IMPROVEMENTS IN AND CONNECTED WITH ELECTRIC LAMPS
Year: 1879

page_text: LETTERS PATENT to George Guillaume André, of Dorking, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN AND CONNECTED WITH
ELECTRIC LAMPS."
Sealed the 22nd August 1879, and dated the 1st March 1879.
PROVISIONAL SPECIFICATION left by the said George Guillaum André at
the Office of the Commissioners of Patents on the 1st March 1879.
George GuillauME ANDRÉ, of Dorking, in the County of Surrey. "IMPROVE-
MENTS IN AND CONNECTED WITH ELECTRIC LAMPS."
A principal object of this Invention is to construct electric lamps which shall be
suitable for lighting mines, but which may also be advantageously applied to other
lighting purposes.
According to one arrangement, I employ a series of thin carbon rods which rest
on a larger piece of carbon or metal, or say, a solid carbon cylinder encased in
metal. The carbon rods are enclosed in tubes to slido easily thereiu, and are lightly
pressed down by sinall loose weights resting on them. By means of a commutator
to be described further on, one of the carbons only is kept in a state of incan-
descence at a time, and when that one from some cause is rendered inoperative, the
next carbon is automatically rendered operative or incandescent. To prevent waste
of the carbons and as regards mines, also to prevent fire damp explosions, I enclose
the carbon rods and other parts in a glass cylinder; as the oxygen therein is
consumed, the rate of wasting of the carbon is gradually lessened, and at last in the
course it may be of an hour, the enclosed atmosphere will consist of nitrogen and
carbonic acid only, and the waste of carbon then becomes very slow. The negativo
pole is connected to the aforesaid lower large piece of carbon or metal, and the
positive poles to the carbon rods. The glass cylinder may be silvered at the top,
and if desired, also on one side to reflect the light as required, or reflectors may be
fitted in or at the top and side. The contacts against the carbon rods are
suspended in hinged brackets or levers. The lamp may be made to stand on a foot
or to be suspended.

page_text: According to another arrangement, I incline one or more couples of positive carbon
rods against a larger central negative carbon rod or slab, so that the outer ends of
the former rest against a piece of metal or carbon or other conductor on the end of
the latter. By screws or other suitable means, the distance between the positive
and negative carbons may be adjusted as required. As the ends of the former
waste away, the voltaic arc changes its position against the negative carbon. When
one of the positive carbons has been consumed, the next one is brought into action
by the commutator.
According to another arrangement, I use a slab or plate of some incombustible
nonconducting substance in combination with one or more couples of carbon rods,
which at one end are inserted in weighted hinged sockets, and the other ends of
which rest and incline against the slab, and the latter is rendered incandescent at
the point where the voltaic arc is produced, and this latter changes its position on
the slab as the carbons are consumed. If more than one couple of carbons are
applied, the commutator will, as in the other cases, throw in connection a fresh
couple after that the first couple has been consumed. For the slab I may use a
combination of clay and lime.
According to another arrangement, I rest two carbon rods on the end of a slab
or bar of nonconducting incombustible material, such as a composition of clay and
lime. The carbons are at their upper ends fixed in holders which are arranged to
slide on the frame or stand. The nonconducting substance fuses and decomposes,
and the carbons drop accordingly with the slab, remaining in contact; the slab is
only slightly thicker than the carbons, and not much wider than twice their
thickness, I thereby ensure an even wasting away of the slab, and that the ends of
the carbons remain exposed and do not bury themselves in the slab. The carbons
may also be placed beneath the slab, and be held against it by any suitable weight
appliances. If more than one couple of carbon rods be used, the aforesaid com-
mutator would be applied.
According to another arrangement, I apply two plates or discs of carbon of the
same size and form, and which at their centres are a greater distance apart than at
their outer edges for the purpose of increasing the resistance towards the middlo.
The narrow space between them may be left empty, but I prefer to apply an
intermediate nonconducting and noncombustible substance or composition which
may consist of clay and lime. The discs or slabs are mounted on a vertical or
horizontal or inclined stem, which at each end is connected to a pole of the electric
'generator. The voltaic arc constantly changes its position on the edges of the
plates or discs, and as the discs wear away gradually approach the centres.
