with reference to fig1 - 6 , the preferred embodiment of edging strip 10 of the present invention is shown . edging strip 10 is adapted for forced insertion into the ground to create borders around gardens , flower beds , trees and the like . edging strip 10 comprises flexible strip 14 which is preferably made of a high density polyethylene or polypropylene . flexible strip 14 has a height defined between top edge 18 and bottom edge 20 , a length defined from first end 24 to second end 26 , and a thickness defined between first face 30 and second face 32 . bottom edge 20 is preferably of a variable contour comprising a series of arches 36 and corresponding apexes 38 . apexes 38 facilitate initial positioning and insertion of bottom edge 20 into the ground . furthermore , the thickness of strip 14 has taper 15 at bottom edge 20 to further facilitate insertion of bottom edge 20 into the ground . bottom edge 20 may have any alternative contour that allows for insertion of bottom edge 20 into the ground . for example , fig7 shows bottom edge 20 &# 39 ; contoured in a sawtooth pattern to define a series of apexes 38 &# 39 ; and corresponding v - notches 37 . fig8 shows bottom edge 20 &# 34 ; contoured in a series of alternating half arches 39 and apexes 38 &# 34 ;. top edge 18 comprises flange 42 extending perpendicular to strip 14 such that top edge 18 has a t - shaped cross - section . flange 42 defines top surface 44 , first underside 46 , second underside 48 , first edge 50 , and second edge 52 . the configuration of flange 42 can be varied to achieve the desired aesthetics . in the preferred embodiment , top surface 44 is flat , first edge 50 is scalloped , and second edge is straight . scalloped edge 54 provides greater flexibility of top edge 18 to allow curving of strip 14 prior to insertion into the ground . top surface 44 is sufficiently wide to withstand hammering . it should be appreciated that any of a variety of top edge 18 configurations may be used . for example , fig9 and 10 show some alternative configurations of top edge 18 . fig9 shows top edge 18 &# 39 ; with an l - shaped cross - section . fig1 shows top edge 18 &# 34 ; with a more triangular cross - section . strip 14 further comprises first plurality of ribs 60 . first ribs 60 are spaced generally parallel to each other , extend from first face 30 of strip 14 , and are oriented generally perpendicular to the length of strip 14 . first ribs 60 are aligned with and taper toward apexes 38 . first ribs 60 have top end 62 joined with first underside 46 of flange 42 . first ribs 60 have first width 66 at top end 62 and a generally constant rate of taper from first width 66 to corresponding apex 38 . first ribs 60 also have edge 70 which has cutting portion 72 extending from a midpoint along edge 70 to apex 38 . cutting portion 72 is sharpened in a plane perpendicular to first face 30 and facilitates the insertion of strip 14 into the ground . first ribs 60 may be of any length , profile and cross - section as long as they provide sufficient rigidity and allow insertion of strip 14 into the ground . the combination of the configuration of first ribs 60 and apexes 38 define a series of stake - like portions along strip 14 . driving of strip 14 into the ground can be achieved by hammering along top surface 44 of top edge 18 . the web - like support provided by first ribs 60 between flange 42 and strip 14 provides sufficient rigidity in a vertical direction to allow hammering of strip 14 into the ground while at the same time , scalloped edge 54 of first edge 50 and the thickness of strip 14 allow for flexibility in the horizontal direction to allow curving of the strip . the preferred embodiment of strip 14 also comprises a second plurality of ribs 80 . second ribs 80 extend from second face 32 , are spaced generally parallel to each other and are aligned with apexes 38 . second ribs 80 have a top end 82 with width 84 at a midpoint on second face 32 that tapers to corresponding apex 38 . second ribs 80 further contribute to the creation of stake - like portions along strip 14 . second ribs 80 also have sharpened edges 81 to facilitate insertion of strip 14 into the ground . it is preferred that second ribs 80 not extend completely to top edge 18 so that smooth surface zone 86 is present along the top of second face 32 . smooth surface zone 86 provides the needed smooth surface for proper flexible line trimming of grass that is along and against second face 32 of strip 14 . additionally , smooth surface zone 86 provides for a neat , aesthetic appearance . alternatively , second ribs 80 may be of any length , profile and cross - section as long as they do not impede insertion of strip 14 into the ground . fig1 - 13 illustrate alternative embodiments for the first ribs and the second ribs . in fig1 , first rib 60 &# 39 ; and second rib 80 &# 39 ; have curved profiles with sharpened edges . additionally , first rib 80 &# 39 ; has cut - out 87 which is dimensioned to receive drip irrigation tubing or electrical wiring . with cut - out 87 on one or more first ribs 60 per strip 14 , tubing or wiring can be easily routed along the edging strip and concealed out of the way . in fig1 , first rib 60 &# 34 ; and second rib 80 &# 34 ; have rectilinear profiles with sharpened edges 88 to facilitate insertion of the ribs into the ground . fig1 illustrates an alternative embodiment of a first rib . first rib 60 &# 34 ;&# 39 ; is of a three - dimensional half - cone structure which provides mass and rigidity to facilitate driving of strip 14 into the ground . these figures illustrate the vast variety of configurations that the ribs can have . strip 14 also comprises a plurality of top support ribs 90 extending from first face 30 and first underside 46 . top support ribs 90 provide vertical rigidity to prevent strip 14 from bowing during hammering . top support ribs 90 are spaced between first ribs 60 . the present invention has up to now been described with reference to a single strip 14 . however , the present invention further comprises connections at each end such that several strips 14 can be connected to each other to create a lawn edging strip as long as desired and in any shape as desired . first end 24 of strip 14 comprises tongue 98 and second end 26 comprises groove 100 such that the tongue of the first end of one strip can be inserted , from the top , into the groove of the second end of another strip to connect the two strips together . by being able to insert tongue 98 vertically down into groove 100 , the strips of the present invention can be readily inserted into the ground one by one . specifically , once a first strip is