Year: 1887

page_text: Date of Application, 26th Mar., 1887
Complete Left, 23rd Dec, 1887
Complete Accepted, 27th Jan., 18880
I, THOMAS MARSHALL of Durham Villa, Arlington Road, Surbiton, in the county
of Surrey, Gentleman do hereby declare the nature of this invention to ho as
follows :-
My invention relates to an improved miners' safety-lamp, to an improved perforated
metal gauze for use in such lamps in place of the ordinary gauze, and to a shield, form-
ing a reflector and shut-off appliance for the Davy, Pieler, Clanny or any other suitable
miners' lamp.
My new lamp has, in the usual manner, a glass cylinder carried in a frame composed
of two rings connected by pillars or standards, the bottom ring having an internal
screw thread into which is screwed the oil vessel, and also the ring-plate for fixing
the said glass cylinder. The said ring-plate has a collar rising vertically around the
sides of the glass cylinder about one quarter of an inch, which collar fits tightly
around the glass cylinder or leaves space enough for a lining of leather, asbestos,
india-rubber, putty or any suitable packing, which also is carried under the bottom
edge of the glass cylinder and above the ring-plate. Collars can also be formed to
pack the inside of glass cylinder with packing rings, or the metal collars to fit close
to the glass, in the same manner as described for the outsides of the glass. In the
top edge of the lower ring of the lamp frame is placed a small screw lock, the point of
the screw locking tightly against the side of the collar attached to the said ring-plate.
This is to prevent the glass by any means working loose. The glass can be cleaned
without removing it from the lamp.
Above the glass cylinder is a collar ring the lower end of which fits over the top of
the glass cylinder and is lined with packing rings in the same manner as the above-
mentioned ring-plate. The said collar-ring has near its upper end an internal flange
and an internal screw thread above the said flange. The lamp is provided with a
chimney having an external flange near its upper end and the said flange lodges on
the flange of the collar-ring, the chimney depending therefrom. The said chimney

page_text: extends about one quarter of an inch above the flange formed thereon and fits closely
inside the bottom of a short cylindrical gauze cap whose bottom edge rests on the
flange on the chimney. A screw ring is passed over the cylindrical gauze cap and is
screwed into the top of the said collar-ring tightly down on to the flanges of the
cylindrical gauze cap and chimney. The chimney descends considerably below the
top of the glass cylinder to conduct the burnt air from the wick-flame (which
is placed centrally below it) into the cylindrical gauze cap, through which the
burnt air passes out of the top of the shield hereinafter mentioned, and thence out of
the lamp.
The aforesaid collar-ring is perforated closely with holes and is covered on the
outside with gauze. The outside of the collar-ring is grooved above and below the
holes, and has a small portion cut out to enable the full width of gauze to be passed
in round the said collar-ring, the seam in the gauze being folded at the cut out
portion. This plan is to prevent the possibility of any inlet existing except through
the holes in the collar-ring and the gauze which covers the holes, and to keep the
gauze from working loose.
The said collar-ring may be cast with vertical divisions inside, the said divisions
extending the full length of the said collar-ring from the glass cylinder to the flange
at the upper part of the said ring, the divisions touching the sides of the chimney and
thus dividing the inlet current of air, so that if the lamp is tilted in burning fire-
damp, the burnt air will pass out again in each division through the said collar-ring.
The shield herein before mentioned, is formed in two halves. The upper half, which
covers the cylindrical gauze cap, is formed with a conical top and an outlet aperture of
about one half or three quarters of an inch and at its bottom edge it fits closely round
the top of the inlet collar-ring, thus separating the inlet from the cylindrical gauze
cap outlet. The lower half of the shield has a row of holes in its upper portion
above which the said lower half is carried inwards to the sides of the upper half of
the shield, to which it is securely rivetted or otherwise fixed. The bottom half of the
shield rises above the lower end of the upper half of the shield leaving a space between
the sides of the two halves of the shield for air to pass through the holes in the lower
half of the shield into the lamp. The bottom of the lower half of the shield is fixed
to a screw-ring which screws the shield on to the upper ring of the lamp frame. A
flange or small flanges, with holes for the shoulders of the upper pillars supporting the
top cap of lamp, is made to screw into the said screw-ring and fix the shield
thereto.
