Abstract:
A tub grinder is used for grinding industrial wastes, including large stumps, lumber chunks and the like. A cover member is pivoted alongside the tub, and is made in two sections. An upright frame section is pivoted near a plane along the bottom of the tub, and extends upwardly to a level at or adjacent to the top of the tub. A cover section is pivotally mounted to the upright frame and can be adjusted about a generally horizontal axis from a generally horizontal position to an upwardly extending position. The upright frame can be tilted outwardly so that the cover section is out of registry with the tub to permit the tub to be loaded.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority of U.S. Provisional Application Ser. No. 60/253,577, filed Nov. 28, 2000, entitled COVER FOR TUB GRINDER. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a tub grinder that is used for grinding industrial waste, such as stumps, brush, pallets, large timbers, demolition debris, trees and limbs, lumber piles and the like into particulate material that can be easily disposed of, used as a mulch ground cover or other uses, and which has a openable cover that will intercept debris that may be ejected from the open top of the tub during use. The cover, as shown, is mounted in a unique matter so that complete covering of the tub opening can be obtained, and the cover can easily be opened for filling the tub.  
           [0003]    In the prior art, various industrial waste tub grinders have been utilized. U.S. Pat. No. 5,419,502 shows such a device. Tub grinders have been used for grinding hay and straw for years.  
           [0004]    The assignee of the present application developed and sold a cover or lid for a tub grinder that hinged in a different manner from the present mounting by pivotally mounting the cover along a top edge of the tub. It was used as a containment device and could be adjusted in position with a winch and cable.  
           [0005]    Tub grinders use a rotating grinding cylinder that has hammers or flails that are positioned to extend through an opening in the floor of the tub and engage material that is in the tub. The ground material is dropped down through a screen, onto a conveyor, and then conveyed where desired for disposal.  
           [0006]    When the tub is partially full, or is being emptied, the material in the tub is at times not sufficient to prevent chunks of material engaged by the grinding cylinder or flails to be thrown through the material outwardly through an open top of the tub. It is during these times when a cover member is desired to intercept the trajectory of chunks or objects, and prevent the chunks from being thrown into the surrounding area.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention relates to a tub grinder cover that has an upright frame mounted for pivotal movement about a horizontal axis that is adjacent one side of the tub. The upright frame will tilt sideways from a generally vertical position away from the tub. In a preferred form a cover member is pivoted about a second horizontal axis at the upper end of the upright frame. Hydraulic cylinders are used for controlling the pivoting of the upright frame and the cover member about their respective mounting axis.  
           [0008]    The cover of the present invention thus easily moves so that the cover can be moved to completely overlie the tub when desired, or moved to a position where the top of the tub is completely open for filling the tub. Additionally, various intermediate positions are possible. Changing the cover position will permit an operator to accommodate the conditions being encountered.  
           [0009]    During transport the cover is moved to overlie the tub, and to lie over a folding elevator conveyor that is used for conveying the ground material. The elevator is folded over the top of the tub for transport or storage, and the cover overlies the folded elevator so the transport height required for the tub unit is kept low.  
           [0010]    The tub grinders used for industrial waste are large and heavy, and are generally mounted onto semi-trailers and pulled with a truck/tractor between locations.  
