Abstract:
An improved turf aeration device is provided, where the device has a frame having a journalled drive shaft, and the frame is attachable to a pulling vehicle having a power take-off portion; where the device has a power transfer means, attachable between the drive shaft and the power take-off portion, for transferring power from the power take-off portion to the drive shaft; and a plurality of aerator mechanisms operatively attached to the drive shaft and the frame, each aerator mechanism having a lower link member, with a base end and a distal end, where the base end is pivotally attached to the frame; a tine holder pivotally attached to the distal end of the lower link member, where the improvement includes a roller frame rigidly attached to the frame, the roller frame having two spaced apart, and a slideable member adapted to allow limited rotation of the aeration device toward or away from the pulling device.

Description:
This application claims priority to U.S. Patent Application Ser. No. 60/651,380 filed on Feb. 9, 2005, which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates to an improved soil aeration device. 
     II. Description of Prior Art 
     In grass fields and other lawn areas which experience sustained vehicular and pedestrian traffic, the turf surface and underlying soil can become undesirably compacted. The problems associated with soil compaction are that rain and fertilizing chemicals are prevented from fully penetrating the ground. The short-term effect of such a condition is that the field will remain soggy for longer periods after a rain, and the long-term effect is the prevention of deep and healthy root system and proper grass growth. Turf aeration is the process of creating channels in the soil so that water, air, and fertilizers can penetrate the ground and be dispersed effectively throughout the soil. 
     Many devices have been developed to alleviate soil-compaction problems ranging from pitchforks to heavy, tractor-pulled machinery having multiple, reciprocating tines. One tractor pulled heavy commercial device common in the industry today is the turf aerator manufactured by Verti-Drain® under U.S. Pat. No. 4,422,510 issued to de Ridder (hereinafter “de Ridder”), hereby incorporated by reference. That device teaches a main frame which supports several rotary shafts, drive links, and connecting rods which reciprocate a number of pantograph-type mechanisms. In each mechanism, a tine holder having soil-piercing tines is pivotally attached to an upper link in the mechanism, and a lower link supports a spring device which allows the tines to rotate within the soil to create a drain channel. The device is typically powered by the power take-off (PTO) drive of the pulling tractor. The chief advantage claimed by that reference is that the turf surface remains largely undisturbed because of the manner in which the path of the tines is substantially vertical during penetration and withdrawal due to the action of the pantograph mechanism. Examples of Verti-Drains are shown in  FIGS. 1-5 . 
     Another device common in the industry is the “Soil Reliever”, manufactured by Southern Green, Inc. and described in U.S. Pat. Nos. 5,709,272 and 5,570,746, both incorporated by reference in their entirety. The Soil Reliever is a tractor pulled device, PTO powered, and also has a main frame supporting a rotary shaft which drives upper links. Associated with each upper link is a lower link pivotally attached to the frame. The upper link connects to the lower link to cause the lower link to reciprocate. Pivotally attached to the distal end of the lower link is a tine holder, containing a number of removable times. Attached between the tine holder  30  and the frame, below the lower link, is a spring member for biasing the spring against a stop positioned on the lower link. Examples of the Soil Reliever are shown in  FIGS. 6-7 . 
     The main frames of both the Verti-Drain device and the Soil Reliever device contains a rotatable “front” roller (shown in  FIGS. 1 ,  5  and  7  as reference  10 ) attached to the main frame  6  (for reference purposes, the “front” of the aeration devise is the PTO end, that is, the end closest to the tractor). Front roller  10  is generally placed forward of the plane of the main frame, and hence, may be attached to the main frame with wings  15  as shown in  FIGS. 5 and 7 . Front roller  10  may be vertically adjustable as shown in  FIGS. 5 and 7 . Several Verti-Drain models also have a rear roller (shown as  12  in  FIGS. 2 ,  3  and  4 ) positioned rearward of the plane of the main frame  6  and behind the tine heads  30 . On these Verti-Drain devices, the rear roller  12  rotates in a frame  13 , and the frame  13  is generally pivotally connected to the main frame  6  of the device (See  FIG. 3 ). 
     Both the Verti-Drain and the Soil Reliever&#39;s main frame is connected to the tractor through a three point pick up harness on the device, generally consisting of two lower attachment points  100  rigidly connected to the main frame  6  and a top attachment point  101  also rigidly connected to the main frame  6 . See generally,  FIGS. 1 ,  5  and  8 . Powered adjustment arm  200  can be powered by the PTO, hydraulics or other means, and can include an intermediate arm positioned between the tractor powered adjustment arm and top attachment point (see  FIGS. 8 and 12 ). 
