Abstract:
A compact single-blow pneumatic nailing tool for installing metal joist hangers and metal plates in wood-constructed houses. A lower nosepiece reciprocates with respect to an upper nosepiece, and, as the lower nosepiece reciprocates, an attached nail magazine moves jointly therewith. A safety linkage connected to the magazine engages a trigger lever and permits the tool to be fired only when the lower nosepiece is pressed against the workpiece. The tool does not need a guide tip or elaborate safety to guide a nail into a hole in the workpiece, and does not have a vision-blocking safety mechanism on the tip of the nose. The tip of the nail sticks out of the nose of the tool, facilitating placement into a hole in the workpiece.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority of pending U.S. Provisional Patent Application 60/733,078, filed Nov. 3, 2005, entitled Single-Blow Pneumatic Nailing Tool, fully included by reference herein. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable.  
       REFERENCE TO COMPACT DISC(S)  
       [0003]     Not applicable.  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     The present invention relates, in general, to pneumatic tools that install metal straps and metal joist hangers as are used to tie the wood construction together and make a stronger house, and in particular, to single-blow nailing tools.  
         [0006]     2. Information Disclosure Statement  
         [0007]     It is often desired to have a compact nailing tool that will fit between the rafters in a house under construction, in which the tool is of a “single-blow” type such that the nail is driven into the work surface in one hit of the driver blade. It is also desired to have a single-blow tool that does not need to use hardened nails and does not need to have a hardened guide tip to locate the hole in the steel. More than anything, it is greatly desired to have a single-blow tool that is safer than prior art tools yet does not have or require a safety mechanism anywhere on the nose of the tool, because such a safety mechanism, if present, obscures the user&#39;s view of the workpiece being nailed.  
         [0008]     Hurricane areas, earthquake areas and tornado areas, including all of the costal areas, use a greater amount of metal straps and hangers. In these high-volume nailing areas it is important to be able to install the large volume of nails required for the job as quickly as possible. There are a number of prior art tools on the market used for such purposes. Tool manufacturers Paslode, Hitachi and Bostitch all use large framing nail guns to do this job.  
         [0009]     There are a number of major problems with such prior art tools. The first problem is that the tools are very large and tall and they will not fit into small places, like between the rafters where metal rafter tie-downs are often installed. Another problem with two of these tools is that they need to have a hardened guide tip to guide the nail into the hole in the steel plate workpiece. In other words, the hardened guide tip of prior art tools acts as an elaborate safety mechanism, which, in turn, causes several additional problems. Because they need a guide tip to help the nail to locate the hole, they must use a hardened steel nail, which is very expensive. If they did not use a hardened steel nail, the chance of the nails missing the hole and bouncing off of the steel plate workpiece would be very great, which creates a very dangerous condition. Another problem is that such a hardened guide tip often breaks, causing down time and the cost to replace the broken tip, which is also expensive. And the last big problem with these tools is they have this hardened guide tip, which acts as an elaborate safety, that hangs down and gets in the way of the operators line-of-sight. There is a unique compact palm nailer, with a magazine that has the tip of the nail hanging out the nose of the tool, thereby enabling the nail to be placed directly into the hole of the steel plate workpiece. Such a small palm nailing tool is ideal for confined nailing situations but is not fast enough for the high-volume nailing requirements of certain areas of the country. The reason it is not fast enough is because a palm nailer is a multi-blow tool, such that the driver blade in the tool hits the head of the nail many times before the nail is driven all of the way into the workpiece.  
         [0010]     It is therefore desirable to have small single-blow tool that will fit into very small places, mainly between one foot floor joist and one foot rafters. It is also desirable to have a single-blow tool that does not use hardened nails or a hardened nail guide tip (elaborate safety), and which is safer than tools heretofore known.  
         [0011]     Another desired feature is to have a tool that does not have a safety mechanism hanging down in the line-of-sight between the user and the workpiece.  
