Improvements in Electric Meters.
Year: 1893

page_text: Date of Application, 28th Nov., 1893
Complete Specification Left, 27th Aug., 1894-Accepted, 13th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in Electric Meters.
I, HERMANN ARON, of 6 Lützowstrasse Berlin, Kingdom of Prussia, German
Empire, Professor, and Doctor of Philosophy, do hereby declare the nature of
this invention to be as follows:-
This invention relates to an improvement in apparatus for measuring electric
currents, and its object is more particularly to prevent false indications of the
differential counting apparatus of electrical energy.
In apparatus of that class, which measure, count or record the deviations of two
arrangements of clock-work or wheel-trains, it sometimes happens that one of the
two stops, while the other clock-work or wheel-train continues to move. In such
cases, the axis of the differential counter, which normally rotates with a speed
proportional to the expense of electrical energy in the working line, will run
forward or backward with great speed, whereby not only the counting apparatus is
prevented from recording but the records already obtained up to the moment at
which one of the works stops, become altered and false. My invention accordingly
consists in the adoption of suitable means which, as soon as one of the arrangements
of clock-work or train of wheels stops, will prevent the other clock-work or wheel-
train from working. As soon as both are stopped, the apparatus, of course, ceases'
to record but the records already obtained remain unaltered.
The means which I employ to attain this object are based upon the following"
principle―
The maximum of deviations of the two clocks being limited by the capacity of
the apparatus and as any overstraining by the current will cause the lead connections
to melt, the excess of deviations, caused by the stopping of one of the works, may
be utilised to stop the other clock-work likewise. It will be easily understood
that, if one clock-work stops, the deviations in the speed of the two clock-works
will reach their maximum amount.
The mechanical means which I prefer to employ, are applied to my former
apparatus described in the Specification No. 8856 of 1887 in which the deviations
of the two arrangements of clock-work are registered through the agency of a
planet wheel in gear with two crown wheels which receive motion independently
of each other, respectively by the two clock-works. The said planet wheel remains
stationary as long as the two crown wheels turn with exactly the same speed, and
it turns around the common shaft as soon as the speed of the two crown wheels is
different.
According to my present invention, I arrange a stop in the path of the said
planet-wheel, which stop will prevent the said planet-wheel from rotating, if not
removed. During the normal state, that is, when the two crown wheels are turning
at equal speed or with such deviations only which do not exceed the maximum,
the said stop will be regularly lifted out of the path of the planet-wheel, and the
latter may perform its recording motion. But if the said planet-wheel rotates
more quickly, it will reach the stop before the latter becomes lifted and, accordingly,
the planet-wheel is stopped and thereby causes the other crown-wheel to be stopped
likewise. Now, as the said planet-wheel will reach its maximum speed as soon as
one of the crown-wheels and clock-work accidentally stop, the stoppage of the
other crown wheel and clock-work is automatically obtained through the agency of
the planet wheel.

page_text: The stop which extends into the path of the planet-wheel is lifted out of the
said path by a suitable device connected to one of the said crown-wheels or to a
separate wheel in gear with one of the crown-wheels.
Dated this 27th day of November 1893.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
Improvements in Electric Meters.
I, HERMANN ARON of 6 Lützowstrasse, Berlin, Kingdom of Prussia, German
Empire, Professor and Doctor of Philosophy, 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 an improved apparatus for measuring electric currents
and the object of my said invention is particularly to prevent false indications of
the differential counting apparatus of electrical energy.
In apparatus of that class which measure, count or record the deviations of two
clock-works or wheel-trains caused by the current to be measured, it sometimes
happens that one of the two stops from some cause, while the other clock-work or
wheel-train continues to move. In such cases the axis of the differential counter,
which, normally, rotates with a speed equal to the difference of speed of the two
clock-works, which differential speed corresponds to the expense of electrical energy
in the working line, will run forward or backward with great speed, whereby not
only is the counting apparatus prevented from further recording the consumption
of current but the records already obtained up to the moment when one of the
clocks did stop, become altered and false. My invention, accordingly, consists in
providing suitable means which, as soon as one of the works stops, prevent the
other clock-work or wheel-train also from working. As soon as both clock-works
or wheel-trains are stopped, the apparatus, of course, ceases to record the expense
of current, but the records already obtained remain unaltered.
