Abstract:
A subsoiling brush cutter hitch adapted for receiving a mower, a subsoiling shank, and optionally a coulter blade, enables combining activities for two dissimilar resource management practices, mastication (mowing) and subsoiling.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This invention is related to provisional application 60/691,734 entitled “Subsoiling Brush Cutter Hitch,” as well as commonly-owned U.S. patent application Ser. No. 10/781,487, now U.S. Pat. No. 5,059,072 entitled “Subsoiling Excavator Bucket” and to commonly-owned U.S. patent application Ser. No. 10/781,612, entitled “Subsoiling Grapple Rake”, both assigned to the United States of America, as Represented by the Secretary of Agriculture, and both herein incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION  
     Field of the Invention  
       [0002]     This invention relates to a multi-purpose implement for conducting dissimilar forest and soil management activities, mastication (mowing) and subsoiling (especially as related to soil productivity and restoration). The objective of mastication (mowing) is to reduce organic matter (live or dead vegetation) in an area for various purposes. The objective of subsoiling is to improve soil productivity by reducing soil compaction, which in turn improves soil tilth.  
         [0003]     The invention finds particular application in reforestation of newly-created skid trails, landings and legacy compaction areas, as it applies to the growth and vigor of natural and planted stock trees and shrubs in reforestation projects. New impacts occur when equipment is brought into an area on a short-term basis, such as for fire-line construction, and the remedial treatment takes place shortly thereafter. The expression, “legacy compaction” as used herein refers to compaction from previous long-term activities, particularly those involving operating heavy equipment on the soil surface. Examples of situations that lead to legacy compaction include repeated travel on road fill, skid trails, dozer pile slash treatment and soil deposition from erosion that occurs over a work site, such as equipment landings. Whereas compaction from new impacts typically resides 4-18″ below the soil surface, legacy compaction may be deeper, and also may be accompanied by hardpan formation. The greatest concentration of impacts tends to be from harvest, while the rising use of large equipment for mastication and fire suppression can also leave legacy impacts. Compaction has been associated with reduced mycorrhizal abundance and diversity in certain tree species, and also with ultimate growth rates and overall alteration of vegetation type.  
         [0004]     The benefits of minimizing the chance of negative long-term influences of compaction in managed stands of timber by treating compaction directly after it is created and providing for necessary ground cover are becoming increasingly apparent. The significance of this approach to forest management practice will increase as more importance is placed on use of stewardship contracting by land management agencies for restoration within managed plantations. The present invention will aid to reduce overall cost of this contract authority leading to a benefit to the area being restored.  
       DESCRIPTION OF THE PRIOR ART  
       [0005]     Previous mastication/mowing operations of shrubs and small trees typically involved the use of heavy equipment. For example, treatment may have been conducted by anchor-chaining two dozers together to drag the chain across the landscape. Alternatively, the operations may have been conducted using low ground pressure Bobcat-mounted mowers or cutter heads mounted on an excavator. Each of these pieces of equipment can produce its own soil impacts or accelerate existing soil impacts.  
         [0006]     Subsoiling has been proven to increase the survival and growth of seedlings in areas of previous compaction, but since there is a high cost associated with subsoiling, it is considered only after multiple planting failures and determination that a hardpan has indeed developed. Once a site has been replanted multiple times and has experienced surface losses of nutrient-laden soil, efforts to vegetate the area with desired stock may be greatly impaired regardless of renewed soil infiltration. Thus, after a ground-based harvest ends, skid trails and landings can be visible for years to decades.  
         [0007]     Subsoiling has been conducted with a dozer pulling an agricultural subsoiling implement or dozer-mounted ripper system. Dozer subsoiling is used to treat compacted forest soils as a last resort and is carried out as quickly as the operator can maneuver through the harvest unit. Thick brush, stumps, boulders, and standing trees can inhibit the dozer from treating all compaction in the unit. This approach to subsoiling reduces compaction, but does not allow return of organic matter of varying size to the soil. Also, mats of organic matter tend to accumulate under the agricultural implement, resulting in a loss of organic matter from the soil surface. Carelessness during the dozer subsoiling operation can also result in accumulation of rocks and boulders on the surface.  
         [0008]     Implements designed specifically for subsoiling are described by Williams et al. (U.S. Pat. No. 4,773,340), Gabriel (U.S. Pat. No. 5,121,800), and Grimm et al. (U.S. Pat. No. 5,605,196). Certain multi-functional implements, such as the spot-cultivation device of Willis (U.S. Pat. No. 6,067,736) are described in the literature. The implement of Willis is useful for both soil ripping and for raking.  
