An Improvement in Electric Switches.
Year: 1893

page_text: COMPLETE SPECIFICATION.
An Improvement in Electric Switches.
I, EDWARD LIONEL JOSEPH, of 92 Queen Victoria Street, in the City of
London, Engineer and Electrician, 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, reference being had to the accom-
panying sheet of drawings, and to the letters and figures marked thereon, that is
to say :-
This invention relates to that kind of switch in which segmental contact plates
are secured on an earthenware or other insulating base, and the connecting piece
for closing the circuit between such contact plates when required consists of a
crossbar mounted on a central thumb piece which can be turned on its centre to
bring the said connecting piece into or out of contact with the contact plates on
the base.
Heretofore the connecting piece on the central thumbpiece has been made of a
solid and rigid piece of metal usually a brass casting for example. Now my
improvement consists in making the said connecting piece of comparatively thin
sheet metal turned or folded, and preferably split, at the ends so as to be more or
less flexible in order that such ends may yield more or less when pressed between
the contact surfaces of the contact plates.
In the drawings hereto annexed
Figure 1 is a plan, with the cover removed, of a switch having my improvement
applied thereto.
Figure 2 is an elevation of same, the cover being shown in dotted lines, and
Figure 3 shows the central thumbpiece with my improved connecting piece
detached from the switch.
A is the base of the switch constructed of earthenware, wood or other insulating
material in the usual way. B B are the fixed contact plates secured to the base A
in the usual way, the conducting wires being led through the holes CC' respectively
in the base A to the binding posts B* B* respectively of the said contact plates.
D is the usual thumbpiece turning on the centre pin E and having secured to it
the connecting piece F composed of a piece of sheet metal the ends of which are
bent or folded and preferably split as shown in Figures 2 and 3. In Figures 1
and 2 the thumbpiece D and connecting piece F. are shown in the position they
occupy when out of contact with the contact plates B B' but when the said thumb-
piece and conuecting piece are turned in the direction of the arrow in Figure 1,
the bent ends of the connecting piece F pass in under the contact plates B B' as
shown in dotted lines in Figure 1 and being more or less flexible accomodate them-
selves to the form of such plates and make good electrical contact therewith at
both ends. The thumbpiece D and connecting piece F are returned definitely to
their normal or out of contact position, that is into the position shown in full lines
in Figures 1 and 2 as soon as they are turned in the direction opposite to the arrow
clear of the contact plates B B', by the spring G acting on the pins G¹ G on the
connecting piece F in the usual and well understood way. H represents the cover
of the switch which may be secured to the base A by a bayonet joint, by screwing,
or otherwise, in the usual way.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
In an electric switch constructing the connecting piece for closing the circuit

page_text: through the contact plates of sheet metal bent at the ends, as hereinbefore
described, and illustrated in the drawings and for the purpose specified.
Dated this Sixth day of March 1893.
E. L. JOSEPH,
Per W. H. Beck,
115, Cannon Street, London, Agent.
E. L. JOSEPH,
Per W. H. Beck,
115, Cannon Street, London, Agent.