IMPROVEMENTS IN THE METHOD OR MEANS OF PRO- PELLING TRAMWAY CARS AND OTHER CARRIAGES OR VEHICLES, AND IN THE APPARATUS OR MACHINERY TO BE EMPLOYED THEREIN OR CONNECTED THERE- WITH
Year: 1873

page_text: LETTERS PATENT to Thomas Wilson, of the City of London, Merchant,
for the Invention of "IMPROVEMENTS IN THE METHOD OR MEANS OF PRO-
PELLING TRAMWAY CARS AND OTHER CARRIAGES OR VEHICLES, AND IN THE
APPARATUS OR MACHINERY TO BE EMPLOYED THEREIN OR CONNECTED THERE-
WITH
"
Scaled the 18th July 1873, and dated the 21st January 1873.
PROVISIONAL SPECIFICATION left by the said Thomas Wilson at the
Office of the Commissioners of Patents, with his Petition, on the
21st January 1873.
I, THOMAS WILSON, of the City of London, Merchant, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE METHOD
OR MEANS OF PROPELLING TRAMWAY CARS AND OTHER CARRIAGES OR VEHICLES, AND
IN THE APPARATUS OR MACHINERY TO BE EMPLOYED THEREIN OR CONNECTED THERE-
WITH," to be as follows:-
My Invention relates to the construction and application of engines

page_text: by compressed air, such air having been raised to the desired pressure by
suitable machinery, and stored in suitablo reservoirs at fixed stations,
where the reservoirs carried on or otherwise attached to the cars may be
charged as required, and the engines worked for any given time according
to the capacity of the reservoirs.
The first part of the Invention relates to the cylinders, which may be
single or double acting, and two or more in number, attached in the
ordinary way to cranks on the shaft of the driving wheels; or if single
acting, the connecting rods may be attached direct to the pistons, tho
cylinders being open at the ends next the crank shaft. The cylinders:
may be worked either as ordinary expansion engines or as compound
engines; that is, the air may be let into cach cylinder at high pressure,
and be expanded as far as required in the same cylinder, or it may pass
from one cylinder to another, expanding to a certain extent in cach, the
first cylinder receiving its air from the reservoir direct, the second:
cylinder from the first, and the third (if three be used) from the second,
and so on.
The second part of the Invention consists in forming a reservoir of
small capacity as compared with the main reservoir, and in which the
air may be kept at à constant pressure, whatever pressure it may have
in the main reservoir. This is to be accomplished by means of a valvo
(regulated by a spring) opening when the pressure is below the required
amount, and closing when equal to or above it. By such means the air,
although reduced in pressure in the main reservoir from, say, 1,000 lbs. to
100 lbs. on the square inch, would always be 100 lbs. in the small reservoir,
and enable the engines to be worked at this initial pressure. As however
this involves a loss of power which it is desirable to avoid, I arrange the
several parts so that air of a variable pressure can be used in the first
cylinder, being cut off at a less or greater degree as the air in the main
⚫ reservoir is used up by means of suitable expansion gear, which can be
regulated from time to time by hand, or made self-acting. In this case
I place a small reservoir between the first and second, and sometimes
also between the second and third cylinders, from which such cylinders
are supplied, and in which the air may be expanded constantly to the
same degree. The first cylinder would thus receive its charge of air at a
variable pressure, but would discharge it always at the same pressuro,
the remaining cylinders both receiving and discharging at the several
pressures' for which arrangements had been made.
E

page_text: The next part of my Invention consists in surrounding the cylinders
and reservoirs with a chamber or chambers, which may be kept filled
with hot water or oil for the purpose of giving out to the air during
expansion the heat which had been evolved during compression. These
chambers of water or oil may be kept at a high temperature by means
of a very small furnace or chemical lamp arrangement, or may simply
be refilled at the time the reservoirs are charged at the main fixed
stations.
Another part of my Invention consists in constructing valves and
packings for engines worked by compressed air of leather saturated with
beeswax and tallow; the leather so prepared being stretched over metal
plates and used by preference in the form of "sluice" valves, which may
be actuated by screws in the ordinary way. Leather packings so prepared
may also be used for piston rods or other purposes where a perfectly tiglit
joint is required, and which it is very difficult to make and maintain with
metal alone.
The reservoirs I employ may cither be made of the best charcoal iron,
mild steel, or copper, and if of iron I prefer them galvanized inside,, so as
to avoid deterioration by rust. These reservoirs may consist of a scrics
of small cylinder, say nine inches to twelve inches in diameter, by pre-
ference of solid drawn tubes, and of any convenient length, arranged side
by side horizontally or vertically, and connected at the ends by tubes or
pipes. They would be fitted with safety valves and gauges in the same
way as steam boilers.
A further part of my Invention consists in forming a reservoir for the
final discharge of the steam from the last cylinder, in order that it may
issuc in a continuous stream instead of in puffs on cach stroke of the
engines.
And in order to aid in carrying out my Invention I propose to arrange
or have fixed stations at convenient places along the lines of tramway or
other road or way at which the air can be compressed and kept in large
reservoirs for use at any time, and from which any number of tramway

