Abstract:
An animal feeder for providing feed to animals includes a plurality of side and end walls defining an interior chamber. A perforated plate defines a bottom wall of the chamber and is moveable therein. A grate defines a top wall of the chamber and allows access to feed material contained in the chamber. A spring mechanism biases the plate toward the grate such that feed material located within the chamber is continuously provided to an animal feeding at the level of the grate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/133,978, filed on May 13, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an animal feeder, and in particular, a feeder for continuous clean grazing. 
     2. Description of the Prior Art 
     Grazing in a field is a natural method for feeding farm animals. Throughout history, when grazing in a field was not easily available, animals (hereinafter “horses”) have been fed in stalls or corrals with hay or other feed (hereinafter “hay”) placed in a feed box and the horse is allowed to feed at its leisure. Such hay boxes are nothing more than a containment box with an open top, the opening allowing the horse to reach into the box from the top to get at the hay. 
     Several problems exist with this type of a hay box. First, a significant amount of hay inevitably spills onto the floor of the stall or ground. This loose hay results in a wasting of the hay as feed material, often results in the ingestion of contaminates by the horse as it eats hay from the floor of the stall, and creates additional work in cleaning the stall. An additional problem with prior hay boxes is that as the horse consumes the hay, the horse must continually reach further into the hay box to access the hay. Prior hay boxes also do not restrict the rate at which the horse can consume the hay. If hay is not continuously provided, the horse will often eat at an excessive rate when the hay is initially provided, resulting in potential digestion problems. 
     Improved devices for feeding horses were some of the earliest patented inventions. Initial horse feeders such as in U.S. Pat. No. 195,351 provided for a box with an adjustable bottom to move the food up to the top for the horse to feed so it wouldn&#39;t have to reach further and further down as it consumed hay. This device required manual adjustment of the bottom as the horse consumed the hay. 
     U.S. Pat. No. 763,951 had a spring attached to the bottom of the surface the hay sat on so it would raise as the horse ate. However there was no way to determine, until the hay was gone, how much was left in the box because it was fully enclosed. Further, the bottom surface of the feeder was solid so contaminants, such as sand or gravel were trapped on the bottom surface and consumed by the animal. 
     A further feeder was described in U.S. Pat. No. 1,090,286, which had springs at the top pulling up the feeder as the animal ate the feed. This feeder has the same issues with contaminants and non-visibility of the feed level as U.S. Pat. No. 763,951. Further, it provided no attachment method to a stall wall so the horse could knock it over and eat freely from the floor, thereby consuming contaminants. 
     U.S. Pat. No. 4,294,197 described a horse feeder that could attach to the wall so the horse could not knock it over. However, the feeder was permanently attached to that wall and the bottom surface was still solid, causing contaminants to collect at the bottom of the food supply where the horse might still consume them. 
     From the above discussion, it is clear that the need exists for a hay feeder, which overcomes the above and other limitations of prior hay boxes. It is therefore a primary object of this invention to fulfill that need by providing a device which allows horses to graze on clean hay from a container maintained at a consistent height and which simulates grazing while the horse is contained. 
     SUMMARY OF THE INVENTION 
     Briefly described, these and other objects are accomplished according to the present invention by providing an adjustable spring-loaded hay grazing feeder that maintains the hay at a constant level for the horse to graze on, contains a pressure plate which is perforated to allow sand and other contaminants to fall out of the feeder, has a slot in the side to allow viewing of the amount of hay in the feeder, contains a removable grate so the opening size can be changed for different size horses (e.g. foals, draft horses), has mounting brackets that secure to various walls so the unit is portable and contains an anti-jamming feature by using flared walls at the top. 
     Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the hay feeder; 
     FIG. 2 is a front view of the hay feeder, taken substantially along line  2 — 2  of FIG 
     FIG. 3 is a side view of the hay feeder, taken substantially along line  3 — 3  of FIG  1 ; 
     FIG. 4 is a side view of the hay feeder; 
     FIG. 5 is a top view of the hay feeder; 
     FIG. 6 is an enlarged view of FIG. 2, illustrating the flare at the top of the hay feeder; 
     FIG. 7 is a perspective view of the attaching brackets prior to mounting; and 
     FIG. 8 is a perspective view of the attaching brackets after mounting of the hay feeder. 
     FIG. 9 is a perspective view of a second embodiment of the hay feeder; 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now in detail to the drawings, perspectively shown in FIG. 1 is the hay feeder  8  according to the present invention. The hay feeder  8  consists of opposing side walls  22  and  23  and opposing end walls  28  and  30  with slots  26  cut in them, all supported by corner members  18  and  20 . A removable grate  16  that the horse feeds through is attached to the corner members through attaching pins  32  by a method that will be described later. The hay fits between the grate  16  and a pressure plate  14 , which is the bottom surface of the hay feeder  8 . 
     The pressure plate  14  is better shown in FIG. 2 where the connection to the springs  10  &amp;  12  is demonstrated. A spring  10 , 12  is attached at its bottom to each corner of the pressure plate  14 . The springs  10  and  12  are located within opposing legs of the corner members  18  and  20  and are secured at their top to the corner members  18  and  20 . When there is no force on the pressure plate  14 , the springs  10  and  12  are in their relaxed condition generally as shown in the main view of FIG.  2 . The shadowed view of FIG. 2 shows the springs  10  and  12  fully extended and the pressure plate  14  near the bottom of the hay feeder  8  as if a full flake of hay were inserted into the hay feeder  8 . The hay flake would be compressed between the pressure plate  14  and the grate  16 . As the horse fed, the pressure plate  14  would rise closer to the grate until the hay feeder  8  was empty of hay. 
