Abstract:
An aerator is disclosed. The aerator features a rotatable tine assembly so as to avoid obstacles or aid in the extrication of the aerator therefrom. The tine assembly includes a plurality of tines mounted about a crank shaft and projecting through said retractor plate. Each tine rod passes between two rollers, one serving as a fulcrum is mounted directly on the retractor plate while the other is mounted upon a spring arm that biases the tine rod as far as possible into a forward position. The aerator is driven by the tines used to puncture the ground.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority as a non-provisional perfection of prior filed U.S. Provisional Application No. 61/614,338, filed Mar. 23, 2012, and incorporates the same by reference in its entirety herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the field of earth working and more particularly relates to an aerator. 
       BACKGROUND OF THE INVENTION 
       [0003]    The advent of agriculture required early farmers to work the land to their benefit, rather than gather as previously had been done. Early man developed many tools with which to work the soil and provide advantageous conditions for crop development. Over time, many tools have been developed for various purposes. On such purpose is the delivery of water, nutrients and air to the root system of the plant. This is particularly true in modern lawns, where grasses may form a thatch if merely left on the ground after being cut and ground becomes compacted over time. For this purpose, the modern aerator was developed. Aerators began with hand or foot tools that pierced holes in the thatch and ground and have since become mechanized and utilize a plurality of tines to progressively pierce thatch and soil. 
         [0004]    Modern aerators, for the most part, have similar concerns. First, holes need to be made with as little disturbance of the surrounding soil as possible. Accordingly, piercings by the tines must be made cleanly and tines must also be extracted cleanly. Second, piercings are ideally made at a depth determined by the operator of the machine. So, depth should be variable. Also, modern lawns in particular present obstacles that must be avoided or, if not avoided, must be worked around by the aerator. This can be particularly difficult to do and to also maintain integrity of surrounding soil as some tines are usually embedded within the soil at times when the aerator needs to be sharply moved to avoid an obstacle. 
         [0005]    The present invention is an aerator featuring a tine assembly that is rotatable about an axis parallel to the surface of the ground being treated. As such, tines are easily retracted from the ground if a blocking obstacle is encountered. Also, the rotation of the tine assembly allows for greater flexibility when moving across uneven ground. The aerator also features a biasing system that keeps tines in their most advantageous position in the cycle of piercing and withdrawing from the soil, despite the tilt of the tine assembly. 
         [0006]    The present invention represents a departure from the prior art in that the aerator of the present invention allows for a tilting tine assembly to be used in avoiding obstacles, extricating the aerator from obstacles and proceeding over uneven ground surface. Additional features maintain the tines in an advantageous forward position up impact with the ground for use in these objectives. 
       SUMMARY OF THE INVENTION 
       [0007]    In view of the foregoing disadvantages inherent in the known types of aerators, this aerator provides a tilting tine assembly. As such, the present invention&#39;s general purpose is to provide a new and improved aerator that is maneuverable around obstacles, is easily removed from obstacles when encountered and travels easily over uneven ground. 
         [0008]    To accomplish these objectives, the aerator comprises a rotatable tine assembly mounted to the frame of the aerator. A retractor plate is coupled to the tine assembly, but is independently removable therefrom. The tine assembly includes a plurality of tines mounted about a crank shaft and projecting through said retractor plate. Each tine rod passes between two rollers, one serving as a fulcrum is mounted directly on the retractor plate while the other is mounted upon a spring arm that biases the tine rod as far as possible into a forward position. 
         [0009]    The more important features of the invention have thus been outlined in order that the more detailed description that follows may be better understood and in order that the present contribution to the art may better be appreciated. Additional features of the invention will be described hereinafter and will form the subject matter of the claims that follow. 
         [0010]    Many objects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views. 
         [0011]    Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
         [0012]    As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a side elevation of an aerator manufactured according to the teaching of the present invention. 
           [0014]      FIG. 2  is a perspective view of the tine assembly of  FIG. 1 . 
           [0015]      FIG. 3  is a front plan view of the tine assembly of  FIG. 2 . 
           [0016]      FIG. 4  is an exploded view of the retractor plate assembly of  FIG. 2 . 
           [0017]      FIGS. 5A-5D  are side elevations of the tine assembly of  FIG. 2 , depicting one tine and the relative motions of the tine, crank shaft and aerator. 
           [0018]      FIGS. 6A-6C  are side elevations of the tine assembly of  FIG. 2 , depicting various adjustments of the retractor plate relative to the tine assembly. 
           [0019]      FIG. 7  is a side elevation of the aerator of  FIG. 1 , with the tine assembly tilted away from the ground. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    With reference now to the drawings, the preferred embodiment of the aerator is herein described. It should be noted that the articles “a”, “an”, and “the”, as used in this specification, include plural referents unless the content clearly dictates otherwise. 
         [0021]    With reference to  FIG. 1 , an aerator  10  comprises motor  16  mounted upon a chassis with wheels  18 . A handle  12  extends from the chassis and provides a mount for controls  14 . Also mounted upon chassis, is tine assembly  20 , which is operably connected to motor  16  by at least one belt. Retractor plate  28  is operably connected to the controls  14  and can be pulled by activating the controls  14 , thereby rotating the entire tine assembly out of a position of engagement with the ground, should the need to do so arise ( FIG. 7 ). The entire tine assembly  20  rotates about mounting point  19 . In operation, the retractor plate  28  is positioned downward and located properly by abutting stop  17 . 
         [0022]      FIGS. 2 and 3  depict the tine assembly in greater detail. Pulley  21  is operably connected to the belt of the motor  16  ( FIG. 1 ) and a rotating crank shaft  22 . At various locations about the crank shaft  22 , tine rods  26  are connected at heads  24 . The relative angle between each tine rod will be dependent upon the number of tines in the system. Ideally, tine rods  26  should be evenly spaced about the crank shaft, but not in sequential order. So, for an eight tine system, as depicted in the Figures, a tine rod  26  should be positioned every 45° about the crank shaft  22 . Heads  24  should be rotatable about the crank shaft  22  in order to keep the tine rods  26  pointing generally downwards. Ideally, crank shaft  22  should position the tine rods  26  so that two adjacent tine rods  26 , and associated tines  27 , are not impinging ground right after the other. This staggering of the tines  27  allows for better control of moments caused by the rotation of the crank shaft. 
         [0023]    Tine rods  26  extend through holes in retractor plate  28  and pass through a biasing system  30 , shown in better detail in  FIG. 4 . Retractor plate  28  features a number of upwards extending tabs  29  about the holes through which the tine rods  26  pass. Each tine rod  26  has a spring arm  35  and a fulcrum roller  34 . The spring arm  35  is essentially a frame with two opposing bars connected with a cross beam and each bar has two holes located at either end. The spring arms  35  and fulcrum rollers  34  are mounted on the tabs  29  by means of a retaining rod  32  that passes through coaxial holes in the tabs  29 , the lower set of holes in the spring arms  35 , torsion springs  37 , and fulcrum rollers  34 . Each spring arm  35  is biased by a torsion spring  37  into an upwards orientation and, at its extreme upper end, a bias roller  36  is mounted about an axle  38  passes through the upper holes in the spring arm  35  and is secured by clips  39  about the frame of the spring arm  35 . As seen in  FIGS. 2 and 3 , tine rod  26  is inserted between the crossbar of the spring arm  35  and the bias roller  36  such that the bias roller is behind the tine rod. Spring arm  35  then biases the tine rod  26  against the fulcrum roller  34 ; however, because of the give in the spring, it also allows the tine rod  26  to move backwards, away from the fulcrum roller  34 , as force is placed on the tine rod  26  through the cycle of motion of the tine assembly  20 . It should be noted that, in the preferred embodiment, both bias roller  36  and fulcrum roller  34  are grooved to lessen unwanted side-to-side movement of the tine rod  26 . 
         [0024]    Motion of the assembly is depicted in  FIGS. 5A-5D . As a tine  27  begins its travel, it begins in at an apex position. As crank shaft  22  rotates in a direction opposite the travel of the aerator, it pushes tine rod  26  and the associated tine downwards. Spring arm  35  forces the tine rod  26  forward ( FIG. 5B ). As crank shaft  22  continues, tine  27  reaches the bottom of its path of travel  25  ( FIG. 5C ) and is eventually retracted from the ground ( FIG. 5D ). The path of travel  25  is ovoid. This path of travel lessens the disturbance of the ground around the piercing and works the tine  27  out of the ground in a smoother action. The path of travel  25  is opposite the rotation of the crank shaft  22 . This motion  25  by the tines  27  actually provides the propulsion of the preferred aerator. 
         [0025]      FIGS. 6A-6C  depict adjustment of the tines&#39; path of travel  25  by adjustment of the retractor plate  28 . It should be noted in  FIG. 6A , the retractor plate  28  is in the lowest position and the resultant path of travel  25  is still ovoid, but narrower than that of the middle placement depicted in  FIG. 6B .  FIG. 6C  depicts the retractor plate  28  in the highest position, resulting in a wide path of travel  25 . This adjustment changes the speed at which the aerator travels, with higher retractor plate  28  settings resulting in higher speeds. It is significant to note that the change in speed is not derived from any change in the performance of the motor  16 . As such, the motor  16  need only run at a single speed. Since the tines  27  provide the motive force of the aerator  10 , it is necessary to provide a method of extraction should the tines become stuck. Certain impediments to the tines  27 , such as sprinkler heads, are avoided when the rotation of the tines  17  stops when one strikes an impediment. Then forward momentum of the aerator  10  moves the aerator past the impediment and, when the tine  17  is no longer blocked by the impediment, the tine  17  may then rotate again. Should this method fail, the tines  27  may always be extracted by rotating the retractor plate  28 , and entire tine assembly, out of the ground ( FIG. 7 ). This action would not only extract the tines, but also stop the forward motion of the aerator. 
         [0026]    It should be noted that the retractor plate  28  is removable from the tine assembly  20  without disturbing the assembly proper. 
         [0027]    Although the present invention has been described with reference to preferred embodiments, numerous modifications and variations can be made and still the result will come within the scope of the invention. No limitation with respect to the specific embodiments disclosed herein is intended or should be inferred.