Improvements in Alternating Current Arc Lamps
Year: 1898

page_text: Date of Application, 5th Sept., 1898-Accepted, 12th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in Alternating Current Arc Lamps,
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Build-
ings, in the County of London, Consulting Engineer and Chartered Patent
Agent, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by Hans Otto Swoboda, of New York, Sate of New
York, U.S.A.), and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement : —
This invention relates generally to an improved method of mounting fed
electro magnets which are subjected to the action of alternating currents in
electric arc lamp designed to be operated by alternating current.
As is well known, the rapid reversals of action in the alternating current,
used for operating such lamps, cause the feed magnets to vibrate so rapidly
that a humming or chattering noise is produced. If the magnet or magnets
are rigidly mounted on the supporting frame of the lamp, or on a base rigidly
attached to said frame, the vibrations of the magnets are transmitted to the
entire lamp and the sound is greatly magnified, so as to become highly objec-
tionable, especially when the lamp is used for indoor illumination. Moreover,
the vibrations thus transmitted to the lamp interfere with the steadiness of the
light and the smoothness of the feeding action.
According to the present invention this difficulty is overcome by mounting
the said feed magnet on a flexible base, and preferably interposing sound-
deadening material at the point of attachment to the supporting frame, and at
every point of possible contact between the magnet or its projections and said
supporting frame.
Obviously, any kind of a feeding device may be employed to cause the feeding
of the carbons under the control of the said magnet, but, preferably a clutch is
employed of the kind shown on the drawing, but which forms no part of the
present invention.
In as much as the movable core or armature of the solenoid magnet commonly
used becomes rigidly connected with said magnet under the action of the
magnetism when the current is passed through the solenoid, it also becomes
necessary to interpose a vibration-deadening connection between the said core
or armature, and the other portions of the feed mechanism of the lamp, and thus
the feed magnets and all parts which must necessarily experience the same vibra-
tions, are isolated completely from the other portions of the lamp so far as the
transmission of said vibrations is concerned.
The arrangement preferably employed for carrying out the said invention is
shewn on the accompanying sheets of drawings in which,-
Figure is a side elevation of a feed mechanism shewing a portion of the
supporting frame of the lamp and the improved method of mounting the magnets.
Figure 2 is a front elevation of the same.
Figure 3 is a vertical section corresponding to Figure 1.
Figure 4 is a vertical section corresponding to Figure 2, the section views
being designed to shew clearly the attachment of the core or armature of the
feed magnet to the feed mechanism.

