IMPROVE- MENTS IN SIGNAL APPARATUS FOR THE PREVENTION OF ACCIDENTS ON. RAILWAYS.
Year: 1853

page_text: LETTERS PATENT to Thomas Walker, of Birmingham, in the
County of Warwick, Engineer, for the Invention of "IMPROVE-
MENTS IN SIGNAL APPARATUS FOR THE PREVENTION OF ACCIDENTS ON.
RAILWAYS.
Sealed the 5th May 1854, and dated the 7th November 1853.
PROVISIONAL SPECIFICATION left by the said Thomas Walker at
the Office of the Commissioners of Patents, with his Petition, on
the 7th November 1853.
I, THOMAS WALKER, of Birmingham, in the County of Warwick,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SIGNAL APPARATUS FOR THE PREVENTION OF ACCIDENTS
ON RAILWAYS" to be as follows:-
The improvements relate to arrangement of apparatus whereby a
passing engine or train causes signal apparatus to indicate to other suc-
ceeding engines or trains that an engine or train has just preceeded, &
consists in so arranging the apparatus that whilst one or more of the

page_text: wheels of the passing train (or it may be a projection from the side of
one of the carriages) causes the signal apparatus to indicate danger,
it also acts upon a clock-work or roast-jack movement, so as to cause
a winding up of such movement to take place, by which, when the
train is passed, such movement (which is in connexion with the signal
apparatus) immediately begins, by its unwinding, to bring the signal
apparatus gradually from indicating danger to indicate caution,. & from
caution to all clear, & the time occupied during the change from
danger to all clear may be of an hour or other period determined upon.
And it is the application of apparatus wound up by the passing of an
engine or train, so that the signal apparatus set to danger may at an
interval determined upon assume the position indicating that all is clear,
which constitutes the feature of novelty in this part of the Invention.
The improvements also consist in causing such apparatus (where
gas light is used for the night signal) to turn on a full supply of gas
to the signal lights immediately the train passes, and then to cause such
supply to be reduced gradually to a minimum of light when an interval
has elapsed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Walker in the Great Seal Patent Office
on the 6th May 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS WALKER, of Birmingham, in the County of Warwick, En-
gineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of November, in the
year of our Lord One thousand eight hundred and fifty-three, in the
seventeenth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Thomas Walker, Her
special licence that I, the said Thomas Walker, my executors, admi-
nistrators, and assigns, or such others as I, the said Thomas Walker,

page_text: my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention
for IMPROVEMENTS IN SIGNAL APPARATUS FOR THE PREVENTION OF ACCI-
DENTS ON RAILWAYS," upon the condition (amongst others) that I, the
said Thomas Walker, by an instrument in writing under my hand
and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be per-
formed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Thomas Walker, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof (that is to say):
The improvements relate to arrangement of apparatus whereby a
passing engine or train causes signal apparatus to indicate to other
succeeding engines or trains that an engine or train has just preceded,
and consists in so arranging the apparatus that whilst one or more of
the wheels of the passing train (or it may be a projection from the side
of one of the carriages) causes the signal apparatus to indicate danger,
it also acts upon a clock-work or roast-jack movement, so as to cause
a winding up of such movement to take place, by which, when the
train has passed, such movement (which is in connection with the signal
apparatus) immediately begins, by its unwinding, to bring the signal
apparatus gradually from indicating "danger" to indicate "caution,"
and from "caution to "all clear," and the time occupied during the
change from danger to all clear may be a quarter of an hour or other
period determined upon.
"
The improvements also consist in causing such apparatus (when gas
light is used for the night signal) to turn on a full supply of gas to the
signal lights immediately the train passes, and then' to cause such

page_text: supply to be gradually reduced to a minimum of light when an interval
has elapsed after the passing of the carriage or train.
But that the nature of the Invention, and the means. by which I
carry the same into effect, may be fully understood, I will proceed to
describe the Drawing annexed.
But that the nature of the Invention, and the means. by which I
carry the same into effect, may be fully understood, I will proceed to
describe the Drawing annexed.
DESCRIPTION OF THE DRAWING.
Figures 1, and 2, show two views of parts of apparatus arranged
according to my Invention. a, is one of the rails of a line of railway,
and b, b, are parts of a signal post. To the rail a, and the post b, are
affixed bearings c, and d, for the axle e, upon one end of which is
placed the lever arm e', with its outer end lying near to the inside of
the rail a, and in position to be acted upon by the flanges of the wheels
of the carriages passing along the line of rails to which that rail belongs.
Upon the other end of the axis e (which in Figure 2 is for conve-
nience of the Drawing shown with part broken away) is affixed the
lever arm e, the outer end of which is formed into a segment of teeth
taking into the small pinion f on the axis f¹, upon which is also affixed
the lever arm f in connection (by means of the rod g,) with the signal
apparatus used, so that when by the passing of the wheels of an engine
or train of carriages over the rail a, the outer end of the lever arm e¹
is depressed, as shown, the tooth segment on the arm e will be caused
to give a partial rotary motion to the pinion f, and a consequent
movement to the arm f, which, according to the arrangement which I
have shown, is connected by the rod g to the lever arm day signal h;
but this may be varied, and the connecting rod g may give motion to
other arrangement of day or night signal; but as the means for causing
such rods to actuate the required signals are well known, and form no
part of my Invention, I have not thought it necessary to show such
adaptation.
In order to prevent injury to the parts moved by the rod g, by the
sudden motion of a train acting upon the arm e', I form the rod 9, in
two parts, one of which passes through the open frame g¹ of the other,

