Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation application of Application No. 61/861,425 filed on 2013 Aug. 1, a provisional application as identified in the accompanying Application Data Sheet. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO A SEQUENCE LISTING, A TABLE OR A COMPUTER PROGRAM LISTING COMPACT DISC INDEX 
     Not Applicable 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to weeding tools, specifically to pulling devices for use in uprooting plants from the soil by gripping the stems. 
     PRIOR ART 
     Open space restoration has become an activity of much interest due to increased awareness of disappearing wild lands and open spaces, and the degraded quality of many lands that have been designated as natural preserves. The lands are degraded because typical previous land uses, particularly farming and ranching, employed intensive transformation of the environment to support plants for direct human consumption and feeds for domesticated animals bred for human consumption or as materials for human manufactured products. 
     As such the native flora and fauna were regarded as useless clutter on the land and were destroyed wholesale in the transformation. A very undesirable consequence of the transformation was the introduction of various plant species, some intentionally, others unintentionally, from distant places that are in natural balance in their native environment but completely out of balance in the transformed environment. The imbalance is due to absence of bio-controls in the transformed environment that are naturally present in the native environment of the introduced species. In other words, nothing eats the introduced plants so they grow out of control and reproduce unchecked to form mono-cultures that exclude virtually all of the native species. The result is a completely out-of-balance ecosystem that desperately needs intervention to help restore the balance. 
     Examples of intentionally introduced species in North America are Fullers&#39; Teasel, formerly used for processing fibers such as wool for textile materials, and Poison Hemlock as an ornamental. An example of an unintentionally introduced species as contamination in a different seed stock for food plants is Yellow Starthistle. These plants spread rapidly in massive numbers and form dense mono-cultures that exclude all other species not only by their sheer numbers but also sometimes by chemical means with herbicidal substances emitted from their roots. 
     So it has become imperative to remove the invasive species before native plant restoration can be accomplished successfully. Many methods have been tried and are currently in use including mechanical, chemical and fire controls. Some have been successful and some have not. 
     The focus of this invention is on the mechanical means, particularly hand tools, of which there have been many varieties. Many of the previous hand tools were designed for similar purposes to that of this invention but not for use on as large of a scale. Most of them were not successful, as is readily evident by the proliferation of such devices in patent history, yet with the obvious absence in the market at the present time of all but the most simple generic brute force tools such as picks and shovels that are the commonly preferred choice. But the simple generic tools require a great amount of manual labor to operate and usually deliver high impact shock and stress to the operator&#39;s muscles and skeletal joints, resulting in damage to the physiology of the operator in both the short term and long term. 
     From analysis of why the more complex and specialized tools have failed to gain acceptance, a few general conclusions can be ascertained. The tools look plausible on paper and in concept, but they don&#39;t perform very well in reality, and in particular don&#39;t scale up well to the large volumes required for open space restoration. That is mainly because they all have one or more unfavorable characteristics that may seem insignificant at first, but prove to be fatal once they are put to the test in the real world. 
     One major detriment is excessive weight. Hauling large heavy tools around requires substantial operator strength and causes so much fatigue that even shortly after transport to the work site the operator doesn&#39;t have enough energy left to actually do a substantial amount of useful work. Then at the work site, substantial operator strength is required to operate the tool leading to rapid fatigue. 
     Another highly significant impediment is that many tools require too much maintenance such as removal of extracted plant material from their gripping mechanisms or manual re-opening of closed jaws by the operator after use on each plant, making it impossible to accomplish much in the available work time even when they do operate according to design. 
     One feature particularly pertinent to this invention is the use of opposing jaws to grip a plant by the stem. Opposing jaws, when both in rigidly attached positions, close together at a fixed relative angle parallel or otherwise to each other, but the plant stems that they are trying to grip have a natural vertical taper that varies from one plant to another and so is inevitably going to be different from the relative closure angle of the jaws most of the time. So the jaws are compelled to concentrate most of their gripping force along a narrow region within their surface area where they first contact the plant stem. That causes the plant stem to be pinched in the contact region, crushing and severing the stem instead of pulling the plant out of the ground. 
     All of the characteristics described above are not merely conjecture, but rather have been observed directly during development and testing of this invention. That strongly suggests most of the previous designs either performed inadequately or were impractical to use on a large scale such as for open space restoration projects. 
     The US patent classes found to be the most relevant in the search for previous inventions with similar characteristics to this invention are 172/371, 172/378, 254/132, 294/50.5, 294/50.8 and 294/50.9. 
     The following references are to previous patents that each exhibit at least one of the above mentioned characteristics. 
     
