Improvements in Alarm Pressure Gauges
Year: 1895

page_text: Date of Application, 4th Mar, 1895-Accepted, 13th July, 1895
COMPLETE SPECIFICATION.
Improvements in Alarm Pressure Gauges,
I ALBERT EDGAR ALEXANDER of 19 Southampton Buildings, in the County
of Middlesex, 'Chartered Patent Agent, do hereby declare the nature of this
invention (communicated to me from abroad by William Henry Bradt, of
415 Tenth Street, Troy, New York, U.S.A. Engineer, and Melville Marble, of
1513 Fifth Avenue, Troy, New York, U.S.A. Engineer,) and in what manner
the same is 'to be performed to be particularly described and ascertained in and
by the following statement :-
Fig. 1 of the drawings is a front view of an alarm gauge provided with my
improved testing mechanism.
Fig. 2 is a cross-section of same taken on the 'broken 'line 2-2, in Fig. 1.
Fig. 3 and Fig. 4 are views partly in section of a portion of a gauge having
different forms of testing mechanism..
Fig. 5 is a side elevation of the device shown in Fig. 4.
The objects of my invention are to provide an alarm-gauge with mechanism for
testing the contact of the circuit-closing electrodes and the operation of the
battery-circuit; and also for preventing injury to the gauge by the use of such
mechanism.
▲ represents a well known form of pressure-gauge having an index 'A¹ operated
by a Bourden tube A' and intermediate links and levers in the usual manner, a
portion of the tube and one of the links A being shown in Fig. 1.
B is an electric battery which may be of any known form; and C is an electro-
magnetic signal bell located in the battery circuit.
A line-wire B-connects one pole of the battery with the gauge-case at B³, and,
with the case and index shaft A forms a continuona connection between the
battery and the index, the index forming the movable electrode of the circuit-
closing mechanism.
The other electrode is 'formed by the contact-hand D insulated from the index
and having its end offset to form a contact-finger D' in the path of the index.
The contact-hand is pivoted concentrically with the index upon a sleeve 'D²
inserted in the central aperture in the dial surrounding the index-shaft.
The sleeve is provided on its inner end with a shoulder D' abutting on the
under side of the dial, and its upper onter end is screw-threaded to receive and fit
the similarly threaded clamping-nut D' by means of which the contact-hand is
securely clamped to the dial.
The dial, with its contact-hand secured thereto, is insulated from the case of the
gauge and the index in any known manner, as by ineans of the washer D' of rubber
or other insulating material between the dial and case.
A binding-post E is secured in an aperture in the case-wall A' by the nut E¹ on
its inner end, the post and nut being insulated from the case by the insulating
sleeve E and washer E. The inner end of the post is connected by the
conductor E with the dial, and the outer end by the line-wire B' with 'the
remaining pole of the battery, whereby the contact-hand D is connected through
the dial and intervening conductors with such pole of the battery and forms the
fixed electrode of the circuit-closing mechanism.
By loosening the clamping-nut D the contact-hand may be adjusted on the
sleeve to assume any position radial to the dial, whereby the alarm can be operated
|when the pressure reaches any predetermined limit high or low.

page_text: .
The failure of alarm-gauges to operate at critical times is due frequently to the
failure of the battery-current; and often to the electrodes becoming corroded
or coated with oil, dust or other matter which prevents the contact of the
electrodes.
The latter is frequently the case where the gauge-pressure reaches the alarm-
limit at infrequent intervals..
I have shown in the drawings a device which can be applied to an alarm-gauge,
by means of which the electrodes can be brought into contact at. frequent intervals
to close the circuit for testing the battery, and remove and prevent any accumulation
of dust or other. substance upon the electrodes.
K is a link connected at its opposite ends with the vibratory end of the Bourden
tube interiorly of the case, and with the handle K' exteriorly of the case, the
link being passed through an aperture in the case-wall and freely movable
therethrough.
The link may be rigid or flexible, and forms a connection between the handle
and index-operating mechanism, whereby such mechanism can be operated by the
handle.
A sufficient movement can thus be imparted to such mechanism to cause the
index to indicate the alarm degree of pressure, and thereby bring the electrodes
into contact, whereupon the alarm will be sounded if the apparatus is in working
order.
By having the link freely movable through the case-wall aperture, the link is
free to respond to the movements of the tube under varying degrees. of internal
pressure, whereby a rigid link may be employed, if desired, and may be connected.
with the tube without injury to the tube or interference with its operation.
As a means for preventing a straining movement of the parts after the electrodes
have been brought into contact by the testing mechanism above described, I
provide a stop for the testing mechanism.consisting of a screw S inserted in a
threaded aperture.in the case-wall to project interiorly of the case in the path of
the Bourden tube.
The stop can be adjusted to engage the tube when the latter has moved
sufficiently to cause a contact of the electrodes.
..f
The stop will thus prevent further movement which would tend to break or
loosen the index and to strain the tube.
"
In Fig. 31 have shown the hand-mechanism in the form of a rigid link K
pivotally secured at its inner end to the Bourden-tube and having the handle or
head K located without the case. The link is freely movable through the
bushing A inserted in the case-wall aperture; and is screw-threaded near its outer
end to receive and fit the stop-nut S₁ which engages the end of the bushing to
serve as a stop.
:
In Fig. 4 the hand-mechanism for testing the gauge consists of a bar K* fixed
upon the Bourden-tube and freely movable through a slot A' in the case-wall.
The projecting end of the bar forms a handle K' for operating the testing
mechanism.
i
A slotted plate S is secured to the outer side of the case-wall by the screw S
in the path of the bar K' and serves as a stop.
The screw passes through the slot S' in the stop-plate, and the plate can be
easily adjusted by loosening the screw.
The testing mechanism and stop therefor are adapted for use in various forms of
alarm-gauge in which an alarm is given when the pressure reaches a predetermined
limit.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated by .my
foreign correspondents to me, I declare that what I claim is
1. In an alarm-gauge having electrodes arranged to be brought into contact by
the movement of the index-operating mechanism, the combination with the index-
i

page_text: operating mechanism, and apertured case-wall of the gauge, of a handle accessible
from without the case, and a link-connection between the handle and index-
operating mechanism freely movable through the case-wall aperture, substantially
as described.
2. In an alarm-gauge having electrodes arranged to be brought into contact by
the movement of the index-operating mechanism, the combination with the index-
operating mechanism, and apertured case-wall of the gauge, of a handle accessible
from without the case, and a connection between the handle and index-operating
mechanism inserted in the case-wall aperture and having a movement of translation
relatively to the case-wall, substantially as described.
3. In an alarm-gauge, the combination with the case and electrodes arranged to
be brought into contact by the movement of the index-operating mechanism, of
testing mechanism operative from without the case, for bringing the electrodes
into contact, and a stop for limiting the movement of the testing mechanism,
substantially as described.
Dated this 4th dew of March 1905
E. P. ALEXANDER & SON,
Fels. Chartered Inst. Patent Agents,
19 Southampton Buildings, Chancery Lane, London, W.C.,