Abstract:
A safety system for reducing the risk of a suffocation accident occurring in a grain bin is disclosed. The disclosed safety apparatus includes an electrical switch in circuit with the motor of an auger mounted in the grain bin for discharging grain therefrom. The switch has a first state wherein the switch prevents operation of the motor and a second state wherein the switch permits operation of the motor. The disclosed apparatus also includes a cover mounted adjacent the access opening for movement between a first position wherein the cover precludes human entry through the access opening and a second position wherein the cover is displaced from the first position. The switch and the cover are positioned to place the switch in the second state when the cover is in the first position and to place the switch in the first state when the cover is displaced from the first position. The apparatus is further provided with a latch for securing the cover in the first position. Additionally, the apparatus includes a spring for biasing the cover toward the second position such that, when the latch and cover are released, the cover moves to the second position and the switch enters the first state to preclude operation of the motor and auger.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to grain bins, and, more particularly, to a safety system for reducing the risk of a suffocation accident occurring in a grain bin. 
     BACKGROUND OF THE INVENTION 
     Grain bins are large, generally cylindrical sheds for storing grain. An exemplary grain bin  10  is shown in FIG.  1 . An auger (not shown) is disposed within the bin  10  adjacent the bottom of the bin  10 . The auger is electrically powered and is run to remove grain from the bin  10  via a discharge opening  12 . When the auger is actuated, the grain inside the bin  10  drains downward in a funnel-like fashion. 
     As illustrated in FIG. 1, grain bins are provided with an access opening  14  in their roofs through which a person may enter the bin  10 . The access opening  14  is usually provided with a hinged door or manhole cover  16  (see FIG. 1) to protect the grain stored in the bin  10  from weather elements such as rain. From time to time, grain can become jammed in the bin  10  such that the auger does not move or, if it moves, little or no grain is discharged. Although it is quite dangerous to do so, individuals sometimes respond to such jamming by entering the grain bin  10  and jumping in the grain to release the jam. Sometimes this process is performed while the auger is supplied with power (i.e., with the auger in the “on” or “run” condition). If a person jumping in the grain releases the jam with the auger in the run state, the auger can start to pull the grain downward in a funnel like manner. If a person is in the grain bin  10  when the grain starts to flow in this manner, they will quickly be pulled under the grain and may subsequently be suffocated. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the invention, a safety apparatus is disclosed for use with a grain bin having an auger, a motor for driving the auger, and an access opening. The safety apparatus includes an electrical switch in circuit with the motor. The switch has a first state wherein the switch prevents operation of the motor and a second state wherein the switch permits operation of the motor. The apparatus also includes a cover mounted adjacent the access opening for movement between a first position wherein the cover precludes human entry through the access opening and a second position wherein the cover is displaced from the first position. The switch and the cover are positioned to place the switch in the second state when the cover is in the first position and to place the switch in the first state when the cover is displaced from the first position. The apparatus is further provided with a latch for securing the cover in the first position. Additionally, the apparatus includes a spring for biasing the cover toward the second position such that, when the latch and cover are released, the cover moves to the second position and the switch enters the first state to preclude operation of the motor and auger. 
     In accordance with another aspect of the invention, a kit is disclosed for use with a grain bin having an auger, a motor for driving the auger, and an access opening for entering the bin. The kit includes an electrical switch adapted to be connected in circuit with the motor to selectively prevent operation thereof. It also includes a cover adapted to be mounted adjacent the access opening of the grain bin for movement between a first position wherein the cover precludes human entry through the access opening and a second position wherein the cover is displaced from the first position. The cover is adapted to disengage the switch to permit operation of the motor when the cover is displaced from the first position and to operatively engage the switch to prevent operation of the motor when the cover is in the first position. The kit is further provided with a latch which is adapted to secure the cover in the first position. Moreover, the kit includes a spring adapted to bias the cover toward the second position such that, when the kit is assembled and mounted to the grain bin and the latch and cover are released, the cover moves away from the first position and the switch precludes operation of the motor and auger. 
