A New or Improved Method of Making and Breaking Electric Circuits, and Apparatus therefor.
Year: 1891

page_text: Date of Application, 29th Dec., 1891
Complete Specification Left, 16th Sept., 1892-Accepted, 22nd Oct., 1892
PROVISIONAL SPECIFICATION.
A New or Improved Method of Making and Breaking Electric
Circuits, and Apparatus therefor.
We, WILLIAM HENRY DINGLE, of 13 Hindon Street, London, S.W., and
JOHN MACKENZIE URQUHART, of 10 Denbigh Street, London, S. W., Electrical
Engineers, do hereby declare the nature of this invention to be as follows :-
:-
This invention relates to a new or improved method of making and breaking
electric circuits, and apparatus therefor, by which certain advantages are obtained.
We employ two contact pieces (frequently duplicated) as is usual in electric
switches, one of which, namely the one which is .xed as a rule to the base of the
switch, we shall hereinafter refer to as the "base piece," and the other, namely
that which is moved to make and break contact with the base piece, we shall
hereinafter term the "rocking lever" for the reason that it is, in our invention,
made in the form of a rocking lever or lever of the first order. One end of the
said rocking lever is caused to come into contact with the base piece for the purpose
of making or closing the electric circuit; and this end we shall hereinafter call the
active end, whilst we shall term the other end the free end. To the active end of
the rocking lever (or to a part of the rocking lever between its fulcrum and the
active end) we attach a push piece or plunger (hereinafter termed the "making"
plunger) which when depressed depresses the active end of the rocking lever into
contact with the base piece, so as to make or close the electric circuit, whilst at the
same time the free end of the rocking lever is raised. Over this free end (or
between it and the fulcrum) is placed a spring which as the said free end is raised
is deflected or put under tension so that it will tend to depress the said free end
and so raise the active end out of contact with the base piece to break the circuit.
This however it is prevented from doing by a detent lever which engages a notch
or projection or the like on or connected to the rocking lever. The said detent
lever is maintained in engagement with the said notch or projection by a spring.
To differentiate these two springs we shall term that just mentioned the detent
spring and that previously mentioned we shall term the rocking lever spring. A
second push or plunger, which for distinction we shall term the "breaking'
plunger, acts upon this detent lever so as when depressed to release it from the
notch or projection on the rocking lever and at the same time to deflect or put
tension upon the detent spring. The said detent spring is now maintained in its
deflected state, that is to say in a state of tension, by the rocking lever spring
acting say through the rocking lever and detent lever.
"
The action of our invention can now be understood. Let us assume that the
circuit is normally open and that we wish to make or close it. To do so we press
down the making plunger until the active end of the rocking lever is in contact
with the base piece. This movement will raise the free end of the rocking lever,
deflect or put tension on the rocking lever spring, remove the notch or projection
of the rocking lever from the detent lever and so release the detent spring, so that
the latter will cause the detent lever to engage the notch or projection upon the
rocking lever so as to retain it in its new position and at the same time raise the
breaking plunger. The circuit is now made or closed and the parts are locked in
this position, the making plunger being depressed and the breaking plunger
elevated. Let us now assume that we wish to break the circuit or open it. To do
so we press down the breaking plunger. This movement will deflect or put tension
on the detent spring, disengage the detent lever from the notch or projection of the
rocking lever and so release the rocking lever spring so that the latter will force

