Improvements in or connected with Electric Arc Lamps.
Year: 1897

page_text: Improvements in or connected with Electric Arc Lamps.
I, FREDERIC STANHOPE WORSLEY, of 119, Church Lane, Charlton, in the County
of Kent, Electrical Engineer, do hereby declare the nature of this invention to be
as follows: -
In electric arc lamps as at present constructed a dash-pot is used for the pur-
pose of damping the movement of the regulating solenoid at the time of striking
the arc, but this damper is objectionable during the feeding of the carbons in the
normal working of the lamp. The object of my invention is to provide means
by which the necessary damping effect is obtained at the time of striking the arc
whilst the feeding of the carbons in the normal working of the lamp is not inter-
fered with thereby.
According to my invention I provide a device which during the feeding of the
carbons in the normal working of the lamp is inoperative but which when the
arc is being struck is so acted upon by some part in connection with the feeding
mechanism that the said device then operates as a damper to prevent the too vio-
lent movement of the mechanism. The said device may be arranged in any
convenient way to fulfil the foregoing conditions; for example, it may consist of
an air chamber formed by a portion of the interior of the solenoid or by a continua-
tion thereof and containing a piston or diaphragm with which the core of the
solenoid comes in contact when the arc is being struck so that the air is com-
pressed and acts as a damper of the movement of the core and consequently of the
feeding mechanism. The piston or diaphragm is so supported or arranged that
it follows the return movement of the core only sufficiently to be in readiness for
the next operation so that the core is independent of it during the normal feeding
of the lamp. To ensure the return of the piston or diaphragm it may be provided
with a piece of magnetic metal which under the influence of the current around
the solenoid will be attracted and ensure the said return.
Dated this 10th day of June 1897
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
In electric arc lamps as at present constructed a dash-pot is used for the purpose
of damping the movement of the regulating solenoid at the time of striking the
are but this damper is objectionable during the feeding of the carbons in the
normal working of the lamp. The object of my invention is to provide means
by which the necessary damping effect is obtained at the time of striking or open-
ing the arc whilst the feeding of the carbons in the normal working of the lamp
is not interfered with thereby.
According to my invention I provide a device which, during the feeding of the
carbons in the normal working of the lamp, is inoperative, but which, when the
are is being struck or opened, is so acted upon by some part in connection with
the feeding mechanism that the said device then operates as a damper to prevent
the too violent movement of the mechanism. The said device may be arranged
in any convenient way to fulfil the foregoing conditions; for example, as shewn in
the accompanying drawings, which are vertical sections of solenoids provided with
my improvements, it may consist of an air chamber or dash-pot A formed by a
portion of the interior tube A of the solenoid, or by a continuation thereof, and
containing a piston or diaphragm B with which the core C of the solenoid ]) comes
in contact when the arc is being struck or opened so that the air in the chamber A¹
is compressed and acts as a damper of the movement of the core and consequently
of the feeding mechanism. The piston or diaphragm B is so supported or arranged
that it follows the return movement of the core C only sufficiently to be in
readiness for the next operation so that, as shewn in Figure 1, the core is inde-
pendent of it during the normal feeding of the lamp. In the arrangement shewn
in the drawings an annular shoulder or projection a in the tube A serves to
support the piston or diaphragm out of contact with the core C during the normal
feeding of the lamp as shewn in Figure 1, the said piston or diaphragm coming
into operation only when the arc is struck or opened; Figure 2 shews the device
as when operated in this manner.
To ensure the return of the piston or diaphragm B, it may, as shewn in the
drawings, be provided with a piece of magnetic metal b which, under the influence
of the current around the solenoid D, will be attracted and ensure the said return;
or this return may be effected by a spring adapted to bear on the end of the
piston or diaphragm B opposite to that on which the core C acts.
Instead of arresting the descent of the piston or diaphragm B by the shoulder a
as hereinbefore described, I may attain the same result by connecting the
said piston to the closed end of the dash-pot. or air chamber A' by a flexible
cord or the like, or any other suitable stop device may be provided for that
purpose.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. In an electric arc lamp the combination with a solenoid having a dash-pot,
of a piston or diaphragm not positively connected to, but adapted to be operated
by the core of the solenoid substantially as herein before described with reference
to the accompanying drawings.
2. In an electric arc lamp the combination with a solenoid and a dash-pot
having a piston or diaphragm not positively connected to the core of the solenoid,
of a block or piece of magnetisable material or a spring for returning the said
piston or diaphragm to its normal position substantially as hereinbefore described
with reference to the accompanying drawings.
3. In an electric arc lamp the combination with a solenoid and a dash-pot
having a piston or diaphragm not positively connected to the core of the solenoid,
of a stop device for supporting the piston or diaphragm out of contact with the

page_text: core of the solenoid during the normal feeding of the lamp substantially as herein-
before described with reference to the accompanying drawings.
Doted this 12th day of April 1898.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.