Abstract:
A nest pad for poultry and animals is provided having a plurality of inclined projections extending from its lower surface to register with openings in the support surface of the nest enclosure and removably engage a portion of the support surface via a clamping fit. The inclined projections are arranged in at least two sets, and the direction of inclination of the projections of each such set is opposing and outwardly directed.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to animal and poultry husbandry apparatus and systems, and, more particularly, poultry nesting systems having removable nest pads. 
     A wide variety of apparatus have previously been used for raising poultry and other animals. Using the poultry husbandry technology as the exemplary format in this discussion, it has been suggested to raise egg laying hens, breeder birds and other birds within poultry houses or barns by means of numerous rows of cages or partially enclosed nests for individual birds. Previously, wood shavings, straw and other particulate matter have been placed in the bottom of these nests to simulate the grass of a natural nest and offer some degree of protection for the bird and eggs against abrasion and damage. However, such materials have not been sufficiently sanitary and have required frequent replacement. To minimize the time and effort in replacement and to maintain more sanitary conditions for the poultry and the eggs, artificial nest pads have been used in place of particulate matter. 
     Various different types of artificial nest pads have been used. In general, these pads were formed from deformable or resilient plastic material and had a planar configuration with a plurality of closely spaced projections on the upper surface of the nest pad base, the surface the bird would be in contact with while roosting in the nest. These nest pads were dimensioned so as to closely fit within the nest enclosure and were also often flexible so as to conform to the configuration of the nest floor. In some pads the projections were blunt or round ended soft, rubber cones. In other pads the projections were irregularly oriented, flexible tabs, such as is found in Astro-turf®. In yet other pads the projections were a regular array of flexible tabs arranged in a matrix of tufts. Many pad designs also included flow-through vents, perforations, spacings or holes between some or all of the projections and/or the nest pad base to allow some or all of the debris, manure or moisture to fall through the pad and out of the nest toward an open area below it, as well as to permit air circulation into the nest. U.S. Pat. No. 5,159,896 shows one example of prior nest pads. 
     The nest pads were typically mounted within the nest enclosure on an opened surface support structure, such as a perforated web or wire grid, grill or mesh, forming the nest floor. The openings in the support structure provided greater ventilation, ease of cleaning, and reduced fabrication costs. The support structure was not always flat or horizontally disposed within the nest enclosure. Rather, the support structure typically curved from side to side within the nest enclosure and/or inclined from front to back or from side to side. Such non-horizontal orientations were used, for example, to facilitate the automatic removal of eggs from the nest by encouraging them to gently roll toward an exit from the nest and toward a removal conveyor, often disposed adjacent the nest enclosure. The nest pads have previously been mounted on the support structure so as to closely conform to the orientation of the support structure. 
     However, prior nest pads were not usually permanently mounted to the support structure since, over time, even with flow-through perforations the nest pads became dirty and required cleaning. In general, it has been far easier to reliably clean the nest enclosure and nest pads if the nest pads are removable from the nest enclosure. U.S. Pat. 5,551,460 describes cleaning processes for such nest pads, once removed from the nest enclosure. To some extent, the interior configuration of the nest enclosure does restrict movement of the nest pads within the enclosure and out of it. Unfortunately, the constant movement of the birds into, out of and within the nest enclosure tends to displace the nest pad from its preferred orientation. Over time, the nest pad can even be dragged out of the nest enclosure and onto the poultry house floor or slide into the nest exit intended for eggs, thus clogging the egg removal conveyor. 
     It has been suggested to form a plurality of vertical, cylindrical projections from the lower surface of the nest pad to restrict migration of the nest pad from the support structure. In order to obtain the desired degree of retention security, such prior projections have had to be formed with relatively large dimensions, projecting further vertically and being thicker in cross-section. Doing so, however, made the packaging and shipping of the nest pads more costly since fewer nest pads could be stacked within a given container without having the downward projections of one nest pad crush or be crushed by the upward projections of the adjacent nest pad. Moreover, the larger projection dimensions increased the likelihood that one or more projections would not fully register with a support surface opening and pass through it, thus preventing the nest pad from properly seating within the nest enclosure. Further, with certain types of nest pads creating a select number of such projections could require prohibitively expensive tooling since the projections extending below the nest pad toward the support structure would typically be diverse in nature, typically more rigid, from the upward projections supporting the bird. Finally, while such vertical projections could, when properly seated, restrict sliding of the nest pad relative to the support surface, they were not positively locked to the support surface, at best providing an slidable, interference fit. Thus, they were susceptible to upward force dragging, for example, if a bird&#39;s claw snagged and lifted the nest pad vertically, and had difficulty in maintaining full seating on curved support surfaces. 
