Abstract:
A method and apparatus is disclosed for distributing material onto a surface. The method includes the steps of grinding the material and spreading the material onto a surface. The truck grinder and spreader apparatus has a grinding mechanism for grinding material after it is discharged from a conveyor within a truck body and has a spreading mechanism for distributing the material that has passed through the grinding mechanism onto a surface. The grinding mechanism reduces the size of discharged materials to a predetermined maximum size, and thus prevents the spreading of undesirably large pieces of material. The truck body may include a tailgate that is movable between an open position and a closed position such that when the tailgate is in the open position, material can be discharged from the truck body. The truck may also include a screen positioned atop the truck body for screening the material that is loaded into the truck body.

Description:
BACKGROUND  
       [0001]     1. Technical Field  
         [0002]     The present disclosure generally relates to a method and apparatus for grinding and spreading material from trucks onto a surface. The disclosure has notable utility in trucks of the type having a truck body with a conveyor for conveying the material contents of the truck body rearwardly and into a grinding mechanism prior to discharging the contents at the rear end of the truck body.  
         [0003]     2. Background of Related Art  
         [0004]     Trucks equipped with spreading mechanisms for distributing materials onto a paved surface are generally known. Certain materials to be spread on pavement, however, clump or agglomerate when stored, especially in the presence of moisture. One such material is sodium acetate, a material frequently spread on airport runways to reduce icing. Discharge of large chunks of material is undesirable. Also, large agglomerations of material can block or clog up the spreading mechanism within the truck.  
         [0005]     It would be advantageous to provide a method for efficiently and effectively spreading material of the type that have a tendency to clump or agglomerate and a truck that includes a spreading mechanism for such materials that overcomes these problems.  
       SUMMARY  
       [0006]     A method for distributing material onto a surface, including the steps of grinding the material and spreading the material is provided. A truck grinder and spreader apparatus having a grinding mechanism for grinding material after it is discharged from a conveyor within a truck body and having a spreading mechanism for distributing the material that has passed through the grinding mechanism onto a surface is also provided. The grinding mechanism reduces the size of discharged materials to a predetermined maximum size. The introduction of the grinding mechanism prevents the spreading of undesirably large pieces of material. The grinding mechanism and the spreading mechanism are discussed in detail below.  
         [0007]     The truck body can include a rear tailgate. When the rear tailgate is closed, the material is maintained within the truck body. The opening of the rear tailgate allows the material to be dispensed out the rear of the truck body and onto the grinding mechanism. In one version the rear tailgate is only capable of being moved to the open position when the grinding mechanism and the spreading mechanism are activated.  
         [0008]     The truck body may also include a first chute for directing material that is discharged from the truck body onto the grinding mechanism.  
         [0009]     The grinding mechanism includes a drive system operatively connected to a grinder configured to receive material to be ground. In one version the grinding mechanism includes a motor, a chain, and proximal and distal shafts with grinding teeth. The motor engages the chain and the movement of the chain causes the shafts and teeth to rotate. The rotation of the shafts and teeth causes material in the grinding mechanism to be ground.  
         [0010]     The truck body may include a second chute for directing the material from the grinding mechanism to the spreading mechanism.  
         [0011]     The spreading mechanism includes structure for dropping or broadcasting material onto a desired surface. In one version the spreading mechanism includes a motor, a drive shaft and a spinner. The motor engages the drive shaft and causes it to rotate. The drive shaft extends vertically from the center of the spinner and causes the spinner to rotate. The rotation of the spinner causes the material that is dropped onto the spreading mechanism to be distributed onto the desired surface.  
         [0012]     In one embodiment, the truck body includes a screen positioned atop the truck body for screening large material as it is loaded into the truck body. In one embodiment, the screen is positioned along the top of the truck body and is in two halves. Each half of the screen is movably connected to the truck body and is not restricted from upward movement. Each half of the screen engages with a lift mechanism, such as a hydraulic piston, for opening the screen. A center bar can be provided traversing the opening of the truck bed for supporting the screen and for anchoring the lift mechanisms. The screen itself can also be strengthened with supports. When the screen is lifted, the large material exceeding a predetermined size can be dumped off the sides of the truck body.  
