Abstract:
A bird feed dispenser for wild birds with squirrel-resistant mechanism that occludes feed ports when a non-bird having a weight sufficient to activate the mechanism engages a portion of the roof or a perch thereon. The dispenser includes at least two feed ports, corresponding perches, and a torsion spring that provide biasing force for the mechanism. The occlusion of feed ports in the dispenser is such that when a non-bird having weight sufficient to activate the mechanism engages a portion of the roof or a perch thereon, all the feed ports are obstructed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. §119 to U.S. provisional patent application 61/650,711, which was filed May 23, 2012, entitled “WILD BIRD FEED DISPENSER WITH SQUIRREL-RESISTANT MECHANISM,” and is hereby incorporated by reference in its entirety into the present application. 
    
    
     TECHNICAL FIELD 
     Aspects of the presently disclosed technology relate to wild bird feed dispensers. In particular, the technology relates to wild bird feed dispensers that include mechanisms that resist non-birds from accessing the feed in the dispenser. 
     BACKGROUND 
     Attracting wild birds by feeding birdseed is a very popular hobby. Usually, persons who wish to attract wild birds, specifically song birds, with feed do not wish to also attract non-bird species, specifically squirrels. Squirrels enjoy eating birdseed and can discourage wild birds from visiting the birdfeeder device, especially when the squirrels are likely to consume most of the birdseed. This can be expensive as well, since feeding squirrels and such non-bird species as well as wild birds can be quite burdensome. There are many mechanisms and strategies to deny squirrels and the like access to the bird seed in a bird feeder. Most such mechanisms, as here, rely on the substantial difference between the weight of a typical squirrel and that of a desirable song bird. 
     SUMMARY 
     Disclosed is a feeder for dispensing birdfeed to wild birds but resists dispensing that birdseed to non-birds. These feeders have a hanger for suspending the bird feeder from a support, and a housing having a generally vertically extending wall. This wall defines a feed reservoir for a supply of the birdseed to be dispensed. The housing wall has at least two feeding ports formed through the wall. The housing also defines an upwardly facing opening into the feed reservoir, primarily for filling the feed reservoir with birdfeed, preferably birdseed. The feeder also has a roof assembly which removably covers the upwardly facing opening into the feed reservoir. This roof assembly is mounted for movement relative to the housing. There is a perch at each of the at least two feeding ports. This perch is mounted for movement relative to its adjacent port. There is a mechanical link attached to the perch and extending to and linking the roof assembly, whereby movement of the roof assembly relative to the housing causes to perch to move relative to its adjacent port. The roof assembly includes at least one opening sized to permit the hanger to pass through the roof whereby the hanger attaches to and suspends the housing and whereby movement of the perch or movement of the roof assembly relative to the housing is permitted even when the feeder is suspended by this hanger. There is at least one torsion spring for biasing the perch into a first position relative to its adjacent port. This torsion spring permits the perch to move to a second position when a non-bird moves either the roof assembly or the perch downwardly against the bias of this torsion spring. The link preferably extends generally vertically from the perch upwardly to engage a portion of the roof assembly that extends outwardly from and beyond the wall of the housing. This mechanical link most preferably has an aperture aligned with a feed port at least in one of the spring biased positions of the perch. 
     Other implementations are also described and recited herein. Further, while multiple implementations are disclosed, still other implementations of the presently disclosed technology will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative implementations of the presently disclosed technology. As will be realized, the presently disclosed technology is capable of modification in various aspects, all without departing from the spirit and scope of the presently disclosed technology. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a perspective view of one embodiment. 
         FIG. 2  is an exploded view showing the main parts of the first embodiment. 
         FIG. 3  is a partial close-up view of a moveable perch and an adjacent feed port. 
         FIG. 4  is a view similar to  FIG. 3  with a base portion removed to show torsion springs. 
         FIG. 5  is a vertical cross-section through the center of the embodiment of  FIG. 1 . 
