Improvements in and connected with Oven Doors.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in and connected with Oven Doors.
1
I, DAVID ESPLIN THOMSON, of Slateford Road, in the County of the City of
Edinburgh, North Britain, Engineer, do hereby declare the nature of this inven-
tion to be as follows:-
This invention relates to a method of making oven doors for drawplate and
other ovens when built in two decks, and has for its object to simplify the
mechanism for the opening of these doors where decker ovens are used.
The invention consists in a door made to cover the openings and arranged to
slide in either direction, up or down. The door is balanced by a chain passing
over wheels overhead and may be easily operated. When the top oven is open the
door is slid down, when both ovens are closed the door is placed in medium
position, when the lower oven is opened the door is raised.
The door is held in position and closed by means of eccentric movements.
Dated this 16th day of September 1898.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Patent Agents.
I, DAVID ESPLIN THOMSON, of Slateford Road, in the County of the City of
Edinburgh, North Britain, Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement: -
This invention is designed to simplify and facilitate the opening and closing of
ovens when such are built one on the top of the other.
It is fully described as applied to draw-plate ovens with reference to the
accompanying drawings in which,
Figure 1 is a front elevation
Figure 2 part longitudinal section of ovens,
Figure 3 plan and section of roller bearing R to an enlarged scale.
I construct the door A of oven in one, or in several pieces of metal fastened
together in such manner as to leave space B, Figure 2 between the front and back,
this space being filled with asbestos or other non-conducting material to prevent
the radiation of heat from the oven. The door is of size sufficient to close both
openings CC into oven chambers D, 1), at the same time, as shown in Figure 2.
The door is balanced by counterweights E₁ E shown dotted at back of metal

page_text: 2
2
framework in Figure 1.
The connection between door and its counterweights I
make by means of pitch chains F, F, at each side of door Figure 1, these pitch
chains pass over sprocket wheels G, G₂ fixed on the spindle H. This spindle being
revolved by means of either of the handwheels J, J, raises or lowers the door A.
K, K, are the draw plates in their respective oven chambers D, D. Figure 2
shows both oven chambers closed by the one door A. M, M, are handles with
eccentrics on their ends and fastened to spindle N₁. M, M, are similar handles on
spindle N. With door closing both ovens as on Figures 1 and 2, these eccentrics
by means of the handles are brought to act against the guides 0, 0, Figure 1 and
thereby force the inside face of door, which is a planed surface, against the planed
face of the metal framework of oven P, P, P, Figure 2 thereby preventing leakage
of heat from either oven.
If it is required to open the top oven D₁, these eccentrics are all released by
one handle on each of the spindles N, N,, and on one of the handwheels, either J₁
or J, being turned, the door is lowered until its top edge is at the level of the
bottom of opening C, into oven chamber D₁, when the drawplate K, can be with-
drawn, unloaded and recharged; during which time the bottom oven remains
closed by the door, the eccentrics having been brought into action, so as to keep
door close up to the bottom oven front.
If it is desired to open bottom oven the door is raised till its bottom edge is level
with the top of opening C₂ into oven chamber D₂, when the drawplate K, can be
withdrawn. During the time drawplate is out of oven chamber D₂, the upper
oven D, is sealed by the door being acted on by the eccentrics.
I thus get rid of the complications and space occupied by having a separate door
for each oven, requiring duplicate chains, spindles, sprocket wheels, balance
weights, &c., &c., such as has been in general use with such ovens till now.
To make the large door easy to move I eliminate friction to a very large extent
by supporting the spindle H in the roller or ball bearings R, R, shown in plan
and elevation to an enlarged scale in Figure 3. I am thus enabled to raise or
lower the large door A quite as easily, if not more easily, than it would be possible
to raise or lower a door of a size sufficient to close only one oven mouth, when such
door is actuated by spindle carried in ordinary bearings.
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:
The arrangement by which one door is made to serve for the opening and closing
of two ovens when built one on the top of the other, substantially as described.
Dated this 17th day of June 1899.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Patent Agents.