Patent Publication Number: US-2007113473-A1

Title: Circular retaining device for landscaping

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates to a device placed on the around around the base of an object, such as a tree or shrub, for retaining decorative landscaping materials.  
      Landscape apparatus of many types and configurations have been utilized around the base of trees and shrubs to suppress undesirable overgrowth on the ground surface. (See U.S. Pat. No. 5,794,378). Such devices also protect the object they are placed around from being damaged by overgrowth trimming equipment, such as lawnmowers and weed-eaters. Several such apparatus also incorporate a means for retaining landscaping materials, such as mulch or decorative rock, around the base of the object. U.S. Pat. No. 5,711,106, for example, provides an inverted V-shaped wall for retaining landscaping materials. The majority of such devices are circular in shape and have a vertical circular side wall of a few inches in height.  
      The prior art landscape retaining/edging products are generally manufactured from plastic that its molded to conform to the inventor&#39;s preferred shape. Significant economic advantage can be obtained by limiting the assembly labor in addition to having the greatest amount of flexibility with regard to variety of ground conditions, tree/shrub base diameters, and landscape fillers to be used, all at a reasonable cost. Of the devices presently known in the art, manufacturing typically requires the high cost of developing molds from which the product can fabricated by injection of molten plastics (“injection molding” process). The high cost of injection molding (mold manufacturing, plastic melting, etc.) however typically results in a prohibitive cost to the consumer and poor economy to the inventor and manufacturer. What is needed in the art is a landscape edging device that can provide the strength and durability of an injection molded device, but be cut directly from plastic sheets using low-cost die pressing. The inventors present a device designed to be fabricated from a plurality of sub-components cut from flat material sheeting and held together with conventional fasteners. This design allows the landscape edging device to be fabricated in various sizes and from various different materials, colors and textures. Additional novel features are incorporated that provide critical strength to withstand heavy, coarse landscape materials and the harsh outdoor environment. The inventors also incorporate in the device a means for collecting and distributing water to the area around the retaking ring, which promotes lateral root growth for trees and shrubs. 
    
