Year: 1888

page_text: Date of Application, 29th June, 1888
Complete Specification Left, 29th Mar., 1889
Complete Specification Accepted, 4th May, 1889
We FREDERICK LAWRENCE RAWSON of No. 11 Queen Victoria Street London E.C.
Electrical Engineer, and WILLIAM WHITE of No. 11 Queen Victoria Street London
E.C. Instrument Maker do hereby declare the nature of this invention to be as
follows:-
Our invention relates to improvements in Instruments such as those used for
breaking electrical circuits whereby greater simplicity and cheapness of construction
are attained.
23
When applied to "Cut outs we wind a coil of wire upon a tube and mount this
between pivots whose axis is at about the middle of the coil and in a direction at right
angles to the magnetic axis of the coil so that the whole coil is free to rotate on the pivots
in a plane parallel to its magnetic axis. The free ends of the coil or connection pieces
attached to them are carried out at one end of the coil and arranged to dip into two
mercury cups forming the terminals of the instrument and thus the coil is included in
and completes the electrical circuit in which the instrument is placed. A moveable core
is placed inside the tube and may be of any suitable shape, but we prefer to use a soft
iron ball. When the instrument is in its working position with the coil ends in the
mercury cups this iron ball rests against a stop for which we may use a soft iron
screw placed at the end of the tube next the mercury cups, and to keep it normally in
this position the axis of the coil and tube is inclined downwards somewhat towards
this end. When the current passing through the coil exceeds a determined amount
the iron ball is drawn up into the coil by the attraction exerted upon it by the current
in the coil which overcomes the effect of gravity and the magnetic attraction of the
iron stop screw the lower end of the tube and coil is thus relieved of the weight of
the iron ball and the system being suitably balanced this end rises lifting the coil and
connections out of the mercury cups and so breaking the circuit. The coil system
turns sufficiently on its pivots as the circuit is broken to leave the axis of the tube
inclined in the opposite direction to what it was before so that there is no tendency

page_text: for the iron core to return to its former position. To increase the magnetic pull of
the solenoid upon the moveable core a short fixed iron core is sometimes fitted in the
and of the solenoid further from the mercury cups. The instrument is reset to
complete the circuit by turning the coil system on its pivots until the end connections
are fully in the mercury cups when the moveable core will fall into its position by the
action of gravity or my he pushed down by a plunger provided for that purpose.
The value of the current at which tho Cut-out may be varied between certain limits
by adjusting the stop screw which determines the norinal position of the moveable
core, or by altering the angle at which the coil system rests.
We may construct the instrument so that the current to be broken is independent
of that on the solenoid. For instance the solenoid may be wound with fine wire of
high resistance and be connected across from the positive to the negative mains while
the mercury cups at which the break takes place may be in the main circuit so that
the instrument acts as an Electro Motive Force Cutout.
This invention is also applicablo to other instruments such as a switch to be
operated from a distance and when so applied the switch arm is held in position by
means of a small roller, which projects through the contact plate so that the switch
arm can pass freely over, but cannot pass back until the roller has been lowered or
removed. This roller is held in a fork and the fork is loosely pivoted and held in
position by means of a suitable spring. We attach to the switch base a suitably pro-
portioned coil having an armature such as described, and having at its upper end a
loose pin or striker so placed or fixed that when a predetermined current is passed
through the coil the armature is rapidly drawn up and strikes the loose pin or
strikes against the fork so as to depress the roller and so allow the switch arm to
leave the contact and break the circuit. We may also use the device as a cut-out
where the use of mercury cups is undesirable, and in such case we connect the free
ends of a suitable coil with the contact plate of the switch and one main lead.
We may also apply the same to Indicators such as for telephone and telegraph
communicators and where so used we use the coil fixed as above described and pivot
flag or label so that when the armature is attracted as before described the loose pin is
made to drive the flag away from the sight-this is afterwards replaced in the usual
manner.

