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The present invention relates to apparatus for reducing the number and size of clumps or clods or other aggregations of earthen material or for screening granular or aggregate material and in particular to such an apparatus that is attached to a skid-steer loader or other power source such as a tractor. 
     BACKGROUND OF THE INVENTION 
     Landscapers typically smoothly contour the ground surface before laying sod or planting bushes or flowers. Nutrient rich earth is the preferred base for such a use and where such soil does not exist at a particular site, it is often times transported there from a seller, such as a garden nursery. 
     To be readily and easily usable, especially by a home owner using hand tools to distribute contour, and landscape the soil bed, it is preferred that the soil, whether utilized from on-site supplies or delivered from a seller, is available for use without significant clumping or aggregation of the earthen material into clods. As anyone who has worked soil where large numbers of clods are found can attest, the presence of clods contributes to either extra work to reduce them or to an uneven surface. If left alone, large dirt clumps or clods may tend to disintegrate over time, but in doing so they leave a small pile rather than the desired even surface. Where soil is purchased from a seller, then, delivery without significant amounts of clods is required to minimize reworking of the soil at the site. 
     Compacted and aggregated soils affect not only garden nurseries, but also landscapers, construction companies, trenching companies, or anyone else that disturbs a site and must refinish it. For example, during construction of a new home, new topsoil may not be brought in from off site because the existing top soil may be adequate for the desired lawn and garden uses. During the actual construction, however, the topsoil may be cleared and piled for later replacement. As the soil sits in the pile, it can accumulate moisture and compact or aggregate into clods, resulting in clumps that require considerable reworking after replacement. Trenchers will also disturb the top soil layer, requiring replacement. Once again, a smoothly contoured surface is desirable before laying new sod or seeding. 
     To address this problem of soil clumps, soil pulverizers have been constructed to reduce soil “lumpiness”. Typically, these devices comprise rotating screening drums into which the soil is placed by another machine. These pulverizers are typically rather large and are designed to process significant amounts of soil at one time. Purchase and operation of such large scale pulverizers is therefore cost prohibitive for many, if not most, landscapers and soil retailers such as nurseries. Consequently, retailers such as garden nurseries tend to rent pulverizers on a short-term basis to process the soil in inventory while landscapers or construction companies may do the same to process soils used on-site. This processing may have to be done on a repeated and regular basis because even though once processed, as the newly pulverized and piled soil sits it absorbs moisture and once again clods can form. Pulverizing soil, then, is a continuing cost item for operators that do finish landscape work. Failing to pulverize the soil may result in the operation incurring additional labor and machine costs to achieve the desired soil bed contours while the present day pulverizing methods typically require bringing in the aforementioned large-scale pulverizers at additional cost. 
     It would be desirable to have a pulverizer that was economical to purchase and to use, that would readily process soil to reduce clumps; that provided the operator with the ability to readily change pulverizer screens; and that was easily transportable. 
     BRIEF DESCRIPTION OF THE INVENTION 
     It is an object of the present invention to provide apparatus that is not subject to the foregoing disadvantages. 
     It is an object of the present invention to provide apparatus for pulverizing material and screening the same. 
     It is another object of the present invention to provide apparatus for pulverizing soil clods and clumps and screening material that is cost effective for small businesses to own and operate. 
     It is still another object of the present invention to provide apparatus for pulverizing soil clods and clumps that is mountable to a skid-steer loader, tractor or other machinery. 
     The present invention provides a soil pulverizer for reducing the dumpiness or aggregation of soil into clumps or clods. In an embodiment of the present invention, the pulverizer may be mounted as an attachment onto an appropriate power source such as a tractor or a skid-steer loader. A pulverizer in accord with the present invention has a frame mounting a substantially cylindrically configured screening drum for rotation. The frame has a mounting bracket for attaching the pulverizer to the power source. The frame preferably mounts a protective shell or housing that partially encloses the screening drum. The frame may mount an attached scoop to the front thereof to facilitate guiding soil into the screening drum when attached to the tractor or loader. That is, the scoop may be pushed into a pile of dirt to push dirt into the screening drum. 
     A screening drum according to an embodiment of the present invention includes a cylindrical screen mounted to a shaft for rotation about the shaft longitudinal axis. The rear end of the shaft includes an attachment head having a recess configured to be attached to a drive shaft from a hydraulic motor or other appropriate power source. In the present embodiment illustrated herein, the attachment head includes a recess to receive non-rotationally the end of a power source drive shaft. To facilitate mounting the screening drum within the housing the scoop may include a slot to allow the forward end of the drum drive shaft to pass through. 
