AN IMPROVED SAFETY LAMP FOR MINING PURPOSES
Year: 1869

page_text: LETTERS PATENT to John Hyde, of West Bromwich, in the County
of Stafford, Engineer, and Joseph Hyde, of Warwick, in the County
of Warwick, Engineer, for the Invention of "AN IMPROVED SAFETY
LAMP FOR MINING PURPOSES."
Sealed the 21st January 1870, and dated the 26th July 1869.
PROVISIONAL SPECIFICATION left by the said John Hyde and Joseph
Hyde at the Office of the Commissioners of Patents, with their
Petition, on the 26th July 1869.
We, JOHN HYDE, of West Bromwich, in the County of Stafford,
Engineer, and JOSEPH HYDE, of Warwick, in the County of Warwick,
Engineer, do hereby declare the nature of the said Invention for "AN
IMPROVED SAFETY LAMP FOR MINING PURPOSES," to be as follows:-
The object of this Invention is by the means herein-after explained
to prevent explosions in collieries which are now of such frequer
occurrence.

page_text: The improved safety lamp we propose to use for this purpose is
constructed substantially as follows:-A bed plate of suitable size being
provided there are two holes tapped therein, one of which is to receive
the oil lamp, and the other a metal stand through which goes a hooked
stalk, to which is attached the lower end of the strip of lead (or other
fusible material) herein-after mentioned. To the upper end of this strip
of lead is attached the upper end of a metal leg provided with a hooked
top, the lower end of the leg being screwed into the metal stand
herein-before mentioned. Upon the top of the said metal stand wire
gauze is placed, such as is used in the ordinary Davy lamp, and which
as will be understood encloses the oil lamp and the metal stand berein-
before referred to, and is fastened to the bed plate by caps and pins or
by any other suitable means. Outside the gauze there is a metal box
having four sides, and which is closed upon its top and two ends, but on
both of its two sides there are two spaces, which will be open and un-
covered when the apparatus is in its normal condition, but which when
required are closed by gridiron valves. These gridiron valves are made
to rise and fall, and it should be explained that a link is connected to
the top of each valve, which comes down and works into a double lever
working on centres at the end of the box about half way down. To this
double lever is connected a bridle which goes down to the under side of
the bed plate, so that when the valves are raised the bridle will rest on
the bottom end of the stalk which goes through the centre of the metal
stand herein-before referred to, and which at its upper end it will be
remembered is suspended to the strip of lead herein-before referred to.
The box is secured upon the bed plate by pins at each corner, or in
any other suitable manner.
The operation of the apparatus or safety lamp is as follows:-The
lamp is suspended from the top of the roof and is placed near to it, and
the tendency of foul air being upwards it will of necessity act upon the
lamp before affecting the lower atmosphere, and so soon as the foul air
enters the gauze it becomes ignited, the strip of lead (or other fusible
material) before mentioned which is used to suspend the stalk is quickly
melted, when the stalk immediately drops, the valves also fall, and the
lamp thus becomes extinguished from want of combustion. The shaft
of the double lever before spoken of is fitted with a stop which holds the
hammer of an alarum or striking movement. This is its normal state,
but when the stalk drops in the manner just mentioned the said

page_text: hammer by the same movement becomes free from its stop, and the
alarum gives an alarm that firedamp is in the pit and that the lamp
has become extinguished. Thus any accident of a series nature may be
entirely prevented.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Hyde and Joseph Hyde in the Great Seal
Patent Office on the 26th January 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, wе, JOHN
HYDE, of West Bromwich, in the County of Stafford, Engineer, and
JOSEPH HYDE, of Warwick, in the County of Warwick, Engineer, send
greeting,
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of July, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said John Hyde and Joseph Hyde, Her.
special licence that we, the said John Hyde and Joseph Hyde, our
executors, administrators, and assigns, or such others as we, the said
John Hyde and Joseph Hyde, our 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 "AN IMPROVED SAFETY LAMP FOR MINING PURPOSES," upon the condition
(amongst others) that we, the said John Hyde and Joseph Hyde, our
executors or administrators, by an instrument in writing under our, 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 we, the said John Hyde and Joseph Hyde,

