Patent ID: 8356560

Claim:
A railroad hopper car comprising: a body for carrying lading in the form of particulate matter, said body being mounted upon railroad car trucks for rolling motion along railroad tracks in a longitudinal direction, and having draft sills at either end thereof to permit said railroad hopper car to be connected to other railroad car bodies; said body including a hopper having a discharge through which the lading may be disgorged under the influence of gravity; said discharge being governed by a door mechanism, said door mechanism including a door panel movable from a first position to a second position, said first position defining a closed position of said discharge in which said door panel obstructs exit of the lading, said second position defining an open position of said discharge; said door panel is movably connected to said car body by at least a first linkage member and a second linkage member, said first linkage member being pivotally connected to said body and pivotally connected to said door panel; said second linkage member being pivotally connected to said body and to said door panel; and said car body, said linkage members and said door panel defining a four bar linkage, said door panel has a proximal portion and a distal portion, said first linkage member is pivotally connected to said door panel at a connection that is closer to said proximal portion than to said distal portion, said second linkage member is connected to said door panel closer to said distal portion than is said first linkage member, and one of (a) said first linkage member is connected to said body of said railroad hopper car at a first pivotal connection, and said proximal portion of said door panel moves from a position lower than said first pivotal connection to a position higher than said first pivotal connection during motion of said door panel from said closed position to said open position; and (b) said proximal portion of said door panel has an overall dz/dx when said door panel moves between said first position and said second position that is greater than one.