IMPROVEMENTS IN APPARATUS FOR OR CONNECTED WITH MOTIVE-POWER ENGINES WORKED BY COMPRESSED AIR OR OTHER ELASTIC FLUID FOR THE PROPULSION OF TRAMWAY CARS OR OTHER VEHICLES
Year: 1877

page_text: LETTERS PATENT to Robert Hardie, of Govan, in the County of Lanark, En-
gineer, and John James, Bachelor of Science and Engineer, Edinburgh, in
the County of Mid Lothian, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR OR CONNECTED WITH MOTIVE-POWER ENGINES WORKED BY
COMPRESSED AIR OR OTHER ELASTIC FLUID FOR THE PROPULSION OF TRAMWAY
CARS OR OTHER VEHICLES,”
Sealed the 21st August 1877, and dated the 11th April 1877.
PROVISIONAL SPECIFICATION left by the said Robert Hardie and Johu
James at the Office of the Commissioners of Patents on the 11th April 1877.
ROBERT HARDIE, of Govan, in the County of Lanark, Engineer, and JOHN
JAMES, Bachelor of Science and Engineer, Edinburgh, in the County of Mid Lothian.
"IMPROVEMENTS IN APPARATUS FOR OR CONNECTED WITH MOTIVE-POWER ENGINES
WORKED BY COMPRESSED AIR OR OTHER ELASTIC FLUID FOR THE PROPULSION
OF TRAMWAY CARS OR OTHER VEHICLES."
This Invention has for its object, and mainly consists in contriving, arranging,
and combining together certain new or improved apparatus or mechanism, or com-
bination of these, for the more efficient and economical use of compressed air or
other elastic fluid, as a means of or engines for propelling tramway cars and other
vehicles, or for railway carriages or waggons, and many other cases (where this
system of propulsion is preferable to steam), as for the motive engines or vehicles
in tunnels, mines, and ferry boats.
Under these improvements the general construction of the engines may be of
the ordinary types of high-pressure steam or compressed air expansion engines used
for propulsion purposes, with two or more cylinders having the piston and rods
acting on their cranks and shaft, preferably at right angles, for two cylinders ranged
horizontally, at an angle or vertically, as found suitable for the particular circum-
stances or purposes to which the engines are to be applied, all adjacent to their
compressed air or motive-working fluid receivers, which for the primary purpose of
propelling tramway cars night be made of any convenient size or length and
number, joined together by branch pipes, and disposed transversely or longitudinally
below the carriage or seats, or otherwise, where there is convenient space on the

page_text: car or the traction carriage when this is used separate from the cars to draw
them.
The traction carriage or the tramway car to be used may be of any convenient
construction and form required or employed for other arrangements and modes of
propulsion, the side frames being preferably made deep enough to carry the com-
pressed air vessels, in recesses through them, secured by straps and wood blocks to
prevent motion or frictional wear. When the car or vehicle is carried on two pairs
of wheels, and their axles or shafts placed as usual at from 3 feet 6 inches to 6 feet
apart under the middle of the frame for stability and ease in turning the curves of
the rails without steering gear, it is preferred to place the cylinders or engines
between the axles, securing them to and between the main side frames carrying the
springs and axle boxes, and in a line with one of the axles as the crank shaft, having
their connecting rods directly connected to its cranks at right angles. The
wheels of this shaft arc, when preferred as for gradients, directly coupled to those
of the other shaft or axle by outside parallel-acting connecting rods, fitted on crank
pins fixed in the wheels at right angles to each other on the opposite sides. The
cylinders of the engine are provided with the usual admission and exhaust ports,
and their working pistons, piston rods, connecting rods, and guides, and with close
valve casing, and ordinary short slide valves with the exhaust chamber in the
middle, and transverse steam ports passing through the valve beyond the said
chamber and near each end of valve, with the expansion valves preferably of the
right and left cut-off screw kind, known as Meyer's, working on the back of the
slide valves, all as so far described without any of the special improvements forming
the essential subject of this Invention.
