IMPROVEMENTS IN CENTRE SECOND STOP WATCHES
Year: 1879

page_text: LETTERS PATENT to Walter Hirst, William Hirst, and Joseph Hirst, all of
Sheffield, in the County of York, for the Invention of "IMPROVEMENTS IN
CENTRE SECOND STOP WATCHES."
Sealed the 9th March 1880, and dated the 30th October 1879.
PROVISIONAL SPECIFICATION left by the said Walter Hirst, William Hirst,
and Joseph Hirst at the Office of the Commissioners of Patents on the 30th
October 1879.
WALTER HIRST, WILLIAM HIRST, and JOSEPH HIRST, all of Sheffield, in the
County of York. "IMPROVEMENTS IN CENTRE SECOND STOP WATCHES."
This Invention relates to improvements in centre seconds stop watches, and
embraces two objects, first, that much smaller fractions of time may be accurately
noted than can be done with centre seconds of the ordinary construction; second,
that the pressure of the finger on the button of the stop both starts and stops the
watch alternately, and we attain these desirable objects in the following manner :-
To enable any one to read with ease much smaller fractions of time than is usual
we cause the centre seconds finger to revolve four times round the dial in one
minute instead of once, so that the divisions on the dial may be four times the size
they usually are; to accomplish this in the best manner we prefer to remove the
"fourth" wheel, which revolves once per minute from its central position, and gear
into it a wheel having only one fourth the number of teeth, and consequently
making four revolutions per minute; this wheel is fixed in the centre of the watch
and carries the centre seconds finger. But the same result may be accomplished by
more complicated and therefore inferior arrangements of wheels. The stop action
may be described as follows, and it may be placed either in the pendent or at the
side of the case, as preferred, but for example we will describe it as attached to the
pendent: A pin or propeller passing through the pendent is made to press against
the long and short end of a lever alternately. The long end of the lever when
pressed down comes in contact with the rim of the balance wheel and instantly
stops the watch; pressure on the short end of the lever releases the balance wheel
and the watch at once starts; a suitable spring catch holds the lever in either one
Dries 631

page_text: or the other position. The alternate pressure on the different ends of the lever is
thus arranged. The end of the propeller has a knife edge placed opposite a similar
knife edge on the lever, and exactly over the fulcrum of the lever. On pressing
down the propeller it passes down the right hand side of the knife edge on the
lever and forces the long end of the lever against the rim of the balance wheel,
stopping the watch, and the propeller is returned to its normal position by the
action of a spring or springs. On again pressing down the propeller it passes down
the left hand side of the knife edge on the lever, by reason of its altered position,
and acts against the short end of the lever, thus releasing the balance wheel and
starting the watch, and so on alternately.
In combination with a centre seconds finger revolving four times in one minute,
we claim the use of a dial divided into one hundred and fifty equal parts or
divisions (in addition to the ordinary figures), so that there are six hundred equal
and readable divisions in one minute, being of great use for racing purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Walter Hirst, William Hirst, and Joseph Hirst in the Great
Seal Patent Office on the 28th April 1880.
WALTER HIRST, WILLIAM HIRST, and JOSEPH HIRST, all of Sheffield, in the
County of York. "IMPROVEMENTS IN CENTRE SECONDS STOP WATCHES."
This Invention relates to improvements in centre seconds stop watches, and
embraces two objects, first, that much smaller fractions of time may be accurately
noted than can be done with centre second watches of the ordinary construction;
second, that pressure on the stop button both starts and stops the watch alternately,
and these objects are obtained in the following manner:- -To enable small fractions
of time to be read with ease we cause the centre seconds finger to make four
revolutions in one minute, so that the divisions marked on the dial are four times
the usual size, and to accomplish this we prefer to remove the "fourth" wheel,
which revolves once per minute, from its central position in the watch and gear
into it a wheel having one fourth the number of teeth, and consequently revolving
four times per minute, and which carries the seconds finger. We prefer to use the
arrangement just described, but the same result may be accomplished by a more
complicated and therefore inferior arrangement of the train of wheels.
The stop action may be described as follows, and it may be placed either in the
pendant or at the side of the case, but we will describe it as attached to the
pendant: A pin or propellor passing through the pendant is held up by a spring
or springs, but may be made to press against the opposite sides of a rocking lever
or tumbler (by preference of a heart shape), which carries or is connected with a
finger or stop that may be alternately pressed against and withdrawn from the rim
of the balance wheel; a suitable spring retains the tumbler in each position. The
end of the propellor next the heart shaped tumbler is brought to a knife edge and
can move to a limited extent sideways. On the top of the heart shaped tumbler
two grooves or notches are formed with a small projection between them having a
sharp apex, and similar in shape to a hand-saw tooth.
The tumbler vibrates on a fulcrum placed by preference near to its lower end,
which is pointed, and engages with suitable grooves or notches in a spring which
retains it in the desired positions. The normal position of these several parts is as
follows: The propellor is held up by its spring or springs out of contact with the
tumbler, the tumbler is inclined to either one side or the other and held in that
position by the spring engaged with its lower point, the finger or stop being either
in or out of contact with the balance wheel, as the case may be; to alter this
position of the stop the propellor is pressed down and slides down the side of the
projection presented to it into the groove or notch, pressing against which the
tumbler is forced over to the opposite position, and on removing the pressure the
propellor is returned to its normal position by the action of the spring or springs,
and on being again pressed down slides down the opposite side of the projection,
which is now presented to it, and so on alternately.
In combination with the centre seconds finger making four revolutions in one
minute we use a dial or face which is divided into one hundred and fifty equal
parts in addition to the ordinary divisions of time, so that there are six hundred
equal and readable divisions of one minute, a matter of great value for racing
calculations. And in order that our Invention may be fully understood we shall
now proceed more particularly to describe the same, and for that purpose shall refer
to the several figures on the annexed Sheet of Drawings, and to the letters marked
thereon. Fig. 1 represents the dial of a watch with only a portion marked or
divided, being sufficient to show the nature of our Invention, that is, inasmuch as
it is divided into one hundred and fifty equal parts.

page_text: Fig. 2 represents the stop action as described, but it is evident that modifications
may be used without departing from the spirit of our Invention. A is the head of
the propellor attached to the button B in the pendant C; D is a guard plate with
sufficient room to allow the propellor to move sideways; E is the spring to return
the propellor to its normal position; F is the heart shaped tumbler working on
the fulcrum G; H is the position of the finger or stop; 1 shows the position of the
balance wheel; Jis the spring which retains the tumbler in the different positions.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, we would observe in conclusion that what we consider to be novel and original,
and therefore claim as the Invention secured to us by the hereinbefore in part
recited Letters Patent is, first, the use of a centre seconds finger that shall make
.four revolutions of the dial in one minate; second, the use of a dial divided into
one hundred and fifty equal parts or divisions in addition to the ordinary
divisions of time for the purpose of calculating the speed of racing men; third, the
arrangement of a stopping and starting action, so that by means of pressure on the
stop the watch is stopped and started alternately, substantially as described and
illustrated; fourth, the separate or combined use of any or all of the above described
improvements in a watch or other timekeeper.
In witness whereof we, the said Walter Hirst, William Hirst, and Joseph
Hirst, have hereunto set our hands and seals, this Fourteenth day of April,
in the year of our Lord One thousand eight hundred and eighty.
WALIEK HIRST.
(L.S.)
WILLIAM HIRST. (L.S.)
JOSEPH HIRST.
(L.S.)