IMPROVEMENTS IN MACHINERY OR
Year: 1880

page_text: LETTERS PATENT to Edmund Edwards, of the Firm of Edwards and Co.,
Engineers and Patent Agents, of 40, Southampton Buildings, in the County
of Middlesex, for an Invention of "IMPROVEMENTS IN MACHINERY OR
PROVISIONAL SPECIFICATION left by the said Edmund Edwards at the
Office of the Commissioners of Patents on the 31st August 1880.
EDMUND EDWARDS, of the Firm of Edwards and Co., Engineers and Patent
Agents, of 40, Southampton Buildings, in the County of Middlesex. "IMPROVE-
MENTS IN MACHINERY OR APPARATUS FOR PROPELLING CARRIAGES UPON
TRAMWAYS OR OTHER ROADS."
My Invention relates to machinery or apparatus used for propelling carriages
upon tramways or other roads by means of compressed air, steam, or other
sufficiently elastic gas or vapour, and more especially to that form of such apparatus
in which cylinders are used containing moveable pistons of great length of stroke
in proportion to their diameter, operating by means of toothed racks or their
equivalents upon corresponding toothed pinions or their equivalents which actuate
the driving wheel or wheels of the car, so that the driving wheel makes one or
more complete revolutions during each single stroke of the pistons.
My Invention has for its objects more especially improved methods of constructing
and arranging the cylinders and pistons with the toothed racks and pinions which
communicate motion to the driving wheel, and also of new and improved methods
of arranging and actuating the valves by which the compressed air or other elastic
driving fluid is admitted and properly distributed to and from the cylinders.
In order to carry out my Invention I take a tramcar preferably supported upon
four flanged wheels, and having a fifth central driving wheel of larger diameter
operating upon the road between the rails which support the car.
The framework of the tramcar is supported by the flanged wheels revolving in
axle boxes, and I prefer to provide the central driving wheel described with a
strong india rubber tyre, the said wheel being fitted upon an axle carried in
bearings of the usual description.

page_text: The rack
The cylinders for the compressed air or other driving fluid are arranged opposite
to each other in the same line (in plan), and are provided with pistons and rods,
the ends of the latter being connected to corresponding projecting brackets, one of
which is attached to each extremity of the rack frame, which can move longitudinally
backward and forward upon guides attached to the frame of the car.
frame is provided with an upper and lower toothed rack gearing into two toothed
wheels, and these two toothed wheels revolve freely upon the axle of the driving
wheel, but are provided with pawls gearing with ratchet wheels which are fixed
upon the driving axle, so that when turned in one direction the wheels cause the
axle to revolve with them, but in the other direction they can revolve without the
said driving axle.
When therefore the pistons are made to reciprocate backward and forward in
the cylinders the rack frame moves with them, and causes the driving axle and
wheel to revolve continuously in the same direction.
By the improved arrangement, as above described, the cylinders, and the length
of stroke backward and forward of the pistons and rack frame, is made as great
as possible in proportion to the length of the tramcar.
Reservoirs for containing the compressed air or other material are placed in
convenient positions upon the tramcar.
In order to actuate the pistons backward and forward I arrange two three way
cocks or valves fixed to the outer ends of the cylinders so that their plugs are in
line with each other, and these plugs are connected to spindles, the inner ends of
which are supported in a central bearing so that either plug can be turned as
required by means of its spindle. Upon each plug or its spindle is fixed a catch
actuated by suitable springs or weights, so that when the catch is released the
plug is turned by the spring so far that the inlet opening from a pipe connected
with the reservoirs communicates with the cylinder, whilst if the catch be turned
partly round the communication is cut off from the reservoirs, and the piston
continues its stroke by the expansion of the compressed air or other material, and
if the catch be turned still further a communication is made between the cylinder
and a discharge pipe. A detent is arranged turning upon a centre and retaining
the catch in either position.
Upon the valve spindle I arrange an arm or lever which can be fixed at any
part of the length of the spindle, and upon the rack frame I fix a cam or inclined
plane, so that as the rack frame travels forward by the action of the piston the
cam strikes the arm and shuts off the compressed air from the cylinder. The
piston and rack frame continue their course to the end of their stroke, when the
cam strikes a second arm upon the spindle and so opens a passage to the exhaust
pipe, the valve spindle being retained in its several positions by the detent.
