Patent Abstract:
A method for adjusting the track of a granule-coated sheet includes moving a granule-coated sheet around a drum. The granule-coated sheet includes first granules. A track of the granule-coated sheet is sensed at the drum. A first signal is generated when the granule-coated sheet has moved off a pre-designated track. Second granules are applied to a lane portion of the granule-coated sheet prior to the drum in response to the first signal. The second granules make the granule-coated sheet thicker in the lane portion relative to a thickness of the granule-coated sheet outside the lane portion.

Full Description:
BACKGROUND 
       [0001]    This invention relates to asphalt-based roofing materials. More particularly, this invention relates to methods and apparatus for adjusting the track of a granule-coated sheet. Asphalt-based roofing materials, such as roofing shingles, roll roofing, and commercial roofing, are installed on the roofs of buildings to provide protection from the elements, and to give the roof an aesthetically pleasing appearance. Typically, the roofing material is constructed of a substrate such as a glass fiber mat or an organic felt, an asphalt coating on the substrate, and a surface layer of granules embedded in the asphalt coating. 
         [0002]    A common method for the manufacture of asphalt shingles is the production of a continuous sheet of asphalt material followed by a shingle cutting operation which cuts the material into individual shingles. In the production of asphalt sheet material, either a glass fiber mat or an organic felt mat is passed through a coater containing hot liquid asphalt to form a tacky, asphalt-coated sheet. Subsequently, the hot asphalt-coated sheet is passed beneath one or more granule applicators which discharge protective and decorative surface granules onto portions of the asphalt sheet material. 
         [0003]    In the manufacture of colored shingles, two types of granules are typically employed. Headlap granules are granules of relatively low cost used for the portion of the shingle which will be covered on the roof. Colored granules or prime granules are of relatively higher cost and are applied to the portion of the shingle that will be exposed and visible on the roof. 
         [0004]    To provide a color pattern of pleasing appearance, the colored portion of the shingles may be provided with areas of different colors. Usually the shingles have a background color and a series of granule deposits of different colors or different shades of the background color. A common method for manufacturing the shingles is to discharge blend drops onto spaced areas of the tacky, asphalt-coated sheet. Background granules are then discharged onto the sheet and adhere to the tacky, asphalt-coated areas of the sheet between the granule deposits formed by the blend drops. The background granules are applied to the extent that the asphalt-coated sheet becomes completely covered with granules, thereby defining a granule-coated sheet. The granule-coated sheet is then turned around a slate drum to press the granules into the asphalt coating and to temporarily invert the sheet. 
         [0005]    The term “blend drop,” as used herein, refers to the flow of granules of different colors or different shades of color (with respect to the background color) that is discharged from a granule blend drop applicator onto the asphalt-coated sheet. The patch or assemblage of the blend drop granules on the asphalt-coated sheet is also referred to as the “blend drop.” 
         [0006]    One of the problems with conventional asphalt shingle manufacturing equipment is that the granule-coated sheet can wander or move laterally as it moves across the slate drum. The above notwithstanding, there remains a need in the art for an improved method of ensuring that the granule-coated sheet remains on its desired track and does not wander. 
       SUMMARY OF THE INVENTION 
       [0007]    The present application describes various embodiments of a method for adjusting the track of a granule-coated sheet. One embodiment of the method for adjusting the track of a granule-coated sheet includes moving a granule-coated sheet around a drum. The granule-coated sheet includes first granules. A track of the granule-coated sheet is sensed at the drum. A first signal is generated when the granule-coated sheet has moved off a pre-designated track. Second granules are applied to a lane portion of the granule-coated sheet prior to the drum in response to the first signal. The second granules make the granule-coated sheet thicker in the lane portion relative to a thickness of the granule-coated sheet outside the lane portion. 
         [0008]    In another embodiment, a granule applicator includes a granule hopper defining a granule outlet. A gate is movably mounted relative to the hopper. The gate is movable between a plurality of first open positions wherein granules may flow out of the granule outlet. The gate is also pivotally movable relative to the granule hopper between any of the plurality of first open positions and a plurality of pivoted positions. 
