Improvements in Electric Meters.
Year: 1889

page_text: Date of Application, 9th July, 1889
Complete Specification Left, 5th Apr., 1890-Accepted, 28th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in Electric Meters.
We JOSEPH OULTON, of 232 Otley Road, Bradford in the County of York, Clock
maker, and JOSEPH EDMONDSON of 36 Sunbridge Road, Bradford, in the County,
aforesaid, Electric Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in Electric Meters in which the current is
measured by its influence on the time of rotation or oscillation of balances or pendulums
driven by clockwork.
These improvements consist :-
In the mode of regulating the time of rotation of "Torsion balances," in electric
meters. We attach the torsion ribbon (by which such balances are suspended) to the
stem of a screw, or to a lever by which it is raised or lowered through a curb, such
raising or lowering shortens or lengthens the acting portion of the ribbon and thus
increases or lessens the speed of rotation as may be required.
To compensate for the effect of variations of temperature we employ a compensating,
rod, ribbon or wire which by its expansion or contraction moves a curb on the torsion
ribbon and varies the length of the acting portion of the ribbon, to such an extent
as may balance the effect of temperature upon the said torsion ribbon. Or we cause
the said compensating rod, ribbons or wire to raise or lower the said torsion ribbon
through a fixed curb.
We place the axis of the torsion balance in the same line as the axis of the balance
staff of the clockwork from which it is to receive its impulse, or in the same line as
the axis of the impulse pallets, according as the escapeinent is or is not of the kind
known as detached.
In some cases we accomplish this by means of a crank or stirrup attached to the
balance or torsion ribbon.
"
In order to secure the advantages of the "chronometer escapement" without its
delicacy of construction or action, we use what we term a "detached duplex
escapement consisting of a scape wheel having locking teeth which are locked by a
spring locking pallet) and impulse pins half as many as there are locking teeth and
necessarily an odd number. The impulse pallets are placed on the balance staff, which
is at a right angle to the axis of the scape wheel, and which also carries the unlocking
pallet. In some cases we employ a lever escapement in which the fork of the lever
is at a right or other convenient angle to the plane of the motion of the lever.
In electric meters we influence the balance either by placing a permanent magnet
upon it (or upon the stirrup or torsion ribbon) which travels within range of a fixed.
solenoid or solenoids with or without iron cores or pole pieces through which passes
the current to be measured.
Or we place the solenoid or solenoids upon the balance the permanent magnet
being then fixed.
If the permanent magnet be replaced by a coil of high resistance shewing the
volts of the current to be measured, and thus making the instrument into a Watt
meter, we use in the case of alternating currents, a fixed high resistance coil wound
to eliminate self induction as far as possible in conjunction with the coil upon the

page_text: balance which may then be composed of but few wraps of wire. In some cases we
calibrate the instruments by means of adjustable cores or pole pieces.
In others we employ for this purpose a shunt of variable resistance from the main
current.
We also influence the torsion balance by the heating effect of the current to be
measured, or a known proportion of it. This is effected by passing the current
along the torsion ribbon which causes it to expand and lessens the speed of the balance.
Or the current may be passed along a rod or ribbon or wire attached to a curb by
which it increases or lessens the acting length of the torsion ribbon. Or the said rod
or ribbon or wire may be so connected as to lower or raise the torsion ribbon through
a fixed curb, which will have the same effect.
In the case of pendulums the current may in like manner be passed through a rod
ribbon or wire which shall alter the position of the pendulum in relation to its curb,
or through the pendulum rod itself.
The heat generated by an electric current being in proportion to the square of the
said current, whereas the measurement is required to be in proportion to the current
only, to eliminate the error that would otherwise arise we pass the current which is
to influence the balance or pendulum through an instrument which automatically
reduces the amount passed through the measuring bar, ribbon or wire, to the square
root of the whole or of a known proportion of it. This instrument may be a trans-
former the secondary coil of which is so suspended or pivoted and so regulated by
a curb or spring or weight, as automatically to adjust itself to give the requisite
proportion of current.
The suspension of the transformer may be a torsion ribbon.
