IMPROVE- MENTS IN GUARD OR SAFETY SIGNALS FOR RAILWAY POINTS OR SWITCHES
Year: 1874

page_text: LETTERS PATENT to John Marchant, of No. 10, Dagmar Road,
Camberwell, in the County of Surrey, for the Invention of "IMPROVE-
MENTS IN GUARD OR SAFETY SIGNALS FOR RAILWAY POINTS OR SWITCHES."
Sealed the 17th April 1874, and dated the 2nd February 1874.
PROVISIONAL SPECIFICATION left by the said John Marchant at
the Office of the Commissioners of Patents, with his Petition, on
the 2nd February 1874.
I, JOHN MARCHANT, of No. 10, Dagmar Road, Camberwell, in the
County of Surrey, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN GUARD OR SAFETY SIGNALS FOR RAILWAY POINTS OR
SWITCHES," to be as follows:-
This Invention relates to means of signalling to a pointsman the
passage of a railway train over a set of points, which may be at a
distance from him and invisible to him, the object of such signalling
being to forbid his attempting to shift the points during the passage of a
train over them. For this purpose I mount by the side of the rail, close
to the point of the switch, a trigger or slide so arranged that any wheel

page_text: or its flange in passing over it shall depress it, a spring or counterweight
causing it to rise when the wheel is off it. To this slide or trigger I
attach an electric contact maker, and I connect the same by an
insulated wire to a battery and a signalling instrument in the signal box
or place where the pointsman is in attendance.
This signalling instrument may be of any known kind, either a needle
mounted in a coil, which is caused to oscillate by intermittent electric
currents, or it may have a polarized or spring armature acted on by an
electro-magnet, the movement of such needle or armature furnishing a
visible signal; or the armature may work a bell hammer so as to give an
audible signal, or both visible and audible signals may be given by the
use of any known electric signalling instrument. As the successive
wheels of a train pass over and depress the trigger or slide at the switch,
thereby making and breaking electrical contact, the signalling instru-
ment worked by the intermittent electric currents serves to inform the
pointsman that a train is passing the switch, and he will thus understand
that he should not move the point lever till such signalling has ceased.
When it ceases he will understand that the whole train has passed the
points, and that he may then with safety shift them.
In cases where there are many sets of points worked by levers in one
signal box, each set of points and its appropriate lever may be provided
with the signalling apparatus above described. Or, if preferred, there
may be only one such signalling apparatus, connected by wires with any
number or with all of the points, in which case the pointsman would
understand that he should not shift any of the points while a train is
passing any of them.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said John Marchant in the Great Seal Patent Office
on the 23rd July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN 3
MARCHANT, of No. 10, Dagmar Road, Camberwell, in the County of
Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her

page_text: of our Lord One thousand eight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Marchant, Her special
license, that I, the said John Marchant, my executors, administrators,
and assigns, or such others as I, the said John Marchant, 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 "IM-
PROVEMENTS IN Guard or Safety Signals For RAILWAY POINTS OR SWITCHES,"
upon the condition (amongst others) that I; the said John Marchant,
my executors or administrators, 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 immc-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Marchant, 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, reference being had to the accom-
panying Sheet of Drawings, and to the figures and letters marked
thereon, that is to say :-
This Invention relates to means of signalling to a pointsman the
passage of a railway train over a set of points, which may be at a
distance from him and invisible to him, the object of such signalling
being to forbid his attempting to shift the points during the passage of a
train over them. For this purpose I mount by the side of the rail, close
to the point of the switch, a trigger or slide so arranged that any wheel
or its flange in passing over it shall depress it, a spring or counterweight
causing it to rise when the wheel is off it. To this slide or trigger I
attach an electric contact maker, and I connect the same by an insulated
wire to a battery and a signalling instrument in the signal box or place
where the pointsman is in attendance.
This signalling instrument may be of any known kind, either a needle
mounted in a coil, which is caused to oscillate bv intermittent electric

page_text: currents, or it may have a polarized or spring armature acted on by an
electro-magnet, the movement of such needle or armature furnishing a
visible signal; or the armature may work a bell hammer so as to give an
audible signal, or both visible and audible signals may be given by the
use of any known electric signalling instrument. As the successive
wheels of a train pass over and depress the trigger or slide at the switch,
thereby making and breaking electrical contact, the signalling instru-
ment worked by the intermittent electric currents serves to inform the
pointsman that a train is passing the switch, and he will thus understand
that he should not move the point lever till such signalling has ceased.
When it ceases he will understand that the whole train has passed the
points, and that he may then with safety shift them.
In cases where there are many sets of points worked by levers in one
signal box, each set of points and its appropiate levers may be provided
with the signalling apparatus above described. Or if preferred there
may be only one such signalling apparatus, connected by wires with any
number or with all of the points, in which case the pointsman would
understand that he should not shift any of the points while a train is
nassing any of them

page_text: to the battery and signalling instrument in the signal box, which are
permanently in connection with earth or with the rails. One of the
springs is provided with an adjustable contact screw, which can be
brought to bear, as will hereafter be described, on the other spring, the
point of the screw and the face on which it is made to bear, being
platinised in the usual manner. An arm L secured to the head of the
trigger axis B, has a pin projecting from it which bears on the upper
of the two springs 8. When the wheel of a passing train depresses the
trigger A, its axis B being thereby partly turned causes the pin on the
arm L to press down the upper spring 8, thus bringing its screw point
in contact with the lower spring s¹. The battery and signalling instru-
ment at the signal box are thus brought into the electric circuit, and the
instrument is caused to give its visible or audible signal, which will be
repeated for every wheel that passes the trigger A, ceasing when the last
wheel of the train has passed.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I claim, the use of apparatus for
informing a pointsman that a train is passing over a set of points, in
which apparatus a trigger is arranged near the points with apparatus
for making and breaking electrical contact with a conductor connected
to a signalling instrument in the signal box, in such manner that the
signalling instrument is operated by the passage of wheels over the
trigger, substantially as herein described.
In witness whereof, I, the said John Marchant, have hereunto set
my hand and seal, this Twentieth day of July, in the year of
our Lord One thousand night hundred and sorrenty four