Abstract:
A machine for clamping material to be fastened and automatically installing screws has been disclosed through a method of a self loading barrel that also aligns the screw to be installed thus reliving the operator of the strain of holding an unstable screw in place during the driving phase. This machine also automatically provides the force needed to keep the fastener from stripping at the head driver connection point through its unique design and also reliving the operator of much of the work related strain associated with these operations. This tool also provides another benefit in its design by automatically clamping the material during the fastening operation, that would normally have to be done separately with another tool. Another embodiment permits single loading of fasteners into the barrel.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
         [0001]    Not Applicable  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable  
         BACKGROUND OF THE INVENTION  
         [0003]    This invention relates generally to the field of fastening light gauge metals, and more particularly to a machine for clamping material to be fastened and automatically installing screws.  
           [0004]    Screws are the fastener of choice in construction of sheet metal and steel stud construction. For many years workers have been using various types of screw guns that are somewhat efficient in their operation but are relatively slow and cumbersome to operate due to several problems. First, the material to be fastened usually needs to be fastened with a clamp to hold the material in position and tightly together to accomplish a strong connection. Second, the operator must apply sufficient force behind the fastener to drive it properly which can be difficult or impossible if the operator is in a awkward or dangerous position. A similar system for clamping material but using a two part fastener was disclosed in U.S. Pat. No. 6,148,507 to Swanson, et al.  
           [0005]    Other screw guns that are available are capable of self loading their fasteners into position for the next driving operation. These screw guns are very capable for their intended use for fastening drywall materials, wood, and plywood sheeting to already constructed steel stud members, but do not provide what is needed for the framing construction phase using metal studs as described below. The material still must be separately clamped by another device, the operator must use their own strength to apply force behind the fastener during the driving phase, and these tool provide little or no assistance for holding the fastener in its position during installation.  
           [0006]    The problem with the existing technology is that the material still must be separately clamped by another device, the operator must use their own strength to apply force behind the fastener during the driving phase, and these tool provide little or no assistance for holding the fastener in its position during installation. The tool of the present invention relieves the operator of much of the physical counteractive forces that need to be applied by the hand, wrist, and arm during the work of installation. This will also help protect the operator of more nerve damage associated with this type of work. This new design installs fasteners faster, more correctly and consistent, and with less demand on the part of the operator.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    The primary object of the invention is to provide a screw gun that automatically clamps the material to be fastened.  
           [0008]    Another object of the invention is to provide a screw gun that automatically applies the pressure needed to drive the screw into place.  
           [0009]    Another object of the invention is to provide a screw gun that holds the screw in its driving position until securely driven.  
           [0010]    Another object of the invention is to eliminate the need of a separate tool for clamping the two materials that will be fastened.  
           [0011]    Another object of the invention is to have a tool that provides the force needed behind the fastener, during the driving phase of the fastener, while also providing equal force opposite the fastener inside the tool completely isolated from the operator. This will require much less physical demand from the operator when using the tool, and thus provide greater protection for the operator against hand and wrist work related injuries through tight grips, vibration, and torque associated with typical screw guns.  
           [0012]    Another object of the invention is to have a tool that combines clamping the material, automatic loading of a fastener, and driving the fastener in one compact light tool. This will eliminate two separate tools that are needed now, and at the same time improve the quality and the speed of installing fasteners over current technology.  
           [0013]    In accordance with a preferred embodiment of the invention, there is disclosed a machine tool for loading screw fasteners automatically, clamping the material to be fastened, applying the force necessary to install the fastener.  
           [0014]    Other objects and advantages will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL DRAWINGS  
       [0015]    The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.  
         [0016]    [0016]FIG. 1 is a perspective, partially exposed view of the screw gun of the present invention.  
         [0017]    [0017]FIG. 2 is a cross sectional view of the screw gun with a loaded fastener.  
         [0018]    [0018]FIG. 3 is a cross sectional view of the screw gun with the fastener screwed into the material being fastened.  
         [0019]    [0019]FIG. 4 is a cross sectional enlarged view of the invention&#39;s self loading barrel.  
         [0020]    [0020]FIG. 5 is a pneumatic schematic of a circuit embodied in the invention.  