The means which I employ to attain this object are based upon the following
principle―
Owing to the fact that the maximum amount of deviations between the two
clock-works or wheel-trains is limited by the capacity of the apparatus and that
any excess over said capacity is prevented by the lead-connections which melt
under an excess of current, any excess over such normal maximum amount of
deviations of the instrument may be utilised to stop the clock-works. Such excess
over the normal maximum amount of deviations will occur as soon as one of the
two clock-works or wheel-trains happens to stop, because in such case the difference
of speed of the two works will be greatest.
The following example will help to explain the theory of my invention when
employed in combination with apparatus of the kind described in my previous
Patent No. 8856 of 1887.
Suppose an apparatus of that kind to be strained to the utmost of its capacity,
the deviation of the two clock-works caused by the current to be measured will be
from 800 to 1000 oscillations of the pendulum per hour, the normal number of
oscillations being 7200 oscillations per hour. Now, as the planet-wheel of the
differential work of the apparatus turus with a speed equal to the deviation of the
two clock-works, and as the lead-connections with the line melt if the apparatus is
overstrained by the double amount of its capacity, the said planet-wheel, if the
apparatus be overstrained to the utmost, will turn with a speed corresponding to
twice 1000, i.e. 2000 oscillations per hour. But if one of the clocks or wheel-
trains happens to stop, the difference of speed between them will be 7200 – 0,
-

page_text: excess
4.e. 7200 oscillations; accordingly, the planet-wheel will run with an
speed of more than 3 times as compared with that of the maximum amount of
overstraining.
While the planet-wheel, as has been stated before, rotates with a speed corre-
sponding to the difference of speed between the two crown-wheels, each of the
latter two wheels rotates with a speed corresponding to the number of oscillations
of the pendulum of the clock, which actuates the said crown-wheel. The speed of
the crown-wheels, accordingly, is by far greater, than that of the planet-wheel. If
the two clock-works are turning with equal speed, the crown-wheel remains
stationary, and in this case the difference of speed between the crown-wheels and
the planet-wheel is a maximum. But if one of the crown-wheels stops, the planet-
wheel turns with the same speed, as the crown-wheel which continues to turn, and
the difference is a minimum.
The mechanical means which I provide, according to my present invention, for
the purpose of automatically stopping the other crown-wheel, if one of the crown-
wheels accidentally ceases to turn, consist, principally, in arranging a stop in the
path of the axis of the planet-wheel, which stop prevents the said planet-wheel
from moving on, if the said stop. be not removed or lifted before the axis of the
planet-wheel actually comes to strike it. During the normal state, i.e. when the
two crown-wheels are turning with equal speed, or with such deviations only, which
do not exceed the maximum of deviations, the said stop will be regularly lifted out
of the path of the planet-wheel and the latter may regularly perform its recording
operation. But if the said planet-wheel runs fast, it will reach the said stop before
the latter becomes lifted and, accordingly, the planet-wheel is stopped and thereby
causes the other crown-wheel to be stopped likewise. As has been stated before,
the planet-wheel will reach its maximum of speed as soon as one of the crown-
wheels (or its driving clock-work) accidentally stops; it will be readily under-
stood, then, that by the stoppage of one clock-work or crown-wheel, the other
clock-work will be equally and automatically stopped through the agency of the
planet-wheel.
In the accompanying drawings two modifications are illustrated by which the
planet-wheel, when running fast, is stopped and the said stop lifted out of the path
of the said planet-wheel during the regular working of the instrument.
