Abstract:
A guide bushing for a reciprocating nailer includes a body having a cylindrical portion and a tapered portion. An aperture extends through the body for receiving a driving rod. The tapered portion of the guide bushing extends from the nailer and is configured to fit into tight spaces, such as corners and along the tongues or grooves of, for instance, tongue and groove flooring, to fully support a nail as it is driven into the tight space. The guide bushing can be a multiple part or multiple stage bushing for more flexibility and utility. The aperture through the center of the bushing can also be stepped to cooperate with a stepped driving rod for closer holding of narrower nails. A boot can be placed at the tip of the guide bushing to provide a cushion and further retention of a nail held by the nailer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional patent application Ser. No. 61/081,062, filed Jul. 16, 2008 by the present inventor. 
    
    
     BACKGROUND 
     1. Field 
     This application relates to a compact, reciprocating, electrically or pneumatically operated impact tool, and specifically to an improved nail guide bushing mechanism for palm nailers. 
     2. Prior Art 
     The previously known mechanisms for power driving have been of substantial size and weight and dimensionally unsuited for operation in confined areas. Such mechanisms also have primarily incorporated the principle of a single stroke operation, controllable at the desire or will of an operator, and have not normally been adapted for use where relatively short repetitive strokes of a tool or operating mechanism are desirable. 
     Compact reciprocating impact tools, which are electrically or pneumatically operated (Hammerhead auto hammer, palm nailer) have overcome the drawbacks in these previously mentioned mechanisms, and provide a device of relatively small dimension. Such tools are lightweight, comfortably usable in confined areas by an operator, and substantially reduce problems of manipulation and fatigue by the user. 
     These compact impact tools can be used in compact areas, but have neglected to address the issue of placing nails which require the impact to be located in compact places, such as the positioning of a nail within a recess that is not accessible by the prior art devices. In  FIG. 12  the prior art guide bushing or rod has maintained a large face compared to the size of the nail head which it guides. Therefore, if a nail must be located in a narrow channel or in the inside corner of a tongue and groove floor, the impact tool cannot nail in confined nail placement areas. 
     Developers of prior art products failed to address this problem because a mini palm nailer, for example, is designed for a broad use, up to 16d nails. Therefore the guide bushing must have a bore in the end large enough to receive the head of a 16d nail plus the perimeter of the bushing including the guide bushing material thickness plus room for a magnetic holder leaving a large diameter at the end of the guide bushing. Prior-art nailers are generally designed for nail placement on flat surfaces. 
     SUMMARY 
     A guide bushing with a conical or tapered distal end which can be round, flat, or tapered at the distal end of the guide bushing. The guide bushing is modified for a variety of fasteners. A second guide bushing can be used for additional support. The guide bushing has a peripheral collar and is slide mounted in a guide bushing securing collar. The guide bushing collar (a type of shoulder ) is adapted for engagement with a circular abutment formed in the interior bore of the securing collar to limit outward guide bushing movement when mount on a fastener-driving tool. A driver rod can be modified for a variety of fasteners. 
     One embodiment of this tool is  FIG. 13  a mini palm nailer with a driver rod slightly larger than a finish nail. The guide bushing is tapered with a bore to both guide the driver rod and the fastener. The taper allows the fastener to be driven in the tongue of a floor board while operating close to a wall as illustrated in  FIG. 15 . 
    
    
     
       DRAWINGS 
         FIG. 1  is an exploded perspective view of a palm nailer incorporating a tapered guide bushing according to the invention. 
         FIG. 2  is an enlarged perspective view of the tapered guide bushing of  FIG. 1 . 
         FIG. 3  is an enlarged perspective view of a driver of the palm nailer of  FIG. 1 . 
         FIG. 4  is an enlarged view of the tip of the tapered guide bushing which could be implemented in the embodiments of  FIGS. 1 and 5 , showing a circumferential groove for receiving a cushioned tip/boot. 
         FIG. 5  is an exploded perspective view of a palm nailer incorporating a tapered guide bushing and stepped driver according to a further embodiment of the invention. 
