IMPROVEMENTS. IN THE CONSTRUCTION OF POCKET WATCHES
Year: 1868

page_text: LETTERS PATENT to Edward Daniel Johnson, of Wilmington Square,
in the County of Middlesex, Watchmaker, for the Invention of
"IMPROVEMENTS. IN THE CONSTRUCTION OF POCKET WATCHES."
Sealed the 4th August 1868, and dated the 21st March 1868.
PROVISIONAL SPECIFICATION left by the said Edward Daniel Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 21st March 1868.
I, EDWARD DANIEL JOHNSON, of Wilmington Square, in the County
of Middlesex, Watchmaker, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF POCKET WATCHES,'
to be as follows:-
"+
The object of this Invention is to measure with great accuracy
intervals of time, whether long or short, without disturbance to the
going of the watch, and also with the power of ascertaining even in.
the dark the position of the index when started, thus avoiding the
to all known.
principal cause of errors in observation common
chronographs.

page_text: The Invention is applicable to watches fitted either with a centre
seconds hand or split seconds hand, or the double seconds form, viz.,
the centre and side seconds combined.
To effect the above-named objects I use the automaton seconds
mechanism patented by me 5th August 1861 (No. 1941) as the basis of
the whole apparatus, substituting a cam plate, ratchet wheel, push piece,
and pawls for the old pressure pressure piece used to depress the annulus
arm of my former arrangement, which arm throws the seconds hand
out of action. This arrangement enables me to depress the arm by
two steps or stages the use of which will be apparent hereafter.
Secondly. I employ a complete heart-shaped motion, attaching the
springs of said motion to a disc or bar fitted to the loose seconds arbor
and the heart piece to the under side of the hour wheel cock through
which the arbor passes. The use of this heart-shaped motion is to
return the seconds hand or index when out of use to the zero point.
Thirdly. I apply a brake or rock lever, which is acted upon by a
portion of the cam plate and is made to press upon the disc of the
index in order to retain the index in the position it has at that moment
attained when stopped by the annulus. This brake lever is held against
the cam plate by a spring, and notches are made in the cam plate by
which the pressure of the brake is removed from the disc.
Fourthly. In order to indicate that the heart-shaped motion has
thrown back the index to zero I sound a bell or gong spring which
is affixed to the plate of the watch in the same plane as the cam
plate. The periphery of this plate is fitted with cam projections placed
at proper intervals to operate upon the spring simultaneously with
the return of the index to zero.
By the mechanism above described the following effects are
produced :- Supposing the object desired is to measure a short
period of time without viewing the watch, and that the index is
standing at zero, by pressing the button on the pendent the index
will be started. On repeating the pressure the index is suddenly
arrested and retained at its advanced position, where it may be
left for any length of time without interfering with the going of
the watch. A third pressure on the button instantly returns the index
to zero, and simultaneously an audible signal will indicate that return.
This return of the index to zero I have said is effected by the heart-
shaped movement, but it is only at the intermediate position of the

page_text: annulus that the index disc is sufficiently relieved from pressure to
allow the heart-shaped movement to come into action, and it is therefore
for this object that the depression of the annulus is effected by steps
or stages as before mentioned. The under face of the cam plate is
so shaped as to impart by its rotation the requisite movements to the
annulus.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Daniel Johnson in the Great Seal Patent
Office on the 21st September 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
DANIEL JOHNSON, of Wilmington Square, in the County of Middlesex,
Watchmaker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of March, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Edward Daniel Johnson, Her special licence
that I, the said Edward Daniel Johnson, my executors, administrators,
and assigns, or such others as I, the said Edward Daniel Johnson, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN THE CONSTRUCTION OF POCKET WATCHES," upon the condition (amongst
others) that I, the said Edward Daniel Johnson, my executors or
administrators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Edward Daniel Johnson, do hereby.
declare the nature of my said Invention, and in what manner the same
s to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the Drawing hereunto

