IM- PROVEMENTS IN SIGNALS FOR RAILWAYS, AND IN APPARATUS FOR ACTUATING THE SAME
Year: 1858

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent and Engineer, for the Invention of “IM-
PROVEMENTS IN SIGNALS FOR RAILWAYS, AND IN APPARATUS FOR ACTUATING
THE SAME." A communication from Auguste Lucien Verité and Julien
Stephane Bazin.
Sealed the 3rd May 1859, and dated the 9th November 1858.
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the 9th
November 1858.
I, WILLIAM CLARK, of 58, Chancery Lane, in the County of Middlesex,
Patent Agent and Engineer, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN SIGNALS FOR RAILWAYS, AND IN APPARATUS FOR
ACTUATING THE SAME," to be as follows:-
This Invention consists of apparatus for ensuring the proper control of
trains which follow one another on the same line. The arrangements of
apparatus allow of the motion of the train itself being used for changing or
modifying the signals of the signal posts, and this to a certain extent according
to the position of the train on the line.
This apparatus consists of three parts; 1st, a new arrangement of signal
post; 2ndly, an apparatus serving to change the signals of open line to closed
line when a train passes in front of the signal post; 3rdly, an apparatus for
re-establishing the signal of open line after the train has passed a certain
limit. These apparatus are represented in the accompanying Drawing, in
which Fig. 1 is a view of the signal disc in its position for an open line.

page_text: Fig. 2 is a view of the signal disc in its position for a closed line. Fig. 3 is a
vertical section of the first apparatus to be placed on the signal post. Fig. 4
is a vertical section of the second apparatus placed at a limited distance from
the post. Figs. 5 & 6 show the detail of the commutator when an electric
pile is employed.
The same letters of reference indicate like parts in all the Figures where
they recur. In this improved signal the same colors are employed as for
ordinary signals, viz., red indicating a closed line, and white an open line.
a, flat disc, having two circular openings a', a¹; when the line is open the
openings remain uncovered, and the face of the signal appears entirely white,
but if the line is closed, two red discs are caused to appear through the
circular openings. b, hollow column of cast iron supporting the disc, and
-placed at the side of the line; c, treadle placed close to the rail, and projecting
a little beyond it at a certain elevation. The front wheel of the locomotive
acts on this treadle for producing the different movements of the signal
discs, it oscillates on a stud d, its other extremity being fixed to a piston
rod i; h, rigid rod terminated by an eye e, to which is attached the treadle c;
this latter, when pressed upon by the engine wheel, acts upon rod h; g, spiral
spring fixed to the rod h, which is distended by the downward motion of this
rod, and intended for returning the treadle to its original position after the
train has passed over it, which spring, if free to act in the above manner,
'would, while restoring the treadle to its position, subject it to a succession of
shocks produced by contact with the wheels of all the carriages in a train.
To obviate this inconvenience as a counteraction to the spring, a means has
been devised for, the purpose of retarding the acțion of the spring, which
consists of a cylinder j, in which a liquid is placed, freezing only at a very
low temperature, such as mercury for example, so that if when the treadle is
raised the piston in this cylinder is at the lower part, all the liquid will be
above the piston, while the train in passing lowers the treadle, which oscillating
on its centre will raise the piston rod to which it is attached; the liquid then
passes to the lower part of the cylinder through a small hole in the piston.
When the treadle is lowered, and the spring thereby distended, and when
the treadle no longer offers any resistance to it, the spring acts on one of its
extremities for the purpose of returning it to its original position, and forces
the piston attached to its other extremity to descend in the cylinder, where it
meets with the resistance offered by the mercury, so that all the mercury con-
tained in the cylinder must be raised to the surface of the piston by passing
through the small opening to admit of the treadle rising to its former position.
This flow of mercury is regulated according to the time that a train of great

