Improvements in Interest Calculating Apparatus.
Year: 1892

page_text: Date of Application, 17th Feb., 1892
Complete Specification Left, 1st Nov., 1892-4ccepted, 10th Dec., 1892
PROVISIONAL, SPECIFICATION.
Improvements in Interest Calculating Apparatus.
A communication by GUSTAV MEYER, of No. 2, Obstgasse, Prague, in the
Empire of Austria, Banker.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors 6, Lord Street, Liverpool and 6 Bank Street, Manchester
both in the County of Lancaster and 323 High Holborn in the County of
Middlesex, Civil Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object an apparatus, the employment of which con-
siderably facilitates the calculation of interest on stocks or capital, and renders any
recalculation of the interest unnecessary as the apparatus must always work
correctly, and the handling of the same is so simple that an error cannot arise.
The mode of operation of the apparatus consists in marking on a strip at given
distances apart the figures 1, 2, 3, 4, etcetera, up to 360 or 365, over or under
which are inserted the interest figures of 1 mark calculated out for the various
necessary rates of interest and No. of days from 1 to 360 or 365.
A second strip, which is divided into the saine number of columns as the first
strip by dividing lines like the first strip, runs parallel to such strip that is to the
one which is provided with the figures 1 to 360 or 365 representing the number
of the days, and the interest product at the various rutes of interest for each given
No. of days.
In these columns the 12 months with the days 1 to 30 or 31 are continuously
entered.
If it be now desired to calculate the interest on a given sum, at a certain rate
of interest, from a certain date to another, for instance, from January 11th to
December 20th, the strip provided with the figures 1 to 360 or 365, on which also
the interest figures of 1 mark for each number of days from 1 to 360 or 365 stand
at the various rates of interest, is adjusted with the column in which the figure 1
stands directly under or over the day of the respective month from which the
interest is to be calculated.
Assuming this to be the 11th January, the figure 1 stands directly above or below
the 11th January. Thereupon the two strips are wound up on a drum, preferably
simultaneously, up to the point at which the day is visible at which the interest is
to be reckoned. The number which stands under this day, for instance, in this case,
under the 20th December, gives the number of the days for which interest is to be
reckoned, and the interest figures standing in the same column give direct the
amount of interest on 1 mark for this given number of days at the various
current rates of interest. It is then only necessary to multiply the sum, on which
it is desired to calculate the interest, by the interest figure in question in order to
obtain the interest on the same.
The following apparatus will show how this invention may be carried out:-
A stand is provided, on which are secured two brackets, in the bearings of which
are seated a movable axle and two fixed axles. On the movable axle there is a
drum, divided, by means of a partition, into two parts, one of which is hollow and
contains a roller which is firmly attached to the movable axle. A nut, fitted on
the movable axle, enables its drum, when necessary, to be fixed on the axle.
On one of the fixed axles, hereafter referred to as axle No. 1, two drums are
arranged, which may revolve independently of one another. Each of these drums
is provided with a spur wheel, in which suitable gear wheels on the other fixed
axle, axle No. 2, engage. These gear wheels, which freely revolve on axle No. 2,

page_text: are subject to the action of spiral springs, which are inserted in spring cases, and
the ends of which are, on the one hand, attached to the gear wheels, and, on the
other hand, to the axle No. 2; through the action of the spiral springs, the two
drums on axle No. 1 have a constant tendency to revolve from left to right.
There is a ratchet wheel on the movable axle, which can be stopped by means of
a pawl. A brake block is arranged at a suitable point for stopping the drum on
the movable axle from time to time, and the axle is revolved by means of a
crank.
The hollow drum on the movable axle is provided with a slot, through which the
months' and days' ribbon passes, which has one end attached to the fixed roller on
the movable axle and the other end attached to one of the drums on axle No. 1.
The second part of the drum on the movable axle and the other drum on axle No. 1
carry the ribbon with its corresponding ends stretched out, on which there are
marked the figures 1 to 360 or 365, and beneath them the interest figures for each
of the respective numbers of days, at the desired rate of interest.