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
               
               
                 US Patent Number 
                 Date 
                 Inventor 
                 Class 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 332,169 
                 Dec. 08, 1885 
                 Stocking 
                  294/50.9 
               
               
                 779,984 
                 Jan. 10, 1905 
                 Allen 
                 254/132 
               
               
                 935,020 
                 Sep. 28, 1909 
                 Harvey 
                 254/132 
               
               
                 961,644 
                 Nov. 30, 1909 
                 Miller 
                  294/50.5 
               
               
                 4,856,759 
                 Aug. 15, 1989 
                 Ness 
                 254/132 
               
               
                 5,535,833 
                 Jul. 16, 1996 
                 Mathews 
                 172/371 
               
               
                 5,743,340 
                 Apr. 28, 1998 
                 Giacomini 
                 172/371 
               
               
                 6,938,937 
                 Sep. 06, 2005 
                 Kinney 
                  294/50.9 
               
               
                 7,063,168 
                 Jun. 20, 2006 
                 Paloheimo et al 
                 172/378 
               
               
                   
               
             
          
         
       
     
     SUMMARY OF THE INVENTION 
     The focus of the invention is an improved manually operated tool for weed removal that increases operator efficiency to better cope with the typical high volumes of invasive weeds that need to be dealt with in degraded open space restoration projects. It has been observed through extensive field testing that most weeds have sufficient stem-to-root bonding strength that they can be fully uprooted from the ground by gripping only the stem and with no ground penetration, provided that a firm enough grip can be achieved on the stem. To that end, this invention provides a greatly improved gripping means to take advantage of the weed structural strength characteristics. Combined with light weight components and self-retracting jaws that automatically release an uprooted weed, very rapid high volume weed removal can be accomplished. Additional benefits are greatly reduced operator fatigue and virtually no harmful physical stress, phenomena commonly associated with the large amount of energy expended and muscle and joint damaging shock routinely encountered with previous tools. Physical stress is particularly a concern for senior citizens, which I the inventor, as a senior citizen myself, am acutely aware of, having experienced first hand many of the troublesome effects of aging. For many senior citizens in retirement, participation in such open space restoration activities is highly desired but often severely restricted due to the extra stress imposed by conventional tools upon an aging physiology. 
     The invention accomplishes the goals with a leveraged pair of opposed jaws that firmly grip a weed stem by automatically conforming the jaw surfaces to the natural vertical taper that occurs in all weed stems. Additionally, textured surfaces on the jaws press into the deformable weed stem structural material to increase contact surface area and minimize slippage vertically along the stem. A long handle attached to the end of a lever arm provides leverage for amplified gripping and lifting forces. And a means for retracting the jaws simply by the operator releasing force on the handle allows the jaws to automatically release an uprooted weed. Light weight component materials make the invention easy to carry to a work site and reduce the energy needed to operate it for long periods of time. The combination of those features allows the operator to remain in a comfortable standing position nearly all of the time and to move from weed to weed very rapidly, in contrast to the discomfort and wasted time and energy of unfavorable positions including crouching, bending over, crawling along the ground on hands and knees, or constantly shifting between up and down postures. 
     An additional beneficial feature is that the components of the tool can be attached with standard removable nut and bolt hardware so that worn or damaged components are easily replaceable by the operator without having to acquire a complete new tool. Consequently the long term cost of ownership and maintenance of the tool is economically advantageous, and much less waste is generated, resulting in reduced negative environmental impact, consistent with open space restoration goals. Attention to these areas of concern are conspicuously absent in previous inventions. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a perspective right rear view of a tool according to the invention with jaws retracted and positioned around a weed stem. 
         FIG. 2  shows a perspective right rear view of a tool according to the invention with jaws closed and gripping a weed stem. 
         FIG. 3  shows a perspective right rear view of a tool according to the invention with jaws closed, gripping a weed stem and uprooting the weed. 
         FIG. 4  shows a detail view of the frame of such tool as in  FIG. 1 . 
         FIG. 5  shows a detail view of the lever arm assembly of such tool as in  FIG. 1 . 
         FIG. 6  shows a detail view of the tube component of the lever arm assembly of such tool as in  FIG. 5 . 
         FIG. 7  shows a detail side view of the left side lever arm component of the lever arm assembly of such tool as in  FIG. 5 . 
         FIG. 8  shows a detail side view of the right side lever arm component of the lever arm assembly of such tool as in  FIG. 5 . 
         FIG. 9  shows a detail view of the handle assembly of such tool as in  FIG. 1 . 
         FIG. 10  shows a detail view of the handle component of the handle assembly of such tool as in  FIG. 9 . 
         FIG. 11  shows a detail view of the handle adapter component of the handle assembly of such tool as in  FIG. 9 . 
         FIG. 12  shows a detail top right front perspective view of a jaw of such tool as in  FIG. 1 . 
         FIG. 13  shows a detail bottom right rear perspective view of a jaw of such tool as in  FIG. 1 . 
         FIG. 14  shows a detail view of the head of such tool as in  FIG. 1  with the jaws open and the retractor spring and spring retaining pin exposed. 
         FIG. 15  shows a detail view of the head of such tool as in  FIG. 2  with the jaws closed and with the retractor spring and spring retaining pin exposed. 
         FIG. 16  shows a detail view of the retractor spring of such tool as in  FIG. 14 . 
         FIG. 17  shows a detail view of the spring retaining pin of such tool as in  FIG. 14 . 
     