In lieu of the method of driving two balances or pendulums from the opposite ends
of one main spring or one weight as described in our application No. 14843 and
dated 16th day of October 1888, we drive from one end of the spring or from the
driving weight through a differential gear which equally distributes the force between
the two balances or pendulums.
This differential gear may be the ordinary planet wheel between two crown or
bevil wheels. But we employ a gear in which only spur wheels and pinions are used.
One such form of gear consists of a pair of concentric wheels each working into a
planet wheel (or pinion). These planet wheels also gear into one another and are
fixed on one and the same revolving piece.
Another form consists of two unequal concentric wheels, gearing into two unequal
planet wheels, (or pinions) fixed together concentrically on the same stud on a
revolving piece. We also use the aforesaid differential gears for recording the
difference of time between the two balances or pendulums.
Dated this 8th day of July 1889
WALTER
BRIERLEY,
Central Chambers, Halifax, Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electric Meters.
We, JOSEPH OULTON of 232 Otley Road, Bradford in the County of York Clock
Maker and JOSEPH EDMONDSON of 36 Sunbridge Road, Bradford in the County
aforesaid, Electric Engineer, 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 :-
This Invention relates mainly to Electric Meters in which the current to be
measured is made-to-retard or accelerate the vibrations of a pendulum or chrono-
metrie-bulance, the amount of such retardation or neceleration being the measure-of
the current consumed. Instead of a single-magnet on or connected to, or itself forming a
torsion-balance as described in the Specification of a Patent No. 14243 granted to us
on the 16th-October 1888, we use a pair or pairs of magnets-placed "ustatically"
. 2

page_text: that is with their poles-reversed, so as to neutralise the influence of the earth's
magnetism, and to reduce the effect of other external-influences: We-also-substitute
a pair of solenoids placed astatically for the single solenoids on the torsion balance as
described in the said Specification.
In place of the fixed solenoid or colenoids in Queneing the torsion balance (through
the-magnet or solenoid attached-to-it)-as described in the said Specification, we use
a single-conductor consisting either of one wire or its equivalent) or of several wires
(or their equivalents-coupled in paralle!) placed so as to influence the magnets-or
solenoids attached to the balance.-Such-conductor may be either straight or bent-to
and fro, over and under, the-said-magnets or solenoids, so as to increase-the-influence
of the current, or it may be passed in parallel above and below in different proportions
or at different distances, so as to diminish the said in quenee.
In the ease-of-a-pendulum-we-use-either-an-horse-shoe-magnet, or-astatie-magnets
instead of the straight magnet (whether single- or compound) hitherto used, and we
earry the current in the vicinity of the poles by a-single-conductor-as before described
mutatis mutandis.
The calibration of the instrument-may-be-effected by varying the distance of the
aforesaid conductor-(or a part of it)-from-the-magnet or solenoid to be influenced by
the current to be measured.
In order the better to protect the-magnets-or-solenoids on a torsion-balance from
external magnetie influence, we-surround-them-with-iron, either-fixed-and-having
the balance rotating within it or forming-the-whole or a portion-of-the-balance.
We-correet the-want-of-proportionality in the record-of-Watt meters by a supple-
mentary solenoid-or coil-on-the-pendulum or balance-through which-is-passed-n-small
fraction of the-current-to-be-measured: -The influence-of-the-main-current-on-this
solenoid being-in-proportion to-the-square-of-the-fraction-of-the-earrent-passing
through the latter, will-correct-the-small-error which-would-otherwise arise-in-the
register. In-Coulomb-meters-for-alternating-currents-we-use-a-similar-supplementary
eurrent through a solenoid or coil either on, or fixed in the vicinity of the balance
or pendulum.
For the purpose of adapting electrie-meters-of-any kind without recalibration-to
currents of differing electro-motive force, we insert,-at-some-convenient-point-for
driving the registering train, a change wheel, which we-term-a "Volt-Wheel." By
preference-the-number-of teeth in this wheel is the same as the number of volts in the
electro-motive force of the current-to-be-measured:
This invention relates to improvements in electric meters in which the current is
measured by its influence on the time of rotation or oscillation of balances or pendulums
driven by clockwork.