         FIG. 6  is a close-up partial sectional view through an upper portion of the first embodiment showing the roof assembly, the hanger and the housing. 
         FIG. 7A  is another embodiment shown in perspective. 
         FIG. 7B  is very similar to  FIG. 7A  with the roof assembly and actuators depicted transparently. 
         FIG. 8  is a plan view of the embodiment shown in  FIG. 7  with a transparent roof assembly. 
         FIG. 9  is an exploded view of the main parts of the embodiment of  FIG. 7A . 
         FIG. 10  shows a pair of port shutters with their inter-engagable linkages separated for clarity. 
         FIG. 11  shows a pair of port shutters with their linkages inter-engaged. 
         FIG. 12  is another view of the port shutters of  FIG. 11 . 
         FIG. 13  shows the link extending from the perch to engage the underside of the roof assembly. 
         FIG. 14  is a partial cross-sectional view of a pair of movable perch assemblies. 
         FIG. 15  shows the embodiment of  FIG. 7A  with a hidden port shutter in order to view a torsion spring adjustably engaging the housing. 
         FIG. 16  is a close up of the link between the perch and the underside of the roof, as well as a latch and latch stud. 
         FIG. 17  is a side view of the embodiment of  FIG. 7A , wherein a port shutter is depicted transparently. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the various figures, the birdfeeder assembly  10  comprises two generally vertically symmetrical housing halves of injection molded preferably transparent or translucent polymer. These two housing halves may be held together by glue or screws or may be assembled using clips and hinging mechanisms so that the housing  12  can be easily cleaned after being used to feed birds. The housing  12  preferably includes internal baffles  14  to help distribute the seed that is poured into the top upwardly facing opening towards various feed ports  16 . The feed ports  16  are thus molded-in passages through the housing  12  wall from the outside of the housing  10  to the interior where the bird seed is held within the housing  12  reservoir. Referring to the embodiment of  FIG. 1 , the housing  12  includes four feed ports  16 , two on each diametrically opposite side. Each pair of feed ports  16  is arranged one vertically above the other. The bottom of the feed reservoir is defined by a pair of generally curving walls  18  that engage along adjacent edges or surfaces to define a generally solid bottom which slopes to the bottom-most pair of feed ports  16 . As seen in  FIG. 4 , below this bottom surface the housing  12  walls continue and support and define a pair of studs  20  about which a pair of torsion springs  22  are mounted. As will be detailed, these torsion springs  22  engage a pair of actuators  24  or linkages which mechanically interconnect all of the perches  26  as well as at least a portion of the roof assembly  28 . 
     Referring to  FIG. 3 , a base  30 , preferably of a stamped thin metal similar to the roof assembly  28  and actuator  24  portions as will be detailed, engages and surrounds this lower portion of the housing  12 . As stated previously, this embodiment has four feeding ports  16 . Accordingly, this embodiment includes a perch  26  adjacent to each of the feeding ports  16 . The perch  26  preferably comprises a T-shaped metal protrusion attached to a sheet metal actuator  24  by a pair of lugs  56 . This construction permits the perch  26  to hinge upwardly and fit snugly against the and parallel to the housing  10  for easy compact shipping. More importantly, however, each perch  26  is affixed to the actuator  24  which as will be detailed, is in turn mounted for movement relative to the housing  12 . Referring again to  FIG. 4 , a torsion spring  22  as mentioned previously is mounted at one end to the housing  12  and around an integrally formed stud  20  within the bottom portion of the housing  12 . As seen in  FIGS. 4 and 5 , the distal movable end of the torsion spring  22  engages preferably the lower-most end of the actuator  24 . In this embodiment the torsion spring  22  passes through a slot  32  in the base  30  and serves to help guide the generally vertical movement of the perches  26  and actuators  24  (and at least a portion of the roof assembly  28  as will be detailed.) 
