IMPROVEMENTS IN BRAKES
Year: 1878

page_text: LETTERS PATENT to William Caldwell, of Tiverton, in the County of Devon,
for the Invention of "IMPROVEMENTS IN BRAKES."
Sealed the 20th September 1878, and dated the 23rd March 1878.
PROVISIONAL SPECIFICATION left by the said William Caldwell at the
Office of the Commissioners of Patents on the 23rd March 1878.
"
WILLIAM CALDWELL, of Tiverton, in the County of Devon. « IMPROVEMENTS
IN BRAKES,"
This Invention relates to improvements in railway breaks, and when fitted as an
atmospheric break, may be broadly described as follows:-On one of the revolving
axles of the vehicle to which my break is fitted I firmly fix a pinion with teeth,
preferably at an angle with its axial line, and in gear always with a wheel about 5
times its diameter, running loose on a cranked shaft, carried in the bearings of
brackets depending from the body frame, which wheel consequently always revolves
when the carriage or vehicle is in motion. This cranked shaft carries also a sliding
clutch with pins or nipples on it to take into oblong concentric slots in the before-
mentioned wheel when it is required to put the break in action. A double-action
air pump, of bellows, cylinder, or other form is actuated by a connecting rod from
this cranked shaft, and delivers air under pressure into a receiver of bellows form,
though a cylinder with piston or other equivalent device may be used. One of the
outside plutes or leaves of this second bellows carries a short lever in connection by
means of a rod with a longer lever keyed to the centre of a horizontal shaft running
from side to side and supported in brackets a short distance below the frame of the
vehicle, and each of the outer ends of this shaft has a short depending lever con-
nected through rods direct to the break blocks. Another smaller bellows or equivalent
device is arranged under the vehicle preferably near to the first-named sliding clutch,
and is fitted with a weight whose tendency is at all times to drive out any air the
said bellows may contain, and to close them. The bellows is, by piping, in connection
with an air pump worked by hand from the foot plate of the engine, by the driver
D011

page_text: or stoker, who can thus fill it with air, or empty it, as desired. This smaller bellows
is connected by a system of adjustable levers with a valve to open or close an aper-
ture in a tube in connection with the receiver and air pump before mentioned, and to
regulate the pressure in the receiver in exact proportion to the weight of the vehicle,
and by other levers with the sliding clutch by which the latter is thrown in or out
of action with the loose wheel on the crank shaft.
Each vehicle has a length of piping running under its frame from end to end, and
in its centre the ends terminating in a flexible portion, say, of india-rubber and a
flange. The flange at one or both ends of the carriage is provided with spring clips,
which can be sprung open when the flange of a neighbouring vehicle is pressed upon
them, and then close in and hold the two flanges together, by which the union of
the pipe of two carriages is readily made.
An apparatus to compensate for the wear of the break blocks is fitted to the
under side of the movable plate or cover of the receiver, and consists of a depending
forked bridle, the lower onds of which carry a small cross head which slides on the
lower end, and between two collars of a vertical rod with teeth on one of its faces,
the upper end of this rod being guided, when in motion, by passing through a boss
forming part of a depending bracket attached to the frame of the receiver; the
frame also carries a spring pawl which engages into one or other of the before-
mentioned teeth. As the break blocks become worn away, the bridle raises the
toothed rod higher and higher, and is kept in position ready for action by the pawl
taking into one of the teeth of the rod.
Each vehicle is fitted with a hand lover to keep the clutch free and the break out
of action during the process of shunting, and the air or exhausting pump can be
driven by friction gearing if desired.
When it is desired to fit my apparatus as a vacuum break, it is only necessary to
arrange the air pump to exhaust the receiver instead of to fill it with air, and also
to reverse the regulating valve, when, by a lever attached to the moving cover the
breaks can be applied as before.
In its normal stato (i.e., when tho vehicle is travelling) the smaller bellows is
kept charged with air from the pump on the engine, the tube leading to the receiver
is open by the valve controlling its opening being off its seat, and the clutch and
the crank shaft are stationary by the former being out of gear with the loose
wheel revolving by the onward movement of the vehicle, and supposing it being
required to apply the breaks, the action is as follows:-The driver or stoker
opens a cock or valve in the pipe, between the pump on the engine and the
sinaller bellows, thus allowing the air to escape, and the weight connected to
the latter expels the air they contained, puts the clutch on the cranked shaft
in gear with the wheel running loose on it, and closes by its valve the tube
leading to the receiver, the cranked shaft now revolves, and by its connecting
rod actuates the double-acting bellows or air pump, the receiver becomes charged
with compressed air in consequence of its being imprisoned by the closing of the
regulating valve and its outside leaf or plate (if in bellows form) being put in motion,
and under pressure conveys it by its own leverage to that of the breaks by which
they are almost instantly put in action.