         [0013]     In another embodiment, the screen has an outwardly curved shape for allowing the material that is too large to pass through the screen to fall to the sides of the truck body without having to elevate or pivot the screen. In this embodiment, the screen may also be strengthened with reinforcing arcuate ribs, a horizontal support and vertical supports to allow the screen to withstand a heavy load of material that is dumped thereon.  
         [0014]     The method of the present disclosure includes providing a truck body with a rear tailgate, a conveyor, a grinding mechanism and a spreading mechanism. To operate the grinder and spreader apparatus, the rear tailgate is opened to allow the unground material to be moved by the conveyor to the grinding mechanism. The grinding mechanism then grinds the material that exceeds the predetermined maximum allowable size. From the grinding mechanism, the material that is smaller than or equal to the predetermined maximum size is moved to the spreading mechanism. The spreading mechanism distributes the material from the grinding mechanism onto a surface. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     Embodiments of the presently disclosed grinder and spreader apparatus are described herein with reference to the drawings, wherein:  
         [0016]      FIG. 1  is an enlarged, partial side elevation view of a truck having a grinding mechanism located above a spreading mechanism in accordance with this disclosure;  
         [0017]      FIG. 2  is an enlarged side view of the rear end of the truck of  FIG. 1  showing the grinding mechanism and the spreading mechanism;  
         [0018]      FIG. 3  is a rear end view of the truck of  FIGS. 1-2  showing a rear tailgate in a closed position;  
         [0019]      FIG. 4  is a rear end view of the truck of  FIGS. 1-3  showing the rear tailgate in an open position;  
         [0020]      FIG. 5  is a partial side elevation view of the truck of  FIGS. 1-4  showing the grinding mechanism located above the spreading mechanism, showing the rear tailgate in a closed position and showing an optional screen in an open position located atop the truck body;  
         [0021]      FIG. 6  is a partial perspective view showing the front of the truck of  FIGS. 1-4  with an optional curved screen in place;  
         [0022]      FIG. 7  is a partial perspective view showing the front of the truck of  FIGS. 1-5  with an optional flat screen in place, illustrated in a closed position;  
         [0023]      FIG. 8  illustrates the optional flat screen of  FIG. 7  in an open position;  
         [0024]      FIG. 9  is a perspective view of the grinding mechanism illustrated with longitudinally off-set teeth;  
         [0025]      FIG. 10  is a perspective view of the grinding mechanism of  FIG. 9  illustrated with longitudinally in-line teeth;  
         [0026]      FIG. 11  is a top view of the grinding mechanism of  FIG. 10 ; and  
         [0027]      FIG. 12  is a top plan view of a spinner of the spreading mechanism. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0028]     Referring now in specific detail to the drawings in which like referenced numerals identify similar or identical elements throughout the several views. In the drawings and in the description which follows, the term “proximal” will refer to the portion of the grinder and spreader apparatus which is closest to the front of the truck, while the term “distal” will refer to the portion of the grinder and spreader apparatus which is farthest from the front of the truck.  
         [0029]     A truck  10  includes a truck body  14  mounted on a truck frame  18 . The truck  10  incorporates a grinding mechanism  200  positioned above a spreading mechanism  150  in accordance with one embodiment of the present disclosure is shown in  FIGS. 1-5 .  
         [0030]     The truck body  14  has a rear tailgate  22  which, in its closed position ( FIG. 3 ), prevents the material in the truck body  14  from unintentionally exiting the truck body  14 . In its open position ( FIG. 4 ), the rear tailgate  22  allows for the material in the truck body  14  to be discharged to the grinding mechanism  200 , as described below. In this embodiment, the act of opening the rear tailgate  22  is coordinated with the operation of the grinding mechanism  200  and the spreading mechanism  150 . In such an embodiment, material cannot be discharged from the truck body  14  unless the grinding mechanism  200  and the spreading mechanism  150  are activated, thereby preventing material from not being ground and from being unintentionally dropped onto a surface.  
         [0031]     A conveyor system  30  is integrated into a bottom structure  34  of the truck body  14  to provide a multiple purpose truck which can be used in a conveyor dispensing mode of operation. The conveyor system  30  is best seen in  FIG. 2 . Integrated conveyor systems are generally known to those skilled in the art and the embodiment shown includes a central, longitudinally extending conveyor  32  in the bottom structure  34  of the truck body  14 .  
