet  20 . The excess asphalt is the returned to the coater  16 . In an alternative embodiment (not shown), the compression rolls  32 ,  34  are provided at the applicator  18 , versus the downstream position as shown in the Figures, thereby eliminating a set of rollers. 
     As shown in  FIG. 3 , the top compression roll  32  comprises different roll regions having different roll diameters that correspond to the headlap and prime lanes of the asphalt-coated sheet  20 . In this embodiment, the top compression roll  32  includes roll regions  40 ,  42  and  44 . Roll region  40  has a roll diameter d 1 , roll region  42  has a roll diameter d 2  and roll region  44  has a roll diameter d 3 . The top compression roll  32  also includes roll regions  46 ,  48  and  50 . Roll region  46  has a roll diameter d 4 , roll region  48  has a roll diameter d 5  and roll region  50  has a roll diameter d 6 . 
     In this embodiment as further shown in  FIG. 3 , the bottom compression roll  34  has a bottom roll region  52 . The bottom roll region  52  extends across the entire width of the roll  34 . The bottom roll region  52  has a bottom roll diameter b 1 . 
     In operation, as the asphalt-coated sheet  20  passes between the top compression roll  32  and the bottom compression roll  34 , headlap lane h 1  of the asphalt-coated sheet  20  passes between roll region  40  of the top compression roll  32  and roll region  52  of the bottom compression roll  34 . As the headlap lane h 1  passes between roll region  40  of the top compression roll  32  and roll region  52  of the bottom compression roll  34 , headlap lane hl is compressed to thickness t 1 . In a similar manner, as headlap lanes h 2  and h 3  pass between roll regions  42  and  44  of the top compression roll  32  and roll region  52  of the bottom compression roll  34 , headlap lanes h 2  and h 3  are compressed to thicknesses t 2  and t 3 , respectfully. Also in a similar manner, as prime lanes p 1 , p 2  and p 3  pass between roll regions  46 ,  48  and  50  of the top compression roll  32  and roll region  52  of the bottom compression roll  34 , prime lanes p 1 , p 2  and p 3  are compressed to thicknesses t 4 , t 5  and t 6 , respectfully. In this embodiment as shown in  FIG. 3 , the d 1 , d 2  and d 3  diameters of roll regions  40 ,  42  and  44 , corresponding to headlap lanes h 1 , h 2  and h 3 , are the same. In another embodiment, the d 1 , d 2  and d 3  diameters of roll regions  40 ,  42  and  44  could be different. Similarly, in this embodiment as shown in  FIG. 3 , the d 4 , d 5  and d 6  diameters of roll regions  46 ,  48  and  50 , corresponding to prime lanes p 1 , p 2  and p 3 , are the same. In another embodiment, the d 4 , d 5  and d 6  diameters of roll regions  46 ,  48  and  50  could be different. 
     While the top compression roll  32  shown in  FIG. 3  illustrates various diameters d 1 , d 2 , d 3 , d 4 , d 5  and d 6  and the bottom compression roll  34  illustrates a constant diameter b 1 , in another embodiment the top compression roll  32  can have a constant diameter and the bottom compression roll  34  can have various diameters. 
     The asphalt-coated sheet  20  exits from the top compression roll  32  and the bottom compression roll  34  as a formed sheet  54  as shown in  FIG. 4 . Formed sheet  54  includes headlap lanes h 1 , h 2  and h 3  having thicknesses t 1 , t 2  and t 3 , respectfully. Formed sheet  54  also includes prime lanes p 1 , p 2  and p 3  having thicknesses t 4 , t 5  and t 6 , respectfully. In this embodiment, thicknesses t 1 , t 2  and t 3  are in a range from about 20 mils to about 70 mils. Alternatively, the thicknesses t 1 , t 2  and t 3  could be more than 70 mils or less than 20 mils. In this embodiment, thicknesses t 4 , t 5  and t 6  are in a range from about 40 mils to about 100 mils. Alternatively, the thicknesses t 4 , t 5  and t 6  could be more than 100 mils or less than 40 mils. 
