AN IMPROVED CHRONOGRAPH OR INSTRUMENT FOR MEASURING ACCURATELY SHORT INTERVALS OF TIME
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "AN IMPROVED
CHRONOGRAPH OR INSTRUMENT FOR MEASURING ACCURATELY SHORT
INTERVALS OF TIME." A communication from abroad by Hermann Josephi
Eisen, of Geneva, Switzerland.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 6th January 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "AN IMPROVED CHRONOGRAPH OR INSTRUMENT FOR
MEASURING ACCURATELY SHORT INTERVALS OF TIME." [A communication from
abroad by Hermann Joseph Eisen, of Geneva, Switzerland.]
This Invention relates to a chronograph or instrument for measuring accurately
short intervals of time; and the improvement consists chiefly in the mechanism
for actuating double hands resembling "split seconds which may be arrested
independently of one another, or made to move together at will.
Figures 1, 2, 3, of the accompanying Drawings show in different positions the
mechanism of an ordinary chronograph with a single seconds hand, and the other
Figures show the improvement of this Invention; Figure 4 shows the dial and the
mechanism of this Invention for actuating the double or split seconds hand,
the two hands coinciding and working together in this Figure; Figure 5 represents
similar views, the one hand being arrested independently of the other; Figures
6, 7, and 8, represent details. The same letters of reference are employed in all the
Figures to designate the same parts. a is the star wheel in the ordinary single
hand chronograph, one half of its thickness (that which is uppermost in the
Drawing) has 9 teeth, while the other or lower half has three deep notches, opposite
each of which there are two teeth of the upper side. The star wheel is moved to
the extent of one tooth every time the stud b is pressed in. d, e, are two heart
wheels (to which the improvement of this Invention is applied, as hereafter
described), each fixed on a hollow arbor or pipe o carrying a hand f fitting with
slight friction upon the arbor of a pinion of the wheel work.
D....11

page_text: Figure 3 shows the normal position of the parts before setting the mechanism in
motion by pressing stud b; Figure 1 shows the mechanism in motion. On again
pressing stud b the motion of the hand is arrested, as in Figure 2. By again
pressing the stud the hand is returned to zero. Whenever the part g, g', is pushed
back by the star wheel a, the heart wheels are free; but when it falls into a deep
notch, as in Figure 3, the friction rollers on its two arms press against said heart
wheels and cause the hand to fly back to zero. The lever has a pin at one end
which arrests the balance when the other end is raised by a tooth of the star
wheel. Every time lever h falls into a deep notch of the star wheel the balance is
free to vibrate.
The Invention consists in the combination of mechanism for actuating double stop
seconds hands which may be made to coincide at will, as hereafter described. In
Figure 4 there are two second hands f, f¹, of which the second is mounted on a
pipe fixed to a steel plate i. Beneath the heart wheel d is a small spring k which
presses it up to the plato i, see Figure 6. To enable all kinds of observations to be
made the mechanism is so arranged that the extra stop seconds hand f¹ can be
arrested at will independently of the other. For this purpose the heart wheel ‹l,
instead of being single, as in Figures 1, 2, 3, is made double, as in Figure 7, but in
one piece, the smaller heart being that for the seconds hand f'. Beneath the
plate above mentioned is a steel roller m which is free to travel around the small
heart wheel 7. When the two hands f, f¹, move together the roller rests in the
recess of the heart wheel, but if the plate i be prevented from turning with the
double heart the roller will escape from the recess and the heart will turn together
with the hand f, while f¹ will remain where it was arrested by pressing against
the plate i (see Figure 5, which shows plate i and hand f stopped). Immediately
the plate is released from pressure, the roller m attached thereto presses against
and travels around the heart wheel until it enters the recess, whereupon both
hands will coincide as at starting. Each time stud p is pressed the star wheel q
advanced one tooth by the lever p¹, said star wheel having 8 teeth, 4 of which are
made deeper than the rest; in the Drawing the detent r is shown as dropped into
one of the deep teeth, so that its end s bears against plate i to arrest it. On
pressing the stud a second time the wheel q is again advanced; but the next tooth
being less deep prevents the detent arm pressing on plate i, which being free is
rotated by its roller m travelling round heart l, carrying with it hand f' until the
two hands coincide. Thus the plate i is stopped the first time the stud p is.
pressed and released at the second pressure. The stopping and starting of the
movement as well as the action of the heart e of the minute hand are the same as
in the arrangement shown in Figures 1, 2, 3.
Hitherto the dial n has been graduated only to 10 minutes, but I prefer to
divide it into 30 minutes, which necessitates only a simple modification of the
train which needs no description.
This improved chronograph may be employed either alone or combined with any
kind of watch.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
6th July 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "AN IMPROVED CHRONOGRAPH OR INSTRUMENT FOR
MEASURING ACCURATELY SHORT INTERVALS OF TIME." A communication from
abroad by Hermann Joseph Eisen, of Geneva, Switzerland.
