Abstract:
A cutting head for a string trimmer, the cutting head being rotationally driven through a drive shaft, the cutting head comprising a bowl; a trimmer string secured to the bowl; and a blade attached to the outer circumference of the bowl.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 61/386,301, filed Sep. 24, 2010, for “BLADE ASSEMBLY FOR WEED TRIMMER MACHINES,” which is incorporated in its entirety herein by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    This invention relates to string trimmer and more specifically to a cutting head for a string trimmer. 
       BACKGROUND 
       [0003]    A string trimmer (“weed whacker”) is a handheld device which uses a flexible line (“trimmer string”) to cut grass and other vegetation close to objects such as trees or pavement. 
         [0004]    Typically, weed whackers comprise a cutting head at the end of a long shaft, and a handle. A trigger on the handle controls the speed of the cutting head containing trimmer string. The weed whacker may be powered by an internal combustion engine, an electric motor or a battery. Cutting is performed by the trimmer string which becomes stiff and extends horizontally outward as a result of centripetal forces when the cutting head rotates. The faster the cutting head rotates, the stiffer the trimmer string becomes. The cutting head often includes a safety shield on the user side and a rotating hub, or spool. 
         [0005]    Many users find weed whackers difficult to operate and inefficient. Often, trimmer string must be hand-wound onto a spool before use. During use, the trimmer string may break off and the user may need to release additional trimmer string to replace the spent portion. Trimmer string may also become tangled or may break apart inside the safety shield. Trimmer string is often inadequate to cut thick vegetation and a user must switch between multiple gardening tools. Gardening often requires saw blades for cutting thick vegetation and earth tilling functions which are not available in ordinary weed whackers. 
       SUMMARY OF THE PRESENT INVENTION 
       [0006]    A cutting head for a string trimmer, the cutting head being rotationally driven through a drive shaft, the cutting head comprising a bowl, at least one trimmer string secured to the bowl is presented. The cutting head provides at least one blade attached to the outer circumference of the bowl, wherein the blades are angled downward away from the trimmer strings. The cutting head, in accordance with one embodiment, further comprising at least one trimmer string mount, the trimmer string mount being secured to the top surface of the bowl and including at least one hole for attachment of the trimmer string a vertical distance above the top surface of the bowl, the trimmer string mount positioned to operate as an agitator for dispersing vegetation. The cutting head, in some variations, includes a bottom fastener ring for clamping the blade between the outer circumference of the bowl and the bottom fastener ring. In accordance with one variation, tilting the bowl adjusts the downward angle of the blades, and the height of the bowl raises the blades a distance above a cutting surface. The blade, in accordance with one variation, is composed of a spark free material. In accordance with one variation, the blade is composed of stainless steel. The blade, in accordance with one variation, is removable. In accordance with one variation, the blade is interchangeable. The blade, in accordance with one variation, is coated with ceramic wear resistant coating. The trimmer string, in accordance with one variation, is composed of nylon. The trimmer string, in accordance with one variation, is secured to the top surface of the outer diameter of the bowl. The trimmer string, in accordance with one variation, is secured to the bottom surface of the outer diameter of the bowl. In accordance with one variation, the trimmer string and the blade cut a single piece of vegetation together. 
         [0007]    In one embodiment, a cutting head for a string trimmer, the cutting head being rotationally driven through a drive shaft, the cutting head comprising a bowl, a trimmer string secured to the bowl, and a removable attachment attached to the outer circumference of the bowl is presented. The removable attachment, in accordance with one embodiment, includes a stainless steel brush. The removable attachment, in accordance with one embodiment, includes a fiber brush. The removable attachment, in accordance with one embodiment, includes a fine tooth manicuring blade. The removable attachment, in accordance with one embodiment, includes a flat toothless trimmer blade. The removable attachment, in accordance with one embodiment, includes a blower fan blade. The cutting head, in accordance with one embodiment, further comprises a trimmer string mount, the trimmer string mount being secured to the top surface of the bowl and including a hole for attachment of the trimmer string a vertical distance above the top surface of the bowl, the trimmer string mount positioned to operate as an agitator for dispersing vegetation. The cutting head, in some variations, includes a bottom fastener ring for clamping the attachment between the outer circumference of the bowl and the bottom fastener ring. In accordance with one variation, tilting the bowl adjusts the downward angle of the blade, and the height of the bowl raises the blade a distance above a cutting surface. The attachment, in accordance with one variation, is composed of a spark free material. In accordance with one variation, the attachment is composed of stainless steel. The attachment, in accordance with one variation, is removable. In accordance with one variation, the attachment is interchangeable. The attachment, in accordance with one variation, is coated with ceramic wear resistant coating. The trimmer strings, in accordance with one variation, are composed of nylon. The trimmer strings, in accordance with one variation, are secured to the top surface of the outer diameter of the bowl. The trimmer strings, in accordance with one variation, are secured to the bottom surface of the outer diameter of the bowl. In accordance with one variation, the trimmer string and the attachment cut a single piece of vegetation together. 
