Apparatus for the Automatic Protection of Railway Trains against Collision.
Year: 1892

page_text: Date of Application, 30th June, 1892
Complete Specification Left, 22nd Mar., 1893-Accepted, 13th May, 1893
PROVISIONAL SPECIFICATION.
Apparatus for the Automatic Protection of Railway Trains against
Collision.
I, MARTINUS GERARDUS STOKVIS, of No. 39 Ouellijustraat, Amsterdam,
Kingdom of the Netherlands, Engineer, do hereby declare the nature of this inven-
tion to be as follows:-
The object of my invention is to protect railway trains provided with pneumatic
brakes, against collision with another train running on the same track towards the
first one from ahead or from behind. For this purpose I insert into the pipe of
the pneumatic brake-operating mechanism of each train a cock controlling the said
mechanism, and I so arrange the plug and key thereof that, when the cock is
closed, the brakes being then withdrawn from the wheels, the key will be in such
position as to be capable of striking against an obstacle placed in its path and to
be turned thereby, together with the plug of the cock, with the effect of causing
the brakes to be applied. Moreover, I dispose along the track pneumatic devices
to be operated by the train to be protected, and which in turn operate, at the
required distance forward and rearward, mechanisms whereby the aforesaid
obstacles are brought into, and kept for some time in the proper position for acting
on the key of the cock of any train endangering the former. These devices are
arranged on both sides of the track, so that two trains running towards each other,
may cause a reciprocal action of their brakes.
The said pneumatic devices consist cach in two closed receptacles of variable
capacity (each as bags of india rubber, or cylinders with pistons) containing air
or other gaseous fluid and connected by a pipe, the said receptacles being placed
apart at a distance equal to about twice the shortest distance to be allowed between
the trains. One of these receptacles is normally maintained by a spring in
expanded state, while the other is in contact condition. With the receptacle being
normally expanded, is combined a cam-lever so arranged that any train passing
over the same, will depress it by the rims of the wheels or by means of a roller,
the said cam-lever then operating to compress the expanded receptacle and to force
air therefrom through the connecting-pipe into the contracted receptacle. By the
increase of volume of the latter thus produced, a lever constituting the aforesaid
obstacle is raised into the path of the said key. In order that, subsequent to such
raising, the lever may remain in raised position until the operating train has caused
the following lever to be raised, the receptacle which is normally expanded, is
placed in a closed casing provided with appliances for allowing air to enter there-
into freely from the outside when the said receptacle is reduced in volume, and to
issue slowly. By these means both receptacles and the said lever are permitted
to return but slowly to their normal state and position. In order, however, that
the levers which a train has caused to be raised in front of it, may not act on
its own brakes, they are arranged to be depressed by tappets provided for on the
train.
With the receptacles are combined devices for allowing some air to pass out
if it becomes expanded by heat, and to enter thereinto if the air inside contracts
from cold.
In consideration of the particular functions of the two groups of parts described,
the group comprising the compressible receptacle and the cam-lever, may be called
the pressure-generator, the other group the blocking device.
Dated the 30th day of June 1892.

page_text: COMPLETE SPECIFICATION.
Apparatus for the Automatic Protection of Railway Trains against
Collision.
I, MARTINUS GERARDUS STOKVIS, of No. 39 Quellijustraat, Amsterdam,
Kingdom of the Netherlands, Engineer, do hereby declare the nature of said
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:—
The object of my invention is to protect railway trains provided with pneumatic
brakes, against collision with another train running on the same track towards the
first one from ahead or from behind. For this purpose I insert into the pipe of
the pneumatic brake-operating mechanism of each train a cock controlling the said
mechanism, and I so arrange the plug and key thereof, that when the cock is closed,
the brakes being then withdrawn from the wheels, the key will be in such position
as to be capable of striking against an obstacle placed in its path and to be turned
thereby, together with the plug of the cock, with the effect of causing the brakes
to be applied. Moreover, I dispose along the track pneumatic devices to be
operated by the train to be protected, and which in turn operate, at the required
distance forward and rearward, mechanisms whereby the aforesaid obstacles an
brought into, and kept for some time in the proper position for acting on the key
of the cock of any train endangering the former. These devices are arranged on
both sides of the track, so that two trains running towards each other, may cause
a reciprocal action of their brakes.
The said pneumatic devices consist each in two closed receptacles of variable
capacity (such as bags of india rubber, or cylinders with pistons) containing air or
other gaseous fluid and connected by a pipe, the said receptacles being placed apart
at a distance equal to about twice the shortest distance to be allowed between the
trains. One of these receptacles is normally maintained by a spring in expanded
state, while the other is in contracted condition. With the receptacle being
normally expanded, is combined a cam-lever so arranged that any train passing
over the same, will depress it by the rims of the wheels or by means of a roller, the
said cam-lever then operating to compress the expanded receptacle and to force air
therefrom through the connecting-pipe into the contracted receptacle. By the
increase of volume of the latter thus produced, a lever constituting the aforesaid
obstacle is raised into the path of the said key. In order that, subsequent to such
raising, the lever may remain in raised position until the operating train has caused
the following lever to be raised, the receptacle which is normally expanded, is
placed in a closed casing provided with appliances for allowing air to enter thereinto
freely from the outside when the said receptacle is reduced in volume, and to issue
slowly. By these means both receptacles and the said lever are permitted to return
but slowly to their normal state and position. In order, however, that the levers
which a train has caused to be raised in front of it, may not act on its own brakes,
they are arranged to be depressed by tappets provided for on the train.
With the receptacles are combined devices for allowing some air to pass out
if it becomes expanded by heat, and to enter thereinto if the air inside contracts
from cold.
In consideration of the particular functions of the two groups of parts described,
the group comprising the compressible and the cam lever, may be called the
pressure-generator, the other group the blocking-device.
In the annexed drawing
Fig. 1 is a sectional view showing one of the systems of communicating pressure-
generating and blocking devices.
Fig. 2 illustrates a modification of the cam lever.
Fig. 3 represents in plan a portion of a railway-track provided with the automatic
protector, the construction being considerably condensed in length.

