Improvements in Miners' Shielded Safety Lamps.
Year: 1889

page_text: Date of Application, 16th May, 1889
Complete Specification Left, 17th Feb., 189C-Accepted, 5th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Miners' Shielded Safety Lamps.
THOMAS THOMAS 12 Danygraig Terrace Ynyshir Pontypridd Coal Miner do hereby
declare the nature of this invention to be as follows:-
Improvements in miners' shielded safety lamps.
This invention which relates to improvements in shielded safety lamps is designed;
firstly, to reduce the risks of explosions by surrounding the gauze with shields; and
also by means of a conic tube carrying a partition, so formed as to reduce the force of
the currents of air in passing through the lamps, such currents as ventilate mines and
which are liable to contain inflamable gases. Secondly: automatic lock for outer
shield, so as to safeguard against accidents and negligence in securing the aforesaid
shield.
In the first part of my invention an outer shield extends from the base ring above
the glass, to the top of the lamp, the top of the aforesaid shield is formed of a cap
rivetted to the shield: at the centre of which is formed the outlet, circular in form,
about one and one-eighth inches in diameter, over and above this outlet is a metal
covering, extending over the shield on both sides, and fixed to it by means of 3 small
supports rivetted to the top of the said shield.
The construction of the aforesaid base ring is such as to form a small chamber
immediately within the outer shield; the inner and outer parts of the base ring form
the sides of the said chamber, the ring above the glass forms the bottom, and the top
is formed by a wide rim, which is a part of the inner portion of the base ring, and
with which the said rim forms an acute angle extending to within a short distance
of the outer shield.
Holes being formed in and about the base ring to admit the necessary air to feed
the lamp the arrangement of the aforesaid small chamber; serves when the lamp is
exposed to a current of high velocity, to cause a whirl in the air at its entrance;
thereby deflecting the greater part, and admitting only the amount required to
maintain the lamp.
A large space is provided between the inner and outer shields; so as to reduce the
velocity of the air before it enters within the gauze.
Close upon, but not touching the gauze, lies the inner shield which extends from
the top of the gauze to a desired point. (about one inch from the bottom of the
gauze) where it terminates resting on the gauze. The top of the inner shield also,
is so constructed as to form an outlet of circular area one and one-eighth inches in
diameter.
Within the gauze and at this point of juncture between the inner shield, and
the gauze is the aforesaid partition, supported on the aforesaid tube; this tube
being held in position by a ring fastened near its base, and extending over the glass
on both sides.
The aforesaid tube, partition, and inner shield forming a distinct chamber, and
preventing contact between the outward and the inward currents of air, also
preventing the inward current from gaining access to the top of the lamp.
The areas of the outlets respectively are such as to regulate the feed of the
lamp and the metal covering above them, afford ample protection against any
inrush of air through the top.
The second part of my invention, consists of an automatic lock for outer shield.
It consists of a bar, pivotted at about a third of its length from one end, and
the other end pressing on a spring. On the under side and being a part of the
aforesaid bar, is a tongue, which is forced by the action of the spring into any
of the holes formed in the ring above the glass, which may coincide with the

