Abstract:
A bait station system has a bait station mounted to a base. The bait station has the general shape of a box with a locking hinged lid. The box has side walls with openings so that rodents can enter into the box and gain access to poison bait or a mechanical trap. The base has a lower tray for receiving a weight. The lower tray has a lower surface which may be glued, attached by a screw, bolt, or earth anchor to a planar surface. The bait station is releasably mounted to the base by a locking mechanism which can be unlocked only by gaining access to the interior of the box forming the bait station.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     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 in general and to rodent bait stations in particular, and more particularly to rodent bait stations and means for anchoring them to a structure or the ground. 
     Rodents such as mice and rats, which are often exotic species introduced by the spread of civilization; are serious pests which carry diseases and consume and spoil food for use by domestic animals and humans. A common and effective method for eliminating rodents is to employ poison bait. The poison bait is most effectively contained in a bait station, which is a box or container which controls access to the poison bait, limiting access to the poison to the targeted pests. The bait station, and the bait in the form of a bait block, is often designed so that the bait block is pinned or otherwise confined within the bait station. By pinning the bait block in place it is not easily removed by the targeted pests but rather must be consumed within the bait station. To prevent a bait station from being tipped over or moved, the station is often physically attached to a mounting surface, structure, or ballast weight, using glue, twisted wire, adhesives, or fasteners. The bait station normally incorporates a lock which allows the station to be opened and the consumption of bait to be monitored or replaced. However, as the rodents consume the bait, the interior of the bait station becomes soiled with droppings, bits of bait block and other materials such that it is desirable to be able to free the bait station from the structure or ballast to which it is mounted so that the interior of the bait station may be emptied by inverting the main station. There is a conflict between fixedly mounting the bait station, and the simplicity of cleaning the bait station by turning it upside down and knocking out the debris. 
     SUMMARY OF THE INVENTION 
     The bait station system of this invention employs a bait station mounted to a base. The bait station has the general shape of a box with a locking hinged lid. The box has side walls with openings so that rodents can enter into the box and gain access to poison bait or a mechanical trap. The base has a lower tray for receiving a weight, such as one or two concrete paver blocks. The lower tray has a lower surface which may be glued to a planar surface, for example the floor of the building. The lower tray has one or more holes such that a screw or bolt or earth anchor may pass through the lower tray to attach the base to a planar surface. The base may be anchored to a planar surface by the force of gravity acting on the weight contained in the base, or may be attached to the ground, or a structure by glue or a mechanical anchor of some type. The bait station is releasably mounted to the base by a locking mechanism which can be unlocked only by gaining access to the interior of the box forming the bait station. 
     Access to the interior of the bait station is controlled by a key lock, so the bait station cannot be separated from the base without the key which provides access to the interior of the bait station. However, once the bait station is opened to determine whether it has been visited by the targeted pest, the bait station can be readily detached from the base, so the bait station may be cleaned by inverting, replaced with another bait station, or temporarily moved to a work area. 
     The locking arrangement between the base and the bait station may be arranged as two keyed posts which pass through openings in one wall of the bait station, the keyed portion of the posts being passed through the opening by tilting the bait station and the one wall so that the wall is at an acute angle with respect to the axes of the posts, so that when the wall is made perpendicular to the axes of the posts, the keyed portions of the posts lock the posts to the wall of the base. In combination with the keyed posts, the base has at least one elastically biased latch which passes through an opening in a portion of the floor of the box of the bait station which is opposite and spaced from the wall through which the keyed posts pass into the bait station. When the bait station is returned to a position such that the wall is perpendicular to the axis of the keyed posts, a ramp on the elastically biased latch forces deflection of the latch surface allowing it to pass through the opening in the floor of the box. The opening in the floor of the box is positioned and sized so that when the latch surface passes through the opening in the floor, the box returns to an unbiased position and the latch surface prevents the floor of the box from being raised to clear the latch. 
     It is a feature of the present invention to provide a bait station system in which a bait station is releasably connected to a base. 
     It is another feature of the present invention to provide a bait station system in which a bait station can be mounted to prevent movement of the bait station, and at the same time can be readily unmounted to permit movement of the bait station. 
     It is a further feature of the present invention to provide a bait station with a keyed entry which also provides access to a mechanism for releasing the bait station from a fixed base. 
     It is yet another feature of the present invention to provide a bait station system which divides the functions typically performed by a bait station between two releasable components. 
     Further objects, features and 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 a side elevational cross-sectional view of the bait station mounted to a base of this invention. 
         FIG. 2  is an isometric view of the base of  FIG. 1  with weights shown in exploded view. 
         FIG. 3  is a side elevational cross-sectional view of an alternative embodiment bait station mounted to an alternative embodiment base of this invention. 
