IMPROVEMENTS IN OR CON- NECTED WITH THE CONSTRUCTION OF CERTAIN PARTS OF BAKERS OR BAKING OVENS
Year: 1883

page_text: LETTERS PATENT to Frederick Smith of 23 York Street York Road Lambeth
in the County of Surrey for an Invention of "IMPROVEMENTS IN OR CON-
NECTED WITH THE CONSTRUCTION OF CERTAIN PARTS OF BAKERS OR BAKING
OVENS "
PROVISIONAL SPECIFICATION left by the said Frederick Smith at the
Office of the Commissioners of Patents on the 13th March 1883.
"
FREDERICK SMITH of 23 York Street, York Road Lambeth in the County of
Surrey IMPROVEMENTS IN OR CONNECTED WITH THE CONSTRUCTION OF CERTAIN
PARTS OF BAKERS OR BAKING OVENS
"
The objects of my Invention are to save fuel by retaining more perfectly the top
heat of the oven, to afford the baker a better opportunity of producing his articles
in greater perfection; to give him increased facilities for working the oven, to
conduct the heat and steam more perfectly into the ordinary flue made for that
purpose when the oven door is opened which prevents the operative from breathing
a super heated atmosphere, and making the bake-house, as also the dwelling house,
if it is attached to the bakery as is frequently the case, more healthy than hereto-
fore. I also afford increased facilities in the same space for working the oven
(with a short peel) by making the side jambs leading to the oven mouth of a
circular form as hereafter more fully described and I also give the baker more room
for his head by making the top plate of a circular form instead of a flat or inclined
surface as at present in use which allows some portions of heated air to escape
without its necessarily being inhaled by the operative.
"
I also form the "search or fire lining at the head and sides of the interior of
the oven of a somewhat different shape as hereafter described which reduces the
cubical contents of oven and is calculated to increase its strength.
I construct the oven door in a different way to that heretofore existing either as
regards the door hung on hinges at side of frame (now in general use) or the
French imported port-cullis door worked by chains or quadrants.
According to my Invention I hang or fix or suspend the door at the top of the
frame on a fulcrum which will enable it to partly revolve for the purpose of
working the oven and which fulcrum, or rest or support is or forms a portion of the
top of the frame or may be made independent of it. Attached to and immediately
above the door and at each side, or on one side only, are counter balance weights
or a weight any shape or form to properly poise the door in any given position
required. I also make the door of an even thickness throughout or thicker in .

page_text: some cases at the upper part and in other cases thicker at the lower part to more
perfectly obtain the poising of door in any particular position. The counter-
balance weight or weights I fix at the side and at the top of the door and in such
position that when the door is opened the heat escaping from the oven does not
necessarily impinge or beat against the same. To the counter-balance weights I
attach a handle for opening the door made of iron or other metal, or it may be
mnade partly or wholly of wood or other non-conducting substance. The door may
be made of any convenient shape and size and the frame is made to correspond
with the shape of the door to make it steam-tight and can also be made of an extra
width in places and at each side where necessary to allow the gas to be reflected
by means of suitable reflectors into the oven from the outside. In the above cases
the door may be constructed so as to cover the extra size or width and height of
opening or openings. Attached to the frame the opening of which leads into the
oven (and which opening I propose to increase in depth to prevent the door from
striking goods that are baking), I fasten or fix to the said frame in the ordinary
way the side jambs which I prefer to make of circular form as before mentioned
which circular form permits greater facilities for working the oven with short peel
or they may be made in any other suitable form. Immediately above the oven
door I form in the circular top plate before named an opening of sufficient size to
carry off say the steam and heat during the time the door is necessarily open, this
circular plate continues upwards and forwards from the top of frame by mouth of
oven towards underside of chimney bar in general use. In some cases I make the
oven doors before described with an opening or openings in the same for the
purpose of inserting a small frame, or by any other convenient means, properly
prepared glass in order to enable the baker to see into the oven while the door is
only partly open, in order to still further enable him to keep the top heat and
steam from escaping. The glass can be removed for cleaning and replaced with
iron during the time the oven is being beated. The door can be kept fast when
required either by a small latch or latches on same and catch or catches on frames
or by a strut or struts, wedge or wedges, spring or springs. The door can be made
to open either inwards or outwards and in addition to or without the ordinary rest
on frame can be worked with an eccentric which shall have the effect of lifting the
door at the same time that it revolves and can be made to advance itself forwards
leaving a space between top of door and frame to allow steam to escape into flue.
In some cases I advance the bearing or fulcrum beyond the face line of lower
portion of frame to prevent the door advancing so far into the oven. The door is
so constructed as to be easily removed for repair or renewal. The portion of top
of door or horns which rests on fulcrum is in some cases employed for turning the
gas on and partly off as the oven door is opened or closed to afford light for
illuminating interior of oven as also for advancing or retiring the gas. I embellish
the ironwork before named in the usual way. By this construction of door which
opens from the bottom first I retain the top heat in oven as also more perfectly
retain the steam in same thereby assisting very materially to fix the dextrine on
the rolls while in the ordinary batch of bread it would prevent undue crusting at
the top at further end of oven while dough is being set nearer the oven door. It
is also superior to any French port-cullis door for ovens because it can be operated
much more easily and is not so liable to get out of order.
