Improvements in Escapements for Pendulum Clocks.
Year: 1894

page_text: Date of Application, 16th July, 1894
Complete Specification Left, 11th Apr., 1895-Accepted, 24th May, 1895
PROVISIONAL SPECIFICATION.
Improvements in Escapements for Pendulum Clocks.
I, BENJAMIN JOSEPH BARNARD MILLS, of 23 Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention
(a communication to me from La Société Anonyme pour l'Exploitation des
Brevets Dardenne, of 10 Petite Rue des Longs Chariots, Brussels, in the Kingdom
of Belgium) to be as follows:-
In pendulum clocks the escapement lever (anchor) is always connected to the
pendulum in such a manner as to cause it to follow rigorously the movements
imparted to it by the vibrations of the latter; in other words the escapement lever
(anchor) is prevented from making any movement independent of the pendulum,
or, in still clearer language, its movements are directly imparted to it by the
pendulum. The result is that all irregularities inherent in the movement of the
pendulum are necessarily communicated to the anchor and through it to
the escapement wheel, thereby compromising the regularity of the motion which
it receives from the driving power. This is all the more obvious from the fact
that at each beat of the pendulum the engaged pallet of the escapement lever
(anchor) is constantly in motion during the whole time it is entering and leaving
the teeth of the escape wheel, as a result of which the periodical stoppage of the
latter has not a sufficient exactitude to secure an absolute precision, the periods for
engagement and disengagement of the escapement being moreover affected by the
irregularities of the oscillatory movement of the pendulum.
The arrangement forming the subject of the present invention obviates the
before mentioned inconveniences through the particular manner of connecting
the pendulum to the escapement, whereby at every two successive beats of the
pendulum, one of the pallets of the escapement lever (anchor) shall stop the
escapement wheel in complete independence of the pendulum for a definite and
invariable period, during which the pendulum is allowed to finish its beat in full
liberty, whilst on the return beat the other pallet of the anchor shall stop the
escapement wheel in the ordinary way and receive from the latter a fresh impulse
to recommence its motion.
The result of this arrangement is to obtain for each complete vibration of the
pendulum an invariable time for stopping and only a single impulse which is quite
sufficient as during the next beat the pendulum regains enough force through its
partial disconnection from the escapement lever (anchor) to enable it to accomplish
its return beat.
The escapement lever, supposed to be an anchor in the present instance, is not
arranged above the escapenient wheel, but at its side, where it oscillates freely on
its centre of motion. From its centre extends horizontally a screw threaded lever,
upon which is screwed a tapped counterpoise, which determines the fall of the
upper pallet as soon as it is left to itself, that is to say, disengaged from the
pendulum. At the centre of the escapement lever (auchor, is fixed, in addition to
the counterpoise lever, au arm which extends downwards, either vertically or in a
position more or less inclined from the vertical, but always so that an action

page_text: exerted, by reason of the direction of the arm, in contrary direction to that of the
counterpoise lever, shall always be overcome by the latter and cannot prevent the
fall of the upper pallet as soon as the escapement lever (anchor) is liberated.
The downwardly extending arm takes the place of the old fork to effect
connection between the escapement lever (anchor) and the pendulum, but not in the
old invariable and permanent manner, but in an adjustable and temporary manner,
so that at a given moment the escapement lever (anchor) shall find itself solely
under the influence of the counterpoise and that the pendulum shall complete its
Imotion in full liberty.
For this purpose the lower extremity of the said arm should be connected to
the pendulum by means of a membrane effecting at the required times the said
connection and disengagement of the two parts, and the membrane enabling these
two functions to be realized in the most simple manner, is a flexible connection,
preferably a cord, capable of being lengthened or shortened at will to obtain the
exact adjustment between the escapement lever (anchor) and the pendulum by a
stud turning with sufficient friction in the lower end of the arm and upon which
the cord is wound.
The adjustment being arranged between the escapement lever (anchor) and the
pendulum, the regulation of the entire system is effected by shifting the counter-
poise upon the lever, and it will be readily understood that by this agency there is
obtained a much more precise regulation than by the simple displacement of the
bob of the pendulum.
In effect, the speed of the escapement lever (anchor) will no longer depend only
on the length of the pendulum, so that, no matter what position of the bob, the
speed can always be regulated by means of the counterpoise in such manner that
cach motion corresponds always exactly with the passage of one tooth of the
wheel in the desired time, and at the fraction of motion during which the pendulum
vibrates freely and the wheel is stopped.
The working of this escapement can be readily understood from the preceding
description.
The pendulum having accomplished its full motion towards the right, the lower
pallet of the escapement lever (anchor) stops the wheel in the ordinary manner;
then, in commencing its beat towards the left, the tooth pressing against the pallet,
gives impulse to the system in the known manner to drive it towards the left, in
which motion it is again assisted by the counterpoise of the escapement lever as
the flexible membrane or cord is distended, that is to say, that the pendulum and
the escapement lever (anchor) are connected together.
This state of rigidity is maintained to, about half of the beat of the pendulum,
which is then in its vertical position. About this moment the upper pallet of the
escapement lever (anchor) commences to touch the inclined face of the corresponding
tooth, and from this moment it no longer follows the pendulum, which continues its
beat, slackening the flexible membrane, whilst the counterpoise effects the fall of
the upper pallet, which then invariably stops the wheel during the period in which
the pendulum completes its beat towards the left and returns to again distend the
membrane, raise the upper pallet, and recommence the same motions.
It will be remarked that by this agency the wheel is stopped at each second
tooth, or for one entire vibration of the pendulum, during a constant and invariable
period, so that it is of little consequence that the stoppage of the intermediate tooth
is more or less constant or is subject to the eventual irregularities of the pendulum,
the independent stoppage of the second tooth always correcting them in an
inevitable manner upon the entire vibration, so that the speed of oscillation is
suitably regulated with relation to the rotation of the wheel; the working of the
clock will be of an absolute precision.
This precision can further be increased if there is combined with the
arrangement above described an automatic winding apparatus consisting of a
pneumatic fan or turbine working so as to maintain the weight at about the same
height, or the spring at constant tension if this latter motive power is used instead

