IMPROVEMENTS IN SAFETY LAMPS
Year: 1886

page_text: Date of Application, 26th Mar., 1886.
Complete Left, 23rd Dec., 1886.
Complete Accepted, 25th Jan., 1887.
1 MAUNSELL MERCIER of Highfield near Wigan in the County of Lancaster, Mining
Engineer do hereby declare the nature of invention for "IMPROVEMENTS IN SAFETY
LAMPS" to be as follows:--
My lamp is an improvement upon safety lamps and has for its objects the extinguish-
ing of the lamp when in an explosive atmosphere, the use of the same for the purpose
of shot-firing and testing for gas and the extinction of the light by the action of
unlocking the lamp. The gauzes are arranged as in an ordinary Davy lamp, and the
lamp has a chimney somewhat similar to the one generally used in Mueseler lamps.
The gauzes are fixed to the lamp bottom by a brass ring to which is also attached the
chimney. Where the upper and lower gauzes join I place a brass disc perforated
with small holes and attach the same also to the chimney which passes through the
centre, and this disc has two flanges one at the top and the other at the bottom to
which are attached the two gauzes in such a manner as to form an air-tight joint.
Above this disc is a second disc but not perforated attached to the chimney and within
the gauze. This disc prevents the air from passing into the top gauze without first
passing through the perforated disc and up the chimney thereby keeping the inlet and
outlet currents of air distinct and seperate from each other and compels the current to
pass down through the holes of the perforated disc thereby feeding the flame of the
lamp in the manner hereafter referred to. The upper part of the gauze is surrounded
by two cylinders concentric with each other (and having an interspace sufficiently
large to admit of the passage of a sliding glass tube) made of tin or other metal and
fastened to the standards and top of the lamp. This glass tube rests upon the seating
outside the gauze and is allowed to slide freely up the interspace between the two
cylinders. The flame of the lamp is fed by air coming from the top of the lamp
through the interspace between the two cylinders and obtains entrance into the lamp
through perforations in the inner cylinder slightly above the disc containing the
perforations above referred to and between that position and the solid disc also
mentioned. The products of combustion pass by the interior of the chimney through
the gauze
at the top of the lamp. When the glass is down and resting upon the
seating of the lamp, the lamp is safe, as the light will be extinguished when in the

page_text: presence of gas but if it is desirable to use the lamp for shot-lighting purposes or for
testing for gas the glass cylinder may be raised into the metal cylinder and the flame
fed through the lower portion of the gauze as in the ordinary Davy Lamp. The lock
consists of an eccentric lever or bow which is attached to a cup or cap. This lever
works on centres in supports fastened to the lamp bottom and is connected with a
semi-circular lever or arm at the end of which is a tooth so placed that when the lamp
is locked it is under a bracket. A bolt is then pushed through a hole cast on the base
of the lamp. At the end of this bolt is a tooth corresponding to the one attached to
the semi-circular lever but the reversed way up so that when the bolt is pushed
forward both of the teeth are under the bracket and locked together and before they
can be separated the bolt must be partly withdrawn in doing which the lever is pulled
with it, and as this lever turns on its centre the cap or cup attached to and actuated
by this lever extinguishes the light. So soon as the teeth are drawn clear of the
bracket, they will slide apart and so allow the lamp to unlock or unscrew. In the
bolt and in the casting through which the bolt works there is provision made to allow
of the lamp being additionally locked by means of the ordinary padlock or lead rivet,
which can pass through a hole in the bolt and casting and through a lug on the oil
vessel or bottom of the lamp.

