US3484043A

US3484043A - Systems for holding rails on sleepers of railway tracks

Info

Publication number: US3484043A
Application number: US691614A
Authority: US
Inventors: Lennart Borup; Per-Erik Olson
Original assignee: Individual
Current assignee: PER ERIK OLSON
Priority date: 1966-12-20
Filing date: 1967-12-18
Publication date: 1969-12-16
Anticipated expiration: 1986-12-16

Description

L. BoRuP ET'A'L SYSTEM FOR HOLDl NG RAILS 0N SLEEPERS OF RAILWAY TRACKS Filed. Dec. 18, 1967 Fig. 3

Fig. 5

nited States Patent Q US. Cl. 238233 19 Claims ABSTRACT OF THE DISCLOSURE In a system for holding rails on sleepers of railway tracks of the class comprising resilient fastener means for holding the rails on the sleepers, and a pad between each sleeper and each rail, said pads are of a special structure or shape allowing the rails to perform free bending movements around geometric axes substantially parallel to the sleepers and within limits determined by the resiliency of the fasterner means and by the bending resistance of the rails, while therey during loading of the track by a train relieving the sleepers within said limits from substantial forces otherwise tending to tilt them around their longitudinal axis, the sleepers thus taking substantially no part in the bending vertical movement of the rail.

The invention refers to an improved system for holding rails on sleepers of railway tracks, comprising resilient fastener means and pads between the rails and the sleepers.

Still, the railway sleepers are to a great extent made of wood. Certainly the utilization of concrete has increased, but there are several circumstances that have caused certain limitations regarding the utilization of concrete as a material for railway sleepers. One reason is that the wood with respect to resiliency and damping has more favourable dynamic characteristics than the concrete which on account of its great coefiicient of elasticity and low internal damping also under very good ballast conditions generally has to be combined with some form of pads of wood, rubber or the like in order to reduce the dynamic strains under the force applied from the train via the rails.

The rubber pads hitherto generally used in connection with concrete sleepers are usually symmetric and homogeneous or uniform in the lognitudinal direction of the sleepers and as far as known also symmetric and homegeneous or uniform in the longitudinal direction of the track, said pads thus presenting a constant characteristic of resiliency in the longitudinal and transversal directions of the sleeper. This fact together with the commonly used rail fastener means in which rigid spring elements are provided for holding the rails on the concrete sleepers, has the consequence that the sleepers under high pressure of the wheels will tilt backwards and forwards around its longitudinal axis as the wheel on the rail is rolling over the sleeper. This means that the location of the sleeper in the bed is subjected to a never-ceasing repetition of mechanical influences, resulting in changes of the sleeper and the bed. Thereby the holding of the sleeper in the bed is soon impaired, the degree of compaction of the bed is rendered ununiform and thus the position of the track is impaired.

The object of the invention is to avoid a tilting of the sleeper as the wheels are rolling over the same, and thereby eliminate the disadvantages resulting therefrom as mentioned above.

The invention is based on a system in which resilient fastener means are provided for holding the rails on the sleepers, and a preferably resilient pad is disposed between each sleeper and each rail, and the characterizing novel feature of the invention is that the pads are of a special structure allowing the rails to progressively perform free bending movements downwards and upwards around geometric axes substantially parallel to the sleepers and within limits determined by the resiliency of the fastener means and by the bending resistance of the rails, whereby during loading of the track by a train the sleepers are within said limits relieved from substantial forces otherwise tending to tilt them around their longitudinal axes.

When utilizing resilient fastener means which are made with a certain resiliency of sufiicient magnitude in the vertical direction, the system according to the invention has the effect that the rail under the Wheels passing over the same will perform a controlled bending movement in a longitudinal vertical plane without transferring the loading forces, progressively varying along the rail, completely to the sleeper just being passed by the wheel, said loading forces being through the rail distributed also to the adjacent sleepers and thereby a reduced distributing effect on the location of the sleeper in the bed being attained.

The invention will be described more detailed in the following specification and with reference to the accompanying drawing in which two possible embodiments are illustrated by way of example in FiGS. 1 and 2 and a preferred embodiment is illustrated by way of example in FIGS. 3, 4 and 5.

