IMPROVEMENTS IN ELECTRICAL SWITCHES
Year: 1885

page_text: I, SEBASTIAN ZIANI DE FERRANTI of 5 Stanwick Road, West Kensington in
the County of Middlesex Electrician do hereby declare the nature of my inven-
tion for "IMPROVEMENTS IN ELECTRICAL SWITCHES" to be as follows:-
According to this invention I make electrical switches in such a manner that by
the first movement of their knob or handle (which has to be turned or moved to
make or break a circuit) energy is caused to be stored up in a spring or springs
without affecting the contacts until the springs have been brought into such a state
of tension or compression that they overpower the resistance which retained them
and that they then fly or cause other parts to fly quickly into position to make or
to break a circuit as the case may be-One way in which this may conveniently
be effected is as follows:-
:-
Two spirally curved spring arms are secured to an axis one extending out from
it on one side and the other from the opposite side.
At each side of the axis are fixed three metallic pegs at such a distance from the
axis that the outer ends of the spring arms strike against them if the axis is turned
and a curve or bend is formed at the outer end of each spring arm to fit against the
sides of whichever metallic peg it may be brought against. Whenever the curve
or bend at the outer end of the spring arms so fits against two of the pegs the outer
ends of the spring arms are thereby retained and cannot be moved past these pegs
until by turning the axis a considerable strain is put upon the spring arms, these
arms then yield and fly against and are arrested by the next pegs and so on. The
central peg of the three pegs at each side of the axis is coupled to one of the con-
ducting wires.
The other pegs simply serve as stops and are not coupled to the
conducting wires.
When the ends of the springs are bearing against two of these
latter pegs no current passes. If a partial turn is then given to the axis it tends
first to wind up the springs around itself until the springs become so bent that
their ends slip off from the pegs which were retaining them and fly against and
are retained by the two central pegs thereby instantaneously completing the circuit.
A further turn agains breaks the circuit and so on.
For switches for controlling the passage of stronger currents than switches such
as above described are adapted for if used alone I in injunction with such electrical
switches (or it might be in conjunction with other forms of electrical switch in
which a metallic bridge piece is used to make contact with terminal pieces at the
TD 07

page_text: ends of two conducting wires) use a shunt circuit through which the current has to
pass whenever the metallic bridge piece is moved into such a position that it is no
longer in contact with the metallic terminals and this shunt circuit I make to pass
through a liquid such for example as water and provide means for gradually
arresting the passage of the current through the liquid and so completely breaking
the circuit.
One way of effecting this is to connect one end of the conductor to a terminal
plate contained within an inverted porous cell immersed in the water whilst the
other is attached to a plate secured to the outside of the cell so that when the
current passes through the shunt circuit water is decomposed and one of the gases
thereby liberated collects in the inverted cell and gradually expels water from it
until the water has been forced down to a level below the bottom of the terminal
plate contained within it when the passage of the current is completely arrested;
or in place of causing the passage of the current to be arrested gradually in the
above manner I effect the same object by causing the current in the shunt circuit
to pass from one metallic plate immersed in the liquid to another plate and by
causing the turning or moving of the switch handle to gradually withdraw one of
these plates from the liquid after the metallic bridge piece has been moved out
of the way.
For obtaining a compact switch with a large surface I prefer to use
several places, both moveable and fixed in the liquid. By these means all possi-
bility of the metallic bridge piece being destroyed by the passage of sparks at the
time of breaking or making the circuit is completely avoided.

