IMPROVEMENTS IN RAILWAY AND OTHER BRAKES
Year: 1867

page_text: LETTERS PATENT to Alexander Melville Clark, of 58, Chancery Lane,
in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
RAILWAY AND OTHER BRAKES."-A communication from abroad by Désiré
Parfait Lefèvre and Louis Philippe Dorré, Engineer, both of 29, Boulevart
St. Martin, Paris.
Sealed the 28th April 1868, and dated the 5th November 1867.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark.
at the Office of the Commissioners of Patents, with his Petition, on the
5th November 1867.
I, ALEXANDER MELVILLE CLARK, of 58, Chancery Lane, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IMPROVE..
MENTS IN RAILWAY AND OTHER BRAKES," to be as follows:-
This Invention, which is illustrated in the accompanying Drawings, relates
to improvements in railway brake apparatus' operated by the aid of the
buffers.
Figure 1 shows a longitudinal vertical section of the lower framing of a
railway carriage with the improved brake apparatus applied; Figure 2, a
transverse vertical' section on line 3, 4, 5, 6, Figure 8, which is a plan of
same; the same letters apply to all three Figures.
One of the axles a carries a loose collar 6' having lugs, to which are con-
nected two rods c, c, jointed at one end of a balance lever arrangement
formed of twin rods d, d, pivoted' on a part e carried on the axle; the arms

page_text: of the balance levers are weighted at f.. The two branches g of the forked
bell-crank lever i, Figure 2, suspended from the framing at h work freely
in the groove of collar 6. Another lever ; placed in a horizontal position
bears on the lever arm i, it being mounted transversely thereto, on a
centre 1,. and provided at one end with a counterbalance k: This lever j is
prolonged at m, and carries a slide n, one face of which bears against the
cross bar o of framing, while the other face acts on an enlargement or stop p
formed on the draw bar q.. Behind the buffer and traction. spring r is placed
the brake lever s fixed on the horizontal brake shaft for operating the
brakes u, u, by means of rods and levers, as in ordinary.
The apparatus for applying and taking off the brakes is arranged as
follows:At the ends of the opposite buffer and traction spring are mounted
rods x, x, slotted at their ends.a¹, and operating the horizontal levers y, y,
pivoted at 2, z, which bear with or without initial pressure on the back of the
brake spring r, or on any fixed point of the traction bar q without impeding
the motion of the brake lever s. The stop p is placed so as not to prevent
the movement of the traction bar which works freely under the framing,
the spring also participating in such movement in both directions, the
distance between slide n and stop p being arranged to allow of sufficient
recoil to prevent the wear of the brake surfaces,, and keep the brake in
working order under all circumstances. The position of the pivots z, z, of
levers y, y, and also that of spring at its centre-and-extremities are arranged,
Ist, so as to offer sufficient resistance to the recoil of the spring under all
conditions of the line, and especially when descending inclines; 2ndly, so as
to regulate this resistance in case of need by the tension of the opposing spring
which acts on the rods x, x; and, 3rdly, so as not to offer any resistance to
the recoil of the spring r during the action of the brakes. This improved
brake acts by the pressure of the buffers at the will of the driver or brakesman
at the front of the train.. When out of gear the parts are all in the position.
shown in the Drawings. The lever ; rests on i, holding collar 6 in position
with the balance lever & lying along the axle, as seen in Figure 2; at the
other end of lever j the part n interposes between the cross piece.o and
stop p of traction bar q. On the vehicle being backed the spring r yields and
the brake traction bar is drawn inwards,, its stop. p abutting against the
slide n, the brakes being thus brought up to the wheels, but as pressure is
not applied the vehicle will freely move in the backward direction. Supposing
the brake carriage to be placed in a.train and to be turned in either direction,
the balance lever d, the rods c, and collar 6 of axle a will turn with the latter.
The effect of centrifugal force causes the balance weights f to rise at a given

