Patent Publication Number: US-2006011693-A1

Title: Guidance system for fasteners

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention is directed to a guidance system for a fastener driving tool for guiding fasteners to a drive bore and thenceforward to a work surface.  
      2. Description of the Related Art  
      Many fastener driving tools are adapted with a magazine for feeding fasteners held in collations into a drive bore. Prior collations hold fasteners proximate their heads regardless of overall fastener length, so that long fasteners typically have a long shank portion below the collation and short fasteners typically have a short shank portion below the collation. Tools for driving fasteners typically have an opening into the drive bore long enough for the long shank portions so that a user may use the same tool for both short fasteners and long fasteners. However, a long drive bore opening provides an exit that may allow the short shank portions of short fasteners to tip or angle into the opening as short fasteners are driven, also known as “diving back” or “tumbling” into the magazine. Diving back may cause inaccurate driving of the fastener, jamming of the tool, or damage to the tool due to large forces needed to drive the fasteners into the substrate. These problems are exacerbated when combustion-powered tools are used to drive fasteners into concrete or steel.  
      One method that has been used to reduce diving back is to provide a plurality of nail head guide tracks in the magazine, one for each length of fastener, see U.S. Pat. No. 6,173,877. However, the magazine is only used to feed fasteners, not fasteners in collations. Also, a user must take great care to ensure that the head is placed in the appropriate channel for a fastener having a given length.  
      Another problem with prior fastener driving tools has been recoil of the tool due to firing. Many fastener driving tools have a fastener guide that recoils along with the tool body as the tool is fired so that the fastener guide lifts off of the substrate, which can cause the fastener to be in free flight between the fastener guide and the substrate, which may cause improper fastener placement or alignment. The fastener driving tool disclosed in the commonly assigned U.S. Pat. No. 6,138,887 teaches a fastener guide movable with respect to a tool body so that the fastener guide remains in abutment with the work surface as the tool recoils due to its firing. However, the fastener loading position of the tool moves with respect to the magazine so that the fastener in the drive bore may move up or down with respect to subsequent fasteners, which can allow more than one fastener to be loaded into the drive bore prior to firing or which can cause the fastener guide to impinge on the collation as it enters the drive bore. Firing a tool with multiple fasteners loaded in the drive bore or with a collation that is impinged by the fastener guide may cause jamming or damage to the tool.  
      What is needed is a fastener driving tool that overcomes the problems of the prior art.  
     BRIEF SUMMARY OF THE INVENTION  
      A tool is provided for driving fasteners toward a work surface, the tool including a body having a forward end, a rear end, and a cylinder with an axis, a piston mounted within the cylinder, a power source for driving the piston axially forwardly, a driver blade extending axially forwardly from the piston, a nosepiece extending axially forwardly from the front end of the tool body, wherein the nosepiece encloses a drive bore for guiding the fasteners and the driver blade toward the work surface, there being an opening into the drive bore for the fasteners, and a magazine for guiding the fasteners to the opening. In one aspect of the invention, the magazine and the nosepiece are fixed with respect to each other and a fastener guide is included that extends axially forwardly from the nosepiece, wherein the fastener guide is movable with respect to the nosepiece between an extended position and a retracted position.  
      In another aspect of the invention, fasteners are collated by a plurality of sleeves, wherein each fastener has a tip. An opening into the drive bore of a fastener driving tool provides a small clearance through which the fastener tips can pass. In one embodiment, each fastener has a predetermined exposed tip length, and the opening into the drive bore provides this clearance with a tip channel having a depth that is slightly greater than the predetermined exposed tip length of the fastener.  
      In still another aspect, the main channel of the opening into the drive bore comprises a sleeve channel for accommodating the sleeves and a head channel for accommodating fastener heads.  
      In yet another aspect, the magazine of the fastener driving tool has a feed passageway comprising a collation channel for accommodating the sleeves and a head channel for accommodating fastener heads.  
      A system is provided for fastening a work piece to a substrate, the system including a first collation of fasteners, a second collation of fasteners, and a fastener driving tool. The first collation has a plurality of sleeves holding first fasteners each having a tip. The second collation has a plurality of sleeves holding second fasteners each having a tip, wherein the second fasteners are of different length than the first fasteners. Each set of collations fits through the opening into the drive bore so that a small clearance is provided between the fastener tip and the opening. In one system, the fasteners of each set of collations have the same predetermined exposed tip length, and the opening into the drive bore includes a tip channel having a depth that is slightly greater than the predetermined exposed tip length of the fasteners so that the small clearance is provided.  
      A method of selecting and driving fasteners includes providing a first collation of a plurality of sleeves holding first fasteners each having a tip and a second collation of a plurality of sleeves holding second fasteners each having a tip, wherein the second fasteners are of different length than the first fasteners. The first fasteners and the second fasteners are adapted to be individually driven through a drive bore of a fastener driving tool by a drive member. There is an opening into the drive bore having a channel that provides a small clearance through which the tips can pass, the main channel being long enough to accommodate the first fasteners and the second fasteners. The method includes the steps of selecting one of the first collation and the second collation for desired length of fastener, feeding the fasteners of the selected collation through the opening, and driving the fasteners of the selected collation with the drive member.  
      These and other features and advantages are evident from the following description of the present invention, with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       FIG. 1  is a partial side sectional view of a fastener driving tool with a nosepiece in an extended position.  
       FIG. 2  is a partial side sectional view of the fastener driving tool with the nosepiece in a retracted position, wherein the nosepiece is pushed against a work surface.  
       FIG. 3  is a sectional view of a loading opening into a drive bore of the fastener driving tool, taken along line  3 - 3  in  FIG. 1 .  
       FIG. 4  is a sectional view of a first guidance zone of a magazine of the fastener driving tool, taken along line  4 - 4  in  FIG. 1 .  
       FIG. 5  is a sectional view of a second guidance zone of the magazine, taken along line  5 - 5  in  FIG. 1 .  
       FIG. 6  is a close side sectional view of the nosepiece, a fastener guide and a shear block of the fastener driving tool, wherein the nosepiece is in the extended position.  
       FIG. 7  is a close side sectional view of the nosepiece, the fastener guide, and the shear block, wherein the nosepiece is in the retracted position.  
       FIG. 8A  is a side view of a first collation of the present invention, wherein the first collation holds short fasteners.  
       FIG. 8B  is a side view of a second collation that holds medium fasteners.  
       FIG. 8C  is a side view of a third collation that holds long fasteners.  
       FIG. 9  is an elevation view of collations, taken along line  9 - 9  in  FIG. 8C .  
       FIG. 10  is a sectional view of a sleeve of the collation, taken along line  10 - 10  in  FIG. 9 .  
       FIG. 11  is a sectional view of a sleeve taken along line  11 - 11  in  FIG. 9 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIGS. 1 and 2 , a fastener driving tool  10  is shown having a guidance system that accommodates fasteners  12   a ,  12   b ,  12   c  of various lengths FL in collations  64   a ,  64   b ,  64   c  (see  FIGS. 8A-8C ) for driving fasteners  12   a ,  12   b ,  12   c  into a substrate  2 . Tool  10  includes a tool body  20  having a front end  22 , a rear end  24 , and a cylinder  26  with an axis  28 , a piston  30  mounted within cylinder  26 , a power source, such as a combustion chamber  34  for combusting fuel, for driving piston  30  axially forwardly, a driver blade  32  extending axially forwardly from piston  30 , a nosepiece  36  extending axially forwardly from front end  22  of tool body  20 , wherein nosepiece  36  encloses a drive bore  38  for guiding fasteners  12   a ,  12   b ,  12   c  and driver blade  32  toward work surface  6 , there being a loading opening  40  into drive bore  38  for fasteners  12   a ,  12   b ,  12   c , and a magazine  42  for guiding fasteners  12   a ,  12   b ,  12   c  to loading opening  40 . In one aspect of the invention, magazine  42  and nosepiece  36  are fixed with respect to each other, and tool  10  further includes a fastener guide  44  extending axially forwardly from nosepiece  36 , wherein fastener guide  44  is movable with respect to nosepiece  36  between an extended position ( FIG. 1 ) and a retracted position ( FIG. 2 ).  
      Turning to  FIG. 3 , in another aspect, loading opening  40  into drive bore  38  has a main channel  120  and a tip channel  124  protruding a predetermined channel depth TCD from main channel  120 , wherein the predetermined tip channel depth TCD is slightly larger than a predetermined exposed tip length TL between tip  18   a ,  18   b ,  18   c  of fastener  12   a ,  12   b ,  12   c  and a front end  74  of a corresponding collation sleeve  58  that is holding fastener  12   a ,  12   b ,  12   c , so that there is a small clearance through which tips  18   a ,  18   b ,  18   c  can pass, wherein main channel  120  is long enough to accommodate fasteners  12   a ,  12   b ,  12   c  of at least two different lengths FL.  
