Abstract:
An automatic nail fastening device which is capable of adjusting the spacing and patterning of the nails is presented which is especially useful for nailing decking to a roof. The device is also capable of identifying metal having a predetermined thickness in the underlying substrate so that nailing into such metal contained in the underlying substrate can be avoided.

Description:
FIELD OF INVENTION  
         [0001]    The present invention generally relates to an automatic nail fastening device which is controlled by a microprocessor and more particularly relates to an automatic nailing device for nailing roof decking.  
         BACKGROUND OF THE INVENTION  
         [0002]    Automatic apparatus for installing shingles on a roof are known in the art. For example, U.S. Pat. No. 5,169,048 issued to Himebaugh discloses an automated shingling apparatus for applying strips of shingling material to a roof which includes a frame having a motorized drive belt assembly. A roll of shingling strip material is carried on the frame and movement of the belt assembly unwinds the shingling material from the roll and deposits it on the roof. A series of actuators are mounted on the drive belt and as the assembly belt moves, the actuators pass by and periodically engage the trigger of a nail gun positioned on the frame thereby fastening the shingling material to the roof in timed relation to the movement of the apparatus.  
           [0003]    Another automatic shingling patent, namely U.S. Pat. No. 5,381,597 issued to Petrove, discloses a shingling apparatus that applies shingles to a roof in successive steps. The apparatus includes a frame having a wheel assembly with air driven motors to vertically move the apparatus. A hopper on the frame holds the shingles while a shuffle bar moves across the shingles, placing them one at a time onto forks. The forks move from the frame to the roof where the shingle is placed and then fastened to the roof with a pneumatic nail gun. When the forks return to their starting position to retrieve the next shingle, the apparatus moves toward the top of the roof in a vertical direction. The apparatus is attached to nylon belts which are fastened at the top of the roof to a linear motion brace. The movement of the apparatus is performed through the use of many sensors and a microprocessing system.  
           [0004]    The present invention differs from the automatic shingling apparatus of the prior art in that it is directed toward an automatic nailing device that is capable of nailing decking to a roof, especially commercial roof deck, instead of nailing shingling to a roof deck. Nailing of roof deck to a roof frame may require various spacing and patterning of the nails to accommodate different types of roof structures. Accordingly, an automatic nailing apparatus is needed which is capable of automatically nailing decking to a roof structure where the spacing and patterning of the nails can be altered according to the roof structure. There is also a need for an automatic nailing apparatus for nailing decking to a roof which can identify metal plates which exceed a predetermined thickness and which are attached to the roof structure so that nailing into the metal plates of the roof structure can be avoided.  
         SUMMARY OF THE INVENTION  
         [0005]    It is a principal object of the present invention to provide an automatic nail fastening device which is capable of adjusting the spacing and patterning of the nails.  
           [0006]    It is another object of the present invention to provide an automatic nail fastening device which is especially useful for nailing decking to a roof and which is also capable of identifying metal having a predetermined thickness in the underlying roof structure so that nailing into metal contained in the underlying roof structure can be avoided.  
           [0007]    The present invention comprises an automatic nail fastening device having a frame, at least one wheel attached to the frame to allow for movement of the frame, at least one nail gun attached to the frame and means for activating the nail gun such as, for example, a pneumatic system where pressurized air can be used to activate the nail gun, a sensor for sensing a distance traveled which sends a signal to a microprocessor regarding the distance traveled, the microprocessor receiving the signal from the sensor and controlling the means for activating the nail gun, and a power source for the microprocessor.  
           [0008]    In another aspect of the invention, the automatic nail fastening device may include a detector for sensing metal which exceeds a predetermined thickness or threshold level that is located in the path of the nail gun where the detector sends a signal to the microprocessor to prevent the nail gun from nailing into the metal.  
           [0009]    In still another aspect of the invention, the microprocessor is capable of controlling the spacing and pattern of the nails that are nailed with the nail gun.  
           [0010]    In yet another aspect of the invention, the automatic nail fastening device includes means for feeding nails into the nail gun.  
           [0011]    In yet another aspect of the device, a pair of handles and a control panel may be included. The handles allow a user to more easily push the device. Safety levers and a push button for manually activating the nail gun may also be positioned near the handles to enable easy access to such features by the user. The control panel may include an “on/off” switch, means for selecting the spacing and or pattern of the nails, and one or more light emitting diodes for indicating device status such as low battery, inaccurate nail spacing and realignment for proper spacing, and whether the device is on or off.  
