IMPROVEMENTS IN APPARATUS FOR OPERATING SWITCHES, SIGNALS, AND BARRIERS ON RAILWAYS
Year: 1881

page_text: LETTERS PATENT to Herbert John Haddan, of Kensington, Middlesex, for an'
Invention of "IMPROVEMENTS IN APPARATUS FOR OPERATING SWITCHES,
SIGNALS, AND BARRIERS ON RAILWAYS." A communication from abroad by,
Doctor Hermann Aron, of Berlin, Germany.
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 24th September 1881.
HERBERT JOHN HADDAN, of Kensington, Middlesex. IMPROVEMENTS IN
APPARATUS FOR OPERATING SWITCHES, SIGNALS, AND BARRIERS ON RAILWAYS."
A communication from abroad by Doctor Hermann Aron, of Berlin, Germany.
"
This Invention relates to switches, signals, and barriers which are controlled
from a common centre by hydraulic pressure, a simple pressure of the hand on a
lever sufficing to operate the said appliance. In order to secure switches and
barriers in the position they are intended to take, I combine with this improved
system a pneumatic accumulator or air vessel, which may be common to all
apparati of one system, and which begins to act only in the last moment of the
depression of the lever. This arrangement allows a train to pass over the switch
independently from the lever, and causes the switch to automatically assume its
former position after the train has passed over it. Moreover, the air vessel or
accumulator has the advantage of compensating for the expansion of the liquid
through temperature and small losses of the liquid.
If the switch is not required to recede automatically after a train has passed, an
accumulator with low pressure may be used instead of one with high pressure (as
used in the former case), or a liquid column which simply has to compensate for
Sinall losses and changes of temperature, and to prevent the intrusion of air.
In this case the pressure in the apparatus is less when at rest than during the
depression of the lever, and it does not suffice for moving the switch. The whole
controlling apparatus consists of three substantial parts, vis. :--
A, central controlling apparatus; B, controlling apparatus at the switch, signal,
or barrier; C, system of conduit pipes.

page_text: The central controlling apparatus consists essentially of a hand lever H, with
stopping arrangements, two bydraulic cylinders with pistons, valves, and a controlling
arrangement.
The hand lever may be placed vertically between the two bydraulic cylinders,
and connected with the piston in such a manner that when the lever occupies one
of its extreme positions, right or left, one of the piston rods is up while the other is
down. Before either of the two pistons reaches its lowest position it depresses the
stem of a valve, thereby opening the latter and establishing communication with
the accumulator. When not depressed by the piston the valve is prossed on its
sent by a spring.
The down motion of one piston presses the water into the corresponding
hydraulic cylinder of the switch, thereby causing its piston to move the switch one
way. The down motion of the other piston (commanded by the same lever) causes
the return motion of the switch by pressing water into its corresponding bydraulic
cylinder at the switch end. By reverving the hand lever the valve is closed, and
the piston (which has been at its lowest position) raised a little, after which it
remains stationary, because it is connected with the hand lever in such a manner
that the latter can press the piston into its cylinder, but not draw it out of its
cylinder. Only when the motion of the switch presses the corresponding piston
into its cylindor (local or switch cylinder) the main or central piston is pressed
out of its cylinder in proportion to the travel of the switch. On this reaction the
correct action of the controlling apparatus and of the switches is based.
The hydraulic cylinder at the switch end may be situated between or right and
left of the rails, or only on one side of the railroad, and be protected by iron
casings. One of the piston rods may be connected with the switch signal, and
thereby operate the latter. If the cylinders are placed between the rails, the con-
necting rod between the two switch points may be partly replaced by a frame
surrounding the two cylinders, and moved by two collars attached to the piston
rods. The axes of the two cylinders may be placed in one line or parallel with
each other. The waste spaces of the two coupled cylinders (that is to say, the
sides on which the piston rods are situated, and where the pressure does not act)
may be connected by a small pipe through which air passes alternately from one
cylinder into the other. Signals and barriers are operated from the central station
similarly as the switches. In order to diminish the pressuro in the pipes while the
apparatus is at rest the switch is provided with a compensating and a locking
action. If one of the hydraulic cylinders or the mechanism connected with it gets
out of order it can be temporarily replaced by applying a weight to the mechanism
of the respective side. Such a weight may also be permanently used instead of a
second press cylinder. An optical indicator, consisting of movable coloured discs,
may be combined with the pistons of the central switch-operating apparatus, said
indicator being actuated by the hand lever and also by the returning liquid. The
central switch operating apparatus may also be provided with a incchanical
controlling appliance, which secures the hand lever in its extreme position by
means of a clich falling into the notches of two sectors when the switch is in its
normal condition.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Haddan in the Great Seal Patent Office on the
24th March 1882.