      As shown in  FIGS. 8A-8C , collation  64   a ,  64   b ,  64   c  is provided for transporting fasteners  12   a ,  12   b ,  12   c  along rails  86  disposed within magazine  42 . Collation  64   a ,  64   b ,  64   c  includes a plurality of sleeves  58  for supporting and carrying fasteners  12   a ,  12   b ,  12   c  through magazine  42 . Each sleeve  58  has a length of between about ¼ inch and about 0.4 inch, and each fastener  12   a ,  12   b ,  12   c  has a predetermined exposed tip length TL from said sleeve  58  of between about ⅛ inch and about ¼ inch. A plurality of frangible bridges  96 ,  97  are also provided integrally connecting sleeves  58  together in a serial array, and facilitating separation of a leading sleeve  58  from the remaining sleeves  58  when driver blade  32  drives a leading fastener  12   a ,  12   b ,  12   c  held within the leading sleeve  58 . Fasteners  12   a ,  12   b ,  12   c  having various lengths FL, as shown in  FIGS. 8A-8C , may be used by tool  10 , wherein different length FL fasteners are used for different applications. In one embodiment, fasteners having a length FL of between about ¾ inch and about 1 inch are used in collations  64   a ,  64   b ,  64   c.    
      Tool  10  drives fasteners  12   a ,  12   b ,  12   c  for fastening a work piece  4  to a substrate  2 . Preferably, tool  10  is designed for fastening work piece  4  to a hard substrate  2 , such as concrete or steel used in commercial construction. Work piece  4  may be thin, such as thin sheet steel, or work piece  4  may be relatively thick, such as plywood. In one embodiment, tool  10  is used to drive fasteners  12   a ,  12   b ,  12   c  to anchor metal tracking, see  FIG. 2 , to concrete floors, ceilings or walls, wherein studs are attached to the tracking in order to mount drywall to the studs to build walls.  
      1 Tool Overview  
      Returning to  FIGS. 1 and 2 , tool  10  includes a body  20  having a front end  22  and a rear end  24 , with a handle  46  depending from body  20  for a user to hold tool  10 . A trigger  48  is mounted to handle  46  for actuating tool  10 . Tool  20  encloses a cylinder  26  having an axis  28 , wherein a reciprocating piston  30  is mounted within cylinder  26  so that piston  30  is coaxial with cylinder  26  and so that piston  30  slides within cylinder  26 . Piston  30  is driven axially forwardly toward front end  22  by a pressurized gas to the rear of piston  30 . A power source is included to provide the pressurized gas to drive piston  30  axially forwardly in the driving direction. The power source may provide pressurized gas pneumatically using pressurized air fed to a pneumatic cylinder (not shown), by combustion of fuel in a combustion chamber  34 , or by exploding powder in a powder actuated tool. Because tool  10  is preferably designed for driving fasteners  12   a ,  12   b ,  12   c  into a hard substrate, such as concrete or steel, in one embodiment, shown in  FIGS. 1 and 2 , the power source is a combustion chamber  34  for combusting fuel to provide the large force needed to drive fasteners  12   a ,  12   b ,  12   c  into concrete or steel.  
      Tool  10  may also include a combustion chamber sleeve  50  mounted in tool body  20  in a sliding manner so that sleeve  50  is movable between an open position ( FIG. 1 ) and a closed position ( FIG. 2 ). When sleeve  50  is in the open position, combustion chamber  34  is also open and tool  10  cannot be fired. When sleeve  50  is moved into the closed position, it closes combustion chamber  34 , so that when tool  10  is fired, the pressurized gas acts to drive piston  30  in the driving direction. Combustion chamber sleeve  50  is operatively connected to fastener guide  44  of tool  10  (described below), so that when fastener guide  44  is pushed against a work surface  6 , it pushes sleeve  50  into the closed position, which closes combustion chamber  34 , allowing tool  10  to be fired only when fastener guide  44  is pushed against work surface  6 .  
      Continuing with  FIGS. 1 and 2 , driver blade  32  extends forwardly from piston  30  so that driver blade  32  is driven forwardly along with piston  30 . In one embodiment, driver blade  32  is a separate piece that is mounted to piston  30 , allowing driver blade  32  to be manufactured separately from piston  30 . Driver blade  32  has a leading end  52  that strikes fastener head  16   a ,  16   b ,  16   c  to drive fastener  12   a ,  12   b ,  12   c  toward a work surface  6  on work piece  4 . Preferably, driver blade  32  is generally cylindrical so that it corresponds to fastener head  16   a ,  16   b ,  16   c  and drive bore  38 .  
      A resilient buffer  54  is located at leading end  56  of cylinder  26  to protect piston  30  and cylinder  26  from damage by absorbing shock from piston  30 . Buffer  54  may be made from a resilient plastic, and preferably is made from urethane or rubber.  
      Turning to  FIGS. 1, 2 ,  6 , and  7 , a nosepiece  36  extends forwardly from front end  22  of tool body  20 , wherein nosepiece  36  encloses drive bore  38  to guide fasteners  12   a ,  12   b ,  12   c  and driver blade  32  toward work surface  6 . Loading opening  40  preferably has a geometry that permits fastener  12   a ,  12   b ,  12   c  and its corresponding sleeve  58  to pass through loading opening  40  and into drive bore  38  only when fastener  12   a ,  12   b ,  12   c  and sleeve  58  are oriented properly. Preferably, loading opening  40  also has a geometry that eliminates the exit for short fasteners in order to prevent their tips from diving back out of drive bore  38 .  
      In one embodiment, nosepiece  36  includes an axially extending generally semi-circular groove which makes up part of drive bore  38 . A shear block  60  is mounted to nosepiece  36 , wherein shear block  60  also includes an axially extending generally semi-circular groove that corresponds to and is registered with the semi-circular groove of nosepiece  36  so that the semi-circular grooves form drive bore  38  so that both nosepiece  36  and shear block  60  guide fasteners  12   a ,  12   b ,  12   c  and driver blade  32  toward work piece  4  and substrate  2 . Preferably, shear block  60  is removable, allowing a user to perform maintenance on tool  10 , such as clearing out jams in drive bore  38 . Preferably, shear block  60  includes loading opening  40  so that shear block  60  guides fasteners  12   a ,  12   b ,  12   c  into drive bore  38 .  
      2 Collations  
      Turning to  FIGS. 8A-8C  and  9 , different collations  64   a ,  64   b ,  64   c  may be provided for different applications. For example, a first collation  64   a  holds short fasteners  12   a , which are used for one application, wherein each fastener  12   a  has a tip  18   a  that is located at a predetermined position relative to front end  74  of sleeve  58 . A second collation  64   b  holds medium fasteners  12   b  which may be used for another application, wherein each fastener  12   b  has a tip  18   b  that is located at the same predetermined position relative to front end  74 . Similarly, a third collation  64   c  holds long fasteners  12   c , which may be used for yet another application, wherein each fastener  12   c  has a tip  18   c  that is located at the same predetermined position relative to front end  74 . Preferably, each fastener tip  18   a ,  18   b ,  18   c  protrudes beyond front end  74  so that each fastener  12   a ,  12   b ,  12   c  has a predetermined tip length TL.  
      Each collation  64   a ,  64   b ,  64   c  includes a carrier  65  fabricated from a suitable polymeric material. In one embodiment, carrier  65  is molded from a plastic, and preferably from polypropylene. Carrier  65  comprises a plurality of sleeves  58  arranged substantially in a linear row, wherein each sleeve  58  includes a rear end  72  and a front end  74 , with a bore  76  extending between rear end  72  and front end  74  for receiving a corresponding fastener  12   a ,  12   b ,  12   c . Collation  64   a ,  64   b ,  64   c  is manufactured by first molding carrier  65  of sleeves  58 , which are connected together in a row, followed by inserting fasteners  12   a ,  12   b ,  12   c  into sleeves  58  to create collation  64   a ,  64   b ,  64   c . Adjacent sleeves  58  of collation  64   a ,  64   b ,  64   c  are integrally connected together by at least one bridge  96 ,  67 , and in one embodiment, adjacent sleeves  58  are connected together by an upper bridge  96  and a lower bridge  97 .  
      Preferably, carrier  65  is substantially symmetrical about both a horizontally oriented axis and a vertically oriented axis so that carrier  65  may be properly used within magazine  42  of a fastener driving tool  10  regardless of whether or not the carrier  65  is effectively rotated 180° around either axis so that what was formerly the upper end of a sleeve is now the lower end, and what was formerly the leading sleeve is now the trailing sleeve. Also, symmetrical objects are easier to mold, and hence simplify the process of manufacturing carrier  65 . However, carrier  65  can also be unsymmetrical if desired. Collation  64   a ,  64   b ,  64   c  may have between about five and about fifty sleeves  58  arranged in a linear row, preferably between about ten and about twenty sleeves  58 , still more preferably about fifteen sleeves  58 .  