My invention further relates to the construction of the sides and head of the
interior of oven and in place of the present vertical "search" or fire lining or brick
I make the lower portion only vertical and the upper part of a segmental form
also in fire material in order to avoid the weakness of the mortar courses, to give
greater strength to the crown of oven and to afford the bricklayer a truer guide for
the shape of the crown. The above can be made of varying lengths and thicknesses
as required to follow one another around the oven.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frederick Smith in the Great Seal Patent Office on the
13th September 1883.
FREDERICK SMITH of 23 York Street, York Road Lambeth in the County of
Surrey "IMPROVEMENTS IN OR CONNECTED WITH THE CONSTRUCTION OF CERTAIN
PARTS OF BAKERS' OR BAKING OVENS
33
The objects of my invention are to save fuel by retaining more perfectly the
top heat of the oven, to afford the baker a better opportunity of producing his
articles in greater perfection, to give him increased facilities for working the oven,
and to conduct the heat and steam more perfectly into the ordinary flue made for
that purpose when the oven door is opened, which prevents the operative from
breathing a superheated atmosphere, thereby making the bakehouse, as also the
dwellinghouse, if it is attached to the bakery (as is frequently the case) more
healthy than heretofore. I also afford increased facilities in the same space for
working the oven (with a short peel) by making the side jambs leading to the
oven mouth of a circular form as hereafter more fully described; and I also give
the baker more room for his head by making the top plate of a circular form,
instead of a flat, or inclined surface as at present in use, which allows the residue
(if any) of heated air to escape without its necessarily being inhaled by the
operative.
I also form the "search" or fire lining at the head and sides of the interior of
the oven of a somewhat different shape as hereafter described which reduces the
cubical contents of oven and is calculated to increase its strength and cleanliness.
I construct the oven door in a different way to that heretofore existing, either
as regards the door hung on hinges at side of frame (now in general use) or the
French imported portcullis door worked by chains or quadrants.
And in order that this my invention may be fully understood I will now proceed
to describe the same with reference to the accompanying drawings of which
Figure 1 is a front elevation, Figure 2 a horizontal section on line A B of Figure 1,
Figure 3 vertical longitudinal section, Figure 4 vertical transverse section, and
Figure 5 is a front elevation of the oven door drawn on a larger scale to the
previous figures; Figure 6 a vertical transverse section of same, and Figure 7 a
vertical transverse section of the oven door frame taken about CD of Figure 5
but drawn on a larger scale than that figure. Figure 8 shows a full size sectional
elevation of the sliding gas branch or fitting which as shown in this example may
be operated by hand; Figure 9 a cross section through C D of Figure 8; Figure 10
a sectional end view and Figure 11 a plan of burner end of gas branch.
According to my invention I hang, or fix, or suspend the door A at the top of
the frame B on a fulcrum which will enable it to partly revolve for the purpose of
working the oven and which fulcrum, or rest or support, is, or forms a portion of
the top of the frame or may be made independent of it. The fulcrum pins A¹ see
Figure 5 rest in slots and have collars A2 inside for making joint. Attached to
and immediately above the door A and at each side (or on one side only) are
counterbalance weights C, or a weight of any shape or form to properly poise the
door in any given position required. The curved upper edge of the door A in the
normal position abuts against a rib or stop B' on the stock or door frame and thus
the door A is prevented from swinging outward. The door D is similarly
prevented from swinging outward by the stops or lips Bs. I also make the door
of an even thickness throughout or thicker in some cases at the upper part as
shown at Figure 6, and in other cases thicker at the lower part to more perfectly.

page_text: obtain the poising of door in any particular position. The counterbalance weight
or weights C I fix for example as shewn on to the fulcrum pin A' at the side at
the top of the door and in such position that when the door is opened into the
position shown in dotted lines in Figure 6 the heat escaping from the oven does
not necessarily impinge or beat against the same but escapes in an upward
direction as will be presently described.
To the counterbalance weights C I attach a handle C₁ for opening the door.
This handle is made of iron, or other metal covered with leather, or it may be
made partly or wholly of wood or other nonconducting substance. The door A
may be made of any convenient shape and size and the frame B is made to
correspond with the shape of the door to make it steam tight; the frame B can
also be made of an extra width in places I may thus for instance form the frame B
on one side or on both sides of an extra width below forming a chamber B¹. And
I provide a gas-burner in front of this chamber B' to allow the gas to be reflected
by means of suitable reflectors into the oven from the outside. D is an outer door
made to cover the lower part of the opening through the door frame B, and E is a
frame or plate covering the upper part of said opening and which will be described
further on. Attached to the frame B the opening of which leads into the oven
(and which opening I increase in depth forming a passage as shown in Figure 2
for the door A to swing in and preventing the door from striking the goods that
are baking) I fasten or fix to the said frame B in the ordinary way, the side
jambs F which I prefer to make of circular form as before mentioned and as clearly
shown in Figure 2, which circular form permits greater facilities for working the
oven with a short peel. Immediately above the oven door A I form, in the
circular top plate G an opening G' best seen at Figure 6 of sufficient size to carry
off the steam and heat in the ordinary way during the time the door is necessarily
open this circular plate continues upwards and forwards from the top of frame B
at mouth of oven towards underside of the ordinary chimney bar H.
