IMPROVEMENTS IN ATMOSPHERIC RAILWAYS
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
HARLOW, of Paradise Street, Rotherhithe, in the County of Surry, Carpenter,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent, under the Great Seal of Great Britain, bearing
date at Westminster, the Tenth day of October, in the ninth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Frederick Harlow, my exors, admors, and assigns, Her especial
licence, full power, sole privilege and authority, that I, the said Frederick
Harlow, my exors, admors, and assigns, or such others as I, the said Frederick
Harlow, my exors, admors, or assigns, should at any time agree with, and no
others, from time to time and at all times during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, my Invention of
"IMPROVEMENTS IN ATMOSPHERIC RAILWAYS;" in which said Letters Patent is
contained a proviso that I, the said Frederick Harlow, shall cause a particular
description of the nature of my said Invention, and in what manner the same
is to be performed, to be inrolled in Her said Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Frederick Harlow, do hereby declare that the nature of my said Invention, and

page_text: in the various fig
parts.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a plan of part of the traction pipe of an atmospheric railway,
having a valve applied thereto according to my Invention. Figure 2 is a
transverse section of the pipe and valve. Figure 3 shows a plan, a section,
and an edge view of part of the longitudinal valve. Figures 4 and 5 show
plans of parts of the valve where two parts are joined, the spring in the one
case being extended, and in the other case it is shown compressed; and
Figure 6 shows the details of the parts used at the joints where the parts of
the valve come together. The peculiarity of the valve is that it is a sliding
valve made up of pieces so connected as to be air-tight at the junctions, and
yet allow of movement to the separate parts, in order to the passage of the bar
which connects the piston with the carriage. a, a, a, are parts of the valve.
At the ends of each of the pieces a of the valve there is a semi-circular recess,
into which spaces, where two ends come together, are placed two discs of metal
b, b, and a disc of leather or other elastic packing c, having projecting pieces
at c', as shown, which pass to the edges of the valve, and are the means of
making the joint air-tight laterally. On each of the pieces a of the longitudinal
valve is formed or affixed a hook d, the nature of which is shown in the
Drawing, and these hooks pass through the coupling pieces e, the construction
of which is fully shewn in the Drawing, there being a semicircular ring of
packing at e', pressed against by a spring, which is shown in the section at
Figure 6. f, f, are springs which constantly press the backs of the coupling
pieces, with a tendency to keep the valve closed, there being a surface of
leather or other suitable flexible matter at g, against which the edge of the
valve presses. In order to keep out snow or other matter, a cover his
fixed, as is shown, with the bar i, which comes in contact with the upper

page_text: surface of the valve. As the piston travels along the valve is slided back, but
closes again soon after the bar or instrument (which connects the carriage
with the piston) has passed. Figure 3* shews a slight modification of the
sliding valve, the difference being that there is but one disc of metal used at
the joint, and the leather is dispensed with.
I will now proceed to describe the second part of my Invention, which con-
sists of improvements in the construction of pistons for atmospheric railways;
and this part of my Invention has for its object the so arranging the parts of a
piston that it may be used first in one direction and then in the other. j is
the plate or bar which connects the piston with the carriage, and there are
means to communicate by gearing for acting on either end of the piston, so as
to open a communication through one end to the other. Thus, supposing the
piston has just been moving in one direction, the end which has last acted as
the piston may have a passage formed through it, and be contracted in diameter
by the colapsing of the leather packing, and the communication through the
other end of the piston closed. This is accomplished as follows:-k is an axis,
having a bevilled toothed wheel affixed thereon, which takes into and drives the
bevelled toothed wheel on the shaft or axis m. This axis or shaft turns in
bearings at n, and has at each end a cog wheel, which takes into the rings of
teeth o (one at each end of the piston), on the valvular covers o', such covers
being formed with openings o², corresponding with the openings p in each end
of the piston, in which there are also other openings g, so that, supposing the
piston to be travelling in the direction indicated by the arrow, the passages
through the end (1) of the piston would be open (by the openings o' in the
valvular cover o being opposite the openings p), thereby allowing the air in
the tube to act on the end (2) of the piston, to drive it in the direction of the
arrow; and when it is required to have the other end (1) of the piston acted
upon by the atmosphere for the purpose of propulsion, it will only be necessary
to act upon the axis m so as to cause the parts o³ of the cover o' to close the
passages p in the end (1) of the piston, and to cause the openings (0° to be
opposite the openings p in the end (2), and the end (1) of the piston will then
be travelling in the direction of the vacuum.
Having thus described the nature of my Invention, and the best means I
am acquainted with for performing the same, I would have it understood that
I do not confine myself to the details herein described, so long as the peculiar
character of either part of my Invention be retained. But what I claim is,―
First, the mode of constructing and applying longitudinal valves to the
traction pipes of atmospheric railways.

page_text: And, secondly, I claim the mode of constructing pistons for atmospheric
railways.
In witness whereof, I, the said Frederick Harlow, have hereunto set my
hand and seal, this Ninth day of April, in the year of our Lord
One thousand eight hundred and forty-six.