Abstract:
A biodegradable skeet or trap target with a body composed principally of a composted waste material comprising sewage sludge, composted animal manure, and/or composted plant matter suitable for fertilizing plants, encapsulated within a substantially rigid, frangible matrix formed of a degradable binder material, is provided by the invention. The body of the target may also comprise a generally inert granular filler material, preferably sand. As an alternative to or in addition to the preferred composted waste material, prepared plant fertilizer may be used as the principal material in the composition of the target. A method of making a biodegradable target with plant nutrients is also provided.

Description:
RELATED APPLICATION DATA  
       [0001]    This application claims the benefit of U.S. provisional patent application serial No. 60/249,906, filed Nov. 20, 2000 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention generally relates to targets for trap and skeet shooting, and in its preferred embodiments more specifically relates to completely biodegradable targets that are non-toxic and that are composed of materials which provide nutrients for plants.  
         BACKGROUND OF THE INVENTION  
         [0003]    Shooting sports such as trap and skeet shooting are very popular, and the number of ranges at which these sports are practiced is significant. The number of targets used each year for trap and skeet shooting is very large. Traditionally, skeet targets have been constructed of clay or a similar material, using pitches, tars, and other petroleum derivatives as binders. These binder materials are toxic to animals and plants, and create environmental hazards as the result of leaching into the soil and potentially contaminating surface water and ground water sources. In addition, targets of the traditional construction are not readily degradable, and expended targets and shards of broken targets accumulated on the ground until they were removed and disposed of. In more recent years, various other approaches have been used to construct skeet targets in an effort to alleviate the problems associated with the traditional construction.  
           [0004]    In one approach, illustrated by U.S. Pat. No. 4,271,118, a target construction without the toxic pitches and/or petroleum derivatives as binders was introduced. The &#39;118 patent discloses a target comprising plaster, and optionally chalk, fly ash and/or heavy spar, with non-toxic binders and other additives. The primary improvement associated with the &#39;118 patent is the omission of actively toxic constituents.  
           [0005]    U.S. Pat. No. 5,788,243 discloses an example of a biodegradable target, composed of cellulose wood flour, surfactant, and an organic binder such as a urea binder. In a somewhat similar approach, U.S. Pat. No. 5,389,142 discloses a composition for a biodegradable clay target. The target disclosed by the &#39;142 patent is composed of clay with a binder consisting of sodium silicate, with or without dextrin. The &#39;142 patent also discloses the incidental inclusion of a small amount, less than one percent by weight, of a mixture of plants seeds and fertilizer pellets. The seeds and fertilizer pellets are not combined within the structure of the target, but, if used, are adhered to a portion of the surface after the target is formed. Although the optional inclusion of a small quantity of seeds and fertilizer pellets as disclosed by the &#39;142 patent represents an increasingly environmentally friendly philosophy, the inclusion of seeds and fertilizer to encourage their growth is not necessarily desirable. If the seeds do germinate and grow, the species of plant may not be desirable to shooting range operators, especially if the seeds and resulting plant growth is not well dispersed but produces clumps or patches of growth. Further, inorganic fertilizers may be toxic to birds and small animals, and the adhesion of seeds and fertilizer pellets may encourage consumption by foraging birds and animals of the fertilizer pellets along with the seeds.  
           [0006]    Another approach to a biodegradable target is illustrated by U.S. Pat. No. 5,467,998, which discloses a composition including flour and a granular edible constituent such as birdseed or grain. An edible and biodegradable polymer is also disclosed as an optional filler. The &#39;998 patent does not disclose the inclusion of any form of fertilizer. In the target disclosed by the &#39;998 patent, the edible constituent comprises approximately two thirds of the volume of the target. U.S. Pat. No. 5,174,581 discloses a target composed of a granular edible constituent such as birdseed, legumes, or oatmeal, in a matrix of crystalized sugar. The edible constituent is disclosed to comprise approximately one half the volume of the target. One of the purposes of the prior art targets comprising a substantial portion of birdseed and other edible materials is to feed, and therefore attract, birds and other wildlife. Since the number of targets used at a shooting range can be large, the amount of food available from such targets is potentially also large. The availability of such a concentrated food source can be expected to attract large numbers of birds and other wildlife to the shooting area. The concentration of, especially, birds on and around a shooting range is not desirable. Large numbers of flying birds create a significant distraction to a shooter trying to visually follow a flying target. In addition, the presence of birds either disrupts activity on the range if the shooters withhold firing to avoid hitting birds, or results in the wounding and killing of birds if the shooters do not withhold. To the extent that seeds comprising the targets remain viable after the process of making the targets, uneaten seeds may germinate and create undesirable plant growth, increasing the maintenance requirements for the operator of the shooting range.  
