Self-steering railway bogie

Abstract

The invention relates to railway bogies, and more particularly, but not exclusively to a self-steering bogie for a locomotive. In accordance with the invention there is provided a self-steering railway bogie ( 1 ) comprising leading and trailing wheelset ( 2.4 ) having two ends ( 3,5 ) and a frame for limiting the movement of the wheelset ends. The bogie is provided with a number of fluid cylinders ( 7 ) attached between the wheelset ends and the frame, and fluid flow means ( 8 ) between the cylinders allowing wheelsets to yaw inversely relative to each other and restricting other relative movement of the wheelsets.

1 . A self-steering railway bogie comprising:
 a leading wheelset having two ends;   a trailing wheelset having two ends;   a frame for limiting the movement of the wheelset ends;   a number of fluid cylinders attached between the wheelset ends and the frame; and   fluid flow means between the cylinders allowing wheelsets to yaw inversely relative to each other and restricting other relative movement of the wheelsets,   wherein the hydraulic cylinders are double-acting cylinders having operatively front and rear chambers, the operatively front chambers of the hydraulic cylinders attached between the frame and the leading wheelset ends are hydraulically connected, the operatively front chambers of the hydraulic cylinders attached between the frame and the trailing wheelset ends are hydraulically connected, the operatively rear chambers of the cylinders on a side are hydraulically connected, and the operatively rear chambers of the cylinders on an opposing side are connected.   
     
     
         2 . The self-steering railway bogie of  claim 1  wherein the hydraulic cylinders have a piston between the front and rear chambers. 
     
     
         3 . The self-steering railway bogie of  claim 2  wherein each chamber has hydraulic connection for connecting a hydraulic line which forms part of the fluid flow means. 
     
     
         4 . The self-steering railway bogie of  claim 3  wherein the fluid flow means allows the cylinders to move such that diagonally opposing cylinders correspond to each other. 
     
     
         5 . The self-steering railway bogie of  claim 3  wherein the cylinders are attached in a horizontal plane at axle center height. 
     
     
         6 . The self-steering railway bogie of  claim 3  wherein the hydraulic cylinders and fluid flow means are retrofitted to an existing bogie. 
     
     
         7 . A method of retro fitting a bogie, having a leading and trailing wheelset, with a hydraulic steering system comprising the steps of:
 replacing rigid axle box links with hydraulic cylinders of corresponding size; and   providing the hydraulic cylinders with fluid flow means between the cylinders for allowing wheelsets to yaw inversely relative to each other and restricting other relative movement of the wheelsets, wherein the cylinders are attached longitudinally.   
     
     
         8 . A method of retro fitting a bogie, having a leading and trailing wheelset, with a hydraulic steering system comprising the steps of:
 replacing rigid axle box links with hydraulic cylinders of corresponding size; and   providing the hydraulic cylinders with fluid flow means between the cylinders for allowing wheelsets to yaw inversely relative to each other and restricting other relative movement of the wheelsets, wherein the cylinders are attached diagonally.   
     
     
         9 . The method of  claim 8  wherein the cylinders are mounted diagonally so that imaginary axes through opposing leading and trailing cylinders intersect at the center of a bogie. 
     
     
         10 - 11 . (canceled) 
     
     
         12 . The self-steering railway bogie of  claim 2  wherein the fluid flow means allows the cylinders to move such that diagonally opposing cylinders correspond to each other. 
     
     
         13 . The self-steering railway bogie of  claim 12  wherein the cylinders are attached in a horizontal plane at axle center height. 
     
     
         14 . The self-steering railway bogie of  claim 13  wherein the hydraulic cylinders and fluid flow means are retrofitted to an existing an existing bogie. 
     
     
         15 . The self-steering railway bogie of  claim 12  wherein the hydraulic cylinders and fluid flow means are retrofitted to an existing an existing bogie. 
     
     
         16 . The self-steering railway bogie of  claim 1  wherein the fluid flow means allows the cylinders to move such that diagonally opposing cylinders correspond to each other. 
     
     
         17 . The self-steering railway bogie of  claim 16  wherein the cylinders are attached in a horizontal plane at axle center height. 
     
     
         18 . The self-steering railway bogie of  claim 17  wherein the hydraulic cylinders and fluid flow means are retrofitted to an existing an existing bogie. 
     
     
         19 . The self-steering railway bogie of  claim 16  wherein the hydraulic cylinders and fluid flow means are retrofitted to an existing an existing bogie. 
     
     
         20 . The self-steering railway bogie of  claim 1  wherein the cylinders are attached in a horizontal plane at axle center height. 
     
     
         21 . The self-steering railway bogie of  claim 1  wherein the hydraulic cylinders and fluid flow means are retrofitted to an existing an existing bogie.