      2.1 Fasteners  
      Continuing with  FIGS. 8A-8C , preferably, fasteners  12   a ,  12   b ,  12   c  are used to fasten a work piece  4 , such as the metal track shown in  FIG. 2 , to a hard substrate  2 , such as concrete or steel used in commercial construction. Each fastener  12   a ,  12   b ,  12   c  has an elongate shank  14   a ,  14   b ,  14   c  with a head  16   a ,  16   b ,  16   c  at one end and a tip  18   a ,  18   b ,  18   c  at the opposite end. Fastener  12   a ,  12   b ,  12   c  includes an ogive  19   a ,  19   b ,  19   c  that tapers from the end of shank  14   a ,  14   b ,  14   c  to tip  18   a ,  18   b ,  18   c , wherein ogive  19   a ,  19   b ,  19   c  is generally conical in shape. Fasteners  12   a ,  12   b ,  12   c  are drive pins made from metal that provide sufficient tensile strength, toughness, and durability to be driven through work piece  4  and into a hard substrate  2 , which may be concrete or steel, without bending or breaking. In one embodiment, fasteners  12   a ,  12   b ,  12   c  are made from a heat treated high carbon steel alloy, preferably from an AISI 1060-1065 steel alloy that is heat treated with an austemper process to a core hardness of between about 52 and about 56 Rockwell C hardness. Fasteners  12   a ,  12   b ,  12   c  may also be made from stainless steel alloys for corrosion resistance, or other metals or metal alloys.  
      Fasteners  12   a ,  12   b ,  12   c  which are used for driving into concrete or steel preferably have a shank diameter of between about 1/16 inch and about 3/16 inch, preferably between about 0.1 inch and about 0.15 inch, still more preferably about ⅛ inch and a head diameter of between about ⅛ inch and about ⅜ inch, preferably between about 0.2 inch and about 0.3 inch, still more preferably about ¼ inch.  
      The length FL of fasteners  12   a ,  12   b ,  12   c  depends on the desired application. For example, short fasteners  12   a , shown in  FIG. 8A , having a length FL (measured between tip  18   a  and the bottom of head  16   a ) of between about ¼ inch and about ⅝ inch, preferably between about ⅜ and about 9/16, still more preferably about ½ inch, are used to attach thin metal work pieces  4 , such as the metal track shown in  FIG. 2 , to a hard substrate  2 , such as concrete or steel. Short fastener  12   a  is preferred for this type of application because relatively short fasteners have a relatively high column strength in their shanks, which allows short fastener  12   a  to withstand the high force needed to drive fastener  12   a  though metal work piece  4  and into the hard substrate  2 . Short fastener  12   a  may also be used if an application does not require a higher holding strength that may be provided by longer fasteners.  
      Longer fasteners, such as medium fasteners  12   b , shown in  FIG. 8B , having a length FL of between about ⅝ inch and about ⅞ inch, preferably between about 11/16 inch and about 13/16 inch, still more preferably about ¾ inch, or long fasteners  12   c , shown in  FIG. 8C , having a length FL between about ⅞ inch and about 2 inches, preferably between about 15/16 inch and about 1½ inch, still more preferably about 1 inch, have smaller column strengths than short fastener  12   a , so that longer fasteners  12   b ,  12   c  may not be ideal for fastening a thin metal work piece  4  to hard concrete or steel because shank  14   b ,  14   c  is more likely to bend or break. Also, tool  10  may need more driving power to drive longer fasteners  12   b ,  12   c  into a hard substrate  2 , particular a thick substrate  2  such as concrete, but longer fasteners  12   b ,  12   c  may provide more holding strength once they are installed. However, thicker work pieces, such as plywood (not shown), may accommodate longer fasteners  12   b ,  12   c  because the thicker work piece acts to brace longer shanks  14   b ,  14   c  to compensate for their smaller column strength. Also, longer shanks  14   b ,  14   c  are needed to extend through thicker work pieces and into the substrate, so that the work piece and substrate and fastened together.  
      In one system for use with concrete or steel substrates  2 , three sets of collations  64   a ,  64   b ,  64   c  carrying fasteners  12   a ,  12   b ,  12   c  are provided having nominal lengths of ½ inch (short fasteners  12   a ), ¾ inch (medium fasteners  12   b ), and 1 inch (long fasteners  12   c ), so that a user may select which fasteners  12   a ,  12   b ,  12   c  are appropriate for a given application.  
      2.1.1 Position of Tip  
      Continuing with  FIGS. 8A-8C , in one embodiment, each fasteners  12   a ,  12   b ,  12   c  has a tip  18   a ,  18   b ,  18   c  that is located at a predetermined position relative to front end  74  of sleeve, preferably so that there is a small exposed tip length TL, which may include part of all of ogive  19   a ,  19   b ,  19   c  and tip  18   a ,  18   b ,  18   c , and also may include part of shank  14   a ,  14   b ,  14   c . Preferably, the position of tip  18   a ,  18   b ,  18   c  is substantially uniform regardless of what length FL of fastener  12   a ,  12   b ,  12   c  is used. As shown in  FIGS. 8A-8C , exposed tip length TL of short fastener  12   a  is the same as exposed tip length TL of medium fastener  12   b , and the same exposed tip length TL of long fasteners  12   c.    
      Also, preferably, the predetermined exposed tip length TL between front sleeve end  74  and corresponding fastener tip  18   a ,  18   b ,  18   c  is as small as possible without affecting the alignment of fastener  12   a ,  12   b ,  12   c  within sleeve  58  so that sleeve  58  provides guidance to tip  18   a ,  18   b ,  18   c  as fastener  12   a ,  12   b ,  12   c  is driven toward work surface  6  so that the likelihood that fastener tip  18   a ,  18   b ,  18   c  will begin to dive back toward magazine  42  is reduced. The close spacing of front sleeve end  74  and fastener tip  18   a ,  18   b ,  18   c  helps prevent fasteners  12   a ,  12   b ,  12   c  from diving back into magazine  42  because it allows tool  10  to be configured to remove the exit path that may allow fastener tip  18   a ,  18   b ,  18   c  to exit drive bore  38  through loading opening  40 , described below. Also, because of the small predetermined exposed tip length TL, sleeves  58  provide guidance to tips  18   a ,  18   b ,  18   c  as fastener  12   a ,  12   b ,  12   c  is driven toward work surface  6  so that the likelihood that fastener tip  18   a ,  18   b ,  18   c  will begin to dive back toward magazine is reduced. In addition, sleeve  58  aligns tip  18   b ,  18   c  of longer fasteners  12   b ,  12   c  with axis  28  so that tips  18   b ,  18   c  remain centered in bore when the leading sleeve  58  is sheared from the second sleeve  58 , and tip  18   b ,  18   c  is captured by fastener guide  44 .  
      The predetermined position of tip  18   a ,  18   b ,  18   c  relative to front sleeve end  74  is selected so that tip  18   a ,  18   b ,  18   c  is positioned in a zone relative to front sleeve end  74  between fastener tip  18   a ,  18   b ,  18   c  being slightly recessed within bore  76 , i.e. about 0.05 inch behind front end  74  and a position that protrudes from sleeve  58  so that an exposed tip length TL is formed. Fastener tip  18   a ,  18   b ,  18   c  may be flush with front end  74  or recessed within sleeve bore  76 , however, it may be difficult to ensure the alignment of fastener  12   a ,  12   b ,  12   c  and the support of fastener shank  14   a ,  14   b ,  14   c  if tip  18   a ,  18   b ,  18   c  is recessed within bore  76 , therefore, for practical reasons, in one embodiment front sleeve end  74  is positioned within this zone so that tip  18   a ,  18   b ,  18   c  has an exposed tip length TL below front sleeve end  74 . In one embodiment, the predetermined position of tip  18   a ,  18   b ,  18   c  is located between about 0.1 inch behind front end  74  of sleeve  58  and about ½ inch beyond front end  74 , preferably between about 0.05 inch behind front end  74  and about ¼ inch beyond front end  74 , and still more preferably so that tip  18   a ,  18   b ,  18   c  has an exposed tip length TL of about 0.2 inch.  
      In one embodiment, collations  64   a ,  64   b ,  64   c  are manufactured by inserting fasteners  12   a ,  12   b ,  12   c  through sleeve bores  76 , and fastener tips  18   a ,  18   b ,  18   c  may be placed within a manufacturing tolerance of about 0.025 inch from the desired exposed tip length TL. For example, if the desired exposed tip length TL is about 0.205 inch, then during manufacturing of collations  64   a ,  64   b ,  64   c , fastener tips  18   a ,  18   b ,  18   c  should be placed between about 0.18 inch and about 0.23 inch from front sleeve ends  74 .  
