U.S. patent number 3,638,482 [Application Number 04/822,966] was granted by the patent office on 1972-02-01 for method and apparatus for indicating track conditions.
This patent grant is currently assigned to Franz Plasser Bahnbaumaschinen. Invention is credited to Egon Schubert.
United States Patent |
3,638,482 |
Schubert |
February 1, 1972 |
METHOD AND APPARATUS FOR INDICATING TRACK CONDITIONS
Abstract
Changes in acceleration caused by local track conditions are
directly or indirectly measured as a car moves over a track
section. The resultant signals are totalled to produce a signal or
parameter characteristic of the track section condition, and this
is compared with a comparison signal characteristic of a track
condition norm.
Inventors: |
Schubert; Egon (Vienna,
OE) |
Assignee: |
Franz Plasser Bahnbaumaschinen
(Vienna, OE)
|
Family
ID: |
3582895 |
Appl.
No.: |
04/822,966 |
Filed: |
May 8, 1969 |
Foreign Application Priority Data
|
|
|
|
|
Jun 25, 1968 [OE] |
|
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A 6104/68 |
|
Current U.S.
Class: |
73/146 |
Current CPC
Class: |
G01M
99/00 (20130101); B61K 9/08 (20130101) |
Current International
Class: |
B61K
9/08 (20060101); B61K 9/00 (20060101); G01M
19/00 (20060101); B61k 009/08 () |
Field of
Search: |
;73/146 ;33/144,145 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Woodiel; Donald O.
Claims
What is claimed is:
1. A method of indicating the condition of a railway track,
comprising the steps of moving a car over a plurality of successive
sections of the track, the velocity of the car being constant in
each track section, producing individual signals corresponding to
local changes in acceleration transversely of the direction of
elongation of the track, said acceleration changes being due to
changing local conditions of the track, totaling the individual
signals, the values of the individual acceleration changes being
based on a uniform car velocity, to produce an indicium
characteristic of the condition of the track consisting of the
successive track sections, and comparing the indicium with a like
indicium of a track condition norm measured at the same
velocity.
2. The method of claim 1, wherein said acceleration changes are
measured electrically and said signals are electric.
3. The method of claim 1, wherein changes in acceleration are
separately measured in two different planes, and said changes are
transformed into said measuring signals.
4. The method of claim 3, wherein said planes are perpendicular to
each other.
5. The method of claim 4, wherein one of said planes is defined by
the track and the other plane extends perpendicularly thereto in
the direction of the track.
6. The method of claim 3, wherein the vector sum of all of said
indicium is established to arrive at said characteristic
signal.
7. The method of claim 1, wherein indicia corresponding to the
local positions of the track are measured, and the measured values
of the local track positions are transformed into said individual
signals corresponding to the local acceleration changes.
8. The method of claim 7, wherein said indicia are the radii of
successive curves whose totality constitutes the track position.
Description
BACKGROUND SUMMARY OF THE INVENTION
The present invention relates to improvements in track
surveying.
In U.S. applications Ser. Nos. 813,854 and 813,855 filed Apr. 7,
1969, entitled "Track Surveying Method and Apparatus" and "Track
Surveying," for instance, of which the present inventor is a joint
inventor, track-measuring cars are disclosed which continuously
measure and record parameters characteristic of the track
condition, such as track gage, superelevation, curvature, grade,
etc. Such surveys are designed to establish the safety of the track
for given train speeds and determine when track maintenance work is
required to bring the track back to the desired norm.
In modern, high-speed track maintenance operations, it is essential
to determine the locations where track correction work must be
done, and it has been proposed to use computers to evaluate signals
characteristic of given measured track conditions, such as
superelevation, grade and alignment. For instance, a norm may be
established for each condition, i.e., curvature, superelevation,
track gage, grade, these conditions may be continuously measured as
a surveying car moves over the track, and deviations from the norm
may be measured and fed to a computer which will determine when the
track section falls below a given norm by counting the number of
deviations in this section. While a variety of surveying methods
have been tried, it has not been possible to set up a single
characteristic value which generally indicates the entire track
condition and is determinative of the safety of the track.
