Patent Publication Number: US-10780567-B2

Title: Accessory attachment for driven fastener hand tool

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. § 119(e) of the following U.S. provisional patent application, which is incorporated by reference herein: 
     U.S. Provisional Patent Application No. 62/406,356, filed Oct. 10, 2016, and entitled “NOSE GUIDE FOR DRIVEN FASTENER HAND TOOL,” by Wong et al. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to driven fastener hand tools. Particularly, this invention relates to accessory attachment for driven fastener hand tools. 
     2. Description of the Related Art 
     Powered fastener driving tools, e.g. nail guns, have existed for decades. Perhaps not coincidentally, the first commercial nail gun was introduced in 1950 after World War II wherein the technology for rapidly firing projectiles was greatly advanced. The first nail guns were pneumatic, driven by compressed air. Although pneumatic power is still the most prevalent, over time fastener driving tools have been developed using other means of power, such as electric motors, solonoids, combustibles, e.g gas or explosive powder, have also been developed. Some development of technology related to powered fastener drivers, and particularly combustion driven fastener tools has occurred. However, there is still much need for further development. 
     Beyond the tool itself, there are various supporting devices that may assist in the operation of driven fastener hand tools. For example, a guide device can assist a user with proper positioning of the delivered fastener such that the driven fastener hand tool can be operated more quickly but still with precise placement of the fasteners. Positioning guides for driven fastener hand tools have been previously developed to locate the fastener position relative to feature having a fixed relationship to the fastener deliver point. However, previous guides for have been cumbersome and bulky, often being affixed to the driven fastener hand tool. 
     For example, U.S. Pat. No. 7,344,057, issued Mar. 18, 2008, by Dion et al. discloses a nailer comprises a main body, an elongated nail ejection channel in the main body for receiving a nail to be ejected and including a nail outlet leading out of the main body, and a plunger carried within and movable along, the nail ejection channel. The nailer also includes an actuator capable of moving the plunger along an ejection axis in the nail ejection channel for selectively ejecting the nail out through the nail outlet. A first guide member is carried by and movable relative to the main body, for engaging a first reference surface outboard of the nailer, and a first adjuster mechanism capable of adjusting the position of the first guide member relative to the main body is also provided. The position of the nail ejection channel can be adjusted relative to the first reference surface with the first adjuster mechanism when the nailer engages the first reference surface with the first guide member. 
     Guides for a driven fastener hand tool have also been developed employing a specially formed contact tip. U.S. Pat. No. 8,627,991, issued Jan. 14, 2014, by Francis et al. and U.S. Pat. No. 8,387,846, issued Mar. 5, 2013, by Francis et al. both disclose a blind guide work contact tip for mounting to a drive probe of a fastening tool is shaped in a manner which allows for an angled nail placement, such as 45 degree into a workpiece. The blind guide work contact is a one-piece attachment which is fitted around the existing drive probe and includes a body and two wings which extend therefrom forming a channel through which a fastener passes into the workpiece. The body has a work surface with a peak and sloped slides adjacent each side of the peak at approximately 45 degrees. The sloped surfaces allows the blind guide work contact tip to better access corners and angled spaces than previous work contact tips. The work contact tip also has a flat portion at the peak of the work surface so as to not inhibit face nailing. 
     In view of the foregoing, there is a need in the art for accessory support attachments for driven fastener hand tools. There is a need for such attachments to be simple, removable, and inexpensive. There is also a need for such attachments to be readily adaptable to a range of driven fastener hand tools, capable of being retrofitted to existing driven fastener hand tools. Particularly, there is a need for such accessory attachments for driven fastener hand tools to support a fastener position guide. In addition, there is a need for such accessory attachments to support a range of accessories for use with driven fastener hand tools. These and other needs are met by the present invention as detailed hereafter. 
     SUMMARY OF THE INVENTION 
     An accessory attachment for a driven fastener hand tool is disclosed comprising a mounting block having an attachment channel and an indexing guide feature. A plate for covering a fastener driving channel of the fastener tool has a nose end with chamfered edges on opposing sides towards the fastener driving channel and the attachment channel has opposing lips for seating against the chamfered edges of the nose end of the plate. One or more bolts through the mounting block at a bottom of the attachment channel press the nose end of the plate causing the opposing lips of the mounting block to press against the chamfered edges thereby securing the mounting block to the nose end of the plate. Alternately or additionally, the mounting block can be used to support a range of accessories including a non-marring pad, a light, such as an LED, a level, and/or an edge guide. 
