Abstract:
A rodent bait station has a base with a hinged cover which is lockable to the base to define an interior volume which receives a ballast weight of three to twenty-four pounds which biases a floor of the base against a support surface. At least one rodent access opening in the bait station allows a rodent to pass in to the interior volume. A bait or a rodent trap is positioned within the interior volume such that a rodent can move freely within the interior volume so as to access the bait or rodent trap.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 13/052,249, filed Mar. 21, 2011, which issued as U.S. Pat. No. 8,793,929, on Aug. 5, 2014, the disclosure of which is incorporated by reference herein. 
    
    
     STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to bait stations containing rodenticide bait or traps in general and to bait stations in combination with a ballast weight in particular. 
     Bait stations serve two general purposes, the first is to shield the bait or traps from non-target species and people, particularly children, and the second is to facilitate monitoring rodent presence in a particular area, by preventing targeted rodents from removing the bait. The bait station generally consists of a lockable plastic or metal container in which bait or traps are placed. If bait is used, it is often in the form of bait blocks, which are formed of grain mixed with paraffin and rodenticide. The bait blocks are cast or extruded and their use facilitates retaining the bait within the bait station to prevent the targeted rodents from scattering the bait. 
     To prevent movement of the bait station by a targeted or non-targeted species, a bait station is often screwed or nailed to the floor or other structure. This approach has its limitations. Using fasteners to attach the station may damage the building floor. Moreover, when the bait station is screwed down it is difficult to clean (typically done by inverting it), and the approach is less easily done where the floor is concrete or the like, or where the bait station is outdoors where a ground anchor is necessary. In these situation, instead of attaching the bait station to a fixed object the bait station may be attached to a ballast weight. Any substantial weight attached to the bait station prevents the targeted species from easily removing the bait or traps from their initial position and generally reduces the interest of pets and even children in playing with the bait station, because the added weight means it takes more effort to move or manipulate the bait station. Attachment of weight to a bait station generally requires an additional structure mounted beneath the bait station. 
     SUMMARY OF THE INVENTION 
     The bait station of this invention comprises a bait station base connected by an integral hinge to a cover. Closing the cover against the base locks it to the base. The bait station cover and base define an interior volume, in which is placed rodenticide bait or rodent traps. The base has portions forming a floor and an upwardly extending side wall which defines two rodent access openings. The cover likewise has portions defining an upper wall and downwardly depending side walls which engage the upwardly extending side walls of the base. Placed within the base is a ballast weight of approximately 7.5 to 8.5 pounds with a specific gravity of about 2.3, typically of brick or concrete, with a volume of about 85 cubic inches. Placed on top of the ballast weight is a tray which supports rodent traps or a plurality of bait blocks mounted to the tray or between the tray and the upper wall of the cover. Portions of the bait station base form ramps which extend upwardly from the floor of the base adjacent the rodent opening. The ramps extend upwardly to a landing formed as an extension of the tray, wherein the ballast extends between the ramps and below the landing. The landing leads to the rodent trap or the bait contained on the tray proper. 
     From the landing an entryway into the tray proper is defined between baffles extending downward from the cover and portions of the tray which extend upwardly. The upwardly extending portions of the tray and the downwardly extending portions of the tray directly engage so that when the cover, to which the downward extending portions are integral, is closed, the cover clamps the tray in place and prevents movement of the underlying ballast weight. Smaller downwardly extending flanges which extend outwardly of the cover side walls engage portions of the tray landing and similar downwardly extending flanges engage portions of the tray opposite the landing and adjacent to the cover side wall, to prevent movement of the tray and thus movement of the underlying ballast weight during shipping. 
     It is an object of the present invention provide a bait station with an internal ballast. 
     It is another object of the present invention to provide a bait station which can easily be cleaned out. 
     It is a further object of the present invention to provide a bait station which prevents an internal ballast weight from shifting. 
     It is yet a further object of the present invention to provide a bait station which can be locked with a key, or can be converted to a fixed latch operator arrangement. 
     Other advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded isometric top view of the bait station of this invention. 
         FIG. 2  is an exploded isometric bottom view of the bait station of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the assembled bait station of  FIG. 4  taken long section line  3 - 3 . 
         FIG. 4  is a cross-sectional view of the assembled bait station of  FIG. 3  taken long section lines  4 - 4 . 