The top cap of the lamp can be fixed to the upper half of shield and be of any
convenient shape, and the upper pillars be dispensed with.
A shut-off appliance to be operated by the miner is formed by a plain band of metal
fitting around the lower half of the shield and extending from the bottom thereof up
to the inlet holes in the said lower half of the shield. The supply of air is shut off
by simply raising the said band by hand so as to cover the inlet holes.
I form a pillar lock for my improved lamp and other miners' safety-lamps by one
of the lower pillars. The said pillar is not fixed but can slide up and down through
holes in the flanges of the upper and lower rings of the lamp frame. When applied
to my improved lamp it operates in the following manner. The above-mentioned
shield is screwed on and the loose pillar is slid up as high as it will go through a hole
drilled in the flange of the screw-ring affixed to the bottom of the shield. The oil
vessel is then screwed in and the loose pillar pulled down until its lower end fully
enters a hole formed in the thick part of the oil vessel but the said pillar is of such
length that a small portion of its upper part still remains in the shield-ring, and locks
it fast while the lower end of the said pillar locks the oil vessel. A hasp can be fixed
on the pillar lock and pass over a projecting eye on the bottom ring of the lamp
frame. The eye is then plugged with a lead rivet. Or a block or thick ring is fixed
on the pillar, to project so as to touch the lead rivet and prevent the pillar lock being
raised. Or the lamp can be locked with a screw-lock.
The pillar lock can be made to operate in. connection with the shut-off appliance in

page_text: the following manner. The band of metal forming the said appliance has a vertical
groove formed in its side and a small flange at bottom on the same side. A spring is
fixed inside the shield, the point of the said spring passing through a slot hole in the
shield and entering the groove in the shut-off appliance when the said flange on the
bottom of the shut-off appliance covers the pillar lock. Therefore the shut-off appliance
must be raised and thus cut off the supply of air and put out the light or firedamp,
before the pillar lock can be released from the oil vessel and the oil vessel unscrewed,
and this must also be done before the pillar lock can be pulled down to release and
unscrew the shield, after which the spring is withdrawn from the groove in the shut-off
appliance which is revolved a little, ready for screwing on the shield. After the
shield and oil vessel are screwed on and the pillar lock is locked the shut-off appliance
is revolved until the flange covers the pillar lock and the point of the spring catches
into the groove. Then the shut-off appliance must be raised to open the lamp. More
screw thread must be worked on the oil vessel and bottom ring of lamp frame if this
plan is adopted, and then it will not require a lead rivet or a screw-lock.
The air passes into the lamp first through the outer holes in the shield, then down
between the upper half of bottom part of shield and bottom of upper half of shield,
through the gauze-covered perforated collar-ring outside the chimney to the flame,
the burnt air rising upwards inside the chimney through the cylindrical gauze cap
into the upper chamber of the shield and out through the aperture in the top of the
shield.
The picker is arranged to snuff the whole of the wick, one half at a time, besides
raising or lowering the wick, thus forming a combined snuffer and picker. The picker
is bent horizontally to reach across the whole of the wick-tube, then rises upwards and
inwards and forms the tongue for raising or lowering the wick, the horizontal part
forming the snuffer.
If the picker cannot be made to snuff the wick, a separate tube may be fixed in the
oil vessel beside the picker tube and a separate wire snuffer may be added in this
tube, the top of the snuffing wire being bent at right angles to reach horizontally
across the whole of the wick tubo.
The above-mentioned cylindrical gauze cap may, if desired, be made conical
as may also the whole of the upper half of the shield hereinbefore described.
My improved lamp can be made of any convenient size.
My improved gauze for use in miners' safety-lamps is to be made of sheet metal
perforated like a nutmeg-grater, except that the edges of the holes must be smooth and
not rough. It can be made in the following manner. A flat die having a number
of small holes close together is made of hard metal, and another die is provided
having a number of small pins made to enter the holes in the other die. A sheet of
copper, or other metal is laid between the dies which are then pressed together. The
pins pierce a number of holes closely together and turn the forced-out metal edges of the
holes into the other die thus forming a number of short tubes all over the sheet of
metal as closely together as possible and as nearly as possible as fine as the apertures
in a Davy gauze. This gauze may be used in any safety-lamp instead of the ordinary
wire Davy gauze. My improved lamp can be used with this new gauze or with
ordinary Davy gauze as preferred.