         [0021]    [0021]FIG. 6 is a flow chart of the operations that comprise the method of the invention.  
         [0022]    [0022]FIG. 7 is a perspective view of the alternate barrel assembly.  
         [0023]    [0023]FIG. 8 is a cross sectional view of the manual loading barrel.  
         [0024]    [0024]FIG. 9 is a cross sectional view showing the screw alignment feature.  
         [0025]    [0025]FIG. 10 is a cross sectional view showing the operation of the screw alignment feature.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    Detailed descriptions of the preferred embodiments are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Various aspects of the invention may be inverted, or changed in reference to specific part shape and detail, part location, or part composition. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.  
         [0027]    Turning first to FIG. 1, there is shown a perspective partially exposed view of the portable fastener tool of the present invention. Tool handle  20  provides the means for holding the tool which houses switch  62 , upper air valve  61 , and lower air valve  60  for operating the tool. Pneumatic hose  66  provides the air power needed for operating the tool by means of an air compressor not shown, but well known to those of skill in the art. Magazine fastener  70  holds a strip of pre assembled fasteners which are pushed into barrel clamp  26  by fastener pusher  75 , the connection between the preassembled fasteners  90  and fastener pusher  75  is made by articulating pusher arm  74 . Spring tape  73  and spring tape reel  72  provides the force needed to move fastener pusher  75  thus providing a means to load fastener guide  90  and screw  91  into barrel clamp  26 . Tool handle  20  also provides a frame for various separate components to be combined into one tool. Air motor  63  is mounted inside frame  22  which is part of the tool frame, frame  22  holds gear box  30  and air motor  63  in place. Air motor  63  provides rotating power to gear box  30 , which is then transferred to screw shaft  31 , that is connected to screw driver tip  33 , which can be removed for different type of driver tips so that different screws may be used. Exhaust air from motor  63  is vented through two exhaust ports  29 . The connection between screw shaft  31  and screw driver tip  33 , is made through shaft yoke  32 . The force needed for clamping the material, loading, and driving the screw is developed by piston  41  that is located inside air cylinder  40 . The power from piston  41  is transferred to two connecting rods  42 , to material clamp  28 .  
         [0028]    The view shown in FIG. 2 reveals material  10  to be fastened at the start position of the tool and a better view of the various components of the tool and air passages. Barrel clamp  26  is in the fully extended position with a loaded screw  91  and fastener guide  90 . Next material  10  to be fastened is placed in the breach between material clamp  28  and barrel clamp  26 , at this time the operator will press start switch  62  which will reposition upper and lower air valves  61  and  60 . Pressurized air from supply line  50  will now be allowed to start to enter motor-piston supply line  51 . Air now will begin to move piston  41  to the opposite side of cylinder  40 , the air on the opposite side of the piston will be vented first through cylinder cap  57 , then line connector  56 , next secondary air cylinder line  55  into the now opened lower air valve  60 , and out lower exhaust port  64 . Air that is not used for the above operation will continue to travel upward toward air directional block  53  into air motor  63  and vented out upper exhaust ports  59 . Now the motor will provide the power needed to drill the screw through the connection between the motor and screw driver tip  33 . During this operation pressure will continue to build against piston  41  which will be transferred through connecting rods  42  to material clamp  28 . Pressure opposite this to clamp the material will be provided by barrel clamp  26  and the resistance of two compression springs  44 , spring rods  43 , and spring seat  27 . The barrel clamp and material clamp will slide through the guides in guide fork  24 . The screw will slide through the bore within barrel clamp  26 .  
         [0029]    [0029]FIG. 3 shows material  10  is fastened by the screw  91 . At this point the operator will release switch  62  and upper air valve  61  and lower air valve  60  will return to their original position, air pressure from piston  41  and motor-piston supply line will automatically vent trough motor and upper exhaust ports  59  after the air supply is cut off. Air from supply line  50  will now be able to enter the now closed piston exhaust circuit through air manifold  54 , into secondary air cylinder line  55 , trough line connector  56 , and cylinder cap  57 , into cylinder  40 , now pushing piston  41  in the opposite direction. This will now cause connecting rods  42  to push the material clamp to its open position allowing barrel clamp  26  to be pushed back to its self loading position by compression springs  44 . Once the barrel clamp is returned to its load position the next fastener can be loaded from magazine  70  and the pressure provided by spring tape  73  transferred through pusher arm  74 .  