-
The mode of working this new apparatus will become immediately apparent by
describing an example
If, for instance, interest at 6 per cent. is to be calculated on a given sum from the
11th January to the 20th December, the nut on the movable axle is first released,
and the drum thereon is fixed by a suitable adjustment of the brake block. Here-
upon, by means of the crank, the movable axle is revolved until the ribbon is wound
through the slot in the drum so far on the fixed roller that the 11th January comes
to a stand exactly over the No. 1 of the other ribbon. The nut is then again
screwed tight against the drum, so that this latter is again firmly attached to the
axle.
1. The drum is then released by a suitable adjustment of the brake block, and, by
revolving its axle by means of the crank, the two ribbons are wound perfectly
evenly on the two equally sized parts of the drum until the 20th December appears
at a suitable point, the ribbons, of course, becoming unwound from the rollers on
axle No. 1 and distending the spiral springs contained in the boxes.
By reading the number standing under the 20th December on the one ribbon,
first the number of days is obtained for which the interest is to be reckoned, and,
from the column in question under this number, the amount of interest at the
desired rate of interest for this given number of days on 1 mark may be read
off. If then the sum to be calculated be multiplied by the interest figures, the
interest will be directly obtained.
· ·By releasing the ratchet wheel and unscrewing the nut, the ribbons are again
wound on the drums by the action of the spiral springs contained in the boxes, and
brought into a suitable position for adjusting the ribbons to allow of other interest
being calculated.
In order. not to have to revolve the crank so frequently, the same may also engage
with the axle of a spur wheel, which engages with a translation device in con-
nection with a small spur wheel arranged on the movable axle of the apparatus.
It is preferable to cover the entire interest-calculating apparatus with a cover.
which is provided, at suitable points, with a slot covered with glass of such a
breadth that only one column or less on the ribbons may be seen through the same,
so that the adjustment of the ribbons to each other, as well as the reading off of
the interest figures, may be done with certainty.
In a modified form of construction, the brake block above referred to is replaced
by a pin, which is screwed into the edge of the drum on the movable axle. The
check nut is also omitted in this method of construction, and the same is replaced
by a double armed. brake lever actuated by means of a spring. One arm of this
brake lever is provided with fine teeth and bears on a wheel which is also provided
.with fine teeth and is attached to the drum on the movable axle, and, in this
manner, connects the parts and the axle. If, on the contrary, pressure be applied
to the knob projecting through the cover, which is usually held raised by means
of a spring, the brake lever is lifted off its toothed wheel. The drum of the

page_text: movable axle is then prevented revolving by the pin striking against the pressure
knob, so that only the inner drum can revolve. In order to obviate the necessity
of continually holding the knob down by hand during the adjustment, the same is
provided with a pin. When the knob is pressed down and turned about 90 degrees,
this pin rests against brackets and thus prevents the knob springing up
unintentionally.
When the apparatus has been adjusted in the manner above described, the knob
is again turned back about 90 degrees; it springs up, the brake lever bears on the
brake wheel, and the two drums are again coupled.
..In the lid of the box, a table may be advantageously inserted, on which the
necessary multiplications may be carried out.
The above described apparatus may also be employed for the calculation of the
interest for several years.
In such case, the dates of two, three, or more years must be marked on the
respective strips, as well as the figures be carried out on the other ribbons up
to 720 (or 730) or 1080 (or 1095), and also naturally the interest for the corre
sponding percentages must be reckoned out and marked thereon.
1000
WM. P. THOMPSON & Co.,
Agents for the Applicant.
WM. P. THOMPSON & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Interest Calculating Apparatus.
A communication by GUSTAV MEYER, of No. 2, Obstgasse, Prague, in the
Empire of Austria, Banker.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.1.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster and 323 High Holborn, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :—
This invention has for its obiect an apparatus, the employment of which
considerably facilitates the calculation of interest on stocks or capital, and renders
any re-calculation of the interest unnecessary as the apparatus must always work
correctly, and the handling of the same is so simple that an error cannot arise.
The mode of operation of the apparatus consists in marking on a strip at given
distances apart the figures 1, 2, 3, 4, etcetera, up to 360 or 365, over or under which
are inserted the interest figures of 1 mark calculated out for the various necessary
rates of interest and No. of days from 1 to 360 or 365.
