IMPROVEMENTS IN WATCHES AND POCKET CHRONOMETERS
Year: 1872

page_text: LETTERS PATENT to Aaron Lufkin Dennison, of Handsworth, in the
County of Stafford, Watch Manufacturer, for the Invention of
.66
"IMPROVEMENTS IN WATCHES AND POCKET CHRONOMETERS."
Sealed the 19th July 1872, and dated the 3rd February 1872.

page_text: require cleaning only at long intervals, and from the construction
cases are little liable to accidental injury.
I will describe my Invention with reference to a watch. In place of the
ordinary hinged bezel for holding the glass I employ a bezel having a
screw thread on its periphery, which screw thread takes into a corresponding
concave screw thread in the front dome of the case. The glass is bur-
nished in the said bezel at a level below the top of the bezel, and when
the bezel is screwed into its place in the case the said case is closed air
and water tight. The thickness of the case required for the bezel screw
enables it to support the dome upon the bottom plate directly over the
pillars in the same, so that with a top plate thick enough to fill the dome
on the back or near side the case of the watch has a much greater
strength than ordinary cases. I introduce the movements into the case
from the back instead of from the front as usual. In securing the back
of the case in its place I dispense with a hinge, and connect it to the
case by a screw thread on its edge engaging with a corresponding screw
thread in the case. A button or thumb piece is provided for facilitating
the motion of the back in screwing and unscrewing.
In order more effectually to secure the air and water tight character
of the case I make the winding arbor which passes through the stem of
the pendant, and the push piece which passes through the edge of the
case for the purpose of setting the hands, work in packings so that they
may work air and water tight. I make a depression in the edge of the
case where the push piece is situated so as to prevent the said push piece
projecting beyond the edge of the case.
Instead of using the ordinary gearing on the winding spindle and
spring barrel I employ gearing wheels made of two parts, one part being
composed of bevilled and the other of straight teeth.
.:
In the mechanism for setting the hands I dispense with the usual
intermediate gearing between the clutch piece and the minute wheel,
and I make the minute wheel of steel with strong teeth, one-half of the
several teeth being straight for the purpose of engaging with the cannon
pinion, and the other half bevilled to be operated upon by the clutch
gear for setting the hands.
In place of the ratchet wheel used in the winding mechanism I make
use of the ordinary gear, and employ a click having two or more teeth
of a shape proper.to engage with the teeth of the said gear...

page_text: I arrange the parts of the winding mechanism under a solid block:
secured to the bottom or pillar plate, the said parts working in suitably:
formed recesses in the said block, the said parts occupying the said.
recesses with only sufficient freedom to allow of their proper play. This
arrangement allows the winding spindle to be introduced and removed
without difficulty. This block serves in place of two of the pillars.
ordinarily employed. The intermediate winding gear and the click are
arranged upon this block and under the top plate, and the extra pieces
and screws required in the ordinary arrangement are dispensed with.
For the minute wheel I make a recess in the plate, leaving a strong
central pin in the said recess for the wheel to work upon, and I place
a bridge over the said minute wheel, which bridge I fix down by screws,
near to which screws the clutch wheel engages with the minute.
wheel.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Aaron Lufkin Dennison in the Great Seal Patent
Office on the 29th July 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, AARON
LUFKIN DENNISON, of Handsworth, in the County of Stafford, Watch
Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of February, in the year
of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Aaron Lufkin Dennison, Her special
licence that I, the said Aaron Lufkin Dennison, my executors, adminis-
trators, and assigns, or such others as I, the said Aaron Lufkin Dennison,
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 "IMPROVE-
MENTS IN WATCHES AND POCKET CHRONOMETERS," upon the condition (amongst
others) that I, the said Aaron Lufkin Dennison, my executors,

page_text: 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 Aaron Lufkin Dennison, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say :-
My Invention consists in constructing and arranging in the manner
herein-after described the parts of watches and pocket chronometers
whereby the working parts of the said watches and chronometers are
simplified and perfected, and the cases made air and water tight.
Watches and pocket chronometers made according to my Invention
require cleaning only at long intervals, and from the construction of the
cases are little liable to accidental injury.
I will describe my Invention with reference to a watch. In place of
the ordinary hinged bezel for holding the glass I employ a bezel having
a screw thread on its periphery, which screw thread takes into a corres-
ponding concave screw thread in the front dome of the case.
The glass
is burnished in the said bezel at a level below the top of the bezel, and
when the bezel is screwed into its place in the case the said case is closed
air and water tight. The thickness of the case required for the bezel
screw enables it to support the dome upon the bottom plate directly over
the pillars in the same, so that with a top plate thick enough to fill the
dome on the back or near side, the case of the watch has a much greater
strength than ordinary cases. I introduce the bezel and the movements
into the case from the back instead of from the front as usual. In securing
the back of the case in its place I dispense with a hinge, and connect it to
the case by a screw thread on its edge engaging with a corresponding
screw thread in the case. A button or thumb piece is provided for
facilitating the motion of the back in screwing and unscrewing.
In order more effectually to secure the air and water tight character
of the case, I make the winding arbor which passes through the stem of:
the pendant, and the push piece which passes through the edge of the