      2.1.2 Exposed Neck Length  
      Continuing with  FIGS. 8A-8C , because the exposed tip length TL of fasteners  12   a ,  12   b ,  12   c  may be uniform regardless of the length FL of fastener  12   a ,  12   b ,  12   c  that is used, the length NL of an exposed neck  17   a ,  17   b ,  17   c  of fasteners  12   a ,  12   b ,  12   c  will vary depending on the length FL of fastener being used. For example, for short fasteners  12   a  having a length FL of between about ¼ inch and about ¾ inch, neck  17   a  has a length NL of between about 0 inch, wherein head  16   a  is abutted against rear end  72 , and about 0.05 inch, preferably between about 0.001 inch and about 0.02 inch, still more preferably about 0.005. For longer fasteners, such as medium fasteners  12   b  or long fasteners  12   c , the exposed neck length NL is preferably between about 0.2 inch and about 1½ inch. In one embodiment, for medium fasteners  12   b  having a length FL of about ¾ inch, neck  17   b  has a length NL of between about 0.1 inch and about ⅜ inch, preferably between about 0.2 inch and about ¼ inch, still more preferably about 0.22 inch, and for long fastener  12   c  having a length FL of about 1 inch, neck  17   c  has a length NL of between about ⅜ inch and about ¾ inch, preferably between about 0.4 inch and about ⅝ inch, still more preferably about 0.47 inch.  
      Also, for longer fasteners  12   b ,  12   c , it is preferred that the exposed neck length NL be approximately at least as long as exposed tip length TL, and for long fasteners  12   c , approximately at least twice as large as exposed tip length TL.  
      2.2 Sleeves  
      Continuing with  FIGS. 1 and 8 A- 8 C, fasteners  12   a ,  12   b ,  12   c  are collated in a row by collation  64   a ,  64   b ,  64   c  which includes a plurality of collation sleeves  58  connected together in series, wherein each sleeve  58  holds and supports a fastener  12   a ,  12   b ,  12   c . Collation  64   a ,  64   b ,  64   c  provides a plurality of fasteners  12   a ,  12   b ,  12   c  connected together as a single unit, which is easier for a user of tool  10  to manipulate. Collation  64   a ,  64   b ,  64   c  also provides proper spacing between adjacent fasteners  12   a ,  12   b ,  12   c  to ensure that tool  10  only drives one fastener  12   a ,  12   b ,  12   c  at a time. The width across sleeve  58  is preferably about the same as the diameter of fastener heads  16   a ,  16   b ,  16   c  so that both sleeve  58  and fastener head  16   a ,  16   b ,  16   c  help guide fastener  12   a ,  12   b ,  12   c  as it is driven through drive bore  38 . Each sleeve may have a width of between about ⅛ inch and about ⅜ inch, preferably between about 0.2 inch and about 0.3 inch, still more preferably about 0.27 inch.  
      Collation  64   a ,  64   b ,  64   c  sequentially feeds fasteners  12   a ,  12   b ,  12   c  through loading opening  40  into drive bore  38  via a magazine  42  so that a leading fastener  12   a ,  12   b ,  12   c  is positioned within drive bore  38  to be driven by driver blade  32 . As the leading fastener  12   a ,  12   b ,  12   c  is driven through drive bore  38  by driver blade  32 , its corresponding leading sleeve  58  is sheared from a second adjacent sleeve  58 . The leading fastener  12   a ,  12   b ,  12   c  and sleeve  58  are driven through drive bore  38  toward work surface  6  on work piece  4 . As fastener  12   a ,  12   b ,  12   c  is driven into work piece  4  and substrate  2 , sleeve  58  is split apart so that it separates from fastener  12   a ,  12   b ,  12   c  or sleeve  58  becomes trapped under fastener head  16   a ,  16   b ,  16   c . In one embodiment, each sleeve  58  includes a pair of generally V-shaped notches  73  at rear sleeve end  72  and a pair of generally V-shaped notches  75  at front sleeve end  74  so that fastener  12   a ,  12   b ,  12   c  will readily split sleeve  58  as fastener head  16   a ,  16   b ,  16   c  is driven through sleeve  58 . After the leading fastener  12   a ,  12   b ,  12   c  has been driven, the spring force of a spring biased follower (not shown) in magazine  42  pushes the second fastener  12   a ,  12   b ,  12   c  into drive bore  38  so that the second fastener  12   a ,  12   b ,  12   c  becomes the leading fastener, and a third fastener becomes the second fastener.  
      Continuing with  FIGS. 8A-8C , adjacent sleeves  58  of collation  64   a ,  64   b ,  64   c  are connected with one or more frangible bridges  96 . Bridges  96  are designed to be sheared when the leading fastener  12   a ,  12   b ,  12   c  held within the leading sleeve  58   a  is driven by driver blade  32  so that the leading sleeve  58  is sheared from the second sleeve  58  along a breaking plane  98  located at the juncture between bridges  96  of the leading sleeve  58  and adjacent bridges  96  of the second sleeve  58 . Bridges  96 ,  97  may be dimensioned to maximize fastener density while avoiding jamming and improving guidance, e.g., the distance between sleeves  58  may be between about 3% and about 20%, preferably between about 5% and about 12% of the in-line thickness of sleeve  58 .  
      Each sleeve  58  ensures that corresponding fastener  12   a ,  12   b ,  12   c  is coaxially aligned within drive bore  38  of tool  10 , so that fasteners  12   a ,  12   b ,  12   c  are driven substantially perpendicularly with respect to work surface  6 , otherwise fastener  12   a ,  12   b ,  12   c  may bend or be driven crooked, preventing proper fastening of work piece  4  to substrate  2 , or fastener  12   a ,  12   b ,  12   c  may ricochet off of the substrate  2  due to the hardness of substrate  2  and the force in which fastener  12   a ,  12   b ,  12   c  is driven.  
      Each fastener  12   a ,  12   b ,  12   c  is inserted through a corresponding sleeve  58  of carrier  65  so that fastener  12   a ,  12   b ,  12   c  has a predetermined exposed tip length TL from front end  74  of the corresponding sleeve  58 , and head  16   a ,  16   b ,  16   c  is spaced a predetermined distance NL from rear end  72  of the corresponding sleeve  58 . Each sleeve  58  has a predetermined axial length that is long enough to properly align and support fastener  12   a ,  12   b ,  12   c , yet not so long as to be overly expensive. In one embodiment, the predetermined axial length of each sleeve  58  is between about ⅛ inch and about ½ inch, preferably between about ¼ inch and about 0.4 inch, still more preferably about 0.32 inch. In one embodiment, each sleeve  58  includes a plurality of protrusions, such as collars  78 ,  80 , integrally provided upon sleeve  58  for engaging rails  86  within magazine  42 .  
      Sleeves  58  may be formed into one of many geometric shapes, including cylindrical, but in one embodiment, shown in  FIG. 9 , each sleeve  58  has a substantially square-shaped cross section and sleeve bore  76  also has a substantially square-shaped cross section with interior side walls  77 , while fastener shanks  14   a ,  14   b ,  14   c  have a substantially circular cross section. A portion of each fastener shank  14   a ,  14   b ,  14   c  will engage a corresponding interior side wall  77  of a corresponding sleeve  58  at a substantially central portion of interior side wall  77  and along a substantially vertically oriented locus along interior side wall  77  (shown as long fastener shank  14   c  in  FIG. 9 ). In one embodiment, each interior side wall  77  includes one or more crush ribs or dimples  79 , best shown in  FIGS. 9 and 10 , to accommodate fastener shanks  14   a ,  14   b ,  14   c , which have a predetermined diameter within machined tolerances. Sleeves  58  may be dimensioned to maximize fastener density while avoiding jamming and improving guidance, e.g., each sleeve  58  may have an in-line thickness and a transverse thickness that is approximately equal to, e.g. between about 95% and about 110%, of the diameter of fastener heads  16   a ,  16   b ,  16   c  with close spaces provided by bridges  96 ,  97 .  
      Continuing with  FIGS. 10 and 11 , in one embodiment, each sleeve  58  includes an upper collar  78  at rear end  72  and a lower collar  80  at front end  74  wherein upper and lower collars  78 ,  80  protrude laterally outwardly from sleeve  58  so that there is a pair of lateral channels  92  on each side of sleeve  58  between upper collar  78  and lower collar  80 . Rails  86  of magazine  42  are received by channels  92  so that rails  86  engage collars  78 ,  80  and guide collation  64   a ,  64   b ,  64   c  through magazine  42 . In one embodiment, a window  94  is included in each channel  92  through which a portion of fastener shank  14   a ,  14   b ,  14   c  emerges. Fasteners  12   a ,  12   b ,  12   c  can also be held together by separate upper and lower collars (not shown), i.e. by a plurality of joined upper collars proximate fastener heads  16   a ,  16   b ,  16   c  and a plurality of separate joined lower collars proximate fastener tips  18   a ,  18   b ,  18   c.    
