apparatus foruring
Year: 1887

page_text: I, HERMANN ARON, Dr. Philos., of Berlin, in the Kingdom of Prussia, German
Empire, 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 :-
My invention relates to improvements in apparatus for measuring electric currents,
of that class, for which I have obtained Letters Patent in Great Britain, No. 6770,
dated April 24th 1884.
For measuring or indicating the deviation of two sets of clock-work, and thereby
obtaining the amount of electricity supplied, I had according to the specification of the
afore-cited patent, constructed a differential counter, by which such deviations of the
indications of the two clocks were differentially formed by an exclusively geometrical
method and without any mechanism for connecting the two sets of clock-works. At
that time I did on purpose avoid all mechanical gear, and particularly any pressure
acting between the two clocks, for the purpose of preventing any irregularity in the
motion of either of them occasioned by the other. In the differential-counter
described in the aforesaid patent, there are, indeed, not even frictional resistances
acting as long as the two clocks are going the saine speed, as, in such case, the
relative positions of the moving parts of the two clocks do not the least change.
By experience, I have in the meantime found, that in clocks actuated by equal or
approximately equal power, for instance in two clocks driven by springs, or in two
clocks driven by weights, the difference of the indications may as well be formed by
means of mechanical devices connecting the two clocks, and causing the two clocks to
act upon each other, without occasioning any irregularities which might interfere with
the object to be obtained. On the contrary, even attain by such slight reciprocal
actions of pressure between the two clockworks, to compensate slight deviations in
the motion of the two clocks, in a manner, that, provided the duration of the vibrations
of the regulating devices he approximately equal, perfect synchronism is established
between the same.
In carrying my invention into practice, I arrange an intermediate differential-
counter between the two clock works, the deviations of which are to be indicated; said
differential-counter gears with each of the two sets of clock-works and indicates the
| deviations automatically on a series of dials.

page_text: In the accompanying drawings,
Figure 1 is a front elevation of an apparatus for measuring electric currents
embodying the improvements of my invention.
Figure 2 is a side elevation of the same.
Figure 3 is a plan, and
Figure 4 a modification of the translator, as will be hereinafter more fully described.
The two sets of clock work, the deviations of which are to be indicated, are placed
side by side in a casing and mark I and II, the dials are not shown, as they are usually
omitted, being not required for the purpose to be obtained. III is a differential-
counter placed between the two sets of clock-work I and II and having any convenient
number of dials to indicate the units, tens, hundreds and so on.
Motion is imparted to the differential counter III by means of the second wheels A
and A¹ of each of the sets of clockwork, but it is evident that any other pair of
corresponding wheels of the two works may as well serve for driving the intermediate
work. When using the third wheels, for instance, the motion of the differential-
counter will be quicker in proportion, and the indicator more sensitive.
The differential-counter consists of two crown-wheels B and B¹, having at the
same time a cylindrical gear opposite each other. The two crown wheels Figures 2
and 3, will turn in opposite directions, for which purpose an intermediate gear C
is arranged between the wheel A and crown wheel B.
Between the two crown-wheels B and B a planet wheel D is arranged, gearing with
both wheels B and B and being capable of turning at the same time round its
centre, and also of rolling along the cylindrical gear of the wheels B and B¹. The
axis d of this planet wheel D is vertically mounted upon an axis d' concentric with
the axis of the two crown-wheels. The axis of the front crown wheel B' is hollow
and the axis d' extends through the same; on this axis d' are mounted the gear e for
working the shafts for the dials of the differential-counter, and the finger e¹. The
planet wheel D may conveniently be balanced by a counterweight d².
The working order of this device may be easily understood.
Supposing one of the clock-works I or II to be at rest, the other moving, it will
be clear that the planet-wheel D will turn around the axis d', rolling along the circular
gear of the two wheels B and B₁; the axis d' being thereby turned, will advance the
finger e¹ on the dial and the other fingers on their dials with proportional speed.
The same result, but with less speed, will be obtained if both sets of clock-works
are moving one being fast or behind the other; the finger on the dial in this case
will indicate the deviations of the two sets of clock-work. In an apparatus of the
class referred to for measuring electric currents the vibrations of the pendulum p of
the clock-work II are either accelerated or slackened by the influence of the coil R,
or both pendulums p and p' may be influenced in the opposite sense. It will be
easily understood, then, that any deviations of the two sets of clock-work occasioned by
the influence of the electric current passing through the coil or coils, will be exactly
and automatically indicated on the dials of the differential-counter III. When there
is no current passing through the coil or coils, both sets of clock-works will go same
speed and both crown wheels B and B revolve at equal speed opposite each other;
the planet wheel, accordingly will keep its position as long as the synchronism
continues, and turning only around its centre à will leave the finger e¹ and all the
depending gear entirely at rest.
By this device all deviations of the two sets of clock-work are indicated, even if
occasioned by irregularities independent of the current to be measured, and occurring
at times when there is no current passing through the coil.
To reduce as much as possible such errors, I have further provided means in
apparatus of the class described, for measuring electric currents, which serve to stop
the clock or clocks of the apparatus during all the time when there is no current
supplied, and to set the clock or clocks immediately going, when the current enters.
In the drawings this device is shown applied to the two clock works I and II
arranged side by side, one of which being influenced, that is, made to g༠ fast or slow
by the current passing through the coil R. It consists of the combination of the