page_text: speed, the collar o being displaced and drawn by the rod c towards the middle
of the axle, while the fork g pivotted at partaking in the same movement,
its crank arm i rising lifts at same time the lever j of slide n, when the latter
will fall; all the parts remain in this position and in gear while the train is
in motion, allowing of the free backward movement of the traction bar.
When the brakes in front are applied to stop the train the whole apparatus
first opposes its resistance, but as the front and rear pressures are almost equal
at the two ends of the carriage, added to that of the levors and spring r, and
as the lever arms y are made of proportionate length, the action of spring r
will cease at the limit of pressure which has been fixed, and where its counter-
pressure would become disadvantageous. The buffers thus recede carrying
the draw bar with them by the aid of the spring r, the stop on which bar
passes over the part n in its downward position; the pressure of the buffers is
thus utilized for applying the breaks u on the wheels whatever may be the
wear of the wheels and brakes. Hence it is unnecessary to regulate their
relative positions other than by determining the position of the slide n and
stop with regard to each other. On the brakes being applied the apparatus
is returned to position by the spring r, which reassumes its original position
immediately the pressure of the buffers ceases; this return to position is.
effected gradually and without shocks, but is at same time certain and
effective whatever may be the position of the brake. By making the levers y,
for example, in the proportion of two to one, the force of the pressure exercised
by them on the brake traction bar may amount to one half of the force
acting on spring r. If after the brake is placed in gear during the motion of
the train the latter should suddenly stop and operate the brakes, the apparatus,
will immediately disengage itself by the act of slacking and stopping, and it
is unnecessary to effect that purpose, which is a great advantage, especially
for manoeuvring and working inclines..
This apparatus may be applied to all hand brakes, and with the exception
that the traction and buffer rods require lengthening no change is required in
existing parts; it is however of advantage to increase the force of spring r as.
much as possible.
To sum up the advantages of the apparatus above detailed, 1st;. the improved
self-acting brake is simple and inexpensive, and requires no additional springs;
2ndly, it is readily thrown in or out of gear without shocks by the aid of the
two buffer springs which retain entire liberty of action; 8rdly, it utilizes the
pressure of the buffers and dispenses with the various regulating parts.
I reserve the right of applying these improvements to vehicles travelling on.
roads, and especially those drawn by road locomotives.

page_text: The chief features of the improvements in brakes are,-
1st. The application of a centrfugal regulator similar to those of steam
engines, one example being shown in red lines, Figure 2.
2ndly. In this apparatus the action is produced by an improved combination
of levers and weights without the aid of springs.
3rdly. That the application and removal of the brakes is obtained without
the aid of additional springs by the improved arrangement of levers before
described.
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 4th May 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of November, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first 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 AND OTHER BRAKES," a communication to me from
abroad by Désiré Parfait Lefévre and Louis Philippe Dorré, Engineer, both
of 29, Boulevart St. Martin, Paris, 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

page_text: to be performed, to be particularly described and, ascertained in and by the
following statement, reference being had to the two Sheets of Drawings:
hereunto annexed, and to the letters and figures marked thereon (that is to.
say):-
:
This Invention which is illustrated in the accompanying Drawings relates
chiefly to improvements in railway brake apparatus operated by the aid of the
buffers.
:
Figure 1 shows à longitudinal vertical section of the lower framing of a.
railway carriage with the improved brake apparatus applied; Figure 2, a
transverse vertical section on line 3, 4, 5, 6, Figure 3, which is a plan of:
same; while Figures 4, 5, and 6, show details herein-after described. The
same letters apply to all the Figures.
One of the axles a carries a loose collar 6 having Ings, to which are con-'
nected four rods c, c, jointed to a centrifugal regulator formed of twin rods d, d,i
pivoted on a part e carried on the axle, the arms of the regulator being:
weighted at f. The two branches g of a forked bell-cranked lever & suspended:
from the framing at h work freely in the groove of collar b. The two
arms, g, i, may be united near the fulcrum k. Another lever j placed in a
nearly horizontal position in a plane with the longitudinal axis of the
carriage bears constantly on the lever arm i. The lever is mounted on a
fulcrum at 1, and may be provided at one end with a counterbalance k, its}
other end m carries a slide n, one face of which bears against the cross bar o
of framing, while the other face acts on an enlargement or stop p formed on
the draw bar q. Behind the buffer and traction spring r is placed the brake:
lever s fixed on the horizontal brake shaft t for operating the brakes u, u, by
means of rods and levers, as in ordinary.
The apparatus for applying, and taking off. the brakes is arranged as:
follows: At the ends of the opposite buffer and traction spring are
mounted rods a, a, operating the horizontal levers y, y, pivotted at 2, %, which
bear with or without initial pressure either on brake lever s or on any fixed
point of the traction bar 9 without impeding the motion of the said brake
lever s. The stop p is placed so as not to prevent the movement of the
traction bar which works freely under the framing, the spring r also par-
ticipating in such movement in both directions, the: distance between slide n
and stop p being arranged to allow of sufficient recoil and prevent the wear of
the brake surfaces, and keep the brake in working order under all circum-
stances. The position of the pivots 2, 2, of levers y, y, and also that of the:
spring rat its centre and extremities are arranged, .1st, so as to offer a.
sufficient resistance to. the recoil of the spring under all conditions of thei

