IMPROVEMENTS IN MINERS' SAFETY LAMPS
Year: 1868

page_text: LETTERS PATENT to Thomas Story Horn, of No. 23, Grove Street,
in the Borough and County of Newcastle-upon-Tyne, Agent, for
the Invention of " IMPROVEMENTS IN MINERS' SAFETY LAMPS."
Sealed the 24th November 1868, and dated the 28th May 1868.
PROVISIONAL SPECIFICATION left by the said Thomas Story Horn
at the Office of the Commissioners of Patents, with his Petition,
on the 28th May 1868.
I, THOMAS STORY HORN, of No. 23, Grove Street, in the Borough.
and County of Newcastle-upon-Tyne, Agent, do hereby declare the nature
of my said Invention for "IMPROVEMENTS IN MINERS' SAFETY LAMPS," to
be as follows:-
This Invention relates to a means of obtaining an increased amount
of light and more perfect combustion in miners' safety lamps than has
hitherto been obtained whereby little or no unconsumed carbon or soot
is deposited in or upon the lamp, and the lamp is rendered moreover
thoroughly unexplosive, and the light is immediately extinguished
should the lamp by accident or otherwise be overturned.

page_text: This Invention has reference also to an improved lock for fastening
all the parts of the improved lamp together.
In constructing a safety lamp according to this Invention the base of
the lamp forms the receptacle for the oil, having a tube in the centre for
the insertion of the wick or lamp cotton and for feeding or supplying
the lamp with oil. Above this receptacle and permanently attached to
it there is an air chamber perforated round the circumference for the
admission of air horizontally at a point below the point of combustion.
The top plate of this air chamber is also perforated with very fine holes
for the admission of the air to a combustion chamber which surrounds
the wick and is formed of metal of a dome or other shape, having an
aperture at the summit through which the wick can pass. This metal
dome is fitted by a bayonet joint screw or other means into a metal ring
or flange, which flange has formed on its outer or upper surface an
annular groove for the reception of a glass chimney, which is cemented
therein. By the use of the dome the air for supporting combustion
passing through the air chamber from below impinges on the flame at
the point of combustion, rendering such combustion more complete
and therefore affording increased light. The dome also acts as an
extinguisher should the lamp be either overturned by accident or
otherwise, the light in that case immediately dying out. The products
of combustion pass up the glass chimney through a contracted aperture
in a metal cone fitted thereon, and becomes diffused by escaping through
small perforations in a copper cap fitting on the glass chimney. This
cap and also the dome may be readily removed when necessary for the
purpose of cleaning the glass chimney. A guard of metal or other
suitable material may if desired surround the apertures in the circum-
ference of the air chamber and serve as a protection against any sudden
gust, blow, or outburst of gas or air interfering with the steadiness of
the light. In some cases the air for supplying combustion is admitted
through perforations in the metal guard which is attached to the base
of the lamp by a screw; to this guard is also screwed a metal chamber,
the top of which is formed of perforated metal or wire gauze; the
circumference is also perforated and a layer of wire gauze is placed
over the perforations. This chamber is also made to fit tightly round
the central tube used for feeding the lamp with oil.
On the upper
and outer circumference of this chamber there is run a groove into
which the glass chimney is cemented; this glass chimney is protected
by being surrounded with wire gauze firmly fixed to an air chamber by

page_text: the guard gripping it. On the top of the glass chimney I place a double
cap of copper, the inner one being perforated at the sides and top,
whilst the outer one is only perforated at the top. As a protection to
the glass chimney from breakage a wire cage is placed on the exterior
so as to surround the same. With a view to locking the lamp there is
drilled in the top rim and bottom flange an aperture which extends also
into the solid part of the side of the air chamber, the drilling being of
course in a line so as to admit of a steel rod passing through from top
to bottom. On the top rim there is rivetted a metal tongue, which is
bored to admit of a screw bolt, and on the top cover there is rivetted
another and larger piece of metal having a slit for the passage of the
former piece, this larger piece being also bored partially through for
the passage of the said screw bolt. This bolt is so fixed as not to be
capable of entire withdrawal. On bringing the cover down the metal
tongue enters the lock on the cover, and the bolt is then screwed by a
key through both picces, thereby locking the lamp. The cover by
covering the head of the steel rod keeps it in place, and the lower end
of the steel rod by passing through the lower flange into the solid piece
below prevents the base from being unscrewed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Story Horn in the Great Seal Patent
Office on the 28th November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
STORY HORN, of Number 23, Grove Street, in the Borough and
County of Newcastle-upon-Tyne, Agent, send greeting. "
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of May, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Story Horn, Her special license
that I, the said Thomas Story Horn, my executors, administrators, and
assigns, or such others as I, the said Thomas Story Horn, my executors,
administrators, or 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,