         FIG. 5A  is an enlarged exploded perspective view of a tapered guide bushing assembly of  FIG. 5 . 
         FIG. 6  is an enlarged perspective view of the tapered guide bushing of  FIGS. 5 and 5A . 
         FIG. 7  is an enlarged perspective view of a stepped driver of the palm nailer of  FIG. 5 . 
         FIG. 8  is a perspective view of a further guide bushing assembly embodiment including plural cooperating guide bushings. 
         FIG. 8A  is an exploded perspective view of the guide bushing assembly embodiment of  FIG. 8 . 
         FIG. 8B  is an exploded perspective view of a further guide bushing assembly embodiment including plural cooperating guide bushings. 
         FIG. 9  is an enlarged perspective view of a tapered guide bushing (with an apse tip, that is a rounded tip) according to a further embodiment of the invention. 
         FIG. 10  is an enlarged perspective view of a tapered guide bushing (with flat tip) according to a further embodiment of the invention. 
         FIG. 11  is an enlarged perspective view of a tapered guide bushing (with a wedged tip) according to a further embodiment of the invention. 
         FIG. 12  is a perspective view of a prior art palm nailer. 
         FIG. 13  is an enlarged perspective view of a palm nailer with a tapered guide bushing according to a further embodiment of the invention. 
         FIG. 14  is a perspective view of a prior art palm nailer positioned to drive a nail in a confined space and angled location and is unable to achieve the proper result of driving the nail essentially fully into the article. 
         FIG. 15  is a perspective view of a palm nailer according to the invention positioned to drive a nail in a confined space and angled location which is able to achieve the proper results of driving the nail essentially fully into the article. 
     
    
    
     DETAILED DESCRIPTION 
     First Embodiment—FIGS.  5 A and  5   
       FIGS. 5 and 5A  show a guide bushing  520  having a taper  522  to a sharp edge tip  526 . A magnet  528  is adhered in a perpendicular bore  530  to a guide bushing bore  524 . The guide bushing  520  has a stepped center bore  536  forming a shoulder  534  which is congruent in shape to a driver rod  570  with a shoulder  544 . The driver rod  570  is guided by the guide bushing bore  524 . The guide bushing  520  has a stepped bore  538  forming a spring seat  539 . The guide bushing  520  has a peripheral collar  532  (a type of shoulder). Guide bushing  520  is slide mounted into a removable guide bushing securing collar  560 . The collar  532  is adapted for engagement with a circular abutment  562  formed in the interior bore  564  of the securing collar  560 . 
     Referring again to  FIGS. 5 and 5A , driver rod  570  is threaded into a piston  572 .  FIG. 5  shows the piston  572  attached to the driver rod  570  showing a removable assembly  570  and  572 . Piston  572  is seated in a cylinder  573  which permits piston  572  to repeatedly reciprocate back and forth in short strokes to provide an intermittent force delivered by driver  570  to a fastener (e.g., nail  1408  or cleat  1154 ) in guide bushing bore  524  when pressurized air is supplied to the air inlet  575  from a pressurized air source and the tool is activated as is known in the art. Cylinder  573  including piston  570  seated therein is encased in both a lower housing  505  and upper housing  508  secured together with aligned screws  509 . Referring further to  FIGS. 5 and 5A , driver end  576  is inserted through a body bore  510 , a spacing washer  504 , the spring  540 , the guide sleeve  520 , the guide bushing bore  526 , and the securing collar bore  560 . A prior art guide bushing  502  is shown. 
     These specifics are what I presently prefer for this embodiment and I presently contemplate that the guide bushing  520  of the embodiment of  FIG. 5A  may have a circular cross section with a circular bore  524  and be made of 4041 steel. However this embodiment can have different cross sections, such as oval, triangular, rectangular, square, hexagonal, etc. and different shaped guide bushing with varying bores, with drive rods of varying sizes and shape for a variety of fasteners. These can be made of materials such as austenitic steel, high carbon steel, magnetized steel, titanium, polycarbonates, etc. With the embodiment of  FIG. 5A  and others it will be important to provide a choice of driver rod assemblies, an assortment of guide bushings, springs, securing collars and tools to disassemble and assemble. 
