Improvements in or connected with Safety or Cut-off Gas Burners.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in or connected with Safety or Cut-off Gas Burners.
I, CHARLES CLAMOND, of 15 Rue Picot, Paris, in the Republic of France,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has reference to a safety gas burner, so constructed that when
the cock or valve is opened it will be held open by the action of the flame of the
gas when the same is ignited, but will be automatically closed when the gas is not
ignited, or when, after ignition, the flame dies out for any reason, thus preventing
the escape of gas and all the injurious influences resulting therefrom.
It is well known that a great many safety gas burners have been constructed
aiming to secure this object, but all of them have certain defects which I shall
presently point out and which my invention is designed to overcome.
In the following detail description references will be had to the accompanying
drawing in which :-
Figure 1, is a side elevation partly in section of a common type of safety gas
burners upon which my invention aims to improve.
Figure 2 is an elevation partly in section of a safety gas burner embodying one
of the principles of my invention, and
Figure 3 is a plan view partly in section of the same.
Figure 4, is a vertical section of an ordinary pin-hole gas burner illustrating the
shape of the flame produced thereby.
Figures 5, 6 and 7 illustrate vertical sections of pin-hole gas burners embodying
another principle of my invention, and
Figure 8 is a vertical section of a bat-wing gas burner embodying the same
improvement.
Figure 9 is a side elevation partly in section of a safety gas burner embodying
my invention as adapted for commercial use, and
Figures 10 and 11 are end elevations of the same, showing the mechanism in the
open and closed positious, respectively.
Figure 12 is a vertical section of the latch mechanism of my commercial form
of burner, and
Figure 13 is a perspective view of the latch.
Like numerals of reference indicate like parts.
In order that a clear understanding of my invention may be obtained, it is
necessary to contemplate the general principles upon which safety gas burners
have heretofore been made, and in order to facilitate this, a typical but otherwise
fictitious gas burner of that kind has been illustrated in Figure 1.
In this figure 1 represents the gas pipe having a cock or valve, 2, which, by a
spring, 3, is normally held in the closed position. The gas pipe has at its upper end
a burner tip, 4, which in the present instance is supposed to be a bat-wing tip,
giving a flame of the kind indicated at 5. A thermostatic plate, 6, composed of
two strips of unequally expansible metals is brought within the heating influence
of the flame and is, at one end, 7, fixed to the burner pipe 1, while its free end, 8,
is pivotted to a link 9, which in turn is pivotally connected with a sliding rod 10,

page_text: which passes through a guide, 11, into the path of an arm 12, fixed to the valve
stem so as to rotate with it.
When, in a device of this kind, the gas is not lit the thermostatic plate is
supposed to have the form indicated in dotted lines, in which case the free end of
the sliding rod, 10, will be a little distance to the left beyond the left hand side of
the arm 12, so that the latter may be moved with the valve to pass the line
of movement of the rod, 10, when the valve is being opened. In the device as
shown in the drawing, the valve is in the open position and the gas ignited;
consequently, in an apparatus of this kind, supposing that the more expansible
metal of the thermostatic plate is on the outside, the latter has become more
convex, until the free arm 8 is moved to the position shown in solid lines, and
consequently the sliding rod, 10, has projected beyond the plane of movement of
the arm 12, which latter is thereby prevented from turning under the influence of
the spring 3. The valve or cock is therefore held open by the action of the heat
of the flame upon the thermostatic plate.
The defects of a device of this kind are very apparent.
Suppose that the free end of the rod, 10, is normally a considerable distance
from the plane of movement of the arm 12, say, for instance, in a position marked
by the letter, and the cock is opened and the gas iguited. It will be seen that
the cock must be held open by hand until the thermostatic plate has become
heated enough to curve sufficiently to bring the free end of the rod, 10, beyond
the edge of the arm 12. This takes as much as a minute or more, which is
a great inconvenience. If the valve is released before the rod, 10, has advanced
into the path of the arm, 12, it will not remain open but will be instantly closed
by the spring 3. In order to avoid this difficulty the construction is ordinarily
made so that the free end of the rod, 10, is very close to, but still on the
left side of, the path of the arm, 12, so that only a short time, say a few
seconds, is required to bring the free end of rod, 10, into the path of the arm 12.