    
    
     LIST OF REFERENCE NUMERALS 
     
         
           1  frame 
           2  lever arm assembly 
           3  handle assembly 
           4  front jaw 
           5  rear jaw 
           6  retractor spring 
           7  spring retainer pin 
           8  pivot bolt and nut 
           10  frame front arm 
           11  frame top arm 
           12  frame rear arm 
           13  frame foot 
           14  frame pivot hub 
           15  frame pivot hole 
           16  frame front jaw upper mounting hole 
           17  frame front jaw lower mounting hole 
           18  frame spring upper mounting hole 
           19  frame spring lower mounting hole 
           20  lever arm tube 
           21  left lever arm 
           22  right lever arm 
           23  lever arm notch 
           24  lever arm handle upper mounting hole 
           25  lever arm handle lower mounting hole 
           26  lever arm pivot hole 
           27  lever arm rear jaw mounting hole 
           28  lever arm and handle upper mounting bolt and nut 
           29  lever arm and handle lower mounting bolt and nut 
           31  handle 
           32  handle adapter 
           33  handle grip cap 
           34  handle and handle adapter upper mounting hole 
           35  handle and handle adapter lower mounting hole 
           36  handle bottom end taper 
           37  handle upper mounting bolt and nut 
           38  handle lower mounting bolt and nut 
           40  jaw rear surface 
           41  jaw front surface 
           42  jaw right mounting rail 
           43  jaw left mounting rail 
           44  jaw right corner bracing 
           45  jaw left corner bracing 
           46  jaw upper mounting hole 
           47  jaw lower mounting hole 
           48  front jaw upper mounting bolt and nut 
           49  front jaw lower mounting bolt and nut 
           50  rear jaw mounting bolt and nut 
           61  spring torsion coil 
           62  spring front mounting coil 
           63  spring rear mounting hook 
           97  weed root 
           98  weed stem 
           99  earth 
       
