Improvements in Electric Arc Lamps.
Year: 1894

page_text: Date of Application, 28th Feb., 1894
Complete Specification Left, 27th Nov., 1894--Accepted, 12th Jan., 1895
PROVISIONAL SPECIFICATION.
Improvements in Electric Arc Lamps.
JOHN CHARLES BOND ANDREWS 5 Melrose Gardens, W. Composer, do hereby
declare the nature of this invention to be as follows:-
An electric arc lamp in which the regulation of the arc is affected by an electro
magnet controlling a break band round a wheel over which also passes a band
carrying the carbons one at each end suitably held in holders & guided so that they
are in line with one another in the ordinary way. I usually construct the band or
break band of an elastic material or form such as a spiral spring being attached at
one end to the frame of the lamp and by the other to the armature or movable core
of the electro magnet. When the armature is attracted by the current it tightens
the spring band on the wheel and moves it round so as to separate the carbons &
form the arc. In so doing the break band expands and when the magnet relaxes
its pull the spring in contracting carries the wheel round sufficient to approach the
carbons the distance they have been consumed. To facilitate this action I weight
the falling carbon which gives the wheel a tendency to turn one way more than
the other. In addition to the spring band (or break band) I sometimes apply a
tape or wire band to the same wheel fixed to the core at one end and at the other
to a point near the other end of the spring band in such a way that the spring band
can elongate on the wheel before the rigid band is made to grip. By this additional
band the break has a more powerful grip after a certain point & makes the strike
of the arc more certain. The spring band above referred to may be constructed
with a shoe or shoes or links and springs. Instead of a band on the circumference
of the wheel I sometimes apply the brake on the side and in this case I prefer to
arrange a shoe or disc on each side coupled to the armature or core in such a
manner that when the core is moved in one direction the shoes tighten on the
wheel & carry it round & slacken away when the core moves in the opposite
direction. To deaden the sound produced by the electric arc I construct a compound
globe or lantern comprising two or more layers of glass or other transparent material
one within the other with an air space between: they may be permanently fixed
together or arranged to be seperated.
.......1001
J. C. BOND ANDREWS.
Improvements in Electric Arc Lamps.
JOHN CHARLES BOND ANDREWS of 12 Batoum Gardens London W. late of
Melrose Gardens London W. Professor of Music 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 an electric arc lamp in which the regulation of the arc
is effected by an electro magnet P. of Fig. 1 of the accompanying drawing,
controlling a brake band K, round a wheel H and attached to a spiral spring L

page_text: at the other end. Over the wheel H also passes a band G carrying the carbons
one at each end suitably held in holders E & F and guided so that they are in line
with one another. The carbons are made to approach and meet one another by the
preponderating weight of the top carbon holder.
When the current passes it circulates through the coil of the electro magnet P
which is thereby magnetised and attracts the armature N, by which through the
grip of the band K on the wheel H the carbons become separated and the electric
arc formed. As the arc lengthens by the consumption of the carbons, the current
is thereby weakened and the consequent reduction of the attraction of the magnet
for the armature N slackens off the brake band K to such an extent that the wheel
slips past & allows the carbons to approach. The adjustment of the movement of
the armature N to give the required degree of slip is effected by the adjusting screw M
to which the spring L is attached.
When several of the lamps are arranged in series I connect the electromagnet
as a shunt circuit to the arc and instead of its attractive force being arranged to
separate the carbons, I arrange it so that when the excitation is strongest
the armature releases the brake band off the wheel in opposition to the tension of
a spring which is arranged to tighten the band on the wheel and strike the arc.
I sometimes modify the construction of the brake device in the following
methods:-
:-
In that shown in Fig. 2, where the lettering is the same as in Fig. 1, I make
the brake band K compound consisting of a spiral spring of wire bearing on the
brake wheel and a non-elastic outside the spring. The spring and band are joined
together at each end in such a manner that the spring can elongate on the wheel
before the band is made to grip. By this means the brake band has a more
powerful grip after a certain point and the strike of the arc is made more certain.
The wire spring may be cylindrical or rectangular in section or it may be of rubber
or such like flexible material. I sometimes omit the non-elastic outside band and
use the spring band only.
At Fig. 3 is shown another modification of the brake. This consists of a
bar, K. carrying a brake shoe which bears against the brake wheel. The bar
hangs at one end from the armature N. and at the other from a spiral spring. The
action of this brake is similar to the preceding. Several links, or bars and shoes
may be employed instead of one.
At Fig. 4 is a modification in which the brake is made to grip the brake wheel
on the side, and then pull it round. The brake consists of a sling K consisting of
two bars hung from an armature N divided in two parts, and pivotted against V pole
pieces in the manner illustrated. The two sling bars are joined by a spring or
hinge at the bottom end and on their inner sides they have brake shoes which bear
against each side of the flange on the wheel H. The attraction of the magnet draws
the two halves of the armature N together, at the same time lifting them up and
turning the wheel.
The method may be applied without the use of the brake sling by arranging
the mechanism so that brake shoes on the armature may grip the wheel direct.
To deaden the sound produced by the electric are I construct a compound globe
or lantern comprising two or more layers of glass, shown in Fig. 1 at V. V., or other
transparent material, one within the other with an air space between them. They
may be permanently fixed together or arranged to be separated.
At Fig. 1 two glass V jars are shown but other shapes may be used as for
instance a V jar inside and a globe outside.
Reserving the right of varying the materials, forms, and proportions of an electric
arc lamp such as I have described :-and
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. The herein described method of regulating the arc by subjecting the pulley

page_text: carrying the suspended carbon holders to the action of a brake band tightened or
loosened by the varying attractive force of an electromagnet having its coils in series
or in shunt with the lamp circuit.
2. The operating as set forth in the preceding claim in combination with a
pulley carrying a band suspending the two carbon holders, a brake wheel on its
axis, a brake band having its one end attached to an adjustable spring, its other
end to the armature of an electro magnet subject to the lamp current substantially
as described.
3. The use and operating of a flexible brake band substantially as described, and
the modification thereof, also of a non-elastic brake band grasping a wheel with an
elastic face or surface in combination with the mechanism and for the purposes
hereinbefore set forth and described.
4. The use and operating of a combination as shown in Fig. 3 of the accompanying
drawing substantially as described and for the purposes aforesaid.
5. The use and operating of a combination for the purposes aforesaid, as shown in
Fig. 4 and the modification as described.
6. The use and operating of the silencing arrangement as described consisting of
two or more transparent cylinders jars or globes, surrounding the arc as hereinbefore
set forth and described.
Dated this 26th day of November 1894.