IMPROVEMENTS IN BALANCED THERMOMETERS
Year: 1884

page_text: THOMAS PARSONS WATSON of 313 High Holborn in the County of Middlesex,
Optician do hereby declare the nature of the said invention for "IMPROVEMENTS IN
BALANCED THERMOMETERS 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 improvements in the pivotal adjustment of balanced
thermometers, and it has for its object a more accurate and secure suspension of
the oscillating thermostatic tube whereby its adjustment will be facilitated and the
delicacy thereof increased, and other advantages secured therein as hereinafter
described.
It consists mainly in an improved form of bracket and hanger for the balanced
oscillating tube, as hereinafter fully described, and in the combination and connection
of the suspension bracket with the indicating scale of the device independently of
the case, so as to permit of an adjustment of the instrument within the case without
moving or disturbing the latter.
It consists also in the combination of a second graduated face with tho balancod
tube so that while one end of the tube shall serve to indicate the degrees according
to one scale, as for instance the Fahrenheit, the other shall indicate any other desired
scale, as the centigrade, or the Reaumur.
In the accompanying drawings. Figure 1 is an elevation in perspective, on an
enlarged scale, of the improved bracket and banger for the suspension of a
balanced thermometer; figure 5 being a sectional viow, on a still larger scalo in
line x, x, of figure 3, of one of the pivot cups of the bracket.
Figure 2 is an elevation in perspective of a modification in the construction of
the suspension devices. Figure 3 is a front elevation of the improved balanced
thermometer enclosed in a rectangular case which may be immovably affixed to
the wall, and figure 4 is a similar view of a modification of this form of case,
illustrating also the combination of the balanced tube with two scales of different
graduations.
A, represents a thermometer constructed in the usual manner of a glass tube and
bulb properly graduated and within which is enclosed a column of mercury.
B, represents the improved hanger by means of which the thermomoter A is
pivoted. The hanger is struck up between suitable dies from a strip of metal,
and the improvement therein, which is the subject of the invention, consists in
producing between the forked pivot-arms a a of the banger an offset b through

page_text: .
which the adjusting screw c is led, about in line with the two arms of the fork,
so that the three shall fall within the same plane. The lower end of the screw is
swivelled to the end of the lower bearing arm or plate d of the hanger and its
upper threaded end works through a threaded seat or nut in the offset b so that by
turning the screw the upper and lower arms of the hanger are made to approximate
more or less to produce the necessary adjustment of the thermometer A secured to
the lower arm, with reference to its pivot points a a.
The bearing of the hanger upon the tube A, is increased, and the firmness of
its attachment at a right angle to the pivot points more perfectly secured, by
means of lateral lugs or offsets e e, curved and adapted to embrace the top of the
tube when laid therein as shown in figure 1.
The attachment of the hanger to the tube is secured by wrapping them both
with fine wire, although any suitable clamping devices may be employed.
F, represents the improved bracket for supporting the hanger. This bracket is
constructed of a strip of metal stamped and struck up between suitable dies into
the form illustrated in figure 1. Its two ends, bent to stand opposite each other
in line within the same vertical plane when the bracket is properly secured in
place, terminate each in a concaved or conical recess or cup f, adapted to receive
the pointed ends or arms a a of the hanger, and to cause them to gravitate
automatically into their proper position in a plane at right angles to the plane of
the scale over which the index end of the thermometer tube vibrates. This form
of support for the pivot arms, not only ensures their automatic adjustment to the
proper bearing when they are dropped into place, but furthermore furnishes a
receptacle to contain one or more globules of mercury (see figure 5) to ensure
proper electrical contact between the hanger and bracket in case they are to be
included in an electrical circuit arranged to be opened or closed for the purpose of
producing an automatic alarm by the movement of the thermometer. The form
of the bracket F likewise facilitates the support between its curved arms and
underneath the bearing of the thermometer, of a second mercury cup for use in
effecting an electrical contact with the electrodes of an electric alarm circuit.
In the modification shown in figure 2, the bracket arms terminate in knife edges
and the pivotal arms a a, of the hanger are also made to terminate in knife edges
to rest upon and intersect the edges of the bracket arms at a right angle thereto.
In this case the edges of the bracket arnis may be notched in V-shape to
facilitate an automatic adjustment of the edges of the pivotal arms of the hanger
thereto.
The bracket F in the improved balanced thermometer is firmly secured to an
arm M, figure 3, (or a plate Ñ figure 4) which is rigidly attached to, or is integral
with the plate upon which is marked the thennometric scale P of the instrument,
and this scale plate is adapted to be firmly secured to the wall.
In adjusting the thermometer the arm M, or plate N, is turned upon its pivot R,
within the case S without moving the latter, until the index end of the balanced
tube points to the same degree on the scale as is indicated by the column of
mercury upon the thermometric scale marked on said tube.
Tindicates a second scale covered by an index pointer produced from the bulb
of the thermometer and which, if the first scale is graduated to the degrees of
Fahrenheit, may be made to indicate the degrees centigrade or Reaumur.
The blanks for the hanger and the bracket are preferably struck up out of the
finest spring steel and after being properly fashioned are tempered so as to retain
unalterably their shape.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declaro that what
I claim is:
1. The combination in the suspension device of a balanced thermometer, with
the hanger supporting its tube, of an offset produced at the fork of the pivotal
arms of the hanger to receive the adjusting screw and support it in the plane of
Eaid arms, substantially in the manner and for the purpose herein set forth,

page_text: 2nd. In the suspension devico of a balanced thermometer, the combination with
the ends of its supporting bracket, of conical V or cup-shaped seats, adapted to
receive the pivot points of the banger carrying the thermometer and produce
automatically a proper pivotal adjustment thereof, substantially in the manner
and for the purpose herein set forth.
3. The combination with the hanger and the supporting bracket of a balanced
thermometer, and with cup shaped scats in said bracket adapted to receive the
pivot points of the hanger, of globules of mercury enclosed in said seats, substantially
in the manner and for the purpose herein set forth.
4th The combination with an adjustable frame or plate to which are secured the
suspension device and index scale of a balanced thermometer, of an outer stationary
case or frame adapted to be fixed in a permanent position, and within which the
adjustable plate or frame is pivoted, substantially in the manner and for the
purpose herein set forth.
5th. The combination with a balanced thermometer of two differently graduated
index scales corresponding with the respective ends of the thermometer substantially
as shown and described.