Abstract:
A bird feeder which utilizes a shielding collar that behaves substantially like a universal-joint. The hollow, generally-cylindrical collar surrounds an annular food tray. The collar has a plurality of openings to provide access to the food tray, with a perch rod adjacent each opening. The collar is suspended by a spring means operative to allow the collar to simultaneously tilt, move downwardly and rotate, thus occluding the passage to food whenever the weight and agitated movements of a squirrel are brought to bear upon the collar.

Description:
BACKGROUND OF THE INVENTION 1. Field of the Invention  
         [0001]    My invention relates to bird feeders, and more particularly to improved feeders from which small animals such as squirrels and raccoons successfully steal or eat food. The use of bird feeders as lawn and garden implements has become a widespread hobby for a major part of the consumer public. While most persons who maintain bird feeders intend that only birds will feed from them, it is common for squirrels and raccoons to steal much of the food from such feeders, much to the displeasure of the people who have placed the feeders with intent to attract song birds.  
           [0002]    2. Description of the Prior Art  
           [0003]    There have been many attempts to provide bird feeders with means for preventing squirrels, large birds and the like from gaining access to feed within a feeder. A serious deficiency of many such feeders is believed to result from an insufficient appreciation of the extreme agility and perserverence of squirrels, and similar animals.  
           [0004]    In a number of these feeders ( 5 , 255 , 631 ;  5 , 207 , 181 ;  5 , 195 , 460 ;  5 , 048 , 461 ) a base member which supports a supply of food carries a spring means which supports a secondary masking, or shield member. The masking member is sufficiently above the food supply to allow birds access to the food. Being of relative light weight (1 to 2 ounces), the birds do not compress, or activate, the spring means. Squirrels or like-sized animals, however, have sufficient weight to compress the spring means, thereby lowering the masking member to where it occludes access to the food supply. This form of feeder has the general disadvantage of allowing feeding access from only one elevation, or from one side of a rectangular box like structure, which limits the number of birds which can feed at any one time. This characteristic also limits the viewing opportunity for owners, as the feeder has to be precisely aligned to the viewer for the viewer to see the feeding area, and thus the birds.  
           [0005]    In other prior art feeders ( 5 , 964 , 183 ;  5 , 720 , 238 ;  5 , 375 , 558 ;  5 , 195 , 459 ;  5 , 163 , 382 ;  5 , 156 , 112 ;  4 , 646 , 686 ), a metal or wire sleeve surrounds the sides of a tower. A spring means supports the sleeve relative to the tower at a position such that openings in the sleeve ordinarily register with feed holes in the sides of the tower. If a squirrel or other animal of like weight clings to the sleeve, its weight compresses the spring means, moving the openings in the sleeve downward so they no longer register with the holes in the tower, thus preventing the squirrel from reaching food. This type of feeder depends on the registration and de-registration of pairs of holes. This form of feeder suffers from the disadvantage that it is telescopic in its movements, which means the outer sleeve moves parallel to the inner tower. This telescopic movement tends to bind, or catch, somewhat more easily than is desired. W~hen the mechanism binds, the outer sleeve does not fully drop, or slide all the way downward, which results in the feeding ports not being totally occluded, thus allowing the squirrel an opportunity to feed. Moreover, because of the critical tolerances of the inner and outer sleeves, this binding can occur once the outer sleeve has dropped fully, and has occluded the feeding ports. When binding occurs at this position, the outer sleeve does not spring upward upon departure of the squirrel, thus rendering the feeder useless to birds that subsequently visit to partake of food.  
           [0006]    It is highly desirable that a bird feeder which prevents squirrels from feeding not be disabled from feeding birds if it has been activated to prevent a squirrel from feeding. It is also highly desirable that a bird feeder mechanism operative to prevent squirrel feeding not be damaged if the feeder is knocked or slammed by a larger animal such as a raccoon, and another object of the present invention is to provide such an improved bird feeder.  
           [0007]    Still other prior feeders ( 4 , 030 , 451 ;  4 , 031 , 856 ;  4 , 102 , 308 ) utilize an over-sized dome structure, or inverted dish, to shield a food tray from squirrels; or attempt to fence squirrels out by having a wire mesh surround the food delivery means ( 4 , 434 , 745 ). These feeders have the disadvantage of excluding certain types of desirable birds; and, because of their utilitarian armaments, these types of feeders are deemed aesthetically undesirable by a large segment of the public.  
