Abstract:
A uniformly applied monolithic roofing surface membrane at appropriate thickness and pitch is field applied upon a surface. The surface membrane may be field applied from a spray applicator foam dispenser moving between two parallel tracks. The uniform application of foam at each pass is assured, by accelerating the speed of the foam dispenser at the end of each pass, by providing continuous movement of the spray applicator upon the tracks. The monolithic roofing surface monolithic thus formed includes a spontaneously curable polymer, such as low rise polyurethane adhesive or polyurethane foam, having a mesh such as of fabric or fiberglass therein, with a silicone coating thereon.

Description:
[0001]    This application is a continuation-in-part of application Ser. No. 08/970,196, filed Nov. 14, 1997, which application is based in part upon Disclosure Document No. 373320 dated Mar. 8, 1995 and Provisional Patent Application, Serial No. 60/030,914, filed on Nov. 14, 1996. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to monolithic in situ field-applied roofing surface membranes. Preferably, the surface membrane is a fabric or fiberglass imbedded low rise polyurethane adhesive covered by a waterproof and ultraviolet resistant coating, such as a silicone coating.  
           [0003]    The present invention also relates to a new and useful method and industrial robotic device for applying coatings or other spray coated layers, in uniform thicknesses and at appropriate angles of pitch, in field applications, such as roofing applications or pavement applications.  
         BACKGROUND OF THE INVENTION  
         [0004]    In the roofing applications, flat roofs are often made of polyurethane foam layers, which may be covered by various coatings, such as elastomeric coatings, such as silicone. It is difficult to maintain a uniform thickness when applying a foam or elastomeric material, which by its nature rises when applied to achieve a thickness above a roof base.  
           [0005]    Furthermore, the faster that a foam applicator passes over a surface, the less volume of foam is applied, resulting in less of a thickness of the applied foam. To achieve thicker foam layers, a spray applicator is slowed down in velocity as it passes over the roof bases, so that more foam material is discharged per square unit of space of roof base being passed over by the spray applicator.  
           [0006]    Various attempts have been made to apply foam uniformly, such as from an applicator moving at a uniform speed along a carriage track. However, at the end of each pass of an applicator over a portion of a roof base, the discharged foam is applied twice, i.e. once at the end of the pass to the edge, and again as it starts over above the previously applied foam, until the carriage can adjust to an unsprayed area.  
           [0007]    Field applied roofing foam surface membranes are rigid polyurethane foam surface membranes, such as manufactured by Stepan Company of Pennsylvania under the trade name STEPANFOAM®.  
           [0008]    Stepan Company also manufactures a roofing product known as “low rise polyurethane adhesive”, brand name number RS 9514B, which is a concentrated polyurethane foam type adhesive often used to adhere solid rubber roof substrates to flat roof substrate structures.  
           [0009]    However, it has not been known to imbed a low rise polyurethane adhesive with a woven polyester fabric or fiberglass layer and coat the formed substrate with silicone to create a monolithic integral roofing surface membrane for flat roofs, without the need for attaching a prefabricated roofing sheet, such as of vulcanized rubber, to the underlying roof substrate.  
           [0010]    Furthermore, Dow Corning Corporation of Midland, Michigan manufactures silicone-based roofing coatings for weatherproofing reasons and for resisting the effects of ultraviolet light, such as the POLYCOAT® R-4000 silicone roof coating. Other prior art coatings are described in U.S. Pat. No. 3,607,972 of Kiles, et al, assigned to Dow Corning corporation, such as a room temperature vulcanizable siloxane-based block copolymer.  
           [0011]    U.S. Pat. No. 5,253,461 of Janoski, assigned to Tremco, Inc. describes a cold-process built-up roofing system, which includes a curing adhesive with tarpaper and asphalt. The adhesive in its uncured state is substantially flowable, comprising asphalt and a compatibilizer and optionally a filler, dispersed in a curable polyisocyanate prepolymer. However, in Janoski &#39;461 the adhesive takes up to 10 hours to cure, unlike spontaneously cured polyurethane-based foams.  
           [0012]    Among prior art devices for applying coatings include U.S. Pat. No. 5,381,597 of Petrove which describes a wheeled robotic device for installing shingles on roofs. While it does not concern spraying of urethane foam upon a flat roof, it does describe a movable, wheeled carriage for use upon a roof.  
           [0013]    U.S. Pat. No. 5,620,554 of Venable, assigned to Carlisle Corporation of Syracuse, N.Y. describes an apparatus for making a composite roofing material, including a reel support for reels of prefabricated vulcanized rubber sheets, a polymeric film and fleece matting, wherein rollers advance the solid rubber sheet from its reel, which heat and stretch the rubber, binding it to the polymeric film and fleece matting.  