     Lower attachment points connect pivotally to arms on the tractor, and top attachment point  101  also pivotally connects directly or indirectly to a powered adjustment arm  200  on the tractor. The top attachment point  101  of the three point harness, as shown in  FIGS. 1 ,  5  and  7 , consists of two splayed arms  101   a  and a top rail  101   b . The two splayed arms  101  fixedly connect at one end to the lower main frame, and at the other end to the top rail  101   b . Top rail  101   b  is rigidly attached between the top of the main frame  6  and the two splayed arms. Additionally stiffening of the top rail  101   a  can be provided as shown in  FIG. 12 . The splayed arms  101   a  diverge from the top attachment point  101  to allow the PTO to attach therebetween, as shown in  FIG. 5 . The top attachment point  101  of the harness thus forms a rigid structure located between the bottom and top of the main frame  6 , and has a coupling means  101   c  (as shown, a pin, but other types of couplings could be used) to couple the top attachment point  101  to the tractor&#39;s powered adjustable arm  200 . 
     Hence, the aerator&#39;s three point harness is a rigid structure on the device but is pivotally mounted at the three connection points with the tractor or pulling vehicle. This three point harness is used in conjunction with the tractor&#39;s three point hitch system to raise and lower the aerator. When lowered or deployed, the aerator&#39;s front roller contacts the ground allowing the working end (the tines) to be placed in operational contact with the ground (shown in  FIG. 6A ). When lifted, the entire aerator is lifted off the ground (as shown in  FIG. 6B ) to allow for ease transportation of the aeration between working sites or locations. 
     The position of the working end of the device (the tine heads) with respect to the ground is set by adjusting the length of the pulling vehicles powered adjustment arm (or intermediary member)  200 . As this arm is shortened, the coupling point  101   c  of the top rail  101   b  to the powered adjustment arm  200  is drawn closer to the tractor, thereby raising the tine heads upwardly. As this powered adjustment arm  200  is lengthened, the coupling point  101   c  of the top rail  101   b  to the powered adjustment arm  200  is pushed further from the tractor, lowering the tine heads downwardly. If the tine head is not properly positioned with respect to the ground, entry angle and depth of penetration will be improper, as shown in  FIG. 18 . Hence, to keep the times in proper position with respect to the ground when covering complex terrain; the tractor operator must constantly monitor and adjust the length of the top adjustment bar. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of this invention to provide a turf aeration device which automatically adjusts position for changes in ground topography. 
     Yet another object of this invention is to provide a turf aeration device which can rotate away from the attachment points to the pulling vehicle. 
     It is an object of the invention to provide an aeration device having front and rear rollers connected in a rigid frame. 
     These and other objects and advantages of the present invention will no doubt become apparent to those skilled in the art after having read the following description of the preferred embodiment which are contained in and illustrated by the various drawing figures 
     Therefore, in a preferred embodiment, an improved turf aeration device is provided, where the aeration device is a frame having a journal led drive shaft, wherein the frame is attachable to a pulling vehicle having a power take-off portion; power transfer means, operatively attachable between the drive shaft and said power take-off portion, for transferring power from the power take-off portion to the drive shaft; and a plurality of aerator mechanisms operatively attached to the drive shaft and the frame. Each aerator mechanism comprises a link member, having a base and a distal end, wherein the base is pivotally attached to said frame; a tine holder, having at least one tine, pivotally attached to the distal end of the link member; a resilient means pivotally connected between the frame and said the holder; the improvement is a roller frame having fixedly attached to the main frame, and two rollers (or multiple wheels) attached rotatably to the roller frame, and a means to allow the aeration device to rotate away from the pulling device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view from the front end (the tractor end) of a prior art aerator device 
         FIG. 2  is a perspective detailed view of the rear section of the prior art aerator device. 
         FIG. 3  is a perspective rear view of a prior art aerator device detailing a rear roller. 
         FIG. 4  is another rear prospective view of the prior art aerator device detailing a rear roller. 
         FIG. 5  is a front view of a prior art aerator device detailing a front roller. 
         FIG. 6A  is a rear perspective view of a prior art aerator device in transit position. 
         FIG. 6B  is a rear perspective view of a prior art aerator device showing a front roller 
         FIG. 7  is a perspective view a prior art aerator device. 
         FIG. 8  is a schematic diagram of a prior art aerator device showing the rotation of the device. 
         FIG. 9  is a schematic side vie of the device in two different operational positions. 
