WO1997044589A1

WO1997044589A1 - Staple fastener driver and filler apparatus

Info

Publication number: WO1997044589A1
Application number: PCT/US1997/009189
Authority: WO
Inventors: Kenneth Evensen
Original assignee: Kenneth Evensen
Priority date: 1996-05-24
Filing date: 1997-05-22
Publication date: 1997-11-27
Also published as: AU3220197A

Abstract

A power tool (210) and fasteners (212) filled with a filler material (218) are provided. The power tool (210) drives fasteners into a substrate and fills cavities formed in the substrate formed over the driven fasteners with a filler material. The power tool (210) is preferably a pneumatic gun having a staple driver (220) and a filler material driver (22) actuated by pressurized air. The gun includes a trigger operator (310) which when pulled first causes a staple (212) carrying filler material (218) therewith to be driven by a plunger (252) of the staple driver (220) through its shaft into the substrate with the filler material (218) extruding from the driven staple (212) into the shaft (288) of the filler material driver (222) which is next driven by a plunger (290) of the filler material driver (222) out from its shaft (288) and into the cavity (216) formed over the driven staple (212). A scraping shoe (230) can be provided adjacent the drivers for scraping away excess filler material (218) from the substrate surface (214a).

Description

STAPLE FASTENER DRIVER AND FILLER APPARATUS

Field of the Invention

The present invention relates to fasteners filled with a covering filler material and to a power tool for driving and for covering the fasteners with the filler material. The method and apparatus employ a powered gun adapted for driving fasteners such as staples into a substrate and for next driving filler material over the driven staple fasteners.

Background of the Invention

Fastener driving guns, such as power nailers and staplers, are known for driving fasteners into wood and other substrates. Some applications for which these power guns are particularly useful are for installing wood floor planks and wood trim molding in homes and buildings and for furniture making and repair. Heavy- duty guns and fasteners are available for use with thicker stock such as with cabinet bodies and large crown moldings. The longer heavy duty fasteners will also extend through drywall and into wall studs for attaching door and window casings and other architectural trim work. While the power tool herein is described in its preferred form as being a pneumatically-powered tool, it will be recognized by those skilled in the art that other forms are also contemplated by the present invention, such as an electrically powered tool.

With known staple guns, a strip of staples are attached to each other and are loaded in a staple cartridge of the gun. The staple cartridge feeds the strip of staples one staple at a time to a shaft of the staple driver of the gun. Depressing a trigger causes the gun to drive the staple in the staple driver down through the driver shaft and out from the bottom of the shaft and into the substrate therebelow. Typically, such guns drive staples so that they are recessed below the surface of the substrate.

Particularly where the fasteners are used in substrates that are exposed, it is desirable that the driven fasteners be hidden or concealed from view. In this regard, there are a wide variety of products available for filling such recesses or cavities formed over fasteners driven in substrates with a material which closely matches the look of the particular substrate being worked on. Typically, such products come in a stick or pencil form and require that the user manually rub the filler material into the cavity. Another product used to fill recesses is plastic wood, which has a solvent that evaporates, and the plastic wood then dries. After rubbing the material into the cavities, if any excess material remains, the user is required to subsequently remove the excess such as with fine steel wool or by scraping the surface with a scraping blade, putty knife, or the like. It is also known to load stick filler products in an extruder applicator, such as a caulking-type gun. Use of such an applicator requires the user to precisely position it over the recesses and to then manually squeeze the lever handle of the applicator to extrude the filler material from the applicator into the recesses for covering fasteners driven into the substrate. In any event, the process of driving staple fasteners into substrates and then subsequently covering them with filler material requires two separate and distinct operations and/or different tools and thus is both labor intensive and time consuming. Where the fasteners are used in finishing home and building interiors, the extra manual labor and time required for covering the driven fasteners is particularly undesirable, as this translates into higher labor costs increasing the overall cost of the project. Accordingly, there is a need for an apparatus and method which easily and quickly drives staple fasteners and covers them so they are concealed from view.

Summary of the Invention

In accordance with the present invention, a staple fastener having filler material between the leg portions thereof is driven into a substrate. The filler material extrudes out from between the staple legs and flows into the cavity formed above the driven staple. Where a strip of staples is provided for being loaded in a staple gun with each staple carrying filler material, it is important that the filler material be able to be sheared cleanly as it is driven with its associated staple away from the next adjacent staple in the strip and the filler material carried thereby. One typical filler material is a wax-based crayon-type of material that is relatively tacky and sticky and thus does not shear cleanly when the staples are driven by a staple gun. Thus, for example, it is possible that too much of this tacky filler material can be taken with a staple as it is driven, leaving the next adjacent staple to be driven in the strip with an insufficient amount of material for covering it when it is driven into the substrate. Accordingly, there is a need for a staple having filler material therein that shears evenly and cleanly when an individual staple from a strip of staples is driven into a substrate.

In accordance with another aspect of the present invention, a power tool is provided for driving fasteners, such as staples, into a substrate below a surface thereof and for covering the staples driven in the substrate with a filler material. The power tool herein provides significant savings in time and labor in that it performs both the staple driving operation and then automatically applies filler material over the driven staples with a single tool. With the power tool of the invention, directly manually rubbing or extruding the filler material into the cavity above driven staple fasteners as in the prior art and the use of different tools to perform each of these tasks is avoided. The power tool according to the present invention includes a fastener driver for driving one of the fasteners into the substrate and leaving a cavity in the substrate above the fastener driven therein, a filler material driver for driving filler material into the cavity above the fastener driven into the substrate, and an actuator for actuating the fastener driver to first drive the staple into the substrate and for actuating the filler material driver to next drive the filler material into the cavity above the driven fastener to cover it with filler material . The power tool herein thus obviates the time-consuming need to subsequently go back and cover the driven fasteners such as by rubbing filler material in the cavities or carefully aligning an extruder applicator over the cavities to squeeze filler material therein. In a preferred form, a shoe is provided on the power tool to smooth the filler material to be substantially level with the substrate surface into which the staple is driven. The shoe can include a scraper for engaging the substrate surface and being moved across the surface and over the cavity to remove excess filler material covering the staple in the substrate. In this manner, the present power tool is operable to perform staple driving, filler material driving and leveling of the filler material all in a quick and easy manner without requiring changing from one tool to the next to accomplish these different tasks.

To provide the wax-based filler material with good shearing characteristics, a shear improving amount of an additive, such as, for example, sodium bicarbonate, can be mixed with the wax-based filler material. In one form, the wax-based material and sodium bicarbonate are mixed at a predetermined ratio, such as a 1:1 ratio, to provide the filler material with good shearing characteristics .

In accordance with a preferred form of the invention, a pneumatic power tool for driving staples into the substrate surface and for driving filler material into the cavity above the staple in the substrate surface is provided and includes a staple driver actuated by pressurized air for driving the staple into the substrate surface and a filler material driver actuated by pressurized air for driving the filler material into the cavity for covering the staple in the substrate. Valve mechanisms are provided for regulating the flow of pressurized air to the staple driver and the filler material driver. A trigger actuates the valve mechanisms for operating the staple driver and the filler material driver to first drive a staple into the substrate with the staple driver and to next drive the filler material into the cavity over the driven staple with the filler material driver. The filler material driver can include a plunger and a shaft in which the plunger is mounted. An opening is provided in the shaft for receiving the extruded filler material with the filler material plunger retracted in the shaft . Operation of the trigger can cause the valve mechanism to be actuated for supplying pressurized air to cause the plunger to advance down the shaft through the opening driving the filler material out of the opening and into the cavity over the staple. The staple and filler material drivers can include respective plungers and shafts with the shafts having a common shared bottom opening so that the staples are driven by the staple driver plunger through the staple driver shaft out through the bottom opening and into the substrate therebelow and the filler material is driven by the filler material plunger out from the bottom opening to cover the staple in the substrate. As previously mentioned, the provision of the power tool with the filler material driver of the present invention obviates the need to manually apply the filler material into the cavities over the staple fasteners by rubbing or the need to load a filler material stick into an extruder applicator, carefully align the applicator with the cavities over the driven fasteners, and then manually squeeze the lever handle of the applicator to extrude the filler material into the cavities with the applicator. Instead, the present power tool is effective to automatically both drive staples into a substrate and to drive filler material into the cavities over the staples in a very easy and time efficient manner. The power tool herein is simply held over the substrate to be stapled and by operation of the trigger causes a staple to be driven into a substrate and automatically covers it with filler material which is chosen to substantially match the substrate. Thus, the staple fastener is driven into the substrate below the surface thereof and then hidden from view with a filler material in a single operation of the gun by pulling and releasing the trigger thereof without ever having to change tools or move the gun.

