Abstract:
A portable material delivery apparatus for transporting and depositing a flowable material at a deposit site, including a vehicle and a hopper mounted on the vehicle for holding the material and having a lower opening for releasing the material. First and second circulating conveyors move the material released from the hopper to the deposit site. The first conveyor is fixed beneath the hopper. The second conveyor is vertically tiltable and laterally rotatable relative to the first conveyor. The apparatus includes a control station with an operator platform and controls for controlling the conveyors. The control station is mounted to and is movable with the second conveyor as it tilts and rotates. The control station is positioned such that a single operator standing on the operator platform can operate the controls while directly observing the material moving on the second conveyor and being ejected toward the deposit site.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/076,105, filed Nov. 6, 2014 and entitled Blast Hole Stemming Machine, the disclosure of which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to the field of material transport and delivery. More particularly, this invention relates to an apparatus to facilitate transport and precise delivery of a flowable material to a deposit site, particularly those deposit sites having restricted conditions. 
       BACKGROUND AND SUMMARY 
       [0003]    Explosive blasting in construction and mining operations requires drilling a large number of blast holes into the ground, typically in a grid pattern across the entire blast site, placing explosive charges into the holes and then detonating the charges. The explosion fragments solid rock by sending shock waves through the ground, which makes the process of removing the rock significantly easier. 
         [0004]    Before the explosives are detonated, the blast holes are covered with non-volatile matter, such as crushed gravel and water, in a process commonly referred to as stemming. Each of the blast holes is stemmed to prevent high velocity explosive blast gases from escaping through the top of the blast holes. Minimizing or preventing the escape of the blast gases is important for at least two reasons. First, creating the shock wave that fragments rock requires a buildup of pressurized gas. If the blast gases were permitted to escape out of the blast hole, the effectiveness of the blast would be greatly diminished. Second, stemming the blast holes makes the detonation much safer by minimizing the amount of material that is projected from the blast hole. 
         [0005]    Often times the stemming process is carried out using front end loaders, track hoes, skid loaders, etc. Other times, due to the blast site conditions, hand carrying buckets of stemming material to each blast hole and pouring the material into the hole is required. An advantage of this method is that the worker can inspect the material as it fills the hole. This is important because material that is too large or foreign materials may cause the blast to become less effective or even dangerous. Given the large number of blast holes that are present at each blast site, the stemming process has historically been very labor intensive and time consuming. 
         [0006]    Another method for stemming holes has been to fill a large dump truck. This process involves, for example, filling the truck with stemming material using a front loader, driving the truck to the blast site, pouring the stemming material into a blast hole using a conveyor system mounted to the truck, and then driving to the next blast hole and repeating the filling process. However, using this method does not provide an opportunity for the truck operator to inspect the stemming material as it fills the hole. Also, due to their large size, these types of large trucks are not well suited for sites have restricted or limited space. 
         [0007]    Accordingly, there is a need for an apparatus that enables stemming material to be quickly and conveniently poured into a blasting hole in locations having restricted or limited space and that allows a worker to directly inspect the material as it is poured. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Further advantages of the invention are apparent by reference to the detailed description when considered in conjunction with the figures, which are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: 
           [0009]      FIG. 1  is a side elevation view of a portable material delivery apparatus according to an embodiment of the present invention; 
           [0010]      FIG. 2  is a plan view of a portable material delivery apparatus according to an embodiment of the present invention, including a main conveyor rotating laterally from left to right relative to a feed conveyor; 
           [0011]      FIG. 3  is a rear elevation view of a hopper and vehicle for a material delivery apparatus according to an embodiment of the present invention; 
           [0012]      FIG. 4  is a perspective view of a hopper for a material delivery apparatus having a movable drop gate and door seal, door lifters for lifting the door, and a spreading baffle; 
           [0013]      FIG. 5  is a perspective view of the hopper shown in  FIG. 4  depicting flowable material being released from the hopper onto a feed conveyor belt; 
           [0014]      FIG. 6  is a side elevation view of a hopper, feed conveyor, and main conveyor according to an embodiment of the present invention; and 
           [0015]      FIG. 7  is a side elevation view of a main conveyor tilting upwards and downwards and depositing flowable material at a deposit site according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    The present disclosure provides embodiments of an agile material transport and delivery apparatus that is optionally self-loading and self-unloading and that provides a floating user platform that enables the user to visually inspect the material prior to being deposited and as it is deposited at a deposit site. These features make this apparatus well suited as a stemming machine used in the transport and delivery of flowable stemming material, such as a crushed rock and water slurry, to blasting holes. These features also make this apparatus well suited for other applications as well. For example, the apparatus may be used in the landscaping industry for the transport and delivery of gravel, peat moss, mulch, fertilizer and the like, including in residential locations having restricted or limited space. In the description that follows, the apparatus is described as a stemming machine in order to simplify the description but should not be understood to limit the scope of the invention. The term “flowable material” refers to materials that may be carried and deposited by the material transport and delivery apparatus disclosed herein, including gravel, sand, rock, dirt, mulch, fertilizer, and the like. 
