Abstract:
A single tool functioning as a screwdriver, a socket wrench and a brush. A shaft serves as an element of a screwdriver, the shaft of a socket wrench and a handle and support for a brush; In one embodiment, a tube with sockets at both ends is attached at its center to one end of a shaft that is also slidably disposed within an axial channel through a brush, and the other end of the shaft is shaped as a screwdriver blade.

Description:
The present invention relates to multi-function tools for facilitating mechanical operations. More particularly, the present invention relates to tools for servicing chain saws. 
     BACKGROUND OF INVENTION 
     Chain saws are heavy-duty devices for cutting wood, particularly trimming and removing trees as required to maintain a house or fell trees in lumbering. Chain saws are also used in the creation of works of art such as wood carvings and ice sculptures. While chain saws reduce the hard work of such tasks, they unfortunately require significant maintenance and repair. Chain saws are prone to clogged fuel lines, clogged air, fuel and oil filters, hard starting engines and under tensioned chains. 
     A chain saw functions by cutting material from a work piece, thus forming sawdust and chips, and hence its very use creates debris which tends to accumulate on various parts of the chain saw. Unfortunately, the debris created by the chain saw is one of the major causes of malfunction of the chain saw, particularly air, fuel and oil related problems. 
     Many chain saw users recognize that the dust, dirt and debris produced by the chain saw is a threat to trouble-free operation of the chain saw, and they carry a brush in their toolboxes which can be used to clean the caps on the gasoline tank and oil reservoir and the areas around the caps, before opening the caps. Such brushes are effective in preventing saw dust, chips and other debris from entering the gasoline tank or oil tank; however, unattached brushes tend to be unavailable. Such brushes tend to get lost or fall to the ground when the chain saw is being used on a scaffold or the like. Mounting a brush on the chain saw will not solve this problem as illustrated by U.S. Pat. No. 4,748,745 to R. G. Woodbridge entitled Chain Saw Brush For Cleaning Saw Cuts. This patent discloses the combination of a chain saw and a brush mounted thereon, but the brush can only be used on surfaces other than that of the chain saw itself. 
     Accordingly, it is an object of the present invention to provide a brush for brushing a chain saw which will tend to be accessible when servicing the chain saw. 
     A common problem encountered by those who use chain saws is that the chain of the saw loosens during performance of a job and the chain must be tightened before the job is completed. The chain rides on the perimeter of a blade which is mounted on the frame of the saw confronting a sprocket for driving the chain, the blade extending outwardly from the sprocket. U.S. Pat. No. 2,765,821 to L. M. Strunk discloses a means to adjust the distance between the chain sprocket and the blade to adjust the tension on the chain. This 1956 patent discloses a chain saw blade tensioning device in which the blade of the saw has a slot extending therein on the longitudinal axis of the blade and confronting the chain sprocket, and a pair of threaded studs extend through the slot and are engaged by a pair of nuts that retain the blade in position relative to the sprocket. The chain may be tightened by loosening the nuts, moving the blade further away from the chain sprocket, and thereafter tightening the nuts. Similar saw tensioning devices that employ nuts to secure the blade of the saw at a proper distance from the chain sprocket are in use on most of the chain saws today . . . . 
     Accordingly, almost all chain saw users carry a tool in their tool boxes to release the nuts that hold the blade of the saw in order to adjust the tension on the chain and to tighten the nuts to retain the tension on the chain. Also, most chain saw users carry a screwdriver in their tool boxes to engage the many devices on a chain saw that are facilitated by a screwdriver, such as loosening caps on gasoline and oil ports. For convenience, a combination screwdriver and wrench has been provided for servicing chain saws, and this device is generally referred to as a “scrench.” It has a tube with sockets for nuts of different sizes at opposite ends, a shaft extending normally from the tube and a screwdriver blade disposed at the end of the shaft opposite the tube. The two sockets at opposite ends of the tube are designed to engage nuts of two different sizes that are found on chain saws, and the screwdriver blade is designed to engage air filter closures and gasoline and oil caps found on chain saws. 
     It is an object of the present invention to provide a tool for use with a chain saw that functions as a brush, a nut driver and a screw driver. 
     Further, it is an object of the present invention to provide a tool that is a combination of a wrench, a screwdriver and a brush in which the screwdriver function is facilitated by the wrench and the wrench and brush functions are facilitated by the screwdriver. 
     Further, it is an object of the present invention to provide a tool that is a combination of a wrench, a screwdriver and a brush in which the screwdriver function is not impaired by the wrench or brush, the wrench function is not impaired by the screwdriver or brush and the brush function is not impaired by the wrench or screwdriver. 
     SUMMARY OF INVENTION 
     The objects of this invention are achieved by a tool that provides a nut driver function, a screw driver function and a brushing function. In the preferred embodiment, a tool is provided with an elongated tube that has recesses at opposite ends thereof forming sockets of different sizes for engaging nuts, a shaft having one end mounted on the tube and extending from the tube to a screwdriver blade at the other end, and a brush slidably disposed between two spaced positions on the shaft. This compact unitary tool performs the functions of a nut driver, a screwdriver and a brush. 
     In each case the performance of the function is not adversely affected by the presence of equipment for performing one or more of the other functions of the tool. Further, each of the functions of the tool is aided by the presence of equipment for performing one or more of the other functions, as indicated by Table 1 hereinafter. 
     
