IMPROVEMENts in Steam Gauges
Year: 1872

page_text: LETTERS PATENT to Joseph Ducomet, of No. 20, Rue des Petits
Hotels, Paris, in the Republic of France, Civil Engineer and Patent.
Agent, for the Invention of “IMPROVEMENts in Steam Gauges.”
COMPLETE SPECIFICATION filed by the said Joseph Ducomet at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 11th June 1872, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
DUCOMET, of No. 20, Rue des Petits Hotels, Paris, in the Republic of
France, Civil Engineer and Patent Agent, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN STEAM GAUGES," and have petitioned Her Majesty to grant unto me,
my executors, administrators, and assigns, Her Royal Letters Patent
for the same, and have made solemn Declaration that I verily believe
myself to be the first and true Inventor thereof.

page_text: E is a plate which is seated on the pillar D, and on which it is held by
means of the screw F and the two steady pins j, k. This plate serves to
hold the arbor 1, the other end of which is supported in an adjusted hole
in the brass block m. This arbor is round and carries a small disc n
formed on it, and shown in Figures 3 and 5. In the disc is a hole o,
Figure 5, through which is passed the end of a metallic or other cord p,
which passes-out and is wound on the arbor l, and is then passed through
E is a plate which is seated on the pillar D, and on which it is held by
means of the screw F and the two steady pins j, k. This plate serves to
hold the arbor 1, the other end of which is supported in an adjusted hole
in the brass block m. This arbor is round and carries a small disc n
formed on it, and shown in Figures 3 and 5. In the disc is a hole o,
Figure 5, through which is passed the end of a metallic or other cord p,
which passes out and is wound on the arbor l, and is then passed through
the сус of a piece q fixed to the rod e by means of the screw 7.
It will be seen that this screw arrangement allows of tightening the
cord p by moving to or fro the piece q.
A vertical spring & screwed at one end on the plate E engages at its
other end into a second hole t in the disc n. By this means the cord p
being wound on the arbor as shewn in Figure 3, and connected to the
piece q, its tension is obtained by pulling the picce q downwards, and
also by the spring & which stretches it. The piece q is then fixed in its
place by the screw 1. Now if pressure is applied under the diaphragm A
the latter will expand, push upwards the button f, and the spring C, O, is
deflected; the rod e which is firmly fixed to the spring is thus moved
forward, but as the piece q is fixed on the rod e it follows the same move-
ment, and the cord p being drawn by the recoil action of the spring s
turns the arbor 1, on which is keyed the indicating hand u, u, which
therefore moves a certain distance over the dial corresponding to the
amount of pressure exercised.
As soon as the pressure ceases or diminishes the spring descends with
the diaphragm, and the cord p being drawn down turns the arbor I, and
the hand returns towards its starting point. By this movement the
springs is again distended. If the pressure is again increased the same
action takes place.
The other parts of the instrument are of ordinary construction,
videlicet, G is the dial on which are marked the required divisions; H is
the flat glass which closes the instrument; v, v, is a ring which is the
connecting piece between the dial and the glass; x, x, flanged ring or
bezzle fitting exactly on the periphery of the box and holding the dial
and glass in their places, and it is fixed to the box by screws.
The novelty of the arrangement herein-before described consists in
fixing on the arbor a disc perforated with a hole for receiving the cord
winding on the arbor. By this arrangement I can employ arbors having

page_text: against this flat surface and prevents the bolt from turning. The screw g¹
being driven home prevents any possible deviation of the bolt, and
thereby keeps the spring at a fixed point. This arrangement also allows
of raising and lowering the spring any required distance, and causes it
to press more or less on the diaphragm. M is a plate fixed on the
pillar K by means of two screws, and serving as in Figure 3 to support
the pivot of the arbor and the tension spring.
Figure 12 shews a bolt cut in the same manner, answering the same
purpose, and held in its place in the same manner as that shewn in
Figures 10 and 11, but its lower end is formed into an angle piece as
shewn at h¹, ; is the plate serving to hold the pivot of the arbor, and
on which is fixed the tension spring; this plate forms the corresponding
angle picce to the angle piece h', ', and is thus made to support the
spring and the pivot. The red lines in this Figure shew that the pillar
may be made in two parts, and then screwed one into the other without
any other alteration.
Figures 13 and 14 shew the spring fixed on an angle piece N, O, P,
which is fixed on the pillar Q by the screw R and two steady pins. This
angle piece also supports the arbor and the tension spring. The red lines
shew how the pillar can be made in two parts and united by a screw.
Figures 15 and 16 shew an arrangement in which the spring and the
arbor are mounted on a piece of the form shewn and fixed to the bottom
of the box by three screws 8,8,8. The arbor and transmitting mechanism
are similar to those herein-before described.
Figures 17 and 18 shew the diaphragm and union fixed on a plate
which is formed into an angle piece fixed to the bottom and periphery of
the box. On this plate is then set up a mechanism similar to that shewn
in Figures 15 and 16.
It will be seen that by this arrangement all the parts may be put
together before being placed in the box, which in this case is very thin
and made of brass. T and U are supports for the spring to prevent it
changing its position.
Figures 19 and 20 shew an arrangement differing only from that last
described in the mode of fixing the union carrying the diaphragm; the
union is screw-threaded and takes into the angle piece of the plate. I
prevent the union moving after being once set in its position by means of
a spur which takes into the bolt and its support.

page_text: It will be easily seen that by enlarging the upper cover the diaphragm
shewn in Figure 27 could be soldered, in which case the screws r¹, §¹,
would not be required.
Figure 29 shews a front view of a steam gauge constructed in this
manner.
In the arrangements shewn in Figures 22, 23, 25, 26, 27, and 28, a
kind of piston is employed which allows of shortening the distance
between the button or piston and the diaphragm in case that distance
should not be exact.
The button or piston y', Figures 22 and 23, is screw-threaded in the
interior, and receives a rod z', also screw-threaded and having a small
shoulder which serves as a seat for the spring. This rod passes through
the spring and passes upwards as seen at n¹. It may be either round or
square, or with rounded angles. To keep it well in its place it may be
screw-threaded at the part above the spring, as shewn in Figures 25
and 26, and fixed by a screw nut a". By this arrangement the piston
may be made to press more or less on the diaphragm by turning it, the
screw thread allowing it to be raised or lowered according to the direction
in which it is turned.
o max ho