Abstract:
An improved head for a vegetation trimmer has a drop-down line reservoir that remains in cooperation with the head housing when the reservoir is in a load position. The reservoir fits inside the head housing and is biased against the housing for secure use. The reservoir is rotated to unlock it from the housing, whereby it drops down to allow access to the line in the reservoir. A user can add, remove, and manipulate line as desired without the inconvenience of detachable pieces. The reservoir can be pushed back into the housing and locked into place for use. The reservoir can also be placed in an advance position and rotated to advance more line through line openings in the housing as needed.

Description:
FIELD OF INVENTION 
       [0001]    This invention relates to vegetation trimming devices. This invention relates particularly to an improved head for a vegetation trimmer. 
       BACKGROUND 
       [0002]    Vegetation trimmers typically have a trimmer head that is attached to a main shaft and connected to a motor. The trimmer head holds trimmer line, which may be either fixed-length segments of line or a spool of line that is fed through an eyelet or eyelets as needed. One advantage of spool trimmer heads over fixed-line heads is that there is no need to constantly replace the worn or broken line segments. Another advantage is that the entirety of the line can be used, while fixed-line heads contain a part of the line segment, and that part is never used to cut vegetation. 
         [0003]    One disadvantage of most spool heads is that they must be taken apart to get access to and reload the spool. Most spool heads are spring-loaded to bias the spool in the correct position within a housing, and the heads have a bolt or screw attaching the spool to the housing. When the bolt is unscrewed, the bolt, spool, and spring fall out of the housing. Parts are frequently lost, and eventually the repeated screwing and unscrewing leads to replacement of worn out parts. Further, once the parts have fallen out of the housing it is difficult to reload the spool and push it back into place without disturbing the trimmer line&#39;s coil around the spool. An improved head that provides easier access to load the spool is needed. 
         [0004]    Some known spool heads attempt to resolve this problem by allowing replacement line to be fed into the head through an eyelet. The end of the line typically fits into a catch and the spool is rotated, winding the line onto the spool. On these heads, the user cannot see the spool or guide the line onto the spool with his fingers. It is difficult to get the line properly positioned for winding, and the user cannot detect and fix winding problems, such as twists and crossovers that can damage the line or inhibit advance of the line for use. An improved head that allows the user to monitor the winding and manually fix winding problems is needed. 
         [0005]    Therefore, it is an object of this invention to provide an improved vegetation trimmer head having a reservoir of line that can be reloaded without taking apart the head. It is a further object that the user be able to see the line as it is added to the reservoir. It is a further object that the user be able to manipulate the line in the reservoir with his fingers, as needed. 
       SUMMARY OF THE INVENTION 
       [0006]    An improved head for a vegetation trimmer has a drop-down line reservoir that remains in cooperation with the head housing when the reservoir is in a load position. The housing and reservoir are coaxial with each other and with the main shaft of the vegetation trimmer. The reservoir is an annular cylinder that fits around a shaft extending coaxially from the housing, the fit being loose enough to allow the reservoir to slide along the shaft. Flanges near the base of the shaft and on the inner surface of the reservoir prevent the reservoir from sliding completely off the shaft. A biasing member, preferably a spring, fits over the shaft between the reservoir and the top of the housing. The assembly allows the reservoir to be placed in three positions. In the use position, the reservoir is within the housing and biased from the housing by the spring. In the advance position, the reservoir remains within the housing and is manipulated so trimmer line may be advanced through one or more line openings in the housing, to the user&#39;s desired length. In the load position, the spring pushes the reservoir down the shaft until the flanges contact each other, leaving the reservoir outside the housing so line can be added, removed, or repositioned. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an exploded top perspective view of the preferred embodiment of the present invention. 
           [0008]      FIG. 2  is an exploded bottom perspective view of the preferred embodiment of the present invention. 
           [0009]      FIG. 3  is a cross-section of the preferred embodiment of the invention in the load position. 
           [0010]      FIG. 4  is a top perspective close-up view of the cross-section of  FIG. 3  showing the cooperation between the shaft flange and the arbor flange. 
