An Improved Signalling Apparatus for use on Railways.
Year: 1891

page_text: Date of Application, 28th Mar., 1891
Complete Specification Left, 28th Dec., 1891-Accepted, 6th Feb., 1892
PROVISIONAL SPECIFICATION.
An Improved Signalling Apparatus for use on Railways.
I, HENRY ALFRED IVATT, of Inchicore Works, Dublin, Ireland, Mechanical
Engineer, do hereby declare the nature of this invention to be as follows :-
This invention relates to an improved signalling apparatus for use on railways
and is designed to provide convenient apparatus for indicating the passage of a
train, when the train itself cannot be seen from the station or signal box.
The apparatus which I consider it is advantageous to employ for this purpose
comprises a box or chamber provided with a movable air-tight cover or a flexible
diaphragm suitably mounted thereon, which cover or diaphragm is connected with
one end of a lever, or system of levers, the other end of which bears against the
under side of one of the rails or against a suitable arm or lever arranged to be
acted on by the train. An air tube or pipe leads from the box or chamber covered
by the diaphragm to a suitable indicator placed in the signal box or elsewhere.
When a train passes, the rail is deflected or the aforesaid arm is moved and this
movement is communicated to the diaphragm (the range of movement being
increased by the communicating lever or levers) thus producing a variation in the
air pressure in the space below the movable cover or diaphragm, which is trans-
mitted through the air pipe to the indicator.
This indicator may conveniently take the form of a shallow vessel provided at
its underside with a flexible diaphragm which is covered with water, or other fluid.
Beneath the diaphragm is a chamber connected with the air pipes so that the air
pulsations produced by the passing train move the diaphragm and cause a visible
disturbance of the fluid in the indicator. Or the indicator may be provided with a
falling disc, which is released and allowed to fall by means of a catch lever
disengaged by the expansion or contraction of an air cushion connected with the
air pipes, the fallen disc giving an indication until reset of a train having passed.
Any other suitable form of indicator, adapted to be worked by the air pulsations
may however be employed, as found desirable.
The improved apparatus herein before described may also be employed to indicate
at the signal box or station movement of a signal arm, or the like, the said signal
arm being arranged to act on or operate the lever or levers connected with the
movable air-tight cover of the box or chamber above mentioned.
Suitable arrangements may be applied to throw the apparatus out of action when
not required, either by holding the end of the lever clear of the rail, so as to avoid
wear and tear, or otherwise.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
An Improved Signalling Apparatus for use on Railways.
1, HENRY ALFRED IVATT, of Inchicore Works, Dublin, Ireland, Mechanical
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 :-
My invention has reference to that class of signalling apparatus for use on
railways in which a signalling device is operated by change of pressure of air in a

page_text: pipe-it consists in the combination and arrangement of parts. I will now describe
with reference to the drawings and which constitutes an apparatus adapted to be
operated by a passing train engine or vehicle for indicating the passage of such
train engine or vehicle when the same cannot be seen from the station or
signal 'box.
Referring to the annexed drawings,
Fig. 1 shows an apparatus partly in side elevation and partly in vertical section.
Fig. 2 is a vertical transverse central section, and
Fig. 3 a section on the line x x Fig. 2, both to a larger scale than Fig. 1, of an
indicator with a falling plate.
Fig. 4 is a section on the line y y of Fig. 2.
Fig. 5 is a plan partly in section, and Fig. 6 is a section of a modified arrange-
ment of the apparatus.
Referring to Figs. 1 to 4 inclusive,
A is a box or chamber having a thin flexible air tight cover B which may be of
sheet rubber or sheet metal corrugated or other suitable flexible material. The
cover B is connected to one end of a lever C the other end of which bears against
the underside of a rail D over which trains engines or vehicles pass. E is an air
tube leading from the box or chamber A to a suitable indicator F; this lever C
is carried on a fulcrum C' and is guided by a pin working in a fork C²; the
fulcrum C¹ is so arranged as to be capable of being turned on its centre C³ so that
when it is moved into the position shown in dotted lines, the end of the lever will
fall away from the rail and the apparatus will be put out of action. The indicator
is shown in Figs. 2, 3 and 4 it is constructed with a vertically movable plate or disc G
adapted to turn on the centre H, and which when not held up as hereinafter
described is free to fall into the position shown by dotted lines. J is a flexible
diaphragm that divides the interior of the indicator into two compartments J¹ J
one of which (J) is in communication with the air pipe E and the other (J³) with
the external atmosphere. Attached to the diaphragm is a pin I that normally
engages with a stop or catch G' on the back of the pivoted plate G so as to hold
the same up when the diaphragm is in its normal position. The frout of the
indicator is covered by a plate Fi having a circular opening F in it through which
a portion of the plate G is visible. That portion of the plate which is visible when
the plate is raised is in the active apparatus coloured differently to that portion which
is visible when the plate has fallen, thereby giving a clear indication as to the
position of the plate. G2 is a tail piece for raising the disc by hand to reset the
indicator. The action of the apparatus is as follows:-On a train passing over
the rail D the rail is depressed, and assuming the fulcrum C' to be (when the train
is passing) turned up as in Fig. 1, the said rail will move downward the end of the
lever C on which it bears, raising the other end and drawing up the cover B,
thereby causing a partial vacuum in the box or chamber A and also in the com-
mmunicating pipe E and the compartment J' of the indicator F behind the
diaphragm J. The external air pressure. acting on the opposite side of the
diaphragm then forces this diaphragm inwards thereby disengaging the pin E from
the catch G and permitting the plate G to fall.
In the modification shewn in Figs. 5 and 6, D is the rail, K is a curved lever
lying along the inside of the rail head and secured at one end to a bracket L. The
lever K is curved or bent slightly as shewn so as to be in contact with the rail head
at one part of its length, its extremities being sufficiently far from the rail to allow
of the passage of a wheel flange without striking the end of the lever. The lever may
have sufficient spring or elasticity in itself to cause it to return into contact with the
rail after being pressed therefrom by a wheel flange, or it may be pivoted and caused
to return to the rail by a weighted lever or spring as may be found desirable. The
other end of the lever K is connected to the piston B' of an air cylinder A' that
communicates by the pipe E with an indicator as before, or the arrangement shewn
in Fig. 1 and comprising the box or chamber A and flexible cover B may be
employed instead of the piston and cylinder.
21

page_text: When a wheel passes along the rail the flange of the wheel entering between the
lever K and the rail will gradually force the lever away from the rail and
the motion so obtained is used to actuate the indicator through the medium of.
the piston and cylinder, or equivalent device, and the enclosed air as described.
It will be obvious that instead of the parts being so arranged as to produce a
partial vacuum in the apparatus and to disengage the falling disc when the
diaphragm J moves inward, the air in the apparatus might be compressed by
actuating the cover B or the piston B' or a diaphragm through a suitable arrange-
ment of levers whereby they would be forced inward instead of outward, the
diaphragm J being in this case adapted to disengage the falling disc on being
moved outwards.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that I am aware
it has before been proposed to actuate railway signals by changing the pressure of
air and that I make no general claim to this but what I claim is :-
The combination of parts constituting my improved signalling apparatus for use
on railways so constructed arranged and operating as shewn in and described with
reference to the drawings a lever such as C or K being so arranged in connection
with the other parts of the apparatus that a passing train or vehicle will actuate
the said lever and through it will work an indicator of the kind referred to through
the medium of a column of air substantially in the manner described with reference
to the drawings for the purpose specified, whether the apparatus be arranged
according to Figs. 1 to 4 inclusive or modified according to Figs. 5 and 6.
Dated this 28th day of December 1891.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.