           [0014]    However, in Venable &#39;554, there must first be a reel of a prefabricated solid rubber sheet, not an spontaneously formed monolithic roofing surface membrane.  
           [0015]    Moreover, U.S. Pat. No. 5,872,203 of Wen describes a polyurethane adhesive for bonding polymeric roofing sheets to flat roof decks, which includes a two-component curable mixture, such as a polyurethane prepolymer and a polyol.  
           [0016]    In addition, British patent application GB 2,055,326A of CCG Roofing Contractors, Limited describes a prefabricated polymer board that includes two layers with a fabric mesh therein. However, the fabric mesh is mechanically imbedded between the two layers during fabrication forming, and does not describe imbedding a fabric spontaneously within a polyurethane foam as the spray-applied foam rises up and through the fabric.  
           [0017]    U.S. Pat. No. 5,248,341 of Berry concerns the use of curved walls to accommodate spray paint applicators for curved surfaces, such as aircraft.  
           [0018]    U.S. Pat. No. 5,141,363 of Stephens describes a mobile train which rides on parallel tracks for spraying the inside of a tunnel.  
           [0019]    U.S. Pat. No. 5,098,024 of MacIntyre discloses a spray and effector which uses pivoting members to move an armature which holds a spray apparatus.  
           [0020]    U.S. Pat. No. 4,983,426 of Jordan discloses a method for the application of an aqueous coating upon a flat roof by applying a tiecoat to a mastic coat.  
           [0021]    U.S. Pat. No. 4,838,492 of Berry discloses a spray gun reciprocating device, wherein parallel tracks are used wherein each track is square in cross section, but further wherein each track guides a plurality of rollers thereon.  
           [0022]    U.S. Pat. No. 4,630,567 of Bambousek discloses a spray system for automobile bodies, including a paint booth, a paint robot apparatus movable therein, and a rail mechanism for supporting the apparatus thereat.  
           [0023]    U.S. Pat. No. 4,567,230 of Meyer describes a chemical composition for the application of a foam upon a flat roof.  
           [0024]    U.S. Pat. No. 4,167,151 of Muraoka discloses a spray applicator wherein a discharge nozzle is moved transversally upon a frame placed adjacent and parallel to the surface having the foam being applied thereto. However, the applicator of Muraoka &#39;151 does not solve the problem of excess foam being applied at the end of each transverse pass of the discharge nozzle.  
           [0025]    U.S. Pat. No. 4,209,557 of Edwards describes a movable carriage for a nozzle applying adhesive to the back of a movably advancing sheet of carpeting. Similarly, Australian Patent no. 294,996 of Keith describes a movable carriage for a nozzle applying a polyurethane foam coating to a movably advancing sheet.  
           [0026]    U.S. Pat. No. 4,016,323 of Volovsek also discloses the application of foam to a flat roof.  
           [0027]    U.S. Pat. No. 3,786,965 and Canadian Patent no. 981,082, both of James, et al, describe a self-contained trailer for environmentally containing a dispenser for uniformly dispensing urethane foam upon a terrestrial surface, wherein the problem of “skewing” occurs at the completion of each pass at the boundary edges of the surface to which are urethane foam is being applied. James &#39;965 employs self-enclosed gantry robots to move the fluid discharge nozzle over the terrestrial surface.  
           [0028]    U.S. Pat. No. 3,667,687 of Rivking discloses a foam applicator device.  
           [0029]    U.S. Pat. No. 1,835,402 of Juers describes an apparatus for spraying glass from a nozzle transversely along a flat surface and U.S. Pat. No. 3,027,045 of Paasche discusses a coating machine where the nozzle moves by a pivot arm.  
           [0030]    U.S. Pat. No. 3,096,225 of Carr discloses a hand-held spray nozzle for depositing a continuous stranded material, such as glass.  
           [0031]    U.S. Pat. No. 2,176,891 of Crom discloses an apparatus for applying coatings over curved surfaces, such as within ditches or other curved surfaces. Moreover, U.S. Pat. No. 4,210,098 of Harrison also discloses an apparatus for spraying insulation or other coatings upon curved surfaces.  
