CERTAIN IMPROVEMENTS APPLICABLE TO BAKERS' OVENS
Year: 1856

page_text: LETTERS PATENT to Alexandre Tolhausen, of No. 7, Duke Street, Adelphi,
London, County of Middlesex, Sworn Interpreter at the Imperial Court
of Paris, for the Invention of "CERTAIN IMPROVEMENTS APPLICABLE TO
BAKERS' OVENS."A communication from Hiram Berdan of Flatland ILS
PROVISIONAL SPECIFICATION left by the said Alexandre Tolhausen
at the Office of the Commissioners of Patents, with his Petition, on the
11th March 1856.
I, ALEXANDRE TOLHAUSEN, of No. 7, Duke St., Adelphi, London, County
of Middlesex; Sworn Interpreter at the Imperial Court of Paris, do hereby
declare the nature of the said Invention for "CERTAIN IMPROVEMENTS APPLI-
CABLE TO BAKERS OVENS," being a communication from Hiram Berdan, of
Flatland, U. S., 'to be as follows:
This Invention consists in furnishing an oven with an endless chain of shelves,
which has a continuous ascending & descending motion imparted to it by the
weight of the bread or other substance or substances undergoing the baking
process on the shelves, or by other means, & which is thereby, with the appli-
cation of suitable gearing, caused to give motion to the machinery, by which
doors suitably arranged are opened & closed in proper succession & at proper
intervals, of time to admit into the oven the bread or other substance or sub-
stances, to be baked, & to draw the same from the oven after it or they have

page_text: been baked for a certain sufficient length of time. The bread or other sub-
stance or substances to be baked is or are placed on a series of cars or carriages,
which enter at suitable intervals into a door at the upper part of the oven by
one branch of a suitably arranged railway, & are received on such shelves at
the upper part of the descending side of the chain as are at the time passing
the said door; & as the loaded shelves severally arrive near the lower part of
the oven they are drawn out through another door on to the lower railway, on
which they run to a suitable place to be unloaded; after which they are run on
another branch of the lower railway to a door, by which they are admitted to
such shelves on the lower part of the ascending portion of the chain as are at
the time passing the said door to be carried by the ascent of the said shelves
to a door, at which they are drawn out to a branch of the upper railway, &
after being conveyed to a suitable place for loading again, are again drawn into
the oven through the first-mentioned door opposite the upper part of the
<lescending side of the chain. The velocity of the motion of the chain of shelves
is so regulated, that the time occupied in the descent of the cars from the first-
named door to the second is sufficient for the baking. The Invention almost
entirely dispenses with manual labour in placing the bread or other substance
or substances to be baked in the oven & drawing it therefrom. It economizes
fuel; it effects a reduction of the room necessarily occupied by the bakery; it
enables the baking process to be performed with greater uniformity than in any
oven with the usual appliances; & it makes the operation of the oven con-
tinuous for as long a period as the machinery continues in working order.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexandre Tolhausen in the Great Seal Patent Office on 2
the 8th September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDRE
TOLHAUSEN, of No. 7, Duke Street, Adelphi, London, County of Middlesex,
Sworn Interpreter at the Imperial Court of Paris, send greeting.
WHEREAS Her 'most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of March, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth. year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Alexandre Tolhausen, Her special licence that I, the said Alexandre
Tolhausen, my executors, administrators, and assigns, or such others as I,