It will be seen from the above that the greater the speed of the vehicle, the more
promptly will the breaks be put on.
I have described the break block as being connected to rods attached to short
levers carried on a shaft running across the carriage supported in brackets from the
under side of the frame, a longer lever in the centre of the said shaft being connected
by a rod to the lever arm of the moving cover of the compressed air or vacuum
vessel, as the case may be.
In this arrangement the break block which has worn the least comes into action
and breaks its wheel earlier, and with it a greater amount of bite than the blocks
of the other wheels. Now, to equalize the pressure of all the breaks upon their
respective wheels, I place a short lever at each end of the above-mentioned cross
shaft as before, but one of them with its end directed upwards and the other down-

page_text: wards, in the case of a six-wheeled carriage, and each carrying at its extremity a
small double-ended lever pivoted on it, one of the free ends of this lever being
connected by a rod to the break block or blocks of one wheel, while the other
one is connected in a similar manner to the blocks of an adjoining wheel, the
pivot of this double-ended lever being put in motion by the rod from the receiver
brings the breaks into action and with an equal pressure on each block, as one
cannot come into action without the other.
The cross shaft or shafts, the number of which depend upon the number of breaks
to be applied, has at its centre a short lever connected by a rod to a similar lever
on a neighbouring cross shaft which connects and puts into action all the breaks
simultaneously.
When it is desired to fit a single vehicle with break power, the hand pump
(which in the case of a train of carriages is preferably placed on the engine)
may be dispensed with, and also the small bellows attached to same, and the valve
which opens or closes the aperture in the tube leading to the receiver may be kept
off its seat by a chain or rod attached at its lower end to the weight which governs
the descent of the said valve, the upper end of this chain or rod being passed over a
hook or secured in any simple way in any part or compartment of the vehicle. On
the release of this chain the weight falls, the sliding clutch is thrown in gear, the
valve closes the tube, and the break is applied as before.
In the case of a train fitted with either of my breaks in a continuous manner
becoming accidentally separated at any part of its length, the rupture of the central
pipe would allow the air to escape from it, and so from all the smaller weighted
bellows, and the whole of the breaks would be instantly applied. One or more
branch pipes from the central pipe may be carried into any compartment of the
train with a tap or valve at its end, by opening which the breaks would be brought
into action.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Caldwell in the Great Seal Patent Office on the 23rd Septem-
ber 1878.
WILLIAM CALDWELL, of Tiverton, in the County of Devon.
BRAKES."
"IMPROVEMENTS IN
This Invention relates to improvements in brakes, and will be clearly understood
by the following description, with reference to the annexed Drawings.
Figures 1 and 2, Sheet 1, show in elevation and plan the brake fitted as an
atmospheric compressed air brake. On one of the revolving axles A of the vehicle
to which my brako is fitted I firmly fix a pinion B with teeth, preferably at an
angle with its axial line, as shown, and in gear always with a wheel C, about 5
times its diameter, running loose on a cranked shaft D, carried in the bearings or
brackets E, E, which are bolted to a suitable frame E', supported on the axle boxes.
The wheel C consequently always revolves when the carriage or vehicle is in
motion. The cranked shaft D carrics also a sliding clutch F with pins or
nipples G, G, on it to take into oblong concentric slots H, H, in the before-
mentioned wheel C when it is required to put the brake in action. A double-
acting air pump I of bellows, cylinder, or other form, but shown in bellows form in
the Drawings hereunto annexed, is actuated by a connecting rod J from the
cranked shaft D, and delivers air under pressure through the valves K and pipe L
into a receiver M of bellows form, though a cylinder with piston or other equiva-
lent device may be used in lieu of the receiver M. One of the outside plates or
leaves N of this second bellows carries a short lever O in connection, by means of a
rod P with a longer lever Q, keyed to a horizontal shaft R, running from side to
side, and supported on the frame that carries the brackets E a short distance below
the frame of the vehicle, and each of the outer ends of this shaft R has a short
depending lever S connected through rods T direct to the brake blocks U. Another
smaller bellows V or equivalent device is arranged under the vehicle, preferably
near to the first-named sliding clutch, and is fitted with a weight W, whose
tendency is at all times to drive out any air the said bellows may contain, and to
close them. The bellows V is by piping X in connection with an air pump Y,
which is worked by hand or otherwise from the foot plate of the engine by the
driver or stoker, who can thus fill it with air or empty it as desired. This smaller
bellows is connected by a system of adjustable levers, as shown, with a valve Z to
open or close an aperture in a tube a in connection by the pipe L with the receiver
and air pump before mentioned, and to regulate the pressure in the receiver M in
exact proportion to the weight of the vehicle, and by other levers b with the sliding
clutch F, by which the latter is thrown in and out of action with the loose wheel Č
on the crank shaft D.
