An Improved Switch for Incandescence or Glow Electric Lamps in which the Filament is Subjected to a Preliminary Heating Effect apart from the Lighting Current.
Year: 1898

page_text: Date of Application, 17th Nov., 1898
Complete Specification Left, 16th Aug., 1899-Accepted, 4th Nov., 1899
PROVISIONAL SPECIFICATION.
An Improved Switch for Incandescence or Glow Electric Lamps in
which the Filament is Subjected to a Preliminary Heating Effect
apart from the Lighting Current.
I, HUGO HIRST, of 69, 71, 88, 92, Queen Victoria Street, in the City and County
of London, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to an improved switch for controlling the double circuits
in the case of incandescence or glow electric lamps in which the filament is when
cold practically a non conductor, but when heated by reason of its proximity to
a heated conductor upon a separate circuit, becomes sufficiently conductive to be
maintained in a state of incandescence by the other circuit, both being coupled
to the mains. It is obvious that the heating circuit may be broken when the
lighting circuit is fully established and the object of my invention is to effect
this dual operation by one movement.
In carrying my invention into practice, I arrange the switch to close both
circuits when the lamp is to be lighted. For purposes of description, these
two circuits, both derived from the main leads are called the "heating circuit"
and the "lighting circuit." When both are closed in reality the "heating
circuit" alone is closed, the "lighting circuit" not being properly closed until
the filament has become sufficiently heated to become a conductor, and raised to
incandescence, or a high degree of luminosity.
I employ two contact bars, having a common axis upon which they rotate, to
engage with the several fixed contact plates studs or the like upon the switch
base. Both bars are so arranged to make contact at one end with the same plate
or atud or separate studs or plates electrically connected, which may hereinafter
be called No. 1 contact. The other ends of both bars make contact with separate
studs, hereinafter called Nos. 2 and 3 contacts. The upper bar upon the common
axis is arranged to be partially rotated independently of the lower bar, and is
brought to a definite position off the contacts Nos. 1 and 2 by a returning spring
fixed in tension between the two bars. The handle or key is preferably attached
to the upper bar. Said upper bar is made wide near the centre so that two stop
pins or projections may he attached to or formed thereon, to engage, (either one
according to the direction of movement) with the lower bar, when the upper bar
has moved through a predetermined portion of its path. The main leads are
connected to No. 1 contact, No. 2 is coupled to the "heating circuit" and No. 3
to the "lighting circuit," the return being carried direct or through a similar
switch.
When the switch is operated the first movement of the upper bar causes one
of the projections or pins to engage with the lower bar, after which both bara
move together, until their ends upon one side of the axis are upon contacts No. 1
and on the other side contacts Nos. 2 and 2 respectively, thus closing the heating
and lighting circuits. Directly the action of the "heating current " has raised

page_text: the temperature of the filament to incandescing conductivity, which is momentary,
the operator releases the handle or key of the switch, and the spring under tension
between the two levers forces the upper bar off the studs or contacts Nos. 1 and 2.
thus opening the "heating circuit," the handle or key being then turned slightly
in the same direction to establish the "lighting circuit." The opposite pin now
engages with the lower bar, which then travels with the upper bar until by
clearing contacts 1 and 3 the heating circuit is opened. I may use a spring or
like device for holding the lower bar in the "on" position, and may modify the
general arrangement of parts to suit various conditions of application without
departing from the essential features of my said invention.
"
COMPLETE SPECIFICATION.
An Improved Switch for Incandescence or Glow Electric Lamps in
which the Filament is Subjected to a Preliminary Heating Effect
apart from the Lighting Current.
I, HUGO HIRST, of Nos. 09, 71, 88, 92, Queen Victoria Street, in the City and
County of London, 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 satement:-
My invention relates to an improved switch for controlling the double circuits
in the case of incandescence or glow electric lamps in which the filament is when
cold practically a conductor of the second class as ordinarily designated, or
otherwise a bad conductor under the normal atmospheric temperature. When
heated by reason of its proximity to a heated conductor upon a separate circuit,
it becomes sufficiently conductive to be maintained in a state of incandescence by
the heating circuit, both being coupled to the mains. It is obvious that the
heating circuit may be broken when the lighting circuit is fully established, and
the object of my invention is to effect this dual operation by one movement.
In order that my invention may be clearly understood, I have appended the
accompanying sheet of drawings in which Figure 1 shows both circuits open
Figure 2, shows the lighting circuit on and the heating circuit cut off, and
Figure 3 shows the heating circuit closed the lighting circuit to be operative
directly the filament has reached the temperature of conductivity by radiated
heat. "Similar letters of reference indicate corresponding parts throughout the
several drawings.
In carrying my invention into practice, I arrange the switch to close both
circuits when the lamp is to be lighted. For purposes of description, these
two circuits, both derived from the main leads are called hereinafter the "heat
ing circuit" and the "lighting circuit" respectively. When both are closed,
in reality the "heating" circuit alone is closed, the "lighting" circuit not
being properly closed until the filament has become sufficiently heated to be a
conductor, and raised to incandescence or a high degree of luminosity.
I employ two contact bars, mounted upon a common axis A,, and shown
respectively by B B, and. they rotate upon that axis A so as to engage with
the contacts D, E, F, which are fixed upon the base C in the manner of ordinary
switch blocks or contacts. Both bars B B are arranged to- make contact with
the same contact plates or studs, D, E, F, Both bars B and B are so arranged

