IMPROVEMENTS IN RAILWAY BRAKES
Year: 1873

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
“IMPROVEMENTS IN RAILWAY BRAKES.”—A communication from abroad
Scaled the 9th December 1873, and dated the 8th July 1873.
:
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 8th July 1873.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN RAILWAY BRAKES," to be as
follows:-
This Invention, which relates chiefly to improvements in electric
brakes, is illustrated in the accompanying Drawings.
The whole apparatus is hung like a pendulum from the carriage"
framing on two pivots P, P, one of which only is visible in the sectional
elevation, Figure 1,

page_text: At the middle of a horizontal shaft A, Figure 2, is keyed a horizontal
electro-magnent having four poles C, C, sec Figures 2, 3, and 4, and at
each end of the said shaft is placed a circular electro-magnet L, Figures 2
and 5. These two magnets L, L, are disposed within a short distance of
the wheel axle Q, against which they are strongly attracted while the
current passes. The magnetic adhesion transmits the rotary motion of
the axle to shaft A, on which the whole apparatus is mounted. The
current which circulates at same time around the electro-magnet C, C,
also causes two sleeves or barrels F, F, fitted loosely on shaft A, and
each provided with a soft iron disc to be attracted by the poles C, and
adhere firmly thereto, and so participate in the motion of shaft A. The
two chains H attached to the barrels thus become wound thereon,
whereby pulley K is raised, and the brake blocks are pressed against the
wheels with a gradually increasing force until they skid. On breaking
the electric current, the two barrels F, F, being no longer attracted by
the magnet C, again become loose on the shaft, allowing the two chains
to unwind and the two circular electro-magnets L, L, falling away at
same from the axle the brakes are taken off.
Commutators placed on the locomotive and also in the guards' van
enable the driver or other person in charge of the train to instantaneously
apply or take off the whole of the brakes. The brakes may also be
worked by hand without the aid of electricity, for which purpose the
outer ends of the barrels F, F, and the bosses of the circular electro-
magnets L, L, are made in the form of clutches. Two forked push rods
P¹, P³, jointed together at the one extremity serve to couple both barrels
Fat once with the shaft A. The pressure of these rods P being applied
obliquely also swings the whole apparatus towards the wheel axle Q and
presses L, L, against it with sufficient force to transmit rotary motion to
shaft A and barrels F, and so wind the chains H, H, and apply the
brakes as quickly as when electricity is used.
In Figure 1 the rods P¹, P³, are illustrated as being operated by the
ordinary hand wheel and screw to show that the improved apparatus
may be applied to the present service.
Figure 6 shows another arrangement for applying the brakes without
the aid of electricity. The two rods P¹, P³, are operated by right and
left-handed screw shaft 4, and the brakes are applied by means of a hand
wheel on a shaft 5 gearing with screw shaft 4, which couples the sleeves

page_text: F, F, with the bosses of friction wheels similar to the circular electro-
magnets L, L, before described.
Other means of applying the brakes by the aid of electricity differing
from the arrangement first herein described may be advantageously
applied in certain cases, more particularly when as an additional safe-
guard it is desired that the brakes should be applied on the interruption
of the electric current. One of these arrangements is illustrated in
Figures 7 and 8.
The circular electro-magnets L, L, before referred to are replaced by
ordinary friction wheels keyed eccentrically on the shaft A. Two soft
iron armatures 2, 2, are slipped on the shaft on either side of the friction
wheel, which armatures embrace the four poles of the two fixed electro-
magnets 3, 3. While the current is not passing through the electro-
magnets 3 the two friction wheels bear on axle Q either by their own
weight or by the pressure of a spring, whereby rotary motion is imparted
to said wheels. Owing to their eccentricity shaft A is caused to swing
to and fro, and thus transmit a to-and-fro motion to the two armatures
2, 2, which rub against the four poles of the electro-magnets 3, 3.
Immediately however that the electric current is caused to pass through
the latter the two armatures are firmly held in such position as to
prevent the rotation of the axle being transmitted to the wheels 1.
To apply the brakes it is simply necessary to interrupt the current
through magnets 3, 3, and pass it through the electro-magnet with four
poles C, C.
Another mode of operating is shown in Figures 10 and 11, in which
the two circular electro-magnets are retained, and two permanent
magnets 4, 4, are applied tangential thereto with the same poles together.
The effect of this is that when the current circulates through the electro-
magnets the magnetic attraction is neutralized, the circular electro-
magnet is pressed against the wheel axle by a weight or spring, and
rotary motion is transmitted thereto from the axle. When on the other
hand the current does not circulate the permanent magnet, which is
provided with soft iron appendages 5, 5, holds the circular electro-
magnet back from the axle as in the preceding arrangement.
Another arrangement is represented in Figure 9 in which the two
electro-magnets are replaced by simple eccentric friction wheels as in

