Improvements in Apparatus for Ensuring Safety on Single Lines of Railway.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Ensuring Safety on Single Lines of
Railway.
I, EDWARD TYER, of Ashwin Street, Dalston, in the County of London,
Engineer, do hereby declare the nature of this invention to be as follows:-
In my previous Specifications No. 1262 of 1878, No. 42 of 1888, No. 5928
of 1890, No. 1904 of 1891 No. 18603 of 1891, No. 2798 of 1892, No. 12144 of
1893, No. 14001 of 1894 and No. 21831 of 1895, I have described apparatus for
ensuring safety of traffic on single lines of railway by electrically controlling
the issue from a station of a tablet or staff to be carried by a train to a station
beyond, thus providing against the admission of more than one train to the
section of the line extending between the connected stations. Usually the
apparatus and electrical connections are so arranged that no release of the
apparatus to allow of the issue of a tablet or staff can take place until the train
carrying the tablet or staff already issued reaches the distant station.
My present invention relates to a simplified and more effective construction
of apparatus for this purpose, and to its modification in such a manner that a
number of tablets can be successively issued for trains running in the one
direction. The apparatus, when it is not so modified, but employed only for
what may be termed absolute working, comprises a closed casing having
within it a receptacle for tablets and a couple of electromagnets with their
armatures arranged to operate as catches for a horizontal slide, in which there
is a recess to receive a tablet, and on which there are contacts for effecting
commutation of the electric circuits. At the top of the casing there is an open-
ing through which a tablet can be introduced, the passage by which the tablet
descends into the receptacle being furnished with a counterpoised lever which
is moved by the tablet as it passes, and operates on one of the catches for the
slide. In the front of the casing there is an opening through which can be
seen the usual visible signals of "section clear" "train approaching"
""train on
line," these signals being shewn on screens behind the opening moved by the
slide when it is partially, or fully withdrawn or pushed home.
These parts are so arranged that "absolute" working is carried on as follows:-
A and B being the stations at the ends of a section of the line, each provided
with a tablet apparatus, when A wishes to send a train towards B he signals to B
for permission to withdraw a tablet from his receptacle. When B signals his
assent, A holds down his plunger key thus transmitting an electric current to one
of the electromagnets in B's apparatus. This by releasing one of the catches
permits B to draw his slide about half way, not enough to allow withdrawal of
a tablet, but this by moving the contacts on the slide reverses the direction of
current, so that B can now send a current which acts on the electromagnets in A's
apparatus so as to release the slide and allow him to withdraw a tablet. Having
done so, the slides of both A's and B's apparatus remain locked, so that they
cannot be moved, and no tablets can be withdrawn at either station while the
train is on its way with the tablet that had been issued by A. When the train
arrives at B, the tablet is introduced into B's receptacle and in its passage it.
unlocks the slide so that B can push it in. Having done so he signals to A

page_text: that the "section is clear," whereupon A pushes in his slide and both apparatus
are then in condition for operating again when either A or B has to issue a tablet.
In some cases a tablet is required for shunting purposes at either station, as
for instance at A. In that case A, with leave from B, withdraws a tablet which
is employed for unlocking sidings; and, when the shunting is over A introduces
the tablet into his apparatus pushes home his slide, and signals to B that he has
done so, whereupon B pushes home his slide which had been partly withdrawn
and then both apparatus are restored to normal condition.
86
When the conditions of the line are such as to require what may be termed
permissive" working that is to say, the issue of a number of tablets successively
from either station, the apparatus above described, which may be termed the
primary" apparatus has combined with it a "secondary apparatus, com-
prising a receptacle for tablets and a slide which are most conveniently situated
above the "primary" apparatus. "Permissive" working with the combined
56
apparatus is carried on as follows:-
"
When A desires to issue successive tablets, he signals to B, who, by means of a
key, puts his apparatus in condition for "permissive" working and withdraws a
catch slide which opens the bottom of his secondary receptacle.
He then per-
mits withdrawal of a tablet from A's apparatus, and this having been done, his
key cannot be withdrawn.
When A has sent a train with the first tablet, he can again signal to B for
permission to issue a second tablet. Thereupon B by pushing the slide of his
secondary apparatus, transfers a tablet from his secondary to his primary recep-
tacle, and by this operation unlocks his primary slide which he withdraws about
half-way and then he permits A to withdraw a second tablet. In like manner A
can be permitted to withdraw a number of successive tablets. Each tablet on
reaching B is inserted into the secondary receptacle, there being no means of
introducing it into the primary receptacle, and, as the number of tablets arriving
from A must correspond with the number transferred from the secondary to the
primary receptacle at B, for a tablet has to be so transferred in giving permission
to A in each case, the tablets in the secondary receptacle at B can only amount
to their original number when all the tablets sent from A have been introduced
into B's secondary receptacle.
When the receptacle is thus filled a catch is acted on allowing B to withdraw
his key and thus restore his apparatus to the condition for "absolute" working.
Although I have described the working both "absolute" and
"
permissive"
as consisting in the issue of tablets from A it is to be understood that the working
in issuing from B is in every respect similar.