Each vehicle has a length of piping c running under its fraine from end to end,
and in its centre, the ends terminating in a flexible portion d, say of india-rubber,
and a flange e. The flange e at one or both ends of the carriage is provided with
spring clips f, which can be sprung open when the flange of a neighbouring vehicle
is pressed upon them, and then close in and hold the two flanges together, by which
the union of the pipe of two carriages is readily made.
Figures 3 and 4, Sheet 3, show on an enlarged scale a side and end view of the
flanges e forming the coupling.
It will be seen that each flange of the coupling is provided with a short piece of
piping g, forming a kind of stem, with annular serrations upon its outer face,
into which the flexible portion d takes by contraction when passed over the end
of the pipe in the act of making a joint.
Figure 5 is a detached side view of the governing bellows V, and the levers for
closing the valve Z, and throwing the sliding clutch F in and out of gear.

page_text: An apparatus to compensate for the wear of the break blocks is shown in
Figure 1, and in detail in Figures 6 and 7. It is fitted to the under side of the
movable plate or cover N of the receiver M, and consists of a depending forked
bridle, the lower ends of which carry a small cross head j, which slides on the
lower end and between two collars of a vertical rod k with teeth l on one of its
faces, the upper end of this rod being guided when in motion by passing through
a boss m, forming part of a depending bracket n attached to the frame of the
receiver M. The frame also carries a spring pawl p, which engages into one or
other of the before-mentioned teeth. As the break blocks become worn away the
bridle raises the toothed rod higher and higher, and it is kept in position ready
for action by the pawl taking into one of the teeth of the rod.
Each vehicle is fitted with a hand lever g to keep the clutch free and the break
out of action during the process of shunting, and the air or exhausting pump I
can be driven by friction gearing if desired. The pump I is fitted to act either
as an air pressure pump or an exhausting pump, according as the break is fitted as
an atmospheric compressed air or as a vacuum brake.
When it is desired to fit my apparatus as a vacuum break it is only necessary
to arrange the air pump I to exhaust the receiver instead of to fill it with air and
to reverse the action of the regulating valves Z, when by the lever O attached to
the moving cover N the breaks can be applied as before.
Figure 8 shows a similar view to Figure 5 of the governing bellows, its levers,
and valve, with the exception that the valve Z in the tube a is shown in Figure 8
as opening inwards to suit the vacuum arrangement, while in Figure 5 the
valve Z is shown as opening outwards to suit the atmospheric compressed air
arrangement.
.
The air pump I in bellows form is shown in section in Figure 9. Figure 10
shows the apparatus fitted as a vacuum brake. Figure 11 is a section through the
vacuum chamber M which takes the place of the receiver used in the atmospheric
compressed air arrangement.
In the normal state of the brake (i.c., when the vehicle is travelling) the smaller
bellows V is kept charged with air by means of the pipe c from the pump Y on
the engine; the tube a leading to the receiver M is open by the valve Z controlling
its opening, being off its seat, and the clutch Fand the crank shaft D are stationary
by the former being out of gear with the loose wheel e revolving by the onward
movement of the vehicle; and supposing it being required to apply the brakes, the
action is as follows:-The driver or stoker opens the cock or valve r in a passage,
in this case forming part of the pump Y, and communicating with the pipe c between
the pump Y on the engine and the smaller bellows V, thus allowing the air to escape,
and the weight W expels the air the bellows V contained, puts the clutch F on the
countershaft D in gear with the wheel C running loose on it, and closes by its
valve Z the tube a leading to the receiver M. The crank shaft D now revolves,
and, by its connecting rod J, actuates the double-acting bellows or air pump I, the
receiver becomes charged with compressed air in consequence of its being imprisoned
by the closing of the regulating valve Z, and its outside leaf or plate N (when in
bellows form) being put in motion under pressure, conveys the said pressure by its
own lever to that of the brakes, by which they are almost instantly put in
action.