     A typical embodiment of the invention comprises an accessory attachment for a driven fastener hand tool, including a mounting block having an attachment channel, the attachment channel having opposing lips for seating against chamfered edges of a nose end of a plate, the plate for covering a fastener driving channel of the driven fastener tool and having the nose end with the chamfered edges on opposing sides towards the fastener driving channel, and one or more mounting block fasteners disposed through the mounting block at a bottom of the attachment channel to press the nose end of the plate causing the opposing lips of the mounting block to press against the chamfered edges of the nose end of the plate thereby securing the mounting block to the nose end of the plate. 
     In some embodiments of the invention, the chamfered edges engagement with the opposing lips can fix the position of the mounting block along a length of the plate. The attachment channel of the mounting block can have sufficient depth to allow the opposing lips of the the mounting block to pass over a width of the nose end of the plate. Typically, the one or more mounting block fasteners can comprise threaded fasteners, such as bolts or screws. 
     In some embodiments of the invention, a guide feature can be affixed to the mounting block. The guide feature can comprises an edge guide. Alternately, the guide feature can comprise a horizontal post for locating a hole of a shelf support post relative to a fastener location aligned with the fastener driving channel. 
     In further embodiments of the invention, a non-marring pad is attached to the mounting block. The non-marring pad can comprise a disc shape over a cupped end of the mounting block. 
     In other embodiments of the invention, a light assembly or a level can be attached to the mounting block. The light assembly can employ an LED light. The level can be configured with a view port in the side or end of a cylinder for aligning fasteners horizonally or vertically, respectively. The mounting block can comprise a cylindrical opening which can support either a light assembly or a level. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings in which like reference numbers represent corresponding parts throughout: 
         FIGS. 1A and 1B  show an example embodiment of the invention for attaching to a nose of a driven fastener hand tool; 
         FIGS. 2A and 2B  show an example embodiment of the invention for attaching to a nose of a driven fastener hand tool including a non-marring pad; 
         FIGS. 2C and 2D  show an example embodiment of the invention for attaching to a nose of a driven fastener hand tool including a light, such as an LED; 
         FIGS. 2E and 2F  show an example embodiment of the invention for attaching to a nose of a driven fastener hand tool including a level; 
         FIGS. 2G and 2H  show an example embodiment of the invention for attaching to a nose of a driven fastener hand tool including an edge guide; 
         FIG. 3  shows an example embodiment of the invention in use to locate fastener holes in a pilaster; and 
         FIGS. 4A to 4D  show different views of an example embodiment of the invention attached to the nose end of the channel covering plate for a driven fastener hand tool. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     1. Overview 
     As previously mentioned, embodiments of the invention comprise an accessory attachment for a driven fastener band tool. A majority of driven fastener hand tools (regardless of the power source) employ a nose plate at the front of the hand tool which covers the fastener driving channel. Like the barrel of a gun, the fastener driving channel is where the next fastener is positioned to be driven from the fastener clip by the driver (or blade). The nose plate is conveniently removable to allow a user to clear any fasteners if a jam should occur. Embodiments of the invention can be directed to a mounting block which is conveniently attached to the nose plate of a driven fastener hand tool. 
     A plate for covering a fastener driving channel of the fastener tool has a nose end with chamfered edges on opposing sides towards the fastener driving channel and the attachment channel has opposing lips for seating against the chamfered edges of the nose end of the plate. One or more bolts through the mounting block at a bottom of the attachment channel press the nose end of the plate causing the opposing lips of the mounting block to press against the chamfered edges thereby securing the mounting block to the nose end of the plate. 
     Embodiments of the invention can be implemented with any suitable driven fastener hand tool which may fire any type of fastener, e.g. staple, brad, nail, etc., and using any known type of driving power, e.g. compressed air, combustion, electric, etc., as will be understood by those skilled in the art. 
     In one notable example, the accessory attachment supports an indexing fastener position guide for a driven fastener hand tool. The indexing fastener position guide is affixed directly to the nose of the driven fastener hand tool and provides a guide feature located in precise relationship with the entry point of the fastener from the nose of the hand tool. The relative relationship between the guide feature and the fastener entry point is designed to match a specific application. 
     The described novel system for attachment to any suitable driven fastener hand tool can be used for a mounting block which includes an indexing guide feature for easy alignment of the proper position of the fasteners delivered by the hand tool in use. However, the mounting block can additionally or alternately be used to support a range of possible accessories as well. For example, such alternate accessories include, without limitation, a non-marring pad, a light, such as an LED, a level, and/or an edge guide. 