The rack frame then commences its return stroke by the action of the opposite
cylinder and piston, and upon their reaching the inner end of the stroke a second
small cam upon the rack frame releases the detent described, and the action of the
spring or weight upon the catch already described turns the valve spindle and
opens a passage for the re-admission of compressed air.
Precisely similar apparatus is employed to actuate the valve of the second
cylinder.
The arrangement of apparatus described is necessary instead of using a cam to
open the valve for the admission of compressed air, for in the latter case as soon
as the valve became opened sufficiently to admit a small quantity of air the
further action of the cam would cease.
In order to provide for the gradually decreasing pressure of air in the reservoirs
during a journey of the tramcar, I prefer to alter gradually the position of the
arms upon the valve spindles, so that as the pressure decreases, the admission of
compressed air may be cut off less early during the stroke.
For this purpose I make the arms so that they can slide along the valve
spindles, but without being able to turn round upon the latter. And I connect the
said arms by means of toothed racks and pinions, or levers and rods, to a handle

page_text: within the control of an attendant, so that he can at any time whilst the car is
travelling alter and adjust the position of the two arms, so that they are simul-
taneously brought nearer to or further from the outer ends of their respective valve
spindles as may be desired.
Instead of the revolving plugs to the valves as described, slide valves actuated
by the valve spindles in a similar way and for the same purpose may be used.
The valves are connected to the reservoirs by suitable pipes provided with
regulating valves, and the reservoirs may be arranged either so that they can
readily be recharged with compressed air' when necessary, or so that others can be
substituted for them.
Instead of the driving wheel being fixed upon the axle which carries the toothed
wheel, it may be fixed upon a separate axle which is driven by the driving axle
with the intervention of a flexible coupling, so that more perfect action of the
bearing springs of the tramcar is thus possible.
Another method which may be used for actuating the valves as above described
is the following:-I arrange the spindles of the two parallel, but not in the same
line with one another, and I arrange their inner ends so that each can be fitted
with a quadrant shaped catch, the two quadrants being arranged opposite to one
another and their edges fitting into one another, in such manner that when one of
them has been turned round sufficiently far to close the exhaust port of the
cylinder with which it is connected, it releases the other, the spring or weight upon
which turns it round and opens its admission port.
When the latter has in its turn been made to revolve by the action of the cam
upon the rack frame sufficiently far to open its exhaust port it releases the first
quadrant, the spring or weight upon which turns it and opens its admission port,
and so on, continuously as long as may be desired.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edmund Edwards in the Great Seal Patent Office on the 28th
February 1881.
EDMUND EDWARDS, of the Firm of Edwards and Co., Engineers and Patent
Agents, of 40, Southampton Buildings, in the County of Middlesex. "IMPROVE.
MENTS IN MACHINERY OR APPARATUS FOR PROPELLING CARRIAGES UPON
TRAMWAYS OR OTHER ROADS."
My Invention relates to machinery or apparatus used for propelling carriages
upon tramways, railways, or other roads, by means of compressed air, steam, or
other sufficiently elastic gas or vapour, and it relates more especially to that form of
such apparatus in which cylinders are used containing moveable pistons having a
stroke of great length in proportion to their diameter, operating by means of
toothed racks or their equivalents upon corresponding toothed pinions or their
equivalents, which actuate the driving wheel or wheels of the car, so that the

page_text: driving wheel makes preferably one or more complete revolutions during each
single stroke of the pistons.
My Invention has for its objects more especially improved methods of con-
structing and arranging the cylinders and pistons with the toothed racks and
pinions which communicate motion to the driving wheel, and also of new and
improved methods of arranging and actuating the valves by which the compressed air
or other elastic driving fluid is admitted and properly distributed to and from the
cylinders in which it drives the pistons. In order to carry out my Invention, and
supposing it to be applied to an ordinary tramcar, I take such a car preferably
supported upon four flanged wheels, and having a fifth central driving wheel of
larger diameter operating upon the road between the rails which support the car,
or upon a separate independent rail laid to support it. The frame work of the
tramcar is supported by the flanged wheels revolving in the usual way in axle
boxes, and I prefer to provide the central driving wheel described with a strong
india rubber tyre, the said wheel being fitted upon an axle carried in bearings of
the usual description.
The single acting cylinders in which the compressed air or other driving fluid
operates are arranged opposite to each other in the same line (in plan), and are
provided with pistons and rods, the ends of the latter being connected to
corresponding projecting brackets, one of which is formed upon or attached to
each extremity of a rack frame which can move longitudinally backward and
forward upon cylindrical or other guides attached to the frame of the car.