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Effect On 
                   
                   
               
               
                 Function 
                 Screwdriver 
                 Effect on Nut Driver 
                 Effect on Brush 
               
               
                   
               
             
             
               
                 Screwdriver 
                   
                 Shaft provides torque 
                 Shaft forms handle 
               
               
                   
                   
                   
                 Blade is end stop 
               
               
                 Nut Driver 
                 Tube is 
                   
                 Stop at end of shaft 
               
               
                   
                 torque bar 
               
               
                 Brush 
                 No 
                 No significant effect 
               
               
                   
                 significant 
               
               
                   
                 effect 
               
               
                   
               
             
          
         
       
     
     The invention also includes a second embodiment in which the screwdriver device described above is replaced by screwdriver device that is designed to couple to screws with multiple slots or non-planar slot configurations, such as Phillips screws. Screwdrivers for such screws generally have cylindrical shafts and accordingly a screwdriver for such screw heads does not have a shaft with protrusions that will form a stop to retain the brush on the shaft. In this embodiment, the shaft carries a ring that surrounds the shaft and protrudes therefrom sufficiently to engage the brush and form a stop. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       For a more complete understanding of the invention, reference is made to the accompanying drawings, in which: 
         FIG. 1  is an elevational view of a tool constructed according to the present invention with the brush retracted for use as a screwdriver and illustrating in dotted lines the brush in position for use as a brush; 
         FIG. 2  is an elevational view illustrating the tool of  FIG. 1  positioned to engage the cap on the gasoline port of a chain saw with the nut driver, the brush being positioned confronting the screwdriver blade; 
         FIG. 3  is an elevation of view of the tool of  FIG. 1  configured for use of the brush function, the brush being positioned confronting the screwdriver blade; 
         FIG. 4  is a sectional view taken along the line  4 - 4  of  FIG. 1 ; and 
         FIG. 5  is an elevational view of a tool that constitutes another embodiment of the present invention, the brush being retracted for use of the tool as a screwdriver. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 through 3  illustrate a preferred embodiment of the present invention. A multipurpose tool according to the present invention has an elongated shaft  10  that extends between a screw driving device  12  and a nut driving device  14 . The shaft  10  is constructed of rigid material such as iron or steel, and is linear. In the illustrated construction, the shaft  10  has a circular cross-section, but it could also be non-circular. The screw driving device  12  in the illustrated construction is a blade  16  that is integral with the shaft  10  and extends outwardly from the end  18  thereof opposite the nut driving device  14 . 
     The nut driving device  14  is mounted on the end  20  of the shaft  10  opposite the screw driving device  12 . In the illustrated construction, the nut driving device  14  has a body in the form of an elongated tube  22  with a central axis  23 . The tube  22  is mounted on the end  20  of the shaft  10  normal to the axis of the shaft and is provided with socket forming recesses  24  and  26  at opposite ends of the tube. The recesses  24  and  26  have walls  28  consisting of flat segments  30  that are substantially parallel to the central axis of the tube  22 , and in each of the recesses  24  and  26 , each segment  30  is attached to adjacent segments on axes parallel to the central axis of the shaft and of equal length, whereby each recess  24  and  26  forms a socket that is adapted to engage a nut. The nut driving device  14  may use a body of another shape, such as a sphere, or the central axis of the tube may not be perpendicular to the axis of the shaft, but the central axes of the recesses  24  and  26  that form the sockets of a wrench should be preferably substantially normal to the axis of the shaft  10  to optimally transfer torque from the shaft to the wrench sockets. 