page_text: within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN SAFETY
LAMPS," upon the condition (amongst others) that I, the said Thomas
Story Horn, my executors or administrators, by an instrument in writing
under my hand and seal, 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 Scal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Story Horn, 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 accompanying Drawings,
and to the letters and figures marked thereon, that is to say :-
My said Invention relates to a means of obtaining an increased
amount of light and more perfect combustion in miners' safety
lamps than has hitherto been obtained whereby little or unconsumed
carbon or soot is deposited in or upon the lamp, and the lamp is
rendered moreover thoroughly inexplosive, whilst the light is imme-
diately extinguished should the lamp by accident or otherwise be
overturned.
My said Invention has reference also to an improved lock for
fastening all the parts of the improved lamp together.
In constructing a safety lamp according to my Invention the base
of the lamp forms the receptacle for the oil, having a tube in the
centre for the insertion of the wick or lamp cotton and for feeding
or supplying the lamp with oil. Above this receptacle and attached
to it there is an air chamber perforated round the circumference or
surrounded with wire gauze for the admission of air horizontally at
a point below the point of combustion. The top plate of this air
chamber is also perforated with very fine holes for the admission of
the air to a combustion chamber which surrounds the wick and is
formed of metal of a dome or other shape, having an aperture at the
summit through which the wick can pass. This metal dome is fitted
by a bayonet joint screw or other means into a metal ring or flange,
which flange has formed on its outer or upper surface an annular
groove for the reception of a glass chimney which is cemented therein.
By the use of the dome the air for supporting combustion passing

page_text: through the air chamber from below impinges on the flame at the
point of combustion, rendering such combustion more complete and
therefore affording increased light. This dome also acts as an
extinguisher should the lamp be overturned by accident or otherwise,
as the light in that case will immediately die out. The products of
combustion pass up the glass chimney through a contracted aperture
in a metal cone fitted thereon, and become diffused by escaping through
small perforations in the copper caps fitting on to the glass chimney
and enclosing the cone. This cap and also the cone may be readily
removed when necessary for the purpose of cleaning the glass chimney.
A guard of perforated metal or other suitable material may if desired
surround the apertures in the circumference of the air chamber and
serve as a protection against any sudden gust, "blow," or outburst
of gas or air interfering with the steadiness of the light. As a pro-
tection to the glass chimney a cage of wire gauze is sometimes placed
on the exterior so as to surround the same. With a view to locking
the lamp there is drilled in the top rim and bottom flange an aperture,
which extends also into the solid part of the base, the drilling being of
course in a line, so as to admit of a steel rod passing through from top
to bottom. On the top rim there is rivetted a metal tongue which is
bored to admit of a screw bolt, and on the top cover there is rivetted
another and larger piece of metal having a slit for the passage of the
former piece, this larger piece being also bored partially through for
the passage of the said screw bolt, which is oval at the end, for the
reception of the key. This bolt should be so fixed as not to be capable
of entire withdrawal. On bringing the cover down the metal tongue
enters the lock on the cover, and the bolt is then screwed by a key
through both pieces, thereby locking the lamp; the cover by covering
the head of the steel rod keeps it in place, and the lower end of the
steel rod by passing through the lower flange into the solid piece
below prevents the base from being unscrewed.
And in order that my said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings, the
same letters of reference indicating corresponding parts in all the
Figures.
Figure 1 of my Drawings represents a side elevation and partial
section of one modification of my improved safety lamp; Figure 2 is