Dated this 5th day of November 1898.
ABEL & IMRAY,
Agents for the Applicant.
Improvements in Apparatus for Ensuring Safety on Single Lines of
Railway.
I, EDWARD TYER, of Ashwin Street, Dalston, in the County of London,
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:
-
In my previous Specifications No. 1262 of 1878, No. 42 of 1888, No. 5928
of 1890, No. 1904 of 1891 No. 18603 of 1891, No. 2798 of 1892, No. 12144 of
1893, No. 14001 of 1894 and No. 21831 of 1895, I have described apparatus for

page_text: ensuring safety of traffic on single lines of railway by electrically controlling
the issue from a station of a tablet or staff to be carried by a train to a station
beyond, thus providing against the admission of more than one train to the
section of the line extending between the connected stations. Usually the
apparatus and electrical connections are so arranged that no release of the
apparatus to allow of the issue of a tablet or staff can take place until the train
carrying the tablet or staff already issued reaches the distant station.
My present invention relates to a simplified and more effective construction
of apparatus for this purpose, and to its modification in such a manner that a
number of tablets can be successively issued for trains running in the one
direction. The apparatus, when it is not so modified, but employed only for
what may be termed absolute" working, comprises a closed casing having
within it a receptacle for tablets and a couple of electromagnets with their
armatures arranged to operate as catches for a horizontal slide, in which there
is a recess to receive a tablet, and on which there are contacts for effecting
commutation of the electric circuits. At the top of the casing there is an open-
ing through which a tablet can be introduced, the passage by which the tablet
descends into the receptacle being furnished with a counterpoised lever which
is moved by the tablet as it passes, and operates on one of the catches for the
slide. In the front of the casing there is an opening through which can be
seen the usual visible signals of "section clear" "train approaching"
"train on
line," these signals being shewn on the face of a segment behind the opening,
which segment is moved by the slide, when it is partially or fully withdrawn
or pushed home.
When the conditions of the line are such as to require what may be termed
"permissive" working, that is to say, the issue of a number of tablets successively
from either station, the apparatus above described, which may be termed the
primary" apparatus has combined with it a secondary" apparatus, com-
prising a receptacle for tablets and a slide which are most conveniently situated
above the primary apparatus.
"
"
I shall describe the combined tablet apparatus for permissive working referring
to the accompanying drawings, as the apparatus by excluding the use of the
upper part can be employed for absolute working.
Fig. 1 is a side view, the sides of the casing being removed to shew the interior.
Fig. 2 is a plan of the operative part of the lower, which is the primary
apparatus. Figs. 3, 4 and 5 are partial longitudinal sections on the lines A-A,
B-B, and C-C of Fig. 2 respectively.
Figs. 6 and 7 are transverse sections on the line D-D of Fig. 1 shewing the
upper receptacle in two conditions not filled in Fig. 6, and quite filled with tablets
in Fig. 7. A perspective view of the apparatus as it is made for absolute working
only is shewn by Fig. 8.
The
In this apparatus as in those described in former specifications there is a recep-
tacle a containing superposed tablets, and under it a slide 6 having in it a recess
the depth of a tablet so that where the slide is drawn out the lowest of the
tablets is brought from the receptacle and can be taken from the recess. There
is also a secondary receptacle c above with a slide d under it, this receptacle being
used only when the apparatus is employed for permissive working. For absolute
working the bottom of the receptacle is closed by a transverse slide e.
slide has certain notches and slots to receive two pawls f and g each of which
can be raised from engagement with the slide by an electromagnet when it is
energised, attracting its armature which acts on the pawl. The slide also has
fixed on it a block carrying three contact pieces which slide under two pairs of
springs thus constituting a commutator which changes the direction of the
electric current transmitted from station to station, the current having onc
direction when the slide is fully in, and having the opposite direction when the
slide is about half drawn out, or fully out according as the contact pieces come
under the springs.

page_text: The operation for absolute working is as follows
A and B being the stations at the ends of a section of the line, each provided
with a tablet apparatus when A wishes to send a train towards B he signals to B
for permission to withdraw a tablet from his receptacle. When B signals his
assent, A holds down his plunger key n thus transmitting an electric current to
the electromagnet in B's apparatus the armature of which by releasing the catch g
permits B to draw his slide outwards but only about half way it being stopped by
the pawlf so that it is not far enough out to allow withdrawal of a tablet, but
this by moving the contacts h reverses the direction of current, so that B can
now by his plunger key n send a current which acts through a polarised relay
energising the electromagnet in A's apparatus so as to raise the pawl f the tail
of which acting on a pin on raises g and thus releases the slide and allows A
to withdraw a tablet. Having done so, the slides of both A's and B's apparatus
remain locked by the pawls so that they cannot be moved, and no tablets can be
withdrawn at either station while the train is on its way with the tablet that
had been issued by A. When the train arrives at B, the tablet is introduced
into the recess of B's upper slide d which is pushed in and the tablet descends
a sloping shoot i into B's receptacle a. In its passage it depresses a pivotted
plate raising a rod k and thereby raising and releasing the pawl g
thus unlocking the slide so that B can push it in. Having done so, he sig
nals to A that the section is clear, whereupon A pushes his plunger key n
thereby unlocking his slide which he pushes in, and both apparatus are then
in condition for operating again when either A or B has to issue a tablet.