     Referring to  FIG. 6 , the upper-most end of the actuator  24  is affixed, preferably by welding, to a portion of the roof assembly  28 . In more detail, the roof assembly  28  comprises a lid portion  34  which is removably attached to and covers the upwardly facing opening into the feed reservoir of the housing  12 . This portion is separate from but cooperates with a movable, radially-extending outward portion  36  of the roof assembly  28  which is affixed to the upper end of the actuators  24 . These two portions of the roof assembly  28  (i.e., lid portion  34  and the movable portion  36 ) act to close the opening used to fill the seed reservoir and to help shield the feed reservoir and the feed ports  16  from precipitation. The second or movable portion  36  of the roof assembly  28  protrudes radially outwardly beyond the vertical wall of the housing  12  and, as previously discussed, is affixed to the upper end of the actuator  24 . 
     Referring to various figures, a hanger  38 , preferably comprising a flexible steel cable of about a 1/16 th  inch diameter is affixed at each of its ends to a molded in plastic lug  68  at the upper-most edge of the housing  12 . 
     The movable portion  36  of the roof assembly  28  is attached to and moves with the actuator  24  and thus moves against or with the bias of the torsion springs  22  as previously described. Note that the actuator  24  includes an aperture  40  which, in one position of the spring biased perch  26  is aligned with the feed port  16  through the housing  12  wall. If a non-bird species, such as a squirrel, attempts to access the birdseed in the feed when the feeder is hanging from the hanger  38 , usually this requires the squirrel to grip either the roof  28  or one or more of the perches  26 , since the housing  12  has almost no features which can be gripped by the squirrel. The weight of this non-bird species overpowers the spring bias of the torsion springs  22 , causing the movable portion  36  of the roof assembly  28  and the actuator  24  and its attached perches  26  to move downwardly. This downward displacement moves the apertures  40  in the actuators  24  out of alignment with the feed ports  16 , thus occluding or obscuring access to the feed ports  16 . 
     Further referring to  FIGS. 3 and 4 , the movable end of the biasing spring  22  is loosely attached to the actuator  24  and slides in a slot  32  through a peripheral band  42  that extends and connects the lower-most end of each actuator  24  with its opposing actuators  24 . The peripheral band  42  helps guide the actuator  24  in a substantially only vertical direction up and down so that the aperture  40  through the actuator  24  normally aligns laterally as well as vertically with the feed port  16  when a bird is sitting on the perch  26  or at least when any non-bird species such as a squirrel has not deflected the actuator  24  downwardly against the bias of the torsion spring  22 . 
     In a similar manner, each actuator  24  is attached at diametrically opposite locations to the movable portion  36  of the roof assembly  28 . In this way a non-bird species, such as a squirrel may attempt to access the birdseed by climbing down the hanger  38  and gripping the roof  28  portion at any location. Regardless of that location, all of the feed ports  16  become closed or occluded when the actuator  24  assembly slides downwardly, guided by and against the bias of one or more torsion springs  22 . 
     Preferably, the overall assembly  10  includes two torsion springs  22 , each mounted symmetrically opposite from one another and engaging the bottom-most edge of the adjacent actuator  24  on opposite sides of the housing  12 , as seen in  FIGS. 4 and 5 . 
     Referring to  FIGS. 7A and 7B , as well as subsequent figures, this embodiment also uses a pair of actuators  24  or linkages, but these actuators  24  normally bear upwardly on the downwardly-facing surface of a one-piece roof assembly  28 . Each actuator  24  is mounted and guided by a screw  44  attached to a stud in the side of the housing  12  wall. The actuator  24  is capable of displacing a sliding distance  74 , relative to the screw  44  location. The lower-most end of each actuator  24  includes a lug  56  to which is pivotally mounted a moveable perch  26  as previously described, the actuator  24  also has an aperture  40  which when the assembly is not being attached by a non-bird species aligns with and permits access to a feeding port  16  through the side of the housing  12 . A torsion spring  22  mounted within the base  30  portion of the housing  12  engages the housing  12  in a mounting plate  46  at one end and the moveable end engages an inner surface of one of a pair of port shutters  48 . The pair of port shutters  48  is shown separately in  FIGS. 10-12 . These consist of an upper broad portion  50  sized to occlude access through the feeding port  16  when moved towards the port  16  from the inside. Each of these shutters swing from a position spaced from the seed port  16  to a position adjacent to and against the inner surface of the feed port  16  when a non-bird species hangs from or engages the roof assembly  28  or any one of the perches  26  as will be detailed. 
       FIG. 14  shows a pair of perches  26  assembled to and engaging a pair of port shutters  48 . Note that each of these paired perches  26  and shutters  48  pivot about axis x 1  and x 2  respectively. Each of the shutters  48  includes an extension arm  52  with a pair inter-engaging camming surfaces  54  such that if one of the shutters  48  moves towards the feed port  16  to occlude that feed port  16 , the other shutter  48  will also move in this similar pivotal manner about its associated pivoting axis. The movement of the perch  26  is transmitted to the roof  28  or the movement of the roof  28  is transmitted to the perches  26  and thus the port shutters  48  via a lug and screw interconnections  56  as shown in  FIGS. 13 ,  14 , and  16 , among others. 
       FIG. 15  generally shows a close-up of the lower portion of the assembly  10  with the port shutter  48  hidden in order to view the torsion spring  22 . The spring bias provided by the pair of torsion springs  22  can be adjusted by moving the otherwise fixed end of the torsion spring  22  into one of two or many slots  32  formed in the bottom portion of the port shield  58  which is attached in turn to the adjacent portion of the housing  12  wall. The slots  32  in the mounting plate  46  are shown such that placement of the torsion spring  22  in differing slots  32  either increases or decreases the biasing force associated with the spring  22 . The change in biasing force results in different forces necessary to displace the perch  26  and thus occlude the feed in the port  16 . The reason for the variable bias force is that a change in displacement angle  70  between the moving end of the torsion spring (i.e., the end that is housed in the port shutter  48 ) and the static end (i.e., the end that is in the slot  32 ) causes a change in the force necessary to oppose such a force. In such a way, a smaller displacement angle  70  between ends of the torsion spring  22  equates to a higher biasing force necessary to displace the perch  26 . As an example, to increase the force necessary to displace the perch  26  (i.e., to allow for heavier birds to feed), the torsion spring  22  is placed in a slot  32  that increases the bias force. In this example, the bias force will be the largest in the highest or topmost slot  32 . On the other hand, in order to minimize the force necessary to displace the perch  26 , the torsion spring  22  is placed in a slot  32  that decreases the bias force. In this example, the bias force will be the least in the lowest slot  32 . 
     Although the embodiment of  FIG. 7A  includes two slots  32  for altering the biasing force associated with lowering the perch  26  and thus occluding access to the feed, the assembly  10  can includes any suitable number of slots  32 . As an example, the embodiment of  FIG. 1  and/or  FIG. 7A  may include three or four slots  32  for the altering of the biasing force. Whereas the embodiment of  FIG. 1  includes a single slot  32 , it is contemplated that such an embodiment may include additional slots  32 , as similarly depicted with respect to the embodiment in  FIG. 7A . 
       FIG. 15  further illustrates the interaction between the actuator  24 , the mounting plate  46 , and the perch  26 . The actuator  24  couples to the perch  26  at a lug and screw  56  as described previously. As a force is applied to either a portion of the roof assembly  28  or to the perch  26 , the actuator  24  displaces downwardly relative to the mounting plate  46 . The low end of the actuator  24  also includes a notch  66  that accommodates certain movements from the perch  26  when the actuator  24  is in a downward displacement. 
     Referring to  FIG. 16 , the roof  28  is attached to the housing  12  by a latch  60  and a latch stud  62 . In addition, the screw  44  and stud are visible, wherein a downward force on the roof assembly  28  will engage with a top end of the actuator  24  and cause the actuator to displace downwardly relative to the screw  44  and stud, which is coupled to the housing  12 . It is evident from this illustration that the amount of downward displacement of the actuator is determined by the allowable sliding distance  74  of the actuator  24  relative to the screw  44 . 
     The roof assembly  28  toggles or rotates about the latch stud  62 , as seen in  FIG. 16 . The rotation or toggling of the roof  28  is guided or otherwise restrained by guides  72  on either side of the latch  60 . The amount of rotation of the roof  28  effects the downward displacement of the roof  28 . The displacement of the roof can be controlled by appropriate placement of the guides  72  relative to the latch  60  and latch stud  62 . In such a way, the position and angle of the guides  72  will correlate to the sliding distance  74  of the screw  44  so that the downward displacement of the roof  28  generally corresponds with the downward displacement of the actuator  24 . 
     Referring to  FIG. 16 , the hanger  38  extends through an aperture in the roof  28  and is affixed at each of its ends to a molded plastic lug  68  at the upper most edge of the housing  12 , as described previously. 
       FIG. 17  depicts the assembly  10  with a transparent port shutter  48  in order to clearly display the torsion spring  22  and the inner structure of the shutter  48 . The moving end of the torsion spring  22  is mounted within the port shutter  48  such that rotation of the shutter  48  about axis x 1  towards the port  16  decreases the displacement angle  70  for so long as a force is applied. As the force is decreased, on either the perch  26  or a portion of the roof assembly  28 , the shutter  48  rotates about axis x 1  back towards the center of the housing  12 , which correspondingly increases the displacement angle  70 . Further referring to  FIG. 17 , the perch  26  is received in the receiving slot  64  of the port shutter  64 . The receiving slot  64  includes a latch mechanism on the upper side of the shutter  48  that engages with the shaft of the perch  26 . 
     In operation, this bird feeder  10  example functions as follows: The user releases the roof from the housing  12  by deflecting the latches  60  outwardly from over the latch studs  62 , and slides the roof upwardly along a portion of the hanger  38  cable. This exposes the upwardly facing opening into the seed reservoir formed by the walls of the housing  12 . Once the housing  12  is filled with birdseed to form a reservoir of the seed, the interior adjacent the feed ports  16  become filled with seed. The user latches the roof onto the latch studs  62 . The seed filters down through the housing  12  and is distributed to in this case two seed ports  16 . Birds having a normal weight can rest on the perch  26  and feed via the feed ports  16 . The actuators  24  remain relatively unmoving, being held in an upward position by the bias of the one or preferably two torsion springs  22 . Should a non-bird species, such as a squirrel, try to feed from the seed ports  16 , the spring bias of the torsion springs  22  is overcome, thus moving the perch  26  downwardly, which in turn drags the actuator  24  down as well as moves both of the port shutters  48  downwardly and forwardly to occlude the seed ports  16 . Similarly, if a non-bird species such as a squirrel tries to access the seed ports  16  by gripping and hanging from the roof, the roof pivots about the latch studs, pressing on the adjacent actuator  24 . The actuator  24  in turn moves the perch  26  immediately below that side of the housing  12 , and the port shutter closes. Since both port shutters  48  are linked together with the cam surfaces  54  as previously discussed, the other port  16  is closed by the shutter as well, thus defeating any chance that a squirrel or other non-bird species could easily access the supply of seed in the housing  12 . 
     Various modifications and additions can be made to the exemplary embodiments discussed without departing from the spirit and scope of the presently disclosed technology. For example, while the embodiments described above refer to particular features, the scope of this disclosure also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the presently disclosed technology is intended to embrace all such alternatives, modifications, and variations together with all equivalents thereof.