By one of the improvements of this Invention each half or part of the cut-off or
expansion valve is formed with a transverse oblong port through it near the outer
end, with a new or additional plate or block slide valve fitted to work on the back,
between and over these ports in the two cut-off valves, by a valve spindle working
out through a stuffing box in either end of casing, and with suitable hand gear
outside. When the valves of both cylinders work back to back in one casing, a
small central spindle may work both of these new central plate valves with a
narrow space and pressing springs between them.
The central or normal position of the new valves shall be neutral, but when
moved in one direction these valves shall partially or wholly cover the port in the
one end or part of the expansion valves, so that the acting pressure air or fluid will
not be admitted to that end of the cylinder; and when moved in the opposite
direction, they shall have the effect of rendering the expansion valves to some
extent inoperative, by admitting a small quantity of the compressed air into other
new passages formed in the expansion valves direct through the main slide valve
into the cylinder, even after the expansion valves have cut off the acting pressure
fluid, and so give less or greater power to and for starting the engines, according as
this valve is moved by a hand lever to any of its corresponding three positions;
theso inner ports of the cut-off valves being always covered by the new valve in its
normal or middle position.
By another improvement, automatic acting or suction valves may be fitted in
connection with the pistons opening to each end of the cylinders, so as to admit
atmospheric pressure to prevent the formation of a partial vacuum in the cylinders,
which would retard the working of the pistons, and otherwise enable the cylinders
to work as air-forcing pumps.
The piston rods are inade tubular to admit of the passage of air from the atmo-
sphere to these valves in the piston; and new escape or pressure-discharge valves
will also be fitted in the admission ports leading from the ends of the cylinder,
opening to the inside of the valve casing to relieve whatever excess of pressure may
accumulate within the cylinders above that within the casing, when the ordinary
slide valve is placed in mid-gear, with the usual admission and exhaust ports closed.
The cylinders will in this way be practically converted into pumps, atmospheric air
entering by the suction valves in the pistons to both ends of the cylinders, and

page_text: forced through the delivery valves into the valve casing, thus serving the purpose
of a brake and utilizing the retarding force to stop the car or retard its motion in
going down an incline, whenever the hand gear or link motion shuts the slide
valves. When these delivery valves for both cylinders are fitted opposite each
other near the ends of the valve casing, one long spiral spring or separato springs
on one spindle could be used.
By another improvement the right and left threaded screws of the two expansion
valve spindles aro mado alternate, so as to actuate their valvos as usual while being
turned in opposite directions by means of right and left worms or endless screws,
keyed on or forming part of the actuating or cut-off gear shaft, carried in boarings
at one end of the cylinders; these worms gearing into corresponding worm wheels
attached or fixed on the valvo spindle, the worm wheels also gearing into each other
as spur wheels, so that the whools boing moved together in opposite directions the
necessity for shoulders or collars upon the worm spindlo is obviated, there being no
end thrust on or tendency to screw itself out of gear with the wheels.
By another improvement a two-way cock or valve is fitted in one of the inlet
ports, so as to open or close the port leading to one end of the cylinder from the slide
valve, and in closing, open it to the exhaust chamber and pipe, and thus practically,
whon dosired, work the engines half power by one end of each cylinder and stroke
of the piston, the levers of the new taps or valves of both cylinders being con-
nected so as to be actuated by one hand lever. This arrangement may be used as
another or alternate moans to that described of making the cylinders double or single
acting.
By another improvement the engine is provided with a mechanical brake, con-
sisting of a hydraulic ram, acted upon by oil, glycerine, or other liquid which is not
easily frozen, under considerable pressure (preferably two cylinders with the oil
admitted between them), which shall press the brake blocks against all the wheels.
To release the brako, the pressure fluid acting on one side of the piston is made to
act on both sides after the supply is shut off, and springs ensure the release.
A small force pump may be used to return cach charge of oil made use of from
the acting cylinder to a vessel under a high pressure of air or other elastic fluid,
or that of a strong stoel spring.