         [0017]    Referring now to the drawings in which like reference characters designate like or corresponding characters throughout the several views, there is shown in  FIGS. 1-3  a portable material delivery apparatus  100  for transporting and selectively depositing a flowable material M at a deposit site D according to an embodiment of the present invention. The apparatus  100  generally includes a vehicle  102 , a hopper  104  mounted on the vehicle, first and second circulating conveyor belts  106 ,  108  mounted on the vehicle, and a control station  110  mounted to the second conveyor belt. In this particular embodiment, the vehicle  102  is driven by a gas-powered engine and the conveyors are driven by hydraulics. 
         [0018]    The vehicle  102  preferably includes a small chassis, about the size of a pickup truck, which makes the apparatus highly agile when compared to other stemming machines which are typically mounted onto large dump trucks. This enables the apparatus  100  to be maneuvered more easily and to travel into places that larger vehicles would not be able to travel. 
         [0019]    The hopper  104  is mounted onto the vehicle  102  and holds the flowable material M while it is being transported before being deposited. The hopper  104  is mounted vertically above the first conveyor  106 , also called the feed conveyor, so that flowable material M released from the hopper falls onto the first conveyor. As shown in  FIGS. 2-4 , the hopper  104  is formed by front and back walls and sidewalls that may be straight or angled, and a bottom. In this particular embodiment, the sidewalls are angled to facilitate the flowable material being released from the bottom of the hopper. The sidewalls form a bottom chute  112  having a number of openings  114  that are sized and positioned to release the flowable material M. In a preferred embodiment, the hopper is fixedly mounted to the vehicle at an angle Θ (shown in  FIG. 1 ) of about 10 to about 45 degrees such that the front end of the hopper is elevated with respect to the back end. The hopper is preferably angled in this manner to facilitate drainage and to also assist in moving the flowable material out of the bottom openings. Angling the hopper  104  also allows for it to be properly aligned over the first conveyor  106  and for the first conveyor to also be properly positioned over the second conveyor  108 , also called the main conveyor. Angling the hopper  104  achieves this proper positioning while also maintaining a relatively low center of gravity, which improves the handling and safety of the apparatus. Without the angling, in order to maintain the proper positioning of the conveyors  106 ,  108 , the hopper  104  would have to be placed at a much higher level and the center of gravity of the apparatus  100  would be much higher, leading to a more top-heavy and potentially dangerous machine. 
         [0020]    The hopper  104  may have either an open top or a closed top. The open top version of the hopper may be filled with flowable material M using traditional means, such as a front loader. Alternatively, either the open or closed version of the hopper  104  may be self-filling and be equipped with means for filling the hopper without the need for a front loader or the like. For example, in certain embodiments, the hopper  104  may be equipped with a vacuum system that is designed to suction flowable material M and to deposit that flowable material into the hopper, or vice versa. In the case of a closed top version of the hopper  104 , the entire hopper may be constructed as a sealable vacuum chamber and including suction means for providing a vacuum force and intake means for filling the hopper with flowable material M. For example, as shown in  FIG. 4 , this particular embodiment of the hopper  104  has a closed top and includes a sliding V-shaped drop gate  116  that is placed above the chute located at the bottom of the hopper. The drop gate  116  covers the openings  114  in the bottom of the hopper  104  and prevents the flow of flowable material out of the hopper. The drop gate  116  is configured to be raised and lowered, preferably on tracks located along inside walls of the hopper  104 , by lifters  118  such as hydraulic gate lift cylinders. Another function of the drop gate  116  is to provide a seal between the lower openings  114  and the upper section of the hopper  104  to enable a sufficient vacuum pressure to be created inside the hopper. Gaskets  120 , such as rubber seals, may be placed around the openings to improve the vacuum seal between the openings  114  and the drop gate  116 . 
         [0021]    A vacuum blower  122  connected to the hopper  104  creates the internal vacuum pressure and is sized to quickly suction flowable material M and to deposit it in the hopper  104 . A first vacuum hose  124  is mounted to an inlet  126  at an intake side of hopper  104 . The first hose  124  is used when suctioning flowable material M from a supply location for filling the hopper  104 . The hopper  104  may optionally include a dispersion baffle  128  located inside the hopper and mounted adjacent the inlet  126  in the flow path of the incoming flowable material M. In this particular case, the dispersion baffle  138  is somewhat V-shaped and it is used to spread or disperse the flowable material M as it is suctioned and deposited into the hopper  104 . The shape of the baffle causes the flow of flowable material to be split leftwards and rightwards as it enters the hopper  104 . Similarly, internal baffles  130  mounted on the left and right sides of the hopper  104  assist in guiding the flowable material M towards the lower openings  114  so that the material is ready for release when the drop gate  116  is lifted. A second vacuum hose  132  is mounted to an outlet  134  at an exhaust side of the hopper  104 . The opposite end of the second vacuum hose  132  is mounted to the vacuum blower  122 . A filter  136  located inside the hopper  104  and mounted at the outlet  134  filters particulate matter in the air. In use, the vacuum blower  122  may be used to suction flowable material M for filling the hopper  104 , for removing flowable material from a blast hole, etc., thereby eliminating the need for buckets or front loaders to fill the hopper. 