     As shown in  FIGS. 5 and 6 , after the roofing shingle  22  has been cut from the formed sheet  54 , the roofing shingle  22  includes headlap lane h 1  and prime lane p 1 . Headlap lane h 1  has thickness t 1  and prime lane p 1  has thickness t 4 . In this embodiment, the thickness t 1  is thinner than the thickness t 4 . In another embodiment, the thickness t 1  may be the same as the thickness t 4  or the thickness t 1  may be more than the thickness t 4 . In one embodiment, the difference between the thickness t 1  and the thickness t 4  is at least 1 mil. In another embodiment, the difference between the thickness t 1  and thickness t 4  can be 1 mil or less than 1 mil. 
     As previously discussed, compression of the asphalt-coated sheet  20  between the top compression roll  32  and the bottom compression roll  34  squeezes excess asphalt material  18  from the asphalt-coated sheet  20 . In this embodiment, the excess asphalt material  18  is recovered and recycled. By squeezing excess asphalt material  18  from the asphalt-coated sheet  20 , a smaller amount of raw materials is necessary for the manufacture of composite shingles. 
     In addition to using a smaller amount of raw materials, the weight of the shingles can be reduced by squeezing excess asphalt material  18  from the asphalt-coated sheet  20 . By reducing the weight of the shingles, the cost of raw materials and transportation of the manufactured shingles will be reduced. The excess asphalt material  18  can be squeezed from the asphalt-coated sheet by a thickness control mechanism. In this embodiment the thickness control mechanism comprises the top compression roll  32  and the bottom compression roll  34 . In another embodiment, the thickness control mechanism can be any other assembly or mechanism sufficient to control the thickness of the asphalt-coated sheet  20 . Referring again to  FIG. 4 , the thicknesses t 1 , t 2 , t 3 , t 4 , t 5  and t 6  formed by the top compression roll  32  and the bottom compression roll  34  can be controlled to provide the desired weights of the prime portions  26  and the headlap portions  24  in both the machine direction and the cross machine direction. In one embodiment, a shingle could have a prime portion  26  having a prime portion weight per square foot and a headlap portion  26  having a lesser headlap portion weight per square foot. Referring again to  FIG. 1 , as the formed sheet  54  exits the top compression roll  32  and the bottom compression roll  34 , the weight of the formed sheet  54  is measured. The weight of the formed sheet  54  can be determined by any method, such as for example measuring the density of the asphalt using a scanner, suitable to determine the weight of the formed sheet  54 . By measuring the weight of the formed sheet  54 , the measured weight of the formed sheet  54  can be compared to the desired weight of the formed sheet  54  and adjustments, if necessary, can be made to the top and bottom compression rolls  32  and  34  to produce the desired thicknesses t 1 , t 2 , t 3 , t 4 , t 5  and t 6 . It is to be understood that different shingle products can have different desired weights for the prime portions and the headlap portions. While in this embodiment the weight of the formed sheet  54  is determined downstream from the top and bottom compression rolls  32  and  34  respectfully, and it is to be understood that the weight of the shingle can be determined at other locations, such as for example after the granules have been deposited on the formed sheet  54 , in the process. 
     An example of a lightweight shingle having varying weight regions is a shingle of the type disclosed in U.S. patent application Ser. No. 11/582,285 filed Oct. 17, 2006, which is hereby incorporated by reference, in its entirety. The disclosed lightweight shingle reduces the overall shingle weight by incorporating low density, lightweight headlap granules into the headlap region. In a preferred embodiment, a lightweight granule is used in combination with a thin headlap as described herein. In yet a further embodiment, the headlap granules are of a larger dimension than the prime granules to accomplish a more uniform overall sheet thickness, and more preferably the headlap granule comprises a lightweight granule. 