    
     DESCRIPTION OF THE DRAWINGS  
       FIG. 1  presents a three-dimensional side view of the assembled circular retaining device for landscaping of the present device.  
       FIG. 2  presents a top view of the base plate of the present invention to show the various slits in the base plate for receiving the edging pieces.  
       FIG. 3  presents a side view of an edging piece comprising the side wall of the present device.  
       FIG. 4  presents a cross-sectional side view of the edging piece inserted into the base plate with the bottom of the tab of the edging piece bent into place and with the securing insert pushed into place.  
       FIG. 5  presents an enlarged view of one end of the edging piece shown in  FIG. 4 . to show features of the locking tabs. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      Referring to the drawings,  FIGS. 1 through 4 , where numerals represent corresponding parts for all drawings,  FIG. 1  shows one embodiment of the device. This drawing shows a thin, flexible circular base  10  with a central circular aperture  16  to receive the base of a tree, shrub or other object. A slit  12  in the circular base  10  runs radially from the edge of the central aperture  16  to the outer edge of the circular base. This slit provides a means for allowing the circular base to be placed around the tree, shrub or object. A side wall  30  is shown attached to the circular base  30  forming a circle around the periphery of the circular base. In one embodiment, the side wall  30  is formed from two flexible strips of materials that are secured together by overlapping the ends and insertion of a suitable fastener through a plurality of holes  40  However, for smaller circular base diameters, a single side wall strip may be used.  FIG. 1  also shows a plurality of perforated rings  20  extending outwardly from the central circular aperture that assist the user in enlarging the central circular aperture to accommodate larger base diameters of the object the present invention is placed around. The circumference created by the side wall  30  is slightly less than the overall outer diameter of the circular base  10  to create an outer lip  22 . This outer lip  22  prevents the growth of ground flora directly adjacent to the side wall and aids in trimming the flora without adversely impact the side wall. The outer lip  22  is also formed as a result of locating the side wall attachment points  32  (See  FIG. 2 .) in from the outer edge of the circular base  10  to increase the strength of the side wall retention means.  
       FIG. 2  shows a plan view of the circular base  10  without the side walls. This view shows a plurality of attachment points  32  placed along a circular pattern of diameter slightly less than the outer diameter of the circular base  10 . These attachment points are comprised of a short slit  33  into the circular base  10  running tangential to diameter of said circular pattern. A shorter slit  34  is cut into the circular base that starts at the mid-point of the tangential slits  33  and runs radially inward towards the center of the circular base  10  at a distance approximately ½ of the width of the tangential slit  33 . The purpose of this radial slit is to aid in separation of the tangential slit when the side wall securing tabs  36  are inserted. The tangential and radial slits receive the plurality of securing tabs  36  which extend below the bottom edge of the side wall  30  (See  FIGS. 3 and 4 ).  
       FIG. 2  also shows the slit  12 , which runs from the center of the circular base  10  extending radially outward to the outer edge. To provide structural strength to the circular base  10  after it is placed around the base of object being protected by the present invention, a fastening strip  40  is placed under the circular base  10  and centered along the radial slit  12 . The fastening strip  40  includes a plurality of holes  42  which have matching holes in the circular base. A suitable fastener is inserted into the hole on the circular base and extends through the corresponding hole in the fastening strip  40 . The fasteners and fastening strip may be removed to allow the user to resize the central aperture for adapting the device to trees, shrub or objects of varying base diameter.  
       FIG. 3  shows a side view of the side wall  30  separated from the circular base  10 . A plurality of securing tabs  36  extends below the bottom edge of the side wall  30 . The number of securing tabs matches the number of tangential  33  and radial slits  34  in the circular base  10 . Each securing tab is comprised of a pointed bottom edge  52  and a pair of rounded notches  56  located on either side of the securing tab  36  at the bottom edge of the side wall  30 . An arc-shaped slit  38  is cut into the top section of the securing tab  36  that aids in retaining the side wall to the circular base  10 . The width d if the securing tab is measured as furthest linear extent across the securing tab, which is from the upper point of the rounded notch  56 , across the width of the securing tab, to the upper point of the rounded notch on the other side of the securing tab. The width d of the securing tab is made just slightly larger than the length of the tangential slit  33  in the circular base  10 . When the two upper points pass through the tangential slit  33 , the slit slightly stretches then returns to lock circular base into the pair of rounded notches  52 . The bottom edge of the side also contains a plurality of semi-circular shaped notches or holes  50  where water can flow out of the central space. These holes direct water to the outer rim of the present invention, which promotes lateral root growth and prevents water from collecting and standing inside the side wall area.  
      In one embodiment, the side wall is formed from a single piece of flexible material, such as a thermoplastic sheeting, and joined on the ends by an attachment means, such as a plastic rivet fastener, to form a circle around the periphery of the circular base  10 . In another embodiment, the side wall  30  is formed from two pieces of flexible material, each foiling a half-circle, aid joined on the ends by an attachment means to form a continuous side wall around the periphery of the circular base  10 .  
       FIG. 4  shows a cross-sectional view of the side wall  30  inserted into the circular base  10 . One of the plurality of securing tabs  36  is shown inserted through the tangential  33  and radial  34  slits in the circular base  10 . Once through the circular base, each securing tab  36  is bent in a direction either toward or away from the axis of the circular base  10 . When the securing tab  36  is bent, the arc-shaped slit  38  allows a piece of the securing tab material to protrude and create a retaining flap  39  that extends out at an angle different from the angle formed by the side wall  30  and the rest of the securing tabs  36 .  
      The retention of the side wall to the circular base  10  is greatly strengthened by three specific means: 1) contact between the upper points of the rounded notches  56  in the securing tabs against the underside surface of the circular base  10 , 2) contact between the securing tab  56  body and the underside of the circular base  10  after bending the securing tab to some angle, and 3) contact between the retaining flap  39  and the underside of the circular base  10 . Also, after bending the securing tabs under the circular base, the pointed edges aid in securing the whole assembly to the ground of other surface by contacting the ground.  
      Except for the fastening means, the present invention can generally be fabricated from cutting flat thin sheets of material using a die press. In one embodiment, a durable thermoplastic material, such as high-density polyethylene with ultra-violet light stabilizers, is used. However, any durable, flexible and cuttable material could alternatively be used. A decorative molded trim could also be placed around the upper edge of the side wall  30  to improve the aesthetic appearance of the device. The circular base can be made to any overall diameter that is economically practical given the availability of starting sheet material. Typical dimensions include 24, 36 and 48 inches. The thickness of the circular base material and the side walls are minimized to reduce material cost. In one embodiment, the circular base is approximately 3/32 inch thick, which provides suitable strength but also enough flexibility to allow the base to conform to uneven and bumpy ground surfaces around the object. The side wall material thickness is also minimized to improve flexibility yet sufficiently thick to provide adequate strength to retain landscaping materials. In one embodiment, the side wall material thickness is approximately 1/32 of an inch. The side wall  30  can be of any height desired but is generally preferred to between 2 to 4 inches due to practical and aesthetic concerns.  
      While the above detailed description describes the present invention, it is understood that modifications, variations and alterations can be made without deviating from the scope and fair meaning of the subjoined claims.