A second strip, which is divided into the same number of columns as the first
strip by dividing lines like the first strip, runs parallel to such strip, that is, to the
one which is provided with the figures 1 to 360 or 365 representing the number of
the days, and the interest product at the various rates of interest for each given
number of days.
In these columns, the 12 months with the days 1 to 30 or 31 are continuously
entered.
If it be now desired to calculate the interest on a given sum at a certain rate of
interest, from a certain date to another, for instance, from January 11th to
December 20th, the strip provided with the figures 1 to 360 or 365, on which also
the interest figures of 1 mark for each number of days from 1 to 360 or 365 stand
at the various rates of interest, is adjusted with the column in which the figure 1
stands directly under or over the day of the respective month from which the
interest is to be calculated.
Assuming this to be the 11th January, the figure 1 stands directly above or
below the 11th January.. Thereupon the two strips are wound up on a drum,

page_text: preferably simultaneously, up to the point at which the day is visible at which the
interest is to be reckoned. The number which stands under this day, for instance,
in this case, under the 20th December, gives the number of the days for which
interest is to be reckoned, and the interest figures standing in the same column give
direct the amount of interest on 1 mark for this given number of days at the
various current rates of interest. It is then only necessary to multiply the sum, on
which it is desired to calculate the interest, by the interest figure in question in
order to obtain the interest on the same.
This improved apparatus for calculating the interest on stocks and capital may
be the more easily understood by reference being had to the accompanying
drawings, in which :-
Figure 1 is a side view of the apparatus ;
Figure 2 a plan of the same;
Figure 3 a longitudinal section on the line of Figure 2;
Figures 4 and 5 are section and plan respectively of a somewhat modified form
of construction of the interest calculating apparatus.
As shown on the drawings, this new apparatus consists of a stand, A, on which
are secured two brackets B, in the bearings of which are seated a movable axle C
and two fixed axles D and E. On the movable axle C there is a drum J, divided,
by means of a partition F, into two parts G and H, one of which, G, is hollow and
contains a roller K, Figures 2 and 3, which is firmly attached to the movable
axle C. A nut L, fitted on the movable axle C, enables its drum J, when
necessary, to be fixed on the axle C.
•
On one of the fixed axles E, hereafter referred to as axle No. 1, two drums M
and N are arranged, which may revolve independently of one another. Each of
these drums M and N is provided with a spur wheel O and P, in which suitable
gear wheels Q and R, on the other fixed axle, axle No. 2, engage. These gear
wheels Q and R, which freely revolve on axle D, are subject to the action of
spiral springs, which are inserted in spring cases S and T, and the ends of which
are, on the one hand, attached to the gear wheels Q and R, and, on the other
hand, to the fixed axle D; through the action of the spiral springs, the two
drums M and N on axle No. 1 have a constant tendency to revolve from left to
right, as shown by the arrow, Figure 2.
There is a ratchet wheel W on the movable axle C, which can be stopped by
means of
pawl V. A brake block Z is also arranged at a suitable point for
stopping the drum J on the movable axle from time to time, and the axle C is
revolved by means of a crank X.
The hollow drum G on the movable axle is provided with a slot U, through
which the months' and days' ribbon a passes, which has one end attached to the
fixed roller K on the movable axle, and the other end attached to the drum M on
axle No. 1. The second part H of the drum J on the movable axle and the other
drum N on axle No. 1 carry the ribbon b with its corresponding ends stretched
out, on which there are marked the figures 1 to 360 or 365, and beneath them
the interest figures for each of the respective numbers of days, at the desired rate
of interest.
The mode of working this new apparatus will become immediately apparent by
describing an example:-
If, for instance, interest at 6 per cent. is to be calculated on a given sum from
the 11th of January to the 20th of December: with the machine in the position
shown in Figure 2 of the drawing, the nut L on the movable axle is first released,
and the drum 'J thereupon is fixed by a suitable adjustment of the brake block Z.
Hereupon, by means of the crank ✗, the movable axle C is revolved until the
ribbon is wound through the slot U in the drum.G, see Figures 2 and 3, so far
on the fixed roller K that the 11th of January comes to a stand exactly over the
.No. 1 of the other ribbon b. The nut L is then again screwed tight against the
drum J, so that this latter is again. firmly attached to the axle C.
