IMPROVEMENTS IN GIVING SIGNALS
Year: 1841

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
HOOD, of Earl Street, Blackfriars, in the City of London, Iron Merchant,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the First day of February, in the fourth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said
Charles Hood, Her especial licence, full power, sole privilege and authority,
that I, the said Charles Hood, my exors, adñiors, and assigns, or such others
as I, the said Charles Hood, my exors, adññiors, 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 GIVING SIGNALS;" in which said Letters
Patent is contained a proviso that I, the said Charles Hood, shall cause a
particular description of the nature of my said Invention, and the manner
in which 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.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Hood, do hereby declare the nature of my Invention, and the
manner in which the same is to be performed, are particularly described and
ascertained in and by the following description thereof, reference being had
to the Drawings hereunto annexed, and to the figures and letters marked
thereon (that is to say):-
My Invention relates, first, to improvements in giving signals by sound, by
means of compressed or condensed air, in the following manner :-The sound
produced by the steam whistle of a high-pressure steam boiler has long been
known as one of the most efficient modes of giving signals, in consequence of
the peculiarity and shrillness of its sound. This sound, however, is not
peculiar to the steam by which it is produced; any other clastic aeriform fluid,
under like pressure, will produce sounds nearly identical. It is well known
that although the engineman who attends the engine of a train of carriages
on a railway has, by the steam whistle, the means of indicating to persons on
the line of railway the coming of an engine, the guards travelling with the
train have no efficient means of giving information or signal to the engine
driver in case of accident, or fire, or any other cause which may render it
desirable that the train should be stopped or retarded; and the object of the
first part of my Invention is, to employ condensed air whistles as a mode of
giving signals by sound, in order to obtain a means of communication with the
engineman, and also for other uses. For this purpose, I employ apparatus
(which may be either portable or fixed to the carriages) consisting of a small
condensing air-pump, attached to a condensing vessel of any convenient form;
into this condensing vessel I pump as much air as will make its elastic force
equal to about three atmospheres, or forty-five pounds per square inch. A
small tube leads from the condensing vessel, ending in a cock, to which is
attached a whistle similar to the steam whistle used on locomotive engines,
except that the apertures are all made smaller than when used, for steam.
On turning the cock, the air passes out from the condensing vessel through the
.whistle, and produces a sound as nearly identical as possible to that of the steam
whistle, but, perhaps, rather clearer, on account of there being in this case no
obstruction to the sound from the condensed steam, technically called the
priming of the steam whistle. The form and dimensions of the apparatus
which I use, and find to answer, are as follows, namely, a metal cylindrical
vessel, about nine or ten inches diameter, and about three feet in length
which is used as a condensing vessel, to which is applied a double-action
pump with a solid plunger, the barrel about two and a quarter inches
diameter, and seven inches stroke, worked by a cranked axis and a rotary

page_text: motion and communicating directly with the end of the condensing vessel;
a pipe of three eighths of an inch internal diameter proceeds from the same
end, or any other convenient part of the condensing vessel, to which pipe is
attached the whistle, with the cock immediately below it. This Invention,
besides its use in communicating signals between the guards and enginemen
on railways, will be extremely useful for steamboats and other vessels, as a
means of giving signals at night, or during foggy weather, and also at
railway stations to give signals at night, and in foggy weather, and on other
occasions. Any number of whistles having different sounds may be combined
in the same apparatus, by which a diversity of signals may be made. I would
remark, that the air may be condensed to a greater or less amount than has
been above described, according as a louder or a fainter sound is required; but
in general a pressure of forty pounds or fifty pounds per square inch will be
required to make the sound sufficiently loud for railway signals, and it is desir-
able at all times to ascertain the degree of pressure by having a common pressure
guage attached to the condensing vessel. To apply this Invention to steam
vessels, the portable apparatus already described may be used, or the condensing
vessel and air pump may be placed in the engine room or other convenient
place, the whistle with the cock being placed upon deck in any situation that
may be convenient, and the pipe of communication between the condenser
and the whistle may be of any length, and proceed in any direction that may
be necessary.
hollow case at the top, containing four
Secondly, my Invention consists in an improved mode of giving signals by a
telegraph in the following manner :-Figures 1, 2, 3, and 4, in the annexed
Drawing, represent a telegraph constructed according to my Invention, which
consists of a strong upright pillar, with a
eaves or pannels, shewn in Figure 2. These four leaves move on an axis
marked z, falling easily into the position shewn in Figure 2, when the cord,
chain, or wire, by which they are drawn up into the frame, is allowed to run
loose. These four leaves are so attached that on pulling the cord, chain, or
wire by which they are fastened (and shewn in the Drawing, Figure
2), the lower, leaf is first drawn behind the second leaf; these two leaves
together are then drawn behind the third leaf, the three leaves are then
drawn behind the fourth leaf, and lastly the four leaves are all drawn into
the hollow case, assuming the position shewn in Figure 4. The use of this
apparatus is to give signals on railways, the four leaves being made to indicate
such arbitrary signs as may be determined upon. Thus each leaf may be
painted a different color, and the lowest leaf, which is visible, shall indicate
what is required, such as ordering the engine driver of a coming train to stop.

