U.S. patent number 3,636,508 [Application Number 05/012,360] was granted by the patent office on 1972-01-18 for systems for transmitting information between a railway track and moving train.
This patent grant is currently assigned to British Railways Board. Invention is credited to Harry Heggie Ogilvy, Clive Valentine Smith.
United States Patent |
3,636,508 |
Ogilvy , et al. |
January 18, 1972 |
SYSTEMS FOR TRANSMITTING INFORMATION BETWEEN A RAILWAY TRACK AND
MOVING TRAIN
Abstract
A system for transmitting information between a trackway and a
moving vehicle and of the kind in which one or more coils laid on
the trackway become inductively coupled with aerial means on the
vehicle, the bit of information transmitted by the or each coil
being distinguished as "1" or "0" (using conventional binary
notation) by utilizing the antiphase relationship of the flux
parallel to the plane of the turn(s) of the coil associated with
the two opposite sides of the coil. An additional bit of
information can be derived from each coil by utilizing the flux
perpendicular to the plane of the turn(s) of the coil.
Inventors: |
Ogilvy; Harry Heggie
(Middlesex, EN), Smith; Clive Valentine (Kempston,
EN) |
Assignee: |
British Railways Board
(N/A)
|
Family
ID: |
9873842 |
Appl.
No.: |
05/012,360 |
Filed: |
February 18, 1970 |
Foreign Application Priority Data
|
|
|
|
|
Feb 21, 1969 [GB] |
|
|
9,533/69 |
|
Current U.S.
Class: |
246/8; 379/55.1;
246/2E |
Current CPC
Class: |
B61L
3/22 (20130101) |
Current International
Class: |
B61L
3/22 (20060101); B61L 3/00 (20060101); B61l
001/00 () |
Field of
Search: |
;246/8,63A,2 ;179/82
;340/32,47 |
Foreign Patent Documents
Primary Examiner: La Point; Arthur L.
Assistant Examiner: Libman; George H.
Claims
We claim:
1. A system for transmitting binary coded data from a wayside data
transmitting location to a moving vehicle comprising:
A. a plurality of spaced, horizontally disposed, discrete conductor
loops at said location and positioned sequentially in the direction
of vehicle movement along the wayside and with the vertical axis of
at least one conductor loop on the opposite side of a line
extending parallel to the direction of movement of the vehicle to
at least one other conductor loop,
B. an alternating current source for energizing each said conductor
loop producing a magnetic field above each loop which has a
vertical component which is either of a first relative phase or a
second opposite relative phase dependent upon the direction of
current flow in said loop and which has a first horizontal
component to one side of said axis of a first relative phase and a
second horizontal component to the other side of said axis of a
second opposite relative phase,
C. detector means disposed on the vehicle to move along said line
and including,
i. first aerial means oriented to be inductively coupled with said
vertical component of magnetic field of each conductor loop in
sequence,
ii. second aerial means adapted to be inductively coupled with the
nearer of said first and second horizontal components of magnetic
field of each conductor loop in sequence,
iii. said first aerial means being responsive to an inductive
coupling with one said conductor loop which provides a vertical
magnetic field of said first phase to provide a first phase
manifestation representative of a "one" bit and being responsive to
an inductive coupling with one said conductor loop providing a
magnetic field of said second opposite phase to provide a second
phase manifestation representative of a "zero" bit,
iv. said second aerial means being responsive to an inductive
coupling with said first component of horizontal magnetic field of
one said conductor loop to provide a third phase manifestation
representative of a "one" bit and being responsive to an inductive
coupling with said second component of horizontal magnetic field of
one said conductor loop to provide a fourth phase manifestation
representative of a "zero" bit, and
D. decoder means responsive to the reception of said first, second,
third and fourth phase manifestations to provide a composite signal
representative of the binary coded data transmitted from the
wayside to said vehicle.
