IMPROVE- MENTS IN COMPENSATING BALANCES FOR CHRONOMETERS, APPLICABLE ALSO TO OTHER TIME KEEPERS
Year: 1872

page_text: LETTERS PATENT to Edward Hawkins, of Warren Street, Fitzroy
Square, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN COMPENSATING BALANCES FOR CHRONOMETERS, APPLICABLE ALSO TO
OTHER TIME KEEPERS."
Sealed the 7th March 1873, and dated the 13th September 1872.
PROVISIONAL SPECIFICATION left by the said Edward Hawkins at the
Office of the Commissioners of Patents, with his Petition, on the
13th September 1872.
I, EDWARD HAWKINS, of Warren Street, Fitzroy Square, in the
County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN COMPENSATING BALANCES FOR CHRONOMETERS, APPLICABLE
ALSO TO OTHER TIME KEEPERS," to be as follows:-
This Invention relates to improved arrangements of parts for effecting
the correct compensation of expansion and contraction in balances for
chronometers and other time keepers, the compensation being effected in

page_text: the direction of the diameter of the balance, magnetic substances being
dispensed with when desirable.
The chief feature in this arrangement consists in placing straight
compensating bars in or near the diameter of the circle of oscillation,
which bars are not soldered or welded in the direction of their length to
other metals, whereby what is called a compound bar is made containing
a greater length for expansion and contraction than a radius of that
circle; the parts are arranged with screws and nuts or slides for
adjustment and with screws for adjusting the timing weights.
A similar arrangement of parts is applicable to the pendulums of
clocks and other time keepers.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Hawkins in the Great Seal Patent Office
on the 13th March 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HAWKINS, of Warren Street, Fitzroy Square, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of September, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Edward Hawkins, Her special licence
that I, the said Edward Hawkins, my executors, administrators, and
assigns, or such others as I, the said Edward Hawkins, my executors, ad-
ministrators, 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 COMPENSATING
BALANCES FOR CHRONOMETERS, APPLICABLE ALSO то OTHER TIME KEEPERS,"
upon the condition (amongst others) that I, the said Edward Hawkins,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe

page_text: 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 im-
mediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edward Hawkins, 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, that is to say:-
This Invention relates to improved arrangements of parts for effecting
the correct compensation of expansion and contraction in balances for
chronometers and other time keepers, the compensation being effected in
the direction of the diameter of the balance, magnetic substances being
dispensed with when desirable.
The chief feature in this arrangement consists in placing straight
compensating bars in or near the diameter of the circle of oscillation,
which bars are not soldered or welded in the direction of their length to
other metals, whereby what is called a compound bar is made containing
a greater length for expansion and contraction than a radius of that
circle; the parts are arranged with screws and nuts or slides for adjust-
ment, and with screws for adjusting the timing weight.
A similar arrangement of parts is applicable to the pendulums of
clocks and other time keepers.
In the constructing of a chronometer balance for ordinary use in
accordance with my improvements I prefer to make the radial arms of
steel, as also the timing bars, and for the compensating bars I employ
some largely expanding metal or alloy such as brass, as brass zinc, silver,
or aluminium, and by making these bars straight and placing them in the
same direction as the radial arms and longer than these latter, and not
being soldered, welded, or melted down upon them I leave them quité
as free as the radial arms, and any heat affecting the arms will likewise
operate on the compensator in the same manner (i.e.) in overcoming the
attraction of cohesion existing among its particles, and by using a metal
or alloy for the compensator, the ratio of expansion of which is a little in
excess of that of the radial arms and timing bars, I gain sufficient

page_text: "
Figure 1 shows the elevation of a chronometer balance constructed in
accordance with my improvements; Figure 2 is a similar view of the
reverse side; Figure 3 a plan and Figure 4 an under side view of
same; a is a hollow bar with radial arms a¹ to support or carry the
several parts of the balance; b, b, are bars carrying the timing weights
b¹, b¹; c, c, are compensator bars, each one being attached at one
extremity to one of the radial arms a¹ of the balance, the other ends
extending through the centre part; a has a screw cut on that part which
projects beyond it; this part of the bar being half round is combined with
one of the bars 6 having a similar screw, and likewise being only half
round, so that the nut d embraces both, and thus travels from the
extremity towards the centre of the balance for the purpose of adjusting
the proportions of the compensator to the other metals.
The parts may be placed one above the other, in which case Figure 3
would represent the elevation.
Figure 5 shows separate views of the bar or radial arms a, a¹,
consisting of a straight bar with a hollow central part a, the ends of
which may be turned up to support the other parts; the timing weights
although shewn spherical in the Drawing may be of any other shape, or
may form the periphery of the balance.
In constructing a pendulum in accordance with my improvements I
suspend it by a piece of watch spring from a button in the usual way to
avoid friction; from the watch spring a short iron or steel rod or wire
descends having a hole at its lower end through which passes a small
steel wire; this wire is double and reaches to the lower end of the

page_text: pendulum, where it is attached to a cross wire or a flanged button on
which rests the lower end of the compensator tube, or it may be fixed to
the compensator without any arm or button; the compensator proceeds
from this support nearly up to the spring before mentioned and there is
made to support the top end of the tube or timing bar which has a
screw adjustment at its lower end for timing, the nut of which is
embedded in a lead weight or bob as near its centre as convenient to
prevent the lead disturbing the effects of the compensator; the weight or
bob has a hole through its centre which allows of the passage of the
compensator to obtain sufficient length for the required purposes, and by
means of small screws and nails near the top of the pendulum I can so
arrange the proportions of the compensator to the other metals as to
obtain the greatest nicety of adjustment.
Figure 6 shows a pendulum constructed and arranged in accordance
with this part of my improvements. A is a spring and button by which
the pendulum is suspended as in the ordinary construction; B is a short
rod from which descends the small steel wire B* which is attached to the
button B' which supports the lower end of the compensator tube C
enclosed in a steel timing bar or tube D; this outer tube D is formed
with holes through it near the top for the adjustment screw E, a screw
being cut upon it at the other for carrying the weight or bob D²;
the compensator tube O in this arrangement is a zinc tube with holes
to correspond to those in the tube D to receive the screw and nut
adjustment E.
Having thus described the nature of my Invention and the manner
of performing or carrying the same into practice, I would have it
understood that I do not confine myself to the exact details herein
described so long as the novel features and character of my Invention
are retained, but what I claim is,-
-
First, the improved construction of compensating balances for
chronometers and other similar time keepers, substantially as herein-
before described and shewn in reference to Figures 1, 2, 3, 4, and 5 of
the Drawings hereunto annexed.

page_text: or other similar time keepers substantially as herein-before described
and shewn in reference to Figure 6 of the Drawings hereunto annexed.
In witness whereof, I, the said Edward Hawkins, have hereunto
set my hand and seal, this Eleventh day of March in the year
of our Lord One thousand eight hundred and seventy-three.
Witness,.
EDWARD HAWKINS. (L.s.)
J. G. TONGUE,
Patent Agent,
34, Southampton Buildings,
Chancery Lane,
W.C.