     As best illustrated in  FIGS. 1 and 4 , a brush  32  is slidably mounted on the shaft  10  by a base  34 , and the brush has a plurality of bristles  36  mounted at one end thereof on the base, the bristles  36  extending outwardly from the base  34  and away from the end  20  of the shaft  10 . The base  34  has a generally cylindrical shape with a central axis of elongation. A channel  38  extends coaxially through the base  34  and slidably accommodates the shaft  10 . The base  34  also has an annular recess  40  extending therein from the end thereof opposite the nut driving device  14  and coaxial with the shaft  10 . One end of each of the bristles  36  is disposed within the annular recess  40  and anchored therein by a mass of adhesive cement  42 , each of the bristles extending from the base  34  generally parallel to the axis of the shaft  10 . A circular cap  44  having a central channel  46  coaxial with the channel  38  of the base  34  is mounted by cement (not shown) on the end of the base  34  opposite the annular recess  40 . 
     In the preferred construction described above, the screwdriver blade  16  has a pair of flat surfaces  48  which depend from the end  18  of the shaft  10  at a slight angle to the central axis of the shaft and terminate in a thin straight edge  50  that is disposed normal to the axis of the shaft. The blade  16  also has a transverse axis  52  parallel to the flat surfaces  48  and disposed generally centrally between the straight edge  50  and the end  18  of the shaft  10 . The transverse axis  52  is sufficiently longer than the cross-sectional length (or diameter) of the shaft  10  to form a stop against translation of the brush  32  from the shaft  10 . In one construction, the shaft  10  is cylindrical and has a diameter of 5/16 inch. The channel  46  through the base  34  and cap  44  is also cylindrical having a diameter of about ⅜ inch, but the transverse axis  52  of the screwdriver blade  16  is approximately 7/16 inch long and forms a stop against translation of the brush  32  over the blade and off of the shaft  10 . In this construction, the brush  32  is 4¼ inches long, and the shaft  10  is 6½ inches long, and when the brush  32  is translated to the stop position adjacent to the blade  16 , there are approximately 4 inches between the nut driving device  14  and the cap  44  off the brush  32 . As indicated in  FIG. 3 , this space of 4 inches is sufficient for a chain saw operator to hold the brush  32  free of interference by the nut driving device  14  . . . . Also, as illustrated in  FIG. 2 , with the brush  32  in this position, the nut driving device  14  is in position to engage a nut or cap of a fuel or oil port on a chain saw  54 . With the tool in this configuration, the entire length of the shaft  10  can be utilized to generate torque on the tube  24  for loosening or tightening a nut or the like. 
       FIG. 5  illustrates another embodiment of the present invention. Powered screwdrivers are generally designed to engage screw heads provided with more than one slot for coupling the screw to the screwdriver, and  FIG. 5  illustrates a tool according to the present invention that is adapted to engage such screw heads. Except for the screw driving device  12 A and stop at the end  18  of the shaft  10 , the embodiment of  FIG. 5  is identical to that of  FIG. 1 , and the same reference numerals and description presented above apply to  FIG. 5 . 
     This screw driver device  12 A is integral with the shaft  10 , and consists of one or more slots  56  that extend from at least the axis of the shaft  10  to the perimeter of the shaft. The slots  56  may traverse the diameter of the shaft  10 , or be radial such as required to accommodate Phillips screws. Since the diameter of the screw driver device  12 A is the same as the shaft  12  throughout its length, there is no protrusion to function as a stop to prevent the brush  32  from being translated off of the end  18  of the shaft. A stop is provided by securing a ring  58  on the shaft  10  at the end  18  of the shaft  10 . The outer diameter of the ring  58  is greater than the diameter of the channel  46  in the brush  32 , and the ring and shaft form a stop to translation of the brush  32  at the end  18  of the shaft  10 . 
     The ring  58  may be constructed of metal and secured to the shaft  10  by welding or the like. Also, the ring  58  may be constructed of plastic and cemented on the shaft  10 . The ring may also be a strip of tape with an adhesive backing on one side, the tape being wound about the shaft  10  to form the ring  58 . Forming the ring  58  with adhesive tape permits replacement of the brush  32  should it become worn, or the addition of a brush to a tool with a screw driver function and a nut driver function but without a brush function. 
     Those skilled in the art will devise additional constructions within the scope of the present invention. It is therefore intended that the scope of this invention be not limited by the foregoing specification, but rather only by the appended claims.