      Preferably, upper and lower collars  78 ,  80  each include a rail engaging member or projection  82 ,  84  for engaging rails  86  of magazine  42 . In one embodiment, projections  82 ,  84  protrude toward each other into channels  92 . A pair of upper projections  82  protrudes downwardly from upper collar  78 , while a pair of lower projections  84  protrudes upwardly from lower collar  80 , so that upper projections  82  protrude toward lower projections  84 , and lower projections  84  protrude toward upper projections  82 . Each upper projections  82  is generally vertically aligned with a corresponding lower projection  84 , and conversely each lower projections  84  is generally vertically aligned with a corresponding upper projection  82 , so that a space is defined between upper projections  82  and lower projections  84  within which rails  86  of magazine  42  may be accommodated.  
      In one embodiment, each projection  82 ,  84  has a substantially pyramidal configuration so that each projection  82 ,  84  includes a contact tip region  83 ,  85  for engaging a surface portion of one of magazine rails  86 . Preferably, each contact tip region  83 ,  85  comprises a substantially point-type radiused contact region for engaging rail  86  of magazine  42  so that the frictional forces generated between collation  64   a ,  64   b ,  64   c  and rails  86  are effectively reduced as much as possible so that the conveyance of collation  64   a ,  64   b ,  64   c  through magazine  42  is as smooth as possible to avoid hang-ups.  
      3 Magazine  
      Turning to  FIGS. 1, 4  and  5 , a magazine  42  is provided to feed fasteners  12   a ,  12   b ,  12   c  to loading opening  40  so that fasteners  12   a ,  12   b ,  12   c  are fed into drive bore  38 , where fasteners  12   a ,  12   b ,  12   c  are driven by driver blade  32 . Magazine  42  feeds fasteners  12   a ,  12   b ,  12   c  so that they are aligned properly with loading opening  40  and with drive bore  38 . Magazine  42  includes a housing  62  configured to receive a collation  64   a ,  64   b ,  64   c  of collated fasteners  12   a ,  12   b ,  12   c , described below. In one embodiment, magazine housing  62  is mounted to handle  46  and includes a feed end  66  with a slot-like opening through which collations  64   a ,  64   b ,  64   c  are inserted, an exit end  68  having an exit opening which is in alignment or registry with loading opening  40  to allow free and sequential passage of fasteners  12   a ,  12   b ,  12   c  and sleeves  58  through the exit opening and loading opening  40 , and into drive bore  38 . A spring biased follower (not shown) pushes collation  64   a ,  64   b ,  64   c  of fasteners through magazine  42  toward exit opening  70 . Magazine  42  described herein is designed primary to address operational characteristics of fastener collation  64   a ,  64   b ,  64   c , which is described below.  
      Magazine  42  includes guidance means that extend between feed end  66  and exit end  68 , which preferably is provided with at least two guidance formations, a first guidance formation  100  configured for engaging fastener collation  64   a ,  64   b ,  64   c  at a first location on collation  64   a ,  64   b ,  64   c , and a second guidance formation  102  configured for engaging collation  64   a ,  64   b ,  64   c  at a second location on collation  64   a ,  64   b ,  64   c.    
      Magazine  42  facilitates loading of collations  64   a ,  64   b ,  64   c  so that they do not become caught or jammed in magazine  42 , and guiding collation  64   a ,  64   b ,  64   c  to loading opening  40 . In this way, magazine  42  defines a feed passageway  104  which extends the full length of magazine  42  from feed end  66  to exit end  68 . A first guidance zone  106 , which includes first guidance formation  100 , begins at feed end  66  and is configured for engaging collation  64   a ,  64   b ,  64   c  at front sleeve ends  74 .  
      3.1 First Guidance Formation  
      As shown in  FIG. 4 , in one embodiment, first guidance formation  100  in magazine  42  includes a feed passageway  104  having a collation channel  116   a  for accommodating sleeves  58  and a head channel  116   b  spaced from collation channel  116   a  for accommodating heads  16   a ,  16   b ,  16   c  of fasteners  12   a ,  12   b ,  12   c  having a particular fastener length FL. For example, lower head channel  116   b , shown in  FIG. 4 , is positioned to accommodate head  16   b  of medium fastener  12   b . Additional head channels may be included for heads of fasteners having other lengths, such as head channel  116   c  for heads  16   c  of long fasteners  12   c.    
      First guidance formation includes a pair of shoulders  110  that project laterally into feed passageway  104  to provide a track for front sleeve ends  74 . Front sleeve ends  74  slidably ride on shoulders  110  while fastener tip  18   a ,  18   b ,  18   c  extends axially between shoulders  110  into a tip channel  112  of feed passageway  104 . As described above, it may be desirable to have fastener tip  18   a ,  18   b ,  18   c  be flush with front end  74  or recessed within sleeve bore  76 . In this case, a pair of shoulders may not be necessary, but instead a single guidance surface extending across the lower end of feed passageway  104  that supports front sleeve end  74  may be used. The alignment of collation  64   a ,  64   b ,  64   c  is maintained by the spacing between shoulders  110 , which allows limited lateral movement of fasteners  12   a ,  12   b ,  12   c , and hence limited lateral movement of collation  64   a ,  64   b ,  64   c.    
      In one embodiment, shown in  FIG. 4 , strip passageway  104  at first guidance formation  100  includes a collation channel  116   a , a tip channel  112 , a first head channel  116   b  and a second head channel  116   c . The pair of shoulders  110  are at a forward end  117  of collation channel  116   a  and collation channel  116   a  extends rearwardly from forward end  117  far enough to accommodate sleeve  58 . Tip channel  112  protrudes forwardly from forward end  117  of collation channel  116   a . First head channel  116   b  is spaced rearwardly from collation channel  116   a  by a first rail  114   a , wherein first head channel  116   b  accommodates head  16   b  of medium fastener  12   b , but not head  16   a  of short fastener  12   a  or head  16   c  of long fastener  12   c . Second head channel  116   b  is spaced rearwardly from first head channel  116   a  by a second rail  114   b , wherein second head channel  116   b  accommodates head  16   c  of long fastener  12   c , but not head  16   a  of short fastener  12   a  or head  16   b  of medium fastener  12   b . In one embodiment, collation channel  116   a  is long enough to accommodate sleeve  58  and head  16   a  of short fastener  12   a , but is not long enough to accommodate heads  16   b ,  16   c  of medium or long fasteners  12   b ,  12   c . Channels  116   a ,  116   b ,  116   c  are each sized to accommodate a range of fastener lengths FL, and to allow for a manufacturing tolerance when placing fasteners  12   a ,  12   b ,  12   c  into sleeves  58 . Head channels  116   b ,  116   c  are shorter than sleeve  58  so that a user cannot accidentally place sleeve  58  in either head channels  116   b ,  116   c , which may cause collation  64   a ,  64   b ,  64   c  to be located in the wrong position when passing into second guidance zone  108  and loading opening  40 , but rather only in collation channel  116   a.    
      Preferably, shoulders  110  extend toward feed end  66  of magazine  42  farther than rails  114   a ,  114   b , as shown in  FIG. 1 , so that a user may easily load collation  64   a ,  64   b ,  64   c  properly by placing fastener tip  18   a ,  18   b ,  18   c  into tip channel  112  and ensuring that front sleeve ends  74  are abutted against shoulders  110 , and then sliding collation  64   a ,  64   b ,  64   c  along magazine  42  toward exit end  68  until fastener heads  16   a ,  16   b ,  16   c  are inserted into the appropriate channel  116   a ,  116   b  or  116   c . In this way, shoulders  110  provide a frame of reference for the user as to where to place collation  64   a ,  64   b ,  64   c.    
      3.2 Second Guidance Formation  
      Turning to  FIG. 5 , second guidance zone  108  in magazine  42  provides second guidance formation  102 . In a preferred embodiment, second guidance formation includes a pair of rails  86  engaged with channels  92  of sleeves  58  so that projections  82 ,  84  engage rails  86 . Second guidance zone  108  begins adjacent to first guidance zone  106  and extends substantially to exit end  68  of magazine  42  so that second guidance zone  108  accepts fasteners from first guidance zone  106 , as shown in  FIG. 1 . Rails  86  extend laterally into strip passageway  104  so that the distance between rails  86  is smaller than the diameter of upper collars  78  and lower collars  80  so that rails  86  engage projections  82 ,  84 . Rails  86  are spaced from each other to permit free slidability of collation  64   a ,  64   b ,  64   c  lengthwise along strip passageway  104 , but only permitting slight lateral movement of collation  64   a ,  64   b ,  64   c . Rails  86  have a thickness that is slightly smaller than the distance between upper projections  82  and lower projections  84  so that protrusions engage rails  86  along the length of magazine  42  to ensure that sleeves  58  and fasteners are properly aligned with loading opening  40 . Because rails  86  are engaged between projections  82 ,  84 , this alignment is maintained even when tool is used in an inverted position, so that collation  64   a ,  64   b ,  64   c  does not shift out of alignment in strip passageway  104 . Projections  82 ,  84  engage rails  86  of magazine  42  so that along a portion of magazine  42  only sleeves  58  are in contact with rails  86 . It has been found that when only a small portion of collation sleeves  58 , such as projections  82 ,  84  described above, are in contact with rails  86  as collation  64   a ,  64   b ,  64   c  slides along magazine  42 , there is less friction and collation  64   a ,  64   b ,  64   c  more easily slides along magazine  42 , preventing collation  64   a ,  64   b ,  64   c  from becoming retarded, “hung-up,” or jammed within magazine.  