page_text: I MAUNSELL MERCIER of Enfield Street Highfield near Wigan in the County of
Lancaster Mining Engineer do hereby declare the nature of my invention for
IMPROVEMENTS IN SAFETY LAMPS and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
I use two gauzes (A A¹) joined in the middle by two angle metal rings (B B¹)
which are fastened to the gauzes by placing the smaller end (6 6¹) of the rings (B B¹)
in the gauze then placing closely fitting metal rings (CC) on the outside of the gauzes,
or I use metal wire to lap round the outside of the gauze in lieu of the metal
rings (CC). In the middle of my gauzes and resting upon the seating formed by the
base of the lower ring (B¹) I place a metal chimney (C), this chimney is secured by a
dise (D) of metal perforated with holes or apertures or by a disc of ordinary wire
gauze secured to the chimney (C) and resting on the before-mentioned seating, or I
use instead of these two angle metal rings (B B¹) a solid turned metal ring (Fig. 2)
flanged on the top (Fig. 2 B) and bottom (Fig. 2 C) which flanges fit inside my
gauzes (A A¹); inside the ring Fig. 2 there is left a shoulder of metal (Fig. 2 a) on
which my disc of perforated metal (D) or gauze (D¹) rests, and I fasten these discs by
placing a ring of inctal fitting closely against the sides of this metal ring on the top
of my metal or gauze disc which secures the dise and chimney in position or I
accomplish the same purpose by screwing the ring in. These rings (B B¹) or solid
metal ring (Fig. 2) also make a close joint against the sides of my glass cylinder (E)
which moves up and down still keeping a tight joining to the flanges of the
rings (B B). My lower gauze (A¹) is fastened into a brass ring (F) that screws in
the ordinary way into the bottom collar of the lamp top and tightens the joint of the
metal ring (B B) and forms the seating upon which my glass cylinder (E) rests. This
gauze (A¹) can be secured to the screw ring (F) by means of screws passing through
the flange of the ordinary gauze ring (F¹) (that fits into the gauze (A')) into the screw
ring (F) or it can be held in position by being soldered in. Above my horizontal
metal or gauze disc (D) and attached to the chimney (C) I place the second metal.
disc (G) but not perforated-this disc (G) fits the upper gauze (A) closely. Its
purpose is to prevent the air from passing upwards out of the gauze (A) without first
passing through the perforated metal or guze disc (D) into the lower gauze (A') and
up the chimney (C) thereby separating my inlet and outlet currents of air and to
give a more perfect combustion. The upper gauze (A) is surrounded by two
cylinders (HH) concentric with each other (and having an interspace sufficiently large
to admit of the passage of a sliding glass (E) tube or cylinder) made of tin, iron or
other metal or material and fastened to the standard (I) or lamp-top or can be used
loose. The glass tube (E) or cylinder rests upon the scating (formed by the before-
mentioned screw ring (F)) outside the lower gauze (A') and is allowed to slide freely
up the interspace between the two cylinders (H H¹). The flame of the lamp is fed by
air entering the top of the lamp and passing down between the shields (H H') and
obtains entrance into the gauzes (A A¹) through holes in the inner cylinder (H')
slightly above the disc of perforated metal or gauze (1)¹) above referred to, and

page_text: between that position and the solid disc (G) (as shewn by the arrows with tails
attached) then passing through the metal or gauze disc (I)') into the lower gauze (A¹)
to the flame.
The products of combustion pass by the interior of the chimney (C) through the
gauze (A) and holes in the top of the lamp (J) (as shown by the arrows without tails.
When the glass (E) is down and resting upon its seating the lamp is safe as the light
will be extinguished when in an explosive atmosphere. But if it is required to use
the lamp for shot firing or testing for gas, the glass cylinder (E) may be raised and
the lamp fed thro' the lower portion of the gauze (A¹) as in the ordinary Davy
lamp.
cup
The lock consists of an eccentric lever or bow (K) which is attached to a or
cap (K) fastened to the bow (K) or cast as a part of crown of the bow (K). This
lever (K) works on centres (a) in supports (e) fastened to the lampbottom (L) and
is connected with a semi-circular lever or bow (M) fitting partly round the oil
ring (N) of the lamp bottom (L) at the end of which is a tooth (f) so placed that
when the lamp is locked it is under a bracket (9) fastened to the lamp bottom (L) or
formed by securing two studs to the lamp bottom and using the lamp tops lower ring
as a crown. A bolt (0) is then pushed thro' a hole (P) cast or otherwise secured by
soldering or riveting on the base of the lamp-tops lower ring (Q). At the end of this
bolt (0) is a tooth (f¹) corresponding to the tooth (f) attached to the semi-circular
lever (M) but the reversed way up so that when the bolt (O) is pushed forward, both
of the teeth (f) are under the bracket or bridge (g) before referred to and locked
together; the sides of the bracket or bridge (9) prevent the teeth (ff') drawing apart
whilst the lamp is locked; or, if the bracket or bridge (9) be not used a small
stud (g) is fastened to the lamp bottom beside the tooth (f) on the semi-circular
lever (M) so that when the bolt (0) is pushed in it prevents their sliding apart in the
same manner as would the sides of the bridge or bracket (g). Before these
teeth (ff¹) can be separated the bolt (0) must be partly withdrawn, in doing which
the lever (M) is pulled with it by means of the teeth (ff¹) and as this lever (M)
turns on its centres (a. a.) it extinguishes the light by placing the cap or cup (K') over
and above the top of the wick tube (R). So soon as the teeth (f) are drawn clear
of the bracket (g) or stud (g) they will slide apart by partly turning round the lamp-
bottom or oil-vessel (L) and so allow the bolt (0) to be withdrawn when the lamp
can be unscrewed. On the end of the semi circular lever (M) I fasten a spring (S)
by means of screws, rivets or solder and in the form & position as shewn in drawing.