     Accordingly, it is an object of this invention to provide an improved nest pad for poultry and animals and an improved arrangement for using such nest pads. Further objects include the provision of a nest pad that is: 
     a. positively locatable with respect to its support structure, 
     b. easy to install and remove from the nest enclosure, 
     c. economical to manufacture and market, 
     d. closely conformable to the support structure configuration, 
     e. biased against unintended unseating from the support structure, 
     f. adaptable to a variety of different support structures and configurations, 
     g. of compact dimension with minimal extension below the pad base, and 
     h. stackable for shipping, storage, packaging or handling without causing significant deformation of the bird supporting projections on the top surface of each nest pad. 
     These and other objects of the present invention are obtained through the provision of a nest pad having a plurality of inclined projections extending from its lower surface to register with openings in the support surface and removably engage a portion of the support surface via clamping fit. The inclined projections are arranged in at least two sets, and the direction of inclination of the projections of each such set is opposing and outwardly directed. 
     Other objects, advantages and novel features of the present invention will be readily apparent to those skilled in the art from the following drawings and detailed description of preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a side view of a nest pad incorporating the present invention. 
     FIG. 2 shows a bottom plan view of the nest pad of FIG. 1 . 
     FIG. 3 shows a cut-away, cross-sectional view of the nest pad of FIG. 1 within a representative nest enclosure. 
     FIG. 4 shows an enlarged cross-sectional view of a portion of the nest pad of FIG. 1 illustrating the retention of the nest pad to the support structure. 
     The drawings are not to scale with respect to each other and repetitious detail, such as vent and tuft patterns, has been shown in dashed lines to preserve clarity of view. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1, which illustrates a preferred embodiment of the present invention, shows a nest pad  10  particularly adapted for use with poultry. Nest pad  10  is preferably formed by injection molding of flexible plastic material and includes a base  12  having an upper surface  14  and a lower surface  16 . Prior to insertion into the nest enclosure, base  12  is, for example, a generally planar, rectangular web having a left side  12   a , a right side  12   b , a front  12   c  and a back  12   d . Flexible upper projections or fingers  8  are formed on upper surface  14  and arranged in a series of tufts  20 . Each of these tufts  20  preferably includes eight upper projections  18  arranged in a generally circular configuration and extending vertically upwards from base  12 . As with prior nest pads, projections  18  can be sufficiently flexible to be crushed downwardly to a degree by bird weight to form a comfortable roosting surface. 
     Vents or perforations  22  are provided in base  12  between tufts  20 , and vents or perforations  24  are provided in base  12  within tufts  20  at the central area of the circle formed by projections  18 . As shown in FIG. 2, in the illustrated embodiment vents  22  are generally rectangular and vents  24  are generally circular. As with vents in prior nest pads, vents  22  and  24  serve to permit air circulation and pass-through of debris and moisture from the nest enclosure to areas below the nest enclosure. 
     Lower surface  16  is formed with a plurality of inclined projections  26  which extend generally downwardly from lower surface  16  when the nest pad is viewed from the orientation of FIG.  1 . Each such inclined projection is, for example, generally cylindrical or slightly conical in shape and integrally molded with base  12 . For ease of molding and/or greater strength, the portion of the inclined projection adjacent lower surface  16  can be slightly thicker in its cross-sectional dimension than the portion of the inclined projection extending downwardly further from lower surface  16 . Preferably, inclined projections  26  are more rigid than projections  18 . 
