A New or improved Apparatus for Indicating the Heat of Ovens,
Year: 1894

page_text: Date of Application, 19th July, 1894
Complete Specification Left, 11th Oct., 1894-4ccepted, 17th Nov., 1894
PROVISIONAL SPECIFICATION.
A New or improved Apparatus for Indicating the Heat of Ovens,
I, HENRY HARPER WOOD, of Chapeltown, near Sheffield, in the County of
York, do hereby declare the nature of this invention to be as follows :-
My present invention relates to an improved apparatus by which the heat of
ovens is indicated.
It consists of a box or case preferably of cast iron, the open front of which is
closed by a separate cover or front screwed upon it. Into the top of the case is
screwed or otherwise firmly fixed the upper end of a rod or bar, preferably of
brass, the lower end of which, after passing freely through a guide fixed or formed
upon the inside of the case, rests upon a lever turning upon a screw or pivot in
the back of the case. The outer end of this lever is provided with a curved
toothed rack gearing with a toothed pinion the axis of which turns in bearings in
the case, and the lower end of the brass rod already described rests upon the upper
side of the lever at a point near the pivot upon which the latter turns, so that a
very slight movement downward of the rod causes the toothed pinion to move
through a sufficient part of a revolution.
Upon the toothed pinion fixed or formed a weighted lever, to the outer end
of which is pivotted a connecting rod the upper end of which is cranked and
turned outward so that it works and is guided in a vertical slot in the front of the
case, through which the end of the connecting rod projects and is provided with
an index hand or pointer which points to indications upon the sides of the slot.
The lower end of the case is open.
The action of the apparatus is as follows:-
The case being fixed vertically in a convenient position in the oven, the weighted
lever draws down the connecting rod and index hand, the toothed pinion at the
same time raising the lever upon which the lower end of the brass rod rests and
holding it in contact with the latter.
In this position the index hand points to an indication "cold," or zero. When
the oven is heated, the brass rod expands, forcing down the lever upon which it
rests, and raising the connecting rod and index hand to a position dependent upon
the degree of heat, the several positions being pointed out by indications, for
instance, 325° roasting; 350° baking; 375° to 400° pastry, above which may be
placed the words "too hot."
The observer can therefore notice and regulate the heat to exactly the
temperature appropriate to the character of the cooking which is being done.
When the oven cools and the brass rod contracts the weighted lever brings back
the index hand to zero or "cold."
The details of my improved apparatus may be varied more or less, according to
the circumstances in which it is to be used, and the particular purposes to, which it
is to be applied, and by its use, great accuracy and uniformity can be obtained, i
in
the heat required for the different operations with great. benefit to the results
obtained.
It is very simple, durable, inexpensive, and not liable to get out of order, and it
may be applied to ovens or hot chambers of all kinds.
Dated this 18th day of July 1894.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.

page_text: A NEW of pipparatus
I, HENRY HARPER WOOD, of Chapeltown, near Sheffield, in the County of
York, 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, and accompanying drawing, that is to say :—
My present invention relates to an improved, apparatus by which the heat of
ovens is indicated.
The accompanying drawing is in illustration of my invention, Figure 1 being a
vertical section, Figure 2 a front view, Figure 3 a transverse vertical section; and
Figure 4 a horizontal section.
The improved apparatus consists of a box or case a preferably of cast iron, the
open frout of which is closed by a separate cover or front b screwed upon it.
Into the top of the case is screwed or otherwise firmly fixed the upper end of a
rod or bar c, preferably of brass, the lower end of which, after passing freely
through a guide d fixed or formed upon the inside of the case, rests upon a lever e
The outer end of this
turning upon a screw or pivot f in the back of the case.
lever e is provided with a curved toothed rack 9 gearing with a toothed pinion h,
the axis of which turns iu bearings in the front and back of the case, and the lower
end of the brass rod c already described rests upon the upper side of the lever e
at a point near the pivot upon which the latter turns, so that a very slight
movement downward of the lower end of the rod causes the toothed pinion h to
move through a sufficient part of a revolution.
Upon the toothed pinion h is fixed or formed a weighted lever i, to the outer
end of which is pivotted a connecting rod k the upper end of which is cranked
and turned outward so that it works and is guided in a vertical slot in the front of
the case a, through which the end of the connecting rod k projects and is provided
with an index hand or pointer m, which points to indications upon the sides of the
Blot l.
The lower end of the case a is open.
The action of the apparatus is as follows:-
The case a being fixed vertically in a convenient position in the oven, the
weighted lever draws down the connecting rod k and index hand m, the toothed
pinion at the same time raising the lever e upon which the lower end of the brass
rod c rests, and holding it in contact with the latter.
In this position the index band points to an indication "cold," or "zero," as
shewn. When the oven is heated, the brass rod e expands, forcing down the
lever e upon which it rests, and raising, (by means of the toothed segment g and
pinion h,) the connecting rod k and index hand m to a position dependent upon
the degree of heat, the several positions being pointed out by indications, for
instance, (as shewn in the drawing), 325° roasting; 350° baking; 375° to
400° pastry; above which may be placed the words "too hot."
The observer can therefore notice and regulate the heat to exactly the temperature
When the oven
appropriate to the character of the cooking which is being done.
cools, and the brass rod e contracts the weighted lever i brings back the index
hand m to "zero or "cold."
35
The details of my improved apparatus may be varied more or less according to
the circumstances in which it is to be used, and the particular purposes to which
it is to be applied, and by its use, great accuracy and uniformity can be obtained
in the heat required for the different operations, with great benefit to the results
obtained.
.
It is very simple, durable, inexpensive, and not liable to get out of order, and it
may be applied to ovens or hot chambers of all kinds.

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:
A heat indicator for ovens, consisting of a case a, rod c, fixed at one end and
having its other end in contact with a lever conuected with an index hand m in
such manner that the expansion of the rod c by heat causes the index hand to
point out the degree of heat attained, substantially as described and illustrated.
Dated this 8th day of October 1894.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.