Abstract:
A linear aeration apparatus is operable to form parallel linear aeration trenches into the surface of the ground. Aeration of highly compacted turf areas can be accomplished by first spreading a top dressing material over the surface of the field and then forming linear aeration trenches into the surface of the ground mixing the soil removed from the trenches with the top dressing material. A reciprocating finishing apparatus brushes the mixed soil back into the aeration trenches to stabilize the surface of the ground. A rotary member has radially projecting blades that, upon rotation, form the continuous linear trenches defining unstable islands of earth therebetween. The finishing device includes rearwardly projecting fingers that reciprocate transversely to brush the mixed soil and top dressing material back into the formed aeration trenches to stabilize the islands of earth.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims domestic priority on U.S. Provisional Patent Application Ser. No. 60/434,510, filed Dec. 18, 2002, the contents of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to turf aeration equipment used to loosen compacted soil by removing a portion of the soil therefrom and, more particularly, to an apparatus that provides for transversely spaced linear aeration trenches in conjunction with top dressing the turf to improve turf growth and drainage. 
   Aeration machines are well known in the art. These machines typically drive a hollow tine into the surface of the ground to create a plug of earth that is lifted from out of the ground above the surface and deposited on the surface of the ground. If the cores are to be disintegrated and swept back into the holes formed in the ground, the green cores, i.e. cores of earth freshly elevated from the moist ground, generally have to be dried for 2 to 4 hours, depending on the weather conditions, before the earthen portion can be removed from the vegetation thatch on top of the plug and associated root system. In some situations, such as golf course greens, it is preferable to return the earthen portion of the cores to the ground; however, the organic matter is typically removed from the aerated site. Alternatively, the earthen cores can be removed from the aerated site and taken to a remote location for subsequent handling. 
   For athletic fields, which often become highly compacted from extensive use, end of season aeration of the turf to enhance the growth of the grass is highly recommended. The process utilizing conventional hollow tine aerators is recommended to make multiple passes over the surface of the field to create enough open space within the turf to brush into the hollow spaces in the ground a calcined clay compound that is then top dressed over the field. Making multiple passes of an aeration machine takes a significant amount of time to accomplish and further causes compaction on the turf as the aeration process proceeds. 
   Accordingly, it would be desirable to provide a linear turf aeration apparatus that forms transversely spaced aeration trenches in the surface of the ground and then stabilizes the ground by sweeping non-compacted material back into the aeration trenches. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to overcome the aforementioned disadvantages of the known prior art by providing a linear aeration apparatus that forms transversely spaced, parallel aeration trenches to loosen the surface of the ground. 
   It is another object of this invention to provide an effective, yet inexpensive apparatus for aerating soil particularly on athletic fields. 
   It is an advantage of this invention that an extensive aeration can be effected on the surface of athletic fields. 
   It is a feature of this invention that the linear aeration apparatus is powered to effect a three-inch deep trench into the surface of the ground. 
   It is still another object of this invention to provide a finishing device that will be effective to brush mixed soil and top dress material back into the formed aeration trenches to stabilize the ground after passage of the linear aeration machine. 
   It is yet another object of this invention to provide a method of aerating athletic fields and other high use turf areas. 
   It is another feature of this invention that a top dressing material is deposited on top of the surface of the ground to be aerated before the aeration process. 
   It is another advantage of this invention that the soil removed from the aeration trench is mixed with the top dress material by the linear aeration machine to be swept back into the aeration trenches. 
   It is still another feature of this invention that the surface of the soil is stabilized by the filling of the linear aeration trenches with the top dressing material. 
   It is yet another advantage of this invention that drainage of athletic fields is improved by directing linear aeration trenches across the width of the field. 
   It is a further advantage of this invention that the aeration trenches can be oriented to control water flow with respect to the field. 
   It is a further feature of this invention that forming the aeration trenches transversely across an athletic field enhances the drainage of water off the crown of the field. 
   It is still a further feature of this invention that forming the aeration trenches longitudinally on an athletic field enhances the retention of water on the field. 
   It is still a further advantage of this invention that exceptional disruption of the turf on athletic fields and golf courses is attained when compared to conventional aeration methods using coring machines. 
   It is yet a further object of this invention to provide a method and apparatus for effectively aerating a turf area with a single pass of the aeration equipment. 
   It is yet a further advantage of this invention that subsequent passes over the field to break-up and/or remove aeration cores from the surface of the aerated ground is unnecessary. 
   It is still another advantage of this invention that the complete aeration process, including aeration and filling, can be accomplished in less time, thus saving in labor and operational expense. 
   It is a further object of this invention to provide a linear aeration apparatus that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use. 
