Abstract:
The present invention includes spring loaded elongated cylindrical perches incorporated into bird feeders, wherein the perches have typically a round perch member which, when loaded by an undesirable bird or other pest, will sense the weight of the pest and the weight will overcome the spring loaded perch and the perch will collapse at a fulcrum point thereby dislodging the bird or pest. The spring is designed to have the capability of elongating upon the application of a predetermined force being applied to the spring by means of the weight of the pest on the perch, and then the spring will elongate causing the perch to bend vertically downward with respect to the ground dislodging the pest, and when the longitudinal force on the spring is relaxed, the spring then resumes its relaxed length and draws the perch back into battery with respect to the spring housing assembly.

Description:
This application claims priority from Provisional application Ser. No. 60/174,856, filed on Jan. 7, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to the field of song bird feeders and, more particularly, to bird feeders which prevent unwanted rodents and birds from feeding at the feeder. The feeder of the present invention also provides a great deal of amusement to those watching when an unwanted rodent alights on the feeder. 
     Bird watching is a fulfilling activity for many and provides an educational tool for children in that it increases environmental consciousness. Further, bird feeders assist certain species of birds to find foods and supplements to augment their diets, especially during periods of severe weather. 
     II. Description of the Related Art 
     Not only are there many bird feeders of unlimited designs, there are also bird feeders which have been designed to prevent unwanted birds and rodents from invading and eating from bird feeders which have been designed for the typical lightweight song bird. 
     The prior art has disclosed many devices to effect the discouragement or removal of unwanted pests at the song bird feeder. For instance, there are a great number of weight sensitive, tiltable perches on bird feeders for dislodging the unwanted pest such as shown in the patents to Loken (U.S. Pat. No. 5,105,765), Wessner (U.S. Pat. No. 5,048,461) and Dehls (U.S. Pat. No. 4,541,362). 
     There are many electrical type devices which will shock unwanted pests which alight on a song bird feeder, such as is shown in Fry (U.S. Pat. No. 5,392,732) and Collins (U.S. Pat. No. 5,471,951). 
     Many weight sensitive devices have been shown wherein the food openings in the bird feeder will close if a heavier rodent than the normal song bird sits on the perch near the food opening. The patent to Drakos (U.S. Pat. No. 5,720,238) is typical of this type of mechanism. 
     There are also devices which sense a rodent, such as a squirrel or heavy unwanted bird, which will, at a predetermined point in time, effectively remove the unwanted pest from the feeder. Typical of these prior devices, is the patent to Hibbard (U.S. Pat. No. 5,297,503) and Korb (U.S. Pat. No. 5,690,056). 
     It is to the type of feeders which utilize weight sensitive, tiltable perches to which the present invention pertains. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention and the contemplated problems which have existed and continue to exist in this field, the objectives of this invention include providing a pest proof song bird feeder. The feeder of the present invention is mechanical in nature and presents several embodiments of the basic design. 
     The present invention generally includes spring loaded elongated cylindrical perches incorporated into bird houses and/or bird feeders (the terms are used interchangeably herein), wherein the perches have a typically round perch member which, when loaded by an undesirable bird or other pest, will sense the weight of the pest and the weight will overcome the spring loaded perch and the perch will collapse at a fulcrum point thereby dislodging the bird or pest. It should be noted that, while round perches are convenient, they do not exclude other configurations from the scope of this invention. 
     The spring which is utilized with the perches is designed to have the capability of elongating upon the application of a predetermined force being applied to the spring by means of the weight of the pest on the perch, and then the spring will elongate causing the perch to bend vertically downward with respect to the ground dislodging the pest, and when the longitudinal force on the spring is relaxed, the spring then resumes its relaxed length and draws the perch back into battery with respect to the spring housing assembly. 