         SUMMARY OF THE INVENTION  
         [0008]    One general object of the invention is to provide a bird feeder which is attractive to many birds, but which does not often lose its contents to a very diligent and extremely agile squirrel. One of the primary attending objects of the present invention is to provide a bird feeder which will more effectively prevent squirrels and raccoons from feeding from the feeder. Another more specific object of the present invention is to provide a bird feeder wherein the forces which a squirrel or like animal imparts to the operative food-denying mechanism of the feeder operate in complex manners, through plural or even infinite degrees of mechanical freedom, so that a squirrel or like animal cannot learn how to defeat the mechanism and steal food from the feeder. As will be seen, the present invention utilizes a shielding mechanism that behaves in a fashion substantially like a universal-joint. It is believed that no other prior feeders employ this universal-joint type of mechanism. Other objects will be mentioned below, or will become obvious as the description proceeds. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a side elevation view of a preferred embodiment of the invention.  
         [0010]    [0010]FIG. 2 is a sectional elevation view taken at lines  2 - 2  in FIG. 1.  
         [0011]    [0011]FIG. 3 is a section view taken at lines  3 - 3  in FIG. 2, with parts shown in the normal relative or rest positions they occupy in the absence of a squirrel or similar animal.  
         [0012]    [0012]FIG. 4 is a section view similar to FIG. 2, but with certain parts displaced from their normal relative positions in a manner which occurs if a typical squirrel or similar animal engages the feeder in an attempt to extract food therefrom.  
         [0013]    [0013]FIG. 5 a  is a diagrammatic downward view taken at lines  5   a - 5   a  in FIG. 2; and FIG. 5 b  is a diagrammatic side view useful in understanding some operative aspects of the invention.  
         [0014]    [0014]FIG. 6 a  is a side elevation view illustrating one possible modification in the apparatus of FIGS.  1 - 4 ,  5   a  and  5   b.  FIG. 6 b  is an enlarged view of a detail area of FIG. 6 a.    
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]    Referring now to the drawings of FIGS.  1 - 4 , the bird feeder therein shown will be seen to comprise a hollow cylindrical tube  10  having a top hanger loop  11  by which the entire feeder assembly readily may be pendulously suspended, typically from a tree limb. The feeder is shown as including an upper cover member  12  in the form of an inverted dish having a truncated spherical configuration. Cover member  12  has a substantial radius, so that rain running off the cover will not enter feed tube  10 , and, importantly, so that a squirrel supporting itself atop cover member  12  cannot possibly reach around a circular edge  12   a  into the upper end of feed tube  10 . In one embodiment tube  10  has an outside diameter of 4.00 inches (10.16 cm.) and a length of 15 inches (38.1 cm.), though such dimensions are not in any sense critical. In the preferred embodiment the tube  10  was constructed of transparent plastic having a wall thickness of approximately one-sixteenth inch (0.16 cm.). It is believed to be highly desirable that all or much of the wall of tube  10  be transparent, thereby to exhibit substantial quantities of feed to birds.  
         [0016]    As seen in FIGS. 2 and 3, an integral base  11   a , of hanger loop  11  has a central threaded hole which aligns with a central hole in cover  12 . A second wire loop  13  has a threaded end which screws into threaded hole in base of hanger loop  11 . A washer  14  and a locking nut  38  clamp cover  12  to loop  11  when threaded end of second loop  13  is screwed into threaded hole in base of hanger loop  11 . Second loop  13  extends to engage a wire  15  connected across the upper end of feed tube  10 , thereby pendulously supporting tube  10  and anything attached to it via hanger loop  11 . While a squirrel cannot readily gain access to the upper end of tube  10 , it will be seen that most humans could readily lift and tilt tube  10  in order to remove it for refilling, and then again to replace it.  
         [0017]    As best seen in FIG. 2, an annular seed funnel  32  is shown inserted into lower end portion of cylindrical tube  10 . Funnel  32  and tube  10  are locked together with a first plastic fastener  39   a  and a second plastic fastener  39   b . An annular food tray  31  is shown having a central post member  31   a  which is inserted through a central hole in lower end of funnel  32 . Feed tray  31  and funnel  32  are locked together by a first protruding lower end  37   a  and a second protruding lower end  37   b  of a wire bracket  37 . A plastic cap  40  fits onto top portion of central post member  31   a . Though not shown, the bird food that is poured into tube  10  will flow by gravity downward into top portion of funnel  32 , and thence downward through a plurality of feed slots  32   a  and  32   b  into the annular trough area of food tray  31 .  