page_text: Figure 3 is the same view as Figure 1, with a portion of co
removed for the purpose of better exhibiting the winding mechanism.
Figure 4 is an elevation of the watch, with the top plate and winding
mechanism removed.
Figure 5 is a horizontal section of a portion of the watch taken on the
line a, Figure 1.
Figure 6 is a section of the spring barrel separately; and Figure 7 is a
separate view of the push piece for setting the hands.
The same letters of reference indicate the same parts in the several
Figures of the Drawings.
screw
b is the bezel holding the glass c, the said bezel having a
thread d on its periphery, which screw thread takes into a corresponding
concave screw thread in the front dome e of the case.
The said glass c
is burnished in the bezel b at a level below the top of the said bezel, as
represented in the Drawing. The bezel is introduced into the case from
the back, and when screwed in its place in the dome e it closes the front
of the case air and water tight. The back f of the case is connected to the
said case in a similar manner, that is to say, the said back f has a screw
thread 9 on its edge which engages with a corresponding screw thread in
the watch case, as seen in the Drawing. The screw threads may be in
part cut away so that in one position they may be pushed home and
locked by being partly rotated. By means of the button or thumb
piece the screwing and unscrewing of the back g may be readily
effected. The movements are introduced into the watch case from the
back thereof before the screwed back f is secured in its place. The
upper part of the winding arbor h is provided with a packing h², and the
part of the push piece for setting the hands is also provided with a
packing ; by means of these packings the said parts work air and water
tight. A depression ³ (see Figure 1) is made in the edge of the case
where the push piece i is situated, so as to prevent the said push piece
projecting beyond the edge of the case, as represented in the Drawing.
The push piece is composed of two rods or stems marked respectively i, iº,
The lower part of the push piece is furnished with a guide collar at **,

page_text: and the said push piece is raised out of action by the coiled spring *
situated around the stem of the part
.
of the said push piece. The
to the bottom of the recess in
forces the packing
One end of this spring
bears against the collar i*,
raising of the piece
which it is situated.
and the other end against the bottom of the recess made in the block v
and bottom plate of the watch for the push piece to work in. The
bottom of the part of the spring push piece operates upon the spring u.
of the clutch piece r, herein-after described..
on the
.
wheel /
The winding gearing consists of a bevilled toothed wheel k
winding arbor h and a toothed wheel 1, one part of the said
being composed of bevilled teeth and the other part of straight teeth. The
shape of the wheel is best seen in Figure 2. From an examination of
the said Figure 2 it will be seen that the bevilled teeth of the wheel /
gear with the bevilled wheel k on the winding arbor h, and the straight
teeth of the said wheel gear with the toothed wheel m on the spring
barrel n.
With the wheel m on the spring barrel n a click p engages
for preventing the running down of the said barrel; the said click is
furnished with two (or more) teeth of a shape proper to engage with the
teeth of the wheel m, as best seen in Figures 1 and 3. A spring p³
pressing upon the click p maintains it in gear with the wheel m. The
action of the click p in preventing the return motion of the spring
barrel will be readily understood by an examination of the Drawing.
The mechanism for setting the hands consists of a bevilled wheel q
made in one piece, with the clutch piece on the winding arbor h and
the minute wheel 8, the teeth of one-half of the said wheel 8 being
straight and the other half bevilled. The straight teeth of the wheel s
engage with the cannon pinion t on the arbor of the minute hand u³, and
the bevilled teeth of the said wheel & engage with the bevilled wheel q of
the clutch piece r. The way in which the pinion on the minute wheel s
gears with the toothed wheel on the arbor of the hour hand is seen in
Figure 2. The clutch piece r is situated on a square part of the winding
arbor h, and is capable of sliding thereon while the bevilled toothed
wheel k of the winding mechanism is situated upon a cylindrical part of
the said arbor (see Figure 2). By means of the spring u the clutch is
maintained in gear with the clutch on the bottom of the winding wheel k,
the wheel 9 on the said clutch being thrown out of gear with the
minute wheel s... On the rotation of the winding arbor h by its milled
r

page_text: head h³ rotation is given to the said wheel k, and through the wheels
and m to the spring barrel n, and the watch is wound up.
When the hands of the watch are to be set, the pusli piece i, i, at the
edge of the watch is pressed inwards; the clutch r is thereby withdrawn
from the clutch of the wheel k, and the wheel q on the said clutch is
made to gear with the bevilled part of the minute wheels, as represented
in Figure 4. By now turning the winding arbor h the hands of the
watch are set, no motion being communicated to the winding mechanism.
On removing the pressure from the push piece i, º, it resumes its normal
The 1
position by the action of its spring and the clutch spring u.
clutch is at the same time again thrown into gear with the winding
wheel k, as represented in Figures 1 and 2.
The parts of the mechanism for winding the watch and setting the
hands are arranged to work in a solid block v secured between the bottom
plate
Figure 5.
and top plate x of the watch, in the manner best seen in 1
2"
It will be seen by reference to the said Figure 5 that the winding
wheel (made in two pieces screwed together) works in a recess in the
block v, and that the bevilled wheels k and q and clutch work in a recess
partly made in the block v and partly in the bottom plate w,. the parts
occupying the said recesses with only sufficient freedom to allow of their
proper play. The click p also works upon a bub turned on the block v,
directly under one of the screws holding down the plate. The inner end
of the winding arbor is supported partly in the block v and partly in the
bottom plate io, see Figure 2. The block v serves in place of two of the
pillars ordinarily employed. The minute wheels works in a recess in
the bottom plate, the said wheel working upon a strong centrál pin in
the said recess, which pin is a part of the pillar or bottom plate w, a
bridge being placed over the said wheel. The push piece also works in a
recess in the block v (see Figure 4).
My improvements are applicable to pocket chronometers as well as to
watches, and the parts described and represented for making the case air
and water tight are applicable to ordinary watches and chronometers as
well as to keyless ones.
Having now described the nature of my Invention and the manner in
.

page_text: Lastly. Arranging the parts of the winding mechanism on or under
a solid block, for the purpose and substantially in the manner described
and illustrated in the accompanying Drawings.
In witness whereof, I, the said Aaron Lufkin Dennison, have here-
unto set my hand and seal, this Twenty-fifth day of July, in the
year of our Lord One thousand eight hundred and seventy-
AARON LUFKIN DENNISON. (L.S.)
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.