     In accordance with still another aspect of the invention, a safety apparatus is provided for use with a grain bin having an auger, a motor for driving the auger, and an access opening. The safety apparatus includes an electrical switch in circuit with the motor. The switch has a first state wherein the switch prevents operation of the motor and a second state wherein the switch permits operation of the motor. The apparatus is also provided with a cover mounted adjacent the access opening for movement between a first position wherein the cover precludes human entry through the access opening and a second position wherein the cover is displaced from the first position. Additionally, the apparatus includes means for placing the switch in the second state when the cover is in the first position and for placing the switch in the first state when the cover is displaced from the first position. The apparatus further includes a latch for securing the cover in the first position. Moreover, the apparatus is also provided with a spring for biasing the cover toward the second position such that, when the latch and cover are released, the cover moves to the second position and the switch enters the first state to preclude operation of the motor and auger. 
     In accordance with still another aspect of the invention, a method is disclosed for reducing a risk of suffocation within a grain bin having an auger, a motor for running the auger, and an access opening. The method comprises the step of mounting a cover adjacent the access opening for movement between a first position wherein the cover precludes human entry through the access opening and a second position wherein the cover is displaced from the first position. It also includes the step of placing a switch in circuit with the motor such that placing the switch in a first operative state precludes operation of the auger and placing the switch in a second operative state permits operation of the auger. The method additionally includes the step of locating the cover and the switch for interaction such that the switch enters the first operative state when the cover is displaced from the first position. Further, the method includes the step of biasing the cover toward the second position such that the auger cannot be operated unless the cover is secured in the first position. 
     Other features and advantages are inherent in the disclosed apparatus or will become apparent to those skilled in the art from the following detailed description and its accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration of an exemplary grain bin having an access opening with the manhole cover in the open position. 
     FIG. 2 is a plan view of a safety system constructed in accordance with the teachings of the instant invention and shown mounted adjacent the access opening within a grain bin such as the bin shown in FIG.  1 . 
     FIG. 3 is a schematic illustration showing the electrical connection of the safety system of FIG. 2 to the circuit supplying power to the auger of the grain bin. 
     FIG. 4 is a view similar to FIG. 2, but illustrating the access opening with the cover of the safety system of FIG. 3 in an exemplary opened position. 
     FIG. 5 is an enlarged view of the switch and spring mechanism of the safety system shown in FIG.  2 . 
     FIG. 6 is a plan view of an access opening such as that shown in FIG. 1, and illustrating the cover of the safety system in an exemplary closed position. 
     FIG. 7 is a view similar to FIG. 6, but showing the cover of the safety apparatus in an opened position. 
     FIG. 8 is a view similar to FIG. 7, but showing the manhole cover in the closed position with the safety cover in the opened position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A safety apparatus  20  constructed in accordance with the teachings of the invention is shown in FIG.  2 . The illustrated apparatus  20  is shown mounted within the grain bin  10  of FIG. 1 adjacent the access opening  14 . While in this detailed description and the accompanying drawings, the apparatus  20  is discussed and illustrated as being mounted within a particular type of grain bin, persons of ordinary skill in the art will readily appreciate that the teachings of the invention are in no way limited to any particular environment of use. On the contrary, the teachings of the invention may be applied in any environment which would benefit from the enhanced safety it provides. 
     For the purpose of substantially rendering the auger (not shown) of the grain bin  10  inoperative, the safety apparatus  20  is provided with an electrical switch  24 . As shown in FIG. 3, when the apparatus  20  is in use, the electrical switch  24  is preferably connected in circuit with both a power supply  26  and an auger motor  28 . When supplied with power by supply  26 , and when actuated by an on-off switch  29 , the auger motor  28  drives the auger to discharge grain from the grain bin  10  as explained above. In the illustrated embodiment, the electrical switch  24  is a contact switch that has an opened position wherein the switch  24  prevents power flow from the power supply  26  to the auger motor  28  to thereby render the auger inoperative, and a closed position wherein the switch  24  permits power flow from the supply  26  to the auger motor  28  to thereby enable operation of the motor  28  upon closure of the on-off switch  29 . 
     In the example of FIG. 3, the switch  24  is connected in series with the supply  26  and the motor  28 , and is located between those two elements  26 ,  28 . However, persons of ordinary skill in the art will readily appreciate that other circuit arrangements can be employed without departing from the scope or spirit of the invention. By way of example, not limitation, the positions of the switch  24  and the auger motor  28  may optionally be reversed in FIG. 3 without departing from the scope or spirit of the invention. By way of another example, not limitation, the switch  24  can be coupled in parallel with the motor  28  to divert power away from the motor  28  to another (lower impedance) element such as an indicator light which illuminates to indicate that the auger is inoperative without departing from the scope or spirit of the invention. 