page_text: Figures 7 and 8, and instead of having two armatures loose on the shaft A
one only is used sliding with friction against the poles of two bobbins 3, 3,
fixed at the two ends of permanent electro-magnet 4, and forming pro-
longations of its poles. When the current is not not circulating through
the two bobbins 3, 3, the permanent magnet 4 is free to attract the
sliding armature and hold shaft A, and consequently the two friction
wheels away from the wheel axle. The transmission of motion from the
axle is thus prevented. When the current is passed through the two
bobbins 3, 3, so as to neutralize the attraction of the permanent magnet
for the sliding armature the two eccentric friction wheels are released
and receive motion from the axle. In order to apply the brakes in this
arrangement the current is caused to pass both in the bobbins 3, 3, and
in the electro-magnet C, C, Figure 1, which operates the chain barrels.
The battery is placed in one of the carriages, and the conducting
wire Y, Figure 14, leading from one of the poles of the battery, is con-
nected to one of the hanging supports S, Figure 2, by being soldered to
a sufficient extent of its surface to overcome resistance. The current
passes from this support to a brass journal L insulated from shaft A. (see
Figures 2 and 5), from which journal the current passes through a wire
to the coil of the circular electro-magnet L, and after traversing the
whole of its coils passes by an insulated wire contained in a groove in
shaft A (see Figure 15) to the four-poled electro-magnet C, C, after
traversing the coils of which it passes by similar means to the other
circular electro-magnet, and thence back to the other pole of the
battery.'
The conducting wires which couple adjoining carriages are connected
in the manner shown in Figures 12, 13, and 14 by means of the clamp
M', consisting of two jaws fixed outside the carriage, within each of
which is stretched a series of wires F¹ attached at top and bottom of
each jaw, and thus forming a series of flexible contacts. The two jaws
are pressed together by a spring, and each of these wires bears on a
link N¹ inserted between the jaws. The link N' is connected metalically
with the wire Y extending along the next carriage and connected to a
similar clamp to M¹ thereon. The wires F¹ bearing with elastic pressure
against link N¹ constitute a series of contacts highly favorable to the
passage of the current.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 7th January 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of July, in the year of our. Lord
One thousand eight hundred and seventy-three, in the thirty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Alexander Melville Clark, Her special licence
that I, the said Alexander Melville Clark, my executors, administrators,
and assigns, or such others as I, the said Alexander Melville Clark,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter,
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN RAILWAY BRAKES," a communication to me from abroad
by François Ferdinand Auguste Achard, of Paris, France, upon
the condition (amongst others) that I, the said Alexander Melville
Clark, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alexander Melville Clark, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
three Sheets of Drawings and to the letters and figures marked thereon
(that is to say) :-