Suitable hand gear and connexions to work all the said ordinary and new or
improved valves will be fitted at either or both ends of the car or vehicle, or in any
other suitable or convenient position; and also a pressure gauge fitted there or at
each end, with cocks and connecting tubes, all so as to indicate the pressure in
whatever vessel the gauge is put in communication with.
By another improvement the compressed air may be heated between the receiver
and valve casing by passing it through a very thin copper or other pipe, coiled or
undulating through a hot water or other heater, with as great a pressure within it
as that of the air within the heating pipe, so as to heat the air quickly through
the thin pipe without the risk of bursting it; which heater may be of any
convenient construction and shape to resist the pressure within and suit the space
available, heated by a coke or charcoal fire, or by gas or chemical flame heaters;
and the water in this heater may be made to circulate through a casing or jacketed
space round the cylinders of the engines to heat them and the air expanding within
them; or other ordinary means of heating the compressed air may be used.
The cylinders would be made large enough for the maximum power required to
ascend the greatest gradients on the line; the lesser powers being regulated by the
cut-off valves through their ordinary reversing and cut-off gear, or by the new arrange-
ment of ports and valves herein-before described, giving a single and double action;
and the cylinders would be fitted with pet or relief cocks and levers with rods
and handles convenient for the driver to work them so as to regulate or vary
their pumping effect, which cocks would also answer for lubricating the cylinders.
Instead of the improved air valves in the piston, with a hollow piston rod for
allowing the atmospheric air to enter to either end of the cylinder when a partial
vacuum is formed, other ordinary spring suction valves heretofore in use for the like

page_text: purpose might be fitted to the ends the cylinder, or in the ports leading thereto
when preferred.
The compressed air receivers on the car are preferably made cylindrical and of
sheet steel, copper, or other strong malleable metal plates to resist the maximum
working pressure, and of dimensions to suit the convenient spaces on or in the car,
and all connected so as to allow the compressed air to expand direct into the valve
casing (without the use of reducing valves) thus preventing loss in the expansion
of the compressed air, which is utilized wholly in the cylinder through its cut-off
valves. These receivers are charged from time to time at intermediate stations
where pumping engines and air pressure reservoirs are erected, with connecting
pipes or strong hose, all ready for re-charging the receivers of the cars as they
arrive.
These air-pumping engines might be portable, with a crank shaft of their own,
coupled by wheel gearing or otherwise to one of the shafts of the running wheels of
the car or vehicles, which in turn may or may not be coupled to the other shaft to
suit the gradients.
Instead of the arrangement of ports and valves already described for neutralizing
the cut-off valves, principally for the purpose of starting, there may be new and
additional ports in the valve face just beyond and adjacent to the admission ports,
which shall communicate with the admission ports by means of the transverse ports
in the main slide valve, in exactly the same way as the admission and exhaust ports
communicate with each other by means of the exhaust cavity in the main valve;
and the pressure fluid being admitted to these additional ports by means of a cock or
valve will find its way into the cylinders and have the desired effect.
The engines and machinery may be covered or boxed in for the purpose of keeping
out dirt and dust.
Any ordinary centrifugal pump or other governor may be used for limiting the
speed.
By another improvement the air on its way to the cylinder may be passed
through a vessel containing a solution, in water or other liquid, of gas of a high
absorptive power, such as ammonia.
Instead of the method herein-before described for admitting atmospheric pressure
to the cylinders through valves in the piston, the friction of the piston rod in a
gland may be made to open valves in the cylinder for the purpose. These of course
would not open unless the pressure in the cylinders fall below what was sufficient to
overcome the friction of the glands.
In order that the fender in front of the wheels for pushing aside obstructious may
be made to act more effectively, it may be arranged so that the driver can either
by foot, treadle, or otherwise, lower it when desired to scrape, or be nearly flush with
the street.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Hardie and John James in the Great Seal Patent Office on
the 11th October 1877.
"
ROBERT HARDIE, of Govan, in the County of Lanark, Engineer, and JOHN
JAMES, Edinburgh, in the County of Mid Lothian, Bachelor of Science and Engineer.