It is accordingly a primary object of the present invention to
provide a railway track surveying method and apparatus which uses a
single characteristic datum fully reflective of the track condition
so that the quality of the track is established by this single
parameter or signal.
This and other objects of this invention are accomplished by using
as datum the acceleration changes caused by varying local track
conditions in the track section being surveyed. The data are
related to an assumed uniform speed of a vehicle passing over the
track section and they are totalled to produce a parameter or
signal characteristic of the track section condition, which signal
or parameter is compared with a comparison parameter or signal
characteristic of a track condition norm.
It has been found that this single datum related to the
acceleration changes actually fully reflects all factors
responsible for the quality of the track.
It is preferred to establish data corresponding to the acceleration
changes in two mutually perpendicular planes, for instance one
defined by the track and the other one perpendicularly extending in
the direction of the track. The signals or parameters are
separately measured in the two planes, preferably electrically or
electronically, and then combined into a characteristic datum,
preferably by a vector sum.
The acceleration changes may be measured directly, i.e., by an
accelerometer mounted on a car moving over the track at a
controllable and measurable speed.
It is also possible, however, to determine the acceleration changes
indirectly without using a car with an accelerometer. For instance,
changes in a parameter characteristic of successive portions of the
track section may be measured, for instance the radii of successive
circular arcs which are assumed to form the continuous track
section. In this case, the faulty condition of the track section is
considered as a succession of curves of the same mathematical
function, for instance a series of successive circular arcs. A
parameter of these successive curves and the changes in this
parameter are measured, and the corresponding acceleration changes
of an imaginary vehicle running over the track section is derived
from these measurements and evaluated as though the acceleration
changes themselves had been measured.
DETAILED DESCRIPTION OF DRAWING
The above and other objects, advantages and features of the present
invention will become more apparent from the following detailed
description of certain preferred embodiments of the method and
apparatus useful for carrying out the method, taken in conjunction
with the accompanying drawing wherein
FIG. 1 is a chart aiding in an understanding of the method;
FIG. 2 is a schematic side view of an apparatus useful for carrying
out the method;
FIG. 3 is a top view of FIG. 2;
FIG. 4 illustrates the geometry of the measurements carried out by
the apparatus of FIGS. 2 and 3;
FIG. 5 is a schematic front view of the apparatus of FIG. 2;
FIGS. 6 and 6a illustrate measuring instruments useful in the
apparatus of the invention;
FIG. 7 is a diagrammatic illustration of another useful measuring
instrument;
FIGS. 8, 9, 11 and 12 schematically show other embodiments of
measuring instruments; and
FIG. 10 is an end view of the instrument of FIG. 9.
DETAILED DESCRIPTION
Referring first to FIG. 1, which illustrates the concept of the
method of the present invention, the curve in line A of the drawing
shows the vertical accelerations measured in a vehicle moving over
track sections I-II and II-III. The numerals in line B indicate the
absolute changes in acceleration indicated by the curve in line A,
line C indicating the sum of these absolute acceleration changes in
the two track sections. Analogous curves, values and sums for the
acceleration in a horizontal plane are given in lines D, E and F.
The approximate vector sums of the sums are given in lines G and F
(for the accelerations in two mutually perpendicular planes). Line
H indicates the actual speeds of the vehicle in the two track
sections in kilometers per hour. Line J gives the ratio of the
squares of a comparison speed of 100 km./h. and the actual speeds,
multiplied by the vector sum of line G.
Totaling the two parameters of line J, the value in line K reflects
the sum of the acceleration changes in track section I-III, based
on a comparison speed of 100 km./h. If as shown in line L, the
experimentally obtained standard or normal parameter for a speed of
100 km./h. is 50 for track section I-III, the track condition given
in line M is reflected by the ratio of the actual value 56 to the
standard value 50, i.e., 56:50= 1.12. In other words, the track
condition in track section I-III deviates from the standard
condition by 12 percent and, therefore, requires correction.
In the illustrated example, the vector sums are given only
approximately for track sections I-II and II-III. If computers are
used, exact vector sums may readily be obtained even for very small
track sections, for instance for lengths of a yard or less.
