Abstract:
A pre-starter for starting a turn in the end of a sod strip travelling up a conveyor in a sod harvester. The pre-starter includes a metal plate sloping downwardly and rearwardly with its end pressing against the sod strip to catch the blades of grass on the upper surface of the sod strip, thereby causing the end of the sod strip to curl upwardly. The curled end of the sod strip then moves into a conventional sod roll-up mechanism spaced immediately behind the pre-starter, to roll the sod strip. This forms accurate and consistent rolls suitable for automation.

Description:
PRIOR APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Application Serial No. 60/420,678, filed Oct. 24, 2002 entitled “SOD ROLL PRE-STARTER”. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to a pre-starter for use with a sod roll-up mechanism in a sod harvester.  
         BACKGROUND OF THE INVENTION  
         [0003]    Automatic sod harvesters which cut a strip of sod from a field of sod, and then form the cut strip into discrete rolls of sod, have been well-known since the late 1960&#39;s. More recently, there has been a trend to providing mechanisms which can receive and store a number of sod rolls, and which can then transfer the stored rolls onto a pallet. An example of such a mechanism is shown in U.S. Pat. No. 4,966,239 to Hutchison.  
           [0004]    In mechanisms which automatically handle and manipulate sod rolls, it is desirable for the rolls to be formed consistently. Preferably the start and end points of the sod strip which forms the sod roll should be accurately and consistently positioned, so that the roll handling mechanisms will have a minimal number of variations with which to deal.  
           [0005]    Normally the sod to be formed into a roll is located on a conveyor which carries the cut sod upwardly and rearwardly from a sod undercutting blade, to a sod roll-up mechanism. Such mechanisms include a starter for starting a turn in the end of the strip of sod travelling up the conveyor. These sod roll-up mechanisms have been very well-known for many years.  
           [0006]    A difficulty with prior art devices for starting a turn in the end of a sod strip is that they often perform inconsistently. In some cases they may fail to start a turn, and in other cases they may start a turn at different positions along the conveyor, thus causing the end of the sod strip which forms the roll to be located at different angular positions in the finished rolls. As mentioned, this is undesirable for automated sod roll handling equipment.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    It is therefore an object of the invention, in one of its aspects, to provide a pre-starter for starting a turn in the end of a sod strip travelling along a conveyor. The pre-starter is intended to operate in conjunction with a conventional sod rolling device which rolls the strip of sod the end of which has been turned up by the pre-starter.  
           [0008]    In one aspect, the invention provides a pre-starter for turning the end of a sod strip moving rearwardly along a conveyor, said strip having an upper surface and a rear edge, said pre-starter comprising a pressure member extending across said sod strip and having a rear end, a support for said pressure member, said support pivotably supporting said pressure member with said rear end thereof sloping downwardly and rearwardly to press against said upper surface of said sod strip to cause said end of said strip to curl upwardly.  
           [0009]    Further objects and advantages of the invention will appear from the following description, taken together with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0010]    In the drawings:  
         [0011]    [0011]FIG. 1 is a perspective view of a prior art sod harvester, showing an environment in which the pre-starter of the invention may be used;  
         [0012]    [0012]FIG. 2 is a perspective view of a portion of the sod harvester of FIG. 1 and showing a pre-starter according to the invention;  
         [0013]    [0013]FIG. 3 is a perspective view of a pre-starter according to the invention spaced in front of a conventional roll-up mechanism;  
         [0014]    [0014]FIG. 4 is another perspective view of a pre-starter according to the invention spaced in front of a conventional sod roll-up mechanism;  
         [0015]    [0015]FIG. 5 is a perspective view similar to that of FIG. 4;  
         [0016]    [0016]FIG. 6 is a side sectional view showing positioning of a pressure member of a pre-starter according to the invention as used; and  
         [0017]    [0017]FIG. 7 is a diagrammatic view of a modified pre-starter according to the invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0018]    Sod harvesters may be attached to a tractor for propulsion, or may be self-propelled. FIG. 1 illustrates a typical prior art sod harvester  10  such as that produced by Kesmac Inc. of Keswick, Ontario, Canada, for attachment to a tractor  11 . However, the invention is equally applicable to a self-propelled sod harvester, such as that shown in U.S. Pat. No. 4,966,239. In either case, the harvester  10  travels forwardly along a path of travel A.  