IMPROVEMENTS IN APPARATUS FOR OR CONNECTED WITH MOTIVE-POWER ENGINES
WORKED BY COMPRESSED AIR OR OTHER ELASTIC FLUID FOR THE PROPULSION
OF TRAMWAY CARS OR OTHER VEHICLES."
Figure 1 is a sectional plan, through one cylinder and set of valves, of a two-
cylinder air or other pressure fluid-motive engine for propelling tramway cars,
all constructed in accordance with and illustrative of one modification or arrange-
ment of the improvements of this Invention, with the cylinders 1, 2, arranged

page_text: horizontally, and bolted together by their common valvo casing 3, and secured
in any usual manner at the sides or above to the main under framing of tho
car, between the shafts W, W¹, of the two pairs of running wheels w, w¹, so as
to actuate one shaft as a crank shaft, the other shaft and its wheels being also
driven by the former through outside connecting rods connecting their wheels by
crank pins in them set at right angles on the opposite sides.
Figures 2 and 3 are longitudinal and transverse sections of the arrangement
shown in Figure 1, respoctively taken on the line 1---1 in Figure 1, and the line
2---2 in Figure 2, through the ports leading to and from the ends of the cylinder
and the exhaust port and suction and discharge valves used when the cylinders aro
acting as pumps.
Figure 4 is a sectional elovation of one arrangement of pressure liquid mechanical
brake mechanism or cylinder with double pistons and fittings, constructed in accord-
ance with and illustrative of the improvements of this Invention for working tho
brake blocks of tramway cars and other vehicles.
Our said Invention has for its object, and mainly consists in contriving, arranging,
and combining together certain new or improved apparatus or mechanism, or com-
bination of these (in or as engines) for the more efficient and economical use of
compressed air or other elastic fluid, as a means of propelling tramway cars and
other vehicles, or for railway carriages or waggons, and inany other cases where this
system of propulsion is preferable to steam, as for the motive engines or vehicles in
tunnels, mines, and ferry boats.
Under these improvements the general construction of the engine may be of the
ordinary type of high-pressure steam or compressed air expansion engines used for
propulsion purposes, with two or more cylinders, having the piston and rods acting
on their cranks and shaft, preferably at right angles, for two cylinders ranged
horizontally at an angle, or vertically, as found suitable for the particular circum-
stances or purposes to which the engines are to be applied, all adjacent to their com-
pressed air or motive working fluid vessels or receivers, which for the primary
purpose of propelling tramway cars might be made of any convenient size or length
and number, joined together by branch pipes, and disposed transversely or longitu-
dinally below the carriage or seats, or otherwise, where there is convenient space on
the car; or the traction carriage when this is used separate from the cars to draw
them.
The traction carriage or the tramway car to be used may be of any convenient
construction and form required or employed for other arrangements and modes of
propulsion, the side frames being preferably made deep enough to carry the com-
pressed air vessel in recesses through them, secured by straps and wood blocks to
prevent motion or frictional wear. When the car or vehicle to be used is carried on
two pairs of wheels w, w, and w¹, w¹, on their axles or shafts W, W³, placed as usual
at from three feet six inches to six feet or so apart, as usual under the middle of the
main lower frame, for stability and ease in turning the curves of the rails without
steering gear, it is preferred to place the cylinders or engines as 1 and 2, between
the axles W, W', securing them to and between the main side frames carrying the
springs and axle boxes, and in a line with one of the axles W as a crank shaft,
having their connecting rods directly connected to its cranks V, V, at right angles to
each other for two cylinders. The wheels w of this shaft are, when preferred, as for
gradients, directly coupled to those w² of the other shaft or axle by outside parallel-
acting connecting rods fitted on crank pins v, v, fixed in the wheels at right angles
to each other on the opposite sides. The cylinders 1 and 2 of the engine are provided
with the usual admission and exhaust ports, h, and their working pistons and
rods 1, 111, and connecting rods and guides, and with a close valve casing 3, pre-
ferably common to both, for two cylinders, and with a nearly ordinary construction
of main short-slide valve H to each, with the usual exhaust chamber in the middle
open on the face over the exhaust port or chamber D formed in the face side of each
cylinder, and having the usual transverse steam ports H, H", passing through the
valve beyond the said chamber h, and near each end of the valve H, faced on the

page_text: back and fitted with a duplex construction of expansion valve A, B, preferably of
the right and left screw cut-off kind, known as Meyer's, working on the back of the
slide valves H, all generally as so far described, without any of the special improve-
ments forming the essential subject of this Invention, and shown in Figure 1.