The lamps arrangements last described may, in each case, for the sake of safety
and economy in carbons, be enclosed in glass globes, as described with reference to
the first arrangement.
The commutator is constructed as follows:-I combine two or more electro
magnets with their respective armatures in such a manner that when the connection
to one of the carbons in the lamp is interrupted, the corresponding electro magnet
shall let go its armature, and this then serve to throw the current through the
electro magnet corresponding to the next carbon, thus causing it to light or "burn."
The number of electro magnets is one less than the number or sets of carbons in
connection therewith. Each armature when not attracted forms contact with a
binding screw. Supposing there are four carbons, one of which only is to be alight at
a time, the current passing first through the coils of an electro magnet placed at or
near the middle between and some little distance behind two other electro magnets
which I call the right hand one and the left hand one. The armature of the middle
magnet being attracted will be drawn away from a contact connected to the coil on
the left hand magnet, and the wire connection from the middle magnet to the coil
of the right hand magnet will cause the armature of the right hand magnet to be
attracted, and thus drawn away from the contact in connection with binding screw
for the second carbon from the right. The coil on the right-hand magnet is

page_text: connected to the first carbon on the right. If this latter becomes inoperative, the
armature for the right hand magnet will by its spring be pulled over against the
contact in connection with the second carbon, and no current will pass through the
right hand or left hand electro magnet coils. When the second carbon becomes
inoperative, the armature of the middle magnet is let go, the armature of the
left magnet is attracted, and the current passes through the armature of the middle
magnet through the coils of the left hand magnet, and to the terminal or binding
screw for the third carbon and so on.
The box containing the commutator may be arranged to form the foot of the
lamp, or it may be placed separately in any convenient place.
This commutator may also be applied to other electric lamps, having carbons or
sets of carbons coming successively in operation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Guillaume André in the Great Seal Patent Office on the
1st September 1879.
GEORGE GUILLAUME ANDRÉ, of Dorking, in the County of Surrey.
MENTS IN AND CONNECTED WITH ELECTRIC LAMPS."
"IMPROVE-
A principal object of this Invention is to construct electric lamps which shall be
suitable for lighting mines, but which may also be advantageously applied to other
lighting purposes.
According to one arrangement I employ a series of thin carbon rods which rost
on a larger piece of carbon or metal, or it may be on a corresponding number of
pieces of carbon or metal, or, say, a solid carbon cylinder encased in metal.
Figure 1 of the accompanying Drawings is a side elevation; Figuro 2, a front
elevation; Figure 3, a sectional plan (through A, B, Figure 1); and Figuro 4, a
plan of such an arrangement constructed ospecially for use in mines. a, a, a, a, are
four carbon rods, and b, b, b, b, four copper dises; or instead of four copper discs I
may use a copper cylinder long enough for all four carbon rods to rest thereon.
The carbon rods a are enclosed in tubes A to slide easily therein, and are lightly
pressed down by small loose weights c resting on them. d is an intervening button
or guide piece in which the upper end of the carbon is inserted.
By means of a commutator, to be described further on, one of the carbons a only
is kept in a state of incandescence at a time, and when that one from some cause is
rendered inoperative the next carbon is automatically rendered operative or incan-
descent. To prevent waste of the carbons, and as regards mines also to prevent fire
damp explosions, I enclose the carbon rods a and the parts in a glass cylinder C, as
the oxygen therein is consumed by the combustion of the carbon the rate of wasting
of the latter is gradually lessened, and at last in the course it may be of, say, half
an hour, the enclosed atmosphere will consist of nitrogen and carbonic acid only,
and the waste of carbon then becomes very slow.
