IMPROVEMENTS IN ELECTRICAL SIGNALLING AND INTERLOCKING APPARATUS FOR RAILWAYS
Year: 1883

page_text: LETTERS PATENT to Charles Hodgson of Canterbury Road Kilburn in the
County of Middlesex for an Invention of "IMPROVEMENTS IN ELECTRICAL
SIGNALLING AND INTERLOCKING APPARATUS FOR RAILWAYS
"
PROVISIONAL SPECIFICATION left by the said Charles Hodgson at the
Office of the Commissioners of Patents on the 6th June 1883.
CHARLES HODGSON of Canterbury Road Kilburn in the County of Middlesex,
"IMPROVEMENTS IN ELECTRICAL SIGNALLING AND INTERLOCKING APPARATUS FOR
RAILWAYS"
In the Specifications to Letters Patent granted to me on the 31* January 1877
N° 400, on the 4th April 1878 .N° 1326, on the 15th October 1879 No 4170, and on
the 2nd April 1871 N° 1453, I described means of interlocking the telegraphic
block signalling instruments used on railways with the point and signal levers at
the home and also at the distant stations, and in the Specification to Letters
Patent granted to J. S. Farmer and E. Tyer on the 10th July 1874 N° 2423, was
described apparatus whereby a signalling lever is rendered effective for lowering a
signal only while an electromagnet which forms part of the apparatus is subject
to an electric current transmitted from a distant station. My present invention
relates to means of rendering the ordinary needle telegraph instruments available
for interlocking with and controlling the point and signal levers, and to arrange-
ments for simplifying the operation of levers electrically controlled from a distance.
The needle telegraph instrument frequently employed on railways has a handle
by moving which to right or left an index needle is caused to move to right or left,
and it is by the succession and combination of these movements that signals
according to a predetermined code are transmitted. One of these signals "line
clear" is usually made by retaining the needle motionless in a particular attitude,
say deflected to the left, and, in order to retain it in this position for a time, the
signalling handle is fixed by inserting a pin through a hole in the casing and a
transverse hole in the spindle of the handle. I arrange near this spindle a contact
spring in such a position that the pin, when it is inserted, pushes the spring aside
so as to make an electrical contact, whereby a current is transmitted to give a
visible or an audible signal or to control the interlocking gear of the point and
signal levers at a distant station. The insertion of the pin is also made to raise a

page_text: detent lever which when raised, is caught and held up by a detent attached to the
armature of an electromagnet. On withdrawing the pin, a slide which had been
previously held open by the detent lever, is, by means of a weight or spring, moved
so as to cover the hole through which the pin is inserted, and thus renders it
impossible again to insert the pin while the detent lever is held up. The coil of
the electro-magnet is electrically connected to a distant contact which can be made
either by hand or automatically by the passage of a train over a treadle. On a
current being transmitted by making this contact, the detent is withdrawn, and
the detent lever falling, withdraws the slide so that the operator can again insert
the pin.
When it is desired to interlock the needle instrument with the point and signal
levers, I dispense with the pin, and connect to the signalling handle a notched rod.
I provide a hand lever which can be pushed down into a notch of the rod so as to
hold the signalling handle in the required position, and I connect this hand lever
to the interlocking gear of the point and signal levers in the manner described in
the Specification N° 400 of 1877. above referred to. I also arrange at the side of
the hand lever & contact spring, so that as the lever is depressed, an electrical
current is transmitted to the distant station; and provide a detent lever and
detent worked by the armature of an electromagnet so arranged that when the
hand lever is raised out of the notch, it is caught and held until an electrical
current transmitted from a contact made by hand or by the passage of a train over
a treadle, excites the electro-magnet and releases the detent.
In
When
I have mentioned above that the act of inserting the pin or depressing the hand
lever makes an electrical contact for transmission of a current to a distance.
many cases, this current may be applied to control a signal lever by means of
apparatus of the kind described in the Specification to Farmer and Tyer's Patent
No 2423 of 1874 above referred to. In one form of this apparatus described with
reference to Figs. 14, 15 and 16 of the drawings annexed to the said Specification,
a loaded lever is held in a nearly vertical position by the attraction of an electro-
magnet and while it is so held the signal can be worked. But when the attraction
ceases, the loaded lever falls and, withdrawing a catch, renders the hand lever
inoperative on the signal. In order to render the hand lever again effective, it is
necessary first to move it back, so as to raise the loaded lever, then to move it
forwards so as to engage the catch while the loaded lever is held up by attraction,
and then again to move it back to work the signal. I simplify this operation by
the following arrangement. I extend the spring catch rod of the hand lever so
that a stud on it projects immediately under the loaded lever, and I provide a
detent for the spring catch worked by the armature of an electromagnet.