           [0032]    Other related art includes U.S. Pat. No. 2,770,216 of Schook for a pivotable spray nozzle, U.S. Pat. No. 3,548,453 of Garis for a transverse spray apparatus, U.S. Pat. No. 3,705,821 of Breer for a transverse spray apparatus, U.S. Pat. No. 3,867,494 of Rood, et al, also for a transverse spray apparatus, U.S. Pat. No. 3,885,066 of Schwenniger for a spray apparatus with a plurality of nozzles and U.S. Pat. No. 3,923,937 of Piccoli, et al, for a centrifugally moving spray nozzle.  
           [0033]    U.S. Pat. No. 3,954,544 of Hooker describes a method of applying a membrane covered rigid foam and a method of bonding a sheet or web, and U.S. Pat. No. 4,659,018 of Shulman discloses an orbiting nozzle apparatus.  
           [0034]    U.S. Pat. No. 4,474,135 of Bellafiore discloses an apparatus for spraying a coating upon a spherical object supported by a post, which apparatus includes a curved track for providing orbital movement of a spray applicator about the exterior spherical surface of the sphere to be coated. While they are curved in nature, the curved tracks thereof are provided for orbital movement about the sphere, not to change the speed, tilt and direction of a linearly moving nozzle.  
           [0035]    Another attempt to solve the problem of “double spraying” at a pass edge has been described in U.S. Pat. No. 4,333,973 of Bellafiore, which describes a similar spray applicator, such as that of Autofoam® Company. This spray applicator includes a wheeled, self-movable vehicle having a carriage portion with a horizontal linear track thereon. The spray applicator moves from one end of the track to the other, opposite end of the track at the end of one pass, of the applicator, above a portion of a roof base, and then the applicator reverses direction upon the track.  
           [0036]    However, to avoid the “double spraying” problem noted above, the Autofoam® device has an on-off switch which turns the applicator off at an appropriate time at the end of a pass while the applicator is reversing direction, and re-starts the applicator a short time later when the applicator has started to move in the opposite direction.  
           [0037]    Moreover, there are severe problems with this approach, as the constant “on-off” starting and re-starting of the applicator causes fatigue to the metal or other material parts of the applicator, and a detrimental effect to the end product. In addition, the Bellafiore &#39;973 and Autofoam® devices are bulky and complicated to use.  
           [0038]    In addition, while monolithic field applied, spontaneously sprayed polyurethane foam roofing surface membranes are convenient, they use up considerable amount of material in creating the roofing surface membrane.  
         OBJECTS OF THE INVENTION  
         [0039]    Therefore, the objects of the present invention are as follows:  
           [0040]    It is an object of the present invention to provide a monolithic, unitary integral roofing surface membrane from a combination of a low rise polyurethane adhesive, a reinforcing mesh and a weather proofing and ultraviolet resistant coating.  
           [0041]    It is also an object of the present invention to provide a thin monolithic reinforced roofing surface membrane which cures spontaneously.  
           [0042]    It is also an object of the present invention to provide a thin but durable reinforced roofing surface membrane for roofs.  
           [0043]    It is yet another object of the present invention to provide a method of applying a fabric or fiberglass mesh within an spontaneously curved polymer roofing surface membrane while the polymer is being spontaneously cured at a roofing field application.  
           [0044]    It is further an object of the present invention to provide a method and apparatus for providing monolithic fabric and/or fiberglass reinforced roofing surface membranes.  
           [0045]    It is another object of the present invention to provide a spray applicator for foam roofing which applies a coating of elastomeric foam of uniform thickness.  
           [0046]    It is also an object of the present invention to provide a single yet efficient spray applicator for foam roofing.  
           [0047]    It is also an object of the present invention to provide a spray applicator that can be disassembled into a few major parts for easy transport and reassembly on a roof without resorting to the use of a crane.  
           [0048]    It is yet another object of this invention to provide a method for covering a large area of a roof with foam roofing using a continuous spray.  
           [0049]    It is also an object of the present invention to provide a spray applicator with a nutating nozzle mount to minimize variations in coating thickness.  
           [0050]    It is a further object of the present invention to provide a hand-held remote control to enable the spray applicator vehicle to operate without an on-board operator.  
           [0051]    It is an object of the present invention to provide a method for continuous adhesive spraying and application of elastomeric sheet roofing material of large strip areas of a roof.  
           [0052]    It is a further object of the present invention to provide accessories for the spray applicator vehicle to permit its use for applying elastomeric sheet roofing material from a roll.  
           [0053]    It is also an object of the present invention to improve over the disadvantages of the prior art.  
         SUMMARY OF THE INVENTION  
         [0054]    In keeping with these objects and others which may become apparent, and to solve the problems inherent in the Bellafiore &#39;973 and Autofoam® spraying devices, the present invention uses one or more track rails, such as a double linear track of round cross section, as shown in the drawings herein, to continuously apply monolithic polyurethane roofing surface membranes.  