       BRIEF SUMMARY OF THE INVENTION  
       [0012]     The present invention is a lightweight single-blow tool that is around 10″ tall or less, enabling it to be used in very small areas. The present invention, because of its novel design, has no safety on the nose of the tool and does not need a hardened nail guide tip for guiding the nail into the hole. The design of the present invention also enables the user to place the tip of the nail directly into the hole of the metal workpiece, making this one of the safest tools on the market. It also does not need a hardened guide tip or elaborate safety to guide the nail into the hole in the steel. This invention does not have a safety on the tip of the nose. It is however, a very safe tool. The tip of the nail also sticks out of the nose of the tool making it very easy for the operator to place it into the hole in the steel. The present invention has an upper nosepiece and a spring-loaded lower nosepiece, and the lower nosepiece reciprocatingly slides upward into the upper nosepiece, thereby creating a telescoping nose, with a biasing spring urging the lower nosepiece to be telescopingly extended from the upper nosepiece. A magazine full of nails is mounted to the lower nosepiece for mutual movement therewith, and a safety linkage mounted to the magazine, thereby having mutual movement with the lower nosepiece, is operably connected to an actuating trigger. When the lower nosepiece is reciprocated into the upper nosepiece as the tool is pressed onto the workpiece, the safety linkage allows the trigger to actuate a trigger valve that causes the nail to be driven into the workpiece. If the lower nosepiece is not reciprocated into the upper nosepiece, as happens when the tool is not pressed into the workpiece, the safety linkage prevents the trigger from actuating the nail-driving mechanism, creating a safe condition because nails cannot be fired due to the safety linkage&#39;s prevention of nail driving actuation. Because of this feature, the present invention does not need a safety device on the nose of the tool. This is a great benefit because the user is able to see the tip of the nose of the tool and is thus able to accurately place the tip of the nail into the hole of the metal workpiece, which results in a tool that is safer than heretofore known in the prior art. When the tool is pushed downward, the safety linkage that is mounted to the nail magazine is caused to travel upward at the same time, thereby lifting the trigger linkage and enabling the operator to pull the trigger and fire a nail. Because of these features, the present invention is light weight, small, easy to use, and solves all of the current problems associated with the other tools on the market. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0013]      FIG. 1  is a right side view of the present invention showing the tool in the not-ready-to-fire position in which the lower nosepiece is telescoped out from the upper nosepiece.  
         [0014]      FIG. 2  is a right side view of the present invention similar to  FIG. 1 , but showing the tool in the ready-to-fire position in which the lower nosepiece is pressed against the workpiece and thus moved upwardly into the upper nosepiece.  
         [0015]      FIG. 3  is a left side view of the present invention showing the tool in the not-ready-to-fire position, with a portion of the tool body cut away to schematically show the movement of the driving piston.  
         [0016]      FIG. 4  is a schematic view of significant parts of the present invention shown in the not-ready-to-fire position in which the lower nosepiece is telescoped out from the upper nosepiece, and showing how the safety linkage prohibits the trigger from actuating the trigger valve.  
         [0017]      FIG. 5  is a schematic view of significant parts of the present invention shown in the ready-to-fire position in which the lower nosepiece is pressed against the workpiece and thus moved upwardly into the upper nosepiece, and showing how the safety linkage permits the trigger to actuate the trigger valve. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     Referring to  FIGS. 1 through 5  of the drawings, the structure of the present invention is shown. Some parts of the present invention are similar in structure to the prior art, and those parts will first be described, followed by a description of the improvements that are novel to the present invention.  
