An Improvement in Railway Signal Interlocking Apparatus.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
An Improvement in Railway Signal Interlocking Apparatus.
I, CHARLES HODGSON, of Canterbury Road, Kilburn, in the County of London,
Engineer, do hereby declare the nature of this invention to be as follows:-
It is often necessary to provide at a railway station means of interlocking one
signal, such for instance as a distant signal with other signals in such a manner
that the distant signal cannot be put to safety' " unless one or other of the
other signals are first put to "safety." This is usually effected by suitable inter-
locking of the levers by which the signal pulls are actuated, but it may happen,
especially when the pulls extend over considerable distances, 'that, owing to
accident, looseness due to expansion, or to other causes the interlocking fails and
that the distant signal is put to "safety" when it ought to remain at "danger."
My invention relates to an apparatus applicable to the signal pulls at any con-
venient part of their length which constitutes an indepedent interlocking
ensuring that the distant signal shall not be put to "safety" unless one or other
of the signals interlocked with it is first put to "safety," this apparatus pro-
viding also for expansion and contraction of the distant signal pull."
I shall describe apparatus according to my invention referring to the accom-
panying drawings.
Fig. is a side view and Fig. 2 is a plan. On a base A firmly fixed on the
ground at some place intermediate between the distant signal that is to be con-
trolled and the other signals which control it, is pivotted a 3 armed lever one
arm B of which has attached to it a pull W₁ from one of the controlling levers
or several of these, these pulls being kept tight by a weight on another of the
arms B, whilst the third arm B3 has at its end a pin projecting under a lever C.
This lever which extends through a guide 0 and is pivotted on the axis of a
pulley D, has a downwardly proiecting tooth C. A sliding bar E has attached
to its one end a pull W2 from the lever which should work the distant signal,
its other end has attached to it a chain passing over a pulley F to a weight F
The bar E has a lateral projection E which extends upwards as a tooth. On
the base A is pivotted a lever, one arm G¹ of which lies immediately under the
lever C its other arm G2 being formed as a downwardly projecting tooth. The
pulley D has on its axis on each side of it a roller D¹ and Ds free to run along
tracks A1, A2, formed on the base A.
Over the pulley passes a chain loaded by a weight F2 and attached to the
pull W³ for the distant signal.
The apparatus operates as follows:-
When the parts are in the position shewn the pull W2 for the distant signal
cannot have any effect on the signal because the bar E to which it is attached is
stopped by its tooth El meeting the tooth G2 and because the tooth C³ is clear
above the tooth E¹ and therefore, even if G2 were absent. the lever C would not
be moved. When however any one of the pulls W is drawn by the movement
to "safety" of the signal to which it is connected then the arm B³, being lowered
the lever C descends bringing its tooth C³, in front of the tooth E¹ and depressing

page_text: the arm G¹, thereby raising the tooth G2 to a position clear of E¹. The pull W³,
being now drawn, owing to the freedom of E¹ from G2 and to its engagement
with C, the lever C, and pulley D are moved to the right. By the first part
of the motion of the pulley the chain which passes over it becomes engaged in
a notch A4 in the base, and then the chain being thus held fast the further move-
ment of the pulley D gives double motion to the pull W³, which puts the distant
signal to "safety."
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When the pull W, is released the lever C is raised and then
the distant signal in rising to danger" draws the pulley D and
lever C to the left notwithstanding that the pull W₂, is not released
so that the raising to "danger" of the signal to which W is connected causes
the distant signal also to rise to danger." When the pull W2, as well as W¹,
is released, then the parts all return to the position shewn in Fig. 1, the bar E
returning to the left its tooth E³, raising Ġ² as it passes and becoming again
engaged behind it. The weights F, and F, serve to tighten the pulls Wa
and W³, respectively allowing for their expansion and contraction due to changes
of femperature. Although I have described a distant signal as the signal con-
trolled by the interlocking apparatus, obviously any other signal might be con-
trolled in the same way.
Dated this 26th day of February 1898.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION,
An Improvement in Railway Signal Interlocking Apparatus.