But when this is done another and much more serious difficulty arises, which
consists in the continued heating, the continued curving and the continued
inward movement of the free end of the plate 6, whereby the rod, 10, is projected
an unreasonably long distance across the path of the arm 12. This condition is
shown in the drawing. It results from this that if now from any reason the flame
should go out the valve cannot be closed by the spring, 3, until after the plate, 6,
has cooled down to its normal temperature and the rod 10 thereby withdrawn from
the path of the arm 12. This sometimes takes as much as two minutes of time,
and during this time the gas is permitted to escape freely.
In addition thereto, by the repeated heating and cooling of the plate, 6, the
elasticity of the latter and its normal shape are varied in either of two ways.
First, it may happen that the normal shape of the thermostatic plate becomes such
as to bring the free en:1 of the rod 10 a considerable distance away from the plane
of movement of the arm 12, so that it now requires a still longer time, after
lighting the gas, before the valve will be kept automatically open; and second, it
may happen that the changed normal condition of the plate, 6, will bring the free
end of rod, 10, into the path of the arın 12, in which case the valve caunot be kept
open at all.
These are the main but by no means all the defects inherent in the ordinary
safety gas burners heretofore made; and I shall now explain the manner in which
I overcome these defects by my invention.
Referring to Figures 2 and 3, it will be seen that the free end of the thermo-
static plate 6 is pivotted to two parallel links 9, 9, to which in turn is pivotted, by
the trunnions 13, the block 14, which hereinafter will be referred to as the
"friction block." This triction block has a central bore through which the sliding
rod, 10, passes, and is held therein by gentle friction. The friction block may be
secured in any suitable known manner, as, for instance, by a close fit or by a spring,
or by making either the block or the rod, 10, a permanent magnet while the other
part is made of soft iron.

page_text: The sliding rod, 10, also passes through the guide block, 11, with no appreciable
friction; and it has fixed to it, very near the points where it emerges from
the guide block, the stop-pins 101 and 10%, respectively, so that the distance
between the two stop-pins is only a very little greater that the length of the
guide block 11. The normal position of the sliding rod, 10, is such that the
stop-pin, 10%, abuts against the guide block, and then the right hand end of
the rod, 10, just clears the plane of movement of the arm 12, so that the
cock or valve can be opened. If now the valve is opened, the gas ignite.l
and the thermostatic plate, 6, is heated by the flame, its free end, 8, will move
toward the right thus impelling the links, 9, the friction block, 14, and the sliding
rod, 10, which is held therein frictionally, toward the right, since the rod, 10,
moves without perceptible friction through the guide block. This movement will
continue until the stop-pin, 101, comes in contact with the left hand end of the
guide block, and by this time the free end of the rod, 10, will have passed beyond
the plane of the adjacent surface of the arm 12, so that the cock or valve will now
be held open and prevented from closing by the action of the spring 3. For this
purpose only an exceedingly small movement of the rod, 10, is required, a
movement which, by the heating action of the flame upon the thermostatic plate,
is produced in a very few seconds. A continued heating and consequent curving
of the thermostatic plate has no effect upon the sliding rod 10, since the same is
stopped from further movement toward the right; but the friction block 14, now moves
over the rod, 10, until the thermostatic plate, 6, has reached its highest temperature.
If now, for any reason, the flame should become extinguished, the thermostatic
plate, 6, would at once begin to cool and its free end, 8, would move toward the left,
taking with it the links 9, the friction block 14, and the sliding rod 10, which would
thus pass out of the path of the arm, 12, until the stop-pin, 10%, comes in contact with
the right hand end of the guide block 11. This movement is effected in a very few
seconds so that no appreciable amount of gas can escape, since the very instant
when the rod, 10, has passed the plane of the left hand face of the arm 12, the
cock or valve is shut by the spring 3. The continued cooling of the plate, 6, has
no effect upon the sliding rod, 10, as will now be readily understood. All that
happens is that the link with the friction block, 14, is drawn further toward the
left. It is thus clear that by the interposition of the friction coupling between the
rod, 10, and the thermostatic plate the movement of the rod 10, (which here
assumes the function of a latch,) is limited in both directions by the stop-pins 10'
and 10%. This movement may be made as small as desired, so that any appreciable
heating or cooling of the thermostatic plate will produce the maximum movement
of the latch, thus locking or releasing the cock or valve instantaneously.