         [0018]    As will be seen in drawings of FIGS.  1 - 4 , an annular collar  20  surrounds the lower portions of feed tube  10 , funnel  32  and food tray  31 . Collar  20  has a plurality of holes  23   n ,  23   s ,  23   e  and  23   w  which are positioned directly above an equivalent plurality of perches, respectively  21   n ,  21   s ,  21   e  and  21   w . As seen in FIGS. 2 and 3, each perch is attached to collar  20  by a locking nut, respectively  21 ( 1 ),  21 ( 2 ),  21 ( 3 ) and  21 ( 4 ). The lowermost portion of collar  20  is bisected by a cross bar  22 .  
         [0019]    As shown in FIG. 3, a spring means  26  attaches to the central portion of cross bar  22 , thus suspending collar  20  in a universal-joint fashion to allow pivoting or tilting in any direction relative to axis zz.  
         [0020]    As shown in FIG. 4, with the spring mounting shown, the collar can tilt with perch  21 n moving downward while perch  21   s  moves upward; alternatively, perch  21   e  might be moved downward while perch  21   w  moves upward. And of course, the pivoting can occur at any angle in between the cardinal points mentioned. This type of tilting, which is substantially like the manner of tilting as imparted by a universal joint, is not believed to exist in any prior feeders. Because the angle of this tilting is unpredictable, it is thought to better disorient, and thus better discourage, squirrels.  
         [0021]    As best seen in FIGS.  2 - 4  and FIG. 5 b , collar  20  is shown to have a rolled top edge  20   a  that is curled inward towards the center. This rolled edge facilitates both the tilting and downward translation of collar  20 . As best seen in FIG. 4, this rolled edge also serves to create a seal between the top edge of collar  20  and the lowermost edge of tube  10 , thereby preventing a squirrel or other animal from clinging to a perch such as  21   n  and stealing food by reaching over the top of collar  20  and down into food tray  31 .  
         [0022]    As shown in FIG. 3, collar  20  also may be seen to be rotatable about axis zz. Inasmuch as spring  26  acts as a theoretical long spring, it allows collar  20  to rotate in any direction. This rotation is not believed to exist in any prior feeders. This provides another element of unpredictability which is believed to further disorient and thus deter squirrel activity.  
         [0023]    As best shown in FIG. 4, the spring suspension of collar  20  also allows substantial lineal translation of said collar relative to the rest of the feeder assembly. The distance of lineal translation is governed by a wire stop  29 . This lineal translation provides another degree of unpredictable movement, which further enhances the effectiveness of the feeder&#39;s overall squirrel deterrency.  
         [0024]    As best seen in FIG. 3, bar  22  extends through opposing holes in lower portion of collar  20  and lower looped ends of wire stop  29  and spring  26 . Bar  22  is held in place by a locking clip  24 . Tension of spring  26  holds bar  22  flush against the flat underside of food tray  31 . Bar  22  and collar  20  are thus suspended, or dangled, in a relative fixed position.  
         [0025]    Because the initial tension (approximately 24 ounces) of spring  26  exceeds the combined weight of collar  20 , bar  22  and perches  21   n ,  21   s ,  21   e  and  21   w , (approximately 12 ounces total) by a ratio of 2-1, the collar remains substantially fixed, or stationary, when used by a plurality of small songbirds (approximately 1 ounce or less each) for which it is designed. However, the weight of a squirrel (approximately 22 ounces each), when added to the weight of collar  20 , bar  22  and perches  21   n, s, e  and  w,  is sufficient to overwhelm the initial tension of the spring. Upon the added weight of the average squirrel, the spring deflects, thus allowing the collar to tilt and move downwardly in simultaneous fashion, thereby occluding the feeding ports. In this manner, the squirrel is prevented from taking food.  
         [0026]    Although spring  26  is shown as a coil type which ordinarily has an initial tension, the invention could instead utilize various other types of springs, including ones with coils that have space between their turns, as well as flat springs and other non-coil types of springs.  
