Improvements in and connected with Electric Arc Lamps
Year: 1898

page_text: Improvements in and connected with Electric Arc Lamps,
I, FREDERICK RICHARD BOARDMAN, of 17, Leopold Street, Bow, in the County
of Middlesex, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to improvements in and connected with electric arc lamps
and is specially applicable to electric arc lamps for the theatrical stage, photo-
graphic work, search-light projectors and the like, where an electric are lamp
which can be used in any position is necessary. This end is attained and effected
by my invention and the lamp rendered automatic in its action as will be
hereafter described.
In carrying my invention into effect and in one form thereof I employ an
electric arc lamp in which the two carbon-holders are attached each to a toothed
rack, said racks being operated so as to bring the carbons near together or draw
them apart, as may be desired, by means of a pinion wheel which gears with said
racks. The said pinion wheel is attached to a spindle to which is also attached
one end of a clock spring which when wound up on the said spindle rotates the
pinion wheel and moves the racks thus separating the two carbon-holders. The
clock-spring will therefore in unwinding rotate the pinion wheel in the opposite
direction move the racks and thus bring the carbon-holders together. The other
endi of the clock-spring is fixed to any suitable fixed part of the apparatus. Gear-
ing with a toothed wheel attached to the clock-spring spindle, by means of a
ratchet wheel and pawl so that the clock-spring may be wound up without rotating
said toothed wheel, is a multiplying train of wheels of any suitable number.
The said multiplying train of wheels ends in a pinion to which is fixed an
ordinary clock-train fan to prevent the train of wheels racing and feeding the
carbons too rapidly. In the path of the said fan is placed a movable stop or
the like which is released when an iron core, which is operated by a shunt
solenoid, is sucked in by the current consequent upon the arc becoming lengthened
and the resistance of the arc becoming greater by the consumption of the
carbons.
In order to allow the arc lamp to be rotated in a vertical plane I pivot the
carbon-holders, racks and pinion, which are contained in a frame between two
supports, said pinion which gears with the racks being operated by a bevel
wheel on the spindle of said pinion. Said bevel wheel gears with another bevel-
wheel which is attached to a vertical spindle by means of a sleeve and key,
said spindle passing down through one of the two supports and is fixed to or
forms part of the clock-spring spindle. The whole of the clock-train and shunt
solenoid is thus placed at the base of the apparatus keeping the centre of gravity
low and at the same time allowing the arc lamp proper to be rotated in a vertical
plane. Fixed to the top of the support through which the spindle passes is a
device to throw the bevel wheels out of gear and allow the arc lamp to be
rotated in a vertical plane between its two supports. Said device may consist
of a pivotted lever held down by a spring which lever when lifted also lifts the

page_text: bevel wheel which is attached to the vertical spindle and is mounted upon the
movable sleeve, thus throwing the bevel wheels out of gear. To lock the arc
lamp in its position when the abovementioned pivotted lever is released I allow
the end of said lever to engage with a notched disc which is fixed to the frame
carrying the racks, pinion and carbon-holders and which thus locks the arc
lamp in its position. To allow the whole of the apparatus to be rotated in
a horizontal plane I mount the apparatus in a frame which terminates in a
vertical tubular foot or the like which fits into another vertical tube said tube
being fixed to a suitable base thus allowing the whole of the apparatus to be
rotated in a horizontal plane. I may of course use a set screw or other suitable
locking device to lock the apparatus in any suitable position.
In addition to using the fan and movable stop or the like in conjunction with
the iron core and shunt solenoid for feeding the carbons; for the purpose of
striking the are, that is separating the carbons, I use a cord or band one end
of which is attached to a barrel attached to the clock-spring and the other
end to a barrel (which may contain a spring) attached to the pinion wheel
which operates the racks, said. cord or band passing over suitable guide
pulleys. Near the said cord or band I have a brake pulley or other suitable
device carried on the end of a lever, said brake pulley or the like being pressed
against the cord or band and thus rotating the barrel attached to the pinion
and the spring in the barrel, takes up the slack in the cord or band, which operates
the racks and striking the arc when a series coil is energised and sucks in an
iron core attached to the other end of the lever carrying the brake pulley.
Another means of striking the arc is to have the key-way in the sleeve, to which
is attached the bevel wheel on the vertical spindle passing through one of the
two supports, slightly wider than the key itself so that the sleeve may be rotated
through a small angle and thus rotate the bevel wheels and pinion gearing with
the racks sufficient to strike the arc. To effect this I may place upon the said
sleeve a ratchet wheel which operates the sleeve in the abovementioned manner
when a pawl which may be operated by a series coil or solenoid or electromagnet
is brought to engage with it.
..
1000
FREDERICK RICHARD BOARDMAN, of No. 10, Union Court, Old Broad Street, in
the County of London, late of 17, Leopold Street, Burdett Road E., Electrical
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in
and by the following statement:-
My invention relates to improvements in and connected with electric arc lamps
and is specially applicable to electric arc lamps for the theatrical stage, photo-
graphic work, search-light projectors and the like, where an electric arc lamp
which can be used in any position is necessary. This end is attained and effected
by my invention and the lamp rendered automatic in its action as will be
hereafter described.
In carrying my invention into effect and in one form thereof I employ an
electric arc lamp in which the two carbon-holders are attached each to a toothed
rack, said racks being operated so as to bring the carbons near together or draw
them apart, as may be desired, by means of a pinion wheel which gears with said
racks. The said pinion wheel is attached to a spindle to which is also attached