hammered into the ground , the second strip can be positioned so that its tongue is directly over the groove of the first strip and then hammered directly into the ground . if the connection between the strips could only be achieved by a lateral entry , strip by strip installation would be cumbersome . tongue 98 further comprises protrusion 102 which interlocks with notch 104 in groove 100 . groove 100 is defined between flap 106 and first face 30 at second end 26 . flap 106 is attached to strip 14 along at least its bottom edge 108 . notch 104 is created in flap 106 . flap 106 is flexible to allow passage of protrusion 102 between flap 106 and first face 30 until protrusion 102 engages with notch 104 . second end 26 has flange 42 extending over flap 106 so that the connection is aesthetically concealed to give the appearance of a continuous lawn edge . the extended portion of flange 42 also prevents tongue 98 from raising up once tongue 98 is pressed into groove 100 . it should be appreciated that a variety of configuration of connecting structures can be used in the present invention as long as the connection does not interfere with the insertion of a series of strips 14 into the ground and preferably allows connection in a vertical direction . the present invention further comprises first vertical living hinge 114 spaced from first end 24 and second vertical living hinge 116 spaced from second end 26 . hinges 114 and 116 extend from top edge 18 to bottom edge 20 . flange 42 defines cut - outs 118a and b at hinges 114 and 116 , respectively , to allow freedom of movement of hinges 114 and 116 in one direction , and cut - outs 119a and b on the opposite side of cut - outs 118a and b , respectively , to allow freedom of movement of hinges 114 and 116 in the other direction . hinges 114 and 116 and cut - outs 118a and b and 119a and b allow first end 24 and second end 26 to be turned in either direction with respect to strip 14 . such turns provide for great versatility in the layout of the lawn edging strip including the ability to create sharp corners . almost any desired corner can be achieved by turning an end of the strip and then connecting another strip 14 to the turned end . with reference to fig1 the versatility of the present invention is further illustrated . strip 14 may be cut by a cutting implement 127 any distance from tongue 98 in such a way to shorten the length of strip 14 and create shortened strip 14a with second tongue 126 . additionally , when strip 14 is cut in such a way , one of the top support ribs 90 becomes second protrusion 128 on shortened rib 14a . the new tongue 126 and protrusion 128 structure can then be inserted into groove 100 of another strip 14 and engage notch 104 . fig1 illustrates a shortened strip 14a on the right being connected to the full strip 14 on the left . the full strip is already in position and tongue 126 of the shortened strip is positioned over groove 100 of the full strip . protrusion 128 is aligned with notch 104 and then the shortened strip can be hammered downwardly until the top edges of the strips are in alignment , protrusion 128 is engaged with notch 104 , and tongue 126 is locked underneath the top edge of the full strip . fig1 illustrates an example of a lawn edging layout including a right angle , curved strips , shortened strips and a tree ring . this layout takes advantage of the versatile features of living hinges 114 and 116 , the ability of the strip to be shortened while still capable of being connected to another strip and the overall flexibility of the strip along its entire length . fig1 and 18 illustrate an alternative embodiment of the present invention comprising separate extension pieces 130 which have a top end with crossed grooves 132 which are dimensioned to receive the cross - shaped cross - section of the stake - like portion of strip 14 defined by apex 38 , first rib 60 and second rib 80 . fig1 and 20 illustrate a further embodiment comprising separate stakes 136 which have top end 138 with slot 140 that is dimensioned to receive a top support rib 90 such that top end 138 will abut underneath first underside 46 of flange 42 of top edge 18 . stakes 136 can also be used on second face 32 of strip 14 to facilitate curving of strip 14 such that second face 32 is on the outside of the curve . in this situation , slots 140 of stakes 136 can be positioned over a second rib 80 near an end of the strip to firmly engage strip 14 and maintain the curve . preferably , stakes 136 are plastic stakes with a rib for support . however , because stakes 136 should be underneath top edge 18 if used with a top support rib 90 or below ground level with a second rib 80 , the stakes can be made from stamped metal and not pose a safety risk . the further embodiments of fig1 - 20 are useful when the area in which the edging is to be used has loose material such as mulch or peat moss that will not hold a curve of a strip 14 . extension pieces 130 and / or stakes 136 can then be used to reach firmer ground beneath the loose material so a curve of the strip can be maintained . to install the lawn edging of the present invention , the desired layout of the edging should first be planned so it can be determined if any strips will need to be shortened to make up the desired layout . the second face with the smooth surface zone 86 should face the grass . the first strip inserted should be the strip that will not need a connection to its tongue end . then , the strips can be connected and inserted one at a time by connecting the tongue of the next strip into the groove of the previously inserted strip until the layout is complete . for each strip , the top surface of the flange of the top edge is hammered along its length to work the lawn edging into the ground . although the present invention has been described with respect to a preferred embodiment , various changes , substitutions and modifications of this invention may be suggested to one skilled in the art , and it is intended that the present invention encompass such changes , substitutions and modifications as fall within the scope of the appended claims .
a lawn edging device is provided in the form of a strip having a top edge configured for withstanding hammering , a bottom edge configured for penetration into the ground , and ends constructed for interlocking with adjacent strips . a plurality of ribs spaced parallel to each other extend from both sides of the strip and are oriented perpendicular to the length of the strip to provide vertical rigidity to the strip . the ribs taper towards the bottom edge of the strip and facilitate the penetration of the strip into the ground .