IMPROVE- MENTS IN LOCOMOTIVE CARRIAGES FOR TRAMWAYS OR COMMON ROADS
Year: 1877

page_text: LETTERS PATENT to William Dundas Scott-Moncrieff, of Glasgow, in the
County of Lanark, North Britain, Engineer, for the Invention of "IMPROVE-
MENTS IN LOCOMOTIVE CARRIAGES FOR TRAMWAYS OR COMMON ROADS."
Cooled the 0th Contember 1877 and dated the 28th March 1877.
PROVISIONAL SPECIFICATION left by the said William Dundas Scott-
Moncrieff at the Office of the Commissioners of Patents on the 28th March
1877.
WILLIAM DUNDAS SCOTT-MONCRIEFF, of Glasgow, in the County of Lanark,
North Britain, Engineer. "IMPROVEMENTS IN LOCOMOTIVE CARRIAGES FOR TRAM-
WAYS OR COMMON ROADS."
This Invention relates to locomotive carriages for tramways or common roads,
and of the kind described in the Specifications of Patents granted to the present
applicant, and dated one, 10 March 1874 (No. 868), and another, 27 April 1874
(No. 1458), and comprises various improvements.
One improvement relates to the mode of working the locomotive carriage by
means of compressed air, wherein automatically adjustable cut-off valves are used
for regulating the extent of the supply of compressed air at each stroke in inverse
accordance with the gradually diminishing pressure. It is an object of any such
regulating arrangement to obtain a suitable average pressure throughout the stroke
(or throughout the effective part of the stroke), and when the carriage proceeds at
a uniform speed, and with a uniform resistance for some distance, the same average
pressure should be applied for a time, during which the pressure in the receiver and
the consequent action of the cut-off valves may vary considerably. In other words
it is desirable that the total work done by the air at each stroke should remain the
same during the continuance of uniform external conditions. The result indicated is
unattainable with the simple variable cut-off arrangement, because with the higher
pressures and shorter admissions, the quantities of compressed air sufficient for

page_text: yielding the desired amount of work would be expanded below atmospheric pressure
before the end of the stroke would be reached, and the completion of the stroke
would be effected at a loss of speed or of compressed air, if more air were admitted
to prevent loss of speed.
By the present Invention the difficulty is overcome by practically increasing the
effective stroke in inverse accordance with the diminishing air pressure, and the
simplest means for accomplishing this is by fitting in connection with the cylinders
valves, arranged so that air may freely enter from outside whenever the pressure.in
the cylinders gets below atmospheric pressure, and thus act as an automatic negative
exhaust. This improvement may also be advantageously applied even when the
admission is regulated by hand.
By another modification the cut-off valve details are arranged to always admit
as much compressed air as will expand down to atmospheric pressuro, but not lower
on approaching the completion of the stroke, and change wheel or variable frictional
gearing is introduced between a first motion shaft and the driving axle, so that a
variable piston speed may be used with a uniform speed of the driving axle.
By another improvement a variable cut-off arrangement, such as that described
in my earliest Specification herein-before referred to, is adjusted by means of any
suitable known kind of speed governor deriving its motion from the engine, instead
of being adjusted by a piston acted on by the coinpressed air in the receiver.
In carrying out the present Invention it is preferred to adopt the general arrange-
ment of air receiver described in the second earlier Specification herein-before
referred to, excepting in the construction of the separate air vessels, which are to
consist of entirely welded cylinders with curved ends, patches being welded or
rivetted on the ends by which the vessels are attached to the framing.
The present Invention also comprises a minor improvement relating to the handing
details which consist in working all the various rods or levers that have to bo
moved by hand by means of a set of vertical spindles arranged in one pedestal at
the end of the carriage, such spindles being connected by bevil wheels or other-
wise to hand wheels arranged conveniently at the top of the pedestal.. If thero
are sets of handing details at each ond of the carriage, the hand wheels at one end
may be covered by a hood or casing when the driver is at the other end.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Dundas Scott-Moncrieff in the Great Seal Patent Office on
the 27th September 1877.
WILLIAM DUNDAS SCOTT-MONCRIEFF, of Glasgow, in the County of Lanark,
North Britain, Engineer. "IMPROVEMENTS IN LOCOMOTIVE CARRIAGES FOR TRAM-
WAYS OR COMMON ROADS."
My said Invention relates to locomotive carriages for tramways or common roads,
and of the kind described in the Specifications of Patents granted to me and
dated, one, 10 March 1874 (No. 868), and another, 27 April 1874 (No. 1458),
and comprises various improvements.
And in order that my said Invention, and the manner of performing the same
may be properly understood, I hereunto append a Sheet of explanatory Drawings
to be herein-after referred to, and representing some of my improved details or
arrangements. In these Drawings the saine reference numerals are used to mark the
same or like parts wherever they are repeated.
One of my improvements relates to the mode of working the locomotive carriage
by means of compressed air, wherein automatically adjustable cut-off valves are used
for regulating the extent of the supply of compressed air at each stroke in inverse