           [0055]    In one embodiment, there is an arcuate uphill end portion of the track at each side, so that the spray applicator, which moves along the one or more linear tracks, will accelerate in speed and tilt the discharge nozzle outward as it rolls up the curved uphill portion, thereby reducing the amount of foam applied to the edge portion of the roof at the end of a pass of the applicator.  
           [0056]    To obviate the complicated mechanisms of the Autofoam® device, the present invention uses simple mechanics to move the spray applicator. For example, a transverse linear movement means, such as, a radially extending swinging arm, is provided for the sideways movement of the applicator along the track. To eliminate arcuate movement of the pivoting arm, the transverse linear movement means may have a telescoping mechanism or other gear assembly, so that the spray applicator moves linearly, instead of arcuately. For example, the swinging arm moves about a pivot fulcrum point.  
           [0057]    Other transverse movement mechanisms may be used, such as rack and pinion devices.  
           [0058]    To further insure uniform thickness, the present invention further comprises various speed controls, so that an appropriate thickness can be applied for each pass.  
           [0059]    For example, a rheostat controls the speed of the movement of the spray applicator, and an LED readout tachometer has a display dial with appropriate readings for appropriate speeds for corresponding desired thicknesses. Since the rate of flow of foam-producing material emanating from the nozzle is fixed, the ground movement speed of the applicator determines the weight of the coating per unit area applied. This, in turn, determines the thickness.  
           [0060]    When a slope is desired on a flat roof, such as toward a drainage line, the ground speed of the foam applicator can be reduced on each successive pass away and parallel to the drainage line. This will result in a stepwise slope approximating the desired contour.  
           [0061]    It has been found that a nutating nozzle holder, which tilts the nozzle a small amount cyclically as it traverses the track, can be used to minimize the variations in foam thickness (in the form of rounded ridges) due to the hollowcone pattern of the nozzle.  
           [0062]    Accessories can be added to the spray applicator so that it can be adapted for spraying adhesive on a roof or for automatically laying an elastomeric sheet covering such as Sure-Seal™ Fleece Back 100 EPDM made by Carlisle SynTec Incorporated of Carlisle, Pa. over a polyurethane foam substrate. Accessories can also be added for imbedding reinforced fabric within the polyurethane foam substrate.  
           [0063]    In one embodiment, the primary roofing surface membrane is a polyurethane foam, such as STEPANFOAM® of Stepan Corporation. In this embodiment, the average thickness of the deposited foam is about two inches in thickness.  
           [0064]    However, in the preferred embodiment, instead of a standard polyurethane foam roof surface membrane of about 2 inches in thickness, the preferred monolithic roof surface membrane is much thinner, rising to a thickness of about one quarter (¼) inch in thickness.  
           [0065]    This is because, instead of using standard polyurethane foam such as STEPANFOAM®, what is used is what is known in the trade industry as a “low rise polyurethane adhesive”, such as brand name number RS9514B, also manufactured by Stepan Corporation.  
           [0066]    Previously, low rise polyurethane adhesives have only been used to act as an adhesive to adhere prefabricated roofing, such as vulcanized rubber sheets, to roof deck surfaces.  
           [0067]    These low rise polyurethane adhesives have not previously been used as a component of a monolithic roofing surface membrane itself.  
           [0068]    The combination of low rise polyurethane adhesive with a reinforcing mesh and a silicone-based coating obviates the need for a thick polyurethane foam base of about two inches.  
           [0069]    Therefore, the present invention includes a field applied, monolithic roofing surface membrane, which includes a combination of a low rise polyurethane adhesive with a fabric or fiberglass mesh adding reinforcement thereto, such as a woven polyester, i.e., what is known as a 6 or 10 ounce fabric mesh.  
           [0070]    The mesh is applied to the low rise polyurethane adhesive from a rolling reel and is embedded within the polyurethane adhesive by virtue of the rising, spontaneously cured polyurethane adhesive contacting and rising through the recess spaces between the fabric or mesh structural fibers, thus encasing the mesh within the polyurethane adhesive during the curing of the polyurethane adhesive.  
           [0071]    In the preferred embodiment of the present invention, a subsequent application of a silicone-based coating is applied also by spray nozzle over the already-deposited and mesh reinforced low rise polyurethane adhesive surface membrane.  
           [0072]    This silicone coating adds a seal for weather proofing the underlying mesh reinforced polyurethane adhesive layer and for resisting damage from ultraviolet light. A typical silicone coating is POLYCOAT 4000 of Dow Corning Corporation, or as described in U.S. Pat. No. 3,607,972 of Kiles, et al, assigned to Dow Corning Corporation.  