      In one embodiment, shown in  FIG. 1 , first guidance zone  106  overlaps with second guidance zone  108  to form a transition zone  118  where both shoulders  110  and rails  86  briefly engage collation  64   a ,  64   b ,  64   c  to ensure that collation  64   a ,  64   b ,  64   c  has a smooth transition from first guidance zone  106  to second guidance zone  108  so that sleeves  58  do not become hung up on rails  86 . In this way, first guidance zone  106  and second guidance zone  108  act in cooperation to ensure that collations  64   a ,  64   b ,  64   c  of fasteners  12   a ,  12   b ,  12   c  are properly loaded into magazine  42  and to ensure that collations  64   a ,  64   b ,  64   c  are properly aligned with loading opening  40 .  
      4 Loading Opening  
      Turning now to  FIG. 3 , as described above, preferably, tool  10  is designed to accommodate different collations  10   a ,  10   b ,  10   c  and fasteners  12   a ,  12   b ,  12   c  of different lengths FL for use in different applications. Therefore, preferably, fastener driving tool  10  is designed to accommodate the different fastener lengths FL associated with the fasteners of the different collations. For this purpose, magazine  42  and loading opening  40  must be axially long enough to accommodate the longest fasteners  12   a ,  12   b ,  12   c  that are to be driven by tool  10 .  
      Collations  64   a ,  64   b ,  64   c  may have a substantially uniform exposed tip length TL of fasteners  12   a ,  12   b ,  12   c , regardless of the length FL of fastener  12   a ,  12   b ,  12   c  being used. Uniform exposed tip length TL only requires loading opening  40  to be long enough below sleeve  58  to allow fastener tips  18   a ,  18   b ,  18   c  to pass through loading opening  40 . Therefore, loading opening  40  accommodates heads  16   a ,  16   b ,  16   c  of fasteners  12   a ,  12   b ,  12   c  having various lengths by being long enough above collation sleeves  58  to allow for fastener heads  16   a ,  16   b ,  16   c  located at different positions relative to sleeves  58 . The length of the channel  124  of loading opening  40  that accommodates tip  18   a ,  18   b ,  18   c  only needs to be long enough to allow the uniform length of fastener tips  18   a ,  18   b ,  18   c  that extend below lower end of collation sleeve  58 , which effectively eliminates the exit of short fastener tips  18   a  so that they may be prevented from diving back into magazine  42 .  
      Continuing with  FIG. 3 , loading opening  40  includes a main channel  120  for accommodating sleeves  58  and fastener heads  16   a ,  16   b ,  16   c , and a tip channel  124  protruding forwardly from a forward end  122  of main channel  120  for accommodating fastener tips  18   a ,  18   b ,  18   c . There is a pair of shoulders  126  at forward end  122  of main channel  120  for guiding front sleeve ends  74 . Shoulders  126  support front end  74  of the second sleeve  58 , shown in  FIGS. 6 and 7 , as the leading fastener  12   a ,  12   b ,  12   c  and the leading sleeve  58  are driven to ensure that there is a clean break between the leading sleeve  58  and the second sleeve  58 . Shoulders  126  are substantially aligned with shoulders  110  of first guidance zone  106  in magazine  42 .  
      4.1 Tip Channel of Loading Opening  
      Continuing with  FIG. 3 , tip channel  124  protrudes from main channel  120  for a predetermined tip channel depth TCD from shoulders  126 , wherein the predetermined tip channel depth TCD is slightly larger than the uniform exposed tip length TL so that there is a small clearance between a forward end  128  of tip channel  124  and fastener tips  18   a ,  18   b ,  18   c , allowing fastener tips  18   a ,  18   b ,  18   c  to pass through tip channel  124 . Tip channel  124  has a shape that substantially corresponds to the profile of ogive  19   a ,  19   b ,  19   c . In one embodiment, fasteners  12   a ,  12   b ,  12   c  have generally conical ogives  19   a ,  19   b ,  19   c , and tip channel  124  is generally parabolic, as shown in  FIG. 3 , however, tip channel  124  may have a pointed shape that substantially matches the conical shape of ogive  19   a ,  19   b ,  19   c . Main channel  120  of loading opening  40  is long enough to accommodate the longest fasteners  12   a ,  12   b ,  12   c  that are intended to be driven by tool  10 .  
      Uniform exposed tip length TL of fasteners  12   a ,  12   b ,  12   c , along with tip channel depth TCD of tip channel  124  of loading opening  40 , allow tool  10  to discourage dive back of fasteners  12   a ,  12   b ,  12   c  into magazine  42  because fastener tips  18   a ,  18   b ,  18   c  do not have enough space or time to angle toward magazine  42  to pass back through loading opening  40 . Even if fastener tip  18   a ,  18   b ,  18   c  starts to dive back toward magazine  42 , it is redirected by drive bore  38  toward work surface  6 .  
      In one embodiment, the depth TCD of tip channel  124  in loading opening  40  is larger than the uniform exposed tip length TL, but tip channel depth TCD should be as close to the uniform exposed tip length TL as possible to ensure that there is not enough space to form an exit for fastener tips  18   a ,  18   b ,  18   c . In one embodiment, tip channel depth TCD is longer than the uniform exposed tip length TL by just enough to account for the expected manufacturing tolerance of the positioning of fastener tips  18   a ,  18   b ,  18   c . In one embodiment, fasteners  12   a ,  12   b ,  12   c  may be inserted into sleeves  58  so that the exposed tip length TL is within about 0.025 inch of the desired uniform exposed tip length TL. For example, if the desired uniform exposed tip length TL is about 0.205 inch, than during manufacturing of collations  64   a ,  64   b ,  64   c , fastener tips  18   a ,  18   b ,  18   c  should be placed between about 0.18 inch and about 0.23 inch from front sleeve ends  74 . Therefore, in order to accommodate fasteners tips  18   a ,  18   b ,  18   c  in a collation  64   a ,  64   b ,  64   c  where the desired uniform exposed tip length TL is 0.205 inch, the predetermined channel depth TCD of tip channel  124  is preferably slightly larger than about 0.23 inch, e.g. about 0.235 inch, to ensure that tip channel  124  is longer than the longest expected exposed tip length TL while still having a close clearance between fastener tip  18   a ,  18   b ,  18   c  and forward end  128  of tip channel  124 .  
      The predetermined channel depth TCD of tip channel  124  is preferably between about 0 inch, i.e. so that tip channel  124  and main channel  120  are one and the same for the situation where fastener tips  18   a ,  18   b ,  18   c  are flush with front sleeve ends  74  or recessed within bore  76 , and about 0.55 inch, more preferably between about 0.15 inch and about 0.275 inch, still more preferably about 0.235 inch. Because of the importance of the close clearance between fastener tips  18   a ,  18   b ,  18   c  and loading opening  40 , it is important that the manufacturing tolerance of exposed tip length TL be tightly controlled because the smaller the manufacturing tolerance, the closer the clearance between fastener tip  18   a ,  18   b ,  18   c  and loading opening  40  is, the less likely that fastener tips  18   a ,  18   b ,  18   c  will dive back through loading opening  40 .  
      4.2 Main Channel of Loading Opening  
      Continuing with  FIG. 3 , main channel  120  of loading opening  40  may have a generally rectangular shape so that sleeves  58  and fastener heads  16   a ,  16   b ,  16   c  fit through opening, however, preferably the shape of loading opening  40  is selected to correspond to the profile of collation  64   a ,  64   b ,  64   c  so that fasteners  12   a ,  12   b ,  12   c  and sleeves  58  sequentially fit through loading opening  40  only if they have the proper orientation. In one embodiment, main channel  120  of loading opening  40  is demarcated into a front channel  132  and a rear channel  134  by a pair of rails  130  that is axially spaced from shoulders  126 , wherein rails  130  protrude into loading opening  40  for engaging the protrusions of sleeve  58 , such as projections  82 ,  84 , similar to how rails  86  in magazine  42  are engaged by projections  82 ,  84 .  