page_text: magnetic Attraction.
We FREDERIOK LAWRENCE RAWSON of No. 11 Queen Victoria Street, London E.C.
Electrical Engineer and WILLIAM WHITE of No. 11 Queen Victoria Street, London
E.. Instrument Maker, 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 :—
Our invention relates to improvements in Instruments such as those used for
breaking electrical circuits.
When applied to Cut Outs we wind a coil of wire upon a tube and mount this
between pivots whose axis is at about the middle of the coil and in a direction at right
angles to the magnetic axis of the coil so that the whole coil is free to rotate on
the pivots in a plane parallel to its magnetic axis. The free ends of the coil or
connection pieces attached to them are carried out at one end of the coil and
arranged to dip into two mercury cups forming the terminals of the Instrument
and thus the coil is included in and completes the electrical circuit in which the
Instrument is placed. A movable core is placed inside the tube and may be of any
suitable shape but we prefer to use a soft iron ball. When the Instrument is in its
working position with the coil ends in the mercury cups this iron ball rests against a
stop for which we may use a soft iron or other screw placed at the end of the tube
next the mercury cups and to keep it normally in this position the axis of the coil and
tube is inclined downwards somewhat towards this end. When the current passing
through the coil exceeds a determined amount the iron ball is drawn up into the coil
by the attraction exerted upon it by the current in the coil which overcomes the
effect of gravity and the magnetic attraction of the iron stop screw where iron is
used the lower end of the tube and coil is thus relieved of the weight of the iron
ball and the system being suitably balanced this end rises lifting the coil end con-
nections out of the mercury cups and so breaking the circuit. The coil system turns
sufficiently on its pivots as the circuit is broken to leave the axis of the tube inclined in
the opposite direction to what it was before so that there is no tendency for the iron
core to return to its former position. To increase the magnetic pull of the solenoid
upon the movable core a short fixed iron core is sometimes fitted in the end of the
solenoid farthest from the mercury cups. The instrument is reset to complete the
circuit by turning the coil system on its pivots until the end connections are fully in
the mercury cups when the movable core will fall into its position by the action of
gravity or may be pushed down by a plunger provided for that purpose. The value
of the current at which the cut out acts may be varied between certain limits by
adjusting the stop screw which determines the normal position of the movable core or
by altering the angle at which the coil system rests.
:
We may construct the Instrument so that the current to be broken is independent
of that on the solenoid. For instance the solenoid inay be wound with fine wire of

page_text: bigh resistance and be connected across from the positive to the negative mains while
the mercury cups at which the break takes place may be in the main circuit so that
the Instrument acts as an Electro Motive Force Cut out.
Our invention may be used for purposes other than that of breaking an electrical
circuit.
We may use the combination of the moving coil with its movable core to produce
in any apparatus motion from one position to another when an electric current of
sufficient strength is passed through the coil. The action of the moving coil system
may also complete instead of break an electric circuit, or may do both by arranging
suitable contacts at the end of the coil furthest from the mercury cups.
The accompanying shoot of drawings will further illustrate our invention.
Figure 1 is an end elevation.
Figure 2. a front elevation and Figure 3 a plan of a "Cut-out" constructed
according to our invention. Similar letters of reference indicato like parts in all the
figures.
A is a base plate of suitable material such as porcelain or slate. B is a non-
magnetic metal tube on which is wound the coil C. between the and cheeks C³ C".
D. D are the end connections of the coil which in the cut out illustrated is intended
to be made of thick wire and to be included in the main circuit. If the apparatus is
to be used as an electro motive force "Cut out" the coil would be wound with fine
wire having a bigh resistance and with its ends suitably connected to separate
terminals; in this case the arms D D' would be electrically joined together so as
simply to connect the mercury cups E. E'. These mercury cups in both cases form
the main terminals of the cut out, holes for the cable connections and clamping screws
being provided in their lower ends.
Gis the soft iron sperical coro, H the fixed core and J the yoko by which the
whole coil is supported through the pivot screws L L' carried by the bracket.
K. M is a stop pillar to limit the notion of the coil in one direction and N a stop
bracket which may be fitted with an adjustment screw to limit the motion in the other
direction.
P. is a plunger held back by a spring and which is used to force the core back
against the adjustment screw S. This sorow may be of iron or other metal and it is
carried by the end plug R. of the coil tube.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare what wo
claim is :-
1. The combination of a moving coil (. with a moving coro G substantially as and
for the purposes herein before described.
2. The construction and use of Electrical Instruments which when the current
reaches a certain value automatically act by reason of a movable iron core displacing
the centre of gravity of the coil system.
3. The construction and use of electrical contact bronkers or contact, makers which
when the current reaches a certain value, automatically act by reason of a movable
iron core being attracted into a pivotted coil and so displacing the centre of gravity
of the coil system.
1
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