In some cases a tablet is required for shunting purposes at either station, as
for instance at A. In that case A, with leave from B, withdraws as above de-
scribed a tablet, which is employed for unlocking sidings, and, when the shunt-
ing is over. A introduces the tablet into his apparatus, pushes home his slide and
signals to B that he has done so, whereupon B pushes home his slide which had
been partly withdrawn and then both apparatus are restored to normal condition.
Permissive working with the combined apparatus is carried on as follows:
When A desires to issue successive tablets he signals to B the number of trains he
is going to send, and B by means of a key acting in a lock 7 moves a sliding rod v
to the position shewn in Fig. 1, having thus moved two bell cranks w¹² which
withdraw two pins the one w³ from under the pawl y allowing it to drop and
form a stop for the slide d, the other w from a hole in the cross slide e allowing
it to be withdrawn. When the apparatus is in this condition for permissive
working, B permits withdrawal of a tablet from A's apparatus, and this having
been done he withdraws the transverse slide e opening the bottom of his secondary
receptacle c.
When A has sent a train with the first tablet. he can again signal to B for
permission to issue a second tablet, and by means of a knob o he sends a current to
an electro-magnet p in B's apparatus by which a pawl q is raised releasing B's
slide d.
Thereupon B, by pushing in the slide d of his secondary apparatus transfers
a tablet from his secondary receptacle c to his primary receptacle a and by
this operation he lowers by one the pile of tablets in c, whereupon a rod m
descends and acts as a stop to the bolt worked by the lock 2, which then cannot
be unlocked nor can the key be withdrawn.
The descent of the tablet unlocks B's primary slide which he pushes home
and then he permits A as previously described to withdraw a second tablet. In
like manner A can be permitted to withdraw a number of successive tablets.
Each tablet on reaching B is inserted into his secondary receptacle c there being
no means of introducing it into the primary receptacle, and, as the number of
tablets arriving from A must correspond with the number transferred from the
secondary to the primary receptacle of B. for a tablet has to be so transferred
in giving permission to A in each case, the tablets in the secondary receptacle

page_text: at B can only amount to their original number when all the tablets sent from A
have been introduced into B's secondary receptacle.
In order that B may be able to insert a tablet as described he must first pull
out his slide d. To enable him to do so he first, by means of an external handle
raises a levert the end of which, passing up through a slot in the slide d, pushes
up the tablets in c and also by a bar a projecting from its side moves a lever,
so as to withdraw a pawl u from a notch of the slide d. B can then withdraw
his slide d with its recess empty ready to receive a tablet. A counter-weighted
pawl y, by entering a recess in the slide d prevents the slide from being pulled
too far out. When, by the introduction of successive tablets by means of the
slide d, the receptacle c is quite filled and the transverse slide e is pushed in,
the rod m is then raised, allowing B to turn the key backwards and withdraw it,
thus restoring his apparatus to condition for absolute working.
This, however, cannot be done without also raising the lever t, as a pro-
jection from the sliding rod is stopped by the bar a projecting from the side
of the lever t; consequently, the rod cannot be moved by the key unless the
lever t is raised sufficiently high for a to be clear of v¹. This cannot be done
when the slide d is in such a position that it does not present the slot through
which the end of t has to rise, or, even if the slide d is in proper position, the
receptacle e may have too many tablets in it, so that the lever m¹ is up against
the stop m², then also the lever t cannot be raised sufficiently.
In the latter case B must first push the lowest tablet onwards by the slide d
till it drops into the shoot i.
"
Although I have described the working both "absolute" and " permissive
as consisting in the issue of tablets from A, it is to be understood that the
working in issuing from B is in every respect similar.
By the several movements of the slide 6 acting by incline r on a roller carried
by one arm of a bell crank lever s, the other arm which is in the form of a
cylindrical segment is made to take three different positions presenting through
"line closed," train
an opening of the casing three different indications such as
on line," and "train approaching."
37 66
When the apparatus is to be intended for absolute working only, the upper
receptacle c slide e with its lever and rod m, the magnet p and the lock land
the parts worked by it are dispensed with, as shewn in Fig. 8.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is:-
1. Apparatus for controlling issue of tablets for traffic on single lines of rail-
way, comprising a receptacle for tablets, a recessed slide, pawls engaging with
notches and slots of the slide, electromagnets operating the pawls, an upper slide
and inclined shoot for introducing tablets and a balanced lever at the head of the
shoot connected to one of the slide pawls, all arranged and operating for absoluto
working, substantially as described with reference to the drawings.
2. In combination with the apparatus above referred to, an upper receptacle
for tablets with transverse slide and an upper electromagnet controlling the
upper slide, arranged and operating for permissive working substantially as
described, with reference to the drawings.
Dated this 2nd day of August. 1899.