           [0073]    When the silicone coating is applied, it has a thickness of about 20 mils. The thickness of the reinforcing mesh layer and the silicone coating together is about 30-100 mils. The total thickness of the preferred monolithic roofing surface membrane, including the silicone coating and the mesh-reinforced polyurethane adhesive, is about one quarter (¼) inch in thickness, which is significantly thinner than the two (2) inch thickness of a spray applied foam roofing substrate.  
           [0074]    While the invention has been described for use in applying roofing materials on roofs, it is also usable for spray applications at ground level such as for pavement painting or sealing applications.  
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0075]    The present invention can best be described in conjunction with the accompanying drawings, in which:  
         [0076]    [0076]FIG. 1 is a top plan view of a spray applicator vehicle of the present invention;  
         [0077]    [0077]FIG. 2 is a side elevation of a spray applicator vehicle of the present invention;  
         [0078]    [0078]FIG. 3 is a side cross section detail of a transverse rail and carriage;  
         [0079]    [0079]FIG. 4 is an end elevation of a transverse rail and carriage;  
         [0080]    [0080]FIG. 5 is a block diagram of a spray applicator electrical system;  
         [0081]    [0081]FIG. 6 is an end cross section of a coated roof with a central drain ridge;  
         [0082]    [0082]FIG. 7 is a block diagram of a spray applicator electrical system using a hand-held remote control;  
         [0083]    [0083]FIG. 8 is a nozzle spray pattern and resultant foam cross section;  
         [0084]    [0084]FIG. 9 is a nutating spray nozzle feature with details thereof; wherein FIG. 9A is a side elevation of a nozzle holder and an actuator cable; and, FIG. 9B is a top plan view of a cam and cam follower;  
         [0085]    [0085]FIG. 10 is a side elevation of a spray applicator as adapted for laying elastomeric sheet roofing material; and, FIG. 11 is a side elevation of a spray application vehicle as adapted for applying fabric or mesh reinforced foam coating.  
         [0086]    [0086]FIG. 12 is a cross-sectional view of a monolithic field-applied, mesh-reinforced polyurethane foam roofing surface membrane of the present invention; and  
         [0087]    [0087]FIG. 13 is a cross-sectional view of a monolithic field-applied, mesh-reinforced low rise polyurethane adhesive and silicone-coated roofing surface membrane of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0088]    As shown in FIGS.  1 - 2 , spray applicator  1  is used for applying polyurethane foam coatings or other spray coated layers, such as low rise polyurethane adhesives, in uniform thicknesses in field applications, such as roofing applications or pavement applications.  
         [0089]    As shown in FIGS. 1 and 2, spray applicator vehicle  1  includes frame  2 , operator seat  5 , steerable powered single wheel  50 , two unpowered side wheels  4 , swinging boom  18 , transverse rail subassembly  23  and various associated parts of nozzle  62  attached to carriage plate  26 . Motor  6  drives sprocket  52  of chain  8  through gear reduction box  7  to provide vehicle motion via wheel sprocket  51 . The operator steers the vehicle  1  by steering wheel  9 , which moves steering linkage bar  57 , thereby rotating wheel flange  58 . Boom  18  is continuously reciprocated from pivot point  20  on tower  55  by crank arm  16  which is cyclically moved by reduction gear box  13  powered by motor  12 , via adjustable linkage arm  14 . Linkage arm  14  is attached to output shaft  17  and is rotated at a constant speed as determined by settings in control box  11 . Slot  15  permits adjustment of the lateral movement limits of telescoping end  19  of boom  18 . Rails  24  and  25  constrain the movement of carriage plate  26  to a linear path transverse to frame  2 . Other transverse movement means may be used, such as rack and pinion gear assemblies.  
         [0090]    Control box  11  also sets the ground speed of vehicle  1 . Hose  35 , which may consist of two or more separate hoses or individual lumens, carries liquid materials, such as polyurethane foam or low rise polyurethane adhesive, for spraying through nozzle  62  from a remote pressurized source.  
         [0091]    For polyurethane foam, or low rise polyurethane adhesive, two chemicals supplied from separate hoses  35  are mixed at the nozzle  62  just prior to discharge. The two liquids interact chemically causing an exothermic foaming and hardening reaction.  
         [0092]    Hose  35  is retained in boom bracket  37  and may also be attached in one or more places by hook and loop straps  36 . In normal use, a second (non-riding) work person guides hose  35 . Solenoid  38 , actuated by a switch in control unit  11 , operates the discharge valve at nozzle  62 .  