page_text: to reduce his speed, to proceed cautiously, or any other previously determined
arrangement. When used in this way, the raising or lowering of the leaves
may conveniently be performed by hand by means of a rope or chain passed
down the pillar and attached to the leaves, as will readily be understood on
examining the Drawing. But its principal use will be at or near stations, to
give notice to the drivers of trains whether they may approach or proceed
with safety. Figures 1, 2, 3, and 4, represent different views of a telegraph
for this purpose. It is supposed to be about twenty feet high, and to be fixed
at some distance, say, perhaps one hundred yards in advance of the station on
that line of rails where trains approach. It may be worked by hand, as
already described, or the following arrangement of machinery may be applied
which will prevent mistakes occuring from any neglect in placing the signal
in its proper position. Figures 5 and 6 shew a front view and a plan of the
wheelwork of the machine. C is the first or great wheel, on the axis of
which a barrel or pulley L, with a weight for a prime mover, is fixed. The
wheel C contains sixty-three teeth, and goes round in one quarter of an hour,
working into a pinion of seven leaves, and which pinion therefore makes nine
revolutions in a quarter of an hour. On the axis of this pinion is fixed the
escapement wheel B of fifty teeth, which vibrates seconds, with the usual
length of pendulum, making one hundred vibrations or seconds in one revolu-
tion, or three thousand six bundred vibrations in an hour. On the axis of
the wheel C is fixed a pulley M, of nine inches diameter, connected by a belt
to a small pulley .N, of three inches diameter, fixed on the same axis.as the
drum D, which makes three-revolutions for one of M. From the drum D, of
twenty inches diameter, a belt passes over a loose pulley K, of five inches
diameter (which works loose on the axis of E and K³, not yet described),
which makes four revolutions for one of D, and to which loose pulley K is
attached a sheave pulley, of twelve inches diameter, connecting the fly wheel
or tappet motion F by a small shcave pulley of three inches diameter, making
the fly wheel or tappet motion F revolve sixteen times for one of D, and
forty-eight times for one of C, the tappet motion continually striking the
crank, as shewn in Figure 6, and ringing the bell I for any required length of
time. When the belt is thrown off from the loose pulley K.to the pulley K³
(which is of the same diameter, but fixed to the axis), the tappet motion K
becomes still..and the drum E-revolves with the fixed pulley.K2, and winds
the cordl, chain, or wire rope, which passes from.it to the pulley P, fastened to
the bottom of the post to which the signal leaves are fixed, and draws up the
several leaves of the telegraph gradually until they assume, the position shewn
in Figures 3 and 4. By shifting the belt back again from K' to K (its

