IMPROVEMENTS IN CHRONOMETERS, CLOCKS, WATCHES, OR OTHER TIMEKEEPERS
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, wе, THOMAS
RESTELL, of Tooting, in the County of Surrey, Watch Maker, and RICHARD
CLARK, of the Strand, in the City of Westminster, Lamp Manufacturer, 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 Eleventh day of May, in the eleventh year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
Thomas Restell and Richard Clark, Her especial licence, full power, sole
privilege and authority, that we, the said Thomas Restell and Richard Clark,
our executors, administrators, and assigns, and such others as we, the said
Thomas Restell and Richard Clark, our 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, our Invention of "IMPROVEMENTS IN CHRONOMETERS,
CLOCKS, WATCHES, OR OTHER TIMEKEEPERS;" in which said Letters Patent is
contained a proviso obliging us, the said Thomas Restell and Richard Clark,
by an instrument in writing under our hands and seals, or under the hand and
seal of one of us, particularly to describe and ascertain the nature of our said
Invention, and in what manner the same is to be performed, and to cause
the same to be inrolled in Her Majesty's High Court of Chancery within six

page_text: 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.
NOW KNOW YE, that in compliance with the said proviso, we, the said
Thomas Restell and Richard Clark, do hereby declare that the nature of our
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):-
Our Improvements in Chronometers, Clocks, Watches, and other Time-1
keepers, relate,-
First, to various improved modes of constructing and arranging the escape-
ment part of clocks, watches, or other timekeepers, whereby, in some cases,
the use of the detent and lifting springs, and in others, the balance spring, as
well as the other parts connected therewith, are dispensed with, thereby
obviating the necessity, in some cases, of providing any compensation for such
parts, as in the usual construction of timekeepers is required.
Our Invention relates, secondly, to certain improved arrangements of com-
pensating balance springs and balances or pendulums, and in improved modeš
of constructing certain of the parts in connection therewith.
The third part of our improvements consists in an improved mode of
adapting musical boxes to clocks or timekeepers, in such a manner that the
box may be made to play at the proper intervals, as long as the clock
continues going, and without the necessity of winding up the musical part of
the apparatus, until the clock itself requires this operation.
Я
In the accompanying Drawings, we have shewn several modes of carrying
out the first part of our Invention. Fig. 1 represents a front view, and Fig. 2 a
side or edge view, of one-plan of making the escapement, in which the detent
spring, the lifting spring, and compensating balance are dispensed with, and in
place of adapting any compensation to the balance itself, as is usually the case,
the compensating arrangement. is adapted to the balance spring, which, as is
well known; becomes lengthened or shortened according to the variation of
the temperature; this part of the improvements will, however, be hereafter
more particularly explained under the second head of our Invention. In.
the arrangement of the several parts of the escapement shown in Figures 13
and 2, the centre of the balance wheel a, the escapement wheel b, and the
locking detent c, are all in a direct line. There is nothing. peculiar in the
construction of the pallet p, or of the escapement wheel 6, except that the latter
is made with an even number of teeth. The curve or face of the locking

page_text: detent must, however, be made in a particular manner, in order to operato
correctly. The manner of obtaining this curve or rather compound curve
will be best understood by referring to the Diagram, Figs. 3 and 3*. Let 1
be supposed to represent the centre of the escapement wheel, and the curve
from 2 to 3 (following the dotted lines) the path traversed by the extreme
edge of the teeth of the escapement wheel; the dotted line from 1 to 4 will
therefore represent the radius of the latter, and one half of the curve of the
detent will be concentric with the periphery of the escapement wheel; but
in order that the detent should be. made to lock .against the teeth of the
escapement, the remaining part of the curve is produced by shifting the centre
of the curve a little on one side of the escapement wheel, as shewn at 5; then
by striking a curve of the same radius in continuation of the first, the
second half of the curve will be brought inward, as seen at 6, and the
face of the detent will be made to consist of the compound curve shewn
in the Diagram. The back part of the detent may of course be made of
any convenient shape, as it does not affect the action of the escapement.
We find it most convenient to arrange the pallet p, escapement wheel b,
and detent c, in a right line; but a similar effect may be produced,
even when one or other of these parts are placed on one side; but as we are
not aware that any advantage can be obtained by so doing, we prefer arranging
them as shewn in the Drawing. The pivot of the detent c carries an arm or
lever d, the end of which is furnished with a ruby pin flat on one side and round
on the other; and the balance a is furnished with a thin spring e, one end
of which is fastened to the inside of the balance between the arms, and the
opposite end of this spring is bent outwards, and passes through and projects
from a hole or slot made in the periphery of the balance, as shown in Fig. 1.
It will now be seen that as the balance is going in the direction indicated by
the arrows in the Drawings, the point 7 of the springe will come against the
flat side of the ruby pin of the lever or arm d, and unlock the detent c, and
allow one tooth of the escapement wheel b to pass along the curve of the
detent; from the peculiar form of the curve of the detent, the tooth of the
escapement wheel will pass freely along one half of the curve, but imme-
diately that it passes the centre it will act against the second part of the curve,
and depress it, thereby lifting up the opposite side to its original position,
and causing it to lock against the following tooth. We would here observe,
that although we prefer that the face of the detent should be a com-
pound curve, such as that shewn in Figs. 1 and 3, yet it is not absolutely
necessary, as the second portion of it may bo flat, as shewn at Fig. 3*, and
even when thus made it will act satisfactorily. When the locking is completed
and the balance makes its return vibration, the point 7 of the spring strikes
C