     Persons or ordinary skill in the art will also appreciate that, while in the illustrated example, the power supply  26  is implemented by a commercial three-phase supply (e.g., a public electrical utility company), other power supplies (either AC or DC) can be used in this role without departing from the scope or spirit of the invention. Of course, the auger motor  28  should either be adapted to use with the selected supply, or appropriate voltage level converting and/or rectification or DC-AC converting circuitry (not shown) should be used to render the motor  28  usable with the selected supply  26 . 
     In order to prevent humans from entering the grain bin  10  through the grain bin opening  14  when the auger motor  28  is operable, the safety apparatus  20  is further provided with a cover  30 . The cover  30  is mounted adjacent the access opening  14  for movement between a closed position such as that shown in FIG. 2 wherein the cover  30  precludes human entry through the access opening  14 , and an opened position such as that shown in FIG. 4 wherein the cover  30  is displaced from the closed position to permit human entry to the grain bin  10  through the opening  14 . 
     Although persons of ordinary skill in the art will readily appreciate that the cover  30  can be implemented in many ways without departing from the scope or spirit of the invention, in the illustrated embodiment the cover  30  is implemented by a mesh screen  32  and a main support arm  34 . The screen  32  is mounted to the main support arm  34  by conventional fasteners  36  such as the clamps  36  shown in FIG.  2 . The main support  34  includes a free end  38  and a secured end  40 . The secured end  40  is pivotably mounted (either directly or through another element such as a mounting plate  42 ) to the grain bin  10 . Therefore, the main support arm  34  and, thus, the screen  32  are mounted within the grain bin  10  for pivoting movement between the opened and closed positions in a plane which is substantially parallel to the access opening  14 . 
     While it will be appreciated by persons of ordinary skill in the art that the mesh screen  32  can be implemented in various ways without departing from the scope or spirit of the invention, in the illustrated example the screen  32  is substantially rigid and is implemented by expanded metal. Similarly, while the main support arm  34  and the fasteners  36  can be implemented in many ways without departing from the scope or spirit of the invention, in the illustrated example the main support arm  34  is implemented by square tube steel and the fasteners are implemented by 2{fraction (5/16)} inch bolts and washers. Finally, although the hinge coupling the main support arm  34  to the mounting plate  42  can also be implemented in many ways without departing from the scope or spirit of the invention, in the illustrated example, it is implemented by providing the secured end  40  of the main support arm  34  with a cylindrical bore (not shown) which is sized to slidably receive a hinge pin  43 . As most easily seen in FIG. 5, the hinge pin  43  is mounted to, and projects outwardly from, the mounting plate  42 . The bore in the secured end  40  of the main support arm  34  mates with the hinge pin  43  such that the main support arm  34  can be pivoted about the pin  43 . Two washers or bearings  44  are also disposed on the hinge pin  43 , one on each side of the main support arm  34 . As shown in FIG. 5, the hinge pin  43  includes a bore. A cotter pin  46  is removably secured in this bore to ensure the main support arm  34  and the washers  46  do not slide off of the hinge pin  43  during use. 
     In order to ensure the auger motor  28  is not operable when the cover  30  is in the opened position and is operable when the cover  20  is closed, the apparatus  20  is further provided with means for placing the switch  24  in the closed state when the cover  30  is in the closed position and for placing the switch  24  in the opened state when the cover  30  is displaced from the closed position. While persons of ordinary skill in the art will readily appreciate that the placing means can be implemented in many ways without departing from the scope or spirit of the invention, the placing means is preferably implemented by a projection  48  which is operatively coupled to the cover  30  in a position to operatively engage the switch  24  to place the switch in the closed state when the cover enters the closed position. 
     More specifically, as mentioned above, the switch  24  is preferably implemented by a contact switch. The projection  48 , on the other hand, is preferably mounted to pivot with the main support arm  34  and is preferably located to engage the switch  24  only when the cover  30  is closed. In the illustrated example, the apparatus  20  includes a supplemental support arm  60  which is coupled to the main support arm  34 . As shown in FIG. 5, the supplemental support arm  60  is secured to the main support arm  34  such that the arms  34 ,  60  are generally perpendicular. A threaded bore  64  is defined near the lower end of the supplemental support arm  60 . The projection  48 , which is implemented in this example by a bolt, is threaded into the bore  64  such that the projection  48  extends outward from the supplemental support arm  60  in a plane generally parallel to, but displaced from, the plane of the main support arm  34 . Since the projection  48  is threaded, the distance it extends from the supplemental support arm  60  can be easily adjusted by threading the projection  48  further into or out of the bore  64  to thereby ensure the projection  48  depresses the contact switch  24  sufficiently to close the switch  24  when the cover  30  enters the closed position but does not depress the switch sufficiently to enter the closed state until the cover  30  enters the closed position. 
