Information
-
Patent Grant
-
6618963
-
Patent Number
6,618,963
-
Date Filed
Friday, June 14, 200222 years ago
-
Date Issued
Tuesday, September 16, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 037 197
- 037 198
- 348 144
- 348 147
- 348 146
- 348 98
- 348 106
- 348 135
- 348 128
- 348 125
- 701 223
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International Classifications
-
Abstract
A track maintenance machine comprises a machine frame, a track scanning unit adjustable connected to the machine frame and having flanged rollers for moving the track scanning unit along the track, a satellite receiver connected to the machine frame, the satellite receiver having an antenna with an antenna center, a measuring device for monitoring the position of the antenna center relative to the track scanning unit with respect to the following parameters: transverse track tilting (β), transverse track displacement (d) perpendicular to a longitudinal extension of the machine frame, and vertical distance (a), and a computer for a computed repositioning of the antenna center relative to a reference point of the track scanning unit.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a track maintenance machine comprising a machine frame having undercarriages for moving the machine frame in an operating direction along a track, and a track scanning unit adjustably connected to the machine frame and having flanged rollers for moving the track scanning unit along the track. This invention also relates to a method of monitoring a track position.
2. Description of the Prior Art
A machine and method of this type is known, for example, from EP 0 806 523 A1. The position of a track lifting device, which senses the track position, is measured relative to a machine frame of the track maintenance machine, and the machine frame position is determined by means of geodetically measured fixed points defining the absolute track position.
Furthermore, it is known from DE 41 02 871 C2 to measure the displacement of a track scanning unit, such as a measuring axle rolling on a track, relative to a machine frame of a track tamping machine running on the track.
Finally, EP 1 028 325 A2 discloses a method of measuring a track position by means of two independently moving measuring carriages positioned on the track at the end points of a track section to be measured.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a machine and method of this general type, which enables the position of a track to be monitored quickly and with dependable accuracy.
According to one aspect of the present invention, this object is accomplished with a track maintenance machine of the first-described type, which comprises a satellite receiver connected to the machine frame, the satellite receiver having an antenna with an antenna center, a measuring device for monitoring the position of the antenna center relative to the track scanning unit with respect to the following parameters: transverse superelevation (β), transverse displacement (d) perpendicular to a longitudinal extension of the machine frame and vertical distance (a), and a computer for a computed repositioning of the antenna center relative to a reference point of the track scanning unit.
Such a machine makes it possible to obtain an exact parallel guidance of the antenna center relative to the center axis of the track, despite a front arrangement of the satellite receiver on the machine frame, which assures an optimal reception of the extraterrestrial position signals by the satellite receiver.
According to another aspect of this invention, a method of monitoring a track position by scanning the track comprises the steps of determining the position of an antenna center of an antenna of a satellite receiver receiving extraterrestrial position signals relative to a reference point on a track scanning unit adjustably connected to a machine frame of a track maintenance machine and having flanged rollers for moving the machine frame in an operating direction along the track, the satellite receiver also being connected to the machine frame, and automatically recording the absolute track position coordinates in the range of the track scanning unit by determining the coordinate position of the antenna center by means of the position signals.
BRIEF DESCRIPTION OF THE DRAWING
The above and other objects, advantages and features of the invention will become more apparent from the following detailed description of now preferred embodiments thereof, taken in conjunction with the drawing wherein
FIG. 1
shows a side elevational of a track maintenance machine according to the present invention;
FIG. 2
is an enlarged, schematic cross sectional view along line II—II of
FIG. 1
; and
FIGS. 3
,
4
and
5
diagrammatically illustrate different steps of the method of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2
illustrate a track maintenance machine
1
comprising machine frame
2
having undercarriages
3
for moving the machine frame in an operating direction indicated by arrow
8
along track
4
. Driver's and operator's cabs
5
as well as power unit
6
are provided on machine frame
2
. As disclosed in EP 1 028 325 A2 and, therefore, not further described, satellite carriage
7
carrying laser transmitter
29
is movable on track
4
independently of machine
1
for measuring the existing position of the track in front of the machine, in the operating direction.
Track scanning unit
9
is adjustably connected to machine frame
2
and has flanged rollers
10
for moving the track scanning unit along the track. In the illustrated embodiment, the track scanning unit comprises measuring axle
11
connected to laser receiver
28
for generating measuring line
30
in conjunction with laser transmitter
29
. Measuring axle
11
is pivotally linked to machine frame
2
forwardly of front undercarriage
3
, with respect to the operating direction indicated by arrow
8
. Drives (not shown to avoid crowding of the drawing) vertically adjustably connect measuring axle
11
to machine frame
2
to enable the measuring axle to be lowered onto the track for engagement of flanged rollers
10
with track rails
12
at the beginning of the measuring operations.