page_text: down the free end of the rocking lever, and so suddenly force the active end away
from the base piece, thus quickly breaking or opening the circuit, and at the same
time causing the notch or projection of the rocking piece to engage the detent lever
and thus retain the parts in position, the making plunger being elevated and the
breaking plunger being depressed. The parts are now in their normal position
again ready when required to go through the same cycle of operations again.
It will be seen that at any time only that plunger which is the one which
requires to be actuated is elevated or in a position to be actuated. This fact and
the quick action of the springs prevents any mistake in handling. It will also be
noticed that just as the detent lever retains the rocking lever in position against
the action of the rocking lever spring when the parts are in one position, so the
rocking lever serves to retain the detent lever in position against the action of the
detent lever spring when the parts are in the other position.
We have hereinbefore spoken of two springs, the rocking lever spring and the
détent spring. In practice we generally find it convenient to substitute a single
double acting spring for these two separate springs. A convenient form of
double acting spring for our purpose is one of V shape. It will be seen that if
such a spring be fixed at its angle, or part where the two limbs meet, the said two
limbs will act in opposite directions so that the one limb may serve as the rocking
lever spring and the other limb as the detent spring.
Instead of actuating the two plungers by hand we sometimes find it convenient,
especially in the case of switches for large currents, to attach a lever handle to
our apparatus which according as it is moved in one direction or the other will
depress one or other of the plungers.
It will be observed that the action of the rocking lever spring is such as to
ensure a quick break from full load, as it is termed, so that sparking at the contact
surfaces is reduced to a minimum.
Dated th: 00L
D
1
1001
W. H. DINGLE,
J. M. URQUHART,
Per J. G. Lorrain, M. Inst. E.E., M. Inst. M.E., &c.,
Norfolk House, Norfolk Street, London, W.C.,
Applicants' Patent Agent.
COMPLETE SPECIFICATION.
A New or Improved Method of Making and Breaking Electric
Circuits, and Apparatus therefor.
We, WILLIAM HENRY DINGLE, of 13 Hindon Street, London, S.W., and
JOHN MACKENZIE URQUHART, of 10 Denbigh Street, London, S. W., Electrical
Engineers, 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 :-
We employ two contact pieces (frequently duplicated) as is usual in electric
switches, one of which, namely the one which is fixed as a rule to the base of
the switch, we shall hereinafter refer to as the "base piece" and the other, namely.
that which is moved to make and break contact with the base piece, we shall
hereinafter term the "rocking lever" for the reason that it is in our invention made
in the form of a rocking lever or lever of the first order. One end of the said
rocking lever is caused to come into contact with the base piece for the purpose of
making or closing the electric circuit; and this end we shall hereinafter call the
"active end" whilst we shall term the other end the "free end." To the active
end of the rocking lever (or to a part of the rocking lever between its fulcrum and
the active end) we attach a push piece or plunger (hereinafter termed the "making'
plunger) which when depressed depresses the active end of the rocking lever into
"

page_text: contact with the base piece, so as to make or close the electric circuit, whilst at the
same time the free end of the rocking lever is raised. Over this free end (or
between it and the fulcrum) is placed a spring which, as the said free end is raised,
is deflected or put under tension so that it will tend to depress the said free end, and so
raise the active end out of contact so as to break the circuit. This however it is
prevented from doing by a detent lever which engages a notch or projection or the
like on or connected to the rocking lever. The said detent lever is maintained in
engagement with the said notch or projection by a spring. To differentiate these
two springs we shall term that just mentioned the detent spring and that previously
mentioned we shall term the rocking lever spring. A second push or plunger,
which for distinction we shall term the "breaking" plunger, acts upon this detent
lever so as when depressed to release it from the notch or projection on the rocking
lever, and at the same time to deflect or otherwise put tension upon the detent
spring. The said detent spring is now maintained in its deflected state, that is to
Bay in a state of tension, by the rocking lever spring acting say through the rocking
lever and detent lever.
We have herein before spoken of two springs, the rocking lever spring and the
detent spring. In practice we generally find it convenient to substitute a single
double acting spring for these two separate springs. A convenient form of double
acting spring for our purpose is one of V shape. It will be seen that if such a
spring be fixed at its angle or part where the two limbs meet, the said two limbs
will act in opposite directions so that the one limb may serve as the rocking lever
spring and the other limb as the detent spring.
Having now described our invention in general terms so as to define its scope, we
shall proceed, in order to show clearly how it is to be or may be carried into effect,
to describe in detail, and by way of a type or example, a switch in which the
various features of our invention are embodied. In order that this example may
be more fully and readily understood we append hereto two sheets of drawings
illustrating the said switch, which is in fact that form of our invention which we
have hitherto found to give the best results in practice.
In these drawings
Figure 1 is a side elevation showing the parts in the positions which they occupy
when the circuit is open or broken; and
Figure 2 is a longitudinal section showing the parts in the position which they
occupy when the circuit is made or closed.
!
Figure 3 is an end elevation and Figure 4 a plan.
Figure 5 is designed to show how a lever handle may be adapted to actuate the
'switch as hereinafter to be mentioned.
In all these figures the switch is shown with the cover removed.
Figures 6, 64, 7, 7 and 8 are details.
A is the base of the switch formed of slate, wood or other suitable material upon
which is mounted the base piece B, in this case consisting of two separate pieces of
sheet brass bb bent at right angles as shown. These two pieces are fixed to the
base by the screws 6' which may also serve for the attachment of the wires in the
usual way. C is the rocking lever (shown separately in plan in Figure 6 and in
section in Figure 6) in this case consisting of two stampings cc of sheet brass
soldered to and united by the metal piece c¹. This construction of rocking lever
provides the necessary elasticity at the active end to ensure good contact with
the base piece. is a pin constituting the fulcrum on which Crocks. D is the
making plunger articulated to C by the pin d. c is the free end of C. E is a
double acting V shaped spring attached at its angle to the pin g by being taken two or
three turns round the same. The limb e of the said spring serves as the rocking
lever spring and the limb e as the detent spring. In the case illustrated instead of
having such a double acting V spring on each side of the switch we use a single
piece of spring wire as shown in the figures where it will be noticed that this
arrangement is equivalent to two separate V shaped springs joined at the part.
G is the detent lever turning on the pin g hereinbefore mentioned. G is shown

