A New or Improved Fire Alarm and Heat Indicator.
Year: 1899

page_text: Date of Application, 7th Apr., 1899 -Accepted, 13th May, 1899
COMPLETE SPECIFICATION.
A New or Improved Fire Alarm and Heat Indicator.
I, JAMES DOCKREE, of 43, Lever Street, Goswell Road, London, E.C., Scientific
Instrument Maker, 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:--
My invention relates to a new or improved manner of, and means for, auto-
matically indicating, when a room or other enclosed place becomes heated to a
dangerous temperature, as to cause a fire to ensue, or when the same is to be
kept at a more or less equable temperature such as hothouses or the like, a
sudden climatic change may take place, as to cause excessive heat or cold therein,
and ruination of the plants or the like contained in such places, and has for its
objects, simplicity of construction, adjustment of the points of contact, whereby
an alarm can be obtained at any degree of temperature, immunity from breakage
by reason of all the working parts being constructed of metal, hitherto unknown
with those at present now in use, generally consisting of a glass thermometer,
in which platinum pieces are used to make the electrical connection therein, an-1
these after a time, get corroded by the action of the mercury, rendering such
thermometer inactive and useless, whereas, with my invention mercury is not
employed and therefore obviates such disadvantages; and consists of a curved
compound strip of dissimilar contracting and expanding metals such as brass
and steel soldered together, attached at one end to a pillar fitted with an adjusting
device, and mounted in suitable bearings; having at the other end an arrange-
ment of linkwork, with one or more pillars as supports, the last of which is
suitably extended to enable the boss or centre piece of the indicating hand to be
fixed thereto, by passing through a hole formed more or less at the edge of the
dial or indicator face on the back surface of which a sleeve of short length of
tube is fitted in, and forms an extension of said hole. On this sleeve is attached
two adjustable arms capable of rotating thereon, and also extend across the back
of the before mentioned dial, one end of each appearing through a curved slot
formed therein, whose radius is equal to the length of the said adjustable arms,
Along the edge of said slot a graduated scale of degrees of temperature is marked,
enabling the appearing end of each of the adjustable arms to be set to any degree
of temperature by means of a handle formed at the opposite end of each.
An alarm is caused to be given directly the indicating hand comes in contact
with either of the before mentioned appearing ends, which thereby completes
the circuit of an electric current, having a bell connected therewith.
To enable my invention to be more clearly understood, I have hereunto appended
a sheet of drawings in which:
Fig. 1 is a front elevation of a complete instrument constructed according to
my invention.
Fig. 2 is a horizontal section of same taken on the line 1-2.
Fig. 3 is a side elevation of Fig. 1 with a portion of the enclosing medium,
hereinafter fully explained removed