page_text: against the round side of the ruby pin of the arm or lever d, and passes over
without affecting or unlocking the detent, which is shewn detached on an
enlarged scale at Fig. 1. In order to prevent confusion in the Drawing we
have not shewn any balance spring as applied to this escapement; it will,
however, be necessary to have one, and we prefer to employ our improved
compensating balance spring, hereafter described under the second head of our
improvements; but a balance spring and regulator of the ordinary description
may be employed, if preferred.
Fig. 4 is a plan view, and Fig. 5 a side or edge view, of another arrange-
ment of escapement. In this case, as in the other, the pallet p, the balance a,
the escapement wheel b, and the detent c, are all in a line; but in the present
instance the balance or pendulum spring is also dispensed with, as well as the
lifting and detent springs and compensating balance, and the balance at every
beat is made to describe exactly one revolution, and then stop until it receives
a second impulse, so that it will always rotate in one and the same direction.
In this instance the notch in the pallet p is cut to a curve corresponding with
the periphery of the escapement wheel, and the face of the detent c is formed
of a compound curve, or partly of a curve and partly flat, as in the former
instance, but with the addition of a bauking piece 8, which is mounted on the
top of one side of the detent. The corner 9 of the detent, and against which
part the teeth of the escapement wheel lock, is also bevilled, or cut off at an
angle for the purpose hereafter explained, as shown in the enlarged detached
view of the detent, Fig. 2. The axle or pivot of the detent carries a small
tappet or pallet i, against which a pin or stud 9, on one of the arms of
the balance acts. Another stud or pin his fixed in the under side of the
periphery of the balance, and when the balance is in a quiescent position this
pin rests against a spring piece j. Let us now suppose that the balance has
received an impulse, the pin h will force back the spring j into the position
shewn by dots in the Figure, and the balance will continue its rotation until
the pin h again comes against the spring j, by which it will be stopped sud-
denly. At the same time the other pin g, on the arm of the balance, strikes
against the tappet or pallet i of the detent, and will force it back just enough
to liberate the escapement tooth from the locking; then the extreme edge of
this tooth will act against the angle or bevil at the corner of the detent at 9,
and will force it further back so as to bring the bauking piece 8 on the
detent behind the pin h, and prevent it from returning, then the escapement
tooth will pass along the face of the detent, which, being made like the detent
in the former case, will thereby be depressed on that side, and the opposite
side 9 brought back into its original position so as to lock the next tooth of
the escapement wheel. The impulse is given to the balance by the teeth

page_text: on the opposite side of the escapement wheel striking into the notch of and
forcing forward the pallet p. In order to make the motion of the 'balance
uniform, we place on two of the arms thereof two small fans or flyers k,
which, being made moveable along the arms of the balance, enable us to
regulate the timekeeper.
Fig. 6 represents a front elevation, and Fig. 7 a side or edge view, of an
escapement, of somewhat similar construction to those already described;
applied to a clock or timepiece furnished with a pendulum. The detent c
is constructed and acted upon in a similar manner to that shewn in Figures 1
and 2. a is the pendulum, which is á compensating one, and will be hereafter
more particularly described under the second head of our improvements. bis
the escapement wheel; c, the detent; and d, the detent arm or lever, which is
furnished at its upper end with a ruby pin. e is a spring or lever attached to
the back part of the pendulum for the purpose of acting upon the detent
arm d, precisely in the same nianner as that shewn at Fig. 1. In the Drawing
Fig. 6, the several parts are represented in the position they would assume
when the pendulum is in the act of returning, and has just. unlocked' the
escapement wheel, which is then about to move forward in the direction of
the arrow.
In doing this it will, by means of one of its upper teeth acting
against the pallet p, give an impulse to the pendulum in the direction in
which it is going, and at the same time the tooth at the lower side which has
just been unlocked will also advance, and by striking against the raised side of
the detent will move the same back again, and cause the opposite side thereof
to lock against the succeeding tooth of the escapement wheel. In this
arrangement the pendulum is never resting on the escapement wheel, and-is
never in contact with it except when the escapement is unlocked from the
detent, and one of the upper teeth of the escapement wheel is allowed to act
against the pallet p, to give the impulse at the, moment when the pendulum is
going in the same direction, as indicated by the arrows in the Drawing;. by
this means a considerable amount of friction and wear is avoided.
Our improved method of lengthening or shortening balance springs, to correct
the expansion or contraction occasioned by changes of temperature, isishewn in
the several Figures in Sheet II. of the Drawings: Fig: 8 is a plan' view of
the simplest and most convenient arrangement for effecting this object.. d.is
the balance; s, the balance spring, the inner end of which is as usual connected
to the axis of the balance, and its outer end to the curved arm of a T-shaped
lever 1, the opposite end of which lever has another curved arm.*, which. we
prefer to have graduated; this curve should be struck from the centre of the
pivot of the brass, or other metal arm m, which is secured firmly to the upper
plate of the watch or chronometer by a screw n, in such a manner that when