page_text: one end of a clock spring which when wound up on the said spindle rotates the
pinion wheel and moves the racks thus separating the two carbon-holders. The
clock spring will therefore in unwinding rotate the pinion wheel in the opposite
direction move the racks and thus bring the carbon-holders together. The other
end of the clock-spring is fixed to any suitable fixed part of the apparatus. Gear-
ing with a toothed wheel attached to the clock-spring spindle, by means of a
ratchet wheel and pawl so that the clock-spring may be wound up without rotating
said toothed wheel, is a multiplying train of wheels of any suitable number.
The said multiplying train of wheels ends in a pinion to which is fixed an
ordinary clock-train fan to prevent the train of wheels racing and feeding the
carbons too rapidly. In the path of the said fan is placed a movable stop or
the like which is released when an iron core, which is operated by a shunt
solenoid, is sucked in by the current consequent upon the arc becoming lengthened
and the resistance of the are becoming greater by the consumption of the
carbons.
In order to allow the arc lamp to be rotated in a vertical plane I pivot the
carbon-bolders, racks and pinion, which are contained in a frame between two
supports said pinion which gears with the racks being operated by a bevel
wheel on the spindle of said pinion. Said bevel wheel gears with another bevel-
wheel which is attached to a vertical spindle by means of a sleeve and key,
said spindle passing down through one of the two supports and is fixed to or
forms part of the clock-spring spindle. The whole of the clock-train and shunt
solenoid is thus placed at the base of the apparatus keeping the centre of gravity
low and at the same time allowing the are Tamp proper to be rotated in a vertical
plane. Fixed to the top of the support through which the spindle passes is a
device to throw the bevel wheels out of gear and allow the arc lamp to be
rotated in a vertical plane between its two supports. Said device may consist"
of a pivotted lever held down by a spring which lever when lifted also lifts the
bevel wheel which is attached to the vertical spindle and is mounted upon the
movable sleeve, thus throwing the bevel wheels out of gear. To lock the arc
lamp in its position when the abovementioned pivotted lever is released I allow
the end of said lever to engage with a notched disc which is fixed to the frame
carrying the racks, pinion and carbon-holders and which thus locks the are
lamp in its position. To allow the whole of the apparatus to be rotated in
a horizontal plane I mount the apparatus in a frame which terminates in a
vertical tubular foot or the like which fits into another vertical tube said tube
being fixed to a suitable base thus allowing the whole of the apparatus to be
rotated in a horizontal plane. may of course use a set screw or other suitable
locking device to lock the apparatus in any suitable position.
In order to make the precise nature of my invention more readily understood,
I have appended hereto 2 sheets of drawings in which :-
Figs. 1 and 2 represent a form of arc lamp similar to that above mentioned,
but in which the shunt solenoid is placed horizontally behind the lamp and the
clock train at the side thereof.
Figs. 3.and 4 represent a similar form of lamp in which the shunt solenoid is
placed with its axis at right angles to the plane of the carbons.
Figs. 5 and 6 represent a form of lamp substantially as above described in
which the shunt solenoid and clock-train are placed at base of lamp proper.
In all cases siniilar letters of reference refer to similar or equivalent parts.
In all the above mentioned figures a represents the carbons and b carbon
holders, c are the racks and d is the pinion which operates same, d₁, represents
the spindle to which said pinion d is fixed, e is the clock-spring which operates
the pinion d, f indicates the case enclosing the clock-train and g is the fan which
said clock train terminates in h is the movable stop in path of said fan y and i is
the iron core which releases same when the iron core is sucked in by the shunt
solenoid k¹ is a spiral spring which tends to keep the iron core out and the