     2. Exemplary Driven Fastener Hand Tool Accessory Mounting Block 
       FIGS. 1A and 1B  show an example embodiment of the invention attached to a nose  102  of a driven fastener hand tool  100  including an indexing guide.  FIG. 1A  shows the mounting block  106  attached to the nose plate  104  of the driven fastener hand tool  100  near the entry point of the fastener from the nose of the hand tool  100 . The nose plate  104  has an end with chamfered edges  110 A,  110 B on opposing sides towards the fastener driving channel (shown in  FIG. 1B ). The mounting block  106  includes an attachment channel  114  which has opposing lips  112 A,  112 B at the top edges of the attachment channel  114 . These opposing lips  112 A,  112 B seat against the chamfered edges  110 A,  110 B of the nose end  102  of the plate  104 . The opposing lips  112 A,  112 B are separated from each other by a distance shorter than the width of the nose end  102  of the plate  104 . One or more mounting block fasteners  116  (e.g. bolts) are disposed through the mounting block  106  at a bottom of the attachment channel  114  to press against the top surface of the nose end  102  of the plate  104  causing the opposing lips  112 A,  112 B of the mounting block  106  to press against the respective chamfered edges  110 A,  110 B of the nose end  102  of the plate  104  thereby securing the mounting block  106  to the nose end  102  of the plate  104 . 
       FIG. 1B  shows the mounting block  106  attached to the nose plate  104  and fasteners  116  in an exploded view. Mounting block fasteners  116  (typically bolts or set screws) are shown schematically as cylinders which match cylindrical through holes in the mounting block  106 . If threaded elements (such as bolts or set screws) are employed as the mounting block fasteners  116 , the mounting block  106  will have threaded through holes in the bottom of the attachment channel  114 . The fasteners  116  are then threaded into the threaded through holes of the mounting block  106  and screwed down such that, when the mounting block  106  is properly positioned over the nose end of the nose plate  104 , the ends of the fasteners  116  press against the top surface of the nose end  102  of the plate  104  and force the channel  114  away from the top surface of the nose plate  104 . This force causes the opposing lips  112 A,  112 B of the mounting block  106  to engage the chamfered edges  110 A,  110 B of the nose end  102  of the plate  104  and thereby secure the mounting block  106  in place onto the nose end  102  of the plate  104 . 
     It should be noted that the attachment channel  114  of the mounting block  106  can be made with sufficient depth to allow the opposing lips  112 A,  112 B of the mounting block  106  to pass over the width of the nose end  102  of the plate  104  (either slipping the mounting block  106  on from the end or hooking one side first with the mounting block  106  canted relative to the plate  104 ). 
     The opposing lips  112 A,  112 B seating against the chamfered edges  110 A,  110 B of the nose plate  104  secure the mounting block  106  to the nose plate  104 . Because the chamfered edges  110 A,  110 B of the nose plate  104  have a length matching the length of the opposing lips  112 A,  112 B, the mounting block  106  is secured in a specific vertical location along the nose plate  104 . Once secured in place, the mounting block  106  does not slide along the nose plate  104 . Additional matching features can also be applied to the opposing lips  112 A,  112 B and chamfered edges  110 A,  110 B, e.g. one or more grooves and ridges on the opposing lips  112 A,  112 B and matching one or more ridges or grooves on the chamfered edges  110 A,  110 B, to lock the mounting block  106  to the nose plate  104  in a fixed vertical position when the fasteners  116  are engaged to press these two elements together. The rigid form of the mounting block and fixed dimensions of the opposing lips  112 A,  112 B with chamfered edges  110 A,  110 B of the nose plate  104  also lock the mounting block  106  to the nose plate in a fixed horizontal position when the fasteners  116  are engaged. Accordingly, both the vertical and horizontal positions of the mounting block relative to the entry point of the fastener from the nose of the hand tool  100  is precisely controlled by the design of this interface. This precise positioning of the mounting block  106  relative to the entry point of the fastener from the nose of the hand tool  100  enables a range of accessories to be supported by the mounting block  106  to enhance operation of the hand tool  100 . 
     The mounting block  106  can typically be formed from any suitable metal such as aluminum or steel and any alloy. Alternately, the mounting block  106  can be produced from strong, durable plastic or other synthetic materials. In addition, those skilled in the art will appreciate that the mounting block  106  can also be constructed as an assembly of components employing different materials. In one example, the mounting block  106  can be produced from a raw extruded aluminum component which undergoes finish machining of key elements, e.g., threaded holes, or other attachment features and any other application-specific elements (e.g. a guide feature). 