         [0019]     Pneumatic nailing tool  20 , like other prior art pneumatic nailing tools, has a body  22  which houses a vertically-reciprocating piston  24  having a circumferential O-ring  26 . An axially-disposed nail-driving shaft  28  extends downwardly from piston  24  to engage the head  30  of the leading nail  32  in the nail magazine  34 , and piston  24  is caused to move rapidly downward when a poppet valve (not shown) in the head  36  of tool body  22  causes compressed air to flow from a well-known air supply provided at nipple  38 . A well-known spring-loaded pusher  40  is mounted for longitudinal reciprocation within magazine  34 , and pusher  40  is pulled toward the tip  42  of tool  20  by a pusher spring  44 , thereby causing a sequence of nails within magazine  34  to be supplied to tip  42  for driving into a workpiece W. A trigger valve  46  is provided that, when actuated by trigger  48 , causes the poppet valve to release air from the air supply into the piston chamber  50 , thereby causing piston  24  to move rapidly downward, as shown in dotted outline as  24 ′ in  FIG. 3 , and drive the leading nail  32  into the workpiece W. This much is well-known in the prior art.  
         [0020]     The improvement of the present invention can now be described in detail. A lower nosepiece  52  is mounted for telescoping reciprocation within an upper nosepiece  54 , and magazine  34  is fixedly mounted to lower nosepiece  52  for joint movement therewith. The rear of magazine  34  is slidingly mounted, as by a bolt  55  on the rear of tool handle  60 , within an oblong slot  56  of a bracket  58  mounted to magazine  34  such that the rear of magazine  34  is allowed to reciprocate up and down with respect to handle  60  as bolt  55  moves within slot  56  as magazine  34  jointly moves up and down with lower nosepiece  52 . A coiled compression spring  62  engages lower nosepiece  52  and biases lower nosepiece  52  to be telescoped outwardly, and thus downwardly, from within upper nosepiece  54 . It should be understood that coiled compression spring  62  may be placed inside upper nosepiece  54  and in contact with the top of lower nosepiece  52 , as shown in  FIGS. 4 and 5 , or alternately and equivalently may be placed below upper nosepiece  54  and in contact with a flange on lower nosepiece  52 , as shown in  FIGS. 1-3 ; the essential function performed by spring  62  is to bias lower nosepiece  52  to telescope outwardly and downwardly from upper nosepiece  54  so that, when the tool is lifted from the workpiece W, lower nosepiece  52  will telescope out and away from upper nosepiece  54 . Axially-disposed nail-driving shaft  28  passes axially through upper nosepiece  54  and lower nosepiece  52  and contacts the head  30  of the leading nail  32 . Upper nosepiece  54  is fixedly mounted to body  22  of tool  20 , so that lower nosepiece  52  reciprocates with respect to body  22  as the lower nosepiece is pressed against the workpiece W for nailing.  
         [0021]     Mounted to magazine  34 , and thus moving jointly with lower nosepiece  52 , is a safety linkage  64  that is operably connected to actuating trigger  48  in a manner that will now be described in detail. Trigger  48  is mounted for angular movement with respect to body  22  about a first pivot  66  that is attached to body  22 , from an un-actuated position to an actuated position. A trigger lever  68  is provided within trigger  48 , and trigger lever  68  is, in turn, mounted for angular movement with respect to trigger  48  about a second pivot  70  that is attached to trigger  48 . Referring to  FIGS. 4 and 5 , which show safety linkage  64  in a somewhat-exaggerated schematic depiction for the purposes of explanation of the operative structure of the present invention, it can be seen that when lower nosepiece  52  is not pressed against the workpiece, as shown in  FIG. 4 , when the tool is in the “not-ready-to-fire” position, safety linkage  64  does not engagingly urge a distal portion  69  of lever  68 , remote from second pivot  70  of trigger lever  68 , upwardly, thereby preventing trigger lever  68  from engaging the pin  72  of trigger valve  46  as trigger  48  pivots about first pivot  66  from the un-actuated position to the actuated position. However, when lower nosepiece  52  is pressed against the workpiece W, as shown in  FIG. 5 , when the tool is in the “ready-to-fire” position, safety linkage  64 , because of the upward reciprocation of lower nosepiece  52  and magazine  34  with respect to body  22 , engages the distal portion  69  of trigger lever  68  and urges the distal portion  69  of trigger lever  68  upwardly so that, as trigger  48  pivots about first pivot  66 , trigger lever  68  engages and actuates the pin  72  of trigger valve  46  intermediate distal portion  69  and second pivot  70 . Thus it is seen that, when the lower nosepiece  52  is depressed against the workpiece W so that the tool is in the “ready to fire” position, then and only then trigger  48  is permitted to actuate trigger valve  46 , which, in turn, actuates the poppet valve in the head  36  of tool body  22 , thereby causing piston  24  to move rapidly downward and drive the leading nail  32  into the workpiece W. A safety mechanism is thus provided in accordance with the present invention that prevents firing of the nail unless the lower nosepiece is pressed firmly against the workpiece W, and, in contrast to the prior art, the safety mechanism of the present invention does not block the operator&#39;s view of the nail entering the workpiece W.  
