Abstract:
A substantially toroidal container for coiled vegetation trimmer line has a front shell and a rear shell capable of bonding at the center with heat and pressure, radio frequency, ultrasonic welding, adhesive, or attachment mechanisms. The bonding of the shells leaves a separation between the outer edges of the shells. The separation is nonlinear around the circumference of the container, so that a user can access the trimmer line, but the trimmer line cannot uncoil and spill out of the container. The separation is preferably defined by a series of offset uniform teeth on the outer edges of the shells. One or more teeth may be removed, providing a line aperture through which the end of the trimmer line extends out of the container. Male and female indices on each shell are used to align the teeth during packaging.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation and claims the benefit of U.S. patent application Ser. No. 12/768,552, filed Apr. 27, 2010. 
     
    
     FIELD OF INVENTION 
       [0002]    This invention relates to vegetation trimmer line. This invention relates particularly to an apparatus and method for packaging vegetation trimmer line. 
       BACKGROUND 
       [0003]    Vegetation trimmers using flexible trimmer lines are in widespread use. Generally, the trimmer line that is used in rotating string trimmers is manufactured or extruded of nylon materials. The trimmer lines may have various cross-sectional shapes, such as round, oval, square, and multi-lobal. The cross-sectional diameters of the line used in the trimmers vary from larger cross-sectional diameters for commercial trimmers to smaller diameters in the trimmers sold for home use. The diameter at its largest point is generally in the range of 0.050 to 0.170 inches. 
         [0004]    Certain types of vegetation trimmers have trimmer line wound and stored on a reel or spool that fits in the housing of the head of the device. The line is played out from the reel in discrete amounts as the line breaks off or wears down. When the supply of line on the storage reel is used up, additional line is provided from a continuous length of replacement line supplied in a trimmer line package. The amount of line that is provided in such packages typically is equal to the amount of line wound on a storage reel, or it is in excess of the amount of line which can be wound on a reel, thereby providing more than one reel&#39;s worth of line replacement. 
         [0005]    One way of packaging replacement line is to coil the desired length into a toroidal container, known as a donut. Some donut containers are completely sealed and must be opened to take out any line. Another type of donut container is split into two halves that interface with each other around the outer circumference of the container. At the periphery of the container, the halves may abut each other or be separated by a small gap. In either case, the abutment or gap is planar or linear and allows trimmer line to be pulled out of the container. However, trimmer line is resistant to coiling, and the coils expand if they are unbound. In the known split-donut container, when the line begins to uncoil, such as during shipping of the package, the expanding coils easily push their way through the abutment or gap and out of the container. The line must then be rewound into the container upon arrival at a retail facility, or, worse, the line is not rewound and the container is put on the shelf with the trimmer line sticking out of it. A donut container that can contain unbound trimmer line while providing easy access to the line is needed. 
         [0006]    Another problem arises during shipping when many donut containers are packed together. It is common for the containers to rub against each other when they are jostled, scratching the facing surfaces of the containers. Depending on the material used for the packages, the damage caused can be so severe as to render opaque an otherwise transparent package. A donut container that limits or prevents this kind of damage is needed. 
         [0007]    Therefore, it is an object of this invention to provide a container for coiled trimmer line that retains the line in the package but allows easy access to the line. It is a further object that the container be toroidal. Another object of this invention is to provide a trimmer line container that is an improvement over existing donut-shaped containers. A further object is to provide a container that limits surface damage from other containers during shipment. Another object is to provide a method for packaging trimmer line in a toroidal package. 
