Abstract:
An incline conveyor that includes driven rollers at both the input (tail) end and the output (head) end of the conveyor that are powered by a single power source. Power is transmitted along the length of the conveyor with a driveline that distributes power to both the input and output drive rollers. The position of the drive rollers is adjustable to tension and track the conveyor belt. The position of the gearbox is also adjustable to maintain tension on the drive belt. The resulting conveyor drive mechanism allows cleated belt conveyors to be longer and transfer at higher capacities.

Description:
FIELD 
       [0001]    This disclosure generally relates to a device for driving an uneven endless conveyor belt using powered drums at both the head and tail ends. 
       BACKGROUND 
       [0002]    The drive mechanism for conventional incline conveyors generally involve drive pulleys and idler rollers in various configurations. Incline conveyors are commonly arranged such that the belt passes over two cylindrical rollers, one at the input (tail) end and the other at the output (head) end of the conveyor. Friction between the contact surface area of one or more powered drive rollers and the conveyor belt causes the endless belt to be driven. 
         [0003]    A single-end drive pulley is commonly used to drive incline conveyors. Typically, the input roller is an idler roller; and the output roller is driven by a motor, and referred as the drive roller. Alternatively, the input roller could be driven and the output roller could be an idler. An example of an end drive conveyor is shown in U.S. Pat. No. 6,675,958 “Tube Conveyor” to Kaeb et al, the disclosure of which is incorporated by reference, which describes an endless belt incline conveyor driven from the input end or the output end. 
         [0004]    Alternatively, an incline conveyor can have idler rollers at both the input and output ends and be driven by an S-drive roller mechanism located between the ends. An example of a center S-drive conveyor is shown in U.S. Pat. No. 5,452,791 “Dual Drive for Belt Conveyor” to Morency et al, which describes an endless belt conveyor driven by center positioned tandem drive rollers. The two driving rollers engage the belt in an S-shaped drive roller configuration. Other similar configurations utilize a single driven roller and a snub roller that properly positions the belt around the drive roller. 
         [0005]    Proper conveyor belt tensioning is necessary to transfer power from the drive roller to the conveyor belt. Semi-elastic conveyor belts are generally installed around the end rollers, cut to length, and the belt ends are spliced together to form an endless conveyor belt. One or more end idler rollers are adjusted to stretch the semi-elastic conveyor belt around the end rollers. Generally, only the idler roller is adjustable since the drive roller is attached to the power source. For example, when the drive roller is moved, the power source must also be moved in order to maintain proper alignment of the power source components such as v-belts, gearboxes, and motors. Alternatively, snub rollers and S-shape roller configurations are used to apply tension to the conveyor belt. 
         [0006]    However, certain types of substantially uneven conveyor belts, such as the cleated belt described in U.S. Pat. No. 6,170,646 to Kaeb et al, “Cleated Belt Adaptable to Curvilinear Shapes”, the disclosure of which is incorporated by reference, interfere with rollers that contact the carrying surface of the cleated belt. As such, uneven conveyor belts cannot utilize snub rollers or drive rollers in an S-shape configuration for driving the belt or for tensioning. 
         [0007]    As a result, incline conveyors with substantially uneven belts are generally powered by a single drive roller in the head or tail of the conveyor. These conveyors have limited drive roller surface area, which limits the amount of driving energy that can be transferred to the conveyor belt through friction between the roller and the belt. Therefore the length and capacity of the conveyor is limited. One solution is to increase the diameter of the drive roller, thus increasing the contact surface area. However, the use of larger diameter drive rollers requires the use of many other enlarged conveyor components, which leads to increases in the size, weight, and cost of the conveyor. 
         [0008]    Longer conveyors also require greater conveyor belt uptake tensioning distances. Tensioning an uneven conveyor belt, such as a cleated belt, is generally accomplished by adjusting the position of the end idler roller relative to the end drive roller. The distance the end roller must be adjusted to maintain tension increases with conveyor length. Tensioning bolts are utilized on either side of the end idler roller to stretch the semi-elastic conveyor belt to the predetermined degree of tension. 
         [0009]    Therefore it is apparent that there are numerous challenges in to using existing solutions to drive and tension a long, high capacity conveyor with a substantially uneven conveyor belt surface. Another limitation is the inability to properly tension the conveyor belt using adjustable end rollers when the end roller is driven, when the end roller is a driven roller that needs to maintain proper tension with a gear box through a drive belt. Existing solutions to drive and tension long conveyor belts rely on multiple independent power sources to drive the input and the output drive rollers. 