Referring to this Figure 1, by one of the improvements of this Invention each
half or part A, B, of the cut-off or expansion valve may be formed with a transverse
oblong port through it near the outer end, or with one in the form of a block A, and
the other B in the form of a short slide valve, with the said transverse port as C
near its outer end, and another port F leading into a longitudinal port G in the
middle of its face, having a new or additional plate-slide valve E fitted to the work
on the back of and between these two cut-off valves A and B over their ports C, F,
by a valve spindle E¹ (attached at e by snugs and screw nuts) working out through
a stuffing box E" in either end of the casing 3, and fitted with suitable hand gear
outside to work them (not shown in the Drawings), all as particularly shown in the
sectional part, Figure 1. And when the valves of both cylinders work back to back
in one casing 3, as shown in this Figure, a single central spindle E' may work both
of these new central-plate valves E with a narrow space between them and pressing
springs when desired.
The central or normal position of the new valves E, E, is neutral, but when moved
in one direction the valves shall partially or wholly cover the ports C, C, in the one
end or part, as B of the expansion valves A, B, so that the acting pressure air or
fluid in the casing 3 will not be admitted to the corresponding end of the cylinder,
and when moved in the opposite direction the valves E, E, have the effect of
rendering the expansion valves A, B, to some extent inoperative by admitting a
small quantity of the compressed air or fluid through the new passages formed in the
expansion valves A, B, direct through the main slide valve H into the cylinder, even
after the expansion valves have cut off the acting pressure fluid, and so give less or
greater power to and for starting the engines, according as these valves E, E, are
moved by a hand lever or other equivalent to any of the corresponding three
positions referred to, the inner ports F, G, of the cut-off valves being always covered
by the new valves E, E, in their normal or middle position.
By another improvement the two ports A and B of each expansion valve are
fitted with and actuated by right and left threaded screws on the two expansion
valve spindles S, S, made alternate, that is, a left-handed screw for valve A, and
right for B of cylinder 1, and right-handed screw for valve A, and left for B of
cylinder 2, as seen particularly in Figure 1, so as to actuate their valves as usual,
while the spindles S, S, are turned in opposite directions by means of right and left
worm screws 8, 81, formed or keyed on the actuating or cut-off gear shaft 8, carried
in bearings at one end of the valve casing 3, or cylinders, these worns gearing into
corresponding worm wheels 82, 83, attached or fixed on the screw valve spindles S, S,
the worm wheels gearing into each other as spur wheels, as seen particularly in the
end view, Figure 3, so that the wheels 8, 8, being moved together in opposite
directions the necessity for shoulders or collars on the worm spindle 8 is obviated,
there being no end thrust on or tendency to screw itself out of gear with the wheels
8,83, the spindles S, S, actuating the two parts A and B of each valve simul-
taneously to and from each other as turned in reverse directions, the cutting-off
edges being respectively a and b, as seen in Figure 1.