In some cases I make or provide the oven doors before described with an
opening or openings in or at the same such as the opening above the dwarf door D
for the purpose of inserting a small frame such as the aforesaid plate or frame E
fitted with a properly prepared glass piece or pieces E¹ in order to enable the
baker to see into the oven while the door A is only partly open, in order to still
further enable him to keep the top heat and steam from escaping. The glass E¹ or
the frame E can be removed for cleaning and replaced with iron during the time
the oven is being heated. E2 E2 are openings in the frame E; these are covered
by the valves D' which are fixed to the dwarf door D. The latter is used
especially for baking Vienna rolls or where the presence of steam or top heat is
particularly advantageous. When the dwarf door D is raised into the position
shown in dotted lines in Figure 6 the valves D₁ are also opened and permit some
steam to escape immediately into the flue by the aperture G₁ Figure 6 instead of,
as it otherwise would rushing from under the dwarf door D and passing in front
of the outside of the glass pane E' and causing it to be dimmed.
There is a space between the main door A and the other working parts just
described in order to keep them cool when the main door A is necessarily closed
for heating the oven. In some cases I advance the bearing or fulcrum beyond the
face line of lower portion of frame B to prevent the door from advancing so far
into the oven. The doors A and D are so constructed as to be easily removed for
repair or replacement. The door spindle or pins A³ or portions of top of door or
horns which rest on the fulcrum are in some cases employed for turning the gas on
and partly off, as the oven door is opened or closed, to afford light for illuminating
interior of oven and also for advancing or retiring the gas branch into or from the
oven automatically by the opening or closing of the oven door A. For this
purpose I fix a lever L shown in detail at Figure 7 to the counterweight C. or
fulcrum spindle and connect the lower end of that lever by pin and slot to the
sliding gas tube M. best seen at Figure 7; or a gas tube of a similar construction
but actuated by hand separately from the door .A. may be used as shown to a

page_text: the oven.
larger scale at Figures 8, 9, 10 and 11. The tube M can slide in the outer tube N
being guided therein by feather and groove M' and is formed with a small hole
at M² by which it is supplied with gas from the elbow or other fitting O. The
tube M is closed in front beyond where it passes through a stuffing box. The
other end of the tube M is provided with a gas burner M³ and its end is closed by
means of a bracket M* which fits a hole leading to the aforesaid chamber B¹ and
stops up the said hole in the side part of the frame B leading to the interior of
When the door A is opened the lever L pushes the gas tube M forward
whereby the bracket or piece M, which filled the corresponding hole in the
frame B, is pushed into the interior of the oven. At the same time the gas supply
hole M (which in the former or normal position was so nearly covered by the
inner part of the stuffing box as only to permit a small jet to burn as shewn in
dotted lines on the left side of Figure 8) will now be fully opened and thus
produce a large jet or flame in the interior of the oven as shown in dotted lines in
fig. 7. Or the tube M may, if desired be disconnected from the lever Land
worked by hand as shewn at Figure S.
"
The "search or inner lining of the oven is as shown at Figures 3 and 4 at the
head and sides of the oven formed of lumps S of firebrick which are straight and
vertical at the lower part and curved inwardly at the upper part where the arch
bricks rest on them. I prefer to use a lump of a curved form in plan also in the
two back corners of the oven as shown at Figure 2.
Having now described the nature of my said invention and in what manner
the same is to be performed I declare that I claim.
First Constructing bakers ovens with swinging counterbalanced doors hung
from the top of a door frame which is made of such depth that the door when
open will not strike the goods that are baking, for the purpose of keeping in part
of the top beat and of the steam when the door is open as required for working
the oven, substantially as set forth.
Second: Constructing baking ovens with swinging counterbalanced inner or
main door hung from the top, in combination with a deep door frame and with an
outer upper glazed sight frame with valve apertures, and lower swinging
counterbalanced outer dwarf door with corresponding valves substantially as set
forth.
Third Forming the jambs of baking ovens with concave parts as described for
the purpose of affording greater facility for working the oven with a short peel,
also forming the top plate curved for the purpose of affording more room for the
bakers head, substantially as set forth.
Fourth-Forming the head, sides and corners of the inner firebrick lining or
"search" of baking ovens of a partly vertical and partly inwardly inclined curved
form substantially as and for the purposes set forth.
Fifth The combination of parts forming the improved appliance for lighting
the interior of the oven, substantially as set forth.
In witness whereof I the said Frederick Smith have hereunto set my hand
and seal this Tenth day of September One thousand eight hundred and eighty
three.