APPLIANCES FOR AUTOMATICALLY CONTROLLING ELECTRICAL CIRCUITS
Year: 1884

page_text: I KILLINGWORTH WILLIAM HEDGES, Civil Engineer, of N° 25 Queen Anne's Gate,
Westminster, in the County of Middlesex, do hereby declare the nature of my
Invention for APPLIANCES FOR AUTOMATICALLY CONTROLLING ELECTRICAL CIRCUITS
to be as follows:-
My invention relates to an automatic arrangement for controlling the excess
current in an electric circuit; it may be applied either where it is desirable to
substituto a spare fuse for that melted in a safety plug such as is used to protect
electric light wires or to insert a resistance or to open the circuit. In this invention
I arrange a lever in such a manner that so soon as the working current in the main
circuit increases, the lever is urged by a spring or weight into a new position so
as to make the current pass through the spare fuse or, if a spare fuse is not
employed, break the circuit. The lever is at first held by a locking arrangement
which is released by the action of an electro magnet wound with fine wire which
is so placed in a shunt circuit that a portion of the current before it either passes
through the fuse that is being used, or through the circuit in which the lamps are
placed, shall be diverted through the coils of this electro magnet. At the moment
of rupture of the fuse or when the current becomes too strong more current flows
through the coils of the electro magnet and enables it to release the locking
arrangement and thus cause the spring or weight to move the lever. This
arrangement can be employed independently of any fusible cut out as the magnet
will release the locking gear and open the circuit so as to form an automatic
contact breaker.
An artificial resistance will often have to be used to prevent an excess current
passing through the fine wire of the electro magnet, this resistance may be of any
material but I prefer carbon or a metallic resistance in a compact form which can
be mounted on the same stand as the electro magnet. The arrangement of electro
magnet and locking gear can be applied to the duplicate form of electrical safety
plug, shown by drawing, Fig. 5. accompanying the specification of my letters
patent No 719, 1883, or it can be fitted to any switch or contact breaker by
arranging a spring so that it is urged to break contact on the locking gear being
released by the action of the electro magnet. For compactness I prefer to arrange
it in combination with a special new form of switch or contact breaker which
I construct as follows:-
A flat plate of metal is furnished with a projecting piece in the form of a spring
meinst which the short end of an insulated pivotted lever having an L. shaped

page_text: projection is caused to rub at the time when electrical contact is made and when
contact is broken, and the plate is so arranged that although the main part of the
current will flow through it and the long arm of the lever, when the contact is
on, a portion of it also passes through the short arm and the projecting piece at
the time of breaking contact and after the main part of the current is broken the
projecting piece serves the double purpose of taking the spark caused by breaking
or making contact and at the same time acts as a spring to cause the contact to be
rapidly broken. The short end of the lever may be extended so as to offer a good
rubbing surface to the projecting spring piece. To prevent too much current
passing which might injure the spring action I connect the projecting end to the
metallic base by means of good conducting material. In small switches it is
possible to stamp the projecting piece out of the metal forming the base but in
larger ones it is better to mount this piece on a material having low con-
ductivity or even on an insulator and causing the circuit to be made by the
pressure of the projecting piece on to a suitable projection on the metallic base. I
prefer making the long end of the lover make a wiping contact against a pro-
jection on the metal plate which projection may be made of thin brass with slits in
it. In order to prevent the switch being left in position where an arc may be
formed I either make the contact end of the lever sufficiently heavy to fall over
by the action of gravity or I use an auxiliary spring. When used in connection
with the automatic circuit breaker the long end of the lever is furnished with an
iron projection which is so disposed that when the contact is made the iron is in
the field of the electro magnet and may be moved by the magnetic action when
the current becomes too powerful and thus tending to attract the iron towards
itself and move the lever in a radial direction which movement is. assisted by the
action of the contact spring and by gravity.