page_text: a vertical section of a larger sized lamp slightly varied from Figure 1;
and Figure 3 is a sectional detail of the locking arrangement shown
in Figure 1.
In these Figures A is the oil reservoir and base of the lamp provided
with a tube B in the centre for the reception of the wick or cotton, as
shown in Figure 2, and for replenishing the reservoir with oil; C is
the air chamber screwed at a to the top of the oil reservoir. The top
plate 6 of the air chamber is finely perforated, and the circumference
of such chamber is composed of wire gauze c. D is the combustion
chamber surrounding the wick, the top of such chamber being formed
by the removeable metal dome E with a central aperture for the passage
of the wick. A bayonet or other suitable joint serves to connect the
dome E with the ring or flange F, such flange having an annular
dovetail groove d on its upper surface for the reception of the lower
edge of the glass chimney G, which is permanently cemented therein,
a bead or groove being made round the top and bottom of the glass
chimney in order to form a more secure hold for the cement. The ring
or flange is screwed into the outer ring H which forms the upper
This
portion of the base of the lamp, being screwed thereon at e, e.
ring His perforated circumferentially, as shewn at ff (Figure 2), in
order to admit air horizontally into the air chamber C. With a view
to protect the air chamber from any sudden gust, "blow," or outburst
of gas or air an outer perforated guard I of an annular form may be
applied round the perforations f,f. This guard may either be made
solid with the ring H, as shown in Figure 1, where a series of perfora-
tions g, g', are shown both at the top and bottom, the perforations f
being dispensed with, or it may be a separate loose attachment with
perforations at the bottom only, as shown in Figure 2, in which latter
case it can be fixed in position by one or more screws if desired, as
will be readily understood. The products of combustion pass up the
glass chimney G through the contracted aperture 1 in the metal cone K,
which is fitted onto the top of such chimney. This cone is enclosed
in a double cap of copper, the inner one I being perforated at the sides
and top, whilst the outer one M is only perforated at the top. The
cone and caps can be readily removed for the purposes of cleaning or
repairs. I sometimes surround the glass chimney with a cylindrical
wire gauze cage N, as shown in Figure 2, as a protection against
breakage, but if not found requisite this wire gauze protection may be

page_text: dispensed with, as shown in Figure 1. When using the wire gauze
I secure it in place by nipping its lower edge between the ring or
flange F and the part H, as is clearly shown in Figure 2, the various
joints in the lamp being made sufficiently tight to exclude all air
excepting that which passes through the air chamber C, so that should
the gauze N be taken out the lamp will remain as safe as before.
My improved mode of locking the lamp is shown in Figure 1, and
consists of two holes which are respectively drilled in the top rim O and
bottom flange, the last-mentioned hole being continued, as shown at i,
into the metal of the base A of the lamp. P is a sliding steel rod
held upwards when left free by a helical spring k, such rod when
forced down entering like a bolt into the recess or spring i, and thereby
effectually preventing the base from being unscrewed. This rod is held
down by the hinged cover Q of the lamp (shewn turned back in
Figure 1), such cover pressing upon the top of the rod P when closed
and keeping it in its locked position. The cover is locked when shut
down by means of a concealed screw (shown in the sectional detail,
Figure 3) having an oval-shaped head which fits a correspondingly
shaped key. This screw is contained within a piece of metal m fast
on the cover, such piece of metal having a slit or opening therein for
the entrance of a metal tongue n on the rim O. A hole is made
transversely through the metal tongue n, and when the parts are in
their closed positions the screw is turned by a key for that purpose,
so as to cause it to pass through the hole in the tongue, thus locking
the cover down and maintaining the lower end of the rod P in the
aperture in the base of the lamp. A small plate serves to prevent the
entire withdrawal of the screw from the lamp, but so soon as the end
of the screw is withdrawn from the tongue the spring / forces upwards
the rod P, and leaves the basc A free to be unscrewed or detached.
A small pin p in the rod P prevents it from rising too high. I prefer
to place the lock at the base when using a gauze protector, as shewn
in Figure 2, the concealed screw having an oval-shaped head entering
direct into a hole or recess in the side of the base.
In this arrange-
ment of lock the top or cover Q will be permanently fixed to the
rim.
Having now described and particularly ascertained the nature of
my said Invention, and the manner in which the same is or may be used
or carried into effect, I would observe in conclusion that what I

page_text: consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent
is, —
-
First. The general construction and arrangement of miners' safety
lamps, substantially as herein-before described and illustrated by my
Drawings.
Second. The application and use to and in miners' safety lamps of
a perforated air chamber fixed below the point of combustion of the
wick and surrounding the wick tube, through which air chamber the
whole of the air for supporting combustion must pass on its way to the
flame, substantially as herein-before described.
Third. The combination with a perforated air chamber of a combustion
chamber which surrounds the wick, substantially as and for the purpose
herein-before described.
Fourth. The application and use to and in miners' safety lamps of a
dome placed above the point of combustion of the wick, and provided
with a central aperture for the passage of the flame, substantially as and
for the purpose herein-before described.
Fifth. The application of a cone or contracted aperture to the upper
end of the glass chimney of a miner's safety lamp, and the enclosing
of such cone within a perforated metal cap or caps, substantially as
herein-before described.
Sixth. The peculiar mode of locking miners' safety lamps by a sliding
rod pressed down into a recess or hole in the base by the top or cover,
substantially as herein-before described.
In witness whereof, I, the said Thomas Story Horn, have to this
my Specification set my hand and seal, the Twenty-fifth day
of November One thousand eight hundred and sixty-eight.
THOMAS STORY HORN. (L.S.)