Abstract:
A construction worker may adapt a reciprocating handheld power saw to multiple additional applications including brushing, scraping, sanding, and polishing. A simple adapter is attached to the power tool in place of a saw blade. Multiple attachments for the various applications are easily press-fit onto the adapter.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/508,461, filed Oct. 2, 2003. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of handheld power tools, specifically to the adaptation of linearly reciprocating handheld power tools to multiple uses. 
     2. Prior Art 
     A reciprocating handheld power saw is a tool that is widely used by plumbers, electricians, carpenters, and other workers in the construction industry. (See, for example, the listing for Milwaukee 10 Amp Sawzall Reciprocating Saw in “Milwaukee Product Catalog”, Milwaukee Electric Tool Corporation, [retrieved on 2003 Aug. 21], retrieved from &lt;URL:http://www.milwaukeeconnect.com/html/index.html&gt;.) The saw blades of such tools are generally removable. This makes it possible to apply the linearly reciprocating motion of such a power tool to other applications besides cutting with a saw. 
     In U.S. Pat. No. 6,142,715, “File Adapter for Power Saw Tool”, to Fontaine, a reciprocating handheld power tool is adapted to become a power filing device. The disclosed apparatus requires two points of connection between the filing adapter and the power tool. A bar holding the file is connected to the reciprocating portion of the power tool. A bracket for guiding the reciprocating file is connected to the body of the power tool. The result is a relatively complex construction dedicated to the application of power filing. 
     In U.S. Pat. No. 4,893,437, “Power Sanding Adapter for Jigsaws”, to Doherty, a reciprocating handheld power tool is adapted to scrape or sand wallpaper from a wall. The disclosed apparatus requires two points of connection between the sanding adapter and the power tool. A bar holding a scraping or sanding head is connected to the reciprocating portion of the power tool. A bracket for guiding the reciprocating portion and providing additional hand-holds is connected to the body of the power tool. The result is a relatively complex construction dedicated to the application of scraping or sanding. 
     Each of the two patented inventions described above are dedicated to a narrow range of application. Each requires a relatively complex connection to a power tool so that reconfiguration of the power tool for multiple different applications in the field is cumbersome and inconvenient. 
     3. Objects and Advantages 
     The present invention adapts a linearly reciprocating handheld power tool to multiple applications including brushing, scraping, sanding, and polishing. It requires only a single point of connection between an attachment and the power tool. It enables very fast and convenient reconfiguration for the multiple supported applications. 
     SUMMARY OF THE INVENTION 
     An adapter connects to a reciprocating handheld power tool at the single point of connection typically used to attach a saw blade. The adapter provides a flange that fits into multiple different application attachments using a simple and convenient press-fit mechanism. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an adapter with a brush attachment connected to a reciprocating handheld power tool. 
         FIG. 2  is a perspective view of an adapter. 
         FIG. 3  is a close-up view of the universal tang protruding from the adapter where it connects to a reciprocating handheld power tool. 
         FIG. 4  is three views of the base of an attachment. 
         FIG. 5  is a scraper attachment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Structure and Operation 
     The present invention adds multiple additional functions to a reciprocating handheld power tool, such as the Milwaukee Sawzall. (See, for example, the listing for Milwaukee 10 Amp Sawzall Reciprocating Saw in “Milwaukee Product Catalog”, Milwaukee Electric Tool Corporation, [retrieved on 2003 Aug. 21], retrieved from &lt;URL:http://www.milwaukeeconnect.com/html/index.html&gt;.) These tools are principally used with saw blades by construction workers for rough cutting applications. 
       FIG. 1  shows a typical reciprocating handheld power tool  10  configured with a wire brush attachment  25  instead of a common saw blade attachment. An operator typically places one hand on a hand grip  12  at the rear of power tool  10 , places the other hand under the middle of power tool  10 , and presses a trigger  14 . This activates the in-and-out motion of a reciprocating member  15  of power tool  10 , which causes wire brush attachment  25  to move back and forth in a scrubbing action on any surface on which it is placed. Power tool  10  thus substitutes for the human muscle power applied in manual brushing. One important use for this configuration is the removal of old paint from woodwork or other surfaces. 
       FIG. 1  shows that wire brush attachment  25  is connected to reciprocating member  15  using an adapter  20 . Adapter  20  is shown separately in  FIG. 2 , displayed in an inverted position relative to  FIG. 1 . Adapter  20  has an overall length of 21 centimeters. It is fabricated from three parts: a flat metal blade  30 , a main housing  35 , and a flange molding  40 . 
