Year: 1898

page_text: Date of Application, 1st Mar., 1898
I, REGINALD BELFIELD, 32, Victoria Street, in the City of Westminster,
Electrician, do hereby declare the nature of this invention to be as follows:-
My invention relates to arc lamps and more particularly to such lamps as are
adapted to be operated by alternating currents.
The object of my invention is to provide a lamp which will strike the are and
burn without material pumping or sputtering, and which will burn steadily
without material variation in the amount of current consumed and with a
minimum of noise.
An important feature of my invention consists in an improved design of
core for the regulating magnet, the magnetic portion of said core being con-
nected through a spring to the brake lever, and having interposed between
its upper end and said lever, a washer of felt or other yielding material. By
this means the action of the solenoid upon the brake is delayed owing to the
lost motion between the core and the brake lever, also the resilient cushion
obviates the jarring which would occur on the coming together of the metal
parts, and also prevents the noise due to the action of an alternating current
upon metal parts not rigidly joined together and located in the magnetic field
produced by said current.
Another feature of my invention consists in an improved dash-pot, one of
the members of which has a graphite bearing surface, said dash-pot is also
supported on a resilient cushion to prevent jarring and noise. My invention
further comprises an improved device for supporting the lower carbon which
is connected to its rod by a loose joint, the upper end of said carbon passing
through a guiding and supporting ring which ensures the proper location of
its point with reference to the lower end of the upper carbon.
In the accompanying drawings I have shewn an arc lamp constructed accord-
ing to my invention.
Figure 1 being a vertical section of the globe and casing the operating parts
being shewn mainly in elevation. Figure 2 is a vertical section through the
feed controlling solenoid and its core.
Figure 3 is an elevation, at right angles to Figure 1, of the carbon feeding
mechanism. Figure 4 is a side elevation of a portion of the carbon feeding
mechanism the dash-pot cylinder being shewn partially in section. Figures 5
and 6 are respectively a plan and a sectional view of the clamp for the lower
carbon, and Figure 7 is a plan view of the solenoid core, the cap being removed.
1 is a globe which is supported from the frame by a netting 1ª, and spring
connectors 2, being provided at the bottom with a removable cup 3. The feed-

page_text: ing mechanism is separated from the globe by a considerable air space and is
supported upon a base 4 connected to the plate 5 at the top of the globe by
means of rods 6. The under side of the plate is burnished or enamelled so as to
serve as a reflector. By this arrangement the operating mechanism of the lamp
is protected from the heat of the arc. The space between the plates 4 and 5
may be left open or may be partially or wholly closed, the free circulation of air
in the space being desirable. The lower carbon 7 is mounted in a holder 7ª,
which is loosely mounted upon the horizontal arm of a rod 8, as shewn in
Figure 6. The vertical portion of the rod 8 extends through an opening in
the plate 5 its upper end being secured to a guide plate 10 which is guided
by three of the rods 6, only two of which are however shewn in the drawing.
The plate 5 may be provided with a guiding sleeve 5ª for said rod, to the lower
part of which sleeve is secured a guide 9 surrounding the upper part of the
carbon thereby ensuring the proper location of the latter with reference to
the lower end of the upper carbon. The loose connection between the carbon
holder 7 and the rod 8 prevents any binding action between the said carbon
and its guide, a proper electrical connection being provided between the two
parts by the wire 7b. The upper carbon 11" is secured in a holder 11 to which
is attached a weight 12 guided by three of the rods 6 and said weight is con-
nected through a suitable flexible connection preferably a sprocket chain 13
to the plate 10 at the top of the lower carbon rod 8. The chain 13 passes over
and is supported by a sprocket wheel 14, mounted on a shaft 15, which is jour-
nalled in a frame 16 secured to the base 4. The gear wheel 17 is also rigidly
mounted upon the shaft 15 and meshes with a pinion 18 to which is secured a
sleeve 19, loosely surrounding the shaft 19". Secured to the sleeve 19 is a
brake wheel 20 and rigidly mounted upon the shaft 19" is a lever 21; to one
end of said lever is pivotally secured a dash-pot cylinder 22 provided with
adjusting weights 22", and to the other end is secured a solenoid core 23. To
the lever 21 at or near the end supporting the core 23 is secured a brake strap 24
which passes round the brake wheel 20 and is secured to a pin 25 on the short
arm of a releasing lever 26 pivotted to the lever 21. The pin 25 extends through
a curved slot 27 in the lever 21, which slot limits the movement of the lever 26
on its pivot. The long arm of the lever 26 is adapted to impinge upon a stop
which in the lamp shewn is the shaft 15, and a spring 28 is provided which nor-
mally presses the lever against the stop. The construction of this brake appara-
tus is clearly shewn in Figure 4 which also exhibits my improved dash-pot,
in which in order to secure a sufficiently close contact between the cylinder
and plunger, and at the same time obtain a free relative movement of the two
parts, the bearing surfaces are made of graphite. In the present instance the
plunger head 29 is entirely of this material, but obviously its peripheral surface
or the inner surface of the cylinder only, might be made of this material. The
lower end of the plunger rod 29" is provided with a metal disc 29b clamped
between two felt discs 29°. By this means slight lateral movements of the
plunger are permitted, and at the same time any rattling of the parts prevented.
