Improvements in Electric Switches.
Year: 1895

page_text: Date of Application, 6th July, 1895
Complete Specification Left, 4th Apr., 1896-Accepted, 20th June. 1896
PROVISIONAL SPECIFICATION.
Improvements in Electric Switches.
SEBASTIAN ZIANI DE FERRANTI, 27 Charterhouse Square, in the County of
London, Engineer and Electrician, do bereby declare the nature of this invention
to be as follows:-
This invention has for its object improvements in the construction of electric
switches especially applicable to the breaking of high tension currents.
According to my invention I make an electric switch with two paths one of
which is forined of any of the well known metal contacts, the other is through a
bar or spring projected from a bath containing oil or other insulating liquid and
The two
making contact with a piece of the switch above the insulating bath.
contact parts of the switch are in mechanical connection, when it is desired, to
break the current the switch handle is pulled down, the effect of this is first to
break the current carrying part of the switch, at the same time that this is going
on energy is being stored in a spring which works direct or controls the contact rod
above referred to. When the handle of the switch has got a little further and has
sufficiently well broken the circuit through the heavy current carrying parts of the
switch the mechanism operates a catch which releases the spring and shoots off the
contact rod. This rod leaves the contact above the oil bath and disappears into
the bath, its other end projecting through a gland and stuffing box in the bottom of
the bath.
The action of the switch is therefore first to separate the current carrying parts
without sparking and secondly to quickly break in air the current passing through
the remaining contact which in its turn is entirely immersed in the oil so as to
drown out any spark which may have a tendency to follow.
In some cases I may use the spring itself for carrying the lesser portion of the
current and for giving the quick break.
In some cases I may put the quick breaking gear into the oil or insulating bath
and actuate these parts by means of a reciprocating rod passing horizontally through
glands in the box.
Dated this 6th day of July 1895
трго
SEBASTIAN ZIANI DE FERRANTI of 27 Charterhouse Square in the County 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 :-
This invention has for its object improvements in the construction of electric
switches especially applicable to the breaking of high tension currents as shown on
the drawing.
Fig. 1 shows a section through the oil pot and spring gear leaving the catch
mechanism in elevation.

page_text: Fig. 2 shows a front elevation of the same.
Fig. 3 shows a view of one of the links.
Fig. 4 shows a view of the lever for compressing the spring.
According to my invention I make an electric switch with two paths one of
which is formed of any of the well known metal contacts as (a) the other is through
a bar or spring (6) projecting from a bath (c) containing oil or other insulating
liquid making contact with a piece of the switch (d) above the insulating bath, the
two contact parts (a and b) of the switch are in mechanical connection, when it is
desired to break the current the switch handle (e) is pulled down, the effect of this
is first to break the current carrying part (a) of the switch, at the same time that
this is going on energy is being stored in a spring (f) which works direct or
controls the contact rod (b) above referred to, when the handle of the switch has
got a little further and has sufficiently well broken the circuit through the heavy
current carrying parts (a) of the switch the mechanism operates a catch which
releases the spring and shoots off the contact rod. This catch is operated in the
following manner. When contact is to be broken the handle (e) and contacts (a)
are pulled over on centre (9), the link (h) pivotted at (i) being carried down with
it. This link at its other end is attached to lever (k) which is pivotted at (1) on the
fixed frame (r). Lever (k) in being pulled down compresses spring (f). While
the spring is being compressed the contact rod (b) is prevented from coming down
by, the bell crank (n) pivotted at (o). The mechanism for releasing the bell crank
is in the form of a block (n) on lever (k) which by pressing down on the nut stops
on hanging pin (p) pulls over the catch and so allows the compressed spring to pull
down the contact into the oil bath. The lower end of oil bath is made tight with
a gland and stuffing box and to deaden the jar to the apparatus, I place a dash
pot (9) beneath the spring.
The action of the spring is therefore first to separate the current carrying parts
without sparking and secondly to quickly break in air the current passing through
the remaining contact which in its turn is entirely immersed in the oil so as to
drown out any spark which may have a tendency to follow.
In some cases I may use the spring itself for carrying the lesser portion of the
current and for giving the quick break.
In some cases I may put the quick breaking gear into the oil or insulating bath
and actuate these parts by means of a reciprocating rod passing horizontally through
glands in the box.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare what I
claim is.
(1.) In electric switches providing two distinct paths for the current one of
which is of ample section and carries the bulk of the current and is first broken,
when it is desired to switch off the current the second contact then carrying all the
current until the circuit is broken and the contact of which on breaking disappears
into oil or other insulating fluid for the purpose of drowning out any are which may
be formed.
(2.) Electric switches in which the contacts are immersed in oil or other
insulating fluid upou breaking substantially as and for the purpose described.
(3.) My improvements, in electric switches substantially as described and
illustrated.
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