Patent GB-1288204-A (GB)
IPC: B61F5/14
Filed: 1970-01-13
Abstract: 1288204 Axle trucks; cars continuous forming trains DOMINION FOUNDRIES & STEEL Ltd 13 Jan 1970 [13 Jan 1969] 1676/70 Heading B7L A bolster in a two-axle railway truck having side frame members 10, 11 and transom members 12, 13 extending between the members 10, 11 comprises lower and upper bolster members 22, 23 respectively, the bolster 22 being supported upon the side frames 10, 11 by four resilient suspension units 24 which receive spigots 25 on the bolster 22 and the depressed centre portion of the bolster 22 has a downwardly extending spigot 26 which pivots in an aperture 27 in a pivot member 28, while each end of the upper bolster 23 is connected to the adjacent end member 34 of the lower bolster 22 by a pivoted linkage which comprises a pair of spaced parallel links 40 pivoted at their adjacent ends by a rod 41 to the member 34 and at their other ends by a rod 39 to one crank arm of a generally Y-shaped bell crank lever 37, the other crank arms of the lever 37 being connected by pivot rods 42 to the respective ends of a connecting link 43 which extends through apertures 44 in the bolster 22. The pivoted linkage is completed by a depending link 45 fixed rigidly at its upper end to a central member 35 of the bolster 23 and pivoted by a rod 46 at its lower end to one end of a transverse link 47 whose other end is pivoted by a rod 48 to the link 43. Lateral arcuate tilting motion of the bolster members 22, 23 relative to one another about a longitudinal axis is controlled by a mechanism operating motor units 32 connected to the pivot 28 via respective suspension members 30 and which comprise two double acting hydraulic units 50 disposed one on each side of the composite bolster while the floor 20 of the car body is mounted upon the bolster 23 by laterally spaced air springs 36 with their compression axes vertical. Each unit 50 comprises a cylindrical member 51 pivoted at 52 to the bolster 22 and a piston member 53 pivoted at 54 to the bolster 23. Diagonally extending links 55 (Fig. 1) are connected by spherical rubber bushings to the bolster 22 and to brackets 56 fastened approximately at the centre of the car floor and laterally extending links 57 are connected by similar bushings to the bolster 23 and brackets 21 of the car floor. The tilt axis 58 remains approximately stationary in the position illustrated (Fig. 4) during tilting motion of the bolster. A control system for operation of the motor units 50 of an entire train as described with reference to Fig. 6. A gyroscopic or inertial device 77 is mounted on the forward truck of a locomotive 74 and detects the rate of deviation of the truck frame from the horizontal. A second gyroscopic or inertial device 78 is mounted on the body of the locomotive 74 and determines the rate of change of direction thereof from a straight line path. The outputs of these two devices, together with that of a speedometer 79 are fed to a control device 73 which produces an output corresponding to the amount of lean or tilting required for the car body to ensure that the lateral forces on passengers are below a desired level. This output is fed to a servo 72 which produces the required operation of the motor units 50. In an embodiment described with reference to Fig. 7, the pivoted linkage 37 to 45 mounts the lower bolster 22 to the truck frame, each of the pivot rods 38 being mounted in a respective pair of parallel transverse projections 86 upstanding from the truck frame. In this embodiment, the four suspension units 24 and the pivot member 28 engaging the units 29 permits pivoting movement of the truck relative to the car body. Additional damping units 88 are connected between the upper bolster member 23 and the car floor. A tilting control system which is particularly applicable to the embodiment of Figs. 4 and 7 employs an accelerometer 90 mounted by a bracket 89 on the bolster 23 and located on the longitudinal central vertical plane of the car. The accelerometer 90 output is fed to a nullseeking circuit corresponding to the device 74 which controls the motor units 50 so as to produce a minimum in the accelerometer output.