Abstract:
An automatic nailing assembly includes lower and upper skeletal frames for attachment to a pneumatic nailer; front and rear wheels mounted on the bottom frame; a linkage defined by pulleys or sprockets mounted on the frames interconnected by an endless belt or chain and driven by the rear wheel; a cam wheel for rotation by the pulley or sprocket on the upper frame; and a lever operated by the cam wheel to actuate a trigger for causing nails to be ejected at intervals from the nailer as the assembly rolls along a workpiece.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority on U.S. Provisional Patent Application 61/202,781 filed Apr. 3, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to an automatic nailing assembly. 
         [0004]    2. Description of Related Art 
         [0005]    There are many continuous nailing apparatuses of generally the type described herein. Examples of such apparatuses are found in U.S. Pat. Nos. 2,915,754, issued to Oscar A. Wandel on Dec. 8, 1959, 3,796,365, issued to Hugh N. Downing on Mar. 12, 1974, 3,984,040 issued to Arnold H. Fry on Oct. 5, 1976, 3,930,604 issued Roy S. Pitkin, Jr., et al on Jan. 6, 1976, 4,084,738, issued to Fredric H. Schneider on Apr. 18, 1978, 4,225,074, issued to Gerald D. Jacobson on Sep. 30, 1980, 4,523,706, issued to Norman S. Haley on Jun. 18, 1985, 5,110,027 issued to Allen C. Burlingame on May 5, 1992, 5,749,508 issued to Darrell C. Clothier on May 12, 1998, 6,269,996 issued to Richard Lynn McAllister on Aug. 7, 2001, 6,543,663, issued to David M. Davis on Apr. 8, 2003 and 6,712,256, issued to Kevin James Curry on Mar. 30, 2004. 
         [0006]    In spite of a relatively large number of patents and applications relating to the subject matter in question, a need still exists for a simple automatic nailing apparatus which is easy and inexpensive to manufacture. The present invention is intended to meet such need. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    Accordingly, the automatic nailing assembly of the present invention includes bottom and top skeletal frames for attachment to an off-the-shelf pneumatic nailer, front and rear wheels mounted on the bottom frame, pulley or sprockets mounted on the frames interconnected by a v-belt or chain and driven by the rear wheel, a cam wheel for rotation by the pulley or sprocket on the top frame, and a lever operated by the cam wheel to actuate a trigger to cause a nail to be ejected from the nailer. By rolling the nailer along a workpiece, nails are automatically intermittently ejected from the nailer, the spacing between the nails being dependent upon the speed of travel of the assembly along the workpiece. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The preferred embodiment of the invention is described below with reference to the accompanying drawings, wherein: 
           [0009]      FIGS. 1 and 2  are isometric views of a nailing assembly in accordance with the invention from opposite sides and ends; 
           [0010]      FIG. 3  is a side view of the assembly of  FIGS. 1 and 2 ; 
           [0011]      FIG. 4  is a side view of the assembly of  FIGS. 1 to 3  with an element of the assembly shown in phantom outline; 
           [0012]      FIG. 5  is a top view of the assembly of  FIGS. 1 to 4 ; 
           [0013]      FIG. 6  is a bottom view of the assembly of  FIGS. 1 to 2 ; 
           [0014]      FIG. 7  is an isometric view of the top portion of a trigger release used in the nailer assembly of  FIGS. 1 to 6 ; 
           [0015]      FIG. 8  is a top view of a cam wheel and lever system used in the assembly of  FIGS. 1 to 6 ; and 
           [0016]      FIGS. 9 and 10  are side views of the cam wheel and lever of  FIG. 7  illustrating operation of the cam wheel and lever. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Referring to the drawings, the automatic nailing assembly of the present invention is intended for use with a conventional, off-the-shelf pneumatic nailer, which is indicated generally at  1  in  FIGS. 1 to 3 . In this case, the nailer  1  carried the name “Campbell Hausfeld”. The nailer  1  includes a housing  2  with a coupler  3  at one end thereof for receiving a hose  4  ( FIG. 3 ). The hose  4  is connected to a compressor (not shown) for introducing air under pressure into the housing  2  to operate the nailer. Nails (not shown) are housed in a magazine  5  beneath the housing  2  for ejection through an opening  6  ( FIG. 6 ) in a neck  7  extending downwardly from the head  8  of the housing  2 . 
         [0018]    During use, a trigger release  9  is pressed against a workpiece such as a sheet of plywood or particle board. The trigger release  9  ( FIGS. 1 and 7 ) includes a wire  10  extending around the discharge end of the neck  7  and a generally L-shaped arm  11 . When the release mechanism  9  is pushed upwardly it releases a normally manually operated trigger  12 . Depressing the trigger  12  causes ejection of a nail. The nailer is then moved manually to another location and the process is repeated. 
         [0019]    The nailing assembly of the present invention is mounted on and carries the nailer. The basic elements of the assembly are skeletal lower and upper frames indicated generally at  13  and  14 , respectively. The lower frame  13  is mounted on the bottom of the nailer, and the upper frame  14  is connected at a front end to the housing  2  and at a rear end to an arm  15  extending downwardly from the rear end of the housing  2 . 
         [0020]    The lower frame  13  includes a rear section defined by a pair of sides  16  bolted to the bottom rear end of the magazine  6 . The sides  16  have inverted L-shaped cross section front ends  18  and straight, vertical rear ends  19  extending rearwardly beyond the rear end of the magazine  5 . The ends  19  receive a shaft  20  carrying a rear wheel  21 , which can be studded for increased traction. A pulley  23  is mounted on an end of the shaft  20  extending outwardly beyond the wheel  21  and one rear side  16  of the frame  18 . 
