IM- PROVEMENTS IN MINERS' SAFETY-LAMPS
Year: 1879

page_text: LETTERS PATENT to John Davenport Shakespear, late Colonel Royal Artillery,
J.P., of Barons' Court, in the County of Middlesex, for the Invention of "IM-
PROVEMENTS IN MINERS' SAFETY-LAMPS."
Sealed the 28th October 1879, and dated the 8th May 1879.
PROVISIONAL SPECIFICATION left by the said John Davenport Shakespear
at the Office of the Commissioners of Patents on the 8th May 1879.
"
JOHN DAVENPORT SHAKESPEAR, late Colonel Royal Artillery, J.P., of Barons'
Court, in the County of Middlesex. IMPROVEMENTS IN MINERS' SAFETY LAMPS."
My Invention consists in improvements in miners' safety lamps, and refers to all
types of miners' safety lamps, but more especially to the type known as the Clanny
lamp.
The chief object of my Invention is to provide against "blowing through," a
common danger with other lamps in fiery mines, and to render such "blowing
through" practically impossible.
Its object is also to provide means for lowering the light or lessening the flame
in order to ascertain if there is any gas burning within the combustion chamber of
the lamp, or for extinguishing the light as the lamp is opened; and further to
simplify the method of opening and closing such safety lamps by avoiding the use
of screws, bolts, and springs.
Having explained the nature and object of my Invention, I will now proceed to
describe the manner in which the said improvements are effected.
In order to prevent "blowing through" I use in place of the ordinary single
wire gauze chimney an inner chimney and an outer chimney, having a space of
from an eighth to half an inch between them. These chimneys may be made either
of iron wire gauze or copper wire gauze, but I prefer to use copper on account of
its being a better conductor of heat. The inner chimney has a large flange of wire
gauze at its lower end, which separates the space between the two chimneys from
the combustion chamber, and the gas entering the lamp burns only within the
combustion chamber and inner chimney, while the outer chimney prevents the gas
outside the lamp from being ignited by "blowing through."
The combustion chamber is fitted close against the flanges of the chimneys, and
is held in its place by means of a plate screwed into the frame of the lamp. Between