      Rails  130  are aligned with rails  86  so that as magazine  42  feeds fasteners  12   a ,  12   b ,  12   c  and sleeves  58  to loading opening  40 , collation  64   a ,  64   b ,  64   c  remains properly positioned with respect to loading opening  40  so that collation  64   a ,  64   b ,  64   c  is not hung up and so that fastener tips  18   a ,  18   b ,  18   c  are positioned properly with respect to tip channel  124  of loading opening  40 . In addition to engaging projections  82 ,  84 , rails  130  may also protrude laterally inwardly far enough so that they engage fastener shank  14   a ,  14   b ,  14   c  within a close clearance in order to further axially align fastener  12   a ,  12   b ,  12   c.    
      As with shoulders  126  supporting front end  74  of second sleeve  58   b , rails  130  support the second sleeve  58  by engaging and supporting projections  82 ,  84  so that the leading sleeve  58  is cleanly sheared as the leading fastener  12   a ,  12   b ,  12   c  is driven. Because rails  130  are engaged between projections  82 ,  84 , they support the second sleeve  58  even when tool  10  is used in an inverted position.  
      Like rails  86  of magazine  42 , preferably rails  130  have a thickness that is approximately equal to the distance between projections  82 ,  84 , within a small clearance, so that the second sleeve  58  is prevented from skewing upwardly or downwardly. In one embodiment, wherein the distance between upper projections  82  and lower projections  84  is about 0.097 inch, the thickness of rails  130  is about 0.091 inch, so that there is an average clearance of about 0.003 inch on either side between rails  130  and projections  82 ,  84 .  
      As shown in  FIG. 3 , main channel  120  of loading opening  40  may also include additional rails  136   a ,  136   b  that further demarcate main channel  120  into additional channels for receiving fastener head  16   a ,  16   b ,  16   c . In one embodiment, main channel  120  further includes a pair of rails  136   a  spaced rearwardly from rails  130 , there being a first head channel  137   a  rearwardly of rails  136   a  for accommodating the head  16   b  of medium fastener  12   b , and a second head channel  137   b  spaced rearwardly from first head channel  137   a  by another pair of rails  136   b , wherein second head channel  137   b  accommodates the head  16   c  of long fastener  12   c . In one embodiment, upper collar  78  and head  16   a  of short fastener  12   a  is accommodated between rails  130  and rails  136   a . Preferably, rails  136   a ,  136   b  only engage fastener shank  14   a ,  14   b ,  14   c , and not fastener head  16   a ,  16   b ,  16   c , to prevent hang-ups of collation  64   a ,  64   b ,  64   c  through loading opening  40 . However, rails  136   a ,  136   b  may be positioned to support fastener heads  16   b ,  16   c  if desired.  
      As described above, preferably loading opening  40  is located though shear block  60 . In one embodiment, shear block  60  has a thickness ST, so that shoulders  126 , and rails  130 ,  136   a , and  136   b  have a length through shear block  60  so that shoulders  126  and rails  130  support a substantial portion of second sleeve  58 , and preferably all of second sleeve  58 , still more preferably all of second sleeve  58  and a substantial portion of a third sleeve  58  (see  FIGS. 6 and 7 ) so that the remainder of collation  64   a ,  64   b ,  64   c  that is not being driven is adequately supported so that when leading fastener  12   a ,  12   b ,  12   c  is driven, there is a clear break between leading sleeve  58  and second sleeve  58 . Preferably, the side of loading opening  40  that faces into drive bore  38  is substantially aligned with breaking plane  98  between leading sleeve  58  and second sleeve  58  to further ensure a clean break. The thickness of shear block  60  also allows rails  130 ,  136   a , and  136   b  to engage substantially all of shank  14   a ,  14   b ,  14   c  second fastener  12   a ,  12   b ,  12   c , and preferably at least a portion of shank  14   a ,  14   b ,  14   c  of third fastener  12   a ,  12   b ,  12   c . In one embodiment, shear block  60  has a predetermined thickness ST of between about ¼ inch and about ¾ inch, preferably between about ⅜ inch and about ⅝ inch, still more preferably about 0.59 inch, and shoulders  126  and rails  130 ,  136   a , and  136   b  have a length that is substantially equal to the thickness ST of shear block  60 .  
      5 Fastener Guide  
      Turning back to  FIGS. 6 and 7 , tool includes a telescoping fastener guide  44  for guiding fasteners  12   a ,  12   b ,  12   c  and sleeves  58  toward work piece  4  and substrate  2  as they are driven by driver blade  32 . Fastener guide  44  receives the leading fastener  12   a ,  12   b ,  12   c  and sleeve  58  as they are driven from nosepiece  36  and shear block  60  and continues to guide leading fastener  12   a ,  12   b ,  12   c  and sleeve  58  toward work surface  6 . Fastener guide  44  is coaxial with drive bore  38  so that as leading fastener  12   a ,  12   b ,  12   c  is driven axially forwardly, it will encounter and be guided by fastener guide  44 . As described above, fasteners  12   a ,  12   b ,  12   c  are fed into drive bore  38  so that they are coaxially aligned with drive bore  38 , so that fasteners  12   a ,  12   b ,  12   c  also are coaxially aligned with fastener guide  44 .  
      In one embodiment, fastener guide  44  is generally cylindrical in shape with a generally cylindrical bore  138  extending through fastener guide  44  between a rear end  140  and a front end  144 . Fastener guide bore  138  includes a portion  142  at rear end  140  of fastener guide  44  that is tapered toward axis  28  to guide a driven fastener  12   a ,  12   b ,  12   c  toward bore  138  in the event that fastener tip  18   a ,  18   b ,  18   c  becomes angled away from axis  28  of tool. Bore  138  may also include a tapered portion  146  at front end  144  in order to provide space for portions of sleeve  58  that split away from fastener  12   a ,  12   b ,  12   c  as fastener  12   a ,  12   b ,  12   c  is driven into work piece  4  and substrate  2 .  
      Fastener guide  44  is movable between an extended position, shown in  FIG. 6 , and a retracted position, shown in  FIG. 7 , relative to nosepiece  36 , shear block  60 , and tool body  20 , wherein fastener guide  44  is moved from the extended position to the retracted position when fastener guide  44  is abutted against work piece  4 . When tool  10  is fired, a reactionary force is created in tool body  20  that causes tool body  20  to recoil away from work piece  4  and substrate  2 . Nosepiece  36 , shear block  60 , and magazine  42  are operatively connected to tool body  20 , so that when tool body recoils, so does nosepiece  36 , shear block  60 , and magazine  42 . If fastener guide  44  were also to recoil along with nosepiece  36  and shear block  60 , then nosepiece will lift off work piece  4  so that when fastener  12   a ,  12   b ,  12   c  exited fastener guide  44 , it may be in free flight before it entered work piece  4  and substrate  2 , which may cause fastener  12   a ,  12   b ,  12   c  to be driven at an undesired position, or misalignment of fastener  12   a ,  12   b ,  12   c  with respect to work piece  4 , so that fastener may break, shear, or ricochet rather than drive cleanly through work piece  4  and substrate  2 .  
      For this reason, fastener guide  44  is configured so that it remains in abutment with work piece  4  when tool body  20  and nosepiece  36  recoil due to firing of tool  10 . Fastener guide  44  is free to move independent of nosepiece  36  and shear block between the extended position and the retracted position, so that as nosepiece  36  recoils, fastener guide  44  is moved from the retracted position to the extended position. A spring (not shown) may also be included to bias fastener guide  44  toward the extended position to ensure that fastener guide  44  does not recoil as tool body recoils, but rather remains abutted against work piece  4 .  
      Because fastener guide  44  is separate from nosepiece  36  and shear block  60 , and because fastener guide  44  moves independently of nosepiece  36  and shear block  60  as fastener guide  44  moves from the extended position to the retracted position, tool  10  has a loading opening  40  that is stationary with respect to magazine  42  so that there is a fixed loading position of fasteners  12   a ,  12   b ,  12   c  with respect to subsequent collations  64   a ,  64   b ,  64   c . A fixed loading position with respect to magazine  42  allows a user to push fastener guide  44  against work surface  6  multiple times before firing without moving the leading fastener  12   a ,  12   b ,  12   c  and sleeve  58  up or down within drive bore  38 , so that there is reduced risk of the second fastener  12   a ,  12   b ,  12   c  being loaded into drive bore  38  before the leading fastener  12   a ,  12   b ,  12   c  is driven.  
