CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The current applications claims the benefit of priority from U.S. provisional patent application filed on Mar. 1, 2005, entitled “Screening Machine With Removable Feed Hopper,” having Ser. No. 60/657,346, which is incorporated herein by reference. 
     
    
     FIELD OF INVENTION  
       [0002]     The invention relates generally to machines used for screening and separating particulate material. In particular, the invention relates to a machine used for separating particulate material of various sizes into separate piles of like-sized material, wherein the feed hopper on the machine is removable.  
       BACKGROUND OF THE INVENTION  
       [0003]     Machines for separating particulate material are known in the art. Oftentimes it is desired to separate materials of different sizes into separate piles, for further processing or disposal. For example, sand or soil and dirt may contain rocks, concrete, asphalt, roots, stumps and other debris. Smaller-dimensioned material, such as sand or soil, can be separated from larger materials by pouring the mixture into a vibrating screen apparatus. The mesh of the screen is sized to allow the smaller-dimensioned material to fall through the screen, and the larger-dimensioned material is retained above the screen. The screening process can be repeated for the smaller-dimensioned material, for the larger-dimensioned material, or both, thus further separating the materials.  
         [0004]     The particulate material that falls through the screen can be collected in a container or, alternatively, the material can drop onto a conveyor and be transported to a container or discharged from the conveyor and onto a pile on the ground. Optionally, the material that falls through the first screen can be caught on a second screen and screened again, thus further separating the particulate material. The material remaining on the first screen can be dropped onto a conveyor and transported to a container or discharged onto a pile on the ground.  
         [0005]     The material to be screened is typically loaded into a hopper that is mounted to the frame of the screening machine, on which the various conveyors are also mounted. Oftentimes, the hopper is positioned above a conveyor, such that material from the hopper falls to the conveyor below, and the conveyor transports the material to the screens. The hopper is often filled from the top by loaders that pour the particulate material into the hopper. It is advantageous to be able to load the hopper from more than one side of the hopper, thus providing more flexibility to hopper and screening machine placement, and allowing for filling by multiple loaders.  
         [0006]     Some of the screening machines are designed to be portable, such that the machine can be moved from worksite to worksite, or to various locations on one worksite. The screening machine may have wheels attached such that it can be towed behind another vehicle. Alternatively, the screening machine can be towed onto a trailer and hauled by trailer to another location. Yet another alternative is for the screening machine to include an endless track apparatus, such that the screening machine can be moved without having to be towed or hauled by another vehicle.  
         [0007]     U.S. Pat. No. 5,234,564 to Smith entitled “Mobile Screen Assembly for Rubble and Debris” appears to disclose a screening machine with a plurality of conveyors that transport particulate material from the hopper to a number of screens and then into separate piles, based upon size of the particulate material. The hopper is supported on” the machine frame and is disposed over a lower inclined portion of the upwardly inclined transport conveyor. The screening machine can be towed by a vehicle over the road or highway.  
         [0008]     U.S. Pat. No. 6,698,594 to Cohen et al. entitled “Screening Machine” appears to disclose a mobile screening machine on endless tracks. A hopper and a main conveyor are mounted to the screening machine frame. A screening device, which is positioned beneath the upper end of the main conveyor and extends further longitudinally along the frame, screens the particulate material into three grades of coarseness. The tracks allow the screening machine to be driven around a work site or driven onto a trailer.  
         [0009]     Although the two screening machines noted above, and other such screening machines, may be able to screen particulate material, the machines have certain disadvantages that will be noted below. There exists a need for a screening machine that overcomes the disadvantages of the prior art.  
       SUMMARY OF THE INVENTION  
       [0010]     Although there exist a number of different types of screening machines, there is a need for a screening machine with a removable feed hopper. Removing the feed hopper allows the screening machine user to feed the screening machine from three sides of the screening machine. In addition, the screening machine can be fed from a conveying device, from earthmoving equipment, or from some other device. Further, removing the feed hopper lowers the receiving height of the screening machine, allowing easier access for loading particulate material onto the screening machine. A removable feed hopper provides versatility and flexibility to the use of the screening machine.  
