Improvements in or relating to Incandescent Arc or Semi- incandescent Electric Lamps.
Year: 1890

page_text: Date of Application, 27th Feb., 1890
Complete Specification Left, 27th Nov., 1890-Accepted, 27th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in or relating to Incandescent Arc or Semi-
incandescent Electric Lamps.
I, FREDERICK RICHARD BOARDMAN, of No. 1, Brisbane Villas, Southend, in the
County of Essex, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to improvements in electric lamps of the semi-incandescent, or
arc-incandescent type; and it refers more particularly to improvements upon the
lamp known as the "Sun" lamp, for which Letters Patent No. 1704 of 1880 were
granted, and also to my former invention for which Letters Patent No. 110833 of 1887
were granted to me. By my present invention I am enabled to construct the lamp.in
a neater, cheaper, and lighter form, more convenient for trimming and in application,
and more efficient in use.
Heretofore, the block of marble or other refractory material used has been of a
square or rectangular section, with a conical light giving opening situated between
the seatings of the two carbon ends. Through and around the conical opening, and
the small channel between the carbon electros, the arc was caused to play upon the
block to render the same incandescent and luminous; the conical opening serving as
a reflector to transmit rays of light throughout an area bounded by the angle of the
opening. In my present invention I use a block, circular in section, with three
conical openings symmetrically placed around the circumference, each opening
radiating from the axis of the block. The lighted area is thus considerably increased.
The box, formally square in its central section, I now make of a circular form to
receive the cylindrical block, which enables me to simplify its construction and the
insulation of its parts, as well as to reduce its weight. Formally it was difficult to
renew the carbons and block-especially from a ladder-owing to the number of
parts to be unfastened or removed before a new block could be inserted. But by
means of a socketed portion and a bayonet joint, I am enabled to disconnect
and connect the two ends of my improved box, for trimming purposes, with great
facility.
The carbons are kept up to their respective seats in the block by spiral springs
within the tubular extensions of the box, with an exception described hereinafter for
lamps to be worked in parallel. The distance apart of the carbon electrodes,-and
therefore the length of the arc-is established by their seatings in the block as
heretofore with the exception noted above. But by making the block circular in
section, instead of square, and having three conical openings instead of one, the
sectional area kept in a state of incandescence is greatly reduced while the light
giving area of the block is increased; thus adding to the electrical efficiency of
the lamp.
The pencil carbon used for lighting the lamp is automatically advanced or withdrawn
through a tubular carbon and corresponding channel in the block, by the action of
one or more solenoids or electro magnets, having a suitable core, as described in my
Specification No. 10833 of 1887, aforesaid. The arrangement for controlling the
speed of withdrawal of the carbon in striking the arc, will vary, however, according
to the position of the automatic apparatus, and the character of the lamp.
In the case of a lamp to be worked in parallel and having the automatic gear above
the block, I employ three electro magnet coils, each furnished with a suitable.iron
core which is adapted to be drawn within the interior of the coil by the magnetising
force of the current passing therein. The first, called the lighting coil, is wound
to form a resistance approximately equal to that of the refractory block used, when
alight, and its core extends below and is fitted to form the piston of a dash pot. The

page_text: core is also prolonged upwards and engages with a toothed sector which takes into a
vertically moving rack. The rack is formed and adapted to hold the pencil carbon
and to advance or withdraw the same through the upper or tubular carbon electrode.
When the current is switched on to the lighting coil, the core of the latter is drawn
upward, carrying the pencil carbon downward (through the intervention of the toothed
sector and rack) until electrical contact is made between the carbons, when current
passes. At the same time the cut out coil becomes energised by current passing
through the same from the upper carbon holder, and it draws up its core which is
adapted to cut out the lighting coil. The weight of core of the latter draws the rack
and pencil carbon upward, and the speed of withdrawal is controlled by the action of
the dash pot.
3. Meanwhile the are has been struck, and the lamp lighted. Should the current
become excessive, the third, or regulating coil, is caused to raise the upper carbon
slightly, thereby lengthening the are, and increasing the resistance until the normal
quantity of current passes through the lamp. Conversely the upper carbon may be
lowered in a similar manner to shorten the arc, and lessen the resistance, when the
current is less than the amount required. In the latter case, however, the seating of
the upper carbon is deepened to allow of the requisite play but in most cases I prefer
to fix the minimum length of the arc.
1
The core of the regulating coil is caused to act upon a pivoted lever having an
adjustable counterpoise thereon. The lever is adapted to raise or lower (as the case
may be) the upper carbon holder, by engaging with a flanged projection on the latter.