page_text: accordance with the gradually diminishing pressure. It is an object of any such
regulating arrangement to obtain a suitable average pressure throughout the stroko
(or throughout the effective part of the stroke), and when the carriage proceeds at
a uniform speed and with a uniform resistance for some distance, the same average
pressure has to be applied for a time, during which the pressure in the receiver and
the consequent action of the cut-off valves may vary considerably. In other words
it is desirable that the total work done by the air at each stroke should remain the
same during the continuance of uniform oxternal conditions. The result indicated
is unattainable with the simple variable cut-off arrangement, because with the
higher pressures and corresponding shorter admissions, the quantities of compressed
air sufficient for yielding the desired amount of work would be expanded below
atmospheric pressure before the end of the stroke would be reached, and the
completion of the stroke would be effected at a loss of speed or of compressed air if
more air were admitted to prevent loss of speed.
By my present Invention the difficulty is overcome by practically increasing the
effective stroke in inverse accordance with the diminishing air pressure, and the
simplest means for accomplishing this is by fitting in connection with the cylinders
valves, arranged so that air may freely ontor from outside whenever the pressure in
the cylinders gets below atmospheric pressure, and thus act as an automatic negative
exhaust.
Figure 1 on the accompanying Sheet of Drawings is a transverse vertical section
of one of the cylinders of my compressed air locomotive carriage, showing tho
manner in which I prefer to apply the valve referred to. It is a simple conical
cheek valve 1, set in a small box 2, to which the external air has access by lateral
holes, and it opens into a passage 3, communicating with the top of the cylinder 4
at about the middle of its length, or two such valves may be applied one at each
end of the cylinder. This improvement may also be advantageously applied when
the admission is regulated by hand.
By another modification the cut-off details are arranged to always admit as much
compressed air as will expand down to atmospheric pressure but not lower, on
approaching the completion of the stroke and change wheel, or variable frictional
gearing is introduced between a first motion shaft and the driving axle, so that
a variable piston speed may be used with a uniform speed of the driving axle.
By another improvement a variable cut-off arrangement, such as that described
in any earliest Specification herein-before referred to, is adjusted by any suitable
known kind of speed governor deriving its motion from the engine, instead of being
adjusted by a piston acted on by the compressed air in the receiver. The kind of
governor which I consider best adapted for my purpose is one in which the positive
action of a pump forces a liquid into a cylinder provided with a piston connected
to the valve adjusting details, and from which cylinder the liquid escapes through
a passage the effective area of which is determined by an adjustable valve.
In carrying out my present Invention I prefer to adopt the general arrangement
of air receiver described in my second earlier Specification herein-before referred to,
excepting in the construction of the separate air vessels, which are to consist of
entirely welded cylinders with curved ends, and set in seats provided for them in
the framing.
My present Invention also comprises an improvement relating to the handing
details, which consists in working all the various rods or levers that have to be
moved by hand by means of a set of vertical spindles arranged in one pedestal at
the end of the carriage. If there are sets of handing details at each end of the
carriage a hood or casing may be provided for covering the hand wheels and levers
at one end when the driver is at the other end.
Figure 3 is a plan as with the hood 5 removed of a set of handing details, thus
fitted in and upon a single pedestal 6.
Figure 4 is a vertical section of the pedestal, and shows some of the details, and
Figure 5 shows some parts which are in front of those shown in Figure 4.