         [0093]    It can be appreciated that vehicle  1  rolling at a constant speed with transverse movement means, such as boom  18 , reciprocating continuously, is able to spray a continuous strip of coating on a surface. If the discharge rate at the nozzle is held constant, the amount of product sprayed on a surface per unit of sprayed area can be set by selecting ground speed.  
         [0094]    Since the transverse movement means, such as a boom or other assembly, changes direction at the distal ends of its swings, a method is employed to limit the amount discharged to prevent “double coating” at the edges.  
         [0095]    As noted before, prior art systems, such as described in Bellafoire &#39;973 and of Autofoam® Company, shut the nozzle off at these portions of the cycle. However this action causes several problems.  
         [0096]    For example, the on/off cycling has detrimental effects on spray material consistency from a chemical reaction point of view. The on/off cycling also causes mechanical wear and induces metal fatigue on brackets that must react to cyclic pressure loading.  
         [0097]    In contrast to the devices of Bellafoire &#39;973 and of the Autofoam® Company, the present invention uses a geometric arrangement and constant and continuous liquid product flow to prevent pattern edge build-up.  
         [0098]    For example, FIG. 3 shows a cross section of rails  24  and  25  in the middle of the transverse sweep. carriage plate  26 , driven by end bushing  27  on telescoping extension  19 , is shown with brackets  65  and  66  attached. Brackets  65  secure top rollers  29  with concave “hourglass” contours. Similarly contoured bottom rollers  53  are secured by brackets  66 . Thus rollers  29  and  53  capture rails  24  and  25  constraining plate  26  to roll along these rails. Plate  26  also supports nozzle holder assembly  34  (not shown in this figure).  
         [0099]    [0099]FIG. 4 shows an end view of one embodiment of rail subassembly  23 . While rails may be flat, preferably both rails  24  and  25  are curved at their distal ends in a constant radius. Nozzle assembly  34  is shown in a flat vertical spray location at “A” and at an oblique spray location at the extreme limit of travel on the curved portion at “B”. Top rollers  29  and bottom rollers  53  are offset from each other to facilitate easy rolling without binding on the curved portions. If the transverse movement means, such as boom  18  or other gear assembly, is reciprocated at an essentially constant rate, the carriage assembly is accelerated at the ends of travel due to the greater distance traveled per unit time on the curved end contour as well as the change in direction. Furthermore, the angle of nozzle  62  is tilted outward at the end so that the coverage area “BB” is larger than that of “AA”. These end factors combine to reduce the thickness of the sprayed layer so that the “double layering” at the edge of each applied band of polyurethane foam or low rise polyurethane adhesive can be controlled to result in an edge thickness essentially the same as that of the center portion of a pass. This can be adjusted empirically based on the particular batch, temperature and other field conditions. The adjustment is the end limit position of nozzle  62  relative to the track end curve as determined by the adjustment of crank arm  16  in slot  15  of linkage arm  14 .  
         [0100]    Spray vehicle  1  is designed to be easily disassembled into four subassemblies for easy transport to the roof of a building on an elevator or by using a winch. Prior art systems require a crane. Booms  18  and  19  can be lifted off as a unit by removing spring pin  22  from upright link  54 , spring pin  21  from pivot shaft  20  and spring pin  28  from carriage plate  26  coupling.  
         [0101]    A front subassembly including of track subassembly  23  with uprights  3  can be removed by removing two spring pins  30  from frame member  2 .  
         [0102]    Central frame  2  subassembly including wheels  4  can be separated from the driven wheel subassembly (including seat  5  and steering wheel  9 ) by removing large spring pin  60  from socket member  59  on the frame subassembly. Then back chassis  10  can be lifted free. Electrical connections tying the various subassemblies have connectors which must be disconnected. The four subassemblies can then be reassembled on the rooftop.  
         [0103]    [0103]FIG. 5 shows a block diagram of the electrical system largely housed in control box  11 . The spray applicator vehicle  1  is electrically operated by connection to standard AC mains (typically 115 VAC at 60 HZ) via plug  40  and extension cord  39 . A portable engine operated generator can supply this power as an alternative. Although two separate modular AC/DC converters  76  and  83  are depicted, a single converter can supply current to all DC loads.  
         [0104]    An AC power switch  75  controls power to the entire spray applicator vehicle  1 . Converter  76  supplies DC to a unidirectional speed control  77  with digital speed indicator  78  and speed set control  79 . For maximum consistency of application, speed control  77  is preferable a PID type of feedback servo control which maintains output speed of motor  12  (for moving the transverse movement means, such as via the swinging of boom  18  or otherwise,) constant via feedback from encoder  80  mounted on motor  12 .  