         [0032]     A first chute  40  is mounted in part on the truck frame  18  below the rear end of the conveyor  32  and directs the material contents of the truck body  14  to grinding mechanism  200 .  
         [0033]     The grinding mechanism  200  is shown in  FIGS. 9-11 . When the material contained in the truck body  14  is directed onto the grinding mechanism  200  by conveyor  32 , portions of such material may pass through grinding mechanism  200  if they are of a small enough size. Clumps of material that are too big to simply pass through grinding mechanism  200  are ground until they are small enough to pass though the grinding mechanism  200 . Grinding mechanism  200  generally comprises housing  202 , distal shaft  210 , proximal shaft  220 , motor  240 , proximal gear  242 , motor gear  244 , chain  245 , distal shaft teeth  250 , proximal shaft teeth  252  and grinding teeth  260 . Motor  240 , which can be powered by any means (e.g., electrical, pneumatic, hydraulic, etc.), causes motor gear  244  to rotate. Chain  245  rests on and between teeth of gears  242  and  244 . Motor gear  244  causes chain  245  to move and thus to rotate proximal gear  242 . Proximal gear  242  is operatively connected to proximal shaft  220 . Rotation of proximal gear  242  causes proximal shaft  220  to rotate. Proximal shaft teeth  252  are operatively connected to proximal shaft  220  and rotate as proximal shaft  220  rotates. Distal shaft teeth  250  are in contact with proximal shaft teeth  252  and consequently rotate in the opposite direction. Distal shaft  210  is operatively connected to distal shaft teeth  250  and thus distal shaft  210  rotates in the same direction and at a proportionate speed as distal shaft teeth  250 . Both shafts  210  and  220  rotate in opposite directions and the grinding teeth  260  that are operatively attached to each shaft  210  and  220  consequently rotate at the same rate and direction as their respective shafts.  
         [0034]     The speed at which shafts  210  and  220  rotate can advantageously be in the range of about 50 to about 150 rpm, preferably about 75 to about 100 rpm, although any speed that provides acceptable grinding can be used. In this embodiment, the speed at which the conveyor  32  moves is independent of the speed at which the shafts  210  and  220  rotate, and is independent of the speed at which a spinner  167  rotates.  
         [0035]     The rotation of the grinding teeth  260  causes any large chunks of material conveyed to the grinding mechanism  200  to be ground until they are small enough to pass therethrough. The size and spacing of the grinding teeth  260  and their distance from the housing  202  determines the maximum size of the material that can pass through the grinding mechanism  200 . These sizes and distances can be altered depending on the type and characteristics of the material to be spread. In one embodiment, the grinding teeth  260  on both the proximal shaft  220  and the distal shaft  210  are positioned longitudinally in-line relative to their respective shafts (see  FIGS. 10 and 11 ). In another embodiment, the grinding teeth  260  of the proximal shaft  220  and/or the distal shaft  210  are positioned in a staggered, off-set fashion, i.e., not in-line, relative to their respective shafts (see  FIG. 9 ). In both the in-line and off-set embodiments, the grinding teeth  260  from the proximal shaft  220  and the grinding teeth  260  from the distal shaft  210  are longitudinally positioned such that they alternately engage or mesh with one another upon rotation of the shafts  210  and  220 . Typically, the material should be ground to a size less than one inch.  
         [0036]     A second chute  41 , mounted below the grinding mechanism  200 , directs the material that has passed through the grinding mechanism  200  to the spreading mechanism  150  (see  FIG. 2 ).  
         [0037]     The spreading mechanism  150  of the present disclosure can be stationary or of any other type. As seen in  FIG. 2 , a spreader  42  forms part of spreading mechanism  150  and mounts on the parallel channel beams  16  of the truck frame  18 . Rear end structure  158  comprises a transverse channel beam  166  and one or two intermediate, laterally spaced mounting brackets  168  attached to and extending down from beam  166 . The spreader  42  thereby depends via the bracket  168 , from two support legs  156 . The rear end structure  158  can be permanently welded to the rear ends of the two support legs  156  or optionally connected by pins or the like so as to be interchangeable with other structures (not shown). Optionally, another rear channel beam can be mounted rearwardly of cross beam  166  to serve as a rear truck bumper (not shown).  
