Patent Abstract:
An aerator is provided having a front axle, including a differential and a tine wheel assembly which may be raised from the ground during maneuvers of the aerator while power continues to be supplied to the front axle, and a tine wheel assembly is provided which allows the operator to repair and change the configuration of the tines of the tine wheel assembly.

Full Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to lawn and garden equipment, in particular, the present invention relates to a lawn apparatus known as an aerator. Aerators are generally used to punch holes in soil or to remove cores from soil of approximately one half inch in diameter and three inches long to allow air and moisture and nutrients to enter the soil. 
     Several problems are present in existing aerators. The most common form of aerator has a reel or a tine assembly equipped with coring tubes or tines that are positioned on the reel or the tine assembly so they extend radially outwardly from the central shaft of the reel. The tines or coring tubes, in addition to providing aeration, provide propulsion for the aerator. As the assembly rotates, the tines rotate and punch into the ground to remove a core from the ground and also push the aerator forward. This arrangement provides excellent traction to propel the aerator along the lawn. However, it presents a substantial impediment to turning the device in a sharp turn, or to making a turn of sufficiently small radius to allow the operator of the aerator to make a second pass across the lawn immediately laterally adjacent to the previous pass. Typically, to accomplish a small radius turn, the user must expend substantial effort to force the aerator into position by lifting the front wheels or rear wheels of the aerator with the handle to remove the tines from the ground and to allow pivoting on one of the aerator wheels. Alternatively, if the tines are left in contact with the ground and allowed to propel the aerator, a turn having a large radius—on the order of eight to ten feet—only can be accomplished. As aerators typically weigh between two and three hundred pounds, the repetitive lifting of the device by the operator can be exhausting to the operator. This can present a serious problem during the operation of a reasonably dangerous piece of equipment. 
     Yet another problem that exists with current aerators is the assembly of the plugging or coring tines on the reel or tine assembly of the aerator. Typically, aerators have coring tines which are sandwiched between parallel mounting plates. The tines are held in place by bolts passing through the mounting plates and through the tines. The mounting plates are then, typically, welded onto a shaft or a tube which is then mounted onto a shaft to comprise the coring tube reel. It is very difficult, if not impossible, for a user of the device to replace individual components of such a welded tine wheel assembly. In addition, the connection of the tine wheel assembly to the frame of the aerator makes it difficult for a user to remove the tine wheel assembly if it is possible to replace any parts of the tine wheel assembly. 
     Therefore, it would be an advantage, and is an object of the present invention to provide an aerator which allows the user to change the direction of travel of the aerator while reducing the need to manually lift the aerator tines out of contact with the ground. 
     Yet another object of the present invention is to provide an aerator that offers a much smaller turning radius and allows the user to re-position the aerator on the reverse line of travel adjacent to the previous line of travel with greatly reduced effort by the operator and without the need to lift and pivot the aerator to achieve pivoting on the front support or wheel of the aerator. 
     Another object of the present invention is to provide a tine assembly which is easily removable from the aerator and which allows the operator of the aerator to easily change the type of tine which is mounted on the aerator and the number of tines and the spacing between individual tine wheels to allow near complete user selection of the type of aeration process being achieved. It would be a great benefit to users and the small equipment rental industry if an aerator was provided with a easily removable tine wheel assembly which allowed the user to replace any damaged part of the tine wheel assembly. 
     Yet another object of the present invention is to provide an aerator having a differential in the front axis of the device to allow great maneuverability of the aerator as it is operated. 
     Another object of the present invention is to provide a front axle having a differential in combination with castered rear wheels to further improve the maneuverability of the aerator. 
     SUMMARY OF THE INVENTION 
     The present invention provides an aerator having a tine wheel assembly which is easily removable by an operator. Further, the present invention provides a tine wheel assembly which allows the operator to change the spacing between tine wheels and to change the number and type of tines included in each tine wheel and to individually replace tines which have become damaged. A differential is provided in the front axle to increase maneuverability and to allow the user to reduce the need for manually lifting the aerator by its handle in order to and to reduce the need to remove the tine wheels from contact with the ground during the maneuvering of the aerator. The present invention also provides a combination of a front axle differential with castered rear wheels to assist in maneuverability of the device. Further, the present invention allows the tine wheel assembly to be raised from contact with the earth while power is supplied to the differential of the front axle to assist in maneuverability of the present invention. Another feature of the present is a non-welded, easily removable tine wheel assembly which permits the user to easily replace components of the assembly. 