           [0012]    The present invention also includes a method for automatically fastening nails to a substrate which includes the steps of providing a device having a frame, at least one nail gun mounted to the frame, means for activating the nail gun, and means for moving the frame, locating an edge of the substrate with the device, inputting spacing and/or patterning of the nails into a microprocessor, moving the device along the substrate, sensing a distance traveled by the device and sending a signal to the microprocessor in relation to the distance traveled, receiving the signal with the microprocessor, and activating the nail gun in response to the received signal. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    Additional aspects of the present invention should become evident upon reviewing the non-limiting embodiments described in the specification taken in conjunction with the accompanying figures, wherein like numerals designate like elements, and:  
         [0014]    [0014]FIG. 1 is a perspective view of one embodiment of the automatic nail fastening device of the present invention;  
         [0015]    [0015]FIG. 2 is a top plan view of the control panel and handles of the automatic nail fastening device of the present invention; and  
         [0016]    [0016]FIG. 3 is a top plan view of another embodiment of the automatic nail fastening device of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0017]    The following descriptions are of exemplary embodiments of the invention only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description is intended to provide a convenient illustration for implementing various embodiments of the invention. As will become apparent, various changes may be made in the function and arrangement of the elements described herein without departing from the spirit and scope of the invention. For example, though not specifically described, many shapes and orientations of the frame and positioning of elements on the frame should be understood to fall within the scope of the present invention.  
         [0018]    As shown in FIG. 1, the present invention is generally directed to an automatic nail fastening device  10  which includes a frame  12 , at least one wheel  14  attached to the frame  12  to enable movement of the frame  12 , at least one nail gun  16  attached to the frame  12  and means for activating the nail gun  16 , a sensor  18  attached to the wheel  16  of the frame  12  for sensing a distance traveled wherein the sensor  18  is capable of sending a signal in relation to the distance traveled, a microprocessor  20  for receiving the signal from the sensor  18  and for controlling the means for activating the nail gun  16 , such as, for example, Microchip microprocessor 17C756 which is programmed to control operations of the device, and a power source (See FIG. 2) for the microprocessor  20 . The embodiment of the automatic nail fastening device  10  shown in FIG. 1 includes two wheels  14  positioned in parallel and a third wheel  14  positioned equidistant between the parallel wheels  14  but at a predetermined length away from parallel wheels  14 , and two nail guns  16  attached to the frame.  
         [0019]    This embodiment also shows pneumatic means for activating the nail guns  16  which comprises pneumatic nail guns  16  each having a housing  22  containing pressurized air and means for retaining nails, and a handle  24  attached to the housing. Guns  16  are attached to frame  12  by mounting each nail gun  16  on a pivoting mechanism located near the end of handles  24  which is in turn mounted to frame  12 . Nail guns  16  used in the present invention are standard nail guns or roofing guns which utilize pneumatic actuators such as, for example, guns having product number NV83A manufactured by Hitachi. In employing a standard nail gun or roofing gun, a user depresses a trigger on the handle of the gun and then taps the nose of the gun to the substrate or decking to be nailed in order to depress a nose safety release on the gun which is also known as a probe tip or touch probe. A nail is fired once the probe tip is sufficiently depressed and the tip must be completely released before another nail can be fired.  
         [0020]    In the present invention, the trigger on handle  24  is retained in a depressed position by a restraint such as a rubber bungee cord or the like. Nail guns  16  are mounted on a pivoting mechanism which is held away from the substrate or roofing deck by a pneumatic actuator  23 . In order to carry out the firing of a nail, the microprocessor sends a signal to an air control valve  26  which in turn removes air pressure from the actuator air cylinder  23  which then allows gun  16  to fall to the substrate or roof decking. When gun  16  falls to the substrate or decking, the probe tip on gun  16  is depressed and a nail is fired. Air control valve  26  may actually comprise a plurality of air control valves which control the air pressure that functions to operate various elements of the device. Wires connect each air control valve to microprocessor  20 .  
         [0021]    After a predetermined amount of time, air control valve  26  is de-energized which results in putting pressure on actuating air cylinder  23  thereby returning gun  16  to its upright non-firing position. It will be understood by those skilled in the art that additional downward force may also be applied to gun  16  instead of relying on the force of gravity alone to drop gun  16  to the substrate or roof decking. Examples of means for applying additional downward force include, but are not limited to, using an external spring, or supplying air pressure to the other side of actuating air cylinder  23 .  
         [0022]    A lubricator  30  for adding an oil mist to the air system and an air accumulator  32  may each be connected to actuating air cylinder  23  by way of air hoses  34 . An air pressure regulator  28  controls the nailing force of gun  16  thereby controlling how hard the nail is driven into a substrate or roof decking. In addition, a regulator for controlling the air pressure of actuating air cylinder  23  (in order to control how hard gun  16  is returned to an upright non-firing position) and a regulator for controlling how much downward force is applied on actuating air cylinder  23  to drive gun  16  to a substrate or roof decking.  