         [0008]    In one embodiment, a cutting head for a string trimmer, the cutting head being rotationally driven through a drive shaft, the cutting head comprising a generally cylindrical disc including a ring of downward facing blades and a bowl secured to the bottom of the generally cylindrical disc is presented. The cutting head provides at least one agitator mounted on the top surface of the generally cylindrical disc. In accordance with one embodiment, the cutting head is configured to be attached to a machine comprising trimmer strings. In accordance with one variation, tilting the bowl adjusts the downward angle of the blade, and the height of the bowl raises the blade a distance above a cutting surface. In accordance with one variation, the blade is composed of a spark free material. In accordance with one variation, the blade is composed of stainless steel. In accordance with one variation, the blade is removable. In accordance with one variation, the blade is interchangeable. The blade, in accordance with one variation, is coated with ceramic wear resistant coating. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1  is a front elevational view of a string trimmer. 
           [0010]      FIG. 2  is a front unassembled elevational view of a cutting head for a string trimmer according to an embodiment of the present invention. 
           [0011]      FIG. 3  is an assembled elevational view of the cutting head of  FIG. 2  according to an embodiment of the present invention. 
           [0012]      FIG. 4A  is a front elevational view of a cutting head according to an embodiment of the present invention. 
           [0013]      FIG. 4B  is a side view of the cutting head of  FIG. 4A  according to an embodiment of the present invention. 
           [0014]      FIG. 4C  is top view of the cutting head of  FIG. 4A  according to an embodiment of the present invention. 
           [0015]      FIG. 5A  is a top view of the bowl of  FIG. 4A . according to an embodiment of the present invention. 
           [0016]      FIG. 5B  is an elevational view of the bowl of  FIG. 4A  according to an embodiment of the present invention. 
           [0017]      FIG. 6  is a side view of the cutting head of  FIG. 2  showing clamping of the blade according to an embodiment of the present invention. 
           [0018]      FIG. 7  is a front elevational view of the cutting head of  FIG. 2  showing the tail whip effect according to an embodiment of the present invention. 
           [0019]      FIG. 8  is a partial side view of the cutting head of  FIG. 2  showing string trimmer mounts according to an embodiment of the present invention. 
           [0020]      FIG. 9  is a front elevational view of the cutting head of  FIG. 2  wherein the bowl is inverted according to an embodiment of the present invention. 
           [0021]      FIG. 10  is a side view of a cutting head of  FIG. 2  showing the bowl acting as a fulcrum to control the downward angle of the blades according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    There is a need for cutting heads for string trimmers, which provide trimmer strings as well as saw blades for cutting thick vegetation and earth tilling functions in one string trimmer machine. 
         [0023]    In accordance with some embodiments, a cutting head for a string trimmer having the ability to perform trimmer string, saw blade and earth tiller functions in one machine is provided. 
         [0024]    In accordance with some embodiments, a cutting head for a string trimmer having the ability to adjust a downward angle of earth tilling blades through tilting a bowl of the cutting head is provided. 
         [0025]    In accordance with some embodiments, a cutting head for a string trimmer having the ability to agitate vegetation and provide more efficient cutting through the use of agitators is provided. 
         [0026]    In accordance with some embodiments, a cutting head for a string trimmer having removable blades which are interchangeable and may be replaced with various attachments is provided. 
         [0027]    In accordance with some embodiments, a cutting head for a string trimmer having the ability to utilize trimmer strings and blades simultaneously to more efficiently cut vegetation is provided. 
         [0028]    In accordance with some embodiments, a cutting head for a string trimmer having the ability to be mounted to a string trimmer machine with a bowl of the cutting head either upward facing or downward facing is provided. 
         [0029]    Referring now to  FIG. 1 , shown is a front elevational view of a string trimmer  10 , including a handle  12  having a trigger  14 , a power pack  16 , a shaft  18 , a cutting head  20 , and a safety shield  22 . 