As previously described, the filler material can be a sticky, wax-based crayon substance. To prevent sticking of the filler material to the flat bottoms of the shafts when the filler material is driven out into the cavities over the fasteners, a low friction coating, such as a Teflon coating, can be provided on the shaft bottoms, and wherever else the filler material will touch, such as on an inner shaft. The use of the previously mentioned mixture of the wax-based filler material with sodium bicarbonate also helps limit sticking of the material to the tool surfaces. Plastic wood or other drying filler materials are also used and surfaces they contact can also be coated with a low friction coating, if needed. To make sure that the filler material is substantially flush with the substrate surface, the power tool includes a scraper shoe mounted adjacent the staple and filler drivers which includes a scraping edge for engaging the substrate surface and being moved across the surface and over the cavity to remove excess filler material covering the staple in the substrate.

The present invention also contemplates a method of driving staples into a substrate below the surface thereof and of filling a cavity formed over the staple in the substrate with a filler material and includes the steps of driving the staple into the substrate with a power tool, driving filler material into the cavity in the substrate over the staple to cover the staple with filler material with the same power tool, and leveling the filler material with the power tool so that the filler material in the cavity is substantially level with the substrate surface. As previously discussed, the present apparatus and method utilizing a single power tool for the operations of staple driving and applying filler material over the driven staples is a significant improvement in terms of time, ease of labor and cost efficiency over prior methods of accomplishing these operations.

Brief Description of the Drawings

The invention is described in greater detail in the following description of the preferred embodiment, taken in conjunction with the drawings, in which:

FIG. 1 is a front view of a U-shaped staple fastener in accordance with the invention;

FIG. 2 is a front view of a W-shaped staple fastener in accordance with the invention;

FIG. 3 is a front view of a V-shaped staple fastener in accordance with the invention; FIG. 4 is a schematic drawing of a staple gun for driving a staple fastener in accordance with the invention;

FIG. 5 is a cross-sectional view of the staple gun and staple fastener taken along the line 5-5 in FIG. 4;

FIG. 6 is a schematic view of a staple fastener and staple gun in accordance with the invention wherein the staple fastener is partially driven into a substrate; FIG. 7 is a cross-sectional view taken along the line 7-7 in FIG. 6;

FIG. 8 is a schematic view of the staple fastener and staple gun shown in FIG. 6 wherein the staple fastener is driven further into the substrate; FIG. 9 is a cross-sectional view taken along the line 9-9 in FIG. 8;

FIG. 10 is a schematic view of the staple fastener and staple gun shown in FIG. 6 wherein the staple fastener is driven completely into the substrate; FIG. 11 is a cross-sectional view taken along the line 11-11 in FIG. 10;

FIG. 12 is a cross-sectional view as shown in FIG. 11 wherein the primary plunger 44 is retracted;

FIG. 13 is a schematic view of the staple fastener and staple gun shown in FIG. 6 wherein the primary plunger is retracted and the secondary plunger is fully extended;

FIG. 14 is a cross-sectional view taken along the line 13-13 in FIG. 13; FIG. 15 is a perspective view of a staple fastener strip in accordance with the invention;

FIG. 16 is an elevational view of a power tool for driving staples and for driving a filler material over the staples according to the present invention; FIG. 17 is an enlarged end elevational view of a staple carrying filler material and supported in a staple cartridge of the power tool; FIG. 18 is a side elevational view showing a strip of staples with one staple being positioned in a staple driving shaft of the power tool staple driver with the staple driver plunger in a retracted position in the shaft over the staple therein;

FIG. 19 is an enlarged side elevational view of the open staple cartridge having a portion thereof broken away to show the cartridge staple pusher assembly and showing a strip of staples to be inserted in the cartridge;

FIG. 20 is a bottom plan view of the open staple cartridge receiving the staple strip therein; and

FIG. 21 is an enlarged side elevational view of the front of the power tool showing the staple driver shaft and a filler material driver having a plunger and shaft with the filler material plunger shown extended in its shaft with the staple driver plunger in the retracted position in its shaft;

FIG. 22 is a view similar to FIG. 21 showing the filler material plunger being retracted up into the filler material driver shaft;

FIG. 23 is a view similar to FIG. 22 showing the staple driver plunger extended through the staple driver shaft in its operative position to drive a staple fastener into a substrate with the filler material from the fastener extruded through a filler material opening in the filler material driver shaft;

FIG. 24 is a view similar to FIG. 23 showing the filler material plunger being extended down the filler material driver shaft towards the filler material therein as the staple driver plunger is being retracted up into the staple driver shaft;

FIG. 25 is a view similar to FIG. 24 showing the filler material plunger advanced fully in the filler material driver shaft in its operative position to push the filler material out from the filler material opening and into the cavity formed over the staple in the substrate;

FIG. 26 is a end elevational view of the staple in the substrate with the filler material plunger driving filler material into the cavity over the staple;

FIG. 27 is a sectional view of a valve mechanism for regulating the flow of pressurized air to and from the filler material driver;

FIG. 28 is a perspective view of a staple gun for filled staples having a horizontal air cylinder adjacent the staple cartridge;

FIG. 29 is another perspective view of the staple gun shown in FIG. 28; and

FIG. 30 is an enlarged, broken away view of a rack and gear drive in the nose of the staple gun of FIGS. 28 and 29.

Detailed Description of the Preferred Embodiment

As shown in FIG. 1, a staple fastener 10 in accordance with the invention includes two longitudinally extending leg portions 12 that are interconnected via a head or cross bar 14. Each leg portion 12 has a sharp tip 16. An extrudable filler material 18 is initially disposed between the leg portions. Typically, the staples are formed of metal, usually a metal wire, and may have various cross-sections, lengths and widths. The extrudable filler material 18 may be any suitable material for filling a cavity 61 (FIG. 14) on the surface of a substrate 60 formed when staple fastener is driven below the surface of the substrate. When the substrate is a wood material, the filler material 18 is preferably either a crayon material, wax material, wood putty material, or other material. Typically, the filler material is colored so that the cavity is filled and the colored filler is flattened to conform to the substrate surface to render the staple location more or less invisible to the casual observer. The filler material is usually in the form of moldable, putty-like material that can be shaped under pressure to a final shape to fill a cavity completely.

An alternative embodiment of a staple fastener in accordance with the invention is shown in FIG. 2. The staple fastener 20 has leg portions 22a-22d that form a W-shaped staple. Extrudable filler material 24 is disposed between the leg portions.