page_text: which shows a longitudinal sectional elevation, and Figure 2 a plan of a
railway carriage framing with the improved brake applied.
The whole apparatus is hung like a pendulum from the carriage
framing on gudgeons P, P, one of which only is visible in the sectional
elevation, Figure 1.
At the middle of a horizontal shaft A, Figure 2, is keyed horizontally
an electro-magnet having four poles C, C, seen also detached in Figures
3 and 4, and at each end of the said shaft is placed a circular electro-
magnet L, L, Figures 2 and 5. These two magnets L, L, hang so near
to the wheel axle Q that they are strongly attracted against it imme-
diately the current passes, and acting as friction wheels the magnetic
adhesion causes the rotary motion of the axle to be transmitted to
shaft A. The current which also circulates around the electro-magnet
C, C, at same time causes two barrels F, F, (fitted loosely on shaft A,
and each provider with a soft iron disc), to be attracted by the poles C,
and adhere firmly thereto so as to participate in the motion of shaft A,
whereby the two chains H attached to the barrels become wound thereon,
raising pulley K. and pressing the brake blocks against the wheels with
a gradually increasing force until they skid. When the electric current
is interrupted, the two barrels F, F, being no longer attracted by the
magnet C, again become loose on the shaft A and allow the two chains
to unwind, and the two circular electro-magnets L, L, at same time
falling away from the axle Q the brakes are thus taken off.
Commutators placed on the locomotive and also in the brake van or
other carriage enable the driver or other person in charge of the train to
instantaneously apply or take off the whole of the brakes. The brakes
may also be worked by hand without the aid of electricity, for which
purpose the outer ends of the barrels F, F, and the bosses of the circular
electro-magnets L, L, are made in the form of clutches. Two forked
push rods P1, P2, jointed together at the one extremity serve to couple
both barrels F at once with the shaft A. The pressure of these rods
P¹, P², being applied obliquely also swings the shaft towards the wheel
axle Q and presses the friction wheels L, L, against it with sufficient
force to transmit rotary motion to the shaft A, and so wind up the
chains H, H, on barrels F and apply the brakes as quickly as when ;
electricity is used.

page_text: In Figure 1 the rods P1, P2, are operated by the ordinary hand wheel*
and screw to show that the improved apparatus may be applied to
existing rolling stock.
Figure 6 shows another arrangement for applying the brakes without
the aid of electricity. The rods P1, P2, are operated by a right and left-
handed screw shaft 4, and the brakes are applied by means of a hand
wheel on a shaft 5 gearing with screw shaft 4, which couples the chain
barrels F, F, with the bosses of friction wheels similar to those L, L,
before described.
Other means of applying the brakes by the aid of electricity differing
from the arrangement first herein described. may be advantageously
applied in certain cases, more particularly when as an additional safe-
guard it is desired that the application of the brakes should take place
on the interruption of the electric current. A modification of this kind
is illustrated in Figures 7 and 8.
· The circular electro-magnets L, L, before referred to are replaced by
ordinary friction wheels 1 keyed eccentrically on the shaft A. Two soft
iron armatures 2, 2, are slipped on the shaft on either side of the friction
wheels, which armatures embrace the four poles of the two fixed electro-
magnets 3, 3. Whenever the current is not passing through the electro-
magnets 3 the two friction wheels 1, 1, are caused to bear against axle Q
either by their own weight or by the pressure of a spring, whereby
rotary motion is imparted to said wheels. Owing to their eccentricity
the shaft A is caused to swing to and fro, so that the two armatures 2, 2,
which move with the shaft rub against the four poles of the electro-
magnets 3, 3. Immediately the current passes through the latter the
two armatures are attracted and the wheels 1, 1, are held back from the
axle Q so as to prevent the transmission of motion to the shaft. The
remainder of the apparatus is the same as before described.
To apply the brakes it is simply necessary to interrupt the current
through magnets 3, 3, and pass it through the electro-magnet with four
poles C, C.
Another mode of operating is shown in Figures 10 and 11, in which
the two circular electro-magnets are retained, and two permanent
magnets 4, 4, are applied tangentially thereon with the same poles
together. The effect of this is that when the current circulates through