page_text: required the arm may be moved to the right or left after the screw n is slightly
loosened. The action of this compensating arrangement is as follows:-
Supposing by an increase of temperature the balance spring should elongate,
the arm m will also elongate, and by acting against the inner side of the
curved arm of the lever 1, near its fulcrum, will force the graduated arm 1*
back, and thereby draw back the opposite end of the lever 1, and thus take up
a proportionate length of the balance spring according to the amount the latter
shall have become elongated. If, however, upon trial it should be found that
the bar m by its expansion causes the lever to take up too much of the
balance spring, then the screw n must be loosened and the arm m moved
farther from the fulcrum of the lever la sufficient distance to correct the error.
Of course, if, on the other hand, the arm m does not expand sufficiently to
correct the error produced by the elongation of the balance spring, then it
must be moved nearer to the fulcrum of the lever l, but care must be taken
after every time that the arm m is altered in position that it should be properly
and firmly secured to the plate by tightly screwing up the screw n, so as to
render the arm m immovable laterally.
Fig. 9 is a modification of the above, the only variation being that the
lever is somewhat different in form, and the arm m is placed in a different
position. It operates, however, in precisely the same manner, and will be
perfectly understood without any further description, and upon merely referring
to the Drawing.
Fig. 10 is another modification, in which, instead of the metal arm m, a
glass tube, containing mercury and a small steel piston, are employed. The
glass tube should be about half filled with mercury, and then the steel
piston is to be placed therein. The tube must then be screwed down
to the plate, as in the former instance, and it will be found to act in the
same manner, except that mercury, being more sensitive to changes of tem-
perature than other metals, will act more delicately and to a greater amount.
In employing mercury it is necessary to be careful to prevent any portion of
the mercury escaping from the tube; therefore, when the tube is detached from
the watch or chronometer for any necessary purpose, the steel piston should
not be taken out of the tube; and in order to prevent the piston from being
accidentally removed, we secure it therein by means of the small screw o. The
other small screwj, at the opposite end of the tube, is merely to allow the air
to escape therefrom when the mercury is poured in; and when the proper
quantity of mercury and the steel piston are placed in the tube, the hole at
the inner end is stopped by the screw j, and the screw o, which holds the
steel piston, must be then loosened, in order to allow the piston to have full
play.

page_text: Fig. 11 is a modification of the above plan, mercury being also employed in
conjunction with a steel piston. In this case the glass tube is curved, and the
steel piston must also be made of a corresponding figure. The tube is
screwed down at both ends to the upper plate, and the outer end of the
balance springs (it will be seen) is attached in some convenient and suitable
manner to the outer end of the piston, so that, as the mercury in the tube
expands, it will force out the steel piston, and thereby draw back the balance
spring which is attached to it. Two of the arms of the balance in this Figure.
are furnished with small fans or flyers k, for the purpose of regulating the
velocity of the balance, as already described in reference to Fig. 4. In
Figures 6 and 7 we have shewn two views of our improved compensating
pendulum. Fig. 6 represents the pendulum in front elevation; and Fig. 7, in
longitudinal vertical section. The pendulum is composed of two metal bars,
one of brass, and one of steel; and those parts of the two bars which effect
the compensation are in the proportion of five of brass to three of steel. In
the sectional view, Fig. 7, q represents the brass bar, which is behind the steel
one r. These two bars are connected together at their upper ends by a
screw t, a small plate or disc being placed between them. A small pulley u
is mounted at the lower end of the compensating part of the steel bar, and the
remaining portion of the bar below this point does not affect the compensation,
and only serves as a guide to the bob, which is suspended on the lower end of
the steel bar by a chain v, connected at one end to the metal bob by a regu-
lating screw w, whereby the mean time may be obtained after the two bars
are properly adjusted for compensation. The chain v, after passing over the
pulley u, and through a hole made in the brass bar q, descends to the lower
end thereof, to which it is attached in any convenient manner. The upper
end of the steel barr is furnished with a number of plain holes; and the brass
bar has also a number of holes which are tapped to receive the screw t, by
which the two bars are connected together. These holes admit of the two bars
being properly adjusted with exactness, the regulating screw w being merely
employed to bring the clock to mean time when the compensating part of the
pendulum is properly adjusted, as before stated.
g
Figures 12, 13, and 14 represent our improved method of adapting musical
boxes to clocks, whether constructed according to our improvements or in the
ordinary manner. By our improvements the musical apparatus is made to
play immediately before the hour is struck, and it will continue to play a
certain length of time every hour, as long as the clock is wound up. Fig. 12
is a front view of the apparatus; Fig. 13 a side or edge view, and Fig. 14 a
partial plan view, of the upper part. a is a wheel which forms part of the
clock movement, and makes exactly one revolution in an hour. The axle of

