Patent Publication Number: US-11649744-B2

Title: Capstan-driven air pump system for opening and closing a longitudinal railcar door

Description:
PRIORITY 
     This application claims priority, under 35 U.S.C. § 119(e), to U.S. Provisional Patent Application No. 62/926,939 filed Oct. 28, 2019, titled “CAPSTAN-DRIVEN AIR PUMP SYSTEM FOR OPENING AND CLOSING A LONGITUDINAL RAILCAR DOOR,” which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     Particular embodiments relate generally to railcars, and more particularly to a capstan-driven air pump system for opening and closing a longitudinal door of a railcar. 
     BACKGROUND 
     Hopper-type railcars are typically used to transport lading. The lading is loaded through the top of the car for transport to a destination where it is discharged through an opening at the bottom of the car. Many hopper-type railcars use sliding gate assemblies mounted on the discharge openings, to control the discharge of the lading. Each sliding gate assembly typically includes a door plate and a drive for moving the plate between open and closed positions. When the plate is in the closed position, the plate covers the railcar opening and prevents the lading from discharging through the opening. On the other hand, when the plate is in the open position, lading may freely discharge through the opening. 
     Such sliding gate assemblies are typically controlled mechanically, with the use of a capstan. Here, the capstan is used to provide rotation and torque, which is converted to a sliding motion of the gate through the use of a rack and pinion drive. Accordingly, many unloading facilities are set up for capstan operations, including some that use sophisticated robotic and visual systems. 
     Longitudinal door systems have also been developed for hopper-type railcars. Each longitudinal door system typically includes one or more doors attached to a sliding longitudinal beam via struts. When the longitudinal beam travels in one direction, the doors may be rotated opened by the struts. When the longitudinal beam travels in the other direction, the doors may be rotated closed by the struts. 
     Such door systems often use a pneumatic cylinder to move the longitudinal beam. However, many conventional unloading facilities, already equipped with capstans, may be reluctant to provide trackside air to operate such pneumatic cylinders. Accordingly, some implementations of longitudinal door systems have sought to employ mechanical devices, rather than pneumatic cylinders, to move the longitudinal beams of the door systems. 
     SUMMARY 
     This disclosure contemplates a capstan-driven air pump system for opening and closing a longitudinal door of a railcar that addresses one or more of the above technical difficulties. The system uses existing capstan infrastructure, generally available at conventional railcar unloading facilities, coupled to an air pump or compressor, to provide air pressure and volume to a pneumatic cylinder. This air pressure and volume is used to move the piston of the cylinder, generating linear motion that may be used to move the longitudinal beam of a longitudinal door system, thereby opening or closing the doors of the longitudinal door system. 
     In certain embodiments, a longitudinal door system of a railcar may be operated either by using trackside air coupled to the pneumatic cylinder, or by using a mechanical capstan drive coupled to an air pump or compressor, which may then provide air pressure and volume to the pneumatic cylinder. Accordingly, railcars equipped with longitudinal door systems may easily be incorporated into existing railcar fleets, without a need for existing unloading facilities to provide trackside air, to accommodate such railcars. Instead, the capstan-driven air pump system of the present disclosure may allow for an industry transition period from capstan-driven railcar doors to air actuated doors. 
