Im- .PROVEMENTS IN THE CONSTRUCTION OF MINERS OR SAFETY LAMPS
Year: 1870

page_text: LETTERS PATENT to James Allison Hogg, of Chancery Lane, in
the County of Middlesex, Gentleman, for the Invention of "Im-
.PROVEMENTS IN THE CONSTRUCTION OF MINERS OR SAFETY LAMPS."
Sealed the 31st December 1870, and dated the 23rd August 1.870.
PROVISIONAL SPECIFICATION left by the said James Allison Hogg
at the Office of the Commissioners of Patents, with his Petition, on
the 23rd August 1870.
I, JAMES ALLISON HOGG, of Chancery Lane, in the County of Mid-
3 dlesex, Gentleman, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF MINERS OR SAFETY LAMPS," to be
as follows:-
:―
My Invention of improvements in miners or safety lamps relates to
an improved mode of constructing that class of lamp in which the
external air is prevented from coming into contact with the flame
except in such a manner as will obviate the chance of igniting the
external air should it contain any combustible or explosive gases. There
are various constructions of lamps used for this purpose, but the pro-

page_text: tecting medium (consisting generally of wire gauze) prevents the
transmission of a large portion of the light from the flame. The miners
find this light so feeble as to interfere materially with their operations,
and have frequently removed the protecting gauze from the lamp,
(of course at the risk of producing an explosion) for the purpose of
obtaining additional light to work by. This removal of the protecting
gauze is fraught with so much danger that miners' lamps are now made.
in such a manner that the gauze is locked on to the lamp and cannct
be very easily removed by the miner.
My Invention has for its object; first, to increase the amount of power
of the light transmitted from the flame through the protecting medium;
_second, to diminish the quantity of the combustible liquid consumed by
the wick; third, adapting to the lamp a device for extinguishing the
flame in the event of an attempt being made to remove the gauze or
protecting medium; fourth, a device for preventing the workman from
obtaining access to the flame by perforating the protecting wire gauze.
In carrying out my Invention I increase the power of the light by
adapting to the lamp a convex, plano-convex, or other suitable lens,
(either simple or compound,) and causing the light from the lamp to
pass through such lens. To this end a part of the wire gauze is cut
away and the lens mounted in a suitable frame is adapted thereto. A
piece of talc may be placed at the back of the lens, so that in the event
of the latter being accidentally broken. the external air will still be
prevented from obtaining access to the flame. A reflector is placed
behind the flame and throws the rays of light through the lens in front.
By these arrangements I find by experiment that the amount of power
of the light transmitted from the flame is increased nearly twenty-fold, I
am therefore enabled to reduce the size of the wick and consequently
diminish the quantity of oil or other combustible liquid consumed, and
thereby effect a considerable economy. The device for extinguishing
the light when any attempt is made to remove the wire gauze or other
protecting medium consists of a trip lever to which a disc or extinguisher
is adapted, and which is maintained in a vertical position by means of a
detent, the lower end of which extends downwards and bears, against
the periphery of a ratchet rack or against studs made on or attached to:
the body of the lamp and surrounding the wick tube. When the lamp
is unscrewed the teeth of the ratchet come against the tail of the detent
lever and push it on one side, so as to release the vertical lever which

page_text: carries the extinguisher. Immediately this is released the latter is
forced down by means of a spring on to the wick and extinguishes the
flame. The extinguisher may be made in the form of a disc, and this
disc may be made to act as a reflector to throw the light through the
lens, or the reflector may be separate.
The next improvement consits in the use of a tale cylinder which is
placed inside the wire gauze cylinder and will prevent the workman
from obtaining access to the flame even if he perforates the wire gauze.
The lens for increasing the light and also the extinguishing device may
be adapted to the Clanny and other kinds of safety lamps. The brass
or other metal frame which carries the lens may either be hinged to one
of the vertical rods which surround the glass cylinder of the Clanny
lamp, or to the horizontal plates in which the vertical rods are secured.
Safety lamps constructed in the manner herein set forth may be
used in mines, collieries, underground workings, ships' holds, powder
magazines, and other places where such lamps may be required.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Allison Hogg in the Great Seal Patent
Office on the 22nd February 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
ALLISON HOGG, of Chancery Lane, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of August, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said James Allison Hogg, Her special
licence, that I, the said James Allison Hogg, my executors, adminis-
trators, and assigns, or such others as I, the said James Allison Hogg,
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 "IMPROVEMENTS

page_text: IN
THE CONSTRUCTION OF MINERS OR SAFETY LAMPS," upon the condition
(amongst others) that I, the said James Allison Hogg, 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 Seal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Allison Hogg, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the Drawings here-
unto annexed and to the letters-and-figures-marked thereon_(_that_is_
to say).
My Invention of improvements in miners or safety lamps relates to
an improved mode of constructing that class of lamp in which the
external air is prevented from coming into contact with the flame, except
in such a manner as will obviate the chance of igniting the external
air should it contain any combustible or explosive gases. There are
various constructions of lamps used for this purpose, but the protecting
medium (consisting generally of wire gauze) prevents the transmission
of a large portion of the light from the flame. The miners find the
light of such lamps so feeble as to interfere materially with their
operations and have frequently removed the protecting gauze from the
lamp. (of course at the risk of producing an explosion), for the purpose
of obtaining additional light to work by. This removal of the protecting
gauze is fraught with so much danger that miners' lamps are now made
in such a manner that the gauze is locked on to the lamp and cannot
be very easily removed by the miner.
My Invention has for its object first to increase the amount or power
of the light transmitted from the flame through the protecting medium;
second, to diminish the quantity of the combustible liquid consumed by
the wick; third, to adapt to the lamp a device for extinguishing the
flame in the event of an attempt being made to remove the gauze or
protecting medium; fourth, a device for preventing the workman from
obtaining access to the flame by perforating the protecting wire gauze.
In the accompanying Drawing I have shewn various forms or kinds
of miners or safety lamps constructed according to my Invention,

