Im- PROVEMENTS IN MINERS' SAFETY LAMPS
Year: 1864

page_text: LETTERS PATENT to Frederick Foster, of No. 11, Salisbury Street, New
North Road, in the County of Middlesex, for the Invention of "Im-
PROVEMENTS IN MINERS' SAFETY LAMPS."
Sealed the 31st May 1864, and dated the 11th March 1864.
PROVISIONAL SPECIFICATION left by the said Frederick Foster at the
Office of the Commissioners of Patents, with his Petition, on the 11th.
March 1864.
I, FREDERICK FOSTER, of No. 11, Salisbury Street, New North Road, in
the County of Middlesex, do hereby declare the nature of the Invention
for "IMPROVEMENTS IN MINERS' SAFETY LAMPS," to be as follows:- ·
This Invention applies to miners' safety lamps when so constructed that
they cannot be opened whilst in use without lowering the wick and ex-
tinguishing the flame. To accomplish this end much more conveniently than
it has been attained in safety lamps heretofore constructed, I proceed as
follows-I cause the ring or frame of the wire gauze when it is put into its
place to engage with a disc or instrument which when turned raises and
lowers the wick, and on the gauze frame I put a spring catch, which when
the locking ring is screwed into its place bears against the interior thereof,
and there is a stop on the locking ring which will allow the spring catch to
pass it in one direction only. Without this catch the wire gauze could be
turned freely round in either direction, and the wick could be thus turned up
or down to any extent without opening the lamp, but the spring catch limits

page_text: this motion so that the gauze can be turned to raise the wick only so far as
to bring the catch up to the stop on the locking ring, a distance which is
made sufficient for turning up the wick to such an extent as can be required
In opening the lamp, however, the locking ring requires perhaps
several turns to free its screw, and in the course of this motion immediately
the spring catch is brought up to the stop on the locking ring, the gauze is
compelled to turn with the locking ring, and the motion so communicated to
it lowers the wick and extinguishes the flame. The wick I employ is an
ordinary tubular wick, it fits on to a wick holder or thimble, capable of
sliding up and down a standard or tube fixed in the centre of the oil vessel.
This standard or tube has a spiral groove cut around it, and a pin on the
wick holder or thimble enters this groove. A pin also projects from the
exterior of the wick holder or thimble, and enters a slit in a tube which
surrounds the standard in the centre of the oil vessel, passing loosely over the
wick holder or thimble thereon. On the split tube a disc is fixed, having on
its periphery holes perforated, and into one of these holes a pin on the frame
of the wire gauze enters when the gauze is put into its place, so that when
the gauze is turned round the disc must go with it, and so raise or lower the
wick. If desired a solid wick may be employed in place of a tubular wick,
the wick then passing within the central tube or standard of the oil vessel,
and the raising and lowering apparatus being somewhat modified.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick Foster in the Great Seal Patent Office on the
10th September 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK 2
FOSTER, of No. 11, Salisbury Street, New North Road, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of March, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-seventh year of 8
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Frederick Foster, Her special licence that I, the said Frederick Foster,
my executors, administrators, and assigns, or such others as I, the said
Frederick Foster, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter 8
during the term therein expressed, should and lawfully might make, use,

page_text: exercise, and vend,. within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
MINERS SAFETY LAMPS," upon the condition (amongst others) that I, the said
Frederick Foster, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 Frederick Foster, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
This Invention applies to miners' safety lamps when so constructed that
they cannot be opened whilst in use without lowering the wick and ex-
tinguishing the flame. To accomplish this end much more conveniently than
it has been attained in safety lamps heretofore constructed, I proceed as
follows: I cause the ring or frame of the wire gauze when it is put into its.
place to engage with a disc or instrument which when turned raises and
lowers the wick, and on the gauze frame I put a spring catch, which, when
the locking ring is screwed into its place, bears against the interior thereof,
and there is a stop on the locking ring which will allow the spring catch to
pass it in one direction only. Without this catch the wire gauze could be
turned freely round in either direction, and the wick could be thus turned up
or down to any extent without opening the lamp, but the spring catch limits
this motion, so that the gauze can be turned to raise the wick only so far as
to bring the catch up to the stop on the locking ring, a distance which is
made sufficient for turning up the wick to such an extent as can be required
in use.
In opening the lamp, however, the locking ring requires perhaps
several turns to free its screw, and in the course of this motion immediately
the spring catch is brought up to the stop on the locking ring the gauze is
compelled to turn with the locking ring, and the motion so communicated to
it lowers the wick and extinguishes the flame. The wick I employ is an
ordinary tubular wick, it fits on to a wick holder or thimble capable of sliding
up and down a standard or tube fixed in the centre of the oil vessel. This
standard or tube has a spiral groove cut around it, and a pin on the wick
holder or thimble enters this groove. A pin also projects from the exterior
of the wick holder or thimble, and enters a slit in a tube which surrounds
the standard in the centre of the oil vessel, passing loosely over the wick