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Wilson in the Great Scal Patent Office
on the 21st July 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
WILSON, of the City of London, Merchant, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of January, in the
year of our Lord One thousand eight hundred and seventy-three, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas Wilson, Her special licence that
I, tho said Thomas Wilson, my executors, administrators, and assigns,
or such others as I, the said Thomas Wilson, my executors, adminis-
trators, and assigns, should at any time agree with, and no othors, 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 THE METHOD OR
MEANS OF PROPELLING TRAMWAY CARS AND OTHER CARRIAGES OR VEHICLES, AND IN
THE APPARATUS OR MACHINERY TO BE EMPLOYED THEREIN OR CONNECTED THERE-
WITH," upon the condition (amongst others) that I, the said Thomas
Wilson, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and scals, should particularly
describe and ascertain tho nature of the said Invention, and in what
manner the same was to be performed, and cause the same to bo filed
in the Great Scal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Wilson, do hereby declaro
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement in writing, and on reference being had to the
accompanying Drawings, that is to say:-
My Invention relates to the construction and application of engines
for propelling tramway cars and other carriages or vehicles to be worked
by compressed air, such air having been raised to the desired pressure
by suitable machinery, and stored in suitable reservoirs at fixed stations,
where the main reservoirs carried on or otherwise attached to the cars

page_text: may be charged as required, and the engines worked for any given time
according to the capacity of the main reservoirs.
The first part of the Invention relates to the cylinders, which may bc
single or double acting, and two or more in number, attached in the
ordinary way to cranks on the shaft of the driving wheels; or if single
acting the connecting rods may be attached direct to the pistons, the
cylinders being open at the ends next the crank shaft. The cylinders
may be worked cither as ordinary expansion engines or as compound
engines; that is, the air may be let into cach cylinder at high pressure,
and be expanded as far as required in the same cylinder, or it may pass
from one cylinder to another, expanding to a certain extent in cach, the
first cylinder receiving its air from the reservoir direct, the second
cylinder from the first, and the third if three be used from the second,
and so on.
The second part of the Invention consists in forming a reservoir of
small capacity as compared with the main reservoir, and in which the
air may be kept at a constant pressure, whatever pressure it may have
in the main reservoir. This is accomplished by means of a valve (regu-
lated by a spring) opening when the pressure is below the required
amount, and closing when equal to or above it. By such means the air,
although reduced in pressure in the main reservoir from, say, 1,000 lbs.
to 100 lbs. on the square inch, would always be say 100 lbs. in the
small reservoir, and enable the engines to be worked at this initial
pressure. As however this involves a loss of power, which it is desirable
to avoid, I arrange the several ports so that air of a variable pressuro
can bo used in the first cylinder, being cut off at a less or greater
degree as the air in the main reservoir is used up by means of suitable
expansion gear, which can be regulated from time to time by hand, or
made self-acting. In this case I place a small reservoir between the
first and second, and sometimes also between the second and third
cylinders, from which such cylinders are supplied, and in which the air
may be expanded constantly to the same degree. The first cylinder
would thus receive its charge of air at a variable pressure, but would
discharge it always at the same pressure, the remaining cylinders both
receiving and discharging at the several pressures for which arrange-
ments had been made.
The next part of my Invention consists in surrounding the cylinders
and reservoirs with a chamber or chambers, which may be kent filled

