Improvements in or relating to Escapement Mechanism for Watches and Clocks.
Year: 1897

page_text: Date of Application, 25th Mar., 1897
Complete Specification Left, 22nd Dec., 1897-Accepted, 25th Mar., 1898
PROVISIONAL SPECIFICATION.
Improvements in or relating to Escapement Mechanism for Watches
and Clocks.
I, EDMOND PERDRIZET. of Bethoncourt (Dep. du Doubs), in the Republic of
France, Manufacturer, do hereby declare the nature of this invention to be as
follows:-
The present invention relates to a watch or clock-mechanism and has for its
object a free lever-escapement with a safety disc and a guard spring; whereby
irregularities of movement and of the regulating mechanism, as well as difficulties
of construction which are characteristic faults of the escapement systems now in
use, are avoided.
The escapement mechanism according to the present invention presents the
following characteristic features.
1. It is not placed on the spindle, whereby all irregularities of movement and
regulating are avoided.
2. The impulse to the balance is produced by pins on the escape wheel, which act
on a pallet on the balance spindle.
3. The distance between the balance spindle and the spindle of the escape wheel
is not a fixed one unlike in other systems now in use where this distance is
invariable.
4. The distance between the balance spindle and the spindle of the escape wheel
is considerably reduced, thus making the disengaging motion shorter, so that the
friction of the parts is smaller.
5. The large disc necessary for a spring-escapement is dispensed with.
6. The contact of the teeth with the book of the spring-escapement is replaced
by contact with a pin which produces a much slighter shock.
These different characteristic features of the escapement according to the present
invention, enable an easily-regulated apparatus of very great uniformity to be
constructed in a very simple and cheap manner.
On the balance-spindle are mounted two fingers or pallets as well as a safety
dise which will be hereinafter fully described. One finger effects the movement
of the escape lever pivotted on its spindle. On the same spindle is placed a spring
which is held to the end of the lever by a pin. On the lever also acts a
spring. The lever has a projection against which the teeth of the escapement
wheel strike. Said wheel actuated from the barrel as in ordinary watches has on
its periphery six or twelve teeth according to whether the watch marks only seconds
or half-seconds. On one of its faces the escapement wheel has the same number
of pins as teeth, with which engages, during the movement of the escapement wheel
a second pallet on the balance-spindle. The escape-mechanism consists only of
these parts.
The operation of the device is as follows:-
The balance having been caused to move, the pallet acts upon and moves the
lever spring and with it the lever. The tooth is thus released from the lever catch

page_text: and the wheel driven by its spring, turns until the next pin strikes against the
other pallet and causes it to move, thus restoring to the balance the force that it
has expended. Then the lever. which in its movement had caused its spring to
bend is brought by the latter back into its original position, the return movement
of said lever being limited by a stop or pin which regulates the extent of engage-
ment of the lever catch with the teeth of the escape wheel. Then the next tooth
of the escapement wheel strikes against the projection of the lever. At the same
time that this movement takes place, the balance is brought back by its spring,
the lever operating finger passes over the lever spring and resumes its original
position, and the same movements are repeated. As has been mentioned before,
on the balance-spindle is mounted a safety-disc which is used to prevent the lever
from moving outside its usual limits and from allowing a tooth of the wheel to
escape accidentally, as from a shock. Against this disc rests an extension of the
lever. This extension stops the lever when it has a tendency to return back, the
disc being provided with a notch to allow the passage of the extension of the lever
during the rotation of the disc.
The escapement is provided with a guard formed by a spring on which acts a
pin fixed under the safety-disc. This pin acts on the spring, and the whole strikes
at each rotation against stop pins fixed on the plate one on each side of the
spring. The use of this guard has no drawbacks, for its operation being uniform
it does not affect regulating; its purpose being to prevent over-banking when the
escapement works.
Dated this 25th day of March 1897
EDMOND PERDRIZET.
Boult & Wade,
Agents for the Applicant.
Improvements in or relating to Escapement Mechanism for Watches
and Clocks.
I, EDMOND PERDRIZET, of Bethoncourt (Dep. du Doubs), in the Republic of
France, Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:―
The present invention relates to a watch or clock mechanism and has for its
object à free lever-escapement with a safety disc and a guard spring whereby
irregularities of movement and of the regulating mechanism as well as difficulties
of construction which are characteristic faults of the escapement systems now in
use are avoided.
The escapement mechanism according to the present invention presents the
following characteristic features.
1. It is not placed on the balance-spindle whereby all irregularities of movement
and regulating are avoided.
2. The impulse to the balance is produced by pins on the escape wheel which
act on a pallet on the balance spindle.
3. The distance between the balance spindle and the spindle of the escape wheel
is not a fixed one unlike in other systems now in use where this distance is
invariable.
4. The distance between the balance spindle and the spindle of the escape wheel
is considerably reduced, thus making the disengaging motion shorter so that the
friction of the parts is smaller.