page_text: line, and especially when descending inclines; 2ndly, so as to regulate this
resistance in case of need by the tension of the spring and parts which act
on the rods x, x; and, 3rdly, so as not to offer any resistance to the recoil of
the spring r and the action of the brakes. I may also utilize the pressure of
the spring r to serve as additional brake power at the moment that this
pressure becomes negatived by the action of the various parts of the apparatus.
This object is attained in the following manner:-The lever j is connected to
one end of the rod c¹ jointed to the framing at A; this rod is slotted to allow
of the levers working freely as also of the movement of said rod c². Above
the slotted part of rod c¹ is mounted a hook B mortised to receive the lever s,
the nose of which hook is a little below and behind the point of intersection
of the horizontal levers. The apparatus A, B, C, is so arranged that the
hook may be raised to a level with the levers 9, 9, every time the part n is
brought under the stop p; and in order to provide for cases in which the
action of the parts is produced when running at a speed a little above that
required for applying the brakes, when the hook would only rise on a level
with the lower horizontal lever, I provide said hook with a nib at one end
which acts on the upper horizontal lever so as to cause them to move simul-
taneously. The part B may be replaced by a double slotted bar, if desired,
or any other arrangement may be adopted in lieu of A, B, C, suitably adapted
to the purpose, whereby to regulate the position of the levers when the brake
is applied or after the recoil of the movable spring and the parts connected
therewith. The lever C may also be made of other form, and the recoil of
the spring be utilized for bringing a hook or catch into gear with the
levers y, y, acting in a similar manner to that above described.
In theory the power of the brake at the upper end of the locking lever s
may be expressed by the two following formulae :-
1st. Pu=P-R.
Pu, power required.
2nd. R=(Ai+b-P
A, recoil of the draw bar.
P, pressure of the buffers at each end i, elasticity of spring v in pounds.
of the carriage.
1L, lever arms y, y.
b, initial pressure of spring v in pounds.
R, resistance exerted by levers y, Y.
Thus the problem is reduced to that of giving R as required either a
positive or negative value. Further, if the manoeuvring at stations and moving
of trains with the engine in rear are liable in backing to produce pressure on
the buffers, which might partially operate the brakes, the apparatus A, B, C,
may be dispensed with. In this case the levers y, y, would be placed between

