CERTAIN IMPROVEMENTS IN CLOCKS, WATCHES, OR TIME- KEEPERS
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
HANSON, late of Huddersfield, in the County of York, but now of Clerkenwell,
in the County of Middlesex, Watchmaker, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Tenth day of October, in the ninth year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Charles
Hanson, Her especial license, full power, sole privilege and authority, that
I, the said Charles Hanson, my executors, administrators, and assigns, and
such others as I, the said Charles Hanson, my executors, administrators, or
assigns, should at any time agree with, and no others, from time to time
and at all times during the term of years therein mentioned, should and
lawfully might make, use, exercise, and vend, within England, Wales, and the
Town of Berwick-upon-Tweed, and in all Her Majesty's Colonies and Plan-
tations abroad, and in the Islands of Jersey, Guernsey, Alderney, Sark, and
Man, my Invention of "CERTAIN IMPROVEMENTS IN CLOCKS, WATCHES, OR TIME-
KEEPERS;" in which said Letters Patent is contained a proviso obliging me,
the said Charles Hanson, by an instrument in writing under my hand and
seal, particularly to describe and ascertain the nature of my said Invention,
and in what manner the same is to be performed, and to cause the same to
be enrolled in Her Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited
Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Hanson, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described
and ascertained in and by the following description thereof, reference being
had to the Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say):-
My Invention of Improvements in Clocks, Watches, or Timekeepers, refers
more particularly to that class of timekeepers called chronometers, which are
required to indicate the time with the greatest accuracy for astronomical and
nautical purposes, but my improvements may be also applied with advantage
to watches and clocks of the common construction. In the accompanying
Drawings I have shewn several views, which, together with the description
hereafter given, will enable any person conversant with such apparatus to
understand the nature and advantage of my Invention, which consists, firstly,
in a novel construction of detent for locking the teeth of the escapement
wheel; secondly, a modified construction of detent for the same purpose;
and thirdly, a mode of equalizing the impulse of the escapement wheel, so that
the main spring, whether at its greatest expansion or smallest contraction, will
always be made to give a regular impulse to the movements of the balance.
The novel construction of detent which forms the first head of my Invention
will be seen in elevation on an enlarged scale at Fig. 1. Fig. 2 is a plan
view as looking up from below, and Fig. 3 is a sectional plan of the detent
taken in the dotted line of Fig. 1. It is mounted vertically between the top
and bottom plates of the chronometer, and for that purpose is provided with
studs or centre pins a, a, at top and bottom. This detent is formed of a piece
of steel turned to a true cylinder at b; a portion of the shaft is cut away for
about two thirds of its diameter, thus forming a flat face for the purpose to be
hereafter described. The lower part of the detent is turned to a smaller dia-
meter, and receives upon it an arm or lever c, which is secured thereto.
Below this lever the shaft is cut away to nearly half its diameter, and made to
present a flat face d to the end of a spring e, which is fixed to the bottom
plate of the chronometer. The angle at which the flat faces 6 and d are formed
with regard to each other will be clearly seen at Fig. 2. The use of the
fixed spring e is to give the detent a tendency to assume one particular position,
so that after the detent has been acted on by the movement of the balance
staff or verge, it shall quickly return to its quiescent position, at which time the
end of the lever or arm c will point to the centre of the verge.
Figure 4 represents in elevation the balance shaft or verge, with the balance
wheel fat its upper end; and Fig. 5 is a plan view of the same, as seen from

page_text: below. Immediately under the balance f, and on the same shaft, the impulse
roller or pallett g is mounted. This pallett, as is well understood, is intended
to intercept the process of the teeth of the escape wheel (tooth by tooth) while
that wheel is being urged on by the action of the main spring. h is a smaller
cylinder placed on the balance shaft below the pallett g, and at its circumference
is provided with a projecting stud i, which acts upon the end of the lever c of
the detent, as will now be explained. By referring to Figs. 6 and 7, the
action of this part of the chronometer will be clearly seen.
Fig. 6 represents the verge, the detent, and the escapement wheel in eleva-
tion, and Fig. 7 shews them in plan view, the balance wheel being in dots, and
the detent being drawn in section the better to shew its action. Suppose the
balance wheel to be returning in the direction of the black arrow (Fig. 7), and
the teeth and 2 of the escapement wheel to be in the position shewn in the
Drawing, the stud i of the cylinder h will come in contact with the end of the
lever c, and force the detent round part of a revolution. The edge of the flat
face 6 of the detent will consequently be brought round to the tooth 2 of the
escapement wheel until it clears the point of that tooth and allows it to pass
on. The escapement wheel being thus released from its locked position the
tooth 1 will now fall upon the notch in the pallett g, and give an impulse to
the balance. By this means the pallett g will be caused to move round until
the tooth 1 has cleared the notch in that pallett, when the regulating spring
(not shewn in the Drawing), will reverse the motion of the balance shaft or
verge, as is well understood, and bring the stud i on the cylinder h again into
contact with the lever c, which lever immediately it was released from the
previous action of that stud i was brought into its quiescent position by the
stationary spring e pressing on the flat face d, at the lower part of the detent.
The return action of the balance, as indicated by the red arrow, will, through
the agency of the stud i, drive the detent lever in the opposite direction to that
which it formerly took when acted upon by the stud i, and thus allow the stud
i to pass it and assume a position on the other side of the lever c, where it is
ready (immediately upon the balance motion being reversed from that of the
red to the black) to strike again upon the detent lever and release the next
succeeding tooth of the escapement wheel from the locking of the detent, as
before explained. The continued action of the escapement being merely a
repetition of the movements already described, it will be unnecessary further
to trace the motions of the several parts.
I will now therefore proceed to explain the improved construction of detent
which forms the second head of my Invention. The detached views at Figs. 8
represent this improved detent, which, it will be seen, consists of a flat plate of

