IMPROVEMENTS IN CHRONOMETER ESCAPE- MENTS
Year: 1876

page_text: LETTERS PATENT to Herbert John Haddan, of the Firm of Herbert and
Company, Patent Agents, of 67, Strand, in the City of Westminster, Civil
Engineer, for the Invention of "IMPROVEMENTS IN CHRONOMETER ESCAPE-
MENTS." A communication from abroad by F. Herman Voigt, of Buffalo, State
of New York. United States of America, Watchmaker.
PROVISIONAL SPECIFICATION loft by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 18th July 1876.
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Patent Agents,
of 67, Strand, in the City of Westminster, Civil Engineer, "IMPROVEMENTS IN
CHRONOMETER ESCAPEMENTS." A communication from abroad by F. Herman Voigt,
of Buffalo, State of New York, United States of America, Watchmaker.
My Invention consists in the combination with the chronometer and detend
levers of a watch movement of a disengaging spring lever, constructed and arranged
in such manner that said spring lever will engage said chronometer when revolving
with the balance in its forward movement, and thus cause the detend lever to liberate
the escape wheel, and when revolving in the opposite direction to avoid said
chronometer lever. This spring lever may consist either of a very elastic, straight,
or spiral blade spring, attached either to the lower side of the balance, or to a
separate roller placed upon the balance staff. It may furthermore be so arranged
that the detend lever will be placed above the table, and the chronometer lever
below the same, or vice versa, the action of said spring being the same in both
cases.
In order to insure proper engagement I provide the forward extremity of the said
spring with a nearly right angled bent, and arrange the same in relation to the
chronometer lever in such position that when the balance commences its forward
movement the projecting end of said spring will strike the front end of the
chronometer, and cause the same to describe a curve around its fulcrum, the
chronometer staff.
The curves described by said spring, and by the chronometer lever respectively
deviate, so that when the balance has made a revolution of about seven degrees the
parts will separate, and a hair spring placed on the chronometer staff cause this
lever to return to its normal position, while the balance continues its forward

page_text: movement. On its return stroke the spring will again come in contact with the
chronometer lever, but this lever being beveled the spring will deflect, and thus
avoid the said chronometer.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Herbert John Haddan in the Great Seal Patent Office on the 17th
January 1877.
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Patent Agents,
of 67, Strand, in the City of Westminster, Civil Engineer. "IMPROVEMENTS IN
CHRONOMETER ESCAPEMENTS." A communication from abroad by F. Herman Voigt,
of Buffalo, State of New York, United States of America, Watchmaker.
The object of my Invention is the production of a chronometer escapement for
watches and clocks, that shall, firstly, be less liable to derangement than those now
in use; secondly, disengage the escape wheel and chronometer with a quicker
motion, and within a smaller angle; thirdly, absorb less of the centrifugal force and
momentum of the balance; and thus, fourthly, cause a more perfect working of the
watch etc., in which it is used; fifthly, it shall start with the slightest vibration of
the balance, and shall not be stopped by sudden and severe shocks.
In the older and more recent styles of chronometers, the chronometer lever or its
equivalent is compelled to travel backwards a certain distance beyond its angle of
locking and unlocking, in order to pass the disengaging lever or its equivalent in the
return swing; this causes additional friction, and particularly an increase in fact
of the angle of locking and unlocking, which is a very serious drawback in such
devices. These and other obstacles are entirely avoided in my movement, on
account of the introduction of a disengaging lever made to recede to pass the
chronometer in the return swing.
To enable others skilled in the art to which my Invention appertains to make
and use the same, I shall proceed to describe its particulars of construction and
operation, and thereby refer to the annexed sheet of Drawings, in which,
Figure 1 is a plan showing the position of the parts at the moment when the
disengaging lever reaches the chronometer in the forward swing.
Fig. 2 is a similar plan illustrating the position when the escape wheel is
liberated, and the disengaging lever nearly leaving the chronometer, ny improve-
iments being applied to a modification of the device shown in Figure 1.
Fig. 3 is a longitudinal sectional elevation in line a, a, of Fig. 1.
Fig. 4 is a perspective view of the chronometer and part of the disengaging spring
lever.
This
A is the balance; B is its hub or nave; C is the escape wheel; D is the detent
lever secured to the staff D¹. Its bearing surface is a circular curve to keep the
escape wheel in perfect rest during the disengaging movement thereof; E is the
chronometer; F is the disengaging lever, consisting of a highly elastic spiral spring 4
secured to the collet F¹, placed upon the balance staff G below the table H.
spring is bent on its extremity, so that the projecting part thereof coincides with a
radial line of the table H, and this end has two guide pins F to keep it in proper
place. These guide pins may be placed either into the said table H, or into a
projecting arm of the collet FI; the latter arrangement being preferable on account
of its admitting of a ready adjustment of said disengaging lever; I is a jewel set
into the chronometer E; J is the table roller jewel, and da jewel in the detent;
K is a collet placed upon the chronometer staff D', and provided with a hair-
spring L; N is an adjusting screw to limit the movement of the chronometer; P is
an opening in the table roller to enable the observation of the action of the lever
points. This opening may also be made into the watch plate instead of the table
roller if desired.