           [0011]      FIG. 5  is a cross-section of the preferred embodiment of the invention in the use position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Referring to  FIGS. 1 and 2 , there is illustrated the preferred embodiment of the present invention, designated generally as  10 , which is a trimmer head for fuel- or electricity-powered vegetation trimmer. The head  10  comprises a housing  11 , a biasing member such as a spring  27 , and a reservoir  17  that holds trimmer line and fits inside the housing  11 , and is biased from the top of the housing by the biasing member. The housing  11  retains the trimmer line in the reservoir  17  and protects the trimmer line while the trimmer is in use. The housing  11  is preferably a die-cast metal cylinder, most preferably aluminum, but may alternatively be steel or molded plastic. The outer and inner diameters of the housing  11  are typical for commercial or residential vegetation trimmers, depending on the desired head  10  size. In the preferred embodiment, one or more notches  16  are integral with the housing  11  and positioned inside the housing  11  at the bottom of the housing  11 . See  FIG. 3 . The notches  16  mate with positioning pegs  23  on the reservoir  17  to retain the reservoir  17  inside the housing  11  as described below. The notches  16  are preferably substantially arrow-shaped, having a rectangular body and triangular or trapezoidal head that is wider than the body. Alternatively, the notches  16  may be other shapes that are capable of mating with the positioning pegs  23 , such as circular, tear-shaped, rectangular, square, or a combination of shapes. 
         [0013]    One or more line openings  15  are disposed through the housing  11 . A line opening  15  may be a hole, such as an eyelet, or may be a larger void functioning as a mount for a grommet  26 , as shown in  FIGS. 1 and 2 . One or more trimmer lines pass from the reservoir  17  through the line openings  15 , which may have grommets  26  that protect the trimmer line from wearing and breaking. Grommets  26  are preferably u-shaped as illustrated, with the line openings  15  appropriately sized to retain the grommets  26  in the housing  11 . In embodiments utilizing multiple line openings  15 , the line openings  15  may be uniformly spaced around the circumference of the housing  11  so that the head  10  maintains an equalized weight balance as it spins at high speeds. The line openings  15  may be the same distance or different distances from the top of the housing  11 . Preferably, there are two diametrically opposed coplanar line openings  15  in the housing  11 . 
         [0014]    The housing  11  includes a substantially cylindrical shaft  13  attached to or integral with the housing  11 . Preferably, the shaft  13  is integral with the housing  11  and is cast simultaneously with the housing  11 . Alternatively, the shaft  13  may be permanently or removably attached to the housing  11 . While other attachment means may be used, an example of permanent attachment is by adhesive, and an example of removable attachment is by mate-and-lock threads cast or molded into the housing  11  and shaft  13 . The shaft  13  is coaxial with the housing  11  and has a top end at the top of the housing  11  and a bottom end that is preferably substantially coplanar with the bottom of the housing  11 . In alternative embodiments, the shaft  13  may be longer or shorter, respectively extending or being recessed from the bottom of the housing  11 . The shaft  13  may be a solid cylinder but is preferably a rigid tube, allowing the trimmer&#39;s main shaft  30  to pass through it as described below. 
         [0015]    A shaft flange  14  encircles the shaft  13  at or near the bottom end. The shaft flange  14  is preferably integral with the shaft  13 , but alternatively may be cast separately and permanently or removably attached to the shaft  13 . The diameter of the shaft flange  14  is slightly larger than the diameter of the shaft  13 , forming a collar that contacts the arbor flange  21  as described below. The shaft flange  14  may have any profile shape, such as triangular, rectangular, trapezoidal, or semicircular, so long as the top of the shaft flange  14  is able to engage the bottom of the arbor flange  21  to prevent the reservoir  17  from sliding off of the shaft  13 . As shown in  FIGS. 3 and 4 , the shaft flange  14  preferably has a triangular profile, with the top of the shaft flange  14  being substantially perpendicular to the surface of the shaft  13 . The shaft flange  14  then tapers to allow the arbor flange  21  to easily slide over the shaft flange  14  as described below. The tapering, which may be implemented in other shapes as well as the triangular profile, is preferred but not necessary. 
         [0016]    The reservoir  17  comprises a rigid tubular arbor  18  attached to a top rim  19  and a bottom rim  22 . The arbor  18  may be made of metal or one or more polymers, and is preferably nylon. A desired amount of trimmer line is wrapped around the arbor  18  and held vertically in place by the rims  19 ,  22 . The outer diameter of the arbor  18  defines the surface onto which the trimmer line is wound. An anchor may be attached to or integral with the arbor  18 , and the trimmer line may be secured to the anchor when it is first wound onto the arbor  18 . In the preferred embodiment, the anchor is a hook  25  that is integral with and recessed in the arbor  18 . The hook  25  is open in the direction opposite the winding of the trimmer line so that a loop of the trimmer line can be secured around the hook  25  and the trimmer line can be wound onto the arbor  18 . The trimmer line is looped near its center and hooked onto the anchor. Once the trimmer line is wound, this provides two loose ends of trimmer line to be fed through the line openings  15 . Alternatively, the anchor may be a hole that accepts an end of the trimmer line, or a hook that projects out from the surface of the arbor  18 . 
