Apparatus for controlling operation of a railcar discharge gate assembly having a lost motion mechanism for unlocking the gate prior to movement

Abstract

An apparatus for controlling operation of a railcar discharge gate assembly including a frame defining a discharge opening with a gate slidably arranged on the frame for movement along a predetermined path of travel between open and closed positions. The apparatus of the present invention includes an operating shaft rotatably supported on the frame for selectively moving the gate between open and closed positions in response to rotation of the shaft. A lock assembly is carried on the frame and is operably coupled to the operating shaft. The lock assembly includes a displacable stop member which, when the gate is closed, extends into the path of travel of the gate to prevent movement of the gate relative to the frame, and which moves in timed relation relative to movement of the gate such that upon rotation of the operating shaft to move the gate to an open position the stop member is automatically removed from the path of travel of the gate prior to movement of the gate toward an open position. The questions raised in reexamination request No. 90/004,286, filed Jun. 24, 1996, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).

What is claimed is: 
     
       1. . .An.!. .Iadd.A gate control .Iaddend.apparatus . .for controlling operation of a.!. .Iadd.and .Iaddend.railway hopper car discharge gate assembly including a frame defining a generally rectangular discharge opening with a generally rectangular discharge gate mounted on said frame for movement between open and closed positions along a predetermined path of travel, said apparatus comprising: an operating shaft rotatably supported on said frame adjacent a rear end of said gate, said operating shaft being connected to said gate whereby said gate slidably moves forwardly and rearwardly between .Iadd.the .Iaddend.open and closed positions in response to rotation of said operating shaft;   a lock assembly carried on said frame and including a displacable stop member which, when said gate is in its closed position, extends into the predetermined path of travel to positively engage an edge of said gate thereby preventing movement of the gate relative to said frame; and   wherein a drive is provided between said lock assembly stop member and said operating shaft for positively displacing said stop member from said path of travel of said gate upon rotation of said operating shaft prior to movement of the gate toward . .an.!. .Iadd.the .Iaddend.open position.   
     
     
       2. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 1 wherein said operating shaft is connected to said gate through pinion gears arranged upon said operating shaft and which intermesh with racks fitted to an underside of said gate. 
     
     
       3. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 1 wherein said stop member is pivotally mounted on said frame for vertical movement about a fixed generally horizontal axis extending generally parallel to said operating shaft. 
     
     
       4. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 1 wherein said drive Includes a cam mounted on said operating shaft for positively displacing said stop member from the path of travel of said gate upon rotation of said operating shaft. 
     
     
       5. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 1 wherein said stop member is resiliently urged by a spring toward an engaging position with said gate. 
     
     
       6. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 1 wherein said stop member is provided with a counterweight for naturally causing said stop member to be urged toward engagement with said gate. 
     
     
       7. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 1 wherein said drive includes a lost motion mechanism for permitting a predetermined range of free rotation of the operating shaft prior to movement of said gate toward . .an.!. .Iadd.the .Iaddend.open position. 
     
     
       8. . .An.!. .Iadd.A gate control .Iaddend.apparatus . .for controlling operation of a.!. .Iadd.and .Iaddend.railway hopper car discharge gate assembly including a frame defining a discharge opening with a discharge gate slidably arranged on said frame for movement along a predetermined . .path.!. .Iadd.plane .Iaddend.of travel between open and closed positions, said apparatus comprising: an operating shaft supported for rotation by said frame and operable to selectively move the gate between .Iadd.the .Iaddend.open and closed positions in response to rotation of said shaft; and   a lock assembly carried on said frame and operably coupled to said operating shaft, said lock assembly including a stop member which, when the gate is in . .its.!. .Iadd.the .Iaddend.closed position, extends into said . .path.!. .Iadd.plane .Iaddend.of travel to prevent movement of the gate relative to the frame, and wherein said stop member is driven in timed relation relative to movement of said gate such that upon rotation of said operating shaft to move said gate to . .an.!. .Iadd.the .Iaddend.open position said stop member is automatically removed from the . .path.!. .Iadd.plane .Iaddend.of . .movement.!. .Iadd.travel .Iaddend.of the gate prior to movement of the gate toward . .its.!. .Iadd.the .Iaddend.open position.   
     
