Improvements in Electric Safety Lamps for Use in Mines and other Places.
Year: 1886

page_text: Date of Application, 18th Nov., 1886
Complete Left, 17th Aug., 1887.
Complete Accepted, 20th Sept., 1887.
Improvements in Electric Safety Lamps for Use in Mines
and other Places.
I MILES SETTLE of Darcy Lever near Bolton in the County of Lancaster Colliery
Proprietor and Mining Engineer do hereby declare the nature of this invention to be
as follows:-
This invention relates to improvements in the construction of electric safety lamps
for use in coal and other mines, or in other places where there is danger of an
explosion, and consists of improvements upon an electric safety lamp for which I
applied for Letters Patent on the 8th day of September 1886 No. 11,413, wherein the
electric contact was maintained by means of a float to which the lamp was attached
and by which it was supported.
According to my present invention instead of using a float to support the lamp
and thus to maintain electric contact I attach the lamp to a resilient diaphragm
which forms the bottom of the outer glass casing and I fix the movable contact pieces
to the other side of the said diaphragm.
The diaphragm is fixed all round between flanges (or otherwise) so as to be air and
water tight; it may be either flat or dome-shaped.
In the former case it will act by its elasticity, and in the latter case by its
resiliency in such a manner as to keep the contact pieces asunder until pressure is
applied inside the glass casing when the diaphragm will give way and allow the
movable contact-pieces to come against the fixed contact-pieces, and thus establish
the electric contact necessary for producing the light, but as soon as the pressure is
withdrawn from the interior of the glass casing the elasticity or resiliency of the
diaphragm comes into action and draws the contact pieces asunder and thus
extinguishes the light.

page_text: The pressure in the outer glass casing may be produced by water only, admitted
through a flexible tube in which case it acts merely by its own weight or dynamic
pressure.
Or, it may be water or other liquid under the pressure of compressed air, carbonic
acid gas, or other elastic fluid; or compressed air, carbonic acid gas, or other elastic
fluid, without the water or other liquid, may be used.
In either case the escape of the water or compressed fluid (whether liquid or
aeriform or both combined) from the glass casing will withdraw the pressure and the
elasticity or resiliency of the diaphragm will draw the contact pieces asunder and
thus extinguish the lamp.
Dated this 17th day of November 1886
GEORGE DAVIES,
4, St. Ann's Square, Manchester,
Agent for the Applicant.

page_text: Improvemenis in Electric Safety Lamps for Use in Mines
and other Places.
I MILES SETTLE of Darcy Lever near Bolton in the County of Lancaster Colliery
Proprietor and Mining Engineer do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
-
This invention relates to improvements in the construction of electric safety lamps
for use in coal and other mines, and in other places where there is danger of an
explosion, and consists of improvements upon an electric safety lamp for which
Letters Patent have been granted to me bearing date the 8th day of September 1886,
No. 11413, wherein the electric contact was maintained by means of a float to which
the lamp was attached and by which it was supported.
The nature of my present invention and the manner in which the same is to be
performed or carried into practical effect will be readily understood on reference to
the accompanying drawing and the following explanation thereof.
The drawing represents a vertical section taken through about the centre of my
improved lamp.
According to my present invention instead of using a float to support the lamp a, a
and thus to maintain electric contact I attach the lamp to the lower side of a resilient
diaphragm b, b which is secured by its outer edge to, and forms the top of, the metal
ring or casing c, c of the outer glass d, d and I fix movable contact pieces or pins e, e
to the upper side of the said diaphragm.
The latter is fixed all round between the flange f, f and the lid 9, 9 (or otherwise)
an india rubber or other suitable packing ring h, h being interposed so as to make
the joint air-and-water-tight; the diaphragm b, b may be either flat or dome shaped.
In the former case it will act by its elasticity and in the latter case by its resiliency
in such a manner as to keep the movable contact pieces e, e and the fixed contact
pieces i, i asunder until pressure is applied inside the glass casing d, d when the
diaphragm b, b will give way and allow the movable contact pieces e, e to come
against the fixed contact pieces i, i (as shown on the drawing) and thus establish the
electric contact necessary for producing the light, but as soon as the pressure is
withdrawn from the interior of the glass casing d, d the elasticity or resiliency of the
diaphragm comes into action and draws the contact pieces asunder and thus
extinguishes the light.
I would here remark that, if preferred the diaphragm need not be elastic or resilient
in itself, but it may be made of suitable flexible material such as leather for
example and be held down (so as to keep the contact pieces asunder) by means of a
spring or springs.
The pressure in the outer glass d, d requisite for overcoming the resistance of the
diaphragm and for bringing the contact pieces together may be produced by water

page_text: only which is admitted by a tap or valve and a flexible tube attached to the
short pipe k, k in which case it acts merely by its own weight or dynamic
pressure.
Or it may be water or other liquid under the pressure of compressed air, carbonic
acid gas or other elastic fluid; or compressed air, carbonic acid gas or other elastic
fluid, without the water or other liquid may be used.
In either case the escape of the water or compressed fluid (whether liquid or
aeriform or both combined) from the glass casing d, d will withdraw the pressure, and
the elasticity or resiliency of the diaphragm b, b will draw the contact pieces asunder
and thus extinguish the lamp.
1, 1, is a spring which enters a notch m in the rod n, n attached to the diaphragm
and holds the contact pieces asunder until released by hand, so as to prevent their
being accidentally brought together again and igniting the lamp after it has been
extinguished.
Any other suitable form of spring bolt or latch may be employed for this
purpose.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is :—
In an electric safety lamp, a flexible or resilient diaphragm having the lamp
attached to one side and a movable contact piece or pieces to the other, such
diaphragm forming the top or other movable portion of an air and liquid tight casing
or vessel, and being acted upon by the pressure of a liquid or other fluid inside the
vessel in combination with a fixed contact piece or pieces outside the said casing or
vessel; the pressure of the liquid or other fluid serving to keep the contact pieces
together so as to complete the electric circuit and thus maintain the light in action
and the escape or absence of the liquid or other fluid from the casing or vessel
withdrawing the pressure and allowing the elasticity or resiliency of the said
diaphragm to draw the said contact pieces asunder and thus extinguish the light
substantially as hereinbefore described and illustrated by the drawing annexed.
Dated this 16th day of August 1887.
GEORGE DAVIES,
4, St. Ann's Square, Manchester,
Agent for the Applicant.