     The foregoing and other objects are intended to be illustrative of the invention and are not meant in a limiting sense. Many possible embodiments of the invention may be made and will be readily evident upon a study of the following specification and accompanying drawings comprising a part thereof. Various features and subcombinations of invention may be employed without reference to other features and subcombinations. Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is the right side and top perspective view of the aerator of the present invention; 
     FIG. 2 is an enlarged fragmentary view of the tine wheel assembly of FIG.  8  and which is shown in FIG. 2 from a direction which is the reverse of that shown in FIG. 8; 
     FIG. 3 is a front and right side perspective view of a tine wheel; 
     FIG. 4 is an exploded view of the tine wheel shown in FIG.  3 . 
     FIG. 5 shows the lift handle of the present invention when not engaged; 
     FIG. 6 shows the lift handle of the present invention engaged to assist in lifting the present invention; 
     FIG. 7 is a front and top perspective view of the engine and power transfer assembly of the present invention; 
     FIG. 8 is a front and bottom perspective view of the present invention showing the differential on the front axle of the present invention and showing the tine wheel assembly in position on the front frame of the present invention; and 
     FIG. 9 is an exploded view of the engine and drive train of the present invention and showing the idler pulley and the connection of the drive chains to the differential and to the tine wheel assembly. 
     FIG. 10 is an exploded view of an alternative embodiment of the tine wheel shown in FIGS. 3 and 4 in which the shaft is triangular in cross-section. 
     FIG. 11 is an exploded view of an alternative embodiment of the tine wheel shown in FIGS. 3 and 4 in which the shaft is pentagonal in cross-section. 
     FIG. 12 is an exploded view of an alternative embodiment of the tine wheel shown in FIGS. 3 and 4 in which the shaft is hexagonal in cross-section. 
     FIG. 13 is an exploded view of an alternative embodiment of the tine wheel shown in FIGS. 3 and 4 in which the shaft cross-section has multiple longitudinal grooves. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, the preferred embodiment of the present invention is shown as aerator  10 . In its general configuration, aerator  10  is comprised of handle  12  which is attached to front frame  14  which contains the operational components of aerator  10 . Attached to front frame  14  is rear frame  16  which is pivotally connected to front frame  14  by bolts  18 . Castered wheels  20  are connected to rear frame  16  and allow the rear of aerator  10  to be easily moved any direction while relying on one of non-castered wheels  22  to act as a pivot for the move of castered wheels  20 . Front frame  14  also holds engine  24  which provides the power for forward movement of aerator  10  and which provides the power for rotation of tine wheel assembly  26 . Also mounted on front frame  14  is weight  28  which is fitted onto weight pins  30 . Weight  28  provides additional downward force on tine wheel assembly  26  to assist in forcing tines  32  of tine wheel assembly  26  into the ground as aerator  10  is operated. 
     Still referring to FIG. 1, aerator  10  is guided along its path by an operator grasping handle  12 . Within reach of handle  12 , the operator also can control rear frame lift bar  34  which is connected to rods  36  and which are attached to lift flange  38 . Lift flange  38  is pivotally mounted onto front frame  14  and is movable between a first position and a second position to raise or lower rear frame  16  with respect to front frame  14 . A user will wish to raise front frame  14  with respect to rear frame  16  when it is desired to disengage tine wheel assembly  26  from contact with the ground. Conversely, when the user wishes to engage tine wheel assembly with the ground, the user will pull rear frame lift bar toward handle  12  to raise rear frame  16  with respect to front frame  14  and thereby lower tine wheel assembly  26  into contact with the ground. Another component available to the user and which is mounted on handle  12  is engine throttle  40  which permits the user to advance the engine speed. Also mounted on handle  12  is power engagement bar  42  to which is attached cable  44 . As will be later described, cable  44  is connected to an idler pulley which compresses and releases a belt to transfer power between engine  24  and drive shaft  86  (FIG.  7 ). 
