Improvements relating to Electric Safety-lamps.
Year: 1887

page_text: Date of Application, 7th Nov., 1887
Complete Specification Left, 7th Aug., 1888
Complete Specification Accepted, 14th Sept., 1888
Improvements relating to Electric Safety-lamps. -
We, JAMES SINCLAIR, of 114 Cannon Street, in the City of London, Fire-engineer,
and JOHN PRICE REES, of 1 Boundary Terrace, Camberwell, in the County of
Surrey, Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
Our invention relates to electric safety-lamps, and is chiefly designed to facilitate
the work and diminish the expense attending the use of safety-lamps of the kind or
class wherein an incandescent electric lamp of any suitable description is enclosed in
a glass casing or lantern provided with contact pieces one of which can be moved to
and from the other and is held in contact therewith by pressure in the said casing or
lantern, a spring being combined with the said movable contact piece so that, should
the said casing be broken and the said pressure removed, the said spring will expand
and break contact between the said pieces thereby interrupting the electric circuit
and extinguishing the light.
In such safety-lamps it has been proposed to introduce water and carbonic acid
gas under pressure into the said casing or lantern to obviate the required pressure
therein. It is evident however that, in the use of such lamps, some difficulty will be
experienced in charging the said casing or lantern with water and compressed
carbonic acid gas, and that considerable expense will be involved in procuring the
carbonic acid gas for this purpose.
Now, according to one part of our said invention, we greatly simplify and facilitate
the operation of charging the said casing or lantern by the use therein of compressed
atmospheric air instead of water and carbonic acid gas. Moreover as atmospheric
air is obtainable free of cost, we considerably reduce the expense attending this
operation.
We further diminish the labour and expense attending the use of such lamps by
providing means whereby the electric circuit may be interrupted or established at
will without the necessity of detaching or unfastening the conducting wires from the
terminals of the battery or of the lamp.

page_text: Our said invention is conveniently and advantageously carried into practice as
hereinafter described, that is to say:-We'arrange an incandescent electric lamp in
an outer casing or lantern and provide means whereby contact may be maintained
by pressure within the said casing or lantern. We combine with the said outer
casing or lantern a short pipe or tube which is provided with a suitable stop cock or
valve, and through which the compressed air may be introduced into the said casing
or lantern. And we provide an air pump of suitable construction which can be
connected successively with any desired number of the safety-lamps for the purpose
of charging the casings or lanterns thereof. We find it convenient to make this
pump of such capacity that a sufficient quantity of air can be forced thereby into the
casing or lantern in a single stroke of the said pump. We may however employ
other suitable means for introducing compressed air into the said casing or lantern.
Or we provide for the compression of the air in the said casing or lantern by the
simple movement or adjustment of a piston, diaphragm or other device forming a part
of our apparatus.
We pass the conducting wires through the lid or cover of the receptacle or box
containing the battery; instead, however of connecting the two wires directly to the
poles of the battery, we secure the said wires to the underside of the said lid or cover,
so that they extend in opposite directions to the edges thereof. Moreover we provide
contact plates on the upper edge of the body of the said receptacle or box and
connect one of the said contact plates with each pole of thie, battery. These contact
plates are so arranged that, when the said box is closed, the wires on the lid or cover
will make contact with the said plates. Therefore the electric circuit may be inter-
rupted and the lamp extinguished, by simply raising the lid or cover of the receptacle
or box containing the battery, and the said circuit will be again established or
completed when the said lid or cover is closed.
We can if desired, permanently connect one of the conducting wires of the lamp
with one pole of the battery and use only one of the, aforesaid contact plates. We
sometimes use other devices for enabling the laiup to be extinguished without detaching
or unfastening the conducting wires.
It is obvious that, instead of using compressed air we can charge the outer casing
or lantern with other gas under pressure, one object which we have in view being to
dispense with the use of water in the said casing or lantern. We prefer, however, to
employ air for the sake of cheapness.
The use of water impregnated with acid in such safety lamps is disadvantageous for
various reasons amongst which are the following, viz. heat is imparted from the glass
bulb to the acidulated water which is liable to be rendered milky thereby, so that it
will obscure or diminish the power of the light. Moreover a large space is required
between the glass bulb and the outer casing in order to ensure the proper pressure
in the said casing.
We prefer to insert the outer casing or lantern in a socket in the body of the safety
lamp, and to seal it therein by means of wax or other suitable material. We can,
however, arrange the said casing in any other convenient manner.
Dated this 7th day of November 1887.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.