         FIG. 10  is a schematic side view of the inventive device. 
         FIG. 11A  is a schematic side view of the time head Camber adjustments. 
         FIG. 11B  is a schematic side vie of the time head showing the operation of the spring system. 
         FIG. 12  is a top perspective view of the device showing the top spring an intermediate member. 
         FIG. 13  is a detail perspective view of the spring attachment to the frame. 
         FIG. 14  is a schematic side view with exploded detail of the top coupling means. 
         FIG. 15  is a detailed prospective view of the top coupling means. 
         FIG. 16  is a schematic side view showing the relative position of the device&#39;s components when positioned on a downward curved surface. 
         FIG. 17  is a schematic side view showing the relative position of the device&#39;s components when positioned on an upward curved surface. 
         FIG. 18  is a schematic side view of a prior art aerator device showing the relative position of the devices components when positioned on a flat surface (top), a downward curved surface (middle drawing) and an upward curved surface (bottom drawing). 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the drawings many details pertaining to fabrication and maintenance utility well established in the machine construction art and not bearing upon points of novelty are omitted in the interest of descriptive clarity and efficiency. Such details may include threaded connections, lockrings, shear pins, weld lines and the like. Unless otherwise specified, all parts are constructed of steel or of some other material suited to performing substantially the same function described herein. 
     Shown on  FIG. 9  is one embodiment of the improved aeration device, shown pulled by a tractor. Aerator has a main frame  6 . Located on the main frame  6 , with a gearbox interfacing the PTO, drive shafts, drive links, aeration mechanism, and connecting rods substantially as shown in FIG. 3 of the &#39;272 and a further description will not be repeated. As described in the &#39;272 patent, it is preferred that the aeration mechanisms be dynamically balanced on drive shaft, and that the primary shafts exiting the gearbox connect to the driveshaft through a pair of chain and sprocket assemblies. As before, such an arrangement balances power application and the torquing forces. 
     Fixedly attached to main frame  6  near the frame bottom are two wings  400  (one on each side) in which front roller  401  and rear roller  402  are rotatably mounted (multiple wheels could be used instead of the two rollers, but such an embodiment is not as stiff). The rollers  401 ,  402  and wings  400  creates a roller frame  404 , as shown, a rectangle shaped frame which is rigidly fixed with respect to the main frame  6 ; that is, the roller frame  404  does not pivot with respect to the main frame  6 . A pivoting roller frame  404 , while possible, is not preferred, as it would be difficult to control the entry angle of the tines. As the tines are located on arms connected to the main frame  6 , it is desired to be able to control the relationship of the main frame  6  to the ground. By allowing the roller frame  404  to pivot, this task becomes more complicated as the entry angle of the tines would vary (with respect to the ground tangent) with surface contour, an undesirable effect. However, the roller frame  404  could be adjustably connected to the main frame  6 , to allow for a fixed point of attachment, where the fixed attachment point could be varied as the job required. 
     To position the tine head  30  (and ultimately the tines) for proper placement in the ground, a compressive spring  40  is provided on a spring arm  41  located above each lower link  50 , as shown in  FIG. 10 . Spring arm  40  has one end pivotally connected to the tine head  30 , and the other end pivotally connected to the main frame  6 . The spring  40  operates to resist compression and hence, pushes the spring arm  41  rearwardly. Positioned around the spring  40  is boot  501 , to protect the spring  40  from becoming clogged. Obviously, a hydraulic piston or shock could be used in place of spring  40 . The rest position of the tine head  30  occurs when the spring is fully extended and the spring  40  is free from external compressive forces (hence, a tine holder stop is not required as an earlier device). The location of the spring arm  41  above the lower link arm  50  is distinct from that shown in the &#39;272 patent, where the spring was located below the lower link arm  50  and operated to restrain the tine holder  30  when subject to tension forces (stretching). It is not possible to use a spring  40  located underneath the lower link arm  50  when using a rear roller  402  positioned very close to the tine holders  30 , as the rear roller  402  would interfere with the operation of the spring. If the rear roller  402  is positioned behind the tine holder  30 , an underneath spring as disclosed in the &#39;272 patent could be used. However, such an arrangement implies a larger roller frame  404 , which as will be discussed later, has disadvantages. Obviously, instead of a spring, other biasing means can be utilized, as well as the pantograph push device as disclosed in the &#39;510 patent. 