     Certain embodiments of the capstan-driven air pump system may provide one or more technical advantages. For example, an embodiment may enable the use of existing capstan drives to operate longitudinal railcar doors. As another example, an embodiment may allow for an industry transition period, where companies may incorporate railcars that include longitudinal door systems into their railcar fleets, without a worry that conventional unloading facilities will not be able to accommodate such railcars. As a further example, an embodiment may capture excess air pressure and volume in a reservoir, which may later be used to open and/or close the longitudinal doors of a railcar when access to either a capstan or trackside air is unavailable. Certain embodiments may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
         FIGS.  1 A and  1 B  illustrate an example longitudinal door system; 
         FIG.  2    illustrates an example embodiment of the capstan-driven air pump system; 
         FIG.  3    illustrates an example operation of the capstan-driven air pump system of  FIG.  2   , in which an air pump, powered by the capstan drive, is moving a piston of a pneumatic cylinder in a first direction; 
         FIG.  4    illustrates an example operation of the capstan-driven air pump system of  FIG.  2   , in which a pressure relief valve is used to remove excess pressure generated by the air pump; 
         FIG.  5    illustrates an example operation of the capstan-driven air pump system of  FIG.  2   , in which the direction of the capstan is reversed, causing the air pump to move the piston of the pneumatic cylinder in a second direction, opposite the first direction; 
         FIGS.  6 A and  6 B  illustrate an example embodiment of the capstan-driven air pump system in which a valve may be used to control the direction of movement of a piston of a pneumatic cylinder; 
         FIGS.  7 A and  7 B  illustrate an example embodiment of the capstan-driven air pump system of  FIG.  6   , in which a device may be used to control the valve, based on the direction of rotation of the capstan; 
         FIG.  8    illustrates another example embodiment of the capstan-driven air pump system, in which the capstan drive is operated in a first direction, to cause the piston of the pneumatic cylinder to move in the first direction; 
         FIG.  9    illustrates the example embodiment of the capstan-driven air pump system of  FIG.  8   , in which the capstan drive is operated in the reverse direction, to cause the piston of the pneumatic cylinder to move in the second direction; 
         FIG.  10    illustrates an example embodiment of the capstan-driven air pump system in which excess air pressure and volume may be redirected to an air reservoir; 
         FIG.  11    illustrates an example embodiment of the capstan-driven air pump system in which the doors of the railcar may be opened using a capstan drive positioned on either side of the railcar; 
         FIG.  12    illustrates an example manner in which capstan drives on either side of a railcar may be connected to one another; 
         FIG.  13    presents a flowchart illustrating an example manner by which a capstan drive may be used to power an air pump to open the longitudinal doors of a railcar; and 
         FIG.  14    presents a flowchart illustrating an example manner by which a capstan drive may be used to power an air pump to close the longitudinal doors of a railcar. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure and its advantages are best understood by referring to  FIGS.  1  through  14    of the drawings, like numerals being used for like and corresponding parts of the various drawings. 
       FIGS.  1 A and  1 B  illustrate an example longitudinal door system  100  that may be used with the capstan-driven air pump system of the present disclosure. Such a longitudinal door system may be included in railcars such as hopper and gondola cars. As illustrated in  FIGS.  1 A and  1 B , longitudinal door system  100  may include one or more doors  125  attached to a sliding longitudinal beam  120  via struts  130 . For example, longitudinal door system  100  may include a pair of doors  125   a  and  125   b . In particular embodiments, longitudinal door system  100  may include any number of struts  130 . When longitudinal beam  120  travels in a first direction, doors  125   a  and  125   b  may be rotated open by struts  130 , as illustrated in  FIG.  1 B . When longitudinal beam  120  travels in a second direction, opposite the first direction, doors  125   a  and  125   b  may be rotated closed by struts  130 , as illustrated in  FIG.  1 A . 
     As illustrated in  FIGS.  1 A and  1 B , the longitudinal door system may be coupled to a pneumatic cylinder  105 . Air pressure and volume may be applied to pneumatic cylinder  105  to move piston  115  in pneumatic cylinder  105 . Piston rod  110  may be coupled to longitudinal beam  120 , such that movement of piston  115  in pneumatic cylinder  105  causes piston rod  110  to move longitudinal beam  120 . In particular embodiments, pneumatic cylinder  105  may be operated in any suitable manner. For example, air volume may be applied to pneumatic cylinder  105  to generate pressure to move piston  115 . Alternatively, air volume may be removed from pneumatic cylinder  105  to generate a vacuum to move piston  115 . Such operations of pneumatic cylinder  105  is described in further detail below. 