These improvements consists:-
a
In the mode of regulating the time of rotation of "Torsion balances" in electric meters.
We attach the torsion ribbon (by which such bulances are suspended) to the stem of
screw, or to a lever by which it is raised or lowered through a curb, such rising lowering
shortens or lengthens the acting portion of the ribbon and thus increases or lessens the speed
of rotation as may be required.
ur
To compensate for the effect of variations of temperature we employ a compensating
rod, ribbon or wire which by its expansion or contraction moves a curb on the torsion
ribbon, and varies the length of the acting portion of the ribbon, to such an extent as
Or we cause the
may balance the effect of temperature upon the said torsion ribbon.
said compensating rod, ribbons or wire to raise or lower the said torsion ribbon through
a fixed curb.
We place the axis of the torsion balance in the same li..e as the acis of the balance staff
of the clockwork from which it is to receive its impulse, or in the same line as the acis
of the impulse pallets, according as the escapement is or is not of the kind known as
detached.
In some cases we accomplish this by means of a crank, or stirrup attached to the balance
or torsion ribbon
"In order to secure the advantages of the "chronometer escapement" without its delicacy

page_text: of construction, or action, we use what we term a "detached duplex" escapement
consisting of a scape wheel haring locking teeth (which are locked by a spring locking
pallet) and impulse pins half as many as there are locking teeth and necessarily an. odd
number. The impulse pallets are placed on the balance staff, which is at a right. angle
to the axis of the scape wheel, and which also carries the unlocking pallet.
In some cases we employ a lever escapement in which the fork of the lever is at right,
or other convenient angle to the plane of the motion of the lever.
In electric meters we influence the balance either by placing a permanent magnet upon
it (or upon the stirrup, or torsion ribbon) which travels within range of a fixed solenoid, or
solenoids with, or without iron cores, or pole pieces through which passes the current to be
measured.
Or we place the solenoid, or solenoids upon the balance the permanent magnet being then
fixed.
If the permanent magnet be replaced by a coil of high resistance shewing the volts of
the current to be measured, and thus making the instrument into a Walt meter, we use in
the case of alternating currents, a fixed high resistance coil wound to eliminate self
induction as far as possible in conjunction with the coil upon the balance which may then
be composed of but few wraps of wire. In some cases we calibrate the instruments by
means of adjustable cores or pole pieces.
In others we employ for this purpose a shunt of variable resistance from the main
current.
We also influence the torsion balance by the heating effect of the current to be measured,
or a known proportion of it.
This is effected by passing the current along the torsion ribbon which causes it to expand
and lessens the speed of the balance. Or the current may be passed along a rod, or
ribbon, or wire, attached to a curb by which it increases, or lessens the acting length
of the torsion ribbon. Or the said rod, or ribbon or wire may be so connected
as to lower, or raise the torsion ribbon through a fixed curb, which will have the
same effect.
In the case of pendulums the current may in like manner be passed through a rod,
ribbon or wire which shall alter the position of the pendulum in relation to its curb, or
through the pendulum rod itself.
The heat generated by an electric current being in proportion to the square of the said
current, whereas the measurement is required to be in proportion to the current only, to
eliminate the error that would otherwise arise we pass the current which is to influence the
balance or pendulum through an instrument which automatically reduces the amount
passed through the measuring bar, ribbon or wire, to the square root of the whole, or of a
known proportion of it. This instrument may be a transformer, the secondary coil of
which is so suspended, or pivoted and so regulated by a curb or spring or weight, as
automatically to adjust itself to give the requisite proportion of current.
The suspension of the transformer may be a torsion ribbon.
In lieu of the method of driving two balances, or pendulums from the opposite ends of
one main spring or one weight as described in our application No. 14843 and dated
16th day of October 1888, we drive from one end of the spring, or from the driving weight
through a differential gear which equally distributes the force between the two balances or,
pendulums.
This differential gear may be the ordinary planet wheel between two crowns, or bevil
wheels. But we employ a gear in which only spur wheels, and pinions are used.