The rack frame is provided with an upper and lower toothed rack, each gearing
into one of two toothed wheels, and these two toothed wheels revolve freely side
by side upon the axle of the driving wheel, but are provided with palls gearing
with ratchet wheels which are fixed upon the driving axle, so that when turned in
one direction the wheels cause the axle to revolve with them, but in the other
direction they can revolve without affecting the said driving axle.
When therefore the pistons are made to reciprocate backward and forward in
the cylinders, the rack frame moves with them and causes the driving axle and
wheel to revolve continuously in the same direction.
In the accompanying Drawings, which are in illustration of my Invention, the
improved arrangements of parts are shown applied to a tramcar supported upon
four Banged wheels, and having a fifth central driving wheel of larger diameter
operating upon the road between the rails which support the car. It is to be
understood that the Drawings show only the method in which my Invention is to
be applied, and do not represent in exact detail or proportion the parts of an
ordinary tramcar or of the apparatus. Figure 1 is a plan showing a tramcar with
the upper part removed; Figure 2 is a transverse section of the same, and Figure 3
a side view; Figure 3º is a longitudinal section on a larger scale of one method of
arrangement of the cylinders and valves, and the apparatus by which the valves
are actuated; Figures 4, 5, 6, and 7 are transverse sections showing the valve and
the method of actuating it; and Figures 8 and 9 shew on a larger scale the toothed
wheels and ratchet wheels by which the driving wheel is itself driven.
Figure 10 is a side view of the driving wheel. The same letters of reference
indicate the same parts in the several Figures. a is the wooden framework of the
tramcar, supported by the flanged wheels b, b, which revolve in the axle boxes c, c.
The centre driving wheel d is shewn provided with a strong india rubber tyre, as
shewn at vin Figure 10, and is fitted upon an axle e carried in bearings f, f. The
cylinders g, g¹, are arranged in the same line (in plan), but that marked g is at a
higer level than g¹. They are provided with pistons h, h', and rods i, i, the ends
of the latter being connected to corresponding projecting brackets k, k', one of
which is at each extremity of the rack frame 1, which can move longitudinally
backward and forward upon guides m, m', attached to the frame of the car.
rackframe is provided with an upper toothed rack n gearing into the toothed
wheel 0, and a lower toothed rack n' gearing into the toothed wheel o' and these
two wheels o, o¹, revolve freely upon the axle e of the driving wheel d, but are
The

page_text: provided with palls p, p, gearing with rachet wheels r, ¹, which are fixed upon
the axle e, so that when turned in one direction the wheels o, o¹, cause the axle e to
revolve with them, but in the other direction they can revolve without the axle 6.
If therefore the pistons are made to reciprocate backward and forward in the
cylinders, the rack frame moves with them, and causes the axle e and driving
wheel d to revolve continuously in the same direction.
By the arrangement described it will be seen that the cylinders and the length
of stroke backward and forward of the pistons and rack frame are made very great
in proportion to the length of the tramcar. In Figure 2 A and A' represent
reservoirs for compressed air, whilst a third reservoir A is shewn at the top of
the car.
In Figures 3, 4, 5, 6, and 7, the cylinders g, g³, are shewn in section, g¹ being
shewn broken off; 8, 81, are three way cocks or valves fixed to the outer ends of
the cylinders so that their plugs are in line with each other, and these plugs are
connected to the spindles t, t¹, the inner ends of which are supported in a central
bearing at v, so that either plug can be turned as required by means of its spindle.
Upon each plug or its spindle is fixed a catch w, w₁, actuated by suitable springs
(not shewn in the Drawings), so that when the catch is released the plug is turned
by the spring so that the inlet opening from a pipe connected with the reservoirs
communicates with the cylinder, as shewn in Figure 5, whilst if the catch be
turned partly round, as shewn in Figure 6, the communication is cut off from the
reservoirs, and the piston continues its stroke by the expansion of the compressed
air, and if the catch be turned still further a communication is made between the
cylinder and an exhaust pipe, as shewn in Figures 4 and 7.
A detent x turning upon the centre y retains the catch win either position.