page_text: of a weight. The drum of this turbine can be connected with a draft flue or
otherwise be exposed to the action of a constant current of air which operates it.
Dated this 16th day of July. 1894.
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.
Improvements in Escapements for Pendulum Clocks.
1, BENJAMIN JOSEPH BARNARD MILLS, of 23 Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention
(a communication to me from La Société Anonyme pour l'Exploitation des Brevets
Dardenne, of 10 Petite Rue des Longs Chariots, Brussels, in the Kingdom of
Belgium,) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
In pendulum clocks the escapement lever (anchor) is always connected to the
pendulum in such a manner as to cause it to follow rigorously the movements
imparted to it by the vibrations of the latter; in other words the escapement lever
(anchor) is prevented from making any movement independent of the pendulum,
or, in still clearer language, its movements are directly imparted to it by the
pendulum. The result is that all irregularities inherent in the movement of the
pendulum are necessarily communicated to the anchor and through it to
the escapement wheel, thereby compromising the regularity of the motion which
the said wheel receives from the driving power. This is all the more obvious
from the fact that at each beat of the pendulum, the engaged pallet of the
escapement lever (anchor) is constantly in motion during the whole time it is
entering and leaving the teeth of the escape wheel, as a result of which the
periodical stoppage of the latter has not a sufficient exactitude to secure
absolute precision, the periods for engagement and disengagement of the escape-
ment being moreover affected by the irregularities of the oscillatory movement of
the pendulum.
an
The arrangement forming the subject of the present invention obviates the
before mentioned inconveniences through the particular manner of connecting
the pendulum to the escapement, whereby at every two successive beats of the
pendulum, one of the pallets of the escapement lever (anchor) shall stop the
escapement wheel in complete independence of the pendulum for a defiuite and
invariable period, during which the pendulum is allowed to finish its beat also in
full liberty, whilst on the return beat the other pallet of the anchor shall stop the
escapement wheel in the ordinary way and receive from the latter a fresh impulse
to recommence its motion.
The result of this arrangement is to obtain for each complete vibration of the
pendulum, an invariable time for stopping and only a single impulse, which is quite
sufficient as during the next beat the pendulum regains enough force, through its
partial disconnection from the escapement lever (anchor), to enable it to accomplish
its full beat in the opposite direction.
The invention is illustrated in the accompanying drawings, in which :-
Fig. 1 is a front elevation of the escapement showing the invariable position of
stoppage.
Fig. 2 shows the same in the position of impulse.
Fig. 3 shows the position of the anchor or escapement lever immediately before
its fall.
Fi 4 is a longitudinal section. of a clock provided with the improved