page_text: We, JAMES SINCLAIR of 114 Cannon Street in the City of London, Fire Engineer,
and JOHN PRICE REES, of 1 Boundary Terrace, Camberwell, in the County of Surrey
Electrical 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:
:-
Our invention relates to electric safety-lamps.
The said invention is chiefly designed to facilitate the work and diminish the expense
attending the use of apparatus of the kind or class wherein an incandescent electric
lamp of any suitable description is enclosed in a glass casing or lantern provided with
contact pieces one of which can be moved to and from the other and is held in contact
therewith by pressure in the said casing or lantern, a spring being combined with the
said movable contact piece so that, should the said casing be broken and the pressure
removed the said spring will expand, and break contact between the said pieces
thereby interrupting the electric circuit and extinguishing the light.
In such safety-lamps it has been proposed to introduce water and carbonic acid gas
under pressure into the said casing or lantern to obtain the required pressure therein.
It is evident however that, in the use of such lamps, some difliculty will be experienced
in charging the said casing or lantern with water and compressed carbonic acid gas,
and that considerable expense will be involved in procuring the carbonic acid gas for
this purpose. Moreover the use of carbonic acid and water is disadvantageous for the
reasons hereinafter mentioned.
Now, according to one part of our said invention, we greatly simplify and facilitate
the operation of charging the said casing or lantern by the use therein of compressed
atmospheric air instead of water and carbonic acid gas. Moreover as atmospheric
air is obtainable free of cost, we considerably reduce the expense attending this
operation.
We further diminish the labour and expense attending the use of such lamps by
providing means whereby the electric circuit may be interrupted or established at will
without the necessity of detaching or unfastening the conducting wires from the
terminals of the battery or of the lamp.
In the accompanying drawing we have shown how our said invention can be
conveniently and advantageously carried into practice.
Figure 1 is a plan partly in section of one form of my improved lamp.
Figure 2 is a vertical longitudinal central section some of the parts being shown in
elevation.
Like letters indicate corresponding parts throughout the drawing.
A is a portion of the box or case intended to contain the battery. B is the lid or

page_text: a is an incandescent electric lamp, 6 an outer casing or lantern fixed in a suitable
rocket attached by screws or in any suitable manner to the lid or cover B, of the
box or case A, containing the battery.
To maintain contact by pressure within the said casing or lantern b, we provide the
said socket 6 of the outlet casing or lantern 6 with a short pipe or tube e which is
provided with a suitable stop cock or valve d and a nozzle c' through which the
compressed air may be introduced into the said casing or lantern b. And we provide
an air-pump of suitable construction which can be connected successively with the
nozzles c¹ of any desired number of the safety-lamps for the purpose of charging
the casings or lanterns thereof. We find it convenient to make this pump of such
capacity that a sufficient quantity of air can be forced thereby into the casing or
lantern in a single stroke of the said pump. We may however employ other suitable
means for introducing compressed air into the said casing or lantern b.
Or we
provide for the compression of the air in the said casing or lantern by the simple
movement or adjustment of a piston, diaphragm or other device forming a part of our
apparatus.
We pass the conducting wires e through the lid or cover B, of the receptacle or
box A containing the battery; instead however, of connecting the two wires e directly
to the poles of the battery we secure one of the said wires to a piece e¹ which passes
through the bottom of the socket and is suitably insulated therefrom. The said
picce e forms contact with a contact plate or piece fitted upon the underside of the
lid or cover B.
The other wire e is connected to the bottom of the socket & carrying the casing b.
To complete the circuit by the air or other pressure inside the casing we prefer to
provide at the bottom of the socket carrying the said casing a flexible diaphragm f
which when expanded by the said pressure will bear upon a contact piece g, and cause
the latter to complete the circuit through the plate h, and a contact plate or piece es
fitted upon the underside of the cover B. The contact piece y is normally maintained,
in such a position by a spring gas to be out of contact with the plate h, so that
should the outer casing & be broken and the pressure upon the diaphragm f. be thus
removed the said contact piece g will be raised by the spring g' and the circuit be
thus broken.
We prefer to complete the circuit between the contact pieces e³, e³, and the battery
by means of contact plates or pieces i fitted on the upper edge of the body of the said
receptacle or box A.
The contact plates or pieces e²es are preferably formed of springs so as to ensure
proper contact and are so arranged that, when the said box is closed, they will form
contact with the contact plates or pieces i. Therefore the electric circuit will be
interrupted and the lamp extinguished, by simply raising the lid or cover B of the
receptacle or box A containing the battery, and the said circuit will be again
established or completed when the said lid or cover B is closed.
We
We can, if desired permanently connect one of the conducting wires of the lamp
with one pole of the battery, and use only one of the aforesaid contact plates.
sometimes use other devices for enabling the lamp to be extinguished without
detaching or unfastening the conducting wires.
It is obvious that, instead of using compressed air, we can charge the outer casing
or lantern with other gas under pressure, one object which we have in view being to
dispense with the use of water in the said casing or lantern. We prefer, however,
to employ air for the sake of cheapness.
The use of water impregnated with acid in electric safety lamps is disadvantageous
for various reasons amongst which are the following viz.
glass bulb to the acidulated water which is liable to be
that it will obscure or diminish the power of the light.
required between the glass bulb and the outer casing in
pressure in the said cusing.
Heat is imparted from the
rendered milky thereby, so
Moreover a large space is
order to ensure the proper
We prefer to insert the outer casing or lantern in a socket attached to the body of
the safety lamp as hereinbefore described, and to seal it therein by means of wax or

page_text: other suitable material. We can however, arrange the said casing in any other
convenient manner.
Having now particularly described and ascertained the nature of our invention and
in what manner the same is to be perforined, we wish it understood that we do not
claim the use, for the purpose above specified, of water impregnated with carbonic
acid gas but we claini
:
First. The above described method of providing for the extinction of the light in an
electric safety-lamp on the breakage of the outer globe or casing thereof, by the
introduction of compressed air or other gas into the said globe or casing, as, and for
the purpose, above specified.
Second. The means substantially as described for interrupting or breaking the
circuit and extinguishing the light when the lid or cover of the box or case containing
the battery is opened, and for completing or re-establishing the said circuit when the
said lid or cover is closed, as set forth.
Third. The improved electric safety lamp consisting of the parts constructed and
combined substantially as described with reference to the accompanying drawing for
the purpose specified.
J. P. REES.
Haseltine, Lake & Co.,
45, Southampton Buildings,
Agents for the Applicants.