One such form of gear consists of a pair of concentric wheels each working into a planet
wheel (or pinion).
These planet wheels also gear into one another and are fixed on one and the same
revolving piece.
Another form consists of two unequal concentric wheels, gearing into two unequal
planet wheels, (or pinions) fixed together concentrically on the same stud on a revolving
piece. We also use the aforesaid differential gears for recording the difference of time
between the two balances or pendulums.
Such being the nature and object of our said invention the following is a

page_text: complete description or same the numerals on the drawings reter to the same parts
throughout.
It
Fig. 1. shews a torsion balance as mounted for the purpose of our invention.
consists of a weight or balance 1 (preferably cylindrical) suspended by an elastic ribbon 2.
of any suitable material (preferably of steel) from a lever pivoted at 4 and held
down by an adjusting nut 5. The said ribbon passes through a slot in the curb 6,
large enough to allow the ribbon to rise and fall freely but not to twist within it. A
rod (or rods) 7 having its upper end firmly fixed & its lower end attached to the
curb 6. expands or contracts with variations of temperature and compensates for
similarly caused expansion or contraction of the ribbon. When the adjusting nut 5
is screwed down it raises the opposite end of the lever 3 and thereby draws a portion of
the ribbon 2 through the curb 6 shortens the acting length of the ribbon therefore
quickens the speed of the balance. When the said nut is screwed up the contrary
effect is produced.
The ribbon 2 passes round pins in a stirrup or crank 8 admitting of the axis of
the balance staff of the clockwork hereinafter described being placed in a direct line
with the axis of the balance and of the acting part of the ribbon (see Figs. 7 12
and 25).
When the balance 1 is rotated round its axis the torsion of the ribbon 2 will tend
to bring it back to its position of rest or zero and in doing so will cause it to rotate or
oscillate to and fro. Its rotations may be maintained and recorded by ordinary
clockwork as hereinafter described.
A filament or wire may be substituted for the ribbon 2 provision being made by
flattening or otherwise where it passes through the curb 6 for the latter to regulate its
acting length.
Fig. 2, 3 and 4 shew various forms of stirrup 8. In Fig. 4 the stirrup consists of a
tube through which the ribbon 2 passes the ends of the tube being flattened to prevent
the ribbon twisting within it. This stirrup as well as that in Fig. 1 can be moved
along the ribbon to any required position.
In Fig. 5 the curb 6 is placed & the regulating lever 3 is fixed upon a second
lever 3 to one end of which is attached one end of the compensation rod 7.
In Fig. 6 the balance is suspended on "compound bars" 9, 10 after the manner of
the well known gridiron pendulum the upper ends of the bars 10 being firmly fixed
to the plate 11 while the other ends are free to move downwards and have attached
to them a crossbar 10 carrying the bars 9 which are free to move through holes 9 in
the plate 11, their upper ends being attached to the plate 11 which carries the
balance by means of a ribbon 2 passing through the slot 6 in the plate 11 which
acts as the "curb." The bars 9 are of a metal more expansible by heat than that
of which the bars 10 are composed their respective lengths are so adjusted as to
compensate for the variations in length of the torsion ribbon caused by variations of
temperature.
Various methods of communicating the impulse to be given to the balance by the
clockwork train are shewn in Figs. 7 to 15 inclusive Fig. 7 is an elevation and
Fig. 8 a plan of a scape wheel and other parts of a lever escapement placed with
the axis parallel to the axis of the balance. Figs. 9 and 10 shew in elevation and
plan respectively a similar escapement with the axis of the scape wheel (and
consequently the axis of the wheels preceding it in the clock train) at right angles to
the axis of the balance.
In Figs. 7 and 8, 13 is the scape wheel 14, 14 are the pallets 15 is the lever, 16 the
balance staff; 17 a fork or crutch, attached to the balance staff 16 and giving the
impulse to the balance through the stirrup 8. In Figs. 9 and 10 it will be seen that
the end 15 of the lever 15 is bent over at a right angle alter the manner of the teeth
of a crown wheel so as to give the impulse to the balance staff 16 placed at a right
angle to the axis of the lever 15. In this case the balance is suspended with its axis
directly over and in the same line as the axis of the balanca staff and receives its
impulse through a pin 18 and the fork 17. It will be obvious that the methods of
conveying the impulse from the balance staff to the balance by a stirrup as in.