     Operation 
       FIG. 5A  shows an exploded perspective view of one embodiment of a tapered guide bushing assembly including a driver rod  570  which is positioned with the guide bushing  520 . Guide bushing  520  is retractable upon contact with the fastener-receiving member (i.e., a hardwood floor board  1502  or other article) into which the fastener is being driven. The guide bushing  520  has a taper  522  which intersects a guide bushing bore  524  at a sharp edge tip  526 . A magnet  528 , which holds a fastener, is adhered in a bore  530  perpendicular to the guide bore  524 . The guide bore  524  has a stepped bore  536  which guides a driver rod  570  which also has a stepped shoulder  544  to match the bore shoulder  534 . 
     As illustrated in  FIG. 5 , the lower assembly consists of a removable guide bushing securing collar  560  which joins the guide bushing  520  with a mating guide bushing peripheral collar  532 . Guide bushing  520  is slide mounted into the securing collar  560 . The collar  532  is adapted for engagement with a circular abutment  562  formed in a interior bore  564  of the securing collar  560 . The securing collar  560  secures the tapered guide bushing assembly illustrated in  FIG. 5A  by threading into the body threads  514  illustrated in  FIG. 5 . The driver rod  570  is threaded into a piston  572  forming a removable driver rod assembly  570  and  572 . The piston  572  is seated in a cylinder  573  which is encased in both a lower housing  505  and upper housing  508  secured together with aligned screws  509  as is known in the art. Piston  572  repeatedly reciprocates back and forth in short strokes in cylinder  573  to provide an intermittent force delivered by rod  570  to a fastener (e.g., nail  1408  or cleat  1154 ) in guide bushing  520  when pressurized air enters air inlet  575  from pressurized air source and the tool is activated. The intermittent force is used to drive the fastener supported by an inventive guide bushing  520  essentially fully into an article such as the tongue-and-grove flooring board  1502  illustrated in  FIG. 15 . 
     A driver end  576  is inserted through body bore  510 , a spacing washer  504 , the spring  540 , the guide bushing bore  524 , and the securing collar bore  564 . As illustrated in  FIG. 5A , the top of the guide bushing  520  has a spring seat bore  538 , forming a spring seat shoulder  539  on which a spring  540  is mounted. Spring  540  contacts a spacing washer  504 . Washer  504  abuts body  512  as illustrated in the example of  FIG. 5 . The spring  540  forces the guide bushing  520  outward. The bushing bore  524  supports a fastener positioned therein. 
     As the operator applies force activating impact by the driver  570 , the spring  540  allows the guide bushing  520  to retract as the bushing  520  makes contact with the surface of the article into which the fastener is being driven. The guide bushing  520  guides and supports the fastener as it is driven into the surface of the article. 
     As illustrated in  FIG. 5A , the guide bushing  520  has a peripheral collar  532  and is slide mounted in the guide bushing securing collar  560 . The collar  532  is adapted for engagement with a circular abutment  562  formed in the interior bore  564  of the securing collar  560  at the lower end of an enlarged diameter portion of the bore  564 . The collar  560  and guide bushing  520  interact. The collar  560  serves as a guide for maintaining positive alignment of the driver  570  driving end  576  with a head of a fastener in the guide bushing  520  during impact, while also providing a positive limit stop which limits guide bushing  520  movement away from the lower housing  508 . 
     Application of force between a fastener (e.g. a nail  1408  or a cleat  1154 ) to be driven and the driver end  576  activates rapid reciprocating driver  570  impact until the fastener reaches its predetermined depth which deactivates impact. The depth to which the fastener (e.g., nail  1408  or cleat  1154 ) is driven is controlled by use of spacing washers  504  as shown in the example of  FIG. 5 . Use of relatively more spacing washers  504  or fewer spacing washers  504  allows the user to determine the desired depth by which to set the fastener. This embodiment enables the operator to drive a variety of fasteners in confined fastener-placement as illustrated in  FIG. 15  in addition to normal fastener-placement areas. 
