Abstract:
A system of poisonous bait presentation that preserves and prolongs the original characteristics of a deployed point source bait supply until such time as targeted pests expose a portion of the bait. The aggregate bait supply is distributed among separate compartments positioned proximately within a bait container produced from a deformable material that is resistant to reaction with the intended bait content and degradation from exposure to the environment once deployed. Palatability of the material may be enhanced by the inclusion of a feeding stimulant and/or attractant throughout it or in or on portions of it, thereby encouraging targeted pests to investigate it and, through piercing or mastication, eventually breach and make available for consumption one or more compartments of the preserved bait.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/120,172, filed Feb. 16, 1999. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of devices for holding poisonous material, adapted to attract and kill vermin, particularly insects. More particularly, the invention relates to a practical, safe, and maintenance free system for preserving the integrity of a deployed point source bait supply until such time as a portion of the bait supply is exposed through the activity of targeted pests and thereby made available for consumption. 
     2. Description of the Prior Art 
     Formulation is the processing of a technical grade pesticidal compound by any method that will improve its properties of storage, handling, application, effectiveness, or safety. A low level of pesticide incorporated into one or more materials including food that is relished by the targeted pest is considered to be a bait formulation. Baits are typically manufactured in solid, semisolid, or liquid form and, with the exception of powdered or particulate baits which are typically broadcast over large areas, most baits are intended for point source deployment at selected locations where targeted pests are likely to encounter them and exposure to nontarget organisms is minimized. Baits are typically deployed in a manner that facilitates targeted pests with instant access to them, thereby exposing one or more components of the bait to degradation from environmental influences. Consequentially, baits deployed as a preventive measure and the remainder of baits deployed to combat active infestations become increasingly less effective over time and may serve as a food supply for the target pest or other pests if not removed when the pesticide becomes ineffective. 
     The art is aware of rodenticide baits that have been contrived to include a means for protecting the bait from environmental degradation until breached by the targeted pest. Examples are disclosed in L&#39;Institut Pasteur, FR. Pat. No. 2,032,164, Giroud-Abel, U.S. Pat. No. 3,032,915, Arbaugh, U.S. Pat. No. 3,624,198, Burke et al., U.S. Pat. No. 3,906,656, and Sherman, U.S. Pat. No. 4,891,218; however, these examples are not concerned with dispensing liquid bait and do not target insects. 
     Wilson et al, U.S. Pat. No. 4,874,611 discloses a microencapsulated ant bait having a poisoned liquid core and a water resistant polymeric shell which is impervious to the core material. The shell material includes attractants which induce the ants to carry the bait particles back to nest where the microcapsule is penetrated and the core material is ingested. As with other particulate baits, this product is specifically intended for broadcast deployment. 
     The art is generally aware of numerous insect bait stations comprised of a central bait area surrounded by a housing and passageways of various configurations and complexities intended to induce or at least permit the ingress and egress of sufficiently small pests while obstructing access by larger organisms. A number of these devices have been contrived specifically to dispense liquid bait. While these devices do provide protection to nontarget organisms, they lack the means to protect the contained bait supply from environmental degradation because they provide targeted insects with instant access to the liquid bait. 
     Insects have different dietary requirements at different stages of development so an optimum bait deployment system should be capable of simultaneously accommodating a variety of baits containing protein, lipid, or carbohydrate food types. Ants are a major urban pest and because foraging adult ants most easily assimilate liquid food and supply nourishment to non-foraging nest mates, an optimum bait deployment system should be capable of accommodating liquid, solid, or semisolid baits. Urban pest control strategies that are changing from monthly to annual or semiannual treatment schedules and incorporating more point source bait supplies into their insect treatment plans need products that can be deployed as a preventive measure and remain effective for extensive periods. Different pest types such as ants or roaches vary greatly in physical size, population density, and behavior as do different species of the same pest type. Therefore, the basic design of an optimum bait deployment system should be sufficiently versatile to facilitate the use of various materials and scaling of its overall size and capacity to accommodate particular targeted pests. A need exists in the art for a bait dispensing system that incorporates all of the desirable characteristics listed above. 
     BRIEF SUMMARY OF THE INVENTION 
     An important object of the present invention is to provide a point source bait presentation system that can be deployed as a preventive measure and remain effective over an extended time period. More specifically, the aim of the invention is to exploit the inquisitive, resourceful, and destructive behavior of pests by encouraging them to explore and breach a penetrable protective bait container, thereby exposing preserved bait and making it available for consumption. Further, the protective bait container material is enhanced by the addition of an attractant or feeding stimulant to promote its exploration. Still further, the bait container is manufactured to include a plurality of discrete compartments for holding portions of the aggregate bait supply separately, thereby limiting environmental exposure of bait to breached compartments. 