If this invention is applied to safety gas burners, the thermostatic plate must be
placed under the influence of such part of the flame as remains practically constant
whatever the size of the flame may be. This will be readily understood if it is
considered that if the plate, 6, were arranged with reference to the flame in the
manner shown in Figure 1, any reduction of the flame, such as may be caused by
a momentary decrease of gas pressure, would cool the plate, 6, sufficiently to cause
a movement of its free end, 8, and the gas would be instantly and untimely cut off in
the manner hereinbefore described. On the other hand, if the gas pressure should
momentarily increase above the normal and then again drop down to normal, the
cooling of the thermostatic plate at the drop of pressure would again instantly cut
off the gas. It is thus impracticable to place the thermostatic plate with reference
to the flame in such position that the beating of the same is dependent upon the
size of the flame. To work well the thermostatic plate, when connected to the
latch by a friction coupling, must be heated equally whether the flame is large or
small and this result is secured by the second part of my invention, which I shall
presently describe.
In Figure 4 is represented as ordinary pin-hole gas burner giving a flame shaped
similar to that of an ordinary candle, that is to say, the portion of the flame nearest
to the opening is contracted as shown at 5'.

page_text: In Figure 5 the burner tip, 4, is shown as provided with a cap, 15, forming a small
expansion chamber, 16, which when the cock is opened is filled with gas and
prevents the access of air. The gas therefore comes to combustion at the upper edge
of the cap, 15. so that the flame spreads over and covers the upper edge of the cap as
indicated at 52. Immediately above this point the flame is contracted, as indicated
at 53, and then again swells out and finally terminates in a point, the same as the
flame in the ordinary pin-hole burner. The portion 52 of the flame, which will
hereinafter be called the expanded base of the flame, remains practically constant
whatever the gas pressure may be; and constitutes a heating agent which is
independent of the fluctuations in the size of the flame proper. It will now be
understood that if the thermostatic element used in connection with a safety gas
burner is exposed to the heating influence of the expanded base of the flame
produced by the expansion chamber, 16, it will set promptly when the gas is lit, no
matter how small the flame may be, and will remain indifferent to variations in the
size of the flame. My invention, therefore, comprises, among other things, a
safety gas burner, the thermostatic element of which is exposed to the heating
influence of a practically invariable expanded base of the flame. This part of my
invention is useful whether it is coupled with the mechanism for limiting the
movement of the latch, described with reference to Figures 2 and 3, or whether it
is used in connection with any other safety gas burner mechanism. It is immaterial
in this connection whether the thermostatic element consists of metal or any other
material. Thus for instance in Figure 6, 1 have shown an embodiment of this
part of my invention in which the thermostatic element is a fluid. In this case the
cap, 15, has a closed receptacle, 18, which may contain either a gas or a liquid, and
in addition thereto it is formed with the expansion chamber, 16, upon the upper
edge of which the permanent base 52 of the flame is formed, and which, heating
the fluid within the receptacle, 18, expands the same and causes it to act upon the
latch for locking or releasing the spring actuated valve or cock. For this purpose
a small pipe or tube, 19, is led from the receptacle 18 to the latch controlling
mechanism.
In Figure 7, the thermostatic element is represented as composed of two
unequally expansible metallic plates, 6, one end, 7, of which is fast on the gas
pipe 1, and is then curved over and in contact with the burner tip and has an
expansion chamber 16 coincident with the pin-hole opening in the tip. In this case
the permanent base 52 of the flame heats the metallic strips composing the thermo-
static element, the free end of which, it will now be understood, is connected with
links 9, 9, substantially in the manner shown in Figures 2 and 3, or with any other
mechanism which embodies the same fundamental principle.
In Figure 8, the burner tip 4 has a slot instead of a pin-hole, and thus furnishes
a bat-wing flame. Consequently the expansion chamber 16, formed in the thermo-
static plate 6, is in this case shaped to conform to the slot, that is to say, to surround
the burner slot. In all other respects the construction is the same as that shown in
Figure 7.
For the practical embodiment of my invention I have devised a structure which
is illustrated in Figures 9 to 13, inclusive.
In the construction shown in these figures the thermostatic portion of plate 6 is
reduced in length, as shown, since it is unnecessary to extend it much beyond the
portion directly heated by the flame. The expansion chamber 16 is formed in
the middle of the thermostatic portion of plate 6, and the end 7 of this plate is
secured to a collar, 20, which freely slides on the burner pipe, but is secured
against accidental displacement on the same by a pin, 21, projecting from the
burner pipe into a slot, 22, formed in the collar. The thermostatic plate thus
rests by gravity upon the burner tip and any longitudinal movement of the side
terminating in the end 7 will be taken up by the movement of the collar and
consequently there will always be a tight fit between the thermostatic plate and
the burner tip so that no air can enter the expansion chamber from below.