2. A system for transmitting binary coded data between a
transmitting station and a receiving station as said one station
passes the other said station and comprising in combination:
A. at least one transmitting loop at said transmitting station,
B. means for energizing said transmitting loop with an alternating
current to thereby produce a first component of flux in a plane
normal to the plane of said transmitting loop and with a first
relative phase or a second opposite relative phase dependent upon
the direction of current flow in said loop and for also producing
second components of flux parallel to the plane of said loop one of
which lies laterally to one side of the axis of said loop and the
other of which lies laterally to the other side of the axis of said
loop,
C. and two receiving loops at said receiving station and each
passing through an inductive coupling relationship with said
transmitting loops as said transmitting and receiving stations pass
each other,
D. one of said receiving loops being so oriented and positioned
that it has inductively coupled therein a distinctive voltage
signal only in response to said first component of flux and with
the induced signal having a distinctive waveshape dependent upon
the polarity of energization of said transmitting loop,
E. a second receiving loop being so oriented and positioned that
there is induced therein a distinctive voltage signal only in
response to said second components of flux,
F. each said transmitting loop being selectively positionable in
either of two distinctive positions laterally spaced relative to a
line defined by the path of relative movement of said second
receiving loop as said one station passes said other station so
that in one of said two positions said second receiving loop has
induced therein a distinctive voltage signal in response to said
one horizontal component of flux and in the other of said positions
said second receiving loop has induced therein a distinctive
voltage signal in response to said other horizontal component of
flux,
G. and decoder responsive to the distinctive voltage signals
induced in said first and second receiving coils.
3. The system of claim 2 in which said transmitting station is on
the track wayside and said other station is on a train.
4. The system of claim 3 in which said transmitting loops are
positioned adjacent the track rails.
5. The system of claim 4 in which said transmitting loops and said
second receiving loop are all horizontally oriented and said first
receiving loop is vertically oriented.
6. The system of claim 5 in which said transmitting loops are all
mounted adjacent a track rail and are selectively positionable to
either side of said rail dependent on the code to be transmitted to
the train.
Description
This invention relates to systems for transmitting information
between a trackway and a moving vehicle, for example between a
railway track and a moving train, of the kind in which a coil
(hereinafter termed a telegram coil) laid on the trackway and
energized by alternating current becomes inductively coupled with
aerial means on the vehicle in order to transmit a signal between
the trackway and the vehicle.
In British Pat. specifications, Nos. 1,107,028 and 1,147,289 are
described systems of this kind for transmitting from a railway
track to a moving train local information related to features of
the track, e.g., gradient, line speed, station identification etc.,
the systems having a number of telegram coils arranged one after
the other along the track at a local information point, one bit of
information being derived from the vertical component of field
produced by each telegram coil (i.e., the component of field
perpendicular to the plane of the turn(s) of the coil). The bits of
information are provided in a binary (i.e., two state) code by
virtue of telegram coils laid oppositely to one another producing
inductive couplings with the aerial means in antiphase with one
another.
The object of this invention is to provide a system enabling two
bits of information to be extracted from a single telegram
coil.
According to this invention, in a system of the kind described for
transmitting information between a trackway and a moving vehicle,
said aerial means is sensitive to the flux substantially parallel
to the plane of the turn(s) of said telegram coil, and said
telegram coil is positioned on the trackway so that one part of the
turn(s) of said coil is nearer than the opposite part of the
turn(s) of said coil to the line of movement of said aerial means
resulting from movement of the vehicle, whereby the aerial means is
predominantly influenced by the component of flux associated with
the nearer part of the turn(s) of said telegram coil. Since the two
components of flux associated respectively with said two opposite
parts of the turn(s) of the coil are in antiphase a bit of
information can be derived by the aerial means from the telegram
coil which in conventional binary notation is either "1" or " 0." A
second bit of information can be derived from the flux
perpendicular to the plane of the turn(s) of the same telegram coil
in the manner described in British Pat. specification, Nos.
1,107,028 and 1,147,289.
The invention will now be further explained with reference to the
accompanying drawings in which:
FIG. 1 defines the "X," "Y" and "Z" axes referred to in the ensuing
description.
FIG. 2 shows one arrangement of telegram coils in plan view for
producing a multidigit message.
FIG. 3 is a cross section through one of the rails of the track to
show the arrangement of the telegram and aerial coils.
FIGS. 4 to 7 are explanatory diagrams, and
FIGS. 8 and 9 are tables showing two possible forms of coded
information obtained from the arrangement of FIG. 7.
Referring now to FIG. 1, a telegram coil 1 is laid on the track
with its plane horizontal so that the "Z" axis is in a vertical
plane and the "X" and "Y" axes are in a horizontal plane, the "Y"
axis extending in the direction along the track and the "X" axis
therefore extending transversely of the track. The origin is the
center of the coil.
