IMPROVEMENTS IN MINERS SAFETY LAMPS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Thomas Thomas at the Office of the
Commissioners of Patents on the 1st November 1883.
THOMAS THOMAS of Treorky in the Parish of Ystradyfodwg county of Glamorgan
Colliery Manager "IMPROVEMENTS IN MINERS SAFETY LAMPS"
This Invention relates to improvements in Miners' safety lamps.
A lamp constructed according to this Invention is of the following general
description.
The upper part of the lamp consists of the frame for double glasses or glass tubes,
gauze tube, metal tube and chimney or lamp top, and the lower part of the lamp
consists of the lamp proper with air passages, oil box, wick tube and wick and
appliance for extinguishing the light in the event of an attempt to open the lamp,
and the lock to effectually secure the lower to the upper part to prevent the lamp
being opened by unauthorised persons. In the upper part of the lamp, the double
glasses, one inside the other, are comparatively short and stand on, and are retained
by, separate Screw rings, and enter into recesses in the middle ring to which the
bottom end of the gauze tube is secured. The frame has at its base a screwed flange
to receive and retain the screw rings for the glasses and the lamp proper or oil box.
The bars supporting the middle flange on the lower flange of the Frame are solid,
but those supporting the dome or lamp top and chimney are hollow and_commu-
nicate with the interior of the lamp top to admit air thereto. The dome or lamp top
forms an upper, or hot air, chamber and is ventilated by the air admitted through
the hollow standards. The lamp top, or hot air chamber, has a perforated top and
a damper, or sliding cover, by which it can be closed. The gauze tube is closed at
the top and is by preference made double at and near the top end. Inside the
gauze tube is a plain open ended metal tube as a protection to the flame in a strong
current of air. The lamp box, or lamp proper is circular and has at its under sido
an air chamber by preference perforated radially in the circumference thereof with
small holes for the admission of the air and communicating with the top side by
perforations, or tubes, the tubes or perforations being covered at each end with
gauze. The wick trimmer is passed through the oil box in the ordinary manner
and is of ordinary construction. The wick holder consists of an inner and outer
tube with spring, the inner tube being dished or cupped at its lower end and
flanged outwards to hold the spring, the outer tube is flanged outwardly at its
base, the spring is spiral and works freely between the inner and outer tube; the
wick passes up the centre of the inner tube, and the inner and outer tube are slotted
to admit the end of the trimmer to raise the wick; the inner tube rosts on a flange
in the mouth of the oil box, and when the spring is compressed by the flange of the
outer tube, the upper end of the inner tube is level with the top of the outer tube.
The mouth of the oil box is flanged and is screwed internally to receive a flanged
cap; a band or hoop surrounds the flange of the cap, and this band is fitted with a
bent rod which projects over the top of, and inside, the cap or cover, the band or

page_text: •
hoop is free to revolve round the flanged cap or cover; as the flanged cap or cover
is screwed into the mouth of the oil box it, forces down the outer tube and
compresses the spring. The band or hoop is fitted with a horizontal pin or stud
projecting outwards, and the screwed ring which secures the inner glass is notched
in its under face to receive the said pin or stud; the flange of the outer wick-tube
is perforated to allow it to receive and slide on the trimmer tube which acts as a
guide for the outer wick-tube and prevents it turning round in the mouth of the oil
box when acted on by the spring; the said flange of the outer wick-tube is also
perforated to receive the end of the bent rod which is fitted to the band, or hoop,
and projects over the cap or cover aforesaid, so that when the hole in the flange is
brought round under the said bent rod the said outer-wick-tube is free to move
upwards and can be, and is, forced upwards by the action of the spring under it,
but when the lamp is in use the end of the bent rod is in contact with the solid
part of the flange of the outer wick-tube and prevents it rising; the top of the oil
box is fitted with two studs or stops to prevent the band or hoop (and bent rod)
turning too far. In the operation of putting the lamp in order, the wick is inserted
in the inner wick-tube, the spiral spring is placed round the inner tubo resting in
the cup or dish thereon, the flange of the said inner tube is placed on the flange of
the mouth of the oil box, and the outer wick-tube is placed over it, being threaded
over the wick trimmer; the cap or cover, (with the band or hoop thereon,) is
screwed into the projecting flange of the mouth of the oil box, the bent rod which
projects over and into the cap, or cover, forcing down the outer wick-tube and
compressing the spring as the cap or cover is screwed down. The inner and outer
glass tube being placed in position, the inner and outer retaining rings are screwed
into the bottom flange of the lamp frame until they are in contact with the said
glass tubes. The wick is then lighted and the lamp box is screwed into the said
bottom flange of the lamp frame, the projecting stud on the band or hoop aforesaid
entering into one of the recesses in the under face of the inner retaining ring; when
the lamp box is unscrewed-turned from right to left the bent rod in contact
with the plain or solid part of the flange of the outer wick-tube is held stationary
and the oil box and outer wick-tube being rotated the hole in the flange of the
outer wick-tube is brought round under the said bent rod and the spring then
forces up the outer wick tube and the light is thereby extinguisher.
The locking apparatus consists of a screw pin with a square centre and a long
round head, and key corresponding in shape to the square centre and round head
of the screw pin, the lamp box has a projecting boss on the side thereof which is
screwed internally to receive the screw pin; the under face of the bottom flange of
the lamp frame is grooved concentrically in part only to receive the point of the
screw pin. In fixing the lamp box in position, the screw pin is drawn within the
boss and when the said lamp box is in position the screw pin is advanced by
turning it with the key, until the point of the screw pin is forced into one of tho
grooves in the under face of the bottom ring or flange of the frame; this in itself
will lock the lamp, but if great force is used in unscrewing the lamp box, it might
be turned until the pin is at the end of one of the grooves where it would be held,
but the act of unscrewing the lamp box would extinguish the light before it had
made one complete revolution, and before the lamp had been rendered dangerous,
as before described in reference to the action of the spring in forcing tip the outer
wick-tube
By preference the key of the locking apparatus is made so thin, and the key-hole
in the boss so small that the screw-pin cannot be turned, and the lamp unlocked,
without the proper key