     
       9. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 8 wherein said operating shaft is coupled to said gate through a rack and pinion drive mechanism arranged beneath the predetermined . .path.!. .Iadd.plane .Iaddend.of travel of said gate. 
     
     
       10. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 9 wherein a lost motion mechanism is provided between said operating shaft and said rack and pinion drive mechanism for permitting rotation of said operating shaft through a predetermined range of rotation prior to imparting an opening movement to said gate. 
     
     
       11. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 8 wherein said stop member is mounted on said frame for generally vertical movement relative to the . .path.!. .Iadd.plane .Iaddend.of travel of said gate. 
     
     
       12. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 8 wherein said stop member of said locking assembly is biased into the . .path.!. .Iadd.plane .Iaddend.of travel of said gate. 
     
     
       13. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 8 further including an actuator rotatable with and in response to rotation of said operating shaft for positively removing said stop member from the . .path.!..Iadd.plane .Iaddend.of . .movement.!. .Iadd.travel .Iaddend.of the gate. 
     
     
       14. . .An.!. .Iadd.A gate control .Iaddend.apparatus . .for controlling operation of a.!. .Iadd.and .Iaddend.railway car discharge gate assembly including a frame defining a generally rectangular discharge opening with a generally rectangular discharge gate mounted on said frame for movement along a predetermined path of travel extending between a forward closed position and a rearward open position, said apparatus comprising: an operator controlled actuation assembly for moving said gate along its predetermined path of travel between .Iadd.the .Iaddend.open and closed positions, said actuation assembly including an operating shaft mounted on said frame for rotation about a fixed axis extending generally parallel to a rear edge of said gate and wherein said operating shaft is operably coupled to said gate;   a lock assembly carried on said frame, said lock assembly including a stop member which, when said gate is in its forward closed position, is positioned to wedge against an edge of the gate thereby preventing movement of the gate relative to the frame and which is displacable to a released position to permit said gate to move relative to said frame toward . .an.!. .Iadd.the .Iaddend.open position;   and wherein a drive including a lost motion mechanism is arranged between said operating shaft and said stop member for automatically effecting, in sequential order and in response to rotation of said operating shaft, displacement of said stop member from the path of travel of said gate and movement of said gate toward . .an.!. .Iadd.the .Iaddend.open position.   
     
     
       15. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 14 wherein said actuation assembly further includes a rack and pinion drive assembly comprised of a pair of laterally spaced pinion gears mounted on said operating shaft for engagement with a pair of laterally spaced racks fixed to an undersurface of said gate. 
     
     
       16. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 14 wherein said stop member of said lock assembly includes a lever pivotally mounted on the frame for rocking movement about an axis extending generally parallel to said operating shaft, with one end of said lever being adapted to positively engage and wedge against said gate edge. 
     
     
       17. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 16 wherein said lock assembly further includes a spring member for resiliently urging said lever into engagement with said gate. 
     
     
       18. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim . .14.!. .Iadd.16 .Iaddend.wherein said drive further includes a cam mounted on and for rotation with said operating shaft for engaging said lever in a manner positively displacing the lever to a released position in response to rotation of said operating shaft. 
     
     
       19. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 14 wherein said operating shaft is operably coupled to said gate through a rack and pinion assembly, and wherein said lost motion mechanism includes a specifically configured slot defined by pinions of said rack and pinion assembly for allowing said operating shaft to rotate through a predetermined angle of rotation prior to imparting motion to said pinions and thereby movement of the gate. 
     
     
       20. The .Iadd.gate control .Iaddend.apparatus .Iadd.and railway hopper car discharge gate assembly .Iaddend.according to claim 19 wherein said lost motion mechanism incorporates a dwell period during which a cam member carried on the operating shaft is rotated into engagement with the stop member and an actuating period during which the cam member is rotated to positively move the stop member to a released position prior to movement of the gate toward . .an.!. .Iadd.the .Iaddend.open position. .Iadd.21. A gate control apparatus and railway hopper car discharge gate assembly including a frame defining a generally rectangular discharge opening with a generally rectangular discharge gate mounted on said frame for movement between open and closed positions along a predetermined path of travel, said apparatus comprising: an operating shaft rotatably supported on said frame adjacent an end of said opening, said operating shaft being connected to said gate whereby said gate slidably moves between the open and closed positions in response to rotation of said operating shaft;   a lock assembly including a displacable stop member which, when said gate is in its closed position, prevents movement of the gate relative to said frame; and   wherein a drive is provided between said lock assembly stop member and said operating shaft for positively displacing said stop member prior to movement of the gate. .Iaddend..Iadd.22. The gate control apparatus and railway hopper car discharge gate assembly according to claim 21 wherein said operating shaft is connected to said gate through pinion gears arranged upon said operating shaft and which intermesh with racks fitted to an underside of said gate. .Iaddend..Iadd.23. The gate control apparatus and railway hopper car discharge gate assembly according to claim 21 wherein said stop member is pivotally mounted for vertical movement about a fixed generally horizontal axis extending generally parallel to said operating shaft. .Iaddend..Iadd.24. The gate control apparatus and railway hopper car discharge gate assembly according to claim 21 wherein said drive includes a cam mounted on said operating shaft for positively displacing said stop member upon rotation of said operating shaft. .Iaddend..Iadd.25. The gate control apparatus and railway hopper car discharge gate assembly according to claim 21 wherein said lock assembly further comprises a spring for resiliently urging said stop member into a position to prevent movement of said gate. .Iaddend..Iadd.26. The gate control apparatus and railway hopper car discharge gate assembly according to claim 21 wherein said drive includes a lost motion mechanism for permitting a predetermined range of free rotation of the operating shaft prior to movement of said gate. .Iaddend..Iadd.27. A gate control apparatus and railway hopper car discharge gate assembly including a frame defining a discharge opening with a discharge gate slidably arranged on said frame for movement along a predetermined plane of travel between open and closed positions, said apparatus comprising:   an operating shaft supported for rotation by said frame and operable to selectively move the gate between the open and closed positions in response to rotation of said shaft; and   a lock assembly operably coupled to said operating shaft, said lock assembly including a stop member which, when the gate is in the closed position, prevents movement of the gate relative to the frame, and wherein said stop member is driven in timed relation relative to movement of said gate such that upon rotation of said operating shaft to move said gate to the open position said stop member is automatically displaced from the plane of travel of the gate prior to movement of the gate. .Iaddend..Iadd.28. The gate control apparatus and railway hopper car discharge gate assembly according to claim 27 wherein said operating shaft is coupled to said gate through a rack and pinion drive mechanism arranged beneath the predetermined plane of travel of said gate. .Iaddend..Iadd.29. The gate control apparatus and railway hopper car discharge gate assembly according to claim 28 where a lost motion mechanism is provided between said operating shaft and said rack and pinion drive mechanism for permitting rotation of said operating shaft through a predetermined range of rotation prior to imparting an opening movement to said gate. .Iaddend..Iadd.30. The gate control apparatus and railway hopper car discharge gate assembly according to claim 27 wherein said stop member is mounted for generally vertical movement. .Iaddend..Iadd.31. The gate control apparatus and railway hopper car discharge gate assembly according to claim 27 wherein said lock assembly further includes a spring for resiliently urging said stop member into a position to prevent movement of said gate. .Iaddend..Iadd.32. The gate control apparatus and railway hopper car discharge gate assembly according to claim 27 further including an actuator rotatable with and in response to rotation of said operating shaft for effecting automatic displacement of the stop member prior to movement of the gate. .Iaddend..Iadd.33. A gate control apparatus and railway car discharge gate assembly including a frame defining a generally rectangular discharge opening with a generally rectangular discharge gate mounted on said frame for movement along a predetermined path of travel extending between a closed position and an open position, said apparatus comprising:   an operator controlled actuation assembly for moving said gate along its predetermined path of travel between the open and closed positions, said actuation assembly including an operating shaft mounted on said frame for rotation about a fixed axis extending generally parallel to an edge of said gate and wherein said operating shaft is operably coupled to said gate;   a lock assembly including a stop member which, when said gate is in its closed position, is positioned to prevent movement of the gate relative to the frame and which is displacable to a released position to permit said gate to move relative to said frame toward the open position;   and wherein a drive including a lost motion mechanism is arranged between said operating shaft and said stop member for automatically effecting, in sequential order and in response to rotation of said operating shaft, displacement of said stop member and movement of said gate. .Iaddend..Iadd.34. The gate control apparatus and railway hopper car discharge gate assembly according to claim 33 wherein said actuation assembly further includes a rack and pinion drive assembly comprised of a pair of laterally spaced pinion gears mounted on said operating shaft for engagement with a pair of laterally spaced racks operably to an undersurface of said gate. .Iaddend..Iadd.35. The gate control apparatus and railway hopper car discharge gate assembly according to claim 33 wherein said stop member of said lock assembly includes a lever pivotally mounted for rocking movement about an axis extending generally parallel to said operating shaft. .Iaddend..Iadd.36. The gate control apparatus and railway hopper car discharge gate assembly according to claim 35 wherein said lock assembly further includes a spring for resiliently urging said lever into a position to prevent movement of said gate.   
     
     
        .Iaddend..Iadd.     The gate control apparatus and railway hopper car discharge gate assembly according to claim 33 wherein said drive further includes a cam mounted on and for rotation with said operating shaft for engaging said lever in a manner positively displacing the lever to a released position in response to rotation of said operating shaft. .Iaddend..Iadd.38. The gate control apparatus and railway hopper car discharge gate assembly according to claim 33 wherein said operating shaft is operably coupled to said gate through a rack and pinion assembly, and wherein said lost motion mechanism includes a specifically configured slot defined by pinions of said rack and pinion assembly for allowing said operating shaft to rotate through a predetermined angle of rotation prior to imparting motion to said pinions and thereby movement of the gate. .Iaddend..Iadd.39. The gate control apparatus and railway hopper car discharge gate assembly according to claim 38 wherein said lost motion mechanism incorporates a dwell period during which a cam member carried on the operating shaft is rotated into engagement with the stop member and an actuating period during which the cam member is rotated to positively move the stop member to a released position prior to movement of the gate. .Iaddend..Iadd.40. A gate control apparatus and railway hopper car discharge gate assembly including a frame defining a generally rectangular discharge opening with a generally rectangular discharge gate mounted on said frame for movement between open and closed positions along a predetermined path of travel, said apparatus comprising: an operating shaft assembly rotatably supported on said frame adjacent an end of said opening, said operating shaft assembly being connected to said gate whereby said gate slidably moves between the open and closed positions in response to rotation of said operating shaft assembly, said operating shaft assembly including capstans at opposite ends of a shaft;   a lock assembly carried on said frame and including a displacable stop member which, when said gate is in the closed position, extends into the predetermined path of travel to positively engage an edge of said rate thereby preventing movement of the gate relative to said frame; and   wherein a drive is provided between said lock assembly stop member and said operating shaft assembly for positively displacing said stop member from said path of travel of said gate upon rotation of one of said capstans of said operating shaft assembly prior to movement of the gate toward the   
     
     
        open position. .Iaddend..Iadd.41.  The gate control apparatus and railway hopper car discharge gate assembly according to claim 40 wherein said operating shaft assembly is connected to said gate through pinion gears arranged upon said operating shaft assembly and which intermesh with racks fitted to an underside of said gate. .Iaddend..Iadd.42. The gate control apparatus and railway hopper car discharge gate assembly according to claim 40 wherein said stop member is pivotally mounted on said frame for vertical movement about a fixed generally horizontal axis extending 
     
     
        generally parallel to said operating shaft assembly. .Iaddend..Iadd.43. The gate control apparatus and railway hopper car discharge gate assembly according to claim 40 wherein said drive includes a cam mounted on said operating shaft assembly for positively displacing said stop member from the path of travel of said gate upon rotation of a portion of said operating shaft assembly. .Iaddend..Iadd.44. The gate control apparatus and railway hopper car discharge gate assembly according to claim 40 wherein said stop member is resiliently urged by a spring toward an engaging position with said gate. .Iaddend..Iadd.45. The gate control apparatus and railway hopper car discharge gate assembly according to claim 40 wherein said drive includes a lost motion mechanism for permitting a predetermined range of free rotation of one of said capstans of the operating shaft assembly prior to movement of said gate toward the open position. .Iaddend..Iadd.46. A gate control apparatus and railway hopper car discharge gate assembly including a frame defining a discharge opening with a discharge gate slidably arranged on said frame for movement along a predetermined plane of travel between open and closed positions, said apparatus comprising: an operating shaft assembly supported for rotation by said frame and operable to selectively move the gate between the open and closed positions in response to rotation of said operating shaft assembly, said operating shaft assembly including capstans at opposite ends of a shaft; and   a lock assembly carried on said frame and operably coupled to said operating shaft assembly, said lock assembly including a stop member which, when the gate is in its closed position, extends into said plane of travel to prevent movement of the gate relative to the frame, and wherein said stop member is driven in timed relation relative to movement of said crate such that upon rotation of one of said capstans of said operating shaft assembly to move said rate to the open position said stop member is automatically removed from the plane of travel of the gate prior to movement of the sate toward the open position. .Iaddend..Iadd.47. The gate control apparatus and railway hopper car discharge gate assembly according to claim 46 wherein said operating shaft assembly is coupled to said gate through a rack and pinion drive mechanism arranged beneath the predetermined plane of travel of said gate. .Iaddend..Iadd.48. The gate control apparatus and railway hopper car discharge gate assembly according to claim 47 where a lost motion mechanism is provided between said operating shaft assembly and said rack and pinion drive mechanism for permitting rotation of one of said capstans of said operating shaft assembly through a predetermined range of rotation prior to imparting an opening movement to said gate. .Iaddend..Iadd.49. The gate control apparatus and railway hopper car discharge gate assembly according to claim 46 wherein said stop member is mounted on said frame for generally vertical movement relative to the plane of travel of said gate. .Iaddend..Iadd.50. The gate control apparatus and railway hopper car discharge gate assembly according to claim 46 wherein said stop member of said locking assembly is biased into the plane of travel of said gate. .Iaddend..Iadd.51. The gate control apparatus and railway hopper car discharge gate assembly according to claim 46 further including an actuator rotatable with and in response to rotation of a portion of said operating shaft assembly for positively removing said stop member from the plane of travel of the gate. .Iaddend..Iadd.52. A gate control apparatus and railway hopper discharge gate assembly including a frame defining a generally rectangular discharge opening with a generally rectangular discharge gate mounted on said frame for movement along a predetermined path of travel extending between a closed position and an open position, said apparatus comprising:   an operator controlled actuation assembly for moving said gate along its predetermined path of travel between the open and closed positions, said actuation assembly including an operating shaft and capstans connected to opposite ends of the operating shaft for rotation about a fixed axis extending generally parallel to an edge of said gate and wherein said actuation assembly is operably coupled to said gate;   a lock assembly carried on said frame, said lock assembly including a stop member which, when said gate is in the closed position, is positioned to wedge against an edge of the gate thereby preventing movement of the gate relative to the frame and which is displacable to a released position to permit said gate to move relative to said frame toward the open position;   and wherein a drive including a lost motion mechanism is arranged between said actuation assembly and said stop member for automatically effecting, in sequential order and in response to rotation of one of said capstans of said actuation assembly, displacement of said stop member from the path of travel of said gate and movement of said gate toward the open position. .Iaddend..Iadd.53. The gate control apparatus and railway hopper car discharge gate assembly according to claim 52 wherein said actuation assembly further includes a rack and pinion drive assembly comprised of a pair of laterally spaced pinion gears mounted on said operating shaft for engagement with a pair of laterally spaced racks operably fixed to an undersurface of said gate. .Iaddend..Iadd.54. The gate control apparatus and railway hopper car discharge gate assembly according to claim 52 wherein said stop member of said lock assembly includes a lever pivotally mounted on the frame for rocking movement about an axis extending generally parallel to said operating shaft, with one end of said lever being adapted to positively engage and wedge against said gate edge. .Iaddend..Iadd.55. The gate control apparatus and railway hopper car discharge gate assembly according to claim 54 wherein said lock assembly further includes a spring member for resiliently urging said lever into engagement with said gate. .Iaddend..Iadd.56. The gate control apparatus and railway hopper car discharge gate assembly according to claim 54 wherein said drive further includes a cam mounted on and for rotation with said operating shaft for engaging said lever in a manner positively displacing the lever to a released position in response to rotation of a portion of said actuation assembly. .Iaddend..Iadd.57. The gate control apparatus and railway hopper car discharge gate assembly according to claim 52 wherein said operating shaft is operably coupled to said gate through a rack and pinion assembly, and wherein said lost motion mechanism includes a specifically configured slot defined by pinions of said rack and pinion assembly for allowing one of said capstans of said actuation assembly to rotate through a predetermined angle of rotation prior to imparting motion to said pinions and thereby movement of the gate. .Iaddend..Iadd.58. The gate control apparatus and railway hopper car discharge gate assembly according to claim 57 wherein said lost motion mechanism incorporates a dwell period during which a cam member carried on the operating shaft is rotated into engagement with the stop member and an actuating period during which the cam member is rotated to positively move the stop member to a released position prior to movement of the gate   
     
     
        toward the open position. .Iaddend..Iadd.59.  A gate control apparatus and railway hopper car discharge gate assembly including a frame defining a generally rectangular discharge opening with a generally rectangular discharge gate mounted on said frame for movement between open and closed positions along a predetermined path of travel, said apparatus comprising: an operating shaft assembly rotatably supported on said frame adjacent an end of said opening, said operating shaft assembly being connected to said gate whereby said gate slidably moves between the open and closed positions in response to rotation of said operating shaft assembly, said operating shaft assembly including capstans at opposite ends of a shaft;   a lock assembly including a displacable stop member which, when said gate is in its closed position, prevents movement of the gate relative to said frame; and   wherein a drive is provided between said lock assembly stop member and said operating shaft assembly for positively displacing said stop member prior to movement of the gate. .Iaddend..Iadd.60. The gate control apparatus and railway hopper car discharge gate assembly according to claim 59 wherein said operating shaft assembly is connected to said gate through pinion gears arranged upon said operating shaft assembly and which intermesh with racks fitted to an underside of said gate. .Iaddend..Iadd.61. The gate control apparatus and railway hopper car discharge gate assembly according to claim 59 wherein said stop member is pivotally mounted for vertical movement about a fixed generally horizontal axis extending generally parallel to said operating shaft assembly. .Iaddend..Iadd.62. The gate control apparatus and railway hopper car discharge gate assembly according to claim 59 wherein said drive includes a cam mounted on said operating shaft assembly for positively displacing said stop member upon rotation of said operating shaft assembly. .Iaddend..Iadd.63. The gate control apparatus and railway hopper car discharge gate assembly according to claim 59 wherein said lock assembly further comprises a spring for resiliently urging said stop member into a position to prevent movement of said gate. .Iaddend..Iadd.64. The gate control apparatus and railway hopper car discharge gate assembly according to claim 59 wherein said drive includes a lost motion mechanism for permitting a predetermined range of free rotation of one of said capstans of the operating shaft assembly prior to movement of said gate. .Iaddend..Iadd.65. A gate control apparatus and railway hopper car discharge gate assembly including a frame defining a discharge opening with a discharge gate slidably arranged on said frame for movement along a predetermined plane of travel between open and closed positions, said apparatus comprising:   an operating shaft assembly supported for rotation by said frame and operable to selectively move the gate between the open and closed positions in response to rotation of said operating shaft assembly, said operating shaft assembly including capstans at opposite ends of a shaft; and   a lock assembly operably coupled to said operating shaft assembly, said lock assembly including a stop member which, when the gate is in the closed position, prevents movement of the gate relative to the frame, and wherein said stop member is driven in timed relation relative to movement of said gate such that upon rotation of one of said capstans of said operating shaft assembly to move said gate to the open position said stop member is automatically displaced from the plane of travel of the gate prior to movement of the gate. .Iaddend..Iadd.66. The gate control apparatus and railway hopper car discharge gate assembly according to claim 65 wherein said operating shaft assembly is coupled to said gate through a rack and pinion drive mechanism arranged beneath the predetermined plane of travel of said gate. .Iaddend..Iadd.67. The gate control apparatus and railway hopper car discharge gate assembly according to claim 66 wherein a lost motion mechanism is provided between said operating shaft assembly and said rack and pinion drive mechanism for permitting rotation of one of said capstans of said operating shaft assembly through a predetermined range of rotation prior to imparting an opening movement to said gate. .Iaddend..Iadd.68. The