Satellite receiver
13
is fixedly connected to machine frame
2
, the satellite receiver having antenna
14
with antenna center
15
for receiving extraterrestrial position signals (GPS-signals) emitted from space satellites. As shown in
FIG. 1
, antenna
14
of satellite receiver
13
is connected to machine frame
2
directly above track scanning unit
9
.
Measuring device
16
monitors the position of antenna center
15
relative to track scanning unit
9
with respect to the following parameters indicated in FIGS.
3
-
5
: track superelevation (β), transverse track displacement (d) perpendicular to a longitudinal extension of the machine frame, and vertical distance (a). The illustrated measuring device is a laser scanner
17
connected to the machine frame, the laser scanner generating a scanning plane
18
extending transversely to the longitudinal extension of the machine frame from a point of origin
19
. Point of origin
19
forms optical center
24
of measuring device
16
relative to the longitudinal extension of the machine frame and is arranged on underside
27
of machine frame
2
aligned with, and above, track scanning unit
9
. Scanning target
20
is centered on track scanning unit
9
between flanged rollers
10
for being scanned by laser scanner
17
, and reference point
22
is also centered between the flanged rollers. The illustrated scanning target is a ruler
21
extending transversely to the longitudinal extension of machine frame
2
and the reference point is a peg
23
projecting from the ruler. Computer
25
serves for a computed repositioning of antenna center
15
relative to reference point
22
of track scanning unit
9
.
The method of monitoring a track position by scanning track
4
will be explained in connection with
FIGS. 3
,
4
and
5
. This method comprises the steps of determining the position antenna center
15
of antenna
14
of satellite receiver
13
receiving extraterrestrial position signals relative to reference point
22
on track scanning unit
9
adjustably connected to machine frame
2
of track maintenance machine
1
and having flanged rollers
10
for moving machine frame
2
in operating direction
8
along track
4
. Satellite receiver
13
also is connected to machine frame
2
. The absolute track position coordinates are automatically recorded in the range of track scanning unit
9
by determining the coordinate position of antenna center
15
by means of the position signals.
The position of antenna center
15
relative to track scanning unit
9
is determined with respect to the following parameters: track superelevation (β), transverse displacement (d) perpendicularly to the longitudinal extension of machine frame
2
, and vertical distance (a). When the track position is determined by scanning track
4
, and taking these parameters into account, computer
25
on machine
1
will automatically produce a repositioning of antenna center
15
relative to reference point
22
of track scanning unit
9
. In other words, the position of antenna center
15
of satellite receiver
13
mounted on machine frame
2
relative to reference point
22
of track scanning unit
9
linked to the machine frame and running on track
4
is determined, whereby the absolute track position coordinates in the range of track scanning unit
9
are automatically recorded by means of the position of the coordinates of antenna center
15
obtained by the extraterrestrial position signals (GPS-signals).
FIG. 3
schematically illustrates the measurement of the transverse inclination of machine frame
2
relative to measuring axle
11
of track scanning unit
9
. Normally, because of shock absorbers on undercarriages
3
supporting machine frame
2
on track
4
, the machine frame will have a transverse inclination differing from that of measuring axle
11
, whose inclination corresponds to superelevation (β) of track
4
. This difference in the transverse inclinations of machine frame
2
and measuring axle
11
is ascertained by laser scanner
17
establishing an xy coordinate system whose zero-point is in point of origin
19
of scanning plane
18
generated by the laser scanner. Coordinates x
1
, y
1
and x
2
, y
2
of the outermost laser beams impinging upon transversely extending ruler
21
are calculated in the coordinate system in computer
25
, and the computer accordingly calculates the inclination (α) of machine frame
2
. Since angle (α) only indicates the angle between machine frame
2
and measuring axle
11
, it is necessary to determine the absolute inclination of the machine frame relative to the horizontal. For this purpose, the transverse inclination of measuring axle
11
, which corresponds to track superelevation (β), is measured by inclinometer
26
mounted on the measuring axle. The value of angle (α) is subtracted from that of angle (β) to obtain the absolute inclination of machine frame
2
.
FIG. 4
schematically illustrates the calculation of vertical distance (a) between measuring axle
11
and machine frame
2
. Laser scanner
17
delivers for every step a measurement of the angle as well as of the vertical distance from scanned ruler
21
. Thus, projecting peg
23
centered on ruler
21
and forming reference point
22
is clearly identified by laser scanner
17
, and its horizontal and vertical position relative to point of origin
19
is clearly determined. Therefore, it is possible to ascertain the vertical and horizontal distance between measuring axle
11
and machine frame
2
. To find reference point
22
(peg
23
), that scanning beam which shows a minimal distance in the center is selected from the distance measurements of laser scanner
17
. This scanning beam characterizes vertical distance (a) and the angle (δ) in coordinate system xy, wherein machine frame
2
forms the x-axis and the zero-point lies in point of origin
19
of laser scanner
17
. In this way, reference point
22
is fixed in this coordinate system by means of values (a) and (δ).