My improved shield for the Davy, Pieler, Clanny or other suitable miners' safety-
lamp is made in two halves vertically, one half forming a plain or corrugated
reflector, and the other half made to slide round from behind the reflector half, and
close into a circle. This shield when placed around a Davy, Pieler, or similar lamp,
and closed together into a circle shuts off all air froin the lamp and safely extinguishes
the light or fire damp in any velocity. The shield may also be made so that the
reflector half will slide and the outer half be fixed. The said shield can be made on
new Davy, Pieler, or any other suitable lamps with the metal-work forming the ring-
slides, but for old lamps in use, special grooved rings or round rings are used passing
through holes in the two halves of the shield thus making the shield complete to be
placed round any lamp.

page_text: A screw with a flat head or thumb-screw head may be screwed into the top or
bottom ring of the said shield to securely fix the shield to the lamp and the ring of
the shield may be bevelled or inclined on the inside to wedge on the ring of the lamp
frame or a vertical groove may be cut in the ring of the shield to catch into any
projecting part of the lamp to fix the shield, instead of the said screw. The sides of
the halves of the shield may be turned out or in at right angles so that a space exists
between the two halves of the shield when open, and when closed the turned out or
turned in edges come together.

page_text: DRAWINUT.
Figure 1 is a vertical section of my improved miners' safety lamp. Figure 2 is a
vertical section of a portion of the said lamp. Figure 3 is a horizontal section on the
line figure 1. Figure 4 is a plan of the picker.
My improved lamp (Figure 1) has, in the usual manner, a glass cylinder A enclosed
in a frame composed of two rings B and C connected by pillars or standards D, the
lower ring B being furnished with an internal screw thread into which is screwed the
oil vessel E and also the ring plate F for fixing the glass cylinder A. By my invention
I form on the ring plate F a collar ring or flange F' which rises vertically round the
outside of the bottom of the glass cylinder A, the outer circumference of the said ring F¹
being bevelled inwards from the top downward. Combined with this collar ring or
flange F¹ I use a small screw-lock S in the upper portion of the ring B of the lamp
frame the point of the screw lock S locking tightly on to the side of the collar
ring F attached to the ring plate F. This fixes the glass cylinder A and positively
prevents the said glass cylinder working loose when screwing on the shield L, and
the screw lock S or its equivalent is absolutely necessary. As the lamp can be cleaned
when the oil vessel E and shield L are unscrewed from the lamp, without removing the
glass cylinder A the said glass cylinder can be cemented in, or asbestos rings used as
in other miners' lamps.
My invention also consists in improvements in the air supply as hereinafter
described, the said improvements consisting in the combination with a cylindrical
gauze cap, of a gauze covered perforated ring, a chimney depending from the said
ring into the lamp, within the glass cylinder, and a novel form of shield which encloses
the gauze cap within a separate chamber so that the said gauze cap is used as outlet
only. A collar-ring H having its bottom part formed with a shoulder H and a ring
or flange H¹ (see figure 2) is fitted over the top of the glass cylinder A. The inner
diameter of the collar-ring H is the same as the inner diameter of the glass cylinder A
The collar-ring H has near its upper end an internal flange H2 and an internal screw
thread H above the said flange, and the said collar-ring is perforated with a number
of, holes which on the outside are covered with a strip of gauze H. The upper and

page_text: lower edges of the said gauze are run into the grooves H* formed round the collar-
ring H as shown in figure 2, to secure a good joint, and the gauze ends should be
overlapped and tightly stitched down to the collar-ring H or otherwise securely fixed,
as the safety of the lamp entirely depends upon the gauze being securely fastened.
A chimney I depends centrally over the wick-tube by the external flange I' near
its upper end, the flange I' resting on the flange H of the collar-ring H. A gauze
cylindrical cap J with an external flange at bottom rests on the flange I of
the chimney I, and the chimney 1 and gauze cylinder J are securely fixed to the
collar-ring H by the screw ring K which is screwed into the screw thread H³ inside
the top of the collar-ring H. The portion of the chimney I above its flange I' fits
closely around the inside of the gauze cylinder J at the bottom thereof, thus securing
a good joint. The chimney descends considerably below the top of the glass cylinder
to conduct the burnt air from the wick-flame (which is placed centrally below it) into
the cylindrical gauze cap, through which the burnt air passes out of the top of the
shield hereinafter mentioned, and thence out of the lamp.