In FIG. 2, three such telegram coils 1, 2 and 3 are shown connected
in series with parallel wires 4 and 5 to an alternating current
source 6, the parallel wires 4 and 5 extending along the track.
Aerial means 7 is mounted on a train and, resulting from the
movement of the train, has the line of movement 8.
Referring to FIG. 3, one convenient physical arrangement of the
telegram and aerial means is shown, the aerial means 7 having a
line of movement over the center of one rail 9 of the track and the
coils 1 to 3 being located on the foot of the rail 9 through
supports 10. The coil 11 of the aerial means 7 is sensitive to the
horizontal component of flux B.sub.x and the coil 12 is sensitive
to the vertical component of flux B.sub.z.
FIG. 7 shows the flux distribution around any one of the telegram
coils 1 to 3 for a given instantaneous direction of current through
the coil. If the vertical component of flux density B.sub.z is
plotted against Y, the curve in FIG. 4 is obtained for a given
height Z above the coil. If the horizontal transverse flux density
B.sub.x is plotted against X the curve of FIG. 5 is obtained. If
the horizontal transverse flux density B.sub.x is plotted against Y
for the value of X> 0, that is for a point to the right of the
line 13 in FIG. 7, the curve of FIG. 6 is obtained and if B.sub.x
is plotted against Y for a value of X< 0, that is for a point to
the left of line 13, the mirror image of the curve of FIG. 6 is
obtained so that the values of B.sub.x are negative.
In all the curves of FIGS. 4 to 6, a change in sign of flux density
indicates a phase change of 180.degree. in the alternating flux
being produced by the telegram coil, thus a value of flux density
indicated as positive is in antiphase with a value of flux
indicated as negative.
From FIG. 5 it can be seen that proceeding from one side part of
the telegram coil to the opposite side part a phase change of
180.degree. occurs in the flux. Hence by positioning of the
telegram coils 1 to 3 relative to the line of movement of the
aerial 7 as shown in FIG. 2 the aerial means is predominately
influenced by one or other of these antiphase components of
horizontal flux B.sub.x, while the B.sub.z - Y variation shown in
FIG. 4 remains of one phase. If the telegram coil is turned over,
i.e., changed from the position shown for coil 1 to that shown for
coil 2, then all phases are reversed by 180.degree..
Assuming the convention that the signal derived in the aerial coil
12 from flux B.sub.z is "1" when B.sub.z is in phase with a
comparison signal derived from the parallel wires 4 and 5 and "0"
when in antiphase, the bit of information derived by aerial coil 11
from one or other of the antiphase values of B.sub.x depending upon
which of the antiphase components of B.sub.x is nearer 11 can be
evaluated in two ways. These are
1. comparing the phase of signal derived from B.sub.x with that of
a signal derived from parallel wires 4 and 5, or
2. comparing the phase of signal derived from B.sub.x with the
phase of signal derived from B.sub.z.
Referring again to FIG. 7 which shows the lines of flux around a
telegram coil at a given instant in time, if aerial coil 11 is as
shown then, with the assumed convention, if the derived signals
from B.sub.z and B.sub.x are all compared with the signal derived
from the parallel wires 4 and 5, the table of FIG. 8 holds. If on
the other hand the phase of the B.sub.x signals are compared with
the phase of the B.sub.z signals, the table of FIG. 9 holds, where
the two columns (a) and (b) under B.sub.x relate to the flux
associated with part of the telegram coil to the left and part to
the right of the line 13 respectively in FIG. 7.
Assuming that the table of FIG. 8 is the relevant one and the bit
of information derived from the B.sub.z flux of telegram coil 1 is
a "1," then the multidigit message made up of the bits of
information derived from the B.sub.z fields of coils 1 to 3 is "1,"
"0," "1" and the composite multidigit message derived from the
B.sub.x fields of coils 1 to 3, if the direction of winding of coil
11 with respect to the coil 1 is as shown in FIG. 7, would be "0,"
"0," "1." The decoder 14 responds to the different distinctive
voltage signals induced in the coils 11 and 12 of aerial means 7 to
produce distinctive output signals representative of these multibit
messages.
* * * * *