         [0009]     Other types of multi-functional earth-moving equipment have been disclosed in the patent literature. For example, Larson (U.S. Pat. No. 5,456,028) shows a backhoe bucket having a single ripper attached to the same coupling element that secures the bucket to the end of a hydraulically powered boom. The result is concentration of the force provided by the boom to the ripper tip. Larson depicts various embodiments for coupling the ripper to the boom, but none are amenable to use with a “quick change” connector (tool coupler). Moreover, the pivotal mount of the ripper to the back of the bucket is susceptible to eventual stress failure. In Publication No. US 2003/0167661, Larson discloses an improvement in which the ripper is secured to a tool coupler to permit its use with a wide variety of interchangeable excavation tools.  
         [0010]     Pruit (U.S. Pat. No. 6,490,815) shows an excavating bucket having a single ripping tooth or a pair of ripping teeth projecting rearwardly from the rear wall of the bucket. By virtue of this design the motion for functional operation of the ripper is opposite that of the bucket. In making a sweeping motion, the operator is able to alternatively break up hard material and scoop it up for removal. Fryrear (U.S. Pat. No. 4,041,624) describes integral rippers affixed to a hydraulic excavator bucket.  
       SUMMARY OF THE INVENTION  
       [0011]     We have now devised a combination subsoiling brush cutter hitch that enables combining activities for two dissimilar resource management practices, mastication (mowing) and subsoiling. The objective of mastication (mowing) is to reduce organic matter (live or dead vegetation) in an area for various purposes. The objective of subsoiling is to improve soil productivity by reducing soil compaction which in turn improves soil tilth. The hitch is designed to be compatible with many existing manufactured mastication/mowing heads and incorporates a subsoiling shank and wing, and optionally a coulter blade for cutting through organic material.  
         [0012]     It is an object of this invention to provide a multi-purpose implement for mastication and subsoiling, and optionally for cutting through organic materials on or beneath the soil surface.  
         [0013]     Another object of the invention is to provide a multi-purpose implement that will improve soil moisture retention of treated soil from the creation of organic ground cover (mulch), and will enhance micro site conditions for reforestation or other plantings.  
         [0014]     It is also an object of the invention to create a bridge in forest management practice that will reduce the chance of negative long-term influences of compaction in managed stands of timber by treating compaction directly after it is created and providing for necessary ground cover.  
         [0015]     A further object of the invention to reduce cost of reforestation in sites of newly impacted areas.  
         [0016]     Yet another object of the invention is to provide an approach for decommissioning temporary harvest roads, skid trails and landings without the need for two different pieces of heavy equipment or for multiple entries with heavy equipment.  
         [0017]     It is an additional object of the invention to reduce potential of multiple inter-planting failures in legacy compaction.  
         [0018]     Still another object of the invention is to create an activity which can efficiently treat the fuel loading, manipulate vegetation and improve soil productivity, without leaving an equipment footprint long-term.  
         [0019]     Other objects and advantages of this invention will become readily apparent from the ensuing description. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0020]      FIG. 1  is an oblique view of the subsoiling brush cutter hitch for combining multi-purpose implements including a mower, subsoiler, and optional coulter blade affixed to an excavator boom having in combination therewith a thumb attachment.  
         [0021]      FIG. 2  is a side elevation view of the subsoiling brush cutter hitch including the masticator, subsoiling shank, and coulter blade.  
         [0022]      FIG. 3  is a cut-away top view of the motor and hose housing of the implement shown in  FIG. 2 . The drawing shows the motor (circle with crosshair) to the left, belt attached to the spindle on the right, and a spring-loaded tensioning bolt for support and belt tension.  
         [0023]      FIG. 4  is a close-up view of the implement of  FIG. 2  showing the placement of the motor, belt, spindle and cutter disc. Not shown are the cutting teeth on the disc or position of the tensioning bolt.  
         [0024]      FIG. 5  is a side view of the subsoiling brush cutter hitch with subsoiling shank or wing (ripper point).  
         [0025]      FIG. 6  is a front view of the subsoiling brush cutter hitch.  
         [0026]      FIG. 7  is a top view of the subsoiling brush cutter hitch with access plate for motor housing and hose access removed.  
     
    
     DETAILED DESCRIPTION  
       [0027]     As illustrated in  FIG. 1 , the subsoiling brush cutter hitch  1  of the invention comprises as its principal components a framework for supporting a mastication (mower)  2  having a blade opening  3 , a subsoiling shank  4  equipped with a ripper point  5 , with or without wing tips  17  and optionally a coulter blade  6 . The hitch  1  is designed to attach to an excavator boom  7  equipped with an excavator thumb  8 . The framework also comprises a mounting bracket  9  for mounting of the hitch to the appropriate linkages of an articulated excavator boom  7  as shown in  FIG. 1 . The mounting bracket  9  comprises a pair of opposing flanges  10  for supporting pins  18  adapted to be engaged by a coupler  11  connected to the boom  7 .  