       SUMMARY OF THE INVENTION 
       [0008]    A container for coiled vegetation trimmer line has a front shell and a rear shell that have substantially the same periphery. Each shell is plastic and has a bonding surface on which a bond between the shells is formed using heat and pressure, radio frequency, or ultrasonic welding. Once bonded together, the outer edges of the shells may abut each other or be separated by a small gap around the circumference of the container, so that a user can access the trimmer line. A series of offset teeth are formed on the outer edges of the shells to prevent the trimmer line from uncoiling and spilling out of the container. The teeth may be squared or curved, but are preferably curved. One or more teeth may be removed to form a line aperture that allows one end of the trimmer line to extend out of the container without spreading the teeth apart. One or more index modules comprising male and female indexes are used to align the teeth during packaging. One or more spacers may be positioned on the front shell, back shell, or both shells, in order to separate the container from other containers in a shipping box. To package the trimmer line in the container, the rear shell is placed in a bonding machine. A bound coil of trimmer line is placed in the rear shell. The front shell is lowered onto the rear shell and rotated until the male and female indexes align. The shells are bonded at their respective bonding surface, and the coil is unbound. Alternatively, the shells may be bonded with the container empty, and trimmer line may be inserted into the container, coiling around the center. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an exploded perspective view of the preferred embodiment of the present invention, showing the front and rear shells. 
           [0010]      FIG. 2  is a perspective view of the container of  FIG. 1  having abutting outer edges and a wavy ring spacer. 
           [0011]      FIG. 3A  is a perspective view of a container with a ring spacer on the front shell. 
           [0012]      FIG. 3B  is a perspective view of a container with node spacers on the front shell. 
           [0013]      FIG. 4  is a front view of a container without a spacer. 
           [0014]      FIG. 5  is a right-side view of a container with non-abutting outer edges. 
           [0015]      FIG. 6A  is a side view showing one embodiment of a spacing between non-abutting outer edges in profile. 
           [0016]      FIG. 6B  is a side view of an alternative embodiment of  FIG. 6A , showing an interlocking outer edge with squared teeth. 
           [0017]      FIG. 6C  is a side view of another alternative embodiment of  FIG. 6A , showing a zigzagged outer edge with triangular teeth. 
           [0018]      FIG. 6D  is a side view of another alternative embodiment of  FIG. 6A , showing a scalloped outer edge. 
           [0019]      FIG. 7  is a right-side perspective cross-section of the container of  FIG. 4 , taken along line  7 - 7  of  FIG. 4 . 
           [0020]      FIG. 8  is a flow diagram of a method for making the preferred container. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring to  FIGS. 1 and 2 , there is illustrated the preferred embodiment of the present invention, designated generally as  10 , which is a container for a coil of replacement trimmer line. The container  10  preferably has a substantially toroidal shape with a cross-sectional shape  60  that is rotated around a central axis A-A. See  FIG. 1  and  FIG. 7 . The cross-sectional shape  60  may be any shape capable of retaining the coiled trimmer line within the container  10 , such as a square, diamond, rectangle, trapezoid, other polygon, circle, oval, ovoid, ellipse, or other rounded shape. Preferably, the cross-sectional shape  60  is a rectangle having semicircular ends of equal radius. The volume inside the cross-sectional shape  60  rotated  360  degrees around the axis A-A defines the space for storing the trimmer line. Alternatively, the container  10  may be another shape, such as circular or square. 
         [0022]    The container  10  may be divided into a front shell  11  and a rear shell  12 , which are preferably separately manufactured. Each shell  11 ,  12  preferably comprises about half of the toroid, although in alternative embodiments the front shell  11  or rear shell  12  may be different sizes or shapes. For example, the rear shell  12  may be flat, resulting in a half-toroid container  10 . In another example, one shell may be substantially larger than its counterpart. The shells  11 ,  12  are made of plastic, preferably one or more thermoplastic polymers such as polyethylene terephthlate (“PET”) and polyvinyl chloride (“PVC”). The shells  11 ,  12  may have the same or different degrees of flexibility and resiliency. Preferably, the shells  11 ,  12  are sufficiently flexible to allow a user to reach into the container  10  and pull out an end of the trimmer line, returning to their original shape after the line is removed. 
