Improvements in Pressure and Vacuum Gauges.
Year: 1889

page_text: Date of Application, 27th Dec., 1889
Complete Specification Left, 8th Sept., 1890-Accepted, 27th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in Pressure and Vacuum Gauges.
We, AMILCARE LUSUARDI and ARISTIDE FALCO of Turin, do hereby declare the
nature of this invention to be as follows:-
This invention relates to the combination with a pressure (or vacuum) gauge of a
counter capable of registering the variations of pressure above a given limit and of
preserving the indication of the sum of a these variations. The application of this
invention to a pressure gauge is shewn in the annexed drawings in which
Fig. 1 is a rear elevation of the pressure gauge the cover and part of the framing
being removed.
Fig. 2 is a vertical section ;
Fig. 3 is an elevation partly in section shewing some of the parts not shewn in
Fig. 1.
The corresponding parts in all the figures are marked with the same reference
figures.
Referring to Figs. 1 and 2, within a box A is a pressure gauge tube B that
operates by any well known means, the needle C which indicates the pressure on a
dial at the front of the apparatus. The needle C, or it may be its pivot C¹ carries an
arm (which is compelled to follow the movement of the needle.
When the pressure
reaches the predetermined limit this arm C¹¹ comes into contact with one end of a
lever D mounted, so as to turn with small friction, on the shaft of a ratchet wheel E.
A pawl or spring F fixed to the lever D abuts against the teeth of the wheel E and
causes it to turn with the lever when the latter is moved by the arm (When the
lever D moves back, the pawl or spring F slides over the teeth of the wheel E which
cannot turn backward by reason of the detent G fixed upon the framing of the
apparatus. The position of the lever D when the arm is not touching it, is
regulated by means of the stop H against which it is brought by the spring D'. The
stop H can slide in a slot H' within which it can be fixed at any desired point. The
ratchet wheel E is connected to a disc or dial E¹ that carries at its front side a
graduated scale which can be observed or read off through an opening I (Figs. 2 and 3)
in the dial of the pressure gauge.
The operation of the apparatus is as follows:-
The stop H is so fixed that the arm will abut against the lever D when the
pressure has reached the given limit. As long as the pressure remains below that
limit, the pressure gauge will operate in the ordinary manner; but if the limit of
pressure be exceeded, the arm C will push the lever D which will move with it the
wheel E and the disc E', and will cause the latter to indicate the excess of pressure ;
the needle C will however continue to indicate the pressure as usual.
When the pressure diminishes, the arm C will leave the lever D, which will be
brought back against the stop H by the spring D' but the disc E' will remain in the
position into which it has been moved and will preserve the indication of the excess
of pressure.
Should the pressure again exceed the limit, the disc will be again moved to an
extent corresponding to the excess of pressure and this new indication will be added
to the preceding one, in such a manner that the graduated scale on the disc will show
at all times the sum of the fluctuations of the pressure above the desired limit.
In order to increase the range of the indications that can be registered by the
apparatus, one or more dials may be employed to register the number of complete
revolutions of the disc E'; for this purpose any known arrangement may be employed

page_text: but it is considered advantageous to employ the arrangement illustrated in Fig. 3
which is as follows:-
Upon the shaft of the disc E' and ratchet wheel E, is fixed a cam L that moves
with these parts. This cam at each revolution raises the tooth M¹ of an elastic lever M
of which the end M" slides over the inclined face of one of the teeth of a wheel N and
then falls into the hollow of the next tooth during which time a spring detent O
prevents the wheel N from turning backward.
accomplished a revolution the cam L passes beyond the tooth M', and the lever M
At the moment when the disc E' has
returning by reason of its own elasticity pushes the wheel N by its end M" and causes
it to advance to the extent of one tooth. A graduated scale is marked upon or fixed
to the wheel N in any suitable manner and serves to indicate the number of
revolutions of the wheel E.