the hand lever is in its normal position, its spring catch being engaged in a notch
of the quadrant in the usual way, before the lever can be moved, the spring catch
bas to be raised, but this can only be done when the detent is released by the
transmission of an electric current from a distance. When this is the case, the
raising of the spring catch has the effect, by means of the stud on its rod, of raising
the loaded lever sufficiently to permit engagement of the catch by which the hand
lever is connected to the signal pull. The hand lever being then moved back, the
signal is worked by it and at the same time the loaded lever is raised. When it is
raised a certain distance, a tumbler bearing against a stationary guide is pushed
aside, leaving the loaded lever free to fall unless it is held up by the attraction of
the magnet. When it is so held up, the hand lever remains operative on the
signal, but when the attraction ceases, the loaded lever falls and disengages the
catch, rendering the hand lever again inoperative on the signal. I am thus enabled
to dispense with the movement of the hand lever that was formerly required for
raising the loaded lever, by utilising the movement of the spring catch to effect
the engagement of the hand lever with the signal pull, and I govern this action
from a distance by subjecting the spring catch to the control of an electrical detent.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Hodgson in the Great Seal Patent Office on the
4th December 1883.
CHARLES HODGSON of Canterbury Road, Kilburn in the county of Middlesex
"IMPROVEMENTS IN ELECTRICAL SIGNALLING AND INTERLOCKING APPARATUS FOR
RAILWAYS
"
fof
J
"
In the Specifications to Letters Patent granted to me on, the 31st January 1877
No: 400, on the 4th April 1878 No: 1326, on the 15th October 1879 No: 4170, and
on the 2nd April 1871 No.: 1453, I described means of interlocking the telegraphic
block signalling instruments used on railways with the point and signal levers at
the home and also at the distant stations, and in the Specification to Letters Patent
granted to J. S. Farmer and E. Tyer on the 10th July 1874, No 2423, was described
apparatus whereby a signalling lever is rendered effective for lowering a signal
only while an electromagnet which forms part of the apparatus is subject to an
electric current transmitted from a distant station. My present invention relates
to means of rendering the ordinary needle telegraph instruments available for inter-
locking with and controlling the point and signal levers and to arrangements for
simplifying the operation of levers electrically controlled from a distance.
The needle telegraph instrument frequently employed on railways has a handle,
by moving which to right or left, an index needle is caused to move to right or
left, and it is by the succession and combination of these movements that signals,
according to a predetermined code, are transmitted. One of these signals, "line
clear," is usually made by retaining the needle motionless in a particular attitude,
say deflected to the right, and, in order to retain it in this position for a time, the
signalling handle is fixed by inserting a pin through a hole in the casing and a
transverse hole in the spindle of the handle.. I arrange near this spindle a contact
spring in such a position that the pin, when it is inserted, pushes the spring aside,
so as to make an electrical contact, whereby a current is transmitted to give a
visible or. an audible signal, or to control the interlocking gear of the point and
signal levers at a distant station. The insertion of the pin is also made to raise a
detent lever, which, when raised, is caught and held up by a detent attached to the
armature of an electromagnet. On withdrawing the pin, a slide, which had been
previously held open by the detent lever, is, by means of a weight or spring, moved
so as to cover the hole through which the pin is inserted, and thus renders it
impossible again to insert the pin while the detent lever is held up. The coil of
the electro-magnet is electrically connected to a distant contact, which can be made
either by hand or automatically by the passage of a train over a treadle. On a
current being transmitted by making this contact, the detent is withdrawn, and
the detent lever falling, withdraws the slide so that the operator can again insert
the pin.
When it is desired to interlock the needle instrument with the point and signal
levers, I dispense with the pin, and connect to the signalling handle a notched rod.
I provide a hand lever which can be pushed down into a notch of the rod, so as to
hold the signalling handle in the required position, and I connect this hand lever
to the interlocking gear of the point and signal levers in the manner described in
the specification No: 400 of 1877, above referred to. I also arrange at the side of
the band lever a contact spring, so that as the lever is depressed, an electrical
current is transmitted to the distant station; and I provide a detent lever, and
detent worked by the armature of an electromagnet, so arranged that when the
hand lever is raised' out of the notch, it is caught and held until an electrical

page_text: current transmitted from a contact, made by hand or by the passage of a train over
a treadle, excites the electromagnet and releases the detent.
ment.
as to
I have mentioned above that the act of inserting the pin or depressing the hand
lever makes an electrical contact for transmission of a current to a distance. In
many cases, this current may be applied to control a signal lever by means of
apparatus of the kind described in the specification to Farmer and Tyer's patent
No 2423 of 1874 above referred to. In one form of this apparatus, described
with reference to figs 14, 15 and 16 of the drawings annexed to the said
Specification, a loaded lever is held in a nearly vertical. position by the attrac-
tion of an electromagnet, and while it is so held, the signal can be worked.