This spring causes the teeth (ff¹) to press together should the lamp be turned upside
down; or the same purpose can be effected by making the top of my bridge (9) of
some elastic metal that will spring when the teeth (ff) are pushed together such as
ordinary watch springs. In the bolt (0) and in the casting (P) thro' which the bolt
works there is provision made to allow of the lamp being additionally locked by the
ordinary padlock or lead rivet (T) which can pass thro' a hole in the bolt (O) &
casting (P) and through a lug (U) fastened on the oil vessel (L). I also use a bent
wire (V) to prevent the wick (Y) being pushed above a certain height above the top
of the burner or wick tube (R); this wire (V) is secured to the burner (R) by
passing thro' a small tube (W) secured to the burner (R) and shilling by
soldering or riveting; this tube (W) comes nearly to the top of the burner (R). The
wire (V) is bent over at the top as shewn in drawing to allow of its being drawn
down by the prickles wire (V¹) and is also bent at the lower end so as to hook into the
wick (Y). As the wick (Y) is raised by the prickles wire (V¹) this pin (V) rises also
and when above the top of the burner (R) the lamp cannot be unlocked until the
wire (V) is drawn down when the wick is also lowered with it. When the wire (V)
is above the burner (R) it prevents the cap (K¹) passing over the burner (R) until
the wire (V) is lowered.
To further illustrate my invention I have above described I have set out the
different views of the same and of the parts thereof in drawings hereunto annexed &
have designated the figures as follows
Fig. 1 is a view of the lamp in elevation, locked and ready for use.

page_text: Fig. 2 shews a sectional view of the solid ring that may be used instead of the
ordinary box or angle rings (B B¹).
Fig. 3 is a sectional elevation of Fig. 1.
Fig. 4 is a sectional elevation of the bottom shewing the action of check wire in
preventing the withdrawal of the bolt when the wick is too high.
Fig. 5 is a plan of the lamp bottom showing the lamp locked.
Fig. 6 is a plan of the lamp bottom shewing position of levers & bolt when the
lamp is unlocked.
Fig. 7 is a section of the lamp bottom shewing position of levers and bolt when the
lamp is unlocked and burner covered over.
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. The method of attaching fastening or securing the gauzes in the manner herein-
before described & illustrated in the accompanying drawings.
2. The use of the rings for the purpose of preventing the air from passing between
the circular glass shield and the gauze thereby causing the air to be admitted for the
purpose of combustion above the rings as shewn by the arrows in the drawings.
3. The supporting of the chimney on the base of the rings connecting the gauzes
and the form of the rings as shewn in drawings.
4. The use of the moveable glass shield working between an outer & inner
shield of metal, and the arrangement of the shields to admit the air for the support of
combustion at the top of the lamp through holes in the outer case or shield as shewn
by the arrows in the accompanying drawings.
5. The arrangement of the levers' cap & bolt in the lock of the lamp for the purpose
of extinguishing the light in unlocking the lamp as illustrated and shewn in the
accompanying drawings.
6. The check wire to prevent the raising of the wick above a fixed height and its
arrangement to prevent the unlocking the lamp when the wick is above the top of
burner.
7. The general arrangement of the lamp in the manner & for the purpose herein-
before substantially shewn & described.
