IMPROVEMENTS IN RAILWAY ELECTRICAL SIGNAT Annina
Year: 1865

page_text: LETTERS PATENT to William Henry Precce, of the Town and County of
Southampton, Civil Engineer, for the Invention of "IMPROVEMENTS IN
RAILWAY ELECTRICAL SIGNAT Annina"
PROVISIONAL SPECIFICATION left by the said William Henry Preece
at the Office of the Commissioners of Patents, with bis Petition, on the
3rd August 1865.
I, WILLIAM HENRY PREECE, of the Town and County of Southampton,
Civil Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN RAILWAY ELECTRICAL SIGNAL APPARATUS," to be as follows.―
The object of this Invention is to prevent the possibility of a signalman
signalling that the line is clear until the train which should control his move-
ments has actually passed his box; to this end I apply to the switch of railway
signal telegraph apparatus a means of locking the switch bandle or lever after
it has been used to adjust a signal, and of retaining it in a fixed position until
released by the action of a passing train, which will remove the cause for
retaining, say, the danger signal, in a fixed position The switch lever, as it
is moved gives a locking motion to a crank lever fitted with a spring catch;
this sping catcb, in one direction of its motion strikes a pin on a sliding bar,

page_text: and drives that bar forward, but on its return motion the spring catch slides
over the pin. Affixed to this sliding bar is a plate, which as the bar is slidden
forward enters a notch in the end of the switch lever and locks that lever.
Pendent from the switch box is an arm which is vibrated by any convenient
lever arrangement set in action by the passing of a train or engine over a
raised stop connected with that level arrangement. This vibrating arm when
moved stakes a second pin or projection on the sliding bar before mentioned
and forces it back, together with the locking plate, which leaves the switch
lever free to be moved by the signalman
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Henry Preece in the Great Seal Patent Office
the 3rd February 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENRY PREECE, of the Town and County of Southampton, Civil Engineer,
send greeting.
WHEREAS Der most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of August, in the year of our Loid
One thousand eight hundred and sixty-five, in the twenty-ninth year of
Her reign, did for Herself. Her heirs and successors, give and grant unto me,
the said William Henry Precce, Ici special licence that I, the said William
Henry Piecce, my executors, administrators, and assigns, or such others as I,
the said William Heniy Piecce, 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 RAILWAY ELECTRICAL SIGNAL APPARATUS," upon the condi-
tion (amongst others) that I, the said William Henry Preece, my executors
or administrators, by an instrument in writing under my, or their, or one of
then 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 inmediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Willham Deny Preece, do hereby
declare the nature of my said Invention, and in what manner the same is to
performed, to be particularly described and ascertained in and by the following

page_text: statement, reference being had to the Drawing hereunto annexed, and to the
letters and figures marked thereon (that is to say):
--
The object of this Invention is to remove the possibility of a signalman
signalling by inadvertence or mistake that the line is clear before the train
which should control bis movements has actually passed his box; this end I
obtain by the use of the switch lever apparatus shewn in the accompanying
Drawing for working the electric signal apparatus at a distant station.
Fig. 1 is a bach view of the apparatus; Fig. 2 an inverted plan view,
and Fig. 3 a vertical section taken in the line 1, 2, of Fig. 2. This switch
lever apparatus I connect (as shewn at A, Fig. 4) with the railway by any
suitable arrangement of levers and rods or trackers which are set in action by
the passing train for the purpose of withdiawing a restraining bolt applied to
the handle or lever of the switch apparatus, and thereby leaving it fiee to be
set in action by the signalman.
a is the handle or lever of the switch apparatus mounted on a centre at b,
the bearing for which is insulated by being let into a table of wood c. Fitted
to opposite sides of the switch handle are the spring clips a¹, a', which aro
intended to embrace the divided bridge or insulated segment plates d, d¹,
connected by clamping nuts e, e¹, to electric wires leading to the terminals e³, e³,
The switch lever is also in metallic contact with a wire leading to the
terminal. A pin a³ at the lower end of the switch lever a projects into the
forked end of a bell-crank lever f, mounted on the under side of the table, and
fitted at its opposite end with a spring catch or tumbler f As this switch lever
a is moved it will give a rocking motion to the bell crank lever for the pur-
pose to be presently explained. The lower part of the switch lever has a
notch cut in its edge to receive a sliding bolt g by which it is locked in its
normal position; this bolt is carried by a slotted guide bar g', through the
slots of which screws are passed for securing it to brackets attached to the
under side of the table. This guide bai is provided on its face with a pin g²,
against which the spring catch fis intended to strike in one direction of its
motion for the purpose of driving that bat forward, but on its return motion
the spring catch slides over the pin Upon the edge of the guide bai is a
second pin or projection g³ through which the bar receives an endway motion
in the opposite direction to that imparted by the bell crank. This pin g³ 15
acted upon by a pendent lever h, which is itself acted upon by a vertical rock
lever 2, Fig. 4, connected at its lower end to a sliding 1od k, this rod k
s caused to bear against a horizontal level or switch applied to the railway
track, as shewn at Fig 4, and in plan view at Fig. 5, a spring m or a weight
being used to keep the rod up to its bearing. Supposing now a train to be