page_text: the electro-magnets the attraction of the permanent magnet is neutralized
and the said electro-magnets are pressed against the wheel axle by a
weight or spring and receive rotary motion therefrom. When on the other
hand the current does not circulate, the permanent magnet, which is
provided with soft iron appendages 5, 5, holds the circular electro-
magnet back from the axle as in the preceding arrangement.
Another arrangement is represented in Figure 9, in which the two
electro-magnets are replaced by simple eccentric friction wheels, as in
Figures 7 and 8, and instead of having two sliding armatures loose on
the shaft A one only is used sliding against the poles of two bobbins 3, 3,
fixed at the two ends of a permanent electro-magnet 4, and forming
prolongations of its poles. When the current is not circulating through
the two bobbins 3, 3, the permanent magnet 4 is free to attract the
sliding armature and hold shaft A, and consequently the two friction
wheels away from the wheel axle. The transmission of motion from the
axle is thus prevented, but immediately the current is passed through
the two bobbins 3, 3, so as to neutralize the attraction of the permanent
magnet for the sliding armature the two eccentric friction wheels fall
against the axle and receive motion therefrom. Thus in order to apply
the brakes in this arrangement the current is caused to pass both in the
bobbins 3, 3, and in the electro-magnet C, C, which is also employed in
this case to operate the chain barrels, as before described in Figure 1.
The battery is placed in one of the carriages, and the conducting
wire y, Figure 14, leading from one of the poles of the battery is con-
nected to one of the hanging supports S, Figure 2, by being soldered to
an extent of its surface sufficient to overcome resistance. The current
passes from this support to a bearing brass L insulated from shaft A (sec
Figures 2 and 5) by a fixed sleeve of insulating material, from which
bearing the current passes through a wire to the coil of the circular
electro-magnet L, and after traversing the whole of its coils passes by
an insulated wire contained in a groove in shaft A. (see Figure 15) to
the four-poled electro-magnet C, C, after traversing the coils of which
it passes by similar means to the other circular electro-magnet, and
thence back by the other bearing to the other pole of the battery.
The conducting wires which couple adjoining carriages are connected in
the manner shown in Figures 12, 13, and 14, by means of the device M',
consisting of two jaws fixed outside the carriage, within each of which
is stretched a series of wires F¹ attached at top and bottom of each jaw,

page_text: and thus forming a series of flexible contacts. The two jaws are pressed
together by a spring, and each of these wires bears on a link N¹ inserted
between the jaws and connected metallically with the wire y extending
along the next carriage and connected to a similar device thereon. The
wires F¹ bearing with elastic pressure against link N¹ bend round the
same, and thus constitute a series of contacts highly favorable to the
passage of the current.
Figures 16 and 17 show in elevation and plan an arrangement by
which the
pressure of the break blocks against the wheels is regulated
and limited, the brakes being alternately applied and released in a
manner which stops the train more effectually than with a continuous
application of the brakes. In this case the chain by which the brakes
are actuated is attached to a spring rod a, b, in such manner that under
a certain degree of tension the hook A¹ will be drawn down util a short
circuit is made at contact A², upon which (the current no longer passing
in the four-poled electro-magnet) the brakes are released. Immediately
afterwards as the strain on the chain slackens the contact at A2 is broken
and the brakes are again applied and then taken off, the operation of the
brakes being intermittent as before described.
Having described the nature of the Invention and the manner of per-
forming the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is,―
1st. Suspending the whole of the mechanism from the carriage
framing near the wheel axle, substantially as herein shown and described
and without necessitating a continuous transmission of motion thereto
whilst the train is running.
2nd. The circular electro-magnets arranged and applied for trans-
mitting rotary motion from the wheel axle to the shaft actuating the
brake gear, substantially as herein specified.
3rd. The employment of the wheel axle for the transmission of rotary
motion by magnetic attraction and adhesion, substantially as herein
specified.
4th. Passing the electric current through the hanging supports and
through insulated wires embedded in the shaft, substantially as set

page_text: 5th. The three arrangements of gear shown and described for utilising
the rotary motion of the wheels for applying the brakes as specified.
6th. The two arrangements herein shown and described for working
the brakes by hand without the aid of electricity.
7th. The employment with the said hand arrangements referred to in
clause 6 of the rotary motion of the wheel axle to apply the brakes,
substantially as specified.
8th. The means of alternately increasing and slackening the pressure
of the brakes, substantially as described and shown in Figures 16
and 17.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Seventh day of January,
in the year of our Lord One thousand eight hundred and
seventy-four.