Improvements in the Construction of Electric Arc Lamps.
Year: 1895

page_text: Date of Application, 20th Feb., 1895
Complete Specification Left, 8th Aug., 1895-Accepted, 14th Sept., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Electric Arc Lamps.
I, THOMAS SEDGWICK FOSTER of 38 Blackett Street, Newcastle-on-Tyne in
the County of Northumberland, Electrical Engineer do hereby declare the nature
of this invention to be as follows
This invention relates to electric are lamps and consists in an improved construc-
tion for employing a solenoid for the regulation of the distance between the
carbons.
The solenoid is formed of a tube slotted along its entire length and surrounded.
by a belically coiled wire. At the lower end of this solenoid is a cross piece which
carries on each side of said solenoid, a pulley, an insulated binding screw, an
insulated downwardly projecting rod, and a lug for attachment of the outer globe.
These downwardly projecting rods are connected at their lower ends by a cross bar,
and upon them slide two sleeves connected below by a cross piece carrying a socket
into which the lower carbon is fitted. Within the solenoid slides a core or armature
preferably of soft iron and this core carries at its lower end a socket for reception of
the upper carbon and two. lugs to which cords are respectively attached these cords
The
being passed over the aforesaid pulleys and connected to the sliding sleeves.
coil of the solenoid is connected at one end to a binding post at the upper end of
the slotted tube and at the other end to one of the binding posts on the cross piece
at the lower end of the solenoid. The other binding post on this cross piece is
electrically connected with one of the downwardly projecting rods. The weight of
the core or armature and its connected parts is somewhat greater than the weight
of the frame carrying the lower carbon; thus the carbons tend to rest in contact:
until on passage of the current the armature is retracted and the carbons separated.
Dated this 20th day of February 1895.
HERBERT HADDAN & Co.,
Agents to Applicant.
Improvements in the Construction of Electric Arc Lamps.
I, THOMAS SEDGWICK FOSTER of 38 Blackett: Street, Newcastle-on-Tyne in
the County of Northumberland, Electrical Engineer, 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 :-
This invention relates to electric arc lamps and consists in an improved
construction for employing a solenoid for the regulation of the distance between
the carbons.
The solenoid is formed of a tube or bobbin holder which may have a solid wall
for lamps using a continuous current or may be slotted or split along its entire
length where alternating currents are used and is surrounded by a helically coiled
wire. At the lower end of this solenoid is a cross piece which carries on each side
of said solenoid, a pulley, an insulated binding screw, an insulated downwardly
projecting rod and if desired a lug for attachment of the outer globe. These

page_text: downwardly projecting rods are connected at their lower ends by a cross bar, and
upon them slide two sleeves connected below by a cross piece carrying a socket for
holding the lower carbon. Within the solenoid slides a core or armature preferably
of soft iron and solid if for continuous current lamps, or of a laminated type if for
alternating current lamps. This core carries at its lower end a socket for reception
of the upper carbon and two lugs to which cords are respectively attached these
cords being passed over the aforesaid pulleys and connected to the sliding sleeves.
The weight of the core or armature and its connected parts is somewhat greater
than the weight of the frame carrying the lower carbon. Thus the carbons tend to
rest in contact until on passage of the current the armature is retracted and the
carbons separated.
The circuit is thus broken. Owing to the action of gravity they will be imine-
diately drawn together again and the circuit renewed.
The action will thus consist of a series of separations and connections, and
comparative equilibrium will be established thus ensuring a steady and uniform
light.
The annexed drawing shows a side elevational view of the improved lamp.
A is the soft iron core, solid or laminated, B. solenoid fixed to plate J by bolts P.
F is the upper carbon holder fixed to core A by screw or otherwise.
M. M', are terminal binding posts, K, bolts passing through tubes N, or N might
be solid rods with the ends turned smaller and screw-threaded. T is a distance
piece or tie S sleeves fixed to cross bar D which carries or is part of lower carbon
holder F. R cords or chains carried over pulleys H supported by plate J and
connecting parts S and F together. The conducting wire from post M is taken to
rod K, that from solenoid B to post M¹.
The starting end of wire of the solenoid is soldered or fixed into the upper end
of the bobbin. Insulation is provided where rod K passes through J and where
cords or the like R are secured to sleeves S. L are the carbons. The current
entering at post M' will pass through parts B, A, L, L, D through the left hand
sleeve to S, tube N, and rod K and to terminal post M completing the circuit.
In the drawings the core of the solenoid is shown solid and thus acts very satis-
factorily for direct current, but for alternating currents the core is kept cooler by
being of the laminated type also in this case the bobbin on which the wire is wound
should be split from top to bottom. A solid bobbin and solid core act very satis-
factorily for the direct current but for alternating current a bobbin with slot from
top to bottom and laminated core are recommended.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed I declare that what
I claim is
The construction of the electric are lamp substantially as herein described whereby
the separation of the carbons is controlled by the action of gravity and the
magnetization of the solenoid core.
Dated this 8th day of August 1895.
HERBERT HADDAN & Co.,
18 Buckingham Street, Strand, London, "W.C.,
Agents to Applicant.