Abstract:
A box truck for supplying sufficient electrical power and compressed air flow to enable spray foam contractors to use specialized equipment to foam insulate buildings. Such a truck has the necessary generator and air compressor systems mounted within the chassis of the vehicle and said systems do not take up valuable cargo space within the truck box, while utilizing components present in normal box truck designs to assist in their operation. The generator system is hydraulically powered and utilizes a PTO (Power Take-Off) mechanism to use power from the truck power train to drive the hydraulic system. The air compressor is a screw type compression system and is belt driven off the truck engine.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to a motor vehicle configured for supplying sufficient electrical power and compressed air flow to enable spray foam contractors to use specialized equipment to foam insulate buildings. 
       BACKGROUND OF THE INVENTION 
       [0002]    Spray foam polyurethane has become a popular form of building insulation. One such system, SEALECTION 500 spray foam insulation sold by Demilec (USA) LLC, is a semi-rigid thermoset polyurethane foam composed of millions of microscopic cells of which most are open. 
         [0003]    The application of the product is done at the job site. To spray the foam to insulate a building according to existing practice, a truck containing the necessary special equipment is driven to the job site. Both a generator and an air compressor are needed. The foam spraying process components include a pair of tanks of reactants that are not mixed until the reactants reach the head of a spray gun at the job site, and a reactor mounted in the truck that controls reactant flow and temperature. An air drier is also mounted in the truck so that air from the air compressor that is used for spraying is as free of humidity as possible. Numerous pumps and heaters are needed, including specialized thermocouples built into the hoses that carry the reactants to the gun while maintaining the required elevated temperature. These components require electric power to operate. Compressed air is also supplied to the breathing system of the gun operator, who carries out the spraying process while wearing a sealed suit. 
         [0004]    Box trucks currently in use mount self-powered generator and air compressor units inside the box (truck body) in a room or compartment provided for that purpose, occupying 3 to 4 feet of the box in the lengthwise direction. The other components needed to carry out the foam spraying process must then be place in the remainder of the box, which needs to be larger for that purpose, or else carried on a trailer. There exists a need for a truck that does not require large portions of its box space to beg taken up by systems necessary for the application of spray foam polyurethane. This invention addresses that need by permitting the use of a smaller truck and box, since all the components are mounted on the outside of the box except for the control unit. This allows for a more compact installation with a larger generator and air compressor. 
       SUMMARY OF THE INVENTION 
       [0005]    A motor vehicle according to the invention is configured for carrying a spray foam insulation system that uses electrical power from a generator and compressed air. The vehicle includes a frame, a cab, a front engine compartment housing an engine which outputs rotary motion to a crankshaft, a drive shaft which propels wheels of the vehicle, a transmission which transmits rotary motion of the crankshaft to the drive shaft, and a rear body or box enclosure behind the cab configured for storing and carrying objects. An air compressor is mounted in the front engine compartment and connected by a belt and pulley to the crankshaft. A clutch and a first control system are provided for allowing the air compressor to be turned off and on while the engine is running. A power take off is connected to the transmission, including a secondary drive shaft and a second control system for engaging and disengaging the power take off. A closed-loop hydraulic pump is connected to and operated by the secondary drive shaft. An electrical generator is connected to receive and driven by hydraulic fluid flow from the hydraulic pump. A controller receives input indicating electrical power demand on the generator and connected to an actuator on the hydraulic pump, including programmed parameters for operating the hydraulic pump to match flow pressure of the hydraulic pump to the electrical power demand on the generator. Preferably the motor vehicle is a diesel box truck, and the hydraulic pump and generator are mounted to the vehicle frame underneath the rear box. 
