Patent Publication Number: US-2011062743-A1

Title: Roll-out cover system for open container vehicles

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 10/556,154 filed Jan. 31, 2008, which is a national stage application of PCT Patent Application No. PCT/US2004/012903 filed Apr. 24, 2004, which claims priority to U.S. Provisional Patent Application Nos. 60/466,001 filed on Apr. 28, 2003 and 60/466,004 filed on Apr. 28, 2003 entitled. The disclosure of each of the above-identified applications is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to open top container vehicles in general, and in particular to apparatus for operating a roll-out cover for an open top container vehicle, such as a dump truck. 
     2. Background Information 
     It is known for trucks (e.g., dump trucks, container trucks, etc.) to use open top containers for transporting earth, sand, stone, waste, debris or similar materials. Open top containers are filled through the open top, and emptied by pivotally raising the container at an angle. A rear wall of the container typically swings open (or can be detached) as or before the container is raised, and the material exits through the opening. However, material is loaded into the container can be easily agitated—e.g., from bumpy roads or external winds—and is susceptible to being displaced from the container through the open top. Accordingly, the open top of the container is often covered during transport so as to prevent waste and debris from being ejected from the container. 
     As known in the art, a flexible cover extending transversely across the container width, and having sufficient length to cover at least the entire length of the container is provided on the container. Because loading of material is usually accomplished through the open top of the container, the flexible cover usually has a storage location where the cover is positioned out of the way during loading, and often unloading, of material from the container. The flexible cover is typically rolled out from the front of the container to the rear of the container, extending over the open top of the container. 
     Some prior art cover systems include a pair of pivot arms, a cross bar, and a take-up roller. One of the pivot arms is positioned on each side of the container. The cross bar extends between and is connected to the pivot arms. The pivot arms and attached crossbar are pivotable from a first position adjacent the front of the container to a second position adjacent the rear of the container. In some embodiments, the take-up roller is fixed to the front of the container (e.g., a dump body) or to the truck adjacent the front of the container. One end of the cover is attached to the take-up roller and the other end is attached to the crossbar. Pivoting the mins and crossbar from the front of the container to the rear of the container causes the cover to be unrolled from the take-up roller and the container covered. When the aims and crossbar are pivoted back toward the front of the container, the cover is rolled back onto the take-up roller. In other embodiments, the take-up roller is attached to the crossbar. One end of the cover is attached to the take-up roller and the other end is attached to the front of the container or to the truck adjacent the front of the container. Pivoting the arms and crossbar from the front of the container to the rear of the container causes the cover to be unrolled from the take-up roller and the container covered. When the arms and crossbar are pivoted back toward the front of the container, the cover is rolled back onto the take-up roller. 
     The pivot arms are commonly driven between covered and uncovered positions with an operating shaft assembly mounted on the frame of the truck or the container. For example, the operating shaft assembly may include a shaft running between the pivoting arms at the base of the container. The shaft communicates with each arm at its respective pivot point, and acts to pivot the arms upon rotation of the shaft. 
     While some roll-out cover systems make use of complex automated actuators and drive shafts specifically designed into the truck designs, several roll out cover systems rely on the operator to manually effect operation of the cover system between the covered and uncovered positions. That is, the operating shaft assembly is provided with an operating drive shaft that can be hand cranked to move the cover between the covered position and the uncovered position. The operating drive shaft is typically connected to a gearbox and chain drive. The gearbox provides some mechanical advantage to effort required to crank the mechanism. Covering and uncovering an open-top container still takes a substantial amount of time, however. If the operating drive shaft is located above the cab, the operator must also position himself on the cab, usually in an awkward position, to operate the hand crank. What is needed is an apparatus for covering and uncovering an open top container in a time efficient manner, with reduced operator effort and intervention, and with overall easier operation. Additionally, there is a need to retrofit existing truck containers adapted with roll-out covers using manual operation systems and components with automatic operation systems, where such retrofit is conducted with minimal reconstruction or replacement of the components of the existing operation systems. 
     DISCLOSURE OF THE INVENTION 
     According to the present invention, a roll-out cover system for a container having an open top is provided that includes a cover, a pair of pivot arms, a gearbox, a motor, a drive mechanism, and a controller. The cover has a leading end and a trailing end. The pivot arms are positioned on respective sidewalls of the container. Each pivot arm has a free end connected to the leading end of the cover, and a pivot end. The pivot arms are pivotable between a first position wherein the cover is retracted from the open top, and a second position wherein the cover is extended substantially over the open top. The gearbox has an input shaft and an output shaft. The motor is coupled to the input shaft of the gearbox. The drive mechanism is coupled to the output shaft of the gearbox and connected to the pivot arms. The controller selectively controls the motor and coupled gearbox to operate the drive mechanism and connected pivot arms between the first position wherein the cover is retracted, and the second position wherein the cover is extended substantially over the open top. 