An alternative embodiment of the staple fastener in accordance with the invention is shown in FIG. 3. The staple fastener 26 includes leg portions 28 that are connected at their distal end to form a sharp tip 30. Extrudable filler material 32 is disposed between the leg portions . The staple fastener in accordance with the invention is driven by a staple gun mechanism, which has a primary plunger to drive the staple and a secondary plunger to tamp and smooth the filler material 18 in the cavity 61. The preferred staple gun mechanism 40 is a conventional staple gun mechanism made by one or more conventional staple or nailing gun manufacturers; and it has the usual handle, body and cartridge holder for holding the usual strip of staples. However, in the present invention, there is provided a strip 64 (FIG. 15) of staples 10, each filled with a filler material 18. The illustrated staple gun mechanism is pneumatically driven by a piston and cylinder (not shown) which are connected to a source of compressed air. It is to be understood that electrically powered staple gun mechanisms or other powered gun mechanisms may be adapted to tamp and level the filler material automatically after the staple has been first driven and the cavity 61 has been formed above the head 14 of the staple. Herein, the staple gun mechanism has been modified by adding a secondary barrel or plunger shaft 46 having an internal rectangular bore 46a in which is a secondary plunger 48 guided within the bore for reciprocating travel. The gun mechanism 40 has the conventional primary barrel or plunger shaft 42 in which a primary plunger 44 is guided for travel in a rectangular bore 42a of shaft 42. The bottom of the primary bore has an opening 40b through which the staple 10 and lower end 48a of the secondary plunger 48 are sequentially discharged. The primary plunger 44 is disposed within the primary plunger shaft 42 for vertical movement. The primary plunger 44 is part of the drive mechanism for driving staple fasteners into a substrate. As further described below and shown in

FIGS. 5-13, the primary plunger shaft 42 houses a filled staple fastener which is driven by the primary plunger 44.

As shown in FIG. 4, the staple gun 40 has the secondary plunger shaft 46 oriented at an angle A relative to the vertically-oriented primary plunger shaft 42. A secondary plunger 48 is disposed for longitudinal movement within the secondary plunger shaft 46. As discussed below and shown in FIG. 13, the secondary plunger 48 moves downwardly to drive the filler material 18 into the cavity 61 and tamp the filler into cavity to fill the cavity completely and to level the top surface of the filler material level with the top surface of the substrate . As shown in FIG. 4, the secondary plunger 48 is spring loaded with a spring 62 which retracts and maintains the secondary plunger 48 in the retracted position. A piston 50 is connected to the upper end of the secondary plunger 48. When the air pressure in the upper end 51 of the secondary plunger shaft 46 is increased, the piston 50 is depressed, thus driving the secondary plunger 48 downwardly, against the bias of spring 62. Preferably and as shown in this preferred embodiment, the increase in air pressure comes from the exhaust gas from the primary plunger shaft 42 within the gun mechanism 40. The illustrated gun mechanism of has been modified to give the timing of the operation of the secondary plunger 48 such that the primary plunger 44 has been retracted from the cavity 61 and lifted above the packer opening 54, which opens into the primary bore 42a, preferably just above the discharge opening 40b of the primary bore 42a. The extruded filler material 18 is confined from spreading laterally by the primary plunger shaft 42 which is being pressed tightly against the substrate. A lower end 48a of the secondary plunger 48 is formed at a bias angle to the longitudinal axis of the secondary plunger shaft so as to be horizontal, as is the horizontal surface of the substrate. Stated differently, the end 48a of the stamping plunger 48 is in a plane perpendicular to the longitudinal axis of the primary shaft 42. When the end 48a is tamping the filler material 18, it will extend into the discharge opening 40b of the primary shaft 42, and will have forced any extruded filler material down out of the secondary bore 46a into the cavity and then tamps it firmly. The amount of filler material is chosen so that it fills the cavity 61 when tamped under pressure by the end 48a of the secondary plunger shaft.

Referring to FIG. 4, at the bottom of the staple gun 40, the opening 40b is a shared opening, which serves as the opening for both the primary plunger shaft 42 and the secondary plunger shaft 46. The shared shaft opening 40b communicates with a packer opening 54 for the secondary plunger shaft 46. As best seen in FIGS. 4 and 5, the rectangular wall of the primary shaft 42 facing the secondary shaft 46 has its lower end cut away to leave the rectangularly-shaped opening 54 for the secondary plunger shaft 46 to move into the bottom of the primary shaft bore 42a, as shown in FIG. 13. The packer opening 54 has a height dimension to pass the lower tip of the secondary plunger shaft 46, and this height is shown by the arrows "b" in FIG. 5. The packer opening 54 receives filler material as it is extruded from the staple fastener 10, as described below and shown in FIGS. 8 and 10.

Referring to FIG. 5, the staple fastener 10, with filler material 18 disposed between the leg portions 12, is slidably disposed within the primary plunger shaft 42.

FIGS. 6 and 7 show the primary plunger 44 in the middle of its downward stroke whereby the staple fastener 10 is partially driven into the substrate 60. As the primary plunger 44 moves downwardly within the primary plunger shaft 42, it contacts the top of the staple fastener 10, and thereby drives the staple fastener 10 downwardly into the substrate 60. During the downward stroke of the primary plunger 44, the secondary plunger 48 remains stationary in its rest position within the secondary plunger shaft 46.

As shown in FIG. 7, the inverted U-shaped staple fastener 10 initially pierces the substrate 60 with the sharp tips 16 of the leg portions 12. Initially, the filler material 18 is undisturbed.

Referring to FIGS. 8 and 9, the primary plunger 42 is shown after it has descended further in its downward stroke, and has driven the staple fastener 10 further into the substrate 60. The secondary plunger 48 is still in its rest position stationary within the material 18 to secondary plunger shaft 46. As shown in FIG. 9, the filler material 18 is contacted by substrate 60, and is extruded from between the leg portions 12 of the staple fastener 10 and upwardly into the packer opening 54 of the secondary plunger shaft 46.

When the primary plunger 44 reaches the bottom of the downward stroke within the primary plunger shaft 42 (FIGS. 10 and 11) , the staple fastener 10 is driven completely into the substrate 60. The bottom portion of the primary plunger 44 is slightly below the level of the surface of substrate 60. The secondary plunger 48 remains stationary within the secondary plunger shaft 46. Most of the filler material 18 is extruded from the staple fastener 10 into the opening of the secondary shaft 46. After completing its downward stroke, the primary plunger 44 retracts, and, as shown in FIG. 12, a cavity 61 on the surface of substrate 60, above the staple fastener 10, is formed. The lower end of the primary plunger has been filling the cavity 61; and as this lower end retracts, the cavity is available to be filled by the filler material.

After the primary plunger retracts above opening 54 in the secondary plunger shaft 46, the secondary plunger 48 is driven downwardly by exhaust gas pressure to be fully extended to the bottom of its downward stroke, as best seen in FIGS. 13 and 14. The secondary plunger 48 pushes and tamps the filler material 18 in the cavity 61. The bottom end 48a of secondary plunger 48 preferably extends across the cavity 61 so as to conform the filler material 18 have an outer surface 63 to flush with the surface of substrate 60 rendering the staple fastener location invisible.

After the secondary plunger shaft 48 completes the tamping step, it is retracted within the secondary plunger shaft 46 such as by a coiled spring 62 (FIG. 13) , and the staple gun may be removed.