The action of the valves is as follows:-Then the valve E is moved in the direc-
tion of the arrow on its rod or stem E' until the port F in the valve B is uncovered,
the pressure fluid passes to the cylinder through the cavity G in the face of this
valve B, which is either in communication with the port H¹ direct through the
main valve H, or its port H¹¹ through the longitudinal duct k. In this way tho
engine can be started if it should happen to stop in a position when the expansion
valves had cut off, as indicated in this position in Figure 1, and when the valve E
is moved in the opposite direction until the port C is covered; then no pressure fluid
is allowed to pass from the casing 3 to the inner end of the cylinder 1 through the
ports H' and h¹; in this way the engine may thus be wrought with single or double

page_text: power. When the pressure fluid is completely cut off, as when descending a slight
gradient, it is desirable that the air passing out from the one end of the cylinder
should enter the other, as for example, let the piston 1' be travelling in the direc-
tion of the arrow at its inner end in Figure 1, air will be forced out in the direction
of the arrow through the ports 11 into the exhaust chamber D, but instead of
escaping to the atmosphere the outlet branch of the exhaust chamber, as at the
arrow D¹, Figure 2, it will be drawn or sucked through one of the suction valves d
through the port into the other or front end of the cylinder, as indicated by the
arrows at d, d, in Figures 1 and 2, and vice versa during the return stroke of the
piston, this being preferable to sucking direct from the outer atmosphere, as it
makes no noise, and takes in no dust, and when descending steep gradients it is
desirable to utilize as well as resist the force of gravity. This is done by placing
the main valve H in mid gear, so as to shut off communication with the admission
and exhaust ports h¹, h, except by the suction valve d, d, Figures 1 and 2. Air
must then be drawn in from the atmosphere at D', Figures 2 and 3, and discharged
through the discharge valves c, d, into the pressure fluid receivers by the pipe d"
leading thereto, as indicated by the arrows at c, d, thus making the cylinders
work as air force pumps when descending steep gradients. These automatic suction
inlet and discharge valves d', d", being fitted in a valve chamber d² over each other,
formed on the upper sides of the cylinders, in communication with all the ports
h, h, and exhaust chamber D, opposite or above its discharge branch D¹, all as
seen particularly in theso Figures 2 and 3.
By another arrangement these new or improved automatically acting suction
valves & may be fitted in or connected with the pistons, opening to each end of the
cylinders so as to admit atmospheric pressure to prevent the formation of a partial
vacuum in the cylinders, which would retard the working of the pistons, and other-
wise enable the cylinders to work as air-forcing pumps, as stated, in which case the
piston rods would be made tubular to admit of the passage of air from the atmo-
sphere to these valves in the piston, and new escape or pressure discharge valves,
as d, would also be fitted in connection with the admission ports h, h², leading
from the ends of the cylinder, and opening to the inside of the valve casing 3, to
relieve whatever excess of pressure may accumulate within the cylinders above that
within the casing 3 when the ordinary slide valve H is placed in mid-gear with
these usual admission and exhaust ports closed. When these delivery valves d', d²,
for both cylinders are fitted opposite each other near the ends of the valve casing;
one long spiral spring, or separate springs, on one spindle could be used to shut
them when discharging into the casing. These cylinders will in this way be
practically converted into pumps, the atmospheric air entering by the suction valves
d, d, to both ends of the cylinders, whether fitted in the pistons or in the chamber
in connection with the exhaust chamber D, and is forced through the delivery
valves, d, and chamber and pipe d" into the pressure receiver, or it might be
into the valve casing 3. Thus either of these improved arrangements of valves
enables the engines when going down steep gradients to utilize the force of gravita-
tion, and at the same time act as a brake to retard their momentum or velocity, and
so stop the car or retard its motion whenever the hand gear or link motion shuts
the slide valve H, all as herein-before described.
Instead of the improved air valves in the piston, with a hollow piston rod for
allowing the atmospheric air to enter to either end of the cylinder when a partial
vacuum is formed, other ordinary spring suction valves, heretofore in use for the like
purpose, might be fitted to the ends of the cylinder, or in connection with the ports
,, leading thereto when preferred.
By another improvement a two-way cock or valve is fitted in one of the inlet
ports (as at h*) so as to open or close the port leading to one end of the cylinder
from the slide valve, and in closing open it to the exhaust chamber and pipe D, and
thus practically, when desired, work the engines half-power by one end of each
cylinder and stroke of the piston, the levers of these new taps or valves of both

page_text: cylinders being connected so as to be actuated by one hand lever. This arrange-
inent may be used as another or alternate means to that described for making the
cylinders double or single acting.
