US1734865A - Rail-bearer structure for high-speed suspended railways - Google Patents

Description

1929- KRUCKENBERG E'lfAL 1,734,865

'RAIL BEARERISTRUCTURE FOR HIGH SPEED- SUSPENDED RAILWAYS Filed March 5, 1927 2 Sheets-Sheet l Nov. 5, 1929. F. KRUCKENBERG ETAL v 1,734,865

RAIL BEARER STRUCTURE HIGH SPEED SUSiENDED RA ILWAYS Filed March 1927 2 Sheets-Sheet 2 Patented Nov. 1929 min-semen STRUCTURE non men-sense scsrnnnnn RAILWAizs Application filed March 5, 1927, Serial No. 178,197,.81'110 in Germany 'november 11, i925.

In our United States Patent No.'1,659,322, February 14, 1928, there is described a rail track for the passage of high speed suspended trains, in which the running rails are un- 5 broken over their whole length and made without 'unevc'nne'sses and held to a structure by horizontally movable or 'slidable carrier arms. The individual pieces of rail at the joints were either welded or pressed together to such an extent that gaps were in effect nonexistent;

If now instead of an expensive material which is practically indifierent to temperature changes, as for example 36% nickel steel 1 (inv'ar steel), the usual material with the usual co-eflicient of expansion is used for the rails; the necessary structure for supporting such rails must be arranged in a particular way in order to prevent the stresses which 29 are set up in the continuous rail by temperature differences, from producing such alterations in length of the rail as will endanger the security of operation and in'particular in orfirmly anchored in the ground. If therefore the running rails run unbroken for several hundred kilometers and sustain at different points in the whole length difierent tensile or cjompre'ssiye stresses caused by temperature variations, all these stresses and diflerences in the various rail lengths are transferred to the firmly anchored piers. I This transfer to the piers is further ensured by the so-called longitudinal rail carriers, which themselves sup port the lateral rail carriers and are so arranged that they can yield at their points of 5 connection to the pi'ers to compressive strains but can oppose sufficient resistance to tension. The mfa'ingirders are freely movable or extensible in "the longitudinal direction bu tween each two piers and are borne thereon, and are alsb'connectd at their mid-points a rigid manner Withthe rail's'and therefore with the longitudinal rail carriers-,1 so that their mid-points are fixed in relation to the piers at each end by the running rails.

The arrangement which is described in detail below, allows security of operation tobe achieved in the event of a rail breakage, in

that it effectually prevents the formation of a large gap at a break'in particular when considerable tensile stresses are calledinto pla over the whole length of'the rail owing to Very low temperatures. The saidarr'ange Inent also avoids buckling of the rails horizontally or vertically when high temperatures producea out the rails.

compressive stress through- In the construction of the rail carrying structure, the mean temperature of 10'15'C. is assumed for the normal mean condition of the rails and longitudinal rail sup orts. The highest value, both of the compressive'stress at the "maximum temperature and of the tensile stress at the lowest temperature, which can occur isjabo'ut 1 ,000 kg./sq. cm. which is quite inconsiderable'in-a material with ficiently high elas'tic'liinit.

a suf The construction of the rail carrying struc ture in accordance with the'inventio n and the manner in which the desired object is achieved, is explained below with reference to the accompanying drawings,- in which Fig. 1 is a perspective View of one side of parftfof the general rail-system,

Fig. 2 is a plan view of'one form of end connection of the main girder,

Fig. 3 is a side View of another form of end connection of the main girder, p Flgs. 4 and 5 are respect vely a detail cross sectlon and a side View partly in section of the longitudinal rail carrier,

rangement of the lateral rail Fig. 6 is a side vie'woffne form carriers,

showing the a1"- of end connection of the longitudinal rail carriers,

Figs. 7 and 8 are ,vemcaltmnsverse sections 'on lines A' A' and 3-H, respectively,

Fig 9 and 10 are schematic uia tms nlustrat'ing the method of anchoring the-rails at the piers, and at central spans, respectively;

portions of the Figure 1 shows the rail carrying structure with piers and one longitudinal rail carrier, on which one rail is secured. Obviously on the opposite side of the structure illustrated is another rail (not shown) with the longitudinal rail carrier appertaining thereto.

The rail supporting structure consists essentially of-the main girders a, which are supported in the usual manner, longitudinally slidable, on the piers f so that they can freely expand and contract with temperature changes. -The longitudinal rail carrier 0 is articulated to the out-rigger arms 6 extending sideways in vertical planes. In the longitudinal rail carrier 0 are mounted lateral rail carriers d which are articulated at one end to the running rail 6. These lateral carriers are provided at comparatively short intervals and are so connected to the longitudinal rail carriers 0 that they can swing in a horizontal I plane. This connection is very simply effected by flat metal strips 9 which are secured between the upper and lower flanges 1* and r of the longitudinal carriers 0 (F igures4 and 5) and on the middle parts of which are mounted the lateral carriers d. In this way the latter can yield to forces acting in the horizontal plane. I

The rails are welded together at the joints or are immovably clamped together.

The inner arms of the'lateral carriers are articulated to the lower flange a:v of the main girders a. In addition the rail e isrigidly and immovably connected to the piers f of the structure by a triangular construction 9 and with the girder a'at the centre between two piers f by a triangular construction it.