page_text: Figs. 7 and 8 or by a pin under the balance as in Figs. 9 and 10 are mutually
interchangeable.
"
"
A dead beat escapement is shewn in elevation and plan in Figs. 11 and 12. The
axis 19 of the pallets 14 is in the same line as the axis of the balance and has
attached to it the fork 17 which gives the impulse to the stirrup 8. Similar
arrangements may be applied to an ordinary "duplex cylinder" or verge" escape-
ment in which the impulse pallets are always placed on the balance staff.
Figs. 13 and 14 shew in elevation and plan respectively our detached duplex
escapement Fig. 15 being an enlarged elevation of a portion of the same. On the
scape wheel 13 are impulse pins 20, 20ª, 20° (half as many as there are teeth in
the scape wheel and necessarily an odd number). The balance staff 16 carries the
unlocking pallet 21 which as it passes the pin 22 at the end of the locking spring 23,
raises it with its locking pallet 24 and so unlocks the scape wheel. The balance
staff 16 also carries two bosses or "rollers" from the faces of which project the pin
pallets 25 and 25ª. The action is as follows-As shewn in the drawings the balance 1
and balance staff 16 are moving in the direction of the arrow placed on the former
and have just passed the neutral or dead point. The unlocking pallet 21 has
partially lifted and is on the point of disengaging the locking pallet 24, and the pin
pallet 25 is ready to receive the impulse from the impulse pin 20ª seen close to it.
When the locking pallet 24 is disengaged by the further progress of the balance staff,
the scape wheel is liberated and gives the impulse.
The balance and balance staff being then detached from the escapement still going
forward and the locking pallet drops and locks the scape wheel. On the return of the
balance and balance staff the locking pallet is again lifted as the unlocking pallet 21
passes the pin 22 the pin pallet 25ª comes into position for receiving and then receives
the impulse from the impulse pin 20" in the direction opposite to that of the first
named impulse given to the pin pallet 25. The locking pallet again drops and locks
the scape wheel while the balance is completing its axis of oscillation and then
returns. This operation is repeated continuously. A small screw 26 adjusts the
depth of the locking. Instead of the pin pallets 25, 25" we may substitute a notch
in each roller one side of each notch forming the impulse surface or pallet. A "fly"
may be placed on the scape wheel arbor to soften the locking.
"
In Figs. 16 (elevation) and 17 (plan) 28 is a solenoid to carry the current to be
measured with an iron core having annular polar extensions 29 the one above and the
other below the balance 1 (which in this case is of non-magnetic metal) also the pole
pieces 30, 30 into one of which is inserted an iron screw 31 for calibrating. The
balance carries a permanent magnet 32 which travels between the annular pole
pieces 29 placed concentrically with the balance. When no current is passing
through the solenoid 28 there is a constant influence between the pole pieces 29 and
the magnet 32 tending to draw the balance to the position shewn in the drawing,
which is the "dead" point or point of zero or rest. When the current is passing in
one direction it increases the attraction between the magnet 32 and the pole pieces 29
and therefore quickens the oscillations of the balance but when passing in the other
direction it has the opposite effect the acceleration or retardation of the balance is a
measure of the current consumed within certain lands. The variation of time so
caused may be ascertained by comparing the rate of the influenced balance with that
of a clock keeping normal time.
The screw 31 increases or lessens the influence of the pole pieces 29 on the
magnet 32 (when the current is passing through the solenoid 28) according as its
top 31 is adjusted to a greater or lesser distance from the pole pieces 30%. If the
magnet be removed from the position 32 to the position 33 the influence of the current
will be reversed accelerating where, before it retarded and vice versa.
