AN ELECTRIC SWITCH
Year: 1884

page_text: I, EDWARD FREDERICK HERMANN HEINRICH LANCKERT of Charlton in the
County of Kent, Electric Engineer do hereby declare the nature of the said
Invention for "AN ELECTRIC SWITCH" to be as follows:-
In closing and opening electrical circuits by switches making and breaking
contact of metallic surfaces, sparks are produced which have a destructive action
on the contact surfaces, especially in cases whero very considerable electric currents
are dealt with.
My Invention relates to a construction of switch such that the metallic contacts
are not subject to this destructive action, the sparking, if any, taking place between
carbon surfaces which can be readily renewed, leaving the metallic surfaces sound
without corrosion or oxidation.
Ono
For this purpose, I attach to the handle or lever by the movement of which the
one metallic surface is brought into contact or removes out of contact with the
other, a stick of carbon which may be such as is used in arc electric lamps, and to
the other or stationary contact surface I attach another stick of carbon.
of these carbon sticks, either that attached to the moveable or that attached to the
stationary part of the switch, is fixed in a spring-holder which can yield a certain
distance, while it keeps the carbons in contact, but which, when the movement is
carried beyond this distance, meets with a stop which prevents the one carbon from
farther following up the other. Thus, assuming the metal surfaces to be bearing
on each other making intimate contact for passage of current, the carbons are also
bearing against each other subject to the pressure of the spring, and therefore
forming a conductor for part of the current. On now moving the handle or lever
of the switch so as to withdraw the metal surfaces from contact, the carbons
continue still to be pressed together by the spring and continue to form a conductor
for the current after the .metal surfaces are quite separated. But on moving the
lever or handle still farther, the carbuns themselves become separated, and the
circuit is opened. In like manner, in the act of closing the circuit, the. carbons
first. come into intimate contact forming a conductor, and then, by a farther
movement of the handle or lever, the metallic surfaces are brought into contact.
The metal surfaces employed may be of any known form employed for making
electrical contact; for example, one may be a taper plug, the other a taper hole
for its reception, or either or both may be springs pressed against or rubbing over
each other.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.

page_text: I, EDWARD FREDERICK HERMANN HEINRICH LANCKERT of Charlton in the
County of Kent, Electrical Engineer, do hereby declare the nature of my Invention
for "AN ELECTRIC SWITCH" and in what manner the samo is to be performed
to be particularly described and ascertained in and by the following statement :-
In closing and opening electrical circuits by switches making and breaking
contact of metallic surfaces, sparks are produced which have a destructive action
on the contact surfaces, especially in cases where very considerable electric currents
are dealt with.
My Invention relates to a construction of switch such that the metallic contacts
are not subject to this destructive action, the sparking, if any, taking place between
carbon surfaces which can be readily renewed, leaving the metallic surfaces sound
without corrosion or oxidation,
For this purpose, I attach to the handle or lever by the movement of which the
one metallic surface is brought into contact or removes out of contact with the
other, a stick of carbon, which may be such as is used in arc electric lamps, and to
the other or stationary contact surface, I attach another stick of carbon. One of
these carbon sticks, either that attached to the moveable or that attached to the
stationary part of the switch, is fixed in a spring holder which can yield a certain
distance, while it keeps the carbons in contact but which when the movement is
carried beyond this distance meets with a stop which prevents. the one carbon from
farther following up the other. Thus, assuming the metal surfaces to be bearing
on each other making intimate contact for passage of current, the carbons are also
bearing against each other subject to the pressure of the spring, and therefore
forming a conductor for part of the current. On now moving the handle or lever
of the switch so as to withdraw the metal surfaces from contact, the carbons
continue still to be pressed together by the spring and continue to form a conductor
for the current, after the metal surfaces are quite separated. But on moving the
lever or handle still farther, the carbons themselves become separated, and the
circuit is opened. In like manner, in the act of closing the circuit, the carbons
first come into intimate contact, forming a conductor, and then, by a farther
movement of the handle or levor, the metallic surfaces are brought into contact.
The metal surfaces employed may be of any known form employed for making
electrical contact; for example, one may be a taper plug the other a taper hole
for its reception, or either or both may be springs pressod against or rubbing over
each other.
Fig. 1 of the accompanying Drawings is a section of ono form of electric switch
embodying any Invention. On a base A of insulating material is mountod a lever B
which by means of a hand lever C acting on the curved arm of B can be depressed
to the position shewn in which position the bulb D attached to the lever B is
pressed into the cup E making intimate contact so that there is complete conduction
from L to L'. On pulling back the hand lever C, a pin F on its arm raises tho
lever B, breaking the contact of D and E. In order to avoid the sparking and its
consequences, I fix in the bulb Da stick G of carbon, securing it therein by a
screw nozzle pressing on a packing of copper wire rope, and in the socket I of a
spring H which is attached by a nut to the tubular stem of the cup E I fix another
carbon stick K which passes through the stem of E and is pressed by the spring
against G. After contact of D and E is broken the carbon K follows the carbon G
maintaining contact with it until the socket I comes to bear against the stem of E

page_text: when they separate and the circuit is completely broken. And similarly in the act
of closing the circuit, the two carbons G and K first come into contact before D
reaches E
Fig. 2 is a section and Fig. 3 a plan of a modified form of electric switch
embodying my Invention. On a base A of insulating material is mounted a
spindle B, which can be turned by a handle C.. On this spindle are fixed a number
of bent metallic springs D which in the position shewn in Fig. 3 press upon two
metal plates E and E completing circuit through them. On a bracket of the
plate E is fixed a carbon stick K and on an arm M is fixed another carbon stick G.
The arm M is free to revolve to a certain extent on the spindle B having in its
central part two slotted recesses through which pass pins N N attached to the
spindle. A spring H connects the arm M to an arm O projecting from and
turning with the spindle B. On turning the spindle in the direction of theo
arrow P, the springs D are in the first place withdrawn from contact with E', the
spring H still keeping the carbon G pressed against K, and not until the pins N
reach the ends of the slots in M is G withdrawn from K.
In some cases the switch has to be arranged so as to pass the current through
either or both of two conductors. Fig. 4 is a section, Fig. 5 is a plan and Fig. 6 is
a sectional plan of an electric switch embodying my Invention, suited for
completing circuit from L through either or both of the conductors L'or L³. In
this case the spindle B mounted in the base A and turned by the handle C carries
a segment D, which in the position shewn in Fig. 5 is pressed between the plate E
and the spring plate E' connected to the one conductor L' and also between E³
and connected to the other conductor L. Within a casing below the base A aro
fixed two carbons K' K³ in brackets connected respectively to E' and E, and two
other carbons G Gare fixed in levers I¹ 12 that are pressed by springs H'H²
against K' K² respectively.
On the spindle B is fixed a cam Q, the protuberances of which, when the
spindle B has been turned to a certain extent in either direction come to bear
against rollers mounted on the lever 1' or 13 as the case may be, so as to withdraw
the carbon G¹ or G from K' K' but not till after the sogment D has been
withdrawn from contact with E or E¹.
Having thus 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, providing, besides the usual metallic contact surfaces,
carbons which are pressed together by springs and are so arranged as not to bo
separated until after the metallic contacts are completely broken, substantially as
and for the purposes herein set forth.
L
1001
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.