   These and other objects, features and advantages are accomplished according to the instant invention by providing a linear aeration apparatus that is operable to form parallel linear aeration trenches into the surface of the ground. Aeration of highly compacted turf areas can be accomplished by first spreading a top dressing material over the surface of the field and then forming linear aeration trenches into the surface of the ground mixing the soil removed from the trenches with the top dressing material. A reciprocating finishing apparatus brushes the mixed soil back into the aeration trenches to stabilize the surface of the ground. The aeration trenches are formed by a rotary member having radially projecting blades that upon rotation of the rotary member form continuous linear trenches that define unstable islands of earth therebetween. The finishing device includes rearwardly projecting fingers that reciprocate transversely to brush the mixed soil and top dressing material back into the formed aeration trenches to stabilize the islands of earth. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows, in conjunction with the accompanying sheets of drawings. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention. 
       FIG. 1  is a schematic side elevational view of the linear aeration apparatus incorporating the principles of the instant invention; 
       FIG. 2  is a schematic front elevational view of the linear aeration apparatus shown in  FIG. 1 ; 
       FIG. 3  is a schematic rear elevational view of the linear aeration apparatus shown in  FIG. 1 ; 
       FIG. 4  is a left rear perspective view of the linear aeration apparatus; 
       FIG. 5  is an enlarged partial perspective view of the rotary trench-forming member and the cooperable presser members; 
       FIG. 6  is a schematic perspective view of the finishing device positioned behind the rotary trench-forming member; 
       FIG. 7  is a schematic side elevational view of the finishing device depicted in  FIG. 6  with the rearwardly extending fingers positioned adjacent the ground; 
       FIG. 8  is an enlarged perspective view of the eccentric drive for creating the transverse reciprocating movement for the finishing device; 
       FIG. 9  is a partial cross-sectional representation of a section of the ground after the aeration trenches have been formed therein prior to being filled by the finishing device; and 
       FIG. 10  is a process flow diagram defining the aeration process for a representative athletic field. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1-4 , a linear aeration apparatus incorporating the principles of the instant invention can best be seen. Any left and right references are used as a matter of convenience and are determined by standing at the rear of the machine facing toward the front hitch into the direction of travel. The linear aeration apparatus  10  includes a frame  12  having an attachment apparatus  14 , such as a conventional three-point hitch apparatus, for connection to a prime mover, such as a tractor or a skid steer loader (not shown). The attachment apparatus  14  and a pair of transverse, trailing castor wheels  13  support the frame  12  for movement over the ground G. 
   The frame  12  supports drive mechanism  15  that is connectable to the prime mover (not shown) to transfer operational rotational power therefrom for driving the operable components of the apparatus  10 , as described in greater detail below. The drive mechanism  15  can include a gearbox  16 , or other appropriate power transfer devices to provide the operational power to the rotary member  20  for forming the linear aeration trenches. The drive mechanism  15  can also include hydraulic lines  17  that can connect to the prime mover to circulate hydraulic fluid under pressure to hydraulic devices on the apparatus  10 , such as the hydraulic motor  18  for driving the reciprocating movement of the finishing device  30 . One skilled in the art will recognize that all drive functions could be either mechanically or hydraulically accomplished. 
   As can be seen best in  FIG. 1-5 , the rotary trench-forming member  20  is rotatably supported in the frame  12  transversely to the direction of travel at a location adjacent to the surface of the ground G. The rotary trench-forming member  20  includes a plurality of individual blades  23  extending radially from a cylindrical drum  22 . The blades  23  are preferably mounted in a spiral path around the periphery of the drum  22  so that the impact of the blades  23  with the ground G will be progressively spread across the transverse width of the drum  22 . Preferably, four or five blades  23  are mounted on the drum  22  at each station along the transverse width of the rotary member  20  with each succeeding station having the blades  22  indexed around the circumference of the drum  22  to form the spiral paths or groupings of the blades  22 . Preferably, the blades  23  are approximately one-half inch thick, i.e. the dimension extending parallel to the transverse width of rotary member  20 , and approximately three inches long, i.e. the dimension extending radially from the drum  22 . 
   The frame  12  also supports an assembly  25  of presser feet  27  spaced transversely in alignment with the blades  23  so that the blades  23  project between adjacent presser feet  27 . The assembly  25  of presser members  27  is positioned forwardly of the rotary trench-forming member  20  and the presser feet  27  project rearwardly to the forward periphery of the drum  22 . The rotary member  20  is driven to move the individual blades  23  forwardly through the presser members  27 . Accordingly, the blades  23  first engage the ground rearwardly of the assembly  25  of presser feet  27  and are driven down and forwardly through the ground G to form a trench  24  (best seen in  FIG. 9 ) approximately one-half inch wide and approximately three inches deep. 