The drum J is then released by a suitable adjustment of the "brake block Z,

page_text: and, by revolving its axle C by means of the crank X, the two ribbons a and b
are wound perfectly evenly on the two parts G and H of equal diameters of the
drum J, until the 20th December appears at a suitable point, the ribbons a and b;
of course, becoming unwound from the rollers M N on axle No. 1 and distending
the spiral springs contained in the boxes S and T.
By reading the number standing under the 20th December on the ribbon b,
first the number of days is obtained for which the interest is to be reckoned, and,
from the column in question under this number, the amount of interest at the
desired rate of interest for this given number of days on 1 mark may be read off.
If then the sum to be calculated be multiplied by the interest figures, the interest
will be directly obtained.
By releasing the ratchet wheel W and unscrewing the nut L, the ribbons a
and b are again wound on the drums M and N by the action of the spiral springs
contained in the boxes S and T and brought into a suitable position for adjusting
the ribbons a and b to allow of other interest being calculated.
also
In order not to have to revolve the crank X so frequently, the same may
engage with the axle g of a spur wheel h, which engages with a translation device
in connection with a small spur wheel K arranged on the movable axle C of the
apparatus, see Figures 4 and 5.
It is preferable to cover the entire interest-calculating apparatus with a cover l,
see Figures 4 and 5, which is provided, at suitable points, with a slot covered
with glass m of such a breadth that only one column or less on the ribbons a
and may be seen through the same, so that the adjustment of the ribbons a
and b to each other, as well as the reading off of the interest figures, may be done
with certainty.
In a modified form of construction, shown in Figures 4 and 5, the brake block Z
above referred to is replaced by a pin n, which is screwed into the edge of the
drum J on the movable axle. The check nut L is also omitted in this method
of construction, and the same is replaced by a double armed brake lever p,
actuated by means of a spring o. One arm of this brake lever p is provided with
fine teeth and bears on a wheel y, which is also provided with fine teeth and is
attached to the drum J on the movable axle, and, in this manner, connects the
drum J with the drum K and the axle C. If, on the contrary, pressure be applied
to the knob, projecting through the cover, which is usually held raised by means
of a spring S, the brake lever p is lifted off its toothed wheel q. The drum J of
the movable axle is then prevented revolving by the pin n striking against the
pressure knob r, so that only the inner drum K can revolve. In order to obviate
the necessity of continually holding the knob, down by hand during the adjust-
ment, the same is provided with a pin v. When the knob r is pressed down and
turned about 90 degrees, this pin v rests against brackets w and thus prevents the
knob r springing up unintentionally.
When the apparatus has been adjusted in the manner above described, the
knob is again turned back about 90 degrees, it springs up, the brake lever p
bears on the brake wheel g, and the two drums J and K are again coupled.
In the lid of the box l, a table y may be advantageously inserted, on which the
necessary multiplications may be carried out.
The above described apparatus may also be employed for the calculation of the
interest for several years.
In such case, the dates of two, three, or more years must be marked on the
respective strips, as well as the figures be carried out on the other ribbons up
to 720 (or 730) or 1080 (or 1095), and also naturally the interest for the corre
sponding percentages must be reckoned out and marked thereon.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. The improvements in interest calculating apparatus, which consist in the

page_text: arrangement of two equally subdivided ribbons (a and b) placed side by side and
marked as specified, the ends of which are attached to independent rollers (M
and N) freely revoluble and acting under spring pressure, whilst the other end
of one (b) of the ribbons is attached to the part H of a roller (J) freely revoluble
or fixable on an axle, whilst the other ribben (a) is attached to a roller (K) in 5
the part (G) of J and passes through a slot (U), so that the ribbons may be
adjusted to one another on J, being released and turned by suitable means, or both
ribbons may be simultaneously wound on J by turning the axle (C) when J is
fixed, substantially as specified.
2. The general arrangement and construction of the improved interest calculating
apparatus substantially as hereinbefore described and shown.
Dated this 31st day of October 1892.
WM. P. THOMPSON & Co.,
Agents for the Applicant.