page_text: The release of the detent, and through it the escape wheel, is effected by means
of the chronometer and disengaging spring lever in the usual manner, so that I
deem it superfluous to describe this part of the operation of my escapement, and I
will therefore refer only to the action of the disengaging spring lever in the return
swing of the balance; as soon as this lever reaches the chronometer it is caused to
recede in a radial line toward the centre of the balance staff, on account of the point
of said chronometer being beveled or tapering, but it will snap back to its original
position as soon as the chronometer point is passed. By this arrangement of the
spring lever F I am enabled to reduce the angle of locking and unlocking to a
minimum, so that the slightest vibration of the balance is sufficient to release the
escape wheel.
In its present location and construction I have reduced the angle of
locking and unlocking to five degrees, while after a swing of seven degrees of tho
balance the chronometer returns to its rest, and I derive therefrom the following
very important results:-1. The disengagement being accomplished within such a
small angle absorbs but a very small portion of the centrifugal force of the balance
while. 2, the movement will start with the slightest vibration; 3, the release lever F
being constructed to recede, and as soon as it has passed the chronometer rest to
snap back to its normal position, is at once ready for reaction. This avoids the
back motion of the detent, which is for many reasons objectionable and inadmissable.
The detent and chronometer are properly jewelled as shown in the Figures to reduce
friction.
From the nature of the parts entering into the construction of my improved
chronometer it is obvious that they may be easily duplicated by suitable machinery
and will cost less than any other first class chronometer. They may furthermore be
readily produced by any good watchmaker possessing ordinary facilities for
repairing watches, and can be substituted for other movements in old watches.
I am well aware that other more or less complicated mechanical devices may be
substituted for my spring lever F, such as a receding lever in the balance staff, etc.,
operated by a spring, cams, or similar means, or receding projections in the balance
hub or the table, or sliding devices upon the table, etc., or chronometer lever; or
that my spiral spring may be placed upon the chronometer to operate in conjunction
with a fixed release lever, all such as well as a straight spring secured to the rim of
the balance, and bent like my spiral spring point, are mechanical equivalents of my
receding spiral spring, and will answer the purpose more or less satisfactorily. I
have choosen, and give preference to my said spring as the simplest and best adapted
device to accomplish the object in view, viz., the construction of a release lever
capable of receding when passing the chronometer in the return swing of the
balance.
Having thus fully described my said Invention, I claim,―
In escapements for watches and clocks and other chronometric instruments, a
disengaging or release lever or its equivalent, constructed and arranged to recedo
when passing the chronometer lever or its equivalent in the return swing, sub-
stantially in the manner and for the use and purpose herein-before set forth and
described.
I also claim a disengaging or release lever or its equivalent, constructed and
arranged to recede when passing the chronometer lever or its equivalent in the
return swing, and to snap back to its normal or original position as soon as the
said chronometer is passed, substantially in the manner as and for tho use and
purpose stated.
In witness whereof, I, the said Herbert John Haddan, have hereunto set
my hand and seal, this Seventeenth day of January, in the year of our Lord
One thousand eight hundred and seventy-seven.
H. J. HADDAN. (L.S.)