Improvements in and relating to Safety Lamps.
Year: 1896

page_text: Date of Application, 15th July, 1896-Accepted, 14th July, 1897
COMPLETE SPECIFICATION.
Improvements in and relating to Safety Lamps.
I, ARTHUR THOMAS METCALF JOHNSON, of 109 Calabria Road, Highbury, County of
Middlesex, England, Retired Civil Servant, 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 safety lamps used for any purpose wherein it is necessary
to obviate the possibility of explosion caused by ignition of inflammable gases; but
more especially to those used in coal mines.
According to my invention the lamp is so constructed that it will give a brilliant
light, seemingly, unaffected by the most rapid currents of air, even when the latter
is moving with a velocity of 10,000 feet per minute.
Furthermore, it is not liable to extinction by inclination, or ordinary handling.
It is thoroughly unexplosive, and capable of burning petroleum, and such like oils,
with perfect safety.
To accomplish the above results I employ a cone, closely resembling the one
described in specification No. 3840, A.D. 1895.
In this instance, however, the cone surface plate is made somewhat smaller, the
ring, or its equivalent, situated on its upper surface, is formed round the outer edge
of the surface plate instead of occupying a central position as formerly. I have
dispensed with the perforated cone box, and devised the adjustment of the gauze
casing immediately over the exterior orifices of the air passages contained in the
perforated solid cone, a cone base plate, cone sub-plate, and air tight plug, and
socket, as substitutes therefor. All the above modifications are hereinafter fully
described.
An important feature of this invention, and which is subsequently explained, is the
method I have adopted for securely locking the lamp and rendering it impossible to
withdraw the locking bolt without previously extinguishing the wick flame.
In order that the nature of my invention may be distinctly understood I shall
forthwith proceed to describe the same by reference to the accompanying drawings
wherein :-
Figure 1. is an elevation of my improved lamp.
Figure 2. is a plan of my modified cone surface plate.
Figure 3. is a side elevation of my modified cone, shewing cone block, base plate,
sub-plate, and intermediate collar.
Figure 4. is a side elevation of a wick plug.
Figure 5. is a vertical central section of Figure 1 at x-x.
Similar letters in all the figures represent similar parts.
In the manufacture of this invention I construct an oil reservoir a Fig. 1, of
suitable dimensions, and material.
In the centre of the ton plata or cover thereof al an
aperture a² is made large
:

page_text: enough to admit the thimble or socket, a³ which may be smooth, fluted,
screw-threaded, or otherwise, being firmly secured thereto for the reception of the
wick plug b. Into and through the interior of the plug 6 the wick tube 61 is inserted
and securely fastened the wick tube bl projecting to the required distance beyond the
upper part of the wick plug 6 for the purpose hereinafter referred to..
In the bottom part, and sides, of the said plug suitable apertures, or slots, such
as 62 63 may be formed to prevent an accumulation of heated air within the reservoir;
which if not relieved, would cause gaseous vapours to collect therein, which, by the
ordinary force of rarefaction, would be expelled therefrom through the wick tube b',
or the customary escape tube, thereby producing an undue elongation of the wick
flame and causing the lamp to smoke.
Horizontally through the plug b the wick spindle 6* fitted with milled head b", and
toothed or roughened wheels be is adjusted for conveniently raising, or lowering the
wick when required.
On one of its extremities an eccentric 6' is attached for the purpose of depressing
the locking bolt c, the said bolt being released by a partial revolution of the spindle b*
which causes the eccentric b to become disengaged, when, consequently, the bolt c
automatically rises to its normal position by the action of the spring c¹ contained in
the shoe c² which is suitably connected to the upper part of the oil reservoir a¹ by
screws or other ordinary means.
Round the upper, and outer, edge of the top plate, or cover, a¹ of the reservoir a
hooks, or catches, a are formed thereon, or connected, for the purpose of engaging
corresponding hooks, or catches, a connected to the annular horizontal plate d fitted
with an angular flange d' the interior vertical surface of which is screw-threaded for the
reception of the screw threaded ring e which is adjusted in such a manner that the
circular cone subplate f with screw threaded periphery, can be afterwards easily
screwed therein (into d¹) for the required distance without allowing their adjoining
surfaces to come in contact. The centres of the cone subplate f and cone base
plate f, may be bored out, or otherwise removed, thereby, in conjunction with the
vertical collar f which separates the plates, forming with the plug b, when inserted,
an air tight socket f³, and allowing the projecting portion of the wick tube b¹ to pass
into, and through, the combustion chamber formed as described in my
specification 3840, A.D. 1895. On the upper part of the surface plate a ring or
its equivalent, is formed for the reception of an asbestos, or other, collar f" on which
the inner glass cylinder g rests.
The outer glass cylinder h or shield, being supported on a suitable collar situated
on the upper surface of the ring e.
Round the cone block 8 and immediately over the exterior orifices, or openings, of
the air passages fa suitable gauze casing f10 is adjusted for the prevention of back
draught.
On the upper part of the inner glass cylinder g the metallic chimney k and gauze
cylinder are fitted with suitable collars interspersed between their contiguous surfaces
as shewn at l¹ 1ª Fig. 5.
Into the annular plate d perpendicular rods m are securely fastened; their upper
ends being firmly fitted into another annular plate n constructed with an angular
posterior ring, or, flange n¹ and on the interior surface of the annular plate a suitable
number of projections are formed, against which the ring ³, connected to the gauze
cylinder l, is forced when the cone subplate f is screwed firmly into the vertical
flange di for the purpose of rendering all joints air tight that lie between those
extremities.
's
To avoid the possibility of the outer glass cylinder, or shield, h being injured by
its upper part coming in contact with the annular plate n when the vertical ring e is
screwed into the vertical flange d' an asbestos, or other, collar is conveniently adjusted
between their adjoining surfaces.
Through the flange n¹ suitable holes, or perforations, n² are formed for the purpose
of admitting the air necessary to support combustion, after which it passes downwards

