IMPROVEMENTS IN MINERS' SAFETY LAMPS
Year: 1883

page_text: LETTERS PATENT to Jasper Wetter, of New Wandsworth, Surrey, for an
Invention of IMPROVEMENTS IN MINERS' SAFETY LAMPS communicated to him
from abroad, by H. Friemann, of Eisleben, in the German empire
PROVISIONAL SPECIFICATION left by the said Jasper Wetter at the Offico
of the Commissioners of Patents on the 23rd June 1883.
JASPER WETTER, of New Wandsworth, Surrey, "IMPROVEMENTS IN MINERS'
SAFETY LAMPS" n communication to me from abroad by H. Friemann, of Eisleben,
in the German empire,
This invention relates to the application of volatile hydrocarbons in safety
lamps, and to the construction of some devices which prevent the improper
opening of the lamp, but allow the workman, when the lamp is extinguished, to
light it again without opening the lamp.
In order to prevent the explosion of light hydrocarbons, when used in safety-
lamps, the whole oil-receptacle is filled with absorbent material, such as wadding
or fossil meal, into which dips the wick-tube, made vertically adjustable from
below by means of a small screw-spindle. The wick tube is mounted inside the
receptacle and surrounded, at some distance from the wick-tube, by another
tube provided with slots and openings, while the upper extremity of the wick tubo
is tightly surrounded by a screw-cap which closes the receptacle. If the wick is
screwed up too high the vapours formed by the increased temperature prevent
the external air from entering through the wire-netting of the lamp, thereby
depriving the flame of the air necessary for combustion, before the soot deposited
on the wire-netting has caught fire.
The device for lighting the lamp.may be as follows:
An annular capsule, placed inside the glass-cylinder, and surrounding the top
of the wick tube, contains a fuze or match-tape. A pin or axle passing through
the receptacle and adapted to be turned from below, carries at its top a small cam
or toothed disc, which, when turned, propels the match-tape or fuze along a guide,
so as to place the latter before a small capsule terminating at the upper extremity

page_text: of the wick, while the same turning of the axle sets a small coiled spring in
tension. By the furthor turning of the axle the said spring is released and
allowed to strike against the tape, so as to ignite a small quantity of explosive or
inflammable substance carried by the said tape. The spark thus produced in the
small capsule is guided to the top of the wick and ignites the latter.
Another form of igniting apparatus consists chiefly of a casing having the shape
of an upright shuttle and provided with lateral slots for guiding a slide capable
of being moved up and down by means of an upright rod, while the top of the slide
carries a moveable cam. The closed back of the casing serves to guide the igniting
tape, a predetermined length of which is moved upward or fed at every upmotion
of the slide, by means of a spring. The casing carries also a strong spring
provided with two slots which extends upward in' the shape of a hammer, the
said spring being set in tension at every up motion of the slide by means of the
said cam.
The continued upmotion of the slide places the cam opposite the upper
slot of the spring, and allows the latter to strike against the match-tape, so as to
ignite a portion of the same. The device for locking the lid or preventing the
improper opening of the oil receptacle comprises a casing, secured to the lid, and
enclosing a pawl the beak of which fits into recesses applied to the circumference
of the oil receptacle; a double armed lever pivoted on its centre of gravity &
moveable inside the casing (preferably in a plane perpendicular to the motion of the
pawl) and a light spring adapted to hold one arin of the said lever between the
said pawl and the casing, so as to prevent the pawl from moving outward, while
the double armed lever is prevented from turning, by the contact of the pawl with
a lateral projection of the lever. In order to open the oil receptacle the beak of
the pawl is turned inward by applying a key to its axle (so as to advance in one
of the recesses as far as possible), thereby removing the pawl from the lateral
projection of the double armed lever; whereupon the latter is turned out of the
way by means of a magnet, and the pawl is released from its notch by turning
the key in the opposite direction, after which the lid of the receptacle may be
opened