           [0011]    The present cover is formed with a framework that carries screen panels that can easily be replaced if they become damaged. The screens will permit dust to be discharged without substantial hindrance and also will filter out pieces that are carried into the air. The screen also reduces the tendency of the cover to become a “sail” in windy conditions. The screen reduces the wind load on the cover supports. The wind can pass through easily. The angle of incident of thrown objects causes even small objects to be deflected. If any small objects do pass through the screen, the energy of the small objects is reduced. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a schematic partial perspective view of a tub grinder having a cover member made according to the present invention installed thereon in a storage position;  
         [0013]    [0013]FIG. 2 is a fragmentary perspective view of the tub grinder of the present invention, showing the cover member in a closed or covering position;  
         [0014]    [0014]FIG. 3 is a part schematic side view showing a folding conveyor and taken on line  3 - 3  in FIG. 4;  
         [0015]    [0015]FIG. 4 is a fragmentary front elevational view showing the cover in a first position where the cover section is raised, with an upright support frame in a vertical position, and with a closed position of the cover shown in dotted lines; and  
         [0016]    [0016]FIG. 5 is a front view showing the cover in a full open position with the support frame inclined outwardly and the cover member in its full open position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    Referring to FIG. 1, a tub grinder and cover assembly indicated generally at  10  utilizes a conventional tub grinder  12 , which has a rotating tub  14  mounted onto a frame  16 , and rotatable about an upright axis. The frame  16  is a semi-trailer frame, as shown, and is supported on wheels  18  and pulled by a truck-tractor (not shown). The tub grinder  10  is powered through a large power unit, such as an internal combustion engine  20 , that is mounted on the frame  16  and is used for driving the various components.  
         [0018]    A tub cover assembly  22  is made so that it will overlie the open top of the tub  14  or can be moved to clear the tub. The cover assembly  22  is shown in its storage position in FIG. 1, with an outer end section  24  of a folding conveyor  26  lying on top of the upper flange edge  28  of the tub and underneath an outer cover section  30 .  
         [0019]    The tub  14  is rotated by a tub drive illustrated schematically in FIGS. 4 and 5. The tub  14 , as shown in FIG. 5, rotates over a bottom wall  32  that is stationary. The tub  14  rotates around an upright axis over this bottom wall. The tub  14  is mounted on suitable roller supports  34  in a conventional manner relative to the frame  16 , and then is driven with a rotary drive  36  driven from the power unit  20 . The drive can be any conventional, presently used tub drive.  
         [0020]    A grinding cylinder or rotor similar to a hammer mill is indicated at  38 , and is mounted on a central shaft  40  for rotation in direction as indicated by the arrow  42 . The grinding cylinder  38  has hammers or flails  44  that will engage material in the tub, shown schematically at  46  in FIG. 5, as it rotates. The shaft  40  is driven from the power unit  20  in a conventional manner.  
         [0021]    As the material in the tub is ground, it will pass through a suitable screen  48  shown schematically, and drop down onto a horizontal conveyor  50  shown in FIGS. 4 and 5 schematically. The material is then carried rearwardly, to a lift conveyor that again is shown schematically in FIG. 3 and is indicated at  26 . The conveyor  26  is made in sections, includes the base section  58 , as well as the outer end section  24 . The base conveyor section  58  is pivotally mounted to the main frame  16  at a pivot  60  for example, and the outer conveyor section  24  is pivotally mounted to the outer end of the base conveyor section  58  at a pivot  62 . The base conveyor section  58  is moved about its pivot  60  with a double acting hydraulic cylinder  64 , that is connected to the frame  16  and has its rod end connected at  66  to the base conveyor section. The base conveyor section can be pivoted from a generally upwardly inclined position as shown in FIG. 3, to a substantially vertical position at the rear of the tub  14 . The pivoting of the outer end section  24  of the conveyor  26  about pivot  62  is controlled with a double acting hydraulic cylinder  68 , so it can be pivoted to a position generally inverted and horizontal when the base conveyor section is vertical, and an intermediate position as shown in dotted lines in FIG. 3. The conveyor is folded for travel and storage. The conveyor is powered in a suitable manner for example by a hydraulic motor  70 .  
         [0022]    The cover assembly  22 , which includes the outer cover section  30 , is mounted to the main frame  16 , as can perhaps best be seen in FIG. 2. The frame  16  has laterally extending sections that support arms  72  at the front and rear of the tub grinder. The frame arms  72  have ear members  74  that have pivot pins  76  supporting upright members  78  of an upright cover frame assembly  80 .  