page_text: tongue, the action of the lock is such as to admit screwing on; the tongue being
capable of gliding over the interstices; but instantly intercepts any attempt to
unscrew, until a special form of key is obtained, by means of which the tongue
is held in a position incapable of the aforesaid action.
Dated 16th May 1889
JAMES STEVENSON,
20, High Holborn, London, W.C., Agent for Applicant.
Improvements in Miners' Shielded Safety Lamps.
I, THOMAS THOMAS, 12, Danygraig Terrace, Ynyshire, Pontypridd, Coal Miner, 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:
My invention relates to certain improvements in miners' shielded safety lamps and
has reference more particularly to.
Firstly Reducing the risks of explosions by surrounding the gauze with shields;
and also, by means of a conical tube carrying a partition reducing the force of the
currents of air-which ventilate mines and which are liable to contain inflamable
gases in passing through the lamp; and,
Secondly-In providing an automatic lock for the outer shield so as to safeguard
against accidents and negligence in securing the aforesaid shield.
In order that my invention may be better understood reference is had to the
accompanying drawing wherein Figure 1 is an elevation and Figure 2 a vertical
section of my improved lamp; Figure 3 is a vertical section of the lower portion of
the outer shield or base ring shown detached, Figure 4 a vertical section of the
supporting ring and Figure 5 an elevation. partly in section, of the automatic lock
which I employ in accordance with my said invention hereinafter more particularly
.described.
In the first part of my invention A is an outer shield which extends from the base
ring C above the glass G to the top of the lamp; the top of the aforesaid shield is
formed of a cap a, rivetted thereto, at the central portion of which is formed the
outlet, circular in form, about one and one-eighth inches in diameter. Over and
above this outlet is a metal covering a' extending over the outer surface of the cap a
and fixed to it by means of three small supports riveted to the cap portion or top of
the said shield.
The lower portion of the outer shield A terminates in a base ring C, shown more
particularly in Figures and 3. Apertures or air inlets c', care formed at the
bottom and top of the base ring C; and, attached within this latter by a perforated
flange c and at a suitable distance therefrom is an internal tube I having a projecting
rim i at its upper end and formed with an internal screw thread corresponding to that
formed on the flange of the supporting ring D Figure 4. This supporting ring is
provided with apertures d and rests upon the upper edge of the lamp glass G. The
construction of the aforesaid base ring is such as to form a small chamber imme-
diately within the lower portion of the outer shield; the inner and outer parts of the
base ring form the sides of the said chamber, the ring D above the glass forms the
bottom, and the top is formed by the wide rim i which is a part of the inner portion I
of the base ring C and with which the said rim i forms an acute angle extending to
within a short distance of the outer shield A. The holes or apertures c¹..c and d.-
formed in and about the base ring C-admit the necessary air to feed the lamp, the
arrangement of the aforesaid chamber serves, when the lamp is exposed to a current
of high velocity, to cause a whirl in the air at its entrance thereby deflecting the
greater part, and admitting only the amount required to maintain a perfect
combustion in the lamp.
A large space is provided between the inner and outer shields so as to reduce the
velocity of the air before it enters within the gauze F. Close upon, but not touching

page_text: the gauze, lies the inner shield B which extends from the top of the gauze to a
desired point (about an inch from the bottom of the gauze) where it terminates
resting on the gauze by the flange and supported by the ring or flange b formed
with apertures b'. The top of the inner shield B is similar to the top of the outer
shield A and so constructed as to form an outlet of circular area one and one-eighth
inches in diameter.
Within the gauze and at the point of juncture between the inner shield B and the
gauze F is the aforesaid partition supported on the aforesaid conical tube E, this
tube E being held in position by a ring or flange e formed with perforations e
fastened near its base and extending over the upper circumferential edge of the
glass G.
The aforesaid conical tube E partition and inner shield B form a distinct chamber
and prevent contact between the outward and inward currents of air-the passage
of said currents being indicated by the arrows-and also prevent the inward current
from gaining access to the top of the lamp.
The areas of the outlets respectively are such as to regulate the feed of the lamp;
and the metal covering above them affords ample protection against any inrush of air
through the top.
The second part of my invention relates to an automatic lock for outer shield shown
at Figure 5. It consists of a bar J pivoted at j about a third of its length from one
end the other end pressing on a spring s. On the under side and being a part of the
aforesaid bar J is a tongue j¹ which is forced by the action of the spring s into any
of the holes d formed in the supporting ring D above the glass which may coincide
with the position of the tongue. The action of this automatic lock is such as to
admit screwing on, the tongue being capable of gliding over the interstices, but
instantly intercepts any attempt to unscrew, until a special form of key is obtained,
by means of which the tongue is held in a position incapable of the aforesaid
action.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:―
First The improvements in miners' shielded safety lamps substantially as herein
set forth and shown in Figures 1 to 5 of the accompanying drawing.
Second In miners' safety lamps the combination of the inner and outer
shields A, B, base ring C, supporting ring D, internal tubular portion formed
with rim and attached to base ring by the flange c, conical tube E and partition
or flange together with the special arrangement of air inlet and outlet apertures
and passages which I employ for controlling the admission of air and reducing the
velocity thereof substantially as herein set forth.
Third-fn miners' safety lamps the employment of an automatic lock for outer
shield consisting of a pivoted bar J, tongue piece j engaging with the apertures din
the supporting ring D by the tension of the spring s substantially as herein set forth
and shown at Figure 5 and for the purposes specified.
1
f
1000
JAMES
STEVENSON,
Gray's Inn Chambers, 20, High Holborn, London, W.C., Agent for Applicant.