A coil or
solenoid of high resistance may be substituted for the permanent magnet in which
case the instrument will become a Watt Meter. In this case the connection of the
high resistance coil or solenoid with the main carrying the current may be as described
in Fig. 8 of our Specification No. 14843 of the year 1888. For alternating currents
we may influence the balance by the heating effect of the currents this may be done

page_text: by passing the current to be measured or a known portion of it through one pair
(either 9, 9 or 10, 10) of the compensating bars shewn in Fig. 6 such bars being
properly insulated. If passed through 9, 9 it would shorten the acting length of the
torsion suspension spring and quicken the vibrations of the balance. If passed
through 1, 10 it would have the contrary effect.
Or it may be passed through the torsion suspension ribbon the bottom of which for
this purpose may be metallically connected with the circuit through a mercury cap
as shewn in Fig. 18 in which the current after passing through the torsion ribbon 2
from the terminal 44 is conveyed by the wire 46° into the mercury cup 54 which is
connected with the circuit by the conductor 46d.
In arrangements such as shewn in Figs. 1 and 5 the current may be passed
along the compensating rods 7. In both these cases it will increase the speed of
the balance.
When it is required to influence two balances in opposite directions by the heating
effect of the current we may use the metho illustrated by Figs. 19, 20.
From one
end 38 of a lever 38 moving on a pivot 39 is suspended one of the balances. Upon
the lever 38 is placed the regulating lever 40 which carries the other balance, bat so
that its torsion ribbon passes over and rests against the curved end 38" of the said
lever 38. The weight 38 keeps the said lever 38 pressing upon the upper end of the
rod 41 which rests on the cross bar 43 suspended by the wires or metallic
ribbons 42, 42 from insulated terminals 44, 44 to which the wires 46°, 46, carrying
the current are to be attached. The rod 41 and the wires 42 should be of the same
metal so as to be self compensating for ordinary changes of temperature.
If of different metals their lengths should be so proportioned as to give a like
result. When the current to be measured (or a known proportion of it) is passed
between the terminals 44, 44 through the wires and cross bar 42, 43. 42 the wires
expand and permit the weight 38 to force its own end of the lever 38 downwards
thereby lengthening the acting part of the torsion spring of the one balance, and
shortening that of the other and setting up a variation from their normal speed in
opposite directions which variation may be recorded as described in our Specification
of Patent No. 14,843 of the year 1888 or by means of any other suitable differential
gear and registering dials.
An electric current passing through a wire developes heat in proportion to the
square of the current. In order therefore to register in proportion to the current
(instead of in proportion to its square) a correction must be applied. Such correction
would result from placing an instrument or apparatus in circuit with the measuring
wires 42, 42 (Figs. 19, 20) or the compensating bars 9, 10 (Fig. 6) or the torsion
ribbon Fig. 18 (or such other portion of the measuring instrument as is the medium
of measurement) by which the square root of the current or any known proportion of
it is alone allowed to pass through the said wires, bars ribbon or other medium.
Such instruments are shewn in Figs. 21 and 22. In Fig. 21 the two coils 45, 46
constitute a small transformer (for alternating currents) 45 being fixed and carrying
the primary current which it is desired to measure. The secondary coil 46 is
suspended at 48 by a torsion ribbon 47 preferably of steel and kept in tension by a
weight 50 attached to its lower end. The ribbon 47 passes through a slot 49 in the
plate 51 which acts as a curb. The regulation is effected by an adjustable curb 52
consisting of a slot in the bar 52 which may be raised or lowered by the nut 53.
The secondary current in the coil 46 is carried by the wires 45, 46' to mercury cups
as 54, 54" Fig. 22 whence it is conveyed to the measuring apparatus hereinbefore
described & thereby forms a closer circuit. It will be evident that a spring may be
substituted for the weight 50, the tension on which may be regulated by a screw
and nut.
In Fig. 22 the lower end of the torsion ribbon is fixed at 48. The plates carrying
the point of suspension 48 and the fixed attachment 48ª of the lower end of the torsion
ribbon are connected by pillars 55, 55 which if made of the same metal as the ribbon 47
will expand and contract with it under the influence of varying temperatures and will
maintain a uniform tension of the spring. When the alternating current passes

page_text: through the primary coil 45 it sets up an induced current in the coil 46 which causes
the latter to turn on its axis of suspension and thereby reduces the current which
would otherwise be induced in it. The curb 52 on the spring 47 may be so adjusted
that this induced current shall be equal to the square root of the primary current
passing through the coil 45.