     In one primary example application, the mounting block  106  can support an indexing guide comprising a guide feature  108  which locates the proper position of the fasteners delivered by the hand tool in use. The guide feature  108  shape and position on the mounting block  106  is typically designed for a specific application. It can have any necessary shape for a particular application. However, in many cases, the guide feature  108  can be configured as a post vertically aligned with the delivered fasteners. The size and shape of the guide feature  108  as a post can be made to match a particular hole for a particular application. Typically, the leading edges of the guide feature  108  post will be tapered to better facilitate quick insertion into the indexing hole. Suitable applications for a guide according to the present invention will have a desired fastener location very near another hole or feature (such as an edge) on the workpiece in a repeating manner. 
     3. Exemplary Accessories for Mounting Block 
     It is important to note that the novel attachment of the mounting block  106  employing opposing lips  112 A,  112 B seating against the chamfered edges  110 A,  110 B of the nose plate  104  can be applied to other suitable accessories as well. For example, a light, e.g. an LED light, can be attached to the nose plate  104  in a similar manner. Other such accessories can be attached in the same position as the mounting block  106  shown or at alternate elevations along the nose plate  104  employing the same attachment device. Typically, a standard set of chamfered edges  110 A,  110 B on the nose plate  104  can be used to attach different mounting blocks for different accessories such as described hereafter. Furthermore, the mounting block  106  or other accessories can also be attached at different angles in fixed or adjustable positions. A mounting block  106  can be attached with a guide feature  108  vertically, at a fixed angle or at an adjustable position and/or angle. Having the guide feature  108  at an angle allows a user to shoot the staples at an angle relative to a reference on or near the work piece against which the guide feature  108  is rested. 
       FIGS. 2A and 2B  show an example embodiment of the invention for attaching to a nose of a driven fastener hand tool including a non-marring pad  202 .  FIG. 2A  shows the mounting block  210  attached to the nose plate  104  of the driven fastener hand tool  100  and  FIG. 2B  shows the mounting block  210 , fasteners  116 , and non-marring pad  202  in an exploded view. Attachment of the mounting block  210  to the nose plate  104  is identical to the attachment of mounting block  106  described above in  FIG. 1B , employing mounting block fasteners  116 , opposing lips  112 A,  112 B on the mounting block  106  seating against the chamfered edges  110 A,  110 B of the nose plate  104 . However, in this case the mounting block  210  is configured to support a non-marring pad  202 . The mounting block  210  comprises a cupped end  204  having a through hole  206  for the fastener entry point from the hand tool  100 . The through hole  206  aligns with a pad through hole  208  when the non-marring pad  202  is installed over the end  204  of the mounting block  210 . Those skilled in the art will appreciate that the non-marring pad  202  can be formed into any useful shape. 
     In the example shown, the pad  202  comprises a disc shape covering the cupped end  204  of the mounting block  210 . Those skilled in the art will understand that the non-marring pad  202  can be configured to have any useful shape for various applications. For example, the non-marring pad  202  can be configured to have a conical or pyramid shape with the through hole  208  at the point or a prismatic shape with the through hole  208  along a leading edge. The shape of the non-marring pad  202  can be designed to match the surrounding area of the desired fastener placement for a particular application. Accordingly, differently shaped non-marring pads can be interchangeably used with the mounting block  210 . 
     The non-marring pad  202  can be attached to the mounting block  210  by forming the mounting block  210  and the pad  202  to have interlocking features that can be snapped into coupling or press fit together such that the pad  202  is secured to the block  210  and will not be knocked loose from all but very extreme impacts. For example, a groove can be formed around the inner concave feature in the pad  202  and a matching beading can be formed around the mating perimeter of the mounting block  210 . Those skilled in the art will appreciate that many alternate types of snap or press mounting can be employed between the mounting block  210  and the pad  202  depending upon the selected materials of each component. This interface will be identical for differently shaped pads  202  which can be interchangeably employed as described above. 
     When the mounting block  210  with the non-marring pad  202  is installed, the pad  202  covers the delivery end of the driven fastener hand tool  100  so that the tool can be quickly moved from one position to another without marking or damaging finished surfaces of the workpiece. The non-marring pad  202  can be constructed of any suitable durable non-marring material. Any known suitable plastic, rubber, nylon, or other synthetic material can be used. In one notable example, the non-marring pad  202  can be manufactured from a slick, smooth, and durable material, e.g. polyethylene, such as UHMW polyethylene. 