page_text: the sand Alexandre 10lhausen, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "CERTAIN IMPROVEMENTS APPLICABLE TO BAKERS' OVENS," a communication
from Hiram Berdan, of Flatland, U. S., upon the condition (amongst others)
that I, the said Alexandre Tolhausen, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Sea! Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alexandre Tolhausen, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This Invention consists in furnishing an oven with an endless chain of
shelves, which has a continuons ascending and descending motion imparted to
it by the weight of the bread or other substance or substances undergoing the
baking process on the shelves, or by any other means, and which is thereby,
with the application of suitable gearing, caused to give motion to the machinery,
by which doors suitably arranged are opened and closed in proper succession
and at proper intervals of time to admit into the oven the bread or other sub-
stance or substances to be baked, and to draw the same from the oven after it
when they have been baked for a certain sufficient length of time. The bread or
other substance or substances to be baked is or are placed on a series of cars or
carriages, which enter at suitable intervals into a door at the upper part of the
oven by one branch of a suitably arranged railway, and are received on such
shelves at the upper part of the descending side of the chain as are at the time
passing the said loor; and as the loaded shelves severally arrive near the lower
part of the oven they are drawn out through another door on to the lower rail-
way, on which they run to a suitable place to be unloaded; after which they
are run on another branch of the lower railway to a door, by which they are
admitted to such shelves on the lower part of the ascending portion of the
chain as are at the time passing the said door to be carried by the ascent of
the said shelves to a door, at which they are drawn out to a branch of the
upper railway, and after being, conveyed to a suitable place for loading, again
are drawn into the oven through the first-mentioned door opposite the upper

page_text: part of the descending side of the chain. The velocity of the motion of the
chain of shelves is so regulated, that the time occupied in the descent of the car's
from the first-named door to the second is sufficient for the baking. The
Invention almost entirely dispenses with manual labour in placing the bread or
other substance or substances to be' baked in the oven and drawing it there-
from. It economizes fuel; it effects a reduction of the room necessarily
occupied by the bakery; it enables the baking process to be performed with
greater uniformity than in any oven with the usual appliances; and it makes
the operation of the oven continuous for as long a period as the machinery
continues in working order.
The Invention is illustrated in the accompanying Drawing, in which Fig. 1
is a sectional elevation of the oven, showing the arrangement of the endless
chain of shelves; Fig. 2 is a horizontal section of the same; Fig. 3 is a front
elevation of the oven, and the machinery for opening the doors and conveying
the cars into and drawing them from the oven; Fig. 4 is a vertical section of
the oven at right angles to Fig. 3, with a side view of the railways and principal
portions of the machinery; Fig. 5 is a horizontal section of the oven with one
of the railways; Fig. 6 is a side view of a switch and its operating mechanism,
by which the cars are directed on the railway as they leave and advance
towards the oven; this switch is also shown in Fig. 5; and Fig. 7 is a 'section
of the chain of shelves taken through the centres of the guide rollers. Similar
letters of reference indicate corresponding parts in the several Figs.
In carrying out this Invention, the oven must be of great height in proportion
to its horizontal area, as compared with the proportions of other ovens, in order
to get as large a number of shelves in the endless chain as is practicable, and
it is proposed generally to make the oven of such a height that the fire place I,
shown in Figs. 1 and 3, being in the basement or on the ground floor. of a
building, the doors A, where the bread or other substance enters will be two
stories above, and the door B, where it comes out after having been baked, on
an intermediate story; the first-named door A and the railway C leading to
it being at a convenient height from the uppermost floor D, and the door B
and the railway E leading from it being at a convenient height from the floor
F, as it is illustrated in Fig. 4, where the two floors are shown in section.
The oven consists of an upright chamber G, of quadrangular or other con-
venient form in its horizontal section, having its bottom composed of a slab or
slabs of soapstone or other refractory substance, as shown at H, Fig. 1, below
which the furnace I is constructed, and having its roof of a construction similar
to that of other ovens, or of any other suitable construction. From the furnace
a suitable number of upright flues a, a, constructed of fire clay tubes or of fire