   As the blades  23  exit the ground G forwardly of the axis of rotation of the drum  22 , the blades  23  move between adjacent presser feet  27  and drive the expelled soil that was formerly located in the now formed aeration trench  24  upwardly and around the top of the drum  22  to be discharged rearwardly of the rotary member  20 . The presser members  27  serve to hold down the areas of the soil adjacent the aeration trench  24  being formed, thus defining a discrete and clean aeration trench  24 . Clearly, the sequential engagement of the aligned blades  23  at each station along the transverse width of the rotary trench-forming member  20  cooperate in the formation of a linearly extending aeration trench  24 . As is best seen in  FIG. 9 , since the individual stations for the blades  23  are preferably spaced transversely approximately three and one-half inches from center to center, an island  29  of soil approximately three inches wide is flanked on opposing sides by an aeration trench  24  that is approximately three inches deep. 
   The process flow diagram of  FIG. 10  reflects that the aeration process begins with a placement of a top dressing material, such as calcined clay, sand or compost, or a mixture of these materials, that is spread over the surface of the ground in a relatively thin layer of approximately one quarter to one-half inch thick. As the linear aeration apparatus  10  is passed over the surface of the ground and the rotary trench-forming member  20  forms the aeration trenches  24 , the soil expelled from the trenches  24  is discharged rearwardly of the rotary member  20  on top of the top dressing still positioned on top of the islands  29  of soil. The operation of the trench-forming member  20  to throw the displaced material over the top of the rotary member  20  provides an aggressive action that effectively mixes the discharged soil and the top dressing material for subsequent engagement with a finishing device  30  described in greater detail below. 
   Referring now to  FIGS. 1 ,  3 ,  4  and  6 - 8 , the frame  12  also supports a trailing finishing device  30  that has a transverse width slightly greater than, or at least essentially the same width as the rotary trench-forming member  20 . The function of the finishing device  30  is to brush the discharged soil and top dressing material into the just formed aeration trenches  24 . A screen-like drag apparatus (not shown) and a rotary brush (not shown) were tried as finishing devices; however, the greatest success in performing the intended function for the finishing device  30  was obtained by a transversely reciprocating finger mechanism  30 . The finishing device  30  is formed in a somewhat similar manner to the presser finger assembly  25  in that a plurality of rearwardly extending fingers  32  are positioned into engagement with the surface of the ground G. The fingers  32  are mounted to (or formed as part of) a transverse support bar  33  that is elevated above the ground. The support bar  33  is connected to the frame  12  by a pair of pivoted arms  35 . 
   One of the arms  35  is operatively connected to a reciprocating drive mechanism  36  (best seen in FIG.  8 ), which is operatively powered by the rotating hydraulic motor  18 . The drive mechanism  36  is preferably formed with an eccentric driver  37  that is directly rotated by the hydraulic motor  18  and causes a transversely reciprocating motion because the pivot center of the eccentric driver  37  is offset from the rotational axis of the hydraulic motor  18 . A drive transfer link  38  interconnects the eccentric driver  37  and one of the pivoted arms  35  to transfer the reciprocating motion to the finishing device  30 . As a result, the fingers  32  are rubbed transversely in a reciprocating manner over the surface of the ground G to both mix the discharged soil from the formed trenches  24  and the top dressing material  29  and to brush the mixed soil and top dressing material into the formed trenches  24  to fill them with this mixed material. The net result is that the surface of the ground is very unstable with three-inch islands  29  of soil surrounded by three-inch deep trenches  24 . Any pressure, such as is found by a person walking on the ground would cause the islands  29  of soil to collapse into the adjacent trenches  24 . The filling of the linear trenches  24  by the soil/top dressing mixture, stabilizes the islands  29  with non-compacted material allowing an encouragement of turf growth. 
   The process of effecting an aeration of ground, such as a compacted athletic field and the like, starts with the application of a top dressing material to the surface of the ground, as is reflected in step  41  of the process  40  depicted in the process diagram of FIG.  10 . After a suitable layer of top dressing material is uniformly distributed on the surface of the ground, the linear aeration apparatus is run over the surface of the ground to first form linear aeration trenches  24 , reflected in step  42 , and then mixing the discharged soil and top dressing material in step  43  before brushing the mixed material into the formed trenches  24  to stabilize the islands  29 . For athletic fields, the linear aeration trenches  24  can be formed across the crown of a typical athletic field to improve drainage to the sides of the field. The aeration trenches can also be formed longitudinally on the athletic field to enhance water retention on the field. 
   The invention of this application has been described above both generically and with regard to specific embodiments. Although the invention has been set forth in what is believed to be the preferred embodiments, a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure. The invention is not otherwise limited, except for the recitation of the claims set forth below.