page_text: length takes to pass, and this before the treadle rises. The treadle when
depressed under the action of the train causes the rod to descend, whereby
the small chain k attached to its upper extremity which supports a weight m,
is pulled; this weight, fixed on one of the arms of a bent lever l, being no
longer kept back, bears upon one arm of the bent lever until the opposite arm
presses on a stud pin n fixed on the axis of the discs for turning it in order to
bring the red disc before the openings a', a¹; on this axis is fitted an arm o¹,
which catches in a bent lever p; one extremity of this lever of soft iron serves.
as an armature for the electro-magnet 7, herein-after described.
For the arrangement above described, the signal post iudicates that the line
is closed. The second apparatus is placed at a certain distance from the signal
post, which is previously determined for greater security. In this apparatus
it is also the train which gives the primary movement to the different parts of
the apparatus. u, treadle upon which the wheel of the locomotive acts, of
which the progress is to be indicated; f¹, rod oscillating freely on rod i, con-
nected to treadle u by a rod t'; e, e', counteracting spring fixed to rod fl
for effecting the same movements as that described for the first apparatus; n,
pump of the same description, and for the same purpose as the former one; i,
rigid rod terminated by a head of soft iron c', which serves as an armature
to the magnet p¹ oscillating on point d'; q', induction coils which take a
current of induction from magnet p', when it is separated from the armature;
7, wire conductors of the current communicating with the electro-magnet 9 of
the first apparatus.
The action of the apparatus is as follows:-The train after having caused
the red disc to be placed in position, continues on its way; when at a pre-
determined distance it meets with a treadle u, which it forces down; the
treadle u in its downward motion actuates the rod "; the latter strikes
against the plate l', closely connected to rod f¹, and which consequently.
transmits the shock to the rigid rod i, the head c¹ of which detaches itself
from the magnet at the moment the armature detached; a current of induc-
tion is formed in the coils; this current passes through the wires, and animates
the electro-magnet of the first apparatus; this magnet q attracts one arm of
the bent lever p, by which movement the other arm of the lever disengages
the arm o¹, which hold the red discs in their position; the discs are then free
to return to their previous vertical position, which is effected by means of the
weight o", placed on one side of their surface, in which position the red discs
are no longer visible, and this position the disc on the sigual post will indicate
that the line is clear. It will be thus easily understood by the different
operations of the apparatus, how a train, after leaving a certain part of the
:

page_text: line may leave on its passage precise indications of the spot where it is sub-
sequently for a given time.
It has been seen that a train in its passage meets with a treadle which it
forces down, and by this means causes the red discs to appear on the signal
post, which indicates when it has passed that the line is closed during its
progress; the train then meets at a certain distance with another treadle,
which it presses down in the same way, and which serves to produce a current
of electricity for the purpose of returning the discs to their original position to
show that the line is open or clear. After a certain time, as herein-before
described, the treadles are returned to their original position, for the purpose
of recording the movement of a subsequent train.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Clark in the Great Seal Patent Office on the 7th
May 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of Nov, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Clark, Her special licence that I, the said William Clark, my
executors, administrators, and assigns, or such others as I, the said William
Clark, 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 SIGNALS FOR
RAILWAYS, AND IN APPARATUS FOR ACTUATING THE SAME," a communication from
Auguste Lucien Verité and Julien Stephane Bazin, upon the condition
(amongst others) that I, the said William Clark, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, 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.

page_text: NOW KNOW YE, that I, the said William Clark, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say):
This Invention relates to apparatus for ensuring the proper control of trains.
which follow one another on the same line. The arrangements of apparatus.
allow of the motion of the train itself being used for changing or modifying
the signals of the signal posts, and this to a certain extent according to the
position of the train on the line."
This apparatus consists of three parts; 1st, a new arrangement of signal
post; 2ndly, an apparatus serving to change the signals of open line to
closed line when a train passes in front of the signal post; 3rdly, an apparatus
for re-establishing the signal of open line after the train has passed a certain
limit. These apparatus are represented in the accompanying Drawing, in
which Fig. 1 is a view of the signal disc in its position for an open line;
Fig. 2 is a view of the signal disc in its position for a closed line; Fig. 3 is a
vertical section of the first apparatus, to be placed on the signal post; Fig. 4
is a vertical section of the second apparatus, placed at a limited distance from
the post; Figs. 5 and 6 show the detail of the commutator when an electric
pile is employed.
The same letters of reference indicate like parts in all the Figures where
they recur.
In this improved signal the same colors are employed as for ordinary signals,
viz., red indicating a closed line, and white an open line. a, flat disc having
two circular openings a', a"; when the line is open these openings remain
uncovered, and the face of the signal appears entirely white, but if the line is,
closed two red discs are caused to appear through the circular openings;
b, hollow column of cast iron supporting the disc, and placed at the side
of the line; c, treadle placed close to the rail, and projecting a little
beyond it at a certain elevation. The front wheel of the locomotive acts
on this treadle for producing the different movements of the signal discs, it
oscillates on a stud d, its other extremity being fixed to a piston rod i;
h, rigid rod, terminated by an eye which is attached to treadle c;
this latter pressed upon by the engine wheel acts upon rod h; g, spiral
spring fixed to the rod h, which is distended by the downward motion of
this rod, and intended for returning the treadle to its original position after
the train has passed over it, which spring, if free to act in the above manner,
would, while restoring the treadle to its position, subject it to a succession of