page_text: this wheel carries an arm b, which, just before the termination of every hour,
strikes against the lower end of a short arm c, of a double-armed lever d,
the longer arm of which carries a pin that works in a slot made in the end
of another lever e. This levere has its fulcrum at f, and its upper end,
when the musical apparatus is not working, is in contact with the flyer of the
musical apparatus, which is prevented from working until this end of the
lever a is removed. The lever e also carries a small pin or stud 1, which,
when the apparatus is in a quiescent state, remaius in a notch made in a
groove at one end of the barrel k of the musical apparatus.
Having thus briefly described the principal parts which connect the clock
movement to the musical apparatus, we will now proceed to explain tho
operation of the various parts.
When the arm b of the wheel a strikes against and lifts up the short arm c
of the double lever d, the latter, by means of a pin at its opposite end, acts
against the lower end of the lever o, and withdraws the upper end thereof
from the flyer of the musical apparatus, which immediately begins to work; at
the same time the pin or stud 1 has been partially lifted out of the notch of
the groove at the end of the barrel k of the musical apparatus; and
as this barrel begins to rotate by the action of the weight at its
opposite end, the pin 1 will be forced further back into the annular
part of the groove, where it will remain all the while the barrel con-
tinues to rotate and the music to play. Immediately, however, that the
notch comes round again, the pin drops in and the upper end of the lever e
will rise and stop the flyer, and consequently the musical apparatus will cease
playing. It is necessary, however, to prevent the striking apparatus from
sounding the hours until the music has ceased playing, and this is effected by
means of an arm g, projecting from the lever d, which arm prevents the pin
of the ordinary warning wheel h from rotating, and consequently stops the
striking apparatus until it is removed. It should be observed that the lever d
carries a pin 2, which lifts up the ratchet lever i, and permits the rack j to
fly back in the usual manner, leaving the striking apparatus ready to sound
the hour immediately that the pin of the warning wheel is freed from the
arm g of the lever d, which event takes place when the levers d and e are
allowed to descend into their original position by the pin 1, on the lever c
falling into the notch at the end of the musical barrel k. It will be evident
that the arm of the wheel a will have passed by the end of the short lever c,
and consequently will present no obstacle to the two levers d and e and the
other parts returning to their original position.
Having now described our various improvements, and the best means with
which we are acquainted for carrying the same into effect, we would observe,

page_text: A
in conclusion, that although in order the more clearly to explain the nature
and object of our improvements we have considered it necessary to describe
and shew certain parts of timekeepers which have been before known and in
use; yet we do not by any means intend to claim such parts as forming parts
of our improvements. But that which we consider to be new, and therefore
wish to claim as the Invention secured to us by our herein-before in part
recited Letters Patent, is,-
First, the arrangement or construction of escapements for watches, clocks,.
chronometers, or timekeepers herein shewn and described, particularly placing
the balance, the escapement wheel, and detent in a line, and also the peculiar
manner of constructing and working the detent, or any mere modification
thereof, whereby the same or a similar effect may be produced.
Second, we claim the method of compensating the variations of balance or
pendulum springs, by means of a metal rod or rods or bars, which may be
made to take up any excess or give out for any decrease in the length of the
spring arising from variations in temperature, as above set forth. We claim
also the method herein shewn of constructing compensating pendulums.
Third, we claim the method herein shewn of adapting musical boxes or
apparatus to clocks or timekeepers..
In witness whereof, we, the said Thomas Restell and Richard Clark
have hereunto set our hands and seals, this Eleventh day of November,
in the year of our Lord One thousand eight hundred and forty-eight.