page_text: escapement and with a pneumatic winder to maintain the weight at a constan
height, and
Fig. 5 is a front view of the improved clock.
present
As will be seen by the drawings, the escapement lever B (anchor in the
example) is not arranged above the escapement wheel R, but at its side where it
oscillates freely on its centre of motion. From its centre extends horizontally a
screw threaded lever L upon which is screwed a tapped counterpoise C, which
determines the fall of the upper pallet bas soon as it is left to itself, that is to
say, disengaged from the pendulum P. At the centre of the escapement lever
(anchor) B is fixed, in addition to the counterpoise lever L, an arm B which
extends downwards, either vertically or in a position more or less inclined from the
vertical, but always so that an action exerted, by reason of the direction of the
arm, in contrary direction to that of the counterpoise C, shall always be overcome
by the latter and cannot prevent the fall of the upper pallet as soon as the
escapement lever (anchor) is liberated.
The downwardly extending arm B' takes the place of the old fork to effect
connection between the escapement lever (anchor) and the pendulum, but not in
the old invariable and permanent manner, but in an adjustable and temporary
manner, so that at a given moment the escapement lever (anchor) shall find itself
solely under the influence of the counterpoise and that the pendulum shall complete
its motion in full liberty. For this purpose the lower extremity of the said arm B
should be connected to the pendulum by means of a membrane effecting at the
required times the said connection and disengagement of the two parts, and the
membrane enabling these two functions to be realized in the most simple manner is
a flexible connection M, preferably a cord, capable of being lengthened or shortened
at will to obtain the exact adjustment between the escapement lever (anchor) and
the pendulum, by a stud or terminal K turning with sufficient friction in the lower
end of the arm B3 and upon which the cord is wound.
The adjustment being arranged between the escapement lever (anchor) and the
pendulum, the regulation of the entire system is effected by shifting the counter-
poise Cupon the lever L, and it will be readily understood that by this agency
there is obtained a much more precise regulation than by the simple displacement
of the bob of the pendulum.
In effect, the speed of the escapement lever (anchor) will no longer depend
solely on the length of the pendulum, so that no matter what position of the bob,
the speed can always be regulated by means of the counterpoise C in such manner
that each motion corresponds always exactly with the passage of one tooth of the
wheel in the desired time and at the fraction of motion during which the pendulum
vibrates freely and the wheel is stopped.
The working of this escapement can be readily understood from the preceding
description.
The pendulum having accomplished its full motion towards the right (see Fig. 2),
the lower pallet 6' of the escapement lever (anchor) stops the wheel in the ordinary
manner; then, in commencing its beat towards the left, the tooth pressing against
the pallet b', gives impulse to the system in the known manner to drive it towards
the left, in which motion it is again assisted by the counterpoise C of the escape-
ment lever as the flexible membrane or cord M is distended, that is to say, that the
pendulum and the escapement lever (anchor) are connected together.
This state of rigidity is maintained to about half of the beat of the pendulum,
which is then in its vertical position. About this moment the upper pallet 6 of the
escapement lever (anchor) commences to touch the inclined face of the
corresponding tooth, and from this moment it no longer follows the pendulum,
which continues its beat, slackening the flexible membrane M, whilst the counter-
poise C effects the fall of the upper pallet b, which then invariably stops the wheel
during the period in which the pendulum completes its beat towards the left and
returns to again distend the membrane, raise the upper pallet b, and re-commence
the same motions.

page_text: It will be remarked that by this agency the wheel is stopped at each second
tooth, or for one entire vibration of the pendulum, during a constant and invariable
period, so that it is of little consequence whether the stoppage of the intermediate
tooth is more or less constant or is subject to the eventual irregularities of the
pendulum, the independent stoppage of the second tooth always. correcting them in
an inevitable manner upon the entire vibration so that the speed of oscillation is
suitably regulated with relation to the rotation of the wheel; the working of the
clock will be of an absolute precision.
This precision can further be increased if there is combined with the arrangement
above described an automatic winding apparatus represented at Fig. 4 and
consisting of a pneumatic fan or turbine working so as to maintain the weight at
about the same height, or the spring at constant tension if this latter motive power
is used instead of a weight. The drum of this turbine can be connected with a
draft flue, or otherwise be exposed to the action of a constant current of air which
operates it.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
CLAIMS.
1. In a pendulum clock, an escapement comprising the combination of the
escapement lever (anchor) and the pendulum in such manner that, during a given
phase of the vibration, these two parts shall be invariably connected and work
together, whilst they work in complete independence from each other during the
other phase, with a view to stop the wheel at each second tooth during a determined
and invariable period, substantially as herein shown and described.
2. The method of construction of the escapement herein described, comprising
the operation of the escapement lever (anchor) by an adjustably counterpoised
lever. L and an arm B whose lower extremity is in connection with the
pendulum P by a flexible membrane M, substantially as herein shown and
described.
3. The improvements in escapements for pendulum clocks substantially as
herein shown and described and for the purpose stated.
71
T
'1 100r
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.