Abstract:
A fastener system for use with a powder actuated tool. The system include a pin, a metallic washer surrounding a portion of the pin at the second end; and a plastic sleeve disposed between the metallic washer and the pin. The plastic sleeve includes a cap portion and an sleeve portion, the cap portion disposed on the top side of the metallic washer coincident with the head of the pin.

Description:
PRIORITY CLAIM 
     This application claims the benefit of U.S. Provisional Application No. 60/896,155, filed on Mar. 21, 2007, entitled “Sleeve Protected Fastener,” having inventor William D. Georges. 
    
    
     BACKGROUND 
     Pressure-treated wood is truly a rugged exterior building product that is rot and insect resistant. Treated wood is used for a number of exterior building applications. Pressure treatment is a process that forces chemical preservatives into the wood. Wood is placed inside a closed cylinder, and vacuum and pressure are applied to force the preservatives into the wood. The preservatives help protect the wood from attack by termites, other insects, and fungal decay. 
     Hot-dip galvanized or stainless steel fasteners, anchors and hardware are recommended by the Pressure Treated Wood Industry for use with treated wood. This prevents the fasteners from decaying faster than the wood itself. In the past this industry did not address the required levels of galvanizing, however most of those in the industry now provide information regarding the minimum level of galvanizing that should be used. 
     In general, the thicker the galvanized coating the longer the expected service life of the fastener, connector, anchor, or other hardware will be. Mechanical galvanizing is a process of providing a protective coating (zinc) over bare steel. The bare steel is cleaned and loaded into a tumbler containing non-metallic impact beads and zinc powder. As the tumbler is spun, the zinc powder mechanically adheres to the parts. The zinc coating has “good” durability, but has less abrasion resistance than hot-dip galvanized zinc coatings since it does not metalurgically bond with the steel. Some anchors and fasteners can be mechanically galvanized. 
     An alternative to mechanical galvanizing is hot-dip galvanizing Hot-dip galvanizing is the process of coating iron or steel with a thin zinc layer, by passing the steel through a molten bath of zinc at a temperature of around 460° C. In general, a heavier/thicker coating would be expected to have a longer service life than standard galvanized connectors. 
     Typically, pin and washer combinations are used as fastener systems in powder actuated fastening devices. Commonly known as Powder Actuated Tools, these devices force a pin through a washer into the wood with sufficient force to embed the pin in a single stroke. Typically, a fastener is initially coupled to a metallic washer with a through-hole having a diameter smaller than the diameter of a fastener. This ensures that the pin and washer stay in place when loaded in to the fastening device, and are secure when the device is forced downward (toward the wood), typically to deactivate a safety device present in the tool which prevents accidental firing of the fastener. When used with standard applications of washers having a through-hole with a diameter smaller than the diameter of a fastener, the washer can scratch off a galvanized coating, eliminating or reducing the benefits of the zinc layer. 
     SUMMARY 
     In one embodiment, a fastener system for use with a powder actuated tool includes a fastener including a shaft having a first end including a head and second end including a point. A metallic washer surrounds a portion of the fastener at the second end; and a plastic sleeve is disposed between the metallic washer and a shaft of the fastener. The plastic sleeve includes a cap portion and a sleeve portion, the cap portion exposed on the top side of the metallic washer, the sleeve extending through the washer. 
     In addition, a method of assembling a fastening system is disclosed. The method includes providing a fastener having a first end and a second end defining a length and providing a metallic washer having a bore. A plastic sleeve is inserted into the bore in the washer. The sleeve has an outer diameter sized to fit within the bore. Next, the fastener is inserted into the second end of the sleeve toward the first end. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a prior art fastener and washer combination. 
         FIG. 2  is a perspective view of a fastener provided in accordance with the present technology. 
         FIG. 3A  is a plan view of the fastener of the present technology. 
         FIG. 3B  is a second plan view of the fastener of  FIG. 3A . 
         FIG. 4  is a view along line  44  in  FIG. 3 . 
         FIG. 5  is a view along line  55  in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a prior art pin and washer combination. A pin  10  includes a shaft  15  and a point  30  and a diameter D 1 . Washer  20  includes a through hole  25  having a diameter D 2  slightly smaller than diameter D 1 . The diameter D 2  is designed so that the through hole  25  will engage shaft  15  after passing over point  30  to establish a friction fit between the washer  20  and shaft  15  allowing both the pin  10  and washer  20  to be loaded into a powder actuated tool. With thinner zinc coatings, the difference in diameters D 2  and D 1  was not significant enough to remove the coating from the pin  10 . However, with thicker coatings, this type of fastener results in coating being scrapped off of the shaft  15  as a washer slides up the shaft. This can compromise the integrity of the fastener and cause the fastener to fail. 