Instead of the arrangement of ports and valves already described for neutralizing
the cut-off valves (principally for the purpose of starting) there may be new and
additional ports in the valve face just beyond and adjacent to the admission ports,
which shall cominunicate with the admission ports by means of the transverse ports
in the main slide valve in exactly the same way as the admission and exhaust
ports communicate with each other by means of the exhaust cavity in the main
valve, and the pressure fluid being admitted to these additional ports by means of a
cock or valve will find its way into the cylinders, and have the desired effect.
The engines and machinery may be covered or boxed in for the purpose of keeping
out dirt and dust.
Any ordinary or centrifugal pump or other governor may be used for limiting the
speed.
By another improvement the air on its way to the cylinder may be passed through
a vessel containing a solution, in water or other liquid, of gas of a high absorptive
power, such as aminonia.
Instead of the method herein-before described of adınitting atmospheric pressure
to the cylinders through valves in the pistons, the friction of a piston rod in a gland
may be made to open valves in the cylinder for the purpose. These, of course,
would not open unless the pressure in the cylinders falls below what was sufficient
to overcome the friction of the glands. The cylinders would be made large enough
for the maximum power required to ascend the greatest gradients on the line, the
lesser powers being regulated by the cut-off valves through their ordinary reversing
and cut-off gear, or through the new arrangement of ports and valvos herein-before
described, giving the single and double action; and the cylinders would be fitted
with pet or relief cocks and levers, with rods and handles convenient for the driver
to work them, so as to regulate or vary their pumping effect, which cocks would
also answer for lubricating the cylinders. Suitable hand gear and connections to
work all the said ordinary and new or improved valves will be fitted at either or
both ends of the car or vehicle, or in any other suitable or convenient position, and
also a pressure gauge fitted thero or at each end, with cocks and connecting
tubes, all so arranged to indicate the pressure in whatever vessel the gauge is put
in communication with.
By another improvement the compressed air may be heated between the receiver
and valve casing by passing it through a very thin copper or other pipe, coiled or
undulating through a hot water or other heater, with as great a pressure within it
as that of the air within the heating pipe, so as to heat the air quickly through the
thin pipe without the risk of bursting it, which heater may be of any convenient
construction and shape to resist the pressure within, and suit the space available,
heated by a coke or charcoal fire, or by gas or chemical flame heaters, and the water
in this heater may be made to circulate through a casing or jacketed space round
the cylinders of the engines to heat them and the air expanding within them, or
other ordinary means of heating the compressed air may be used.
The compressed air receivers on the car are preferably made cylindrical, and of
sheet steel, copper, or other strong malleable inetal plates, to resist the maximum
working pressure, and of dimensions to suit the convenient spaces on or in the car,
and all connected so as to allow the compressed air to expand direct into the valve
casing (without the use of reducing valves), thus preventing loss in the expansion of
the compressed air, which is utilized wholly in the cylinders through their cut-off
valves. These receivers are charged from time to time at terminal or intermediate
stations, where pumping engines and air pressure reservoirs are erected, with con-
necting pipes or strong hose all ready for re-charging the receivers of the cars as
they arrive. These air pumping engines might be portable, with a crank shaft of
their own, coupled by wheel gearing or otherwise to one of the shafts of the running

page_text: wheels of the car or vehicle, which in turn may or may not be coupled to the other
shaft to suit the gradients.
