IMPROVEMENTS IN PRESSURE GUAGES
Year: 1858

page_text: LETTERS PATENT to Jules le Franc, of 58, Aldersgate Street, for the
Invention of "IMPROVEMENTS IN PRESSURE GUAGES."-A communication
from Jules Rival, of Paris.
Scaled the 17th September 1858, and dated the 20th March 1858.
PROVISIONAL SPECIFICATION left by the said Jules le Franc at the
Office of the Commissioners of Patents, with his Petition, on the
20th March 1858.
I, JULES LE FRANC, of 58, Aldersgate Street, do hereby declare the nature
of the Invention for "IMPROVEMENTS IN PRESSURE GUAGES," to be as follows:-
This Invention has for its object improvements in pressure guages.
For
these purposes a closed vessel partly filled with quicksilver is used, in which
there is a float, or it may be a body partly immersed in the quicksilver, to which
float or partly immersed body there is attached a rod which passes through the
cover or top of the vessel, and such rod is connected with another rod; which
at its upper end is formed with teeth which give motion to a toothed' wheel on
the axis of a pointer, which indicates on a circular graduated dial the degree of
pressure the apparatus is at any time subjected to. The float or the immersed
body, and consequently the toothed rack, is actuated by a lever, so as to press
the float into the quicksilver, or more or less to raise the body immersed in
the quicksilver. The lever which acts. on the partly immersed body or float is

page_text: pressed on by a piston, which receives the pressure to which the apparatus is
subjected. The piston works in a small cylinder affixed at the upper end of a
bent tube which is filled with water, and the piston may be arranged to act on
the lever between its fulcrum, which is capable of adjustment, and the partly
immersed body, or beyond the fulcrum, so as to press the float into the quick-
silver. The toothed rack is to be suitably geared with the toothed wheel to
cause the pointer to revolve in the proper direction.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Jules le Franc in the Great Seal Patent Office on the
20th September 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JULES LE
FRANC, of 58, Aldersgate Street, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of March, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Jules le Franc, Her special licence that I, the said Jules le Franc,
my executors, administrators, and assigns, or such others as I, the said
Jules le Franc, my executors, administrators, and assigns, should at any
time agree with, and no others, 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 PRESSURE GUAGES," (a communication from Jules Rival, residing at Paris,)
upon the condition (amongst others) that I, the said Jules le Franc, my
executors or administrators, by an instrument in writing under my, or their,
or one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Jules le Franc, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object improvements in pressure guages. For

page_text: these purposes a closed vessel partly filled with quicksilver is used in which
there is a float, or it may be a body partly immersed in the quicksilver, to
which float or partly immersed body there is attached a rod, which passes
through the cover or top of the vessel, and such rod is connected with another
rod, which at its upper end is formed with teeth, which give motion to a
toothed wheel on the axis of a pointed, which indicates on a circular graduated
dial the degree of pressure the apparatus is at any time subjected to. The
float or the immersed body, and consequently the toothed rack, is actuated by
a lever, so as to press the the float into the quicksilver, or more or less to raise
the body immersed in the quicksilver. The lever which acts on the partly
immersed body or float is pressed on by a piston which receives the pressure
to which the apparatus is subjected. The piston works in a small cylinder
affixed at the upper end of a bent tube, which is filled with water, and the
piston may be arranged to act on the lever between its fulcrum (which is
capable of adjustment) and the partly immersed body, or beyond the fulcruin,
so as to press the float into the quicksilver. The toothed rack is to be suitably
geared with the toothed wheel, to cause the pointer to revolve in the proper
direction.
Having thus stated the nature of the said Invention, I will proceed more
fully to describe the manner of performing the same.
DESCRIPTION OF THE DRAWING.
Figure 1 shews an apparatus combined according to the Invention; Figure 2
is a vertical section thereof; and Figure 3 shows a plan. In each of these
Figures the same letters indicate similar parts. a is a vessel containing quick-
silver; b is a body of cast iron or other suitable material, to which, at its
upper end, is fixed a rod c, which passes freely through an opening in the
cover of the vessel a. .The rod c is connected to another rod d by a link e and
pin joints. f is a lever, which is pin-jointed at one end to the rod c. The
rod d at its upper end has a rack g formed thereon, or fixed thereto, the teeth
of which rack take into and give motion to a toothed pinion
the pointing hand j. As the pressure which acts on the
greater and greater as the weight or body b is raised more and more out of the
quicksilver, the pointing handj will be caused to move more and more from
zero, and the extent of such movement of the hand will be shown by the fixed.
dial. The pressure is caused to act on the lever f in the following manner:-
I is a bent tube, which is kept full of water, and such tube is to be attached
to a steam boiler when it is desired to indicate the pressure of steam in
a steam boiler, but this guage, like other pressure guages, may be otherwise
on the axis of
lever f becomes

page_text: employed, as is well understood. The fulcrum or axis of the lever is carried
by the frame m, which slides on the upper part of the standard p, and
it is capable of adjustment thereon by means of screws n and o, o; the
screw n passes through the frame m into the fixed block or standard p; the
screws o, o, pass through the frame, and their ends rest against the upper part
of the block or standard p. The upper part of the standard or block is cut
away to receive the end of the lever between the two sides, and' the two sides
of the standard have slots formed through them, so that the axis of the lever
may be moved to and fro with the frame which carries its two ends of
the axis. The interior of the standard p is hollow, by preference in the form
of a cylinder, and has within it a plug or piston q, the upper part of which
is formed with a projection having a knife edge, or it may be a point or other
suitable surface to come under and act on the lever f; the plug or piston q is
formed to fit the interior of the standard and to slide therein. The plug or
piston rests on a plate or disc r of flexible material, by preference of vulcanized
india-rubber, so that when the water in the bent tube is by the pressure of
steam, or otherwise pressed on, so as to cause the plug or piston to rise in the
cylinder, it will act on the lever and cause its longer end to rise and raise
the body or weight 6 out of the quicksilver.
b
I would remark that it will be evident that in place of using the body or
weight as above described, a float might be employed in place thereof, and
the plug or piston be caused so to act on a lever as to depress the float into
quicksilver, the dial being marked accordingly.
Having thus described the nature of the Invention, and the manner of
performing the same, I would have it understood that I make no claim
to any of the parts separately; but what I claim is the constructing of a
pressure guage by the combination of mechanism as herein described.
In witness whereof, I, the said Jules le Franc, have hereunto set, my
hand and seal, this Tenth day of September, in the year of our Lord
One thousand eight hundred and fifty-eight.
Witness,
E. BARKER.
JULES LE FRANC. (L.s.)