The other end 8 of the thermostatic plate is connected by a link, 9, to the lower

page_text: end of a U-shaped spring, 141, which as will presently be seen performs the
function of the friction block 14 of the structure shown in Figures 2 and 3. The
upper ends of the two arms constituting the U-shaped spring are perforated and
receive a hub 23 projecting laterally from one end of a latch, 24, which latter, as.
will presently be seen, performs the function of the sliding rod 10. The hub, 23,
has a reduced axial extension, 24, on which is secured, in any suitable manner, a
washer, 25, confining the two arms of the spring 14' between it and the latch,
which latter is secured to the burner by a screw 26 passing centrally through the
hub. The spring 14' is so constructed that the two arms tend to move outwardly
when confined between the latch and the washer 25, so that they bear with more
or less friction against the same; but if the latch be held against movement the
spring may be moved around the hub as a centre. The latch has its movement
around the screw, 26, limited by a pin, 27, rising from the burner and entering a
slot 28 formed in the latch.
The cock or valve 2 is provided with a laterally extending arm, 29, to which is
attached a cord, 30, or other means for turning the valve from the close position
indicated in Figure 11 to the open position shown in Figure 10, against the action
of the spring 3. Extending across the face of the valve is an arm, 31, pivotted to
the burner below the valve and of such length that its upper end, 32, when the
arm is moved on its pivot, will strike the lower edge of the latch 24. This upper
end of the arm is bevelled so that it will raise the latch and ride under it when
moved in the proper direction. The movement of the arm from the position
shown in Figure 11 toward that shown in Figure 10 is effected by the movement
of the valve toward the open position. On the face of the valve is a pin, 33,
placed eccentrically, and as the valve is turned toward the open position this pin
engages a shoulder, 34, on the arm 31 and thereby moves the latter around its
pivot until its upper end 32 has passed under the latch. It will be understood
that the latch being held with some friction by the spring 141 will remain in the
raised position and as the gas will now be turned on it is only necessary to light
the gas in order that the thermostatic plate will, by means of the link 9 and
spring 14', lower the latch into the path of the upper end 32 of the arm 31 and
thereby prevent the latter from returning to its first position. On the arın 31
opposite the shoulder 34 is a tooth 35, separated from the shoulder by a slight
recess, into which the pin 33 passes when the valve is turned to the open position;
and this tooth 35 prevents the return of the valve to the closed position, under the
action of the spring 3, by engaging the pin 33.
Should the gas light become extinguished the thermostatic plate on cooling
will lift the latch from out the path of the arm 31 and the pin 33, which engages
the tooth 35, will then throw the arm to the position shown in Figure 11, and the
valve will be free to return to the closed position under the action of the
spring 3.
In the commercial structure here described the movement of the latch is
limited by the length of the slot 28, which may be very short, while the
thermostatic plate may move through a considerable distance since the spring, 14',
will move on the hub 23 of the latch when the latter is stopped in either the
raised or lowered position, as will now be readily understood.
It will be understood, that my invention may be embodied in structures widely
differing in form from those herein described. I am therefore not limited to the
particular mechanism shown, since the same can be freely varied and changed
without departing from the fundamental principles upon which my invention is
based.
Daadhi 15th
T
1908

page_text: I, CHARLES CLAMOND, of 15 Rue Picot, Paris, in the Republic of France,
Engineer, 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 has reference to a safety gas burner, so constructed that when
the cock or valve is opened it will be held open by the action of the flame of
the gas when the same is ignited, but will be automatically closed when the
gas is not ignited, or when, after ignition, the flame dies out for any reason,
thus preventing the escape of gas and all the injurious influences resulting
therefrom.
It is well known that a great many safety gas burners have been constructed
aiming to secure this object, but all of them have certain defects which I shall
presently point out and which my invention is designed to overcome.
In the following detailed description references will be made to the drawing left
with the Provisional Specification, in which :-
:―
Figure 1, is a side elevation partly in section of a common type of safety gas
burners upon which my invention aims to improve ;
Figure 2 is an elevation partly in section of a safety gas burner embodying one
of the principles of my invention, and
Figure 3 is a plan view partly in section of the same.
Figure 4 is a vertical section of an ordinary pin-hole gas burner illustrating the
shape of the flame produced thereby.
Figures 5, 6 and 7 illustrate vertical sections of pin-hole gas burners embodying
another principle of my invention, and
Figure is a vertical section of a bat-wing gas burner embodying the same
improvement.
Figure 9 is a side elevation partly in section of a safety gas burner embodying
my invention as adapted for commercial use, and
Figures 10 and 11 are end elevations of the same, showing the mechanism in the
open and closed positions, respectively.
