Abstract:
A grain storage safety net system and method is designed to reduce or prevent accidents involving grain carts and grain storage bins. The safety net system includes a strong and durable wide mesh netting which is secured to the inside periphery of either a grain cart or grain bin via a plurality of anchors. The netting thus blankets an upper ingress opening of the cart or bin, with the wide mesh netting allowing the ingress of grain while preventing human entry therein.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a safety net system and method for grain bins and grain carts, and, more particularly, to such a safety net system and method in which a large mesh safety net is attached to anchors positioned along the inside perimeter walls of a grain bin or grain cart such that the net extends over the entire grain storage area of the bin or cart to allow grain ingress while preventing a person from entering the grain storage area. 
     BACKGROUND OF THE INVENTION 
     Grain storage structures, including mobile grain carts and stationary grain storage bins are one of the leading causes of farm deaths in the United States. In 1992, the National Institute for Occupational Safety and Health (NIOSH) reported 9 fatalities in the United States from getting suffocated in grain or caught in grain augers in a bin or cart. The State of Illinois alone reported 22 deaths from grain bins, as well as an additional number from grain carts, in the years from 1986-1994. There are a number of causes for these accidents. 
     When grain is stored with a relatively high moisture content, the grain tends to cake or crust at the surface and form a “bridge” of caked grain which can extend all of the way between the sidewalls of the storage bin or cart. Such bridged grain is extremely hazardous because it prevents grain from flowing into the bin or cart and hides underlying pockets of air beneath the bridge. Farmers will often walk on the bridged grain in an effort to break it up and fall through the bridge, thus getting engulfed in the grain. 
     Farm workers are also often buried by stored grain as the grain is being emptied from the bottom of the bin or cart. The flowing grain acts much like quick sand, pulling the worker completely under the grain surface. According to NIOSH, forces created by a grain auger unloading grain are so great that, once a person is buried up to the waist, they stand virtually no chance of escaping from the auger force, even with the aid of a safety rope. The force required to remove a person buried to the chest in grain can exceed 2,000 pounds, i.e. about the weight of a small car. Typical unloading rates will fully bury an adult person within one minute. High capacity conveyors can move 5,000 bushels of grain in an hour. At these flow rates, a six foot adult will be totally buried in 15 seconds. 
     The risk of suffocation increases as grain ages in a bin due to the emission of carbon dioxide, which displaces the oxygen supply in the bin. Thus, even if a worker is not buried completely, he can suffocate due to the lack of oxygen in the bin. 
     NIOSH recommends the following steps to prevent such accidents, 1) Break up crusts of grain from outside the bin; 2) Avoid entering storage bins or grain carts; 3) If you must enter a bin or cart, stay above the material at all times, assume that all bridged material is unstable, wear safety harnesses with properly fastened life lines, stop the flow of grain prior to entering, and turn on any ventilators 
     It is clear, then, that a need exists for improved safety equipment for grain storage bins and grain carts. Such equipment should preferably be economical and easily installed, yet reliable, should not interfere with operation of the grain cart or bin and should be passive and not easily defeated in purpose. 
     SUMMARY OF THE INVENTION 
     The present invention is a grain storage safety net system and method which is designed to reduce or prevent accidents involving grain carts and grain storage bins. The safety net system is a wide mesh netting which is strong and durable. For example, for grain storage bins, the netting can be made of plastic coated steel cable while for grain carts it might be made of braided nylon or a similar material. The mesh is removably secured to the side walls of the grain storage bin or grain cart via a system of anchors attached about the periphery of the bin or cart. The wide mesh structure of the netting allows grain to freely drop through the netting into the bin or cart, yet prevents a person from intentionally or accidentally entering the bin or cart from above. The inventive method includes the steps of attaching a plurality of anchors to the sides of a grain storage bin or grain cart and then securing a wide mesh netting to the anchors such that it blankets the grain storage area to prevent human entry into the storage area from above, yet allows the free entrance of grain through the netting into the storage area. 
     OBJECTS AND ADVANTAGES OF THE INVENTION 
     The objects and advantages of the invention include: providing a grain storage safety netting system and method; providing such a system and method in which a series of anchors are attached to the inside periphery of a grain storage bin or grain cart; providing such a system and method in which a wide mesh netting is removably secured to the anchors in a position in which the netting blankets the top of the grain storage area of the bin or cart; providing such a system and method in which the netting allows the free ingress of grain into the storage area from above, while preventing human entry into the grain storage area from above; providing such a system and method which minimizes or prevents suffocation accidents involving grain storage bins or grain carts; and providing such a system and method which is reliable, easy to install, is economical to manufacture and which is particularly well suited for its intended purpose. 
     Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. 
     The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of a stationary grain storage bin, with portions broken away to illustrate the placement of a netting system in accordance with the invention. 
     FIG. 2 is a greatly enlarged, fragmentary cross-sectional view of a portion of the grain bin, taken along line  2 — 2  of FIG. 1, and illustrating a side view of one of a plurality of net anchors secured to the corrugated side of the bin. 
     FIG. 3 is a greatly enlarged, fragmentary cross-sectional view of a portion of the grain bin, taken along line  3 — 3  of FIG. 2, and illustrating a top view of the net anchor of FIG. 3 along with a portion of wide mesh safety netting. 