         [0030]    The power pack  16  and handle  12  including the trigger  14  are attached to the shaft  18 . The shaft  18  is connected to the cutting head  20  and the safety shield  22 . 
         [0031]    In operation, the cutting head  20  is powered by the power pack  16 . The rotational speed of the cutting head  20  is adjusted by the trigger  14  on the handle  12 . The safety shield  22  prevents cut vegetation from flying upward. 
         [0032]    Referring to  FIG. 2 , shown is a front unassembled elevational view of a cutting head for a string trimmer  30 , including a generally cylindrical bowl  32 , trimmer strings  34 , blades  36 , trimmer string mounts  38 , a bottom fastener ring  40 , trimmer string mount screws  40 , an adapter washer  44 , and a nut and washer adapter kit  46 . 
         [0033]    The trimmer strings  34  are attached to the generally cylindrical bowl  32  by the trimmer string mounts  38  and the trimmer string mount screws  42 . The blades  36  are clamped between the outer circumference of the bowl  32  and the bottom fasten ring  40 . The adapter washer  44  and nut and washer adapter kit  46  secure the bowl  32  and bottom fastener ring  40  together. 
         [0034]    In operation, as the cutting head  30  is rotated, the trimmer strings  34  become stiff and extend outward to cut vegetation. The blades  36  also cut vegetation and may cut thicker vegetation than may be cut by the trimmer strings  34 . The bowl  32  acts as a fulcrum to provide a user with control over the downward angle of the blades  36  into the earth when earth tilling functions are desired. The blades  36  may extend only slightly into the earth when edger functions are desired. For example, tilting the bowl  32  at a forty-five degree angle may cause the blades  36  to extend half of the blade length into the earth. Tilting the bowl  32  at a thirty degree angle may cause the blades  36  to extend one-quarter of the blade length into the earth. The height of the bowl  32  raises the blades  36  a distance above a cutting surface. The blades  36  and trimmer strings  34  also work together to produce a “tail whip effect,” wherein the trimmer strings  34  wrap around or whip around thicker vegetation to bring the thicker vegetation into the blades  36 . Veins located in the center of the bowl  32  act to blow grass and debris off of the bowl  32  and blades  36 . 
         [0035]    Referring to  FIG. 3 , shown is an assembled elevational view of the cutting head of  FIG. 2 . 
         [0036]    Referring to  FIGS. 4A-4C , shown are front elevational, side and top view of a cutting head  50 , including a generally cylindrical disc  52  including a ring of downward facing blades  54 , at least one agitator  56 , and a generally cylindrical bowl  58 . 
         [0037]    The ring of downward facing blades  54  are attached to outer circumference of the generally cylindrical disc  52 . The generally cylindrical bowl  58  is attached to the bottom surface of the generally cylindrical disc  52 . The at least one agitator  56  is attached to the top surface of the generally cylindrical disc  52 . 
         [0038]    In operation, as the cutting head  50  is rotated, the blades  54  cut vegetation. The bowl  58  acts as a fulcrum to provide a user with control over the downward angle of the blades  54  into the earth when earth tilling functions are desired. The blades  54  may extend only slightly into the earth when edger functions are desired. For example, tilting the bowl  58  at a forty-five degree angle may cause the blades  54  to extend half of the blade length into the earth. Tilting the bowl  58  at a thirty degree angle may cause the blades  54  to extend one-quarter of the blade length into the earth. The height of the bowl  58  raises the blades  54  a distance above a cutting surface. 
         [0039]    Referring to  FIGS. 5A-B , shown is a top and an elevational view of the bowl of  FIG. 4A . 
         [0040]    Referring to  FIG. 6 , shown is a partial side view of the cutting head of  FIG. 2  showing clamping of the blade. 
         [0041]    Referring to  FIG. 7 , shown is a front elevational view of the cutting head of  FIG. 2  showing the tail whip effect. 
         [0042]    Referring to  FIG. 8 , shown is a partial side view of the cutting head of  FIG. 2  showing trimmer mounts. 
         [0043]    Referring to  FIG. 9 , shown is a front elevational view of the cutting head of  FIG. 2  wherein the bowl is inverted according to an embodiment of the present invention. 
         [0044]    Referring to  FIG. 10 , shown is a side view of a cutting head of  FIG. 2  showing the bowl acting as a fulcrum to control the downward angle of the blades. 
         [0045]    While the invention has been described in detail with reference to preferred embodiments, it is understood that variations and modifications thereof may be made without departing from the true spirit and scope of the invention.