Improvements in Thermostats.
Year: 1889

page_text: Date of Application, 8th Oct., 1889-Accepted, 23rd Nov., 1889
COMPLETE SPECIFICATION.
Improvements in Thermostats.
I, HARVEY CORTLAND, of the City of Toronto, in the Province of Ontario, in the
Dominion of Canada, Gentleman, do hereby declare the nature of my invention
for IMPROVEMENTS IN THERMOSTATS, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My invention has for its object to construct a thermostat which shall be sensitive,
and adapted for open or closed electric circuits and to protect certain parts from
corrosion.
My invention consists of a thermostat having an annular metallic case surrounding
a concavo-convex hard rubber diaphragm, A metallic flexible tongue insulated from
the case and extending diametrically across the same, and provided with an adjusting
screw bearing on the centre of the concavity of the diaphragm, binding posts
secured to the case, one post electrically connected to the tongue and insulated from
the case, and an adjustable contact post screwing through the case at the free end
of the tongue, so that the diaphragm contracting and expanding by the temperature,
will cause increased or diminished concavity, whereby the contact of the tongue
with the contact post is closed when the diaphragm is expanded, and by contraction
cause separation of the tongue from the contact post.
Also, in partly enclosing said thermostat in a shell to prevent corrosion of the
sensitive or operating parts.
Also, in the employment, in said thermostat, of a contact post baving an insulated
portion, whereby the tongue when placed in frictional connection with the side of
the post will make contact and break circuit according to the tongue rising or falling
above or below the insulated portion of the post by the expansion and contraction of
the diaphragm, as before described.
Referring to the accompanying drawings,
Figure 1, is an elevation of the inner face of my improved thermostat, omitting the
outside protecting shell.
Figure 2, is an elevation of the opposite face of the thermostat, inserted in said
shell.
Figure 3, is a section of the same on line a Figure 2; and Figure 4, is a
partial section showing the tongue edgewise in contact with the insulated side of
the post.
1, is an annular metallic case preferably composed of a rim section shown in
Figure 1, and a front section shown in Figure 2, the latter having an outwardly
dished disc-portion a,
and a central aperture b, to admit the atmosphere, and both
sections are secured together through the rim by screws 2, 3, which pass into the
foot of binding posts 4, 5, respectively. The screw 2, is insulated from said case
and the other is not. Both binding posts are provided with a slot 6, and a screw 7,
to hold the circuit wires 8, 9, at the respective electric poles of the thermostat.
10, is a concavo-convex diaphragm of hard rubber held by the edge between the
sections of case 1, by compression-of said sections by the screws 2, 3.
11, is a spring tongue, secured to an insulator 12, by screws 13, and said insulator
is secured to the case by screws 14. One end of tongue 11, is connected to the
insulated screw 2, by an insulated wire 15, and said screw connects with the binding
post 4, as before described.
The spring tongue 11, at the middle, is provided with an adjusting screw 16 or
bearing, which bears on the centre of the concavity of the diaphragm 10, and the free
end of the tongue is vertical with an adjustable contact post 17, which screws through
the rim or case 1, so that when the diaphragm is expanded, the concavity of the

page_text: diaphragm is deepened, and allows the free end of the tongue to have contact with
post 17, and permits the electric current to pass through the line wire 9, thus
completing the circuit when an open circuit is used, said circuit including a suitable
alarm to give notice of a higher temperature than that to which the thermostat is
adjusted.
18, is an exterior shell in which the thermostat is screwed, the elevation shown
in Figure 1, facing the back of the shell inwardly, as in Figure 3, said shell then
protecting such parts from corrosion by dampness.
The contact post or screw 17, if desired, may have an insulated band c, and the
tongue 11, may have constant frictional contact with the side of the post, whereby
the tongue will break the circuit when in contact with the insulated portion or band e,
of the post, as shown in Figure 4.
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. The combination with the annular case 1, of the concavo-convex diaphragm 10,
provided with a screw 16, to bear on the concavity of the diaphragm at the centre,
connection wire 15, binding post 4, contact post or screw 17, and binding post. 5,
substantially as set forth.
concavo-convex
2. A thermostat, comprising a shell 18, an annular case 1, a
diaphragm 10, spring tongue 11, insulated from the case, and having a bearing 16,
on the centre of the diaphragm, an insulated binding post 2, connected to said tongue
by an insulated wire 15, an adjusting screw or contact post 17, and a binding post 4,
in connection with said case, whereby the free end of the tongue contacts with post 17,
when the diaphragm is expanded by atmospheric influence, to pass the electric current
from one binding post to the other, substantially as set forth.
3. The contact post 17, having an insulated portion c, in combination with a
tongue 11, having frictional connection therewith, as set forth.
Dated this 8th day of October 1889
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Inventor.