         FIG. 4  is an isometric view of the base of  FIG. 3 , with weights shown in exploded view. 
         FIG. 5  is a schematic view of the bait station mounted to the base of this invention. 
         FIG. 6  is a fragmentary cross-sectional view of a bottom wall connection between the bait station and base of  FIG. 1 . 
         FIG. 7  is a fragmentary side view, partially broken away in section, of the side wall connection between the bait station and base of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring more particularly to  FIGS. 1-7  wherein like numbers refer to similar parts, a bait station  20  mounted to a base  22  forming a bait station system  23  is shown in  FIG. 1 . The bait station  20  is generally configured in accordance with the disclosure of U.S. Pat. No. 5,448,852 which is incorporated herein by reference. The bait station  20  comprises a molded plastic box  24  having a lid  26  joined to the box by an integrally formed hinge  28 . The box  24  has a floor  30  and upwardly extending side walls  32 . The side walls have two openings  34 , as shown in  FIGS. 1 and 2  to permit entry and egress of rodents. Rodenticide bait  21  is positioned within the bait station with respect to molded barriers and support structures  36  which retain and position the bait. 
     A bait station such as disclosed in U.S. Pat. No. 5,448,852 benefits from being anchored to the ground, or other structure on which it is mounted. Such mounting prevents the bait station from being moved or rodenticide from being spilled by the tipping of the bait station. However, anchoring the bait station makes it more difficult to clean the bait station, by, for example, turning it upside down and knocking against the side of a waste container. The base  22  provides the benefit of fixedly mounting the bait station  20  while retaining the advantages of being able to easily release the bait station  20  so it can be cleaned. The base  22  is arranged to rest on a support surface  38  such as the ground or a floor or structural member of a building. Base side walls  39  extend up from the support surface  38  and serve to elevate the bait station  20  above blocks or other weights retained with the base. 
     The base  22  has structures which aid in holding it in place with respect to the support surface  38 , either by adding weight to the combined assembly, or by facilitating the engagement of the base by fasteners such as screws  40 , a ground anchor  44  as shown in  FIG. 5 , an adhesive such as LIQUID NAILS® adhesives manufactured by the Liquid Nails Division of ICI Paints of Strongsville, Ohio, or a wire or cord  56  which extends about a structural member, as shown schematically in  FIG. 5 . 
     For adding weight to the assembly, the base  22  has portions which form a tray  46  as shown in  FIG. 1 . The tray  46  has a floor  96  with upwardly extending side walls  47 . The tray side walls  47  are spaced within the base side walls  39 , and may be connected to the base side walls by stiffening ribs  49  as shown in  FIGS. 1 and 2 . A ballast weight  48  which may be one or two bricks or concrete pavers is placed on the floor  96  of the tray  46  within the side walls so that gravity acting on the pavers holds the base  22  to the support surface  38 . Alternatively, the weight may be a conventional weight-lifting disc or plate, not shown received within the tray  46 . 
     The bait station  20  incorporates a pair of locks  50  which are operable by a key  54  shown in  FIG. 5 . One lock  50  is shown in  FIG. 1 , and is shown schematically in  FIG. 5  and disclosed in detail in U.S. Pat. No. 5,448,852. The locks  50  serve to control the entry into the interior  52  of the bait station, where the rodenticide is held in the bait holding structures  36 . By arranging locking structures between the base  22  and the bait station  20  which can only be unlocked by gaining access to the interior  52  of the bait station  20 , the same key control system also controls access to the ability to separate the bait station from the base  22 . 
     As shown in  FIGS. 1 and 2  the base  22  has an injection molded shell structure  57 . The side walls  39  of the shell structure  57  have a lower peripheral edge  58  which rests in contact with the support surface  38 . The shell structure  57  extends upwardly along a pair of symmetrically arranged ramps  60  to a platform  62 , which defines a horizontal plane  64  on which the bait station  20  is positioned. Between the ramps  60  on opposite sides of the platform  62  are arranged the locking mechanisms. 
     One set of fixed locking structures comprises two posts  66  which extend towards the bait station from an upwardly projecting mounting structure  68  shaped somewhat like a bookend. The two posts  66  extend over and parallel to the horizontal plane  64  defined by the platform  62 . The mounting structure  68  is positioned between the ramps  60  and terminates one side of the platform  62  on which the bait station  20  is positioned and locked to the base  22 . Each post  66  has an end  70  distal from the mounting structure. The distal end  70  has locking portions  74  which extend unsymmetrically and upwardly of the distal end  70 . As shown in  FIG. 7 , the locking portions have an upper cam surface  71  which is inclined away from the mounting structure  68  to aid in aligning the rear wall  72  on the posts as the bait station is mounted to the base. 