         [0009]    In another embodiment, a method for adjusting the track of a granule-coated sheet includes discharging granules from a granule dispenser on to an asphalt-coated sheet to define a granule-coated sheet. The granule-coated sheet is moved around a drum and a track of the granule-coated sheet is sensed at the drum. A first signal is generated when the granule-coated sheet has moved off a pre-designated track. The amount of granules discharged from the granule dispenser on to a lane portion of the granule-coated sheet is increased in response to the first signal. The increased amount of granules make the granule-coated sheet thicker in the lane portion relative to a thickness of the granule-coated sheet outside the lane portion. 
         [0010]    Other advantages of the method for adjusting the track of a granule-coated sheet will become apparent to those skilled in the art from the following detailed description, when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0011]    A complete appreciation of the invention and the many embodiments thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. 
           [0012]      FIG. 1  is a schematic view in elevation of an apparatus for manufacturing an asphalt-based roofing material according to the invention. 
           [0013]      FIG. 2  is a schematic side elevation view of a first embodiment of the tracking granule applicator illustrated in  FIG. 1 . 
           [0014]      FIG. 3  is an enlarged schematic plan view of a portion of the asphalt-coated sheet illustrated in  FIG. 1 , showing the two of the tracking granule applicators illustrated in  FIGS. 1 and 2 . 
           [0015]      FIG. 4  is a schematic plan view of a second embodiment of a tracking granule applicator. 
           [0016]      FIG. 5  is a schematic side elevation view of the second embodiment of the tracking granule applicator illustrated in  FIG. 4 . 
           [0017]      FIG. 6  is a schematic plan view of the gate of the second embodiment of a tracking granule applicator illustrated in  FIG. 4 , showing the gate in a second position. 
       
    
    
     DETAILED DESCRIPTION  
       [0018]    The present invention will now be described with occasional reference to the illustrated embodiments of the invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein, nor in any order of preference. Rather, these embodiments are provided so that this disclosure will be more thorough, and will convey the scope of the invention to those skilled in the art. 
         [0019]    Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
         [0020]    Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth as used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless otherwise indicated, the numerical properties set forth in the specification and claims are approximations that may vary depending on the desired properties sought to be obtained in embodiments of the present invention. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from error found in their respective measurements. 
         [0021]    As used in the description and the appended claims, the phrase “asphalt coating” is defined as any type of bituminous material suitable for use on a roofing material, such as asphalts, tars, pitches, or mixtures thereof. The asphalt may be either manufactured asphalt produced by refining petroleum or naturally occurring asphalt. The asphalt coating may include various additives and/or modifiers, such as inorganic fillers or mineral stabilizers, organic materials such as polymers, recycled streams, or ground tire rubber. Preferably, the asphalt coating contains asphalt and an inorganic filler or mineral stabilizer. 
         [0022]    As used in the description and the appended claims, the term “wander” is defined as any lateral movement; i.e., movement transverse to the machine direction  13 , of the granule-coated sheet  28  relative to the slate drum  30  as the granule-coated sheet  28  moves across the slate drum  30 . 
         [0023]    Laminated 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 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. 
         [0024]    Referring now to the drawings, there is shown in  FIG. 1  an apparatus  10  for manufacturing an asphalt-based roofing material, and more particularly for applying granules onto an asphalt-coated sheet. The illustrated manufacturing process involves passing a continuous sheet of substrate or shingle mat  12  in a machine direction  13  through a series of manufacturing operations. The sheet usually moves at a speed of at least about 200 feet/minute (61 meters/minute), and typically at a speed within the range of between about 450 feet/minute (137 meters/minute) and about 620 feet/minute (244 meters/minute). However, other speeds may be used. 
         [0025]    In a first step of the manufacturing process, the continuous sheet of shingle mat  12  is payed out from a roll  14 . The shingle mat  12  may be any type known for use in reinforcing asphalt-based roofing materials, such as a nonwoven web of glass fibers. Alternatively, the substrate may be a scrim or felt of fibrous materials such as mineral fibers, cellulose fibers, rag fibers, mixtures of mineral and synthetic fibers, or the like. 
         [0026]    The sheet of shingle mat  12  is passed from the roll  14  through an accumulator  16 . The accumulator  16  allows time for splicing one roll  14  of substrate to another, during which time the shingle mat  12  within the accumulator  16  is fed to the manufacturing process so that the splicing does not interrupt manufacturing. 