         [0028]     The masticator (mower) 2  may be any conventional tree- or brush-cutting implement as known in the art. In a preferred embodiment of the invention, the masticator  2  comprises a rotating blade  12  (i.e. a solid disc) having cutting teeth  22 , which are well known, positioned on its outer edge (as shown in  FIG. 4 ). The blade  12  and cutting teeth  22  spin in a plane of rotation determined by the orientation of the hitch  1  as manipulated by the excavator boom  7 . The blade or disc  12  may be enshrouded in a masticator or blade head or deck or opening  3 , and is preferably indirectly driven by a motor  13  and belt  14  ( FIGS. 3 and 4 ). The belt  14  would be provided with a spring-loaded tensioning bolt  15  for support and belt tension.  
         [0029]     The shank socket  16  ( FIGS. 1 and 2 ) is adapted to receive and secure the proximal end of a subsoiling shank  4 . The distal end of the shank  23  is a substantially pointed earth-working tool, such as a hardened, abrasion-resistant ripper point  5  having one or more wing tips  17  lying in a plane substantially perpendicular to the plane of penetration of the subsoiling shank  4 . The shank  4  is inserted into the open end of the socket  16  and will typically be held in place in the socket  16  by means of suitable fasteners that will permit easy removal and replacement. The curvilinear subsoiling shank  4  is oriented so that it is in an operating position when the masiticator head  2  is substantially vertical to the ground. In the preferred embodiment, the shank  4  length is sufficient to subsoil at a depth of approximately 24-30″ below the soil grade, and the shank  4  is positioned in an opposing relationship to the excavator thumb  8  on the boom  7  so that it can cooperate with the boom  7  for grasping objects.  
         [0030]     The subsoiling shank  4  can be a standard commercial part (e.g. John Deere® part number A24206) or similar fabricated steel shank, typically having a curvilinear profile. The shank  4  length and degree of curvature will determine the maximum depth of subsoiling. With a given shank  4 , the equipment operator can control the actual depth of penetration into the soil, and thus the actual depth of decompaction. Depending on the depth of compaction and the subsurface strata (e.g. rock), the maximum operating depth can be controlled by means of both the shank length and operator control. It is also envisioned that the subsoiling depth can be varied by providing multiple mount positions within the socket  16 . The use of ripper points  5  on the subsoiling shanks  4  can be standard commercial parts, such as John Deere® 5″ or 7″ sweeps (Part No. N236012). The size and angle/slope of wing tips  17  can vary depending upon desired lateral fracture of compacted soil being treated.  
         [0031]     In the preferred embodiment of the invention, the subsoiling brush cutter hitch  1  of the invention is also equipped with a coulter blade  6  as illustrated in  FIGS. 1 and 2 . The coulter blade  6  leads the subsoiling shank  4  through the soil, cutting grass mats and organic matter, surface or subsurface roots, etc. The position of the coulter blade  6  between the framework of the hitch  1  and the subsoiling shank  4  serves to extend the maximum effective subsoiling depth.  
         [0032]     In one embodiment of the invention, the implement or implement coupling  11  is equipped with a vertical orientation device (not shown) to provide feedback to the operator in regard to the attitude of the subsoiling shank  4  with respect to the soil surface. The orientation device may consist of a simple visual indicator, or may comprise an electrical and/or electronic device, such as a mercury switch and logic circuit with visual, auditory or other sensory signal as known in the art.  
         [0033]     As previously stated, the articulated excavator boom  7  shown in  FIG. 1  may also be equipped with a thumb  8  such as that described by Pisco, U.S. Pat. No. 5,813,822, herein incorporated by reference. The thumb  8  would typically comprise one or more fingers which would cooperate with the subsoiling shank  4  to collectively serve to grasp small objects or material such as brush, logs, rocks, and other logging debris that need to be placed into piles or moved from one location to another.  FIGS. 5, 6 , and  7  further illustrate the invention.  
         [0034]     By control of the excavator boom  7 , the equipment operator can alternate from one mode to the other. Thus, while one mode of the implement is oriented in an operable position, the other mode is in an “idle” position. During subsoiling, the boom  7  is extended away from the excavator, the mower  2  is pivoted so that it is substantially vertical to the ground, thereby employing the distal ends of the subsoiling shanks  4  into the proper position for movement through the soil: in a plane beneath, and generally parallel to, the soil surface. The implement is lowered toward the ground until the shanks  4  penetrate the soil to the desired depth. As the boom draws the implement toward the excavator, the point-forward subsoiling shank curvature tends to draw the shanks  4  down into the soil so that the proximal ends of the shanks are substantially perpendicular to the ground and distal ends are substantially parallel to the ground. As the shanks  4  slice through the soil, the earth-working ends move through the soil along a path that is in a plane beneath, and generally parallel to, the soil surface. The desired effect of the subsoiling operation is obtained when the path of the earth-working ends is below the level of hardpan or other soil compaction. Thus, the depth of the plane should be sufficient to allow vegetation and tree roots adequate depth of soil decompaction to thrive. During movement of the subsoiling shanks  4  through a zone of hardpan or soil compaction, the curvilinear shanks  4  and wing tips  17  impart an uplifting of the entire column of soil above and in front of the subsoiling shank  4  and cause a fracturing of the hardpan and other soil strata. The lifting of the soil column takes advantage of the plate-like or massive compacted soil structure to extend the lateral fracture to approximately 7-12 inches to either side (depending upon soil type and wing tip  17  selection) from the centerline of the subsoiling shanks  4 . The result is both a vertical and lateral decrease in the bulk density (or loosening) of the soil profile.  