page_text: shocks produced by contact with the wheels of all the carriages in a train.
To obviate this inconvenience as a counteraction to the spring, a means has
been devised for the purpose of retarding the action of the spring, which con-
sists of a cylinder j, in which a liquid is placed freezing only at a very low
temperature, such as mercury, for example, so that if, when the treadle is
raised, the piston in this cylinder is at the lower part, all the liquid will be
above the piston, while the train in passing lowers the treadle, which oscillates
on its centre, & will raise the piston rod to which it is attached; the liquid-
then passes into the lower part of the cylinder through a small hole in the
piston. When the treadle is lowered and the spring thereby distended, and
when the treadle no longer offers any resistance to it, the spring acts on one
of its extremities for the purpose of returning to its original position, and.
forces the piston attached to the other extremity to descend in the cylinder,
where it meets with the resistance offered by the mercury, so that all the
mercury contained in the cylinder must be raised to the surface of the piston
by passing through a small opening to admit of the treadle rising to its
former position.
This flow of mercury is regulated according to the time that a train of great
length takes to pass, and this before the treadle rises. The treadle when
depressed under the action of the train, causes the rod h to descend, whereby
the small link k attached to its upper extremity, which supports a weight m,
is pulled; this weight fixed on one of the arms of a bent lever l, being no
longer kept back, bears upon one arm of the bent lever until the opposite arm
presses on a stud pin n fixed on the axis of the discs for turning it, in order to
bring the red discs before the openings a', a"; on this axis is fitted an arm o¹,
which catches in the bent lever p; one extremity of this lever of soft iron
serves as an armature for the electro-magnet q, herein-after described.
In the arrangement above described the signal post indicates that the line
is closed.
The second apparatus is placed at a certain distance from the signal post,
which is previously determined. In this apparatus it is also the train which
gives the primary movement to the different parts of the apparatus. s,
treadle, upon which the wheel of the locomotive acts of which the progress is
to be indicated; f¹, bar, oscillating freely on rod i', connected to treadle s by a
rod t; e, e, counteracting spring fixed to bar f₁, for effecting the same
movement as that described for the first apparatus; n¹, pump of the same
description, and for the same purpose as the former one; ³, rigid rod terminated
by a head of soft iron c¹, which serves as an armature to the magnet pl
oscillating on point d'; q', induction coils, which take a current of induction

page_text: from magnet p¹ when it is separated from the armature; r, wire conductors of
the current, communicating with the electro-magnet 9 of the first apparatus.
The action of the apparatus is as follows:-The train, after having caused the
red disc to be placed in position, continues on its way, when at a distance
predetermined it meets with the treadle s, which it forces down; the treadle s
in its downward motion actuates the bar f¹; this latter strikes against the
plate closely connected to rod i', and which consequently transmits the shock
to the rigid rod i, the head c¹ of which detaches itself from the magnet; at
the moment the armature becomes detached, a current of induction is formed
in the coils; this current passes through the wires, and animates the electro-
magnet of the first apparatus. The magnet 9 attracts one arm of the bent
lover p, by which movement the other arm of the lever disengages the arm o¹
which held the red discs in their position; the discs are then free to return to
their previous vertical position, which is effected by means of the weight o"
placed on one side of their surface, in which position the red discs are no
longer visible, and in this position the disc on the signal post. will indicate
that the line is clear.
It will thus be easily understood by the different operations of the apparatus
how a train after departing from a certain part of the line may leave in its
passage precise indications of the spot where it is subsequently for a given
length of time. It has been seen that the train in its passage meets with a
treadle, which it forces down, and by this means causes the red discs to appear
on the signal post, which indicates when it has passed that the line is closed;
during its progress the train meets at a certain distance with another treadle,
which it presses down in the same way, and which serves to produce a current
of electricity for the purpose of returning the discs to their original position,
to show that the line is open or clear. After a certain time as herein-before
described, these treadles are returned to their original positions for the purpose
of recording the movement of a subsequent train.
Fig. 7 represents another arrangement of the parts of the discs. When a
train passes, the rod h is lowered, which liberates the counterbalance m, and
thereby causes oscillation of the lever l, which bears on a pinn; this movement
produces a movement of rotation of the color discs until the arm o¹ fixed on the
centre comes in contact with a second bent lever p; these discs then coincide
with the openings a¹, a", of disc a, and indicate the closing of the line; the
discs subsequently return to their original position, as in the first arrangement
herein-before described.
Having described the nature of the Invention, and the manner of performing

page_text: the same, I declare that what I claim as the Invention to be protected by the
-herein-before in part recited Letters Patent is,
First, forming signal posts of parts combined as herein-before described,
and whereby a train effects automatically the signal indicating the state
of the line.
Secondly, the apparatus placed at a certain distance from the signal post
for the purpose of replacing the parts of the signal apparatus in their original
position by the action of the train, as herein-before described and represented
in the Drawings annexed.
In witness whereof, I, the said William Clark, have hereunto set my
hand and seal, this Seventh day of May, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witness,
W. G. E. SWINNOCK,
53, Chancery Lane, London.
W. CLARK. (L.S.)