Improvements in Electrical Clocks.
Year: 1897

page_text: Date of Application, 26th Mar., 1897
Complete Specification Left, 26th Jan., 1898-Accepted, 26th Mar., 1898
PROVISIONAL SPECIFICATION.
Improvements in Electrical Clocks.
We, FRANK HOPE-JONES and GEORGE BENNETT BOWELL, of 53, Victoria Street,
London, S.W., Electricians, do hereby declare the nature of this invention to
be as follows:-
This invention has for its object improvements in electric controlling clocks
and electrical indicating dials worked therefrom. These improvements include
novel arrangements of the electrical circuits.
It consists in part of improvements and developments of the system described
in our Patent Number 1587, 1895.
When it is desired that the self-wound controlling clock should send out
impulses every second, the pendulum is usually operated by one or more gravity
arms which are lifted by electro-magnets at each vibration, such as for instance
that described in Figure 1 of the Patent above referred to.
But for this purpose
it has always been necessary to employ some form of closed circuit battery
owing to the excessive duration of the contact. Now in this invention quick
contacts may be obtained by the use of contact pieces between the gravity arms
and the armature of the electro-magnets, the said contact pieces resting in slides
with freedom to move lengthways and so arranged that when one gravity arm
touches its contact piece the circuit of its electro-magnet will be closed and the
amature will impart a percussive blow to the said sliding contact piece which
will cause the gravity arm to engage in a catch and will instantly break the
circuit, or the armature itself may be used to make contact with the gravity
arm without the intervention of a sliding contact piece, in which case a fixed
stop is provided to limit the armature stroke and as no such stop is provided for
the gravity arm, the momentum of the latter will carry it on, causing a quick
break.
When a contact at longer intervals is required, such as say at every 15 or
30 seconds, the pendulum is operated by an ordinary escapement, as for instance
in the manner described in Figures 2 and 3 of our Patent referred to, where
the clock is driven by a weight which meets the armature of an electro magnet,
makes contact therewith and is reset, thus sending out a make and break signal
every 15 or 30 seconds to operate any number of dials in electrical circuit there-
with.
In this patent in order that the action of the controlling pendulum and one
of the dials may be electrically interlocked we omit the fixed stop in the path
of the armature of the pendulum movement and provide a contact on some
moving part of a dial and arrange the wiring so that the circuit is broken there
(instead of at the pendulum) immediately the operation of driving the dial one
step forward has been performed. If it is desired that more than one dial be
electrically locked with the controlling apparatus for closing the circuit in this
manner, the breaking contacts on the dials as described above may be arranged
in parallel:

page_text: For the purpose of operating the hands of any number of indicators or dials
in circuit with controlling blocks we employ a new method of step by step
movement which is more simple than those commonly used and calculated to
secure greater economy and reliability. This form of dial movement consists
of an electro-magnet operating a vibrating armature lever. Pivoted at one end
of the said lever is a pawl which engages in a toothed wheel attached or geared
to the hands of the dial. Each tooth of this wheel forms a right angled
isosceles triangle hypotenuse of which forms a tangent to the wheel. The
free end of the pawl is also rectangular and normally rests upon a tooth in line
with its face i.e. at an angle of 45° with the radius at this point, and when
driven forward either by an electro-magnet or by a spring acting in opposition
thereto, it drives the wheel and rises with it until it meets with a fixed stop
which effectually prevents it or the wheel from proceeding further, while a
back stop click prevents the wheel from returning. By arranging the parts in
this manner it will be seen that the forward motion of the driving click in the
direction of its length is equal to the rise of its free end and that while the said
click normally locks the wheel it is nevertheless free to slide straight off the
dead surface of the tooth without being lifted when the next impulse is sent
out from the controlling clock. The angle at which the click engages the wheel
is important. If the click enters the wheel at a tangent, the slightest eccentricity
in the wheel will cause the click to bind between the circumference and the fixed
stop at some points or will allow excessive free play between the backward and
forward locking as above described.
