Improvements in Electrical Relays and Measuring Instruments.
Year: 1893

page_text: Date of Application, 7th Mar., 1893
Complete Specification Left, 7th Dec., 1893-Accepted, 3rd Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Electrical Relays and Measuring Instruments.
We, WILLOUGHBY STATHAM SMITH of 13 Courtfield Road, South Kensington,
in the County of Middlesex, Telegraphic Engineer, and WILLIAM PUDDICOMBE
GRANVILLE of 36 Oakfield Road, Stroud Green, in the County of Middlesex,
Electrician, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to construct delicate electrical measuring
instruments and relays.
For these purposes we rigidly attach two light coils of insulated wires, connected
in series, one to each end of an arm which is pivotted at its centre-a ring of soft
iron which is concentric with the axis of the arm is made to pass through each coil
without touching it so that the arm with the coils on its ends may swing freely-or
instead of two coils one large coil embracing the whole diameter of the ring might
be used.
We also for the most part surround each of the two coils by the pole of a magnet
one coil with one pole say north the other with the other that is south; the
magnet or magnets, as well as the iron ring are rigidly attached to the base
board.
By this means, each coil is placed in a strong magnetic field, since the iron ring
is magnetised by induction. The iron ring can if wished be replaced by another
magnet, so placed that its south pole is in proximity to the north pole of the
surrounding magnet or magnets.
The current can conveniently be conducted to the coils by means of two fine
perpendicular wires placed on the pivotted arm symmetrically one on each side of
the pivot, the wires being kept tight by weak spiral springs. These wires, by their
tension also serve to keep the coils normally at their zero position, i.e. at those
parts of the ring which are surrounded by the magnetising magnets. For extremely
sensitive purposes the pivots may be dispensed with and the system may simply be
suspended by the conducting wires, arranged either as above or suspended from
top and bottom or other means may be adopted for conveying current to
the coils.
The instrument so arranged can be used as an electrical testing instrument (the
coil system being rotated by the electric current) and a pointer or mirror being
attached to the arm or pivot. Or it may be used as a simple relay, the arm being
then provided with a platinum contact, which, when a current circulates, is caused
to swing against a fixed contact stud or pin attached to the base or framework of
the instrument.
When using this instrument as a relay for feeble currents of variable intensity,
for instance in the case of a long submarine cable we place upon the arm two
contact points at a slight distance apart and facing one another we also suspend
from the arm a light blade of metal which hangs between these points and at its
lower end dips into a reservoir containing oil, glycerine, mercury, or other viscid
fluid, the purpose being to retard the rapidity of movement of the lower part of the
blade, so that when the arm is at rest in any position the blade by gravity hangs
perpendicularly but on the slightest movement of the arm in either direction the
blade is temporarily deflected either to the right or left and is thereby caused to
make contact with one or other of the two contact screws and thus close the local
circuit. By this means the instrument is unaffected by either permanent or slow
earth currents and only responds to comparatively rapid currents the limit of

page_text: variation being governed by either the viscosity of the fluid or the amount of
surface of the blade immersed.
The blade may be pivotted so as to be free to move horizontally and the end
bent at right angles so as to dip into the fluid cup. In this case instead of using
gravity the normal central position of the blade i.e. midway between the two
contact screws may be obtained by a hair spring or by two weak opposing springs
attached to the arm.
Dated this 7th day of March 1893.
WILLOUGHBY S. SMITH.
W. P. GRANVILLE.
COMPLETE SPECIFICATION.
Improvements in Electrical Relays and Measuring Instruments.
We, WILLOUGHBY STATHAM SMITH, of 13 Courtfield Road, South Kensington,
in the County of Middlesex, Telegraphic Engineer, and WILLIAM PUDDICOMBE
GRANVILLE, of 36 Oakfield Road, Stroud Green, in the County of Middlesex,
Electrician, 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:—
The object of this invention is to construct delicate electrical measuring instru-
ments and relays.
For these purposes we rigidly attach two light coils of insulated wires, .connected
in series, one to each end of an arm which is pivotted at its centre-a ring of soft
iron which is concentric with the axis of the arm is made to pass through each coil
without touching it so that the arm with the coils on its ends may swing freely-or
instead of two coils one large coil embracing the whole diameter of the ring might
be used.
We also for the most part surround each of the two coils by the pole of a magnet
one coil with one pole say north the other with the other that is south; the magnet
or magnets, as well as the iron ring are rigidly attached to the base board.
By this means, each coil is placed in a strong magnetic field, since the iron ring
is magnetised by induction. The iron ring can if wished be replaced by another
magnet, so placed that its south pole is in proximity to the north pole and the north
pole to the south pole of the surrounding magnet or magnets or if a single coil be
used the surrounding magnet pole may be one of the poles of a single magnet whilst
the other pole of this magnet is made to pass through the coil.
The current can conveniently be conducted to the coils by means of two fine
perpendicular wires placed on the pivotted arm symmetrically one on each side of
the pivot, the wires being kept tight by weak spiral springs. These wires, by their
tension also serve to keep the coils normally at their zero position, i.e. at those parts
of the ring which are surrounded by the magnetising magnets. For extremely
sensitive purposes the pivots may be dispensed with and the system may simply be
suspended by the conducting wires, arranged either as above or suspended from top
and bottom or other means may be adopted for conveying current to the coils.
The instrument so arranged can be used as an electrical testing instrument (the
coil system being rotated by the electric current) and a pointer or mirror being
attached to the arm or pivot. Or it may be used as a simple relay, the arm being
then provided with a platinum contact, which, when a current circulates, is caused
to swing against a fixed contact stud or pin attached to the base or framework of
the instrument.
When using this instrument as a relay for feeble currents of variable intensity,
for instance in the case of a long submarine cable we place upon the arm two
contact points at a slight distance apart and facing one another we also suspend