         [0023]    The front shell  11  and rear shell  12  each have an outer edge. In the preferred embodiment, the front and rear outer edges are substantially on the outer circumference of the toroid. The interface of the front outer edge with the rear outer edge defines a separation  15  between the shells  11 ,  12 . In the preferred embodiment, the separation  15  has substantially no width, as the front outer edge abuts the rear outer edge. See  FIG. 2 . In alternative embodiments, the front outer edge may be disposed slightly apart from the rear outer edge, so that the separation  15  is a gap having a width W that may be wider or thinner than the trimmer line. See FIGS.  5  and  6 A-D. The width W may be uniform or nonuniform around the outer circumference of the container  10 . In any embodiment, the front shell  11 , rear shell  12 , or both, are sufficiently flexible and resilient to deform and allow trimmer line to be pulled through the separation  15 , subsequently reassuming their respective shapes. 
         [0024]    Referring to  FIGS. 1-3B , one or both of the front shell  11  and rear shell  12  may have one or more spacers  23  attached to or integral with the outer surface of the shell. A spacer  23  is designed to separate the container  10  from other articles, such as other containers or box walls, that might scratch the outer surface of the shell on which the spacer  23  is positioned. The spacer  23  may be any shape and height that protects the shell, and is preferably flat or rounded on top so as not to damage articles that it contacts. For example, the preferred spacer  23  is a wavy ring shown in  FIGS. 1 and 2 , which emulates the shape of the preferred outer edges of the shells  11 ,  12 .  FIG. 3A  illustrates a ring spacer  23  and  FIG. 3B  illustrates a series of three node spacers  23  on the front shell  11 . 
         [0025]    The front and rear outer edges are formed into cooperating shapes around the outer circumference, so that the separation  15  is not a straight line. The cooperating shapes on the outer edges may be uniformly or nonuniformly repeated around the outer circumference, and may be uniform or nonuniform in size, so long as the front outer edge interfaces with the rear outer edge to maintain a nonlinear or nonplanar separation  15 . As shown in  FIG. 2 , the preferred container  10  may be considered to have “ribbed” outer edges with rounded teeth  16  protruding from one shell into the space between adjacent rounded teeth  16  on the opposite shell. See also  FIG. 6A . In the preferred embodiment, the rounded teeth  16  have uniform size and spacing, creating an undulating separation  15  around the container  10 .  FIGS. 6B-D  illustrate alternative embodiments, which may be implemented with abutting or non-abutting outer edges. The embodiment of  FIG. 6B  has interlocking squared teeth  51  on the outer edges.  FIG. 6C  illustrates a “zigzagged” separation  15  formed by alternating triangular teeth  52 .  FIG. 6D  illustrates “scalloped” edges, with the front outer edge formed into round teeth  53  and the rear outer edge having cooperating peaks  54 . The present invention contemplates any combination of cooperating shapes forming a separation  15  that is sufficiently nonlinear to prevent the contained trimmer line from sliding or bursting out of the separation  15  as it naturally uncoils inside the container  10 . 
         [0026]    One or more of the cooperating shapes on one or both of the front shell  11  or rear shell  12  may be omitted from the cooperating pattern in order to provide a line aperture  17  on the outer circumference. The aperture  17  allows easier access into the container  10  than is provided by the separation  15 . Additionally, the “loose” end of the trimmer line in the container  10  may extend out of the container  10  through the line aperture  17  to be retained outside the container  10  as described below. This keeps the trimmer line from widening the separation  15  at the point where it extends out of the container  10 . Preferably, a single rounded tooth  16  is omitted from the rear outer edge near the top of the container  10  to create the line aperture  17 . See  FIG. 5 . Structural support may be provided by a lip  18  and rim  19  molded integrally with each of the front shell  11  and back shell  12 . The lips  18  are attached to each of the front and rear outer edges, extending substantially horizontally out from the outer edges, then extending substantially parallel to the container&#39;s  10  axis A-A, shown in  FIG. 1 , to a depth L shown in  FIG. 5 . The parts of the lips  18  that extend out from the outer edges may contact each other in embodiments having abutting outer edges. See  FIG. 7 , showing abutting lips  18  and the attached rims  19  in cross-sectional profile. The depth L is preferably slightly greater than the depth D of the rounded tooth  16 . See  FIG. 5 . A rim  19  connected to each lip  18  extends horizontally outward from the lip  18 , for preferably about 0.125 inches. A hang tab  27  for hanging the container  10  on a retail rack may be integral with the rim  19  on the front or rear shell  11 ,  12 , preferably the rear shell  12 . The hang tab  27  may have a set of line retention holes  28  through which the loose end of the trimmer line is passed to hold it, by friction, outside the container  10 . 