     The foregoing objects of the present invention will be fully understood and appreciated by those skilled in the art upon reading the present description in conjunction with the attached drawings illustrating an embodiment of the present invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the present invention showing it attached to the front end of a skid-steer loader, which is shown in phantom outline. 
     FIG. 2 shows the present invention in a front elevation view. 
     FIG. 3 depicts the present invention in a bottom plan view. 
     FIG. 4 illustrates the present invention is a side elevation, cross sectional view taken along viewing plane  4 — 4  of FIG.  2 . 
     FIG. 5 shows that portion of FIG. 4 indicated by the circle “A” in greater detail. 
     FIG. 6 illustrates the attachment of the screening drum shaft and the hydraulic motor in a cross sectional view taken along viewing plane  6 — 6  of FIG.  5 . 
     FIGS. 7A-7D depict the present invention in operation. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An exemplary embodiment  10  of a pulverizer in accord with the present invention is shown in FIGS. 1-7D and described hereafter. Pulverizer  10  is shown removably attached to a skid-steer loader  12 , shown in phantom outline. Pulverizer  10  includes a common attachment bracket  14  used to mount such equipment on such loader-type devices, but could be modified for attachment to a three-point tractor hitch found on typical farm tractors or any other desired equipment. 
     Pulverizer  10  includes a frame  20  comprising a screening drum housing  22  and a scoop  24 . Frame  20  is attached to the attachment bracket  14 . Housing  22  has a substantially semi-cylindrical, hollow configuration to receive a screening drum  26 . 
     Housing  22  includes front and rear sides  28  and  30 , and a partial, cylindrical shell  32  that extends upwardly from side panels  34 . Housing  22  includes an opening  36  at the bottom thereof to accommodate the insertion of the screening drum  26  into the interior of housing  22 , as will be more fully described below, best seen in FIG.  3 . 
     Scoop  24  can adopt many configurations within the scope of the present invention. As shown, the scoop in the embodiment of the present invention is formed by forwardly projecting side panel portions  38 , which extend substantially parallel to each other and substantially vertically, corner plates  40 , and blade portion  42 . Blade portion  42  includes a beveled blade  44 . The corner plates  40  are triangularly configured and extend between the side panel portion  38  along one edge, the blade portion  42  along a second edge, and the front side  28  of the housing  22  along the third edge. As noted, the scoop  24  can take other embodiments and could comprise a unitary configured member. Scoop  24  is provided to aid in presenting dirt to the screening drum  26  through the opening  46  of the front side  28  of housing  22 . 
     Screening drum  26  as shown in the illustrated embodiment of the present invention comprises a pair of support rings  50  that extend circumferentially and a plurality of supporting spokes  52  that extend radially between the rings and a screening drum shaft  54 . A screen  56  having the appropriately sized screening openings  58  is attached to the rings  50 . Screen  56  can be manufactured as a rectangular piece and then rolled around the support rings and attached thereto in a known manner. While the present invention is illustrated with a cylindrical screen, it will be readily observed that other regular geometrical figures could also be used for the screening drum  26 . 
     To aid in the ready insertion of the screening drum  26  into the housing  22 , it will be observed that scoop  24  advantageously includes a slot  60  to accommodate the shaft  54 . It will be observed from FIG. 4 that shaft  54  is longer than the length of the housing  22 . Thus, without the slot  60  in the scoop  24 , it would be difficult if not impossible to insert the drum  26  into the housing  22 . Referring to FIGS. 2 and 4 particularly, it will be observed that the shaft  24  engages a shaft retention plate  62  attached to the spokes  52  at the front end  64  of the drum  26 . The front end of the shaft  54  includes a mounting plate  66  that is used to attach the screening drum to the front side  28  of the housing  22 . Mounting plate  66  includes an appropriate bearing  68  through which the shaft  54  extends. 
     The screening drum  26  is rotated by a motor  70 , attached in any known way to the rear side of the housing  22 . As illustrated, the motor  70  is a hydraulic motor operating in conjunction with the hydraulic system of the loader  12 . Alternatively, motor  70  could be an electric motor operated off an electrical system or some other mechanical motor that would provide rotation to the drum  26 . Preferably, motor  70  is removably attached to the housing  22  to facilitate exchanges in the case of motor failure or some other need. 