>
It is also important that the direction of the outward movement of the driving
click should be parallel with the face of the tooth upon which it rests.
It is sometimes desirable to attach to the backstop click the armature of a
smaller magnet placed in series with the magnet for operating the dial move-
ment in order that the driving wheel may be locked while the current is drawing
out the click.
1
We, FRANK HOPE-JONES and GEORGE BENNETT BOWELL, of 53, Victoria Street,
London, S.W., Electricians, 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: —
Our invention relates to electrical clocks and similar instruments.
One object of our invention is to construct an improved electrically wound
regulator or controlling clock in which the continuity of the electric circuit is
maintained for a short period of time only; by this means we are enabled to use
an open circuit battery such as a Leclanche battery in place of a closed
circuit battery. Another object of our invention is to so arrange the electric
circuit in a system of electrically controlled clocks that the same shall be first
interrupted in the movement of one of the controlled clocks, and not be made
again until said clock has been operated. Consequently the next time that
the regulator requires rewinding if said clock has not been operated a circuit

page_text: can no longer be established, and the whole system is stopped until the clock
movement is put right.
In order that our invention may be clearly understood. we will now proceed
to describe the same with reference to the accompanying drawings how we may
carry out the same in practice.
Figure I is an elevation illustrating our improved regulator.
Figure 2 illustrates diagrammatically a system wherein a regulator is con-
trolling a single electrical clock, the circuit being arranged in accordance with
our present invention.
Referring now to Figure 1 the regulator therein shewn is of the type illustrated
in Figure of the drawings accompanying the Specification of Letters Patent
No. 1587 of 1895 granted to us. H is the pendulum supported by a suspension
spring in the usual manner. CC are impulse arms or gravity, pieces
centred at C3 C and provided with contact arms C5 C6. A' A are detents
pivoted at AA and adapted to engage with pallets C C provided on the impulse
arms CCThe pendulum H is, furnished with a roller H2 centred at H³ and
so arranged that as the pendulum vibrates said roller alternately depresses
the detents A A², thereby releasing the pallets C7 C³. The electrical portion of
the regulator comprises two electro-magnets 1 D¹ having armatures De D³ pivoted
at D D respectively. The pivots are arranged to insulate the armatures from the
base. Said armatures are provided with contact points adapted to make contact
with the contact pieces C5 C of the impulse arms.
The movement of the arma-
tures D2 D3 is limited by insulating stops D as shewn. X is an electrically operated
dial movement of any suitable, description and C is the battery. The electrical
connections are as follows. From the battery C through wire 1 to the dial move-
ment. From the dial movement through wire 2, electromagnet D, armature D²,
contact piece C, pivot C3, to the base; and from the base by wire 3 to the battery C
again. The electromagnet D' is connected by the wire 4 to the dial movement and
through armature 1³, and contact piece C to the base. It will be readily under-
stood from the foregoing description that when armature D2 is in contact with
contact piece C, current will flow through electromagnet D) and through the dial
movement, the electromagnet 11 being in circuit when its armature D³ is in
contact with the contact piece Cº.