    
    
     Other objects, advantages and capabilities of the invention will become apparent from the foregoing description taken in conjunction with the accompanying drawings showing the preferred embodiments of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial elevation view of a birdhouse, partially in section, showing a first embodiment with a spring loaded perch; 
     FIG. 2 is an exploded perspective view of the perch assembly; 
     FIG. 3 is a front elevation view of a birdhouse; 
     FIG. 4 is a partial section elevation view of a birdhouse showing a second embodiment partially in section of a perch assembly; 
     FIG. 5 is an exploded perspective view of the perch assembly of FIG. 4; 
     FIG. 6 is a partial sectional elevation view of another embodiment of a spring loaded perch assembly; 
     FIG. 7 is a bottom plan view of the perch assembly of FIG. 6; 
     FIG. 8 is a partial elevation sectional view of a birdhouse having another embodiment of a spring loaded perch assembly; 
     FIG. 9 is an exploded perspective view of the perch assembly of FIG. 8; 
     FIG. 10 is a partial front elevation view of a birdhouse having another embodiment of a spring loaded perch assembly; 
     FIG. 11 is a horizontal sectional view taken along lines  11 — 11  of FIG. 10; 
     FIG. 12 is a vertical elevation view of a birdhouse incorporating another embodiment of a spring loaded perch system; 
     FIG. 13 is a partial elevation view partially in section of the spring loaded perch assembly of FIG. 12; 
     FIG. 14 is a partial horizontal sectional view of the perch assembly of FIG. 13; 
     FIG. 15 is a partial vertical sectional view of another embodiment of a spring loaded perch assembly; and 
     FIG. 16 is a partial horizontal sectional view of the spring loaded perch system of FIG.  15 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For a fuller understanding of the nature and desired objects of this invention, reference should be made to the following detailed description taken in connection with the accompanying drawings. Referring to the drawings wherein like reference numerals designate corresponding parts throughout the several figures, reference is made first to FIGS. 1,  2  and  3 . The birdhouse  21  has an opening  22  in the vertical face thereof to allow access for the desired songbirds, and enclosed within the birdhouse  21  is a perch assembly  23  located within a suitable aperture  24 . The perch assembly  23   a  comprises a spring housing  25 , an extension spring  26 , a perch sleeve  27  and a perch retainer  28  which is generally round to cover the open end of the sleeve  27 . Shoulder  28   a  of the retainer  28  butts up against perch sleeve end  27   a.  The extension spring has a pair of opposed reentrant ends  29   a  and  29   b.  To maintain the perch assembly within the birdhouse  21 , the spring housing is affixed to the birdhouse  21  by means of a suitable screw  31  which is secured to the birdhouse and thence secured to the spring housing  25 . End  29   b  of the extension spring is also secured to the screw  31  and the extension spring  26  is then threaded through the perch sleeve  27  and end  29   a  is then secured to the perch retainer  28 , through aperture  28   b,  which retainer is closely fitted to the perch sleeve. As is evident, the spring housing  25  and the perch sleeve  27  are of hollow cylindrical shape. Once the perch assembly  23   a  is fully assembled and placed within the aperture  24 , the birdhouse  21  is ready for use. In operation, if a songbird of desired weight alights upon perch assembly  23   a,  the perch remains extended outwardly as shown in FIG. 1 allowing the songbird entrance and egress from the opening  22 . However, if an undesirable bird or other pest alights upon the perch assembly  23   a,  the weight of the pest being greater than the elastic limit of the extension spring  26  will then cause the extension spring  26  to elongate and allow the perch sleeve  27  to collapse downwardly thereby dislodging the pest. The proximal contacting surface  32   a  of the spring housing and the proximal contacting surface  32   b  of the perch sleeve are in contact with one another forming a fulcrum when the spring is in the retracted relaxed condition, but when an overweight pest alights upon the perch sleeve  27  the perch sleeve will separate from the spring housing at fulcrum points  32   a  and  32   b  which will act as a fulcrum to permit the perch sleeve  27  to collapse downwardly. 
     Referring now to FIGS. 4 and 5, another embodiment of the birdhouse and perch assembly is shown wherein the perch assembly  23   b  is placed in aperture  24  and generally comprises a generally cylindrical perch  33  wherein the contact point  32   b  abuts against the fulcrum contact point  32   a  of spring housing  34 . Located within the hollow spring housing  34  is a compression spring  35  which terminates in a threaded coupler  37 . Placed within the spring housing  34  is compression spring  35 , and through the center of spring  35  is threaded a flexible cable  36  whose free end  38  is placed within an aperture  39  of perch  33  and then crimped tightly therein. The remote end  41  of flexible cable  36  then bears against compression spring  35 . When an unwanted pest alights upon the perch  33 , the perch will collapse downwardly dislodging the pest and, when such occurs, flexible cable  36  and its terminating end portion  41  will compress the compression spring  35  to allow the collapse of the perch  33 . Once the unwanted pest is dislodged, the weight is obviously removed from the perch and compression spring will then expand to its normal relaxed condition pulling the perch  33  back into battery against spring housing  34 . 