page_text: Fig. 1 is an external view and Fig. 2 a vertical section of a lamp in
which the power of the light is increased by adapting to the lamp a
convex, plano-convex, or other suitable lens, as shewn at a. This lens
may be either simple or compound, and by causing the light from the
lamp to pass through such lens its illuminating power will be greatly
increased. In order to adapt the lens to lamps already made, a part of
the wire gauze is cut away and the lens (mounted in a suitable frame)
is adapted thereto as shewn in the Drawing. A piece of tale may be
placed at the back of the lens so that in the event of the latter being
accidentally broken the external air will still be prevented from
obtaining access to the flame. A reflector b, Fig. 2, is placed behind the
flame c and throws the rays of light through the lens a in front. By
these arrangements I find by experiment that the amount of power of
the light transmitted from the flame is very greatly increased. I am
therefore enabled to reduce the size of the wick and consequently diminish
the quantity of oil or other combustible liquid consumed, and thereby
effect a considerable economy. The device for extinguishing the light
(when any attempt is made to remove the wire gauze or other protecting
medium) consists of a lever d in combination with a moveable disc or
extinguisher which will be brought down on to the wick and will
extinguish the flame upon any attempt being made to remove the wire
gauze protecting cylinder. In the present instance the reflector serves
as the extinguishing disc and is maintained in a vertical position by
means of a detent lever e, Figures 2 and 3, which is capable of being
turned on its centre as indicated by dots in Fig. 3. The lower end of
this lever extends downwards and bears against the periphery of a
ratchet for against studs made on or attached to the body of the lamp and
surrounding the wick tube. This ratchet is seen best in the plan view
Fig. 4. When the wick has been lighted and the lamp is to be prepared
for use, the disc band its lever d are held up in a vertical position
by means of the detent lever e, and when the protecting gauze and its
frame is screwed up on the lamp the tail of the detent lever e will slip
over the teeth of the ratchet wheel f, but when the lamp is unscrewed
the teeth of the ratchet will come against the tail of the detent lever c,
and will push it on one side as shown by dots in Fig. 3, so as to release
the vertical lever d which carries the extinguisher or disc b. Immedi-
ately the lever d is released the reflector or disc b will be forced down
by means of a spring i on to the wick and will extinguish the flame.
The extinguisher may be made in the form of a flat disc distinct from

page_text: the reflector or this disc may be made to act as a reflector to throw the
light through the lens as shewn in the Drawing. Or the reflector and
extinguishing disc may be separate, in which case the reflector will be
adapted to a fixed socket and therefore always remain in position, while
the extinguishing disc will be provided with the lever arrangement shown
in the Drawing.
The next improvement consists in the use of a tale cylinder which
is placed inside the wire gauze cylinder j, and will prevent the workman
from attaining access to the flame even if he perforates the wire gauze.
The lens for increasing the light and also the extinguishing device may
be adapted to the Clanny and other kinds of safety lamps as shewn at
Figures 5, 6, and 7. The brass or other metal frame which carries the
lens may either be hinged to one of the vertical rods which-surround-
the glass cylinder of the Clanny lamp or to the horizontal plates in which
the vertical rods are secured. Fig. 5 is a view of a Clanny lamp, with a
cylindrical lens (shewn detached at Fig. 5), adapted in place of the
ordinary glass cylinder. Fig. 6 is a view of a Davy lamp with a semi-
cylindrical lens adapted to the wire gauze cylinder, in which an opening
has been made to allow the light to pass through. Fig. 7 is a view of a
Davy lamp with a bulls'-eye lens mounted in a metal frame adapted
thereto. Safety lamps constructed in the manner hercin set forth may
be used in mines, collieries, underground workings, ships'. holds, powder
magazines and other places where such lamps may be required.
I would here remark that although in the Drawing I have shewn all
my separate̱ improvements combined in one lamp, so as to render the
same complete, I do not intend to confine myself to such a combination,
as either of the improvements may with advantage be used separately,
or any two in combination. For instance, if desired the extinguishing
device may be dispensed with and the lens and reflector for increasing
the light may be employed either with or without the addition of the
protecting tale cylinder with the wire gauze cylinder.
Having now described my Invention of "Improvements in the Con-
struction of Miners or Safety Lamps" and having explained the manner
of carrying the same into effect I claim as the Invention secured to me
by Letters Patent as aforesaid the adaptation to miners or safety lamps
of lenses, as herein set forth, either with or without reflectors, for the
purpose of increasing the illuminating power of the lamp and thereby
admitting of economising the combustible liquid consumed by the wick.

page_text: I also claim the use of a tale cylinder within the wire gauze cylinder for.
the purpose of preventing the light from being tampered with; I further
claim the device hercin set forth, or any mere modification thereof, for
extinguishing the flame should any attempt be made to unscrew or
remove the protecting cylinder
In witness whereof, I, the said James Allison Hogg, have hereunto
extinguishing the flame should any attempt be made to unscrew or
remove the protecting cylinder
In witness whereof, I, the said James Allison Hogg, have hereunto
set my hand and seal, the Second day of February, in the year
of our Lord One thousand eight hundred and seventy-one.
In witness whereof, I, the said James Allison Hogg, have hereunto
set my hand and seal, the Second day of February, in the year
of our Lord One thousand eight hundred and seventy-one.