Year: 1886

page_text: We, JOHANNES DURRSTEIN and FRIEDRICH DURRSTEIN both of the firm of
Durrstein & Co. of Dresden, in the Empire of Germany, Merchants do hereby
declare the nature of this invention to be as follows:-
Our invention for improvements in watches and other time pieces relates to that
class of time piece in which the time is denoted by numerals which become visible
through slots in the dial or face; and has for its object to provide more efficient
means for driving the discs on which are placed the numerals for denoting
the time.
In a watch constructed according to our invention, the motive power for driving
the above mentioned discs is derived from a separate spring provided in addition
to that for driving the ordinary watch mechanism, and is transmitted through
suitable intermediate gearing to a pinion secured on a lever arm mounted so as to
be capable of rotation about the axis of the said pinion. The end of the lever arm
normally bears against a tooth on a star wheel so that the lever arm is prevented
from being rotated by the aforesaid spring. The star wheel is driven by the
ordinary watch mechanism at such a speed that the lever arm is allowed to escape
once in every minute, it then making a single revolution about its axis and being
then stopped by the next tooth of the star wheel until it is again released. The
hereinbefore mentioned intermediate gearing is thus rotated and actuates the train
of wheels operating the discs for denoting the time.. One of these discs denotes
the minute intervals, another the ten-minute intervals and the third the hour
intervals, the two latter being driven from the former as in ordinary counting or
recording mechanism. One of the intermediate wheels of the train driving the
said discs is mounted on the end of a lever which can be operated by a rod to draw
this wheel out of gear with its, driver so as to allow the watch to be set to the
correct or other desired time.

page_text: We, JOHANNES DURRSTEIN and FRIEDRICH DURRSTEIN both of the firm of
Durrstein & Co. of Dresden, in the Empire of Germany, Merchants, 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:-
Our invention for improvements in watches and other timepieces relates to that
class of timepiece in which the time is denoted by numerals which become visible
through slots in the dial or face; and has for its object to provide more efficient
means for driving the discs on which are placed the numerals for denoting
the time.
In a watch constructed according to our invention, the motive power for driving
the above-mentioned discs is derived from a separate spring provided in addition
to that for driving the ordinary watch mechanism and is transmitted through
suitable intermediate gearing to a pinion secured on a lever arm mounted so as to
be capable of rotation about the axis of the said pinion. The end of the lever arm
normally bears against a tooth on a star wheel so that the lever arm is prevented
from being rotated by the aforesaid spring. The star wheel is driven by the
ordinary watch mechanism at such a speed that the lever arm is allowed to escape
once in every minute, it then making a single revolution about its axis and being
then stopped by the next tooth of the star wheel until it is again released. The
bereinbefore mentioned intermediate gearing is thus rotated and actuates the train
of wheels operating the discs for denoting the time. One of these discs denotes
the minute intervals, another the ten-minute intervals and the third the hour
intervals; the two latter being driven from the former as in ordinary counting or
recording mechanism. One of the intermediate wheels of the train driving the
said discs is mounted on the end of a lever which can be operated by a rod to draw
this wheel out of gear with its driver so as to allow the timepiece to be set to the
correct or other desired time.
In the accompanying sheet of drawings,
Fig. 1 is a back elevation to an enlarged scale of a watch constructed according
to this invention.
Fig. 2 is a side elevation and
Fig. 3 a front elevation with the dial removed of the same.
The ordinary watch mechanism is driven by the spring in the box a in the
ordinary manner as clearly shown in fig. 1. The time is indicated by numerals on
the discs p, 8, v; the disc p showing the minute intervals, the disc s the ten-minute
intervals, and the disc v the hour-intervals. The numerals are visible at the front
of the watch through slots or openings in the dial plate e³. The disc s is driven
from the disc p by means of the projection q so that the disc 8 is moved through
one-sixth of a revolution for every revolution of the disc p. In a similar manner
the disc vis driven from the disc 8 by means of the projection t, it making one-
twelfth of a revolution for every revolution of the disc 8.

page_text: The discs p, 8, v, are driven by the spring in the box b which transmits its power
through a pinion to the wheel c gearing with a pinion e on the axle of the wheel d
gearing with a pinion f on the axis of the lever g. The spring in the box 6 thus
tends to rotate the lever g. Normally however the end of the lever. bears against
a tooth on a star wheel connected to a pinion h on the axle of a wheel k driven
by the ordinary clockwork mechanism. The wheel is thus driven from the
ordinary clockwork mechanism, the gearing being so arranged that the wheel Z
makes six revolutions per hour and-it having ten teeth-consequently the lever g
escapes sixty times in the hour or once every minute. The lever g thus makes a
complete rotation every minute and is stopped after each rotation by the next
tooth of the wheel to that from which it has just escaped.
A wheel m is mounted on the axle of the pinion e and wheel d, the wheel m
being on the opposite side of the back plate e'. The wheel m gears with a wheel n
mounted on a stud on the lever z. The wheel n gears with a wheel o secured to
the axle of the disc p. It will thus be seen that every time the lever g makes a
complete rotation, the disc p is driven through one-tenth of a revolution by means
of the gearing f, d, m, n, o. The spring serves to prevent any shaking of the
disc
p.
In order that the discs p, 8, v may be set to indicate the correct or other desired
time, the lever z is mounted so that it can be rotated about the axis of the wheel o
from the outside of the watch case by means of the pin w, the two arm lever x and
pin y to raise the wheel n out of gear with the wheel m. The wheel m gears with
a wheel connected to the winding ring by means of which the discs can be set to
denote the desired time when the wheels m n are not in gear. The wheel n is
normally kept in gear with the wheel m by the spring i which tends to bring the
bar into the required position.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed, we declare that what
we claim is:-
In timepieces of that class in which the time is denoted by numerals which
become visible through slots in the dial or face, the construction and arrangement
of the lever whose motion is controlled by the star wheel driven from the
ordinary clockwork mechanism and which controls the gearing f, d, m, n, o driving
the discs for indicating the time and driven by a separate spring in the box
substantially as described with reference to the drawings.
·
T
WHEATLEY & MACKENZIE,
Agents for the Applicants,
156, Strand, London, W.C.