Year: 1887

page_text: Date of Application, 29th Apr., 1887
Complete Left, 30th Jan., 1888.
Complete Accepted, 9th Mar., 1888
We, ARTHUR CECIL COCKBURN, of 26, Petherton Road, Canonbury, London, in
the County of Middlesex, Electrical Engineer, and EUSTACE THOMAS, of Albany
House, Prince of Wales' Road, Battersea, in the County of Surrey, Electrician, do
hereby declare the nature of this invention to be as follows:-
Our invention relates to improvements in switches, or apparatus used to control an
electric circuit. In the usual form of switch the contact pieces are forced into contact
catches, and are maintained there merely by friction, or by a spring, and are not locked
in position.
And the object of our improvement, is to ensure a safely locked connection, com-
bined with a quick break of contact at the moment of breaking circuit, thereby
lessening the spark.
In our improved locking switch this difficulty is overcome by providing a latch, or
other locking device, which, when contact has been established, springs into action,
and holds the movable contact piece, or bar, firmly in position, independent of the
handle or button, and independent of the pressure or friction of the fixed contact
pieces, and we find that this device is much more reliable than devices dependent on
the friction or pressure of the fixed contact or contact pieces, inasmuch as the contact
surfaces wear with use, and their elasticity, and their grip alter with time.
When the handle or button is turned in the opposite direction, in the course of its
movement it causes the latch to be withdrawn, the contact piece or bar being free to
move independent of the handle or button, and being actuated by a spring, flies quickly
back so soon as the latch is withdrawn, and thus breaks the electric circuit with great
certainty and rapidity. The contact bar or piece must have as little friction as possible
on its working parts. The bar or piece is not moved at all out of full contact with
the fixed contact or contact pieces, until the latch or locking device is withdrawn, and
then the spring exerts its full power, and drives the movable contact bar or contact
piece from between the fixed contact or from off the fixed contact surface or surfaces.
The handle, in breaking contact, performs no action on the movable bar, but merely
noves round until, as it approaches the "off" position, its last action is to actuate the

page_text: unlocking mechanism, and so leave the bar free to fly round under the unimpeded
action of the spring. The fixed contact or contact pieces are arranged so as to allow
the movable contact piece or bar as much free motion as possible consistent with good
electrical contact; and the spring is made strong enough to move the bar from between
them or from off them, so that at the moment when the movable bar contact is just
passing out from between their ends, it shall have attained a fair speed under the
spring's action. We may employ one or more springs, or a weight or other equivalent
means as case may require.
The abovo device is applicable not only to simple switches, but also to double and
multiple switches which break one, two or more circuits at two or more points
simultaneously. The contact parts being duplicated or triplicated or the like, as
required. It is also applicable to double-pole switches, in which ono movement of the
band canses a simultaneous breaking of two circuits, or of the two parallel mains of a
distribuating system, the contact parts in such case being duplicated but insulated
from one another in an appropriate manner.
Dated this Twenty-aighth day of Annil 1007
ARTHUR C. COCKBURN.
EUSTACE THOMAS.

page_text: We, ARTHUR CECIL COCKBURN of 26 Petherton Road, Canonbury, London, in the
County of Middlesex, Electrical Engineer, and EUSTACE THOMAS of Albany House,
Prince of Wales' Road, Battersea in the County of Surrey, Electrician, do hereby
declare the naturo 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 relates to "switches" or apparatus employed for maintaining or
interrupting the continuity of an electric circuit the object being to ensure perfect
contact of the circuit closing pieces when the current is required and to effect a more
instantaneous separation of the pieces than can be effected by hand alone when it is
desired to interrupt or shut off the current; this sudden separation being necessary
to preserve the contact pieces from the destructive action of the spark or electric are
which is formed at the moment of breaking contact between two conductors.
The invention will be more readily understood by reference to the accompanying
drawings in which
Fig. 1 represents a plan of the switch locked in position to allow the current to
pass, the handle being removed to afford a better view of the locking mechanism.
Fig. 2 is a similar plan showing the position of the parts just as contact is about to
be broken and
Fig. 3 a plan showing the position after contact has been broken..
Fig. 4 is a sectional elevation, the parts being shown locked as in figure 1, and
Fig. 5 is a sectional elevation showing position after breaking contact.
Figs. 6, and 8 are details of detached parts which will be readily recognized, by
their letters of reference.
A is a base block formed of any suitable insulating material and on the face of this
block are fixed the terminals B.. The interior of the block is recessed to receive a
plate C (which may however be dispensed with and the parts attached thereto secured
to the material of the block) in the centre of which is a boss C₁ through which passes
a spindle D the spindle being secured on the underside of the plate by nut D¹.
Fitting loosely on the spindle is a switch arm E to which is connected a short arm E¹
bent downwards, the end e thereof being adapted to engage with a spring F which is
rivetted to the plate C, the free end standing up some distance from the plate as shown
in figures 4 and 5 and in detail figure 6. An arm G is fixed to the spindle D, the
end of which is bent downwards so that when the spindle is turned by means of the
handle D2 the end of the arm G will come in contact with the switch arm E and cause
the latter to partake of its motion. The switch arm is under the influence of a spiral
spring H one end of which is attached to a pin h on the underside of the arm E¹ (see
fig. 8 which is cross section of switch arm) and the other end to a pin h¹ on the
plate C (see fig. 6). The tendency of this spring is to draw the switch arm away from

page_text: the terminals B to the position shown in figure 3 in which the ends of the arm are as
far removed from the terminals as possible.
To make contact the operator turns the handle D' and the arm G thereon coming in
contact with the switch arm E turns it in the direction of the arrow in figure 3, until
the ends of the arm rest upon the contact plates B as shown in figures 1 and 2. During
this operation the spring H is wound up and would on the release of the handle draw
back the switch arm to its original position if not prevented by the end e of the arm E¹
coming in contact with the raised end of the spring F which from the direction of its
incline allows the arm E¹ to pass freely over it during the circuit closing motion but
opposes its return; thus the circuit once completed will remain so until purposely
broken.
To effect this the operator turns the handle D2 in the direction opposite to the arrow
in figure 3 and the handle will turn without producing any result until the arm G
reaches the spring F. The end g of this arm is so inclined as to depress the end of
the spring F on coming in contact therewith and by so doing it releases the end of the
arm E' from the spring F. The latter being released the spring H comes into play
and causes the switch arm E to quickly revolve until stopped by coming in contact
with the vertical edge of the arm G where it remains as shown in figure 3. The
operation of the spring being incomparably more sudden than any motion of the hand
no time is allowed for the formation of a destructive arc as the ends of the switch
arm E pass off the ends of the terminals B.
It will be observed that the incline on the side of the turned down portion g of
the arm G is not continued to the bottom the extreme end being vertical to prevent
the arm from depressing the spring F too much and passing over it. The spring F
may if desired be fixed to the side a of the recess in the base A and the projections E
and G modified to suit.
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. In a switch or circuit closer such as described the combination with a spring
actuated switch arm such as E spring F and stop E' for retaining E in the contact
position of a trigger or projection such as G for releasing stop E' and arresting motion
of the switch arin substantially as described and illustrated in the accompanying
drawings.
2. The complete switch lock substantially as and for the purpose described and
illustrated in the accompanying drawings.
Dated this 28th day of January 1888.
ARTHUR C. COCKBURN.
EUSTACE THOMAS.