The operating solenoid 30 is supported in a metal frame 32 from which it is
separated at the top by insulating material 31, and the frame 32 is adjustably
secured by means of the slots 32" to the frame 16 of the lamp. Between the
bottom of the solenoid 30 and the frame 32, are insulating rings 31" and inter-
posed annular iron plates or washers 31b the latter being employed to ensure
a more nearly uniform pull upon the core 23 throughout its range of movement.
The parts just described rest upon a yielding resilient cushion 33 preferably of
felt, which serves as a buffer against which the lower end of the solenoid core
may impinge, and also largely decreases the noise incident to the use of an
alternating current for arc lamps by reason of its deadening effect, and its
cushioning action with reference to the solenoid, and its supporting frame.
The solenoid core 23 consists of a strip of iron rolled into a tube. This is secured
to a plate 34 at one end and connected through a spring 36 to a plate 35 pivotally

page_text: attached to the end of the lever 21. A yielding resilient cushion 37 is interposed
between the plate 35 and the tube 23. This cushion is preferably of felt, and
serves to obviate the noise which would otherwise occur upon the coming together
of the parts 23 and 35 and also tends to prevent the jarring due to the action of
an alternating current upon metal parts not rigidly joined together, when in
a magnetic field produced by the current.
The circuit through the lamp is as follows;-
By conductor 41 solenoid 30 conductor 41" to the top carbon holder 11, the
carbons the bottom carbon holder 7ª rod 8 conductor 42 and conductor 42";
the adjustment of the parts is such that the arc is always located just below the
plate 5.
The operation of the lamp is as follows:-
The weights of the several parts are such that when no current is flowing the
dash-pot cylinder 22 is in its lowest, and the solenoid core 23 in its highest
position. The end of the releasing lever 26 is resting on its stop, being pressed
against the same by the spring 28, the brake band 24 will therefore be slack
and the brake wheel 20 free to revolve, hence owing to the weight 12 the upper
carbon 11" will drop and the lower carbon 7 be raised until the two are in contact.
As soon as the current is turned on, the solenoid 30 draws its core quickly down-
ward, but owing to the lost motion between the main tube of the core and the
lever 21, the lever will be rotated without jerk. The rotation of the lever 21
raises the releasing lever 26 from its stop and tightens the band 24 upon the
brake wheel 20, and the latter with its pinion 18 will be moved rotating the
gear wheel 17 and the brake wheel sufficiently to separate the carbons and
strike the arc. Owing however, to the construction of the solenoid core above
described, there will be very little likelihood of the lever 21 moving so quickly
as to over-strike the arc and cause the pumping action which is apt to take place
in alternating current arc lamps. As the carbons are consumed the resistance
of the arc increases, and the current through the solenoid 30 diminishes per-
mitting the core 23 which is over-balanced by the weight of the dash-pot
cylinder 22 to rise, and the lever 21 tilts sufficiently to bring the brake releasing
lever 26 in contact with its stop. The brake wheel 20 will therefore be released
and the weighted upper carbon rotates the wheel 14, bringing the carbons nearer
together, and restoring the arc to its proper length; when this is done the cur-
rent becoming normal, the solenoid 30 attracts its core and restores all the parts
of the gearing to their normal position.
With the mechanism described, the feeding of the carbons is so gradual and
is so accurately in accord with the requirements, that there is almost no variation
in the amount of current taken by the lamp.
While we have described specific details in carrying out our invention, we
desire it to be understood that changes may be made therein without departing
from the spirit and scope of the invention, and consequently we do not desire
to be limited to the details of construction shown and described.
D
1 L
11. of Manch 1908

page_text: the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
My invention relates to arc lamps and more particularly to such lamps as are
adapted to be operated by alternating currents."