The operation of the regulator is as follows:-
In the drawing the pendulum is shewn at rest the circuit being open. On
starting the pendulum by swinging it say to the left, the roller H2 presses down
the detent H, thereby releasing the pallet C7, the impulse arm C then drops
and the pin C on the end thereof and comes in contact with the pendulum. As
the pendulum continues to swing to the left the impulse arm C₁ is lifted rotating
on its pivot C3 and the detent A¹ is depressed still further owing to the roller H2
travelling up the incline A5. When the pendulum has reached the limit of its
movement and begins swinging to the right the impulse arm C₁ follows it and
since the detent A is held down by the roller H2 the pallet C7 will be enabled to pass
the detent. The movement of the impulse arm C¹ and pendulum H continues
until contact piece C³ makes connection with armature 12 upon which the circuit
is made through electromagnet 1). The armature 12 is thereby attracted and pulled
upwards raising the impulse arm C. The upward movement of the armature D³
is limited by the upper stop D6, while the movement of the impulse arm C
upon its pivot C3 is not limited; consequently the circuit will be broken between
the contact piece C³ and the pin at the end of the armature D. When this
occurs the magnet. D. being no longer energized permits the armature D2 to
fall to its lower stop and the impulse arm C¹ will also drop. Meanwhile, however,
as the pendulum H continues to swing to the right the roller H2 will have
left the incline A³ and the detent- A will have moved up, and consequently is
in position to engage the pallet C when the arm C¹ drops. As soon the
pendulum H has passed its middle position when, swinging to the right the
cycle of operations above described with reference to the left hand impulse arm

page_text: and detent A¹ and will be repeated with the right hand impulse arm C and
detent A, consequently the electromagnets D and D¹ will be put in circuit with
the battery C and dial movement, alternately during each single vibration of the
pendulum H.
In order to ensure the detents A¹ A³ engaging with their respective pallets they
are lightly weighted as shewn at A6, stops A7 being provided to prevent the detents
rising too high.
It will be observed that at the time when the contact piece C³ makes connection
with the armature D2 the pallet C7 is in contact with the incline A5, so that a
small amount of friction at this surface will require to be overcome when the
impulse arm is raised by the electromagnet.
In order to obviate this we
sometimes provide additional electromagnets E E¹, shewn in dotted lines in the
figure, connected in series with the magnets D D¹ respectively, and adapted when
energized to pull down the respective detents A' A². By these means as soon as the
magnet D for example is energized and begins to raise its armature D² the
magnet E will also be energized and depress the detent A¹ which will therefore
offer no impediment to the rise of the impulse arm C¹. A further advantage
which arises from this arrangement is that the incline A needs not to be extended
as far as the notch of the detent, consequently during the time when the impulse
arm is giving energy to the pendulum, namely, when it is falling from the position
shewn in the drawing to the position where its contact piece makes connection
with the armature of the electromagnet the pallet C will not be in contact with
the detent. The mechanism shewn in the drawings is of course bilaterally
symmetrical, and the description of the parts and operation of the detent A¹ and
impulse arms C¹ is applicable to that of the detent A³ and impulse arm C³.
It will be observed that the current from the battery C is flowing only during
the movement of the armature D² from its lower stop to its upper stop, consequently
it follows that the battery C is nearly always on open circuit.
Referring now to Figure 2A is the regulator controlling a clock movement B,
the battery or other source of electricity being indicated at C as before.
a is a ratchet wheel, the rotation of which is governed by any suitable escape-
ment, such as an ordinary pendulum escapement for example. is a lever pivoted
at and provided with a click 63 which engages with the teeth of the wheel a.
Said lever is operated by a spring 63, and through the click tends to rotate the
wheel in the direction of the arrow. Instead of the spring a weight
may obviously be used to act upon the lever b. c is a lever pivoted at cl
carrying the armature ² of an electromagnet e. Said lever also carries a contact c³
adapted to connect with the lever b. The downward movement of lever c_is
limited by the stope and a stop d is provided for limiting the movement of the
lever in an upward direction.