Since the coordinate system first deviates from the horizontal by the inclination of the machine frame, the computer must turn the entire coordinate system to the horizontal by the value of the angle of the machine frame inclination to make it possible to calculate the vertical and horizontal distance from the zero point.
FIG. 5
schematically illustrates the use of the essential parameters in the method of this invention. Before the scanning operation of track maintenance machine
1
begins, the following constants are ascertained:
h=vertical distance of antenna center
15
of satellite receiver
13
from point of origin
19
of laser scanner
17
.
d=horizontal distance of antenna
14
and its center
15
from point of origin
19
of laser scanner
17
.
b=distance of the inner edge of track rail
12
from reference point
22
on ruler
21
.
c=vertical distance of ruler
21
and its reference point
22
from the upper edge of track rail
12
.
The measurements described hereinabove in connection with
FIGS. 3 and 4
produce the following values:
α=relative transverse inclination of machine frame
2
.
β=superelevation of track
4
, which corresponds to the transverse inclination of measuring axle
11
.
δ=angle at which laser scanner
17
identifies peg
23
(reference point
22
).
a=distance between point of origin
19
of laser scanner
17
and reference point
22
on ruler
21
, as measured by the laser scanner.
The vertical and horizontal distances between the GPS-antenna
14
and the contact point of track scanning unit
9
with rails
12
is computed on the basis of these data.
Claims
- 1. A track maintenance machine comprising(a) a machine frame having undercarriages for moving the machine frame in an operating direction along a track, (b) a track scanning unit adjustably connected to the machine frame and having flanged rollers for moving the track scanning unit along the track, (c) a satellite receiver connected to the machine frame, the satellite receiver having (i) an antenna with an antenna center, (d) a measuring device for monitoring the position of the antenna center relative to the track scanning unit with respect to the following parameters: superelevation (β), transverse displacement (d) perpendicular to a longitudinal extension of the machine frame and vertical distance (a), and (e) a computer for a computed repositioning of the antenna center relative to a reference point of the track scanning unit.
- 2. The track maintenance machine of claim 1, wherein the measuring device is a laser scanner connected to the machine frame, the laser scanner generating a scanning plane extending from a point of origin transversely to the longitudinal extension of the machine frame.
- 3. The track maintenance machine of claim 2, wherein a scanning target is centered on the track scanning unit between the flanged rollers for being scanned by the laser scanner, and the reference point is also centered between the flanged rollers.
- 4. The track maintenance machine of claim 3, wherein the scanning target is a ruler and the reference point is a peg projecting from the ruler.
- 5. The track maintenance machine of claim 1, wherein an optical center of the measuring device relative to the longitudinal extension of the machine frame is arranged on an underside of the machine frame above the track scanning unit.
- 6. The track maintenance machine of claim 1, wherein the track scanning unit comprises a measuring axle connected to a laser receiver for generating a measuring line, and the measuring axle is pivotally linked to the machine frame forwardly of a front undercarriage with respect to the operating direction.
- 7. The track maintenance machine of claim 1, wherein the antenna of the satellite receiver is connected to the machine frame above the track scanning unit.
- 8. A method of monitoring a track position by scanning the track, which comprises the steps of(a) determining the position an antenna center of an antenna of a satellite receiver receiving extraterrestrial position signals relative to a reference point on a track scanning unit adjustably connected to a machine frame of a track maintenance machine and having flanged rollers for moving the machine frame in an operating direction along the track, the satellite receiver also being connected to the machine frame, and (b) automatically recording the absolute track position coordinates in the range of the track scanning unit by determining the coordinate position of the antenna center by means of the position signals.
Priority Claims (1)
Number |
Date |
Country |
Kind |
488/2001 |
Jun 2001 |
AT |
|
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4700564 |
Prasil et al. |
Oct 1987 |
A |
5481479 |
Wight et al. |
Jan 1996 |
A |
6356299 |
Trosino et al. |
Mar 2002 |
B1 |
Foreign Referenced Citations (6)
Number |
Date |
Country |
4222 333 |
Jan 1993 |
DE |
41 02 871 |
Aug 1999 |
DE |
0 806 523 |
May 1996 |
EP |
0722 013 |
Jul 1996 |
EP |
1 028 325 |
Jan 2000 |
EP |
2240 570 |
Aug 1991 |
GB |