     Referring now to FIG. 2, tine wheel assembly  26  will be described in greater detail. Tine wheel assembly  26  is attached to front frame  14  by pillow bearings  46 . Use of pillow bearings  46  provides the advantage that when maintenance work must be performed upon tine wheel assembly  26 , the entire tine wheel assembly  26  may be removed conveniently and easily by simply unbolting pillow bearings  46  from front frame  14  and removing wheel assembly  26  from beneath aerator  10 . This easy removal of tine wheel assembly  26  and is an important feature of the present invention which, among its other benefits, allows the user to replace individual tines  32  or other component of tine wheel assembly  26  which have become damaged during use of aerator  10 . In addition tine wheel assembly  26  is assembled or constructed without any parts being welded together. Each part of the tine wheel assembly of the present invention can be disassembled thereby allowing the user to replace any part of the tine wheel assembly as desired. 
     Referring now to FIGS. 2,  3 , and  4 , the construction of tine wheel assembly  26  will be described in detail. Assembly  26 , in general, is comprised of a number of tine wheels  48  mounted on a shaft  50 . Tine wheels  48  are separated by spacers  52  which may be of whatever length the user believes to be appropriate for the work at hand. Each of tine wheels  48  is comprised of a pair of tine lock plates  54   a ,  54   b  which have secured therebetween a number of tines  32 . Tine lock plates  54   a ,  54   b  are spaced apart by plate spacer  53 . Plate spacer  53  protects shaft  50  and maintains tine lock plates  54   a ,  54   b  at the appropriate distance apart for the particular tine size which is mounted on tine wheel  48 . Each of tines  32  is held in place between the opposed tine lock plates  54  by a single mounting bolt  56 . The mounted tine  32  is further supported during operation by support bolt  58  which resists the force placed against tine  32  as tine  32  meets the ground during operation. 
     Referring now to FIGS. 3 and 4, the assembly of tine wheels  48  and tine wheel assembly  26  will be described. In FIG. 3, a tine wheel  48  is shown with five tines extending therefrom. It should be appreciated that a greater number or a fewer number than five tines can be assembled onto tine wheel  48 . This is accomplished through the use of either providing additional mounting holes or providing alternate tine lock plates  54  which are prepared to hold a greater or lesser number of tines. It will also be appreciated that in any of such tine lock plates which are used in tine wheel  48  that the diameter of the tines can be varied depending on the type of operation being performed. For example, in some cases, the operator may simply wish to use a narrow spike to poke holes into the ground and not actually remove a core of ground as will the tines  32  shown in FIG.  4 . In such a case the operator will simply change the length of spacers  52  and  53  to take-up any extra space along shaft  50 . 
     Referring now to FIGS. 4 and 10, each tine wheel  48  is assembled by securing each of tines  32  between tine lock plates  54   a ,  54   b  with mounting bolts  56  which pass through mounting void  60  of tine  32  and through the opposed tine lock plate  54  where the mounting bolt  56  is secured by a nut  62 . When the tines have been mounted between lock plates  54 , support bolts  58  are introduced to pass through tine lock plates  54  and also are secured with a nut  62 . When the assembled tine wheel is to be mounted on shaft  50 , shaft  50  is passed through drive engagement voids  66  of tine lock plates  54   a ,  54   b . It will be appreciated that drive engagement void  66  shown in the embodiment of FIG. 4 is rectangular in shape to match shaft  50  which also is rectangular. This shaping of shaft  50  provides a power transferring means which communicates the rotational power of the shaft from to shaft to at least one of tine wheels  48  while avoiding the use of welded connections between the shaft  50  and the tine wheels  48 . It will be appreciated that such welded or permanent connections between the shaft and the tine wheels or other device mounted on shaft  50  would prevent a user from being able to dismantle the tine wheels from the shaft to replace damages parts or to reconfigure the tine wheels on shaft  50 . Alternate shapes such as hexagonal or pentagonal cross-section, or triangular cross-section as shown in FIGS. 10 through 12, or otherwise having longitudinal grooves as shown in FIG. 13, and which are effective for transferring power also could be used for shaft  50  and drive engagement void  66 . Those skilled in the art will appreciate that a round shaft cross-section and a round engagement void  66  would not accomplish a transfer of power from shaft  50  to the tine wheel  48  which is slidably mounted thereon. 
     Referring now to FIGS. 5 and 6, a lift handle and lockout means will be described which permits the user to conveniently lift aerator  10  which is both a bulky and heavy object. Also the lift handle, simultaneously prevents rear frame  16  from collapsing against front frame  14  during the manual movement of aerator  10 . 