     Another object is to maximize consumption of exposed bait by promoting sequential exposure of bait compartments. This is accomplished by an impenetrable housing that limits access to specific areas of the bait container, thereby motivating pests to consume the content of one compartment before breaching the wall of an adjoining compartment. 
     Another object is to prevent children and pets from being poisoned by exposed bait. This is accomplished by obstructing direct access to the bait container with topographic features incorporated into the impenetrable housing that create a maze-like path which targeted pest can easily navigate to reach the bait container. 
     A further object of the invention is to provide for its deployment at a variety of locations both indoors and outdoors at, below, and above ground level to control crawling, burrowing, and flying insects having mandibulate or piercing mouthparts. It will become obvious from the drawings that the shape, volume, and configuration of bait compartments can be changed and scaled along with the impenetrable housing to suit a particular application without straying from the inventive concept. 
     Yet another object is to facilitate provisioning a single device with different baits for pests, such as ants, with changing dietary requirements and preferences. Protein, carbohydrate, or lipid based baits in solid, semisolid, or liquid form may be added separately to compartments in a single bait container to facilitate the simultaneous presentation of a variety of baits and formulations. 
     Still another object of the invention is to make it easy to use by nonprofessionals. No maintenance is required between deployment and disposal of the device and bait levels can be easily monitored visually through the impenetrable housing which is at least in part transparent. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of the preferred embodiment of the invention. 
     FIG. 2 is a plan view of the assembled preferred embodiment of FIG.  1 . 
     FIG. 3 is an elevation view of the assembled preferred embodiment partially sectioned along section line  3 — 3  of FIG.  2 . 
     FIG. 4 is a plan view of a second embodiment of the invention. 
     FIG. 5 is an elevation view of the second embodiment of the invention shown in FIG.  4 . 
     FIG. 6 is a partial sectional view, as indicated in FIG. 5, of the second embodiment of the invention taken along section line  6 — 6  of FIG. 4, shown in perspective. 
     FIG. 7 depicts an alternative method of producing the second embodiment of the invention in a view comparable to that of FIG.  6 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Two functionally equivalent embodiments of the invention, a preferred in FIGS. 1-3 and a second in FIGS. 4-7, are presented to demonstrate its potential versatility. Reference numbers appearing in this detailed description of the drawings conform to those found in the drawings. Like reference numbers are used to identify like components on subsequent figures. Lower case letters following a reference number are used to identify subcomponents or features that are functionally similar but differ slightly in structure and/or location. 
     As shown by the exploded perspective view of the preferred embodiment of the invention in FIG. 1, the liquid dispensing bait station includes three main components; base  10 , cover  40 , and bait container  50 . Base  10  features a floor  10   a,  walls  12   a-d  that generally conform to the shape of main body  20 , and barricades  14   a-d  that obstruct direct access to the interior area of base  10 . Surfaces  10   d  of walls  12   a-d  and barricades  14   a-d  provide support and areas of attachment for transparent cover  40 . Transparent cover  40  has a rim  40   b  that fits securely against the outer surfaces  10   e  of walls  12   a-d  and barricades  14   a-d.  Rim  40   b  provides additional points of attachment to base  10  as well as further obstructing access to the interior area of base  10 . Bait container  50  includes an upper seal  30  and a main body  20 , featuring an orderly arrangement of entryway compartments  26  adjacent to surfaces  24   a-d  and other interior compartments  26   a,  all manufactured in close proximity. Depending on the method of producing main body  20 , an optional lower seal  20   b  (shown) may be required to close off the bottom surface of the midsection  20   c  of assembled bait container  50 . Upper seal  30  is bonded to the upper surface  20   d  of main body  20  subsequent to filling, thereby isolating compartments  26  and  26   a  from each other and atmospheric influences. 
     FIG. 2 is a plan view of the first and preferred embodiment of the assembled invention showing features identified in FIG. 1 as they would appear when seen through transparent cover  40 . Referring to the lower right corner of FIG. 2, distal outboard surfaces of walls  12   c  and  12   d  and inboard surface of barricade  14   d  define the lateral boundaries of access paths  10   f,  which are curved to guide pests to entrance  10   g  and into foraging area  10   h.  A gap between distal interior surfaces  10   c  of walls  12   c  and  12   d  and surface  24   d  of bait container  50  define the lateral boundaries of foraging area  10   h.  A similar arrangement is repeated at other corners so that a total of four entrances  10   g  and foraging areas  10   h  are provided. A tight fit between bait container  50  and base  10  interior surfaces  10   c  reduces atmospheric exposure of and prohibits pest access to side surfaces  22   a-d  of bait container  50 . Initial access to bait is thereby restricted to side surfaces  24   a-d  of bait container  50 . The contours of barricades  14   a-d  and their position in relation to walls  12   a-d  obstruct direct access to bait container  50  and thereby function to preclude premature rupture of entryway compartments  26  and interior compartments  26   a  from probing by nontarget organisms. 