page_text: separately in plan in Figure 7 and in elevation in Figure 7. g is the part which
engages in the notch c' of C and is the arm on which the detent spring (in this
case limb e¹) acts by pressing on the pin g. This pin g³ also serves to articulate
the breaking plunger H to the said army of the detent lever.
The action is as follows. Let us assume that the circuit is normally open and
that we wish to make or close it. We do so by the following method, the parts
being in the position shown in Figure 1. We press down the making plunger D
until the active end of the rocking lever C is in contact with the base piece B,
that is to say until the active ends of the pieces cc are between the pieces b b.
The circuit is now completed between the screws b¹ and the current can pass.
At the same time this movement has raised the free end c* of the rocking lever C,
deflected or put tension on the rocking lever spring e, removed the notch c from
the part g' of the detent lever G and so allowed the detent spring el to cause the
part g' of the detent lever G to engage notch e in its new position and at the same
time raise the breaking plunger. The parts are now locked in the position shown in
Figure 2.
Let us now assume that we wish to break or open the circuit. We do
.this by the following method. We press down the breaking plunger H. This
.movement will deflect or put tension on the detent spring e¹, disengage part g¹ of
the detent lever G from the notch c and so release the rocking lever spring e so
that the latter will force down the free end of the rocking lever C and thus
suddenly force the active end of C away from the base piece B, thus quickly
breaking or opening the circuit and at the same time causing the notch of C to
engage the part gl of G and lock the parts in the position shown in Figure 1
again.
It will be seen that at any time only that plunger which is the one which
requires to be actuated is elevated or in a position to be actuated. This fact and
the quick action of the springs prevents any mistake in handling. It will also be
noticed that just as the deteut lever retains the rocking lever in position against
the action of the rocking lever spring when the parts are in one position, so the
rocking lever serves to retain the detent lever in position against the action of the
detent lever spring when the parts are in the other position.
Instead of actuating the two plungers by hand we sometimes find it convenient,
especially in the case of switches for large currents, to attach a lever handle to our
apparatus which according as it is moved in one direction or the other will depress
one or other of the plungers. A switch so provided with a handle is shown in
Figure 5. In this switch X is the handle pivotted on the bracket or fork Y which
is screwed to the top plate ; of the frame J. As the end of this handle is raised
or lowered it will be seen that one or other of the two plungers is actuated so as to
make or break the circuit. When Y is unscrewed from the top plate the handle
is removed and we have au ordinary switch as shown in Figures 1 to 4.
:
Instead of employing a replaceable handle of this kind we generally use for large
currents a switch with a handle permanently attached and in that case we prefer
a handle in the form of an inverted T as shown in Figure 8. In this figure it will
be seen that the links D¹ and H₁ correspond with the plungers D and H of
Figures 1 to 5 and.that circuit is made or broken according as the handle is moved
to one side or another.
It will be seen that the action of the rocking lever spring is such as to ensure a
quick break, as it is called, so that sparking at the contact surfaces is reduced to a
minimum.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. The new or improved method of making electric circuits substantially as set
forth.
2. The new or improved method of breaking electric circuits substantially as set 5
Sl

page_text: 3. The new or improved apparatus for making and breaking electric circuits
consisting of the combination of a making plunger, a rocking lever, a detent lever ;
a breaking plunger and a spring or springs serving to actuate the said rocking and
detent levers, the whole acting substantially as and for the purpose specified.
Dated this 16th day of September 1892.
J. G. LORRAIN, M. Inst. E.E., M. Inst. M.E.,
Norfolk House, Norfolk Street, Strand, London, W.C.,
Chartered Patent Agent.