page_text: and has a head g, between which and the upper part of the open
frame g is a spring g', which, when the lower portion of the rod g is
suddenly pulled down, admits of compression, whilst it is of sufficient
strength to cause the parts fully to act upon the signal.
Whilst by the depression of the lever arm e¹ the signal apparatus
used is caused to indicate "danger," according to my improvements
certain mechanism which I will now proceed to describe, and which is
of the character of clock-work or roast-jack movement, is wound up, in
order that immediately after the train has passed such movement may,
by the application of a suitable escapement, gradually restore the signal
to a state of rest, or that indicating all clear. To the axis fis aflixed
one end of a coiled spring contained within the box i, in such manner
that the turning of the axis f, to set the signal to danger, causes the
winding up of such spring. But in place of a coiled spring other
description of spring may be employed as the moving power. Upon
the axis f¹ is also affixed the ratchet wheel f", in the teeth of which
rests the spring click or driver j, which is carried by a pin projecting
from the side of the tooth wheel ', and when the signal is caused to
indicate danger the axis fi, and ratchet wheel f",
in one direction to wind up the spring in the
driver j slips freely over the teeth of the ratchet
diately the train has passed the power of the spring begins to act upon the
axis f to restore the signal to its original position, and again indicate
"all clear," when the click or driver j falls into one of the teeth of the
ratchet wheel, causing it to move the wheel j', which takes into the
teeth of the pinion k, affixed to or formed on the axis ', upon which
is also affixed the vertical escapement wheel k for governing the un-
winding of the spring or other power exerted upon by the axis f. The
teeth of the escape wheel are acted upon by the pallets 1, 1, on the
axis ', upon which is affixed the segment 1, with teeth which take
into teeth m, formed on or affixed to the axis m', on which is aflixed
the tooth wheel m², which takes into the teeth n, formed on or aflixed to
the axis n', all which is similar to that adopted in what are commonly
called "bottle roast jacks;" the upper end of the axis n² being. sus-
are moving round
box i; the click or
wheel f³, but imme-

page_text: pended by threads or strands of silk or worsted, and the lower end
thereof supporting a weight o, which, when the apparatus is in motion,
makes a rotation or rotations first in one direction, and then in the other,
and the velocity of motion of the escapement by which the time
occupied in bringing the signal from a position indicating "danger"
to "all clear" is regulated by the increase or decrease of diameter of
the balance wheel or weight o employed. If desired, the axis e' may
have applied to it another lever arm p, capable, as the lever arm e¹ is
being depressed, of being raised into position to act upon any suitable
apparatus carried by a locomotive engine to sound a whistle, in the
event of 'the engine driver not heeding the signal.
4
In place of the lever ärm e¹ being acted upon by the flanges of the
wheels, such lever arm may be acted upon by a projection or series of
projections from an engine or any of the carriages of a train.
Also, in place of the apparatus, when acting upon night signals,
causing the shifting of colored glasses, or the turning of the lantern
to show a different color, the connecting rod g may, when gas is em-
ployed as the illuminating means to the signal light, be connected to a
tap in the gas supply pipe, to cause a full supply of gas to be turned
on upon the arrival of a train, and to be gradually reduced to a mini-
mum of light after the train has passed any given time to indicate all
is clear.
Having thus described the nature of my said Invention, I would
have it understood that I do not confine myself to the precise details
herein shown and described, so long as the peculiar character of my
Invention be retained. But what I claim is, the arrangement and
combination of parts by which apparatus such as herein described,
forming parts of clock-work or a bottle roast-jack movement, are
caused to be wound up simultaneously with the setting, to indicate
danger, of a signal therewith connected, by the passing of an engine or
train, in order that such signal may, after the passing of such engine
or train, gradually assume a position indicating that all is clear.
Also, I claim the application of such apparatus to turn on a full
supply of gas (where gas light is used) to the signal lights immediately

page_text: a train passes, and then to cause such supply to be reduced gradually
to a minimum of light when an interval has elapsed.
In witness whereof, I, the said Thomas Walker, have hereunto
set my hand and seal, this Sixth day of May, in the year of our
Lord One thousand eight hundred and fifty-four.
Witness,
WILLIAM BROOKES,
Patent Agent,
73, Chancery Lane.
THOS WALKER. (L.B.)