But when the attraction ceases, the loaded lever falls, and, withdrawing a
catch, renders the hand lever inoperative on the signal. In order to render
the hand lever again effective, it is necessary first to move it back, so
raise the loaded lever, then to move it forwards so as to engage the catch
while the loaded lever is held up by attraction, and then again to move it
back to work the signal. I simplify this operation by the following arrange-
extend the spring catch rod of the hand lever so that a stud on
it projects immediately under the loaded lever, and I provide a detent for
the spring catch worked by the armature of an electromagnet.. When the
band lever is in its normal position, its spring catch being engaged in a notch
of the quadrant in the usual way, before the lever can be moved, the spring
catch has to be raised, but this can only be done when the detent is released by
the transmission of an electric current. from a distance. When this is the case,
the raising of the spring catch has the effect, by means of the stud on its rod, of
raising the loaded lever sufficiently to permit engagement of the catch by which
the hand lever is connected to the signal pull. The hand lever being then moved
back, the signal is worked by it, and at the same time, the loaded lever is raised.
When it is raised a certain distance a tumbler bearing against a stationary guide
is pushed aside leaving the loaded lever free to fall, unless it is held up by the
attraction of the magnet. When it is so held up, the hand lever remains
operative on the signal, but when the attraction ceases, the loaded lever falls
and disengages the catch, rendering the hand lever again inoperative on the
signal. I am thus enabled to dispense with the movement of the hand lever
that was formerly required for raising the loaded lever, by utilising the
movement of the spring catch to effect the engagement of the hand lever with
the signal pull, and I govern this action from a distance by subjecting the
spring catch to the control of an electrical detent.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a front view a fig 2 a side view, with parts of the casing removed to
shew the interior, of an ordinary needle telegraph block signalling instrument with
electrical interlocking appliances according to my invention. A is the spindle of
the signalling instrument which is worked by the handle B, and C is the pin which
is inserted in the oblique transverse hole of the spindle A to hold it in position
when required for signalling "line clear." D is a contact spring which is acted on
by the insertion of the pin C, so as to make electrical contact, by which a current
is transmitted to a distant station, so as to unlock such of the apparatus there as
was properly locked before the "line clear" signal was transmitted.
On withdrawing the pin C for the purpose of using the instrument for signalling
generally, the contact made by D is broken, so that there is no longer any current
to effect unlocking. The insertion of the pin C also moves a lever E raising its
heavy end, on which is a catch e that becomes engaged with a detent hook fon
the arm of the armature lever F. On the lever E, there is a stud e' which
takes into a slot in a vertically sliding plate G that is linked to a lever H,
counter-weighted sufficiently to raise the plate G, when it is free. The
plate G has through it a hole, which in its lower position, coincides with
"

page_text: the hole in A, when it is presented for the insertion of the pin C. By inserting
the pin, the plate is held by the pin passing through its hole, but the stud e' is
raised to the upper end of the slot in G. On withdrawing the pin C, the weight
of the lever H causes the plate G to ascend, so that it no longer presents a hole for
the insertion of the pin C, and consequently the pin cannot be inserted, while the
plate G remains in its raised position. On the transmission of an electric current
from another station, or by a contact being made by the passage of a train over a
treadle on the line, the electro-magnet M is excited and attracts its armature F,
releasing the catch e from the hook f. Thereupon the lever E descends by its
weight, and, by means of the stud e', draws down the sliding plate G, and holds it
down with its hole in proper position for the insertion of the pin C.
Fig. 3 is a front view and fig. 4 a side view shewing the modified arrangement
in which a hand lever K is employed instead of the pin C described above, to
hold the signalling handle B by being moved down behind a shoulder b on a
rod B' which is linked to the handle B. The lever K has on its side a stud k;
which is immediately under a stud 1, projecting from the side of a heavy ended
lever L, on which is another stud ¹, taking into a slot of a rod n, linked
to a detent lever N. A catch stud also projects from the lever L to
be engaged when it is raised by the book fon the armature lever F.
The handlever K is linked by the rod O to the interlocking gear. On
moving the signalling handle B to signal "line clear," the hand lever K
is pushed down behind the shoulder b, this movement, by means of the rod O,
acting on the interlocking gear of the point and signal levers. The depression of K
also, by means of the studs k and 1, raises the heavy end of the lever L, so that 7
becomes engaged by f, which holds the lever up. This movement also, by the
descent of in the slot of n allows the detent lever N to fall towards the position
shewn dotted in fig. 4.