When using the staple 26 shown in FIG. 3, the primary plunger 44 will hit the top ends of the staple legs 28, which are vertical and parallel at their upper ends. Preferably, the straight leg 28 has a sharp pointed end which will be perpendicular to the substrate when the straight leg is impacted by a blow from the primary plunger. Because the curved leg has a lower curved portion 28a of concave shape, the wood of the substrate will squeeze this curved portion toward the straight leg forcing the filler material 32 to be displaced upwardly into the top half of the staple. As the primary shaft 44 is driven into the substrate to create the cavity 61 (FIGS. 10-12), the filler material between the staple legs 28 is extruded through the opening 54 leading into the secondary shaft 46, as best seen in FIG. 12. Then, as best seen in FIG. 13, the secondary shaft 48 is operated to displace the extruded material back through the opening 54 and into the now- empty countersink cavity 61 to leave the top surface 63 of the filler material flush with outer substrate surface 60. The W-shaped staple operates in a similar manner, as the straight legs 22a and 22d are driven straight into the substrate 60 and are disposed perpendicular to the substrate. The inner legs 22b and 22c are angled to the vertical; and the substrate wood will force these legs 22b and 22c to move toward their adjacent, associated, straight legs 22a and 22d, respectively and squeeze the filler material 24 upward as the staple 20 is driven into the substrate. Eventually, the primary shaft 44 will countersink the upper ends of the legs 22a-22d, leaving a cavity 60 to be filled with the extruded filler 24 that will have passed through opening 54 into the bottom of the bore 46 (FIG. 12) . Then, when the secondary plunger 48 is operated, the filler material is pushed into and tamped into the cavity 61, leaving a surface 63 flush with the substrate surface 60.

A strip 64 of staple fasteners 10 made in accordance with the invention is illustrated in FIG. 15. The staple fasteners 10 are arranged in a front-to-back relationship with adjacent fasteners 10 adhered to one another in a conventional manner used to secure together nails or the like, such as by strips 120 of a coating applied to the adjacent legs of the staples. Filler material 18 fills the strip 64. If the filler material 18 is a wood putty, or other material that dries when exposed to air, then the filler material, after it has been applied to the staple fastener strip 64, is preferably coated with an airtight sealant to prevent drying of the filler material while the strip 64 remains intact. After the staple strip 64 is placed into a staple gun and staple fasteners 10 are sheared from the strip 64 one at a time during use of the stapling gun, then, for each removed staple fastener 10, most of the filler material 18 is not covered by the sealant. The small amount of sealant on the filler material 18 in the staple fastener will not interfere with subsequent drying of the filler material. While FIG. 15 shows a strip of U-shaped staple fasteners, the strip may be formed with staple fasteners having a variety of shapes, including those shapes disclosed above.

Another embodiment of the invention is shown and described hereinafter in connection with FIGS. 16-27.

Referring now to FIG. 16, there is illustrated, a power tool apparatus 210 for driving staple fasteners 212 into a substrate 214 and for then filling the recess or cavity 216 formed over the staple fastener 212 with a filler material 218 is illustrated. In FIG. 16, the power tool apparatus 210 of the present invention is depicted in the form of a modified, commercially available pneumatic staple gun in which pressurized air is utilized to actuate a staple driver 220 and a filler material driver 222. One such gun that can be readily modified with the filler material driver 222 in accordance with the present invention is provided by Stanley-Bostitch^® in East Greenwich, Rhode Island. Pressurized air from a source, such as an air compressor (not shown) , is provided to the pneumatic gun 210 by way of an air hook-up fitting 224 provided at the rear of the tool 210. The power tool also may be an electric motor driven tool rather than a pneumatic tool. The illustrated fastener is called a staple; but other shapes and kinds of fasteners may be used other than the traditional two-legged, inverted U- shaped staple and fall within the purview of the invention. The tool 210 is also provided with a lower staple cartridge housing 226 in which a strip 228 of staples 212 can be loaded. The staple cartridge 226 feeds staples 212 from the strip 228 one staple at a time to the staple driver 220 for being driven into the substrate 214.

In the preferred and illustrated form, the staples 212 carry the filler material 218 between their elongate tangs or legs 212a and 212b at the closed end of the staple 212 having head 213 interconnecting the legs 212a and 212b, as best seen in FIG. 17. The power gun 210 can be adapted to drive staples 212 having legs 212a and 212b sized approximately at 1-1/8 inches in length and a head 213 extending approximately 1/4 of an inch between the staple legs. Manifestly, the gun 210 herein can be adapted to drive a wide variety of differently sized fasteners. After the staple fastener 212 is driven by the staple driver 220 into the substrate 214 (FIG. 23) , the filler material 218 extruded from the driven staple fastener 212 is driven by the filler material driver 222 of the gun 210 into the cavity 216 to cover the staple fastener 212 to conceal the driven staple 212 from view (FIGS. 24-26) . Accordingly, the present power tool apparatus 210 is effective to automatically perform both the staple driving operation and the operation of covering the driven staple with filler material with the single power tool apparatus 210 herein which provides significant labor and time savings over the previous methods of having to go back and individually cover the driven staples by manually rubbing the filler material into the cavities or by using an extruder applicator to direct the filler material into the cavities.

The description in this application is to the preferred embodiment wherein the substrate is wood, the fasteners are staples, and the filler material is colored to match the color of the wood substrate. The fasteners may be other than the described staples, and the fasteners may be driven into other substrates, such as materials, in addition to wood, that are primarily designed for exterior, outdoor applications, like roofing shingles, with the filler material being a caulk, silicone adhesive or the like to fill and cover the recess above the fastener. Thus, if the fasteners are used in installing an outdoor wood deck or a new roof, or in other outdoor applications where the fasteners, if not covered, would be exposed to the environment, such filler material can prevent leaks from developing, and protect the fastener from ambient weather, such as rain, snow, ice, etc. and, if the fastener is of a metallic material, such filler will protect it against potential rusting. Manifestly, there are other uses than those uses described herein which uses are described by illustration and not by limitation; and these other non-described uses will fall within the purview of the appended claims.

Another feature of the present invention is the provision of a scraper shoe 230 at the bottom of the power tool apparatus 210 adjacent the drivers 220 and 222, as seen in FIG. 16. After the filler material driver 222 has driven filler material 218 into the cavities 216, the power tool 210 can be moved to draw the scraper shoe 230 across the cavity 216 for scraping away excess filler material 218 to level the filler material 218 in the cavity 216 with the substrate surface 214a. Thus, use of the power tool apparatus 210 allows an operator to apply staple fasteners 212 into a substrate 214, cover staple fasteners with filler material 218, and scrape excess filler material 218 away from the substrate surface 214a with the scraper shoe 230 all with the one power tool 210 without having to change tools. This provides a quick and easy apparatus and method for accom¬ plishing power what previously required separate procedures utilizing a power gun for driving the staple fasteners and the operation of non-powered tools such as an extruder applicator and a separate scraping blade for respectively applying filler material into the cavities over the fasteners and scraping the excess filler material from the substrate surface to be level therewith.

The illustrated form of the power tool apparatus 210 will next be more particularly described. As previously mentioned, the power tool apparatus or gun 210 is preferably adapted to hold a strip 228 of staples 212 by way of cartridge housing 226. Referring to FIGS. 17- 20, the cartridge housing 226 includes an upper staple guide portion 232 and a lower staple support portion 234. The cartridge lower portion 234 can be slid out from the cartridge upper portion 232, as shown in FIGS. 19 and 20, by pivoting latch member 236 upwardly in a clockwise direction. Pivoting the latch member 236 pivots the abutment surface 238 thereof so as to allow transverse pin 240 provided at the rear of the cartridge lower portion 234 to be moved rearwardly past the latch member 236 for sliding of the cartridge lower portion 234 out from the cartridge upper portion 232. The latch member 236 is normally biased in a counter-clockwise direction to its locking position, as shown in FIGS. 16 and 19, so that when the cartridge lower portion 234 is slid out from the cartridge upper portion 232 and the latch member 236 is released, the latch member 236 will move counter- clockwise back to the normal locking position. With the cartridge 226 open by sliding of the lower portion 234 out from the upper portion 232, the staple strip 228 can be loaded into the interior 242 of the cartridge upper staple guide portion 232, with the head 213 of the staples 212 against the interior side of the top wall 244 of the cartridge upper portion 232 and with the legs 212a and 212b tightly received between the sidewalls 246 and 248 depending from the cartridge upper portion top wall 244 for sliding movement therealong, as best seen in FIGS. 17 and 18.