The discs bare by a central bar e connected together, and the two outer discs b
are by screws pivotted eccentrically to the bracket or carriage F. The negative
pole is by the bracket F connected to the discs b, as shown in this example, or the
aforesaid lower large piece of carbon or metal and the positive poles to the carbon
rods. The enclosing tubes A are for this purpose connected to the positive pole
through the standards D, and have each at the lower end a lever g, the outer and
heavier end of which serves to press the carbon against the lower part of the tube
A. The part of the lover coming against the carbon is hollowed out so as to partly
embrace it, and thus produce good electrical contact and causing the current to enter
the carbon from both sides. The carbon in gradually burning or wasting away
leaves a silicious deposit on the metal disc or other part on which it rests. This
deposit causes occasional sudden extinction of the light by interrupting the current;
another cause of extinction is the softening to a pasty consistency of the lower part
of the carbon, causing this part to adhere to the tube at the place of contact there-
with. To obviate both these evils I impart at such times a turning action to the
disc b in the following manner :-)
-E is an electro magnetic core with coils round it
connected to the bracket F and one of the outer rods, viz., the one for the return
current. The keeper or armature G of this electro-magnet is fixed to the central
bar e of the discs b; H is a stopper for preventing the armature G from receding
too far from the core E; K is a stopper on the opposite side for preventing the
armature from approaching too near to the electro magnet, and which may, as here
shown, be provided with a coil, also connected to the rod I for the current return,
but shorter than the coil on the core E; thus producing less resistance to tho
current and causing a small part of the current only to act on the electro magnet
after the armature has been attracted.

page_text: When the current passes through the coils of the electro magnet the armature is
attracted, and the carbons are thereby pulled over into good contact with the lower
ends of the tubes. The larger portion of the current is shunted through the stop K.
to the terminal rod I in order to lessen the attractive force of the electro magnet
and to diminish the resistance. In case the current from one of the two aforesaid
causes be interrupted at the place of incandescence the armature G is let go from
the position shown, and a spring h then turns the eccentrically mounted discs
slightly in the direction of the arrow, thus causing the disc to rise a little, whereby
the carbon if stuck will be released, and whereby also any silicious deposit on the
discs will be pushed away by the carbon point.
When the circuit has thus been restored the armature will be attracted again
and the discs thereby be turned into their former position. The glass cylinder C
may be silvered at the top, and if desired also on one side to reflect the light as
required, or reflectors may be fitted in or at the top and side. The lamp may be
made to stand on a foot, as shown, or to be suspended.
According to another arrangement shown in elevation at Figure 5, I incline one
or more positive carbon rods (in this case two rods or slabs A, A,) against a larger
central negative carbon rod or slab, so that the outer ends of the former rest against
a piece of metal or carbon or other conductor on the end of the latter; or I make
the central rod or slab the metal conductor, as here shown; C is the central slab.
By screws a or other suitable means the distance between the positive carbons A, A,
and the negative slab O may be adjusted as required. As the ends of the former
waste away the voltaic are changes its position against the negative slab. When
one of the positive carbons A has been consumed the next one is brought into action
by the commutator, which may be placed in the foot or stand B. This latter also
contains an electro magnet for each carbon and serving to pull the latter out of
contact with the slab for the purpose of establishing the voltaic arc by attaching
an armature, which by a rod b is connected with the carriage c for the carbon rod A,
which carriage pivots on the fulcrum pin d, so that its weight and that of the
carbon tends to throw the latter against the slab C. This latter is hollow from end
to end, as shown by part section, for the circulation of air through it to keep it as
cool as possible. The middle slab C is notched in below at each side in order to
cause an extinction of the voltaic arc when the carbon has burned down to its
socket.
According to another arrangement, shown at Figures 6 and 7, I apply two plates
or discs a and b, of carbon, of the same size and form, and which at their centres
are a greater distance apart than at their outer periphery, as shown in section at
Figure 7, for the purpose of increasing the resistance towards the middle. The narrow
space between them may be left empty, but I may apply an intermediate non-
conducting and non-combustible substance or composition c, which may consist of
clay and line. The discs or slabs are mounted on a vertical stem d (or it might
be an inclined stem), which at each end is connected to a pole of the electric
generator. The voltaic are constantly changes its position on the edges of the
plates or discs, and as the discs wear away, gradually approaches the centre.
The lamp arrangement last described may in each case, for the sake of safety
and economy in carbons, be enclosed in glass globes, as described with reference to
the first arrangement.