page_text: with hot water or oil for the purpose of giving out to the air during
expansion the heat which had been evolved during compression. These
chambers of water or oil may be kept at a high temperature by means
of a very small furnace or chemical lamp arrangement, or may simply
be refilled at the time the reservoirs are charged at the main fixed
stations.
Another part of my Invention consists in constructing valves and
packings for engines worked by compressed air of leather saturated with
beeswax and tallow; the leather so prepared being stretched over metal
plates and used by preference in the form of "sluice" valves, which may
be actuated by screws in the ordinary way. Leather packings so prepared
may also be used for piston rods or other purposes where a perfectly tight
joint is required, and which it is very difficult to make and maintain with
metal alone.
The reservoirs I employ may either be made of the best charcoal iron,
mild steel, or copper, and if of iron I prefer them galvanized inside, so as
to avoid deterioration by rust. These reservoirs may consist of a series
of small cylinders, say nine to twelve inches in diameter, by preference
of solid drawn tubes, and of any convenient length, arranged side by side
horizontally or vertically, and connected at the ends by tubes or pipes.
They would be fitted with safety valves and gauged in the same way as
steam boilers.
A further part of my Invention consists in forming a reservoir for the
final discharge of the steam from the last cylinder, in order that it may
issuc in a continuous stream instead of in puffs on each stroke of the
engines.
And in order to aid in carrying out my Invention I propose to arrange
or have fixed stations at convenient places along the lines of tramway or
other road or way at which the air can be compressed and kept in large
reservoirs for use at any time, and from which any number of tramway
carriages or engines for moving the same or other vehicles can be charged
as required.
In order that my Invention may be better understood, reference
should be made to the annexed Sheet of Drawings and accompanying
description.
Figures 1, 2, and 3 shew sectional clevation, cross section, and
sectional plan respectively of a tramway car, the letters of reference

page_text: being the same in each view. A, A, A, shew the main reservoir, con-
sisting of cylinders or tubes by preference of from six to twelve inches in
diameter and four to six feet in length, arranged in either or all of the
ways shown, viz., vertically at the centre part of the car at each side, or
horizontally along the floor under the seats or under the body of the car
either in one or more tiers, according to size of tubes and the distance
desired to travel, and the pressure of air with which they are first charged.
The reservoir tubes may also be placed under the seat or the roof if
desired, their particular disposition being immaterial. These tubes aro
all connected together at their ends or elsewhere by small tubes screwed
or otherwise attached to the caps at the ends of the larger tubos, as
shown at Figures 4 and 5, Figure 4 shewing the cap B screwed on, and
Figure 5 the cap B secured to the tube by means of a central bolt or
small tube, which acts as a stay, as shown. The cap B in Figure 5 has a
groove cut in it at C, in which a ring of leather or vulcanized rubber
may be placed to make the joint. The small holes at D, D, in the small
stay tube are for effecting the necessary communication. In Figures 1,
2, and 3, E, E, shew the cylinders shown in the Drawing, two in number,
and arranged at compound engines, one being larger than the other and
supplied from it. In the Drawing also is shewn the simplest arrange-
ment of outside cranks on one pair of wheels, although more than two
cylinders can be employed and double crank axles can be used, and the
cylinders placed closer together. The cylinders shown are fitted with
ordinary guide bars, guides, and connecting rods, but trunk cylinders can
be used, in which caso the guide bars would be dispensed with. Arrange-
ments could also be made for driving both pairs of wheels if necessary
by side rods or a duplication of the cylinders, the expansion being carried
out in all four cylinders if desired, one after the other.
The tubes marked F, F, in the neighbourhood of the cylinders and
wheels, which are shewn shorter than the others, either one or more in
number, could be conveniently used as the intermediate reservoir, in
which the air may be maintained at a uniform pressure before passing to
the small or first cylinder. The arrangement by which this uniform
pressure is maintained is shewn in Figure 6, in which the arrow indicates
the direction in which the air from main reservoir enters. The plunger G
is accurately fitted to the chamber K, and is acted upon by a spring L,
which keeps it down so long as the pressure in F is below that required,
the openings I and J in plunger and chamber -respectively being in