page_text: to make contact with the plate Fat one end. The other ends of both bars B B¹
make contact with plates or studs B E. The upper bar B¹ upon the axis A is
arranged to be partly rotated independently of the lower switch bar B, and is
brought to a definite position relatively to the contacts D E and F by a spring S
fixed in tension between the two bars B B¹. The handle or key or other device
for affording the requisite action is preferably attached to the upper bar B¹³,
which carries two stop pins or projections a b to engage (either one according to
the direction of movement) with the lower bar B, when the upper bar B¹ has
moved through a predetermined portion of its path. The main leads are con-
nected to contacts E and F and include the heating circuit H, D being connected
with the filament or lighting circuit f, a common return lead serving both circuits.
In operating the switch, the bars B and B make contact normally with the
plate F, and are so formed that B¹ may make contact with the plate or stud E,
but by reason of its length clears the plate or atud D, which is covered by the
bar B when in the position of contact as shown by Figure 2. One of the leads is
connected to the segmental plate F common to both bars B₁ and B, and the
other lead a passes through the "heating circuit" H and so to the plate or
stud E, the filament or "lighting circuit "f being coupled to d and also to the
contact plate or stud D, within the range of the bar B. Referring now to
Figure 1, in which both circuits are shown open, a koy or handle is applied to
the bar B', which is moved in the direction of the arrow, as shown, dragging B
with it by the tension of the spring S until B is brought to rest against the stop
pin g where contact is established between F and D, which practically puts the.
filament or "lighting circuit" into operation. Now this is shown by Figure 2
and a further movement in the direction of the arrow of B₁ brings the stop or
projection a on B₁ against B, and then the further movement of B¹ to make
contact with the plate or stud E is against the tension of the spring S, and as
the preliminary "heating circuit" H is only required momentarily to establish
the proper conductivity of the filament or "lighting circuit" f," the spring S
causes the bar B¹ to drop back from the position shown by Figure 3 to that of
Figure 2 the heating circuit H being thus automatically cut off when the handle
or key is released. The lower bar B having been placed in position of contact
between D F and f, maintains the "lighting circuit" whilst the bar B¹ is in the
position of Figure 2. The return movement of B¹, causes the pin or projection b
to engage with B and put both bars B¹ B-in the position shown by Figure 1,
when both circuits H and f are open.
The feature of the invention is in the establishment of the "heating circuit" H
only by holding the handle or key controlling the bar B' with its stops a buntil
the required temperature of the "lighting circuit" or filament f is attained, and
when released said "heating circuit" H is automatically cut off by the spring S
without disturbing the position of the bar B which maintains the lighting
circuit.
I wish it to be understood that the two levers with the spring connection
and stops to effect the required contacts are not necessarily operated by a key
or lever in a circular direction but may be adapted to any vertical, horizontal or
angular action such as tumbler, push, hatchet or other movements with contacts
to correspond thereto.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
First. In a switch for incandescence or glow lamps in which the filament is
subjected to a preliminary heating effect apart from the lighting circuit, the
use and arrangement of two switch bars B B¹ of different lengths, upon a common
axis A connected by a spring 8, and making contact with plates or studs D E F
and operated by any vertical, horizontal or angular action, as herein described.
Second. In a switch for incandescence or glow lamps in which the filament

page_text: is subjected to a preliminary heating effect apart from the lighting circuit the
method of and means for temporarily establishing the heating circuit and
automatically cutting it off when released, the lighting circuit remaining closed
substantially as herein described and shown by the appended drawings.
Third. In a switch as referred to in the preceding claims, the combination
of two bars of different lengths upon a common axis, connected by a spring and
stop pins with contact studs or plates controlling a heating and lighting circuit,
the heating circuit being automatically cut out as herein described and illus-
trated by the appended drawings.
1000
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicant.