Railways: surface track – Rails – Turnout
Reexamination Certificate
1999-06-30
2001-07-10
Morano, S. Joseph (Department: 3617)
Railways: surface track
Rails
Turnout
C238S027000
Reexamination Certificate
active
06257494
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a base structure of a turnout for a permanent way and, more particularly, to a base structure of a turnout capable of reliably preventing the occurrence of alignment deviation.
BACKGROUND OF THE INVENTION
For a base structure of a turnout for a permanent way, it is conventional to place wooden sleepers for the turnout in the track bed ballast at predetermined intervals and at right angles to the rail. Most sleepers used for the turnout are made of wood. Wooden sleepers are used because it is possible to place a base plate on the sleepers in the field, and to easily fix the base plate on the sleepers with track spikes or screw spikes by adjusting the position, then mount a rail on the base plate. Recently, sleepers made of synthetic resin or prestressed concrete are being used in place of the wooden sleepers.
Alternatively, a steel sleeper
21
having a cross section of substantially trapezoidal shape and a hollow inner space which opens at the bottom has been proposed, as shown in
FIG. 12
, wherein the inner space is filled with ballast to prevent the sleepers from subsiding, and both end faces of the sleeper in the longitudinal direction thereof are closed by press, thereby preventing the sleepers from moving in the direction of gauge, i.e., the so-called alignment deviation, by means of the ballast which fills the inner space of the sleeper.
The turnout comprises, as major components, a point section
22
, a lead section
23
, a crossing section
24
and a guard section
25
, as shown in FIG.
13
. In any one of these sections, rails
27
are mounted on the sleepers
26
with a positional relationship successively varying. Rails
27
and sleepers
26
are not at right angles with each other, and the crossing angle also is successively changing. The length of the sleeper also must be changed according to where it is positioned.
Thus, the turnout is very fragile because of its complicated structure compared to ordinary rail sections, and has shorter service life due to the use of wooden sleepers which tend to rot. More-over, sleepers used for a turnout generally are longer than the regular sleepers used in ordinary tracks, and, therefore, are more difficult to handle. Consequently, sleepers used for a turnout require more labor when being replaced.
Thus, it is very desirable to prevent damage or any other trouble from occurring to the sleepers to the utmost. However, a rail in a turnout has a radius of curvature which is generally smaller than in ordinary tracks, which causes a train running thereon to exert a sufficiently large lateral force that results in a displacement of the sleepers. As a result, it is necessary to frequently perform rail maintenance to correct the alignment deviation in order to prevent derailment accidents due to the alignment deviation.
In this respect, a conventional sleeper for a turnout provides a large resistive force to prevent the displacement in the longitudinal direction of the track by means of the ballast packed between the sleepers. However, with respect to the displacement in the direction perpendicular to the track, a conventional sleeper for a turnout provides a resistive force only with ballast built up on the track bed shoulder of both ends of the sleeper, which is not sufficient to prevent alignment deviation caused by a lateral force exerted on the track.
On the other hand, sleeper
21
, as shown in
FIG. 12
, requires the ballast to be pressed toward the bottom of the sleeper by tamping the ballast from the side of the sleeper with a tie tamper in order to fill the inner space of the sleeper
21
with the ballast. This operation is very tedious and often results in insufficient packing of the ballast. Insufficient packing of the ballast leads to subsidence of the sleeper and poor resistance against a force exerted in the direction perpendicular to the track, which causes a displacement in said direction.
The present invention solves the problems of the above-described prior art, and an object of the present invention is to provide a base structure of a turnout which has high durability and is capable of reliably preventing lateral displacement.
SUMMARY OF THE INVENTION
In order to accomplish the above-described object, the first aspect of the present invention provides a base structure of a turnout used in a ballast track bed comprising a plurality of sleepers having substantially same configuration, but different lengths, wherein the sleepers are placed in parallel to each other, at predetermined intervals, such that the length of the sleepers changes stepwise from the short sleepers to the long sleepers. In addition, both end faces in the longitudinal direction of all the sleepers are capped with sleeper tie members, with part or all of the sleeper tie members being embedded in the ballast.
The second aspect of the present invention provides a base structure of a turnout used in a ballast track bed comprising a plurality of sleepers having substantially same configuration, but different lengths, wherein the sleepers are placed in parallel to each other, at predetermined intervals, such that length of the sleepers changes stepwise from the short sleepers to the long sleepers, and all the sleepers are tied each other by two sleeper tie members at positions located inward from both ends of the sleeper in the longitudinal direction thereof.
The third aspect of the present invention provides the base structure of a turnout of the second aspect, wherein the sleepers are tied each other by two sleeper tie members at positions located below rails.
According to the present invention, both end faces in the longitudinal direction of the plurality of sleepers of different lengths are capped with sleeper tie members, or sleepers are tied each other by two sleeper tie members at positions located inward from both ends of the sleeper in the longitudinal direction thereof, such that the plurality of sleepers act collectively as an integral base structure of a turnout. Therefore, the base structure of a turnout has a great resistive force against a force exerted in the direction perpendicular to the track, thus providing considerably greater resistance against an alignment deviation.
The third aspect of the present invention, where the sleepers are tied each other by two sleeper tie members at positions located below rails, has such an advantage that there is no portion which causes trouble when tamping the ballast beneath the sleeper with a tie tamper.
The sleeper tie members which tie a plurality of sleepers together are joined to the sleepers by means of track spikes, screw spikes, bolts and nuts, or welding, and the like.
REFERENCES:
patent: 4756476 (1988-07-01), Fasterding et al.
patent: 5222662 (1993-06-01), Floter
Demura Masafumi
Ego Mitsuki
Fukui Yoshihiro
Irie Takaaki
Konishi Katsuniri
Marshall O'Toole Gerstein Murray & Borun
McCarry, Jr. Robert J.
Morano S. Joseph
Yamato Kogyo Co., Ltd.
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