HERBERT JOHN HADDAN, of Kensington, Middlesex. "IMPROVEMENTS IN
APPARATUS FOR OPERATING SWITCHES, SIGNALS, AND BARRIERS ON RAILWAYS."
A communication from abroad by Doctor Herinann Aron, of Berlin, Germany.
The appliances illustrated by the accompanying Drawings have for their
object to operate switches and barriers from a common centre, with the appli-
cation of liquids for the transmission of pressure, and solely by the power of a
handlever. The safe closing of the switch, and the securing of the signals or
barriers in their new position with the application of high pressure apparatus, is
effected by the pressure of an accumulator or air vessel, which begins to act only
in the last moment of the motion of the lever, and which may be used for all
apparati of the same system. This arrangement allows a train to pass over the
switch independently of the lever, and the switch to automatically assume its
former position after the train has passed over.
Morcover the air vessel or accumulator has the advantage of compensating for
the expansion of the liquid through variations of temperature, and also for small
losses of the liquid.
If the switch is not required to recede automatically after a train has passed, an
accumulator with low pressure may be used instead of one with high pressure (as
used in the former case), or a liquid column which simply has to compensate for
small losses and changes of temperature, and to prevent the intrusion of air.
In this case the pressure in the apparatus is less when at rest than during the
motion of the lever, and it does not suffice for moving the switch. In the latter
case a switch locking device must be used.
The whole controlling apparatus consists of three essential parts, viz. :—
A, central controlling apparatus, Figures 1-7c, and 21-25-30.
B, controlling apparatus at the switch, signal, or barrier, Figures 8–20, 22–24,
31-33.
C, system of conduit pipes.
A. The contral apparatus is the same for switches, signals, and barriers.
In the accompanying Drawing,—
Figures 1 and 2 show the general arrangement of the controlling apparatus in
the station.
Figures 3 to 7c, details of the same, with vertical press cylinders, which however
may have any other position.
Figures 8 and 9, switch controlling apparatus situated on both sides of the line
or track of rails.
Figures 10 to 12, the arrangement of the same between the rails.
Figures 13 to 15, controlling apparatus on one side of the track only, with two
cylinders having their axes in one straight line.
Figures 16 to 18, controlling apparatus on one side of the track only, with two
parallel cylinders.
Figure 21, selfacting central controlling apparatus, with horizontal cylinder.
Figure 22, the arrangement of a controlling apparatus, with one cylinder and
counterweight at the switch.
Figures 19, 20, 23, and 24, arrangements of regulating apparatus for signals.
Figures 25 to 30, central controlling apparatus for the low pressure system.
Figures 31 to 33, controlling apparatus at the switch for the same system.

page_text: The central controlling apparatus consists essentially of a hand lever H with
locking appliances, two hydraulic cylinders C, C', with pistons K, K', valves v, v',
and a regulating levice. Figure 3 shows the position of the lever H, when the
piston K is in its lowest position, and the valve v opened by the down motion of
the said piston; the conduit L is therefore under the pressure of the accumulator.
The piston of the press cylinder c, corresponding to this conduit and situated at
the switch end, is at the same time pushed outward as far as to press the tongue
Z against the rail S. The piston of the other cylinder c' at the awitch is
meanwhile pressed into its cylinder, because the conduit L', corresponding to the
cylinder c', is merely subject to the pressure of the atmosphere and of the weight
of the piston K', which is in its highest position.