         [0030]    The next view shown in FIG. 4 shows an enlarged view of barrel clamp  26  and how fastener guide  90  and fastener  91  enter and fit into the bore  25  of the barrel clamp and the position of magazine  70 , and the screw driver tip.  
         [0031]    [0031]FIG. 5 presents a schematic representation of pneumatic system  500  of the preferred tool screw fastener system. In general, the preferred system  500  includes air compressor power supply  510  which is connected to fastener tool  520 . Control of the pneumatic system is through start switch  62  (not shown in this drawing) acting on air pressure regulator  512  which in turn causes the selective depression of lower valve  560  and upper valve  561  on the tool. In the neutral position, as shown in the schematic, air is allowed to enter only one side of air cylinder  540  from valve  560  pushing piston  542  to its start position in air cylinder  540 . When the air valves are pushed to their run positions, air is rerouted to the motor, and also to the opposite side of the piston in air cylinder  540  from valve  561 . Also the lower air valve opens vent  563  for air cylinder  540  to vent its start position pressure.  
         [0032]    [0032]FIG. 6 presents a flow chart of the tools fastening operation beginning when the material is ready to be clamped at step  1000 . In general, this preferred system is operated by pushing tools start switch at step  1001 , which provides pressure on the piston that causes the clamping of material to be fastened at step  1002  and also starts the motor that turns the screw driver tip that drills screw at step  1003 , next the screw is driven into the material fastening the material at step  1004 . Now the operator will release the switch to stop the operation at step  1005 , the piston will return to start position at step  1006 , and the tool is ready for the next operation at step  1007 .  
         [0033]    The view shown in FIG. 7 shows a perspective view of the alternate barrel loading assembly to be used in place of the self loading barrel clamp previously described. Barrel clamp  100  holds the various components for loading, positioning the screw, and clamping the material. Fastener guide  102  provides the chamber for holding the screw until driven, the screw is loaded into the fastener guide through chamber opening  105 , guide spring  103  (shown in FIG. 8), is not shown for clarity. Screw  91  is positioned perpendicular to the material by means of alignment forks  104  which also has chamber opening  105 . Alignment forks  104  are permitted to open by fork grooves  101  in barrel clamp  100 . Also driver head  33  is shown in this view.  
         [0034]    The view shown in FIG. 8 reveals the start position of the tool with the various components of the alternate barrel clamp. Material clamp  28  is in the full open position, opposite of barrel clamp  100 , at this time the operator will load a single screw  91  through chamber opening  105  into fastener guide  102  which is a hollow tube at the center of the various components with a spring seat  108  at the right end. The pressure for providing the fastener guide to return to its normal start position is the guide spring  103 . The alignment forks  104  are shown in their closed position within opening  109 , which has slits cut in the length direction of the opening that allows for the forks to open for passage of the screw.  
         [0035]    The view shown in FIG. 9 shows fastener  91  pushed and engaged by drive  33 , which rotates to drill the screw. The screw at this time is forced to align itself perpendicular to the material due to the design of alignment forks  104 . At this point push ring  106  will start to engage the back of fastener guide  102 , and spring seat  108 , which will provide the force to push the fastener guide through the center and open alignment forks  104 , with out the screw or the driver making contact with the forks, which will be described in connection with FIG. 10. Also material  10  is clamped in the same manner as described in FIGS. 2 and 3 by means of material clamp  28  and alternate barrel clamp  100 .  
         [0036]    The view shown in FIG. 10 shows material  10  fully fastened and clamped between material clamp  28 , and barrel clamp  100 . As screw  91  is driven fastener guide  102  is also driven forward by push ring  106 . This causes the forward tapered end of fastener guide  102  to be pushed through the center of alignment forks  104  pushing them outwards into the openings provided by barrel fork grooves  101 , opening the passage for the screw head to pass the alignment forks. This also compresses guide spring  103 , which will later provide the energy to push fastener guide  102  to its start position allowing alignment forks  104  to close and the chamber opening to realign to the open position to allow the next screw to be loaded.  
         [0037]    While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as is defined by the appended claims.