         FIG. 5  is a cutaway partial isometric view of the bait station of  FIG. 1  with a key inserted in the lock formed between the cover and the base of the bait station. 
         FIG. 6  is a cutaway partial isometric view of the arrangement of  FIG. 5  with the key removed and the lock engaged. 
         FIG. 7  is an isometric view of the key of the bait station shown in  FIG. 5 . 
         FIG. 8  is an isometric view of a device which converts a removable key for the bait station of  FIG. 1  into a fixed latch operator arrangement. 
         FIG. 9  is an exploded isometric view of the a device of  FIG. 8   
         FIG. 10  is an isometric side view, cut away in section, showing the device of  FIG. 8  and a portion of the bait station of  FIG. 1 . 
         FIG. 11  is an isometric view of an alternative embodiment of the key of  FIG. 5 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring more particularly to  FIGS. 1-11 , wherein like numbers refer to similar parts, a bait station  20  is shown in  FIGS. 1-4 . As shown in  FIG. 1 , the bait station  20  has a base  22  and a cover  24  joined by an integral hinge  26 . The cover is arranged to close over the base and together with the base defines an interior volume. The base  22 , cover  24 , and hinge  26  may be formed as an integral injection molded part. The base  22  has portions defining a ballast containment space  55 . A ballast weight  28  weighing approximately 7 to 14 pounds is placed in the base  22  within the containment space. The volume of the ballast weight is about 25-200 cubic inches. A molded tray  30  is disposed on top of the ballast weight. The bait station  20  base  22  has a floor  32  which is generally flat but has two inwardly projecting nesting ridges  34  which allow a plurality of bait stations  20  to be stacked, such that the ridges  34  engage with corresponding outwardly projecting cover ridges  36  on the cover  24  of a similar stacked bait station. The two nesting ridges  34  also engage corresponding indentations  35  in the bottom surface  37  of the ballast weight  38  which are shown in  FIG. 2 . The inter-engagement of the nesting ridges  34  and the indentations  35  in the ballast weight  38  allow various sizes of ballast weight to be used in the same bait station so if desired. Smaller ballast weights may be manufactured which retain this inter-engagement with the base indentations. A smaller ballast weight having shorter the sides  39  as indicated by the dashed lines  41  in  FIG. 2  can be used because the inter-engagement restricts side to side motion of the ballast weight  38  by the interaction of the two nesting ridges  34  and corresponding indentations  35  in the bottom surface  37  of the ballast weight  38 . 
     The base  22  has a peripheral wall  38  of four segments  33  forming a rectangle which surrounds the floor  32 . The base wall  38  extends upwardly to engage a corresponding cover peripheral wall  40  which extends downwardly from a cover  24  upper wall  42 . The peripheral wall  38  of the base  22  meets the cover  24  downwardly depending wall  40  along a labyrinth seal  43 , shown in  FIG. 3 , which resists penetration of an object between the base and the cover. 
     As shown in  FIG. 1 , portions of the base peripheral wall  38  define rodent access openings  44  which are opposed to each other along a first segment  46  of the base peripheral wall  38 . The rodent access openings  44  preferably open at or just above the floor  32  of the base  22  so that a rodent moving over the ground or surface  47  which supports the base  22  of the bait station  20  can readily enter. The peripheral wall  38  and the floor  32  define a base interior  48 . As shown in  FIGS. 1 and 3 , portions of the floor  32  are arranged to form upwardly extending ramps  50  which begin just inside the openings  44  and extend upwardly substantially to or slightly above the height of the ballast weight  28 . Ramp side walls  53  separate the rodent access paths defined along the ramps  50  from the ballast containment space  55  in the base  22 . The ballast weight  28  can substantially fill the base interior  48  including about ¾ of the portion of the base which is between the ramps  50  to a depth of about 1¼ inches, depending on total ballast weight volume. The ramps  50  extend upwardly between the first side  46  and short interior walls  52  which extend upwardly slightly above a level defined by the ballast weight  28 . 
     As shown in  FIG. 1 , the tray  30  has two parts, a landing  54  which extends between the ramps, and a tray proper  56  which receives rodent traps  57  or bait blocks  58  as shown in  FIGS. 3 and 4 . The tray  30  has a generally raised edge  61  to contain feeding debris from the bait blocks  58 , and is generally divided into two outer stations  63  designed to support bait blocks or rodent traps, and one central station  65  configured to hold a rodent trap  57 . The outer stations have raised platforms  67  which provide space for structural grids  69  underlying the platforms. The structural grids  69  provide support for rods  71  which extend into rod pockets  73  which extend into the grids. As shown in  FIG. 1 , the tray  30  rests on the tops  51  of the ramps  50  and on eight tabs  59  arranged along the base side wall  38 . The tray thus need not be supported by the ballast weight  28  over which it extends. Two tabs  59  extend outwardly of each wall segment  33  to support the tray  30  in its proper position with respect to the base  22  and the ramps  50 , even if the bait station is used without the ballast weight  28 . 
     The tray  30  has two short tray walls  60  which extend upwardly from the tray proper  56 . The short tray walls  60  are preferably formed with vertical ribs  62  which provide frictional gripping surfaces when engaged between a user&#39;s thumb and first two fingers. When the bait station cover  24  is open, the tray  30  may easily be removed by gripping the two short tray walls  60 , one in each hand, and extracting the tray vertically. When the tray  30  is removed it may easily be inverted for cleaning to dispose of loose material which is accumulated on the upper surface of the tray. 
     As shown in  FIG. 1 , two resilient fingers  64  extend upwardly from the base. The fingers have hooks  66  arranged to engage a flange  68  on the cover when the bait station cover  24  is closed on the base, as shown in  FIGS. 3 and 4 . Thus closing the cover on the base causes the cover of the bait station to latch or lock to the base. The bait station is unlocked from the closed configuration by a key  70 , best shown in  FIG. 7 . The key  70  has two prongs  72 ,  74  of differing cross section configured to pass through key hole openings  76 ,  78  in the cover  24  and to push against the resilient fingers  64 , to thereby release the hooks  66  from the flange  68  and allow the bait station cover  24  to open, as shown in  FIG. 5 . The key  70  is arranged for simple one-handed operation of the lock and the cross sections of the prongs  72 ,  74  are mirror image such that the key can work in either of the two possible orientations. Once the key&#39;s two prongs  72 ,  74  are inserted through the base corresponding openings  76 ,  78  to unlock the cover  24 , the key can remain in lock the cover is opened by using the key as a handle to lift the cover. A short U-shaped ledge  79  is positioned under the openings  76 ,  78  to aid in finding the openings and guiding the key into the openings. The design of the key and the keyhole openings can be easily customized with various shapes of constant cross-section, and matching corresponding keyholes, by simply forming a new key mold, and a new retractable mold piece to form the keyholes. 
     As shown in  FIG. 11 , an alternative embodiment key  118  has a single prong  120  which actuates both resilient fingers  64 . The single prong  120  is preferably selected with symmetry such that the key can work in either of the two possible orientations. 
     When the cover  24  is locked to the base  22 , the tray  30  is also locked against movement by pairs of flanges  86 ,  88 , shown in  FIG. 1 , which extend downwardly and outwardly of the cover side wall  40  to engage the tray  30  against the tabs  59  as shown in  FIG. 3 . The flanges  86  engage a tray lip  81 , shown in  FIG. 1 , which terminates a flange  83  which extends upwardly from the landing  54 , best shown in  FIGS. 2 and 3 . The flanges  88  further engage a lip  85  which terminate the edge of the tray  30  opposite the landing  54 , as best shown in  FIGS. 1 and 3 . 
     As shown in  FIGS. 1 and 4 , a baffle  80  extends downwardly from the cover  24 . An opening  87  in the baffle  80  defines an entryway from the tray landing  54  to the tray proper  56 . The opening  87  is arranged to force a rodents to pass over the trigger  89  of a rodent trap  57  as shown in  FIG. 4 . 
     Rodents may be additionally directed toward the rodent trap  57  by second baffles  90 , as shown in  FIGS. 1 and 3 . The second baffles  90  extend all the way across the cover  24  as shown in  FIG. 1  to strengthen the cover to support multiple weight containing bait stations when stacked for shipping. The second baffles  90  extend from the cover baffle  80  toward the rodent trap. The second baffles  90  extend downwardly from the cover upper wall  42  and are generally aligned with the short tray walls  60 . The second baffled and the short tray walls, although not engaged, together guide rodents entering the opening  87  to pass over the trigger  89  of the rat trap  57 . A suitable rodent trap is shown in U.S. Pat. No. 6,574,912, the disclosure of which is incorporated herein by reference. 
     As shown in  FIG. 3 , the cover baffle  80  has portions on ether side of the opening  87  which are closely spaced from the upwardly extending portions  82  of the tray  30 . The upwardly extending portions  82  of the tray and the downwardly extending portions of the baffle  80  nearly engage so that when the cover  24  is closed on the base, the baffle  80  prevents substantial movement of the tray  30 . When the cover is closed the ballast weight  28  is held between the tray  30  and the base  22  and prevents the ballast weight from substantial movement during shipping. The tray upwardly extending portions  82 , as shown in  FIG. 3 , have downwardly depending lips  94  which overlap the insides  96  of the ramp side walls  53 . Even the short depending lips  94  stiffen the tray  30 , which need not extend to overlap the insides  96  of the ramp side walls  53 . Portions of the first side  46  define holes  98  for tying the bait station  20  to a pipe or other fixed object. The base floor  32  has a hole  99  for screwing the base  22  to, for example, a building floor, obviate the need for the ballast weight in those situations. 
       FIGS. 7-10  show an alternative to the use of a key for opening the bait station to gain access to the bait station interior. In certain controlled settings where unauthorized personnel do not have access to the bait stations, such as within a poultry or pork operation the key-lock system shown in  FIGS. 5-7  can be replaced with a fixed latch operator mechanism  100  without any modifications to the bait station  20 . 
     The latch operator mechanism  100  comprises a handle part  102  joined to a key part  104 , as shown in  FIG. 9 . The key part has two prongs  106  joined by a transverse actuation bar  108 . The two prongs  106  of the key part are installed in the bait station by sliding the prongs through the lock key holes  76  and  78  from the inside of the bait station  20  so that the actuation bar  108  is positioned in the space  110  between the hook  66  and the cover  24  shown in  FIG. 6 . The handle part  102  has pockets (not shown) which receive and retain the ends  112  of the key part prongs  106  which project from the cover. When the handle part is assembled to the key part  104 , the latch operator mechanism  100  is formed. The latch operator mechanism  100  is shown installed and in the activated position in  FIG. 10 . 
     To operate the latch operator mechanism  100 , the handle  102  is pressed toward the cover  24  so that the actuation bar  108  presses against the locking fingers  64  deflecting them as shown in  FIG. 10  to open the latch. Following the unlatching operation, in a way analogous to that previously described with respect to the key  70 , the handle  102  is used to raise the cover of the bait station  20 . In assembling the latch operator mechanism  100  the key part  104  can be joined to the handle  102  by small clips  114  which resiliently snap under bars  116  on the handle, permanently joining the prongs  106  of the key part to the handle. A similar latch operator mechanism can be configured based on the alternative embodiment key  118 . 
     It should be noted that the tray contains a cardholder structure opposite landing  54 , where a note card for recording the status of the bait station may be retained. It should also be noted that the generally raised edge  61  of the tray  30  has a portion which is further raised to shield the lock mechanism from debris and rodent access. 
     It should further be understood that the resilient fingers can be mounted to either the cover or the base, but it is preferable that the key enter through the cover so that the key can act as a handle for lifting the cover. 
     It should be understood that preferably the entire access opening  44  or at least most of it is positioned below the tray  30 . 
     It should be understood that the ballast weight  28  will preferably fill the base  22  substantially flooding, and substantially conforming to the base interior  48  beneath the tray  30  and in between the short interior walls  52 , so that a portion of the ballast weight is positioned beneath the tray landing  54 . 
     It should be understood that where bait is described as used within the station, the station will generally contain either mechanical traps or rodenticide, but instead of rodenticide the bait station may simply be used with bait to detect the presence of the targeted species, or the bait may include a fluorescent dye or other additives for tracking the activities of the targeted species. 
     It should be understood that paper towel dispensers using one or two prong keys which are positioned to actuate resilient prongs and to engage and lift the lid are known in the prior art. 
     It is understood that the invention is not limited to the particular construction and arrangement of parts herein illustrated and described, but embraces all such modified forms thereof as come within the scope of the following claims.