       FIG.  2    illustrates an example embodiment of the capstan-driven air pump system of the present disclosure. As illustrated in  FIG.  2   , the capstan-driven air pump system includes a capstan drive  205 , air pump or compressor  210 , and pneumatic cylinder  105 . Air pump or compressor  210  includes air inlet/outlet  220 . Pneumatic cylinder  105  includes piston  115  and piston rod  110 . In certain embodiments, the capstan-driven air pump system may also include pressure relief valve  230  and/or pressure gauge  235 . 
     Air pump/compressor  210  and pneumatic cylinder  105  may be mounted on the underside of a railcar to operate a longitudinal door system  100  of the railcar. On the other hand, capstan drive  205  may be located externally to the railcar. For example, capstan drive  205  may be located trackside at a conventional railcar unloading facility. 
     Pneumatic cylinder  105  and air pump/compressor  210  may be separate from one another. For example, pneumatic cylinder  105  and air pump/compressor  210  may be separate pieces of equipment, mounted at different locations on the underside of a railcar, and coupled to one another through hose/pipe  225 . The use of air pump/compressor  210  separate from pneumatic cylinder  105  may provide flexibility in where air pump/compressor  210  may be mounted. For example, air pump/compressor  210  may be mounted in any convenient location for access for use or service. 
     As illustrated in  FIG.  2   , initially, when capstan drive  205  is not connected to air pump/compressor  210 , there is no air pressure in the system. This is indicated by pressure gauge  235  reading zero.  FIG.  2    additionally illustrates piston  115  of pneumatic cylinder  105  in a door-closed position (i.e., piston  115  is positioned within pneumatic cylinder  105  near a first end  215  of pneumatic cylinder  105  that is coupled to air pump  210  (through hose/pipe  225 ), and far from a second end  240  of pneumatic cylinder  105 , through which piston rod  110  moves). As illustrated in  FIG.  1 A , such positioning of piston  115  corresponds to doors  125   a  and  125   b  being in a closed position. 
       FIG.  3    illustrates an example of the operation of the capstan-driven air pump system illustrated in  FIG.  2   . As illustrated in  FIG.  3   , during operation of the capstan-driven air pump system, capstan drive  205  is mechanically engaged to air pump/compressor  210 . Capstan drive  205  may be actuated such that rotation and torque from the capstan rotates the air pump or compressor  210 , to generate air pressure and volume. As illustrated with pressure gauge  235 , positive air pressure is now being supplied to pneumatic cylinder  105 . This air may be delivered to first end  215  of pneumatic cylinder  105 , to move piston  115  in a first direction (e.g., the direction away from first end  215  of pneumatic cylinder  105 ). The linear motion of piston  115  (and correspondingly piston rod  110 ) may be used to open the longitudinal doors of the railcar, as illustrated in  FIG.  1 B . 
       FIG.  4    illustrates an example operation of the capstan-driven air pump system of  FIG.  2   , in which piston  115  has reached second end  240  (i.e., the end opposite to first end  215 ) of pneumatic cylinder  105 . As illustrated in  FIG.  4   , in certain embodiments, capstan drive  205  may continue to operate even after piston  115  has reached second end  240  of pneumatic cylinder  105  (i.e., corresponding to the door motion of the longitudinal door system having stopped). In such embodiments, air pump/compressor  210  may generate excessive air pressure in the system. In certain such embodiments, the design of air pump/compressor  210  may be such that it can withstand any excessive pressure that may be generated. In certain other embodiments, and as illustrated in  FIG.  4   , the system may be designed such that excessive pressure may be exhausted to the atmosphere, such as through pressure relief valve  230 . 
       FIG.  5    illustrates an example of the operation of the capstan-driven air pump system illustrated in  FIG.  2   , in which the direction of operation of capstan drive  205  has been reversed, as compared to the operation illustrated in  FIGS.  3  and  4   . As illustrated by pressure gauge  235 , reversing the direction of operation of capstan drive  205  leads to air pump/compressor  210  removing air from the system, generating a vacuum. Supplying this vacuum to pneumatic cylinder  105  causes piston  115  to move in a second direction, opposite the first direction, toward first end  215  of pneumatic cylinder  105 . This movement of piston  115  may continue until piston rod  110  is in its fully retracted position within pneumatic cylinder  105 . 