page_text: Improvements in Electrical Switches.
I, SEBASTIAN ZIANI DE FERRANTI of 5 Stanwick Road, West Kensington in
the County of Middlesex Electrician do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
According to this invention I make electrical switches in such a manner that
by the first movement of their knob or handle (which has to be turned or moved
to make or break a circuit) energy is caused to be stored up in a spring or springs
without affecting the contacts until the springs have been brought into such a state
of tension or compression that they overpower the resistance which retained them
and that they then fly or cause other parts to fly quickly into position to make or
to break a circuit as the case may be.
For switches for controlling the passage of stronger currents I use a shunt circuit
through which the current has to pass whenever the metallic bridge piece is moved
into such a position that it is no longer in contact with the metallic terminals and
this shunt circuit I make to pass through a liquid, such for example as water and
provide means for gradually arresting the passage of the current through the liquid
and so completely breaking the circuit.
In order that my said invention may be most fully understood and readily
carried into effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of an electrical switch constructed in accordance
with my invention.
Figure 2 is an horizontal section of the same.
Figure 3 is a section on the line 1, 1, in Figure 2.
a a is the case of the instrument, it is made in two parts held together by screws
so that the electrical connections may be readily accessible.
The upper part of the case carries an axis b provided with a handle b¹ and
terminating in a disc b². c is a central stem securely fixed mechanically to the
axis but insulated from it electrically. The stem c carries two spring blades d, d,
these constitute a spring bridge piece rigidly connected with the handle. As repre-
sented in the drawing these blades are double, the outer face of each is of copper
and the copper strip is supported by a blade of spring steel. e e are metallic pegs
insulated electrically from the case but mechanically fixed to it-these form the
extremities of the two conductors which are to be electrically connected and
disconnected by the switch.
The cavities in the case beyond the pegs e e are to accommodate the joint in the
insulating material around the line conductor.
is
ff are other pegs carried by the case, these have no electrical connections.
a pawl carried by the case and intended to engage with notches 62x in the periphery
of the disc b³.
The action of the apparatus is as follows:-when the parts are in the position
in which they are represented in the drawing with the spring blades d d. resting

page_text: against the pegs e e and with concavities at the ends of the spring blades engaging
with corresponding convexities at the extremities of the pegs, the current passes
freely in the circuit through the spring blades. When the handle b¹ is turned in
the direction in which the pawl g permits it to turn the first effect is to further
deflect the spring blades dd; then afterwards the blades escape from the pegs and
very rapidly spring away from them. There is consequently much less sparking in
opening the circuit than there would be if the passage of the blades d d were to
take place comparatively slowly and with no greater rapidity than that due to the
movement of the handle.
The pawl g prevents any back turning of the axis-the spring blades can only
close the circuit again when required by first being brought up against the pegs ff.
Against these pegs the movement of the handle causes the springs to be compressed
until the concavities at the ends of the springs come to embrace the pegs ff just as
in Figure 2 they are shown embracing the convex ends of the pegs e. A further
compression of the springs then ensues until presently they escape and pass
suddenly from the pegs ff to the pegs e e thereby closing the circuit with the
same rapidity with which it was previously opened.
In place of using a pawl g to prevent the movement of the parts in the reverse
direction, a like result may be arrived at by providing other pegs ff to receive the
ends of the spring blades & when they leave the pegs c. e.
Figure 4 is an horizontal section and Figure 5 is a front elevation of a switch
suitable for operating with strong currents. It consists of a box of insulating and
impermeable material which when the apparatus is in use contains water.
The front of this box has a bearing in the centre through which an axis i
passes. On the axis within the box a boss is fixed, it carries a number of semi-
circular blades which in one position of the axis dip down into the water
which the box contains.
The water level is below the boss and by turning the axis the blades can be
made to entirely emerge. There are also other metallic blades jj fixed within the
lower part of the box which always remain immersed in the water.
Outside the box the axis carries a handle 2 by which it is turned to open and
close the circuit: this handle is not shown in Figure 5. Also the axis i carries a
series of contact springs 1 and 2; these springs are represented in Figure 4 in
contact with pieces of metal and inlaid in the front of the box and to these
pieces the binding posts m³, m² are attached. These binding posts receive the
circuit conductors. The piece 2 on which the longer springs bear is connected
permanently with the metallic blades j within the box; its face is of the same
width as the springs and as soon as the axis is moved from the position in which it
is shown in the figures the springs commence to pass off the piece 72 and on to the
track n which is of metal insulated from and having no electrical connections.
The piece on which the shorter springs bear is of such dimensions that the
springs remain upon it until the operation of the switch which requires a half turn
of the axis or more is nearly completed and then the shorter springs pass on to the
track o which is insulated, and has no electrical connections.
When the parts are in the positions indicated the current passes freely through
the apparatus by the springs k². On turning the handle 2 contact with the
piece is broken but the circuit is still closed from the post m¹ to the axis i by
the springs thence to the blades i¹ and through the water to the other blades j
which are connected with the post m²-A further movement lifts the blades ¹
from the water and also causes the shorter springs ¹ to pass off the piece l' onto
the track o which is without electrical connections. On reversing the movement of
the handle the circuit is first completed through the water and afterwards by
metallic connection when the parts resume the positions in which they. are
represented in the drawings. Or if the movement of the handle is continued in
the same direction the circuit is completed again without the intervention of the
blades and . The liability to injurious sparking is much less in closing the
circuit than it is in opening,