       SUMMARY 
       [0010]    It is therefore an object of the present invention to provide a conveyor that overcomes some or all of the problems associate with existing conveyor systems. For example, some advantages of the present invention include an apparatus which provides:
       a. increased drive capacity for conveyors utilizing substantially uneven conveyor belt carrying surfaces, such as cleated belts;   b. a conveyor in which a single power source transmits power to both the head and the tail drive rollers;   c. a conveyor in which the two disparate drive rollers maintain the same roller surface speed;   d. a conveyor in which the gearbox is adjustably positioned in order to maintain tension on the drive belt that connects the gearbox with the adjustably positioned drive roller;   e. a conveyor in which the conveyor belt tension is adjustably maintained with adjustable rollers at both the input and output ends of the conveyor.       
 
         [0016]    Accordingly, one aspect of the invention includes a conveyor with drive rollers at the input and output ends that are driven by a common power source. The power source can be, but is not limited to, power takeoff (PTO), electric, hydraulic, or a gas engine. The power source is connected to a driveline that powers gearboxes at the input and output end of the conveyor. The gearboxes transfer power to the respective drive roller through a belt connection. The gearbox, pulleys, and drive roller are configured such that the surface speed of the pair of drive rollers is maintained at the same rate. 
         [0017]    In another aspect of the invention, the increased drive capacity can be utilized with an incline conveyor with a substantially uneven belt to produce a high capacity conveyor that operates at greater lengths than existing cleated belt incline conveyors. The substantially uneven belt, such as a cleated belt conveyor, would otherwise interfere with the use of an S-drive configuration or a snub roller. The conveyor can be a tube conveyor. Incline tube conveyor transport lengths utilizing this technology can exceed 80 or 115 feet. 
         [0018]    In another aspect of the invention, the conveyor maintains proper tension on the conveyor belt by adjustably positioning both rollers at the input and output ends of the conveyor. Given the elastic nature of conveyor belts commonly used, the conveyor belt is installed and then placed under tension in order to provide sufficient traction between the conveyor belt and the drive wheels. Longer conveyor lengths require a greater amount of tensioning. Tensioning bolts are connected to the frame of the conveyor and to the ball bearing mount on the end roller. The cleated conveyor belt is initially tensioned to a determined level at one end. In a preferred embodiment, the output end is first tensioned. As the belt stretches, additional tensioning is required to maintain proper conveyor belt tension. Maintenance tensioning of the conveyor belt is applied at the opposite end of the initial tensioning. 
         [0019]    In another aspect of the invention, the gearbox is adjustably positioned in order to maintain proper drive belt tension between the gearbox and the adjustable drive roller. The gearbox is attached to an adjustment plate and a tensioning bolt to properly position the gearbox once the cleated belt conveyor has been properly tensioned. 
         [0020]    In another aspect of the invention, a telescoping driveline is utilized to connect the adjustable gearbox with the fixed driveline. The driveline connects the input gearbox and output gearbox with the power source. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0021]    Aspects are illustrated by way of example, and not by way of limitation, in the accompanying drawings, wherein: 
           [0022]      FIG. 1  is a side perspective view of the full length of the conveyor showing the two drive ends. 
           [0023]      FIG. 2  is a top, side perspective view of the input (tail) end of the conveyor showing the input drive mechanism. 
           [0024]      FIG. 3  is an exploded view of the input end of the conveyor, showing the assembly of the input drive mechanism. 
           [0025]      FIG. 4  is a top, side perspective view of an electric motor power source that is connected to the drive line. 
           [0026]      FIG. 5  is a top, side perspective view of the output (head) end of the conveyor showing the output drive mechanism. 
           [0027]      FIG. 6  is an exploded view of the output end of the conveyor, showing the assembly of the output drive mechanism. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Referring now to the invention in more detail, in  FIG. 1  there is shown a conveyor  1  with a conveyor frame  3 , an input end  5 , and an output end  10 . The input end  5  has an input drive roller  15  and an input gearbox  25 . The output end  10  has an output drive roller  20  and an output gearbox  30 . A fixed driveline  35  and a telescoping driveline  40  extend parallel to the conveyor frame  3 . 
         [0029]    In  FIG. 2  there is shown a detail view of the input end  5  of the device. The input gearbox  25  is slidably mounted to the conveyor frame  3 . The input gearbox  25  is operably connected to the telescoping driveline  40 . The telescoping driveline  40  extends and retracts parallel to the length of the conveyor to compensate for the variable position of the input gearbox  25 . 
         [0030]    An input drive pulley  109  operably receives the input gearbox  25 . The input drive pulley  109  is operably connected to the input drive roller pulley  135  with a belt drive  110 . The input drive roller pulley  135  operably receives the input drive roller  15 . The input drive roller  15  is slidably mounted within a drive roller slot  125  at the input end  5  of the conveyor frame  3 . A tensioning bolt  105  is an externally threaded bolt or stud that is threadably received within the tensioning bracket  115 . Threadably extending or retracting the tensioning bolt  105  causes the input drive roller  15  to slide within the drive roller slot  125 . 