The commutator is constructed as follows, and as illustrated in Figures 8 and 9,
of which Figure 8 is a plan and Figure 9 an end view. I combine two or more
(in the case shown here, three) electro magnets A, B, and C, with their respective
armatures a, b, c, in such a manner that when the connection to one of the carbous
in the lamp is interrupted the corresponding electro magnet shall let
go its
armature, and this then serve to throw the current through the electro magnet
corresponding to the next carbon, thus causing it to light or burn. The number
of electro magnets is one less than the number or sets of carbons in connection
therewith, hence the three electro magnets here shown are suitable for use in con-
nection with a lamp having four carbons.

page_text: Each arinature when not attracted forms contact with a pillar A¹, B', C¹, respec-
tively, or other part in electrical connection with the terminals, say, by incans of a
binding screw, as shown. Supposing there are four carbons, one of which only is
to be alight at a time, the current passing first through the coils of an electro
magnet A, placed between two other electro magnets B and C, which I call the
right hand one and the left hand one, the armature a of the middle magnet A
being attracted, will be drawn away from a contact A' connected to the coil on
the left hand magnet C, and the wire connection from the middle magnet A to the
coil of the right hand magnet B will cause the armature b of the right hand
magnet B to be attracted, and thus drawn away from the contact B' in connection
with terminal binding screws for the second carbon from the right.
The coil on the right hand magnet B is connected to the terminal binding screw 1
for the first carbon on the right. If this latter becomes inoperative the armature b
for the right hand magnet B will by its spring b¹ be pulled over against the
contact B in connection with the terminal binding screw 2 connected with the
second carbon, and no current will pass through the right hand or left hand electro
magnet coils B and C respectively. When the second carbon becomes inoperative
the armature a of the middle magnet A is let go and comes against the contact A¹.
The armature c of the left magnet C is then attracted and the current passes
through the armature a of the middle magnet A through the coils of the left band
magnet C and to the terminal or binding screw 3 for the third carbon, and so on.
Instead of springs a³, b¹, c¹, gravitation may be applied. This would especially.
be the case when the commutator is used in connection with apparatus working
with alternating currents. Resistances may be inserted to equalize the circuits
through the commutator, as required. The box containing the commutator may
be arranged to form the foot of the lamp, or it may be placed separately in any
convenient place.
This commutator may also be applied to other electric lamps having carbons or
sets of carbons coming successively into operation.
And having thus described and ascertained the nature of this Invention, I declare
that I claim,
Firstly. A series of carbon rods resting on a larger cylinder, or piece of metal,
or each resting on a separate disc or piece of metal and automatically and succes-
sively brought into action, substantially as set forth.
Secondly. A series of carbon rods resting on a larger cylinder or piece of metal,
or each resting on a separate disc or piece of metal, the said cylinder or piece, or discs
or pieces, being mounted eccentrically and operating with an armature and electro-
inagnet in such a manner that they, when the current is interrupted at the place
of incandescence, turn on their axis, whereby the carbon point is raised and simul-
taneously made to push away any silicious deposit on the said cylinder or discs, as
set forth.
Thirdly. The series of weighted carbons a in tubes A in combination with
weighted levers g, cylinder or discs b, mounted eccentrically and operated by
armature and electro magnet, the parts being enclosed in a glass globe and arranged
suitable for mining purposes, all substantially as described with reference to Figures
1, 2, 3, and 4 of the accompanying Drawings.
Fourthly, A large negative carbon or other slab or piece in combination with one
or more carbon rods or slabs inclined against it, the voltaic arc gradually travelling
down the negative slab or piece, the whole being constructed and operating sub-
stantially as described with reference to Figure 5 of the accompanying Drawings.
Fifthly. Two carbon discs or plates with larger intervening space at the centre
than at the circumference and with or without non-conducting and non-combustible
substance or composition in the intervening space, the voltaic arc constantly
travelling around the circumference of the plates, substantially as described with
reference to Figures 6 and 7 of the accompanying Drawings.
..Sixthly. The commutator, substantially as described with reference to the accom-
panying Drawings, in which electro magnets in number one less than that of the .

page_text: number of carbons in connection therewith, are so arranged with armatures, contact
wires, and springs, or equivalent means, as to automatically throw one carbon into
action after the other as required.
In witness whereof, I, the said George Guillaume André, have hereunto set my
hand and seal, this Twenty-seventh day of August, in the year of our Lord
One thousand eight hundred and seventynine.
GEO. G. ANDRE. (L.S.)