The method of this invention may also be practiced without
reference to the speed of the measuring car traveling over the
track section whose condition is to be ascertained. If the
incorrect position of the track or the individual track rails is
considered as a succession of curves of the same mathematical
function, for instance as circular arcs, the acceleration f in each
arc is determined by the equation
f= V.sup. 2 /13 H,
wherein V is the vehicle speed and H is the radius of arc. In
closely adjacent track points I and II, the respective
accelerations will be
f.sub. I = V.sup. 2 /13 H.sub. I and f.sub. II = V.sup. 2 /13
H.sub. 2
The change in the acceleration between two closely adjacent points
is equal to the difference of the accelerations:
If the ordinate or height of the arc h is measured at the point of
division of a chord having the length a+ b meters (see FIG. 4), h=
500 ab/H millimeters.
If it is desired to measure not h but h.sub. I, the equation is
Therefore, as seen in FIG. 4, only the difference between the
ordinates h.sub. I and h.sub. II positioned in space need be
measured, and the proportional acceleration changes may be readily
derived therefrom.
FIG. 2 shows a schematic side view of a surveying apparatus with
two measuring bogies 4 and 5 which move on a track 3 which is
curved in a vertical plane, the two bogies being held at a constant
distance by a coupling rod K.
Two axles 1 and 2 of the measuring bogies 4, 5 are positioned
approximately at the height of the point of gravity of conventional
railroad cars. Centrally between the rigidly spaced bogies, the two
axles of the bogies are spaced by distance v which is proportional
to the difference of the heights of the arcs of the curved track
beneath the bogies.
FIG. 3 shows the same surveying apparatus in schematic top view,
the track shown to be curved also in a horizontal plane. Thus,
there is also a distance w between the two axles 1 and 2 which is
proportional to the difference of the heights of the arcs in the
horizontal plane of the track.
In the geometrical projection of FIG. 4, there is shown the
geometrical relationship between ordinate h and h.sub. I. Points
E.sub.1 and E.sub.2 are the end points of axles 1 and 2 at the
midpoint of the distance between the two measuring bogies. The
distance h.sub. I -h.sub. II constitutes the vector sum of the
parameters w and v. FIG. 5 shows the apparatus of FIGS. 2 and 3 in
a schematic front view to illustrate this relationship.
The horizontal component w and the vertical component v may also be
obtained by using a pendulum or a gyroscope, and the horizontal and
vertical differences of acceleration may be determined by vectors,
may be totaled continuously as the surveying apparatus moves over
the track section, and the results may be compared continuously
with a standard or norm to obtain an accurate picture of the track
condition.
This condition may also be obtained by reading the results of a
track surveying bogie which measures the vertical heights of the
arc l and r, respectively, of the left and right track rail as well
as the horizontal height of the arc of the outer track rail in a
curve. In this calculation, it is assumed that the position of the
track rails projected into a horizontal and into a vertical plane
is a succession of curves of the same mathematical function, for
instance successive circular arcs.
Characteristic values of these arcs or the changes in these values
are measured, for instance changes in the radius of the arcs, and
the accelerations and/or changes in the acceleration in a
horizontal and/or vertical direction are derived therefrom. The
change in acceleration has been indicated above by the following
equation:
If the height of the arc h is measured at the midpoint of a chord
which is s meters long,
The acceleration change f.sub. I -f.sub. II is thus derived from
the change in the height of the arc.
The horizontal acceleration changes are obtained in changes of the
horizontal curvature of the track with
The acceleration changes for track superelevations are derived as
follows:
An error in the superelevation produces a horizontal movement of
the point of gravity. A sinuous error thus produces a sinuous
movement of the point of gravity. Centrifugal accelerations in a
horizontal direction of the following magnitude are exerted upon
the point of gravity:
The differences between the heights of the arc are measured in a
conventional manner, their vector sums are determined, and these
sums are compared with a comparison norm.
FIG. 6 illustrates an apparatus for inductively measuring the
distance. As shown, the end points E.sub.1 and E.sub.2 of the axles
1 and 2 of the two measuring bogies carry respective plates 6 and
6' whereon there are mounted windings 7 and 7', respectively, which
preferably extend radially, as seen in the front view of FIG. 6a.