         [0027]    Next, the shingle mat  12  is passed through a coater  18  where a coating of hot, melted asphalt  19  is applied to the shingle mat  12  to form an asphalt-coated sheet  20 . The asphalt coating  19  may be applied in any suitable manner. In the illustrated embodiment, the shingle mat  12  contacts a roller  17 , which is in contact with the supply of hot, melted asphalt  19 . The roller  17  completely covers the shingle mat  12  with a tacky coating of asphalt  19 . However, in other embodiments, the asphalt coating  19  could be sprayed on, rolled on, or applied to the shingle mat  12  by other means. Typically the asphalt coating is highly filled with a ground mineral filler material, amounting to at least about 42 percent by weight of the asphalt/filler combination. In one embodiment, the asphalt coating  19  is in a range from about 350° F. to about 400° F. In another embodiment, the asphalt coating  19  may be more than 400° F. or less than 350° F. The shingle mat  12  exits the coater  18  as an asphalt-coated sheet  20 . The asphalt coating  19  on the asphalt-coated sheet  20  remains hot. 
         [0028]    The asphalt-coated sheet  20  is passed beneath a first granule applicator. In the illustrated embodiment, the first granule applicator is a blend drop applicator, shown schematically at  22 . The blend droop applicator  22  applies prime or blend drop granules  21  to the overlay prime granule lanes or lane portions of the asphalt-coated sheet  20 , such as the lanes PO 1  and PO 2  described below, to define blend drops  34 . Prime granules may also be applied to the underlay prime granule lanes, such as the lanes PU 1  and PU 2  also described below. Although only one blend drop applicator  22  is shown, it will be understood that several blend drop applicators  22  may be used. Alternatively, the blend drop applicator  22  may be adapted to supply several streams of blend drops, or blend drops of different colors, shading, or size to the asphalt-coated sheet  20 , thereby defining a granule-coated sheet  28 . 
         [0029]    The granule-coated sheet  28  is then passed beneath a second granule applicator. In the illustrated embodiment, the second granule applicator is a tracking granule applicator, shown schematically at  24  and described in its various embodiments below. The tracking granule applicator  24  applies granules to the granule-coated sheet  28  to selectively increase the thickness of the granule coating at a selected portion of the granule-coated sheet  28 . 
         [0030]    The granule-coated sheet  28  is then passed beneath a third granule applicator. In the illustrated embodiment, the third granule applicator is a backfall granule applicator  26 , for applying additional granules, such as shadow granules to form a shadow strip, background granules, and/or headlap granules  35  onto the granule-coated sheet  28 . 
         [0031]    The background granules headlap granules are applied to the extent that the granule-coated sheet  28  becomes completely covered with granules. The granule-coated sheet  28  is then turned around a slate drum  30  on a pre-designated track to press the granules into the asphalt coating and to temporarily invert the granule-coated sheet  28 . Such inverting of the granule-coated sheet  28  causes any excess granules to drop off the granule-coated sheet  28  on the backside of the slate drum  30 . The excess granules are collected by a hopper  32  of the backfall granule applicator  26  and may be reused. 
         [0032]    If desired, release tape  31  may be applied to the backside of the headlap granule lanes H 1  and H 2  of the granule-coated sheet  28 . For example, as shown in  FIG. 1 , release tape  31  may be applied from an applicator or roll  33  as the granule-coated sheet  28  moves around the slate drum  30 . 
         [0033]    As shown in  FIG. 1 , the hopper  32  is positioned on the backside of the slate drum  30 . Sensors S may be provided adjacent the slate drum  30  either upstream, downstream, or both upstream and downstream of the slate drum  30  to detect undesirable lateral movement of the granule-coated sheet  28  as the granule-coated sheet  28  moves across the slate drum  30 . The sensors S may be any desired type of sensor, such as a photo eye, a laser, a line camera, or edge detector. Alternatively, any sensor that can monitor the longitudinal edges of the granule-coated sheet  28  relative to the outside edges of the slate drum  30  may be used. 
         [0034]    The granule-coated sheet  28  is then cooled, cut, and packaged in any suitable manner (not shown). The cooling cutting and packaging operations are well known in the art. 