One of the two modifications is represented in Figure 1, a, is the shaft of the
finger of the differential-counter; on the said shaft the two crown-wheels A are
loosely mounted (one of which only is indicated by dotted lines) and on the same
shaft a the axis cell of the planet-wheel 6 is fixed to impart motion to the said
shaft ay whenever the said planet-wheel turns. A counter-weight d serves to balance
the weight of the planet-wheel b. A toothed wheel e, which receives rotary motion
through the medium of one of the two crown-wheels, or by gearing directly with
one of them, carries a laterally projecting pin or stud f, which, as the said wheel e turos,
will strike in regular intervals against an arm h" of an elbow-lever " pivoted as
at g. The said lever-arm being struck, the other arm ', will be lifted to allow
the pawl i, to descend so far as to support the lever-arm h', as indicated in
Figure 1. The said pawl i, has formed on its side an inclined surface k, against
which the outer ends of the shaft c', c¹¹ will strike during the rotation of the planet-
wheel b. The pawl i accordingly, will be lifted and the lever-arın h¹ will descend
till the other arm " bears against the stop l. The lever-arm h¹ carries a laterally
projecting pin m, extending into the path of the axis c', c", as long as the pin f of
the wheele has not lifted the lever into the position shown in Figure 1. The
proportion between the driving crown-wheel and the driven wheel e of course must
be so calculated, that up to the maximum speed of the planet-wheel b, i.e., up to
the maximum load or capacity of the instrument, the elbow-lever h', " will be
regularly lifted out of the path of the planet-wheel, before the latter reaches the
stop m. But as soon as the planet-wheel turns faster than its normal maximal
speed, it will strike against the said pin before it becomes lifted, as described, and
by striking against the stop m, the planet-wheel will be stopped and with it the

page_text: other crown-wheel, which had been moving on, while the first crown-wheel had
been stopped by some other cause. It will be understood, then, that, as soon as one
of the two clock-works or wheel-trains belonging to the instrument, happens to stop
its corresponding crown-wheel driven by the clock-work will equally stop and by so
doing it will cause the planet-wheel to travel with considerable speed around the
shaft a, till its shaft c', or c", strikes against the stop m projecting into its path of
motion. And it will further be understood, that, if one of the two crown-wheels
is stopped and the planet-wheel 6 be prevented from rotating around the shaft a,
the said planet-wheel, being in gear with both crown-wheels and loose ou its
shaft c', will stop the other crown-wheel, and consequently the other clock-work.
The records of delivered current obtained up to the time when one of the two
clock-works accidentally stopped, remain perfectly intact, as the planet-wheel b,
driving the axis of the recording finger, is stopped, as described. If the said
planet-wheel be allowed to travel fast, as described on the stoppage of one of the
crown-wheels, the recording finger would speed on and not only produce an entirely
false record of current delivered, but also cause the loss of the true record up to
that time when the disorder began.
The device described need only be applied to one of the two crown-wheels,
because, if the axis a, should turn in the reverse direction, the shaft c¹ c¹¹ would
equally strike against the surface k, or the pin m, and become stopped. While
the pin m, is being lifted, the surface k, on the pawl i, keeps its lowest position, and
if k has been raised to allow the shaft c¹, c¹¹, to pass, the pin m, is down to lock the
passage. The operation of the device, as described, is not only useful for stopping
the motion of the whole instrument when one of the two clock-works accidentally
stops, but also if the subscriber tries to force the recording mechanism in the
reverse direction, for the purpose of obtaining a false indication.
The other modification of my invention to obtain the same purpose is illustrated
by Figures 2, 3 and 4 Figure 2, being a plan of the device for stopping motion when
one of the two clock-works happens to stop, Figures 3 and 4 being detail views of
parts of the mechanism.
