Improvements in Circuit Controllers or Switches for Incandescent Electric Lamps.
Year: 1890

page_text: Improvements in Circuit Controllers or Switches for Incandescent
Electric Lamps.
I, NORMAN MARSHALL, of 1320 Wallace Street, City and County of Philadelphia,
State of Pennsylvania, United States of America, 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 especially to a device for controlling the electric circuit of
incandescent electric lamps; and it consists in certain novel features hereinafter fully
set forth the object being to produce a simpler, cheaper and more effective device of
this character than is now in ordinary use.
The nature and operation of the improvement will be readily understood by all con-
versant with such matters from the following explanation.
In the accompanying drawing,
Figure 1 is a plan view of my improved switch the cap being removed.
Figure 2 a vertical transverse section of the same, the cap and key being in
position; and
Figure 3 a plan of the cain.
Like letters and figures of reference indicate corresponding parts in the different
figures of the drawing.
In the drawings, A represents the bed or bed-plate which is preferably circular in
plan view and has an annular groove or rabbet, 6, on its upper edge to receive the
enclosing cap B.
The underside of the plate is chambered at d. Openings fare formed in the
plate to receive attaching-screws. Disposed centrally on the upper face of the base
plate there is a circular cam D provided with four vertically-inclined tracks ghij.
The body of this cam is constructed of porcelain, glass or similar non-conducting
material.
A plate m of brass or similar conducting material is secured to the face of the bed
plate A, and is extended to cover the inclined face of the track i.
A similar plate p
secured at the opposite side of the cam and is extended to cover the face of the
track, d, of said cain.
Openings g for the line wires are formed through the plates m p and base A and
binding-screws are turned into said plates near said openings, said screws formning
connectors for securing the line-wires in contact with the plate.
A vertically-arranged spindle Cheaded at, on its lower end passes centrally through
the cam and is fitted to rotate in the base A.
A cap is turned onto the upper end of said spindle which is threaded to receive
it. An insulating thumb piece y, is mounted on the upper end of the spindle. The
body of the spindle is flattened at and a horizontally arranged contact plate H, is
mounted loosely thereon in position to engage the faces of the cam tracks, ghi j.
The flattened portion of said spindle preventing it from rotating in said spindle.
A stiff-coiled spring a, is mounted on the spindle C between the cap and plate H,
said spring acting expansively to force said plate into engagement with the cam.
In the use of my improvement when the contact plate H is in engagement with the
faces of the cam-tracks g i, the circuit is closed between the plates m p.
To break the circuit, the key is rotated from left to right. causing the contact
plate, H, to ride the tracks, gi, until it passes the vertical ends, 15, of said tracks
when the spring, x, acts to force it immediately downward into engagement with the
insulating tracks hy instantly breaking said circuit.
By rotating the contact plate in like manner until it passes over the corresponding

page_text: ends of said insulating tracks and is forced into engagement with the tracks gi, the
circuit may be again closed.
By the use of the cam and the spring-actuated contact-plate, as described, a positive
action is employed in making and breaking the circuit and the contact broken so
abruptly that all danger of the currents arcing is overcome. It will be understood
that more than four cam tracks may be employed if desired, as by using eight tracks
and two contact plates the device is applicable to a double pole switch.
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 1
claim is :-
First. In a device of the character described, an insulating base; a circular cam
thereon provided with four equidistant vertically-inclined tracks; a rotary key and
contact plate mounted loosely thereon; a spring for forcing said plate into engage-
ment with the face of said track and connectors for the line wires, said connectors
being extended to cover the working faces of alternate cam-tracks substantially as
described.
Second. The combination of the base-plate with a four-track cam secured thereon,
alternate tracks being in electrical connection with the line-wire binding posts sub-
stantially as described.
Third. The combination of the base-plate with a circular cam secured to said plate,
the face of said cam being divided into four or more vertically-inclined tracks and
alternate tracks being in electrical connection with the line-wire binding posts sub-
stantially as described
Fourth. The combination of the base-plate with a four-track cam alternate tracks
being in electrical contact with the line wire connectors; a contact-plate; a key for
rotating said plate and a spring for holding the plate in engagement with said tracks
substantially as described."
Fifth. The base-plate and four-track circular cam in combination with the wire
connectors elongated to cover the faces of alternate cams; the key and the spring-
pressed contact plate fitted to slide on said key and be rotated thereby substantially as
described.
Sixth. In a circuit controller for incandescent electric-lights, the cam H, provided
with the vertically inclined tracks ghij; alternate tracks having their faces in
electrical contact with the line wire binding posts substantially as described.
Seventh. In a circuit controller for incandescent electric-lights the base-plate and
the four-track cam in combination with a spindle fitted to rotate in said base and a
spring-pressed contact plate in engagement with said tracks, said plate being fitted to
slide on the spindle and be rotated thereby substantially as set forth.
Eighth. In a circuit controller for incandescent electric-lights the base-plate and
flattened rotary spindle, C, in combination with the four-track cam, alternate tracks
being in electrical contact with the wire connectors and the spring-pressed contact
plate H, fitted to slide vertically ou said spindle substantially as described.
(
Dated this 4th day of December 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.