     Referring now to FIGS. 6 and 7, another embodiment of the perch assembly is identified as numeral  23   c.  In this embodiment the perch assembly comprises four (4) separate perches, all of which are designed to collapse downwardly upon the application of the weight of an unwanted pest. The perch assembly  23   c  includes a housing base  42  which encloses the perch assembly  23   c  and maintains the operable parts in the desired relationship. In this particular embodiment, housing base  42  encloses individual perches  43  wherein adjacent pairs of perches  43  are interconnected by respective flexible cables  44   a  and  44   b.  An extension spring  45  interconnects the midpoints of cables  44   a  and  44   b,  and the spring  45  is positioned against spring pre-load rod  46  which is adjustable vertically by a spring adjustment knob  47 . As is seen in FIGS. 9 and 10, the spring  45  is positioned over the pre-load rod  46  so that upon application of adjustment either up or down of the spring adjustment knob  47 , the tension of the spring may be varied to suit the desires of the user to pre-load the spring  45  to accept either a lesser or greater weight of bird alighting upon perches  43 . The proximal ends  48  of the perches  43  will, upon the placement of excessive weight thereon above the desired threshold set into the spring  45 , depress the perches vertically dislodging the pest. The perches in this particular embodiment will collapse about the fulcrum point at the juncture  48  of the perch with the base  42 . 
     In the embodiment shown in FIGS. 8 and 9, which embodiment is similar to the embodiment of FIGS. 1 and 4, it is seen that there is a double perch assembly  23   d  comprising a pair of perches  51   a  and  51   b  which are mounted into aperture  52  within the birdhouse  21 . Interconnecting the proximal distal pivot ends  53   a  and  53   b  of perches  51   a  and  51   b,  it is an extension spring  54  which is housed within spring housing  55 . Spring housing  55  has respective opposing end contact points  56   a  and  56   b  which abut against proximal ends  53   a  and  53   b  of the respective perches. Maintaining the perches to the spring housing are pivot pins  57   a  and  57   b  which project through pivot pin apertures  58   a  and  58   b  of the spring housing, and ultimately through pivot apertures  58   a  and  58   b  of the perches. Again, with this particular embodiment, when an unwanted pest alights upon one or the other of the perches, the perch will collapse downwardly to extend the spring  54  to thereby dislodge the pest and once the pest has been dislodged then the extension spring returns to its normal relaxed length drawing the perches up to a horizontal condition. 
     Referring now to FIGS. 10 and 11, a birdhouse and feeder assembly  21   e  is shown wherein the lower base portion  59  houses the perch assembly  23   e  which show perches  61  projecting angularly from the base  59 . The perches  61  have a curvilinear configuration and are attached to the base by means of pivot pins  62  which project from a mounting surface  59   a  within the base into the proximal ends  61   a  of the perches  61  in a rotatably sufficient manner so that when an unwanted pest alights upon any one of the perches  61 , the perch will immediately collapse downwardly rotating about the pins  62  dislodging the pest. Each of the proximal ends of perches  61  have a spring mounting tab  63  into which an extension spring  64   a  or  64   b,  as the case may be, is positioned and fixed therein. Opposite perches are connected by the same spring, therefore, once one perch depresses the spring elongates and once the weight is removed from the perch the spring then rotates the perch back into battery. In this particular configuration, the perches are designed to allow birds to feed facing the feeder. In the configuration of a birdhouse, the perches allow adequate space for multiple baby birds to take off from the nest at the same time. 
     In FIGS. 12,  13  and  14 , a modified version of the perch assembly of FIG. 10 is shown wherein the angularly mounted perches  61  have distal ends facing one another. The perch assembly  23   f  includes perches  65  which have proximal spring mounting ends  66  which are attached to respective ends of an extension spring  67 , which extension spring will elongate when excessive weight is placed upon one or the other of the perches  65  allowing the perch to collapse and dislodge the pest, and once such is done the extension spring  67  will then return the perch to the normal horizontal position at the front of the birdhouse  21   f.  As seen in FIG. 13, spring  67  resides within aperture  60 . 
     Referring now to FIGS. 15 and 16, a modified arrangement of the feeder and house system of FIGS. 6 and 7 is shown wherein the perch assembly  23   g  includes perches  68  which are flat horizontal planar surfaces that form an annular platform around the feeder  21   g.  Each quadrant of the platform tray  69  is attached to a control arm  69  which, in turn, is attached to the feeder base  71  by a pivot pin  72 . A flexible cable  73  is attached at its respective ends to respective proximal ends to adjacent pairs of control arms and, at the midpoint thereof, there is an extension spring  74  which is attached between the adjustment rod  75  and the respective cable  73 . This particular embodiment operates much in the same manner as previously described in that when an unwanted heavyweight pest alights upon platform  68 , the platform depresses and the spring extends when a specific weight is applied thereto. The springs  74  are adjustable for perceived weight upon the platform  68  by means of the adjustment rod  75 , which operates much in the same manner as the spring adjustment mechanism  47  shown in FIG.  6 . 
     Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, various modifications may be made of the invention without departing from the scope thereof and it is desired, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and which are set forth in the appended claims.