         [0035]    In the manufacture of laminated shingles, it is important to maintain lateral alignment between the granules deposited by the granule applicators, such as the blend drop applicators  22  and the longitudinal edges of the granule-coated sheet  28 . It is also important to maintain lateral alignment between the applied tape, such as the release tape  31 , and the longitudinal edges of the granule-coated sheet  28 . Known methods of laterally aligning granules or tape, such as by laterally moving the granule or blend drop applicators  22  and/or the tape applicator  33 , requires multiple and independent sensors and/or tracking mechanisms. Alternatively, the slate drum  30  could be moved, such as by rotating in a horizontal plane to reposition the granule-coated sheet  28 . Additional rolls may also be required to return a misaligned granule-coated sheet  28  to a desired position. The additional equipment and the mechanism required to move the slate drum  30  would therefore be very complex. 
         [0036]    The embodiments of the tracking granule applicator  24  described below advantageously allow the relative lateral position of the granule-coated sheet  28  to be controlled by selectively adding additional granules to shift the lateral or cross-machine distribution of granules on the granule-coated sheet  28 . 
         [0037]    A portion of an exemplary granule-coated sheet  28  is shown in  FIG. 3  after application of the prime granules  21  and/or the blend drops  34 . As shown, the granule-coated sheet  28  has a first longitudinal side  28 A (the left side when viewing  FIG. 3 ) and a second longitudinal side  28 B (the right side when viewing  FIG. 3 ) and may be formed in an apparatus  10  for forming multiple shingles. For example, the granule-coated sheet  28  may be formed in an apparatus  10  for forming a plurality of shingles, such as two, three, or four shingles. The background granules may include granules of different colors and/or types, such as headlap granules and prime granules, as described in detail above. In the embodiment illustrated in  FIG. 3 , the granule-coated sheet  28  includes six different lanes. In the embodiment of the granule-coated sheet  28  illustrated in  FIG. 3 , two headlap granule lanes H 1  and H 2 , two overlay prime granule lanes PO 1  and PO 2 , and two underlay prime granule lanes PU 1  and PU 2 , are shown. In the embodiment of the granule-coated sheet  28  shown in  FIGS. 3 &amp; 4 , the lanes PU 1 , H 1 , and PO 1  define a first longitudinal half of the granule-coated sheet  28 , and the lanes PU 2 , H 2 , and PO 2  define a second longitudinal half of the granule-coated sheet  28   
         [0038]    Interface lines  36  extend in the machine direction  13  and define a boundary between two granule lanes having a different color and/or type of granule. In the illustrated embodiments, the interface lines  36  are defined between adjacent headlap granule lanes and prime granule lanes, such as between the headlap granule lane H 1  and the prime granule lane PO 1 . 
         [0039]    As shown schematically in  FIG. 2 , a first embodiment of the tracking granule applicator  24  may include a hopper  38 . The hopper  38  receives and temporarily stores granules, such as headlap granules  35  from a source of granules (not shown). Alternatively, granules  35  may be moved into the hopper  38  by other suitable means. For example, the granules  35  may be moved into the hopper  38  through a gravity-feed device, such as a chute or tube (not shown). The tracking granule applicator  24  may also include a mechanism for metering and delivering the granules  35 . In the illustrated embodiment, the mechanism for metering and delivering the granules  35  includes a movable gate  40  for selectively releasing granules  35  into a chute  44 . The chute  44  guides the granules  35  outwardly and downwardly from the hopper  38  to the asphalt-coated sheet  20 . 
         [0040]    The illustrated chute  44  has a substantially flat lower surface  44 A, and may include side walls  44 B. Alternatively, the chute  44  may have other shapes, such as a substantially curved cross-sectional shape. The chute  44  extends outwardly and down-stream toward the upwardly facing surface of the asphalt-coated sheet  20 . 
         [0041]    It will be understood that the tracking granule applicator  24  described above is not required, and that any other desired granule dispenser may be provided. Examples of other suitable granule dispensers include a hopper having a fluted roll, and a vibratory feeder. 