     Since the placing means is preferably implemented by a projection  48  which selectively depresses a switch  24 , persons of ordinary skill in the art will readily appreciate that, in the preferred embodiment, the switch  24  is spring biased toward the opened stated in a conventional manner. In view of this preferred mode of operation, persons of ordinary skill in the art will readily appreciate that, as used herein the term “placing” includes both active placing (i.e., acting upon the switch  24  to change its state) and passive placing (i.e., disengaging the switch  24  to permit another element such as a spring to change the state of the switch  24 ). 
     Moreover, although in the preferred embodiment the placing means is implemented by a projection and the switch  24  by a contact switch, persons of ordinary skill in the art will readily appreciate that other equivalent structures can be employed as the placing means without departing from the scope or spirit of the invention. By way of examples, not limitations, the placing means can be implemented by a sensor for detecting the position of the cover  30  and a logic circuit (programmable or hard wired) in communication with the sensor for changing the state of the switch  24  based on the output of the sensor. Various known sensors can be implemented in this role. By way of example, not limitation, the sensor can be implemented by an optical sensor wherein a beam of light directed toward the sensor is occluded when the cover  30  enters a predefined position (e.g., the closed position), or by an inductive sensor which senses the position of the cover  30  by sensing a magnetic field (generated, for example, by a permanent magnet mounted on a portion of the cover  30 ) without departing from the scope or spirit of the invention. 
     To define the closed position of the cover  30 , the apparatus  20  is further provided with a catch  65  which is secured to the bin  10  by conventional fasteners such as bolts. As shown in FIGS. 2 and 4, the catch  65  is located near the corner of the access opening  14 . In the illustrated example, the catch  65  is implemented by a metal arm that has a first portion mounted to the grain bin  10  and a second portion separated from the grain bin  10  to defme a receiving channel therebetween. As shown in FIG. 2, the catch  65  prevents the cover  30  from pivoting downward past the closed position and defines one limit on the range of motion of the main support arm  34 . Since the catch  65  receives part of the screen  32  within the channel, the catch  65  also functions to provide further support for the screen  32  when the cover  30  is in the closed position. 
     Although the preferred embodiment employs the catch  65  as described above, in a less preferred alternative, the catch  65  is eliminated and the apparatus  20  is provided with a stop member  68  to define the closed position of the cover. As shown in FIG. 5, in the illustrated example, the stop member  68  is implemented by a threaded bolt which mates with a threaded bore  70  defined in the supplemental support arm  60 . As also shown in FIG. 5, the stop member  68  extends from the supplemental support arm  60  by a distance sufficient to ensure the stop member  68  engages a side of a switch housing junction box  72  to stop the cover  30  in the closed position. The engagement of the stop member  68  and switch housing  72  prevents the cover  30  from pivoting downward past the closed position and defines one limit on the range of motion of the main support arm  34 . Persons of ordinary skill in the art will appreciate that, in the preferred embodiments employing the catch  65 , the stop member  68  is superfluous and is not included in the apparatus  20 . 
     For the purpose of biasing the cover  30  away from the closed position (e.g., toward the opened position), the apparatus  20  is further provided with a spring  76  which is operatively coupled between the grain bin  10  and the main support arm  34 . As most easily seen in FIG. 5, the illustrated spring  76  is not directly coupled to either the grain bin  10  or the main support arm  34 . Instead, the spring  76  is coupled to the main support arm  34  by a chain  78  and to the grain bin  10  via the mounting plate  42 . More specifically, in the illustrated embodiment, a first end of the spring  76  forms a hook which is coupled to the shank of a bolt  80  which secures the mounting plate  42  to the grain bin  10 . The other end of the spring  76  forms a hook which is coupled to a link of the chain  78 . As also shown in FIG. 5, the end of the chain  78  opposite the spring  76  is secured to a closed loop mounted on the main support arm  34 . The length of the chain  78  and the spring  76  are selected such that, absent application of a restraining force to the cover  30 , the force developed by the spring  76  will pivot the cover  30  out of the closed position sufficiently to ensure the switch  24  enters its opened state to preclude operation of the motor  28  and, thus, to preclude operation of the auger. 