     Also as shown in  FIG. 11A , the end of the spring arm  41  has a series of holes  43  positioned therethrough for varying the positioned of the tine holder  30  with respect to the spring arm  41 , thereby allowing one to modify the “rest” position of the tine holder to set the entry angle of the tines as needed for the particular application. Additionally, it is desired to mount the spring in a separate attachable bracket  60  positioned on the frame, to allowed for ease of removal, as shown in  FIG. 13 . The compression of the spring or biasing member for entry and exit of the tines is shown in  FIG. 11B . As shown, the spring motion in combination with the aeration device&#39;s motion results in a pivoting of the buried tine, helping to fracture the ground, enlarging the bottom of the penetration hole. 
     The main frame  6  and roller frame  404  provides a rigid structure that will follow the ground contours provided that the entire main frame structure  6  is free to rotate away from or toward the tractor. While the current designs of attachment systems allows the aerator to pivot about the attachment points, the aeration is not free to rotate in the plane of the pulling direction (toward or away from the tractor). One possibility to provide the needed degree of freedom would be to disconnect the tractor&#39;s powered adjustment arm  200  from the top arm  101   b  of the main frame&#39;s three point harness system  101 . In this fashion, the bottom of the main frame is allowed to pivot, and the top is free to rotate in the desired fashion: the main frame  6  is free to rotate about the lower attachment points  100  on the main frame  6 . Simply dispensing with this particular attachment point has drawbacks: the aerator cannot be placed in the raised position by action of the three point hitch system on the tractor. In this instance, upon raising the three point harness on the tractor, the aerator would flop downward (that is, it would continue to rotate rearwardly) without being lifted off the ground. 
     To provide for a limited range of rotation, the coupling means  101 C at the top attachment point  101  is modified to provide a means to provide limited rotation of the aeration device. As shown in  FIG. 14 , the means provided includes a spring retainer  202 . The retainer  202  has a protruding plate  202 A with a series of openings to allow for bolting of the plate  202 A to a matching set of openings on a plate member  102  positioned on the distal end of the attachment point  101 . As shown, the openings in plate member  102  are located in a channel formed by two plates, more clearly shown in  FIG. 15 . Bolted into this channel  102  is plate  202 A. The position of the spring retainer  202  can be shifted forward or rearwardly in response to the degree of rotation desired. As shown, plate  102  is angled to more closely align with the angle at which the power adjustment arm or intermediary member connects to the coupling means  101 C. 
     A spring arm  203  and spring  204  are positioned partially in the spring retainer  202 , as shown in the detail of  FIG. 14 . The spring arm is essentially a member slidable on the frame in a direction toward or away from the tractor. The slidable member could be a pin, plate, shock, etc. The distal end of the spring arm  203  is threaded, to allow a nut to be placed on the arm as it protrudes from the spring retainer  202 . The near tractor end of the spring arm has a coupling joint  205  (as shown, aligned holes and a pin) to couple to the power attachment arm (or intermediary arm) of the tractor&#39;s three point hitch system to the spring retainer  203 . 
     In operation, as the tractor traverses over a valley, the main frame  6  and roller frame  404  will rotate forwardly (toward the tractor) as shown in  FIG. 17 . Rotation is allowed by the spring retainer  202  moving forwardly with respect to the spring arm  203 , and results in compression of the spring  204 . The desired rotation could be achieved without use of the spring  204  (as the weight of the device is sufficient to provide for rotation) but the spring  204  helps damp the forces and prevents the spring arm  203  from slamming into the spring retainer  202 , potentially causing damage. As the tractor traverses over a ridge, the main frame and roller frame rotate rearwardly, reversing the operation, as shown in  FIG. 17 . 
     The amount of allowed rotation depends on the length of the spring arm (as shown about 12 inches) and the mount location of the spring retainer  202  on the plate(s)  102 . Additionally, the ability of the frame  6  to follow the contours of the ground will depend upon the footprint of the roller frame  404 . For instance, a small roller frame  404  (as shown in  FIG. 10 , the distance separating the rollers is about 27 inches) is more readily able to follow local features as opposed to a larger roller frame (say 48 inches, with the rear roller located behind the tine holder). While a larger roller frame  404  (including placing the roller in front of the tine heads are possible), it is preferred where features vary rapidly, such as on golf courses. 
     Although the present invention has been described in terms of specific embodiments, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. For example, it will be understood that by keeping the top attachment point only a pivot point, and placing springs and spring arms at the bottom attachment points of the three point harness, comparable rotation of the frame is achieved (here rotation about the top attachment point). It is therefore intended that the following claims be interpreted as coveting all such alterations and modifications as fall within the true spirit and scope of the invention.