The shield L is of novel construction. It consists of two metal cylinders fitting
within each other as shown in figure 1, with an annular space between them, the
outer cylinder or lower half being secured to the inner cylinder or upper half of the
shield near its upper end, the lower end of the outer half extending below the inner
half of the shield. The upper half L' has a conical top L' attached to its upper end
and the bottom edge L of the upper half L is turned outwards. The conical top L²
has an outlet aperture of about one half or three quarters of an inch in diameter. The
lower end of the upper half I is made to fit closely round the outside of the top of
the collar-ring H¹ but is not fixed thereto, for the purpose of enclosing the whole of
the gauze cylindrical cap J within a separate chamber. The bottom half L³ of the
shield L rises considerably above the bottom of its upper half and is formed at
top with a shoulder and flange and is securely rivetted or otherwise fixed to the sides
of the upper half L' as shown at L. The inlet holes L in the bottom half L³ are placed
near its upper end and may be six holes each about three-sixteenths of au inch
diameter or a sufficient number of holes each of one-sixteenth of an inch diameter.
Through these holes L' the air enters the annular space between the halves L' and L³
of the shield. A narrow space is left between the turned out end L at bottom of the
upper half L of the shield L and the lower half L3 of the said shield for air to pass
downwards between the two halves Land L3 and thence through the collar-ring H
to the flame, as shown in figure 1. A cylinder of metal can be rivetted to the screw
ring K and surround the gauze cylindrical cap J rising as high as the top of the said
gauze cylindrical cap, but this cylinder of metal is not necessary, as the joint between
the top of the collar-ring H and the bottom end I of the upper half L' of the
shield L is quite sufficient to enclose the outlet gauze cylindrical cap J into a separate
chamber within the upper half L of the shield L, the chimney I cutting off all
connection with the inlet air passing through the inlet ring H. A screw ring M is
fixed to the bottom of the lower half L of the shield L by which screw ring the
shield is screwed on to the upper ring C of the lamp frame, the ring C being
provided with a screw flange or collar for the purpose. A band of metal surrounds
the lower portion of the lower half L3 of the shield L, the said band of metal Q
forming a shut-off appliance which can be raised so as to cover the inlet holes L' in
the shield L, thereby excluding the air and safely extinguishing the firedamp when
ignited within the lamp, in one or two seconds in any velocity of air current.
The pillars O are fixed at their lower ends to the screw ring M, the upper ends of
the pillars supporting the top P above the conical top L of the shield L. The
top P may be a small flat one, or a larger oval or dished one with a band of holes
punched in it to allow the burnt air to pass freely from the lamp. The outlet draught
must not be checked or a bad light will be the result. The handle loop is fixed to
the eye placed in the centre of the top P.
My invention further consists in a pillar lock for locking the shield and oil vessel to
the lamp. The said pillar lock T is formed with a movable vertical pillar or standard T,
passing through holes in the two rings B and C of the lamp frame and is sufficiently

page_text: long to enter a hole in the thickness Z of the shoulder of the oil vessel E, also at its
upper end entering a hole in the flange of the screw ring M attached to the shield L.
A hasp is fixed to the pillar T just above the screw ring B of the lamp frame, and
the said hasp passes over an eye U fixed to and projecting from the side of the screw
ring B.
When the hasp R is passed over the eye U, it holds the pillar. T¹ suspended
with its upper end entering the hole in the flange of the screw ring M. and its lower
end entering the hole in the thickness Z in the oil vessel E, effectually locking the
shield Land oil vessel E to the lamp, but when the hasp R is slipped off the eye U
the pillar T can be raised or lowered and thus allow the oil vessel E and shield L to
be unscrewed. A lead rivet or padlock is passed into the eye U to lock the hasp R.
The pillar lock T can also be arranged to lock with a screw lock but the lead rivet is
safer. A small stop W is fixed on the upper part of the pillar T below the ring C to
prevent the said pillar being raised too high. The pillar lock T can also be arranged
thus The hasp R can be fixed to the pillar T below the flange of the ring B
of the lamp frame, and the eye U for lead rivet be fixed to and project from
the side of the oil vessel E. The hole and thickness Z in the oil vessel E are then
dispensed with, the bottom of the pillar T being cut off just below where the
hasp R is fixed thereto. The stop W is fixed just a little above the flange of the ring B
of the lamp frame. When a screw is used to lock the lasp R, the said hasp is cast with
a boss on its lower end through which the screw passes into a boss on the ring B of
the lamp frame.