Closing the cartridge housing 226 causes the staple strip 228 to be pushed forwardly therein so that the forwardmost staple 212 ' at the front end of the strip 228 is positioned in the staple driver 220. More specifically, the staple driver 220 includes a primary or staple driver shaft 250 in which a primary or staple driver plunger 252 is mounted for sliding reciprocating movement. The staple driver shaft 250 can have bore 250a which is preferably of a substantially rectangular cross- sectional configuration so as to fit an individual staple fastener 212 for sliding movement therein as it is driven by the staple driver plunger 252. The staple driver shaft 250 is formed by fixed nosepiece 254 rigidly attached to the front of the gun 210 and the front surface 256 of the cartridge lower support portion 234 when the cartridge housing 226 is closed. Once the staple strip 228 is inserted into the cartridge upper staple guide portion 232 as previously described, the cartridge lower staple support portion 234 can be slid fully back and locked into the upper staple guide portion 232 with the front surface 256 in tight fitting relation with the nosepiece rear surface 258 to form the staple driver shaft 250.

To slide the cartridge lower support portion 234 to the closed position, the pin 240 of the cartridge lower portion 234 is pushed against a cam surface 259 of the latch 236. The cartridge lower portion 234 is constrained against downward movement by the engagement of its lip flange 260 with interior rails 246a and 248a (FIG. 20) formed at the bottom of respective sidewalls 246 and 248 of the cartridge upper portion 232. Thus, as the cartridge lower portion 234 is slid into the cartridge upper guide portion 232 with the lip flange 260 sliding on the rails 246a and 248a, engagement of the pin 240 with the cam surface 259 will cause the cam surface to ride up on the pin 240 with the latch member 236 pivoting upwardly in a clockwise direction against its counter-clockwise bias until the pin 240 clears the lowestmost point 259a of the cam surface. The latch member 236 can then snap back into place as a result of its counter-clockwise bias for capturing the cartridge lower portion 234 in closed position in the cartridge upper portion 232 with the latch abutment surface 238 abutting the rear of the pin 240.

The cartridge lower portion 234 further includes a staple pusher assembly, generally designated 262, which is spring loaded as by spring 264 to urge the staple strip 228 forwardly in the interior 242 of the cartridge upper portion 232. More specifically, the cartridge lower portion 234 includes a rear grip 266 to which the transverse pin 240 can be attached, a lower sliding section 270 including the lip flanges 260 thereon, a staple support bar 272, and a forward shaft-forming section 274 interconnecting the forward ends of the support bar 272 and the lower slide 270. An elongate spring mounting rod 276 extends in a window 278 formed between the lower slide 270, the upper support 272, the rear grip 266 and the front shaft forming section 274. The spring mounting rod 276 is attached at its rear end to the front of the rear grip 266 and can extend forwardly in the window 278 to the shaft forming section 274. The spring 264 is coiled about the rod 276 with its rear coil abutting the back surface 278a of the window 278. A pusher block 280 is slidingly mounted on the rod 276 and engages the front coil of the spring 264 so that the pusher block 280 is biased forwardly on the rod 276 in the window 278 by the spring 264. Manifestly, the bias force on the pusher block 286 can be controlled such as by providing a second spring and a rod about which the second spring is coiled and on which the pusher block 280 is slidingly mounted in a manner similar to the above- described spring 264 and rod 276 arrangement.

Thus, when the staple strip 228 is loaded in the interior 242 of the cartridge upper portion 232, sliding the cartridge lower portion 234 into the upper portion 232 will cause it to initially encounter the rear of the staple strip 228. A staple engaging member 282 is provided and configured so as to be engaged by the pusher block 280 with the pusher block 280 pushing the staple engaging member 282 forwardly for sliding along the support bar 272. A portion 272a of the front of the support bar 272 is exposed forwardly of the staple engaging member 282 for receiving the staples 12 at the rear of the staple strip 228 as the cartridge lower portion 234 is slid into the cartridge upper portion 232 before engaging the rear of the staple strip 228 with the staple engaging member 282. The support bar 272 can be provided with a cut-out section as at 284 to provide it with a lower profile, as seen in FIG. 19. In this manner, as the cartridge lower portion 234 is slid forwardly in the interior 244 of the cartridge upper portion 232, the support bar 272, which is sized with a width narrow enough to fit between the staple legs 212a and 212b of the staples 212 in the staple strip 228, will slide therebetween with the lower profile bar 272 accommodating the added filler material 218 carried between the legs in the staples so that the bar 272 is closely adjacent the filler material 218, as best seen in FIG. 17. Thus, the staple support bar 272 is effective to support the staple fasteners 212 with the top of the staple support bar 272 against the bottom of the filler material 218 carried by the staples 212.

As the cartridge lower portion 234 is slid further into the cartridge upper portion 232, the member 282 will engage the rearmost staple 212 ' in the strip 228. Continued sliding of the cartridge lower portion 234 causes the forwardmost staple 212' to be pushed into channel 286 formed in the nosepiece rear surface 258. With the staple 212' engaged in the channel 286, continued sliding of the cartridge lower portion 234 into the upper portion 232 causes the block 280 and member 282 to be pushed against the bias of the spring 262 compressing the spring 264 and thereby spring loading the staples 212 forwardly in the cartridge upper portion interior 242, with the forwardmost staple 212' being urged into the channel 286. With the cartridge lower portion 234 locked into the cartridge upper portion, the staple support bar 272 will be in supporting position underneath each of the staples 212 in the strip 228 except for the forwardmost staple 212' which is in position to be driven by plunger 252 through bore 250a. Closing the cartridge 226 brings the shaft forming section 274 of the cartridge lower portion 234 against the nosepiece 254 to form the staple driver shaft 250 with the front surface 256 of the cartridge lower portion 234 and the channel 286 formed in the nosepiece rear surface 258 cooperating to define the bore 250a through which the forwardmost staple 212' in the strip 228 is driven.

Once the staple driver 220 is actuated, as will be more fully described hereinafter, the staple driver plunger 252 advances down the shaft 250 with sufficient force to break off the staple 212 ' from the remaining staples 212 in the staple strip 228. When the staple 212 ' is broken off from the remainder of the staples in the strip 228, the filler material 218 associated therewith also has to shear from the remainder of the filler material in the staples left in the strip 228. The staples 212 are each filled with a predetermined amount of filler material 218 with the predetermined amount being an amount sufficient to fill the cavity 216 above the staples 212 driven into substrate 214. Thus, it is desirable that the staple 212' only take the predetermined amount of filler material associated there¬ with when it is broken off from the staple strip 228 by the plunger 252. However, with presently available wax- based, crayon-type filler material, such as the filler material provided by Star Finishing Products of Hinsdale, Illinois, the filler material 218 may lack the shearing qualities necessary for it to break cleanly from the filler material in the next adjacent staple 212 in the strip 228. If the filler material 218 is too hard and does not break cleanly, it is possible that too much filler material 218 will be taken with the staple 212' being driven through the shaft 250 so that the next adjacent staple 212 does not carry a sufficient amount of filler material to cover the cavity 216 formed thereover when it is driven by the plunger 252. On the other hand, it is also possible that when the staple 212 ' is broken from the strip 228 that an insufficient amount of filler material 218 will be broken off therewith leaving excess filler material in the next adjacent staple so that when the staple 212' is driven into the substrate 214, an insufficient amount of filler material 218 will be present to cover the driven staple 212' . Ideally, the filler material 218 in a given staple 212 would be sheared evenly and cleanly in the plane between two adjacent staples.