       FIGS. 2C and 2D  show an example embodiment of the invention attached to a nose of a driven fastener hand tool including a light assembly  214 .  FIG. 2C  shows the mounting block  212  attached to the nose plate  104  of the driven fastener hand tool  100  and  FIG. 2D  shows the mounting block  212 , fasteners  116 , and light assembly  214  in an exploded view. Attachment of the mounting block  212  to the nose plate  104  is identical to the attachment of mounting block  106  described above in  FIG. 1B , employing mounting block fasteners  116 , opposing lips  112 A,  112 B on the mounting block  212  seating against the chamfered edges  110 A,  110 B of the nose plate  104 . 
     The mounting block  212  for this accessory includes a vertical cylindrical opening  216  accessed from the top end with a smaller through hole at the bottom end to support the light assembly  214 . The light assembly  214  comprises a light board  218 , one or more batteries  220  and a cap assembly  226  which are all installed in order within the cylindrical opening  216  in use. 
     The light board  218  includes the electrical light mounted on a supporting board and which matches the inner diameter of the cylindrical opening  216 . Any known suitable electrically powered light can be used. Color and brightness of the light can be varied. For example, the light can comprise an LED (light emitting diode) because such lights are energy efficient and can be very bright. When installed in the cylindrical opening  216 , the light on the light board  218  is exposed though the smaller through hole at the bottom end such that it can deliver a light beam  224  to shine onto the work area when the tool  100  is in use. 
     One or more batteries  220 , e.g. any suitable small watch batteries, are stacked on top of the light board  218  to make electrical contact with the light on the board and with each other. The light assembly  214  is then closed out with a cap assembly  226  which includes a top contact for the batteries as well as an switch, e.g. a push button on/off switch. The cap assembly  226  can be either threaded into the cylindrical opening or formed with any known suitable snap fit interface for replacement of the batteries as needed. The electrical circuit from the cap assembly  226  to the light board  218  can be closed either though use of an electrically conductive mounting block  212  which contacts both components or a separate wire or conductive strap running from the light board  218  to the cap assembly  226  within the cylindrical opening  216  along side the one or more batteries  220 . 
     In order to access the fasteners  116  which attach the mounting block  212  to the nose plate  104 , through holes  222  are made from the outside of the cylindrical opening  216  and aligned with the threaded holes  228 . The threaded holes  228  support the fasteners  116  when the mounting block  212  is attached to the nose plate  104 . 
       FIGS. 2E and 2F  show an example embodiment of the invention attached to a nose of a driven fastener hand tool including a level  230 .  FIG. 2E  shows the mounting block  232  attached to the nose plate  104  of the driven fastener hand tool  100  and  FIG. 2F  shows the mounting block  232 , fasteners  116 , and level  230  in an exploded view. Attachment of the mounting block  232  to the nose plate  104  is identical to the attachment of mounting block  106  described above in  FIG. 1B , employing mounting block fasteners  116 , opposing lips  112 A,  112 B on the mounting block  106  seating against the chamfered edges  110 A,  110 B, of the nose plate  104 . This mounting block  232  is similar to the mounting block  212  for the light of  FIGS. 2C and 2D  above because the mounting block  232  also includes a vertical cylindrical opening  234 . However, the cylindrical opening  234  here also includes a slotted side  236  which allows a user to view a port  238 A in the side of the level  230 . 
     The level  230  functions as known levels using a bubble in a trapped liquid visible though a transparent view port  238 A. The bubble  2 - 38 A moves as the cylindrical level  230  is tilted transverse to the axis of the cylinder. A “level” reading is indicated when the bubble is trapped in a high spot of the view port  238 A and can be seen within precise markings on the transparent view port  238 A. Since alignment of the level  230  is critical, the cylindrical opening  234  and level  230  can incorporate a matching key and keyway features on their surfaces to ensure that the level  230  is precisely aligned when installed. The cylindrical opening  234  and level  230  can also include a snap fit interface to secure the level  230  when installed. The port  238 A as configured will allow a user to repeatedly apply fasteners precisely horizontal to the ground. 
     In another configuration, an alternate (or additional) view port  238 B can be employed at the cylindrical end of the level  230  (shown with a dashed line). A view port  238 B in this location will allow a user to level the tool  100  such that fasteners are delivered vertically (aligned in two dimensions). 