         [0038]     The spreader  42  is mounted below support legs  156 , centrally therebetween and with the spinner  167  rotatable about an axis  164  normal to the generally horizontal plane of the beams  16  and support legs  156 . A hydraulic drive motor  165  is mounted on a transverse spinner support bracket  170  with its drive shaft  172  extending upwardly through an opening in the spinner support bracket  170 . The spinner  167  is mounted on and secured to the drive shaft  172  for rotation by the motor  165 . The hydraulic motor  165  and hydraulic lines  161  leading to and from the motor  165  are part of a hydraulic system (having a manually operated valve and hydraulic pump, not shown) used for selectively rotating the spinner  167  with the motor  165 . In one embodiment, the hydraulic lines  161  are mounted within the channel openings in the support legs  156  to protect the hydraulic lines  161  and keep them free and clear of the truck body  14 .  
         [0039]     The spinner  167  is positioned centrally between the sides  24  of the truck body  14  below the first and second chutes  40  and  41  and the rear end of the conveyor  32 . In  FIG. 3 , the chutes have been omitted for clarity. The spreader  42  is thereby positioned for receiving the material contents of the truck body  14  discharged off the conveyor  32  at the rear end of the truck body  14  and passing downwardly through the first chute  40 , through the grinding mechanism  200  and through the second chute  41 . When the conveyor system  30  is operated to discharge the material contents of the truck body  14  off the rear end of the conveyor  32 , the spinner  167  is rotated by its drive motor  165  to spread the discharged material onto the roadway. The spinner  167  includes a plurality of rudders  169  radially disposed from the drive shaft  172  (illustrated in  FIG. 12 ) for helping to distribute the material onto the roadway.  
         [0040]     Optionally, a screen  15  is placed above truck body  14  so that when material is loaded into the truck body  14  (e.g., using a bucket loader), pieces of material that are too large to pass through the screen will be caught by the screen  15 . Embodiments of the screen  15  are illustrated in  FIGS. 3-8 .  
         [0041]     In one embodiment, depicted in  FIGS. 7 and 8 , the screen  15  is divided into two parts. Each part is movably connected to the side of truck body  14  at one end  300  and is not restricted from upward movement at its other end  302 . A lift mechanism  304 , such as a hydraulic piston, is used to lift each half of screen  15 . One end of the lift mechanism  304  is operatively connected to the screen  15 . The other end of the lift mechanism  304  is operatively connected to a center bar  306  that traverses the length of the truck body  14  and also functions to support the screen  15  when in a closed position ( FIG. 7 ). In one embodiment, cross beams  308  are disposed on the top of the truck body  14 , traversing the width thereof, for providing additional support for the screen  15 . Screen supports  310  are disposed on the screen  15 , in one embodiment, for providing yet additional support.  
         [0042]     When the truck  10  is loaded with material, the material that is too large to pass through the screen  15  remains thereon. The lifting of the screens  15  causes the large material to fall off the sides of truck body  14 . It is also contemplated that the lift mechanisms  304  lift the screens  15  in a non-steady, or shaky motion, for sifting the material through the screens  15  as they open.  
         [0043]     In another embodiment, the screen  15  is curved so that when material is loaded onto the truck  10 , the large pieces of material roll off the sides of the truck  10 . In one embodiment, the screen  15  has reinforcing arcuate ribs  17 , vertical supports  19  and horizontal support  21  to provide adequate strength to withstand the removal of any large pieces that remain on screen  15  without damaging the screen  15 .  
         [0044]     Although the illustrative embodiments of the present disclosure have been described herein with reference to the accompanying drawings, it is to be understood that the disclosure is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the disclosure. For example, the truck body can be either a stationary or a moveable truck body. As another example, the conveyor can be a belt-type conveyor or a screw-type conveyor. As another example, the screen can be one piece and lifted by a single lift mechanism. As another example, a side of the screen can have a curved shape for further ensuring large pieces of material do not enter the truck body. As another example, the spreader can be stationary or moveable (e.g., retractable or pivotable). As another example, the motor for driving the spinner can be powered by means other than hydraulic, such as electrical, pneumatic, etc. As yet another example, the grinding mechanism can contain any reasonable number of shafts, including a single shaft. All such changes and modifications are intended to be included within the scope of the appended claims.