To improve shearing of the wax-based filler material, the wax material can be melted and mixed with an amount of shear improving agent in a predetermined ratio therewith so that the filler material shears cleanly with each stroke of the staple driver. For example, one such mixture which can be used includes sodium bicarbonate as a shearing agent in preferably a 1:1 ratio with the filler material. The mixture with sodium bicarbonate has been found to improve the shearing qualities of the filler material 218 so as to limit the problems described above. Manifestly, many other types of filler materials and/or shearing additives may be utilized to achieve the desired shearing qualities. Another filler which can be used with the staple strip 228 is a so-called plastic wood material which is readily sandable after it has been applied into the cavities over the fasteners and has dried. To apply the plastic wood filler material 218 in the staples 212 of the strip 228, the material is coated with paraffin wax to provide an airtight seal around the exposed surfaces of the material so that it will not oxidize and dry until it is exposed by being sheared and then driven into the cavities 216 over the driven fasteners 212 by the power tool 210 herein.

As previously described, as staples 212 are driven into substrate 214, the filler material 218 carried thereby extrudes out from the between the legs 212a and 212b of the staples 212. The present power tool gun apparatus 210 is operable to apply this extruded out filler material 218 back into the cavities 216 formed above the driven staple fasteners 212. To accomplish this, the filler material driver 222 is provided which operates similar to the staple driver 220. The filler material driver 222 includes a secondary or filler material driver shaft 288 formed in the nosepiece 250 in which a secondary or filler material driver plunger 290 can be reciprocated. The axis 289 of shaft bore 288a is angled relative to the axis 259 of shaft bore 250a by angle A, as shown in FIG. 18. The nosepiece triangular portion 224a has a plunger opening 294 formed in its upper surface 296 with the plunger opening 294 being spaced forwardly from the staple driver shaft bore 250a. The channel or bore forward surface 298 stops short of the bottom of the nosepiece 254 to provide a filler material opening 100 thereat. The opening 300 is sized such that the plunger 290 extending through the plunger opening 294 can slide through the filler material opening 300 during its downward stroke into the bottom of the driver shaft 250a. In addition, the filler material opening 300 provides the filler material 218 with a pathway as it is extruded from a driven staple 212 by the staple driver plunger 252, as shown in FIG. 23.

The nosepiece 254 includes a flat bottom surface 302 having a substantially rectangular bottom opening 302a formed therein which serves as a common or shared bottom opening for both the staple driver plunger 352 and the filler material driver plunger 290 when they are advanced through their respective shafts 250 and 288 in their downward or driving strokes. Thus, when the staple driver plunger 252 is fully extended through its shaft 250 for driving a staple fastener 212 into substrate 214 therebelow, the filler material 218 carried by the driven staple 212 extrudes up around the staple head 213 and the end of the staple driver plunger 252, and through the bottom opening 302a while being confined from spreading laterally by the nosepiece bottom surface 302 which is being pressed firmly flush against the substrate surface 214a. The access of the extruded filler material 218 to the shaft bore 250a of the staple driver 220 is substantially blocked by the extended plunger 252 therein (FIG. 23) so that the filler material 218 will instead continue to flow upward in the path of least resistance into the unblocked bore 288a of the filler material driver shaft 288 through the filler material opening 300 thereof. There the filler material 218 is ready to be driven back into the cavity 216 formed over the driven staple 212 by the filler material driver plunger 290, as described more fully hereinafter.

The preferred power tool gun 210 is pneumatically operated and, accordingly, both the staple driver 220 and the filler material driver 222 are actuated by pressurized air. The filler material driver 222 can include a pneumatic cylinder 304 in which a piston 306 is reciprocated in response to pressurized air provided into the cylinder 304. The piston 306 has the filler material driver plunger 290 attached thereto and which extends exteriorly of the cylinder 304 and into the plunger opening 296 of the nosepiece 254. The cylinder 304 is mounted to the front of the tool by bracket 308 so that the axis 305 of the cylinder 304 coincides with the axis 289 of the shaft 288 so that the plunger 290 is properly aligned for reciprocating movement in the shaft 288. Manifestly, it will be appreciated that other re¬ locations for the filler material driver 222 may be utilized, such as in side-by-side relation with the staple driver 220.

With the pneumatic tool 210, both the staple driver 220 and filler material driver 222 include valve mechanisms for regulating pressurized airflow thereto. The valving mechanism 308 for the filler material driver 222 is shown in FIGS. 16 and 27. The valving mechanism for the staple driver 220 can be that provided in the commercially-available Stanley-Bostitch^® staple gun, and thus is not described in detail herein. Both the staple driver and filler material driver valving mechanisms are controlled by operation of an actuator, such as the illustrated trigger operator 310. In some instances, the actuator for causing the operation of the power tool may be a contact that is pressed against the substrate to actuate the tool . The actuator for the power tool may take various forms. Depressing and releasing the trigger 310 causes respective exterior stems of the valve members to move for controlling airflow through the respective valving mechanisms.

For providing the filler material driver 222 with pressurized air, the cylinder 304 is provided with ports 312 and 314 to which air lines 316 and 318, respectively, are connected. A supply line 320 is split off at an elbow 224a of the fitting 224 to supply pressurized air from the compressed air source to the valving mechanism 308.

The valving mechanism 308 includes an exterior stem 322 which is connected to valve member 324 with the stem 322 and valve member 324 being spring biased by spring 326 in the valving mechanism body 308a so that the stem 322 projects exteriorly of the body 308a for being depressed by pulling on the trigger 310. Similarly, the stem 326 for the staple driver valving mechanism (not shown) is also biased exteriorly from its associated valve mechanism body to be depressed by the trigger 310. The following is a detailed description of the operation of the valving mechanism 308 although it will be recognized by those skilled in the art that many other forms of valves could be utilized to regulate pressurized air for reciprocating the plungers 252 and 290 for their respective driving functions as described herein. In addition, although the filler material driver 222 and valving mechanism 308 therefor are shown mounted exteriorly to the known staple gun with the filler material driver 222 mounted to the front end of the staple gun and the valving mechanism 308 mounted in a gripping opening 328 of the tool body 210a defined by tool rear vertical portion 330 and tool forward vertical portion 332 on either end of the gun 210 and gripping handle 334 and staple cartridge 226 at the top and bottom of the gun 210, it will also be recognized that the gun 210 can be modified to accommodate the filler material driver 222 and its associated valving mechanism 308 and air lines 316-320 at other locations around the tool body 210a and in the interior of the tool body 210a. In the illustrated form, the trigger 310 is normally biased to its down position where both stems 322 and 326 are fully extended. The trigger 310 can also be modified to include an extension 336 formed of a spring steel material which is oriented so that when the trigger 310 is pulled upwardly, the extension 336 will cause the stem 322 to be pushed in towards the valve body 308a thus compressing the spring 326 to move the valve member 324 longitudinally therein. Turning to FIGS. 21-26, operation of the power tool 210 will next be described. Initially, the tool 210 is oriented over the substrate 214 at the location into which the staple fastener 212 is to be driven. The scraper shoe 230 is provided with a lower or bottom scraping edge 230a which is substantially aligned with the bottom surface 302 of the nosepiece 254. The nosepiece 254 is brought into engagement with the substrate surface 214a so that the nosepiece bottom surface 302 is substantially flush with the substrate surface 214a. In this manner, the axis 251 of the staple driver shaft 250 is oriented substantially perpendicular to the substrate surface 214a for proper driving of the staple 212 into the substrate 214. The scraping edge 230a can be used to ensure that the nosepiece bottom surface 302 is flush with the surface 214a by providing the user a pivot point for use in establishing the flush position. First, the user engages the scraper edge 230a with the substrate surface 214a and then pivots the tool 210 to bring it down onto the substrate surface 214a until the nosepiece bottom surface 302 is engaged therewith while keeping the scraper edge 230a in contact with the surface 214a. Thus, the scraper shoe 230 helps in finding the flat and getting the nosepiece 254 planar and flush with the surface 214a. In addition, when firing the gun 210, the shoe 230 helps keep the nosepiece bottom 302 flush against the flat surface 214a to stabilize the tool 210 during its driving operations. With the source of compressed air attached to fitting 224 and turned on and the trigger operator 310 in its down position as shown in FIG. 16, the staple driver plunger 252 will be retracted in its shaft 250 in the inoperative position so that it is above staple 212' which is positioned in the shaft 250 to be driven. Before the staple 212' is driven, the valve 308 regulates airflow therethrough so that pressurized air is supplied through the air line 316 and into the top of the pneumatic cylinder 304 by way of air port 312. For this flow of air through the valve body 308a, the valve mechanism 308 is as depicted in FIG. 27 wherein the stem 322 is biased by spring 326 and projects fully out from the valve body 308a. In this position of the valve member 324, end seal 324a and intermediate seal 324b thereon are effective to allow incoming air from supply line 320 to only communicate with port 316a to which air line 316 is connected. The end seal 324a seals exhaust port 340 and intermediate seal 324b seals port 318a from the supply air. With pressurized air being supplied to the top of the cylinder 304 by line 316, the piston 306 and attached filler material plunger 290 are extended downwardly out from the pneumatic cylinder 304 with the plunger 290 fully extended in its shaft 288, as shown in FIG. 21. Air in the bottom of the cylinder 304 is pushed out through port 314 into line 318 and through port 318a into valve body 308a. The intermediate seal 324b and end seal 324c are effective to allow exhaust air from cylinder 304 coming into the valve mechanism 108 from line 318 to communicate with exhaust port 338 and thus exit from the valve body 308 to atmosphere through port 338.