         [0023]    The upright cover frame assembly  80  has suitable cross members  82  thereon, so that the upright cover frame is rigid and will be a stable support for the outer-cover section  30 . The cover section  30  has side frame members  84 , and intermediate frame members  86  that support suitable screen panels  88 . The frame for the outer cover section  30  also has a base member  90  that is attached to the end frame members  84  and the intermediate members  86 , and also has an outer end cross member  92  as can be seen in FIG. 3 for example to hold the frame section together. The screen panels  88  can be attached in a suitable manner so that they can be replaced if damaged. The outer cover section  30  is pivotally mounted to the upright frame members  78  on suitable pivot pins  92  that form a horizontal pivot axis. The outer cover section  30  can be tilted relative to the upright frame  80  through the use of double acting hydraulic actuators or cylinders  94  that are mounted to the upright members  78  at pins  96 . The rod ends of cylinders  94  are connected to the outer cover section  30  with suitable brackets  98 . The hydraulic actuators  94  are operated through controls indicated at 100, and these controls include valves that control hydraulic fluid under pressure from a pump  102  to the cylinders.  
         [0024]    The tilting of the upright cover frame assembly  80  is controlled by hydraulic actuators or cylinders  104 , that are mounted as at  106  to inner ends of the arms  72 . The rod ends of cylinder  104  are connected to brackets  108  on the upright frame members  78 .  
         [0025]    The open top of the tub is shown at  110  in FIG. 2. The open top is where material to be ground is introduced into the tub  14  for grinding with the grinding cylinder  38 . The open top  110  has to be accessible for loading the tub with material to be ground.  
         [0026]    The positions of the cover assembly in addition to the position shown in FIGS. 1 and 2 where the outer cover section  30  is overlying substantially the entire opening  110  of the tub  14 , include the solid line position shown in FIG. 4 where the upright cover frame assembly  80  is substantially vertical, with the cylinders or actuators  104  retracted, and the outer cover section  30  is in its fully opened position with the actuators  94  retracted. The dotted line position shown in FIG. 4 for the outer cover section  30  is with the actuators  94  extended, and the outer end section  24  of the conveyor  26  is also illustrated in FIG. 4 in dotted lines.  
         [0027]    With the upright frame  80  generally vertical, and the outer cover section  30  raised, as shown in FIG. 4, it can be seen that material being thrown out of the tub toward the frame side (which is the direction material will travel from rotation of the grinding cylinder) will be intercepted by the screen portions of the outer cover section  30  and will drop back into the tub. For example an object indicated at  114  is shown in dotted lines. The outer cover section  30  extends upwardly a substantial distance, as shown, to intercept objects deflected upwardly.  
         [0028]    In the position shown in FIG. 4, with the cover section  30  fully open, that is with the cylinders  94  retracted, and the upright cover frame  80  vertical, the cover assembly is stable. The opening to the left side indicated by the bracket  116  is of substantial size so that the tub can be loaded from that side of the tub grinder, without further opening. The frame  80  can be tilted outwardly as shown in FIG. 5 for permitting long material that sticks out the sides of the tub to pass by. The frame normally is pivoted outwardly and would be put in the vertical position when the tub is being emptied and the tub coverage is to be maximized. In the position shown in FIG. 5, the outer cover section  30  extends upwardly sufficient so that items being thrown out of the tub are going to be intercepted, because of the high extension, and wide coverage area of the cover section  30 . The tub cover is mounted on the tub frame and moves with the tub when the tub is raised for servicing or maintenance.  
         [0029]    It should be noted that the outer cover section  30  is made into three parts,  30 A, which is the section that is adjacent the upright frame  80 ,  30 B which is a center section, and  30 C which is a section that inclines downwardly from the section  30 B. The unit thus forms a type of “dome” that provides space for the outer conveyor section  24  and at the same times serves to provide deflection of debris in its working positions. The screen panels used in the cover section are bolted in place so they can be changed if damages, or if a different material is desired. Solid material cover panels can be used as well.  
         [0030]    Again, the amount of material in the tub can suppress or dampen the likelihood of an object to be thrown out of the tub and will stop or dampen its potential flight. The cover intercepts objects in its working positions, and can completely cover the tub opening so that there is no ejection of material. The position of the cover is easily controlled by the operator to suit existing conditions.  
         [0031]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.