      Continuing with  FIGS. 1, 2 ,  6  and  7 , fastener guide  44  is operatively connected to the power source so that the power source is activated when fastener guide  44  is placed in abutment with work surface  6  and moved into the retracted position. In one embodiment, fastener guide  44  is operatively connected to combustion chamber sleeve  50  via an actuator  148  and a link  150  so that when fastener guide  44  is in the extended position with respect to nosepiece  36 , combustion chamber sleeve  50  is in the open position, and when fastener guide  44  is pushed against work surface  6  and moved into the retracted position, combustion chamber sleeve  50  is pushed into the closed position, so that combustion chamber  34  is activated when fastener guide  44  is pushed against work surface  6 . As tool body  20  recoils due to the firing of tool  10 , combustion chamber sleeve  50  remains operatively connected to fastener guide  44  so that combustion chamber sleeve  50  is moved from the closed position into the open position so that tool  10  will not be able to be fired again until fastener guide  44  is pushed into the retracted position again.  
      Continuing with  FIGS. 6 and 7 , fastener guide  44  is preferably generally cylindrical in shape so that fastener guide  44  may be mounted with nosepiece  36  and shear block  60 . In one embodiment, fastener guide  44  is mounted radially within a forward end  39  of drive bore  38 , with forward end  144  of fastener guide  44  extending out of drive bore  38 . In one embodiment, fastener guide  44  is also mounted within a generally cylindrical actuator  148 , wherein forward end  144  of fastener guide  44  extends out of actuator  148  as well. Fastener guide  44  includes a radially outwardly protruding flange  152  that engages actuator  148  when fastener guide  44  is pushed into the retracted position so that flange  152  pushes actuator  148  rearwardly with respect to tool body  20 . Actuator  148 , in turn, is connected to a link  150 , which is operatively connected to combustion chamber sleeve  50 , so that as actuator  148  is pushed rearwardly by fastener guide  44 , it pushes link  150  rearwardly, which pushes combustion chamber sleeve  50  rearwardly into the closed position, activating combustion chamber  34  allowing tool  10  to be fired.  
      Fastener guide  44  may be slidably mounted to nosepiece  36  or shear block  60  so that fastener guide  44  does not fall out of engagement with tool  10 . In one embodiment, fastener guide  44  includes an axially extending groove  154  that extends for a predetermined distance along the outside surface  156  of fastener guide  44 , wherein groove  154  accepts a key  158  of shear block  60  that is inserted into groove  154  when shear block  60  is mounted to nosepiece  36 . When fastener guide  44  is in the extended position, key  158  is positioned so that it engages rear end  160  of groove  154 , as shown in  FIG. 6 . When fastener guide  44  is moved to the retracted position, key  158  slides along groove  154  until key  158  is positioned at a front end  162  of groove  154  so that key engages front end  162 , as shown in  FIG. 7 .  
      6 Collation and Tool System  
      A system for fastening a work piece  4  to a substrate  2  is provided, wherein the system includes a first collation  64   a  having a plurality of sleeves  58  holding fasteners  12   a  each having a predetermined exposed tip length TL, a second collation  64   b  having a plurality of sleeves  58  holding fasteners  12   b  each having substantially the same predetermined exposed tip length TL, wherein fasteners  12   b  are of different length FL than fasteners  12   a . Fastener driving tool  10  includes a tool body  20  having a forward end  22 , a rear end  24 , and a cylinder  26  with an axis  28 . A piston  30  is mounted within cylinder  26 , and a power source, such as combustion chamber  34  for combusting fuel, is provided to drive piston  30  axially forwardly. A driver blade  32  extends axially forwardly from piston  30 , and a nosepiece  36  extends axially forwardly from forward end  22  of tool body  20 . Nosepiece  36  encloses a drive bore  38  for guiding fasteners  12   a  and driver blade  32  forwardly, wherein there is a loading opening  40  into drive bore  38 , wherein loading opening  40  has a main channel  120  and a tip channel  124  having a depth TCD that is slightly larger than the exposed tip length TL so that there is a small clearance though which the tips  18   a  can pass.  
      The system my further include a third collation  64   c  with sleeves  58  holding fasteners  12   c , wherein fasteners  12   b  also have tips  18   b  with substantially the same predetermined exposed tip length TL as collations  64   a  and  64   c  so that the clearance of tip channel  124  is large enough for tips  18   b  also. Fasteners  12   c  of third collation  64   c  are of different length than fasteners  12   a  and  12   b    
      A system of collations  64   a ,  64   b ,  64   c  having fasteners  12   a ,  12   b ,  12   c  of different lengths FL, but with substantially the same exposed tip length TL, along with tool  10  having loading opening  40  with tip channel  124  having a depth that is slightly larger than the predetermined exposed tip length TL, allows a user of the system to have the tool and fasteners that are needed for various applications that are readily available. For example, a user may need short fasteners  12   a  ( FIG. 8A ) for attaching thin metal tracks  4  to hard substrates  2 , such as concrete or steel, and longer fasteners, e.g., medium fasteners  12   b  ( FIG. 8B ), for attaching plywood work pieces to concrete or steel substrates, then the system of collations  64   a  of short fasteners  12   a , collations  64   b  of medium fasteners  12   b , and fastener driving tool  10  may be provided to the user, and the user may simply select the appropriate collation  64   a ,  64   b  having the appropriate length FL fastener  12   a ,  12   b  for whichever application the user is currently working on. The system may include collations  64   c  of long fasteners  12   c  (see  FIG. 8C ), which may be used by the user for thicker work pieces, or additional holding strength.  
      7 Method of Selecting and Driving Fastener  
      A method of selecting and driving a fastener  12   a ,  12   b ,  12   c  for a particular application is provided comprising the steps of providing a first collation  64   a  of a plurality of sleeves  58  holding first fasteners, such as short fasteners  12   a  each having a tip  18   a  with a predetermined exposed tip length TL below front sleeve end  74 , providing a second collation  64   c  of a plurality of sleeves  58  each holding a corresponding second fastener, such as long fasteners  12   c  each having a tip  18   c  with substantially the same predetermined exposed tip length TL below front end  74 , wherein fasteners  12   c  are longer than fasteners  12   a , wherein short fasteners  12   a  and long fasteners  12   c  are adapted to be serially and individually driven through drive bore  38  of fastener driving tool  10  by a drive member, such as driver blade  32 , so as to be discharged from tool  10 , there being a loading opening  40  into drive bore  38  having a main channel  120  and a tip channel  124  providing a small clearance through which tips  18   a  or tips  18   c  can pass, the main channel  120  of loading opening  40  being long enough to accommodate short fasteners  12   a  and long fasteners  12   c , selecting one of first collation  64   a  or second collation  64   c  for the desired length FL of fastener  12   a ,  12   c  for a particular application (i.e. short fastener  12   a  for a thin work piece  4 , long fastener  12   c  for a thick plywood work piece), feeding the fasteners  12   a ,  12   c  of the selected collation  64   a ,  64   c  through loading opening  40 , and driving the fasteners  12   a ,  12   c  of the selected collation  64   a ,  64   c  with driver blade  32 .  
      The method also may include the step of providing a third collation  64   b  of a plurality of sleeves  58  each holding a third fastener, such as medium fastener  12   b  having a tip  18   b  with substantially the same predetermined exposed tip length TL below front end  74 , wherein fastener  12   b  is longer than short fasteners  12   a , but shorter than long fasteners  12   c . This method also includes the step of selecting any one of the first collation  64   a  of short fasteners  12   a , the second collation  64   b  of medium fasteners  12   b , or the third collation  64   c  of long fasteners  12   c , and feeding the fasteners  12   a ,  12   b ,  12   c  of the selected collation  64   a ,  64   b ,  64   c  to drive bore  38 .  
      In one aspect, the method includes a step of determining which of the short fasteners  12   a , medium fasteners  12   b , or long fasteners  12   c  should be used for a particular application. This determining step may be determined by experimentation, experience, or professional judgment on the part of the user of tool  10 . For example, it has been learned through previous testing that long fastener  12   c  having a fastener length FL of about 1 inch may not be ideal for fastening a thin metal work piece  4 , like metal tracking, to a hard substrate  2 , such as concrete or steel, as described above, so that short fastener  12   a  having a length FL of about ½ inch may be preferred. In contrast, short fastener  12   a  may not be long enough to extend through a thicker work piece, such as a ¾ inch thick plywood substrate, so that long fastener  12   c  may be preferred for the latter application.  
      In summary, a fastener driving tool according to the present invention allows a user to drive fasteners of various lengths while reducing the risk of shorter fasteners diving back into the magazine and jamming or damaging the tool, while improving guidance of longer fasteners. The tool may provide a telescoping nosepiece that remains abutted against the work surface when the rest of the tool recoils due to the firing of the tool while providing a fixed loading position. Collations according to the present invention allow fasteners of various lengths to be driven by a fastener driving tool while reducing the risk of shorter fasteners diving back into the magazine and jamming or damaging the tool.  
      While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific exemplary embodiment and method herein. The invention should therefore not be limited by the above described embodiment and method, but by all embodiments and methods within the scope and spirit of the invention as claimed.