I have described the brake block as being connected to rods attached to short
levers carried on a shaft running across the carriage, supported in brackets from the
under side of the carriage fraime, or on a frame attached to the axle boxes, a longer
lever on the said shaft being, connected by a rod to the lever arm of the moving
cover of the compressed air or vacuum vessel, as the case may be.
In this arrangement, the brake block which has worn the least comes into action
and brakes its wheel earlier and with a greater amount of bite than the blocks of
the other wheels. Now to eqalize the pressure of all the brakes upon their respec-
tive wheels, I place a short lever at each end of the above-mentioned cross shaft,
as before, each lever carrying at its extremity a small double-ended lever pivotted

page_text: on it, one of the free ends of this lever being connected by a rod to the break block
or blocks of one wheel, while the other end is connected in a similar inanner to the
blocks of an adjoining wheel. The pivot of this double-ended lever being put in
motion by the rod from the receiver, brings the breaks into action and with an
equal pressure on each block, as one cannot come into action without the other.
The cross shaft or shafts, the number of which depends upon the number of
breaks to be applied, has on it a short lever connected by a rod to a similar lever
on the neighbouring cross shaft, which connects and puts into action all the breaks
simultaneously.
When it is desired to fit a single vehicle with break power, the hand pump Y
(which, in the case of a train of carriages, is preferably placed on the engine) may
be dispensed with, and also the small bellows attached to same, and the valve which
opens or closes the aperture in the tube leading to the receiver may be kept off its
seat by a chain y or a rod attached at its lower end to the weight which governs the
descents of the said valve, the upper end of this chain or rod being passed over a
hook or secured in any simple way in any part or compartiment of the vehicle. Ou
the release of this chain, the weight falls, the sliding clutch is thrown in gear, the
valve closes the tube, and the break is applied as before. The chain is shown in
Figures 1, 5, and 8.
In the case of a train fitted with either of my breaks in a continuous manner
becoming accidentally separated at any part of its length, the rupture of the central
pipe c would allow the air to escape from it and so from all the smaller weighted
bellows, and the whole of the breaks would be instantly applied. One or more
branch pipes from the central pipe c may be carried into any compartment of the
train with a tap c, as shown in Figure 1, or valve at its end, by opening which, the
breaks would be brought into action.
Figure 12 shows a manner of carrying out my Invention, by which the air
pump I is dispensed with, and the air condensed or compressed by the cam A' of
suitable form on the shaft D acting on the bell crank E', which, by lifting the bottom
leaf of the combined compressor and air vessel I, compresses the air in its upper
compartment J', thus causing the upper leaf N to rise, and, through the lever O and
the link P connected to the lever Q, to bring the brakes into action, as before
described. .
Instead of the compressing portion of I being single-acting as shown, I sometimes
make it in double-action form, in which case it would be actuated by a crank.
The apparatus thus simplified is also convertible into a vacuum brake by the
reversal of the action of the regulating valve Z, and of the relative position of the
air vessel and receiver.
To equalize the pressure of all the brakes upon their respective wheels, 1 place a
short lever S at each end of the cross shaft R, each short lever carrying a small
double-ended lever R¹ pivoted on it.
One of the free ends R¹ of this double-ended lever is connected by a rod T to
the brake block of one wheel, while the other end R is connected by another rod
T' to the break block of the next wheel on the same side of the vehicle. Thus the
pivot S¹ of this double-ended lever, being put in motion by the rod or link P from
the receiver, brings the breaks into action with an equal pressure on each wheel,
inasmuch as one of them cannot come into action without the other.
The pump on the engine, shown as worked by hand, is fitted with a gauge u to
indicate the pressure of air within the pipe c, and a whistle v arranged to sound
when the pressure of the air within the pipe c falls below that required to keep the
governing bellows distended and the valve Z off its seat.
And having now described the nature of my said Invention and in what manner
the same is to be performed, I declare that I claim as my improvements in
brakes,―
First. The general arrangement and combination of parts herein-before described
and substantially as shown in Figures 1 2 3 4 5 6 7 and 9 of the annexed

page_text: Secondly. The modified arrangement herein-before described, and substantially
as shown in Figures 8, 10, and 11 of the annexed Drawings, and
Thirdly. The modification shown in Figure 12, acting as and for the purposes set
forth.
Fourthly. I claim the forked bridle arrangement herein-before described, and
substantially as shown in the annexed Drawings, for compensating for the wear of
the brake blocks.
In witness whereof, I, the said William Caldwell, have hereunto set my hand
and seal, this Nineteenth day of September, One thousand eight hundred
and seventy-eight.
W. CALDWELL. (L.S.)