         [0031]    In  FIG. 3 , there is shown the gearbox  25 . The gearbox  25  is slidably mounted to the top surface  111  of a base  112 . The base  112  has one or more slots  114  disposed parallel to the length of the conveyor. The gearbox is slidably mounted to the base with two or more gearbox mounting bolts  122 , such as four carriage bolts as depicted, that are received by the gearbox and pass through the slots  114 . The gearbox-tensioner  113  has a first tensioner end  116  that is configured to threadably receive one or more of the gearbox mounting bolts. The gearbox-tensioner  113  has a second tensioner end  117  that an externally threaded bolt or stud. The base  112  has a front surface  118 . The front surface  118  is configured with an opening  119  to receive the second tensioner end  117  of the gearbox tensioner  113 . The second tensioner end  117  passes through the opening  119  and is threadably received by a nut  121 . The gear box  25  is adjusted by threadably rotating the nut  121  such that the gearbox-tensioner  113  moves inwardly or outwardly with respect to the opening  119 . Movement of the gearbox-tensioner  113  causes the gearbox  25  to slide forward or backward along the slots  114  of the base  112 . 
         [0032]    The input drive roller  15  is operably received by an input ball bearing unit  130  on either end. The input drive roller  15  is received by a pair of drive roller end plates  140  on either end. A pair of drive roller slots  125  is disposed within the lateral sides of the input end  5  of the conveyor. Each drive roller slot  125  is configured to slidably receive the respective drive roller end plates  140 . An input drive roller pulley  135  operably receives the input drive roller  15  such that the rotating the input drive roller pulley  135  causes the input drive roller  15  to rotate. 
         [0033]    The tensioning bolt  105  is laterally disposed against the input ball bearing unit  130 . The tension of the conveyor belt  180  is adjusted by threadably rotating the tensioning bolt  105  inwardly or outwardly with respect to the tensioning bracket  115 . The tensioning bolt  105  presses against the input ball bearing mount  130  with varying pressure. The device utilizes a second parallel tensioning bolt to effectuate even pressure on both ends of the input drive roller  15  so that the tension and tracking of the conveyor belt is maintained. 
         [0034]    The configuration of the input gearbox  25  can either be a through shaft gearbox or a right angle gearbox depending on whether the power source is electric, power takeoff (PTO), hydraulic, or a gas engine. A PTO shaft  145  connected to a right angle gearbox. The PTO is operably connected to the input gearbox  25  and the input drive pulley  109 . Power is transferred through the telescoping driveline  40 , to the fixed driveline  35 , and to the output gearbox  205 . 
         [0035]    In  FIG. 4 , there is shown an electric motor that provides power from between the two drive rollers. There is shown an electric motor  150 . The electric motor is operably connected to the fixed driveline  35 . Power is transferred through the fixed driveline  35  to the output gearbox  205  and through the telescoping driveline  40  to the input gearbox  25 . 
         [0036]    In  FIG. 5 , there is shown the fixed driveline  35  operably connected to the output gearbox  205 . The output gearbox  205  is securely mounted to the conveyor frame  3  with one or more bolts or by welding. An output drive pulley  200  operably receives the output gearbox  205 . The output drive pulley  200  is operably connected to the output drive roller pulley  215  with a belt drive  210 . The output drive roller pulley  215  operably receives the output drive roller  20 . The output drive roller  20  is slidably mounted within an output drive roller slot  235  at the output end  10  of the conveyor  1 . An output-tensioning bolt  240  is an externally threaded bolt or stud that is threadably received within the output-tensioning bracket  245 . Threadably extending or retracting the output-tensioning bolt  240  causes the output drive roller  20  to slide forward and or backward within the output drive roller slot  235 . The output gearbox  205  is mounted at a pre-determined location so as to place the appropriate amount of tension on the output belt drive  210  when the output drive roller  20  is properly positioned by the output-tensioning bolt  240 . 
         [0037]    In  FIG. 6 , there is shown the output drive roller  20 . The output drive roller  20  is operably received by a plurality of output ball bearing units  220  on either end of the output drive roller  215 . A pair of output drive roller slots  235  is disposed within the lateral sides of the output end  10  of the conveyor. Each drive roller slot  235  is configured to slidably receive the respective output ball bearing unit  220 . An output drive roller pulley  215  operably receives the output drive roller  20  such that the rotating the output drive roller pulley  215  causes the output drive roller  20  to rotate. 
         [0038]    The output-tensioning bolt  240  is laterally disposed against the output ball bearing unit  220 . The tension of the conveyor belt  180  is adjusted by threadably rotating the output-tensioning bolt  240  inwardly or outwardly with respect to the output-tensioning bracket  245 . The output-tensioning bolt  240  presses against the output ball bearing mount  220  with varying pressure. The device utilizes a second parallel output-tensioning bolt to effectuate even pressure on both ends of the output drive roller  20  so that the tension and tracking of the conveyor belt is maintained.