IMPROVEMENTS IN THE CONSTRUCTION OF MINERS' SAFETY LAMPS
Year: 1867

page_text: LETTERS PATENT to John Rowe, of Wrexham, in the County of Denbigh,
North Wales, Civil Engineer, for the Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF MINERS' SAFETY LAMPS."
Sealed the 5th June 1868, and dated the 23rd December 1867.
PROVISIONAL SPECIFICATION left by the said John Rowe at the
Office of the Commissioners of Patents, with his Petition, on the
23rd December 1867.
I, JOHN ROWE, of Wrexham, in the County of Denbigh, North Wales,
Civil Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF MINERS' SAPETY LAMPS," to be as
follows:-
The object of my Invention is to render miners' safety lamps more secure
and durable and less liable to be opened than safety lamps of the ordinary
construction. Instead of the ordinary screw to connect the cap to the bottom
of the lamp I make a groove in the bottom and studs in the cap fitting together
in the manner of a bayonet joint, and I apply an india-rubber or other elastic
ring beneath a metal ring between the cap and bottom to form an air-tight
joint. A similar joint is applied between the flange of the wick tube and its
seating.
Another part of my Invention consists in an improved lock applicable to my
improved or to safety lamps of the ordinary construction. To the cap of the:

page_text: lamp is screwed a tube, in the outer end of which is a keyhole for the admission
of the key which takes into a recess in the end of the locking screw, and this
keyhole is so small that the screw cannot be drawn out through it. When
the lamp is locked it is impossible to unlock it with any instrument except the
proper key, which is made of a piece of steel wire with a cross pallet and with
a crank to turn it round or in any other convenient manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Rowe in the Great Seal Patent Office on the 23rd
June 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN ROWE,
of Wrexham, in the County of Denbigh, North Wales, Civil Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-tbird day of December, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirty-first year of
Her reign, did, för Herself, Her heirs and successors, give and grant unto
me, the said John Rowe, Her special license that I, the said John Rowe,
my executors, administrators, and assigns, or such others as I, the said
John Rowe, 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 IN
THE CONSTRUCTION OF MINERS' SAFETY LAMPS," upon the condition (amongst
others) that I, the said John Rowe, 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 John Rowe, 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 (that is to say) :-
:-
The object of my Invention is to render miners' safety lamps more secure
and durable and less liable to be opened than safety lamps of the ordinary

page_text: construction. Instead of the ordinary screw to connect the cap to the bottom
of the lamp I make a groove in the bottom and studs in the cap fitting
together in the manner of a bayonet joint, and I apply an india-rubber or
other elastic ring beneath a metal ring between the cap and bottom to form
an air-tight joint. A similar joint is applied between the flange of the wick
tube and its seating.
Another part of my Invention consists in an improved lock applicable to my
improved or. to safety lamps of the ordinary construction. To the cap of the
lamp is screwed a tube, in the outer end of which is a keyhole for the
admission of the key which takes into a recess in the end of the locking screw,
and this keyhole is so small that the screw cannot be drawn out through it.
When the lamp is locked it is impossible to unlock it with any instrument
except the proper key which is made of a piece of steel wire with a cross
pallet and with a crank to turn it round, or in any other convenient
manner.
And in order that my Invention may be fully understood and readily
carried into operation, I will proceed to describe the accompanying Sheet of
Drawings, reference being had to the figures and letters marked thereon.
Figure 1 is an elevation in section of a miners' safety lamp of the ordinary
construction to which my improvements are applied; Figure 2 is a plan of the
same with the cap removed; Figures 3, 4, 5, 6, and 7 are detached views of
parts of my improvements.
When the
a is the cap or top of the lamp, consisting of the ring a¹ and of the usual
frame and wire gauze; b is the bottom of the lamp containing the supply of
oil as usual. In safety lamps of the ordinary construction the ring a¹ is
screwed on to the upper part of the bottom b, but according to my improve-
ments the cap or top is connected to the bottom by studs and grooves formning
a bayonet joint in the following manner: In the ring a¹ are screwed the
two studs a², and the upper part of the bottom 6 is made with two horizontal
grooves from which are upright passages to admit the studs a².
cap or top has been placed on the bottom it is turned partly round in the
direction of the arrow in Figure 2 to bring the studs into the horizontal
grooves in the bottom until one of the studs a comes against the stop a³, as
shewn in Figure 3, thereby securing the two parts together. In order to
make a perfectly tight joint between the top and bottom parts of the lamp;
and thereby to prevent the explosive gases entering the lamp at the joint, I
make a recessed groove in the bottom b, in which groove is placed an india-
rubber or other elastic ring and a metal ring ², see Figure 4, which latter
has two little studs projecting from it, which when the ring b² is turned partly