     In certain embodiments, and as illustrated in  FIGS.  6 A and  6 B , a valve  300  may be used to control the direction of movement of piston  115  in pneumatic cylinder  105 . Valve  300  may be operated using lever  305 .  FIG.  6 A  presents an example in which lever  305  on valve  300  is in a first position. This position allows air from air pump or compressor  210  to be directed to first end  215  of pneumatic cylinder  105  to move piston  115  in a first direction (e.g., the direction away from first end  215  of pneumatic cylinder  105 ), to open the railcar doors. On the other hand,  FIG.  6 B  presents an example in which lever  305  is in a second position on valve  300 . This second position directs air from air pump or compressor  210  to the opposite end  240  of piston  115 , to move piston  115  in a second direction (e.g., the direction toward first end  215  of pneumatic cylinder  105 ), to close the railcar doors. Valve  300  may be manually operated or controlled in any other suitable manner, with or without lever  305 . In certain embodiments, this allows the door on the railcar to be opened or closed without having to reverse the direction of the capstan drive. 
       FIGS.  7 A and  7 B  present an example illustrating the use of a device  320  to operate valve  310 , in certain embodiments. As illustrated in  FIGS.  7 A and  7 B , device  320  is located between capstan drive  205  and air pump/compressor  210 . When capstan drive  205  operates in a first rotational direction, as illustrated in  FIG.  7 A , air pump or compressor  210  also operates in this first rotational direction. Device  320  transfers the torque and direction of rotation from capstan drive  205  to air pump or compressor  210  and signals valve  310  to direct air to first side  215  of cylinder  105  to move piston  115  in a first direction (e.g., the direction away from first end  215  of pneumatic cylinder  105 ), to open the railcar doors. 
     On the other hand,  FIG.  7 B  presents an example in which the direction of capstan drive  205  is reversed. As illustrated in  FIG.  7 B , in certain embodiments, device  320  may reverse the direction of rotation delivered to air pump or compressor  210  and transmit the torque to air pump/compressor  210  from capstan drive  205  so that air pump/compressor  210  continues to create air volume and pressure. Device  320  may also direct valve  310  to direct air to the opposite end  240  of cylinder  105  to move piston  115  in a second direction (e.g., the direction toward first end  215  of pneumatic cylinder  105 ), to close the railcar doors. This allows capstan drive  205  to be operated in a first direction to open the railcar doors and in a second direction to close the railcar doors, where air pressure is used in both situations to open and close the railcar doors. 
       FIG.  8    illustrates another example embodiment of the capstan-driven air pump system of the present disclosure. As illustrated in  FIG.  8   , in certain embodiments, air pump/compressor  210  may be coupled to pneumatic cylinder  105  at both first end  215  and second end  240  of pneumatic cylinder  105 . For example, a first hose/pipe  225  may connect air pump/compressor  210  to first end  215  of pneumatic cylinder  105  and a second hose/pipe  605  may connect air pump/compressor  210  to second end  240  of pneumatic cylinder  105 . 
     As illustrated in  FIG.  8   , when capstan drive  205  is operated in a first direction, air pump/compressor  210  may pump air from second hose/pipe  605  into first hose/pipe  225 . Accordingly, air pressure and volume are applied to the first side of piston  115  (e.g., the side of piston  115  closest to first side  215  of pneumatic cylinder  105 ), while a vacuum is applied to the second side of piston  115  (e.g., the side of piston  115  closest to second side  240  of pneumatic cylinder  105 ). This causes piston rod  110  to move in a first direction, away from first end  215 , thereby opening doors  125  of longitudinal door system  100 , as illustrated in  FIG.  1 B . 