page_text: In Fig. 1, P is the normally expanded, and P¹ the normally contracted receptacle,
both consisting in bags of india rubber or other suitable material and connected
together by the pipe p. The receptacle P is located in a casing p', hermetically
closed by a resilient metallic membrane p², which, in addition to its forming the top
of the casing, serves as spring to keep the receptacle P expanded. Upon the
latter is placed a hollow metallic disk po, and the membrane p³, the disk po and the
upper wall of receptacle Pare secured together by a screw and a nut on the piece v¹,
forming a connecting link between the receptacle P and the cam-lever v. This
lever, pivoted at 2, is arranged horizontally by the side of the rail S, and it is
provided with the projection or cam V having such position as to be acted upon from
above by the rim of any wheel of a train passing over the same, the effect thereof
being that the cam-lever will be pressed down and the receptacle P compressed or
reduced in capacity. In consequence of this compression a portion of the air
contained in receptacle P will be forced through pipe p into the contracted or
collapsed receptacle P, thereby expanding the same. In order that this expansion
take place in the direction upward only, the receptacle is inclosed in a casing p²,
and it is fitted at the top with a disk po for stiffening it and guiding it in the casing.
The said expansion is utilized to raise the lever B, connected by link band a rod
to the top of the receptacle P1, and pivoted at a point 62 lying from link towards
the receptacle P. The spring 2² serves to assist in recompressing the receptacle P
when relieved of pressure. The lever B is so formed that, when raised by the
expansion of receptacle P₁, as indicated by dotted lines in Fig. 1, its end & will be
in the path of the key a of the cock A controlling the pneumatic brake (not shown
in the drawing) of the train to be stopped. The said lever I shall hereafter call
blocking-lever.
For the purpose of keeping the blocking-lever B for some time in raised position,
the space L formed in the casing pl of receptacle P between' the membrane p
and the convex top of disk po, is put in communication with two closed vessels 1
and containing glycerine or other suitable liquid, by means of the respective
pipes and which dip into the liquid so as to be closed hydraulically, while
pipes and establish communication between the air-spaces of the respective
vessels and land the outer air. Whenever a compression of the receptacle P
takes place, the space L will be increased in volume. Consequently air will be
drawn into the same through the pipes and I, the liquid in vessel preventing
its reissue along this path. As soon as thereafter the receptacle P is relieved of
pressure and the membrane p³, operating as spring, begins to reexpand it, thereby
reducing the volume of space L, air will flow out through pipe P, vessel 1 and
pipe. But, in order to retard this efflux, the pipe is contracted at its end
dipping into the liquid, and besides it is provided with a regulating-cock. The
reexpansion of receptacle P and consequent recontraction of receptacle P¹ therefore
take place slowly, so that lever B is not drawn down again until some time has
elapsed, this time requiring to be regulated by means of cock in such manner that
each lever B will remain in raised, i.e. operative, position until at least one of the
following blocking-levers of the series has been raised, so that there be always one
or more blocking-levers in the path of the key a of the train running towards the
one that operates the levers.
In view of assisting to keep the blocking-levers raised, they are provided above
their fulcrum & with a weight which is tilted from one side of the vertical line
passing through their fulcrum, to the other.
For the purpose of preventing the operation of the apparatus from being
prejudicially influenced by expansion and contraction of the air in receptacles P
and P, due to variations of temperature, devices are provided for through which
air can escape from the receptacles when the pressure inside is higher than outside,
and whereby air is admitted in the contrary case. The device for allowing air to
escape may consist in a valve w of suitable weight closing an aperture commu-
nicating by a pipe W with pipe p, the valve opening outward, while the device
shown by the drawing for allowing air to pass in, consists in the closed vessel k