     FIG. 3 depicts the assembled liquid dispensing bait station of FIG. 2 in elevation view partially sectioned along line  3 — 3  of FIG.  2 . Transparent cover  40  is shown bonded to the upper surfaces  10   d  and outboard lateral surfaces  10   e  of barricade  14   a  and walls  12   c  and  12   d  along the bottom of surface  40   a  and interior surfaces of rim  40   b,  respectively. Walls  12   c  and  12   d  are shown arising from base  10  floor  10   a.  Assembled bait container  50  is shown appressed to floor  10   a  at surface  20   a  of optional lower seal  20   b,  the inner surface  10   c  of wall  12   d  at surface  22   d,  and the bottom of surface  40   a  of cover  40  at surface  30   a  of upper seal  30 . Access to bait container  50  is thus prohibited from above and below by transparent cover  40  and floor  10   a  of base  10 , respectively. 
     Base  10  may be of any suitable material; however, is preferably molded from heat deformable sheet plastic side by side with other bases  10 , thus facilitating simultaneous manufacture, assembly, and packaging of multiple units fixed in an array. Perforations or scoring should be added between bases  10  to allow for easy separation of individual units along base  10  side surfaces  10   b.  The overall size of base  10  and the relative spacing between walls  12   a-d  and barricades  14   a-d  should be varied and adjusted to conform to and accommodate or exclude specific pests or groups of pests and intended deployment locations. 
     Main body  20  is produced from any suitable material such as, for example, paraffin wax that is pliable through mastication, piercing, or probing by targeted pests, yet resistant to reaction with the intended bait content and degradation from exposure to the environment once deployed. An attractant or feeding stimulant such as powdered sugar may be combined with the material of main body  20 , portions of it, or portions of its surfaces, such as  24   a-d,  to encourage targeted pests to feed on or damage those areas, thereby exposing the bait-filled compartments within. An arrangement of compartments  26  and  26   a  are formed throughout the main body  20  either by machining, molding, or stamping so that they are in close proximity and do not penetrate the bottom surface  20   a  of main body  20 . The final shape, volume, number, and arrangement of compartments can and should be tailored to conform to physical and, behavioral characteristics of the specific targeted pests or groups of pests. Optionally as shown in FIGS. 1 and 3, the main body  20  may be constructed from two separate parts; midsection  20   c  may be cut from an extrusion and closed off with lower seal  20   b  made of a similar material. Compartments should be arranged and separated by a wall that is sufficiently thin to permit easy access to adjoining compartments without compromising the structural integrity of bait container  50 . Bait, if not already a contrasting color, should be dyed or colored as with blue food coloring before filling main body  20  compartments  26  and  26   a  with it. Compartments  26  and  26   a  are then hermitically sealed and isolated with upper seal  30 , also made of a similar material. Seals  20   b  and  30  need not be impregnated with an attractant or feeding stimulant and may be bonded to midsection  20   c  with heat. Upper seal  30  should be sufficiently thin to facilitate the transmission of enough light through it to distinguish full and empty compartments  26  and  26   a.  The final lateral size and contour of bait container  50  should equal that of surfaces  10   c  of walls  12   a-d  except at its side surfaces  24   a-d  where, following insertion of bait container  50  into base  10 , an open foraging area  10   h  would result. The boundaries of the foraging area should be varied and adjusted to conform to and accommodate or exclude specific pests or groups of pests. Thickness of the wall between surfaces  24   a-d  and entryway compartments  26  should be minimized to permit easy access to bait compartments without compromising the structural integrity or the bait preserving characteristics of bait container  50 . 
     Cover  40  is preferably molded or formed of rigid transparent plastic to facilitate visual inspection of bait consumption from bait container  50 . Inside dimensions of cover  40  should closely conform to the shape and size of upper  10   d  and outer  10   e  surfaces of walls  12   a-d  and barricades  14   a-d  as seen in FIGS. 2 and 3. Following insertion of bait container  50  into base  10 , cover  40  is permanently affixed to base  10  by adhesive or other suitable means. Floor  10   a  and the lower edge of rim  40   b  define the lower and upper boundaries, respectively, of the entrances to access paths  10   f.  The height of rim  40   b  should be varied and adjusted to conform to and accommodate or exclude specific pests or groups of pests. 