page_text: passing along a line fitted with the locking apparatus above described in the
direction of the arrow, Fig 5, the switch or lever will by the lateral pressure
it will receive from the flange wheels passing between it and the fixed rail be
1ocked, and it will thus give an endway motion to the rod or tracker k, which
will in its turn rock the levers 2 and h, and the latter striking against the pin
on the bai g will drive it and the bolt which it carries into the dotted position
of Fig 2. The switch lever will therefore be free to be moved from the
drawn to the dotted position of Fig 3 for the purpose of operating a
Jistant signal.
As this apparatus is specially adapted for use with my improved block
signal telegraph apparatus in which the semaphore arm is maintained by a
weight and depressed by the action of the electric current I apply it in the
following manner, viz, the terminal e I connect with the earth, the
terminale with the battery, and the terminal e' with the line wire. When
therefore the and lever is in the drawn position of Fig. 3, which is its
normal position, there is no current passing through the distant signal
apparatus which the switch apparatus is intended to control, and the block
signal is consequently up; on the other hand, when the hand lever is in the
dotted position the current will pass through the distant signal apparatus and
retain the semaphore arm at the depressed position, thereby indicating "line
open."
If now the signalman at the distant station A signals to the man at
station B that a train has started from A in the direction of station B, the
duty of the receiver of this signal will be immediately to raise the block signal
at station A, this he will do by throwing over the switch lever B into the
drawn position, but in the act of doing this he will cause the bell-crank lever f
to strike the ping on the sliding bar g', and throw the bolt into the notch
of the switch lever, the lever will therefore remain fixed, and be beyond
the control of the signalman at station B As soon, however, as the advanc-
ing train passes the switch or lever 1, and sets the rod k and lever 1, h, in
motion as above explained, the guide bar g' and bolt g will be returned to the
dotted position of Fig. 2, and the signalman will then be able to set his switch
apparatus in action. If, however, he should delay in communicating the
proper signal to station A that the line is open no casualty can arise, the only
inconvenience being the undue blocking of the line.
I would remark that I do not confine myself to the means shewn of trans-
mitting the requisite motion from the passing train to the sliding bolt as
I proposed to use any approved arrangement, but I have described that
which I consider the most efficient for the purpose, neither do I limit the
use of my Invention to the operating of signal apparatus of the kind referre:]

page_text: to, but I design to use it in conjunction with any system of railway electric
signal apparatus to which it may be beneficially adapted.
Having now set forth the nature of my Invention of "Improvements in
Railway Electric Signal Apparatus," and explained the manner of carrying
the same into effect, I wish it to be understood that under the above in part
recited Letters Patent I claim, locking and releasing the switch lever in the
manner and for the purpose above descubed
In witness whereof, I, the said William Henry Preece, have hereunto
set my hand and seal, the Second day of February, in the year
of our Lord One thousand eight hundred and sixty-six.
W. II. PREECE. (L.S.)