         [0105]    Switch  81  controls power to a solenoid  82  which opens the discharge valve at nozzle  62 . Converter  83  supplies DC power to a bidirectional PID speed control  84  with digital speed indicator  85  and speed set control  86 . This control accurately and repeatedly maintains the ground speed in either direction of spray applicator vehicle  1  as set even under varying load conditions by virtue of feedback encoder  87  mounted on motor  6 .  
         [0106]    This operation is used during the spraying operation and determines the thickness of the resulting sprayed layer.  
         [0107]    Control switch  89  determines the direction of movement as forward or reverse.  
         [0108]    A second manual bidirectional speed control  90  is used to quickly select the desired ground speed via alternate manual control  91  when it is desired to maneuver spray applicator vehicle  1  prior or after a spray application.  
         [0109]    In this manner, the carefully selected “automatic” setting for spraying is not altered. Either automatic speed control  84  or manual speed control  90  is actively enabled at any one time via selector switch  88 .  
         [0110]    The repeatable application of a desired amount of coating per pass permits the type of roof foam or low rise polyurethane adhesive surfacing depicted in FIG. 6. This is an exaggerated cross section of the end of a roof  61  surface with a central drain  96  ditch with grate cover  95 . If the roof  61  had a flat pitch, it would be desirable to create a pitch toward the drainage ditch for more effective drainage. This can be approximated by a stepped foam or low rise polyurethane adhesive layer as shown, starting from lowest strip “A” and rising in thickness to strip “E” of the thickest cross section farthest from central drain  96 . These strips can be applied in a single pass or in multiple passes by spray applicator vehicle  1  where the ground speed for layer “A” is fastest and the speed is reduced for each successive layer “B”, “C”, “D” “E” and “F”.  
         [0111]    For safety reasons, federal OSHA occupational safety regulations stipulate that a powered vehicle cannot be ridden by a workperson within ten feet of the edge of a roof. Also, a workperson is required to guide hose  35  while the operator rides and guides spray applicator vehicle  1 . For these reasons, it would be desirable to operate spray applicator vehicle remotely. In this manner, a single workperson controls spray applicator vehicle  1  and guide hose  35 .  
         [0112]    [0112]FIG. 7 shows such a remote control configuration. Control box  11  is replaced by a hand-held remote control box  100  with a face plate and several vehicle mounted functional units. Since the operator is no longer physically on spray applicator vehicle  1 , electric steering ram  102  replaces the steering wheel. Electric steeling ram  102  is controlled by positional steering control  101 , which sets the position of steered wheel  50  to match that of steering control wheel  106  on remote control box  100 .  
         [0113]    Communications between remote control box  100  and spray applicator vehicle  1  is via coiled cable  105 , although a fail-safe radio communications channel can be used as well. To limit the number of individual conductors in cable  105 , a multiplexor/demultiplexor module  103  and  104  is used at each end of cable  105  to facilitate the two way communications. The function of similarly numbered components is the same as that explained above in reference to FIG. 5.  
         [0114]    Hollow-cone nozzle  62  sprays a pattern  110  of polyurethane foam or low rise polyurethane adhesive that impinges on the ground as shown in FIG. 8. As this pattern is swept sideways in a single pass, it will lay material that is denser toward the top and bottom edges resulting in a cross section with ridges  111  and valley  112  in the “Y” direction from roof surface  61 .  
         [0115]    While multiple sweeps by boom  18  mitigate this effect somewhat, ridges in the final sprayed surface still persist. This problem is eliminated by nutating or cyclically rocking the nozzle mount  34  slightly at right angles to rails  24  and  25  several times during each sweep to even out the coverage of hollow-cone nozzle  62  over multiple sweeps.  
         [0116]    [0116]FIG. 9 shows optional modifications to accomplish this. The detail of FIG. 9A shows modified bracket  120  with pivot  121  holding nozzle mount  34 . Bracket  120  is fastened to carriage plate  26 . A push-pull cable assembly including armored housing sleeve  123  with cable  122  within is used to actuate the cyclic motion illustrated by the phantom representation (shown in broken lines) of nozzle holder  34  at the extreme outward position. The detail of FIG. 9B shows the powering end of cable  122 . Bracket  126 , attached to the frame of vehicle spray applicator  1  in the vicinity of gear box  13 , retains sleeve  123 . Cam follower  130  is pivoted at pivot point  128  within adjustment slot  127  and is biased toward multiple lobe cam  131  by spring  129 . The stroke of wire  122  (and therefore the amount of cyclic tilt of nozzle holder  34 ) is determined by the dimensions and geometry of cam follower  130  and the depth of lobes on multiple lobe cam  131 .  
