IMPROVE- MENTS IN TIME-PIECES
Year: 1882

page_text: LETTERS PATENT to Charles Denton Abel of No 28 Southampton Buildings
Chancery Lane in the County of Middlesex for an Invention of IMPROVE-
MENTS IN TIME-PIECES A communication to him from abroad by Franz
Reuleaux of Berlin in the German Empire.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at
the Office of the Commissioners of Patents on the 27th October 1882.
CHARLES DENTON ABEL of No. 28 Southampton Buildings Chancery Lane in
the County of Middlesex "IMPROVEMENTS IN TIME PIECES [A communication.
to him from abroad by Franz Reuleaux of Berlin in the German Empire.]
"
"
It is often desirable to compare the time at any place with the time at some
known meridian such as Greenwich, and which may be termed "general" time,
allowing for difference of longitudo. This invention relates to a time piece which
shows at once the mean "local" solar time at the place of observation and the mean
general" solar time at the meridian selected. For this purpose I provide the
time piece with two dials or sets of divisions, the one marked in the usual way up
to 12 hours with its hands indicating the local time at the place of observation,
and the other marked up to 24 hours, and its hands indicating the "general" time
at the meridian determined on. Both sets of hands are moved by the same works.
The latter hands being once set, will while the time piece goes correctly, shew the
mean time at the selected meridian reckoning from midnight onward 24 hours to
the following midnight, the minute hand making a revolution every hour as usual.
The former hands are made adjustable in the usual way so that they can be set to
the time of the place of observation. Obviously the two sets of hands and the
graduations for them may be concentric or separate on one plane or one set may
appear at one side and the other set at another side of the time piece or one set
may be arranged with its dial above the other. The invention is equally
applicable to stationary or portable time pieces and watches.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Denton Abel in the Great Seal Patent Office on the
25th April 1883.
CHARLES DENTON ABEL of No. 28 Southampton Buildings Chancery Lane in
the County of Middlesex. IMPROVEMENTS IN TIME PIECES A communication
to me from abroad by Franz Reuleaux of Berlin in the German Empire.
"
"
It is often desirable to compare local time with general time or to express
measures of local time in terms of general time. The object of this invention is
to facilitate these operations.
- By the term-general tine is to be understood the mean solar time at some
determined meridian, such as Greenwich, expressed in hours, minutes, etc., the hours
being reckoned from 0 to 24 from one midnight to the next. Local time on the
other hand is the mean solar time at some particular place expressed in hours,
minutes, elc., of equal duration with those of the general time, but with the hours
reckoned up to 12 from midnight to noon and from noon to midnight.
This invention relates to the construction of a time piece in which the general
and the local time can at once be read, it being provided with suitable divisions and
indices for that purpose. As zero meridian that of Greenwich recommends itself,
but by international agreement any other meridian might be selected.
For carrying into effect the intended object the time piece is provided with two
dials and two sets of indices, both moved by the same works. The indices for the
local time are arranged in the usual way, the minute hand revolving 12 times
during one revolution of the hour hand, that is to say, making one revolution
hourly. The indices for the general time, on the other hand, are arranged so that
the minute hand revolves once an hour, but its speed is to that of the hour hand
as 24 to 1, and there are divisions for 24 instead of 12 hours.
Both sets of indices are so arranged that they are driven by the same works,
but can be independently adjusted.
The indices for the general time being once set for the zero meridian, require no
adjustment if the time piece goes correctly. On the other hand, the indices for
the local time are set to the mean time of the place where the time piece is kept,
or of the habitation of its wearer.
The indices for the general time are actuated either directly from the arbor of
the minute hand for the local time, or from an arbor which is not directly geared
therewith, but is driven by the same works. The two dials may be concentric on
one plane or on opposite sides of the time piece, or one on a plane behind the
other; or. they may be eccentric on the same plane or on different planes, one
beside or above the other, or they may present themselves on surfaces inclined to
one another at any angle up to 180°. Striking gear may be connected to either or
both sets of indices.
When the general time piece is made as a watch for the pocket, I sometimes
arrange one of the dials inside the lid which may be fixed or made to open. In
the latter case the movement of the indices of the dial in question is interrupted
while the lid is open.
The accompanying drawing shews several constructions of time pieces for
indicating local and general time according to the before described invention,
Fig. 1 shews a watch having the ordinary dial A and hands B B' on the outer
face for indicating local time, while the dial C and hands D D' for indicating
general time are arranged on the inner back cover, the outer back cover E (which
may be of metal or glass) being broken away to show these parts. The axes

page_text: carrying the minute and hour hands, are geared to the corresponding spindles of
the clock work in the body of the watch by any known coupling that will permit
of the separation of the former from the latter on opening the cover C. The minute
land D of the dial C will revolve at the same speed as the minute hand B' of the
dial A, but the hour hand D of the former will, by any suitable known speed
reducing gearing, be made to revolve at half the speed of the hour hand B of the
dial A, that is to say, it will be geared with D¹ in the ratio of 1 to 24, while B
will be geared with B' in the ratio of 1 to 12.
Fig. 2 shews a construction in which the dial A for the local time is formed as
a small eccentric dial on the large dial C for the general time, in a similar manner
to the dial for the seconds hand on ordinary watches, the hands of A being geared
in the ordinary ratio of 12 to 1, while those of C are geared in the ratio of
24 to 1.
Fig. 3 shews a time piece in which the dial C for the general time is fixed or
formed on the face of the time piece, while the dial A for the local time is fixed,
concentrically to C on the glass cover of the timepiece, so that the hands D D',
geared in the ratio of 1 to 24, revolve behind the dial A, whose hands B B¹
geared in the ratio of 1 to 12 are carried by the extension of the arbor that carries
the minute hand D' of C.
Having thus described the nature of the said Invention and in what manner
the same is to be performed as communicated to me by my foreign correspondent,
I claim -
Constructing timepieces for indicating at once local and general time, wherein
there are two sets of indices actuated by one and the same clock work mechanism,
the one set having the minute and hour hands geared in the ratio of 21 to 1,
while the other set has them geared in the usual ratio of 12 to 1, and both having
their minute hand making one revolution hourly, the whole applied either to
stationary or portable time pieces.
In Witness whereof I the said Charles Denton Abel have hereunto set my
hand and seal this twenty fifth day of April in the year of our Lord Ono
thousand eight hundred and eighty-three.
CHA. D. AN
D. ADEL (L.)