GB1205071A - Improvements in or relating to railway bogies - Google Patents

Abstract

1,205,071. Railway vehicle undercarriages. GLOUCESTER RAILWAY CARRIAGE & WAGON CO. Ltd. 19 April, 1968 [15 April, 1967], No. 17387/67. Heading B7L. A railway bogie comprises sideframes 1, Fig. 1, each provided with two spaced hollow guide columns 5 defining therebetween a bolster guide within which the corresponding end 6 of a bolster 4 is slidable vertically during normal movement on suspension springs 7, wherein at least one column 5 houses and supports therein damping means 13, 25, Figs. 2 and 3 through the intermediary of a damping control member 36 which follows vertical movement of the bolster 4 whereby a greater damping force is applied to the bolster when loaded than that applied when the bolster is unloaded (tare condition). The damping means comprises a friction shoe 13, having a facing 14 engaging a side face 15 of the bolster end 6 and a spring 25. The latter urges upper and lower collets 16, 17 between upper and lower guides 12, 19 of the column 5 and against the shoe 13. The inner end of the spring 25 engages a plate 30 abutting the collets and the outer end engages a plate 33 in abutment with a vertical arm 43 of a bellcrank 36 pivoted to the column 5 at 37 and whose horizontal arm 38 has a convex surface 48 to engage a pad 40 on the bottom of the bolster. The collets 16, 17 have planar surfaces 26, 27 engaging convex surfaces 23, 24 of the shoe 13, which is therefore self-centring. In another embodiment Figs. 5 and 6 (not shown) the outer end of the spring 25 abuts a yoke pivoted to two levers pivoted at their upper ends to the opposite sides of the column (5). The levers, at their lower ends, have rollers engaging a cam surface depending from the bolster 4. The cam surface has upper and lower vertical surfaces joined by a curved surface whereby a constant damping force is provided for a light load range and a constant but increased force is applied over a more heavily loaded range. Other embodiments employing cam levers pivoted at their lower ends to the column 5 and operating through a lever or yoke are described with reference to Figs. 7 to 10 (not shown). The cams may be arranged to provide an increasing damping force during upward movement of the bolster during vibration of the latter with the guides and a decreasing damping force during downward movement during such vibration.