By moving the lever H into the extreme position e¹ indicated in Figure 1, the
piston K' descends into the cylinder Cowing to the pressure of the rod 8'; the
liquid in the conduit L' transfers to the piston (Figures 8 and 19) the motion
imparted to piston K, whereby the position of the switch is reversed.
Shortly before reaching the lowest position the piston K' opens the valve v³,
thereby setting the conduit L' under the pressure of the accumulator or air vessel.
This latter arrangement causes the switch to close safely and tightly to the rail,
and to assume its former position according to the position of lever H after the
train has passed over.
By reversing the lever H, the valve (Figure 3) is closed by means of a spring f
the piston K is at the same time slightly raised and then stands still, the connection
of the piston with the lever H being such that the lever presses the piston K into
the cylinder C, but cannot draw it back from the same.
The piston K (Figure 3) is pushed out of the cylinder C by the motion of the
switch only, which presses the piston into the cylinder c, thereby displacing the
piston K from the cylinder C in proportion to the motion of the switch.
On this reaction depends the control over the working of the apparatus and over
the adjustment of the switch.
For this purpose 1 connect the two pistons K and K' with the two levers h and h¹,
which turn on A by means of two connecting rods 1, 1, and a spring F in such a
manner that the up motion of the piston (which is produced by reversing the
switch independently of the lever H) is transferred upon vertical rods t, t¹.
These two rods are connected with two movable and differently colored discs m, m¹
(one green, the other white). According to the position of the switch for the one
or the other direction of the train, either one or the other of them is visible
through an orifice o. If the disc cannot be seen entirely or not at all, so as to allow
of seeing the red stripe of metal behind the orifice o (Figure 2), it denotes that
the switch does not fit to the rail, or has not moved at all. The indiret connection
of the two pistons by means of the spring F, compensates for a possible lead of the
disengaged piston which occurs easily, and would prejudice the accuracy of the
control.
Each of the levers h and h' carries on an upright arm a sector p or p', with a
notch or i¹, and into these notches falls the catch g' when the switch acts
regularly, said catch being connected with the catch of the lever H. These
catches g, g¹, are rigidly connected with each other.
Supposing the regular acting of the switch to be disturbed, for instance, by
foreign bodies falling between the switch tongue and main rail, the free piston will
not finish its travel; consequently the notch of the sector does not reach as far as
the catch g' of the lever H, which catch only slides upon the sector; in consequence
of this the latch is prevented from falling into the notches e, e', designed for
keeping the lever H in its extreme position. On the contrary, the lever His
thrown back by the pressure of the liquid under the other piston. This is the
mechanical control of the functions of the switch, while the optical control is
formed by means of the colored discs m, m', as described.
After re-establishing the normal conditions of the switch all parts act again as
before.

page_text: The screws applied to the cylinders (Figures 1 and 3-7, &c.) serve to remove
air from the cylinders and conduits, &c., before setting the whole apparatus in
motion.
B.-The operating apparatus at the switch, signal, or barrier, is shown by the
accompanying Drawings in four different modifications.
Figures 8 and 9 show an arrangement of controlling apparatus with the piston-
rods,, fork-shaped and connected by means of bolts with the pieces T, T',
which are riveted to the tongue of the switch.
The rod M leads to the switch signal through a hole in the wall of the casing B.
The cylinders and casings rest on the plates P, P', which are screwed to the two
supporting sleepers.
Figures 10-12 show the controlling apparatus situated between the line. In
this arrangement I connect the two switch-tongues Z, Z, by a frame R instead
of a rod, said frame surrounding the press cylinders c, c', as shown. The pistons k, k³,
of the cylinders c, c', however are not secured to the frame R, but press on the
same merely by means of their round heads D, D¹, whereby a perfect independence
of the apparatus and switch is obtained.
For protecting the cylinders they are covered by a metal casing B, which is
secured to the frame R.
Figures 13 to 15 show the apparatus arranged on one side of the track only, the
same being provided with two cylinders in one line resting on one common plate P.
The pistons k, k, of the apparatus are connected with each other by rails n, which
take the lever g between them.
