Hopper wagons

Claim 1

A HOPPER WAGON COMPRISING A CHASSIS AND HAVING AN ARRANGEMENT FOR THE AUTOMATIC CONTROL OF THE OPENING AND CLOSING OF THE HOPPERS OF THE WAGON WHEREIN TE WAGON IS FITTED WITH ONE OR MORE SETS OF AT LEAST TWO SHUT-OFF SYSTEMS, EACH SHUT-OFF SYSTEM COMPRISING A PIVOTALLY MOUNTED MASTER TRAP-DOOR AND A PIVOTALLY MOUNTED SUPPORTED TRAPDOOR, THE EDGE OF THE SUPPORTED TRAP-DOOR BEING COVERED BY THAT OF THE MASTER TRAP-DOOR IN THE COLSED POSITION IN SUCH A WAY THAT THE MASTER TRAP-DOOR HOLDS THE SUPPORTED TRAP-DOOR CLOSED, ARTICULATED RODS BEING PROVIDED WHICH CONNECT TOGETHER THROUGH LEVER-ARMS FIXED ON SAID TRAPDOORS ON THE ONE HAND THE GROUP OF MASTER TRAP-DOORS AND CONNECT TOGETHER ON THE OTHER HAND THE GROUP OF SUPPORTED TRAP-DOORS IN SUCH A WAY THAT THE TRAP-DOORS IN EACH OF THE GROUPS PIVOT AS A WHOLE, EACH SET OF SHUT-OFF SYSTEMS COMPRISING TWO RETURN MEMBERS, EACH RETURN MEMBER PULLING SEPARATELY AND PERMANENTLY IN THE DIRECTION OF CLOSING OF GROUPS OF TRAP-DOORS ONE OF SAID SUPPORTED TRAP-DOORS BEING EQUIPPED WITH ONE OF TWO HOOKING ELEMENTS OF A FIRST LOCKING SYSTEM COMPRISING A LATCH AND A HOLDING MEMBER ARRANGED IN SUCH A WAY THAT SAID LATCH ENGAGES AUTOMATICALLY SAID HOLDING MEMBER WHEN THE TRAP-DOORS REACH THE OPEN POSITION, AT LEAST THE SUPPORTED TRAP-DOORS BEING THUS HELD IN SAID POSITION, AND THAT SAID TWO HOOKING ELEMENTS BE SEPARATED FROM EACH OTHER UNDER THE ACTION OF A CAM OR RAMP FIXED TO THE GROUND AND ARRANGED IN THE PATH OF A FEELER FIXED TO SAID LATCH, SAID MASTER TRAP-DOOR BEING EQUIPPED WITH ONE OF TWO HOOKING ELEMENTS OF A SECOND LOCKING SYSTEM COMPRISING A HOOK AND A HOLDING PIECE, THE OTHER HOOKING ELEMENT BEING CONNECTED TO THE CHASSIS OF THE WAGON IN SUCH A WAY THAT SAID HOOK ENGAGES AUTOMATICALLY SAID HOLDING PIECE WHEN THE TRAP-DOORS REACH THE OPEN POSITION, SAID SECOND LOCKING SYSTEM FURTHER BEING CONTROLLED IN SUCH A WAY BY A SUPPORTED TRAPDOOR THAT SAID SUPPORTED TRAP-DOOR UNBOLTS SAID SECOND LOCKING SYSTEM ONLY AFTER HAVING REACHED A POSITION NEAR THE COLSED POSITION DURING ITS CLOSING MOVEMENT