IMPROVEMENTS. IN CHRONOGRAPHS OR APPARATUS FOR MARKING AND RECORDING MEASURED PERIODS OF TIME
Year: 1881

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in.
the County of Middlesex, Gentleman, for an Invention of "IMPROVEMENTS.
IN CHRONOGRAPHS OR APPARATUS FOR MARKING AND RECORDING MEASURED
PERIODS OF TIME." A communication from abroad by Alvin L. Strasburger,
of Chaux-de-Fonds in the Republic of France.
(Void by reason of the Patentee having neglected to file a Specification in
pursuance of the conditions of the Letters Patent.)
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 28th January 1881.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN CHRONOGRAPHS OR APPARATUS FOR MARKING.
AND RECORDING MEASURED PERIODS OF TIME." A communication from abroad.
by Alvin L. Strasburger, of Chaux-de-Fonds, in the Republic of France.
This Invention relates to chronographs or apparatus employed in what are
known as stop watches for marking and recording measured periods of time, and
it consists in certain improvements hereinafter described in the construction and
arrangement of the parts, whereby it is rendered possible to set the hand of the
chronograph in motion or stop instantaneously at any given point on the dial,
or return it to zero at will with great facility.
In carrying out this Invention a toothed wheel is fixed on a prolongation of the
spindle of the hand indicating the seconds on the watch face, and this wheel
imparts motion to a corresponding wheel of the same diameter, turning on a pin
or stud, which is carried by an oscillating arm hereinafter described. The latter
wheel is provided with a sleeve carrying a hand indicating seconds and portions
of seconds, for example, on the dial of the chronograph. The arm hereinbefore
referred to is capable of oscillating on a pin fixed to the watch plate, and a spring
is caused to press against one side of this arm in such a manner as to tend to throw
[Price 2d1

page_text: the wheel connected to the chronograph hand out of gear with the wheel on the
spindle of the seconds hand, whilst another and weaker spring on the opposite
side of the arm tends to bring the said wheels into gear with each other.
A lever pivotted on a fixed pin is provided on its under side with a projection
which is capable of bearing against the first of the two springs hereinbefore
described, and carries at one extremity a nose or angular projection which is
capable of acting on a heart shaped cam turning with the hand of the chronograph.
The opposite extremity of this lever projects slightly at one side of the watch case
The wheel
so as to enable it to be moved by the finger, as hereinafter described.
carrying the hand of the chronograph is steadied and retained on the pin on which
it turns by means of a flat spring attached to the watch plate, slotted or forked at
one extremity so as to embrace the sleeve on the said wheel above the cam herein-
before described, and another spring is employed provided with a pin near one
extremity which engages alternately with opposite sides of the lever for the purpose
of steadying the said lever and retaining it in position when shifted, as hereinafter
described.
In order to set the hand of the chronograph in motion the lever must be moved
by pressing on its protruding extremity with the finger until the projection on its
underside comes in contact with and compresses the spring which bears against
the oscillating arm, and tends to throw the wheels out of gear, as hereinbefore
described, whereupon the weaker spring on the opposite side of the arm is enabled
to move the said arm and cause the wheel connected with the chronograph hand
to engage with the wheel on the spindle of the seconds hand.
The chronograph hand then rotates in unison with the seconds hand of the
watch, and indicates the seconds and fractions on the dial of the chronograph. In
order to stop the chronograph hand at any desired point it is simply necessary to
shift the lever for a certain extent in the opposite direction so as to relax the spring
which was previously compressed, as hereinbefore described, and allow the said
spring to act upon the oscillating arm and move the wheels out of gear again,
thereby arresting the motion of the chronograph hand. When the parts are in
this position the hand may be caused to resume its motion without returning to
zero by simply returning the lever to the position in which the wheels are brought
into gear. If, on the contrary, it is desired to cause the chronograph hand to
return to zero the lever must be shifted still further in the same direction as when
moving to stop the hand, whereupon the angular projection with which it is
provided at one extremity, as hereinbefore described, comes in contact with the
heart shaped cam connected to the hand of the chronograph, and presses against
this cam so as to cause it to turn rapidly until its smallest radius is brought opposite
the said projection, the hand being connected to the cam in such a manner that
when the smallest radius of the cam is opposite the projection on the lever the
hand is caused to move to zero simultaneously with this motion of the cam.