     Referring again to  FIG. 1 , the resulting multi-leveled, asphalt-coated formed sheet  54  is then passed beneath a series of granule applicators, hoppers or blenders  56  and  58  for dispensing granules to an upper surface of the formed sheet  54 . The granule applicators  56  and  58  can be of any type suitable for depositing granules onto the formed sheet  54 . An example of a granule blender is a granule blender of the type disclosed in U.S. Pat. No. 5,599,581 to Burton et al., which is hereby incorporated by reference, in its entirety. Additionally, a granule valve such as the granule valve disclosed in U.S. Pat. No. 6,610,147 to Aschenbeck may also be used. U.S. Pat. No. 6,610,147 to Aschenbeck is also incorporated by reference in its entirety. Although two granule blenders  56  and  58  are shown in the embodiment illustrated in  FIG. 1 , any suitable number and configuration of granule blenders can be used. 
     For example, a series of two blenders can be used, wherein the granule blender  56  can be used to deposit prime granules  57  on the prime lanes p 1 , p 2  and p 3 . Similarly, the granule blender  58  can be used to apply headlap granules  59  on the headlap lanes h 1 , h 2  and h 3 . Applying prime granules  57  and headlap granules defines a granule-covered sheet  62 . In another embodiment, additional granule blenders can be used for additional granule drops, such as different colors, sharp demarcations and background granules. 
     As shown in  FIG. 1 , after all the granules are deposited on the asphalt-coated sheet  20 , the granule-covered sheet  62  is turned around a slate drum  64  to press the granules into the asphalt coating and to temporarily invert the granule-covered sheet  62  so that the excess granules fall off. The excess granules are recovered and reused. The granule-covered sheet  62  is subsequently fed through a cutter  74  that cuts the granule-covered sheet  62  into individual shingles  22 . The cutter  74  may be any type of cutter, such as for example a rotary cutter, sufficient to cut the granule-covered sheet  62  into individual shingles  22 . 
     In another embodiment, apparatus  110  for manufacturing an asphalt-based roofing shingle is shown in  FIG. 7 . An asphalt-coated sheet  120 , including headlap lanes h 1 , h 2  and h 3  and prime lanes, p 1 , p 2  and p 3 , is fed between a top compression roll  132  and a bottom compression roll  134 . In this embodiment, the top compression roll  132  and the bottom compression roll  134  are rotating drums as shown in  FIG. 8 . Referring again to  FIG. 7 , as the asphalt-coated sheet  120  feeds between the top compression roll  132  and the bottom compression roll  134 , the asphalt-coated sheet  120  is compressed and excess asphalt is squeezed from the asphalt-coated sheet  120 . 
     As shown in  FIG. 8 , the top compression roll  132  comprises a single roll region  140  having a consistent roll diameter d 100 . Similarly, the bottom compression roll  134  has a single bottom roll region  152  having a consistent bottom roll diameter b 100 . 
     Referring again to  FIG. 7 , in operation, as the asphalt-coated sheet  120  passes between the top compression roll  132  and the bottom compression roll  134 , the headlap lanes h 1 , h 2  and h 3  of the asphalt-coated sheet  120 , and the prime lanes p 1 , p 2 , and p 3  pass between roll region  140  of the top compression roll  132  and roll region  152  of the bottom compression roll  134 . As the headlap lanes h 1 , h 2  and h 3  and the prime lanes p 1 , p 2 , and p 3  pass between roll region  140  of the top compression roll  132  and roll region  152  of the bottom compression roll  134 , the headlap lanes h 1 , h 2  and h 3  and the prime lanes p 1 , p 2 , and p 3  are compressed to thickness t 100 . In this embodiment, the top compression roll  132  and the bottom compression roll  134  compress the asphalt-coated sheet  120  to a uniform consistent thickness t 100 . 