page_text: Figure 6 is a vertical section, each half of which is taken nearly at right angles to
Figure 4, and Figure 7 is a horizontal section.
Of three handles which are above the top 7 of the pedestal, one, 8, is for letting
on and shutting off the compressed air, and is fixed to a rod 9, which passing down
a tube 10 is fixed to the spindle 11 of the regulator valve, the box 12 of which is
shown; the second handle 13 is fixed to the tube 10, and by it and through spur
wheels 14 gives motion to the spindle 15 of a small valve 16, which is for admitting
air to the main slide valve independently of the cut-off valves, and so as to facilitate
the starting of the engines in certain positions of the valves. The small pipe 17
from the valve 16 communicates with a passage at each end of each cylinder port
face.
Figure 2 is a longitudinal section of one end of a port face, and shows the
passage 18 referred to, and to it a small perforation is made from the port face in
a position to admit compressed air into the through port 19 of the valve whenever
that port is over the cylinder port 20. The third handle 21 at the top of the
pedestal 6 is with a wheel fixed on a vertical shaft 22 which is geared by bevil
wheels 23 to a horizontal shaft 24 arranged to act on the cut-off valve adjusting
details. A screwed part of the shaft 22 acts on an index 25, which projecting
through a slot in the side of the pedestal shows the position of the cut-off details.
At the sides of the upper part of the pedestal 6 there are two hand wheels 26, 27,
on short horizontal spindles, which by bevil wheels 28, 29, give motion to two
vertical rods 30, 31. The lower ends of these rods 30, 31, are screwed and tapped
through swivelling blocks in bell-crank levers 32, 33, which turn on a fixed hori-
zontal spindle 34, and act on horizontal rods 35, 36. One of these hand wheels 26
with the parts in connection 30, 32, 35, is for acting on the brakes, and the other
hand wheel 27 with the parts 31, 33, 36, in connection with it is for acting on the
valve reversing gear. The lower reversing rod 36 is connected to its bell-crank
lever 33 by a gab notch, and when the carriage is fitted with two sets of handing
details it is necessary to disconnect the rod 30 of the set which is not being acted
on, and this is done by lifting the rod off the pin of the bell-crank lever by means
of a rod 37 jointed to its end, and passing up to a small handle 38 at the top of
the pedestal. This handle 38 is held when drawn up by turning it so that a pro-
jection formed on its side may rest on the boss on the top plate 7. The bell-crank
lever 33 of the reversing details has jointed to it a rod 39, which has attached to
its upper end an index moving in a slot 40 formed in the side of the pedestal 6, and
this index shows the position of the reversing bell-crank lever 33. The handles of
the hand wheels 26, 27, are jointed to the wheels, and can be turned down into
notched projections on the side of the pedestal so as to lock the wheels, and also to
allow of the hood or casing being placed on the pedestal.
Having thus particularly described my said Invention, and the manner of per-
forming the same, I have to state that I do not restrict myself to the precise details
herein described and delineated, but that what I believe to be novel and original
and claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,-
1. The fitting of the cylinders of locomotive carriages worked by compressed air
with check valves for admitting external air, substantially as and for the purpose
herein-before described.
2. The connecting of the driving axle of a locomotive carriage worked by com-
pressed air with the first motion shaft by variable frictional or toothed gearing,
substantially as and for the purpose herein-before described.
3. The adjusting of variable cut-off valves of locomotive carriages worked
by compressed air by means of speed governors, substantially as herein-before
described.
4. The arranging of a complete set of the handing details of a locomotive
carriage worked by compressed air in and upon a pedestal fitted on the driving

page_text: |platform, or on each driving platform when there are two, substantially as herein-
before described with reference to Figures 3 to 7 of the accompanying Drawings.
In witness whereof, I, the said William Dundas Scott-Moncrieff, have hereunto
set my hand and seal, this Twenty-fifth day of September, in the year
of our Lord One thousand eight hundred and seventy-seven.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
W. D. SCOTT-MONCKIEFT. (L.S.).