page_text: steel provided at its upper and lower ends with pivots a, a', by which it is
supported in the chronometer, and at its centre a portion is cut away to form
a notch or space b. Fig. 9 shews the detent, the verge, and escapement
wheel in elevation, and Fig. 10 is a plan view of the same. The pivots of
the detent are mounted in bearings so as to allow the detent to vibrate slightly,
and to rise and fall at stated intervals. Upon the lower end of the pivot a a
spring c presses, in order to keep the detent in its highest position. The
verge shaft, which carries the balance wheel and pallett g, as explained under
the first head of the Invention, has attached to it a small cylinder d, which is
provided on its under face with a raised portion or inclined plane e, see the
detached views Figs. 9*. f is an arm attached to the pivot a¹ of the detent.
The escape wheel is so placed that when the detent is at its lowest position,
the teeth of that wheel are free to pass through the notch b, but when the
detent is raised by the pressure of the spring c, the nearest tooth of the escape
wheel will come against the lower edge of the notch, and cause the detent to
lay flat against the side of the tooth.
I will now explain the action of this apparatus, premising that its effect is
exactly equivalent to the arrangement before described. Suppose the detent
to be in the position of the red lines of Fig. 9, that is, in the locking position,
and the verge to be moving in the direction of the red arrow Fig. 10, the
inclined plane e will, immediately it comes in contact with the arm f, force
down the detent, and release the tooth 1, which will now be free to pass
through the space b. The tooth (2) will then communicate an impulse to the
pallett g, and escape from the notch in that pallett; but before the tooth 1 has
time to pass the pallett, the spring c will have forced up the detent, and locked
the next succeeding tooth (say 3) of the escape wheel against the lower edge
of the notch b. In order to prevent the arm f from slipping on one side,
and escaping the action of the inclined plane e, a stud or stop h, rising from
the bottom plate of the chronometer, is provided, which will keep the arm fin
a proper position to be depressed. By this arrangement the locking of the
escapement is quickly and simply effected.
The third head of my Invention consists in the employment of a peculiarly
formed spring in place of the pallett g. This spring is represented in edge view
at Fig. 11, and side view at Fig. 12; but the better to explain its action, I
have shewn it as applied to my first-described detent at Fig. 18, which detent
may in this instance be placed in any convenient position to act upon the escape
wheel. A is the verge shaft, and to it the spring 9 is attached, so that it shall
follow the vibrations of the balance wheel. The end g¹ of this spring has an
inclination inwards, and rests against the verge shaft as shewn.
Now sup-
g

page_text: posing the tooth 1 of the escapement wheel to be just released from the detent,
the tooth 3 will come in contact with the end of the spring g, and drive it
forward, thus communicating to the balance an impulse which will always
be of the same power. Immediately the end of the spring has escaped the
tooth 3 of the escape wheel, it will fly back to its original position, and rest
against the verge shaft, and on the return motion of the balance the end g₁
will again be in its place to receive the impulse from the next succeeding
tooth 2, in the same manner as the notch in the before-mentioned pallett g.
By the employment of this spring 9 instead of the ordinary rigid pallett, I
am enabled to use a powerful main spring, which will have the effect of
overcoming the stiffness or clogging property of the oil when affected by
extreme cold, and yet at the same time allow of an undeviating impulse to the
balance.
Having now explained the nature of my Invention, and the manner of
carrying out the same, I wish it to be understood that I claim, under the
above in part recited Letters Patent,-
First, the novel construction of detent for locking the escapement wheel of
timekeepers, and also the mode of working the same, as exhibited at
Figs. 4 and 5.
Secondly, the construction and arrangement of locking apparatus, as shewn
at Figs. 9 and 10; and,
Thirdly, the application of a spring to the verge shaft in place of the
rigid pallett, as above described with reference to Fig. 13.
In witness whereof, I, the said Charles Hanson, have hereunto set my
hand and seal, this Ninth day of April, One thousand eight hundred
and fort
AND BE IT REMEMBERED, that on the same Ninth day of April, in
the year above mentioned, the aforesaid Charles Hanson came before our
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained, in form above written. And
also the Specification aforesaid was stampt according to the tenor of the
Statute in that case made and provided.
Enrolled the same Ninth day of April, in the year above written.