Referring to Figure 4, by another improvement each engine or motive car is
fitted with a liquid-acting incchanical brake consisting of a hydraulic cylinder D
actuated by oil, glycerine, or other liquid, which is not easily frozen under con-
siderable pressure, and preferably with two pistons or rams E, E¹, the oil being
admitted into the space D¹ between them, which by their rods e, e', working
out through stuffing boxes in the end covers of the cylinder D, will through the
short links e connecting the brake blocks A, A¹, either direct or through cross
heads, press these hard against the opposite wheels w, w¹; tho brake blocks, which
are jointed as usual at the top of their hanging links a to the car frame, are released
by allowing the pressure fluid to escape from the centre space D' between the pistons
E to act in the two outer or end spaces D", and so press in the pistons by equalizing
the pressure on their opposite sides after the supply is shut off; and springs & may
be fitted between the covers and pistons to ensure the release of the brake blocks
from the wheels. The air-pressure reservoir is shown at F fitted with a pipe G
and tap or valve H leading to the central space D¹ in the cylinder between the
pistons, with a pipe F¹ leading from the pump, which forces the oil into the
reservoir ; and a pipe I, I, connects the two ends of the spaces with the pipe
Gand central space D₁ through the four-way cock or valve H, the handle of which
when turned in one direction and position, as shown in Figure 4, communication is
opened between the reservoir Fand the central space D'; while at the same time com-
munication is shut between the space D¹ and the spaces D", D", when the brake is
applied; and when the handle of the cock H is moved to the other position (as indicated
by dotted lines) communication with the reservoir F and space D' is closed; while at
the same time communication is opened between the space D1 and the spaces
D", by means of the pipes I, I, when the brake is released; and as soon as the
vehicle is in motion again, the oil in the spaces D", D", is pumped back into the
reservoir F from the two pipes fand pipe f¹ leading to the pumps and pipe F¹, as
beforo stated.
In order that the fender in front of the wheels for pushing aside obstructions may
be made to act more effectively, it may be arranged so that the driver can either
by foot, treadle, or otherwise lower it when desired to scrape, or be noarly flush with
the street.
Having now described the nature of our said Invention, and the manner of
performing the same, we have to state that we not confine ourselves to tho preciso
details herein described or delineated, but what we consider novel and original, and
therefore claim as the Invention secured to us by the herein-before in part recited
Letters Patent is,-
First. The arrangement and use of the additional alterative slide valves E, E,
on the back of the expansion valves A, B, together with the new passages C, F, G,
and K, in these and the main slide valve H, for the purpose of making the cylinders
single acting and starting the engines, all substantially as herein described in
reference to and shown in Figure 1 of the accompanying Drawings, or any mere
modification thereof.
Second. The arrangement and use of right and left worms, and worm wheels
gearing into each other, as well as into the worms, for actuating the duplex ex-
pansion valves of tramway locomotives or other engines, all substantially as herein
described in reference to and shown in Figures 1 and 3 of the accompanying.
Drawings, or any mere modification thereof.
Third. The method of heating the air of tramway locomotives or other air engines
by means of passing it through a very thin pipe of good conducting material im-
mersed in a pressure bath of some hot liquid between the receiver and the engine,
substantially as herein described, or any mere modification thereof.
Fourth. The arrangement of suction and discharge valves d, d, in connection
with the ports h, h', leading to and from the ends of the cylinder of the air-
tramway locomotives or other such engines or vehicles, all substantially as and for

page_text: the purposes herein described in reference to Figures 2 and 3 of the accompanying
Drawings, or any mere modification thereof.
Fifth. The passing of the air through a solution of gas of high absorptive power,
such as ammonia, between the receivers and the heater in air-locomotive tramway
cars, or other like engines or vehicles, all substantitlly as and for the purposes
herein described, or any mere modification thereof.
Sixth. The general construction or arrangement of oil or liquid pressure-acting
mechanical brake mechanism for the actunting of the brake blocks of tramway cars
or other vehicles, substantially as herein described in reference to Figure 4 of the
accompanying Drawings, or any mere modification thereof.
Seventh. The making of the fender or guard of the wheels of tramway locomotives,
or other like engines or vehicles, so that it can be readily lowered and raised,
substantially as herein described, or any mere modification thereof.
In witness whereof, I, the said Robert Hardic, on behalf of the said John
James and myself, have hereunto set my hand and seal, this First day
of September, in the year of our Lord One thousand eight hundred and
seventy-seven.
ROBT. HARDIE. (L.S.)