     Referring now to FIG. 5, lift handle  70  is shown in its unused position in which it is pivoted against rear frame  16  of aerator  10 . When the operator wishes to lift aerator  10  to place aerator  10  in the back of a vehicle or to lift aerator  10  over an obstacle such as a low wall or other obstruction, the user, after shutting down engine  24 , pulls rearwardly on rear frame lift bar  34 . This draws lift flange  38  into the position which lowers rear frame  16 , thus effectively raising front frame  14  and tine wheel assembly  26  off the ground. The user then grasps lift handle  70  and pulls outwardly causing lift handle  70  to rotate around pivot  72  and place lockout flange  74  underneath lift flange  38 . This prevents inadvertent shifting of lift flange  38  into the position which would raise rear frame  16  and which could result in the pinching of the fingers of the user&#39;s other hand or the fingers of another person who has placed their hands about rear frame  16  to assist in lifting aerator  10 . Once aerator  10  has been moved into its new position, user simply releases lift handle  70  which pivots back into its at rest position shown in FIG.  5  and restores lift flange  38  to an operable mode. 
     Referring now to FIGS. 7 and 8, the power train of the present invention will be described. As previously mentioned, the use of a front axle differential in combination with castered rear wheels assists in the maneuverability of aerator  10  and reduces the amount of effort required by the user to turn aerator  10  into a reverse path. This combination also reduces the turning radius required by the present invention as compared to other aerator devices. In FIG. 7, engine power takeoff pulley  80  is shown attached to engine  24 . Belt  82  passes around engine power takeoff pulley  80  and transfers the power to drive shaft pulley  84  which is part of power shaft  86 . Also mounted on power shaft  86  by means of gears are differential chain drive  88  and tine wheel assembly chain drive  90 . 
     Referring to FIGS. 8 and 9, the connection of differential chain drive  88  is shown on differential  92  and the connection of tine wheel chain drive  90  is shown connecting to a gear which is a part of tine wheel assembly  26 . It will be appreciated that engine power takeoff pulley  80  (FIG. 9) is always rotating when engine  24  is operating although use of engine throttle  40  may reduce or increase the amount of torque being applied to engine power takeoff pulley  80 . Therefore, as shown in FIG. 9, to engage and disengage the transfer of power from engine power takeoff pulley  80  to drive pulley  84  an idler pulley  98  is used to compress belt  82  sufficiently to cause rotation of drive pulley  84  or to release tension on belt  82  and to provide enough slack that drive pulley  84  does not rotate. Referring to FIG. 7, the tensioning and release of idler pulley  98  is accomplished by the user compressing power engagement bar  42  (FIG. 1) against handle  12  which causes tension on cable  44  which is passed to spring  94  which pulls on idler pulley flange  96  and compresses idler pulley  98  against belt  82  to transfer power from engine power transfer pulley  80  to drive pulley  84 . 
     It will be appreciated by those skilled in the art that at all times when drive pulley  84  is engaged, power is transferred to both tine wheel assembly  26  and to differential  92 . This allows the user to better manipulate the path of travel of aerator  10  when tine wheel assembly is engaged in the ground and especially when the tine wheel assembly has been disengaged from the ground as previously described. The combination of differential  92  on front axle  100  of aerator  10  and the castered wheels at the rear of aerator  10  and the ability to mechanically raise the tine wheel assembly while having power to the front axle, provides the user with far greater maneuverability of aerator  10  than is available in other conventional aerators which either do not have a front axle having a differential or instead of a front axle have a large hollow drum, usually filled with water, to add weight to the aerator. In a typical circumstance, the prior art type of aerator using a weighted drum as a front axle or an axle not containing a differential will require a turning radius of 10 to 15 feet to reverse the direction of the aerator. The present invention reduces this turning radius to a distance of 2 to 5 feet depending upon the slope of the ground being worked. 
     In the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover, the description and illustration of the inventions is by way of example, and the scope of the inventions is not limited to the exact details shown or described. Certain changes may be made in embodying the above invention, and in the construction thereof, without departing from the spirit and scope of the invention. It is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not meant in a limiting sense. 
     Having now described the features, discoveries and principles of the invention, the manner in which the inventive aerator is constructed and used, the characteristics of the construction, and advantageous, new and useful results obtained; the new and useful structures, devices, elements, arrangements, parts and combinations, are set forth in the appended claims. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Technology Classification (CPC): 0