         [0035]     When a sizeable object such as a large root or tree branch is encountered during the subsoiling operation, the equipment operator obtains optimal functionality of the coulter blade  6  by tilting the sharpened edge thereof toward the ground, thereby pinning the object against the soil as the blade slices through it. This has the effect of imparting a guillotine action and enhancing the downward, shearing force on the object. Shearing the debris prevents it from being pulled through the soil or across the soil surface by the subsoiling shanks  4 , thereby helping to preserve the integrity of the topsoil or other soil stratum. Prior to lifting the subsoiler  4  from the soil, it is desirable to retreat the boom a short distance; then uncurl and rotate the tips away from the subsoiling work, along the previously subsoiled path so that the wing tips  17  are raised through soil that is already fractured. This avoids catching the tips  17  on rocks and other firmly entrenched objects that would tend to result in breakage of the tips  17  and helps prevent soil displacement and mixing.  
         [0036]     If it is desired to disperse organic matter over the subsoiled area, then the opposing shank  4  and excavator thumb  8  are pivoted into an operable position for grabbing debris, which is then lifted and dropped over the area. During employment of the mower  2 , the subsoiling shanks  4  are oriented in an idle position. Both the subsoiling and mowing can be conducted through the normal range of operation of the excavator boom  7 . After treatment of an area within reach of the implement is complete, the piece of heavy equipment is retreated, that is, moved in a direction opposite from the area just treated.  
         [0037]     The masticator/subsoiler implement of this invention may be used with any make of excavator, optimally one that is greater than 43,000 pounds and up to about 50,000 pounds gross vehicle weight rating (GVWR) to allow for adequate hydraulic power and excavator ability needed to obtain the full functional capacity.  
         [0038]     The application of this implement can vary from basic mastication/mower needs without subsoiling to full obliteration of a road on flat and rolling topography. Other potential uses are to rehabilitate forested environments, timber harvest brush disposal, skid trail and temporary logging road decommissioning, treatment of small and large scale acreage legacy compaction associated with prior timber harvest and land management activities, wildland fire dozer line rehabilitation, BAER (Burned Area Emergency Response) projects, and general subsoiling of compacted harvest units with no mowing. The same application could be applied to wetland restoration or creation done to mitigate wetland losses in areas under land development. It is estimated that 2-4 acres could be mowed and subsoiled in a day, which is approximately equivalent the acreage that can be mowed in one day using existing equipment.  
         [0039]     The implement of the invention will allow a combination of the following forest management objectives into one project:  
         [0040]     1. fuel reduction (harvest and natural), reducing ground and ladder fuels;  
         [0041]     2. wildlife forage enhancement, reduction of brush promotes new shoots on brush and grasses in winter range allocations;  
         [0042]     3. pre-commercial thinning/brush release, mowing to remove excess trees or to release trees slated for retention from surrounding brush;  
         [0043]     4. reforestation site preparation, subsoiling of compacted temporary logging roads (i.e. skid road, loader road, forwarder road);  
         [0044]     5. creation of effective ground cover for reforestation microsite conditions from mowed vegetation;  
         [0045]     6. soil restoration (specific to hydrology and/or soil productivity) of legacy compaction within previously harvested plantations.  
         [0046]     Examples of situation in which this invention can be used are:  
         [0047]     1. To remove brush and release planted tree stock in plantations where planted stock is in competition with brush;  
         [0048]     2. In plantations in need of pre-commercial thinning; optimum situation is in a forested stand with low species diversity;  
         [0049]     3. In plantations or natural openings, designated as big game winter range, for trimming forage to enhance growth or for mowing decedent branches, which allows new branching to take place;  
         [0050]     4. For reducing fuel loads before prescribed fire to create a break in ladder fuels, thereby promoting a safe ignition of prescribed fuel treatments; and  
         [0051]     5. Restoring unregulated/unmanaged OHV trail access routes.  
         [0052]     All references disclosed herein or relied upon in whole or in part in the description of the invention are incorporated by reference.