Year: 1895

page_text: JOSEPH DEVONPORT FINNEY ANDREWS 45 Fulham Park Gardens London
S:W. do hereby declare the nature of this invention to be as follows:-
My invention relates to the regulation and maintenance of the electric arc at the
most suitable length for lighting purposes with constant electric pressure but under
considerable changes in the strength of the current and to increasing the length of
burning of are lamps without renewal of carb ons. I control the length of the arc
by an electromagnet having an armature in the form of a wheel or pulley, free to
revolve. Over this wheel armature is a band carrying a carbon holder at each
end, the upper one of which would be the heavier and in consequence would rotate
the wheel when no current is passing and thus bring the carbons into contact with
one another.
When current passes through the magnet coil the wheel with its band
would be attracted to one of the poles of the magnet and would then be rotated
in such a direction by the attraction of the other magnet pole or by a projection
or special form of the same pole that au arc would be started, and the length of
this arc would be maintained by the wheel slipping round as the magnet weakens,
under the influence of the preponderating weight. Instead of a weight to move
the wheel a spring may be employed. The band over the wheel armature is
prevented from slipping on it in consequence of being gripped between the
periphery of the wheel and the magnet pole. Instead of the attraction of the
magnet being made to take place at the periphery it may be at a coned centre or
at the side of the wheel, the strike of the arc in these cases being arranged by an
oscillation of the magnet towards another armature. I sometimes arrange the
armature of the magnet to act on two wheels arranged in bearings in such a way
that an extension of the armature will press between them and in doing so rotate
them in one position and he free from them or nearly so in another, depending
upon the strength of current in the controlling magnet coil. The wheels may be
of iron as in the former cases and the armature extension of iron so as to have
attraction between them when current passes thro' the magnet coils. If it
should be desirable to make the attraction of the wheels greater I may magnetise
them by separate coils. Or I may employ only friction between the armature
extension and the wheels to effect their movement in which case I would construct
the extension in any suitable form or material. The carbon holders would be.
carried at the ends of a band passing over one of the wheels as in the former cases
or it may be by a separate wheel on the same axis.
Both wheels or axles actuated by the armature extension may carry bands with
carbon holders in which case the lamp would be of the double carbon type. The
method of carrying the carbons which I prefer to employ consists of a frame on a bent
arm fixed to one end of the band by its upper end and carrying a suitable carbon
holder at the lower end this forming the lower carbon holder. The upper carbon
would be held in a holder attached to a weight connected to the band. The
carbons thus held would be in' direct line with one another, and guided so as to
retain this position by suitable guides near the burning ends.. The guides may be
substituted by a globe with holes fitting the carbons. This globe would have little.
or no circulation of air and would in consequence increase the burning life of the
carbona

page_text: To lessen the deposit on the glass due to the burning of the carbons I
construct the globe with an inner shield preferably cylindrical in form placed
round the arc. I may make the globe in two or more parts and I sometimes make
it open at the bottom. I may carry the globe by an arm attached to the lamp or
I may carry it on an abutment pole preferably resting on the bottom carbon.
When I desire to make the lamp work with more than one current strength
1 arrange a separate armature so as to cut in or out more or less turns of the
electro magnet or solenoid according to the current the lamp is to work at. This
armature may be operated by the main magnet of the lamp or by an additional
one. The armature may be a cone to a solenoid. Instead of cutting out coils of
the magnet I may make part of the coil moveable by the, action. of an electro
magnet so as to put the part out of action or reduce its influence or I may move
by the same means the whole coil to a point of lesser influence when the current
increases. This applies to a solenoid or any form of electro magnet.
Dated this 23rd day of August 1895.
J. D. F. ANDREWS.
improvements in Aro Lamps.
JOSEPH DEVONPORT FINNEY ANDREWS Electrical Engineer 45 Fulham Park
Gardens, London, S.W. 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:-
I
My invention relates to the regulation and maintenance of the electric are at the
most suitable length for lighting purposes with constant electric pressure but under
considerable changes in the strength of the current and to increasing the length of
burning of the arc lamp without renewal of carbons. I control the length of the
arc by an electro magnet A (Fig. 1) with an armature B in the form of a wheel
free to revolve in bearings C carried by a rocking frame D which is pivoted by
one end at E and attached to an adjusting spring F. by the other at G. Over this
wheel armature is a band H attached to the upper carbon holder I by one end and
to the lower carbon holder rod K by the other end. The upper carbon holder is
the heavier and tends to cause the carbons to meet which they would do when no
current is passing. I preferably construct the electro magnet A in horseshoe form
with one of the legs R longer. than the other M.
On the face of the long magnet leg and below the short one is arranged the wheel
armature and band and when the current passes through the coil N of the magnet the
wheel would be attracted against the face of the long leg and thereby grip the band
between them. Simultaneously the short magnet leg would attract the wheel
upwards and strike the arc, the length of which would be maintained by the wheel
armature slipping round under the influence of the preponderating weight of the
upper carbon holder as the magnet weakens in consequence of the growing length
of the arc.
For the purpose of providing a finer adjustment of the length of the arc I carry
the rocking frame by a spring F to which greater or less tension is given by an
adjusting screw. To facilitate the slipping round of the wheel I find it advan-
tageous to fit a piece of non-magnetic material O. below the face of the long
magnet leg so that when the wheel armature is in its lowest position it rests ou the
brass piece and is not under such strong attraction. I may employ the magnetic
grip described and shown for the band to act on any other form of carbon holder
such as one with a rod instead of a band on the carbon direct without a holder.
The method of carrying the carbons which I prefer to employ consists of a frame
or a bent arm K attached by its upper end to the band passing over the wheel

page_text: armature and by its lower end to a suitable carbon holder P. At the upper end
of this frame I provide a guide consisting of a cross arm Qresting and sliding
against two vertical rods L forming the frame of the lamp. I prefer to insulate
this cross arm from the carbon holder frame and I also prefer to pivot the frame
to the cross arm at S to provide freedom sideways.
The upper carbon holder would be weighted and attached by a neck T to a similar
cross arm guide U to that of the lower carbon holder. The carbons held by the
above described holders would be guided in direct line with one another by suitable
guides near the burning ends of the carbons. These guides may be formed by a
globe with holes top and bottom to fit the carbons. When I wish to prolong the
life of the carbons I construct the globe above referred to of small dimensions and
fit the openings with metal guide collars and a loose heavy ring ▼ the hole in
which closely fits the carbon. This ring resting on the guide collar increases the
air tightness of the entrance for the carbons. The ring W for the lower carbon is
arranged on the inside of the globe. When I wish to lessen the deposition of the
carbon dust on the globe I provide an inner shield preferably tubular or
cylindrical in shape round the arc. I sometimes make the globe open at the
bottom.
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 1
claim is :-
1. The wheel armature and grip applied in conjunction with an electro-magnet
for the purpose of holding and adjusting the carbons in an arc lamp to the correct
relation with one another to maintain the electric arc at the correct length
substantially as described and shown generally in the illustration.
2. The method of suspending the carbons by arms on the ends of a band and
guiding them by guides placed near the burning ends of the carbons either by the
globe or independent guides substantially as described and shown in the
illustration.
3. Increasing the air tightness of the globe surrounding the arc by heavy
washers or rings as described and shown in the illustration.
Dated this Twenty-second day of May One thousand eight hundred and
ninety-six.
J. D. F. ANDREWS.