Figures 16 to 18 show the apparatus with two parallel cylinders c, c¹, on one side
of the track, said cylinders being connected by the pistons k, k¹, with a lever q.
The adjustment of the apparatus for a given travel of the switch is produced by
altering the effective length of lever q, as shown in Figs. 16-18, where a screw
spindle and nut q' with an eye for the switch-draw-rod is used, the screw thread
being applied to the end of the lever.
In Figures 8-18 the draw rod of the switch-point is designated with W, and the
connecting rod for the optical signal of the switch with M.
In order to prevent dust from entering the cylinders through the openings a, a¹,
designed to admit air to the back of the pistons k, k', I connect the cylinders by
means of a pipe U, through which the air passes alternately from one cylinder into
the other.
C-L, L, of the Drawings denote the junctions to the conduit pipes for the
liquid.
As already mentioned, the arrangement of the central apparatus for controlling
the signals is the same as for controlling the switches.
Figures 19 and 20 show the controlling apparatus at the signal end of the
conduit.
In the cylinders c, c', move the pistons k, k¹, connected with the rods y, Y¹.
These rods transfer the motion communicated to the pistons k, k¹, from the central
place upon a lever I moving in a vertical plane, and from this lever I a wire N
leads to the signal-arm.
For operating barriers I use the same arrangement of apparatus as for signals.
In the case of one part or the other of these above described apparati refusing
to act, for instance, a press cylinder or one of the conduits for the liquid under
pressure, one side of the apparatus is set out of action in any suitable way, and
the controlling apparatus at the switch end provided with a weight, as shown in
Figures 16 and 17 in dotted lines, sufficient to replace the pressure of the other
press cylinder k¹.
This system may be permanently used for single-cylinder apparatus, as shown in
Figures 21-24.
For these I only require one cylinder central apparatus (Figure 21), and one
cylinder switch-apparatus (Figure 22), or one cylinder signal apparatus (Figs. 23

page_text: The one cylinder system works in the same manner as the two cylinder system,
with the difference however that when the lever H is reversed the switch and
piston K must move by the effect of the weight a (Figures 22, 23, and 24).
The application of the apparatus described above subjects all parts which are
directly connected with the pressing liquid to high pressure, and as all parts suffer
more or less under this pressure it is advisable to remove or reduce the same while
the switch is at rest, so that small losses of liquid and variations of temperature
may be compensated, and the intrusion of air prevented. These advantages are
secured by a compensating apparatus at the switch end, and by locking the switch
through the controlling apparatus. In this case the pressure occurs only while the
switch is being reversed.
The apparatus for this system, the low pressure system, is represented by
Figures 25-33.
It is composed of
1. The apparatus at the central-station for switches, signals, and barriers
(Figures 25-30), consisting of the hand lever H, the links L, L, the pistons K, K',
with the packings M, M, the cylinders C, C, with projections A, A', and per-
forations b, b', b, the pipes R, R¹, and sectors S, S¹.
2. The conduits l, l¹.
3. The apparatus at the switch, signal, or barrier, as illustrated by Figures 31-
33, and consisting of the cylinders c, c', pistons k, l, the cam 8, lever h, with
rollers,, and rod v.
The apparatus operates. as follows:-If the lever El is placed in the position
represented by Figure 1 the piston K' is pushed into the cylinder C', whereby the
piston at the switch communicating with the latter through the conduit is
pushed out of the cylinder c' (Figure 31), and the liquid contained between the
two corresponding pistons completely enclosed, consequently if the lever H is locked
by the falling in of its latch a back motion of the piston is impossible.
The liquid contained in the conduit is in this case not completely shut in, but
communicates through a small bore b and the pipe R (Figure 25) with a high level
reservoir for the purpose of replacing any wasted liquid.
If the lever H is reversed the piston K is pressed into the cylinder C by means
of the links L, and the connection of the conduit with the reservoir immediately
broken by the packing M' of the piston K being placed before the orifice b, in
consequence of which any further inward motion of the piston K causes the
piston at the switch end (Figure 32) to be pressed out of its cylinder c by the
liquid, which is now completely enclosed.
The motion of the piston k is transmitted upon the switch and the piston by
the cam 8.
