Improvements in Stage or like Arc Lamps for Alternating Currents.
Year: 1895

page_text: Date of Application, 3rd Sept., 1895
Complete Specification Left, 30th May, 1896-Accepted, 18th July, 1896
PROVISIONAL SPECIFICATION.
Improvements in Stage or like Arc Lamps for Alternating
Currents.
I, ALFRED SYKES of Turnbridge, Huddersfield, Yorkshire, Electrical Engineer
do hereby declare the nature of this invention to be as follows:-
This invention has reference more especially to electric arc lamps for alternating
current circuits, which are employed in place of lime lights for stage illumination,
and the primary object of my improvements therein is to avoid the objectionable
and to performers, rather distracting humming noise or sounds caused by the
alternating currents.
This I attain by arranging the arc to burn within an air tight chamber or
cylinder made of glass or partly of glass. The said chamber or cylinder fits
tightly at each end or top and bottom, into holders for supporting same, the joints
being made air tight by means of asbestos or other suitable packing which will
withstand the required temperature. Each holder is provided with an opening
or bush through which chased carbon holder rods are adapted to be fed into the
air tight cylinder by hand wheels or nuts, said bushes being made air tight by
adjusting nuts and washers or packing, or by a suitable form of gland. The carbon
holder rods may be arranged at any desired angle to the arc lamp box or frame.
The focussing of the light is performed by moving the lamp box, which contains
the lens, or lens and coloured glasses nearer to or further from the arc or glass
cylinder, a suitable handle with screw or locking device being employed for such
purpose. The lamp box or frame is also centred or pivotted to a suitably hinged
bracket, in or by which it can be moved to any angle or position desired to change
the direction of the light.
Instead of actuating the carbon holder rods by separate hand wheels, I may
employ spur gearing or worms and wheels actuated from the same shaft or spindle
so that both carbons may be fed simultaneously by one hand wheel.
Although I have described the arc light as being enclosed in an air tight
chamber or cylinder supported within the arc light box, I may dispense with the
chamber or cylinder and make the box itself air tight, a door being provided
for giving ingress to trim the carbons, and a clear glass introduced at the front
of the box for the light to pass through. In this case focussing is accomplished
by moving the lens, or lens and coloured glasses, away from the box.
By enclosing the are within an air tight chamber or cylinder, the noise or
sounds caused by the alternating currents is deadened; but if greater or absolute
quietness is desired, I employ a fixed or detachable air pump of any approved
make by which to pump out all air or gases in the cylinder and thus effectually
prevent the transmission of sound.
Dated this 31st day of August 1895
TASKER & CROSSLEY,
Huddersfield, Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Stage or like Arc Lamps for Alternating
Currents.
I, ALFRED SYKES, of Turnbridge Huddersfield, Yorkshire, 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:
This invention has reference more especially to electric arc lamps for alternating
current circuits which are employed in place of lime lights for stage illuminations
or projections, and the primary object of my improvements therein is to avoid the
objectionable and distracting humming noise or sounds caused by the alternating
currents.
This I attain by arranging the arc to burn within an air tight chamber or
cylinder made wholly or partly of glass or other transparent body.
The said chamber or cylinder fits tightly at each end or top and bottom into
holders for supporting same, the joints being air tight. Each holder is provided
with an opening or bush through which chased carbon holder rods are adapted to
be fed into the air tight cylinder by hand wheels or nuts.
The focussing of the light is performed by moving the lamp backward or forward
from or toward the lens or lens and coloured glasses. The lamp box or frame is
also centred or pivoted to a suitably hinged bracket, in or by which it can be
moved to any angle or position desired to change the direction of the light.
Instead of actuating the carbon holder rods by separate hand wheels, I may
employ spur gearing or worms and wheels actuated from the same shaft or spindle
so that both carbons may be fed simultaneously by one hand wheel.
In order that my said invention may be fully understood reference is herein
had to the annexed sheet of drawings forming a part of this specification in
which :-
Fig. 1 is a vertical section, taken on line 1-2 of Fig. 2, of an arc lamp for
stage or platform projections embodying my invention ;
Fig. 2 is plan of same, and
Fig. 3 rear elevation, looking in the direction of arrow 3.
Fig. 4 is a detail afterwards referred to.
In the drawings A represents the arc lamp box, which may be the ordinary
lime box minus the lime light fittings, and B the arc lamp supported therein by a
stand or pedestal C, the arm or extension C¹ of which is secured by thumb screw D
to the plate E attached to or formed on the bottom of the box, the lateral edges
of said arm being bevilled or wedge shaped and fitting into a corresponding groove
or way in the plate E in which it can be moved forward or backward by handle C
to move the lamp nearer to or further from the lens or lens and coloured glasses
at the front of the box to obtain the proper focus, a longitudinal slot C³ being
formed in the arm C¹ to allow for the full extent of adjustment in either direction.
The lamp consists of a cylinder a composed of glass or other suitable trans-
parent body, or partly of glass and partly of metal the glass occupying a position
at the front of the lamp as indicated at b.
Each end of said cylinder is turned or ground to a true face in order to fit
tightly into the caps or holders c, d which are likewise provided with corresponding
internal true faces to receive same so that the joints made between the parts shall
be air tight. If required, or preferred asbestos or like packing which will with-
stand the temperature, may be used to further seal the joints.
The upper cap or holder e is made separate and detachable and is screwed onto
the central portion d' of the upper end of the lamp which is of one piece with
the bottom holder d being connected thereto by tubular columns or pillars d', ď³,