MAUNSELL MERCIER.

page_text: I MAUNSELL MERCIER of Highfield near Wigan in the County of Lancaster, Mining
Engineer do hereby declare the nature of invention for "IMPROVEMENTS IN SAFETY
LAMPS" to be as follows
My lamp is an improvement upon safety lamps and has for its objects the extinguish-
ing of the lamp when in an explosive atmosphere, the use of the same for the purpose
of shot-firing and testing for gas and the extinction of the light by the action of
unlocking the lamp. The gauzes are arranged as in an ordinary Davy lamp, and the
lamp has a chimney somewhat similar to the one generally used in Mueseler lamps.
The gauzes are fixed to the lamp bottom by a brass ring to which is also attached the
chimney. Where the upper and lower gauzes join I place a brass disc perforated
with small holes and attach the same also to the chimney which passes through the
centre, and this disc has two flanges one at the top and the other at the bottom to
which are attached the two gauzes in such a manner as to form an air-tight joint.
Above this disc is a second disc but not perforated attached to the chimney and within
the gauze. This disc prevents the air from passing into the top gauze without first
passing through the perforated disc and up the chimney thereby keeping the inlet and
outlet currents of air distinct and separate from each other and compels the current to
pass down through the holes of the perforated disc thereby feeding the flame of the
lamp in the manner hereafter referred to. The upper part of the gauze is surrounded
by two cylinders concentric with each other (and having an interspace sufficiently
large to admit of the passage of a sliding glass tube) made of tin or other metal and
fastened to the standards and top of the lamp. This glass tube rests upon the seating
outside the gauze and is allowed to slide freely up the interspace between the two
cylinders. The flame of the lamp is fed by air coming from the top of the lamp
through the interspace between the two cylinders and obtains entrance into the lamp
through perforations in the inner cylinder slightly above the disc containing the
perforations above referred to and between that position and the solid disc also
mentioned. The products of combustion pass by the interior of the chimney through
the gauze at the top of the lamp. When the glass is down and resting upon the
seating of the lamp,. the lamp is safe, as the light will be extinguished when in the

page_text: presence of gas but if it is desirable to use the lamp for shot-lighting purposes or for
testing for gas the glass cylinder may be raised into the metal cylinder and the flame
fed through the lower portion of the gauze as in the ordinary Davy Lamp. The lock
consists of an eccentric lever or bow which is attached to a cup or cap. This lever
works on centres in supports fastened to the lamp bottom and is connected with a
semi-circular lever or arm at the end of which is a tooth so placed that when the lamp
is locked it is under a bracket. A bolt is then pushed through a hole cast on the base
of the lamp. At the end of this bolt is a tooth corresponding to the one attached to
the semi-circular lever but the reversed way up so that when the bolt is pushed
forward both of the teeth are under the bracket and locked together and before they
can be separated the bolt must be partly withdrawn in doing which the lever is pulled
with it, and as this lever turns on its centre the cap or cup attached to and actuated
by this lever extinguishes the light. So soon as the teeth are drawn clear of the
bracket, they will slide apart and so allow the lamp to unlock or unscrew. In the
bolt and in the casting through which the bolt works there is provision made to allow
of the lamp being additionally locked by means of the ordinary padlock or lead rivet,
which can pass through a hole in the bolt and casting and through a lug on the oil
véssel or bottom of the lamp.

page_text: Improvements in Safety Lamps.