If a foreign body enters between the switch and the main rail the motion of the
lever His stopped before reaching its extremno position, because the liquid contained
in the conduit finds no escape. If there is a leak in the conduit the piston K'
will no longer follow the lever H, because the quantity of liquid returning from
the switch to the central station is not sufficient, and because the lever H can only
exert a pressure, not a traction, on the pistons K and K'; consequently the 4
sector S¹ connected with the piston K by the links L' will be turned on the bolt a
during its further motion with the lever H, and in resting against the projection A
will prevent the complete reversal of the lever H, which is thus only possible after
the complete closing of the switch.
Small and unimportant losses are replaced by the arrangement of the sector S¹, 5
which shortly before the end of the stroke of the lever H slides upon the oblique
face A', thereby slightly drawing out the piston K' and causing a suction of water
from the reservoir.
An essentially improved modification of the apparatus at the central station is
represented by Figures 28-30; the improvements consist in providing the rear 5
portion of the cylinder with a new radial perforation 6 and the frame with two

page_text: new stop pins and ', while the sector S is provided with corresponding detents
and 6. The perforation b' is so located that on the completion of the stroke the
rear packing M' has just passed it and laid it open; this causes the liquid in the
conduit to communicate with the reservoir through the orifices 62, b', and b, to
compensate for variations of temperature; the controlling piston communicates
with its reservoir, as before, through the corresponding orifice b, so that both
conduits are only under the low pressure of the liquid column as long as the switch
is at rest.
In order to prevent the liquid to escape through the perforations b, b¹, and b²,
into the reservoir when the switch is again reversed and the liquid returns to the
controlling apparatus, it is necessary to close the orifice 6' at the beginning of the
stroke.
This is effected by the nose of the sector S' and the stop or detent 5 on the
upper part of the frame. On reversing the lever H the controlling piston is drawn
out until the detent of the sector leaves the stop pin 51, because the sector is
prevented from turning as long as the stop pin is in contact with the detent 5;
the latter is so adjusted that after the action of the pin the packing closes the
orifice, from which time only the controlling liquid can continue to press this
piston outward. The oblique face a of the projection A for the sector S is in the
present modification separated from A and replaced by the contact pin ¹, to which
corresponds a nose ò on the sector. This nose has two sliding faces T and T¹, of
which the former extends from the point or apex upward, while T' extends
downward. If there is a small waste of liquid the lower face r' of the nose comes
in contact with the pin & and draws the controlling piston out to the end for
replacing wasted liquid.
In case of greater waste the sector has a lower position, which causes the upper
face r to come in contact with the pin &, thereby leading the sector downward
towards the contact A.
The cam s of the switch locking mechanism, as represented in Figures 31-33,
turns on the pivot Z; the curves 8' and are symmetrical to the longitudinal
axis and terminate in arcs of circles; they serve as guides to two rollers r and r
of a system which turns on a second pivot Z. The lever h of this system is in
direct connection with the switch tongues by means of the switch rod v.
The cain 8 transmits the motion from the central apparatus upon the lever h in
such a manner that the last part of the notion of the cam takes place after
the closing of the switch, the said arcs of circles being thereby placed against
the rollers to prevent any further motion of the lever h and to lock the switch
completely.
The cain is so designed that during its uniform rotation the switch moves
with variable speed, commencing with zero and increasing towards the centre, from
which it decreases again towards the end, whereby a smooth motion of the switch
is secured.
In order to prevent the cam from striking against the rollers at the first
moment of its motion its shape is such that the cam lies against both rollers at the
end of its travel, although this may not be the case in the middle of the travel,
where only the active roller need be in contact with the cam. The cam and the
rollers are in the same lan
1st. A hydraulic central controlling or operating apparatus for controlling
switches, signals, and barriers on railways, which consists of a controlling apparatus
at a central station (as in Claim 2), two conduits for the pressing liquid L, L', in
combination with an accumulator, air vessel, or liquid column, and a controlling
apparatus at the switch, signal, or barrier (as in Claims 4, 5, and 6), working under
high pressure without compensation, or with compensation and a switch locking

page_text: arrangement for relieving the apparatus and conduits of high pressure while the
switch or signal, &c., are at rest.