page_text: I KILLINGWORTH WILLIAM HEDGES, of N° 25 Queen Anne's Gate, Westminster,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of
my Invention for "APPLIANCES FOR AUTOMATICALLY CONTROLLING ELECTRICAL
CIRCUITS," and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My invention relates to an automatic arrangement for controlling the excess
current in an electric circuit, it might be applied either where it is desirable to
substitute a spare fuse for that melted, in a safety plug, such as is used to protect
electric light wires, or to insert a rosistance, or to open the circuit. In the
invention I arrange a lever in such a manner that so soon as the working current
in the main circuit increases, the lever is urged by a spring or weight into a new
position so as to make the current pass through the spare fuse, or if a spare fuso is
not employed break the circuit. The lever is at first held by a locking arrange-
ment which is released by the action of an electro-magnet wound with fine wire
which is so placed in a shunt circuit that a portion of the current before it either
passes through the fuse that is being used, or through the circuit in which the
lamps aro placed, shall be diverted through the coils of this electro magnet. At
the moment of rupture of the fuse or when the current becomes too strong more
current flows through the coils of the electro magnet and enables it to release the
locking arrangement and thus cause the spring or weight to move the lever.
artificial resistance will often have to be used to prevent an excess current passing
through the fine wire of the electro magnet, this resistance may be of any material
but I prefer carbon or a metallic resistance in a compact form which can be mounted
on the same stand as the electro magnet.
An
The arrangement of electro magnet and locking gear can be applied to the
duplicate form of electrical safety plug shown by drawing Fig. 5. accompanying
the specification of my letters patent N° 719, 1883. or it can be fitted to any
switch or contact breaker by arranging a spring so that it is urged to break
contact on the locking gear being released by the action of the electro magnet.
An artificial
Figs. 1. and 2. show the application of the locking gear to a duplex cut out, the
lever A being held down by a notch in the armature B against the pressure of
the spring C when the current through the magnet exceeds a certain amount
the amature will be attracted at B' and A will be released so as to take the
position A. In Fig. 11 F is the working fuse and F¹ the spare one.
resistance may be substituted for F', or the arrangement can be employed without
melting a fuse if one space of a duplex cut out is bridged over by a conductor of
such resistance to cause a sufficient portion of the current to pass through the shunt
wire of the magnet which will then release the locking gear and open the circuit
so as to form an automatic contact breaker. In order to prevent the heating of the
lever A at the contacts D. D. when the whole of the current passes through them
I prefer to turn them as shown so as to give more elasticity, when powerful
currents are used I also make use of the spring S to press the lever up to its work.
The pull on the armature B by the magnet M can be adjusted by means of a spring
or weight, also the amount of current passing through M can be varied by altering
the resistance R.

page_text: Fig. 3. shows the same arrangement applied to an ordinary switch to which is
added the arm E in order that the contact may be rapidly broken the arm E may
have a counter weight urging it into the position shown at D¹ or the switch may
contain a spring in the base as shown at Fig. 5. of my specification N° 4025-1882.
and therein described.
Fig. 4, shows the plate A extended and furnished at one end with the
armature B which when attracted by the magnet M causes the short end of the
L shaped lever D to be set free and the lever D to drop to the position shown
at D, the connection between the line I and I' is thus severed. In order to form
good contact between D and A I sometimes split A or its projecting portion C,
which is provided to take the spark on breaking contact and avoid injuring the
spring A. Where desirable instead of using the action of gravity to cause D to
drop a spring may be employed as shown in Fig. VI. Another modification of my
invention is shown in Fig. V, the lever D has a weighted iron ond E which is
attracted by the electro magnet M on the current becoming sufficiently powerful to
overcome the counter action of the knife spring F on the plate A; when the lever D
is sufficiently attracted the tendency of the spring F will be to throw over the lever
and break the circuit.
In small switches it is possible to stamp the projecting spring F out of the metal
forming the base A but in larger ones it is better to mount this piece on a material
having low conductivity or oven on an insulator and causing the circuit to be made
by the pressure of the projecting spring on to a suitable conductor united to the
metallic base.
This is shown by Fig. VI. in which the short end G of the lever D causes the
spring F to be pressed down on a subsidiary spring F1 in connection with the
terminal 1 the main contact when the switch is closed being made through A which
is insulated from the knife blade spring F.
I am aware that small electro magnets in a shunt circuit have been used for
the purpose of short circuiting a lamp when from any cause the lamp was
extinguished, and I make no claim to the use of such an electro magnet
generally.
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
1stly The application of a tripping gear worked by, an, electro magnet in a shunt
circuit of high resistance to an electrical safety plug substantially as described and
shown in figures I and II.
2ndly The apparatus described and. shown in Figure III whereby a tripping gear
worked by an electro magnet in a shunt circuit of high resistance, releases a lever
in connection with a switch which is then actuated either by a spring or a weight 4
so as to open the circuit.
3rdly The apparatus shown in Figures IV. V. and VI, which if desired may be
worked automatically by means of an electro magnet in a shunt circuit of high.
resistance, in which apparatus the short arm of the lever makes a good rubbing
contact with a spring and by being operated upon by the spring assists to make or 4
break the main contact more quickly.
D1001
NAAK
GEO. DOWNING,
Agent for Applicant.