       FIG. 8A  is an exploded perspective view of a guide bushing assembly including plural cooperating guide bushings with a stepped driver according to the further embodiment of the invention of  FIG. 8 . 
     Referring to  FIG. 8  and  FIG. 8A , there is shown a guide bushing assembly which consists of a guide bushing  842  in which driver rod  870  is positioned and a guide bushing  852  in which guide bushing  843  is positioned in a telescoping relationship. The guide bushing  842  retracts upon contact with the receiving member (e.g., the flooring board  1402 , 1502  or other article) into which the fastener (e.g., nail  1408  or cleat  1154 ) is being driven, to facilitate continued driving of the fastener to its proper depth. The guide bushing  842  includes a taper  846  ending in an apse  845  (i.e., a rounded end) which intersects a guide bushing bore  844 . 
     A magnet  841  is adhered in a bore  843  perpendicular to bore  844  and which intersects the guide bore  844 . The guide bushing  842  has a peripheral collar  848  (a type of shoulder) and is slide mounted into a larger first guide bushing  852  from the top. The peripheral collar  848  is adapted for engagement with a circular abutment  854  formed in a bore  856  of the guide bushing  852 . 
     A spring  850  is inserted into the bushing bore  856  on top of the guide bushing  842 . A threaded bore sleeve  851  is inserted into a threaded bore  858  of guide bushing  852 . Interaction between the sleeve  851  and guide bushing  842  serves as a guide for maintaining positive alignment of a driving end  874  of driver  870  with a head of a fastener (e.g., nail  1408  or cleat  1154 ) during impacting, while also providing positive limit stops. 
     The guide bushing  842  has an interior peripheral collar  847  congruent (i.e.,axially aligned) with a driver rod  870  and a driver rod shoulder  872 . The guide bushing  852  has a taper  822  which intersects the guide bore  853  at a sharp edged tip  855 . The guide bushing  852  has a peripheral collar  857  (a type of shoulder). The guide bushing  852  is slide mounted in a securing collar  860 . The collar  857  is adapted for engagement with a circular abutment  862  formed in a bore  864  of the securing collar  860 . Cooperative interaction between the guide bushings  842 ,  852  and between guide bushing  852  and collar  860  serves as a guide for maintaining positive alignment of the driving end  874  with a head of a fastener (e.g., nail  1408  or cleat  1154 ) during driving, while also providing positive limit stops. 
     A spring  840  has one end which contacts housing body  505  in the same manner as spring  540  illustrated in  FIG. 5 . Spring  840  has a second end which is fitted over neck  861  and contacts bushing shoulder  859 . Both springs  850  and  840  act independently and allow both guide bushings  842  and  852  to fully extend allowing the guide bushing  852  to support the guide bushing  842  which supports the fastener (e.g., nail  1408  or cleat  1154 ). Both the guide bushings  842  and  852  retract independently as the operator applies force while driving fasteners. The driver rod  870  narrows at the shoulder  872  to a smaller rod dimension  876  with the driver end  874 . 
     When force is applied between a fastener to be driven and the driver end  874  activating rapid reciprocating driver rod  870  impact until the fastener reaches its predetermined depth which deactivates impact. The depth to which the fastener (e.g., nail  1408  or cleat  1154 ) is driven is controlled by use of spacing washers  504  in the same manner as shown in the example of  FIG. 5 . Use of relatively more spacing washers  504  or fewer spacing washers  504  allows the user to determine the desired depth to which the fastener is set into the article (e.g., hardwood flooring board  1502 ). This embodiment enables the operator to drive fasteners in confined nail placement areas as illustrated in  FIG. 15  in addition to normal fastener placement areas. 
       FIG. 8B  illustrates a further embodiment which incorporates the same parts as the embodiment of  FIG. 8A  except that driver rod  870   a  and guide bushing  842   a  differ from driver rod  870  and guide bushing  842 . As illustrated in  FIG. 8B , driver rod  870   a  is a straight rod which lacks shoulder  872  of stepped driver rod  870  of  FIG. 8A  and has a width (i.e., a cross-sectional area) greater than the width of portion  876  of rod  870 . Also as illustrated in  FIG. 8B , guide bushing  842   a  has a straight bore  844   a  which is sized to accommodate driver rod  870   a  and guide bushing  842   a  lacks the interior peripheral collar  847  of guide bushing  842 . The examples of  FIGS. 8A and 8B  illustrate that different driver rods and guide bushings can be implemented and interchanged. 