By means of the adjustable counterpoise, the magnetic effect of the regulating coil
is caused to act upon the core according to the amount of current required for
the lamp.
In some cases I place the lighting coil below the block, and the regulating and cut
out coils above it. The tubular carbon electrodes are placed below, and the solid
carbon electrode vertically above the block, which is exactly reversed in the lamp
already described. The dash pot is likewise placed beneath, and the core of the
lighting coil is adapted to hold the pencil carbon. This is advanced within the block
until contact is made with the opposite electrode by the action of the coil upon the
core (as already described), and when the cut out coil performs its function, the
pencil carbon is withdrawn by the force of gravity, regulated by the dash pot.
Similar arrangements are used to those described, where the carbons are placed
horizontally, in which case the connections with the actuating magnet cores are
cranked.
In another form of lamp to be worked in parallel, the lighting coil is caused to
actuate a carbon electrode of the usual size (thus dispensing with the pencil and
tubular carbons), while the opposite electrode has about double its sectional area.
The latter is placed below the block and kept up to its seat in the block by a spiral
spring, arranged at the bottom of the tubular carbon holder. The remainder of the
apparatus. is placed above the block and it is to be noted that both the lighting
coil (which is series wound) and the shunt wound coil act to regulate the length
of arc.
The upper or movable carbon is secured by a vertically placed rack which gears
into a wheel or sector, in the same manner as the pencil carbon and its holder, first
described; and a series wound coil is adapted to control the gear wheel and rack also
through the intervention of a pointed lever on the axis of the gear wheel, with a pawl
on the lever engaging with ratchet teeth formed on the face of the gear wheel, or its
equivalent. A friction break is caused to bear upon a suitable face provided on or
attached to the gear wheel, and the break is made tight or loose by a weighted lever
working upon the main pivoted lever above named. The series wound coil, therefore,
acts upon the gear wheel and rack, and the movement of these latter is controlled by
the break which in turn is affected by the amount of current shunted through the
shunt wound coil. When an excess of current passes through the shunt coil, its core
is drawn down, entirely liberating the break and the upper carbon falls by gravity.
This reduces the resistance between the electrodes, and the current being then

page_text: increased in the series wound coil draws up the carbon to form a proper length of
arc. It follows therefore, that the balancing of magnetic action in the two coils
serves to regulate the length of arc, and the resistance of the lamp; in addition to
the function of striking the arc. It is to be understood that I may combine the
various parts or arrangements of the lamp to suit any special requirements.
Dated this 27th day of February 1890.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Incandescent Arc or Semi-
incandescent Electric Lamps.
1, FREDERICK RICHARD BOARDMAN, formerly of No. 1, Brisbane Villas, Southend,
in the County of Essex, but now of 3, Forest Villas, Manor Park, in the County of
Essex, Electrical Engineer, do hereby declare the nature of this invention, and in
what inanner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
My invention relates to improvements in electric lamps of the semi-incandescent or
arc-incandescent type, and it refers more particularly to improvements upon the lamp
known as the "Sun" lamp, for which Letters Patent No. 1704 of 1880 were granted;
and also upon my former invention for which Letters Patent No. 10833 of 1887 were
granted to me. By my present invention I am enabled to construct the lamp in a
neater, cheaper, and lighter form-more convenient for trimming and in application―
and more efficient in use.
In the accompanying drawing,
Fig. 1 is a vertical section through a hanging lamp, in which the carbons and
marble block are placed beneath the automatic lighting device and circuit connections,
and this lamp is intended for a series lamp, but will work in parallel with a suitable
resistance introduced.
Fig. 2 is a vertical section of a series lamp which will similarly work in parallel,
but the automatic lighting device and circuit connections are reversely placed to those
in Fig. 1, and the lamp is intended to be mounted upon a standard for street lighting
or the like.
Figs. 3, 4, and 5 are similar sections through lamps in which the automatic lighting
and regulating gear are placed upon a circular support of slate (or other suitable
material) above the carbons and block, as in Fig. 1, the slate also being adapted to
carry the globe which encloses the light giving parts.
Fig. 6 is a vertical section of a similar arrangement, but with a lower base or
support to carry the lower carbon and automatic lighting gear below the marble block.
All the above named figures are more or less in diagram, and other differences than
those above mentioned will be pointed out hereinafter.
Fig. 7 is a perspective view of the hanging lamp shown in Fig. 1 ;
Fig. 8 is a perspective view of the standard lamp shown in Fig. 2 with the addition
of an automatic cut out coil, but with the pulleys, cords and weight omitted;
Fig 9 is a perspective view of the break and feeding device shown in diagrammatic
elevation in Figs. 4 and 6;
Fig. 10 is a cross section through the improved circular three way block and its
containing box ; and
Fig. 11 shows an insulated connection between the said box and a carbon holder.
