Improvements in and relating to Thermostats.
Year: 1892

page_text: Date of Application, 27th Dec., 1892—Accepted, 11th Feb., 1893
COMPLETE SPECIFICATION.
Improvements in and relating to Thermostats.
I, CHARLES DE ZANG HOWARD, a citizen of the United States of America,
residing at No. 308 Kellogg Street, in the City of Syracuse, County of Onondaga
and State of New York, one of the United States of America, Manufacturer, 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 certain improvements in thermostatic devices for
automatically regulating the temperature in rooms or apartments deriving their
heat from a suitable heating apparatus, or furnace, and it has for its objects,
primarily, to provide a thermostat that will be extremely sensitive in its action, and,
which will act positively to move the draft regulating damper to control the com-
bustion, and also to provide, in connection with said thermostat, suitable mechanism
for accurately operating the damper, and which can be adjusted so as to be operated
when the temperature in the room in which the thermostat is situated reaches any
predetermined point, as more fully hereinafter explained.
The improved thermostat consists essentially of a thermostatic-plate constructed
of two contiguous sheets of a material of different expansible properties, the said
plate being formed with a broad base which is securely fastened to any suitable
support, and a gradually narrowed body, the end opposite the base being free to
move under the expansion and contraction of the thermostatic plate so as to permit
the damper to move automatically, in one direction as the thermostatic-plate is
expanded, and to move it positively in the opposite direction as the said plate
contracts under changes of temperature, as will be more fully hereinafter specified.
The invention further consists in the combination with the thermostatic-plate of
certain mechanism connecting the same with a damper, whereby the damper may
be automatically operated by the expansion and contraction of the plate, as more
fully hereinafter set forth; and the invention finally consists in the combination and
arrangement of the thermostatic-plate, the operating mechanism, and the damper, as
more fully hereinafter set forth.
In the accompanying drawings, making part of this Specification-
Figure 1 represents a front elevation of the improved thermostat, detached.
Figure 2 represents a vertical section of the thermostat.
Figure 3 represents a perspective view of a damper.
Figure 4, a sectional view of a structure showing two compartments in which the
thermostat and heating apparatus are located, respectively, and
Figure 5 a detail view of the upper part of the standard.
Referring to the drawings, the numeral 1 indicates a thermostatic-plate, which is
constructed of two contiguous sheets of material having different expansible
properties. By preference, sheet iron, as A, and hard rubber or vulcanite, as B,
are employed for the purpose. These sheets are firmly united by rivets or otherwise,
and are of such shape as to afford a broad base, capable of being rigidly fastened
to any suitable support, the body of the thermostatic-plate being gradually
narrowed to an apex with which the damper controlling mechanism is connected.
In the present instance the thermostatic-plate is represented as of triangular shape,
and has its base secured to the base 2 of a vertical standard, 3, which is about
equal in length to the height of the thermostatic-plate. The base of the standard
is perforated as indicated by the numeral 4 so that it may be attached, by means of
a screw, to the wall of the room or apartment in which the thermostat is located..

page_text: At the base of the thermostatic-plate, is, preferably, located a transverse bar, 7,
which increases its rigidity without materially adding to its weight, or impairing its
power of contraction and expansion. The thermostatic plate is fastened to the
front of the standard, so that its upper free end, under the influence of expansion
and contraction, will move to and from the upper end of said standard.
The upper end of the standard is provided with an opening or slot, 8, having
bearings at each side, between which is adjustably fulcrumed a bell crank lever, 9;
to the short vertical arm 10 of which is secured one end of a short link or chain 11;
the said chain passes through a guide 12, fastened to the apex or narrow upper end
of the thermostatic plate, and is secured to the wrist pin 14, of a short crank
arm 15, secured to the inner end of a short shaft 16, passing through a bearing 17,
at about the center of the thermostatic plate, the front end of the shaft being
provided with a knob 18, and a pointer, 19, the latter being adapted to move over
a scale 20 on the front face of the thermostatic-plate. By turning the shaft, the
chain is shortened or lengthened to set the thermostat so as to operate at a
predetermined or desired temperature.