66
Figs. 23 and 24 are a front and side elevation respectively of a set of clockwork
driving two balances through a differential gear according to our invention. The
going barrel" 66 on its winding arbor 67 has its main wheel gearing into the pinion 73
and driving the wheel train 73 73° 73° 73. The arbor of 73° is carried at its inner
end by the bracket or cock 74 which also carries the inner end of the arbor 75.
The arbor 69 of the pinion 73ª carries fixed upon it the disc 76 which in its turn
carries the pinions 72x 72" of a differential gear shewn in detail in Figs. 25 (front
elevation) 26 (side elevation) and 27 (plan). The wheels 71, 71" into which the said
pinions gear are fixed on tubular arbors which run freely on the arbor 69 and carry
the wheels 77, 77 which in turn drive the scape wheels 13, 13" which impel the
balance staffs as shewn in Figs. 9, 10. The said differential gear divides the force of
the driving spring equally between the two balances, whether their rate be normal and
equal or their be a difference set up between their rates by the current to be measured.
The balances are shewn without the apparatus for electrically influencing them which
may be constructed according to any of the methods already described.
The wheels 71, 71s are carried round in the same direction as the arbor 69 by means
of the disc 72 and the pinions 72* 72. When the two balances are vibrating at the
same rate the wheels 71, 71 also travel at the same speed and the pinions 72x 72 have
no motion round their own axis. But when a difference is set up between the rate
of the balances the pinions 72x 72 revolve in opposite directions round their own axis
to the extent required to maintain a constant and equal force from the driving train
upon each of the scape wheels. It will be seen that the differential gear may be
placed at any point in the train of wheels between the spring (or its equivalent) and
the scape wheels, and that this method of dividing the force is equally applicable to
the driving of pendulums.
The differential gear illustrated in Figs. 25, 26 and 27 is also applicable for recording
differences. For if the wheel 71 be in gear with one scape wheel and the wheel 71"
be in gear with the other so that the wheels 71, 71ª are driven in opposite directions
(and at the same speed when there is no difference to be recorded) and the arbor 69
be connected with a dial train or other recording apparatus it will record any difference
of speed which may arise between the two balances.
The sleeve or tubular arbor of the wheel 71 (Figs. 23, 24) carries a pinion 78
gearing into a wheel 80 fixed on the arbor 75. The sleeve or tubular arbor of the
wheel 71 carries a pinion 79, which when both balances are vibrating at the same rate
drives the whee! 80 at (by preference) half the speed of the wheel 80. The two
wheels 80, 80 drive a differential counter illustrated by Figs. 28 (elevation) and 29
(plan) and cause the index 81 to register on the dial 82 the differences of rate of the
balance set up by the current under measurement. In this differential gear the
hollow arbor or sleeve 81ª carries and is driven by the wheel 80 (Fig. 24) in the same
direction as the arbor 75 on which it rides but at (by preference) half the speed of the
latter. This hollow arbor is also fixed to the wheel 82 of the differential gear, and
gears into the pinions 83, 83ª which are fixed to and run on the same studs as, the
wheels 84, 84*. These again gear into the pinion 85 which is fixed on the arbor 75
which takes its motion from the wheel 80 (Fig. 24) fixed upon it. The studs of the
wheels and pinions 84, 84, 83, 83 are fixed into the flat bar 86 which carries the
index 81 on its tubular arbor or boss 86ª. When the balances are going at equal
rates, the bar 86 and with it the index 81 remain stationary, but when a difference
between the speed of the balances is set up by the current under measurement the said
bar with its index moves round its centre and registers the difference. It will be seen
that the wheels 83 84 may be omitted without affecting the result.