page_text: Fig. 4 is a similar view to Fig. 1 but has the dial removed and a portion of
the front casing broken away to enable all the working parts to be seen; and
Fig. 5 is a reverse view of a portion of the dial, shewing the manner in which
the adjustable arms are fitted.
..
In bringing my invention into effect I attach to a suitable wooden base A, a
cast iron piece B, by means of screws or the like, and on this is mounted a
pillar C, bome in pivot bearings at each end, and held in position by bracket D.
To the said pillar C is attached a pair of curved compound strips E, F, of dis-
similar contracting and expanding metals, which is called the govenor" each
such strip consisting of a thin strip of brass a on the inner side and steel bon
the outer side thereof, soldered together, and clipped at the opposite end to that of
pillar C, by a bent piece of nickel silver or other suitable metal G, and into this
I screw the projecting piece H, provided with a deep cutting for the reception
of one end of a link J, to enable it to be loosely connected thereto by means of
a pin, the other end being similarly connected by means of a pin j to one end
of an oscillating rod K, this being carried at a suitable part of its length by
pillar I, to which it is connected by any suitable means or formed therewith;
such pillar L being carried in similar bearings to that of pillar C, and retained
in position by bracket M. on cast iron piece B. To the other end of rod K, I
loosely attach by means of pink the link N, and connect this by pin to the
piece O, projecung from a third pillar P, borne at one end only in a pivot
bearing p shewn in Fig. 2; the other end being produced as at q to pass through
bracket R to retain the pillar P in its place, and takes on to its end the boss r
of the indicating hand or pointer Q, but before doing so, it all but passes
through a hole suitably extended by a short length of tube T, formed near the
edge of the silver indicator face or dial S; the said tube T forming on its outer
surface a means for mounting the adjustable arms U, V, each of which can be
made of one metal only such as gunmetal or brass, or as I prefer to construct
them, with the operating handles u, v, enlarged portions u¹, 1, and extending
pieces 22 of either of these metals, and attach to these latter by soldering or
otherwise, arms U, V, of German silver wire, which project across a portion of
the back of the said dial S, and have their points or ends bent forward to
enable them to appear through a slot W formed therein; having at its edge a
graduated scale of degrees of temperature engraved or otherwise marked thereon,
by which each of the said points can be adjusted as desired.
The said dial S, is provided with a glass covering W, and both are mounted
on a suitable frame X, having a portion a, of its inner edge removed to allow
the handles of adjustable arms U, V, freedom of movement; and is attached
to the wooden base A by screws that pass through short lengths of tube or spacing
pieces y, and to one of these is attached a projection y that has threaded there
through a prolonged milled headed screw Y, which is loosely connected by
means of check nuts or the like to the projecting piece 7, screwed to the
pillar C, and forms a means whereby the indicating hand Q. can be adjusted as
desired, through the medium of the govenor E, F, and links connecting same
together.
The space existing between the base A, and frame X, is provided with one
or more windings of silk ribbon Z¹, to protect the interior from dust and dirt,
and allows the slightest change of temperature to pass therethrough to the interior
of the instrument to actuate the mechanism of same.
All the parts where not specially mentioned, I prefer to make of gunmetal,
being least affected by atmospheric or other changes.
Although I have described the govenor as consisting of two compound strips.
I wish it to be understood that I do not confine myself to this number, as I may
find it convenient to use only one or three or four of such strips, according to
the desired sensitiveness of the resulting instrument.
An electric bell and battery are connected with the terminals and s¹ con-
neeted by wires 22 and 2 to the pillar P, and a small studs respectively; the

page_text: the
latter being fixed to the back of the dial S; the circuit being completed directly
the indicating hand Q comes in contact with either of the points,
current coming from terminal to pillar P, by wire p², then to indicating
hand Q by g on to either of points and back through either of the arms U, V,
on to tube T, to studs by means of dial S, then through wire 2 to terminal st
and back to battery not shewn.
The operation of my invention is as follows:-Let the instrument as herein-
before described be placed in a room or other place of 60° F., and the temperature
thereof must not go below 40° F. or exceed 100° F. Now the slightest change
of temperature in such room or other place will be indicated by the pointer Q,
on the indicator face or dial S, and should the change he so great as to cause
the pointer Q to reach the limits of 40° F. or 100° F., it will come in contact
with either of the points or 3, and thereby complete the circuit of an electrical
current and cause an alarm to be given by means of the bell connected thereto.
When such an instrument as herein described has been fitted up and the
govenor contained therein has acquired the temperature of the place where it
is to be brought into use, the pointer Q, can be set if necessary, by means of
the adjusting screw Y to the correct degree of temperature marked on the dial S,
through the medium of an ordinary thermometer.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1st. The means by which an alarm can be obtained at any two degrees of
temperature, consisting of the adjustable arms U, V, and parts connected there-
with, constructed, mounted, and operated substantially as herein described and
shewn by Figs. 2, 3, and 5 of the accompanying drawings.
2nd. The means for adjusting the pointer Q to any predetermined temperature,
consisting of the milled headed screw Y, projections y' and % with check nuts z
constructed, mounted and operated as described and shewn by Figs. 2, 3 and 4
of the appended drawings.
3rd. The use of one, three or four compound strips of dissimilar contracting
and expanding metals as described.
4th. The improved means for giving alarms: consisting of the govenor E, F.
binding strip G, projections H, O. links J. N. and oscillating rod K, connected
together by pins, h, j, k, n, and supported in pivot hearings as at p, between
cast iron piece B, and brackets D. M, R, by pillars C. L. P; the projection y on
the latter, and pointer Q with its boss : indicator face Smarked as shewn, with
slot W, and adjustable arms U, V, with fittings, attached to the back thereof:
adjusting screw Y with fittings. together with the frame or casing A. X, in which
the whole is mounted, protected by glass face W and ribbon Z, and fitted
with electrical connections s. 1, 2, 72, constructed. connected, combined and
operated substantially as herein described and shown by the appended sheet of
drawings.