     From the foregoing, persons of ordinary skill in the art will appreciate that the disclosed apparatus  20  ensures that the auger cannot be run unless the cover  30  is in its closed position. Such persons will further appreciate that, since the spring  76  biases the cover  30  away from the closed position, unless the cover  30  is secured, it will not remain in the closed position and the auger will be disabled. Therefore, to enable securement of the cover  30  in the closed position, the apparatus  20  is provided with a latch  84 . Although persons of ordinary skill in the art will readily appreciate that the latch  84  can be implemented in many ways without departing from the scope or spirit of the invention, in the illustrated example shown in FIG. 6, the latch  84  is implemented by a chain  86 . One end of the chain  86  is mounted to a surface of a raised lip  91  formed around the access opening  14  of the grain bin  10 . The opposite end of the chain  86  is free and can be selectively secured to a fastening member  88  mounted on an exterior surface of the cover  30 . More specifically, the free end of the chain  86  preferably includes a hook  90  or the like which can be engaged with the fastening member  88  to secure the cover  30  in the closed position. As shown in FIG.  6 , in the illustrated example, the fastening member  88  is mounted to the main support arm  34 . 
     To prevent an individual from frustrating the safety apparatus  20  by entering the grain bin  10  and latching the cover  20  in the closed position, the fastening member  88  is preferably located near the center of the cover  30  such that a person in the bin  10  cannot activate the latch  84  to hold the cover  30  in the closed position. If an individual attempts to hold the cover  30  shut (or close the switch  24  by hand) to run the auger while he/she is in the bin  10 , when and if the grain starts funneling out of the bin  10 , the individual will be pulled away from the cover  30  (or switch  24 ). Because the individual will then release the cover  30  (or switch  24 ) and because the latch  84  is not secured, the spring  78  will immediately move the cover  30  out of the closed position to thereby immediately cut the power supply to the auger motor  28 . In view of this quick response, the auger will typically stop running before the individual is drawn under the grain and suffocated. 
     As mentioned above, the cover  30  is preferably mounted within the grain bin  10 . This positioning is preferred to ensure the cover  30  does not interfere with the closing of the hinged door or manhole cover  16  which protects the stored grain from weather elements (see FIGS.  7  and  8 ). 
     Persons of ordinary skill in the art will readily appreciate that, while the illustrated cover  30  is mounted within the grain bin  10  for movement in a plane that is generally parallel to the plane of the access opening  14 , other locations and/or mounting arrangements may be employed without departing from the scope or spirit of the invention. By way of example, not limitation, the cover  30  can be mounted outside of the grain bin without departing from the scope or spirit of the invention. By way of further examples, not limitations, the cover  30  can be mounted to pivot into the grain bin  10  or out of the grain bin  10  without departing from the scope or spirit of the invention. 
     Persons of ordinary skill in the art will readily appreciate that many existing grain bins could benefit from being retrofitted with a safety apparatus constructed in accordance with the teachings of the invention. To this end, a kit can be provided including the components needed to retrofit existing grain bins. Such a kit would preferably include a switch  24 , a cover  30 , a latch  84  and a spring  76  as described above. Preferably, the kit also includes the mounting plate  42 . Preferably, some or all of the switch  24 , the cover  30  and the spring are at least partially pre-mounted to the plate  42  to facilitate rapid installation. 
     A person could then use the kit to reduce the risk of suffocation in a grain bin by mounting the mounting plate  42  and, thus, the cover  30  to the grain bin  10  such that the cover is disposed adjacent the access opening  14  for movement between the opened and closed positions. The installer would then connect the switch  24  in circuit with the auger motor  28  such that opening the switch precludes operation of the motor  28  as explained above. The cover  30  and the switch  24  are located to interact such that the switch opens when the cover  30  is not in the closed position. As explained above, the cover  30  is biased away from the closed position such that the auger cannot be operated unless the cover  30  is secured in the closed position. 
     Although certain examples of apparatus constructed in accordance with the teachings of the invention have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the invention fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.