page_text: from the arm a light blade of metal which hangs between these points and at its
lower end dips into a reservoir containing oil, glycerine, mercury, or other viscid
fluid, the purpose being to retard the rapidity of movement of the lower part of the
blade, so that when the arm is at rest in any position the blade by gravity hangs
perpendicularly but on the slightest movement of the arm in either direction the
blade is temporarily deflected either to the right or left and is thereby caused to
make contact with one or other of the two contact screws and thus close the local
circuit. By this means the instrument is unaffected by either permanent or slow
earth currents and only responds to comparatively rapid currents the limit of
variation being governed by either the viscosity of the fluid or the amount of surface
of the blade immersed.
The blade may be pivotted so as to be free to move horizontally and the rod bent
at right angles so as to dip into the fluid cup. In this case instead of using gravity
the normal central position of the blade i.e. midway between the two contact screws
may be obtained by a hair spring or by two weak opposing springs attached to
the arm.
Figure 1 is a longitudinal vertical section Figure 2 a plan and Figure 3 a trans-
verse vertical section of one form of relay constructed as above described. Figure 4
shews an alternative method of forming the relay contacts.
Figures 5 to 10 shew another form of the relay.
Figure 5 is a vertical section, Figure 6 a plan of the apparatus, Figure 7 is an
elevation of the bearings and supports for the pivot of the swinging arm.
Figure 8 is a side elevation on a smaller scale and Figure 9 a plan of the magnets
and case in which they are enclosed. Figure 10 is an edge view of the magnets
without the case.
In Figures 1 to 4 A. is a soft iron ring supported horizontally above a stand or
base B. CC are two similar coils surrounding this ring at opposite points-these
are carried at the two ends of a bar D which is suspended at its centre by wires E
one passing upwards from it and the other downwards to fixed pins F F' which can
be set either higher or lower to suspend the coils at such a height that the ring
passes through them without touching.
GG are two strong permanent horse shoe magnets supported from the_stand B
one above and the other below the plane in which the coils C swing and so that
the north poles of both magnets come above and below one coil and the south
poles above and below the other coil whilst the portion of the soft iron ring A which
lies between the north poles is by induction magnetized south and that between the
south poles north. The coils are wound in series one end of the wire is connected
to the pivot wire E which passes upwards to the pin F and the other to the wire E
which passes downwards to the insulated pin F₁ and binding screw F². This
binding screw is coupled by an insulated wire with a terminal binding screw H¹
whilst the terminal binding screw H is coupled to the metallic bed B₁ which rests
on the wooden bed B and is so in metallic connection with the pin F. The feeble
currents by which the relay is to be actuated are led to the instrument by wires
coupled to the terminals H H'. I is an indicator hand extending from the bar D
-by it it can be seen whether the bar D is at right angles to the magnets or
inclined to them-if it be inclined it can be set at right angles by turning slightly
the upper pin F so putting torsion on the wire.
When the indicator hand is in a central position the pin F can be held firmly in
the clamp F by turning the screw F*.
K is a light strip of metal suspended by a spring K' from an upward projection
at one end of the swinging bar D. LL are two contact points facing one another
on opposite sides of the suspended strip of metal K-these are carried by but are
insulated from the arm D.
An insulated wire is led from these contact points to terminal M' whilst
terminal M is in metallic connection through bed plate, uprights, upper suspension
wire &c. with spring by which K is suspended.
To the terminals M M' are also connected wires from opposite ends of the local