     Blade  30  is 0.18 centimeters thick and 9.9 centimeters long. A length of 7.2 centimeters of blade  30  is molded inside housing  35 . This portion of blade  30  is cut in a pattern of square teeth for firm anchoring. A length of 2.7 centimeters of blade  30  protrudes from housing  35 . This portion of blade  30  fits into reciprocating member  15  using the de-facto standard shape and size of the ½-inch universal tang (or shank) used at the connecting end of all Sawzall blades and compatible with many products competitive with the Sawzall. (See, for example, the listing for Super Sawzall Blade, 6 Teeth per Inch, 9 in. Length, in “Milwaukee Product Catalog”, Milwaukee Electric Tool Corporation, [retrieved on 2003 Aug. 21], retrieved from &lt;URL:http://www.milwaukeeconnect.com/html/index.html&gt;.) A close-up view of this end of blade  30  is shown in  FIG. 3 . 
     Main housing  35  is composed of molded plastic. The overall length of housing  35  is 18 centimeters. The width of housing  35  is 0.8 centimeters. Housing  35  uses two truss webs to support flange molding  40  and to handle the stress forces of operation. A heel web  37 , which is closer to the connection to power tool  10 , is composed of two curved plastic portions that protrude about 6.5 centimeters above the straight bottom portion of housing  35 . A toe web  42 , which is farther from the connection to power tool  10 , is composed of two straight plastic portions that protrude about 5.0 centimeters above the straight bottom portion of housing  35 . 
     Flange molding  40  has a flat base that is 0.7 centimeters thick by 2.0 centimeters wide by 14.5 centimeters long. Centered on the top of this base is a rectangular flange that is 0.6 centimeters tall by 0.6 centimeters wide by 12.0 centimeters long. Flange molding  40  is composed of plastic. Flange molding  40  is precision molded so that it will form a reliable press fit into a corresponding cavity  65  in base  50  (see  FIG. 4 ) of wire brush attachment  25 . Flange molding  40  may be rigidly fixed to truss webs  37  and  42  using glue, electrical welding, screws, or any other method that can handle the stress forces of operation. The plane of the flat base of flange molding  40  is angled six (6) degrees from the axis of reciprocation which runs through the length of flat blade  30  and the straight bottom portion of housing  35 . This angle allows for comfortable positioning of an operator&#39;s hands while brushing a large flat surface. 
       FIG. 4  shows details of base  50  of wire brush attachment  25  in three views: top, side, and end. Base  50  is composed of plastic. Base  50  is precision molded so that cavity  65  forms a reliable press fit with flange molding  40  of adapter  20 . 
     To form wire brush attachment  25 , stiff wire bristles are imbedded at regular intervals in the top of base  50 . However, many other useful attachments may be made from base  50  or minor variations of base  50 . Attachments may be made with brushes of various sizes, shapes, and materials. Attachments may also be made with scrapers, scouring pads, or buffing pads. Any work accomplished by a hand tool used with a reciprocating or scrubbing motion of a human arm may be eased by an attachment to a reciprocating handheld power tool according to the present invention. One example, a scraping tool attachment, is shown in  FIG. 5 . The scraping tool attachment is formed by connecting a scraper blade  55  to base  50 . The base  50  of each different attachment has a cavity, such as  65 , for a quick and easy mounting on the support flange molding  40  and removal therefrom. 
     Conclusion and Variations 
     Adapter  20  connects to a reciprocating handheld power tool at a single point of connection using a simple established standard, such as the ½-inch universal tang used with any Milwaukee Sawzall and many compatible competitive products. The quick and easy press-fit connection of flange molding  40  into cavity  65  is very convenient for operators who need to quickly change from one application to another. Thus the present invention makes multiple applications of a reciprocating handheld power tool significantly faster and more convenient than it has been with prior art. 
     As an alternative, operators who work a single application for an extended period of time may prefer to have a particular attachment permanently attached to adapter  20 . This configuration is included in the scope of the present invention. 
     The ½-inch universal tang for connection to any Milwaukee Sawzall reciprocating handheld power tool and compatible competitive products appears to be the current preferred standard for connecting saw blades to reciprocating handheld power tools. Nevertheless, the end of blade  30  which protrudes from plastic housing  35  may be readily altered to make a variation of adapter  20  which attaches to other handheld reciprocating power tools that use a connection standard different from that of the Milwaukee Sawzall. 
     In the light of these and other possible variations of the preferred embodiment, the scope of the present invention should be determined not by the specific descriptions above, but by the following claims.