Improvements in Electric Switches.
Year: 1899

page_text: Date of Application, 8th May, 1899-Accepted, 19th Aug., 1899
COMPLETE SPECIFICATION.
Improvements in Electric Switches.
We, JAMES ERNEST SPAGNOLETTI and JOSEPII CROOKES, Electrical Engineers,
of Goldhawk Works, Goldhawk Road, London, W., do hereby declare the nature
of this invention and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement:.
-
Our invention relates to improvements in electric switches and has for its
object to provide an improved "series-parallel" switch for use in connection
with incandescent electric lamps and by means of which the lights can be
lowered when required without leaving the place in total darkness and which
will work at the lower candle power without any appreciable loss of power.
The way in which we carry out our invention is as follows, reference being
made to the accompanying drawings in which Figure 1 is a plan of our improved
switch with the cover removed, and Figure 2 a side view of same.
The same letters refer to the same parts in the two figures.
On a base a of earthenware or other suitable insulating material we provide
6 contact terminals b, c, d, b, c, d, and on a central pin or pivot e a cross-
bar f of insulating material; surrounding the pin or pivot e and above the cross-
barf is a spring 9 bearing at each end on a ring or washer the lower ring bear-
ing on the cross-bar or lever f. The cross pin retains the spring g
in position at the top. On the base a two oppositely inclined cam
surfaces are provided for the purpose of ensuring a quick break off
position of the cross-bar or contact lever f, & for raising same into contact
making position when the switch handle is operated; the contact lever f has
projections, one at each end, on its under side and recesses or indenta-
tions, m m¹ are provided on that part of the base a on which the cam
surfaces are formed in which recesses the projections ¹ respectively take
when the contact bar or lever f is in either of its lighting positions. n is a
handle which engages lever f for the purpose of operating the switch.
The working of our invention is as follows:-
In the normal position (lights out) the contact bar or lever f is at the lowest
part of the inclined or cam surfaces ; the shoulders o o' (Fig. 1) forming
stops for it in this position. Assuming that it is desired to light a pair of lamps
which are in parallel, the switch handle n is turned and moves contact lever f
up on the inclined or cam surfaces j j¹ and the contact strips or brushes f¹ fa
into contact with terminals bc, b₁ c¹, respectively, the projections on the
under side of said contact lever dropping or being pressed into the recesses l m¹
respectively under the influence of the spring which is compressed as the
lever f moves up on the cam surfaces; the lights are now on in the series
position, and if it is desired to change them to parallel the switch handle is
further turned or operated and moves the contact lever f and its contact strips
or brushes f f to make contact with terminals cd, respectively (cutting
out terminals and c¹) the projections moving into the recesses or indenta-
tions m, these recesses 1 1¹, m m¹ retaining the switch in either of its light-
ing positions. A reverse movement of the switch handle returns the contact

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lever to its former positions, that is either "series or "off" as the case may
be. The connections to the lamps are shewn in dotted lines in Fig. 1, and the
contact lever in the "off" position.
Variations may be made in the switch without departing from our invention.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is: :-
An electric switch consisting of a base having inclined or cam surfaces, a
central pivot and a contact bar or lever mounted thereon said lever being pro-
vided with contact strips or brushes, a spring on said central pivot or pin, and
contact terminals on the switch base, all arranged and operating substantially
as described with reference to the accompanying drawing and for the purposes
specified.
JOHN P. O'DONNELL, Fel. Chart. Inst. P.A.,
Agent for Applicants, 70 and 71, Palace Chambers, Westminster, S.W.