         [0017]    The arbor  18  may have a single inner diameter, so that the arbor  18  has a uniform wall thickness. This inner diameter is slightly larger than the diameter of the shaft flange  14 . Preferably, however, a recess  20  is formed into the interior surface of the arbor  18  at the top end, as shown in  FIGS. 3 and 4 . This creates two inner diameters, where the first, smallest inner diameter is slightly larger than the diameter of the shaft flange  14 , and the second inner diameter is slightly larger than the diameter of the spring  27 . The spring  27  fits into the recess  20  to bias against the arbor  18  as described below. The depth of the recess  20  depends on the length of the arbor  18  and the desired amount of compression of the spring  27 . Alternatively, no recess  20  is included on the arbor  18 , and the biasing member biases against the top of the arbor  18  or against the top rim  19  described below. 
         [0018]    The arbor  18  further comprises an arbor flange  21 . The arbor flange  21  is positioned on the interior surface of the arbor  18 , and may be vertically positioned anywhere between the top and about the midpoint of the arbor  18 . The location of the arbor flange  21  determines how far the reservoir  17  will protrude from the housing  11  when the head  10  is placed in the load position as described below. Specifically, the closer to the top of the arbor  18  the arbor flange  21  is placed, the less of the reservoir  17  will be exposed in the load position. In the preferred embodiment, the arbor flange  21  is integral with the interior surface of the arbor  18 . Alternatively, the arbor flange  21  may be separately manufactured and permanently or removably attached to the arbor  18 . The diameter of the arbor flange  21  is slightly larger than the diameter of the shaft  13 , but smaller than the diameter of the shaft flange  14 . The arbor flange  21  may have any profile shape, such as triangular, rectangular, trapezoidal, or semicircular, so long as the bottom of the arbor flange  21  is able to engage the top of the shaft flange  14  to prevent the reservoir  17  from sliding off of the shaft  13 . As shown in  FIG. 4 , the arbor flange  21  preferably has a trapezoidal profile, with the bottom of the arbor flange  21  being substantially perpendicular to the interior surface of the arbor  18 . The arbor flange  21  tapers to allow the shaft flange  14  to easily slide over the arbor flange  21 , placing the reservoir  17  in cooperation with the housing  11 . See  FIG. 4 . The tapering, which may be implemented in other shapes as well as the trapezoidal profile, is preferred but not necessary. 
         [0019]    The top rim  19  is attached to or integral with the arbor  18  at the top of the arbor  18 . The top rim  19  is a rigid annular disc, preferably made of the same material as the arbor  18 . The outer diameter of the top rim is small enough to fit into the housing  11 , but large enough to retain a full reservoir of trimmer line. The inner diameter is aligned with the outer diameter of the arbor  18 . The bottom rim  22  is also a rigid annular disc and is attached to or integral with the arbor  18  at the bottom of the arbor  18 . The outer diameter of the bottom rim  22  is slightly smaller than the inner diameter of the housing  11 , and the inner diameter is aligned with the outer diameter of the arbor  18 . A series of positioning pegs  23  are spaced around the circumference of the bottom rim  22  on its outer surface, as shown in  FIGS. 1 and 2 . The positioning pegs  23  mate with the notches  16  on the interior surface of the housing  11  to hold the reservoir  17  inside the housing  11  in the use and advance positions described below. 
         [0020]    A base  24  is permanently or removably attached to the reservoir  17  at the bottom of the bottom rim  22 . The base  24  may be the same material as the parts of the reservoir  17 , but is preferably nylon and creates a protective shield against the ground and other surfaces when the vegetation trimmer is in use. The diameter of the base  24  preferably coincides with the outer diameter of the bottom rim  22 , but alternatively may be smaller or slightly larger than the bottom rim  22 . The base  24  may be circular, with a rounded profile as shown in  FIGS. 3 and 5 . The base  24  may have an aperture  29  through which the locking screw  32  and main shaft  30  may be accessed. Alternatively, the base  24  may be annular, allowing access to the shaft  13  with the base  24  attached. One or more grips  28  may be formed into the base  24 . The user may rest his fingers on the grips  28  to get a firm hold on the reservoir  17  in order to move it between positions, or to rotate it as the user loads line into the reservoir  17 . 
         [0021]    A biasing member fits inside the housing  11  between the top of the housing  11  and the reservoir  17 . The biasing member is preferably a spring  27  that fits around the shaft  13 , but alternatively may be any resilient material that can be positioned to push the reservoir  17  out of the housing  11  in the load position. In the preferred embodiment, the spring  27  is slid over the shaft  13 , and then the shaft  13  is slid into the arbor  18  until the arbor flange  21  slides over the shaft flange  14 . At this point, the spring  27  fits into the recess  20  in the arbor  18 . In alternative embodiments, the spring  27  may bias against the top rim  19  instead of the arbor  18 . The preferred spring  27  has length and compression properties so that the spring  27  is slightly compressed when the head  10  is in the load position, wherein the arbor flange  21  is in contact with the shaft flange  14  and the reservoir  17  is in its most exposed position. See  FIG. 3 . The compression in this position is sufficient to keep the flanges  14 ,  21  pressed into contact with each other. Further, the preferred spring  27  is substantially or fully compressed in the use position, wherein the mating of the positioning pegs  23  and notches  16  secure the reservoir  17  inside the housing  11 . See  FIG. 5 . 
         [0022]    A line guard  33  may be attached to, but is preferably integral with, the housing  11 . The line guard  33  is sized so that the top rim  19  of the reservoir  17  fits tightly inside the line guard  33  when the reservoir  17  is retracted into the housing  11 . The line guard  33  may be flush with the top rim  19 , or a small space may be left between the parts. The space between the line guard  33  and the top rim  19  is small enough to prevent trimmer line on the arbor  18  from being caught in the space above the top rim  19  when the head is in the use or advance position, described below. 
         [0023]    The head  10  attaches to the main shaft  30  of the vegetation trimmer, which in turn is attached to a motor that drives rotation of the main shaft  30  and the head  10 . The head  10  may be attached to the main shaft  30  using methods known in the art. Preferably, the main shaft  30  has a nut  31  that fits into a hex-shaped recess in the top of the housing  11 . The main shaft  30  extends through the shaft  13 , where a locking screw  32  having a head that is wider than the inner diameter of the shaft  13  screws into the end of the main shaft  30 . When the locking screw  32  is tightened, the locking screw  32  and the nut  31  hold the head  10  in place on the main shaft  30 . The main shaft  30 , housing  11 , spring  27 , and reservoir are all substantially coaxial. If the base  22  is removable, it may be attached to the bottom of the reservoir  17  after the locking screw  32  is screwed into place. 
         [0024]    The positions of the preferred head  10  are illustrated for a vegetation trimmer with a main shaft  30  that is rotated clockwise, from the bottom view, by the motor in order to cut vegetation. Referring to  FIG. 3 , from the use position, turning the reservoir  17  counter-clockwise releases the mate of the positioning pegs  23  and the notches  16 . The spring  27  then pushes the reservoir  17  out of the housing  11  until the flanges  14 ,  21  contact each other. This fully extended position is the load position. The reservoir  17  may be freely rotated by the user&#39;s fingers, and the user can wind trimmer line onto the arbor easily, ensuring proper winding by visual inspection and manipulation by fingers. Starting from an empty reservoir  17 , the user loops the trimmer line around the hook  25  and turns the reservoir  17  clockwise to wind the trimmer line onto the arbor. When fully wound, the two line ends are fed through the line openings  15  and the reservoir  17  is pushed into the housing and turned clockwise to lock it into the use position. It is contemplated that these rotational directions may be reversed, depending on the needs of the design. 
         [0025]      FIG. 5  shows the preferred embodiment of the head  10  in the use position. The positioning pegs  23  are mated with the notches  16  and locked against the rotational direction of the head  10  when the vegetation trimmer is in use; that is, the design of the positioning pegs  23  and notches  16  prevent rotation of the reservoir  17  with respect to the main shaft  30  while the motor is operating. From the use position, the head  10  is placed in the advance position by pushing the reservoir  17  further into the housing  11 , releasing the lock of positioning pegs  23  against the notches  16 , and turning the reservoir  17  clockwise. Turning the reservoir  17  counter-clockwise from the use position causes the positioning pegs  23  to unlock and the reservoir  17  to drop down into the load position. 
         [0026]    While there has been illustrated and described what is at present considered to be the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made and equivalents may be substituted for elements thereof without departing from the true scope of the invention. Therefore, it is intended that this invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.