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Jasper Wetter in the Great Seal Patent Office on the 22nd December
1883.
JASPER WETTER, of New Wandsworth, Surrey, "IMPROVEMENTS IN MINERS'
SAFETY LAMPS," a communication to ine from abroad by H. Friemann, of Eisleben,
in the German empire
This invention relates to the application of volatile hydrocarbons in safety
lamps, and to some devices which prevent the workman from unnecessarily opening
the lanp, but allow him, when the lamp is extinguished, to light it again without
opening the lamp.
In safety lamps hitherto employed in mines and for similar purposes, heavy
oils or even fat have been used, the application of which excludes beforehand any
explosion of the oil. This great advantage is, however, more than outweighed by
the following drawback.
If the wick is too high, so as to cause an incomplete combustion, together with a
strong deposit of soot, the latter accumulates in a thick layer on the wire netting.
The lamp continues to burn for some time with a larger flaine which soon causes
this layer of soot to become incandescent, thereby sufficiently licating the wire
netting to cause the ignition of any fire damp which may be present.
The application of volatile hydrocarbons, for instance benzine, prevents the
explosion of fire damp in a peculiar manner.
If a volatile hydrocarbon, such as benzine, is employed, and if the wick is too
high, the temperature of the receptacle containing the benzine rises considerably,
so as to cause an abundant generation of benzine vapours which prevent the air
necessary for combustion to enter through the wire netting from above, in conse-
quence of which the flame is extinguished in a short time. Although in this case
also considerable quantities of soot are deposited, the time during which the
formation of soot takes place, is not sufficiently long to cause the ignition of the
thin layer of soot deposited on the wire netting.
If hitherto no volatile fuel or illuminant has been employed for this purpose it
was owing to the fear of explosions similar to those of petroleum lamps.
Explosions of this kind may, however, be prevented by a special construction of
the benzine receptacle.
A further improvement in safety lamps also consists in the application of a device
operated from without for relighting the lamp when the same has been extinguished
by a draught of wind.
In the accompanying drawing Fig. 1 represents a safety lamp embodying this
invention.
In order to prevent an explosion in the lamp, the whole receptacle E is filled
with absorbent material, such as wadding or certain kinds of earth (fossil meal),
and into this receptacle extends a wick-tube H, made of wire netting or gauze, and
adjustable in height by means of a screw spindle F. The wick-tube is surrounded
inside the receptacle by another tube provided with slots or other openings, and is
tightly enclosed at the top by a cap b. By keeping the receptacle always filled
and preventing the accumulation of vapours, explosions in the lamp are avoided..
Inside the glass-cylinder B is secured to the cap b an igniting apparatus
represented in detail by Figs. 2, 3, 4 and 5, of which Figs. 2 and 4 are vertical

page_text: sections of the apparatus in different positions or stages of operation, while Fig. 3 is
a front elevation of the whole igniting mechanism and Fig. 5 an elevation of a part
of the same.
The igniting mechanism comprises a casing a having the shape of a loom-shuttle,
and which is provided with Interal slots b adapted to guide a slide d. This slide
carries at the top a movable thumb. f.
The closed back of the casing serves to guide the match-tape c which is moved
upward by the spring h for a distance depending on the distance (from each other)
of the explosive charges m carried by the said tape, whenever the slide d is pressed
upward.
The casing a also contains a strong spring k provided with slots. i. and i¹ and
formed at the top into a hammer. In the lowest position of the slide d (Fig. 3)
the thumb. projects through the slot i and allows the spring to press with its
upper end against the upper extremity of the casing a.
By the upward motion of the slide the match-tape is first shifted upward and
the spring set in tension by means of the thumb f, as shown in Fig. 2.
The continued lifting of the slide causes the thumb to fall into the slot i,
whereupon the spring k strikes against an explosive charge m and ignites the same.
It is evident that the mechanism for lighting the lamp from outside may be
varied without changing the result.
A further feature of novelty consists in the inproved construction of magnetic
locks which prevents the improper opening of the lamp.
This lock, which is represented. by Figs 6 and 7 of the drawing, comprises the
casing A secured to the screw-cap or upper ring F of the lamp and containing a
double armed lever b pivoted on a pin a, which passes through the centre of gravity
of the lever b, so as to prevent any tendency to an accidental turning of the lever
in consequence of vibrations or shucks.
The arm bof this lever has at its end a small projection c, adapted to afford a
rest for the pawl C when-the lamp. is. closed. This pawl is pivoted on the pin e
and projects with its heak C into one of the notches E cut into the screw-thread at
the circumference of the oil receptacle. G.
This pawl C thus prevents the screw-cap or ring F. from being screwed off, and
is kept in its locking position by the double armed lever b. In this position the
turning of bis prevented by the projection c of the pawl, which abuts against the
lever b from below.
The unlocking of the lid F is effected in the following manner:
A key D is applied to the square portion of the pine projecting over the lid F,
and by turning the key the beak C¹ of the pawl is pressed into the notch E of the
receptacle G until the pawl has come out of contact with the projection c of the
lever b. Sul sequently a strong magnet N S is approached to the casing and moved
so as to turn the lover bb away from pawl C. Subsequently the beak of the pawl
is lifted out of the notch E by turning the key D, after which the lid F be
may
screwed off.
Having now described the invention and in what manner the same is to be
performed I wish it to be understood that I do not limit myself to the precise
details shown by the drawings, as the same may be modified without departing
from the invention, but that what I claim is :
In miners' safety lamps:
1. The use of volatile fuel or illuminant in combination with suitable absorbent
material in the manner substantially as and for the purpose described.
2. The use of igniting mechanism adapted to be operated from outside for the
purpose of lighting the lamp without opening the same, substantially as
described.
3. The closing or locking mechanism for safety lamps, which comprises in its
construction a pawl placed inside a casing and adapted to take into notches

page_text: provided in the oil-receptacle, a double armed lever pivoted at or near its centro
of gravity, the said pawl and lever being adapted to secure each other in their
locking position in the manner substantially as described.
In Witness whereof I, the said Jasper Wotter have hereunto set my hand and
seal this 22nd day of December A.D. 1883.