     This embodiment consists of a securing collar  100 , a tapered guide bushing  101 , prior art straight guide bushing  102 , a spring  103 , a spacing washer  104 , a lower housing body  105 , a driver  106 , a piston  107 , a cylinder  111 , an upper housing body  108 , a pressurized air inlet  113  which receives pressurized air from a pressurized air source and a assembly screw set  109 . In the example of  FIG. 1 , piston  107  is seated in cylinder  111  as is known in the art. Cylinder  111  is mounted within upper and lower housing bodies  105 ,  108 . Piston  107  repeatedly reciprocates back and forth in short strokes in cylinder  111  to provide an intermittent force delivered by driver  106  to a fastener (e.g., nail  1408  or cleat  1154 ) in guide bushing  101  when pressurized air enters air inlet  113  from a pressurized air source and the tool is activated. The intermittent force is used to drive the fastener (e.g., a nail  1408  or a cleat  1154 ) supported by an inventive guide bushing  101  essentially fully into an article such as the tongue-and-groove flooring board  1502  illustrated in  FIG. 15 . 
       FIG. 2  is an enlarged perspective view of a tapered guide bushing  220  according to a further embodiment of the invention. 
     Guide bushing  220  is provided with a taper  222  to a flat tip  226 . A magnet  228  is adhered in a bore  230  perpendicular to guide bushing  220  which intersects an off centered bushing bore  224 . The guide bushing  220  has a stepped centered shoulder bore  236 , forming a shoulder  234 , and a stepped bore  238  forming a spring seat  240 . The guide bushing  220  has an upper peripheral collar  232  (a type of shoulder). 
       FIG. 3  is an enlarged perspective view of a driver  106  of the palm nailer of  FIG. 1 . 
     The driver  106  consists of a straight driver  300 , a driver end  302 , an upper shoulder  306 , and a threaded end  308 . The treaded end  308  is connected to a piston  310 . Piston  310  is reciprocatingly driven within cylinder  111  by pressurized air when the tool is activated. 
       FIG. 4  is an enlarged view of the tip of a tapered guide bushing  420  (showing a circumferential groove for receiving a cushioned tip/boot) according to a further embodiment of the invention. 
       FIG. 4  shows a guide bushing  420  with a taper  422  to a flat tip  426  joining a guide bore  424 . The taper has an o-ring groove  428  cut in the upper circumference of the taper  422  to hold a protective cushioned boot  430  by an upper o-ring band  432 . The boot  430  fits the flat tip  426  with a flat sided o-ring sole  434 . The o-ring sole  434  does not protrude within the bore  424 . The sole  434  provides the guide bushing tip with a non-marring surface. The o-ring sole  434  may include a flexible nail centering retainer  438  which allows enough room for a finish nail to be set through the retainer  438  and into the guide bushing bore  424  for driving. 
       FIG. 6  is a further enlarged perspective view of the tapered guide bushing  520  of  FIGS. 5 and 5A . 
       FIG. 6  shows guide bushing  520  with a taper  522  to a sharp edge tip  526 . A magnet  528  is adhered in a bore  530  which is perpendicular to bore  524  and intersects guide bushing bore  524 . The guide bushing  520  has a stepped center bore  536  forming a shoulder  534 . The guide bushing  520  has a stepped bore  538  forming a spring seat  539  . The guide bushing  520  has an upper peripheral collar  532 . 
       FIG. 7  is an enlarged perspective view of a stepped driver  570  of the palm nailer of  FIG. 5 . 
       FIG. 7  shows a stepped driver  570  which consists of a driving end  576 , a mid shoulder  544 , an upper shoulder  706 , and the threaded end  574 . The threaded end  574  is connected to a piston  572 . Piston  572  is reciprocatingly driven back and forth within cylinder  573  by pressurized air when the tool is activated. 