page_text: original position), the drum E will be set loose, and by raising a small detent
fixed to the wood frame the drum E will run round the reverse way and
uncoil the cord, chain, or wire rope, and allow the signal leaves to assume the
form shewn in Figure 2, the leaves being projected from the case by a
spring attached to the back of the frame or box in which they are contained.
The size of the drum E being proportioned to the radius of the signal leaves,
the latter can be made to wind up gradually in any required time. If, there-
fore, the leaves be marked conspicuously with large figures, the bottom leaf
may be made to shew the time which has elapsed since the previous train
passed. Thus, suppose on a train stopping at a station the bell be set in
motion, as already described, and as soon as the train again starts the belt be
shifted to move the drum E, then, if each leaf requires three minutes for wind-
ing up, at the end of three minutes the lower leaf will be wound up even with
the second leaf, which being marked 3, will shew that the train has only
passed three minutes. Both these leaves will then continue to rise together
until at the end of six minutes they will assume the position shown in Figure
3, indicating that the preceding train has passed six minutes, and so on, until
the leaves are all wound up into the case. When the weight which 'moves
the machinery is run down, it is to be wound up again by the arbor x in a
contrary direction round a drum L, which latter is attached to C by a ratchet
wheel and click, similar to the common winding power of a clock. For tho
purpose of using this Invention as a night signal or in foggy weather, the
several leaves may each have a pane of glass let in as follows:-Suppose
the figures to be exhibited are required to be six inches square, the figures 3,
6, and 9, as already described, should be painted on white glass on the second,
third, and fourth leaves from the bottom respectively. The glass in the fourth
or upper leaf must be large enough to shew the figure 9, but the third leaf
(or the one below) must be six inches longer, and the figure belonging to that
leaf (namely, 6) must be placed six inches near to the extremity of the leaf;
and Figure 3 on the second leaf must be placed twelve inches nearer the
extremity, and the glass must be twelve inches longer than the fourth leaf.
Then, if the lowest leaf have a pane of red glass the same size as the pane of
white glass in the second leaf, and a lamp be fixed behind the glass, the
leaves as they gradually rise will shew only one figure at a time, answering to
the figures marked on the leaves in Figure 2. In order that these respective
figures may be visible so long as possible until another figure be brought into
view, it will be desirable that they be placed as near to the axis of the signal
leaves as may be convenient, and that the panes of glass extend as far across

page_text: the leaves as possible, by which means nearly a continuous light will be shewn,
and the figures remain much longer in view. A lamp with a powerful
reflector should also be placed so as to throw the light strongly on the front
of the leaves.. In this apparatus I do not confine myself to this exact form or
arrangement described, or to any particular number or form of the leaves
or pannels, or to any particular color of the leaves or material for their con-
struction, nor is it necessary the leaves or pannels should all move on one
axis, nor that they should rise separately in the manner described.
The
apparatus is capable of being made in a variety of.forms. The leaves may very
conveniently be made to describe an arc of 90° instead of the arc of 45°, as
shewn in the Drawing; and by additional leaves may, when placed between the
two lines of rails, give different signals at the same time to trains passing on
the two separate lines of rails; or the leaves may be made to act the reverse
way to that shewn in the Drawing, the points of suspension being at the top.
In this case the leaves will be drawn up at once into their extended position,
and the clock movements of Figures 5 and 6 will then act by allowing the
leaves to descend by gravity, the velocity of descent being regulated by the
pendulum motion and escapement wheel already described. The power which
acts upon the leaves may either be applied directly to the axis or axes of the
leaves, or at the extremity, or at any intermediate point between the axes
and the extremity.
Having now described the several parts of my Invention, and the way
in which it may be carried into effect, I would have it understood that what I
claim is,―
First, the mode of giving signals by applying condensed air in apparatus in
combination with whistles, as herein described.
And, secondly, I claim the mode of giving telegraphic signals on railways,
by means of moveable leaves or pannels, worked either by hand or by
machinery or by both means conjointly, in the manner above described, and
combining therewith clock movements or other similar machinery for pro-
ducing a gradual and ascertained velocity of motion in the leaves or pannels
of the telegraph, and for the continuous sounding of an alarm bell, in the
manner described.
In witness whereof, I, the said Charles Hood, have hereunto set my hand
and seal, this Twenty-eighth day of July, in the year of our Lord
One thousand eight hundred and forty-one.
CHARLES (L.S.) HOOD.

page_text: AND BE IT REMEMBERED, that on the Twenty-eighth day of July,
in the year of our Lord 1841, the aforesaid Charles Hood came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.
Inrolled the Thirty-first day of July, in the year of our Lord One
thousand eight hundred and forty-one.