           [0007]    There remains a need for a skeet target that overcomes the problems and disadvantages of not only the traditional targets, but also the disadvantages and problems associated with other targets known in the prior art.  
         SUMMARY OF THE INVENTION  
         [0008]    It is among the objects of the present invention to provide a skeet target that is free of any materials that are toxic to animal or plant life, or in any way detrimental to the environment.  
           [0009]    It is further among the objects of the invention to provide such a skeet target that is biodegradable and comprises organic materials that are beneficial to plants and soil, and to the environment in general, but that will not attract birds and other wildlife in undesirable numbers.  
           [0010]    It is still further among the objects of the invention to provide such a skeet target that beneficially utilizes materials commonly considered to be and disposed of as waste.  
           [0011]    The present invention provides a skeet and trap target that is wholly biodegradable and that will, upon decomposition, fertilize and condition the soil and existing plants where the target or broken pieces thereof fall. The target of the invention comprises principally an organic fertilizing and conditioning component, mixed with a filler material, preferably sand, and a liquid binder which will cure to form a matrix encapsulating the fertilizer and filler. The target is formed into a generally conventional saucer shape in a form or mold. The target has sufficient strength and rigidity to withstand the forces imposed by a mechanical target throwing apparatus, but is easily breakable by the impact of shot from a shotgun blast. The target is formed with an aerodynamic shape, and with a size and weight so that when thrown it will exhibit essentially the same type of flight pattern as a conventional clay target, making the target suitable for use in both recreational and competitive shooting.  
           [0012]    In the preferred embodiment of the invention the principal material from which the target is formed comprises a thoroughly dried composted waste material, such as sewage sludge, composted animal manure, or a mixture of the two. The material is effectively sterilized by the drying process, or by other sterilization means, and is mixed with sharp sand or other suitable filler material. The dry ingredients are then mixed with a sufficient quantity of binder material, in liquid form, to achieve a workable consistency, generally as a thick slurry or dough-like mass. The slurry is placed in a mold or form and compacted into the desired configuration for the target. The binder is allowed to cure sufficiently for the targets to be removed from the mold or form, and the curing process is completed. After the targets are removed from the mold or form, they may be sprayed on one or both sides with a non-toxic, preferably water soluble colorant, such as a food coloring, in any desired color. The colorant may be mixed with the material prior to forming the targets, but the application of a light surface coating is preferred.  
           [0013]    The composition of the target of the invention is susceptible to a number of variations in composition within the scope of the object of providing beneficial nutrients to plants and to the soil. As an alternative to the preferred sewage sludge and/or composted animal manure, or as an additional constituent therewith, the target of the invention may comprise composted plant matter, including but not limited to yard wastes, seed or grain hulls, agricultural wastes, and the like. These materials are typically disposed of as waste, but when used in the production of the target of the invention are put to a commercially productive use and then returned to the environment in a beneficial manner. Pelletized or granulated fertilizer, preferably slow-release and more preferably also of wholly organic composition, may be utilized as well. Other soil additives and/or conditioners, such as enzymes or algae in inactive form, could be added in appropriate quantities to the primary materials during the production process, if desired.  
           [0014]    In the preferred embodiment the binder comprises a mixed silicate based liquid and liquid catalyst, which cures to produce a sodium silicate matrix encapsulating the dry components of the target. The cured sodium silicate structure is rigid and hard, but readily breakable upon impact as when struck by shot from a shotgun. It should be understood, however, that other binder materials, such as a biodegradable polymer or even a sugar-based material, could be used within the scope of the invention, so long as they are of suitable characteristics to achieve the objects of the invention.  
           [0015]    When the binder is mixed with the dry component of the target to form a moldable slurry, the binder fully permeates and surrounds the dry material such that when the binder cures it forms a matrix in which the dry components are encapsulated. The resulting structure holds its shape well when dry, and is of sufficient strength to readily withstand storage and handling without disintegration. The target will also withstand the acceleration force imposed by a mechanical throwing apparatus without breaking. The structure is, however, relatively brittle, so that it will break apart into fragments when struck by shot fired from a shotgun. When the fragments, or whole targets if missed by a shooter and not retrieved, become wet from rain or irrigation water from sprinklers the cohesive structure of the target disintegrates, the constituent material is released to the soil, increasing its organic matter content, and the nutrients contained in it are available to plants. The nutrients contained in the material of construction of the target are present in relatively low concentrations as compared to inorganic fertilizers, for example, and are released slowly into the soil, eliminating the possibility of fertilizer burn. The slow release of nutrients also avoids problems with high nutrient concentrations in runoff water and prevents nutrient pollution of surface and ground water resources.  