    
     DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a perspective right rear view of a tool according to the invention. The tool in this embodiment comprises frame  1 , lever arm assembly  2 , handle assembly  3 , and jaws  4  and  5 . Wavy lines  99  below the tool represent the earth where the frame foot rests during operation and weed stem  98  represents a weed that the tool removes. 
     Frame  1  ( FIG. 4 ) is a rigid rectangular form comprising front arm  10 , top arm  11 , rear arm  12  and an open bottom, with foot  13  extending to the rear from the bottom of rear arm  12 . All of the arms are I-beam shaped along their cross-section with a side-to-side dimension of 15.75 mm. Of the side-to-side dimension the central body is 6.25 mm depth and the lips extend 4.75 mm outward from each side of the central body. The front-to-rear dimension for front arm  10  and rear arm  12  is 20 mm, and the top-to-bottom dimension for top arm  11  is 30 mm. The I-beam structure also extends continuously from rear arm  12  across the top of foot  13  with a dimension of 25 mm from the top of the structure to the bottom surface of foot  13 . Front arm  10  is 115 mm top-to-bottom, top arm  11  is 125 mm front-to-rear, and rear arm  12  is 130 mm top-to-bottom. The dimensions of foot  13  are 84 mm side-to-side, 100 mm front-to-rear and 6.25 mm top-to-bottom excluding the top I-beam structure. Pivot hub  15  protrudes symmetrically to the sides of the central body of top arm  11  along a circular profile of diameter 20 mm and outward 12.75 mm from each side for a total side-to-side dimension of 31.75 mm. The central axis of pivot hub  14  is positioned 35.5 mm forward from the rear edge and 15 mm up from the bottom edge of frame top arm  11 . Pivot hole  15  is 6 mm diameter through pivot hub  14  along the central axis. Front jaw mounting holes  16  and  17  are 6 mm diameter and centered 12 mm forward from the rear edge of frame front arm  10 . Hole  17  is centered 30 mm up from the bottom of frame front arm  10  and hole  16  is centered 20 mm up from the center of hole  17 . Spring hook mounting holes  18  and  19  are 2.5 mm diameter through the right side lip of frame rear arm  12  and are centered 3 mm inward from the outer edge of the lip. Hole  18  is centered 70 mm down from the top edge of top frame arm  11  and hole  19  is centered 6 mm down from hole  18 . 
     Lever arm assembly  2  ( FIG. 5 ) is comprised of tube  20 , left lever arm  21 , right lever arm  22 , handle upper bolt and nut  28  and handle lower bolt and nut  29 . Tube  20  ( FIG. 6 ) is a 95 mm length of 31.75 mm square 16 gauge mild steel square tube. Holes  24  and  25  are 6 mm diameter through two facing sides of tube  20 . Hole  24  center is 20 mm lengthwise from the top end of tube  20 , hole  25  is 50 mm below hole  25 , and both are centered along the width of tube  20 . Left lever arm  21  ( FIG. 7 ) is a 205 mm length of 31.75 mm by 31.75 mm by 6.25 mm aluminum angle extrusion with the face perpendicular to tube  20  trimmed to 20 mm width. Handle upper hole  24  is 20 mm lengthwise from the top end of lever arm  21 , handle lower hole  25  is 50 mm below handle upper hole  24  and pivot hole  26  is 50 mm below handle lower hole  25 . Holes  24 ,  25  and  26  are all 6 mm diameter and centered along the face of left lever arm  21  adjacent to tube  20 . Jaw hole  27  is 6 mm diameter and centered 6.25 mm from the bottom end of and 11 mm from the outer edge of left lever arm  21 . Corner notch  23  is cut from the bottom corner and inset 9.5 mm from the bottom edge and 6.25 mm from the outer edge of left lever arm  21 . The width of the face of left lever arm  21  adjacent to tube  20  matches the width of tube  20 , and holes  24  and  25  match the size and placement of the corresponding numbered holes in tube  20 . Right lever arm  22  ( FIG. 8 ) is a mirror image of left lever arm  21  with identical dimensions, the only difference being that the face perpendicular to tube  20  extends in the opposite direction from that of lever arm  21 . The lever arms are assembled on opposite sides of tube  20  and the assembly is secured together with handle assembly  3  by bolts and nuts  28  and  29  through holes  24  and  25 . 