Figure 12 is a vertical section of the latch mechanism of my commercial form of
burner, and
Figure 13 is a perspective view of the latch.
Like numerals of reference indicate like parts.
In order that a clear understanding of my invention may be obtained, it is
necessary to contemplate the general principles upon which safety gas burners
have heretofore been made, and in order to facilitate this, a typical but otherwise
fictitious gas burner of that kind has been illustrated in Figure 1.
In this figure 1 represents the gas pipe having a cock or valve, 2, which, by a
spring, 3, is normally held in the closed position. The gas pipe has at its upper
end a burner tip, 4, which in the present instance is supposed to be a bat-wing tip,
giving a flame of the kind indicated at 5. A thermostatic plate, 6, composed of
two strips of unequally expansible metals is brought within the heating influence
of the flame, and is at one end, 7, fixed to the burner pipe 1, while its free end, 8
is pivotted to a link, 9, which in turn is pivotally connected with a sliding rod 10,
which passes through a guide, 11, into the path of an arm 12 fixed to the valve
stem so as to rotate with it.
When in a device of this kind the gas is not lit the thermostatic plate is
supposed to have the form indicated in dotted lines in which case the free end of
the sliding rod, 10, will be a little distance to the left beyond the left hand side of
the arm 12, so that the latter may be moved with the valve to pass the line

page_text: of movement of the rod, 10, when the valve is being opened. In the device as
shown in the drawing, the valve is in the open position and the gas ignited;
consequently, in an apparatus of this kind, supposing that the more expansible
metal of the thermostatic plate is on the outside, the latter has become more
convex, until the free arm 8 is moved to the position shown in solid lines, and
consequently the sliding rod, 10, has projected beyond the plane of movement of
the arm 12, which latter is thereby prevented from turning under the influence of
the spring 3. The valve or cock is therefore held open by the action of the heat
of the flame upon the thermostatic plate.
The defects of a device of this kind are very apparent.
Suppose that the free end of the rod, 10, is normally a considerable distance
from the plane of movement of the arm 12, say, for instance, in a position marked
by the letter, and the cock is opened and the gas ignited. It will be seen that
the cock must be held open by hand until the thermostatic plate has become
heated enough to curve sufficiently to bring the free end of the rod, 10, beyond
the edge of the arm 12. This takes as much as a minute or more, which is a
great inconvenience. If the valve is released before the rod, 10, has advanced to
the path of the arm, 12, it will not remain open but will be instantly closed by the
spring 3. In order to avoid this difficulty the construction is ordinarily made so that
the free end of the rod, 10, is very close to, but still on the left side of, the path of the
arm, 12, so that only a short time say a few seconds, is required to bring the free
end of rod, 10, into the path of the arm 12. But when this is done another and
much more serious difficulty arises, which consists in the continued heating, the
continued curving and the continued inward movement of the free end of the
plate 6, whereby the rod, 10, is projected an unreasonably long distance across
the path of the arm 12. This condition is shown in the drawing. It results from
this that if now from any reason the flame should go out the valve cannot be closed
by the spring, 3, until after the plate, 6, has cooled down to its normal temperature
and the rod 10 thereby withdrawn from the path of the arm 12. This sometimes
takes as much as two minutes of time, and during this time the gas is permitted to
escape freely.
In addition thereto, by the repeated heating and cooling of the plate, 6, the
elasticity of the latter and its normal shape are varied in either of two ways.
First, it may happen that the normal shape of the thermostatic plate becomes
such as to bring the free end of the rod 10 a considerable distance away from the
plane of movement of the arm 12, so that it now requires a still longer time, after
lighting the gas, before the valve will be kept automatically open; and, second, it
may happen that the changed normal condition of the plate, 6, will bring the free
end of rod, 10, into the path of the arm 12, in which case the valve cannot be
kept open at all.
These are the main but by no means all the defects inherent in the ordinary
safety gas burners heretofore made; and I shall now explain the manner in
which I overcome these defects by my invention.
Referring to Figures 2 and 3, it will be seen that the free end of the
thermostatic plate 6 is pivotted to two parallel links 9, 9, to which in turn is
pivotted by the trunnions 13, the block 14, which hereinafter will be referred to
as the "friction block." This friction block has a central bore through which the
sliding rod, 10, passes, and is held therein by gentle friction. The friction block
may be secured in any suitable and known manner, as, for instance, by a close
fit or by a spring, or by making either the block or the rod, 10, a permanent
magnet while the other part is made of soft iron.