       FIG. 9  is an enlarged perspective view of the tapered guide bushing (with an apse tip, that is a rounded tip) according to a further embodiment of the invention. 
       FIG. 9  shows a guide bushing  920  with a taper  922  to an apse tip  926 . A magnet  928  is adhered in a bore  930  which is perpendicular with and intersects a guide bushing straight bore  924 . The top of the guide bushing  920  has a guide sleeve  934  inserted into a bore  936  on a flat top spring seat  938 . The guide bushing  920  has an upper peripheral collar  932  (a type of shoulder). 
       FIG. 10  illustrates a guide bushing  1020  with a taper  1022  to a flat tip  1026 . A magnet  1028  is adhered in a bore  1030  perpendicular to a guide bushing bore  1024 . A shoulder bore  1025  forms a shoulder  1036  in the guide bore  1024 . The top of the guide bushing  1020  has a stepped bore  1038  forming a spring seat  1040 . The upper edge of bushing  1020  has a peripheral collar  1032  (a type of shoulder). 
       FIG. 11  shows a tapered guide bushing  1120  with a main taper  1122  on two sides leaving a shoulder  1100  on each side of the circumference. The taper  1122  joins a beveled tip  1126 . The tapered guide bushing  1120  has a flat directional guide  1140  on the outside surface of the cylinder wall, which matches a directional guide washer  1150  with a congruent flat portion  1152 . A magnet  1128  is adhered in a perpendicular bore  1130  which intersects a guide bushing straight bore  1124 . The guide bushing bore  1124  has a broached bore  1142  including a pair of rectangular portions for orienting a flat fastener (e.g., cleat  1154 ) for driving leaving a Saturn shaped guide bore  1144 . The upper edge has a peripheral collar  1132  (a type of shoulder). The top of the guide bushing  1120  has a flat spring seat  1138 . This embodiment is used for driving rectangular floor cleats  1154 . 
       FIG. 12  is a perspective view of a prior art palm nailer.  FIG. 12  shows a prior art palm nailer  1200  with a standard guide bushing  1202 . 
       FIG. 13  is an enlarged perspective view of a palm nailer with a tapered guide bushing according to a further embodiment of the invention.  FIG. 13  shows a palm nailer  1300  with a tapered guide bushing  1302  which is able to be positioned into compact areas for nail placement. 
       FIG. 14  is a perspective view of a prior art palm nailer positioned to drive a nail in a confined space or angled location and is unable to achieve the proper result.  FIG. 14  shows an operator  1400  installing a tongue and a groove pre-finished hardwood floor  1402  in a confined space near a wall  1404 , with a prior art mini palm nailer  1406 . Most mini palm nailers  1406  are unable to drive a finish nail  1408  successfully. A bent nail can damage the floor finish. Mini palm nailers  1406  are set up for common nails up to 16d nails. If the mini palm nailer  1406  is able to drive the finish nail  1408  the driver is unable to drive much father than a large flat tip guide bushing  1410 . The guide bushing  1410  which is resting on a finished floor edge  1412  and on a floor tongue  1414  will not allow the nail  1408  to be set properly. If the nail bending does not damage the floor  1402 , the guide bushing  1410  will damage finished floor edge  1412 . 
       FIG.15  is a perspective view of a palm nailer according to the present invention positioned to drive a nail in a confined space or angled location.  FIG. 15  shows an operator  1500  installing a tongue and groove pre-finished hardwood floor  1502  in a confined space near a wall  1504  with a mini palm nailer  1506  according to this embodiment. This embodiment of the palm nailer  1506  is able to drive the finish nail  1508  successfully. The Palm nailer is designed with a guide bushing  1510  that supports the finish nail  1508  and sets the nail  1508  properly. The palm nailer  1506  is able to rest on top of the tongue  1514  and beneath the floor edge  1512  and move freely to adjust the nailing angle without damaging the floor edge  1512 . This embodiment will save many hours on a hard wood flooring installations and other types of work.