In order that the person or persons in charge of the apparatus which it is desired
to control by means of this pressure gange shall not be tempted to annul the indications
of the gauge and to bring the scale back to its initial position by causing it to advance
by oscillations of pressure produced purposely, it is advantageous that the graduated
scale of the disc E', or that of the wheel N, or both, should be hidden from his or
their view. For instance in the annexed drawings, the graduated scale of the wheel N
is visible only through an aperture P (Figs. 2 and 3) adapted to be closed by a
plate P which may be fastened by means of a padlock or a lead or other seal, or in
any other suitable manner.
the cover of the box A and also all the cocks and joints of the pipe connecting the
It will also be advantageous to secure in a similar manner
pressure gauge to the apparatus to be controlled.
Although the annexed drawings shew the application of this invention to a well
known form of pressure gauge, this invention may be applied to pressure gauges or
vacuum gauges of various kinds made of metal, whatever may be the form of the
part employed for measuring the pressure, such as a tube, drum, or box, and whatever
may be the arrangement used for transmitting the movement to the needle; and
further whether the latter moves in a straight line or in an arc of a circle, or whether
it makes a complete revolution. In the latter case it is desirable to arrange the shaft
of the disc E on the prolongation of the shaft of the needle and it will be necessary
to slightly vary the form of some of the parts, but the operation of the apparatus will
remain the same.
In some cases it will be advantageous to add a second needle for the purpose of
preserving the indication of the maximum pressure; this may be done by means of
any known arrangement.
As will be obvious the details of construction may be variously modified and we do
not limit ourselves to the exact form of the parts as illustrated provided the essential
nature of the invention be retained.
Dated this 24th day of Decembar 1000.
A. LUSUARDI,
Per L. W.
A. FALCO,
Per L. W.
COMPLETE SPECIFICATION.
Per L. W.
Improvements in Pressure and Vacuum Gauges.
We, AMILCARE LUSUARDI and ARISTIDE FALCO of Turin, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
This invention relates to the combination with a pressure (or a vacuum) gauge of a
counter capable of registering the variations of pressure above a given limit and of
preserving the indication of the sum of all these variations. The application of this
invention to a pressure gauge is shewn in the drawings filed with our Provisional
Specification and in which
Fig. 1 is a rear elevation of the pressure gauge, the cover and part of the framing
being removed.

page_text: Fig. 2 is a vertical section:
Fig. 3 is an elevation partly in section shewing some of the parts not shown
n Fig. 1.
The corresponding parts in all the figures are marked with the same reference
igures.
Referring to Figs. 1 and 2 within a box A is a pressure gauge tube B that
operates by any well known means, as by the link shewn, the needle which indicates
the pressure on a dial at the front of the apparatus. The needle C, or it may be its
pivot C, carries an arm C which is compelled to follow the movement of the needle.
When the pressure reaches the predetermined limit, this arm comes into contact
with a pin projecting from one end of a lever D mounted so as to turn with very little
A pawl or spring F fixed to the lever D
friction, on the shaft of a ratchet wheel E.
abuts against the teeth of the wheel E and causes it to turn with the lever when the
latter is moved by the arm (". When the lever 1 moves back, the pawl or spring F
slides over the teeth of the wheel E which cannot turn backward by reason of the
detent G fixed upon the framing of the apparatus. The position of the lever D when
the arm is not touching it, is regulated by means of the stop H against which it
is brought by the spring D¹. The stop H can slide in a slot H within which it can
be fixed at any desired point. The ratchet wheel E is connected to a disc or dial E¹
that carries at its front side a graduated scale which can be observed or read off
through an opening I (Figs. 2 and 3) in the dial of the pressure gauge.
The operation of the apparatus is as follows:-
The stop H is so fixed that the arm C will abut against the lever D when the
As long as the pressure remains below that
pressure has reached the given limit.
limit, the pressure gauge will operate in the ordinary manner; but if the limit of
pressure be exceeded, the arm will push the lever D which will move with it
the wheel E and the disc E, and will cause the latter to indicate the excess of
pressure; the needle C will however continue to indicate the pressure as usual.
When the pressure diminishes, the arm (will leave the lever D, which will be
brought back against the stop H by the spring D¹ but the disc E' will remain in the
position into which it has been moved and will preserve the indication of the excess
of pressure.