Similar reference letters refer to similar parts, or to parts having similar functions.
The improved block of marble or other suitable refractory material, a² is circular in
cross section, with a small central hole or channel for the pencil carbon b. The block
is cut away at three places on its circumference with solid connecting ribs of the
material intervening. These are spaced symmetrically as shown in the cross section
Fig. 10, (taken through the centre of the block a²) and when the block is incandescent,
light is radiated and reflected from the surfaces of these three openings, thus practically

page_text: giving an all-round light. The block a² is enclosed and held in a circular box a³
similarly cut away for the said openings to avoid obstructing the light, with similarly
formed projecting top and bottom flanges a', bolted to corresponding flanges secured
to the tubular holders a in which the carbon electrodes, a and a¹ are carried. The
flanges of the carbon holders as are insulated from and bolted to the flanges at of
the box a³, in the manner indicated by the section in Fig. 11. A pin on one of the
tubes as, (as shown in Figs. 7 and 8), engages with the bayonet joint a³, secured to the
base of the lamp, and by turning the box slightly, the whole of the light giving parts
and their receptacles, can be readily removed for trimming and as readily replaced.
Springs a', are placed within the tubes as to keep the carbon electrodes a and a² up to
their respective seats in the block a², and thus compensate for waste, except in the
case of lamps worked in parallel, to be described hereinafter. It is to be noted that
by making the block a² circular, instead of square as hitherto, and with three conical
openings instead of one, the amount of material kept incandescent is less, while the
light giving surface is increased, thus adding greatly to the electrical efficiency of
the lamp.
The pencil carbon b, used for lighting the lamp, (Figs. 1, and 3), is automatically
advanced or withdrawn through a tubular carbon a¹ and corresponding channel in the
block by means of one or more electro magnets (having a suitable core); as described
in my Specification to Letters Patent No. 10833 of 1887. The arrangement of
devices for controlling the speed in withdrawing the carbon-in lighting-varies
according to the position of the automatic devices, and the character of the lamp.
In the case of a lamp to be worked in parallel, and having the automatic gear above
the block, as in Fig. 5, I employ three electro magnets, each furnished with a suitable
iron core adapted to be drawn within the interior of the coil by the magnetising force
of the current passing therein. The first, called the lighting coil, 2, is wound to form
a resistance approximately equal to that of the refractory block a when incandescent,
and its core extends below and fitted to form the piston of the dash pot b³. The core
is also prolonged upwards and engages with a toothed sector b (which works on a
pivot) actuating a vertical rack 6, to which the pencil carbon is secured in any
convenient manner, and by which it is advanced or withdrawn through the tubular
carbon electrode a¹. When the current is switched on to the lighting coil 62, the core
of the latter is drawn upward and the pencil carbon b downward (through the inter
vention of the toothed sector and rack) until electrical contact is made between the
carbons, and the current passes. At the same time the cut out coil c has become
energised by current passing through the same from the upper carbon holder, and
draws up its core which is arranged by the cut out c¹ to cut the lighting coil 62 out of
the circuit. The weight of the core of the coil 62 draws the rack 65 and pencil
carbon b upward, and the speed of withdrawal is controlled by the action of the dash
pot 63 thus striking the arc, and lighting the lamp.
In the event of the current. becoming excessive, the third or regulating coil d is
brought into action through the circuit connections shown in Fig. 5, and its core is
caused to raise the upper or tubular carbon a¹ and its tubular holder d by the inter-
vention of the lever d² adjusted by the counter-weight d³. This lengthens the arc,
and increases the resistance until the normal quantity of current passes through the
lamp: Conversely, the upper carbon may be lowered to reduce the resistance when
the current falls below the amount required. In the latter case the seating of the
carbon a¹ in the block a² is deepened to permit the requisite travel, but in most cases
I prefer to fix the minimum length of arc by the depth of the seatings in the block a².
In some cases I place the lighting coil below the block, and the regulating and cut
out coils above it, as in Fig. 6. The tubular carbon electrode a' is placed below, and
the solid carbon electrode a vertically above the block a², exactly reversing the
arrangement for the lamp indicated by Fig. 5. The dash pot 63 is likewise placed
beneath the block a², and the core of the lighting coil b2 is adapted to hold and
actuate the pencil carbon b for lighting purposes, (as already described), the pencil
carbon being withdrawn by gravity and its speed regulated by the dash pot. Similar
means to those described' are used when the carbons are placed horizontally, the

page_text: intervening connections with the actuating magnet cores being cranked and pivoted.