     In general, the preferred embodiment of the liquid dispensing bait station described above is placed on or affixed to either horizontal or vertical surfaces in proximity to areas where targeted pests are likely to encounter it. Upon discovery, pests are encouraged by the structure and arrangement of walls  12   a-d  and barricades  14   a-d  to enter one of four foraging areas  10   h.  Initially, pests are encouraged by the presence of a feeding stimulant or attractant to feed on or pierce one of surfaces  24   a-d  and penetrate an entryway compartment  26 , exposing its bait content. Subsequent to the exposure of an entryway compartment  26 , pests arriving later are additionally encouraged by residue from exposed bait to penetrate adjoining entryway compartments  26  and interior compartments  26   a.  Other compartments remain intact offering preserved bait to other pests that arrive months later. The transparent cover  40  and translucent quality of wax seal  30  allow for visual inspection of foraging activity acknowledged by the disappearance of bait that is preferably colored or dyed a contrasting color. When all or the majority of bait is consumed, the entire device may be discarded and replaced. Several devices, dependent upon the application and area to be covered, should be deployed. 
     An alternative and second embodiment of the invention is shown in plan and elevation views in FIGS. 4 and 5, respectively. FIG. 6 is a partial view of the second embodiment of the liquid dispensing bait station, as indicated by dashed circle  6  in FIG. 5, shown in perspective sectioned along line  6 — 6  of FIG.  4 . Referring to FIGS. 4-6, three main components are identified; housing  110 , bait container  150 , and end plug  140 . Housing  110  is a transparent cylinder with an inner diameter generally conforming to the outer diameter of bait container  150 . Bait container  150  features a linear arrangement of bait filled compartments  156  and  156   a,  each manufactured in close proximity and completely isolated. End plug  140 , of which two are required, resembles a short section of the threaded portion of a male screw. End plug  140  features a spiral ramp  140   c  with an outer diameter slightly larger than the inner diameter of housing  110 , supported centrally by a small constant diameter cylindrical shaft  140   e  and peripherally by two semicircular shafts positioned one-hundred eighty degrees apart relative to the central shaft  140   e.  FIG. 6 demonstrates that access to entryway compartments  156  and interior compartments  156   a  from ends of bait container  150  is limited to organisms that are small enough to navigate the spiral tunnel created by the insertion of end plug  140  into housing  110 . Access to bait through side surface  152  is prohibited by housing  110 , which also provides protection from environmental influences to bait container  150 . 
     Housing  110  may be of any suitable material; however, is preferably cut from rigid transparent plastic tubing to a length slightly longer than that of the desired bait container  150 , thus accommodating the insertion of end plugs  140 . End plug  140  may be of any suitable material; however, is preferably molded of rigid plastic by injection into a two-part mold split at peripheral support shafts  140   d.  The mold should accommodate production of a substantial length of stock from which numerous end plugs  140  could be cut. The outer diameter of end plug  140  should be slightly larger than the inner diameter of housing  110 . Upon insertion, the forced fit would slightly deform end plug  140  causing it to resist twisting and removal, thereby reducing the risk of exposure of bait to nontarget organisms. 
     Bait container  150  is produced from any suitable material such as, for example, paraffin wax that is pliable through mastication, piercing, or probing by targeted pests, yet resistant to reaction with the intended bait content and degradation from exposure to the environment once deployed. An attractant or feeding stimulant such as powdered sugar may be combined with the material, portions of it, or portions of its surfaces such as  154 , to encourage targeted pests to feed on or damage those areas, thereby exposing the bait-filled compartments within. Bait container  150  may be produced and filled simultaneously by extrusion through a multiport die. Intermittent injection of bait through the center of the multiport die during the constant injection of the bait container  150  material would produce a continuous cylindrically shaped extrusion supporting the bait filled compartments  156  and  156   a.  The outer diameter surface  152  of bait container  150  should approximate the inner diameter of housing  110  and facilitate its insertion into housing  110 . The length of bait container  150 , the volume of individual compartments  156  and  156   a,  and the thickness of dividing walls at surfaces  154  and  154   a  can and should be varied to conform to the physical and behavioral characteristics of specific targeted pests or groups of pests, as well as the intended placement of a device. By varying these parameters the device could take on an infinite number of sizes; however, a limited number of standard diameter bait containers  150  and end plugs  140  could be used with various standard lengths of corresponding standard diameter housings  110  to produce devices in a finite number of standard sizes. 