Plate 6 is fixedly mounted on its axle while plate 6' is axially
movable towards and away from the axially fixed plate. Plate 6' is
universally mounted on ball-and-socket joint 9 and biased against
plate 6 by helical spring 8. Both plates are coated with an
insulating film 10 for gliding contact between the plates. The
winding 7 is in circuit with a source 11 of alternating current.
The power lines emanating from winding 7 cut across winding 7' and
there produce an induction current whose potential is measured by
voltmeter 12. When the two plates are moved in relation to each
other, the portions of the contacting surfaces are changed
correspondingly, thus changing the induction current which,
therefore, becomes a measure varying with the relative positions of
the end points of the measuring bogie axles.
The plates 6, 6' may also be constituted as condensers, in which
case the films 10 form the dielectric. The circuit for such an
arrangement is shown in FIG. 7 wherein the plates 6, 6' form the
condenser in circuit with a source 13 of alternating current of
high frequency. When the two plates are moved in relation to each
other, the ammeter 14 will indicate the electrical current
corresponding to the varying areas of contact between the two
plates.
It is also possible to mount on bogies 4 and 5, as well as on axles
1 and 2, accelerometers. The difference in the indicated values
produces a measure of the track condition dependent on the
measuring speed.
FIGS. 8 to 10 illustrate, by way of example, other apparatus
mounted on the axle ends of the measuring bogies of determining
their position relative to each other.
FIG. 8 illustrates mechanical measuring of the vertical distance
between the ends E.sub.4 and E.sub.5 of the two bogies. Pulleys 16
and 17 are respectively mounted on the ends of the bogies, and a
wire or rope 15 is trained over these pulleys and, if desired, an
additional guide roller 18, one end of the wire or rope being
fixedly anchored to one bogie end, i.e., E.sub.4, while the other
end of the wire or rope is attached to spring 19 on the other bogie
to keep the wire or rope tensioned. The wire or rope moves a
recording stylus 20 which records a curve 22 indicating the
vertical distances v on a paper band 21 or like record carrier. A
like arrangement for the horizontal produces a record of the
horizontal distances w.
FIGS. 9 and 10 are examples wherein the axle ends E.sub.1 and
E.sub.2 carry plates 6a and 6a'. The plates carry electrical
measuring instruments indicating the varying distances between the
axle ends. In the illustrated embodiment, the instruments are
windings receiving cores axially moving therethrough, the vertical
distances being measured by instrument 23 and the horizontal
distances by instrument 24. If the minor error derived from mutual
rotation of the plates in respect of each other is neglected, the
two instruments produce the components v and w indicating the
varying distances of the axle ends.
Since the various electrical measuring instruments are well known,
the drawing has not been encumbered with showing the current
sources, circuits, amplifiers, etc.
FIG. 11 shows an embodiment wherein the magnitude of the distance
between the axle ends E.sub.4 and E.sub.5 is measured. The axle
ends have respective brackets 25 and 26 rotatably mounted therein.
An electrical measuring instrument 27 is mounted between the two
brackets. Furthermore, a mechanical guide 28, which consists of two
telescoping tubes, is also mounted between the brackets to protect
the electrical measuring instrument 27 from all transverse forces.
The mechanical guide is connected to the brackets by universal
joints 29, 29 to enable even minor relative movements of the axles
to be read by the electrical measuring instrument.
It is desirable to make it possible for an individual in charge of
a track maintenance operation to determine the condition of a track
section. Therefore, it is quite useful to provide an apparatus for
carrying out the invention which may be readily transported. Such
an apparatus may include instruments which may be mounted on
conventional railway cars or measuring bogies for cooperation so as
to produce the desired values. Such instruments may be mounted, for
instance, at the ends of railway cars which are coupled together in
a train so that the relative position of the car ends may be
measured as the train passes over a track section whose condition
is to be surveyed.
FIG. 12 illustrates such an arrangement by way of example. The
instruments more fully described and illustrated in FIGS. 6 and 6a
are mounted on a carrier 32 which may be carried by shoulder straps
30. Setscrews 31 on the carrier are adjusted to mount the
instruments properly on the ends of cars 4' and 5'. The carrier
housings hold the circuitry and meters which record the
readings.
Other modifications and variations will readily occur to those
skilled in the art after benefiting from the present teaching
without departing from the scope of this invention.
* * * * *