I MAUNSELL MERCIER of Enfield Street Highfield near Wigan in the County of
Lancaster Mining Engineer do hereby declare the nature of my invention for
IMPROVEMENTS IN SAFETY LAMPS and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
I use two gauzes (A A¹) joined in the middle by two angle metal rings (B B¹)
which are fastened to the gauzes by placing the smaller end (6 6¹) of the rings (B B¹)
in the gauze then placing closely fitting metal rings (CC) on the outside of the gauzes,
or I use metal wire to lap round the outside of the gauze in lieu of the metal
rings (CC). In the middle of my gauzes and resting upon the seating formed by the
base of the lower ring (B¹) I place a metal chimney (C), this chimney is secured by a
disc (D) of metal perforated with holes or apertures or by a disc of ordinary wire
gauze secured to the chimney (C) and resting on the before-mentioned seating, or I
use instead of these two angle metal rings (B B¹) a solid turned metal ring (Fig. 2)
flanged on the top (Fig. 2 B) and bottom (Fig. 2C) which flanges fit inside my
gauzes (A A'); inside the ring Fig. 2 there is left a shoulder of metal (Fig. 2 a) on
which my disc of perforated metal (D) or gauze (D¹) rests, and I fasten these discs by
placing a ring of metal fitting closely against the sides of this metal ring on the top
of my metal or gauze disc which secures the disc and chimney in position or I
accomplish the same purpose by screwing the ring in. These rings (B B¹) or solid
metal ring (Fig. 2) also make a close joint against the sides of my glass cylinder (E)
which moves up and down still keeping a tight joining to the flanges of the
rings (B B¹). My lower gauze (A') is fastened into a brass ring (F) that screws in
the ordinary way into the bottom collar of the lamp top and tightens the joint of the
metal ring (B B¹) and forms the seating upon which my glass cylinder (E) rests. This
gauze (A) can be secured to the screw ring (F) by means of screws passing through
the flange of the ordinary gauze ring (F) (that fits into the gauze (A')) into the screw
ring (F) or it can be held in position by being soldered in. Above my horizontal
metal or gauze disc (D¹) and attached to the chimney (C) I place the second metal
disc (G) but not perforated-this disc (G) fits the upper gauze (A) closely. Its
purpose is to prevent the air from passing upwards out of the gauze (A) without first
passing through the perforated metal or gauze disc (D) into the lower gauze (A') and
up the chimney (C) thereby separating my inlet and outlet currents of air and to
give a more perfect combustion. The upper gauze (A) is surrounded by two
cylinders (HH) concentric with each other (and having an interspace sufficiently large
to admit of the passage of a sliding glass (E) tube or cylinder) made of tin, iron or
other metal or material and fastened to the standard (I) or lamp-top or can be used
loose. The glass tube (E) or cylinder rests upon the seating (formed by the before-
mentioned screw ring (F)) outside the lower gauze (A') and is allowed to slide freely
up the interspace between the two cylinders (H H¹). The flame of the lamp is fed by
air entering the top of the lamp and passing down between the shields (H H¹) and
obtains entrance into the gauzes (A A¹) through holes in the inner cylinder (H')
slightly above the disc of perforated metal or gauze (D¹) above referred to, and

page_text: between that position and the solid disc (G) (as shewn by the arrows with tails
attached) then passing through the metal or gauze disc (D') into the lower gauze (A¹)
to the flame.
The products of combustion pass by the interior of the chimney (C) through the
gauze (A) and holes in the top of the lamp (J) (as shown by the arrows without tails.
When the glass (E) is down and resting upon its seating the lamp is safe as the light
will be extinguished when in an explosive atmosphere. But if it is required to use
the lamp for shot firing or testing for gas, the glass cylinder (E) may be raised and
the lamp fed thro' the lower portion of the gauze (A¹) as in the ordinary Davy
lamp.
The lock consists of an eccentric lever or bow (K) which is attached to a cup or
cap (K) fastened to the bow (K) or cast as a part of crown of the bow (K). This
lever (K) works on centres (a) in supports (e) fastened to the lampbottom (L) and
is connected with a semi-circular lever or bow (M) fitting partly round the oil
ring (N) of the lamp bottom (L) at the end of which is a tooth (f) so placed that
when the lamp is locked it is under a bracket (g) fastened to the lamp bottom (L) or
formed by securing two studs to the lamp bottom and using the lamp tops lower ring
as a crown. A bolt (0) is then pushed thro' a hole (P) cast or otherwise secured by
soldering or riveting on the base of the lamp-tops lower ring (Q). At the end of this
bolt (0) is a tooth (f') corresponding to the tooth (f) attached to the semi-circular
lever (M) but the reversed way up so that when the bolt (0) is pushed forward, both
of the teeth (ff) are under the bracket or bridge (g) before referred to and locked
together; the sides of the bracket or bridge (g) prevent the teeth (ff¹) drawing apart
whilst the lamp is locked; or, if the bracket or bridge (9) be not used a small
stud (g) is fastened to the lamp bottom beside the tooth (f) on the semi-circular
lever (M) so that when the bolt (0) is pushed in it prevents their sliding apart in the
same manner as would the sides of the bridge or bracket (g). Before these
teeth (f) can be separated the bolt (0) must be partly withdrawn, in doing which
the lever (M) is pulled with it by means of the teeth (ff¹) and as this lever (M)
turns on its centres (a. a.) it extinguishes the light by placing the cap or cup (K¹) over
and above the top of the wick tube (R). So soon as the teeth (ff¹) are drawn clear
of the bracket (g) or stud (g¹) they will slide apart by partly turning round the lamp-
bottom or oil-vessel (L) and so allow the bolt (0) to be withdrawn when the lamp
can be unscrewed. On the end of the semi circular lever (M) I fasten a spring (S)
by means of screws, rivets or solder and in the form & position as shewn in drawing.