The object of my invention is to provide a lamp which will strike the arc and
burn without material pumping or sputtering, and which will burn steadily
without material variation in the aniount of current consumed and with a
minimum of noise.
An important feature of my invention consists in an improved design of
core for the regulating magnet, the magnetic portions of said core being con-
nected through a spring to the brake lever, and having interposed between
its upper end and said lever, a washer of felt or other yielding material. By
this means the action of the solenoid upon the brake is delayed owing to the
lost motion between the core and the brake lever, also the resilient cushion
obviates the jarring which would occur on the coming together of the metal
parts, and prevents the noise due to the action of an alternating current
upon metal parts not rigidly joined together and located in the magnetic field
produced by said current.
Another feature of my invention consists in an improved dash-pot, one of
the members of which has a graphite bearing surface, said dash-pot is also
supported on a resilient cushion to prevent jarring and noise.
Referring now to the accompanying drawings 1 have therein shewn an arc
lamp constructed according to my invention.
Figure 1 is a vertical section of the globe and casing the operating parts
being shewn mainly in elevation. Figure 2 is a vertical section through the
feed controlling solenoid and its core.
Figure 3 is an elevation, at right angles to Figure 1, of the carbon feeding
mechanism. Figure 4 is a side elevation of a portion of the carbon feeding
mechanism the dash-pot cylinder being shewn partially in section. Figures 5
and 6 are respectively a plan and a sectional view of the clamp for the lower
carbon, and Figure 7 is a plan view of the solenoid core, the cap being removed.
I is a globe which is supported from the frame by a netting 1ª, and spring
connectors 2, being provided at the bottom with a removable cup 3. The feed-
ing mechanism is separated from the globe by a considerable air space and is
supported upon a base 4 connected to the plate 5 at the top of the globe by
means of rods 6. The, under side of the plate is burnished or enamelled so as to
serve as a reflector. By this arrangement the operating mechanism of the lamp
is protected from the heat of the arc. The space between the plates 4 and 5
may be left open or may be partially or wholly closed, the free circulation of air
in the space being desirable. The lower carbon 7 is mounted in a holder 7",
which is loosely mounted upon the horizontal arm of a rod 8, as shewn in
Figure 6. The vertical portion of the rod 8 extends through an opening in
the plate 5 its upper end being secured to a guide plate 10 which is guided
by three of the rods 6, only two of which are however shewn in the drawing.
The plate 5 may be provided with a guiding sleeve 5" for said rod, to the lower
part of which sleeve is secured a guide 9 surrounding the upper part of the
carbon thereby ensuring the proper location of the latter with reference to
the lower end of the upper carbon. The loose connection between the carbon
holder and the rod 8 prevents any binding action between the said carbon
and its guide, a proper electrical connection being provided between the two
parts by the wire 7. The upper carbon 11ª is secured in a holder 11 to which
is attached a weight 12 guided by three of the rods 6 and said weight is con-
nected through a suitable flexible connection preferably a sprocket chain 13
to the plate 10 at the top of the lower carbon rod 8. The chain 13 passes over
and is supported by a wheel 14, mounted on a shaft 15, which is jour-
nalled in a frame 16 secured to the base 4. The gear wheel 17 is also rigidly
mounted upon the shaft 15 and meshes with a pinion 18 to which is secured a

page_text: sleeve 19, loosely surrounding the shaft 19ª. Secured to the sleeve 19 is a
brake wheel 20 and rigidly mounted upon the shaft 19ª is a lever 21; to one
end of said lever is pivotally secured a dash-pot cylinder 22 provided with
adjusting weights 22", and to the other end is secured a solenoid core 23. To
the lever 21 at or near the end supporting the core 23 is secured a brake strap 24
which passes round the brake wheel 20 and is secured to a pin 25 on the short
arm of a releasing lever 26 pivotted to the lever 21. The pin 25 extends through
a curved slot 27 in the lever 21, which slot limits the movement of the lever 26
on its pivot. The long arm of the lever 26 is adapted to impinge upon a stop
which in the lamp shewn is the shaft 15,, and a spring 28 is provided which nor-
mally presses the lever against the stop. The construction of this brake appara-
tus is clearly shown in Figure 4 which also exhibits my improved dash-pot,
in which in order to secure a sufficiently close contact between the cylinder
and plunger, and at the same time obtain a free relative movement of the two parts,
one or both of the bearing surfaces are made of graphite. In the present instance the
plunger head 29 is entirely of this material; but obviously its peripheral surface
or the inner surface of the cylinder only, might be made of this material. The
lower end of the plunger rod 29" is provided with a metal disc 29b clamped
between two felt discs 29°. By this means slight lateral movements of the
plunger are permitted, and at the same time any rattling of the parts prevented.