         [0022]     The usage and firing of the tool will again be explained now that the details of the structure of the invention have been explained. The tool  22  is hooked to a well-known air source such as an air compressor by attaching an air hose between the air source and nipple  38 . Referring to FIGS. I and  4 , showing the tool not ready to be fired, the tip of the nail  32  can be seen, and this tip is placed into a hole in the steel strap workpiece W. Trigger lever  68  is in the down position, as is the safety linkage  64 . When these parts  64 ,  68  are in this position, the tool will not fire even it the trigger  48  is pulled upward. Referring to  FIGS. 2 and 5 , showing the tool in the position ready to be fired, both the safety linkage  64  and the trigger lever  68  are in the up position. When they are in this position, the trigger  48  can be pulled up to the actuated position and the tool will then fire. The following is a description of how the tool is fired. First, as already mentioned, the tip of the leading nail  32  is placed into the hole of the steel plate workpiece W. The operator then pushes down on the handle of the pneumatic tool. When the handle of the tool is pushed down, the upper nosepiece  54  begins to travel downward with respect to the lower nosepiece  52 , the safety linkage  64  begins to travel upward at the same time the spring  62  is compressed. Handle  60  also travels to the bottom of its stroke at the same time as bolt  55  slides within oblong slot  56  of bracket  58 . As this is all happening, the safety linkage  64  travels to the top of its stroke and causes the trigger lever  68  to be raised, thereby enabling pin  72  of trigger valve  46  to be actuated as trigger  48  is pulled to the actuated position, the tool is fired, and a nail is driven into the workpiece W.  
         [0023]      FIGS. 1 and 4  show the trigger  48  and the trigger lever  68  in the position where, if the trigger is pulled upward toward the pneumatic tool to the actuated position, the tool would not fire.  
         [0024]     The unique quality of this tool is there is no need of a cumbersome safety mechanism on the nose of the tool although the tool operates just as if one were present. No vision-obstructing safety mechanism is required on the nose of the tool, in contrast to the prior art.  
         [0025]     As heretofore described, the tool has a lower nosepiece  52 , which is attached to the magazine  34 , and the lower nosepiece  52  travels up and down allowing the tool to be fired. This is unique to a single-blow tool.  
         [0026]     The tool  20  preferably has the safety linkage bolted to the top of the magazine and operates in conjunction with the lower nosepiece and magazine.  
         [0027]     Another very important quality is this tool does not need to have a hardened nail. This is because the tip of the nail is placed directly into the hole of the steel workpiece, which makes for a very safe tool. Because there is no safety mechanism hanging down on the front of the nose of this tool, in contrast to the prior art, the operator is able to see exactly where the tip of the nail is being placed.  
         [0028]     Significant features of the present invention are thus understood to be: 
        1) No safety linkage on the nose of the tool.     2) The tool has a lower nosepiece and an upper nosepiece. The lower nosepiece is connected to the magazine and the magazine and lower nosepiece move up and down together.     3) The safety linkage that the tool does have is attached to the top of the magazine and travels up and down when the lower nosepiece and magazine travel up and down.        
 
         [0032]     Although the present invention has been described and illustrated with respect to a preferred embodiment and a preferred use therefor, it is not to be so limited since modifications and changes can be made therein which are within the full intended scope of the invention.