         [0011]     In a first aspect, the invention relates to an apparatus for screening particulate material comprising an elongated frame comprising a first end and a second end and a feed hopper attached to the first end of the elongated frame comprising a plurality of wall members operably connected to define an interior space adapted to receive particulate matter poured into a top of the feed hopper, a first stationary engagement element and a first pivotal engagement element, wherein the first stationary engagement element and the first pivotal engagement element can couple with corresponding engagement elements on the first end of the elongated frame to reversibly attach the feed hopper to the first end of the elongated frame. In these embodiments, the apparatus can further comprise a screen assembly operably coupled to the second end of the elongated frame comprising a first screen deck including a mesh portion having openings adapted to separate particulate material fed into the feed hopper, and a conveyor operably coupled to the elongated frame and extending longitudinally along the elongated frame to convey particulate material from the feed hopper to the screen assembly.  
         [0012]     In a second aspect, the invention relates to an apparatus for screening particulate material comprising an elongated frame comprising a first end and a second end and a feed hopper attached to the first end of the elongated frame comprising a plurality of wall members operably connected to define an interior space adapted to receive particulate matter poured into a top of the feed hopper and at least one engagement element that is adapted to couple with a corresponding element on the elongated frame to reversibly attach the feed hopper to the elongated frame. The apparatus can further comprise a screen assembly operably coupled to the second end of the elongated frame comprising at least one screen deck having a mesh portion having openings adapted to separate particulate material fed into the feed hopper, and a conveyor operably coupled to the elongated frame and extending longitudinally along the elongated frame to convey particulate material from the feed hopper to the screen assembly.  
         [0013]     In another aspect, the invention relates to a method of operating an apparatus for screening particulate material comprising reversibly attaching a feed hopper to a first end of an elongated frame of a screening apparatus, wherein the screening apparatus comprises a screen assembly operably coupled to a second end of the elongated frame comprising at least one screen deck having a mesh portion adapted to separate particulate material fed into the feed hopper, and a conveyor operably coupled to the elongated frame and extending longitudinally along the elongated frame to convey particulate material from the feed hopper to the screen assembly. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a side perspective view of the screening machine with the feed hopper attached to the machine.  
         [0015]      FIG. 2  is a perspective view of the screening machine with the fold-over receiving hopper attached.  
         [0016]      FIG. 3  is a perspective view of the feed hopper and the screening machine, with the hooks of the feed hopper attached to the screening machine.  
         [0017]      FIG. 4  is a perspective view of the feed hopper and the screening machine, with the hooks of the feed hopper disengaged.  
         [0018]      FIG. 5  is a side elevational view of the feed hopper disengaged from the screening machine.  
         [0019]      FIG. 6  is a perspective view of the feed hopper and the screening machine, with the feed hopper disengaged from the screening machine.  
         [0020]      FIG. 7  is a perspective view of the screening machine without the feed hopper and with the fold-over receiving hopper in storage position.  
         [0021]      FIG. 8  is a side elevational view of the hopper end of the screening machine with the fold-over hopper in operational position.  
         [0022]      FIG. 9  is a perspective view of the feed hopper and the screening machine.  
         [0023]      FIG. 10  is a view of the hydraulic hoses located under the feed hopper. 
     
    
     DETAILED DESCRIPTION  
       [0024]     Referring to  FIG. 1  and  2 , a screening machine  10  is shown in operating configuration, with a feed hopper  20  attached to one end of the main frame  30  of the screening machine. The main frame  30  of the screening machine is elongate and rigid, with the various components of the screening machine  10  connected or attached to the main frame  30 . The screen assembly  40  of the screening machine  10  is attached to the main frame  30  and located at the opposite end of the screening machine main frame  30  from the feed hopper  20 . A belt-feeder  52  is positioned below the feed hopper  20  and conveys material to the main conveyor  50 , which in turn conveys material to the screen assembly  40  of the screening machine  10 . Material at the screen assembly  40  of the screening machine  10  is then separated into three piles of differently-sized particles.  
         [0025]     The feed hopper  20  is located at one end, the proximate end, of the screening machine  10 , parallel to the main frame  30 . Referring to  FIGS. 3 and 4 , further, the feed hopper  20  is attached to the main frame  30  with a series of hooks  22 . In one embodiment of the invention, the feed hopper  20  is attached to the main frame  30  with four hooks  22 . Two of the four hooks  22  are stationary and are fixed to the bottom of the feed hopper  20  (not shown). The remaining two hooks  22  are positioned proximate the middle of the feed hopper  20  and are free to pivot when required to do so. It is understood that the number of hooks  22  can be modified, dependent upon the needs of the equipment.  