page_text: brick run right through the oven, which is heated by radiation from the said
flues and from the bottom H. The shelves J, J, consist of open frames
of iron, bolted each at the two ends of its outer side to two opposite links K, K',
of two endless chains K, K, and K', K', which extend nearly from top to
bottom of the oven. The length of the links of these two endless chains
between their connecting pivots b, b, is equal to the distance between the upper
surfaces of the shelves, so that each pair of links, that is to say, one link of one
chain and the opposite corresponding link of the other chain carry one shelf,
thus obtaining the greatest possible length of link, and thus to obtain the
greatest possible degree of stability for the shelves, which are kept always in a
horizontal position, except when passing from one side of the oven to the other,
when they form the radii of an arch, as is shown in Fig. 1, by means of a set
of rollers c, c, applied outside each chain to run in one of two grooved iron
ways L, L', which are built into the front and rear walls of the oven. These
ways have each two upright sides, united by arches at top and bottom, and the
rollers following the course of the said ways support the shelves. The rollers
c, c, are applied to the pivots b, b, of the chains, each of which is extended in
the form of a long spindle through the chains, as shown in Figs. 4 and 7.
Each shelf has a railway d, d, both upon its upper and under sides, to cor-
respond with the railways C and E outside the oven, for the purpose of receiving
the cars M, M, on which the loaves or other articles to be baked are placed.
These cars are constructed with light iron frames, and fire-brick or soapstone
bottoms, in order that when once heated they may retain their heat, and that
but little heat may be lost by radiation when they are run out of the oven, and
they are mounted on low flanged wheels e, e.
In Fig. 3 all the doors of the oven are fully shown, and the outline of the
chain of shelves is shown by two dotted lines e', e', which shows all the doors
to be opposite to the shelves. The same condition as relating to two of the
doors A, A, is shown in Fig. 2. The door A opposite to the upper part of
the right-hand side of the chain, see Fig. 3, is that at which the loaded cars
enter the oven, and the door B opposite to the lower part of the same side of
the chain is that at which they come out after their contents have been baked
sufficiently. The door. B', opposite the lower part of the left-hand side of the
chain, is that at which the cars, enter the oven again after the baked loaves or
other articles have been taken from them, and the door A', opposite the upper
part.of the same side of the chain, being that at which the cars come out again
to be reloaded. The door A' is a little higher than A, and the door 'B' a little
Each of the railways C and E have two branches, the branch
C* of C descending into the door A, and the branch C¹ of the same descending
lower than B.

page_text: from the door A¹; the branch E* of E descending from the door B, and the
branch E' of the same descending into the door B. The grades of these branches
are shown in Fig. 4, where the surfaces of the rails are represented by strong
black lines The several links of the two chains K; K, and K', K', have teeth
in their outer edges, as shown in Figs. 1 and 4, to form endless racks, which
genr
with two pinions f. f, on a shaft g, the said pinions having the same number
of teeth as the several links K, K', so that the shaft g may receive exactly one
complete revolution from every shelf that passes it as the chain derives motion
from the weight of the loaves or other articles on the right hand shelves. This
shaft serves as the driving shaft to the mechanism, by which the doors are
opened in regular succession and at regular intervals, and also to the me-
chanism by which the cars are pushed into and drawn from the oven, and thus
the speed of the movement of the shelves, and the times of effecting the
opening of the doors, and the action of the mechanism for pushing up and
drawing out the cars, all bearing a certain invariable relation to each other;
and the doors being arranged in proper positions relatively to each other, a
a shelf will be caused by the movement of the chain in the direction of
the arrows, shown in Fig. 1, to arrive exactly opposite either door at the time
of its opening, and a car will be run in or out, as may be necessary.
The door A is
lever . The
The doors open by a vertical sliding movement. The mechanism by which
they are opened consists of four wiping rollers h³, h², h, h, attached to armis
on the shaft g, acting respectively upon four levers i, 2, 2, 2, which are hung
on fulcrum pins j. j, j, secured in the front wall of the oven.
hung on a lever k', which is connected by a rod l, with the
door A¹ is hung on a lever k³, which is connected by a rod with the lever i²,
which is behind , and on the same fulcrum, and therefore not separately
distinguished so as to be both visible in Fig. 3, where the other levers are
shown. The door B is hung on a rod from the lever ³, and the door B
is hung on a rod from the lever . The order of succession in which the
doors are opened is as follows, A, A', B, B. The two rollers h², h³, are not
separately distinguished so as to be both visible in Fig. 3, as the latter is
behind the former, attached to the same arm, as shown in Fig. 4. All the
above rollers are in different vertical planes. In Fig. 3 the roller * is repre-
sented in operation upon the lever it, and the door B₁ open. The ends of the
levers,,,, are so formed that the doors are opened quickly, and
allowed to remain open a short time, and afterwards close quickly by their
own weight as the rollers work clear of their respective levers. The cars
are run into the doors A and B₁ by means of dogs m and m' attached
respectively to the upper and lower ends of the lever N, which works on a