page_text: this plate and the combustion chamber I place a washer of some pliant but unin-
flaminable material, such as asbestos, but when I wish to make the lamp moro
sensitive to the gas in the mine I use a washer of wire gauze instead thereof.
To avoid the use of screws, bolts, & springs, in the arrangement for lowering or
extinguishing the light, and in order to simplify the opening and closing of the
lamp I use an extinguisher, consisting of a tube having a long ring of cork or other
suitable material round the lower part of it. This extinguisher fits loosely over
the burner or wick tube. The lamp has two or more snugs or studs on it which
fit into inclined slots in the frame.
To close the lamp it is pushed up into the frame and the studs entered into the
slots, and then by giving it a quarter of a turn the lamp is at once fastened to the
frame, and an ordinary screw lock is used if necessary to add more security, and to
prevent the lamp from being opened without the use of a key. This action of
closing the lamp presses the ring of cork into a tube connected to the plate at the
bottom of the combustion chamber, where it is retained, together with the ex-
tinguisher, and if it is required to lower the light or lessen the flame the lamp is
turned partly back so as to bring the studs down the slots, thereby drawing the
burner or wick tube down inside the extinguisher, by doing which the size of the
flame is gradually reduced, but stops are fitted so that the light should not be put
out unintentionally without the lamp being unlocked and withdrawn from the
flame. It is impossible to open the lamp after it has been once closed without
drawing the burner or wick tube down through the extinguisher, thus putting out
the light.
The lamp contains an absorbent like the ordinary benzine lamp, and is filled
through an inerted syphon tube fitted into it in order to prevent any oil not
absorbed from being spilt.
In altering old screwed lamps in accordance with my Invention the screw may
be cut into segments in order to obviate the necessity of giving the lamp several
turns to open or close it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Davenport Shakespear in the Great Seal Patent Office on the
8th November 1879.
JOHN DAVENPORT SHAKESPEAR, late Colonel Royal Artillery, J.P., of Barons'
Court, in the County of Middlesex. "IMPROVEMENTS IN MINERS' SAFETY-LAMPS."
This Invention relates to improvements in miners' safety lamps.
One object of my Invention is to prevent "blowing through," that is, the com-
munication (through the gauze chimney of the lamp) of the flame of any burning
gas within the combustion chamber to any inflammable gases surrounding the
lamp outwardly. This is a common danger in fiery mines with lamps at present
in use.
Another object is to improve and simplify the means of rendering it impossible in
such lamps to withdraw, or in any way get at the light. Opening the lamp must
extinguish the flame, but at the same time the flame may be gradually lowered to
the minimum without being extinguished, and so enable the detection of any gas
burning within the combustion chamber, as such burning gas may be best seen
when the flame is well lowered.
I will now proceed to fully describe my Invention with the aid of the accom-
panying Drawings, in which Fig. 1 is an elevation of a lamp constructed according
to my improvements; Fig. 2, a sectional elevation, but with the lamp J shewn in
full; and Figs. 3 to 8 views of details. The same letter of reference indicates like
parts in all the several Figures.
In order to prevent the "blowing through "I employ in place of the single wire
gauze chimney two such chimneys A, B, one within the other concentrically (as
seen clearly at Fig. 2). These may be made of either iron or copper wire gauze,
but I prefer the latter. The annular space between them, and also between their
tops, may vary from an eighth to half an inch, and this space is completely isolated
from the combustion chamber, excepting so far as the apertures of the wire gauze
of the inner chimney allow of communication. This isolation is effected as
follows:-The outer chimney covered in at the top fits at its lower end closely
around the outer circumference of a cylinder C, which with the flange C¹ & C² form
a portion of the framework of the lamp. The inner chimney B, also covered in at
the top, bas surrounding its lower end a flange B¹, which is pressed tightly against
flange C of frame by glass combustion chamber D. This glass I prefer of the
form shewn, though a cylindrical or other suitable form of glass may be used if
desired. This glass is in its turn pressed firmly against gauze flanges B₁ by plate E
(shewn detached in sectional elevation and plan at Figs. 5 & 6 respectively) screwed
into body F of lamp framing. Between the glass D and plate E is a washer I of
any suitable yielding uninflammable material, such as asbestos. When I desire to
make the lamp particularly sensitive to the fiery gas in the mine I use wire gauze
for this washer. Body F, intermediate part of frame C, C1, C2, and top of lamp
frame G, are united as shewn by their rods H. Thus constructed the combustion
chamber is completely and entirely isolated from the space between the two gauze
chimneys (except for the apertures in the wire gauze), and there are always two
layers of gauze between the frame of the lamp and the outer atmosphere. This
construction of lamp will be found to prevent any flame within the combustion
chamber being communicated to inflammable gases surrounding the lamp
outwardly.
The second part of my Invention I accomplish as follows:-The plate E is
furnished concentrically with an uprising flange E¹ (cylindrical or nearly so)
for use as hereinafter described; J is the lamp, and Ji the wick tube. These
are shewn in elevation and plan at Figs. 3 and 4 respectively, surrounding
the wick tube, and fitting same closely but loosely is an extinguisher K, shewn
in plan and sectional elevation at Figs. 7 & 8 respectively. This extinguisher

page_text: is made to fit tightly flange E¹ when pressed into same. The action is as follows:-
The extinguisher K is first dropped over the wick tube J¹ when the lamp J is
lighted; the lighted lamp, together with the extinguisher, are then passed upwards
into the body of the lamp framing, and the lamp is screwed into position as seen
to Figs. 1 and 2. By this means the extinguisher is forced up into the flange E¹ in
fhich it is firmly held by reason of their tightness of fitting, or in other words, the
diction between them; on the lamp being unscrewed to open it the wick is drawn
own through the extinguisher, bearing the latter behind firmly held in flange E¹. The
flame in thus slowly passing through the extinguisher is put out. By no means can
the extinguisher be drawn out with the lamp, and consequently the lamp cannot
possibly be opened without the light being extinguished. The friction between the
extinguisher K and flange E¹ may be induced in various ways. As illustrated in
the accompanying Drawings the extinguisher is surrounded by a coating of cork K¹,
which I find to answer the purpose well. Instead of the cork india rubber or any
other suitable elastic material may be employed; or the extinguisher may be
formed as a split ring (metal or otherwise) fitting flange E¹ tightly, or any other
suitable method of inducing the necessary friction may be employed.
I claim as my Invention,-
1. The use of two gauze chimneys A, B, substantially as and for the purpose
described and illustrated.
2. Extinguisher K; also same in combination with flange E¹, lamp J, and wick
tube J, substantially as and for the purpose described and illustrated.
3. Glass D in combination with gauze flange B¹ and gauze washer I, substantially
as and for the purpose described and illustrated.
In witness whereof, I, the said John Davenport Shakespear, have hereunto set
my hand and seal, this 8th day of November, in the year of our Lord One
thousand eight hundred and seventy nine.
J. D. SHAKESPEAR. (L.S.)