         [0026]     Mounted directly below the feed hopper  20  is a belt feeder  52 , which is a variable speed conveyor. The belt feeder  52  is also positioned parallel to the screening machine main frame  30 . The belt feeder  52  receives material that has been dumped into the feed hopper  20  and falls through the bottom of the feed hopper  20 . The belt feeder  52  then conveys this material to the main conveyor  50 .  
         [0027]     The main conveyor  50  is positioned parallel to the screening machine main frame  30 , with the lower end of the main conveyor  50  mounted to the main frame. The main conveyor  50  extends longitudinally uphill and terminates at the screen assembly  40 . The upper end of the main conveyor  50  is mounted to the screen assembly  40  and pivots as the screen assembly  40  angle changes.  
         [0028]     Referring again primarily to  FIGS. 1 and 2 , the screen assembly  40  comprises a two-deck screen configuration, with an upper screen deck  44  and a lower screen deck  46 . Each screen deck  44 ,  46  includes a screen  42 ,  48  designed to separate the particulate material fed into the feed hopper  20 . The two screens  42 ,  48  have a differently sized mesh as compared to one another, such that larger particulate material will be retained on the upper screen  42 , while smaller particulate material will pass through screen  42  and onto the lower screen  48  below.  
         [0029]     The screen assembly  40  is mounted parallel to the screening machine main frame  30  and is positioned downhill, angling down towards the feed hopper end of the screening machine  10 . Hence, the screen assembly  40  is positioned parallel and beneath the main conveyor  50 , inclined downhill, such that the particulate material on the screen assembly  40  travels back towards the feed hopper end of the screening machine  10 .  
         [0030]     Particulate material is discharged from the two-deck screen assembly  40  by way of two stockpiling conveyors  54 ,  56  positioned perpendicularly in relation to the screen assembly  40  and main conveyor  50 . Referring primarily to  FIGS. 1, 2  and  6 , the two stockpiling conveyors  54 ,  56  are located proximate the feed hopper end of the screening machine  10 . Material that is too large to pass through the upper screen deck  44  is discharged on the first stockpiling conveyor  54  and the material is piled on one side of the screening machine  10 . Material that passes through the upper screen deck  44  falls to the lower screen deck  46 . Material that fails to pass through the lower screen deck is discharged on the second stockpiling conveyor  56 . The second stockpiling conveyor  56  is positioned on the opposite side of the screen assembly  40  in relation to the first stockpiling conveyor  54 . Hence, the second stockpiling conveyor  56  discharges intermediate-sized particulate material on the opposite side of the screening machine  10  in relation to the first pile of particulate material discharged by the first stockpiling conveyor  54 .  
         [0031]     An underscreen conveyor  58  is positioned below the screen assembly  40  and is mounted directly to the screen assembly frame  41 . Further, the underscreen conveyor  58  is mounted parallel to the screen frame  41 . Material that passes through both screens  42 ,  48  of the screening assembly  40  drops onto the underscreen conveyor  58 . The underscreen conveyor  58  discharges this smaller-sized particulate material at the back end of the screen assembly  40  end of the screening machine  10 , distal the feed hopper end of the screening machine  10 .  
         [0032]     In use, particulate material is loaded into the feed hopper  20  by a loader or other type of earthmoving device. The feed hopper  20  is loaded through its top and material drops to the belt feeder  52 , which transports the material to the main conveyor  50 . The main conveyor  50  transports the material uphill and discharges the material onto the screen assembly  40 . Material that remains on the upper screen deck  44  is discharged to the ground or into a container on one side of the screening machine  10  by way of a first stockpiling conveyor  54 . Material that passes to the lower screen deck  46  is discharged to the ground or into a container on the opposite side of the screening machine  10  from the first discharged pile. The material from the lower screen deck  46  is discharged by a second stockpiling conveyor  56 . The material that passes through both the upper and lower screen decks  42 ,  48  falls to the underscreen conveyor  58 . The underscreen conveyor  58  discharges this particulate material out the screen end of the screening machine  10 .  