         [0027]    The front shell  11  has a front bonding surface  13  attached to or integral with the inner edge of the front shell  11 , and the rear shell  12  has a rear bonding surface  14  attached to the inner edge of the rear shell  12 . The bonding surfaces  13 ,  14  are aligned and subjected to a bonding process to attach the front shell  11  to the rear shell  12 , forming the container  10 . Preferably, the bonding surfaces  13 ,  14  are circular plastic discs that are integral with the shells  11 ,  12  and have a diameter equal to the inner diameter of the toroid. Alternatively, the bonding surfaces  13 ,  14  may be annular discs having enough surface area to ensure formation of a solid bond between the bonding surfaces  13 ,  14 . The shells  11 ,  12  may be aligned, offsetting the teeth  16  to form the desired separation  15 , using one or more indexing modules. The indexing modules are paired as a male index  25  and a female index  26  formed into the bonding surfaces  13 ,  14 . The male and female indexes  25 ,  26  are the same size and shape, with the female index  26  being the inverse of the male index  25 . The indexes  25 ,  26  may be any shape, such as triangular or quadrilateral pyramids, prisms, or cubes, and placed in any configuration that allows reliable indexing of the shells  11 ,  12 . In one embodiment, a single pair of pyramid-shaped indexes  25 ,  26  may be used, the indexes  25 ,  26  having a regular or irregular polygonal base. For a regular polygon, the number of sides corresponds to the number of aligned positions in which the front shell  11  may be placed. For example, if a square base is used, the shells  11 ,  12  will align at 90 degree increments. Preferably, the front bonding surface  13  has two cylindrical male indexes  25  that project rearward, matching and aligning with cylindrical female indexes  26  on the rear bonding surface  14  that also project rearward. 
         [0028]      FIG. 8  illustrates a process of manufacturing the preferred container  10 . The front and rear shells  11 ,  12  are separately formed  71 , preferably by thermoforming sheets of the shell material. The desired amount of the desired trimmer line, having been previously or contemporaneously coiled and bound with a removable or temporary binding, is placed  72  in one of the shells  11 ,  12 , preferably the rear shell  12 . The shells  11 ,  12  are aligned  73  using the indexing modules  25 ,  26  and the bonding surfaces  13 ,  14  are brought into conforming contact. The container  10  is then positioned  74  in a bonding machine, which uses any technique for bonding thermoplastics, such as heat, pressure, radio waves, ultrasonic welding, or a combination of these. The bonding machine bonds  75  the front shell  11  to the rear shell  12  by melting parts of one or both bonding surfaces  13 ,  14 . Finally, the binding on the coil of trimmer line is removed  76 . Depending on the size and length of the trimmer line, the binding on the coil may be removed  76  earlier in the process if the trimmer line will remain substantially coiled without the restraining binding in place. 
         [0029]    Alternative methods of manufacturing the container  10  are contemplated. The shells  11 ,  12  may be made by injection molding or another process used in plastics manufacturing, rather than thermoforming. In place of a melt bond, the front shell  11  may be attached to the rear shell  12  by an adhesive or an attachment mechanism such as staples, rivets, or mating tabs formed into the shells  11 ,  12 . The front shell  11  may be attached to the rear shell  12  before the trimmer line is coiled and placed  72  in the container  10 , or the front and rear shells  11 ,  12  may be integrally cast as a single piece. The empty finished container  10  may be placed in a feeding machine that feeds trimmer line so that it coils inside the container  10  while being fed into it. The trimmer line is then cut when the container  10  is full. 
         [0030]    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.