         [0022]    Once the hopper  104  has been filled with flowable material M, the material is transported by the vehicle  102  and is then deposited at the deposit D site by the circulating conveyors  106 ,  108 . With reference to  FIGS. 2, 5 and 6 , the first conveyor  106  is positioned below the hopper  104  so that flowable material M falls through the openings  114  and onto the conveyor belt. The first conveyor  106  includes an elongate first frame  138  having a first end and a second end. First primary rollers  140  are rotatably mounted at the first and second ends of the first frame. A first circulating conveyor belt  142  is positioned on the first frame over the primary rollers  140  and is configured to circulate around the first and second ends of the first frame when the primary rollers rotate. The first belt  142  includes a first receiving portion  144  located below the lower openings  114  of the hopper  104  for receiving the flowable material M released from the hopper. The first belt  142  also includes a first depositing end  146  from which the flowable material M drops as the first circulating belt circulates. The first conveyor  142  also includes a number of support roller pairs  148 . Each pair of support rollers  148  is arranged in a V-shaped formation and is positioned along a bottom surface of the first circulating conveyor belt  142  and supports the belt. The outer edges or sides of the belt  142  are raised by the support rollers and form a trough  150  along a central portion of the belt between the raised sides. The raised sides and trough  150  bias the flowable material M released from the hopper  104  into a unified stream as the flowable material moves from the first receiving portion  144  of the first conveyor to the first depositing end  146 . Providing this unified stream assists in having a more uniform and consistent flow rate of material and helps to ensure that material is not lost over the sides of the circulating belt. 
         [0023]    With reference to  FIGS. 6 and 7 , once flowable material M reaches the first depositing end  146 , it falls from the first conveyor  106  onto the second conveyor  108 . The structure of the second conveyor  108  is substantially similar to that of the first conveyor  106 . The second conveyor  108  includes an elongate second frame  152  having a first end and a second end. Second primary rollers  154  are rotatably mounted at the first and second ends of the second frame  152 . A second circulating conveyor belt  156  is configured to circulate around the first and second ends of the second  152  frame when the second primary rollers  154  rotate. The second conveyor belt  156  includes a second receiving portion  158  located below the first depositing end  146  of the first circulating conveyor belt  142  for receiving the flowable material M dropped from the first depositing end. The second belt  156  also includes a second depositing end  160  from which the flowable material M is ejected toward the deposit site D as the second circulating conveyor belt  156  circulates. Support roller pairs  162  are arranged in a V-shaped formation and are positioned along a bottom surface of the second circulating conveyor belt  156  and form a trough along a central portion of a portion of the belt between raised sides of the belt. 
         [0024]    As discussed above, the first conveyor  106  is fixedly mounted along the bottom of the hopper  104  at an angle. The second conveyor  108 , however, is vertically tiltable and laterally rotatable relative to the first circulating conveyor belt to allow the second depositing end  160  to be correctly placed in close proximity to the deposit site D. Importantly, the second receiving portion  158  remains vertically below the first depositing end  146  at all times regardless of the vertical or lateral position of the second depositing end  160 . This ensures that flowable material M falls onto the second conveyor  108  from the first conveyor  106 . As shown in  FIG. 2 , the second conveyor  108  can rotate left or right up to 180°. As shown in  FIG. 7 , the second conveyor  108  can tilt upwards and downwards up to about 45°. Both conveyor belts  142 ,  156  may be speed adjustable, which enables the flow rate of flowable material to be increased or decreased, preferably the speed of each belt is the substantially the same and may be simultaneously adjusted. Additionally, with respect to the second conveyor  108 , increasing and decreasing the speed causes the flowable material to be ejected varying distances from the second depositing end. The titling, rotating and speed adjustments described above enable the apparatus  100  to launch the flowable material M at various trajectories into several deposit sites D without the vehicle being moved. 
         [0025]    The vehicle  102  may be driven and the conveyors  106 ,  108  operated by a single operator located at a floating control station  110 . The control station  110  includes an operator platform  164  that is mounted to the second frame  152  and is located adjacent to the second depositing end  160  of the second circulating conveyor belt  108 . The control station  110  is “floating” because when an operator stands on the platform  164 , he moves with the second depositing end  160  as the second circulating conveyor belt  108  vertically tilts and laterally rotates. The control station  110  also includes controls  166  that are near the platform that enable a single operator to operate the vehicle  102  and the conveyors  106 ,  108  while, at the same time, have a nearly ground-level direct line-of-sight view of the flowable material M moving along the second conveyor  108  and being ejected from the second depositing end  160  toward the deposit site D. 
         [0026]    The foregoing description of preferred embodiments for this disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the disclosure and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the disclosure as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.