         [0021]    A front section of the lower frame  13  is defined by arms  24  pivotally connected to the leading ends of the sides  16  by bolts  25 . The arms  24  diverge from the magazine  6  and then converge to a location beyond the front end of the nailer. The outer free ends  26  of the arms  24  support a front wheel or roller  27 . An inverted U-shaped trigger release arm or crossbar  28  extends between the arms  24  at the junction between the diverging and converging ends thereof. The center of the crossbar  28  carries the L-shaped arm  11  of the trigger release  9 . A helical spring  31  is mounted on the horizontal arm of the trigger release  9 . The vertical arm of the release  9  extends into a square cross section tube  32  ( FIGS. 3 and 4 ) fixedly mounted beneath the trigger  12  of the nailer. The tube  32  is mounted between the sides  33  of the trigger bracket. When the release  9  moves upwardly, a shoulder  34  ( FIG. 3 ) on one side of the vertical arm of the release engages the bottom end of the tube  32  to limit upward movement of the release. 
         [0022]    In use, when the assembly is pressed against the surface of a workpiece to receive nails, e.g. a sheet of plywood, the front wheel  27  is pushed upwardly causing the arms  24  to rotate around the axes of the bolts  25 . The vertical inner end of the trigger release arm  11  moves upwardly into the tube  32 . When the wheel  27  is removed from contact with the surface receiving nails, the spring  31  returns the trigger release  9  and the front end of the frame  13  to the rest positions. 
         [0023]    The upper frame  14  includes a pair of sides  35 , which are connected at their front ends to the trigger bracket sides and at their rear ends to the arm  15  extending downwardly from the nailer housing  2 . The arm  15  also supports the top end of a bracket  37  connecting the rear end of the magazine  6  to the housing  2 . A cam wheel  38  is rotatably mounted in the upper frame on a shaft defined by a bolt  39  extending through the sides  35  of the upper frame  15 . An outer free end of the bolt  39  carries a pulley  40  which is vertically aligned with the pulley  23  on the outer end of the rear wheel shaft  20 . An endless V-belt  42  extends around the pulleys  23  and  40 . The pulleys  23  and  40  are adjustable so that the tension on the belt and the spacing of the nails can easily be adjusted. Rotation of the rear wheel  21  during movement of the nailer assembly along a surface causes corresponding rotation of the pulleys  23  and  40 , and consequently rotation of the cam wheel  38 . It will be appreciated that the pulleys  23  and  40 , and the V-belt  42  can be replaced by sprockets and a chain (not shown). 
         [0024]    As best shown in  FIGS. 4 and 8  to  10 , the cam wheel  38  is shaped like a pulley with two sides  43 . Each of the sides has a sawtooth periphery defined by alternating teeth or lobes  44  and grooves  45 . A generally inverted V-shaped lever  47  is pivotally mounted in the upper frame  14  by means of a rod  48  extending outwardly from the trailing end of the lever  47  into the sides of the frame  14 . A second rod  49  forwardly of the rod  48  extends outwardly from the sides of the lever  47  into overlapping relationship with the sides  43  of the cam wheel  38 . As the wheel  38  rotates (counterclockwise in  FIGS. 4 ,  9  and  10 ), the rod  49  slides up on the teeth  45  causing the lever  47  to pivot around the axis of the rod  48 . Thus, the leading end  50  ( FIG. 8 ) of the lever  47  is forced upwardly. Such leading end  50  of the lever is connected by a helical spring  52  to an arm  53  of the trigger  12  pivotally mounted between the sides of the trigger bracket. 
         [0025]    An elongated handle (not shown) can be connected to the nailer  1  or to the upper frame  14  for pushing the assembly along a workpiece surface. In operation, for example when prefabricating a wall on a horizontal surface, the handle is used to push the assembly along a line marked on a panel being attached to framing. Alternatively, a laser pointer (not shown) can be attached to the nailer or to one of the frames  13  and  14  for providing a line on the workpiece. When the assembly is placed on the panel, the arms  24  of the lower frame  13  pivot around the bolts  25  so that the front wheel  27  moves upwardly and the trigger release  9  is depressed. 
         [0026]    During movement of the assembly along the panel, rotation of the rear wheel  21  causes a corresponding rotation of the pulley  23 . The V-belt  42  transmits such rotation to the pulley  40 , which causes rotation of the cam wheel  38 . As the cam wheel  38  rotates, the teeth  45  periodically engage the rod  49  causing the lever  47  to pivot to a trigger operating position to eject a nail from the nailer  1 . The spacing of the nails is changed by adjusting the pulleys  23  and  40 . If the rear pulley  20  is rotated clockwise (in the arrangement of  FIGS. 1 and 3 ), the belt  42  is caused to run on a larger diameter area of the pulley. Turning of the front pulley  40  in a counterclockwise direction loosens the pulley, permitting the belt  42  to run on a smaller diameter. A larger diameter rear pulley  20  in combination with a smaller diameter front pulley  40  increases the frequency of trigger actuation and consequently closer spacing of the nails. Of course, the reverse is true when it is desired to increase the spacing of the nails. Thus, the adjustable pulleys allows for precise adjustment of nail spacing. The spacing of the nails can also be changed by replacing the cam wheel  38  with another cam wheel having more or less teeth. Obviously, the faster the movement of the assembly along a work surface the more frequent the occurrence of a nailing operation. In the absence of a handle, the nailer is pushed manually along the work surface.