Spring loaded door construction for railroad hopper car

Claim 1

A SPRING LOADED DOOR CLOSING DEVICE FOR RAILROAD HOPPER CARS AND THE LIKE WHEREIN THE HOPPER DOOR IS HINGEDLY CONNECTED TO THE HOPPER CAR ALONG A HINGE LINE Z AND IS MOVABLE DOWNWARDLY FROM A CLOSED TO AN OPEN POSITION, SAID DEVICE COMPRISING A FIRST MOUNTING MEMBER PIVOTALLY CONNECTED TO THE OUTER SIDE OF THE HOPPER DOOR AT A PIVOT LINE X REMOTE FROM THE HINGE LINE Z OF SAID HOPPER DOOR, A SHAFT SECURED AT ONE END TO SAID FIRST MOUNTING MEMBER AND PROJECTING OUTWARDLY THEREFROM, A SECOND MOUNTING MEMBER CONFIGURED TO SLIDABLY RECEIVE THE OPPOSITE END OF SAID SHAFT, SAID SECOND MOUNTING MEMBER BEING PIVOTALLY CONNECTED AT A PIVOT LINE Y TO A FIXED SUPPORT LYING BENEATH AND IN SPACED RELATION TO THE HINGE LINE Z OF SAID HOPPER DOOR, A HELICAL SPRING SURROUNDING SAID SHAFT AND EXTENDING BETWEEN SAID FIRST AND SECOND MOUNTING MEMBERS, THE LOCATION OF SAID PIVOT LINE Y BEING SO CHOSEN THAT: (A) WHEN SAID HOPPER DOOR IS IN THE CLOSED POSITION THE LONGITUDINAL AXIS OF THE CLOSING DEVICE, AS DEFINED BY A STRAIGHT LINE XY EXTENDING BETWEEN THE PIVOT LINES X AND Y, IS ANGULARLY RELATED TO A PLANE ZX PASSING THROUGH THE HINGE LINE Z AND PIVOT LINE X, AND (B) WHEN SAID DOOR IS MOVED TO THE OPEN POSITION THE PIVOT LINE X IS MOVED TOWARD PIVOT LINE Y AND THE HELICAL SPRING IS COMPRESSED TO SLIGHTLY LESS THAN FULLY SOLID CONDITION, AND THE LONGITUDINAL AXIS OF THE CLOSING DEVICE, AS DEFINED BY THE STAIGHT LINE XY, LIES IN NEAR PARALLELISM TO THE PLANE ZX, AND STOP MEANS OPERATIVE TO ESTABLISH THE OPEN POSITION AND SAID HOPPER DOOR AND PREVENT THE DOOR FROM SWINGING BEYOND THE SAID OPEN POSITION, WHEREBY THE OPENING MOVEMENT OF THE DOOR IS CUSHIONED BY THE HELICAL SPRING AS IT IS COMPRESSED AND YET THE DOOR IS POSITIVELY STOPPED BEFORE THE CLOSING DEVICE REACHES THE DEAD-CENTER POSITION IN WHICH ITS LONGITUDINAL AXIS PARALLELS THE PLANE ZX.