page_text: between the glass cylinders g h through the gauze casing f10, into the air passages f
thence into the combustion chamber f, when it comes in contact with the wick
flame; whereupon it is immediately exhausted of its explosive and inflammable
constituents.
The upper portion of the lamp is protected from draught by the shield o which is
securely attached to the flange n' its upper part being sufficiently perforated o¹ o² to
allow the egress of heated air and products of combustion.
The top of the lamp is covered in the ordinary manner and fitted with a hook, or
ring, to facilitate carriage."
When the lamp is intended for use in a quiet, yet heated, atmosphere it is desirable
to provide the subplate f with a sufficient quantity of suitable apertures which can
be opened or closed for the admission, or exclusion, of air when required, thereby
increasing, or diminishing the draught through the cooling space p, situated between
the upper surface of the top plate a¹, and the lower surfaces of the annular
plate d flange d¹, and cone subplate f.
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
1. In a safety lamp, a bottom ring, a top ring or plate, rods connecting the two
rings, a vertical flange on the botton ring furnished with an internal screw-thread,
an outer glass cylinder, a ring screwing into the vertical flange and supporting
the outer glass cylinder and rings of suitable packing between the upper end of the
glass cylinder and the top plate and the lower end thereof and bottom plate the
parts being arranged in such manner that by screwing up the ring the glass cylinder
may be made air tight with the other parts, substantially as herein shown and
described and for the purpose stated.
. 2. In a safety lamp, the combination of a bottom ring, a top ring or plate, rods
connecting the two rings, a vertical flange on the bottom ring furnished with an
internal screw-thread, a sub-plate screwing into the flange, a perforated cone block, a
short tube or cylinder connecting the sub-plate and the perforated cone block, and an
inner glass cylinder at its lower end seated on a ring of packing carried by the
perforated cone block and at its upper end abutting against a flange of the lamp
chimney through the intervention of a suitable ring of packing the. parts being
arranged in such manner that by screwing up the sub-plate the inner glass cylinder
will be made air-tight with the cone block and chimney, substantially as herein
shown and described.
3. In a safety lamp of the character herein before described, the combination of
the cone, cone base plate, sub-plate, intermediate collar or short cylinder, and wick
plug, substantially as herein shown and described and for the purpose stated.
4. In a safety lamp of the character herein before described, forming the oil
reservoir with a short neck in such manner that a cooling space is left between the
sub-plate of the lamp and the top plate of the oil reservoir, substantially as herein
shown and described and for the purpose stated.
5. In a safety lamp, the combination of an oil reservoir provided with bayonet
catches, a lamp body provided with corresponding recesses or catches, a spring locking
bolt carried by the oil reservoir, a recess or the like in or on the body of the lamp to
receive the locking bolt, a wick raiser, and an eccentric or the like fixed upon the wick
raiser spindle and engaging the locking bolt or its spring in such manner that the
bolt cannot be withdrawn and the reservoir or container released without extinguishing
the flame of the lamp, substantially as herein shown and described.
6. In a safety lamp, the combination of an oil reservoir formed with a short neck,
a wick plug fitting the neck, a wick tube fitting the plug, a sub-plate to the lamp
located some distance from the top of the reservoir, a socket or short tube carried by
the sub-plate and adapted to receive the wick plug, a cone block carried by the socket
and provided with air ways opening into a combustion chamber, a glass cylinder

page_text: surmounting the cone block, and communicating with a suitably screened chimney,
substantially as herein shown and described..-
Dated this 15th day of July 1896.
VAUGHAN & SON,
Agents for the. Applicant.