     The bait station  20  rear wall  72  is part of the upwardly extending walls  32  of the box  24  and has portions forming a pair of holes  76  which correspond to and are arranged for receiving the posts  66 . The posts  66  have cross-sections which correspond substantially to the shapes of the holes  76 , however the holes  76  are arranged so that they cannot accommodate the locking portions  74  when the rear wall  72  is moved in the horizontal plane  64 . However, if the rear wall  72  is tipped towards the mounting structure  68  approximately 30° from the vertical, and passed first over the locking portions  74  of the posts  66 , the rear wall  72 , and the bait station  20  can then be pivoted to the horizontal so that the posts extend through the holes  76 , locking the bait station against horizontal movement to the posts and to the mounting structure  68 . 
     The fixed locking structures formed by the posts  66  are complemented by barbed latching fingers  78 , shown in  FIG. 6 , which extend upwardly from the base  22  to engage within slots  92  in the bait station  20 . The engagement of the latching fingers  78  with the bait station slots prevents the bait station  20  from being pivoted, which, in cooperation with the posts  66 , effectively locks the bait station  20  to the base  22 . The barbed latching fingers  78  are located opposite the mounting structure  68 , and are formed with the injection molded shell  57 . The latching fingers  78  extend from below the platform  62  to a position above the platform. A portion  80  of each of the latching fingers  78  which is above the platform includes a barb  82  defined by an apex  84  with a downwardly extending ramp  86  which terminates in a locking downwardly facing surface  88  approximately parallel to the horizontal base platform  62 . 
     The bait station  20  has a front wall  90  which forms a part of the upwardly extending side walls  32 . Portions of the bait station floor  30  adjacent to the front wall  90  form openings or slots  92  which receive the barbed latching fingers  78 . The openings  92  are rectangular and the sides  83  of the opening distal from the adjacent front wall have slightly raised ramps  85  leading up to the opening sides  83 . The ramps  85  are provided so that the locking downwardly facing surface  88  of a latching finger is substantially supported near the opening  92 , as illustrated in  FIG. 6 . Such a supporting arrangement increases the resistance to the floor  30  of the bait station  20  being pulled over the barbs  82 , and helps to retain the assembly in a locked condition. 
     To mount the bait station  20  to the base  22 , the bait station is tilted so that the floor  30  makes an angle of approximately 30° with the plane  64  of the platform  62 . The holes  76  in the rear wall  72  of the bait station are positioned over the posts  66  so that portions of the rear wall rest on the posts. The bait station  20  is then pivoted outwardly so that portions of the floor  30  surrounding the openings  92  engage the ramps  86  as the apexes  84  pass through the floor  30 . The operation of the floor  30  pressing downwardly on the ramps  86  forces the latching fingers  78  and the attached barbs  82  to deflect toward the front wall  90  allowing the entire ramp structure to pass through the openings  92 . The latching fingers  78  are sufficiently resilient so they return to their undeflected position, such that the locking surfaces  88  are now in opposition to the floor  30 , preventing upward movement or tilting of the bait station  20 . 
     As shown in  FIGS. 2 and 7 , the base  22  is preferably provided with fins  89  which project upwardly at the rear of the base on either side of the mounting structure  68 . As best shown in  FIG. 7 , the fins  89  are narrow plate-like elements about 1/16 inches thick, and may be about one inch long and from ¼ to ¾ inches tall. The fins  89  are positioned to engage the rear wall  72  of the bait station and serve to stiffen the combined structure to help to prevent shifting of the bait station with respect to the base when the assembly is subjected to impact. If the bait station shifts horizontally too much, there is the possibility that the flexible latching fingers  78  will come out of engagement with the slots  92  in the bait station floor, thereby allowing the bait station to become separate from the base. The fins  89  help to prevent this shifting, and thus resist separation of the bait station from the base when either is struck. 
     To remove the bait station  20  from the base  22 , the key  54  is used to open the lid  26 , gaining access to the interior of the box  24  where rodenticide and/or mechanical traps are positioned. When an operator has gained access to the interior of the bait station  20 , the latching fingers  78  are readily released from engagement with the floor  30  by pushing in the horizontal plane against the ramps  86  which extend down from the apex  84  of the barbs  82 . Pushing against the barbs  82  moves the latching fingers  78  so that they can pass through the openings  92  in the floor  30  of the box  24  of the bait station  20 . Once the bait station  20  is released from the latching fingers  78  it can be rotated out of the horizontal plane until the holes  76  in the rear wall  72  can be lifted over the posts  66  mounted to the mounting structure  68 , thereby releasing the bait station  20  from the base  22 . 
     The base  22  is preferably an injection molded part formed as a single piece. The ramp  60  shown in  FIG. 2  provides easy access for rodents to the openings in the side walls  32  of the bait station. As rodents can readily climb vertical walls, the form of the ramp is not critical. The ramps  60  terminate at flat triangular surfaces  94  which form part of the platform  62 . The platform need have relatively little support area because the bait station  20  is not highly loaded on the platform. The platform  62  mainly serves the function of positioning the bait station  20  in conjunction with the mounting structure  68 , the posts  66 , and the latching fingers  78 . The ballast tray  46  has side walls which extend downwardly from the platform  62  terminating in the floor  96  which lies substantially in a plane defined by the lower peripheral edge  58  of the base  22 . The floor  96  has portions defining a number of holes, the larger central hole  98 , shown in  FIG. 2 , may be used with a ground anchor  44  as illustrated in  FIG. 5  such as a duck bill. The smaller holes  100  may be used with drywall screws  40  or similar anchors to attach the base to a wood or plastic floor deck. For convenience of injection molding, the ballast tray  46  may be open to an empty space underneath the mounting structure  68  to allow the pavers to overhang underneath the mounting structure to obtain, for example, a total brick containment space slightly over 8″×8″×2.5″ which will accommodate one or two of a large range of pavers and bricks with a total weight of approximately 8 to 10 pounds. The base  22  can also be attached to a structural member of a building by using wire or cord, as illustrated in  FIG. 5 , between either the holes  100  in the floor  96  of the tray  46 , together with holes  102  formed in an outer wall  104  of the mounting structure  68  or in other parts of the base shell  57 . 
     An alternative embodiment bait station system  123  is shown in  FIGS. 3 and 4 . The alternative bait station system  123  employs a bait station  120  which has substantial similarities with the bait station disclosed in U.S. Pat. No. 6,397,517 which is incorporated herein by reference. The bait station  120  illustrates the rodent access holes  34  necessary to the function of a bait station. The bait station  120  is releasably attachable to a base  122 , with an approach similar to that disclosed with respect to the bait station system  23 . The base  122  is preferably an injection molded shell  157  which has a lower peripheral edge  158  and symmetrically arranged ramps  160  which extend upwardly to a platform  162  on which the bait station  120  is supported. The base  122  has a mounting structure  168  from which extend a plurality of posts  166 , the posts have locking portions  174  which engage with holes  172  formed in a rear wall  173  of the bait station  120  as illustrated in  FIG. 3 . The post  166  interlocking portions  174  are engaged with the rear wall  173  in a manner similar to that described with respect to the bait station  120  above. Latching barbed fingers  178 , are again arranged to extend upwardly from the base  122  through a plane defined by the platform  162 . The barbed fingers  178  extend through holes  192  in the floor  130  of the bait station  120 . Inclined ramps  186  forming part of the barbed fingers  178  again force deflection of the fingers when the floor  130  of the bait station  120  is brought down into engagement with the platform  162 . Once through the holes  192 , the fingers  178  return to the undeflected position so that locking surfaces  188  underlying the ramps  186  prevent the upward movement of the floor  130 , thereby locking the bait station  120  to the base  122 . A pair of key locks (not shown) similar to those illustrated with respect to the bait station  20  of  FIG. 1  prevent access through the hinged lid  126  to the interior  152  of the bait station  120 . 
     The base  122  illustrated in  FIG. 4  is very similar to the base  22  illustrated in  FIG. 2  and incorporates a tray  146  of similar dimension to the tray  46  illustrated in  FIG. 2 , which again can perform the function of retaining one or several ballasting weights such as brick or concrete pavers  48  or other weight element. Again the base  122  may be attached to the ground or structure by any of the mechanisms indicated in  FIG. 5 . The base  122  has fins  189 , shown in  FIG. 4 , to help to stiffened the combined base and bait station assembly. 
       FIG. 5  is a schematic illustration of the bait station system  23  illustrated in  FIGS. 1 and 2 , and serve to illustrate the general principle employed by the bait station system. The bait station system  23  has two basic parts: a bait station  20  having those features which are arranged to dispense rodenticide to rodents, or to contain rodents traps, within the interior of the bait station, and a base  22  which has multiple structures arranged to allow anchoring the base to another structure, typically the floor or ground but possibly also to a post or beam. A locking mechanism which extends between the base  22  and the bait station  20  locks the bait station to the base, wherein the locking mechanism can only be undone when access is obtained to the interior  52  of the bait station. In addition to the illustrated base resilient fingers which engage with the bait station through holes, other locking mechanisms could be employed, for example those using a removable piece within the bait station which prevents the withdrawal of projections extending into the bait station from the base, similar in function to a cotter pin arrangement. The bait station in turn is constructed to prevent access to the bait station interior without a key. 
     It should be understood that a keylock in the context of this application can include a cable tie which functions as the key and part of the lock, the cable tie passing through a hole in the lid and a hole on the box to lock the lid to the box of the bait station. 
     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.