My invention further consists in an improved form of picker which is made to
completely snuff the wick as well as raise it. The mouth of the oil vessel E is made
as large as possible. The picker V is formed at its upper end with a horizontal
portion sufficient to extend across the top of the wick tube. It is then curved
upwards at V2 and towards the centre of the horizontal portion V₁ and formed with a
tongue V3 at about right angles to the portion V₁ to enter the slot hole in the wick
tube and raise the wick. The wick is sniffed by drawing down the picker so that the
horizontal portion Vlies across the centre of the wick-tube and then turning it
horizontally, cutting off half the snuff at a time, the whole of the wick being
relighted before the other half of the snuff is struck off; thus the wick can be com-
pletely snuffed without extinguishing the light. The horizontal bar VI should be
curved horizontally as shown in figure 4 to sink into the mouth of the oil vessel E.
The air passes through my improved lamp as indicated by the arrows. The air
passes through the inlet holes L'in the lower half of the shield L, thence down-
wards between the two halves L' and L³ of the said shield, thence through the gauze-
covered holes in the collar-ring H outside of the chimney I to the wick flame placed
centrally below the said chimney. The air then passes upwards through the chimney I
and gauze cylinder J, through the chamber formed by the upper half L' of the
shield Land passes out of the lamp through the opening in the conical top L' of the
shield L.
The lamp can be made any desired size and the dimensions of the various parts can
be varied.
The following dimensions have been found most suitable, a lamp made to these
dimensions having been tested and could not be exploded in a five minutes test, the
velocity being equal to 50 feet per second. Total height of lamp eight and a half
inches, and diameter averaging three inches. Glass cylinder A two inches in diameter
and two inches high, the oil vessel projecting two inches below the glass cylinder ;
collar-ring H just under one inch and a quarter above the glass cylinder A. The
gauze cylindrical cap J two inches and a quarter high, and the chimney I one and a
half inches long below its flange 1'. The upper half L' of the shield L two and a
quarter inches long and its lower half L³ two inches long from its bottom to the
shoulder at top, the inlet holes punched therein being one inch above the turned-out
edge I at bottom of upper half L'. The conical top L² attached to the top of the
upper half L' is about seven-eighths of an inch high, and the outlet aperture in the
said conical top is half an inch in diameter. The top P is supported about three-
eighths of an inch above the conical top L' of the shield L.

page_text: The shield L and pillar lock T may be applied to other miners' lamps, principally
the Clanny, Meuseler, and Marsaut lamps, the shield L being used combined with the
pillar lock T or each separately. Where the shield L is not used with the pillar lock T,
the said shield is rivetted securely to the upper ring C of the lamp frame, the screw
ring M being dispensed with. It may be found necessary in adapting the shield to
the before-mentioned lamps to have the inlet holes in the lower half L³ of the shield L
only about one quarter of an inch above the turned-out edge L of the upper half of
the shield L, the shut-off band being made shorter also. The outlet aperture in
the conical top L² of the shield L may also have to be larger in diameter.
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 :-
First In a miners' safety lamp, the combination of the shield L, the collar-ring H,
chimney I, gauze cylindrical cap J and screw ring K, substantially in the manner
herein set forth.
Second In a miners' safety lamp, the collar-ring H with its inner flange H³,
screw thread H³ and grooves й*, the screw ring K, chimney I with its attached
flange l' and the gauze cylinder J combined and arranged substantially as herein set
forth.
Third-In a miners' safety lamp, the shield L consisting of the conical top L³,
upper half L with lower turned-out end L, and the lower half I constructed and
arranged substantially as herein set forth.
Fourth In a miners' safety lamp, the pillar lock T, constructed and arranged
substantially as and for the purpose herein set forth.
Fifth In a miners' safety lamp, the picker V with horizontal portion V¹, curved
portion V2 and tongue V³ constructed substantially as herein set forth.
Sixth In a miners' safety lamp, the combination of the screw lock S and collar
ring Fattached to the ring plate F, substantially in the manner and for the purpose
herein set forth.
Dated this 21st day of December A.D. 1887.