         [0019]    The sod harvester  10  includes a cutting head  12  containing a conventional ground roller  14  located behind a conventional cross cut blade  16 . The cross cut blade  16  is driven downwardly at periodic intervals (by a conventional drive mechanism  18 ) to form a transverse cut in the ground, so that the strip of sod which is to be cut by the cutting head  12  will be cut in lengths, each of which can be formed into a roll.  
         [0020]    The strip of sod to be cut travels beneath the roller  14  and is then undercut by a conventional undercutting knife  20 , which includes side cutting blades  22 , one at each side thereof. The undercutting knife  20  is mounted on arms  24  which are reciprocated forwardly and rearwardly in conventional fashion by a hydraulic motor (not shown), to cut a strip of sod.  
         [0021]    The cutting head  12  is mounted on a conveyor frame  30  which extends rearwardly from the cutting head. A main conveyor  32  having a planar upper flight is mounted in the conveyor frame  30  and carries cut sod rearwardly and upwardly from the undercutting knife  20 , to a sod roll-up mechanism  34  where the sod is rolled. The sod rolls are then delivered (in the prior art harvester shown) to a location where the operator can manually place the roll on a pallet (not shown) carried by the harvester.  
         [0022]    FIGS.  2  to  5  are perspective views of a portion of the conveyor and conveyor frame of the FIG. 1 sod harvester, showing the conventional sod roll starter and rolling mechanism  34 , and also showing a roll pre-starter  40  according to the invention. The conventional rolling mechanism comprises a roll-up frame  42  having sidebars  44  suspended by pivotably connected links from an upper part  48  of the conveyor frame (as is well-known in the art). The sidebars  44  are connected to each other by transverse rods  50 . At the front of the roll-up mechanism  34  there is a “flipper”  52  which is pivotably mounted so that it presents a flat transverse surface  54  which is contacted by the leading edge of the sod strip advancing rearwardly (with respect to path of travel A) up the conveyor  32 . The flipper  52  is biased to a vertical position by spring  56  which is connected between a post  58  on the flipper, and a mount  60  on one of the transverse rods  50 .  
         [0023]    When the leading edge of the sod strip contacts the flipper  52 , the flipper  52  pivots rearwardly, allowing the leading edge of the sod strip to pass beneath it and also tending to turn the leading edge of the sod strip. This starts the roll, and the rolling action then continues as the sod is carried upwardly and rearwardly along the conveyor  32 , with the upper edge of the roll being contacted by the transverse rods  50  of the sod rolling mechanism to create a roll-up action.  
         [0024]    As mentioned, a disadvantage of the standard roll-up mechanism shown and described is that the flipper  52  does not consistently start a turn in the end of the sod strip, so in some cases the sod strip moves partly underneath the sod roll-up mechanism  34  before its end turns and the roll begins to form. The parameters of the roll, including the location of the end of the sod strip on the roll, may then vary from one roll to another.  
         [0025]    The pre-starter  40  is spaced slightly forwardly of the conventional roll-up mechanism  34  and comprises a pressure member  70  (preferably comprising a plate of metal or the like) pivotably mounted at its forward end by tubular supports  72  on a cross-shaft  74 . The cross-shaft  74  is mounted on vertical posts  76 , one at each side of pressure member  70 . The posts  76  are secured (by bolts, not shown) to the conveyor frame  30 . Typically the vertical posts  76  are made adjustable forwardly and rearwardly, as well as vertically (by a series of spaced bolt holes), for fine tuning of the pre-starter, depending on the soil conditions.  
         [0026]    The pressure member  70  extends from tubular supports  72  rearwardly and downwardly toward the conveyor  32 , with the angle and spacing above the conveyor being controlled partly by the height of posts  76 , and partly by a cross bar  80 . The cross bar  80  is supported on the conveyor frame  30  by two bolts  82 , one at each side of the cross bar  80 , and is adjustable in height by reason of these bolts. The pressure member  70  rests on cross bar  80  when no sod is present and its rear edge is thus held (for example) about one-half inch to one inch above conveyor  32 . (The reason for this spacing is discussed below.) The angle which pressure member  70  forms with the upper surface of conveyor  32  is preferably between 10° and 80° and is most preferably between 25° and 60°.  