The hand lever K can now be raised only half-way, a
horn K¹ upon it being caught in a recess of the detent lever N, and thus holds the
lever K in its middle position, so that it cannot be moved either way, and the
interlocking, which had been effected by the movement of O, cannot now be
altered. When, however, an electric current is transmitted from another station or
by passage of a train over a treadle, the magnet M attracts is armature, releasing l³
from, and the lever L descends raising the detent lever N, and so leaving the
hand lever K free to be moved. Contact springs are arranged by the side of K,
so that the pushing down of K makes contact for transmission of a current in a
manner similar to that above described as being effected by the insertion of the
pin C.
Fig. 5 is a side view and fig. 6 a front view of apparatus according to my inven-
tion for actuating, by means of the spring catch, the apparatus described in the
Specification No: 2423 of 1874 above referred to. Figs. 7 and 8 are side views
shewing the apparatus in two positions different from that shewn in fig. 5. A. is
the ordinary signalling lever, having its spring catch rod a. I attach to the rod a
a latch hook a¹, which is engaged by an arm on a rocking shaft B having on it a
toothed segment arm b, into the notch of which drops the armature lever m of an
electromagnet M. When m is in the notch of the segment b, the spring catch rod a
cannot be raised out of the notch in the ordinary quadrant, and, consequently, the
main lever A. cannot be moved; but when the inagnet M is excited by a current
transmitted from another station or by passage of a train over a contact treadle,
the lever m is held out of the notch of b, and then the rod a can be raised,
permitting the lever A to be moved. I link to an arm of the shaft B, a rod C,
which extends down through a guide in the framing, and has on its side a stud c
which projects immediately under one arm of a bell crank D, on the other arm of
which is mounted a roller d. The bell crank D is mounted on a radius E which is
linked by a forked rod e (shewn in front view at fig. 9) to the the arm of the
lever A. On the same pivot as the radius E, is mounted another radius F, to which
is attached the signal pull f. On the radius E is pivotted a catch hook G which is
kept disengaged from F by the pressure on it of the weighted lever H as shewn in

page_text: fig: 5, but which engages was shown in figs. 7 and 8, when the weighted
lever Hist raised On the weighted lever H is a bevilled stud h, and on the
framing are two projecting curved guides k, between which the roller d travels
during part of its upward course. N is the magnet which holds by attraction the
weighted lever H when it is raised, and O is a contact slide which is made to
complete the circuit for the magnet N as the weight H approaches the magnet.
The operation of the apparatus is as follows. The spring catch rod a, if left free
to be raised by the action of the magnet M, on being raised, lifts the rod C and
this, by means of its stud c, raises the bell crank D, bringing its roller d under the
stud h and so raising H sufficiently to relieve the hook G which thereupon engages
with F. On now moving the lever A to the right, the two radii E and F are raised
together, and the signal pull f is drawn. Also the bell crank D rises with E, and
its roller, travelling between the guides k and under h raises the weighted lever H
until it comes up to the magnet N, making contact by means of O just before it
reaches N. The roller d, having raised h until it has attained the position
shewn in fig. 8, escapes from the guides k leaving H sustained by the attraction
of N. In this condition of the apparatus, the signal can be altered by moving
back the lever A, or when, by breach of contact at a distant station, the current
which excites N is made to cease, the weighted lever H descends, striking the tail
of the hook G, and so releasing F, which descends, slackening the pull f, and so
putting the signal to "danger."
Having thus described the nature of my invention and in what manner the same
is to be performed, I claim :-
First In a telegraphic block signalling instrument, in combination with the pin C
employed for holding the signalling handle, the contact D and the detent apparatus
actuating the sliding plate G, substantially as and for the purposes set forth with
reference to figs 1 and 2.
• Second: In a telegraphic block signalling instrument, in combination with the
signalling handle, the stop lever K, connected to the interlocking gear and its
detent apparatus and contact D, substantially as described with reference to
figs. 3 and 4.
Third: In apparatus of the kind described in Farmer and Tyer's Specification
No: 2423 of 1874, effecting the engagement of the signal lever with the signal
pull by movement of the spring catch rod, when the said rod is released by the
action of an electrical current, substantially as herein described with reference to
figs. 5, 6, 7, 8 and 9.
In Witness whereof I the said Charles Hodgson have hereunto set my hand and
seal this Third day of December in the year of our Lord one thousand' eight
hundred and eighty-three.
ATT TEDA
ANITAT HΠΑ
(L.S.)