page_text: Figure 6 13 an horizontal section of a switch in which both features of my
invention are applied.
Figure 7 is a vertical section of the same. Figures 8, 9, 10 and 11 show some of
the parts separately.
p is the case of the instrument-q², q², are sockets which are fixed to the case
but electrically insulated from it and from each other; they receive the ends of the
circuit conductors.
are contact springs attached to these sockets. 8 is a drum containing water
it is provided with a hollow pivot s¹ which is received into a socket 'fixed to the
The drum turns about this pivot.
case.
On the end of the drum strips are provided for the extremities of the springs l
and to bear upon. The strips and tare in electrical contact with the body of
the drum and allow the current to pass freely. The strips u¹ and u³ are of
insulating material. There is also a metallic strip v which although insulated from
the drum is electrically connected with blades within the drum. These strips all
appear in Figure 11 which is an end view of the drum or rather it shows the end
of the drum as it would be seen in a mirror; it is so shown for more convenient
comparison with the Figures 6 and 7.
8*8* are blades fixed within the drum and in electrical connection with it-
ww are other blades within the drum, but electrically insulated from it although
in metallic connection the one with the other and with the strip by means of.the
posts to and connecting screws. In one position of the drum all these blades 8*
and ware beneath the water and when from this position the drum is turned half
round the blades are lifted entirely clear of the liquid.
x is an axis which the case carries, it has on it a handle ¹ and a disc x². On the
edge of the disc are ratchet teeth and a pawl ³ engages with these. teeth to
prevent the handle turning in the wrong direction, a few teeth only will be
required. is another disc fixed to the drum although insulated froin it; this
disc turns freely on the axis and it has on its periphery a single tooth y¹. z is a
rocking frame with two teeth ¹ z¹ which alternately engage with the tooth y¹ and
prevent the disc turning. The rocking frame z has two inclined projections upon
it and the disc has one such projection * and when the disc is turned
these projections come into contact in such manner that the rocking frame is
moved so as to disengage the teeth y and z'. Finally the disc x³ is connected
with the disc y by a coiled spring X.
The action of the apparatus is as follows:-On turning the handle x¹ the
spring X at first becomes more closely coiled the disc a moving but the disc y
remaining stationary; presently the parts arrive at the position which the drawings
indicate the projection xx coming into contact with the projection 2².
The rocking frame z is moved, its tooth g¹ is withdrawn from the tooth y¹ and
the disc y together with the drum rapidly revolves under the influence of the
spring until the other tooth of the rocking frame stops the movement when the
drum has made half a turn. During this half turn the sequence of events has
been as follows,―
The contact spring 1 first passes to the contact surface v which it reaches before
leaving the surface t¹. The current now has an alternative course open to it through
the water in the drum to the drum case a and thence by the spring r² to the
circuit conductor connected at 92. is a valve at the pivot to give vent to any gas
which may be liberated. A further movement severs the electrical connection
between the spring and the drum; next the blades gradually emerge from the
water thereby completely arresting the current and finally the springs and 703
pass on to the insulated or insulating surfaces u¹². The next half turn given to
the handle similarly operates first to wind the spring and then to liberate the
drum and allow it to move rapidly under the influence of the spring for a half
revolution: the contact springs 7 and 2 towards the end of this movement pass
from the surfaces u¹ and u² on to the conducting surfaces t¹ and # and so the
circuit is again closed.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
(1.) An electric switch consisting of a handle a spring bridge piece fixed to the
handle and contact pegs: the whole so arranged that the continuous movement of
the handle stores up energy in the spring bridge piece and afterwards liberates it
thereby producing a rapid separation or approach of the contact parts.
(2.) An electrical switch so arranged that a shunt circuit is provided for the
current through plates or surfaces which when the main circuit is opened are
immersed but which afterwards cease to be in contact with the liquid so that the
shunt circuit may also be opened.
(3.) An electrical switch in which there is a main circuit and also a shunt
circuit, the latter by plates or surfaces immersed in liquid and in which the move-
ment of a bandle in opening the switch winds or stores up energy in a spring and
afterwards liberates the spring which then rapidly operates first to open the main
metallic circuit and afterwards to withdraw the plates or surfaces from contact
with liquid.
(4.) An electrical switch substantially as herein described.