page_text: containing a liquid, such as glycerine, pipe K' forming a communication between
pipe p and the air-space in vessel k, and pipe K dipping into the liquid and opening
out into the outer air. The operation of these devices is obvious. Any water of
condensation that may be formed in the receptacles and in pipe p, is collected in
vessel c,. towards which the parts of pipe p are inclined.
This water may be
removed by a pump introduced through pipe C.
Instead of operating the cam-lever by the wheels of a train, it may be actuated
by rollers such as a', Fig. 2, attached to the frame of the engine or of a carriage.
The lever in this figure is substantially the same as lever, Fig. 1, only its form
is different.
Of the described automatic protectors there are arranged along the track two
series, one for protecting a train in front, the other for protecting it in the rear.
The blocking-levers of one series are marked with the letter B carrying the indices
from 1 to 5, those of the other series with the same letter having appended to it
the indices (1) to (5). The expansible receptacles, the compressible receptacles
and the cam-levers acting on the latter, are marked with the respective
letters P, and V, the latter carrying the same indices as the blocking-levers, to
which they belong. The rectangles Z and Z' indicate two trains, and a, a², a³, a
the keys of the cocks in the air-pipes.
Now, supposing train Z, running in the direction of arrow 1, to be advancing
from the right towards the part of the track shown in the drawing, it will act on
the cam-levers being the next outside of the limits of the figure, and thereby cause
the blocking-levers B B B to be raised in succession. Supposing, moreover, that
before the train has attained the point at which it is shown in the drawing,
levers B1 and B2 have been drawn down again, while lever B3 may be about to
be drawn down, then the train, on passing over cam-lever V, will press down this
lever and cause blocking-lever B3 to be raised in position to protect the train in
front. In like manner, train Z, if running in the direction of arrow 2, will,
previous to its attaining the position in which it is shown, act on the cam-levers in
connection with blocking-levers B) B(2) B(3), so as to raise the latter in succession,
the levers B and B having, however, been drawn down again before the train
passes them, while lever B may be about to be lowered, because now cam-
lever Vis depressed and causes lever B to be raised. If thereafter the two
trains advance further towards each other, train Z will have its brakes put into
operation as soon as key a² touches against lever B, while train Z' will be acted
upon in like manner by the contact of its key a³ with lever B. Both trains will
thus be stopped while being apart from each other by a distance about equal to
that between levers B and B ; i.e. the part of the track between the levers B
and B is in this case blocked for both trains.
Every train, however, also protects itself against collision with a faster train
running towards it from the rear. Thus if trains Z and Z run both in the
direction of arrow 1, train will have acted in succession on the cain-
levers V, V, V(5), V(), so as to produce a raising of the blocking-levers
connected thereto, before train Z reaches them. When train Z is depressing
cam-lever V, it is blocking-lever B) which is in the path of key a² of train Z,
therefore if train Z were at this moment to come up to lever B, its brakes
would be put in operation by the same with the effect of stopping the train,
whereas train Z pursues its course.
As it might happen that a blocking-lever raised by a train in its front, be not
drawn down again before the train comes up with it, the lever being then apt to
cause the operation of its own brakes, it is necessary to furnish each train with a
tappet adapted to throw the lever down. As such may serve the keys a of the
cocks A, provided these be fitted with a shoulder a* preventing the keys, when
thus acting as tappets, from being turned backward.
For this purpose of enabling any engine to profit of the described protecting-
apparatus in case it should run backward, it is furnished with two keys for operating
the brake-controlling cocks, one at the head on one side and the other at the rear

page_text: on the opposite side, in like manner as the train Z is shown fitted with the keys a a²
and the train Z with the keys a² a*.
In order that one train may also cause crossings, &c., to be blocked against the
passage of other trains, each branch of the same is provided at a suitable distance
from the crossing with a pressure-generator and with each of these are connected
one or more blocking devices on the other branches. Moreover, on stations there
may be arranged blocking-devices connected with pressure-generators to be worked
by hand-levers.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
An apparatus for the automatic protection of railway-trains provided with
pneumatic brakes, against collision, so constructed and disposed that the train
through its wheels or rollers (a Fig. 2) depresses successively levers (v) and
thereby compresses one after the other air-receptacles (P) arranged in two series,
each air-receptacle of one series discharging the air through a tube (p) in a
rearwardly arranged receptacle (PI) raising thereby blocking-levers (v) in the
path of cocks (A) controlling the pneumatic brakes on the train, whilst each air
receptacle of the other series acts in the same manner to raise into operative
position blocking levers situates in forward direction, the first named blocking
levers being returned in inoperative position by their own weight under the control
of air cocks (), and the blocking levers named in the second place being
depressed by the train itself, substantially as and for the purpose described.
Dated the 22nd day of March 1893.
J. H. JOHNSON & Co.,
Agents.