page_text: annexed and to the letters and figures marked thereon (that is to
say) :-
The object of this Invention is to measure with great accuracy
intervals of time, whether long or short, without disturbance to the
going of the watch, and also with the power of ascertaining even
in the dark the position of the index when started, thus avoiding.
the principal cause of errors in observation common to all known
chronographs.
The Invention is applicable to watches fitted either with a centre
seconds hand or split seconds hand, or the double seconds form, viz.,
the centre and side seconds combined.
To effect the above-named objects I use the automaton seconds
mechanism patented by me Fifth August One thousand eight hundred
and sixty-one (No. 1941) as the basis of the whole apparatus,
substituting a cam plate with ratchet teeth, push piece, and pawls for
the old pressure piece used to depress the annulus arm of my former
arrangement. In combination with this means of depressing the
annulus arm (which determines the action or quiescence of the centre
seconds hand, I employ what is known in the trade as a heart-shaped
motion to return the seconds hand (when its use as an index has
ceased) to the zero point. And in order to indicate that the heart-
shaped motion has thrown back the index to zero, I provide for the
sounding of a signal by the use of a bell or gong spring set in action
by the mechanism.
In the accompanying Drawing Fig. 1 shews in plan view on an
enlarged scale my improvements applied to a centre seconds watch;
Fig. 2 is a plan of the heart-shaped motion detached; and Fig. 3 is an
edge view shewing its connection with the means used for driving and
stopping the centre seconds hand; Fig. 4 is a sectional elevation taken
at the line 1, 2, of Fig. 1, and shewing the parts in their normal
position as in Fig. 1; and Fig. 5 is a similar view, but representing
the parts in the position they will assume when the seconds hand is
driven.
A is the push piece operated by means of a spring stop or button B
which is connected to the push piece by a pin that passes through the
stem of the watch pendent. Pivotted to this push picce is the pawl C
which takes into ratchet teeth on the periphery of the cam plate D for
the purpose of driving that plate, and is held in contact with the teeth

page_text: by a spring C*. The cam plate is mounted on a stud axle fixed in
the plate of the watch, and its position is maintained by a spring click.
On its under side the plate D carries a ring of cams, say, nine in
number, which are formed by cutting notches equidistant from each
other through a cylindrical projection or flange on the under face of
the plate, and the lower edge of these cams is chamfered as shewn at
Figures 4 and 5. E is the annulus arm, and across it is formed a rib or
projection. The cam plate, it will be seen, overlies this projection in
such a manner that as the plate rotates its cams will be brought in
succession into contact with the projection, and thereby the annulus
arm will be depressed to the position of Fig. 5. When this takes place
the seconds hand F will be put in motion. The cams serve also to set
the "heart-shaped motion" in action, as will be now explained. G is
a heart-shaped piece made fast to the loose axle that carries the seconds
hand, and to the under side of this piece G the springs H are attached,
which connect (through friction of contact) the running friction disc I
with the loose seconds hand axle, as explained in the Specification of
my Patent above referred to. Below these springs is situate the annulus
arm E, which is elastic and has an upward "set" which gives it a
tendency to press upwards the springs H and hold them out of contact
with the disc I, as shewn at Figures 3 and 4, thereby leaving the centre
seconds hand quiescent. Upon the periphery of the heart-shaped
piece G bears the V-edged termination of a rock lever K, which is
pivotted to the plate of the watch, and has a short limb, the end of
which rides upon the side of the cams. As, however, these cams
severally pass away from under the short limb of the rock lever a notch
or space will be presented to it, and by means of a pressure spring K*
used to hold the V edge of the lever in contact with the heart-shaped
piece, the short limb will fall into the notch and thus allow the V edge
to approach and bear upon the periphery of the heart-shaped piece G.
The ratchet teeth by which the pawl C drives the cam plate, it will be
seen, have every third tooth left longer than the others; this is to allow
of their reaching (in their rotation) a spring gong L made fast to the
plate of the watch, and thereby of producing an audible signal.
By the mechanism to which I have now referred in detail the following
effects are produced:-Supposing the object desired is to measure a
short period of time without viewing the watch, and that the index F
is standing at zero, by pressing the button B on the pendent the index
will be started, that is to say, the pawl C will move round the cam plate
:

page_text: one tooth and throw the rock lever K into the dotted position of Fig. 1,
thereby leaving the heart-shaped piece free to move; at the same time
the cam plate will depress the annulus arm to the position of Fig. 5,
and the springs H will then make contact with the driving disc I. On
repeating the pressure on the button the advance of the index will be
suddenly arrested, and it will be retained at its advanced position, where
it may be left for any length of time without interfering with the
going of the watch. This result is due to the release of the annulus
arm from the downward pressure of the cam, which by reason of the
further axial motion of the cam plate is moved clear of the projection
on the arm, and allows the arm to rise and lift the springs off the driving
wheel. A third pressure on the button instantly returns the index to
zero. This motion is due, as is well understood, to the pressure of the
rock lever K on the periphery of the heart-shaped piece, which pressure
gives it an axial motion that is arrested by the V edge entering the
indent in the periphery of the heart-shaped piece. Simultaneously with
the return of the index to zero an audible signal produced by the spring
gong L will indicate that the return of the index has been effected.
Having now set forth the nature of my Invention of "Improvements
in the Construction of Pocket Watches," and explained the manner of
carrying the same into effect, I wish it to be understood that under the
above in part recited Letters Patent I claim, starting and stopping the
centre seconds hand or index and returning the same to zero, and giving
notice of its return by an audible signal, in the manner and for the
purpose above set forth.
In witness whereof, I, the said Edward Daniel Johnson, have
hereunto set my hand and seal, the Twenty-first day of September,
in the year of our Lord One thousand eight hundred and sixty-