Improvements in Chronometers.
Year: 1889

page_text: Date of Application, 19th Aug., 1889
Complete Specification Left, 19th May, 1890-Accepted, 21st June, 1890
PROVISIONAL SPECIFICATION.
Improvements in Chronometers.
1, FERDINAND DANIEL DENCKER, of Grosse Backerstr. 22, Hamburg, in the
Empire of Germany, Watchmaker, do hereby declare the nature of this invention
to be as follows :-
My invention relates to chronometers and it has for one of its objects to prevent the
air within the box of the chronometer from mixing with the outer atmosphere, either
when the instrument is on shore or on sea, and thereby to preserve the mechanism,
especially the steel balance, from corrosion. This object is effected by making only
necessary openings in the box and by keeping these openings hermetically closed.
Instead of as formally attaching the suspension device to the box or case by means
of screws fitting into holes bored through the shell of the case I fasten it to a closed
ring which is slipped over the case and firmly secured thereto by means of set-screws
which enter into small recesses on the outer face but do not pass through the shell of
the case.
This arrangement may be adopted for controlling or regulating the suspension
device.
The glass above the dial is pressed tightly against an elastic greased ring (fitted in
a shallow groove in the flange of the chronometer case) by means of a metal ring
provided with an annular groove for the reception of the edge of the glass plate. Set
screws are provided in the metal ring which clamp the glass plate between the said
metal ring and the said packing-ring and thus the case is secured in an air-tight
manner on its upper part.
The key-winder is guided in a stuffing box in the bottom of the case opposite the
spindle of the spring-barrel and is provided with a ratchet or crown-wheel engaging
into a corresponding wheel fitted loosely on the shaft of the spring-barrel. To the
stem of the key-winder is hinged a handle the under face of which is pressed against
a washer on top of the stuffing box by the tendency of a spiral spring which is coiled
around the stein of the key-winder and interposed between the said crown wheel and
stuffing box.
The stem of the key-winder passes through a number of greased packing rings
which are fitted inside the stuffing box.
When winding up the chronometer the crown wheel attached to the stem of the
key-winder and acted upon by the spiral spring will engage with the corresponding
crown or ratchet wheel which is attached to the shaft of the spring barrel in such a
manner as to be moved towards the wheel on the stem by a suitable spring. When
the stem is turned in the wrong direction, the spring which presses against the crown
wheel on the spindle of the spring-barrel will yield under the pressure of the teeth of
the ratchet wheel secured to the stem of the winder.
In order to disengage the clockwork from the key-winder, the handle of the latter
is provided with two rods either of which will bear under the tendency of a spring
against the hereinbefore mentioned washer of the stuffing box when the handle is
turned down, and thereby the stem of the key-winder is axially moved within the
stuffing box and the crown-wheel which is fastened to the stem is set out of gear with
the corresponding crown wheel of the spring-barrel.
Dated this 19th day of August 1889
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Chronometers.
I FERDINAND DANIEL DENCKER, of 22 Grosse Bäckerstrasse, Hamburg, in the
Empire of Germany, Watchmaker, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
My invention relates to chronometers and it has for one of its objects to
prevent the air within the box of the chronometer from mixing with the outer
atmosphere, either when the instrument is on shore or on sea, and thereby preserving
the mechanism especially the steel balance, from corrosion.
This object is effected by making only such openings in the box as are absolutely
necessary and by keeping these openings hermetically closed.
I attain this object by the mechanism illustrated in the accompanying drawings,
in which
Figure 1 is a vertical section of my improved chronometer-casing.
Figure 2 is a view from below of the case with the key winder and
Figures 3 to 5 represent the construction of the key winder to an enlarged scale.
Instead of as formerly attaching the suspension device to the box or case by means
of screws fitting into holes bored through the shell of the case I fasten it to a closed
ring a which is slipped over the case and firmly secured thereto by means of set
screws a¹ which enter into small recesses on the outer face but do not pass through
the shell of the case.
This arrangement may be adapted for controlling or regulating the suspension
device.
The glass b above the dial is pressed tightly against an elastic greased ring b' (fitted
in a shallow groove in the flange of the chronometer case) by means of a metal ring b
provided with an annular groove for the reception of the edge of the glass plate.
Set screws are provided in the metal ring which clamp the glass plate between
the metal ring 3 and the packing ring 6' and thus the case is secured in an air-tight
manner on its upper part.
The key-winder is guided in a stuffing box d in the bottom of the case opposite the
spindle of the spring-barrel and is provided with a ratchet or
crown wheel c¹
engaging with a corresponding wheel fitted loosely on the shaft of the spring-barrel.
To the stem c of the key-winder is hinged a handle c³ the under face of which is
pressed against a washer on top of the stuffing box d by the tendency of a spiral
spring which is coiled around the stem of the key-winder and interposed between
the said crown wheel c¹ and stuffing box d.
The stem c of the key-winder passes through a number of greased packing rings d²
which are fitted inside the stuffing box d.
When winding up the chronometer the crown wheel c' attached to the stem of the
key-winder and acted upon by the spiral spring c² will engage with the corresponding
crown or ratchet wheel c which is attached to the shaft of the spring barrel in such a
manner as to be moved towards the wheel on the stem by a suitable spring c. When
the stem c is turned in the wrong direction the spring c which presses against the
crown wheel c on the spindle of the spring-barrel will yield under the pressure of the
teeth of the ratchet wheel c¹ secured to the stem of the winder.
In order to disengage the clockwork from the key-winder, the handle c³ of the
latter is provided with two noses c either of which will bear under the tendency of a
spring against the hereinbefore mentioned washer of the stuffing-box d when the
handle c³ is turned down, and thereby the stem of the key-winder is axially moved
within the stuffing box d and the crown-wheel c¹ which is fastened to the stem is set
out of gear with the corresponding crown wheel e of the spring barrel.
The stuffing-box d is fastened to the bottom of the chronometer-case by means of

page_text: a convenient number of screws the bore-holes of which do not extend through the
bottom of the case, in order to prevent the air to pass into the interior of the case.
By the aid of a greased packing-ring d¹ the flange of the stuffing box d is fitted air
tight to the bottom of the case.
I am aware that prior to my invention chronometer cases with stuffing hoxes
and packing rings have been employed for rendering chronometer cases air-tight
I do not therefore claim such combination broadly.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I declare that what I
claim is :-
First. As an improvement in chronometers, the combination of the key winder,
consisting of the stem e provided with a crown-wheel c¹ adapted to engage with a
corresponding wheel of the chronometer work, the stuffing box d, spring c² and
handle e provided at its base with noses c, which are adapted to bear against the
stuffing box d under the action of the spring c² when the hinged handle is turned
aside, substantially as and for the purpose set forth.
Second. In combination with an air-tight chronometer case a separate ring a
attached to the case by means of set screws a¹ and adapted to form the frame for
fastening the actual parts of the universal suspension, substantially as set forth.
Dated this 19th day of May 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.