page_text: three levers E, F, and G, the lever E has its centre of motion at H, the lever G is
pivoted at J, and the lever F connects the two levers F and G, being hinged to them
at K and L. The lever E serves as an armature to the electro-magnet M. On the
pivots K and L, elbowed levers k and are loosely mounted, having each at the end of
one arm a nose or hook, and bearing with its other arm against an adjustable screw N
and O. Each of the hook-shaped arms & and engage with its nose, a corresponding
nose formed to an arm and l', extending from each of the pendulums p and p³ of
the clock-works.
It will be readily understood from the drawings, that, as soon as a current passes
through the electro-magnet M, the armature or lever E will be attracted, causing,
by means of the connecting-lever F, the lever G to swing the same distance aside.
By this simultaneous motion the elbowed levers k, l, resting against the screws N, O,
will be turned on their pivots K and L, and their upper, hooked arms thereby lifted
out of engagement with the hooks or noses of the arms and , which, accordingly,
are set free, permitting the pendulums to swing and the clocks to
It is of importance that the pendulums before being set free, be slightly lifted, in
order to fall from a position slightly elevated compared to the position where the
hooks engage. The hooks or noses are so shaped that the lever-arms kand in their
backward movement draw the pendulums to a little extent along, before disengaging
and permitting them to swing in the opposite direction. By this means the books k, l,
will to a certainty engage with the hooks k, l, even if the circuit, after having been
closed, he immediately interrupted again. A swinging pendulum, before receiving
its impulses never mounts to the full height from which it has fallen, owing to the
resistance of the air and friction. Accordingly, the two noses of the arms k¹, k, and
1, would not engage again, if the circuit had been interrupted, before an impulse
had been imparted to the pendulums. But by aid of this device they will engage
without fail, the pendulums being always set free at an elevated position.
For working the stopping or catching device, herebefore described, the variable
main current (Ampère current) in many cases may not advantageously be employed,
because the strength of the current varies according to the number of lamps lighted
by the same at a time. With such varying amount of current the device will not
work satisfactory. I therefore, employ the less changeable Volt-circuit, brought into
action by a translator (or switch) which closes the Volt-circuit, even, if but one lamp
be lighted by the main current.
As will be seen in Figure 1 of the drawings, the translator closes the Volt-circuit
between the two posts, a, and b, and in this circuit are included the electro-magnet M,
and a resistance W, which latter serves to reduce as much as possible, the consumption
of current for working the stopping or catching device.
For the translator in this device a difficulty exists owing to the great variability of
the current within which it is included, changing within limits which have never
heretofore been experienced in combination with a translator.
In the drawings I have shown two modifications of translating devices.
In one of these modifications, shown in Figure 1, the translator consists of a pair
of permanent magnets P, Q, suspended by a torsion wire S, and capable of swinging
like the needle of a galvanometer. The main current entering at c, is guided around
said magnet, before passing into the coil R, by means of an S-shaped conductor n nn ;
the magnets thereby are turned as soon as the current enters, so as to make contact
at T which closes the Volt-circuit.
Instead of this translator another modification shown in Figure 4 may be employed.
It consists of an electro-magnet U through which the main current passes as through
the afore described conductor nn. As soon as but one lamp is lighted by the main
currents, the latter will pass through the electro-magnet U, which attracts its
armature V and closes the volt-circuit by the contact T.
The device works in the following manner.
As long as no current passes through the translator and coil R, because there is
no supply of current to the circuit into which the apparatus for measuring the current
is included, the two pendulums of the two clock works will be at rest, being engaged

page_text: with their hooks ¹ and ' into the corresponding hooks k and 1 of the stopping device,
as shown in Figure 1 of the drawings. The moment when the current enters into the
circuit, the translator will close the Volt-circuit into which the stopping device is
included, the electro-magnet accordingly will attract its armature E, the hooks or
noses k, are lifted and disengaged from the hooks and and the pendulums are
set free to swing. One of the pendulums being made to go fast or slow by the action
of the coil R, the two-clock works will not go equal speed and the slightest deviation
will be automatically indicated on the dials of the differential-counter III by means of
the planet-wheel D arranged between the gear of the two clock works. The amount
of current supplied is counted by the amount of deviation indicated.
As soon as the main current is again interrupted, the torsion of the wire S'
Figure 1, or a spring s, Figure 4, will interrupt the volt circuit, whereupon the
electro-magnet M becomes inactive, the spring i pulls the levers E, F, G, into their
former position, as shown in Figure 1 of the drawings, and the elbowed levers k
and with their hooks again catch the hooks of the pendulums, when next they
approach.
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 :-
--
1. In apparatus for measuring electric currents, the combination with two sets of
clock-work of a differential counter automatically indicating the deviations of said
two sets of clock work by means of a planet wheel arranged between and geared by
the two sets of clock-work, substantially as and for the purpose described.
2. In apparatus for measuring electric currents the combination with a clock or
clocks the deviations of which indicate the amount of current supplied, of an
automatic stopping or catching device for the pendulums, serving to catch and hold
the pendulums when no current is supplied and to set them free at an elevated
position, as soon as the current enters, substantially as and for the purpose described.
3. In apparatus for measuring electric currents, the combination with an electro-
magnetic stopping or catching device, of a translator consisting either of a permanent
pair of magnets or an electro magnet and armature, and serving to close the Volt-
circuit into which the catching-device is included, substantially as and for the purpose
set forth.
4. In apparatus for measuring electric currents the application with a translator for
closing the Volt-circuit of the force of torsion, particularly of a torsion wire or
metallic spiral, serving to easily deflect the contact for closing the circuit, as also for
conducting the Volt-current to the contact point, substantially as described.
5. In apparatus for measuring electric currents the combination with a pair of
astatic magnets serving to close the volt-circuit, of an S shaped conductor through
which the main current passes and deflects the inagnets, for the purpose of reducing
the resistance of the conductor.
Dated this 18th day of June 1887.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicant.