Abstract:
A walk-behind power turf aerator having a rigid unibody construction and being shiftable into a highly compact configuration to facilitate transportation and storage thereof. The power turf aerator utilizes the reciprocal movement of a plurality of generally upright tines to create a relatively dense plug pattern in the turf.

Description:
This application is being filed contemporaneously with application for U.S. Des. Pat. Ser. No. 29/185,287, entitled TURF AERATOR, which is hereby incorporated by reference herein. 

   BACKGROUND OF INVENTION 
   1. Field of the Invention 
   The present invention relates generally to the field of turf aerators. In another aspect, the invention concerns walk-behind power turf aerators having a unibody construction and a compact configuration. 
   2. Description of the Prior Art 
   Walk-behind power aerators have been used for years to maintain healthy lawns by cutting and removing plugs from the turf. Due to the expense and infrequent required use of power aerators, most individual homeowners do not own a power turf aerator. Rather, the bulk of the power aerators in service today are owned by rental companies or professional lawn care providers. As such, power aerators are frequently transported from location to location either by individuals renting the aerator from a rental company or by professional lawn care providers servicing different clients. In the past, however, efficient transportation of power aerators has been encumbered by the high weight and bulky configuration of conventional power aerators. In most cases, a truck and/or trailer has been required to transport conventional power aerators because they would not fit in the trunk of a car. 
   Another disadvantage of conventional power aerators is the lack of structural rigidity of the aerator body. Power aerators are necessarily subjected to conditions of high mechanical vibration and repeated mechanical stress. Over time, conventional aerators which have been manufactured by bolting various body parts to a structural frame can require frequent maintenance and/or replacement of body parts which have been damaged or loosened during normal operation of the aerator. This problem can be especially pronounced when the power aerator is employed in a high-use situation, such as for power aerators owned by rental companies or professional lawn care providers. In addition, it has been discovered that many owners of conventional aerators fail to properly maintain their power aerators due to the difficulty of gaining access to the components needing routine maintenance (e.g., moving parts equipped with grease fittings/zerks). For example, many conventional aerators require a body panel to be unbolted in order to gain access to grease fittings that should be frequently used to properly lubricate the aerator. 
   Many conventional power aerators in use today employ a rotating rear “spoon” assembly equipped with a plurality (e.g., 20-50) individual spoons/tines extending radially from a common rotating shaft. When the spoon assembly is rotated by the motor, the spoons/tines penetrate into the turf and remove plugs therefrom. This traditional configuration has a number of disadvantages. For example, such a configuration causes the aerator to be very difficult to maneuver and typically requires additional “add-on” weights for effective operation. Further, such a configuration can only remove relatively shallow plugs and causes compaction of the soil and root exposure around the location where the plug is removed. In addition, the high number of relatively weak spoons/tines can necessitate frequent tine replacement, which is a time consuming and expensive activity. 
   SUMMARY OF INVENTION 
   It is, therefore, an object of the present invention to provide a power aerator that can be shifted into a highly compact configuration to facilitate transportation and/or storage of the power aerator. 
   A further object of the present invention is to provide a power aerator having a body with increased structural rigidity to thereby better resist the vibrational and load forces experienced during normal operation. 
   Another object of the present invention is to provide a power aerator that provides easy access to components which require regular maintenance. 
   Still another object of the present invention is to provide a power aerator that employs a minimal number of plug-removing tines, but creates a relatively dense plug removal pattern. 
   Yet another object of the present invention is to provide a power aerator utilizing high-strength tines that are easily replaceable. 
   A still further object of the present invention is to provide a power aerator which removes plugs from turf in a manner which causes minimal soil compaction and root exposure. 
   It should be understood that the above-listed objects are only exemplary, and not all the objects listed above need be accomplished by the invention described and claimed herein. 
   Accordingly, in one embodiment of the present invention, there is provided a turf aerator comprising a body having a unibody and a plurality of wheels rotatably coupled to the body and supporting the body for movement on the turf. 
   In another embodiment of the present invention, there is provided a turf aerator comprising a crank shaft assembly and a plurality of generally upright tines. The crank shaft assembly includes a rotatable crank shaft comprising a plurality of axially spaced plates and a plurality of eccentric bars. Each of the eccentric bars is rigidly coupled to and extends between a respective pair of adjacent plates. Each of the tines includes a connection portion rotatably coupled to a respective eccentric bar and a tip portion configured to cut and remove plugs from the turf. 
   In still another embodiment of the present invention, there is provided a highly transportable turf aerator that is shiftable between an operating configuration wherein the aerator can be used to remove plugs from the turf and a compact configuration wherein the dimensions of the aerator are minimized to facilitate transportation and storage of the aerator turf aerator comprises a substantially rigid body, a motor supported by the body, a plurality of tines shiftable relative to the body and powered by the motor, a plurality of wheels coupled to the body and providing for movement of the body on the turf, and a handle hingedly coupled to the body. The handle is shiftable between an extended position where it extends outwardly from the body and a folded position where it is over the body. The handle is in the extended position when the aerator is in the operating configuration, and the handle is in the folded position when the aerator is in the compact configuration. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the present invention is described in detail below with reference to the attached drawing figures, wherein: 
       FIG. 1  is a front isometric view of a power aerator constructed in accordance with the principles of the present invention; 
       FIG. 2  is a rear isometric view of the power aerator; 
       FIG. 3  is an enlarged cut-away front isometric view of the power aerator, particularly illustrating the unibody construction of the aerator body and the manner in which the crank shaft assembly is supported by the body; 
       FIG. 4  is an isometric assembly view of the crank shaft assembly and swingable tine guide positioned within and supported by the body of the power aerator; 
       FIG. 5  is an isometric assembly view of a tine of the power aerator, particularly illustrating the manner in which the tine connects to an eccentric bar of the crank shaft; 
       FIG. 6  is a sectional side view of the power aerator, particularly illustrating the swingable tine guide in an aeration position where the tines are positioned for cutting and removing plugs from the turf; 
       FIG. 7  is a sectional side view of the power aerator, particularly illustrating the swingable guide tine in a transportation position where the tines are positioned out of contact with the turf; 
       FIG. 8  is an enlarged side view of the base of a handle used to manipulate the aerator during operation, particularly illustrating the handle in an extended and locked position with a handle bar being locked in a handle base with a collar; 
       FIG. 9  is an enlarged side view similar to that of  FIG. 8 , particularly illustrating the handle being shifted out of the extended and locked position by sliding the collar off of the handle base and pivoting the handle bar in the handle base; 
       FIG. 10  is a side view of the power aerator in a compact configuration with the handle bar being positioned towards the front of the aerator to thereby minimize the height and length of the aerator; and 
       FIG. 11  is a top view of a preferred plug pattern which can be created by the inventive aerator. 
   

   DETAILED DESCRIPTION 
   Referring initially to  FIG. 1 , aerator  10  generally includes a body  12 , a plurality of wheels  14 , a motor  16 , a handle assembly  18 , and a guard bar  20 . Wheels  14  are rotatably coupled to body  12  and provide for movement of aerator  10  on a surface, such as the turf being plugged by aerator  10 . Wheels  14  can be any suitably strong conventional wheel assembly known in the art such as, for example, Gleason Corporation Model #99059450, available from Gleason Corporation of Milwaukee, Wis. Motor  16  is rigidly coupled to and supported by body  12  near the front of body  12 . Motor  16  is preferably a 5 horse power Briggs and Stratton Intekâ gasoline engine with a 6:1 gear ratio; however, motor  16  can be any suitable engine of similar horse power and gear ratio such as, for example, commercially available Honda OHV engines. Handle assembly  18  is hingedly coupled to the rear of body  12  and can be pivoted relative to body  12  between an operating position where handle assembly  18  extends upwardly and rearwardly from body  12  (as shown in  FIG. 1 ) and a transport/storage position where the handle is folded generally over body  12  (as shown in  FIG. 10 , which is discussed in detail below). Guard bar  20  is rigidly coupled to body  12  and extends generally upwardly and forwardly from the front of body  12 . Guard bar  20  includes a generally horizontally extending portion that is positioned in front of motor  16  and protects motor  16  from frontal impact. The horizontal portion of guard bar  20  also provides a convenient manual grasping location to facilitate lifting of aerator  10  onto or off of an elevated surface, typically during transportation or storage of aerator  10 . 
   Referring now to  FIGS. 1 through 3 , body  12  is comprised of a right side member  22 , a left side member  24 , a front member  26 , and a rear member  28 . Preferably, body  12  has a unibody construction. As used herein, the term “unibody construction” shall denote a manner of constructing an apparatus wherein sheet metal body parts are combined with stress-bearing elements to form the body and chassis of the apparatus as a single piece, as opposed to attaching body parts to a frame. It is preferred for members  22 , 24 , 26 , 28  of body  12  to be formed from sheet metal that has been bent to provide enhanced structural rigidity. As perhaps best shown in  FIG. 3 , a number of the edges of left and right side members  22 , 24  are bent in a generally U-shaped configuration, although a generally V-shaped or L-shaped configuration would also fBM_ 1 _BM_ 1 _unction to enhance the lateral strength of members  22 , 24 . In addition to providing enhanced strength, the bent edges of left and right side members  22 , 24  provide convenient locations for attaching a front cover  30 , a rear cover  32 , and a top cover  34  (shown in  FIGS. 1 and 2 ) to body  12 . The sheet metal used to form members  22 , 24 , 26 , 28  of body  12  is preferably a 4 to 16 gauge steel sheet metal, more preferably a 6 to 14 gauge sheet metal, and most preferably an 8 to 12 gauge steel sheet metal. Body  12  also includes a lateral support member  36  (shown in  FIG. 3 ) which extends between and is coupled to right and left side members  22 , 24 . Body  12  is preferably manufactured by unibody construction via permanently attaching members  22 , 24 , 26 , 28 , 36  to one another. As used herein, the term “permanently attaching” or “permanently attached” shall denote a manner of attaching two components to one another wherein the components cannot be detached without cutting or breaking the components apart. Preferably, members  22 , 24 , 26 , 28 , 36  are welded to one another. It can be seen from  FIGS. 1 through 3  that substantially all of the mechanical components of aerator  10  are supported on/by members  22 , 24 , 26 , 28 , 36  of body  12 . 
   As opposed to conventional power aerators which typically employ a non-sheet metal structural frame with sheet metal components bolted thereto, the sheet metal components (i.e., members  22 , 24 , 26 , 28 ) of inventive aerator  10  are actually load-bearing structural members. As perhaps best shown in  FIG. 3 , wheels  14  are directly coupled to right and left side members  22 , 24 . As used herein, the term “directly coupled” shall denote a manner of coupling two elements to one another wherein the elements directly contact one another, as opposed to having an intermediate structure disposed between the two elements. Right and left side members  22 , 24  each include a pair of reinforced openings that receive an axle of wheels  14 , thereby allowing wheels  14  to be rotatably coupled to right and left side members  22 , 24 . In this configuration, all of the weight of aerator  10  that is supported by wheels  14  is transferred to side members  22 , 24 . Thus, side members  22 , 24  bear a substantial portion of the weight of aerator  10 . Preferably, side members  22 , 24  bear a majority (i.e., more than 50 percent) of the weight of aerator  10 . 
   Referring now to  FIGS. 1 through 3  and  6 , front member  26  of body  12  extends between and is permanently attached to right and left side members  22 , 24 . Motor  16  is directly coupled to and entirely supported on front member  26 . As perhaps best shown in  FIG. 6 , the front edge of front member  26  is bent in a configuration which provides significant structural reinforcement to front member  26 . The bent configuration of the front edge of front member  26  presents a sloped surface to which guard bar  20  can be rigidly and permanently attached. The rear edge of front member  26  is also bent in a generally L-shaped configuration to provide significant structural reinforcement to front member  26 . As perhaps best shown in  FIGS. 2 and 6 , rear member  28  extends between and is permanently attached to right and left side members  22 , 24 . An upper portion of rear member  28  is bent in a generally V-shaped configuration to thereby provide significant structural reinforcement to rear member  28 . 
   Referring to  FIG. 3 , body  12  of aerator  10  houses and supports the internal mechanical components of aerator  10 . In particular, a crank shaft assembly  38  is directly coupled to, supported by, and extends between right and left side members  22 , 24 . Referring now to  FIGS. 3 and 4 , crank shaft assembly  38  generally includes a crank shaft  40  which is rotatably coupled to body  12  via bearings  42 , end plates  44 , and bolts  46 , 48 . Crank shaft  40  includes a plurality of substantially upright axially spaced plates  50  which are aligned along the axis of rotation of crank shaft  40 . Crank shaft  40  also includes a plurality of eccentric bars  52 , each disposed between a respective pair of aligned plates  50 . Eccentric bars  52  are offset from the axis of rotation of crank shaft  40 . Adjacent eccentric bars  52  are staggered relative to one another around the axis of rotation of crank shaft  40 . Crank shaft assembly  38  also includes a drive shieve  54  which is rigidly coupled to crank shaft  40  via bolts  56 . As best shown in  FIG. 3 , a motor shieve  58  of motor  16  powers a drive belt  60  which, in turn, rotates drive shieve  54  and crank shaft  40 . 
   Referring now to  FIGS. 3 through 5 , a plurality of tines  62  are rotatably coupled to eccentric bars  52  of crank shaft  40 . As best shown in  FIG. 5 , each tine  62  includes an end piece  64 , an elongated shaft portion  66 , and a connection portion  68 . Connection portion  68  couples each tine  62  to a respective eccentric bar  52 . Connection portion  68  includes a base  70  permanently fixed to shaft portion  66  and a cap  72  which can be removably coupled to base  70  via bolts  74 . Base  70  and cap  72  are configured to cooperatively define an opening through which eccentric bar  52  can extend. A bushing  76  is preferably disposed within the opening cooperatively defined by base  70  and cap  72  and extends around a narrow portion  78  of eccentric bar  52 . Narrow portion  78  of bar  52  and a wide portion  80  of bar  52  define a pair of shoulders  82  between which bushing  76  is disposed to thereby inhibit axial shifting of bushing  76  and tine  62  relative to eccentric bar  52 . Bushing  76  allows eccentric bar  52  to rotate freely within the opening cooperatively defined by base  70  and cap  72  of tine  62 . A grease fitting/zerk  84  is provided in cap  72  to lubricate bushing  76  and reduce wear caused by the rotation of crank shaft  40 . Thus, eccentric bars  52  and connection portion  68  cooperate to allow rotary motion of crank shaft  40  to be converted to reciprocal motion of tines  62 . End piece  64  of tine  62  is adapted to cut and remove plugs from turf when tine  62  is reciprocated into and out of the turf. End piece  64  defines an axially extending opening  86  which receives the cut plug from the turf. End piece  64  is preferably formed of a high-strength heat-treated metal that minimizes damage and wear to end piece  64 . End piece  64  also includes a male threaded portion  88  that cooperates with a female threaded end of shaft portion  66  and a lock nut  90  to thereby allow end piece  64  to be easily attached, removed, or replaced. 
   Referring now to  FIGS. 3 and 4 , aerator  10  includes a swingable tine guide  92  that generally includes a pair of laterally spaced side supports  94  and a guide plate  96 . The lower ends of side supports  94  are rigidly coupled to opposite ends of guide plate  96  so that guide plate  96  extends between the lower ends of side supports  94 . The upper ends of side supports  94  are pivotally coupled to right and left side members  22 , 24  via bushings  98 . Thus, swingable tine guide  92  is hingedly coupled to and supported by right and left side members  22 , 24 . Guide plate  40  defines a plurality of elongated slots  100 . As perhaps best shown in  FIG. 3 , each slot  100  is adapted to receive a respective tine  62 . During reciprocal motion of tines  62 , guide plate  96  maintains tines  62  in a substantially upright position. 
   Referring to  FIGS. 1 and 2 , handle assembly  18  includes a generally U-shaped handle bar  102  projecting rearwardly and upwardly from body  12  of aerator  10 . The upper end of handle bar  102  presents a generally horizontal portion which can be manually grasped by the user to facilitate manipulation of aerator  10 . Handle assembly  18  also includes a cross bar  104  to which a clutch lever  106  and an aeration/transport lever  108  are pivotally coupled. Clutch lever  106  and aeration/transport lever  108  can be shifted between a down position, wherein levers  106 , 108  are positioned closer to body  12 , and an up position, wherein levers  106 , 108  are positioned further from body  12 . Levers  106 , 108  each include a generally U-shaped handle portion which receives the generally horizontal portion of handle bar  102  when levers  106 , 108  are in the up position. Handle assembly  18  also includes a swingable lock  110  pivotally coupled to the generally horizontal portion of handle bar  102 . Swingable lock  110  is operable to selectively lock either clutch lever  106  or aeration/transport lever  108  in the up position. Clutch lever  106  is coupled to a clutch cable  112  via a spring  114 . Clutch lever  106  is operable to pull on or increase the tension in clutch cable  112  when clutch lever  106  is shifted from the down position to the up position. Aeration/transport lever  108  is operable to pull on an aeration/transport cable  116  when lever  108  is shifted from the down position to the up position. 
   Referring to  FIGS. 1 and 3 , when clutch lever  106  (shown in  FIG. 1 ) is shifted from the down position to the up position, clutch cable  112  causes a clutch shieve  118  (shown in  FIG. 3 ) to shift from a position to an engaged position. When clutch shieve  118  is in the engaged position, clutch shieve  118  provides sufficient tension in drive belt  60  so that the rotation of motor shieve  58  causes rotation of drive shieve  54  via drive belt  60 . When clutch shieve  118  is in the disengaged position, the tension in drive belt  60  is decreased to a level which allows motor shieve  58  to rotate without rotating drive shieve  54 . The shifting of clutch shieve  118  between the engaged and disengaged position is facilitated by a clutch plate  120  which is pivotally coupled to right side member  22  of body  12 . A spring  122  can be coupled between clutch plate  120  and body  12  to thereby bias clutch shieve  118  towards the disengaged position. 
   Referring to  FIGS. 6 and 7 , when aeration/transport lever  108  is shifted from the down position (shown in  FIG. 6 ) to the up position (shown in FIG.  7 ), aeration/transport cable  116  causes tine guide  92  to shift from an aeration position (shown in  FIG. 6 ) to a transport position (shown in FIG.  7 ). When tine guide  92  is shifted from the aeration position (shown in  FIG. 6 ) to the transport position (shown in FIG.  7 ), tines  62  are pulled from a substantially upright position to a less upright position by guide plate  96  of tine guide  92 . When tine guide  92  is in the aeration position, end pieces  64  of tines  62  can extend below wheels  14  so that plugs can be cut and removed from the ground  124  via the generally upright reciprocal movement of tines  62 . When tine guide  92  is in the transport position, end pieces  64  of tines  62  are swung into a position where they can not extend below wheels  14 , thereby allowing aerator  10  to be rolled across the ground  124  without interference from tines  62 . 
   Referring to  FIGS. 1 ,  2 ,  6 , and  7 , it can be seen that front, rear, and top covers  30 , 32 , 34  extend between and are releasably coupled to right and left side members  22 , 24 . Covers  30 , 32 , 34  are preferably formed from sheet metal of substantially lighter weight than the sheet metal used to form members  22 , 24 , 26 , 28  of body  12 . Preferably, covers  30 , 32 , 34  are formed from 14 to 24 gauge sheet metal, most preferably 16 to 22 gauge steel sheet metal. Top cover  34  is hingedly coupled to front cover  30  via releasable hinge  126 . Top cover  34  can be shifted between a closed position (shown in  FIGS. 1 ,  2 , and  6 ) and an open position (shown in  FIG. 7 ) by simply pivoting top cover  34  relative to front cover  30  at hinge  126 . Latches  128  are provided to hold top cover  34  in the closed position. However, latches  128  can be easily released to allow top cover  34  to be shifted into the open position. When top cover  34  is in the closed position, top cover  34  covers a substantial portion of crank shaft assembly  38 . When top cover  34  is in the open position, crank shaft assembly  38  is substantially uncovered and can be accessed from above to thereby allow for the performance of routine maintenance, such as lubrication of tines  62  via grease fittings/zerks  84 . 
   Referring to  FIGS. 1 and 8  through  10 , handle assembly  18  of aerator  10  can be shifted between an operating position (shown in  FIG. 1 ) and a transport/storage position (shown in FIG.  10 ). Handle assembly  18  includes a handle base  130  for hingedly coupling handle bar  102  to body  12 . Handle base  130  includes a channel  132 , a collar  134 , and a hinge  136 . Referring now to  FIG. 8 , when handle assembly  18  is in the operating position, handle bar  102  is locked in channel  132  by extending collar  134  around handle bar  102  and channel  132 . Referring now to  FIG. 9 , to shift handle assembly  18  out of the operating position, collar  134  is slid upwardly off of channel  132  and onto handle bar  102 . Handle bar  102  can then be pivoted upwardly and forwardly via hinge  136 . Channel  132  defines an opening  138  which allows the distal end of handle  102  to extend therethrough when handle assembly  18  is shifted out of the operating position. 
   Referring now to  FIG. 10 , when handle assembly  18  of aerator  10  is in the storage/transport position, aerator  10  has a very compact configuration. Preferably, the compact configuration of aerator  10  allows aerator  10  to be transported in the trunk of a standard mid-size or full size car. When handle assembly  18  is in the storage/transport position (shown in FIG.  10 ), it is preferred for the maximum height (h) of aerator  10  to be less than about 36 inches, more preferably less than about 30 inches, and most preferably less than 24 inches. When handle assembly  18  is in the storage/transport position (shown in FIG.  10 ), it is preferred for the maximum length (l) of aerator  10  to be less than about 48 inches, more preferably less than about 42 inches, and most preferably less than 39 inches. When handle assembly  18  is in the storage/transport position, it is preferred for the maximum width (w) of aerator  10  to be less than about 36 inches, more preferably less than about 30 inches, and most preferably less than 24 inches. The unibody construction of turf aerator  10  allows aerator  10  to have a significantly more compact configuration than conventional aerators using a frame-type construction. A significant advantage of the compact configuration of turf aerator  10  is the reduced wheel base (i.e., distance between the axes of rotation of the front and rear wheels) of inventive turf aerator  10 . It is preferred for the wheel base of turf aerator  10  to be less than about 36 inches, more preferably less than about 24 inches, and most preferably less than 20 inches. 
   Referring to  FIG. 11 , it is preferred for aerator  10  to create a relatively dense plug pattern in the turf. Preferably, the maximum distance (A) between plugs aligned along the direction of travel of aerator  10  is less than about 12 inches, more preferably less than about 10 inches, and most preferably less than 8 inches. Preferably, the maximum lateral distance (B) between plugs perpendicular to the direction of travel of aerator  10  is less than about 8 inches, more preferably less than about 6 inches, and most preferably less than 4 inches. Preferably, the density of the plugs in the turf is at least 6 plugs per square foot, more preferably at least 8 plugs per square foot, and most preferably between 10 and 15 plugs per square foot. 
   The preferred forms of the invention described above are to be used as illustration only, and should not be used in a limiting sense to interpret the scope of the present invention. Obvious modifications to the exemplary embodiments, set forth above, could be readily made by those skilled in the art without departing from the spirit of the present invention. 
   The inventor hereby states his intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as it pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.