gate control apparatus and railway hopper car discharge gate assembly according to claim 65 wherein said stop member is mounted for generally vertical movement. .Iaddend..Iadd.69. The gate control apparatus and railway hopper car discharge gate assembly according to claim 65 wherein said lock assembly further includes a spring for resiliently urging said stop member into a position to prevent movement of said gate. .Iaddend..Iadd.70. The gate control apparatus and railway hopper car discharge gate assembly according to claim 65 further including an actuator rotatable with and in response to rotation of said operating shaft assembly for effecting automatic displacement of the stop member prior to movement of the gate. .Iaddend..Iadd.71. A gate control apparatus and railway hopper car discharge gate assembly including a frame defining a generally rectangular discharge opening with a generally rectangular discharge gate mounted on said frame for movement along a predetermined path of travel extending between a closed position and an open position, said apparatus comprising:   an operator controlled actuation assembly for moving said gate along its predetermined path of travel between the open and closed positions, said actuation assembly including an operating shaft and capstans connected to opposite ends of the operating shaft for rotation about a fixed axis extending generally parallel to an edge of said gate and wherein said actuation assembly is operably coupled to said gate;   a lock assembly including a stop member which, when said gate is in its closed position, is positioned to prevent movement of the gate relative to the frame and which is displacable to a released position to permit said gate to move relative to said frame toward the open position;   and wherein a drive including a lost motion mechanism is arranged between said actuation assembly and said stop member for automatically effecting, in sequential order and in response to rotation of one of said capstans of said actuation assembly, displacement of said stop member and movement of said gate. .Iaddend..Iadd.72. The gate control apparatus and railway hopper car discharge gate assembly according to claim 71 wherein said actuation assembly further includes a rack and pinion drive assembly comprised of a pair of laterally spaced pinion gears mounted on said operating shaft for engagement with a pair of laterally spaced racks operably fixed to an undersurface of said gate. .Iaddend..Iadd.73. The gate control apparatus and railway hopper car discharge gate assembly according to claim 71 wherein said stop member of said lock assembly includes a lever pivotally mounted for rocking movement about an axis extending generally parallel to said operating shaft. .Iaddend..Iadd.74. The gate control apparatus and railway hopper car discharge gate assembly according to claim 73 wherein said lock assembly further includes a spring for resiliently urging said lever into a position to prevent movement of said gate. .Iaddend..Iadd.75. The gate control apparatus and railway hopper car discharge gate assembly according to claim 73 wherein said drive further includes a cam mounted on and for rotation with said operating shaft for engaging said lever in a manner positively displacing the lever to a released position in response to rotation of said actuation assembly. .Iaddend..Iadd.76. The gate control apparatus and railway hopper car discharge gate assembly according to claim 71 wherein said operating shaft is operably coupled to said gate through a rack and pinion assembly, and wherein said lost motion mechanism includes a specifically configured slot defined by pinions of said rack and pinion assembly for allowing one of said capstans of said actuation assembly to rotate through a predetermined angle of rotation prior to imparting motion to said pinions and thereby movement of the gate. .Iaddend..Iadd.77. The gate control apparatus and railway hopper car discharge gate assembly according to claim 76 wherein said lost motion mechanism incorporates a dwell period during which a cam member carried on the operating shaft is rotated into engagement with the stop member and an actuating period during which the cam member is rotated to positively move the stop member to a released position prior to movement of the gate. .Iaddend.