With the tool 210 in proper position on the sub¬ strate 214a, the user pulls on the trigger operator 310 which causes the extension 336 attached thereto to initially depress the stem 322 in towards the valve body 308 with the valve member 324 moving longitudinally therein against the bias of the spring 326. When the stem 322 is depressed sufficiently and the valve member 324 is moved longitudinally against the spring 326 in the valve body 308a, the airflow entering the body 308a from supply line 320 will no longer be in communication with the port 316a, and instead will be in communication with the port 318a by way of the longitudinal movement of the associated seals 324b and 212c of valve member 324. Thus, with the trigger operator 310 pulled up sufficiently so as to depress the stem 322 and before the stem 326 has been depressed, the pressurized air will flow out form port 318a through line 318 into the bottom of the pneumatic cylinder 304 by way of air port 314 causing the piston 306 to move upwardly within the cylinder 304 retracting the plunger 290 up and away from the shared bottom opening 302a through the filler material opening 300 retracted in the shaft 288 in its inoperative position, as shown in FIG. 22. The longitudinal movement of the valve member 324 also moves the associated seal 324c sufficiently so that it seals off the exhaust port 338 so that it no longer is in communication with the port 318a. At the same time, the end seal 324a is moved sufficiently so that it no longer seals open exhaust port 340 from port 316a. Thus, air forced out of the top of cylinder 304 through cylinder port 312 into line 316 by the retracting movement of the plunger 290 and piston 306 in the cylinder 304 will flow through line 316 through port 316a into valve body 308a and will exit from the valve body 308a to atmosphere through open exhaust 340.

Continued upward pulling on the trigger next causes the stem 326 to be depressed with the extension 336 keeping the stem 322 depressed so that the plunger 290 is maintained in its retracted inoperative position while the staple driver valving mechanism regulates airflow to direct air pressure so as to advance the staple driver plunger 252 in the downward direction in its shaft 250. As plunger 252 moves down the shaft 250, it engages the head 213 of staple 212' positioned in the shaft 250 to push it down the shaft bore 250a and out through the bottom opening 302a into the substrate 214 therebelow, as shown in FIG. 23. As the staple 212' is driven into the substrate, the filler material 218 carried thereby will extrude out from between the legs 212a and 212b up around the staple head 213 and end of the driver 252, through the bottom opening 302a and up into the shaft 288 through the filler material opening 300. As previously mentioned, the driving of the staple 212' into the substrate 214 leaves a cavity 216 formed in the substrate surface 214a above the staple base 213.

Once the staple is driven, the trigger operator 310 is released so that first, the stem 326 will return to its extended position so as to regulate airflow through the staple driver valving mechanism so that it is redirected to cause the staple driver plunger 252 to start to be retracted back from its operative driving position of FIG. 23 where its driving the staple 212', towards its inoperative position as shown in FIG. 24. At the same time as the staple driver plunger 252 is being retracted up into its shaft 250 and away from the bottom opening 302a, the continued downward movement of the trigger 310 as it is released causes the trigger extension 336 to be moved away from the stem 322 allowing it to move back to its extended position. With the stem 322 extended and the valve member 324 biased by spring 326, the airflow through the valving mechanism 308 will be as previously described with the trigger operator 310 in its down position. This causes pressurized air to flow through the line 316 into the top of the cylinder 304, in turn, causing the filler material driver plunger 290 to be advanced back down its shaft 288 towards the filler material 218 therein (FIG. 24) , until its end 290a engages the filler material 218 pushing the filler material through the filler material opening 300 and out from the bottom opening 302a into the cavity 216 over the staple 212', as shown in FIGS. 25 and 26.

The lower end 290a of the filler material plunger 290 is formed so that it is in a plane perpendicular to the longitudinal axis 251 of the staple driver shaft 250 and in a plane substantially parallel to the nosepiece bottom surface 302. Thus, as can be seen in FIGS. 25 and 26, the filler material driver plunger 290 is advanced through its shaft 288 until the plunger lower end 290a is aligned with the nosepiece bottom surface 302 and thus the substrate surface 214a for leveling the filler material 218 in the cavity 216. The nosepiece bottom surface 302 can be coated with a low friction material, such as PTFE, to limit sticking of the filler material 218 thereto. The previously described mixture of filler material 218 having improved shearing qualities, such as the wax and sodium bicarbonate mixture, also helps limit the sticking of the filler material 218 to surfaces on the gun 210.

In addition, for removing any excess filler material 218 from the substrate surface 214a, the scraper shoe 230 is mounted adjacent the shafts 250 and 288, and more specifically, mounted to the front inclined surface 342 of the nosepiece triangular portion 254a extending between the nosepiece upper surface 296 and bottom surface 302. The shoe 230 including scraping edge 230a thereof can be formed of a low-friction material such as PTFE similar to the coating provided on the nosepiece bottom surface 102 so that it can be smoothly drawn across the substrate surface 214a and over the cavity 216 to remove excess filler material projecting from the cavity 216 over the surface 214a. In this manner, the filler material 218 is compacted tightly in the cavity 216 with the top of the filler material 218 being substantially flush with the substrate surface 214a so as to conceal the driven staple 212' from view. With the plunger 290 fully extended in its operative filler material driving position, the process of driving staples and filling cavities formed thereover can be repeated as the staple driver plunger 252 is now retracted to its inoperative position over the next adja- cent staple 212 in the strip 228 as fed by the spring- loaded staple pusher assembly 262 into the staple driver shaft 250. As is evident from the foregoing, the present tool 210 provides a substantial labor savings in that a single tool is utilized to perform the tasks which previously required several distinct operations and/or different tools to perform. Use of the present power tool 210 provides increased efficiency and lower costs in the performance of stapling projects.