           [0016]    Sharp sand is preferred for use as a filler material in the composition of the target of the invention, and is advantageous for several reasons. It is desirable to produce a target that is generally equivalent to a conventional target in dimensions and weight, and since sand has a higher density than the composted waste material it allows weight to be adjusted without significant changes in dimension. In addition, sand, unlike clay or flour, for example, which are cohesive and resist dispersion even when wet, exhibits no cohesion when released from the binder, and facilitates disintegration and dispersal of the target material in the environment. Sand is also a natural constituent of soil and does not adversely affect soil composition.  
           [0017]    The materials of construction of the target of the invention are not a food source for birds or other animals and will not attract birds and other animals to the shooting range, thereby eliminating the problem associated with target compositions containing birdseed and/or other food sources. However, the materials are non-toxic, and if fragments or targets are eaten by birds or other wildlife the materials will cause no harm to them. In addition to providing soil and plant nutrients, the materials of construction of the target of the invention may also provide nutrients for earthworms and other beneficial soil organisms, and thus further benefit the soil ecology. The materials of construction also function as soil conditioners, actually improving the structure of the soil. 
       
    
    
       [0018]    The structure and composition of the target and its features and advantages will be disclosed in more detail below, with reference to the accompanying drawing figures.  
       BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a top plan view of the preferred embodiment of the target of the invention.  
         [0020]    [0020]FIG. 2 is a sectioned side view of the preferred embodiment of the target of the invention, along line  2 - 2  of FIG. 1.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]    Referring to the drawing figures, the preferred embodiment of the target of the invention, generally identified by reference numeral  10 , is configured in a domed saucer-like shape with a relatively thin body  11 . Both the outer, convex, surface and the inner, concave, surface of body  10  are formed with a plurality of ridges  12  for the purpose of enhancing the aerodynamic stability of the body when it is thrown into the air by a throwing apparatus. The specific configuration of the target is not greatly material to the invention, and it should be understood that a variety of configurations may be utilized.  
         [0022]    In the preferred embodiment of the invention, the principal component of the body of the target is a composted organic waste material that contains nutrients utilized by plants in their development and growth, and thus performs as a fertilizer when applied to the soil. In the context of this description, the term composted generally has its commonly understood meaning of decomposed or digested. Such composted organic waste material also functions as a soil conditioner, by adding organic material to soil to which it is applied. It is particularly preferred that such material include nitrogen compounds, phosphorous compounds, and potassium compounds. However, the absence of one or even all of these plant nutrient compounds does not necessarily render a composted organic material unsuitable for use, since such a material may still provide soil conditioning benefits.  
         [0023]    A wide variety of such materials may be utilized in the construction of the target of the invention. A particularly preferred material is dried sewage sludge, from, e.g., municipal wastewater treatment plants, which has been thoroughly composted or digested in the course of the treatment process, and dried to remove excess moisture. The sludge may also, in the course of preparing it for use as a raw material for use to make targets, be sterilized by heating or other means consistent with use of the sludge as a fertilizer. Reasonable care should be exercised in selecting sludge for use as a raw material to avoid sludge containing undesirable materials such as heavy metals, viable disease organisms, and the like. In addition to or instead of sewage sludge, somewhat similar materials, such as composted animal manures, are also very suitable for use in the construction of the targets of the invention. Well composted materials from such sources are not obnoxious in nature, and are well suited for the contemplated use.  
         [0024]    Composted organic waste materials from other sources, such as almost any type of plant derived material, may also be used in the construction of the targets of the invention. Non-limiting examples of such materials include composted leaves, stems, seed hulls, grain hulls, and even tree bark and other wood wastes. In general, it is preferred that the principal material or materials selected for construction of targets in accordance with the invention include components useful as fertilizer for plants and/or as a conditioner for soil, and that such material or materials be of the nature of waste.  
         [0025]    In the preferred embodiment of the invention, sharp sand is mixed with the organic material as a filler. Although other granular filler materials could be used within the scope of the invention, sharp sand is preferred because it is not cohesive and is readily dispersed when the target degrades, and because sand is a natural constituent of soils. The sand filler serves to separate the more fibrous waste material and reduce any tendency to agglomerate or clump, and facilitates degradation of the target and dispersal of the fertilizer material over the soil. Because the sand is relative dense in comparison to the dry density of the composted waste fertilizer material, it also allows the weight of the target of the invention to be adjusted to closely match the weight of conventionally constructed targets while maintaining the desired target dimensions. In the preferred embodiment, using sewage sludge as the fertilizer material, the relative proportions of fertilizer material and sand are generally ten parts fertilizer material to three parts sand, by weight.  