         [0042]    Referring now to  FIGS. 4 ,  5 , and  6 , a second embodiment of a tracking granule applicator is illustrated at  50 . The tracking granule applicator  50  extends transversely across the granule-coated sheet  28  and defines an axis A. The tracking granule applicator  50  further includes a hopper  52 . The hopper  52  is structured and configured to include compartments (not shown) which separate the headlap granules from the prime granules. The desired headlap and prime granules (in the embodiment illustrated in  FIG. 5 , headlap granules  35  are shown) are fed from the hopper  52  by a fluted roll  54  from which, upon rotation, the granules  35  are discharged into contact with a chute  56 . A gate  58  is slidably mounted to the hopper  52  and movable in the direction of the arrow  60  for selectively releasing granules  35  into the chute  56 . 
         [0043]    If desired, the gate  58  may also be pivotally mounted relative to the hopper  52  about a pivot point P. Actuators or linkages  66  are connected to the gate  58  and move the gate  58  about the pivot point P, as will be described in detail below. The chute  56  guides the granules  35  outwardly and downwardly from the hopper  52  to the granule-coated sheet  28 . As shown in  FIG. 4 , the gate  58  is in a first or normal operating position. In the first position, the first and second ends  58 A and  58 B of the gate  58  are substantially equidistant from the fluted roll  54 . 
         [0044]    The illustrated chute  56  is elongated and has a substantially curved cross-sectional shape. Alternatively, the chute  56  may have any other desired cross-sectional shape. The chute  56  guides the granules  35  forwardly, in the direction of the arrow  13  as the granules  35  move downwardly away from the hopper  52 . As granules  35  exit the chute  56 , the granules  35  define a substantially linear curtain of the granules  62  which engage the asphalt-coated sheet  20  within a desired lane, such as the lane H 1  or H 2 , as best shown in  FIG. 4 . The fluted roll  54  may be driven by a drive motor (not shown). 
         [0045]    The chute  56  directs the granules  35  onto the asphalt-coated sheet  20 , such that the headlap granules are deposited into the headlap granule lanes H 1  and H 2 , and the prime granules are deposited into the prime granule lanes PU 1 , PU 2 , PO 1 , and PO 2 . If desired, the chute  56  may be provided with side walls (not shown) to maintain separation of headlap and prime granules, such that the headlap granules  35  and prime granules  21  are deposited in their respective granule lanes H 1 , H 2 , and PU 1 , PU 2 , PO 1 , and PO 2 , relative to the granule-coated sheet  28 . The chute  56  may be mounted to the apparatus  10  by any desired means, such as a mounting bracket  64 . 
         [0046]    In operation, the granule-coated sheet  28  may be manufactured as described above. When a sensor S detects undesirable lateral movement of the granule-coated sheet  28  as it moves across the slate drum  30 , additional headlap granules  35  may be deposited on the headlap granule lanes H 1  or the headlap granule lane H 2 . For example, if a sensor S determines that the granule-coated sheet  28  has moved laterally in a first direction (in the direction of the arrow D 1  when viewing  FIG. 3 ) relative to the slate drum  30 , additional headlap granules  35  are deposited in the headlap granule lane H 1 . The granule-coated sheet  28  will therefore be slightly thicker in the headlap granule lane H 1 . As the granule-coated sheet  28  with the increased granule thickness in headlap granule lane H 1 , moves around the slate drum  30 , the granule-coated sheet  28  will move, relative to the slate drum  30 , toward the headlap granule lane H 1  (in the direction of the arrow D 2  when viewing  FIG. 3 ). 
         [0047]    The additional headlap granules  35  deposited in the headlap granule lane H 1  may have a width W. In the illustrated embodiments, the width W of the additional headlap granules  35  is defined as any desired distance up to a maximum lateral distance that the additional headlap granules  35  may extend without contaminating, or being deposited within, the granule regions that will be exposed on a roof; i.e., the prime granule lanes PU 1 , PU 2 , PO 1 , and/or PO 2 . 
         [0048]    The additional headlap granules  35  deposited in the headlap granule lane H 1  may also have any desired thickness above a typical or pre-determined thickness of the granules retained on the granule-coated sheet  28  after the granule-coated sheet  28  has been turned around the slate drum  30  to press the granules into the asphalt coating. It will be understood that the additional headlap granules  35  deposited in the headlap granule lane H 1  will fall off the upwardly facing surface of the granule-coated sheet  28  and into the hopper  32  after the granule-coated sheet  28  has been turned around the slate drum  30 . 