page_text: the latter of which may be solid as it serves no purpose beyond giving uniformity
of appearance and adding to the strength or rigidity of the lamp.
The parts d, d, are provided with openings or bushes through which the upper
and lower carbon holders e and fare adapted to be fed into the air tight chamber
or cylinder, and suitably secured to said parts or part d¹ and frame C so as to
rotate freely thereon are toothed wheels e, f, gearing respectively with toothed
wheels 9. h, fast on the spindles or shafts g', ', which carry hand wheels g², h², for
rotating satne.
The carbon holders have external screw threads formed thereon which are
adapted to take into corresponding internal screw threads formed in the toothed
wheels e, f, which being capable of rotation only, act as nuts therefor and when
rotated from the shafts g', ', cause said bolders to work through same in either
direction and separate or bring the carbons i, i, together.
I prefer to actuate each carbon holder separately as shewn and described, but
it will be obvious that they may be actuated simultaneously from one hand wheel
by mounting both driving wheels on one and the same shaft.
The lower cylinder holder d is insulated from the stand C by an insulator j
and the screws K by which it is secured to said stand, which are also insulated
from the lamp.
The two terminals are shewn at and m one being secured to the stand or
pedestal C and the other to the part d' or upper end of the lamp. When access
to the interior of the lamp is desired to trim the carbons or for other purposes,
the cap or upper holder c is unscrewed off the part d' thus releasing the cylinder a
and enabling it to be removed from the lamp without loss of time and with a
minimum amount of trouble. The lamp instead of being vertical as shewn may
be arranged at any angle to suit requirements; the lamp box being pivoted or
centred in the ordinary manner for projecting the light in any direction.
The arc lamp may be made angular in the form of a box and the lime box
dispensed with, the lens or lens and coloured glasses being supported in an adjustable
frame or stand movable to or from the lamp to obtain the focus, and the lamp
pivoted or centred in a similar manner to an ordinary lime box to vary the angle
or direction of projection.
In conjunction with an air tight are lamp for alternating current circuits for
stage projections I may use an electro magnet n situated at the rear of the air
tight chamber for projecting the arc to the front of the carbons, as illustrated in
Fig. 4, and I may in addition make the end of the pole piece n¹ of said electro
magnet in the form of or provide it with a concave reflector, as indicated in dotted
Jine in same figure.
By enclosing the arc within an air tight chamber or cylinder the humming noise
or sound caused by the alternating currents employed in arc lamps for stage
projections, is deadened, but if greater or more absolute quietness is desired,
1 pump or exhaust all air or gases out of the cylinder, and thus effectually prevent
the transmission of sound.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be carried into effect, 1 declare that
what I claim is :-
Firstly. For stage or like projections, an arc lamp for alternating current
circuits constructed with an air tight chamber within which the arc is struck and
burns, combined with a lime box such as A substantially as herein shewn and
described and for purposes set forth.
Secondly. For stage and like projections, the general arrangement, construction
and combination of parts comprising an arc lamp for alternating current circuits
provided with air tight chamber, enclosing the carbons and means for feeding the
carbon holders into said air tight chamber and bringing the carbons together
or separating them, in mauuer and for purposes substantially as herein shewn and
described.

page_text: Thirdly. For stage and like projections, the combination with an air tight arc
lamp for alternating current circuits and enclosing lime or equivalent box of an
electro magnet situated in the air tight chamber and at the rear of the carbons and
having a pole piece with or without reflector on the end thereof for repelling
or projecting the arc to the front of the carbons substantially as herein set 5
.forth.
Dated this 20th dow of Mor 1906