AN IMPROVED CONSTRUCTION OF CHRONOMETER CASE
Year: 1858

page_text: LETTERS PATENT to Edward Daniel Johnson, of Wilmington Square,
in the County of Middlesex, Watch and Chronometer Maker, for the
Invention of
AN IMPROVED CONSTRUCTION OF
CHRONOMETER CASE
Sealed the 13th July 1858, and dated the 13th February 1858.
PROVISIONAL SPECIFICATION left by the said Edward Daniel Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 13th February 1858.
I, EDWARD DANIEL JOHNSON, of Wilmington Square, in the County of
Middlesex, Watch and Chronometer Maker, do hereby declare the nature of
the said Invention for "AN IMPROVED CONSTRUCTION OF CHRONOMETER CASE," to
be as follows:-
The object of this Invention is to prevent the air within the box of the
chronometer from mixing with the outer atmosphere, both when on shore and
at sea, and thereby to preserve the mechanism and more particularly the
delicate steel work from corrosion. This result I propose to attain by the
following alterations in and additions to the ordinary brass box of the chrono-
meter:―
The glass bizzle is made to slide instead of screw on, and is furnished with
a lip which laps over the box, beyond the bottom of the slip or junction. The

page_text: ordinary glass is cemented instead of merely snapped into its seat, and a ring
of valcanized india-rubber or other suitable material is interposed between the
cover and box. The cover is then pressed down and kept in this position by
three or more small screws through the before-mentioned lip, and the case is
thereby rendered air-tight at the upper part.
The winding key is made of the ratchet form, and has a long cylindrical
nose passing through a stuffing box in the bottom of the case opposite
the winding square, and is kept out of contact with the square by a coiled
spring slipped on the nose.
For the purpose of effectually preventing the access of air to the case
through the keyhole, the stuffing box, spring, and key (except the handle) are
enclosed in a bag or tube of vulcanized rubber, or other suitable air and water-
proof material, one edge of which is secured to the bottom of the case by a
ring and screws, and the other end to the top of the ratchet box of the key
in a similar manner.
To set the winding key in action, it is pressed forward on to the square of
the fuzee, and when in that position an alternating axial motion is given to the
key handle, the movement in one direction turning the fuzee square, and the
other replacing the handle of the key in the proper position for repeating
the action, the elasticity of the bag allowing for this motion of the key.
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 13th August 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
DANIEL JOHNSON, of Wilmington Square, in the County of Middlesex, Watch
and Chronometer Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of February, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Edward Daniel Johnson, Her special license 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

page_text: of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "AN IMPROVED CONSTRUCTION OF CHRONOMETER CASE," upon the
condition (amongst others) that I, the said Edward Daniel Johnson, by an
instrument in writing under my hand and seal, 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 is
to be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
The object of this Invention of "An Improved Construction of Chronometer
Case," is to prevent the air within the box of the chronometer from mixing
with the outer atmosphere, or the external air from entering the chronometer
case either when the instrument is on shore or at sea. By thus excluding the
external atmosphere, the mechanism of the instrument, and more particularly
the delicate steel work, will be preserved from corrosion. This result I
propose to attain by the following alterations in and additions to the
ordinary brass box or case of the chronometer:-
The glass bizzel is made to fit or slide on instead of being screwed on as
heretofore, and it is furnished with a lip which laps over the box beyond the
bottom of the slip or junction, and rests against a shoulder. The ordinary
glass is cemented in its place instead of being merely snapped or sprung into
its seat as usual, and a ring of vulcanized india-rubber or other suitable
material is interposed between the cover and the box or case.
The cover is
then pressed down and kept in this position by three or more small screws or
pins being passed or screwed through the before-mentioned lip, and caused to
enter holes made in the metal of the case which is thereby rendered air-tight
at the upper part.
The winding key is made of the ratchet form, and an additional long
cylindrical nose or pipe is adapted to the case and made to pass through a
stuffing box in the bottom of the case opposite the winding square, and is kept
out of contact with the square by a coiled or other suitable spring that is
slipped on and surrounds the nose or pipe.
For the purpose of effectually preventing the access of air to the case
through the keyhole or winding hole, the stuffing box, spring, and nose of the
key are enclosed-in a bag. or case formed by a disc or sheet of vulcanized

page_text: rubber or other suitable air and water-proof material, the edges of which are.
secured to the bottom of the case by a ring and screws. The nose of the key
or winding instrument passes through an opening in this india-rubber disc or
sheet, the edges of which opening are secured between clamping rings.
In order to bring the nose of the key or winding instrument into a position
to act, it is pressed forward on to the square of the fuzee by means of the key:
handle, and when in that position an axial motion is given to the key handle,.
and the fuzee square is turned.
In the accompanying Drawing, Fig. 1 is a plan view of the back of a
chronometer case with my improvements adapted thereto, and shewing the
keyhole and the thin disc or sheet of india rubber, whereby the moveable nose:
is secured to the case by an air-tight joint. Fig. 2 is a transverse vertical
section of the case shewing the key or handle detached. The ordinary chrono-.
meter case is shewn at a, a; b is the face plate or dial; c, c, the ring or bizzel
for receiving the glass d, which is cemented into its seat. Instead of the ring
c being screwed on to the case as heretofore, it is fitted on to and slipped over
the top and rests on a shoulder c, e, on which is placed a ring of india-rubber
or some other suitable material f, which when compressed forms an air and
water-tight joint.. The ring c is secured to the case a by means of screws g, g,
(Figures 1 and 2), which pass through it. It will be seen that the under side
of the shoulder e, e, is bevelled, and that as the screws g,g, bear against it they
will compress the india-rubber ring by drawing the ring c down towards the
shoulder e.
The keyhole of the case is provided with a stuffing box h, through which
passes the moveable nose piece i, having a square hole made therein to fit the
end of the winding spindle or fuzee square. The upper end of the nose i is
made square and fits a corresponding hole in the pipe of the key or handle j,
as is well understood. The nose piece i is also provided with a disc kc, with a
double bevilled edge, which is enclosed between two rings of brass l, l, which
are held together and made to clasp the disc k closely by means of a piece of
vulcanized india-rubber which is strained round them, and is secured thereon,
by means of a string or cord, as shewn in the detached views of this part at
Figs. 3 and 4. Under the disc k is a coiled spring m, which keeps the nose i
and its appendages away from the square end of the winding spindle of the
chronometer when the winding operation is completed; the whole is covered
up by a sheet of vulcanized india-rubber, which is secured at its edges to the case
by means of a ring n, and thereby forms a kind of bag or case to enclose
these parts. The ring n is fastened down by screws o, o, which pass through
it and enter holes tapped in the case, as shewn in Fig. 2. The square end of

page_text: the nose passes through an opening in the india-rubber disc, the edges of which
are secured by the clamping rings 1 and p, Figures 1 and 2.
Having now described my Invention of "An Improved Construction of
Chronometer Case," and having explained the manner of carrying the same
into effect, I claim the mode herein described of rendering chronometer cases
air-tight; I also claim the mode shewn and described of adapting the moveable
nose piece or key for winding up the instrument so that the works may be
relieved of the weight of the key or winding instrument, except when the
winding operation is being performed.
In witness whereof, I, the said Edward Daniel Johnson have hereunto
set my hand and seal, the Thirteenth day of August, in the year of
our Lord One thousand eight hundred and fifty-eight.
Witness,
C. J. WINTERSGILL,
66, Chancery Lane.
E. D. JOHNSON. (L.S.)