This spring causes the teeth (ff¹) to press together should the lamp be turned upside
down; or the same purpose can be effected by making the top of my bridge (g) of
some elastic metal that will spring when the teeth (ff) are pushed together such as
ordinary watch springs. In the bolt (0) and in the casting (P) thro' which the bolt
works there is provision made to allow of the lamp being additionally locked by the
ordinary padlock or lead rivet (T) which can pass thro' a hole in the bolt (O) &
casting (P) and through a lug (U) fastened on the oil vessel (L). I also use a bent
wire (V) to prevent the wick (Y) being pushed above a certain height above the top
of the burner or wick tube (R); this wire (V) is secured to the burner (R) by
passing thro' a small tube (W) secured to the burner (R) and shilling by
soldering or riveting; this tube (W) comes nearly to the top of the burner (R). The
wire (V) is bent over at the top as shewn in drawing to allow of its being drawn
down by the prickles wire (V¹) and is also bent at the lower end so as to hook into the
wick (Y). As the wick (Y) is raised by the prickles wire (V) this pin (V) rises also
and when above the top of the burner (R) the lamp cannot be unlocked until the
wire (V) is drawn down when the wick is also lowered with it. When the wire (V)
is above the burner (R) it prevents the cap (K') passing over the burner (R) until
the wire (V) is lowered.
To further illustrate my invention I have above described I have set out the
different views of the same and of the parts thereof in drawings hereunto annexed &
have designated the figures as follows
Fig. 1 is a view of the lamp in elevation. locked and ready for use.

page_text: Fig. 2 shews a sectional view of the solid ring that may be used instead of the
ordinary box or angle rings (B B¹).
Fig. 3 is a sectional elevation of Fig. 1.
Fig. 4 is a sectional elevation of the bottom shewing the action of check wire in
preventing the withdrawal of the bolt when the wick is too high.
Fig. 5 is a plan of the lamp bottom showing the lamp locked.
Fig. 6 is a plan of the lamp bottom shewing position of levers & bolt when the
lamp is unlocked.
Fig. 7 is a section of the lamp bottom shewing position of levers and bolt when the
lamp is unlocked and burner covered over.
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 I do not claim any
part of the invention comprised in and described by the specification of the Patent of
Andrew Howat No. 1709 of the year 1886, but what I claim is
1. The method of attaching fastening or securing the gauzes in the manner herein-
before described & illustrated in the accompanying drawings.
2. The use of the rings for the purpose of preventing the air from passing between
the circular glass shield and the gauze thereby causing the air to be admitted for the
purpose of combustion above the rings as shewn by the arrows in the drawings.
3. The supporting of the chimney on the base of the rings connecting the gauzes
and the form of the rings as shewn in drawings.
4. The use of the moveable glass shield working between an outer & inner
shield of metal, and the arrangement of the shields to admit the air for the support of
combustion at the top of the lamp through holes in the outer case or shield as shewn
by the arrows in the accompanying drawings.
5. The arrangement of the levers' cap & bolt in the lock of the lamp for the purpose
of extinguishing the light in unlocking the lamp as illustrated and shewn in the
accompanying drawings.
6. The check wire to prevent the raising of the wick above a fixed height and its
arrangement, to prevent the unlocking the lamp when the wick is above the top of
burner.
7. The general arrangement of the lamp in the manner & for the purpose herein-
before substantially shewn & described.