     Handle assembly  3  ( FIG. 9 ) is comprised of handle  31 , handle adapter  32  and handle grip cap  33 . Handle  31  ( FIG. 10 ) is composed of round solid core fiberglass with dimensions 28.575 mm diameter and 1165 mm length. Handle grip cap  33  is inserted over the top end of handle  31  to provide a comfortable and firm grip for the operator. Tapered end  36  extends along the bottom 80 mm length of handle  31  at an angle of about 3.8 degrees relative to the normal exterior handle surface. Holes  34  and  35  in tapered end  36  are 6 mm in diameter and through the central axis of handle  31 . Hole  35  is 13 mm from the bottom end of handle  31  and hole  34  is 50 mm upward from hole  35 . Handle adapter  32  ( FIG. 11 ) is composed of injection molded plastic and adapts the round tapered end profile of handle  31  to the uniform square profile of tube  20 . Handle adapter  32  outer profile has the same dimensions as the inner cavity of tube  20 , and its inner cavity has the same dimensions as tapered end  36  of handle  31 . Holes  34  and  35  in handle  31  and handle adapter  32  match the size and separation of holes  24  and  25  in lever arm assembly  2 . 
     It should be noted here that a tapered end is currently the only configuration available for the preferred off-the-shelf handle that satisfies light weight, high strength, moderate flexibility and practical cost criteria for the invention. A customized handle would potentially eliminate the tapered end but the component cost would increase to the extent that the tool would not be practical to produce, except possibly at very high volumes. Alternatively the tapered end could be cut off but that would reduce the handle length by 80 mm and result in an undesirable reduction of maximum leverage ratio. 
     Jaw  4  and jaw  5  ( FIG. 12 ) are identical. Front surface  41  and rear surface  40  are 60 mm side-to-side and 80 mm top-to-bottom. The dimension from front surface  41  to rear surface  40  is 9 mm including the textured peaks. Front surface  41  is textured for improved gripping force on deformable plant material. Mounting rails  42  and  43  ( FIG. 13 ) extend the full length top-to-bottom of rear surface  40 , and 21 mm perpendicularly outward from the rear surface. The mounting rails are 8 mm wide and positioned symmetrically and parallel to each other on the rear surface with inner faces 15.75 mm apart and outer faces 31.75 mm apart. Corner bracing  44  and  45  at the bottom of rear surface  40  is 10 mm wide and extends from the outer faces of the rails to the rear surface to provide additional strength at critical stress points. Mounting holes  46  and  47  are 6 mm diameter and their centers are 10 mm perpendicularly outward from rear surface  40  and 30 mm from the top and bottom ends of mounting rails  42  and  43 , with the critical dimension being that they are centered 20 mm apart from each other. 
     Two additional components in the assembly are not clearly visible in  FIGS. 1-3 , spring  6  and spring retainer pin  7 , because they are obscured by lever arm assembly  2 . Detail views of the tool head with jaws open ( FIG. 14 ) and jaws closed ( FIG. 15 ) expose the spring components. Retractor spring  6  ( FIG. 16 ) is a custom wound torsion spring made of 1 mm diameter music wire. Torsion coil  61  is 4 coils with 6 mm inside diameter. Front mounting coil  62  is 3 coils with 6 mm inside diameter at the end of a straight leg of 32 mm length extending from torsion coil  61 . Rear mounting hook  63  is one half coil with 5 mm inside diameter at the end of a straight leg of 32 mm length extending from torsion coil  61 . The legs cross over each other at an angle of about 30 degrees. Spring retainer pin  7  ( FIG. 17 ) is a solid rod of mild steel 6 mm diameter and 31 mm length. 
     All bolts are hex cap M6×1 thread and each is secured with an M6×1 thread nylon insert lock nut. Front jaw  4  is mounted on the rear side of frame front arm  10  with the front surface facing toward the rear and is secured with bolts  48  and  49  of length 40 mm. Lever arm assembly  2  and handle assembly  3  are secured together with bolts  37  and  38  of length 50 mm. Lever arm assembly  2  is secured to the frame pivot hub with bolt  38  of length 50 mm. The lock nut for bolt  38  is tightened to the point where both bolt and nut make superficial contact with lever arm assembly  2  but allow freedom of movement for the lever arm assembly to pivot on frame  1 . Jaw  5  is secured to lever arm assembly  2  with bolt  50  of length 40 mm through the jaw lower mounting hole. The lock nut for bolt  50  is tightened to the point where both bolt and nut make superficial contact with the outer faces of jaw  5  mounting rails but allow freedom of movement for the jaw to pivot on lever arm assembly  2 . 