. The lateral rail carriers dvcan bend in relation to the rail e during the relative movement of the main girders and the longitudinal carriers 0 caused by temperature changes, and in consequence no unpermissible stresses are transferred to the rails. If the lateral carrier d bends the band 9 twists slightly, little resistance being offered to such twisting owing to the cross sectional form of the band. Only small forces produced by the changes in length of the main girder a and the longitudinal carrier 0 will therefore be transmitted to the rail 6. 7 V

The longitudinalrail carrier 0 is borne on the piers f at i in such a manner that itcan expand with the temperatures higher than those prevailing when it was'originally erect-- ed, so that compressive and buckling stresses are not set up in it. The main girder a can also slide in the longitudinal direction on the piers f, so that in it also, no-internal compression isset up. It can freely expand from the centre point where it is rigidly secured to the rail 6 and longitudinal rail-carrier c, in either direction, being connected at each end to the pier for example by a spring system an or Z or by a pendulum suspension 0.

Figure 2 shows the arrangement of such a spring system in plan. The sides m, m of the main girder are articulated at the ends to a laminated spring Z, pre-loaded to such an extent that the spring is always in a position to overcome the rolling friction of the longitudinally movable bearings n and n. During changes in length of themain girder the springs Z at each end ensure its being held in the mid position and inthis way no stress is produced in the rail by a change in position of the main girder a.

Another form of connection of the main girder a with the pier f is illustrated in F igure 3. Here the main girder a is held by the end of its lower flange by a suspender 0 which is secured to the pier f at p in a moment transmitting fashion.

I'Vith very low temperatures, tensile stresses occur in the rail. Since the rail on each side of the piers is securely connected to the piers, the rails over their whole lengths remain at rest. If with a high tensile stress a break occurs owing to faulty material, then the tension acting on one side in the rails of the neighbouring section will tend to twist the piers f and a large gap, dangerous for the operation of the line, may be produced at the break.

In order effectually to prevent such gaps, 4

which would render the safety of traffic doubtful, the bearing supports of the longitudinal rail carriers 0 on the piers are so constructed that during temperature higher than normal they act as plain bearings permitting longitudinal movement, but at lower than normal temperatures, prevent such movements. This can be effected for example as shown in Figure 6. The longitudinal carrier 0 is borne on the pier f on a bearing 8 permitting longitudinal movement and is connected to the pier by short eye bars t, similarly to two members of a chain. In erecting the structure, the two eye bars arefully stretched but not tensioned. If the temperature rises above the temperature. at the time of construction the longitudinal rail carrier 0 can freely expand with, and in the same manner as, the main girder a, since the eye bars, owing to the pivotal joints u' and u, cannot transmit compressive forces. On the other hand if the temperature falls below the temperature at the time of construction the longitudinal rail carrier 0 is prevented by the eye bars 25 from contracting along with the main girder a. The same temperature stresses will be set up as in the rail. the piers f therefore the longitudinal rail carriers form positive tensile connections, which undergo smaller or greater tensile stresses according to the temperature changes, for example at 30 C. and an erecting temperature of 10 to 15 0., about 1,000 kg./sq. cm. If now a rail breaks, for example at c, then the tension acting on the now free rail ends, will be transmitted to the longitudinal rail carriers 0 at the rigid connections Between 72. of the rail e thereto. These longitudinal carriers are so connected to one anotherover the piersby suitably constructed members 2' that they act at low temperatures, as tension members which by being given a suitable cross section can easily take over the extra load due to rail tension in the event of a rail breakage. Owing to the large cross sectional area of the longitudinal carriers 0 in comparison with the rail cross sectional area, the stress intensity (in kg./sq. cm.) in the carriers is not much increased. No perceptible twist of the piers f takes place, so that the only factor tending to open the gap produced by the break will be the contraction due to low temperature of the free rail ends from 'v to the nearest on a longitudinal rail carrier,

fixed holding point .9 or k. This is so small as to be allowable in practical operation.

If the temperature rises above the tempera ture at the time of construction, then, since they cannot expand, a compressive stress is set up in the rails. At 60 C. this reaches a value of about 1,000 kg./sq. cm., which in a material with a sufficiently high elastic limit for sustaining the stresses caused by the train loads and so forth, is but slight. At the same time with this compressive stress there is the risk of buckling. This is met by firmly holding the rails both in the horizontal and vertical planes by the lateral carriers d at as short intervals as possible. Owing to the short free buckling lengths thus produced and the relatively large resisting moment of the rail, the security against buckling is very high.

\Vhat we claim is 1. A rail supporting structure for high speed suspended railways having a substantially continuous welded trackway formed of jointed rails, characterized in that the rails are immovably fixed to the piers firmly enclosed in the ground, and to an intermediate portion of the supporting structure spanning the gap between adjacent piers.

2. A supporting structure for high speed suspended railways having a jointed but substantially continuous trackway, comprising spaced piers firmly anchored to the ground,

comparatively are longitudinally movably supported at each end on the piers.

6. A rail supporting structure accordin to claim 3, characterized in that the main girc ers are borne at each end by a spring suspension or other spring system in order to centre them.

7. A rail supporting structure according to claim 3, characterized in that the lateral rail carriers are connected to the longitudinal carriers so that they can swing in the horizontal plane.

8. A rail supporting structure according to claim 3, characterized in that the lateral rail carriers are of two armed form, and are pivotally connected by one arm with the rail and by the other arm with the main girder.

9. A rail supporting structure according to claim 3, characterized in that the joint between the lateral rail carrier and the longitudinal rail carrier is formed by a constructional member of such cross section as will allow it to yield rotationally.

In testimony whereof we allix our signa- FRANZ KRUCKENBERG. CURT STEDEFELD.

' tures.

supporting structures between adjacent piers,

means for supporting the trackway from said structures at a plurality of points between adjacent piers, and means for immovably fixing said trackway to said piers and to the middle of each of said supporting structures.

3. A rail supporting structure for highspeed suspended railways having a substantially continuous welded trackway formed of jointed rails, characterized in that the rails are immovably fixed to piers firmly enclosed in the ground and to an intermediate portion of the supporting structure spanning the gap between adjacent piers, wherein the lateral supports which hold the rail are supported and the longi-

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