     FIG. 4 is a cross-sectional view of the entire grain storage bin, taken along line  4 — 4  of FIG. 1, and illustrating the complete safety netting and anchor system. 
     FIG. 5 is a perspective view of a mobile grain cart equipped with a grain storage safety netting system in accordance with the present invention. 
     FIG. 6 is a greatly enlarged, fragmentary cross-sectional view of a portion of the grain cart sidewall, taken along line  6 — 6  of FIG. 5, and illustrating a top view of one of a plurality of net anchors secured to the side wall of the cart along with a portion of wide mesh safety netting. 
     FIG. 7 is a greatly enlarged, fragmentary cross-sectional view of a portion of the grain cart side wall, taken along line  7 — 7  of FIG. 6, and illustrating a side view of the net anchor of FIG. 6 with the safety netting secured thereby. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     Referring to the drawings, and particularly FIGS. 1-4, a grain storage safety net system, generally indicated at  1  is attached to a grain storage bin  2 . The safety netting system  1  includes a generally circular wide mesh net  3 , with preferred opening sizes approximately 4″ by 4″. The net  3  is preferably constructed of woven steel cable  4  with a plastic coating  5 . A plurality of net anchors  11  are arrayed about the inside periphery of a cylindrical side wall  12  of the bin  2  about 2-4 feet below a top  13  of the cylindrical side wall  12 . This position allows a person to enter the bin  2  via a ladder  14 , yet the net  3  prevents that person from entering the bin  2  far enough to be immersed in, and therefor suffocated by, a quantity of grain (not shown) stored in the bin  2 . The wide mesh structure of the net  3  allows grain to freely pass through the net  3  but will not allow a person to pass there through. The net  3  is made of a circular peripheral cable  15  and a plurality of attached, criss-crossing cables  16 . 
     FIGS. 2 and 3 illustrate details of one of the net anchors  11 . FIG. 2 shows a number of corrugations  17  of the bin side wall  12 , with the anchor  11  attached thereto. The anchor  11  includes a vertically oriented steel plate  21  of a length to cover a plurality of the corrugations  17 , with a plurality of attachment bolts  22  and nuts  23  extending through the side wall  12  and through the plate  21 . A pair of ears  24  are attached to and extend inward from the steel plate  21  about midway along the plate  21 . The ears  24  are separated by a distance  25  sufficient to easily accommodate a diameter of one of the peripheral cable  15  of the net  3 . Each of the ears  24  has a bore  32  extending vertically therethrough, with the bores  32  being aligned vertically to allow a keeper such as a retention bolt  33  to be placed therethrough inside the peripheral cable  15  to retain the peripheral cable  15  between the ears  24 . A nut  34  is attached to the bolt  33  to hold it in place. 
     Referring to FIG. 4, the anchors  11  thus removably secure the safety net  3  via the peripheral cable  15  in a manner such that it blankets an entire upper opening  35  formed by the cylindrical side wall  12  to prevent human ingress therein. 
     FIGS. 5-7 illustrate a grain storage safety net system, generally indicated at  41 , which is attached to a mobile grain cart  42 . The safety netting system  41  includes a generally rectangular wide mesh net  43 , with preferred opening sizes approximately 3″ by 4″. The net  43  is preferably constructed of attached strands  44  of, for example, braided nylon, but can be made of plastic coated stranded steel cable if additional strength is needed. A plurality of net anchors  51  are arrayed about an inside surface of each of four rectangular side walls  52 - 55 , preferably about 18″ to 24″ below an upper surface of each of the side walls  52 - 55 . Again, this position allows a person to access a generally rectangular top opening  61  of the cart  42 , yet the net  43  prevents that person from entering the cart  42  far enough to be immersed in, and therefor suffocated by, a quantity of grain (not shown) stored in the cart  42 . The wide mesh structure of the net  43  allows grain to freely pass through the net  43  but will not allow a person to pass there through. The net  43  is made of one or more peripheral cable(s)  56  forming a rectangle and a plurality of attached, criss-crossing cables  57 . 
     FIGS. 6 and 7 illustrate details of one of the net anchors  51 . Each anchor  51  includes a vertically oriented steel plate  62  of a length to accommodate a plurality of attachment screws  63  extending through the plate  62  and into the side wall  52 . The plate  62  is bent in the middle to form a semi-circular protrusion  65  which extends inward into the cart  42 . The protrusion  65  forms a recess  71  of a sufficient size to easily accommodate a diameter of the peripheral cable  56  of the net  43 . 
     Referring again to FIG. 5, the anchors  51  thus removably secure the safety net  43  in a manner such that it blankets the entire upper opening  61  formed by the side walls  52 - 55  to prevent human entrance therein while allowing the free flow of grain there through. 
     While certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown. For example, the design of the anchors  11  and  51  is exemplary only and many other variations of attachments could be employed equally effectively. For example, the steel plates could be circular instead of rectangular, which would yield more surface area of attachment. The individual anchors could be replaced with a continuous anchoring system which extends entirely about the periphery of the bin or cart. The anchors  11  and  51  could be reinforced on the opposite side of the respective side walls  12  and  52 - 55 . The nominal mesh opening sizes of the nets  3  and  43  can be any desired dimension, and the net material can be any suitable material as long as the mesh size and material strength are sufficient to prevent human ingress into the grain storage areas of the bin  2  or cart  42 . Other variations will occur to those of skill in the art.