a
is the shaft on which the two crown-wheels A A' are loosely mounted, 6 the
planet-wheel in gear with both crown-wheels and driving the same. From the said
shaft, a, a spur-wheel receives motion, either directly, or by suitable gearing as
shown in Figures 2 and 3, and the said spur-wheel has but a comparatively small
number of indentations. On the circumference of said wheel q, two levers r¹ and r
have a sliding motion, each of said levers being mounted on an axis which carries
a lever or cam s¹ and $11. The two levers 7, 71, are so arranged relatively to each
other, that, as one of the said levers rests on the top of a tooth of wheel 9, the
other lever engages with an indentation of the same wheel, as clearly shown in
Figure 3. Each of the two crown-wheels A A¹ carries a number of laterally
projecting pins u, Figure 4, and above each crown-wheel a pivoted arm tt" is
provided, carrying a downward projecting pin n. If the lever r, as shown, rests on
the top of a tooth of wheel q, its corresponding lever s lifts the arm t¹ so far as to
disengage the pin n from the pins u of the crown-wheel A, and, further, to engage
the forward end of said lever with the upper arm V' of an elbow-lever v', w', as
shown in Figure 4. The said arm t¹ is kept in its raised position by the lever rl gl
till one of the pins u of the crown-wheel A, comes to strike against the lever arm w
thereby disengaging the arm from the said arm t¹ and leaving t¹ free to fall if
the supporting lever s¹ has been withdrawn, that is, when the lever r has been
engaged into a notch of wheel q. The play of levers " and " on wheel A¹ is the
same as that of the corresponding arm of the other crown-wheel A, the said
arm being equally under control of an elbow lever v¹ wo¹.
The essential feature of this modification, as before described, is this, that each
of the two driving crown-wheels meets, at determined intervals, an obstacle in its
path, which obstacle or stop is being removed in proper time through the agency
of the axis a of the differential counter, if both clock-works or wheel-trains are
going. The proportion between the two wheels a and 9, as also the number of

page_text: notches of the wheel 9 and of pins u on the crown-wheels A A¹ must be so
calculated that the planet-wheel b, and, accordingly, the two crown-wheels are
stopped only when the difference of speed between the two crown-wheels has
reached an amount exceeding by far the amount of the normal maximuin of
deviations.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is-
1. In apparatus for measuring or recording electric currents by recording the
deviations of two clock-works or wheel-trains, a device for automatically stopping
one of the two works as soon as the other clock-work or wheel-train happens to
stop, consisting in a stop or obstacle provided in the path of an arm or arms
carried by the axis of the differential-counter, said stop or obstacle being removed or
lifted out of the path of the said arm or arms before they reach the same, as long
as the difference of speed between the two clock-works or wheel trains does not
exceed by far the maximum amount of normal deviatious substantially as and for
the purpose set forth.
2. In apparatus for measuring or recording electric currents by recording the
deviations of clock-works or wheel-trains, a device for automatically stopping one
of the two works as soon as the other clock-work or wheel-train happens to stop,
consisting in the combination, with two crown-wheels, each driven by one of the
said two clock-works or wheel-trains, and a planet-wheel in gear with both of said
crown-wheels and fixed on the axis of the differential counter, of a pivoted elbow-
lever carrying a pin or stop m, a pawl i carrying an inclined surface k and
suppporting said lever h', ", when raised, and a wheel e with a projecting pin f
striking the said lever ¹¹¹, at determined intervals, substantially as and for the
purpose set forth.
3. In apparatus for measuring or recording electric currents by recording the
deviations of clock-works or wheel-trains, a device for automatically stopping one
of the two works as soon as the other clock-work or wheel-train happens to stop,
consisting of a stop or obstacle provided to stop the motion of each of the two crown-
wheels, and of means, substantially as described, for removing said stops or obstacles
at the proper time, as long as the difference of speed between the two clock-works
or wheel-trains does not by far exceed the maximum amount of normal deviations,
substantially as and for the purpose set forth.
4. In apparatus for measuring or recording electric currents by recording the
deviations of clock-works or wheel-trains, a device for automatically stopping one
of the two works as soon as the other clock-work or wheel-train happens to stop,
consisting of two crown-wheels, each connected to one of the said clock-works or
wheel-trains and a planet-wheel in gear with both of said crown-wheels and fixed
on the axis of the differential counter, in combination with a notched or spur-wheel
receiving motion by the shaft of the differential counter, two levers alternately
engaging into the notches of said spur-wheel, a lever-arm or cam carried by the axis
of each of said sliding levers, a pawl and pin under control of said levers and cams,
and means, substantially as described, for retaining the said pawl in its raised position
and out of engagement with the pins projecting from the crown-wheels, substantially
as and for the purpose set forth.
ليكم
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.