The sliding rod, 10, also passes through the guide block, 11, with no appreciable
friction; and it has fixed to it, very near the points where it emerges from the
guide block, the stop-pins 10¹ and 10%, respectively, so that the distance between
the two stop-pins is only a very little greater than the length of the guide
block 11. The normal position of the sliding rod, 10, is such that the stop-pin, 102,
abuts against the guide block, and then the right hand end of the rod, 10, just

page_text: clears the plane of movement of the arm 12, so that the cock or valve can be
opened. If now the valve is opened, the gas ignited and the thermostatic plate, 6,
is heated by the flame, its free end, 8, will move toward the right thus impelling
the links, 9, the friction block, 14, and the sliding rod, 10, which is held therein
frictionally, toward the right, since the rod, 10, moves without perceptible friction
through the guide block. This movement will continue until the stop-pin, 10',
comes in contact with the left hand end of the guide block, and by this time the
free end of the rod, 10, will have passed beyond the plane of the adjacent surface
of the arm 12, so that the cock or valve will now be held open and prevented
from closing by the action of the spring 3. For this purpose only an exceedingly
small movement of the rod, 10, is required, a movement which, by the heating
action of the flame upon the thermostatic plate, is produced in a very few seconds. A
continued heating and consequent curving of the thermostatic plate has no effect upon
the sliding rod, 10, since the same is stopped from further movement toward the
right; but the friction block 14, now moves over the rod, 10, until the thermostatic
plate, 6, has reached its highest temperature.
If now, for any reason, the flame should become extinguished, the thermostatic
plate, 6, would at once begin to cool and its free end, 8, would move toward the
left, taking with it the links 9, the friction block 14, and the sliding rol 10,
which would thus pass out of the path of the arm, 12, until the stop-pin, 102,
comes in contact with the right hand end of the guide block 11. This movement
is effected in a very few seconds so that no appreciable amount of gas can escape,
since the very instant when the rod, 10, has passed the plane of the left hand face
of the arm 12, the cock or valve is shut by the spring 3. The continued cooling
of the plate, 6, has no effect upon the sliding rod, 10, as will now be readily
understood. All that happens is that the link with the friction block, 14, is
drawn further toward the left. It is thus clear that by the interposition of the
friction coupling between the rod, 10, and the thermostatic plate the movement
of the rod 10, (which here assumes the function of a latch) is limited in both
directions by the stop-pius 101 and 10%. This movement may be made as small as
desired, so that any appreciable heating or cooling of the thermostatic plate will
produce the maximum movement of the latch, thus locking or releasing the cock
or valve instantaneously.
If this invention is applied to safety gas burners, the thermostatic plate must
be placed under the influence of such part of the flame as remains practically
constant whatever the size of the flame may be. This will be readily understood
if it is considered that if the plate, 6, were arranged with reference to the flame in
the manner shown in Figure 1, any reduction of the flame, such as may be caused
by a momentary decrease of gas pressure, would cool the plate, 6, sufficiently to
cause a movement of its free end, 8, and the gas would be instantly and untimely
cut off in the manner hereinbefore described. On the other hand, if the gas
pressure should momentarily increase above the normal and then again drop
down to normal, the cooling of the thermostatic plate at the drop of pressure
would again instantly cut off the gas. It is thus impracticable to place the
thermostatic plate with reference to the flame in such position that the heating of
the same is dependent upon the size of the flame. To work well the
thermostatic plate, when connected to the latch by a friction coupling, must be
heated equally whether the flame is large or small and this result is secured
by the second part of my invention, which I shall presently describe.
In Figure
is represented an ordinary pin-hole gas-burner giving a flame
shaped similar to that of an ordinary candle, that is to say, the portion of the
flame nearest to the opening is contracted as shown at 5¹.
In Figure 5 the burner tip, 4, is shown as provided with a cap, 15, forming a
small expansion chamber, 16, which when the cock is opened is filled with gas
and prevents the access of air. The gas therefore comes to combustion at the
upper edge of the cap, 15, so that the flame spreads over and covers the upper
edge of the cap as indicated at 52. Immediately above this point the flame is

page_text: contracted, as indicated at 53, and then again swells out and finally terminates in a
point, the same as the flame in the ordinary pin-hole burner. The portion 5% of
the flame, which will hereinafter be called the expanded base of the flame, remains
practically constant whatever the gas pressure may be; and constitutes a heating
agent which is independent of the fluctuations in the size of the flame proper. It
will now be understood that if the thermostatic element used in connection with a
safety gas burner is exposed to the heating influence of the expanded base of the
flame produced by the expansion chamber, 16, it will set promptly when the gas
is lit, no matter how small the flame may be, and will remain indifferent to
variations in the size of the flame. My invention, therefore, comprises, among
other things, a safety gas burner, the thermostatic element of which is exposed to
the heating influence of a practically invariable expanded base of the flame.
This part of my invention is useful whether it is coupled with the mechanism
for limiting the movement of the latch, described with reference to Figures 2
and 3, or whether it is used in connection with any other safety gas burner
mechanism. It is immaterial in this connection whether the thermostatic element
consists of metal or any other material. Thus for instance in Figure 6, I have
shown an embodiment of this part of my invention in which the thermostatic
element is a fluid. In this case the cap, 15, has a closed receptacle, 18, which
may contain either a gas or a liquid, and in addition thereto it is formed with
the expansion chamber, 16, upon the upper edge of which the permanent base 5*
of the flame is formed, and which, heating the fluid within the receptacle, 18,
expands the same, and causes it to act upon the latch for locking or releasing
the spring actuated valve or cock. For this purpose a small pipe or tube, 19, is
led from the receptacle 18 to the latch controlling mechanism.
In Figure 7, the thermostatic element is represented as composed of two
unequally expansible metallic plates, 6, one end, 7, of which is fast on the gas
pipe 1, and is then curved over and in contact with the burner tip and has an
expansion chamber 16 coincident with the pin-hole opening in the tip. In this
case the permanent base 52 of the flame heats the metallic strips composing the
thermostatic element, the free end of which, it will now be understood, is connected
with links 9, 9, substantially in the manner shown in Figures 2 and 3, or with any
other mechanism which embodies the same fundamental principle.
In Figure 8, the burner tip 4 has a slot instead of a pin-hole, and thus furnishes
a bat-wing flame. Consequently the expansion chainber 16, formed in the
thermostatic plate 6, is in this case shaped to conform to the slot, that is to say, to
surround the burner slot. In all other respects the construction is the same as that
shown in Figure 7.
For the practical embodiment of my invention I have devised a structure which
is illustrated in Figures 9 to 13, inclusive.
In the construction shown in these figures the thermostatic portion of plate 6 is
reduced in length, as shown, since it is unnecessary to extend it much beyond the
portion directly heated by the flame. The expansion chamber 16 is formed in the
middle of the thermostatic portion of plate 6, and the end 7 of this plate is secured
to a collar, 20, which freely slides on the burner pipe, but is secured against
accidental displacement on the same by a pin, 21, projecting from the burner pipe
into a slot, 22, formed in the collar. The thermostatic plate thus rests by gravity
upon the burner tip and any longitudinal movement of the side terminating in the
end 7 will be taken up by the movement of the collar and consequently there will
always be a tight fit between the thermostatic plate and the burner tip so that no
air can enter the expansion chamber from below.
The other end 8 of the thermostatic plate is connected by a link, 9, to the lower
end of a U-shaped spring, 14', which as will presently be seen performs the
function of the friction block 14 of the structure shown in Figures 2 and 3. The
upper ends of the two arms constituting the U-shaped spring are perforated and
receive a hub 23 projecting laterally from one end of a latch, 24, which latter; as
will presently be seen, performs the function of the sliding rod 10. The hub, 23,
B

page_text: has a reduced axial extension, 24¹, on which is secured, in any suitable manner, a
washer, 25, confining the two arms of the spring 141 between it and the latch,
which latter is secured to the burner by a screw, 26, passing centrally through the
hub. The spring 14' is so constructed that the two arms tend to move outwardly
when confined between the latch and the washer 25, so that they bear with
more or less friction against the same; but if the latch be held against movement
the spring may be moved around the hub as a centre. The latch has its movement
round the screw, 26, limited by a pin, 27, rising from the burner and entering a
slot 28 formed in the latch.
The cock or valve 2 is provided with a laterally extending arm, 29, to which is
attached a cord, 30, or other means for turning the valve from the closed
position indicated in Figure 11 to the open position shown in Figure 10, against
the action of the spring .3. Extending across the face of the valve is an arm, 31,
pivotted to the burner below the valve and of such length that its upper end, 32,
when the arm is moved on its pivot, will strike the lower edge of the latch 24.