page_text: movable stop in contact with fan y when solenoid is not energised, 2 is a nut
or other means of adjusting the strength of said spring k, L and L represent
the two supports on which the frame m, arc lamp proper is pivotted to enable
it to rotate in a vertical plane, m', is the clamping device which in Figs. 5 and 6
consists of the before mentioned' notched disc fixed to frame of the lamp and in
Figs. 3 and 4 of an ordinary fly nut and screw, n is the tubular foot or the like
to enable the lamp to be rotated in a horizontal plane, and which in Figs. 3 and 4
.consists of an ordinary swivel attached to a hook n'. In order to wind the clock
spring up I provide a milled wheel o of any suitable material or ordinary key o
Figs. 5 and 6.
p is a reflector of any convenient shape and material the one shown being a
cast brass parabolic reflector and is fixed to the frame of the lamp in any suitable
nanner.
q is the device I prefer to use for clamping the carbons in position and consists
of an ordinary ring with a set screw which when tightened up clamps the ring
on to the carbon thus holding it rigidly.
r. r. are binding screws for clamping the positive and negative leads to the
respective carbon holders.
In Figs. 5 and 6 w, w¹, represents the bevel wheels which transmit the motion
from the clock-spring e to the pinion d, operating the racks c, y represents the
spring which normally holds the bevel wheels in gear and z is a spring catch
which locks came in position, w is the bevel wheel which slides on the spindle
and which is keyed to same by a sliding feather.
By way of a type or example I will describe the operation of one form of my
lamp when in actual use, and the said type being shown in Figures 1 and 2.
The clock spring, which feeds the carbons a together is first wound up by
the milled nut o thus separating the carbon holders. The carbons
may then
be adjusted to their full length. When the current is switched on there being no
circuit through the carbons the shunt solenoid & is energized and draws in the soft
iron core and stop h thus allowing the fan g and the clock train to rotate which
in so doing rotates the pinion d thus moving the racks and carbons together.
The circuit then being completed, through the carbons touching, the shunt
solenoid ceases to be energized and the spring asserting itself the motion of the
clock train is stopped.
When the carbons have burned away slightly the resistance of the are increases
the resistance of the circuit becoming greater the shunt solenoid kasserts itself
and feeds the carbon nearer together.
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 an electric arc lamp the use of two carbon holders operated by means
of two respective racks, said racks being operated by a pinion wheel substantially
as described.
2. In an electric arc lamp the use of two carbon holders operated by means
of two respective racks, said racks being operated by a pinion wheel which is
rotated by a clock spring substantially as and for the purpose described.
3. In an electric arc lamp the use of two carbon holders operated by means
of two respective racks, said racks being operated by a pinion which is rotated
by a clock spring said clock-spring being governed by a stop engaging with a
fan or the like connected through a train of wheels to the clock spring substantially
as and for the purpose described.
4. In an electric arc lamp the employment of a clock spring or the like said
clock spring being governed by a stop engaging with a fan or the like connected
through a train of wheels to the clock spring, said stop being operated by a soft
iron core or the like which is governed by a shunt solenoid substantially as
and for the purpose described.

page_text: 5. In an electric arc lamp the means for rotating the lamp in a vertical plane
substantially as described.
6. In an electric arc lamp the means for rotating the lamp in a horizontal
plane substantially as describest.
7. In an electric are lamp the combination of a lamp and feeding gear placed
at base of lamp substantially as and for the purpose described with reference to
Figs. 5 and 6.
8. In an electric arc lamp the combination of means of rotating the lamp
in the horizontal and vertical planes substantially as and for the purpose described.
9. In an electric arc lamp the combination of means of rotating the lamp in
the horizontal and vertical planes together with means for feeding the carbons
substantially as and for the purpose described.
Dated this 24th day of January 1899.
F. R. BOARDMAN,
10, Union Court, Old Broad Street, E.C.