     The asphalt-coated sheet  120  exits the compression of the top compression roll  132  and the bottom compression roll  134  as a formed sheet  154  as shown in  FIG. 7 . Formed sheet  154  includes headlap lanes h 1 , h 2  and h 3  and prime lanes p 1 , p 2  and p 3 , each having thicknesses t 100 . The formed sheet  154  passes under an auxiliary coater  170 . In this embodiment, the auxiliary coater  170  is configured to impart additional asphalt material  118  onto the top of the prime lanes p 1 , p 2 , and p 3  of the formed sheet  154 , forming an additional layer  122 , shown in  FIG. 9 . After depositing the additional layer  122  of asphalt material  118  on the top of the prime lanes p 1 , p 2 , and p 3 , the formed sheet  154  becomes layered sheet  172  as illustrated in  FIG. 9 . As shown in  FIG. 9 , the prime lanes p 1 , p 2  and p 3  have a thickness t 4 , t 5  and t 6 , respectfully. In this embodiment, thicknesses t 1 , t 2  and t 3  are in a range from about 20 mils to about 70 mils. Alternatively, the thicknesses t 1 , t 2  and t 3  could be more than 70 mils or less than 20 mils. In this embodiment, thicknesses t 4 , t 5  and t 6  are in a range from about 40 mils to about 100 mils. Alternatively, the thicknesses t 4 , t 5  and t 6  could be more than 100 mils or less than 40 mils. In this embodiment, the auxiliary coater  170  is a mechanism that sprays an additional layer  122  of asphalt material  118  onto the prime lanes p 1 , p 2 , and p 3 . Alternatively, the additional layer  122  of asphalt material  118  can be applied to the formed sheet  154  in another manner, such as by a dispenser or an extruder, or by any other manner sufficient to deposit an additional layer  122  of asphalt material  118  onto the prime lanes p 1 , p 2 , and p 3 . In one such embodiment, the additional asphalt  118  is a weathering asphalt, and the initial asphalt coating is a less weatherable asphalt, thereby further reducing the cost of the asphalt used in the shingle construction. Alternatively, the first asphalt utilizes a higher filler level and/or the additional asphalt  118  may include additional additives or comprise an adhesive material to retain the granules or provide impact resistance as described in commonly assigned U.S. Pat. No. 6,426,309, which is incorporated herein by reference in its entirety. 
     In yet another embodiment, apparatus  210  for manufacturing an asphalt-based roofing shingle is shown in  FIG. 10 . An asphalt-coated sheet  220 , including headlap lanes h 1 , h 2  and h 3  and prime lanes, p 1 , p 2  and p 3 , is fed between a top compression roll  232  and a bottom compression roll  234 . In this embodiment, the top compression roll  232  and the bottom compression roll  234  are rotating drums as shown in  FIG. 11 . Referring again to  FIG. 10 , as the asphalt-coated sheet  220  feeds between the top compression roll  232  and the bottom compression roll  234 , the asphalt-coated sheet  220  is compressed and excess asphalt is squeezed from the asphalt-coated sheet  220 . 
     As shown in  FIG. 11 , the top compression roll  232  comprises a single roll region  240  having a consistent roll diameter d 200 . Similarly, the bottom compression roll  234  has a single bottom roll region  252  having a consistent bottom roll diameter b 200 . 
     Referring again to  FIG. 10 , in operation, as the asphalt-coated sheet  220  passes between the top compression roll  232  and the bottom compression roll  234 , the headlap lanes h 1 , h 2  and h 3  of the asphalt-coated sheet  220 , and the prime lanes p 1 , p 2 , and p 3  pass between roll region  240  of the top compression roll  232  and roll region  252  of the bottom compression roll  234 . As the headlap lanes h 1 , h 2  and h 3  and the prime lanes p 1 , p 2 , and p 3  pass between roll region  240  of the top compression roll  232  and roll region  252  of the bottom compression roll  234 , the headlap lanes h 1 , h 2  and h 3  and the prime lanes p 1 , p 2 , and p 3  are compressed to thickness t 200 . In this embodiment, the top compression roll  232  and the bottom compression roll  234  compress the asphalt-coated sheet  220  to a uniform consistent thickness t 200 . 