       FIGS. 2-5  illustrate a fastener system  100  created in accordance with the present technology. Fastener  100  includes a pin  130  having a shaft  115  and head  110 . Head  110  is provided at a first end of shaft  115  and a tip  125  is provided at a second end  120  of shaft  115 . Illustrated in  FIG. 2  is a washer  150  having a through hole  225  through which a sleeve  200  made of a plastic material is provided. As illustrated in  FIGS. 3A and 3B , sleeve  200  includes a shaft  215  extending a length H and a cap portion  210  having a top surface  212  and bottom surface  214 . Washer  150  includes a top surface  202  and a bottom surface  204 . The bottom surface  214  of sleeve  200  abuts the top surface  202  of washer  150 . Shaft  215  of sleeve  200  has an inner diameter D 3  sized to surround fastener shaft  115  and further includes an outer diameter D 4  sized to match the inner diameter of through hole  225 . Also shown in  FIG. 2  is an adapter  135  commonly used on pre-assembled fasteners to align the fastener in the barrel of the tool. 
     In one embodiment, the parts are arranged as shown in  FIG. 3B  and the shaft  215  of sleeve  200  is first inserted through hole  225  in washer  150  until top surface  202  engages bottom surface  214  of the cap portion of sleeve  200 . Subsequently, the pin  100  is forced through the shaft from the cap portion to a position shown in  FIG. 3A . The diameter D 1  of the shaft  115  is somewhat larger than D 3 , inducing a friction fit between the through hole  225  and the shaft  215  positioned there through. This friction fit prevents movement of the washer  150  relative to the sleeve  200 . 
       FIG. 3A  illustrates an initial fastener position ready for insertion into a powder actuated tool.  FIG. 2  illustrates an extended fastener position with the pin extending through the sleeve, the sleeve  200  having slid up the shaft  115  to the position shown in  FIG. 2 . Sleeve  200  is comprised of plastic such that when a pin is extruded through the sleeve to the position shown in  FIG. 2 , no flaking of the coating on the pin occurs. 
     The fastener  100  is advantageously used with powder actuated tools. These tools may require a downward pressure be exerted by the operator against a loaded fastener positioned in the tool, with the fastener positioned against the surface into which it is to be inserted, in order to release a firing safety. Normally, with the fastener shown in  FIG. 1 , the force is exerted against the washer  20 . This is because the washer  20  is at or nearly adjacent to this surface in which the fastener is to be inserted. 
     In the fastener of  FIGS. 2-5 , force is exerted against the cap of sleeve  200 . In one embodiment, the length H of sleeve  215  is sized to adapt to the type of tool in which the fastener is being used. The sleeve allows pins of various sizes to be adapted to fit various powder actuated tools. For example, if a powder actuated tool is sized to fire two and one-half inch pins, the half inch length H of the sleeve can be utilized to effectively shorten the length of a three inch sleeve allowing the three inch fastener to be used in the two and a half inch tool. It would be readily recognized that all dimensions discussed herein, including the length H and diameters D 1 , D 2  and D 3  can all be adjusted accordingly. 
     Typically, fastener systems of the present design may be manufactured from mechanically galvanized carbon steel or stainless steel to have a galvanized coating thickness of 1.4-3.9 milli-inches, with shank lengths varying from 2-3″, and shank diameters (D 2 ) of 0.145-0.177 inch. mechanically galvanized carbon steel or stainless steel. Washer  150  may have a diameter of about 1″, but its size may vary as well. 
     Coatings applied to the fastener may be any of a number of commercially available coatings. Mechanical galvanization provides a protective zinc and tin coating over base metal. The coating is applied by mechanically tumbling zinc and tin powder with base metal and non-metallic impact beads. Still further, a coating system that combines a mechanically plated zinc undercoat with a thermosetting polyester top coat applied in multiple layers using dip-spin technology may be used. Mechanical galvanization coatings provide a protective zinc nickel alloy coating over base metal. The coating is applied by mechanically tumbling base metal with non-metallic impact beads and zinc powder. Alternatively, a duplex coating system which combines an electroplated zinc and chromate substrate with an organic top coat may be used. An electroplated zinc layer provides sacrificial protection of the steel substrate while the topcoat creates a durable barrier. Typical coating thickness is 8-10 microns top coat over 8 microns minimum zinc/chromate base coat. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.