     One condition that might prevent the hay from rising towards the grate  16  to allow the horse continuous feeding would be if hay, which the animal could not reach, built up beneath the cross members  17  of the grate  16  at the interior edges of the side walls  22  and  23 . The prevention of this potential condition is shown in FIG. 3 where the side walls  22  and  23  flare  42  and  44  outwardly. By flaring outwardly, the hay feeder  8  provides an open space  45  between the side walls  22  and  23  and the hay itself. Because of the composition of the hay, the hay does not expand outward to fill these spaces  45  as it is forced upward. The spaces  45  therefore provides an area allowing the horse to get behind hay at the sides of the hay feeder  8  and eliminate build-up at the side walls  22  and  23  and grate  16  interface and allow the pressure plate  14  to rise. FIG. 6 demonstrates the flares  42  and  44  and spaces  45  in the side walls  22  and  23  in an expanded view. 
     A further concern with the hay level in the hay feeder  8  might be that the hay feeder  8  would be empty of hay before the operator would know to refill it. This could lead to extended periods of time where the animal would have no hay. This condition has been prevented by slots  26  cut into the end walls  28  and  30  as shown in FIG.  4 . The hay and the side surface  24  of pressure plate  14  can be viewed through the slot  26 . When the hay is nearly empty, the side surface  24  will be nearer to the top of the slot  26  as can be seen in the main view. The shadowed view shows the side surface  24  near the bottom of slot  26 , indicating a nearly full hay feeder  8 . This will give the operator warning as to when the feed is getting low so it never needs to be empty. 
     When the feed is empty, the hay flake is inserted through the top of the hay feeder  8 . The grate  16  can be opened from either side of the hay feeder  8  or completely removed to accomplish loading of the hay flake. The attachment of the grate  16  to the comer members  18  and  20  is demonstrated in FIG.  5 . The grate  16  attaches to the corner members  18  and  20  by way of four engaging pins  32  which fit into holes  82 ,  84 ,  86  and  88  in the interior of the corner members  18  and  20  or end walls  28  and  30 . The engaging pins  32  are held to the grate  16  by way of flanges  36  and  38  with the engaging pins  32  inserted through and interacting with coil springs  34  located between the flanges  36  and  38 . The springs  34  act to bias the engaging pins  32  into the holes  82 ,  84 ,  86  and  88 . In this embodiment, a bent end  40  is provided on the inboard end of the engagement pins  32  for easy access to move the engagement pins  32 . The four engagement pins  32  are placed so that any two end-to-end opposing engagement pins  32  may be released from the holes (either  84  and  88  or  82  and  86 ) allowing the grate  16  to be opened from either side (pivoting about the still engaged pins  32 ) for loading a hay flake. The grate  16  is also easily fully removable by releasing all the engaging pins  32  for cleaning or replacing with a grate with wider or narrower spacing between cross-members  17  for different sized horses (foals, draft horses, etc.). After the hay flake is installed, the grate is replaced, the engaging pins  32  are all inserted into holes  82 ,  84 ,  86  and  88 , locking the grate  16  in place and making the hay is ready for the horse to consume. 
     Through the grate  16 , the detail of the perforated holes in the pressure plate  14  can be seen in FIG.  5 . This allows sand and other contaminants to drop out of the hay feeder prior to the horse consuming them. 
     After the hay flake is inserted and the grate  16  is closed, there is still the risk that the horse might knock over the hay feeder, thus contaminating the hay. Bottom attaching brackets  50  and top attaching brackets  62  are shown in FIG.  7 . Fasteners are inserted through holes  52  and  54  in rear legs  58  to attach the brackets  50  and  62  to a stall, trailer or other surface wall to prevent the horse from knocking over the hay feeder  8  and contaminating the hay. The corner members  18  and  20  of the hay feeder  8  slide into these attaching brackets  50  and  62  from above and the comer members  18  and  20  are captured by side legs  56  and front legs  59  of the attaching brackets  50  and  62 , securing the hay feeder  8  to a solid wall surface so a horse can not knock it over. For additional security, knobs  66  are positioned on the top attaching brackets  62  by threaded fasteners protruding from the inboard side of the knobs  66  through the brackets  62 . As the knobs  66  are turned clockwise, the threaded fasteners further protrude inward and contact the corner members  18  and  20  to prevent any looseness in the attachment of the hay feeder  8  to the brackets  62 . Multiple sets of brackets may be installed in various locations such as a stall and a horse trailer and the hay feeder can be carried to each location to reduce duplicative costs. 
     The hay feeder  8  is shown secured to a wall surface in FIG.  8 . The corner members  18  and  20  have been inserted down through the brackets  50  and  62  and the hay feeder  8  cannot be knocked over by the horse, thus keeping the feed accessible and clean. 
     A further embodiment of the invention is illustrated in FIG. 9, where like reference numerals are used to identify corresponding or the same elements in the previously discussed embodiment. 
     This embodiment differs in that the cross members  117  of the grate  116  are not straight throughout their length, as in the embodiment of FIG.  1 . Rather, between the opposing ends  118  of the cross members  117 , a central portion  119  is upwardly raised or peaked relative to the ends  118 . This provides the cross members  117  with a bend between the ends  118 . 
     As the hay is urged upward by the pressure plate  14 , contact with the upward slope of the cross members  117  will cause the hay to move toward the centerline of the hay feeder  8 , as defined by the peak of the central portions  119 . This further insures that hay does not build up beneath the grate  116  because the horse cannot obtain hay immediately adjacent to the side walls  22 ,  23 . Cross members  117  of this variety may be used with or without the flares  44  discussed above. Preferably, they are used with the flares  44 . 
     While the above description constitutes the preferred embodiments of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.