page_text: fulcrum pin n, which is intended to be supported in a framing erected on
the floor F. The above framing is not, however, shown in the Drawing, as it
would hide some of the moving parts of the machinery. The cars are drawn
out at the doors B and A by long hooked rods o, o', which are attached
respectively to the lower and upper ends of the lever N, and which enter the
oven to catch the back ends of the cars. The lever N receives a constant
vibrating motion through a connecting rod p from an eccentric wrist
9, which
is attached to a circle plate on a shaft s, which receives a continuous rotary
motion through a pair of bevel wheels t, t', from the shaft g, at a speed of
four to one of the said shaft g, causing, the lever N to make four complete
vibration's back and forth during every revolution of the shaft g. By one of
these vibrations the dog m is caused to push through the open door a car,
which at the time stands in readiness on the inwardly descending branch C*
of the upper railway C, as shown in Fig. 4, where the upper end of the lever
is supposed to be commencing its forward movement. The succeeding revo-
lution of the shafts causes the upper hook o¹ to draw a car through the
open door A', the said car when it comes out of the oven running down the
outwardly descending branch C¹ of the railway C to a suitable point on the
main line C, to be loaded with a fresh batch by an attendant who is in readi.
ness on the upper floor D. The next revolution of the shaft s causes the
lower hook o to draw out a car at the open door B, the said car when it gets
out of the oven running down the outwardly descending branch E* of the
railway E to a suitable point on the main line E, to be unloaded by an
attendant stationed on the lower floor F, or to unload itself by a self-acting
tilting apparatus, which may be provided for the purpose. A fourth revolution
of the shaft s causes the lower dog m¹ to run back into the oven through the
opening door B' an empty car, which has been waiting on the inwardly
descending branch E' of the railway E. The repeated revolutions of the
shaft produce a repetition of the above-described operations. While a
car is waiting on the unwardly descending branch C* of the railway C,
it is held back clear of the door until the opening of the door A takes
place by means of the turned-up end 10 of a lever u, which works on a
fixed fulcrum v, the said turned-up end of the lever being held up by a
weight a at the opposite end of the lever, as shown in Fig. 4; but at the
same time that the said door A is opened by the action of the wiper roller '
on the lever v', the turned-up end of the lever u is pulled down clear of the
car by a rod w, which connects it with the lever i, and the car runs by
gravitation into the oven along the rails d, d, of that shelf which is passing at
that time. In connection with the lever u there is another lever x, which