page_text: circuit. The lower end of K dips into a trough N containing castor oil or glycerine
or other viscid liquid.
So long as K hangs vertically it is out of contact with both points L. If the
arm D turns slowly K will still hang vertically as the lower end of K will have
time to move through the viscid liquid but if any quick turning movement of D
occurs then the lower end of K being unable to move quickly through the viscid
liquid K will be brought into contact with one or other contact point L and the
battery circuit will be completed-it may be through a bell or other instrument
for calling attention.
In place of using the soft iron ring which becomes magnetized by induction-a
permanent magnet might be substituted for it the south pole passing through the
coil surrounded or for the most part so by the north poles of the other magnets and
the north pole passing through the coil surrounded by the south poles of those
magnets or if a single coil is used then one pole of a permanent magnet or set of
magnets may be made to surround the exterior of the coil and the other pole be
made to pass through the coil.
This construction is shewn in Figures 5 to 10. In these figures A A are a
number of strong permanent magnets set vertically side by side. A' is a block
of iron fitting upon the top of one pole of the magnets and A² a block fitting upon
the top of the other pole. B is a cylindrical coil carried by a swinging arm C-
A³ is an iron rod passing loosely through the coil B and carried at its ends by
arms extending from the block A'-A' is a projection from the block A surrounding
loosely the exterior of the coil with the exception of a slit in it for the swinging
arm to pass through-C¹ is a vertical spindle from which the arm C extends-the
arm is also supported by two wires C2 passing up from it near to and on opposite
sides of the spindle to one end of two light coiled springs C³-the other ends of the
springs are attached to silk threads C which can be wound up more or less upon
pins C the weight of the arm C and parts carried by it can so be supported and
the arm kept in a horizontal position with little or no friction between the spindle
and its bearings. The two wires also give the coil its zero position. The arm C is
extended beyond the spindle and carries a small cup D containing castor oil or
glycerine or other viscous liquid.
To allow of an electric current being passed through the coil one of the suspending
wires C is coupled to one end of the coil and the other wire to the other end-the
arm C is of insulating material to keep the wires insulated from one another. One
wire is connected by a light flexible wire Cx with one of the metal pillars G and
the other by another wire C* with the other metal pillar G. The lower end
of one pillar is connected by a wire with the terminal X and the lower end of the
other with the terminal XI. Both pillars project up from the top of the casing
within which the magnets are enclosed and both are insulated from it.
E is a metal blade resting at E' in metal bearings on an arm E2 which is carried
by but insulated from a fixed upright E³. The lower end of the blade dips into
the viscous liquid in the cup D-its upper end comes between the ends of two
pins F F. The pins are so set that normally the upper end of the blade rests
against a projecting piece of insulating material at the end of one of these pins F¹
and is out of contact with the end of the other pin F which is metallic.
If however the swinging arm C turns in a direction to move the upper end of
the blade away from the insulated pin it is brought into contact with the metallic
end of the other pin or if desired both pins may be metallic and the blade arranged
to hang normally between the two without touching either.
The arm E' and consequently the metallic blade E which rests upon it are by
the wire E connected with the terminal Z whilst the metallic pin F is through the
upright E and metallic cylindrical casing put in connection with another terminal Z'.
To these two terminals are also coupled wires from the poles of a relay
battery a bell or other indicator may be included in this battery circuit so that
when the circuit is closed by the upper end of the blade E coming against the
pin F the bell is rung or other indication given,

page_text: 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. An electrical measuring instrument composed of a coil of insulated conductor
attached to one end of a horizontal balanced arm which can swing around a vertical
pivot one permanent magnet pole approximately surrounding the exterior of the
coil the opposite magnet pole passing through its interior and light connections for
passing through the coil the current to be measured.
2. An electrical relay composed of a coil of insulated conductor attached to one
end of a horizontal balanced arm which can swing around a vertical pivot one
permanent magnet pole approximately surrounding the exterior of the coil the
opposite magnet pole passing through its interior, light connections for passing
current through the coil and contact mechanism which completes a relay battery
circuit when the arm swings to one side when current is passed through the coil.
3. An electrical relay composed of a coil of insulated conductor attached to one
end of a horizontal balanced arm which can swing around a vertical pivot one per-
manent magnet pole contiguous to the exterior of the coil the opposite magnet pole
passing loosely through the interior of the coil, light connections for passing current
through the coil-a blade connected to one pole of a battery or local circuit dipping
into a cup of viscid liquid-a contact point connected with the other pole of the
battery or local circuit in proximity to the blade-the blade together with the
contact point, and the cup containing the viscid liquid being carried the one by or
with the arm and the other by a fixed support.
4. An electrical relay composed of a coil of insulated conductor attached to one
end of a horizontal balanced arm which can swing around a vertical pivot, a
permanent magnet or magnets, a continuation of one magnet pole formed to for
the most part surround the exterior of the coil, a continuation of the opposite pole
formed to pass through the interior of the coil, light connections for passing current
through the coil and contact mechanism for completing a relay battery circuit when
the arm swings to one side.
5. The construction of electrical relays and measuring instruments substantially as
herein before described with reference to Figures 1 to 4.
6. The construction of electrical relays and measuring instruments substantially
as hereinbefore described with reference to Figures 5 to 10.
Dated this 28th day of November 1893.
WILLOUGHBY S. SMITH.
W. P. GRANVILLE.