•
The differential gear illustrated in Figs. 28 29 may also be used for driving the two
balances. For if the tubular arbor 81* of the wheel 82 be connected with the driving

page_text: part of the train and the arbor 75 (on which is fixed the wheel 85) conveys the force
to one scape wheel and the tubular arbor 86 of the bar 86 conveys the force to the
other scape wheel the driving force will be equally divided between the two scape
wheels which will also be free to move independently of each other. It will also
be evident that the same differential gear may be used to record the differences
between the two balances by gearing the arbor 75 so as to be driven in one direction
from one 86 to be driven in the opposite direction from the other scape wheel as
described in reference to Figs. 25, 26, 27.
Figs. 30, 31 shew in front and side elevation respectively a mode of influencing the
rate of vibration of pendulums by the heating effect of an electric current for the
purpose of an electric meter. The bars, 9, 9 10, 10 and 2 constitute an ordinary
gridiron pendulum rod. The current passing through the mercury cup 35 the bars 9,9
(which are insulated and the mercury cup 35 will cause the bars 9, 9 to expand and
by lowering the centre of oscillation will lessen the speed of the pendulums vibrations..
Figs. 32, 33 shew an ordinary uncompensated pendulum as electrically influenced for
the purposes of an electric meter. The current passes through a double suspension
rod 9,9 (insulated) which is connected with the electrical circuit through mercury
cups 35, 35. It will be obvious that variations of speed set up by the current in
pendulums arranged as in Figs. 30 to 33 may be recorded by any of the arrangements
for that purpose described in this Specification, or in the Specification of our Patent
No. 14843 of the year 1888.
In the Specification just referred to there is described and claimed the combination
of two balances or pendulums and one spring or weight and where as in the present
arrangement there are two balances or pendulums, one spring and a differential gear,
the latter is applied as illustrated so as to enable us to use a simple "going barrel"
instead of a barrel and maintaining power; to dispense with several wheels heretofore
necessary at the lower part of driving train and give a nearer approach to uniformity
in the division of the driving power between the two scape wheels and balances. This
nearer approach to uniformity tends the more effectually to secure the synchronism of
the balances.
Having now particularly described and ascertained the nature and object of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
1. In electric meters the construction arrangement and use of a torsion balance
together with a staff from which it receives its impulse the axes of the said balance
and the staff being in one and the same straight line as herein described and
illustrated by annexed drawings.
2. In electric meters the construction arrangement and use of a stirrup or crank as
illustrated in Figs. 1, 2, 3, 4, 5, 7, 8, 10, 11, 12 through which the impulse is com-
municated to a torsion balance the staff from which the said stirrup receives its
impulse being placed in the gap of the stirrup so that the axes of the said balance and
the said staff shall be in one and the same straight line substantially as herein described
and illustrated by annexed drawings.
3. In electric meters the construction arrangement and combination of parts as
illustrated by Figs. 16, 17, as and for the purpose herein described.
4. In electric meters the use of appliances such as those illustrated by Figs. 1, 5, 6,
18, 19, 20, 30, 31, 32, and 33, whereby the heat from the passing current is utilized
so as to influence the speed of the balances or pendulum and to measure the current
consumed as herein set forth.
5. In electric meters the combination with a driving spring or weight and two
balances or pendulums (when one or both of said balances or pendulums is or are
influenced by an electric current for the purpose of measuring the said current) of a
differential gear for the purpose of dividing with a nearer approach to uniformity the
force of the said spring or weight between the said balances or pendulums so as the
more effectually to secure their synchronism as herein described.
6. In electric meters the differential gear when constructed as herein described and

page_text: illustrated by Figs. 25, 26 and 27 and two balances or pendulums all in combination
as and for the purposes herein described.
7. In electric meters the differential gear when constructed as herein described and
illustrated by Figs. 28 and 29 and two balances or pendulums all in combination as
and for the purposes herein described.
JOSEPH
OULTON.
JOSEPH EDMONDSON.
By their Agent Walter Brierley,
Central Chambers, Halifax.
Dated this ord day of pin t
JOSEPH OULTON.
JOSEPH EDMONDSON.
By their Agent Walter Brierley,
Central Chambers, Halifax.