AN IMPROVEMENT IN THE CONSTRUCTION OF WATCHES
Year: 1879

page_text: LETTERS PATENT to Charles Louis Baud and César Henri Lecoultre, of the
Firm of Baud and Lecoultre, of Sentier, in the Republic of Switzerland, for
the Invention of "AN IMPROVEMENT IN THE CONSTRUCTION OF WATCHES."
Sealed the 8th June 1880, and dated the 9th December 1879.
PROVISIONAL SPECIFICATION left by the said Charles Louis Baud and César
Henri Lecoultre at the Office of the Commissioners of Patents on the 9th
December 1879.
CHARLES LOUIS BAUD and CÉSAR HENRI LECOULTRE, of the Firm of Baud and
Lecoultre, of Sentier, in the Republic of Switzerland. "AN IMPROVEMENT IN THE
CONSTRUCTION OF WATCHES.'
"
The object of this Invention is to provide a means for measuring the time in
minutes and seconds occupied by any given action.
To this end we fit to a watch containing the ordinary movements for marking
the seconds, minutes, and hours, two additional hands, viz., a second minute hand,
and a centre seconds hand; and these we drive by mechanism so arranged that it
can be thrown in or out of use at pleasure, these chronograph hands when the
mechanism is quiescent being capable of being returned to zero.
The chronograph bands are fitted on the central arbor between the ordinary
hour and minute hands, the seconds hand standing next the hour hand. The sleeves
of these two chronograph hands each carry a friction wheel, which are driven by
friction wheels brought into contact therewith by means of pressure springs, and
withdrawn from contact by a tappet wheel carried by a ratchet wheel actuated by
a spring pawl from a stud projecting from the rim of the watch case. The driving
friction wheels are attached to pinions which gear respectively into the minute
wheel and into the seconds wheel of the watch, and they are carried by rock
levers pinned together to ensure their simultaneous motion. The tail of one of
these levers projects into the path of the tappets of the tappet wheel, and as a
tappet strikes the tail it will rock the levers, and without disengaging their
pinions will lift the driving friction wheels clear of the central friction wheels
before mentioned, and thereby arrest the motion of the chronograph hands.
It is necessary at the moment the action of the driving mechanism is suspended
t.. lock the central friction wheels, and retain their hands in the position at which
Un G71

page_text: they have arrived. This is effected by a locking or break lever, which is held out
of action by the tappet wheel, but when released from a tappet will be forced
against the periphery of one or both of the friction wheels by a pressure spring,
and thus hold the chronograph hands at the points they have reached on the dial.
This result is obtained by moving round the ratchet wheel one tooth. When the time
indicated by the chronograph hands has been noted the ratchet wheel may be
moved forward another tooth to lift the break lever out of action, and return the
chronograph hands to zero. This back movement of the chronograph hands is
effected by a second pressure lever which boars upon the peripheries of a pair of
heart shaped cams attached to the central friction wheels. This lever is held out
of action by the tappet wheel, and when released will be forced by a spring against
the heart shaped cams, and acting upon them as a friction driver will force them
round together with the wheels to which they are attached until the hands of the
respective wheels reach zero.
The next advance of the ratchet wheel will throw the driving mechanism again
into action, when the movements above explained may be repeated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Louis Baud and César Henri Lecoultre in the Great Seal
Patent Office on the 9th June 1880.
CHARLES LOUIS BAUD and CÉSAR HENRI LECOULTRE, of the Firm of Baud and
Lecoultre, of Sentier, in the Republic of Switzerland. " AN IMPROVEMENT IN THE
CONSTRUCTION OF WATCHES."
The object of this Invention is to provide a means for measuring the time in
minutes and seconds occupied by any given action.
To this end we fit to a watch containing the ordinary movements for marking
the seconds, minutes, and hours, two additional hands, viz., a second minute hand
and a centre seconds hand, and these we drive by mechanism so arranged that it
can be thrown in or out of use at pleasure, these chronograph hands when the
mechanism is quiescent being capable of being returned to zero.
In the accompanying Drawing Fig. 1 shews in plan view (the face of the watch
being removed) so much of a watch movement with the improvement applied
thereto as will serve to explain the nature of our Invention; Fig. 2 is an enlarged
plan view of our improvements, certain of the parts being omitted to bring into
view some underlying parts and to simplify the Drawing, and Fig. 3 is a cross
section on the same scale as Fig. 2, and taken in the line 1-2 of that Figuro.
a, Fig. 1, is the chronograph minute hand, and b is the chronograph seconds
hand. The mechanism for working these hands lies between the face and the base
plate of the watch.
The chronograph hands are fitted on the central arbor between the ordinary
hour and minute hands, the seconds band standing next the hour hand. The
sleeves of these two chronograph hands each carry a friction wheel marked a¹, b',
respectively, as shewn best in the sectional view Fig. 3. These friction wheels are
driven by means of friction pinions a², b³, brought into contact therewith by a
pressure spring, as will be presently explained, and they are mounted on a rock
lever, shewn detached and in edge view at Fig. 4. This lever is composed of two
bars c, c², having a common fulcrum at c³, and forming together a compound lever.
These bars c, c', are connected together loosely by a fixed pin projecting from the
lower bar through an enlarged hole made in the upper bar. This arrangement is
adopted to give the bars a slight independent motion the one of the other, while
practically they constitute one rock lever. Upon this lever the friction pinions
a², b, are mounted, and by its means the friction pinions are held in gear with
their respective friction wheels under the pressure of the spring d, which is made
fast to a bridge and bears against the bar c. Attached to each friction pinion is
a spur pinion a³, 63, which gear respectively the one into the minute wheel of the
watch a', and the other into the seconds wheel of the watch 6, and receive there-
from a continuous rotary motion, which motion is communicated to the chrono-
graph hands, and maintained so long as the friction pinions are in gear with their
respective wheels a¹, b¹. It should be remarked that the peripheries of these
friction wheels and pinions are milled to ensure their maintaining a firm hold when
brought into contact.
For the purpose of keeping the chronograph hands out of action until required
to be used, the following contrivance is adopted :-
Underlying the free end of the compound lever is a ratchet wheel e which is
mounted on a stud pin standing up from the base plate; on the face of this ratchet
wheel is a ring of tappets e', one tappet for every three teeth of the ratchet wheel.
The tail end of the compound lever is so shaped as to engage with the tappets as
they are brought round; any rotary motion therefore imparted to the ratchet
wheel will cause the tipping of the compound lever, and thereby disengage the
friction pinions from their friction wheels.

page_text: This ratchet wheel e is actuated by a spring pawl f carried at one end of a rock
lever, which is pivotted to the base plate, and has pivotted to its opposite end a
stud projecting from the rim of the watch case. By depressing this stud the
pawlf will be caused to drive round the wheel e the distance of a tooth, the effect
of which will be to bring a tappet e¹ into contact with the compound rock lever
and rock the same.
This rocking motion will without disengaging the spur pinions
from their respective spur wheels lift the driving friction wheels clear of the friction
wheels a¹, b', and thereby arrest the motion of the chronograph hands. It is
necessary, at the moment the action of the driving mechanism is suspended, to lock
the central friction wheels, and retain their hands in the position at which they
have arrived. This is effected by a locking or break lever g, which is pivotted to
the base plate of the watch, and carries a projection which lies within the path of
the tappets e. By means of these tappets the lever is held out of action, but when
released from a tappet will be forced against the pheriphery of the wheel a' by a
pressure spring g¹, and thus hold the chronograph hands at the points they have
reached on the dial. This result is obtained when the ratchet wheel e is moved
forward one tooth to throw the friction wheels out of gear. When the time
indicated by the chronograph hands has been noted the chronograph lands may be
returned to zero. This back movement of the chronograph hands is effected by a
second pressure lever pivotted on the pivot which carries the lever g, and which
is also fitted with a projection that lies within the path of the tappets e'. The
end of this lever bears upon the periphery of a pair of heart-shaped cams a³, b,
attached respectively to the central friction wheels a, b, and lying in contact with
each other. The lever is held out of action by the tappet wheel, and when
released will be forced by a spring ², against the heart shaped cams, and acting
upon them as a friction driver will force them round together with the wheels to
which they are respectively attached until the chronograph hands reach zero.
Before however this can take place the friction wheel a' must be released from the
break lever; this is done simultaneously with the advance of the lever lt, a tappet e¹
bearing back the break lever at the moment that another tappet is disengaging
the lever h, and permitting it to come into action. The release of the lever h,
following as it does the action of the tappets on the rock lever c, is effected by a
second depression of the stud f³ and the racking round of the ratchet wheel e a
second tooth.
In restarting the chronograph hands it is only necessary to depress the stud ƒ³,
and thereby drive round the ratchet wheel the distance of a third tooth, when the
compound lever will be released from its engaging tappet, and the friction pinions
will be thrown into gear with the wheels a¹ and b² respectively.
Having now set forth the nature of our Invention of an improvement in the
construction of watches, and having explained the manner of carrying the same
into effect, we wish it to be understood that under the above in part recited
· Letters Patent, we claim, the arrangement of mechanism above described for
starting and stopping a second or additional minute hand and a centre seconds
hand and returning the same to zero, as and for the purpose above set forth.
In witness whereof, we, the said César Henri Lecoultre and Charles Louis
Baud, have hereunto set our hands and seals, this Fifth day of June, in the
year of our Lord One thousand eight hundred and eighty.