         [0027]    Referring now to diagrammatic FIG. 5 b , the food tray  31 , wire bracket  37  and cylindrical tube  10  and no other parts shown in FIG. 5 b  will be referred to as being stationary. Similarly, in FIG. 5 b  spring  26 , wire stop  29 , collar  20 , cross bar  22  and perches  21   n ,  21   e  and  21   s  will be referred to as being moveable. Collar  20  is not only tiltable relative to the vertical central axis z-z of the stationary tube  10 , and rotatable about said axis, but also translatable downwardly along said axis. This complexity of movements of all moveable parts relative to the stationary parts is not believed to exist in any prior feeders. Moreover, this complexity is believed to provide much enhanced squirrel deterrency.  
         [0028]    In FIG. 5 b  a dashed-line f is shown extending from the top of hole  23   n  of collar  20  to a point near the middle of feed tray  31 , and a dashed-line g is shown extending from the bottom of hole  23   n  across top of an outer wall  31   d  of tray  31  to terminus of dashed-line f. Lines f and g thus define, in a two-dimensional sense, and with some approximation, the size of the passage through which a bird located outside the feeder might reach with its beak in order to take food (not shown) out of the annular trough area of feed tray  31 , if the bird did not apply substantial downward weight to perch location  21   n . Line f is shown terminating somewhat short of the central post member of tray  31  because the usual bird for which the feeder is intended may not have a beak long enough to reach that central post.  
         [0029]    A respective opening shown as comprising a circular hole is provided in collar  20  above each perch location, three such holes being shown in FIG. 5 b  at  23   n ,  23   e  and  23   s . As best seen in FIG. 5 b,  collar  20  is suspended from the stationary structure of cylinder  10  by coil spring  26 , one end of which is shown attached to wire bracket  37 , and the other end of which is shown fixedly attached to bar  22  on collar  20 . Wire stop  29  is shown with an upper, extended loop end attached to wire bracket  37 , with the opposing loop end attached to bar  22  on collar  20 . The middle portion of wire stop  29  can be seen to extend down through the center of spring  26 .  
         [0030]    In FIG. 5 a  perches  21   n ,  21   s ,  21   e  and  21   w  are shown protruding from the cylindrical outer surface of collar  20  so as to provide four perch locations upon which one or more birds may perch. A cardinal compass-point N, S, E or W meaning North, South East or West is shown adjacent each perch location solely to facilitate discussion. Flat end of bar  22  can be seen protruding from collar  20 , with opposing end of bar  22  held in place with locking clip  24 .  
         [0031]    As shown in FIG. 4, it will be clear that if appropriate downward forces are applied to one or more of the four perch locations, collar  20  may be tilted downwardly not only in any of the four cardinal-point directions, but also in any intermediate direction between any adjacent pair of cardinal-point directions. The passage toward food, as illustrated by dashed-line f and dashed-line g, can be completely occluded, with all of opening  23   n  lowering well below the upper edge of the outer shoulder of tray  31 . It should be noted that the length of the upper loop portion of wire stop  29  limits the distance which collar  20  can translate downwardly.  
         [0032]    Inasmuch as coil spring  26  has numerous turns it acts as a theoretical “long spring” for both translation and rotation. Otherwise stated, (1) the upward force which spring  26  applies to collar  20  varies little percentage-wise between an “unloaded” condition wherein no downward force is applied to any perch location and a “maximum-loaded” condition wherein wire-stop  29  acts as a stop to limit the stretching of spring  26 , and (2) rotation of collar about the z-z axis for even a full turn or  360  degrees or more does not wind-up or unwind spring  26  so as to result in an appreciable spring force affecting rotation.  
         [0033]    It should become apparent at this point that one may easily prevent any spring unwind or windup by merely mounting bar  22  and collar  20  in a rotatable fashion. In FIGS. 6 a  and  6   b , the lower end  26   e  of spring  26  and lower end  29   e  of wire stop  29  is shown passing through a hole drilled in bar  22 , with a crimped fastener  27  staked on end  26   e  and end  29   e , so that bar  22  and collar  20  may rotate relative to end  26   e , end  29   e  and crimped fastener  27  through as many rotations as desired.  
         [0034]    In various embodiments tube  10  may be formed of metal, or glass, or a different plastic. The tube need not be transparent, though many users believe that transparency is advantageous because bird activity tends to be increased if food is visible.