page_text: Figure 5 is detail shewing a modified form of a spring plate attachment.
Figures 6 and 7 illustrate modified forms of armature connecting springs.
Throughout the drawings like reference figures refer to like parts.
1 represents the lower supporting plate of the lamp, 2 represents the upper
supporting plate. 3, 3, represent the feed magnet, which as shown, consists of
two solenoids, but which obviously might be of any form. 4, 4, etc., represent
the studs which form, the enclosing frame of the magnet. 5 is a flexible spring
plate, preferably having a curved portion 6, and a reversed portion 7, which
latter is attached to the plate. 2, by any convenient means, such as the screw
bolts, 8, 8, passing through the lug 9, on plate 2, and having the nuts 10, 10;
11 and 12 represent interposed layers of sound-deadening material, which
located between the flexible plate and the supporting plate 2, and nut 10.
Sleeves or thimbles 13, 13, of the same material may surround bolts, 8, 8,
where they pass through the part 7 of the spring plate.
are
Various kinds of material may be used for this purpose of deadening the
sound and other vibrations, such as asbestos, indurated fibre, paper, etc, or other
non-resonant material. In case the coils of the magnet and their connections
are not insulated completely from the spool or other support, the sound deadening
material should also be an electrically insulating material, but it is obvious that
nearly every form of such material such as mentioned above, is also an electrically
insulating material.
In order to prevent too extensive vibrations of the magnet, and to prevent
sagging of the same beyond a certain extent, stops 14 and 15, or other projec-
tions are extended to within a short distance of the plates 1 and 2, and in order
to deaden and prevent the creation of noise, and the transmission of vibrations
to the supporting frames, similar pieces of sound deadening material 16 and 17,
are located at all points of possible contact.
The magnets 3, 3, have the U shaped armature or double core 23, which is
supported by the spring 26, attached to its middle portion by the preferably
pivotal joint 29. The upper end of this spring 26, is attached to the depending
rod 28, mounted in the cross piece 21, to one end of which is connected the dash-
pot 22, while the other end is connected to the clutch 19, by the rods 30, 30,
or other equivalent device; the clutch is of known construction and therefore
does not require further description.
i
The mechanism above described is guided by the rod 27, fastened to the
plate 2 and having a telescoping joint with a prolongation of the part 28.
A modified form of supporting spring plate 5 is shewn in Figure 5. The bent
portion 6 of said spring plate being attached directly to the side of the lug 9,
by means of a screw 8, with the interposition of sound deadening material in
the same manner as described with reference to Figures 1 and 2.
Figures 6 and 7 illustrate modified forms of the spring 26, and it is evident
that still other forms of spring might be employed. The point to be kept in
view being only to provide a spring which will have sufficient flexibility to
prevent the transmission of vibrations, while at the same time it shall have
sufficient stiffness to render the clutch-operating mechanism responsive to move-
ments of the armature 23.
The other parts of the lamp shewn in the drawing, for clearness, are the
carbon carrier, 18, clutch supporting spring 20, lamp side rods, 24, 24, and
clutch tripping lugs 25, 25.
All parts of the lamp that are not hereinabove described, are of known con-
struction.
The mode of operation of the invention will be clear from the foregoing.
However rapidly the feed magnets may vibrate under the action of the alter-
nating currents, those vibrations will not be transmitted to the lamp, nor will
the sounds produced by such vibrations be magnified by communication to, and
amplification by, the metallic lamp structure, as is the case in ordinary lamps.
Evidently various changes could be made in the details of construction shewn,

page_text: without departing from the nature of the invention, so long as the essential
feature thereof, namely the interposition of a yielding medium at every point
of contact between the magnet and the lamp frame is retained.
The main object of this invention, as before stated, is to prevent the transmis-
sion of vibration from the feed magnets and their armature to the other portion
of the lamp and this is secured by interposing springs or soft non-resonant
material at every point of attachment and possible contact between said feed
magnet and armature and the other portions of the lamp. While every material
which will prevent transmission of such vibrations is included in this invention,
I shall refer to such materials by the expression "sound deadening material"
inasmuch as the most noticeable result of such vibrations is the series of sounds
which it is the object of this invention to eliminate from the operation of the
lamp.
Having now particularly described and ascertained the nature of this in-
vention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In an alternating current arc lamp, mounting the feed magnet or magnets
upon a flexible or sound deadening support in order to prevent the vibrations
thereof from being transmitted to the other parts of the lamp, substantially as
described.
2. In an electric arc lamp the combination of the supporting frame, the feed
magnet, a flexible or elastic support on which the said magnet is mounted and
sound deadening material interposed between the said support and frame at the
point of attachment thereof, substantially as described.
3. In an electric arc lamp the combination of the supporting frame having
an upper and lower plate, the feed magnet supported between the same by a
flexible, mounting, and sound deadening material interposed at all points of
possible contact between the said magnets and the said frame plates, substan-
tially as described.
4. In an electric are lamp supporting the feed magnet by means of a curved
spring plate such as 5, 6, 7, carrying the magnet and attached at its curved end
to the supporting frame, substantially as described.
5. In an electric arc lamp the combination of the supporting frame having
an upper and lower plate, the feed magnets supported between the same by a
flexible or elastic mounting and stops extending from said magnet to within
a short distance of one or more of the said plates, substantially as and for the
purpose described.
6. In an electric arc lamp with feed magnet mounted on a flexible or elastic
support, connecting the armature or core of the feed magnet to the clutch
mechanism by means of an elastic connecting device, substantially as described.
Dated this 5th day of September 1898.
ABEL & IMRAY,
Agents for the Applicant.