Improvements in Electric Clocks with Synchronising Mechanism.
Year: 1889

page_text: Date of Application, 23rd Mar., 1889-Accepted, 13th July, 1889
COMPLETE SPECIFICATION.
Improvements in Electric Clocks with Synchronising Mechanism.
A communication from RENÉ POUCHARD, of Paris, in the Republic of France.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex, M.L.M. E.,
hereby declare the nature of this invention and in what manner the same is
be performed, to be particularly described and ascertained in and by the following
atement:-
The present invention relates to electric clocks by means of which all clocks included
the same electric circuit can be synchronisod.
Fig. 4 represents a commutator for reversing the current.
These three apparatus are electrically connected by means of the wires ab of
which a is connected with the positive pole of a suitable battery Q and b with the
negative pole.
The regulator Figure 3 consists of an ordinary clock-movement operated either by
weights or by a spring and regulated either by a pendulum or a balance. Every
minute or part of a minute this regulator makes contact and thus closes the circuit
from the battery Q (Fig. 4) the current from which then passes through the electro
magnet A (figures 1 and 2).
If the regulator is to make one contact per minute, the wheel R (figures 1 and 2)
of the receiver will have 60 teeth and if the regulator is to make one contact everý
half minute the wheel R will have 120 teeth, which corresponds exactly with one
rovolution per hour.
The contact can be of any suitable form but it is preferably a friction contact, because
the point of breaking the contact is not at the point of making the contact and the
spark consequent on the breaking does not take place at the point of making which is
thus not worn so much as it would be otherwise.
The current from the regulator passes to the electro-magnet A (figures 1 and 2)
which is provided with two pole pieces E and D. The magnetising of these pole
pieces attracts the soft iron armature B which is pivotted at C.
The other end of the armature B is pivotted to a link K which connects the
armature with the lever H G pivotted at o, the arm G of which is provided with au
adjustable counter weight y by means of which the amplitude of the oscillation of the
lever E, G, consequent on the attraction of the armature B can be regulated. From
the point or screw L in the arm G is suspended a pawl F the lower end of which
engages with a ratchet wheel R having 60n teeth and this pawl is attached to the
arm G in such a manner that it is always in engagement with the teeth of the ratchet
wheel without the aid of a spring. The descent of the paw! F is limited by a stop M
and its ascent by the downwardly projecting arm N of the lever HG when it comes
into contact with a lever 1 pivotted at e. At its free end this lever I is provided with
a detent P preferably made of steel. This connection of the pawl F with the arm N
and lever I entirely prevents the ratchet wheel R from moving backwards and admits
of it moving forward only to the extent of one tooth during the attraction of the
armature B.
The ratchet wheel R in this manner is moved every minute one sixtieth of a
revolution, and on its spindle is fixed the minute hand of the clock. The movement is
transmitted to the hour hand in the usual manner.
The sixtieth tooth z of the ratchet wheel R is cut deeper than the others and forms
thus a notch or recess into which the detent P of the lever I can fall.

page_text: counterweight V.
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The arms QT of this. magnet can come into contact with a stud X projecting
laterally from the pole piece E of the electro-magnet A. This stud is provided with a
sleeve m preferably of copper. The pole piece E and stud X forms either a north or
south pole of the magnet according to the direction of the current passing through
the electro-magnet A. Consequently if it is a north pole it will attract the south pole
of the magnet QST and if it is a south pole it will attract the north pole of the
magnet QST. The lower arm T of the latter carries a projecting piece U the top of which
is flush with the lowest point of the recesses between the teeth of the ratchet wheel R when
the arm T is in contact with the stud X and thus limits the fall of the pawl P. When
the arm is in contact with the stud X the pawl P will not rest on the projecting
piece U of the arm T and will consequently fall into the notch Z when this comes
underneath it and arrest the progress of the ratchet wheel R until it is lifted again by
the projecting piece U of the arm T. In the normal state the current passes through
the electro-magnet A in such direction that the arm T is in contact with the stud X
so that under such normal condition the detent P does not arrest the movement
of the wheel R.
If the clocks to be synchronised are fast the current is reversed by placing the
arms hk so as to make contact with lh. The arm Q will then be attracted to the
stud X and the detent P will then fall into the notch at the 60th tooth and arrest
the movement of the ratchet wheel R. The current is reversed about 25 or 30
minutes before the hour and within the first minute of the next hour the pawl P is
lifted by returning the commutator to its original position to attract the arm T towards
the stud X and lift the detent P.
When the clocks are slow and are to be synchronised at the exact hour a series of
contacts are made by the button n figure 3 to advance the ratchet wheel by as many
teeth as contacts are made and if at this moment the arm is in contact with the
stud X tho pawl P will fall into the notch and arrest the movement of the ratchet
wheel R thus all the clocks in the circuit will be stopped at exactly the same point and
then the commutator is reversed to start all the clocks at the exact hour.
To prevent a too sudden movement of the hands a toothed wheel preferably having
fine teeth is fixed on the spindle of the wheel R and this wheel gears with a pinion g
on the spindle of which is fixed another toothed wheel t which gear with a pinion a
which latter carries a vane v. This gearing is so proportioned that the vane makes for
instance ten revolutions while the wheel R moves for the space of one tooth, this
considerably slackens the movement of the hour hand. This gearing may be replaced
by a worm and worm wheel the spindle of the worm carrying the vane. "
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent, I declare that what I claim is ;-
1. In an electric clock an electro magnet A having two pole pieces DE a pivotted
armature B connected to a link K and lever HG N which carries a pawl F constantly
engaged with the teeth of a ratchet wheel having 60 teeth and carrying on its shaft
or arbor the minute hand substantially as described and represented in figures 1 and 2.
2. In an electric clock such as described the synchronising mechanism consisting
essentially of the pivotted magnet QST either of the arms of which can be attracted
by the stud X of the pole piece E of the electro-magnet A according to the direction
of the current passing through the circuit, the arm T being provided with a projecting
piece U which supports the detent P.or lets it fall into the notch forined in the ratchet
wheel R so as to arrest the movement of the latter exactly at the hour substantially as
described and illustrated in the accompanying drawings.
3. The combination with synchronising mechanism such as described of a contact
button n and a reversing switch board or commutator (figure 4) enabling a series of
currents to be passed in one direction through the electro-magnet A in case the clocks
are slow and in the reverse direction to let the arm T drop so as to stop the wheel R

page_text: by the detent P engaging with the notch substantially as described and illustrated in
the accompanying drawings.
4. The arrangement of toothed gearing rqt a connected with the ratchet wheel R
and of the vane v carried by the pinion for the purpose of slackening the movement
of the hands substantially as described and illustrated in the accompanying drawings.
Dated this 22ed day of March 1880