2nd. In bydraulic controlling apparatus for switches, signals, and barriers, a
controlling apparatus at the central station (Figures 1-7), which consists of
(a). Two press cylinders C, C', with pistons K, K¹, so arranged as to receive 5
motion from the lever H by pressure but not by traction.
(b). Two valves v, vl, (Figures 7 and 7") or slides (Figures 7b and 7e) for alternately
establishing and interrupting the connection of the pipe conduit with the accu-
mulator, air-vessel, or liquid column by means of the pistons K, K¹.
(c). The optical controlling appliance, so arranged that the motion imparted to 1
the pistons K and K' of the central apparatus by the hand lever H and by the
returning liquid is transmitted by means of levers h and h¹ upon alternately visible
discs m and m' (Figs. 1 and 2).
(d). The mechanical controlling appliance in which the lever H can only be fixed
in its extreme positions by means of a bolt g¹ secured to the lever H and falling 1
into the notches of two sectors p and p¹ secured to the levers h and h¹ if the switch
is in order.
3rd. The application to hydraulic central controlling apparatus of a single
press cylinder CĊ with a valve vat the central apparatus, a press conduit L in
combination with an accumulator, air-vessel, or liquid-column, an optical and 2
mechanical control, and a single press cylinder c at the switch or signal in connection
with a weight G (Figures 16 and 22-24).
4th. The controlling apparatus at the switch, as shown in Figures 16-18, with
direct or indirect connection with the switch signal, consisting of two parallel
press-cylinders c, c¹, mounted on one plate, pistons k, k, pipe U connecting the 2
spaces before the pistons in order to provent the intrusion of air and dust, lever q
in combination with adjustable nut q¹ and the two screws for removing air, finally
the casing B.
5th. The controlling apparatus at the switch between the switch tongues,
Figures 10, 11, and 12, consisting of two cylinders c, c², in one axis, connecting
pipe U, pistonsk, k, pressing heads D, D¹, and frame R conuecting both switch
tongues, thereby avoiding a rigid connection of the controlling apparatus with the
switch.
6th. The controlling apparatus at the switch on one side of the track only
(Figures 13 and 14), consisting of the cylinders c and c¹ placed in one axis on a
base plate P, fish plates n, lever q, pistonsk, k³, connecting pipe U, cylinders c, c¹,
and protective casing B.
7th. In low pressuro apparatus at the central station the combination of the
packing M or M' with the orifice b or b' for the purpose of connecting the conduit
or with the liquid reservoir (see Figs. 25 and 28).
8th. The mechanical controlling appliance consisting of the links L, L', in
combination with the pins t, t', sectors S, S¹, and projections A, A1, for preventing
the lever from assuming its extreme position before the switch is closed.
9th. The oblique face a of the projections A and A¹, together with that of the
sectors S and S', for completely drawing out the controlling piston in order to
secure the opening of the orifice 6 in case of unimportant losses of liquid.
10th. The combination of the orifices b, b1, b2, (Figures 28-30) for the purpose of
opening the pressure side of the liquid conduits in order to compensate for influences
of temperature.
11th. The arrangement of the contact or detent on the sector S (Figures 28-30)
and of the contact pin on the frame for interrupting in due time the commu-
nication of the controlling liquid with the reservoir.
12th. The arrangement of the contact pin 8' (Figures 28-30) and the corre-
sponding nose on the sector S for the purpose of completely drawing out the
controlling piston in case of small losses of liquid, and also for the purpose of
deflecting the sector downward in case of more important losses of liquid.
13th. The apparatus at the switch (Figures 31-33) with a switch locking

page_text: appliance, which effects the motion of the switch by means of a cain 8 turning on a
pivot Z and acting on rollers 7, movable in the same plane as the cam for
securing the gradual and smooth working of all parts.
The whole substantially as described and illustrated.
In witness whereof, I, the said Herbert John Haddan, have hereunto sel
my hand and seal, this Twenty-fourth day of March, A.D. 1882.
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