This lamp is also adapted to be worked in parallel, the upper or solid carbon a being
deeply seated and adjustable in the block a² and secured to a rack holder 6 gearing
into the toothed wheel 6* actuated by the regulating coil d through the intervention of
the counter-weighted lever d², in the manner described with reference to Fig. 5. A
brake and feed device (described hereinafter) is also mounted on the axis of the
wheel 64.
In another form of lamp to be worked in parallel-indicated by Fig. 4-the lighting
coil 62 is caused to actuate a carbon electrode b, of the usual size (thus dispensing
with the pencil and tubular carbons shown in other figures), while the opposite
electrode a has about double its sectional area. The latter is placed below the block a²
and kept up to its seat therein by a spiral spring in the tubular holder a³. The
remainder of the apparatus is placed above the block a², and it is to be noted that
both the lighting coil b2 (which is series wound), and the regulating coil d (which is
shunt wound, act to regulate the length of arc, and therefore the resistance of
the lamp.
The upper or movable carbon b in Fig. 4, and a in Fig. 6, is secured in a rack
holder 6, placed vertically and adapted to gear into a toothed wheel or sector 64 as
indicated by the figures, and shown more particularly by the perspective view in Fig. 9.
A series wound coil b2 is adapted to control the gear wheel and rack through the
intervention of the pivoted lever d² on the axis of the gear wheel. A pawl d³ upon
the lever engages with fine ratchet teeth formed either on the face of the gear
wheel or sector 64, or its equivalent, a separate wheel d upon the same axis, and
turning therewith. A friction brake d is caused to bear upon a suitable face provided
on or attached to the gear wheel, or its equivalent, (shown in Fig. 9 as embracing
about one half of the fine toothed wheel ), and the break is made tight or loose by a
weighted levor d' working upon the main pivoted lever d² before mentioned. The
series wound coil, 62, therefore, acts upon the gear wheel 64 and rack 6, and the
movement of these latter parts is controlled by the break do, which on the other hand,
is affected by the amount of current shunted through the regulating coil d. When
an excess of current is shunted through the coil its core is drawn down, entirely
liberating the pawl and brake do and the upper carbon falls by gravity. This
reduces the resistance between the carbon electrodes, and the current being thereby
increased in the series wound coil 63, draws up the top carbon to form a proper length
It follows, therefore, that the balancing magnetic action in the two coils
serves to regulate the length of arc and resistance of the lamp in addition to the
function of striking the arc. When the lever d² falls too low as shown in Fig. 9, the
pawl d is lifted clear of d by a lifter coming in contact with a projection do upon
the frame. The working position of the lever and pawl is shown by the dotted lines.
of arc.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
:-
1. In incandescent arc lamps, the combination of the improved circular three way
refractory block with two carbon electrodes, substantially as and for the purpose
herein described.
2. In incandescent arc lamps, the combination of a circular three way refractory
block, a metallic case or box therefor, two carbon electrodes seated in the said block,
a tubular case for each electrode insulated from the aforesaid box, and means for
pressing the electrodes against the refractory block, substantially as and for the purpose
herein described.
3. In incandescent arc lamps, the combination of a circular three way refractory
block, a metallic case or box therefor, two carbon electrodes seated in the said block, a
tubular case for each electrode insulated from the aforesaid box, a pencil carbon
adapted to slide within one of the said carbon electrodes and automatic devices for
moving the same, and means for pressing the electrodes against the refractory block,
substantially as and for the purpose herein described.

page_text: 4. In incandescent arc lamps, the combination of a three way refractory block having
a carbon electrode seated therein, with a movable carbon electrode adapted to
automatically strike the arc or vary the resistance by the magnetic effect of two
electro magnets, through the intervention of a lever, feeding and break devices,
substantially as shown in Fig. 6 and for the purpose described.
5. In combination, a fine ratchet toothed wheel d' connected to or turning with a
toothed wheel 64, a rack carbon holder 65, a lever turning freely upon the axis of
the said wheels and actuated by the magnetic effect of one or more electro magnets, a
pawl d³ engaging with d*, a break do and counter-weight d' operating substantially as
and for the purpose herein described.
6. In incandescent arc lamps, the combination of an insulated box for containing a
refractory block, with carbon holders, and a bayonet joint attachment of the ports
adapted to be locked to, or unlocked from, the base or frame of the lamp, substantially
as and for the purpose shown and described.
7. In incandescent arc lamps, the improved arrangement of parts operating as and
for the purpose substantially as herein described and illustrated by Figs. 1, 3, 4, 5,
6, 7, and 8.
Davor this 20th day of November 1890.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.