In the drawings:

FIG. 1 illustrates one embodiment of the pad at the right-hand rail and the other embodiment of the pad at the left-hand rail, as seen in a cross-section transversal to the track and in the longitudinal direction of a sleeper;

FIG. 2 illustrates the right-hand embodiment of FIG. 1, as seen in a cross-section transversal to the sleeper and along the line IIII in FIG. 1;

FIG. 3 is a transversal cross-section through a rail together with a pad of a third embodiment illustrated more clearly in FIGS. 4 and 5;

FIG. 4 is a plan of the pad of FIG. 3 on a greater scale;

FIG. 5 is an end-view of the pad, corresponding to the plan of FIG. 4-.

In the following specification, the invention will at first be explained in connection with the preferred embodiment according to FIGS. 3, 4 and 5.

To the sleeper 1, which is a concrete sleeper, the rail 2 is clamped by means of a resilient fastener device 3. According to FIG. 3 this rail fastener device is in wellknown manner made as a bow-shaped steel fork, having its two legs extending downwards at both sides of the. sleeper and being held under tension under a peg 4 inserted through the sleeper, while the two end-portions of the fork (one end closed, as to the right in FIG. 3, and the other end open, as to the left in FIG. 3) are. curved over the respective side portions of the rail base for exerting a pressure downwards on the same.

According to FIGS. 3, 4 and 5, the pad 5 disposed between the sleeper and the rail, is shaped as a plate consisting of a resilient material, preferably with a rather high degree of resiliency, such as vulcanized rubber or a corresponding plastic or the like.

This resilient pad 5 is of a structure providing a resiliency increasing from the central portion of the pad in the longitudinal direction of the rail towards the transversal edges T of the pad for allowing a vertical bending movement of the rail in relation to the sleeper, preferably a vertical movement of the rail of at least 1 millimeter at said transversal edge T. This increased resilience at the transversal edges T can be produced by making recesses in the pad at both edges T. For example, these recesses can be three grooves 6 (and in the longitudinal direction of the rail) some distance over the pad in the top surface of the same. In the bottom surface of the pad there are made four similar grooves 7 which however are somewhat staggered in relation to the grooves 6 of the. top surface. In this way the end portions of the pad adjacent to the transversal edges T are capable of yielding more than the central portion of the pad.

Preferably, the resilient pad is of such a structure providing also a resiliency increasing from the central portion of the pad in the transversal direction of the rail towards the lateral or side edges S of the pad for allowing also a rotary movement of the rail around its longitudinal axis. This increased resiliency at the side edges S of the pad can be produced by making recesses in the pad at both edges S. For example, these recesses can be four grooves 8 which extend in parallel to the side edges S of the pad over the entire length of the same in its top surface, and are disposed only in the side portions of the pad, while no such groove is provided centrally. In a similar way, four throughgoing grooves 9 are disposed in the bottom surface of the pad, but somewhat staggered in relation to the grooves 8 of the top surface. The

long grooves

8, 9 and the outer

short grooves

6, 7 are. located so that the grooves will be distributed more closely in the portions adjacent to the side edges S. In the top surface of the pad (FIG. 4) this is indicated by the distance a greater than the distance b and by the distance a greater than the distance b In this way also the side portions of the pad near to the side edges S will be capable of yielding more than the central portion of the pad.

If desired, the pad can be made with a thickness in creasing like a wedge towards the outer side of the rail of the track in order to promote a limited rotation of the rail around its longitudinal axis under the action of vertical and horizontal forces.

According to FIG. 2 and the right-hand portion of FIG. 1, the pad 5a can be 'a substantially semi-cylindrical body which is disposed so as to have its semicylindrical surface mounted in a corresponding recess in the sleeper 1. The axis of the semi-cylindrical surface is parallel to the sleeper 1, thus transversal to the rail 2. The pad 5a can consist for instance of a plastic, such as nylon, which can be self-lubricating, if desired. Also in connection with pads of this structure, resilient fastener devices 3a are utilized, for instance in the form of hookshaped nails or spikes, which are hooked into a recess made. in the sleeper, said spike having its upper end portion made with a horizontal resilient 100p (diagrammatically shown to the right in FIG. 1). In this embodiment the rail can perform a bending movement downwards and upwards around an axis parallel to the sleeper without affecting the position of the sleeper, but the rail cannot rotate around its longitudinal axis.

It should be understood that when the pad allows a rotation of the rail around the longitudinal axis of the same, this rotary movement will take place only within narrow limits, determined by the resilient fastener devices and by the torsional resistance of the rail.