         [0023]    The embodiment in FIG. 1 also shows means for feeding nails into the nail guns  16  which comprises coils of nails  36 , where the nails are contained on a backing, which feed into pneumatic nail guns  16 . The coils of nails  36  unroll as nails are fed into pneumatic nail guns  16 . A detector (not shown) may be attached underneath frame  12  in a position so that a predetermined thickness of metal located in the path of nail guns  16  may be detected and result in a signal being sent to microprocessor  20  which controls nail guns  16  so that nail guns  16  will not fire into the metal. A rope  38  is also shown which is used to secure frame  12  while being lifted to a roof for use. Bungee cords  40  are also shown in this embodiment for holding the releases on pneumatic nail guns  16  in the “on” position so that automatic nailing controlled by microprocessor  20  can take place.  
         [0024]    [0024]FIG. 1 also shows one handle  42  of a pair of handles and a control panel  44  which are later described in detail with reference to FIG. 2. In order to facilitate computer control of automatic nail fastening device  10 , microprocessor  20  is attached to control panel  44  which is located such that control panel  44  is in close reach of a user moving the automatic nail fastening device  10  by pushing on the pair of handles.  
         [0025]    A top plan view of the handles  42  and control panel  44  of automatic nail fastening device  10  is shown in FIG. 2. Handles  42  are attached to a support bar  46 . Safety levers  48  and push buttons  50  may also be attached to support bar  46  near handles  42  to enable a user to manually deactivate or activate nail guns  16 .  
         [0026]    Control panel  44  includes a battery  52  which is attached to microprocessor  20  to power microprocessor  20 . Other means may also be used to power microprocessor  20  such as a fuel cell or solar power. Control panel  44  also includes a nailing schedule having means for selecting spacing of the nails, such as dial  54  and means for selecting the pattern of the nails, such as dial  56 . The selection means are connected to the microprocessor  20  which controls nail guns  16 . Control panel  44  may also include one or more light emitting diodes (LEDs) for indicating a status of automatic nail fastening device  10  such as, for example, a low battery LED  58 , an LED  60  to signal inaccurate nail spacing and realignment of the device for proper spacing, and an LED  62  to indicate whether or not device  10  is on or off. The control panel also includes a push button  64  for locating the edge of the substrate to be nailed so that a user can set or reset the device so that it employs the proper nailing pattern. The nailing pattern repeats every two feet when nailing along a four foot edge of roof sheeting and repeats every sixteen feet when nailing along an eight foot edge of roof sheeting. Therefore, the automatic nailing device must start the nailing pattern in a known position relative to the roof sheeting edge. An indicator is attached to frame  12  of the device which is positioned approximately ¼ of an inch above the roof sheeting so that the operator of the device can easily see the indicator from his normal operating position. As the user or operator maneuvers the device into position, the user will push the device forward until the indicator is over the edge of the roofing sheet. The user then presses push button  64  which is connected to microprocessor  20  by a cable. Depressing push button  64  signals to microprocessor  20  that the device is in proper position for starting the designated nail pattern.  
         [0027]    In addition to the above described LEDs, there may also be an LED to indicate that guns  16  are over a metal piece having a predetermined target thickness and are therefore not going to fire. The detector is positioned ahead of guns  16  in the device&#39;s direction of motion. Microprocessor  20  compensate for the distance between the detector and each individual gun  16  thereby enabling it to disable each gun  16  in turn as it later passes over the previously detected metal having a predetermined target thickness.  
         [0028]    Turning now to FIG. 3, a top plan view of another embodiment of automatic nail fastening device  10  is shown. As with the embodiment shown in FIG. 1, device  10  includes frame  12 , wheels  14 , pneumatic air guns  16  each having housing  22  and handle  24 , sensor  18 , microprocessor (not shown), air control valve (not shown), air pressure regulator and filter  28 , lubricator  30 , air accumulator  32 , hoses  34 , nail coils  36 , rope  38 , handles  42 , and control panel  44 . However, in this embodiment, device  10  also includes one or more rails  66  for mounting nail guns  16  thereon so that the position of nail guns  16  can be adjusted along the length of rails  66 . It should be noted that nail guns  16  shown in FIG. 1 are secured to frame  12  with brackets (not shown). It should also be noted that platforms  68  for supporting nail coils  36 , although not shown in FIG. 1, are also present in the embodiment shown in FIG. 1. It will be understood by those skilled in the art that nail guns  16  may also be positioned and secured at an angle for firing.  
         [0029]    The metal detector included in the present invention is located below the front coil of nails on the centerline of the device, and in alignment with guns  16 , approximately six inches in front of the forward most gun. One exemplary embodiment of the metal detector may comprise a rectangular shape that is approximately 1.5 inches in height, 4 inches wide, and 4 inches in length. A single cable connects the detector to the microprocessor of the present invention. An example of a metal detector which can be used in the present invention is a detector manufactured by Turck having product number Bi5OU-Q80-AP6X2-H1141.  
         [0030]    The automatic nail fastening device of the present invention enables decking to be attached to a roof in a fast and efficient manner while still ensuring that the nails are adequately secured in the substrate. Differences in type of substrate can be accommodated for by adjusting the air pressure for the pneumatic nail gun. It should also be understood by those skilled in the art that other means for activating the nail guns may also be used such as electronic means.