This Invention relates to an improved chronograph or instrument for measuring
accurately short intervals of time, and the improvement consists chiefly in the
mechanism for actuating double hands resembling "split seconds" which may be
arrested independently of one another, or made to move together at will.
In order that the Invention may be more readily understood I will proceed to
describe the same, by way of example, with reference to the accompanying
Drawings, in which Figures 1, 2, 3, show face and interior views with the
mechanism in different positions of an ordinary chronograph with a single seconds
hand, the other Figures show the improvement of this Invention; Figure 4 shows
the dial and the mechanism of this Invention for actuating the double or split
seconds hand, the two hands coinciding and working together in this Figure;
Figure 5 represents similar views, the one hand being arrested independently of
the other; Figures 6, 7, and 8, represent details. The same letters of reference are
employed in all the Figures to designate the same parts.
a is the star wheel in the ordinary single hand chronograph, one half of its
thickness (that which is uppermost in the Drawing) has nine teeth, while the
other or lower half has only six teeth and three deep notches, opposite each of
which there are two teeth of the upper side. The star wheel is moved to the
extent of one tooth every time the stud b is pressed in, so that a fresh tooth
engages each time with spring c. d, e, are two heart wheels (to which the
improvement of this Invention is applied, as hereafter described), each fixed on a
hollow arbor or pipe o carrying a hand f fitting with slight friction upon the arbor
of a pinion of the wheel work.
Figure 3 shows the normal position of the parts before setting the mechanism in
motion by pressing stud b; Figure 1 shows the mechanism in motion. On again
pressing stud b the motion of the hand is arrested, as in Figure 2. By again
pressing the stud the hand f is returned to zero. Whenever the part g, g',
is pushed back by the star wheel a, the heart wheels are free; but when it falls into
a deep notch, as in Figure 3, the friction rollers on its two arms press against said
heart wheels and cause the hand to fly back to zero. The lever h has a pin at one
end which arrests the balance when the other end is raised by a tooth of the star
wheel. Every time lever h falls into a deep notch of the star wheel the balance is
free to vibrate.
The Invention consists in the combination of mechanism for actuating double stop
seconds-hands which may at will be arrested independently of one another, like what
are known as "split seconds," or made to coincide and move together, as hereafter
described. In Figure 4 there are two seconds hands f, f³, of which the second one
is mounted on a pipe fixed to a steel plate i. Beneath the heart wheel d is a small
spring k which presses it up to the plate i, see Figure 6. To enable all kinds of
observations to be made the mechanism is so arranged that the extra stop seconds
hand f¹ can be arrested at will independently of the other. For this purpose the
heart wheel d, instead of being single, as in Figures 1, 2, 3, is made double, as in
Figure 7, but in one piece, the smaller heart being that for the seconds hand f¹.
Beneath the plate i above mentioned is a steel roller m which is free to travel

page_text: around the small heart wheel 1. When the two hands f, f', move together the
roller rests in the recess of the heart wheel, but if the plate i be prevented from
turning with the double beart the roller will escape from the recess and the heart
will turn together with the hand f, while f¹ will remain where it was arrested by
pressing against the plate i (see Figure 5 which shows plate i and hand f stopped).
Immediately the plate is released from pressure the roller m attached thereto
presses against and travels around the heart wheel until it enters the recess,
whereupon both hands will coincide as at starting. Each time stud p is pressed
the star wheel q is advanced one tooth by the lever p', said star wheel having eight
teeth, four of which are made deeper than the rest; in the Drawing the detent r is
shown as dropped into one of the deep teeth, so that its end s bears against plate i
to arrest it. On pressing the stud a second time the wheel q is again advanced,
but the next tooth being less deep prevents the detent arm pressing on plate i,
which being free, is rotated by its roller m travelling round heart l, carrying with
it hand f¹ until the two hands coincide. Thus the plate i is stopped the first time
the stud p is pressed and released at the second pressure. The stopping and
starting of the movement, as well as the action of the heart e of the minute hand,
are the same as in the arrangement shown in Figures 1, 2, 3.
Hitherto the dial n has been graduated only to 10 minutes, but I prefer to
divide it into 30 minutes, which necessitates only a simple modification of the
train, which needs no description.
This improved chronograph may be employed either alone or combined with any
kind of watch. The form and arrangement of the details of the various parts of
the mechanism may also be varied without departing from the Invention.
Having described the nature of the said Invention, and the manner of performing
the same,
declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is,―
1st. In a chronograph, the combination of mechanism for actuating double
hands, whereby they may be arrested independently, or made to coincide and move
together, substantially as described and shown in the Drawings.
2nd. The double heart wheel provided with a hollow arbor or pipe, upon which
a hand is fixed, as shown and described for the purpose specified.
3rd. The combination of the extra hand and the steel disc with the double
heart d, l, and the spring k, arranged and operating substantially as shown and
described for the purpose specified.
4th. The combination of the double heart d, l, and roller m, as shown and
described for the purpose specified.
5th. The star wheel 7 and detent constructed and combined to operate in the
manner described for arresting and releasing disc i, as shown and described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Sixth day of July, A.D. 1881.