     In a preferred embodiment, the motor is a pneumatic motor connected to a source of compressed air. A pneumatic motor avoids the problems associated with hydraulic motors and electrical motors in an outdoor environment. Additionally, the pneumatic motor of the present invention can be connected to the pre-existing air supply of a truck&#39;s brake system. 
     The present roll-out cover system provides several advantages over existing cover systems. For example, the present roll-out cover system can be operated in a power-assist mode or a manual mode. In the power assist mode, a motor is used to drive the pivot arms and cover between an uncovered (or “retracted”) position and a covered (or “substantially extended”) position, or vice versa. In the event the power required to operate the system is not available, the present system can be operated manually. In the power assist mode, the present roll-out cover system can be operated remotely; e.g., from the cab of the truck. 
     Another advantage of the present system is the labor saved by the operator. In the power-assist mode, the work of actuating the roll-out cover is done by the present system, not the operator. The elimination of the physical work also decreases the chance of operator injury. 
     Another advantage of the present invention is its ability to be retrofitted onto existing cover systems. An embodiment of the present invention can be combined with certain manual cover systems to enable them to be operated in a power-assist mode. Because this embodiment advantageously utilizes certain existing components, the modifications and cost to retrofit is minimized. In addition, the retrofit is compatible with the existing manual actuation system. Hence, an existing cover system retrofitted with the present invention can be operated in a power-assist mode or a manual mode. 
     Another advantage of the present invention is that it can be used with a variety of power sources. If a pneumatic motor is employed, compressed air from a source independent of the truck can be used. In the preferred embodiment, however, the pneumatic motor is connected to a source of compressed air portable with the truck; e.g., a brake system air. As a result, the medium that powers the pneumatic motor travels with the truck. 
     These and other objects, features and advantages of the present invention will become apparent in light of the drawings and detailed description of various embodiments of the present invention provided below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an open top dump truck with a roll-out cover in the uncovered position. 
         FIG. 2  is a perspective view showing an open top dump truck with a roll-out cover in the covered position. 
         FIG. 3  is a diagram showing the relationship between the gearbox, the drive mechanism, the motor, and the pivoting arms for the present system example shown in  FIGS. 1 and 2 . 
         FIG. 4  is a perspective view of an embodiment of the present invention system shown in the context of an open top dump truck example, where the motor, gearbox and drive mechanism of the present invention are positioned on the cab of the truck near the front end of the cover. 
         FIG. 5  is a diagram showing the relationship between the gearbox, the drive mechanism, the motor, and the front roller, for the present system example shown in  FIG. 4 . 
         FIG. 6  is a diagram showing the relationship between the controller and the motor for the present invention. 
         FIG. 7  is a diagrammatic view of a coupling used in some embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION 
     Referring to  FIGS. 1-7 , the present invention roll-out cover system  8  is described below in terms of a dump truck application. The dump truck  10  is an example of an open container type truck. The present roll-out cover system can be used with a variety of open container type trucks and is not, therefore, limited to use with dump trucks. 
     The dump truck  10  comprises a front cab  12  and a rear tiltable, open top container  14  having a pair of side walls  16 , a front wall  18 , a rear wall  20 , and a bottom wall  22  defining an interior chamber  24  in which top soil, sand, stone, waste, debris, or similar material may be held for transportation. The rear wall  20  is typically adapted to swing open when the container  14  is tilted upwardly to dump the material therefrom. The container is described as having a front end  30  disposed adjacent the cab  12  of the truck and a rear end  36  disposed oppositely. 
     The present invention roll-out cover system  8  includes a drive mechanism  44  (see  FIGS. 3 and 5 ), a motor  48 , a gearbox  46 , and a controller  50 , operatively connected to a roll-out cover assembly  23 . The roll-out cover assembly  23  includes a cover  26 , a pair of pivot arms  38 , a cover take-up roller  28 , and in some embodiments a crossbar  34 . The cover  26  has a trailing end  25  and a leading end  27  (see  FIG. 2 ). The cover  26  may be made of a canvas material, a polymeric material or any other flexible material easily rollable around the take-up roller  28 . Each of the pivot arms  38  has a pivot end  39  and a free end  41 . One of the pivot arms  38  is mounted adjacent one of the container sidewalls  16 , and the other pivot aim  38  is mounted adjacent the other container side wall  16 . In those embodiments that include a crossbar  34 , the crossbar  34  is disposed between and attached to the free end  41  of each pivot arm  38 . 