     Similar to the light assembly  214  of  FIGS. 2C and 2D , in order to access the fasteners  116  which attach the mounting block  232  to the nose plate  104 , through holes  240  are made from the outside of the cylindrical opening  216  and aligned with the threaded holes  228 . The threaded holes  228  support the fasteners  116  when the mounting block  212  is attached to the nose plate  104 . 
     Referring again back to the light assembly  214  embodiment of  FIGS. 2C and 2D , the light assembly  214  including the light board  218 , one or more batteries  220  and a cap assembly  226  can all be implemented within a separate closed cylindrical housing the same size and shape as the level  230 . In this configuration, the light assembly  214  and level  230  can be interchangeably employed with the mounting block  232 . The only additional element is a small through hole at the bottom of the cylindrical opening  234  for the light of the light assembly to shine through. 
       FIGS. 2G and 2H  show an example embodiment of the invention attached to a nose of a driven fastener hand tool including an edge guide  242 . It should be noted that the edge guide  242  is a specific type of guide feature  108  which has been generally described above regarding  FIGS. 1A and 1B  (and hereafter regarding  FIGS. 3 and 4A to 4D ).  FIG. 2G  shows the mounting block  244  attached to the nose plate  104  of the driven fastener hand tool  100  in use and  FIG. 2H  shows the mounting block  244  and fasteners  116  in an exploded view. Attachment of the mounting block  244  to the nose plate  104  is identical to the attachment of mounting block  106  described above in  FIG. 1B , employing mounting block fasteners  116 , opposing lips  112 A,  112 B on the mounting block  106  seating against the chamfered edges  110 A,  110 B of the nose plate  104 . The mounting block  244  includes an integral edge guide  242  which is configured to provide a flat surface a specific distance  248  from the fastener delivery point as shown. The flat surface of the edge guide  242  is also parallel to the delivered fasteners. 
     As shown in the  FIG. 2G , the edge guide  242  is held flush against a workpiece surface  246  so every fastener will be delivered at precisely the same distance  248  from the workpiece edge, i.e. from the surface  246 . In addition, holding the edge guide flush will ensure that each fastener is delivered parallel to the surface  246  as well. 
     The mounting block  244  including the edge guide  242  is application-specific. Thus, different edge guides  242  having different dimensions for different placement distance  248  can be produced. Typically, a set of different mounting blocks  244  can be produced having different distances in ¼ or ⅛ inch increments. 
     4. Exemplary Driven Fastener Hand Tool Hole Indexing Guide 
       FIG. 3  shows the example embodiment of the invention including a hole indexing guide in use to locate fastener holes  120  in a pilaster  122  for attaching wall mounted supports, such as shelf supports. In this example application, the guide is designed to facilitate precise location of staple fasteners in a pilaster or support post  122  typically vertically fastened to a wall. The support post  122  includes a repeating series of fastener holes  120  along its length. When the guide feature  108  is placed in a matching rectangular hole  118 , the entry point at the nose of the driven fastener hand tool is automatically precisely positioned to deliver a staple into two adjacent holes  120  nearby. Most driven fastener hand tools will also employ a safety pin  124  as shown which must be depressed against the workpiece before the fastener hand tool can be fired. 
     The use of a rectangular shaped guide feature  108  helps to ensure that the fastener position is also rotationally aligned as tool  100  cannot be rotated very far out of position without causing the feature  108  to bind in the matching rectangular hole  118 . 
     Those skilled in the art will appreciate that the novel attachment mechanism is compact and efficient and allows for different guides or other accessories to be employed in different applications. Different application-specific mounting blocks can be readily produced at a low cost. In addition, because most driven fastener hand tools employ a nose plate  104 , the guide can be implemented as a retrofit to such tools. Only a very minor modification to the nose plate is required, i.e. forming two chamfered edges  110 A,  110 B, to enable use with any application-specific mounting block. 
       FIGS. 4A to 4D  show different views of an example embodiment of the invention attached to the nose end of the channel covering plate  104  for a driven fastener hand tool  100 . The extra depth of the attachment channel  114  can be seen as a gap between the bottom of the channel  114  and the plate  104  in the end view shown above the section A-A view. The fastener  116  extends from the bottom of the channel  114  to press against the plate  104 . This pressing by the fastener(s)  116  causes the opposing lips  112 A,  112 B of the nose block  106  and chamfered edges  110 A,  110 B of the nose end  102  of the plate  104  to be forced together, securing the block  106  to the plate  102 . 
     This concludes the description including the preferred embodiments of the present invention. The foregoing description including the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible within the scope of the foregoing teachings. Additional variations of the present invention, may be devised without departing from the inventive concept as set forth in the following claims.