     In preferred embodiments, inclined projections  26  are arranged into a plurality of sets  28 . Each set is, for example, spaced apart from the other set and associated with a particular side and/or corner of nest pad  10 . The inclined projections of a given set are formed with an angle  30  of inclination or direction  32  of inclination which is directed toward an associated side of base  12  of the nest pad. The angle  30  or direction  32  of inclination of a given set of inclined projections  26  is preferably not the same and diverse from the angle or direction of inclination of a different set of inclined projections within the same nest pad. 
     For example, FIG. 2 shows sets  28   a ,  28   b ,  28   c  and  28   d  of inclined projections  26 . Each set includes six inclined projections  26  spaced apart from each other and arranged in a generally triangular formation associated with the nest pad corners. Sets  28   a  and  28   b  are associated with left side  12   a  in that direction of inclination  32   a  of inclined projections  26  in each of those sets is toward that side. Similarly, sets  28   c  and  28   d  are associated with right side  12   b  in that direction of inclination  32   b  of inclined projections  26  in each of those sets is directed toward that side. Direction of inclination  32   a  is shown as opposite direction of inclination  32   b.    
     In use, nest pad  10  is inserted within nest pad enclosure  40  on top of support structure  42 . Enclosure  40  preferably has a front wall, with an opening therein through which birds enter and leave the nest, and a back wall, with an opening for eggs to leave the nest, connected together by side walls  44   a  and  44   b . In some embodiments the opening for eggs to leave the nest may be in the other walls, according to the inclination of the support surface and the location of the egg removal conveyor (not shown, but conventional in nature). 
     Support structure  42 , is for example formed from a grid of cross-crossing wires  46  extending in a curve  48  between the side walls. Alternatively, the grid may extend as a substantially flat incline. Nest pad  10  is mounted to support surface  42  by placing the nest pad thereon, flexing base  12  such that inclined projections  26  pass through the openings in the support surface formed between wires  46  and then relaxing the flexing force on base  12  to allow inclined projections  26  to engage portions of wires  46  and retain those portions in a clamping-like fit between the inclined projection and lower surface  16 . Forming inclined projections  26  at locations on lower surface  16  where openings in support structure  42  are expected will facilitate this engagement and retention to achieve positive location of the nest pad to the support structure. To the extent there is a degree variance between the actual and expected positions of those openings in the support structure, the inclined nature of projections  26  permits accommodation. 
     Where support structure  42  is curved, inclined projections  26  can thereby retain nest pad  10  in a similarly curved orientation against a predetermined level of removal force, especially since where the flexibility of nest pad  10  is such that it is biased toward a flat orientation, a constant force is exerted by inclined projections  26  toward the portions of wires  46  retained by those projections. In preferred embodiments, this force is directed toward the sides of the nest pad by the orientation of inclined projections  26 . Viewed alternatively, the nest pad exerts a biasing force the urges a portion of the support structure into the clamping engagement with inclined projections  26  and lower surface  16 . When it is desired to remove the nest pads for cleaning, a greater removal force can be exerted or base  12  can again be flexed to withdraw inclined projections  26  from engagement with wires  46 . Similarly, positive location of the nest pad to an inclined support structure is providable. 
     At the same time, by forming projections  26  with an incline, rather than a purely vertical extension from lower surface  16 , the projections can have sufficient length to securely engage support structure  42  and yet minimally intrude upon projections  18  of adjacent nest pads when nest pads are stacked for shipping or storage. Thus, the risk of undesirably deforming projections  18  prior to or between use is reduced without incurring greater shipping or storage costs. Similarly, since a clamping fit is provided, the cross-sectional dimensions of projections  26  can be reduced from those required to maintain an interference fit. Further, since the incline of projections  26  tolerates a wider variety of support structure configurations and dimensional deviations, nest pad  10  can be more versatile in its applications. 
     Although certain preferred embodiments of the present invention have been described above in detail, that is only by way of illustration and example. Those of ordinary skill in the art will now appreciate that modifications and adaptations of this invention can be made to many environments of use and that the vertical and horizontal orientations stated herein are frames of reference only and not application specific requirements. Accordingly, the spirit and scope of the present invention are to be limited only by the terms of the claims below.