     Retractor spring  6  is mounted between jaw  5  and frame rear arm  12 . Spring rear hook  63  is inserted into frame spring mounting holes  18  and  19  with spring torsion coil  61  positioned upward. Spring retainer pin  7  is inserted through upper mounting hole  46  of rail  42  of jaw  5 , then through spring front mounting coil  62  and finally into upper mounting hole  46  of rail  43  of jaw  5  so that spring mounting hook  62  is positioned between jaw  5  rails  42  and  43 . Spring retainer pin  7  is press-fit into the jaw  5  mounting holes and is held in place by friction. Spring retainer pin  7  length is slightly less than the distance between the outer faces of the jaw mounting rails so that when fully inserted both ends are inset slightly from the mounting rail faces to avoid interference with movement of the mounting rails between the arms of lever arm assembly  2  during operation of the tool. 
     OPERATION OF THE INVENTION 
     Operation of the tool begins in rest position. In rest position no force is applied to handle  31  and the jaws are opened by retractor spring  6  as follows. Retractor spring  6  pulls spring retainer pin  7  toward frame rear arm  12 , so that the top of jaw  5  moves toward frame rear arm  12  and lever arm assembly  2  while jaw  5  pivots on bolt  50 . When jaw  5  rear surface  40  comes into contact with lever arm assembly  2 , the top of jaw  5  cannot move any further relative to lever arm assembly  2 . Retractor spring  6  then continues to pull jaw  5  and the bottom end of lever arm assembly  2  together toward frame rear arm  12  while lever arm assembly  2  pivots on bolt  8 . When lever arm assembly  2  comes into contact with rear arm  12  of frame  1 , the bottom end of lever arm assembly  2  cannot move any further relative to frame rear arm  12 . This is the rest position where the jaws are open to maximum separation from each other. 
     To remove a weed, the tool is placed in rest position with foot  13  flat on earth  99  and with weed stem  98  between open jaws  4  and  5  ( FIGS. 1 ,  14 ). For the most efficient operation the tool should be placed so that jaw  4  is initially in contact with weed  98  so that jaw  5  can close completely without the tool sliding on the foot to make contact between jaw  4  and weed stem  98  as described further below. 
     The operator applies force to handle  31  toward the rear of the tool which causes lever arm assembly  2  to pivot on bolt  8  so that the top part of lever arm assembly  2  moves toward the rear of frame  1  and the lower part of lever arm assembly  2  moves toward the front of frame  1 . As the lower part of lever arm assembly  2  moves forward it pushes jaw  5  forward until the bottom edge of jaw  5  front surface  41  is in contact with weed stem  98 . As handle  31  continues to pivot on bolt  8 , jaw  5  pivots on bolt  50  so that the top part of jaw  5  moves toward the front of frame  1 , counteracting the pull of retractor spring  6  on retainer pin  7 . When jaw  5  pivots sufficiently, front surface  41  makes full contact with and conforms to the taper of weed stem  98  ( FIGS. 2 ,  15 ), achieving maximum surface contact with weed stem  98 . At that point jaw  5  cannot pivot any further. 
     If the tool was placed initially so that jaw  4  is not already in contact with weed  98  as indicated previously for most efficient operation of the tool, continued force on handle  31  causes the tool to slide on frame foot  13  across earth  99 , moving jaw  4  toward weed stem  98  until it makes contact with weed stem  98 . Continued force on handle  31  results in tightening of jaw 4  and jaw 5  on weed stem  98 , compression of weed stem  98  structural material and intrusion of textured surfaces  41  peaks into weed stem  98  surface, further increasing gripping force and stability on weed stem  98 . With continued increase of force on handle  31  an equilibrium point is reached where compression, intrusion and foot movement cease and weed stem  98  is gripped optimally between jaw  4  and jaw  5 . 
     At that point frame  1  begins to pivot on the bottom rear edge of foot  13  ( FIG. 3 ), lifting the front end of frame  1  above earth  99  with weed stem  98  still gripped firmly between jaw  4  and jaw  5 , consequently pulling weed root  97  out of earth  99 . 
     The operator then releases the force on handle  31 , and the tool returns to rest position with the jaws fully opened as described previously, releasing the uprooted weed and automatically prepared for the next operation on another weed. 
     Automatic jaw retraction and release of the uprooted weed permits rapid repetition of tool operation. For example in the first timed test with a prototype model of the tool in a dense field of Teasel and Poison Hemlock plants ranging from about 120 cm to 200 cm tall, approximately 800 plants complete with roots were removed in 2 hours, on the order of 10 times as fast as the best rate at which such plants can normally be removed with generic pick and shovel tools. 
     SEQUENCE LISTING 
     Not Applicable

Technology Category: 1