     In some embodiments, the take-up roller  28  is attached to the front end of the container  14 , or attached to the truck  10  adjacent the front of the container  14 . In these embodiments, the trailing edge  25  of the cover  26  is attached to the take-up roller  28  and the leading end  27  of the cover  26  is attached to the crossbar  34 . In other embodiments, the take-up roller  28  is either attached to the crossbar  34  or is disposed between the pivot arms  38  in place of the crossbar  34 . In these embodiments, the trailing edge  25  of the cover  26  is attached to container  14  or the truck  10  adjacent the front of the container  14 . The take-up roller  28  and the crossbar  34  (in certain embodiments) extend transversely across the width of the container  14 . The cover  26  has a width and length sufficient to cover at least the open top of the container  14 . 
     When the cover  26  is in the “uncovered” position (or “retracted” position), the pivoting arms  38  are pivoted towards the front end  30  of the container  14 , and substantially all of the cover  26  is rolled around the take-up roller  28 . When the cover  26  is in the “covered” position (or “substantially extended” position), the pivoting arms  38  are pivoted towards the rear end  36  of the container  14  and substantially all of the cover  26  is rolled out from the take-up roller  28 . The take-up roller  28  includes, or operates in combination with, a mechanism operable to cause the cover  26  to roll onto the take-up roller  28 ; e.g., a biasing mechanism. Roll-out cover assemblies the same as, or similar to, that described above are known in the art and will not, therefore, be further described herein. 
     In the embodiment shown in  FIG. 3 , the pivoting arms  38  are joined together by a pivot shaft  40  transversely extending beneath the container  14 . The movement of the pivoting arms  38 , and thus the unrolling and rolling of the cover  26 , is accomplished by driving the pivot shaft  40  with the present invention roll-out cover system  8 . 
     The drive mechanism  44  of the present roll-out cover system  8  includes a drive shaft, which may be the pivot shaft  40  or otherwise operably connected to the pivot shaft  40 . As shown in  FIG. 3 , the drive shaft acts as the pivot shaft  40 . Thus, rotation of the pivot shaft  40  effects pivoting of the pivoting arms  38 . The drive mechanism  44  is connected directly or indirectly to the gearbox  46  as described below. 
     Referring to  FIGS. 3 and 5 , the motor  48  of the present invention roll-out cover system  8  is mounted proximate to the gearbox  46 , on one of the container  14  or the truck  10 . The motor  48  includes an output motor shaft  54  operatively coupled to the gearbox  46 . The motor  48  is preferably a commercially available pneumatic gear motor that is powered by an external air source as will be described below. A vane-type rotary driven motor having a gear reduction assembly with an 80-100 to 1 gear reduction ratio is favored. An example of an acceptable pneumatic gear motor is a WADCO pneumatic gear motor Model No. 33MA-220S1 produced by WADCO, a division of Ingersoll-Rand. 
     The gearbox  46  includes an input shaft  58  and an output shaft  60 , connected to a plurality of gears (not shown). The gears are disposed within a housing  62  having a first side  64  and a second side  66  opposite one another. The input shaft  58  and the output shaft  60  extend outwardly from both the first side  64  and the second side  66 . The gears are arranged to create mechanical advantage for the input shaft  58  relative to the output shaft  60 ; i.e., force transmitted to the input shaft  58  is multiplied through the gears to create a greater force available at the output shaft  60 . The amount of mechanical advantage created by the gears can be varied to suit the application at hand. The input shaft  58  is adapted to receive a selectively removable hand crank (not shown) for manual rotation of the input shaft  58 . When the hand crank is not attached, a knob  72  may be attached to the input shaft  58 . In some embodiments, the gearbox  46  can be changed from a high gear to a low gear, or vice versa, by axially moving the knob  72  and input shaft  58  inward or outward, depending on the initial position of the input shaft  58  and the desired gear. Moving the input shaft  58  axially to change the gear causes the input shaft  58  extending out from both sides of the gearbox housing  62  to move axially. 