         [0006]    According to preferred embodiments of the invention, this system when operated at 1800 rpm will provide 58 cfm of air at about 150 psi. The compressor is a screw type air compressor allowing for a large volume of air at high pressure in a relatively small package. This compressor is belt driven off the truck engine and is mounted on the upper right side of the truck engine. It is necessary to add a crankshaft drive pulley and new idler to accommodate the belt to drive this compressor. The hoses are run from the compressor to the oil/air separator tank located under the driver&#39;s side step. The screw type compressor must use oil to lubricate the rotors while they are compressing the air. This gives a continuous smooth flow of compressed air. Since dry, clean air is needed for the tools used in the spray foam process, an air/oil separator and air drier treat the air before it is fed to a distribution manifold. 
         [0007]    The vehicle has a power take off system that is connected to the transmission of the vehicle, which includes a secondary drive shaft and a second control system for engaging and disengaging the power take off. The secondary drive shaft engages and operates a closed-loop hydraulic pump which is connected to and drives an electrical generator by hydraulic fluid flow. The hydraulic pump and electrical generator are mounted to the vehicle frame underneath the rear box. A controller receives input indicating electrical power demand from the generator, and is connected to an actuator on the hydraulic pump, which possesses pre-programmed parameters for operating the hydraulic pump to match flow pressure of the hydraulic pump to the electrical power demand on the generator. These and other aspects of the invention are discussed in the detailed description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a top view showing the positions at which components according to the invention are mounted on the truck frame (box and other truck features omitted.) 
           [0009]      FIG. 2  is a side view of the components mounted on the truck frame of  FIG. 1   
           [0010]      FIG. 3  is a schematic diagram showing the operative connections between the PTO, closed loop hydraulic pump and the generator; 
           [0011]      FIG. 4  is a schematic diagram showing the operative connections between the air compressor and generator according to the invention with components of the spray foam installation system; 
           [0012]      FIG. 5  is a schematic diagram of connections for the hydraulic pump controller according to one example of the invention; 
           [0013]      FIG. 6  is a side view of the engine block showing the engine belt drive used to power the air compressor (VMAC). 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Referring to  FIGS. 1 through 6 , a truck  13  according to the invention has a frame  10  on which an insulation spraying system  11  and a hydraulic generator system  25  are mounted. A truck box  26  mounted on frame  10  is of conventional design and provides space for the components of spraying system  11  as described below. 
         [0015]    Components of the system are installed on truck  13  in a manner that optimizes use of space inside of box  9  by mounting components in the cab, under the hood and under the frame as needed. For example, referring to  FIG. 6 , mounted on the upper right side of a truck engine  92  is an air compressor (VMAC)  28 . A set of hoses  17  run from the air compressor (VMAC)  28  to an oil/air separator  74  which is mounted under the driver&#39;s side step. Set in the dash of a truck cab  20  is a control console  12  for operating the insulation spraying system  11 . Inset in the driver&#39;s side wall of a truck box  26  is an entry door  37 , permitting access to the interior of the truck box  26 . Mounted on the wall to the front of the vehicle in the interior of the truck box  26  is a GSC control box  38  providing user control of the hydraulic generator system  25 . Mounted atop of the truck box  26  towards the rear of the vehicle is an AC/Heat conditioning unit  40 . 
         [0016]    A PTO (Powered Take-Off system)  14  is mounted on an Allison transmission  15  and controlled through the cruise circuit of the engine  92  located on the central underside of the truck cab  20 . The PTO  14  is connected to and drives a hydraulic pump  16  through a PTO secondary drive shaft  18 , causing the hydraulic pump  16  to turn at a constant speed when engaged by the PTO  14 . The hydraulic pump  16  is part of the hydraulic generator system  25 , which is located beneath the truck box  26 . 
         [0017]    Hydraulic pump  16  supplies a constant flow of hydraulic fluid to a hydraulic motor  22  of a generator  24  to maintain the needed  1800  rpm regardless of load condition, providing steady power to the generator  24 . The hydraulic fluid is provided by a hydraulic resevoir  34 , and remains in a closed loop during operation. While passing through pump  16 , the fluid passes through a hydraulic filter  32 . After a full revolution, the hydraulic fluid is cooled by a hydraulic air cooler  36  and returns to the resevoir  34 . 