page_text: would be thus utilized. In some cases it might be of advantage to act on
part n by hand in order to apply or take off the brake by lowering or raising
said part n. This twofold result may be produced in various ways, and
among others by the aid of a forked lever one or other end of which is
connected to the bell-crank lever for imparting the motion desired. This
forked lever is operated either by a handle within reach of persons inside or
outside the carriage, or by means of a hand brake apparatus which may be
This improved brake acts by the pressure of the buffers at the will of the
driver or brakesman at the front of the train. When out of gear the parts
are all in the position shown in the Drawings; the lever j rests on i holding
collar 6 in position with the balance lever d lying along the axle, as seen in
Figure 2, at the other end of the lever j; the part n interposes between the
cross frame o and stop p of traction bar q while the catch B is depressed.
On the vehicle being backed the spring r yields, and the brake traction bar is
drawn inwards, its stop p abutting against the slide n and the levers y, y,
freely moving the brakes are thus brought up to the wheels, but as pressure
is not applied the vehicle will freely move in the backward direction.
Supposing the brake carriage to be placed in a train and to be turned in
either direction, the balance lever d, the rods c, and collar 6 of axle a will
turn with the latter. The effect of centrifugal force causes the balance
weights f to rise at a given speed, the collar 6 being displaced and drawn by
the rod c towards the middle of the axle, so as to suspend the balls of the
regulator, while the fork g pivotted at h partaking in the same movement its
crank arm i in rising lifts at same time the lever j of slide n, when the latter-
will fall while the hook B rises on a level with levers y, y. All the parts
remain in this position and in gear while the train is in motion, allowing of
the free backward movement of the traction bar. When the brakes in front
are applied to stop the train the whole apparatus first opposes its resistance,
but as the front and rear pressures are almost equal at the two ends of the
carriage added to that of the levers and spring r; and as the lever arms y are
made of proportionate length, the resistance of spring will cease and become
converted into auxiliary power at the limit of pressure which has been fixed
and where its counterpressure would become disadvantageous. The buffers
thus recede carrying the draw bar with them by the aid of the spring r; the
stop on which bar passes over the part n in its downward position, the
pressure of the buffers at each end is thus utilized for applying the brakės u

page_text: on the wheels, whatever may be the wear of the wheels and brakes. Hence it
is unnecessary to regulate their respective positions other than by determining
the position of the slide n and stop with regard to each other. On the brakes
being applied the apparatus is returned to position by the spring r, which
reassumes its original position immediately the pressure of the buffers ceases.
This return to position is effected gradually and without shocks, but is at same.
time certain and effective whatever may be the position of the brake. By
making the levers y, for example, in the proportion of 2 to 1, the force of the
pressure exerted by them on the brake traction bar may amount to one-half
of the force acting on spring r, and as the springs freely develope their
elasticity in both directions, all shocks are effectually prevented or neutralized.
If after the brake is placed in gear during the motion of the train the latter
should suddenly stop without applying the brakes, the apparatus will imme-
diately disengage itself by the act of slacking and stopping, and it is
unnecessary to effect that purpose, which is a great advantage, especially for
manoeuvring and working on inclines. This apparatus may be applied to
all hand brakes and, except in exceptional cases, no change is required in.
existing parts.
To sum up the advantages of the apparatus above detailed, 1st, the
improved self-acting brake is simple, inexpensive, and requires no additional
springs; 2ndly, it is readily thrown in or out of gear without shocks by
the aid of the two buffer springs which retain entire liberty of action;
3rdly, it utilizes the pressure of the buffers at one end of the carriage, and a
portion of that of the other end, and dispenses with the various regulating
parts.
The apparatus may also be applied in duplicate in the same carriage by
making both the buffer springs moveable, and adapting the parts thereto.
I reserve the right of applying these improvements to vehicles travelling.
on roads, and especially those drawn by road locomotives.
Having described the nature of this 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,-
First. The application in this improved system of brake of a centrifugal
regulator similar to those of steam engines, the form of which may be varied
aś desired as and' for the purposes described.
Secondly. The special arrangement of levers of this. Invention to be used as
a-substitute for springs. for applying the power in the manner described and
as illustrated in the accompanying. Drawings.
Thirdly. The arrangement of levers y, y, for taking off or applying the

page_text: brake power without the aid of additional springs, all in the manner shown
and described.
Fourthly. I claim the arrangement of parts B, C, Figures 4, 5, and 6, for
imparting increased power to the brakes by utilizing the pressure on the
buffers opposed to the brake in the manner described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto
set my hand and seal, this Fourth day of May, in the year of our
Lord One thousand eight hundred and sixty-eight..