     A coupling  68  is used to connect the input shaft  58  of the gearbox  46  to the motor shaft  54  of the motor  48 . In those embodiments where the gearbox  46  can be shifted between gears by axial movement of the input shaft  58 , the coupling  68  accommodates the axial movement of the input shaft  58 . An example of such a coupling  68  is diagrammatically shown in  FIG. 7 . In that embodiment, the coupling  68  includes a coupling housing  94 , a motor shaft flange  96 , a plate  98 , and a spring  100 . The coupling housing  94  has a gearbox end and a motor end for receiving and accommodating the input shaft  58  and the motor shaft  54  respectively. The motor shaft flange  96  is disposed adjacent the motor end of the coupling housing  94  and includes an aperture for slidably receiving the motor shaft  54 . The input shaft  58  is received within and fixed to the gearbox end of the coupling housing  94 . The spring  100  and the plate  98  are disposed within the coupling housing  94  with the spring  100  disposed adjacent the input shaft  58  and the plate  98  disposed adjacent the motor shaft  54 . The plate  98  is retained by the motor shaft flange  96 . Referring to  FIGS. 3 and 5 , the drive mechanism  44  is connected directly or indirectly to the output shaft  60  of the gearbox  46 . A coupling, for example, can be used to directly connect the drive mechanism  44  to the output shaft  60 . A chain drive, for example, can be used to indirectly connect the drive mechanism  44  to the output shaft. The specific means for mechanically connecting the output shaft  60  of the gearbox to the drive mechanism  44  can be varied to suit the application. 
     Referring to  FIG. 6 , the air source  74  for the preferred embodiment pneumatic motor is a portable source provided with the truck  10 . Although an independent compressor (not shown) driven by a power source attached to the truck is acceptable, it is preferred to use an existing air supply from the brake system of the dump truck  10 . The air supply for the emergency brake system is an example of an acceptable air source  74  in most cases. Alternatively, the air source  74  could be a cylinder attached to the container  14 . 
     The controller  50  is provided to control the flow of compressed air to the motor  48 . In a preferred embodiment, the controller  50  includes a valve  76  operatively coupled to the truck&#39;s emergency brake air supply to drive the motor  48 , which in turn drives the gearbox shafts  58  and  60 . In the preferred embodiment, a tee connector  78  is provided within the emergency brake line to tap airflow from the brake system. The tee connector  78  shown in  FIG. 6 , for example, has an input port  80  connected to receive airflow from the air source  74 , a first output port  82  connected to the emergency brake system of the truck  10 , and a second output port  84  connected to the motor  48 . The controller mechanism  50  is provided between the tee connector  78  and the motor  48 . In the preferred embodiment, the controller  50  includes a valve  76 . 
     The valve  76  controls the direction and the amount of air received by the motor  48 . In some embodiments, the valve  76  is a biased valve that provides air passage to the motor  48  only when the valve  76  is manually held in an open position (e.g., by manually holding the lever  86  in an “open” position). Once the lever  86  is released, the lever automatically returns to the “off” position, and the air supply to the motor  48  is terminated. This prevents the valve  76  from being left in a position where the air supply is only connected to the motor  48 . 
     The preferred valve  76  is a three-position valve that includes an “off” position, a first supply position (“cover”), and a second supply position (“uncover”). As noted above, the valve  76  is biased to the “off” position. The lever  86  enables the operator to move the valve  76  between the “off” position and either of the first or second supply positions. The valve  76  is connected to the motor  48  in such a manner that air passing through the valve  76  when the valve is in the first supply position causes the motor  48  to rotate in a first direction (e.g., clockwise). Air passing through the valve  76  when the valve is in the second supply position causes the motor  48  to rotate in a second direction (e.g., counterclockwise). The valve  76  employs one or more air escape ports that utilize mufflers  88  to allow unneeded or excess air to escape. Pneumatic control valves are known in the art and the operation thereof need not be discussed further herein. The valves used in the operation described above are commercially available valves. 
     In alternative embodiments, the valve  76  can be a power-assisted type control valve that utilizes one or more solenoids, for example, to actuate the valve  76  to the first and/or second positions. Such a power-assisted valve may be configured so that the user operates the valve in proximity of the valve, or at a position remote from the valve, such as from the cab  12  of the truck  10 . Even with such alternative valve designs, however, the valve  76  is preferably biased towards the “off” position. 
     In some embodiments, an automatic lubrication unit  90  (e.g., an oil mist lubricator) is provided upstream of the motor  48 , and more preferably upstream of the motor  48  and the valve  76 . The lubrication unit  90  treats the air with a fine oil mist so that the valve  76  and the motor  48  are lubricated so that they can operate efficiently. Automatic lubrication units are known in the art and will not, therefore, be further described herein. 