page_text: 5. The large disc necessary for a spring-escapement is dispensed with.
6. The contact of the teeth with the hook of the spring escapement is replaced
by contact with a pin which produces a much slighter shock.
These different characteristic features of the escapement according to the present
invention enable an easily-regulated apparatus of very great uniformity to be con-
structed in a very simple and cheap manner.
In the accompanying drawing Fig. 1 shows a general view of the mechanism.
Figs. 2 and 3 show different positions of the balance relatively to the escapement
wheel.
Fig. 4 is a plan of the escapement mechanism.
On the balance spindle are mounted two fingers or pallets A and B as well as a
safety disc C which will be hereinafter fully described. One finger A effects the
movement of the escape lever D pivotted on its spindle E. On the same spindle
is placed a spring F which is held to the end of the lever by a pin G. On the
lever D also acts a spring H. The lever has a projection D₁ against which
the teeth K of the escapement wheel L strike. Said wheel being actuated from the
barrel as in ordinary watches (Fig. 1) and has on its periphery 6 or 12 teeth K
according to whether the watch marks only seconds or half seconds. On one of
its faces the escapement wheel L has the same number of pins M as teeth with
which engages, during the movement of the escapement wheel, a second pallet B
on the balance spindle. The escape mechanism consists only of these parts.
The operation of the device is as follows;-
The balance having been caused to move in the direction indicated by the arrow
(Figs. 2 and 3) the pallet A acts upon and moves the lever spring F and with it
the lever D. The tooth K is thus released from the lever catch D₁ and the wheel L
driven by its spring turns in the direction indicated by the arrow until the next
pin M strikes against the pallet B and causes it to move thus restoring to the
balance the force that it has expended. Then the lever D which in its movement
had caused its spring H to bend is brought by the latter back into its original
position, the return movement of said lever being limited by stop or pin O which
regulates the extent of engagement of the lever catch with the teeth of the escape
wheel. Then the next tooth of the escapement wheel L strikes against the
projection D of the lever. At the same time that this movement takes place, the
balance is brought back by its spring, the lever operating finger A passes over
the lever spring F and resumes its original position, and the same movements are
repeated. As has been mentioned before on the balance spindle is mounted a
safety disc C which is used to prevent the lever 1) from moving outside its usual
limits and from allowing a tooth K of the wheel L to escape accidentally as from
a shock. Against this disc rests an extension P of the lever D. This extension
stops the lever when it has a tendency to return back, the disc being provided with
a notch R to allow the passage of the extension P of the lever I during the rota-
tion of the disc.
The escapement is provided with a guard formed by a spring S on which acts
a pin T fixed under the safety disc C. This pin acts on the spring and the whole
strikes at each rotation against stop pins V fixed on the plate one on each side of
the spring. The use of this guard has no drawbacks, for its operation being uniform
it does not affect regulating its purpose being to prevent overbanking when the
escapement works.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. An escapement mechanism for watches or clocks characterised by the move-
ment of the escape wheel being regulated by a spring controlled lever and two
pallets mounted on the balance spindle one of which transmits the movement of
the escapement wheel to the balance and the other the movement of the balance
to the lever substantially as described.

page_text: 2. In mechanism of the character described a safety disc provided with a notch
with which engages a continuation of the balance lever preventing any movement
of the latter outside the usual limits substantially as described.
3. In mechanism of the character described a spring forming a guard acting on
a pin on the safety disc to prevent overbanking substantially as described.
Dated this 20th day of December 1897.
BOULT & WADE,
Agents for the Applicant.