page_text: works on a fixed fulcrum y, and has attached to it a guiding piece 2, when,
until the turned-up end of the lever u is pulled down, serves as a guide to the
dog m after it has run back off the side of the car on which it slides and over
the outer edge of the same, and thus prevents the dog falling to catch the
outer end of the car during such movements of the lever N as take place after 5
the car has been run into the branch C* of the railway, and before the door
is opened and the turned-up end 10 of the lever pulled down to allow the car
to run in this prevents the dog being operative till the proper time for
running in the car, when the guiding piece z falls and allows the dog to drop
in front of the outer end of the car. An arrangement of levers u', ', the
former with a turned-up end and the latter with a guiding piece ', is used in
connection with the door B' for a similar purpose, the lever u¹ being operated
upon to pull down its turned-up end and the guide piece 21 of the lower dog m
as the door opens by means of a rod w³, see Fig. 3, connecting the lever u¹
with a lever 8, which connects by a rod 9 with the lever . In Fig. 4 the
levers u¹ and a' are shown with the turned-up end 10 of the former, and the
guide and guide piece of the latter drawn down, and the dog ml as having
fallen into an operative position to correspond with the open condition of the
door B, represented in Fig. 3.
The self-acting switches, with which both the railways C and E are provided,
are both substantially like that represented in Figs. 5 and 6, where 11, 11,
represent the switch points, whose connecting bar 12 is connected with one
arm of an elbow lever 13, which works on a fixed fulcrum 14, and whose other
arm connects with a bar 15, arranged longitudinally between the rails, the said
bar 15 being attached to the lower ends of two small upright levers 16, 17,
whose upper ends stand above the rails.
door B down the branch E* strikes the
the direction of "the arrow shown near it,
position shown in dotted outline in Fig. 5.
towards the brauch E the action is directly the reverse. The only difference
between the mechanism of this switch and that belonging to the upper railway
C is that in the latter the descent of the branches being the reverse of the
former, requires the action of the switch to be the reverse.
The car in running out from the
lever 17, and moves the bar 15 in
and thus throws the switch to the
In running from the main line E
The velocity of the movement of the chain of shelves may be governed, if
the descent of the several shelves from
necessary, so that the time occupied
the door A to the door 'B will be just sufficient to complete the baking process,
by means of a pendulum 'escapement of any well-known kind applied in any
convenient manner. This is. not represented, as the mode of applying it will
readily suggest itself to any mechanic of ordinary capacity. A fly wheel may

page_text: also be applied to a shaft, suitably geared from the shaft g or s, for the purpose
of preventing any shocks that may occur to any portion of machinery, and
producing a smooth, regular, and uniform movement.
Having now set forth the nature of the Invention of "Certain Improvements
applicable to Bakers' Ovens," as communicated to me, and explained the
manner of carrying the same into effect, I wish it to be understood that under
the above in part recited Letters Patent I claim,-
1st. Providing an oven with an endless chain of shelves J, J, having
an ascending and descending motion, for the purpose of bringing the shelves
in regular succession opposite to a door at which the bread or other substance
to be baked is to be introduced, and another door at which it is to be with-
drawn, substantially as described.
2nd. The employment of the weight of the bread or other substance being
baked to give a continuous motion to the endless chain of shelves, and make the
said chain serve as the prime mover of machinery for opening and closing
the oven doors at stated intervals; and machinery for charging and discharging
the oven, substantially, as herein set forth.
3rd. The within-described arrangement of railroads and switches, in combina-
tion with the rails d, d, on the shelves of the chain, to run the bread or other
substance or substances in and out of the oven on cars, substantially as
herein set forth.
4th. An arrangement of four doors, which admits of the bread or other
substance to be baked being introduced to the oven and an empty car drawn
from the oven at one end of the chain, and of the baked bread or other sub-
stance being drawn from the oven and an empty car introduced at the
other end of the chain, whereby the empty cars are enabled to be carried to a
suitable place to be filled by one side of the chain, while the cars, carrying the
baking bread, are gradually moving with the opposite side of the chain towards
the place where they are to be discharged, substantially as berein set forth.
5th. The mechanism through which the doors are opened by the rotary
movement of the shaft g, or its equivalent, derived from the movement of the
endless chain of shelves, substantially as herein set forth.
6th. The combination of the two hooks o, o', and two dogs m, m', to
operate substantially as herein set forth, for the purpose of pulling out and
pushing in the cars.
7th. The combination of the levers u, u', and the levers, a, a, for the purpose
of arresting the cars and rendering the dogs inoperative until the entrance
doors of the oven are opened to admit the cars, substantially as herein
described.

page_text: 8th. The general arrangement of the whole of the mechanism, by which the
operations of opening and closing the doors, and introducing and withdrawing
the cars are effected, substantially as herein shown and described.
In witness whereof, I, the said Alexandre Tolhausen, have hereunto set
my
hand and seal, this First day of September, in the year of our
Lord One thousand eight hundred and fifty-six
A. TOLHAUSEN. (L.S.).