Railway hydraulic cushioning device

Claim 1

IN A HYDRAULIC CUSHION DEVICE COMPRISING A FLUIDFILLED CYLINDER, A FIRST BASE PLATE FIXED TO ONE END OF SAID CYLINDER, AN INTERMEDIATE CYLINDER HEAD FIXED WITHIN THE BORE OF SAID CYLINDER INWARDLY OF THE OPEN END THEREOF, FLUID DISPLACEMENT MEANS INCLUDING A PISTON HEAD RECIPROCABLE WITHIN SAID CYLINDER BORE FOR MOVEMENT BETWEEN SAID BASE PLATE AND SAID INTERMEDIATE CYLINDER HEAD TO AND FROM AN EXTENDED POSITION AND A CONTRACTED POSITION, A TUBULAR PISTON ROD FIXED AT ONE END TO SAID PISTON HEAD AND EXTENDING THROUGH SAID INTERMEDIATE CYLINDER HEAD OUTWARDLY OF SAID OPEN END OF SAID CYLINDER, A FLEXIBLE BOOT FIXED BETWEEN SAID INTERMEDIATE CYLINDER HEAD AND SAID OUTWARDLY EXTENDING END OF SAID TUBULAR PISTON ROD, HYDRAULIC FLUID PASSAGE MEANS THROUGH SAID INTERMEDIATE CYLINDER HEAD PROVIDING HYDRAULIC FLUID COMMUNICATION BETWEEN SAID CYLINDER BORE AND SAID FLEXIBLE BOOT, A SECOND BASE PLATE FIXED TO SAID OUTWARDLY EXTENDING END OF SAID TUBULAR PISTON ROD, RETURN SPRING MEANS INTERPOSED BETWEEN SAID FIRST AND SECOND BASE PLATES, AN AXIAL ORIFICE THROUGH SAID PISTON HEAD PROVIDING HYDRAULIC FLUID COMMUNICATION WITH SAID BORE, PORT MEANS IN SAID TUBULAR PISTON ROD PROVIDING HYDRAULIC FLUID COMMNICATION BETWEEN THE PISTON ROD BORE AND SAID CYLINDER BORE, THE IMPROVEMENT COMPRISING A METERING PIN FORMED FROM A FORGING INCLUDING A METERING LENGTH OF SUBSTANTIALLY CONSTANT DIAMETER ALONG THE LENGTH THEREOF AND SLIDABLE WITHIN SAID ORIFICE, LENGTHWISE EXTENDING FLUTE MEANS OF VARYING DEPTH FORMED ALONG THE LENGTH OF SAID METERING LENGTH FOR VARYING THE EFFECTIVE ORIFICE AREA OF SAID PISTON HEAD ORIFICE SO AS TO IMPART A SUBSTANTIALLY CONSTANT FORCE TRAVEL CHARACTERISTIC TO SAID CUSHION DEVICE DURING CONTRACTION THEREOF, AN ANNULAR FLANGE INTEGRALLY FORMED ON ONE END OF SAID METERING PIN, AN OPENING IN SAID BASE PLATE SNUGLY RECEIVING SAID METERING PIN, A CIRCULAR RECESS COAXIAL WITH SAID OPENING ON THE OUTER FACE OF SAID BASE PLATE AND HAVING A SUBSTANTIALLY FLAT BOTTOM WALL FOR ACCOMMODATING SAID ANNULAR FLANGE THEREON, SAID ANNULAR FLANGE EXTENDING RADIALLY BEYOND SAID BASE PLATE OPENING AND SPACED INWARDLY FROM THE PERIPHERY OF SAID CIRCULAR RECESS, A SEALING GASKET DISPOSED ABOUT SAID OPENING AND BETWEEN THE BOTTOM WALL OF SAID CIRCULAR RECESS AND UNDERSIDE OF SAID ANNULAR FLANGE, AND FASTENING MEANS EXTENDING THROUGH SAID ANNULAR FLANGE AND FASTENED TO SAID BASE PLATE FOR SECURING SAID METERING PIN TO SAID BASE PLATE.