page_text: the same is to be performed, to be particularly described and ascertained
in and by the following statement (that is to say)
In the Provisional Specification filed by us six months since the
object of our Invention was fully explained and a general description
of the nature of the Invention sought to be secured was given. During
the interval which has since clasped it has been our desire to simplify
as much as practicable the apparatus by which we carry our Invention
into effect, for it will be understood that we do not desire to claim the
precise arrangement of parts set forth as constituting the apparatus by
which our Invention is carried into effect, but a lamp in which a fusible
link may be employed, the breakage of which shall be the means of
communicating the signal or alarum to miners working in a coal pit of
the presence of firedamp therein, as herein-after more fully explained.
Before entering upon the description of the Drawings accompanying
our Specification we may remark that the apparatus therein described
is substantially the same as that described in the Provisional Specification,
but as improvements in matters of detail we find it better that the lead
stand and oil vessel should be combined, because in this manner the
lamp can be trimmed and prepared in less time than if these parts were
separate. We also find it advantageous to have two (or if necessary more)
alarum bells instead of a single one, because if one should fail the other
or others will be serviceable, and the sound emitted from the apparatus
is louder and stronger than would be produced by a single bell.
find also that the apparatus described in our Provisional Specification
for carrying the gridiron valves or shutters may with advantage be
simplified in the manner herein-after described. We will now proceed
to fully describe the Drawings.
We
Fig. 1 is a vertical section through the apparatus; Fig. 2 is a detail
of the oil lamp fitted with the releasing rod; and Fig. 3 is an external
end elevation of the whole apparatus. The Figures are drawn full size.
a is the bed plate supported upon two side frames b, b; a boss c is
screwed internally to receive the oil lamp d; e is the wick, and fis the
aperture for refilling the lamp with oil; g is a shield cast into or
fixed upon the top of the lamp d, and serving the double purpose of
supporting the link of lead wire and of protecting the said link from
the heat of the lamp flame; the lead link hangs upon the pin i and
supports the rod jupon the lower hooked end j', on which rests the
bridle or cross bark of the side bars 1, 1. The upper ends of these side

page_text: bars 1, 1, are attached by screws m, m, to the gridiron valves or shutters
n, n,; o, o, are the sides of a square box, of which p, p, p, are the two ends
and top formed of one piece of metal; q, q, are two of the four openings
formed in the two sides o, o, which remain open as long as the lead wire
link supports by means of the intervening pieces j, k, land m, the
gridiron valves or shutters n, n, but which openings q are closed by
the shutters n, n, upon the breakage of the lead link h; r is a cylinder
of wire gauze, having a closed top 8, and being secured to the bed plate
a by means of a flat ring and screws u. The wire gauze cylinder
encloses the whole of the apparatus, which is attached to the top of the
lamp d and is itself enclosed within the square box o, p.
Attached to
one side p of the square box o, p, are two alarums v, v, one only
however may be used if preferred. In Fig. 3, w is the hammer for
striking the bell of the alarum. A wire x moves with the hammer w
and projects beyond the edge of the square box o, p. As long as the
shutters n, n, are supported in the position shewn a pin y upon one of
them presses against the wire of the alarum and prevents it from
ringing. When the shutters fall the wire x is released and the alarum
rings. is the pin, which acts in like manner upon the lower alarum.
The lamp d having been lighted, the lead link applied, and the whole
screwed into the bed plate a, the shutters n, n, are raised by hand until
the cross bar k can be engaged into the hook j'. The alarums are then
wound up and the complete apparatus is suspended near the roof of the
mine within a strong wooden box having two sides formed of coarse
wire netting. When the firedamp has collected in sufficient quantities
to ignite within the gauze cylinder r, the lead link / becomes destroyed
thereby, and the shutters n, n, being no longer supported fall, and
by closing the four openings q exclude the supply of air and extinguish
the lamp. At the same instant the alarum or alarums are released and
warning is given that firedamp is present.
Having now described the nature of our said Invention, and the
manner in which the same is or may be performed, we desire it to be
understood that without limiting ourselves to the details herein-before
explained, as these may be varied or modified to almost any extent
without departing from the nature of our said Invention, what we
claim as the Invention to be protected by the herein-before in part
recited. Letters Patent is, the use or employment of lead or other fusible
material for a link in the construction of a lamp, substantially as herein-
before described, such link being used as a communication between the

page_text: pin i on the upper end of the shield g and the releasing rod j which is
in connection with the bridle or cross bar k which carries the gridiron
valves or shutters n, n, so that when firedamp enters the gauze in a
sufficient quantity for combustion to take place, the heat generated by
such combustion shall have the effect of making rotten or melting the
said lead or other fusible material employed for such link, and thus cause
the alarum or alarums in connection with the apparatus to give warning
that firedamp is present, and simultaneously by the falling of the
valves extinguish the lamp, and thus effectually prevent the ignition of
firedamp outside the gauze.
In witness whereof, we, the said John Hyde and Joseph Flyde,
have hereunto set our hands and seals, this Twenty-fifth day
of January 1870.
Witness,
G. R. HOLLAND,
Patent Office,
Birmingham.
JOHN HYDE.
(L.S.)
JOSEPH HYDE. (L.S.)