We claim:

1. In combination,

an elongated railway rail;

a sleeper for the rail disposed therebeneath;

pad means interposed between the sleeper and the rail mounting the rail on the sleeper, said pad means providing a variable resistance to downward movement of the rail diminishing from the center of said pad means outwardly longitudinally of said rail to facilitate rotative movement of the rail relative to the sleeper about a horizontal axis extending substantially perpendicularly of the rail; and

resilient fastener means yieldably interconnecting the A rail and the sleeper, whereby during loading of the track by a train the sleeper is not subjected to substantial forces which would otherwise tend to rotate the sleeper.

2. Sturucture as set forth in claim 1 wherein said pad is substantially symmetrical relative to said axis to facilitate substantially equal rotation of the rail in either direction from its normal position about said axis.

3. Structure as set forth in claim 1 wherein said pad comprises a body having a semi-cylindrical outer surface, said sleeper having a recess therein presenting a concave semi-cylindrical surface having its axis disposed concentrically with said horizontal axis, said pad being disposed in the recess with said surfaces slidingly engaged to permit rotation of the pad about said axis and thereby facilitate rotation of the rail relative to the sleeper.

4. Structure as set forth in claim 1 wherein said pad comprises a resilient, compressible plate having a pair of spaced side portions and a central portion disposed between the side portions, said side portions each having a greater compressibility than said central portion, said plate being disposed with said side portions spaced longitudinally of the rail.

5. Structure as set forth in claim 4 wherein said plate includes means positioned at each side portion thereof to modify the normal compressibility of the plate.

6. Structure as set forth in claim 5 wherein each of said means includes groove defining means.

7. Structure as set forth in claim 6 wherein each groove defining means presents a plurality of grooves extending longitudinally of the rail.

8. Structure as set forth in claim 7 wherein the grooves of each side portion extend inwardly of the plate from the outer side of the side portion toward said central portion.

9. Structure as set forth in claim 8 wherein some of the grooves of each side portion are longer than others or the grooves of the same side portion whereby the compressibility of each side portion increases in a direction from the central portion and toward the outer side of the side portion.

10. In a rail support,

a plate of resilent and compressible material adapted for inter-positioning between a rail and a sleeper for the rail in supporting relationship to the rail,

said plate having a pair of spaced side portions and a central portion disposed between the side portions interconnecting the same,

said plate being positionable beneath the rail with said side portions spaced longitudinally of the rail,

said side portions each having a greater compressibility than said central portion whereby to permit rotative movement of the rail relative to the sleeper about a horizontal axis extending substantially perpendicularly of the rail.

11. A rail support as set forth in claim 10 wherein is included resilient fastener means for yieldably interconnecting the sleeper and the rail to maintain the pad therebetween.

12. A rail support as set forth in claim 10 wherein said plate has a pair of spaced lateral edge segments and a central segment disposed between the edge segments interconnecting the same, said edge segments being disposed to be positioned on opposite sides of the rail when said side portions are spaced longitudinally of the rail. said edge segments each having a greater compressibility than said central segment whereby to also permit rotative movement of the rail relative to the sleeper about an axis extending longitudinally of the rail.

13. A rail support as set forth in claim 12 wherein is included resilient fastener means for yieldably interconnecting the sleeper and the rail to maintain the pad therebetween.

14. A rail support as set forth in claim 10 wherein said plate includes means positioned at each side portion thereof to modify the normal compressibility of the plate.

15. A rail support as set forth in claim 14 wherein each of said means includes groove defining means.

16. A rail support as set forth in claim 15 wherein each groove defining means presents a plurality of grooves disposed to extend longitudinally of the rail.

17. A rail support as set forth in claim 16 wherein the grooves of each side portion extend inwardly of the plate from the outer side of the side portion toward said central portion.

18. A rail support as set forth in claim 17 wherein m some of the grooves of each side portion are longer than others of the grooves of the same side portion whereby the compressibility of each side portion increases in a direction from the central portion and toward the outer side of the side portion.

19. A rail support as set forth in claim 18 wherein said plate has spaced lateral edges disposed to be positioned on opposite sides of the rail when the side portions are spaced longitudinally of the rail, said grooves being distributed more closely together in the segments of the plate adjacent said edges whereby the compressibility of said segments is greater than the compressibility of the central segment of the plate to thereby permit rotative movement of the rail relative to the sleeper about an axis extending longitudinally of the rail.

References Cited UNITED STATES PATENTS 3,369,753 2/1968 Olson 233-2b3 FOREIGN PATENTS 724,388 2/1955 Great Britain, 854,063 11/1960 Great Britain.

15 ARTHUR L. LA POINT, Primary Examiner RICHARD A. BERTSCH, Assistant Examiner US. Cl. X.R.