         [0049]    Referring again to  FIGS. 2 and 3 , the additional headlap granules  35  are deposited in the desired headlap granule lane H 1  or H 2  by the first embodiment of the tracking granule applicator  24  mounted above the lane H 1  or H 2  to which additional headlap granules  35  will be deposited. 
         [0050]    For example, when a sensor S detects undesirable lateral movement of the granule-coated sheet  28  across the slate drum  30  in the direction of the arrow D 1 , additional granules may be deposited on the headlap granule lane H 1  from the tracking granule applicator  24  mounted above the lane H 1 . When the granule-coated sheet  28  has returned to its desired lateral position relative to the slate drum  30 , the tracking granule applicator  24  will close such that additional headlap granules  35  are no longer deposited in the headlap granule lane H 1 . Alternatively, at least some additional granules may be substantially continuously deposited onto the granule-coated sheet  28  by either the tracking granule applicator  24  mounted above the lane H 1  or the tracking granule applicator  24  mounted above the lane H 2  to maintain the granule-coated sheet  28  in a desired lateral position relative to the slate drum  30 . 
         [0051]    Referring again to  FIGS. 4 ,  5 , and  6 , additional prime granules  21  and/or headlap granules  35  may deposited in the desired headlap granule lane H 1  or H 2 , or underlay prime granule lanes PU 1  or PU 2 , respectively, by the second embodiment of the tracking granule applicator  50 . 
         [0052]    For example, when a sensor S detects undesirable lateral movement of the granule-coated sheet  28  across the slate drum  30  in the direction of the arrow D 1 , additional granules may be deposited on one or both of the underlay prime granule lane PU 1  or the headlap granule lane H 1 . The granule-coated sheet  28  will therefore be slightly thicker in one or both of the underlay prime granule lane PU 1  and the headlap granule lane H 1 . The linkages  66  urge a selected portion of the gate  58  away from the fluted roll  54  such that one end of the gate  58  creates a slightly larger opening  68  between the gate  58  and the fluted roll  54 . In the illustrated embodiment, a first end  58 A of the gate  58  is moved away from the fluted roll  54  to create a slightly larger opening  68  between the first end  58 A of the gate  58  and the fluted roll  54 . 
         [0053]    In another embodiment, the gate  58  may be pivoted slightly in the direction of the arrow CW (in a clockwise direction when viewing  FIG. 6 ) about the pivot point P, as shown by the phantom line  58 ′ in  FIG. 6 . The linkages  66  urge the gate  58  such that the gate  58  is pivoted slightly in the direction of the arrow CW (in a clockwise direction when viewing  FIG. 6 ) about the pivot point P, as shown by the phantom line  58 ′ in  FIG. 6 . 
         [0054]    Such clockwise pivoting movement of the gate  58  creates a slightly larger opening  68  between a first end  58 A of the gate  58  and the fluted roll  54 . The opening  68  defines a flow path for granules at the first end  58 A of the gate  58  within the hopper  52 . One or both of additional prime granules  21  or headlap granules  35  are then deposited in the underlay prime granule lane PU 1  or the headlap granule lane H 1 , respectively. The granule-coated sheet  28  will therefore be slightly thicker in one or both of the underlay prime granule lane PU 1  and the headlap granule lane H 1 . 
         [0055]    When the granule-coated sheet  28  has returned to its desired lateral position relative to the slate drum  30 , the linkages  66  will urge the gate  58  slightly such that the gate  58  is pivoted in a counter-clockwise direction about the pivot point P, and back to the first position wherein the first and second ends  58 A and  58 B of the gate  58  are substantially equidistant from the fluted roll  54 . 
         [0056]    It will be understood that the tracking granule applicator  50  described above is not required, and that any other desired granule dispenser having a slidable and/or pivotable gate may be provided. 
         [0057]    The present invention should not be considered limited to the specific examples described herein, but rather should be understood to cover all aspects of the invention. Various modifications, equivalent processes, as well as numerous structures and devices to which the present invention may be applicable will be readily apparent to those of skill in the art. Those skilled in the art will understand that various changes may be made without departing from the scope of the invention, which is not to be considered limited to what is described in the specification.

Technology Classification (CPC): 1