The operating solenoid 30 is supported in a metal frame 32 from which it is
separated at the top by insulating material 31, and the frame 32 is adjustably
secured by means of the slots 32 to the frame 16 of the lamp. Between the
bottom of the solenoid 30 and the frame 32, are insulating rings 31 and inter-
posed annular iron plates or washers 31b the latter being employed to ensure
a more nearly uniform pull upon the core 23 throughout its range of movement.
The parts just described rest upon a yielding resilient cushion 33 preferably of
felt, which serves as a buffer against which the lower end of the solenoid core
may impinge, and also largely decreases the noise incident to the use of an
alternating current for arc lamps by reason of its deadening effect, and its
cushioning action with reference to the solenoid, and its supporting frame.
The solenoid core 23 consists of a strip of iron rolled into a tube. This is secured
to a plate 34 at one end and connected through a spring 36 to a plate 35 pivotally
attached to the end of the lever 21. The plate 34 is preferably radially slit or
slotted to prevent secondary currents. A. yielding resilient cushion 37 is internosed
between the plate 35 and the tube 23. This cushion is preferably of felt, and
serves to obviate the noise which would otherwise occur upon the coming together
of the parts 23 and 33 and also tends to prevent the jarring due to the action of
an alternating current upon metal parts not rigidly joined together, when in
a magnetic field produced by the current.
The circuit through the lamp is as follows:-
By conductor 41 solenoid 30 conductor 41" to the top carbon holder 11, the
carbons, the bottom carbon holder 7, rod 8, conductor 42 and conductor 42":
the adjustment of the parts is such that the arc is always located just below the
plate 5.
The operation of the lamp is as follows:-
The weights of the several parts are such that when no current is flowing the
dash-pot cylinder 22 is in its lowest, and the solenoid core 23 in its highest
position. The end of the releasing lever 26 is resting on its stop, being pressed
against the same by the spring 28, the brake band 24 will therefore he slack
and the brake wheel 20 free to revolve, hence owing to the weight 12 the upper
carbon 11 will drop and the lower carbon 7 be raised until the two are in contact,
As soon as the current is turned on, the solenoid 30 draws its core quickly down-
ward, but owing to the lost motion between the main tube of the core and the
lever 21, the lever will be rotated without jerk. The rotation of the lever 21
raises the releasing lever 26 from its stop and tightens the band 24 upon the
brake wheel 20, and the latter with its pinion 18 will be moved rotating the

page_text: gear wheel 17 and the brake wheel sufficiently to separate the carbons and
strike the arc. Owing however, to the construction of the solenoid core above
described, there will be very little likelihood of the lever 21 moving so quickly
as to overstrike the arc and cause the pumping action which is apt to take place
in alternating current arc lamps. As the carbons are consumed the resistance
of the arc increases, and the current through the solenoid 30 diminishes per-
mitting the core 23 which is over-balanced by the weight of the dash-pot
cylinder 22 to rise, and the lever 21 tilts sufficiently to bring the brake releasing
lever 26 in contact with its stop. The brake wheel 20 will therefore be released
and the weighted upper carbon rotates the wheel 14, bringing the carbons nearer
together, and restoring the are to its proper length; when this is done the cur-
rent becoming normal, the solenoid 30 attracts its core and restores all the parts
of the gearing to their normal position.
With the mechanism described, the feeding of the carbons is so gradual and
is so accurately in accord with the requirements, that there is almost no varia-
tion in the amount of current taken by the lamp.
While I have described specific details in carrying out my invention, I desire
it to be understood that changes may be made therein without departing from
the spirit and scope of the invention, and consequently I do not desire to be
limited to the details of construction shewn and described.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, as communicated to
me by my foreign correspondents, I declare that what I claim is :-
1. In an arc lamp an operative solenoid the magnetic core of which has a
spring connection with the operating lever there being lost motion between
these parts and a yielding resilient cushion or cushions interposed between the
metal pieces, substantially as described and for the purpose specified.
2. For an arc lamp, a dash-pot for retarding the motion of the operating lever
in which one of the bearing surfaces or the plunger itself is made of graphite,
substantially as described.
and
3. An arc lamp having its operative solenoid the dashpot partially sup-
or
ported by a yielding resilient cushion, substantially as described.
4. An arc lamp constructed and operating substantially as described with
reference to the accompanying drawing.
Dated the 30th day of November 1898.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.