page_text: communication. When the pressure in F rises to the extent required,
and which the spring cannot balance, the plunger rises and the commu-
nication is stopped until the pressure in F again falls, and the openings
are again placed in communication. Instead of a solid plunger one may
be employed with leather packings.
The backward and forward motion of the car is determined by means
of the ordinary link motion attached to the cylinder valves, the links
being moved by an ordinary lever or screw at the side of the car and at
the ends of the journeys; or, if needed, of course rods can be carried to
both ends of the car, so as to enable the driver to reverse the motion
without leaving his place. Such communication must of course be made
between the stop or regulating valve and the driver, at whichever end he
may be.
The construction of the stop or regulating valve is shown in Figures 7
and 8, and consists of an ordinary sluice valve fitted, as shewn, with a
disc of leather steeped in beeswax and tallow, the exposed surface of the
leather bearing against the inclined face of the valve seat. The valve is
guided vertically by facing strips at the back and front M, M, and is
actuated by an ordinary screw arrangement either in the gland or in a
thimble carried by a bridge piece, an arrangement well understood.
Figure 0 shows a simple mode of forming a piston with leather (by
preference prepared with beeswax and tallow) packings N, N, suitable in
some cases for working in an air cylinder, its tightness being secured by
the pressure of the air itself on the outside surfaces of the leather
packings.
In the event of using no intermediate reservoir F, the first cylinder
into which the air from the main reservoir would act would be fitted
with an ordinary variable expansion valve, capable of being altered from
time to time while the cylinder was in motion. As there are many
valves of this kind used in steam engines it is unnecessary here to
describe the arrangement further, except that it is of course intended to
work it from either end of the car by suitable rods and levers.
ม
Between the large and small cylinders, if the cranks are placed at
right angles, a small reservoir or chamber must be placed, and one of
the short tubes marked F, in Figure 3, can be employed for this purpose
if made of suitable size, or a mere pipe connection will answer the
purpose if the cylinder be small.

page_text: In any of the positions shewn for the main reservoir tubes, they may
bc enclosed in thin iron cases, which can be filled with hot water or oil,
and may be so connected as that the hot water could be kept in circu-
lation by means of a small chemical lamp furnace, which could be placed
in any convenient position, such as under the vertical set of tubes, at
cither side of the car, in its centre, and to which access would be given
from the outside alone.
When no intermediate reservoir is used it will be more convenient to
employ three cylinders, the central one being the smallest, and taking
the air direct from the reservoir, the others being supplied, No. 2 from
No. 1, and No. 3 from No. 2, chambers being placed between each pair
respectively. In this case the central crank and the two outside cranks
would be coupled at 120°.
The main reservoir would be charged by an ordinary screw coupling,
the pipes from the fixed stations, a reservoir being carried to thic starting
points; or in certain cases the cars could be taken at the end of cach
journey to the fixed station, or a travelling reservoir could ply between
the fixed stations and the starting points, and so supply the power as
required. The hot water for charging the reservoir tube chambers could
be supplied from the fixed stations without additional expense, as con-
siderable heat is evolved in the compression of the air, the pumps for
which should be kept surrounded with flowing water. The heat so
evolved should be given back to the air during its expansion, which
would prevent all inconvenience from freezing, thickening of oil used in
lubrication, &c.
Having now described the nature and object of my said Invention for
"Improvements in the Method or Mcans of Propelling Tramway Cars
and other Carriages or Vehicles, and in the Apparatus or Machinery to
be employed therein or connected therewith," together with the manner
in which the same is to be or may be performed or carried into practical
effect, I would remark in conclusion that I claim as my Invention,-
Firstly. The construction of machinery for propelling ordinary tram-
way cars by compressed air, and its application thereto, substantially as
described.
Secondly. The mode of working compressed air through the first of a
scries of two or more cylinders direct from the main reservoir by means
of ordinary variable expansion gear.

page_text: Thirdly. The construction of an intermediate reservoir, substantially as
described, in which the compressed air is maintained at a uniform
pressure, and upon which the first cylinder is supplied.
Fourthly. The application and use in compressed air engines of small
reservoirs between the pair or pairs of cylinders for the purpose of 5
enabling any number to be attached to the same crank shaft, with
cranks of various angles from cach other.
Fifthly. The envelopment of the several cylinders or tubes composing
the main reservoir or the small intermediate reservoirs in tanks or cases
containing hot water or oil for the purpose of returning to the expanding 1
air the heat climinated during its compression.
Sixthly. The application and use of a small chemical lamp furnace
to any convenient part of the said system of reservoir tubes for the
purpose of keeping the fluid at which they are placed at the requisite
temperature.
"
Seventhly. The modes, substantially as described, of closing the ends
of the reservoir tubes either by caps screwed on or by caps secured by
through" bolts or stay tubes.
1
Eighthly. The construction and application of valves and packings of
leather saturated with beeswax and fallow, substantially as described, for 2
retaining air when highly compressed.
Ninthly. The construction and application of a portable reservoir to be
used in the transport of the power from the proposed fixed stations to
the points of starting and stopping of the tramway cars.
In witness whereof, I, the said Thomas Wilson, have hereunto set 2
my hand and seal, this Nineteenth day of July, in the year of our
Lord One thousand eight hundred and seventy-three.