A NEW AND USEFUL IMPROVEMENT IN CHRONOGRAPHS OR STOP WATCHES
Year: 1881

page_text: LETTERS PATENT to Lorentz Albert Groth, K.G.V., Civil Engineer and
Proprietor of the Scandinavian Patent Office, under the Firm of L. A. Groth
& Co., 97, Finsbury Pavement, London, and 20, Forhaabningsholms Allee,
Copenhagen, for an Invention of "A NEW AND USEFUL IMPROVEMENT IN
CHRONOGRAPHS OR STOP WATCHES." A communication from abroad by
Henry Alfred Lugrin and Prosper Nordmann, both of New York City, in
the County and State of New York, United States America.
PROVISIONAL SPECIFICATION left by the said Lorentz Albert Groth at
the Office of the Commissioners of Patents on the 19th May 1881.
LORENTZ ALBERT GROTH, K.G.V., Civil Engineer and Proprietor of the Scandinavian
Patent Office, under the Firm of L. A. Groth & Co., 97, Finsbury Pavement,
London, and 20, Forhaabningsholms Allee, Copenhagen. "A NEW AND USEFUL
IMPROVEMENT IN CHRONOGRAPHS OR STOP WATCHES." A communication from
abroad by Henry Alfred Lugrin and Prosper Nordmann, both of New York City,
in the County and State of New York, United States America.
This Invention has reference to improvements in stop-watches used for timing
races, by physicians, and for other purposes, and the Invention consists in passing
the arbor of the quarter second hand through the hollow arbor of the centre-wheel
of the watch train, and supporting the former by a shoulder near its front end on
an end collar of the hollow arbor, so that the arbor of the quarter second hand may
oscillate on this support.
To the opposite end of the arbor of the quarter second hand is keyed a gear-
wheel, which is thrown into gear with an intermediate pinion operated by a
transmitting wheel of the fourth wheel of the watch by a friction spring after
withdrawing the returning spring and shifting lever of the arbor of the quarter
second hand. The oscillating end of the arbor is guided in suitable manner, and
its gear wheel thrown out of gear with the intermediate pinion by a return lever
which bears on the circumference of the gear wheel. The quarter second hand is
then returned to the point of starting by the usual shifting mechanism, and held
in this position by the retaining spring and an intermediate oscillating arm, the
return lever being at this point removed from the gear wheel of the arbor.
To start the timing hand the shifting lever and retaining spring are carried away
from the heart cam and arbor by a suitable ratchet, pawl, and lever-mechanism,
which also actuates the return lever of the arbor.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Lorentz Albert Groth in the Great Seal Patent Office on the
16th November 1881.
LORENTZ ALBERT GROTH, K.G.V., Civil Engineer and Proprietor of the Scandinavian
Patent Office, under the Firm of L. A. Groth & Co., 97, Finsbury Pavement,
London, and 20, Forhanbningsholms Allee, Copenhagen. "A NEW AND USEFUL
IMPROVEMENT IN CHRONOGRAPHS OR STOP WATCHES." A communication from
abroad by Henry Alfred Lugrin and Prosper Nordmann, both of New York City,
in the County and State of New York, United States America.
This Invention has reference to improvements in stop-watches used for timing
races, by physicians, and for other purposes, and the Invention consists in passing
the arbor of the quarter second hand through the hollow arbor of the centro wheel
of the watch-train, and supporting the former by a shoulder near its front end on
an end collar of the hollow arbor, so that the arbor of the quarter second hand may
oscillate on this support. To the opposite end of the arbor of the quarter second
hand is keyed a gear wheel, which is thrown into gear with an intermediate pinion
operated by a transmitting wheel of the fourth wheel of the watch by a friction
spring after withdrawing the returning spring and shifting lever of the arbor of
the quarter second hand. The oscillating end of the arbor is guided in suitable
manner, and its gear wheel thrown out of gear with the intermediate pinion by a
return lever which bears on the circumference of the gear wheel. The quarter
second hand is then returned to the point of starting by the usual shifting
mechanism, and held in this position by the retaining spring and an intermediato
oscillating arm, the return lever being at this point removed from the gear wheel of
the arbor. To start the timing hand the shifting lever and retaining spring is
carried away from the heart cam and arbor by a suitable ratchet, pawl, and lever
mechanism, which also actuates the return lever of the arbor.
In the accompanying Drawings Fig. 1 represents a top view of the improved
stop watch drawn on an enlarged scale, with part of the top bridge broken away to
show the working parts below; Fig. 2 is a vertical central section of the same on
line x, x, Fig. 1, and Figs. 3 and 4 are detail views of the mechanism for shifting
the arbor of the quarter second hand and throwing the gear wheel of the same
respectively out of or into gear with the transmitting pinion. Similar letters of
reference indicate corresponding parts.
In the Drawings A represents the arbor of the quarter second hand A', which
arbor is passed through the hollow arbor B of the centre wheel B'of the watch
movement. The arbor A of the quarter second hand A¹ passes by a short end stud
or pin a through a central perforation in the face collar of the hollow arbor B, and
rests by means of a shoulder b upon the face collar of the hollow arbor B¹ so as to
be capable of a slight oscillating motion upon this support. To the opposite or top
end of the arbor A is keyed the actuating gear wheel C of the quarter second
hand A', which gear which is provided with minute teeth, and adapted to be thrown
into gear with an intermediate pinion C' which receives motion from a gear
wheel C fixed upon the arbor of the fourth wheel of the watch train. The top-
end of the arbor A is guided in a slot in the top bridge D, said slot being in line
with the arbor of the fourth wheel, and of sufficient length to admit the arbor A to
oscillate sufficiently for throwing the actuating gear wheel C into gear with the
transmitting pinion C¹.
In place of the guide slot d of the top bridge a guide arm or any other equivalent
device may be used. A friction spring e presses upon one side of the arbor A, and
shifts the arbor A and its gear wheel Ċ towards the pinion C¹ as soon as the

page_text: As
opposing pressure upon the other side of the arbor is removed. The spring e also
serves to retain the gear wheel C in gear with the transmitting pinion C after it
is thrown into gear therewith. For the purpose of throwing the actuating gear
wheel C out of gear with the pinion C' a return lever E is employed, which is
pressed by its spring shank against the circumference of the gear wheel C, so as to
carry the same with its arbor sideways in the slot of the bridge, and withdraw the
gear wheel C from the pinion C¹. During this motion the lower part of the arbor A
changes but interceptibly its position on the seat of the hollow arbor of the
centre wheel, as the oscillating motion required for withdrawing the gear wheel C
from the pinion C is not considerable owing to the smallness of the teeth.
soon as the gear wheel C is thrown out of gear with the pinion, the shifting lever F
which is used in all stop watches is carried back upon a heart-cam of the arbor A,
and thereby the quarter-second hand returned to the starting point. The shifting
lever F is in this case on the same side as the return lever E, which is released
from the gear wheel at the same moment when the shifting lever engages the
heart cam, so that the return lever cannot in any way injure the minute teeth of
the gear wheel C or impede the motion of the same. The arbor A is held in
ungeared position by means of a retaining spring f which bears on a pivot arm f¹,
which extends transversely across the slot d of the bridge of the arbor A opposite
to the contact side of the spring e. Whenever it is desired to start the quarter
second hand and throw the actuating gear wheel C into gear with the pinion C₁,
the shifting lever F as well as the retaining spring f have to be released from the
heart cam and pivot arin f' respectively, the shifting lever being first thrown back
sufficiently, so that a fixed pin g of the same engages the spring f* and carries it
along with the lever and away from the pivot arm f¹. As the prssure on the
arbor is thereby released the friction spring e is thereby enabled to throw tho
arbor A and gear wheel C towards and into gear with the transmitting pinion C¹.
The different levers and springs by which the quarter second hand is started,
stopped, or returned to the starting point, are actuated by any suitable lever, ratchet,
and pawl device, that shewn in the Drawings consisting of a fulcrummed lever G,
which is operated by a push pin G; a pivoted spring pawl G2 at the opposite
end of the fulcrummed lever G engages a ratchet wheel H, to which a face
plate H with larger spurs and intermediate recesses is secured.
A check pawl
retains the ratchet wheel when the spring pawl is sprung from one tooth of the
ratchet into another. By depressing the push pin G' the pawl G³ moves the
ratchet H, which engages by one of the enlarged spurs of its face plate H' a
projecting heel of the shifting lever F, so as to force the lever, and with it the
retaining spring f, back clear of the arbor A. The friction spring e is thereby
enabled to throw the arbor A sideways, securing the intermeshing of gear-wheel C
and pinion C¹, and the starting of the quarter second hand. During this motion
of the ratchet wheel the heel h of the return lever E has remained in contact with
the face of one of the larger spurs of the face plate, so as to keep the same off the
gear wheel C. The next depression of the push pin G', and the corresponding
inotion of the ratchet wheel H, throws the heel of the return lever E into the
adjoining recess of the face plate H, and applies thereby the lever E to the gear
wheel C, withdrawing the same from the pinion C and stopping the quarter
second hand. During this motion of the ratchet wheel the heel of the shifting
lever has been in contact with the outer surface of the enlarged spurs of the face
plate, which holds the shifting lever clear of the heart-cam.
A third depression of the push pin G₁ brings the heel ¹ of the return lever E
again on the outer surface of the next spur of the face plate H, so as to withdraw
the lever E and remove it from the gear wheel, while simultaneously the heel of
the shifting lever F drops into the next recess, so as to apply the end of the
shifting lever F to the beart cam, and the retaining spring f to the pivot arm f', by
which the quarter second band is returned to the starting point and the arbor A of
the quarter second hand prevented from following the pressure of the friction
spring b. The arbor A is now ready for the next starting of the quarter second

page_text: hand on throwing the shifting lever and retaining spring clear of the heart cam
and arbor.
The construction described is adapted for use with any watch movement, it being
arranged on the top of the same. It can also be worked in connection with any
other wheel of the movement in place of the fourth wheel if desired.
Having now described the nature of the said Invention, and the manner
in which the same is to be performed, I would have it understood that what I
claim is,
1st. In a stop watch, the combination with the hollow arbor of the centre wheel,
having a perforated end collar or seat of the arbor of the quarter second hand
which is supported on the collar of the hollow arbor by a shoulder or enlargement,
so that the arbor of the quarter second hand is adapted to oscillate thereon,
substantially as and for the purpose set forth.
2nd. The combination of the oscillating and guided arbor of the quarter second
hand with a friction spring pressing on one side and a retaining spring and pivot
arm pressing on the other side of the arbor, substantially as described.
3rd. In a stop watch, the combination with the hollow arbor of the center wheel
of the arbor of the quarter second hand which passes through the former, and
with means substantially as described whereby the front part of the arbor of the
quarter second hand is supported, so that its opposite end may be oscillated,
substantially as specified.
4th. The combination in a stop-watch of the oscillation arbor of the quarter second
hand, having a shifting heart can with a shifting lever, having a projecting pin and
a returning spring, and with a ratchet pawl and lever mechanism, whereby the
shifting lever is first removed from the heart cam and then the returning spring
released from the arbor, substantially as specified.
5th. In a stop watch, the combination of an oscillating and spring pressed arbor of
the quarter second hand and its actuating gear wheel with a return lever, a shifting
lever, and a retaining spring, all at one side of the arbor, and with a ratchet, pawl,
and lever mechanism, whereby the retaining devices of the arbor are first released
the return lever next applied to the gear-wheel, and finally the return lever released,
from the gear wheel, and the refaining devices applied so that the quarter second
hand is either started, stopped, or returned to the starting point, substantially as
set forth.
6th. In a stop watch, the combination of the oscillating and spring pressed arbor
of the quarter second hand and its actuating gear wheel with a return lever and
a shifting lever having a retaining spring, and with a ratchet, pawl, and lever
mechanism, whereby the return lever is applied to the gear wheel, while the
shifting lever and retaining spring are released from the gear wheel, after which
they are re-applied thereto, substantially as herein described.
In witness whereof, I, the said Lorentz Albert Groth, have hereunto set
my hand and seal, this Fourteenth day of November, in the year of our
Lord One thousand eight hundred and eighty one.
LORENTZ ALBERT GROTH. (L.S.)