page_text: round, enter in the recess, and thus secure the rings 61 and 62 in their places.
The lower part of the ring a¹ presses upon the ring b² when the top and
bottom parts of the lamp are together.
The wick tube c is made with a flange c' as usual, but instead of securing
this flange by a screwed cap as heretofore I secure it by a bayonet joint in the
following manner:-In the centre of the bottom 6 is a recessed groove con-
taining the india-rubber or other elastic ring d and the metal ring d¹ which
has two projecting studs, as shewn in Figure 5, to hold the rings d and d¹ in
their places. The cap e is also made with two studs fitting in horizontal
grooves in the bottom b, and these grooves have passages for the admission of
the studs. The lower end of the cape is pressed upon the flange of the wick
tube c, and when the cap e is turned partly round the wick tube is held
securely in its place. By this means the stripping of the screws which so soon
takes place in ordinary safety lamps is avoided.)
My improved locks which are applicable to ordinary safety lamps as well as
to those constructed according to my present improvements are made in the
following manner:-To the ring a¹ is screwed the tube f; this tube is screwed
internally with, by preference, a left-handed thread, but a right-handed one
may be used, and the outer end of the tube f is provided with the keyhole for
the locking key. The locking screw f¹, see Figure 6, is screwed into the
tube f, and the inner end of this locking screw which is made of hardened steel
fits into a recess in the bottom 6 as usual. The locking screw f¹ is provided
with a loose spindle f* which is connected to the screw f¹ by a pin fitting in a
groove in the spindle, and the outer end of the screw f¹ is provided with four
or other suitable number of wards for the locking key shewn in Figure 7.
This key consists of a hardened steel barrel g with pallets at its end corre-
sponding to the wards in the screw f¹, the barrel 9 being fixed into the
handle g¹ by a tightening-up nut g, the object of which is to facilitate repairs
when the pallets of the barrel are worn away or broken. By thus making the
locks of safety lamps it is impossible for the miners to draw the locking
of the tube f is smaller than
screw fout because the hole in the outer end
the screw, and from the peculiar shape of the wards in the locking screw and
of the locking key, and from the spindle få being loose and partially closing
the keyhole it is not possible for the miners to pick the lock. When the
lamp is locked the lock is closed by the lid which is connected to the cap by
a chain; this lid prevents dirt or dust from entering the keyhole. The wire i
shewn in Figure 1 is for trimming the wick as usual.
Having thus stated the nature of my Invention, and described the manner
of performing the same as applied to an ordinary Davy safety lamp, I wish it

page_text: to be understood that my improvements are equally applicable to the various
safety lamps known as the "Claney," the "Stephenson," and others. I claim
as my Invention and when used either separately or collectively,-
First. Connecting the cap or top of safety lamps to the bottom part by a
bayonet joint, as described and shewn.
Secondly. Connecting the wick tube of safety lamps to the bottom part by a
bayonet joint as described and shewn.
Thirdly. The improved mode of making the joint between the top and
bottom parts of safety lamps and between the flange of the wick tube and the
bottom, as shewn and described.
And, lastly. The improved locks for miners' safety lamps, as shewn and
described, and particularly making the keyhole smaller than the locking screw,
for the purpose described.
In witness whereof, I, the said John Rowe, have hereto set my hand
and seal, this Twenty-second day of June, One thousand eight hundred
and sixty-eight.