Improvements in and relating to Bakers' and like Ovens.
Year: 1898

page_text: Date of Application, 28th Mar., 1898-Accepted, 4th June, 1898
COMPLETE SPECIFICATION.
Improvements in and relating to Bakers' and like Ovens.
I, JOHN KERR JOHNSTON, of Churchtown Park, Dundrum, in the County of
Dublin, Ireland, Miller and Baker, 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:-
This invention relates to bakers' and like ovens which during the operations of
charging and discharging are lighted by internally arranged gas jets.
In ovens of this kind there is frequently considerable waste of gas owing to the
attendant leaving the jets alight after the oven door has been closed. Moreover
in cases where much steam is produced in the baking, considerable danger and
damage frequently arise by reason of the flame being extinguished and the
unconsumed gas escaping into the oven.
Now the object of my invention is to overcome these objections by providing
convenient means whereby the closing of the oven door automatically stops the
supply of gas to the lighting jets. The arrangement is preferably such however
that the converse operation of opening the oven door does not again turn on the
gas, this latter operation requiring to be effected by the attendant.
For the purposes of my invention the oven door or any suitable attachment
thereon may be caused to act directly or indirectly on the lever or handle for
operating the tap or cock controlling the supply of gas to the jets.
In some cases the tap for turning the gas on and off, may be provided with a
projecting spring arm or blade adapted to be engaged by a finger or projection
secured to the door, so as to operate the cock in the manner referred to.
The brickwork or setting of the oven may have built into it suitable iron or
other piping for the gas pipes to pass through.
If the oven be one intended for goods that bake without producing much steam,
a cock may be employed having a bye-pass to avoid the necessity of re-lighting the
gas when the oven door is opened.
In order that my invention may be clearly understood and readily carried into
effect I will proceed to describe the same fully by aid of the accompanying
diagrammatic drawings in which:-
Figure 1 illustrates an arrangement suitable for an oven in which the door
is flush or thereabouts with the oven front.
Figure 2 is a detail view of a tap or cock such as I employ.
Figures 3, 3, 4 and 4* illustrate modifications which may be used in cases
where the oven door is fitted in an inwardly projecting frame.
Referring more particularly to Figures 1 and 2:-
a is the door of the oven and b is the tap for regulating the supply of gas to
the jet or jets for illuminating the inside of the oven. The door is provided with a
projection or finger a' for acting on a spring-arm 61 secured in this case to the
thumb piece of the gas tap, at an angle of 45° or thereabouts as shown more clearly
in Figure 2 and serving the purpose of the lever or handle above mentioned.
The movements of the tap are limited by a pin 62 in its plug and by stops or

page_text: shoulders on its outer casing or shell in the ordinary way, but the stops are so
arranged that the tap can only be turned through ninety degrees, that is to say
from the position in which it is fully open to the position in which it is quite
closed.
In other respects the tap 6 is similar to an ordinary gas tap.
c is a length of iron piping let into the wall of the oven, d is a gas pipe
extending through the piping c to the jet or jets inside the oven, and e is a
union-coupling of. the ordinary kind whereby the pipe d is connected to the
tap b.
The purpose of this arrangement is to enable the pipe d to be readily dis-
connected from the tap and withdrawn from the oven, so that the burner can be
cleaned or renewed without the necessity for anyone going inside the oven.
It will be seen from Figure 2 that when the oven door is closed the finger a¹
strikes the spring arm 61 and turns it from the position shown by the dotted lines,
into that shown by the full lines, thus shutting off the gas inside the oven.
The opening of the door does not however affect the gas tap, as the finger a¹
simply retires from the spring arm b. Consequently the tap must be turned on
by hand to permit of the gas being relighted.
In the arrangement shown in Figure 3 the door a is fitted in a receding frame aª
and the motion is transmitted to the spring arm 1 of the tap through the medium
of a suitable slide f mounted in brackets or supports f¹ secured to the door frame.
This slide has a finger or projection f at each end as in Figure 3. One finger
is engaged by the finger a¹ on the door as the latter closes, and the other finger
engages the spring arm 6' on the gas tap.
In the arrangement shown in Figure 4, the slide is replaced by an arrangement
of levers g g which transmit the motion through a shaft g2 from a finger or pro-
jection a¹ on the oven door to the tap or cock b which latter is substantially similar
to that previously described. The end of the lever g is curved slightly as shown
in the detail view Figure 4, so that when the finger a¹ strikes it, it is turned up into
the position shown in dotted lines and at the same time partially rotates the
shaft g, thus causing the lever g¹ to act on the spring arm b¹ and close the tap.
In this latter instance the tap is so arranged that the spring arm 6" is horizontal,
but obviously the tap may be arranged vertically as in Figures 1 and 2 in which
case the lever g¹ would be provided with a lateral projection or finger adapted to
act on the tap after the manner of the finger a¹ shown in the said figures.
The foregoing arrangements are given only as examples of the manner in which
my invention may be applied, and it should be understood that the said invention
is not confined to the ovens having hinged doors as it may be readily applied in an
analogous manner to sliding doors, or to doors or closing sheets which are arranged
to be lifted off or removed bodily from the opening or mouth of the oven.
The fingers a¹ and fx above mentioned as well as other parts such as the lower
end of the lever gl (Figure 4) may be provided with friction rollers if desired.
Moreover instead of a spring arm b on the gas tap, I may employ an ordinary
lever or the like, or I may operate the tap by means of toothed gearing or by chains
or wire-cords or otherwise.
In cases where the oven is intended for baking goods which do not give off
much steam, the cock outside the oven may be provided with a bye-pass to enable
it to be turned up without the necessity for re-lighting. In those cases where
much steam results from the baking operation I prefer however to use burners
which are turned out completely, as there is then no chance of the gas flame being
extinguished in such a way that the gas is left escaping inside the oven.
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:-
1. An oven lighted internally by gas, the supply of which is controlled by a tan i

page_text: so arranged that it is closed by the act of closing the oven door, substantially as
described.
2. The construction of the oven door with a finger or projection adapted to act
either directly or indirectly upon the gas tap, substantially as described with
reference to the accompanying drawings for the purpose specified.
3. The gas tap provided with the spring arm substantially as described and for
the purposes specified.
1
1000
HASELTINE, LAKE &. Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.