       FIG.  9    illustrates the example embodiment of the capstan-driven air pump system of  FIG.  8   , in which capstan drive  205  is operated in the opposite direction. As illustrated in  FIG.  9   , when capstan drive  205  is operated in the opposite direction from that illustrated in  FIG.  8   , air pump/compressor  210  may pump air from first hose/pipe  225  into second hose/pipe  605 . Accordingly, air pressure and volume are applied to the second side of piston  115  (e.g., the side of piston  115  closest to second side  240  of pneumatic cylinder  105 ), while a vacuum is applied to the first side of piston  115  (e.g., the side of piston  115  closest to first side  215  of pneumatic cylinder  105 ). This causes piston rod  110  to move in a second direction, opposite the first direction, and away from second end  240 , thereby closing doors  125  of longitudinal door system  100 , as illustrated in  FIG.  1 A . 
       FIG.  10    illustrates an example embodiment of the capstan-driven air pump system of the present disclosure, in which excess air pressure and volume may be redirected to a secondary system. For example, excessive pressure and air volume released through pressure relief valve  230  may be directed into reservoir  805 . In certain embodiments, reservoir  805  may be coupled to a pressure relief valve  815 , to help ensure that excessive pressure does not accumulate within reservoir  805 . 
     In certain embodiments, the air stored in reservoir  805  may be used to open/close the doors of longitudinal door system  100 . For example, as illustrated in  FIG.  10   , in certain embodiments, valve  820  may be used to direct the air stored in reservoir  805  to pneumatic cylinder  105 . 
     Valve  820  may be any suitable type of valve to control the flow of air. For example, valve  820  may be a manual valve. As another example, valve  820  may be a 2-way valve, as illustrated in  FIG.  10   , such that valve  820  may be used to direct the air stored in reservoir  805  along first hose/pipe  825  to first end  215  of pneumatic cylinder  105 , or along second hose/pipe  830  to second end  240  of pneumatic cylinder  105 . 
     When valve  820  is used to direct air stored in reservoir  805  to first end  215  of pneumatic cylinder  105 , the air pressure and volume applied to pneumatic cylinder  105  may move piston  115  in the first direction (e.g., the direction away from first end  215  of pneumatic cylinder  105 ). This linear motion of piston  115  (and correspondingly of piston rod  110 ) may be used to move the longitudinal doors of the railcar to an open position, as illustrated in  FIG.  1 B . 
     Alternatively, when valve  820  is used to direct air stored in reservoir  805  to second end  215  of pneumatic cylinder  105 , the air pressure and volume applied to pneumatic cylinder  105  may move piston  115  in the second direction, opposite the first direction, and toward first end  215  of pneumatic cylinder  105 . This linear motion of piston  115  (and correspondingly of piston rod  110 ) may be used to move the longitudinal doors of the railcar to an open position, as illustrated in  FIG.  1 A . 
     In certain embodiments, in addition to excessively pressurized air released through pressure relief valve  230  and directed into reservoir  805 , trackside air may be used to fill reservoir  805 . For example, as illustrated in  FIG.  10   , trackside air may be directed into reservoir  805  through hose/pipe/line  810 . 
     The use of reservoir  805  may enable the gates or doors of a railcar to be operated at a first unloading facility using a capstan-driven air pump or compressor  210 , where excess pressure generated by the capstan-driven air pump/compressor  210  is further used to pressurize reservoir  805 . Then, at a second unloading facility, the gates or doors of the railcar may be operated using either a capstan-driven air pump/compressor  210  or reservoir  805 , along with valve  820 . 
       FIG.  11    illustrates an example embodiment of the capstan-driven air pump system in which the doors of the railcar may be opened using a capstan drive positioned on either side of the railcar. As illustrated in  FIG.  11   , a first capstan drive  205   a  may be positioned on a first side of the railcar, and a second capstan drive  205   b  may be positioned on a second side of the railcar, opposite the first side. 
     Each capstan drive  205   a  and  205   b  is mechanically engaged to gear box  910 . Gear box  910  is used to convert rotation generated by capstan drives  205   a  and  205   b  to rotation of component  915 , used to drive air pump/compressor  210 . This disclosure contemplates that gear box  910  may include any suitable components to convert rotation of the capstan drive in a first direction to rotation of component  915 , connected to air pump/compressor  210 , in a second direction. 