Upon the valve spindle t arrange an arm or lever B which can be fixed at any
part of the length of the spindle, and upon the rack frame I fix the cam or
inclined frame C, so that as the rack frame travels forward by the action of the
piston the cam strikes the arm B and shuts off the compressed air from the
cylinder. The piston and rack frame continue their course to the end of their
stroke, when the cam c strikes the second arm D upon the spindle t, and so opens
a passage to the exhaust pipe. The rack frame then commences its return stroke
by the action of the opposite cylinder and piston, and upon their reaching the inner
end of the stroke a second small cam upon the rack frame (shewn at E, in Figure 6)
instantly releases the detent x, and the action of the spring already described upon
the catch turns the valve and opens a passage for the re-admission of compressed
air. Precisely similar apparatus is employed to actuate the valve of the second
cylinder g. The arrangement of apparatus described is necessary instead of
using a cam to open the valve for the admission of the compressed air; for in the
latter case as soon as the valve opened sufficiently to admit a small quantity of
air the further action of the cam would cease. Another method which may be
used for actuating the valves as above described is the following:-I arrange the
spindles of the two valves parallel, but not in the same line with one another, and
I arrange their inner ends so that each can be fitted with a quadrant-shaped catch,
the two quadrants being arranged opposite to one another, and their edges fitting
into one another in such manner that when one of them has been turned round
sufficiently far to close the exhaust port of the cylinder with which it is connected
it releases the other, the spring or weight upon which turns it round and opens its
admission port. When the latter has in its turn been made to revolve by the
action of the cam upon the rack frame sufficiently far to open its exhaust port it
releases the first quadrant, the spring or weight upon which turns it and opens its
admission port, and so on continuously as long as may be desired. This method of
arrangement is illustrated in Figure 14, in which t, t, are the two valve spindles,
the inner ends of which are fitted with the quadrants y, y', which are actuated in
turn as described by springs or weights 3, 1. In order to provide for the gradually
decreasing pressure of air in the reservoirs during a journey it is advisable to alter
gradually the position of the arms B, B¹, upon the valve spindles, so that as the

page_text: pressure decreases the admission of compressed air may be cut off less early during
the stroke. For this purpose I make the arms B, B', so that they can slide along
the valve spindles, but without being able to turn round upon the latter, as shewn
in Figures 11 and 12, in which F, F, are keys upon which the arms B, B¹, slide
upon the valve spindles t, t'. A right and left handed screw G under the control
of an attendant carries the nuts I, I', which embrace the centres of the arms B, B',
so that at any time whilst the car is travelling the attendant can by turning the
screws G alter and adjust the position of the two arms, so that they are simulta-
neously brought nearer to or further from the outer ends of their respective valve
spindles, as may be desired. For the same purpose toothed racks and pinions or
levers and rods may be used to alter the position of the arms B, B¹. Instead of
revolving plugs to the valves, as described, flat or curved slide valves actuated by
the valve spindles in a similar way and for the same purpose may be used, as
illustrated in Figure 13, in which is the cylinder and s a valve case containing
the valve w actuated by the valve spindle t. The valves are connected to the
reservoirs by suitable pipes provided with regulating valves; and the reservoirs
may be arranged either so that they can readily be re-charged with compressed
air when necessary, or so that others can be substituted for them. Instead of the
driving wheel being fixed upon the axle which carries the toothed wheels it may
be fixed upon a separate axle, which is driven by the driving axle with the inter-
vention of a flexible bearing or coupling, so that more perfect action of the springs
of the tramcar is thus attained.
Having now described my Invention, and the manner in which it is to be
performed, I claim:-First, in apparatus in which direct-acting cylinders of great
length of stroke are used for propelling carriages having or other driving wheels
actuated by means of compressed air, steam, or other clastic gas or vapour,
the double rack frame, toothed pinions, ratchet wheels, and palls connected to and
in combination with the pistons and single-acting cylinders, substantially in the
manner and for the purpose described and shewn; also, the methods of actuating
the pistons in such cylinders by means of the plug or slide valves, valve spindles,
lovers or bars, catches and detents, quadrants, and cams, substantially in the
manner described and shewn in the Drawings; also, the methods of varying the
amount of expansion of the compressed air, steam, or other elastic gas or vapour,
in such cylinders, by means of the adjustable levers or bars sliding upon the valve
spindles, in combination with the right and left handed screws or racks and
pinions, or levers and rods, substantially in the manner described and shewo.
Also, the general arrangement of the machinery or apparatus, substantially as
and for the purposes described and shewn.
In witness whereof, I, the said Edmund Edwards, have hereunto set my
hand and seal, this 28th day of February, in the year of our Lord 1881.