         [0033]     Referring primarily to  FIGS. 1-4 , the screening machine of the invention includes a removable feed hopper  20  and a fold-over hopper  80  that remains attached to the screening machine  10 , even when the feed hopper  20  is attached and operating. Situations may arise where the screening machine  10  is to be used, but the height of the feed hopper  20  makes use of the screening machine  10  in its current configuration difficult or even impossible. Removing the feed hopper  20  lowers the receiving height of the screening machine  10  and allows the screening machine  10  to be fed from three sides. In particular, a lower receiving height is desired when feeding the screening machine  10  from another conveying device or from earthmoving equipment.  
         [0034]     In one embodiment of the invention, the feed hopper  20  is attached to the screening machine main frame  30  with four hooks  22 . Two of the hooks  22  are stationary and fixed to the bottom of the feed hopper  20 . As best shown in  FIGS. 3, 4 ,  6  and  9 , the remaining two hooks  22  are located proximate the middle of the feed hopper  22  and are free to pivot when required to do so. Further, the feed hopper  20  sits on four hydraulic legs  60 . The four hydraulic legs  60  are raised to their maximum height and pinned into position. As the hydraulic legs  60  are raised, the feed hopper hooks  22  are lifted off of securing tubes  62  that are mounted on the screening machine main frame  30 . With the pivoting hooks  22  swiveled up and out of the way, no longer connected to the feed hopper  20 , the feed hopper  20  can be detached from the screening machine main frame  30 .  
         [0035]     Referring to  FIG. 10 , the hydraulic hoses  70  that connect the feed hopper  20  to the screening machine main frame  30  are attached using quick-disconnect fittings. These fittings must be disconnected when removing the feed hopper  20  from the screening machine  10 . Each of the fittings is either a different size or has a different end, so that the hydraulic hoses  70  may be hooked back up in only one configuration. The unique nature of each fitting simplifies the set-up process when re-attaching the feed hopper  20 .  
         [0036]     Once the feed hopper  20  is disengaged from the screening machine  10 , the screening machine  10 , for example, can be driven away from the feed hopper  20  and attached to another feed hopper. Alternatively, instead of attaching another feed hopper  20 , a fold-over receiving hopper  80  already attached to the screening machine can be positioned over the main conveyor  50  and be ready for use. The feed hopper  20  can be attached to another screening machine, since the feed hopper  20  can be used on multiple units without modification. In addition, the disengaged feed hopper  20  can be used as a stand-alone unit, with the addition of a power unit. No external tools are required to disengage the feed hopper  20  from the screening machine  10 .  
         [0037]     As noted above, once the feed hopper  20  is removed, it may be desirous to have another type of hopper attached to the screening machine  10 , so that material can still be loaded for separation. A fold-over receiving hopper  80  can be used in place of the feed hopper  20 . Referring to  FIGS. 1-9 , the fold-over hopper  80  can be attached to the screening machine  10  when the feed hopper  20  is also attached to the screening machine  10 . However, the fold-over receiving hopper  80  is positioned out of the way of the operating screening machine  10  by being folded-over the main conveyor  50 , for example. When the feed hopper  20  is removed, the fold-over receiving hopper  80  is placed into operating position. The fold-over receiving hopper  80  can be fed from three directions, thus making for easy loading of the screening machine  10 .  
         [0038]     The screening machine  10  of the invention is mobile and is mounted to a pair of endless tracks  90 . The tracks  90  are powered by an on-machine engine, which when needed, will move the screening machine  10  in multiple directions. Further, movement of the tracks  90 , and hence the screening machine  10 , can be remotely controlled.  
         [0039]     The embodiments above are intended to be illustrative and not limiting. Additional embodiments are within the claims. Although the present invention has been described with reference to particular embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and the scope of the invention.
The invention relates to an apparatus for screening particulate material comprising an elongated frame comprising a first end and a second end and a feed hopper reversibly attached to the first end of the elongated frame such that the feed hopper can be coupled and uncoupled from the elongated frame. Removing the feed hopper allows the screening machine user to feed the screening machine from three sides of the screening machine. In addition, the screening machine can be fed from a conveying device, from earthmoving equipment, or from some other device. Further, removing the feed hopper lowers the receiving height of the screening machine, allowing easier access for loading particulate material onto the screening machine.