         [0018]    The load on generator  24  fluctuates depending on the number of devices in use at a time. To allow the generator  24  to operate smoothly, a control system  42  regulates power flow to the generator  24 . A generator speed controller (GSC)  54  of the control system  42  receives input directly from the generator  24  and monitors changes in voltage. As shown in  FIG. 5 , the GSC  54  outputs are connected to a solenoid  56  that operates the swash plate of the hydraulic pump  16  to control hydraulic fluid flow. A breaker box  44  acts as a buffer between the GSC  54  and the generator  24  to protect the generator  24  in case of electrical overload. Hydraulic pressures can be viewed by the operator by means of a set of hydraulic gauges  30 , which face outwardly from the underside of the truck box  26  towards the driver&#39;s side corner for user access. 
         [0019]    Referring now to  FIG. 4 , the insulation spraying system  11  is depicted in schematic form. The air compressor (VMAC)  28  is needed to supply sufficient air for a breathing system  64 , a set of chemical pumps  66 , a spray gun  68 , and a set of air operated knives  70 . As shown in  FIG. 6 , air compressor (VMAC)  28  is on the upper right side of, and is belt driven by, the truck engine  92 . Hoses  17  are run from the air compressor (VMAC)  28  to the oil/air separator  74  and then to a tank  76 , both of which are located under the driver&#39;s side step. After reaching tank  76 , the air is fed to an air drier  78  for drying, and then to a set of air distribution manifold compartments  80 A and  80 B, which distribute the flow of air to the separate subsystems as shown. To feed ready insulation to the spray gun  68 , compressed air from air manifold  80 A is fed to the chemical pumps  66 , which pump insulation reactants from a reactant tank A ( 82 ) and a reactant tank B ( 84 ), pushing their respective reactant chemicals into an E-30 reactor  86 , where the reactants are kept seperate and heated. From the E-30 reactor  86 , the heated reactants flow to the spray gun  68  through a pair of hoses  90  and  91 . At gun  68  they are combined and pressurized to form the ready insulation compound, and finally expelled in the form of foam by means of compressed air from an air hose  88  connected to air manifold compartment  80 B. The air manifold compartment  80 B also provides air to the air knives  70  and the breathing system  64 . Air flow to the manifold compartments from the air drier  78  is controlled by regulators  81 A and  81 B, while air flow from the manifold compartments to breathing system  64  is controlled by regulator  81 C. 
         [0020]    Referring now to  FIG. 6 , the air compressor (VMAC)  28  is mounted on the upper right side of the engine  92 , and is engaged and disengaged by an air compressor clutch  94  which is driven by an air compressor belt  96 . The air compressor belt  96  is ultimately driven by the engine crankshaft  97  through a crankshaft drive pulley  98 , and the connection between the two is secured by a pair of stabilizer pulleys  100 A and  100 B. Hoses  17  run from the air compressor (VMAC)  28  to the oil/air separator  74  (not shown in  FIG. 6 ). 
         [0021]    A motor vehicle according to the invention thus provides a portable, self-contained foam injection system wherein the major powered components are controlled and powered by the vehicle rather than separate stand-alone devices such as a gas-powered electrical generator which would take up space inside of the truck box. If the truck is used only for transporting the components of the foam spray system then a much larger and hence more expensive truck is needed. The present invention remedies this problem while providing control systems that regulate the amount of power from the truck engine that is used to power the spray system components. 
         [0022]    Although several embodiments of the present invention have been described in the foregoing detailed description and illustrated in the accompanying drawings, it will be understood by those skilled in the art that the invention is not limited to the embodiments disclosed but is capable of numerous rearrangements, substitutions and modifications without departing from the spirit of the invention. A controller for purposes of the invention may be a single control unit that operates the various components, or two or more controllers that work together as described above. The motor vehicle is preferably a truck but other vehicle types may be suitable, such as RV&#39;s and vans. These and other modifications are within the scope of the invention as expressed in the appended claims.