Should the pressure again exceed the limit, the disc will be again moved to an
extent corresponding to the excess of pressure and this new indication will be added
to the preceding one, in such a manner that the graduated scale on the disc will
shew at all times the sum of the fluctuations of the pressure above the desired
limit.
In order to increase the range of the indications that can be registered by the
apparatus, one or more dials may be employed to register the number of complete
revolutions of the disc E'; for this purpose any known arrangement may be employed,
but it is considered advantageous to employ the arrangement illustrated in Fig. 3
which is as follows:-
Upon the shaft of the disc E¹ and ratchet wheel E, is fixed a cam L that moves
with these parts.
This can at each revolution operates the tooth M of an elastic
arm or lever M of which the end M slides over the inclined face of one of the teeth
of a wheel N and then falls into the hollow of the next tooth during which time a
spring detent prevents the wheel N from turning backward. At the moment
when the disc E has accomplished a revolution the cam L passes beyond the
tooth M', and the arm or lever M returning by reason of its own elasticity pushes
0 the wheel N by its end M" and causes it to advance to the extent of one tooth. A
graduated scale is marked upon or fixed to the wheel N in any suitable manner and
serves to indicate the number of revolutions of the wheel E.
In order that the person or persons in charge of the apparatus which it is desired
to control by means of this pressure gauge shall not be tempted to annul the indi-
5 cations of the gauge and to bring the scale again to its initial position by causing it
to advance until it has accomplished an entire revolution by oscillations of pressure
produced purposely, it is advantageous that the graduated scale of the disc E', or

page_text: that of the wheel N, or both, should be hidden from his or their view. For instance
in the annexed drawings, the graduated scale of the wheel N is visible only through
an aperture (Figs. 2 and 3) adapted to be closed by a plate P¹ which may be
fastened by means of a padlock or a lead or other seal, or in any other suitable
manner. It will also he advantageous to secure in a similar manner the cover of
the box A and also all the cocks and joints of the pipe connecting the pressure
gauge to the apparatus to be controlled.
Although the annexed drawings shew the application of this invention to a well
known form of pressure gauge, this invention may be applied to pressure gauges or
vacuum gauges of various kinds made of metal, whatever may be the form of the
part employed for measuring the pressure, such as a tube, drum, or box, and what-
ever may be the arrangement used for transmitting the movement to the needle; and
further whether the latter moves in a straight line or in an arc of a circle, or whether
it makes a complete revolution. In the latter case it is desirable to arrange the
shaft of the disc E on the prolongation of the shaft of the needle and it will be
necessary to slightly vary the form of some of the parts in an obvious manner, but
the operation of the apparatus will remain the same.
In some cases it will be advantageous to add a second needle for the purpose of
preserving the indication of the maximum pressure; this may be done by means of
any known arrangement.
As will be obvious the details of construction may be variously modified and we do
not limit ourselves to the exact form of the parts as illustrated, provided the essential
nature of the invention be retained.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The combination with a pressure (or a vacuum) gauge of a counter capable of
registering the variations of pressure above a given limit, the said counter comprising
essentially an arm C actuated by the indicating needle of the gauge, a lever I
adapted to be operated by the said arm, and a wheel E that is operated by the said
lever, together with the respective springs and other accessory parts, substantially as
herein before described and illustrated.
2. In a registering pressure or vacuum gauge, apparatus for registering the number
of revolutions of the first wheel of the counter and comprising essentially a cam L
operated by the said wheel, an elastic arm or lever M against which said cam acts
and a toothed wheel N actuated by the said elastic arm or lever with their
accessory parts, substantially as hereinbefore described and illustrated in Fig. 3 of
the drawings.
3. The combination and arrangement of parts referred to in the preceding claims,
and constituting our improved registering pressure gauge, constructed and operating
substantially in the manner herein before described with reference to and illustrated in
the drawings for the purpose specified.
Dated this 8th day of September 1890.
AMILCARE LUSUARDI,
Per L. W.
ARISTIDE FALCO,
Per L. W.