         [0117]    The proper centering of the motion of holder  34  is adjusted by moving pivot  128  within slot  127 . Multiple lobe cam  131  is attached to the output shaft of gear box  13  under arm  14 . It can be appreciated that cable wire  122  is cycled by each cam lobe as multiple lobe cam  131  rotates.  
         [0118]    By moving cam follower  130  out of contact with multiple lobe cam  131  and tightening it in a locked position, to defeat the pivoting, nozzle holder  34  can be locked in a vertical position to defeat the nutating feature.  
         [0119]    Alternatively, a separate small gear motor and crank coupling (not shown) mounted right on bracket  120  can be used to actuate the nutating action without need of cable  122 .  
         [0120]    Spray applicator vehicle  1  is easily modified to adhesively bond sheet elastomeric roofing material. As shown in FIG. 10, side arms  141  are pivoted at pivot point  140  from side extensions (not shown) which are attached to frame  2 . These arms  141  have telescoping extensions  142  which are locked with hand screws  143 . A roll of elastomeric sheet  144  is pivoted at the end of arms  142  at pivot point  148 , with sheet end  145  trailing roll  144  as vehicle spray applicator  1  moves in the direction of arrow  149 . Also pivoted at pivot point  148  are side arms  146  which trail a weighted roller  147 , which weighted roller  147  applies even pressure to sheet layer  145 . Nozzle  62  sprays a layer of bonding adhesive which bonds sheet  145  to roof surface  61 .  
         [0121]    Alternately, roll  144  can be adjusted to apply a skin coating of rolled material over the solidified foam layer applied from nozzle  62  to a surface, such as a roof.  
         [0122]    Adjustment of extensions  142  determine the distance X between the sheet contact and the sprayed roof surface a fixed distance from the center of the spray cone. Since the vehicle moves at a predetermined constant speed, distance X can be used to match the optimal delay from adhesive application to contact of the sheet roofing material.  
         [0123]    A method for applying reinforced foam or polyurethane adhesive roofing involves the use of a reinforcing fabric or open fabric mesh. The fabric can be manufactured of a variety of fibers such as nylon, fiberglass, aramid, etc. The method involves spraying a foaming mixture and immediately imbedding the reinforcing fabric in the mixture before the foam rises so that the reinforcing fabric rises with the foam and is embedded in the foam layer.  
         [0124]    [0124]FIG. 11 shows modifications of the spraying applicator vehicle  1  for accomplishing this task. Side arms  160  are rigidly attached to frame  2  and uprights  3 ; they flare out at the distal end to lie outside of the spray pattern on each side. Roll  164  of lightweight reinforcing fabric is pivotally attached at the end of arms  160 . The free end of fabric  165  is fed under light roller  162 , which contacts surface  61  just at the edge of the foam adhesive spray pattern. Spring plunger  161  supported by brace  163  forces roller  162  into contact with roof surface  61 . Foam spray  168 , prior to rising, is contacted with fabric  165 , which rises with foam  166  to embed itself in the foam layer as shown by the broken line.  
         [0125]    [0125]FIGS. 12 and 13 show cross sectional views of portions of roofing substrates provided in the present invention.  
         [0126]    For example, while a monolithic polyurethane foam-based roofing surface membrane is at least 1-2 inches in thickness to provide a strong base, the preferred roofing surface membrane including a mesh-reinforced low rise polyurethane adhesive under a silicone coating can have a thickness of only about one quarter (¼) inch. This saves considerably in the amount and cost of material deposited.  
         [0127]    In FIG. 12, polyurethane foam layer-based  168  is imbedded with mesh  165  and covered by silicone coating  175 . This provides a roofing surface membrane of about 1-2 inches in thickness.  
         [0128]    In contrast, as shown in FIG. 13, a preferred embodiment of a much thinner monolithic roofing surface membrane of from about one quarter (¼) inch in thickness is provided with a base layer  178  of low rise polyurethane adhesive having mesh layer  165  therein and coated by silicone coating  175  for weatherproofing and for resisting the effects of ultraviolet light. Therefore, a substantial savings of material and cost is achieved without compromising the structural and sealing characteristics of the monolithic roofing surface membrane.  
         [0129]    It is further noted that other modifications may be made to the present invention without departing from the scope as noted in the appended claims.