     In the operation of the present invention, the control valve  76  is moved into the first (or “cover”) valve position to extend the cover  26  over the open top of the container  14 . In the “cover” position, the air source powers the motor  48 , which in turn drives the gearbox  46  and attached drive mechanism  44 . As a result, the pivot aims  38  are pivoted towards the rear end  36  of the container  14 . The take-up roller  28  permits the cover  26  to roll out, but maintains a tension on the cover  26 . Once the leading end of the cover  26  is disposed adjacent the rear end  36  of the container  14 , the valve lever  86  is released and the valve  76  automatically returns to the “off” position. To uncover the container  14 , the valve  76  is moved to the “uncover” position. In the “uncover” position, the air source powers the motor  48 , and therefore the attached gearbox  46  and drive mechanism  44 , in a rotational direction opposite that taken in the “cover” operation. As a result, the pivoting arms  38  are pivoted towards the front end  30  of the container  14 , to roll-up the cover  26 . The take-up roller  28  cooperates with the reverse pivoting of the aims  38  to roll the cover  26  around the take-up roller  28 . The tension effected on the cover  26  by the take-up roller  28  facilitates the roll-up process. The tension also helps to maintain the pivot aims  38  in the “uncovered” position after the cover  26  has been rolled up onto the take-up roller  28 . Once the cover  26  is rolled up, the valve lever  86  is released and the valve  76  automatically returns to its “off” position. 
     If an air source is not available to power the motor  48 , the present invention system  8  can be manually operated with a hand crank. The hand crank is attached to the section of input shaft  58  extending out from the second side  66  of the gearbox housing  62  and cranked to rotate the pivot arms  38  and attached cover  26 . The ability of the present system  8  to be manually operated provides significant advantage in situations where no air supply is available, and consequently more utility overall. 
     In the embodiment wherein the gearbox  46  can be shifted into a high gear or a low gear, the operation of the present system  8  is the same as that described above with the addition that the gear selection may be changed to suit the situation at hand. Specifically, the gearbox  46  can be shifted from one of the high gear or low gear to the other of the high gear or low gear by axially moving the input shaft  58 . If, for example, the knob  72  and attached input shaft  58  are pushed inward to change gears, the input shaft  58  moves axially against the pressure of the spring  100  within the coupling  68 . The coupling housing  94  moves axially along the motor shaft  54 , compressing the spring  100 . When the operator moves the knob  72  and input shaft  58  back into the original gear, the spring  100  acts against the input shaft  58  and returns the input shaft  58  to the first axial position associated with the original gear. 
     Now referring to  FIGS. 4 and 5 , in an alternative embodiment of the present invention, the present system  8  is operably connected to the take-up roller  28 . The output shaft  60  of the gearbox  46  is connected to the take-up roller  28 . The motor  48  is connected to the input shaft  58  in a manner the same as, or similar to, that described above. Rotation of the take-up roller  28  causes the cover  26  to be rolled in or out. 
     In this embodiment, the rolling-out or in of the cover  26  is conducted with the assistance of the pivoting arms  38 . The pivoting arms  38  are biased towards the rear end  36  of the container  14 . When the take-up roller  28  is rotated to roll out the cover  26 , spring means (not shown) connected to the pivoting aims  38  help pivot the arms  38  towards the rear end  36  of the container  14  and maintain the cover  26  substantially taut. When the take-up roller  28  is rotated to roll in the cover  26 , the power of the take-up roller  28  counteracts the spring means. The pivoting arms  38  are pivoted towards the front end  30  of the container  14  and held under tension when the cover  26  is completely rolled around the take-up roller  28 . Various means for biasing the pivoting arms  38  are known, and are not discussed further herein. The gearbox  46 , motor  48  and controller mechanism  50  of  FIGS. 4-5  operate in the same manner as discussed above with respect to  FIGS. 1-3 . 
     An embodiment of the present invention roll-out cover system  8  is a retrofit kit for use with certain manual cover operating mechanisms to enable them to be operated in a power-assist mode. The retrofit kit includes a motor  48 , a controller  50 , and in some instances a gearbox  46 . When the retrofit kit is combined with an existing manual cover operating mechanism that includes a gearbox, the motor  48  is coupled with the existing gearbox. The motor  48  and controller  50  are connected to an air source  74  as described above. When the retrofit kit is combined with an existing manual cover operating mechanism that does not include a gearbox, the gearbox  46  is coupled with the drive mechanism for the pivot arms  38  (or the take-up roller  28 ), and the motor  48  is coupled with the gearbox  46 . The motor  48  and controller  50  are connected to an air source  74  as described above. In both instances, the operation of the retrofitted system is the same as or similar to that described above. 
     Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail thereof may be made without departing from the spirit and scope of the invention.