page_text: holder or thimble thereon. On the split tube a disc is fixed, having on its
periphery holes perforated, and into one of these holes a pin on the frame of
the wire gauze enters when the gauze is put into its place, so that when the
gauze is turned round the disc must go with it, and so raise or lower the
wick. If desired a solid wick may be employed in place of a tubular wick,
the wick then passing within the central tube or standard of the oil vessel,
and the raising and lowering apparatus being somewhat modified.
Having thus stated the nature of my Invention, I will proceed more fully
to describe the manner of performing the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shews a vertical section of a miners' safety lamp constructed and
combined according to my Invention; Figure 2 shews an under sido view and
section of the ring by which the cylinder of wire gauze is attached and
secured to the oil vessel; Figure 3 shews a plan and section of the ring
which is fixed to the lower end of the wire gauze cylinder; Figure 4 shews
a plan and section of the outer tube, between which and the fixed inner tube
or standard the wick is received. In this outer tube there is a vertical slit,
whilst in the fixed or standard tube there is a spiral groove in the ordinary
manner, so that the wick is raised and lowered by the rotation of the outer
tube shewn at Figure 4 in like manner to what has heretofore been the
practice in argand burners.
a is the oil vessel having the central or standard tube b, up which air to
support combustion passes. Below the bottom of the oil vessel is an air
chamber formed by the cylinder c, which screws on to the lower part of the
oil vessel. At the sides of this cylinder are holes c¹, c, through which air
Blows into the chamber below the oil vessel. These holes are covered by two
thicknesses of wire gauze fixed on either side of a ring c², in the sides of which
are holes corresponding with the holes in the sides of the cylinder c, hence
air can get into the chamber below the oil vessel, but the gauze prevents
anything being introduced into the chamber or into the wick tube, and con-
sequently no light can be obtained in this direction. The cylinder c is
secured from being removed by a bolt introduced through the tube c
formed through the oil vessel, and the bolt is prevented being raised so long
as the wire gauze cylinder d is in its place; is an instrument such as has
heretofore been used for trimming the upper part of the wick. The lower
end of the ordinary wire gauze cylinder d is securely fixed on to the ring d¹.
This ring d¹ has a stud or projection d' which enters one of the holes f¹, f', in
the disc fixed on the outer tube f, consequently the cylinder of wire gauze d

page_text: cannot be turned without also turning the tube f, which, as before explained,
cannot be turned without causing the wick to be raised or lowered, and the
arrangement is such that by turning the cylinder d of wire gauze with a view
to separate such cylinder from the oil vessel, the wick shall be caused to
descend, and the light be extinguished before the ring 9, shewn separately at
Figure 2, is unscrewed from the oil vessel. The ring of fits into the ring g,
but it (with the cylinder of wire gauze fixed thereto) is at liberty to turn
independently of the ring g for a certain distance, in order that the outer tube
may be turned to such an extent as to raise the wick a quantity sufficient to
enable a lamp to be used the required time without separating the wire
gauze cylinder d from the oil vessel. The ring f is thus at liberty to turn
within the ring g by means of the spring stud d³, which, when it comes to the
stop g¹ within the ring g, prevents the ring f and wire gauze cylinder & being
turned further without at the same time turning the ring 9, by which not only
will the ring g be unscrewed from the oil vessel, but the wick will be caused
to descend and the light be put out. It is preferred to employ argand
burners, but it will be evident that lamps may be constructed with solid
wicks, the mode of raising and lowering them being modified accordingly.
Having thus described the nature of my Invention, and the manner of
performing the same, I would have it understood that I make no claim to any
of the mechanical parts separately, but what I claim is, the combined
arrangement herein described for securing the wire gauze cylinder to the oil
vessel.
In witness whereof, I, the said Frederick Foster, have hereunto set my
hand and seal, this Ninth day of September, in the year of our
Lord One thousand eight hundred and sixty-four.
FRED. FOSTER. (L.S.)