I, CHARLES HODGSON, of Canterbury Road, Kilburn, 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: —
"
It is often necessary to provide at a railway station means of interlocking one
signal, such for instance as a distant signal with other signals in such a manner
that the distant signal cannot be put to safety unless one or other of the
other signals are first put to "safety." This is usually effected by. suitable inter-
locking of the levers by which the signal pulls are actuated, but it may happen,
especially when the pulls extend over considerable distances, that, owing to
accident, looseness due to expansion, or to other causes the interlocking fails and
that the distant signal is put to safety" when it ought to remain at "danger."
My invention relates to an apparatus applicable to the signal pulls at any con-
venient part of their length which constitutes an indepedent interlocking
ensuring that the distant signal shall not be put to "safety" unless one or other
of the signals interlocked with it is first put to "safety," this apparatus pro-
viding also for expansion and contraction of the distant signal pull.
65
I shall describe apparatus according to my invention referring to the drawings
accompanying my Provisional Specification."
Fig. 1 is a side view and Fig. 2 is a plan. On a base A firmly fixed on the
ground at some place intermediate between the distant signal that is to be con-
trolled and the other signals which control it, is pivotted a 3 armed lever one
arm B of which has attached to it a pull W₁ from one of the controlling levers
or several of these, these pulls being kept tight by a weight on another of the
arms B2, whilst the third arm B³ has at its end a pin projecting under a lever C.
This lever which extends through a guide and is pivotted on the axis of a
pulley D, has a downwardly projecting tooth C³. A sliding bar E has attached

page_text: to its one end a pull W from the lever which should work the distant signal,
its other end has attached to it a chain passing over a pulley F to a weight Fl.
The bar E has a lateral projection E which extends upwards as a tooth. Ou
the base A is pivotted a lever, one arm G¹ of which lies immediately under the
lever C its other arm G2 being formed as a downwardly projecting tooth. The
pulley D has on its axis on each side of it a roller D¹ and D³ free to run along
tracks A', A, formed on the base A.
Over the pulley passes a chain loaded by a weight F3 and attached to the
pull W for the distant signal.
The apparatus operates as follows:-
When the parts are in the position shewn the pull Wa for the distant signal
cannot have any effect on the signal because the bar E to which it is attached is
stopped by its tooth E¹ meeting the tooth G2 and because the tooth C is clear
above the tooth E and therefore, even if G' were absent, the lever C would not
be moved. When however any one of the pulls W is drawn by the movement
to "safety" of the signal to which it is connected then the arm B³, being lowered
the lever C descends bringing its tooth C, in front of the tooth E' and depressing
the arm G¹, thereby raising the tooth G2 to a position clear of E¹. The pull W²,
being now drawn, owing to the freedom of E from G2 and to its engagement
with C, the lever C, and pulley D are moved to the right. By the first part
of the motion of the pulley the chain which passes over it becomes engaged in
a notch A4 in the base, and then the chain being thus held fast the further move-
ment of the pulley D gives double motion to the pull W³, which puts the distant
signal to safety.'
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66
When the pull W₁, is released the lever C is raised and then
the distant signal in rising to ' danger" draws the pulley D and
lever C to the left notwithstanding that the pull W2, is not released
so that the raising to "danger" of the signal to which W is connected causes
the distant signal also to rise to "danger." When the pull W2, as well as W1,
is released, then the parts all return to the position shewn in Fig. 1, the bar E
returning to the left its tooth E¹, raising Ġ² as it passes and becoming again
engaged behind it. The weights F¹, and F3, serve to tighten the pulls W³
and W³, respectively allowing for their expansion and contraction due to changes
of temperature. Although I have described a distant signal as the signal con-
trolled by the interlocking apparatus, obviously any other signal might be con-
trolled in the same way.
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. Railway signal interlocking apparatus applicable to the pull operating a
signal and so arranged that the movement of the lever for that signal is ineffec-
tive, in putting it to "safety" unless another signal is first put to "safety," the
signal pull for this purpose being made in two parts the one of which is stopped
and disconnected from the other part, until it is released and becomes connected
by the operation of a pull from the other signal substantially as described and
illustrated by the drawings.
2. In signal apparatus such as is above referred to connecting the two parts
of the pull by chains passing over pulleys to weights so as to allow for expansion
and contraction of the pulls, substantially as described.
1000
ABEL & IMRAY,
Agents for the Applicant.