     In a view identical to that of FIG. 6, FIG. 7 depicts the result of an alternative method of producing the second embodiment of the device shown in FIGS. 4-6. Bait compartments  156  and  156   a  are produced inside housing  110  by alternating the injection of bait and a suitable protective material, such as paraffin wax, into housing  110 . Bait compartments are isolated by a layer of the material which is sealed against housing  110  at surfaces  158 . 
     In general, the second embodiment of the liquid dispensing bait station described above is placed on or affixed to either horizontal or vertical surfaces in proximity to areas where targeted pests are likely to encounter it. Owing to its shape and variety of possible sizes, it is ideally suited to inconspicuous placement in areas between carpeting and baseboards, in electrical outlet and switch boxes, and in wall voids where it might be suspended by a string or holder (not shown). Upon discovery and exploration, pests are encouraged by the structure of end caps  140  to enter housing  110  and initially encounter surface  154  of bait container  150 . The presence of a feeding stimulant or attractant would induce the pests to feed on or pierce end surface  154  and eventually penetrate an entryway compartment  156 , exposing its fresh bait content. Subsequent to the exposure of an entryway compartment  156 , pests arriving later are additionally encouraged by residue from exposed bait to penetrate adjoining interior compartments  156   a.  Other interior compartments  156   a  remain intact offering preserved bait to other pests that arrive months later. The transparent housing  110  and translucent quality of wax bait container  150  allow for visual inspection of foraging activity acknowledged by the disappearance of bait that is preferably colored or dyed a contrasting color. When all or the majority of bait is consumed, the entire device may be discarded and replaced. Several devices, dependent upon the application and area to be covered, should be deployed. 
     The use of baits to present pesticide to targeted organisms is well known to those experienced in the field of pest control and has well-established residential, commercial, and agricultural value world-wide. A practical means of manufacture and use is described above for two embodiments of the invention which can be varied in proportions and size to accommodate both deployment at various locations under various conditions and a variety of pests. While there has been described preferred embodiments of the invention, it should be apparent to those skilled in the art that numerous alterations, omissions, and additions to their design can be made without departing from the spirit of the invention. While there has also been described practical means of manufacturing and using the preferred embodiments of the invention, it should be equally apparent to those skilled in the art that improvements in manufacturing techniques, the inclusion of additional uses, and alternative methods of deploying the invention may be realized and implemented, also without departing from the spirit of the invention. 
     For example, the protective housings and safety features may be less elaborate or not necessary in applications where exposure to nontarget organisms is not a consideration, such as deployment at subterranean, agricultural, or inaccessible locations. At an extreme, the invention could be manufactured and sold to qualified pest control technicians as a large slab or block which would then be divided and deployed as they see fit. While this would result in the loss of the important feature of sequential exposure of bait compartments, any decrease in efficiency may be offset by a lower cost of obtaining and deploying the invention in this manner. 
     The invention could also be sold as standard components without assembly to qualified pest control technicians, allowing the device to be configured for a specific application. This might include selecting a bait or combination of baits that they feel will work best and inserting the bait(s) into the bait container. This might also include tailoring the diameter and length of the second embodiment of the invention to fit a particular location. 
     A means of rupturing one or more bait compartments may be provided for applications or circumstances where the initial activation of the device at the time of deployment is prudent. 
     The bait container might be constructed of an opaque material if ease of manufacturing or improvements to its preserving or attractive qualities outweigh the benefit of visually monitoring the bait supply through a thin layer of translucent material, such as paraffin wax. 
     The generally flat arrangement of compartments in FIGS. 1-3 could be combined with the linear arrangement of compartments in FIGS. 4-7 to produce a bait container with adjoining layers, of numerous compartments. 
     The invention is also well suited to dispensing nonpoisonous nutritious food to pets and laboratory reared animals, such as insects, and could be deployed without safety features and possibly without the benefit of sequential exposure of compartments facilitated by inclusion of a protective housing. 
     A bait container resembling that of the first embodiment of the invention might also be formed around the bait in a single step. This may be accomplished in a number of ways depending on the proposed bait content. For example, liquid or semisolid baits could be injected into the liquid phase of the bait container material, as demonstrated for the second embodiment of the invention. The liquid phase of the bait container material could also be added to solid baits that are preformed and prearranged in accordance with the desired bait compartment size, shape, and distribution pattern, or vice-versa. This procedure could also be applied to liquid or semisolid baits if their phase is temporarily altered to the solid state or if they are supported by a porous or fibrous material, also preformed in accordance with the desired bait compartment size and shape.