     Referring particularly now to FIGS. 4-6, the rotational engagement between the shaft  54  and motor  70  will now be described in further detail. It will be observed that the present embodiment includes a motor mounting box  72  attached to the rear side  30  of the housing  22 . As illustrated, the mounting box comprises a cylindrical side surface  74  and a flat rear surface  76  to which the motor  70  is shown attached by bolts  78 . While the present embodiment includes a cylindrically configured mounting box, the present invention is not so limited and could readily include other configurations. 
     A motor drive shaft  80  extends from the motor  70  into a driving engagement with the screening drum  26 . It will be observed that the rear side  82  of the screening drum  26  preferably comprises a solid surface to prevent the material being pulverized or screened from falling out the back side and thus not being screened or pulverized. 
     The rear end  84  of the shaft  54  is attached to an Allen-type head  86 . A support plate  88  is preferably attached to the head  86  and the shaft  54  to stabilize the attachment therebetween. The head  86  is also attached to the rear side  82  of the drum  26 . Head  86  includes a non-circular recess  90  configured to receive relatively non-rotationally therein the appropriately configured motor drive shaft  80 . As shown, the motor drive  80  and the shaft recess  90  each have a regular six-sided or hexagonal configuration, though other configurations could also be used. 
     To mount the screening drum within the housing  22 , then, the rear end of the screening drum is first inserted into the housing such that the recess  90  engages the shaft  80 . The front end of the screening drum  26  can then be appropriately positioned so as to attach it to the front side  28  of the housing using the mounting plate  66 . In doing so, the forward end of the shaft  54  must pass through the appropriately provided slot  60 . 
     It will be understood that the present construction of the pulverizer  10  enables the user to obtain and use screening drums with screening apertures of differing sizes and configurations. This enables the user to readily change out the screening drum for different operations, such as soil pulverization or screening of aggregate or granular material. 
     With the construction of the pulverizer  10  described generally above, the operation of the present invention will now be described with reference to FIGS. 7A-7D. It will be observed with respect to FIG. 7A that the loader  12  has a pulverizer  10  in accord with the present invention attached thereto. The pulverizer  10  is attached to the hydraulic tool arms  92  of the loader  12 . Arms  92 , as is well known with such loaders, can be raised and lowered. Loader  12  is being used to push the pulverizer  10  into a pile  94  of material to be processed. In doing so, the blade  44  slices into the pile and the material is forced rearwardly onto the scoop  24  and into the drum  26 . Once the appropriate amount of material has been placed within the pulverizer and onto the scoop, the arms  92  of the loader will be raised to elevate the pulverizer  10  to the appropriate height as seen in FIG.  7 B. Raising the arms to tilt the pulverizer such that the front end is higher than the rear end will aid in the flow of material rearwardly into the drum  26 . 
     As shown in FIG. 7C, the pulverizer can be held level an appropriate distance above the ground and the motor  70  can be activated to start rotation of the drum  26 . The tumbling action of the material inside the drum  26  will result in the pulverization of the clods of materials and will also screen out undesirable material such as sticks or rocks sized in excess of the screen openings  58 . As seen in the Figure, the pulverized material  96  empties out of the screening drum  26  through the screen openings  58  to form a new pile of material  98 . 
     Referring now to FIG. 7D, once the desired amount of pulverization has occurred, the pulverizer  10  can be positioned with the arms  92  such that the rear end thereof is substantially higher than the front end and any oversized material can be emptied out of the drum  26  into a separate pile  100  to be handled later as desired. If desired, the drum rotation can continue during this stage to aid in emptying the drum  26  or it can be discontinued. 
     The present invention thus provides apparatus and method for pulverizing dirt clods or clumps and screening undesirable material from desired materials. The present invention can be manufactured for substantially less cost that presently available devices, thus making them readily affordable for a large number of potential users. It also presents the advantage over known prior art devices in that it can scoop up a load of dirt, then be moved to a desired dumping spot and the loaded soil can then be processed. 
     The present invention having thus been described, other modifications, alterations, or substitutions may now suggest themselves to those skilled in the art, all of which are within the spirit and scope of the present invention. It is therefore intended that the present invention be limited only by the scope of the attached claims below.

Summary:
A pulverizer for reducing the clumpiness or aggregation of soil into clumps or clods and for screening materials, the pulverizer having a frame mounting a substantially cylindrically configured screening drum for rotation and a scoop for aiding the delivery of the material to be pulverized or screened to the screening drum. The pulverizer may be mounted as an attachment onto an appropriate power source such as a tractor or a skid-steer loader.