         [0027]    Two bolts  84  protrude from the upper surface of the pressure member  70  and are used for mounting weights on the pressure member  70 , if such weights are needed (again depending on soil conditions).  
         [0028]    Preferably, but not necessarily, the pressure member includes a wear plate  88  of rubber, plastic or other suitable material, secured to the underside of the pressure member  70  by bolts  90 . Wear plate  88  projects slightly rearwardly beyond the rear edge of the metal portion of pressure member  70 , for wear purposes, and is adjustable (by bolt holes  91 ) and replaceable.  
         [0029]    In operation, as the harvester  10  moves forwardly, a strip of sod  92  (only the end of the sod strip is shown) moves rearwardly up the conveyor  32  and travels beneath the rear edge  94  of the pressure member  70 . The rear edge  94  is as mentioned held slightly above conveyor  32  by cross bar  80 , partly so that it does not rest on and interfere with the actual conveyor surface, and partly so that it will be above the dirt portion  95  (see FIG. 6) of the sod strip  92 , and will contact and rub on only the grass blades  98  of the sod strip  92 . The height of cross bar  80  is adjustable for this purpose. Thus, the pressure member  70  does not actually roll the sod strip (which it would tend to do if its rear edge  94  hung below the dirt portion  95  of the sod), but it does press on the upper surface of the strip of sod with some force (adjustable by the angle and length of the pressure member  70  and any weights mounted on it), to catch the grass blades  98  of the sod strip  92 . This causes the end of the sod strip  92  to curl upwardly, as indicated at  96  in the drawings The upwardly curled end  96  of the sod strip then contacts the flipper  52 , which is as shown located closely rearwardly of the rear edge  94  of the pressure member  70 . Typically the spacing of flipper  52  behind rear edge  94  is one to four inches (and can be adjusted by moving posts  76  as mentioned, depending on sod conditions). Because the end of the sod strip is curled upwardly when it contacts the flipper  52 , the flipper will reliably cause the end of the sod strip to turn further, thus reliably starting a roll at the beginning of the sod roll-up mechanism  34 . Thus, the parameters of the sod roll (including the start and end parts of the sod strip forming the roll) will be more accurately defined.  
         [0030]    It will be appreciated that the dimensions of the pre-starter shown can vary. For example, the forward end of the plate pressure member  70  may be as little as about three inches above the conveyor  32  (it must be sufficiently spaced above the conveyor to allow sod to pass therethrough), or it can be as much as eight inches or more above the conveyor  32 . The pressure member  70  can vary in length, e.g. it can be as little as six inches long or as long as about two feet (or more), but typically it is about twelve inches long. In all cases, the pressure member  70  will slope downwardly toward the sod passing beneath it and will press on that sod with sufficient pressure to cause the sod to curl. If the sod is tough (e.g. formed from clay soil), then more pressure and hence more weight will be needed. If the sod is formed from sandy soil, then less pressure and less weight will be needed to cause the end of the sod to curl. Preferably the rear edge  94  of pressure member  70  is as mentioned hung above the dirt portion of the sod but below the top of the grass blades. Adjustment to suit soil conditions may thus be needed.  
         [0031]    In addition, while pressure member  70  has been illustrated as comprising a metal plate, other geometries may be used, e.g. a flat, thin transverse bar  98  (as shown in FIG. 7), with a forwardly extending strut  100  pivotably supported at its front end  102 . The bar  98  extends across the width of the sod strip  92  and may be weighted as needed (using weight receiving bolts  104 ) so that it will turn the end of sod strips moving up the conveyor  32 . Alternatively, any weights needed for the pressure member can be replaced by a biasing spring.  
         [0032]    Alternatively, pressure member  70  may be formed as a set of rearwardly extending, parallel, laterally spaced fingers which press on the upper surface of the sod strip.  
         [0033]    While a preferred embodiment of the invention has been described, it will be realized that various changes can be made, within the scope of the invention.