MECHANISM FOR CONNECTING A BUSH FOR RAILWAY AXLES TO THE FRAME OF A BOGIE OF A RAILWAY VEHICLE

Abstract: Mechanism for connecting a bush for railway vehicle axles (12) to the frame (10) of a railway vehicle bogie compris­ ing a longitudinal push rod (14) having one end (16) con­ nected to the bush (12) and its opposite end (18) connected to the frame of the bogie, with the interposition of respective elastic members comprising at the connection to the bogie frame, rubber sleeves (40). Supplementary resilient means (58) are disposed in series with the said rubber sleeves so as to increase the transverse elasticity of the connection when the transverse forces applied to the said sleeves exceed a pre determined threshold value.

Description: "Mechanism for connecting a bush for railway axles to the frame of a bogie of a railway vehicle" The present invention relates generally to the connection of a bush for railway axles to the frame of a bogie of a railway vehicle, for example, a locomotive. More particularly, the invention relates to a connection mechanism of the type comprising a longitudinal push rod having one end connected to the bush and the opposite end connected to the frame of the bogie with the inner position of respective elastic members formed by rubber sleeves designed to allow the bush free displacements in the vertical plane and limited displacements in the transverse and longitudinal directions. The object of the present invention is to provide a mechanism of the type specified above which allows the optimisation of the transverse xesilience of the connection between the bush and the frame of the bogie, with a stablising effect. According to the invention, this object is achieved by the fact that a connecting mechanism of the type defined at the beginning further comprises supplementary resilient means disposed in series with the rubber sleeves associated with the end of the push rod connected to the frame of the bogie and acting so as to increase the transverse elasticity of the said connection when the transverse forces applied to the bush exceed a predetermined threshold value. Thanks to this characteristic it is possible to impart to the resilient connection between the bush and frame of the bogie the necessary relatively high rigidity-in the case of transverse forces of limited magnitude, whilst ensuring that the said rigidity is appreciably less for transverse loads above the said predetermined threshold value, corresponding in practice to the loading of the supplementary resilient means. The result is a perceptible improvement in the travelling stability of the bogie and in its ability to adapt to line irregularities. According to a preferred embodiment of the invention two sleeves of elastomeric material are provided between the frame of the bogie and the corresponding end of the push rod, the sleeves being axially spaced, and the said supplementary resilient means consist of a helical compression spring interposed coaxially between the two rubber sleeves, the ends of said spring reaction against respective abutments which can approach each other axially, and which bear against the two rubber sleeves. Alternatively the additional resilient means may comprise cup springs or their equivalent. The invention will now be described in detail with reference to the accompanying drawings, supplied purely by way of non-limiting example, in which: - Figure 1 is a diagrammatic longitudinal sectional view of a connecting mechanism according to the invention, shown in its undeformed rest condition, and - Figure 2 shows a part of Figure 1 in its deformed condition under heavy loading. Referring initially to Figure 1, there is indicated diagrammatically at 10 a part of the frame of a railway vehicle bogie, for example of a locomotive, and at 12 one part of a bush for railway axles connected to the frame 10 by a connecting rod or a longitudinal push rod 14. The connecting rod 14 has at one end a tubular part 16 of small axial length which serves for connection to the bush 12 and at the opposite end, a tubular part 18 greater length for connection to the frame 10. The tubular part 16 is traversed axially by a connecting pin 20 which has prismatic ends 20a engaged in corresponding holes 22 in the bush 12, and a central cylindrical part 24 connected to the tubular part 16 of the connecting rod 14 through a rubber sleeve 26. Between the end faces of the tubular part 16 and the surfaces of bush 12 which face it, there are interposed two further rubber elements 28. The other tubular part 18 of the connecting rod 14 is traversed by a connecting pin 30 which has a central cylindrical part 32, two cylindrical end parts 34 of smaller diameter and two prismatic terminal parts 36 engaged in corresponding holes 38 in the frame 10. Two sleeves 40 are interposed between the cylindrical parts 34 of the pin 30 andthetubular part i8 of the connecting rod 14, each sleeve 40 including an inner metal ring 42, an inner ring44 of elastomeric material, a intermediate metal ring 46, an outer ring 48of elastomeric material and an outer metal ring 50. The inner metal rings 42 are keyed to two bushes 52 adjacent the surfaces of the cylindrical end parts 34 of the pin 30,the bushes 52 having respective external annular stop flanges 54 at their adjacent axial ends. The outer metal rings 50 of the two sleeves 40, on the other hand, are keyed to a bush 56 adjacent the inner wall of the tubular part 18 of the rod 14. The central part 32 of the pin 30 is surrounded by a helical compression spring 58 the ends of which react against a pair of abutment rings 60 slidable axially along the bush 56. Each abutment ring 60 hasan external annular axially projecting lip 62 against which the outer metal ring 50 of a respective sleeve 40 abuts, and a radially inwardly projecting flange 64 which cooperates with the annular flange 54 of the corresponding bush 52. In operation, the normal longitudinal and transverse movements of the bush 12 in relation to the frame 10 of the bogie are made possible by elastic deformations of the rubber elements 26, 28 and by radial deformations of the sleeves 40. When the magnitude of the transverse forces applied to the sleeves 40 exceeds a predetermined threshold value, then the flexibility of the resilient connection between the frame 10 and the rod 14 and hence the bush 12, is increased as a result of the compression-deformation of the helical spring 58, due to the abutment rings 60 approaching each other axially in the manner illustrated in Figure 2. Naturally, details of construction and forms of embodiment of the invention may be varied widely from what has been described and illustrated with reference to the example. More particularly the helical spring 58 could be replaced by equivalent resilient members, for example, cup springs.

Claims: CLAIMS 1. Mechanism for connecting a bush for railway axles (12) to the frame (10) of a bogie of a railway vehicle, comprising a longitudinal push rod (14) having one end (16) connected to the bush (12) and the opposite end (18) connected to the bogie frame (10) with the interposition of respective elastic members formed by rubber sleeves (26,40) designed to allow the bush free displacements in the vertical plane and limited displacements in the longitudinal and transverse directions, characterised in that the mechanism further comprises supplementary resilient means (58) disposed in series with the rubber sleeves (40) associated with the end (18) of the push rod (14) connected to the bogie frame (10) and acting so as to increase the transverse elasticity of the said connection when the transverse forces applied to the said sleeve (40) exceed a predetermined threshold value. 2. Mechanism according to Claim 1, characterised in that the axially spaced apart sleeves (40) are interposed between the bogie frame (10) and the corresponding end (18) of the push rod (14) and in that the said supplementary resilient means comprise a compression spring (58) interposed coaxially between the two sleeves (40) and the ends of which react against respective abutments (6) which can approach each other axially, and which bear against the said two sleeves (40).

Inventors: CASALONE RINALDI, ROBERTO
Applicants: FIAT FERROVIARIA SAVIGLIANO S.P.A.
Application year: 1984
Main classification: B61F15
IPC codes: B61F15, B61F5