     The asphalt-coated sheet  220  exits the compression of the top compression roll  232  and the bottom compression roll  234  as a formed sheet  254  as shown in  FIG. 10 . Formed sheet  254  includes headlap lanes h 1 , h 2  and h 3  and prime lanes p 1 , p 2  and p 3 , each having thicknesses t 200 . The formed sheet  254  passes under an asphalt remover  270 . In this embodiment, the asphalt remover  270  is configured to remove a layer of asphalt material from the top of the headlap lanes h 1 , h 2 , and h 3  of the formed sheet  254 . After removing a layer of asphalt material from the top of the headlap lanes h 1 , h 2 , and h 3 , the formed sheet  254  becomes layered sheet  272  as illustrated in  FIG. 12 . As shown in  FIG. 12 , the prime lanes p 1 , p 2  and p 3  have a thickness t 4 , t 5  and t 6 , respectfully. In this embodiment, thicknesses t 1 , t 2  and t 3  are in a range from about 20 mils to about 70 mils. Alternatively, the thicknesses t 1 , t 2  and t 3  could be more than 70 mils or less than 20 mils. In this embodiment, thicknesses t 4 , t 5  and t 6  are in a range from about 40 mils to about 100 mils. Alternatively, the thicknesses t 4 , t 5  and t 6  could be more than 100 mils or less than 40 mils. 
     In this embodiment as shown in  FIG. 10 , the asphalt remover  270  is a scraper having one or more scraping blades. In another embodiment, the asphalt remover  270  could be any mechanism, structure or assembly, such as an abrasive wheel or a suction device, sufficient to remove a layer of asphalt material from one or more of the top and/or bottom of the headlap lanes h 1 , h 2  and h 3 . Alternatively, the outboard lanes h 1  and h 3  may be reduced in thickness, or the center lane h 2  may be of reduced thickness. 
     In yet another embodiment, apparatus  310  for manufacturing an asphalt-based roofing shingle is shown in  FIG. 13 . A resulting asphalt-coated sheet  320 , including headlap lanes h 1 , h 2  and h 3  and prime lanes, p 1 , p 2  and p 3 , is then passed between a top compression roll  332  and a bottom compression roll  334 . In this embodiment, the top compression roll  332  and the bottom compression roll  334  are rotating drums as shown in  FIG. 14 . Referring again to  FIG. 13 , as the asphalt-coated sheet  320  feeds between the top compression roll  32  and the bottom compression roll  334 , the asphalt-coated sheet  320  is compressed and excess asphalt is squeezed from the asphalt-coated sheet  320 . 
     As shown in  FIG. 14 , the top compression roll  332  comprises different roll regions having different roll diameters that correspond to the headlap and prime lanes of the asphalt-coated sheet  320 . In this embodiment, the top compression roll  332  includes roll regions  340 ,  342  and  344 . Roll region  340  has a roll diameter d 301 , roll region  342  has a roll diameter d 302  and roll region  344  has a roll diameter d 303 . The top compression roll  332  also includes roll regions  346 ,  348  and  350 . Roll region  346  has a roll diameter d 304 , roll region  348  has a roll diameter d 305  and roll region  350  has a roll diameter d 306 . 
     In this embodiment as further shown in  FIG. 14 , the bottom compression roll  334  has a bottom roll region  352 . The bottom roll region  352  has a bottom roll diameter b 301 . 