Another embodiment of the power tool apparatus 210a is shown in FIGS. 28-30 wherein the pneumatic gun has a cartridge housing 226a for holding a strip 228 of staples 212. The cylinder 304a is placed in a horizontal position adjacent the staples; and it has a piston rod 350 that drives a gear mechanism 352 to shift a filler material drive plunger 290. The drive plunger has a lower end 290a which engages the filler material 218 through the material filler opening 300, and which drives the filler material out from the bottom cavity opening 302a into the cavity 116 over the staple 212' .

The cylinder 304a is driven in the manner herein before described using the air control valve 308. The piston rod 350 has a rack 356 on one end in engagement with a small gear 358 fixed to a horizontal shaft mounted for rotation in the gun housing. The shaft extends horizontally and carries another gear 360 that is meshed with a curved rack 362 on the upper end of the material driver plunger 290. This plunger is guided for reciprocation in a guide track 366 in the nose of the gun.

The operation of the staple gun, shown in FIGS. 28-30, is the same as that above-described except that the rack 356, the gear mechanism and the curved rack 362 are used to convert the horizontal movement of the piston rod 350 into an inclined, downward travel for the material driver plunger 290 which functions like the material driver plunger 190 in the previously-described embodiment of the invention.

The advantage of the staple gun of FIGS. 28-30 is that it does not have the cylinder 304 on the nose of the gun, which may prevent the use of the gun in a tight corner. Thus, the gun of FIGS. 28-30 may be used in tight areas much in the manner the gun is used without the staple filler addition thereto. Also, the balance or feel of the gun is not changed because of the weight of the cylinder 304 is projecting beyond the nose of the gun. While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.

Claims

What Is Claimed Is:

1. A staple fastener comprising: at least two longitudinally extending leg portions, said leg portions being interconnected at one end thereof, said leg portions being separated and defining a space therebetween; an extrudable filler material located in and at least partially filling said space between said leg portions.

2. A staple fastener in accordance with Claim 1 wherein said filler material spans the distance between said leg portions.

3. A staple fastener in accordance with Claim 1 wherein said staple fastener is V-shaped.

4. A staple fastener in accordance with Claim l wherein said staple fastener is W-shaped.

5. A staple fastener in accordance with Claim 1 wherein said staple is U-shaped.

6. A staple fastener in accordance with Claim 1 wherein said filler material includes a colored material.

7. A method of driving a staple fastener into a substrate and to filling a cavity with filler material, comprising the steps of : providing a staple fastener having at least two longitudinally extending leg portions, said leg portions being interconnected at one end thereof, said leg portions being separated and defining a space therebetween, said staple fastener having an extrudable filler material located in and at least partially filling said space; driving said staple fastener into a substrate, said substrate having an outer surface, whereby a cavity is formed on said outer surface of said substrate; extruding the filler material from between the legs as the staple fastener is being driven into the cavity; and tamping said filler material whereby said cavity is substantially filled with said filler material and said filler material generally conforms to said surface of said substrate.

8. A method in accordance with Claim 7 wherein the staple is driven manually with a hammer.

9. A method in accordance with Claim 7 wherein the step of driving the staple fastener comprises operating a power tool to drive the staple into the substrate, and the step of tamping the material comprises use of the same power tool that drives the staple fastener.

10. A method in accordance with Claim 9 wherein the operating of the power tool comprises the steps holding a barrel of the power tool against the substrate and actuating a first drive plunger to drive the staple fastener into the substrate and actuating a second plunger to tamp the filler material.

11. A strip of staple fasteners comprising: a plurality of staple fasteners, each staple fastener including at least two longitudinally extending leg portions, said leg portions being interconnected at one end thereof, said leg portions being separated and defining a space between said staple fasteners; an extrudable filler material located in and at least partially filling said space between said leg portions of said staple fasteners; and a material joining adjacent staple fasteners together to form the strip.

12. A strip of staple fasteners in accordance with Claim 11 including a sealant material that substantially coats said filler material.

13. A power tool for driving fasteners into a substrate below a surface thereof and for driving a filler material over the fasteners in the substrate, the power tool comprising: a fastener driver for driving one of the fasteners into the substrate and leaving a cavity in the substrate above the fasteners driven therein; a filler material driver for driving filler material into the cavity above the fastener driven into the substrate; and an actuator for actuating the fastener driver to first drive the fastener into the substrate and for actuating the filler material driver to next drive the filler material into the cavity above the fastener to cover the driven fastener with filler material .

14. The power tool of Claim 13 including a shoe to smooth the filler material to be substantially level with the substrate surface into which the fastener is driven.

15. The power tool of Claim 14 wherein the shoe includes a scraping edge for engaging the substrate surface and being moved across the surface and over the cavity to remove excess filler material covering the fastener in the substrate.

16. The power tool of Claim 13 wherein the fasteners are in a strip form with each fastener carrying a predetermined amount of filler material to fill the cavity formed above the driven staple fastener, and the filler material includes a shear improving additive so that actuation of the driver causes one of the fasteners in the strip to break off therefrom with the filler material carried by the driven fastener shearing from the filler material in the next adjacent fastener in the strip so that substantially the pre¬ determined amount of filler material is taken with the fastener being driven.

17. A pneumatic power tool for driving fasteners into a surface of a substrate and for driving filler material into a cavity formed above the fastener in the substrate surface, the power tool comprising: a fastener driver actuated by pressurized air for driving the fastener into the substrate surface; a filler material driver actuated by pressurized air for driving the filler material into the cavity for covering the fastener in the substrate; valve mechanisms for regulating the flow of pressurized air to the fastener driver and the filler material driver; and an actuator which actuates the valve mechanisms for operating the fastener driver and the filler material driver to first drive a fastener into the substrate with the fastener driver and to next drive the filler material into the cavity over the driven fastener with the filler material driver.

18. An apparatus for driving a staple into a substrate below the surface thereof and filling a cavity formed in the surface of the substrate over the staple driven into the substrate with a filler material carried by the staple, the apparatus comprising: a body including a handle for orienting the apparatus in position over the substrate into which the staple is to be driven; a staple cartridge in which staples are loaded; a staple driving mechanism including a primary plunger and a primary shaft with the primary plunger mounted for sliding movement in the primary shaft, the primary shaft receiving the staple from the cartridge with the primary plunger retracted over the staple in an inoperative position in the primary shaft; a cavity filling mechanism including a secondary plunger and a secondary shaft with the secondary plunger mounted for sliding movement in the secondary shaft; a filler opening of the secondary shaft, the filler material of the staple being extruded into the filler opening as an incident of the movement of the primary plunger from its inoperative position retracted over the staple to be driven to an operative position fully extended through the primary shaft to drive the staple through the primary shaft and into the substrate with the secondary plunger being in an inoperative position retracted in the secondary shaft; and an actuator on the body for actuating the primary and secondary plungers for reciprocating movement in their respective shafts with operation of the actuator causing the secondary plunger to be extended down the secondary shaft from the inoperative retracted position to an operative position extended through the filler opening to push the filler material therein out of the opening and into the cavity above the staple.

19. A pneumatic power tool in accordance with Claim 18 wherein the filler material driver comprises a horizontal air cylinder and a gear mechanism driven by the air cylinder to drive the secondary plunger.

20. A method of driving fasteners with a portable power tool into a substrate below a surface thereof and of filling a cavity formed over the fastener in the substrate surface with a filler material, the method comprising the steps of: positioning the power tool over the substrate at several positions along the substrate; driving the fasteners into the substrate with a power tool; driving filler material into the cavities in the substrate over the fasteners to cover the fasteners with filler material with the power tool; and leveling the filler material with the power tool so that the filler material in the cavity is substantially level with the substrate surface.

21. The method of Claim 20 wherein the fasteners are staples which are carrying filler and which are in a cartridge, including the step of: automatically feeding staples with filler material from the cartridge and driving them by the power tool.