This upper end of the arm is bevelled so that it will raise the latch and ride under
it when moved in the proper direction. The movement of the arm from the
position shown in Figure 11 toward that shown in Figure 10 is effected by the
movement of the valve toward the open position. On the face of the valve is a
pin, 33, placed eccentrically, and as the valve is turned toward the open position
this pin engages a shoulder, 34, on the arm 31 and thereby moves the latter
around its pivot until its upper end 32 has passed under the latch. It will be
understood that the latch being held with some friction by the spring 14' will
remain in the raised position and as the gas will now be turned on it is only
necessary to light the gas in order that the thermostatic plate will, by means of
the link 9 and spring 14', lower the latch into the path of the upper end 32 of the
arm 31 and thereby prevent the latter from returning to its first position. On the
arm 31 opposite the shoulder 34 is a tooth 35, separated from the shoulder by a
slight recess, into which the pin 33 passes when the valve is turned to the open
position; and this tooth 35 prevents the return of the valve to the closed position,
under the action of the spring 3, by engaging the pin 33.
Should the gas light become extinguished the thermostatic plate on cooling will
lift the latch from out of the path of the arm 31 and the pin 33, which engages the
tooth 35, will then throw the arm to the position shown in Figure 11, and the
valve will be free to return to the closed position under the action of the
spring 3.
In the commercial structure here described the movement of the latch is limited
by the length of the slot 28, which may be very short, while the thermostatic plate
may move through a considerable distance since the spring, 14', will move on the
hub 23 of the latch when the latter is stopped in either the raised or lowered
position, as will now be readily understood.
It will be understood that my invention may be embodied in structures widely
differing in form from those herein described. I am therefore not limited to the
particular mechanism shown, since the same can be freely varied and changed
without departing from the fundamental principle upon which my invention is based.
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. In a safety gas burner, the combination of a thermostatic element within the
heating influence of the flame of the burner, with a latch for locking and unlocking
a cock or valve of the burner, a friction coupling between the latch and the
thermostatic element, and stops for limiting the movement of the latch, substantially
as described.
2. In a safety gas burner, the combination of a self closing cock or valve and a
latch for locking and unlocking the same; with a thermostatic element within
the heating influence of the flame, a friction coupling between the latch and

page_text: thermostatic element and stops for limiting the movement of the latch, substantially
as described.
3. In a safety gas burner, the combination of a self closing cock or valve, and
a latch capable of a limited movement in two directions for locking an 1 unlocking
the valve, respectively; with a thermostatic element within the heating influence
of the flame and a friction coupling between the latch and the thermostatic element,
substantially as described.
4. In a safety gas burner, the combination of a self closing cock or valve, a
latch capable of a limited movement in two directions for locking and unlocking
the valve, respectively, a thermostatic element within the heating influence of
the flame and a coupling between the thermostatic element and latch composed of
two or more friction joints capable of slipping past each other when the latch is
stopped from following the impulse of the thermostatic element, whereby the latch.
will be moved to an extreme position by the initial movements of the thermostatic
element in either direction; substantially as described.
5. In a safety gas burner, the combination of a burner tip and a thermostatic
element exposed to the heating influence of an invariable portion of the flame;
with a latch for locking or unlocking a cock or valve of the burner, a friction
coupling between the latch and thermostatic element, and stops for limiting the
movements of the latch, substantially as described.
6. In a safety gas burner, the combination of a burner tip and a thermostatic
element producing a flame with an invariable expanded base in contact with the
thermostatic element, substantially as described.
7. A gas-cut-off burner having its outlet surrounded by a thermostatic element
forming an expansion chamber above which the gas burns with an invariable
expanded base in contact with the top of the thermostatic element, substantially as
described.
8. A safety gas burner having a thermostatic element formed with an expansion.
chamber surrounding the gas exit opening of the tip and thus heated by an
invariable expanded base of the flame, in combination with a self closing cock
or valve, a latch having limited movements in two directions for locking and
unlocking the valve, and a friction coupling between the thermostatic element
and the latch, substantially as described.
9. In a safety gas burner, the combination of a burner tip and a thermostatic
element closely fitting to the top of the tip and formed with an expansion
chamber surrounding the gas exit opening of the tip, whereby the flame is shaped
with an invariable expanded base in contact with the thermostatic element,
substantially as described.
10. In a safety gas burner, the combination with a burner tip and a thermostatic
element producing a flame with an invariable expanded base in contact with the
thermostatic element; of a self closing cock or valve, a latch having limited
movements in two directions for locking and unlocking the valve, and a friction
coupling between the thermostatic element and the latch constructed to slip when
the latch has reached the limit of its movement in either direction, substantially
as described.
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