To the long or horizontal arm 21 of the lever is attached one end of a cord or
extension 22, the other end of which is connected with the damper to be controlled
by the thermostat.
The damper may be of any suitable construction, but is, preferably, in the form
shown in the drawings, in which the numeral 23 indicates an outer air casing, which
is of cylindrical shape and constructed of any suitable material. The numeral 24
indicates an outer cylinder which is supported concentrically and longitudinally
within the casing proper by means of the annularly slotted heads 25, fitted upon
the ends of the outer casing. The heads are provided with outwardly extending
annular flanges 26, to which may be fitted the pipes leading to the ash-pit and the
escape flues of the furnace respectively, as indicated in Figure 3 of the drawings.
The outer cylinder is provided with two sets of peripheral, longitudinal slots
extending from near each end to near the center of said cylinder; those at one end
being, alternately, out of line, longitudinally, with those at the other, for the
purpose more fully hereinafter explained. The heads are provided with diametrical
cross bars, 27, which have central bearings for the axial journals of the damper
cylinder 28, which is located and adapted to partly rotate within the outer cylinder,
before mentioned. The said damper cylinder is slotted to correspond with the slots
in the outer-cylinder, the slots, however, being so disposed, that while those at one
end are registering with the slots at one end of the outer cylinder, the slots at the
other end are out of registration with those at the other end of the cylinder, and
One side of the damper cylinder is weighted, so as to hold the check
side of the damper open, and to this weighted side is attached the end of the cord
or connection, connecting the long arm of the thermostat lever with said damper.
The operation of the invention is as follows:-
vice versa.
The thermostat and furnace being arranged as shown in Figure 4 of the drawings,
and the thermostat being properly adjusted, when the temperature in the room in
which the thermostat is situated rises above a predetermined degree, the thermo-
static-plate will be expanded on the outside and its upper end turned towards the
supporting bracket, allowing the damper to drop on its weighted side, so as to
gradually open the damper openings leading to the flue which enters above the fire
line, so as to retard combustion, at the same time closing the draft or opposite
damper apertures. When the temperature is reduced, the thermostatic-plate con-
tracts, its upper end draws away from the bracket, and the damper is, positively,
drawn in the opposite direction.
It will be perceived that as thus constructed, with a broad base and a narrow
apex, a large and effective heating surface is provided at the lower part of the
thermostatic-plate, by which it is rendered extremely sensitive to changes of
temperature, while at the same time, by reason of the broad base, a powerful
contractile body is obtained.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A thermostatic-plate consisting of two contiguous sheets of material of
different expansible properties, said plate having a broad base fixed to a suitable
support, and a gradually narrowed body in combination with the damper operating
mechanism connected to the narrow end of the plate, substantially as described.
2. A thermostatic-plate, consisting of two contiguous sheets of material of
different expansible properties, said plate having a broad base fixed to a suitable
support and a gradually narrowed body, a supporting standard to the base of
which the base of the thermostatic-plate is securely fastened, a bell crank lever
fulcrumed to the upper end of the standard and a link or chain connecting
the short arm of said lever to the apex of the thermostatic plate, substantially as
described.
3. The combination with the triangular thermostatic-plate, the standard to
which it is secured at its base, and the bell crank lever and its connecting link or
chain, of the crank shaft having a bearing in the thermostatic plate and a knob and
index at its outer end and the chain connecting the crank with the apex of said
plate, whereby the thermostat may be set to operate at a predetermined or desired
temperature, substantially as specified.
4. The combination with the supporting standard, the triangular thermostatic-
plate secured to the same at its base and the bell crank lever and link connecting
the short arm with the apex of the plate, of the damper connected to the long arm
of said lever by a suitable cord or connection, so as to automatically drop as the
thermostatic plate expands, and be moved positively by the contraction of the plate,
substantially as specified.
Dated this Twenty-seventh day of December A.D. 1892.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.