     In certain embodiments, gear box  910  may also allow the input rotational speed for first capstan drive  205   a  and/or second capstan drive  205   b  to be different than the rotational speed of component  915 , connected to air pump/compressor  210 . This disclosure contemplates that generating this rotational speed difference may be accomplished in any suitable manner. For example, in certain embodiments, internal gear ratios, pulleys, or a continuously variable system may be used. This may be desirable to permit torque or speed limiting devices to protect various system components, such as over-speed protection for air pump/compressor  210 . 
       FIG.  12    illustrates an example manner by which first capstan drive  205   a  and second capstan drive  205   b , located on either side of a railcar, may be connected to one another inside gear box  910 . As illustrated in  FIG.  12   , first capstan drive  205   a  and second capstan drive  205   b  may be connected to one another using first gear  1005   a  and second gear  1005   b . This may permit clockwise rotation on each side of the railcar to create rotational motion of component  915  in the same direction, to drive air pump/compressor  210 . 
       FIG.  13    presents a flowchart illustrating an example manner by which a capstan drive may be used to power an air pump to open the longitudinal doors of a railcar. In step  1305 , capstan drive  205  is rotated in a first rotational direction. In step  1310 , capstan drive  205  supplies rotation in the first rotational direction to air pump/compressor  210 . In step  1315 , air pump/compressor  210  supplies air pressure and air volume to first end  215  of pneumatic cylinder  105 . In step  1320 , piston  115  of pneumatic cylinder  105  moves in a first direction towards second end  240  of pneumatic cylinder  105 . In step  1325 , longitudinal beam  120 , coupled to piston rod  110 , moves in the first direction. Finally, in step  1330 , doors  125   a  and  125   b  open. 
     Modifications, additions, or omissions may be made to method  1300  depicted in  FIG.  13   . Method  1300  may include more, fewer, or other steps. For example, steps may be performed in parallel or in any suitable order. This disclosure contemplates that the steps may be performed by an individual, a machine, or any suitable device. 
       FIG.  14    presents a flowchart illustrating an example manner by which a capstan drive may be used to power an air pump to close the longitudinal doors of a railcar. In step  1405 , capstan drive  205  is rotated in a second rotational direction, opposite the first rotational direction. In step  1410 , capstan drive  205  supplies rotation in the second rotational direction to air pump/compressor  210 . In step  1415 , air pump/compressor  210  removes air pressure and air volume from first end  215  of pneumatic cylinder  105 . In step  1420 , piston  115  of pneumatic cylinder  105  moves in a second direction, opposite the first direction, towards first end  215  of pneumatic cylinder  105 . In step  1425 , longitudinal beam  120 , coupled to piston rod  110 , moves in the second direction. Finally, in step  1430 , doors  125   a  and  125   b  close. 
     Modifications, additions, or omissions may be made to method  1400  depicted in  FIG.  14   . Method  1400  may include more, fewer, or other steps. For example, steps may be performed in parallel or in any suitable order. This disclosure contemplates that the steps may be performed by an individual, a machine, or any suitable device. 
     While discussed in terms of an embodiment for a hopper railcar, this disclosure contemplates that embodiments of the capstan-driven air pump system may be applied to other types of railcars, including, for example, gondola railcars. Furthermore, while discussed in terms of operating a pneumatic cylinder configured to push a beam to open longitudinal doors of a hopper railcar, this disclosure contemplates that the capstan-driven air pump system of the present disclosure may be used to open and close a variety of different doors and/or gates of railcars, including, for example, sliding gates. 
     As can be seen by one established in the art of railcar design, there are a number of ways that the capstan-driven air pump of the present disclosure may be incorporated into a railcar, both as a standalone system and in combination with other gate and door operating systems. For example, the capstan-driven air pump may be used in combination with hot shoe and/or manual operations. 
     Although the present disclosure includes several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present disclosure encompass such changes, variations, alterations, transformations, and modifications as falling within the scope of this disclosure.