     In operation, as the asphalt-coated sheet  320  passes between the top compression roll  332  and the bottom compression roll  334 , headlap lanes h 1  of the asphalt-coated sheet  320  passes between roll region  340  of the top compression roll  332  and roll region  352  of the bottom compression roll  334 . As the headlap lane h 1  passes between roll region  340  of the top compression roll  332  and roll region  352  of the bottom compression roll  334 , the headlap lane h 1  is compressed to thickness t 301 . In a similar manner, as headlap lanes h 2  and h 3  pass between roll regions  342  and  344  of the top compression roll  332  and roll region  352  of the bottom compression roll  334 , headlap lanes h 2  and h 3  are compressed to thicknesses t 302  and t 303 . Also in a similar manner, as prime lanes p 1 , p 2  and p 3  pass between roll regions  346 ,  348  and  350  of the top compression roll  332  and roll region  352  of the bottom compression roll  334 , prime lanes p 1 , p 2  and p 3  are compressed to thicknesses t 304 , t 305  and t 306 . In this embodiment as shown in  FIG. 14 , the d 301 , d 302  and d 303  diameters of roll regions  340 , 342  and  344 , corresponding to headlap lanes h 1 , h 2  and h 3 , are the same. In another embodiment, the d 301 , d 302  and d 303  diameters of roll regions  340 ,  342  and  344  could be different. Similarly, in this embodiment as shown in  FIG. 14 , the d 304 , d 305  and d 306  diameters of roll regions  346 ,  348  and  350 , corresponding to prime lanes p 1 , p 2  and p 3 , are the same. In another embodiment, the d 304 , d 305  and d 306  diameters of roll regions  346 ,  348  and  350  could be different. 
     The asphalt-coated sheet  320  exits the compression of the top compression roll  332  and the bottom compression roll  334  as a formed sheet  354  as shown in  FIG. 15 . Formed sheet  354  includes headlap lanes h 1 , h 2  and h 3  having thicknesses t 301 , t 302  and t 303 . Formed sheet  354  also includes prime lanes p 1 , p 2  and p 3  having thicknesses t 304 , t 305  and t 306 . In this embodiment, thicknesses t 301 , t 302  and t 303  are in a range from about 20 mils to about 70 mils. Alternatively, the thicknesses t 301 , t 302  and t 303  could be more than 70 mils or less than 20 mils. In this embodiment, thicknesses t 304 , t 305  and t 306  are in a range from about 40 mils to about 100 mils. Alternatively, the thicknesses t 304 , t 305  and t 306  could be more than 100 mils or less than 40 mils. 
     Referring again to  FIG. 13 , formed sheet  354  is then passed underneath a film application unit  380 . The film application unit  380  is configured to apply a film  382  to the headlap lanes h 1 , h 2 , and h 3 . The film  382  is configured to strengthen the headlap lanes h 1 , h 2  and h 3 . By applying the film  382  to the headlap lanes h 1 , h 2  and h 3 , the step of applying granules to the headlap lanes h 1 , h 2  and h 3  can be eliminated, thereby resulting in a more lightweight shingle. More lightweight shingles can result in reduced transportation costs and reduced labor costs. As shown in  FIG. 13 , the film  382  is made of a vinyl or PVC film. Alternatively, the film  382  can be another material, such as polyester, PVA polypropylene, metallic foil, fabric or any other material sufficient to strengthen the headlap lanes h 1 , h 2 , and h 3 . The film  382  can be made of fibers or reinforced with fibers. The film  382  can comprise a material that is tacky for the granules, or the film  382  can be a material to which the granules do not readily adhere. 
     After passing underneath the film application unit  380 , the formed sheet  354  becomes a filmed sheet  384 . The filmed sheet  384  passes beneath a granule hopper  356  for dispensing granules to the prime lanes p 1 , p 2  and p 3 . Although a single granule blender  356  is shown in the embodiment illustrated in  FIG. 13 , any suitable number and configuration of granule blenders, including an applicator for background granules, can be used. 
     As shown in  FIG. 13 , after the granules are deposited on the prime lanes p 1 , p 2 , and p 3  of the laminated sheet  384 , the granule-covered sheet  362  is turned around a slate drum  364  to press the granules into the asphalt coating and to temporarily invert the granule-covered sheet  362  so that the excess granules fall off. The excess granules are recovered and reused. The granule-covered sheet  362  is subsequently fed through a cutter  374  that cuts the granule-covered sheet  362  into individual shingles. 
     The principle and mode of operation of this invention have been described in its preferred embodiments. However, it should be noted that this invention may be practiced otherwise than as specifically illustrated and described without departing from its scope.