         [0026]    Although the benefits of the particularly preferred embodiment of the invention include the productive utilization of wastes and the inclusion of organic matter for soil conditioning, the scope of the invention also encompasses the use of commercial fertilizers as the primary material of construction of the body of the target. In this context, organic fertilizer is preferred, but inorganic fertilizer could be used as well. It is desirable for the plant nutrients to be released from the material relatively slowly, as from composted wastes or organic fertilizers, rather than rapidly, as from water soluble inorganic fertilizers, so as to avoid “burning” plants and creating pollution problems. Many granular commercial fertilizers are prepared with a filler material already incorporated into the product, and are typically of higher density than the density of dried composted waste material. Many commercial fertilizers are also prepared to resist clumping, so the addition of filler material may not required for targets constructed with commercially prepared fertilizer. It should be understood that filler may be added as needed to achieve the desired physical characteristics of the target of the invention.  
         [0027]    Although not necessary to the benefits for plants and soil provided by the invention, the principal material of construction may be enhanced with nutritional additives, such as trace minerals, enzymes, soil algae, and the like, as known and used in the horticultural field.  
         [0028]    To produce the target of the invention, the selected principal material of construction, whether composted waste material or prepared fertilizer or combination thereof, is thoroughly mixed with a liquid or liquified binder material to form a workable slurry of appropriate consistency to be placed in a mold or form to shape the target body. The principal material and the binder are mixed so that the binder thoroughly coats the fibers, particles, granules, as the case may be, of the principal material and forms a fluid web through the resulting slurry. The consistency of the slurry may be varied to accommodate the method used for placing it in the mold or form, as from a thick dough-like consistency to a looser, more pumpable slurry.  
         [0029]    The preferred binder material for use in the construction of the target of the invention is a silicate based, catalytically curing binder, such as the product commercially available from J. B. DeVenne, Inc., identified as “Binder  1 ”. The base material and the catalyst are initially in liquid form with a viscosity suitable for thorough mixing with and coating of the dry components to produce a cohesive mass having a dough-like consistency. The binder cures to produce a hard, but brittle, sodium silicate matrix surrounding and encapsulating the dry components. The resulting structure is of sufficient strength to withstand handling and the stresses imposed by mechanical throwing apparatus, but will break into fragments when struck by shot fired from a shotgun. The preferred binder material is readily water soluble and will quickly degrade when exposed to the elements to release the other components of the target from the matrix and allow them to disperse. With the preferred composition of the target of the invention, the binder material is used in the general proportion of about four parts binder by weight, to the ten parts fertilizer material and three parts sand referred to above.  
         [0030]    Although a preferred binder material has been described, it is to be understood that the scope of the invention is not limited to the preferred binder, and any binder material with suitable characteristics may be used. The binder selected for use should be non-toxic to plant and animal life and benign to the environment. The binder must be liquefiable, and cure or dry to a rigid but frangible state, so as to impart sufficient strength to the target to maintain its structural integrity when thrown from a mechanical throwing device, but allow the target to fragment when struck by shot fired from a shotgun. The binder material should also re-liquify or dissolve in water, so as to allow the target body or fragments thereof to disintegrate when exposed to the elements. Suitable alternative binders include, without limitation, other silicate based binders and biodegradable polymers. A sugar-based could be used, but is not considered desirable because of the propensity to attract animals and encourage consumption of fragments and targets.  
         [0031]    The prepared slurry of the principal material, filler (if used) and liquified binder is placed in a mold or form to shape the desired target body configuration, and allowed to cure or dry in the mold or form until the target body has achieved sufficient integrity for it to be removed without deforming or disintegrating. In the preparation of the preferred embodiment, pressure up to about 50,000 pounds per square inch is applied to assure the integrity of the completed target body structure. If appropriate, depending on the binder material used and/or to reduce the curing or drying time, heat may be applied to the mold or form. The partially cured or dried target is removed from the mold or form and set aside to complete the curing or drying process. The completed targets may then be packaged in preparation for shipment and use.  
         [0032]    If desired, a coloring agent may be applied to the outer surface of the body after it is removed from the mold or form, for the purpose of making the target more visible to a shooter. It is preferred that any coloring agent used be non-toxic and environmentally benign. A preferred coloring is tempera paint, which is completely non-toxic and environmentally benign. Various readily available food colorings are also suitable. As an alternative to surface application, the coloring agent may be added to the slurry before the target body is formed, so that the color extends through the body of the target.  
         [0033]    The foregoing description of the preferred and alternative embodiments of the invention is intended to be illustrative and not limiting. It is to be understood that further alternatives, variations, and equivalents may be utilized, all within the scope of the invention as claimed.