Referring now to the movement shewn at B3 which is controlled by the regulator A,
f is a wheel which may be in connection with the minute hand of a clock or which
is otherwise. adapted to drive the remaining wheels of a clock dial. Said wheel
is provided with rectangular teeth the faces of each teeth making angles of 45° with
the radius of the wheel. f is a lever pivoted at carrying the armature fof
an electromagnet c¹. Said lever is also provided with a click f which engages with
the teeth of the wheel 7. f is a spring which operates to move the lever f
forward and so rotate the wheel f in the direction of the arrow. The movement
of the said lever is limited on one direction by the stop f, in the other direction
by the stop f against which the click f is pressed if the wheel f is rotated a
certain distance. f is a spring mounted on the click f which in the normal
position of the lever f¹ and click makes contact with an insulated stud f. To
prevent the wheel f running back we provide a retaining click. f10 pivoted at f
and adapted to engage with the teeth of the wheel as shown. The electric. circuit
is as follows From the battery C through the wire g to insulated terminal t on
the base of the controller B. From terminal through the electromagnet el
spring f³ click f* and spring f to stud and thence to terminal to through

page_text: wire g to insulated terminal 3 on the base of the regulator A. From
terminal through electromagnet e lever band when lever b and contact c³
are in connection, through lever c, insulated terminal and from said terminal
through wire g² to the battery C. It must be observed that the stud e¹ and
the pivot ¹ are insulated from the base of the regulator in order that the circuit
may be broken when the lever b is raised out of contact with the point c³.
The operation of the system is as follows-The lever 6 moves on its pivot under
the influence of the spring and through the click 62 rotates the wheel a in the
direction of the arrow, the speed of rotation of said wheel being regulated by the
escapement. As soon as the lever b reaches the contact the circuit is made and
a current from the battery C passing round the electromagnet é energises the same
and armature c² is attracted, thereby raising lever b to its topmost position, so that
when the armature is released the lever b will be again in a position to operate
the wheel a. It will be observed that during the rise of these two levers the contact
point rubs on the lever b and by this means is maintained clean and in condition
to afford a good electrical contact. The making of the electric circuit also energises
the magnet e in the clock movement B whereupon the armature 3 is attracted
and lever f moves in the direction of the arrow against the force of the spring f
withdrawing the click ft from the teeth of the wheel f. As soon as this withdrawal
is accomplished the click f drops so as to engage with the next tooth of the
wheelf and in so dropping breaks the connection between spring fs and contact
stud f. The armature in the regulator A and also the armature f³ in the
movement B are thereby released, and the levers and f¹ return to their normal
position. In doing so the lever c makes an additional break in the circuit, namely,
between the lever b and contact . The lever f¹ which moves forward under the
influence of the spring f³ as soon as its armature is released rotates the wheel f
in the direction of the arrow through the click f until said click is brought into
contact with the stop fe at which time the spring f again makes contact with the
stud f. No current will, however, flow round the circuit until the lever bis
dropped sufficiently to again make contact with the point c. During the rotation
of the wheel the retaining click f10 is raised, and falls into the next tooth of the
wheel.
It will be observed from the foregoing that the wheel f is rotated through the
space of one tooth every time the lever makes contact with the point The
establishment of the circuit and consequent re-setting of the lever b is, however,
dependent upon the operation of the wheel f since the spring f8 will not connect
with the stud f unless the click f has moved forward.
One or more clock movements similar to that illustrated at B may be employed
with the same regulator, the current passing through them on the same circuit
and in such a case it is generally only necessary to provide for breaking the circuit
in one of said movements.
An important advantage which we obtain with our improved system is that the
circuit is maintained while the work is being performed but is cut off the moment
the work is done, hence the duration of contact is always sufficient to ensure the
proper operation of the clock movement, and at the same time is not unnecessarily
prolonged.
The form of the teeth of the wheel f, namely, with straight faces making an
angle of 45° with the radius taken into conjunction with the position of the
click f which is also normally at 45° to the radius, is important inasmuch as
the click moves straight out of engagement with the wheel teeth, and consequently
will be operated very readily, so that a very short duration of contact between the
lever and point will cause the operation of the clock movement B. In a move-
ment of this description as ordinarily constructed the click f* is approximately
tangential to the wheel f and the stop f being located immediately above the said
click the smallest eccentricity in the wheelf would cause the click to bind between
the wheel and the stop, and thereby interfere with the operation, this does not
occur with our improved device.

page_text: It is sometimes desirable to attach to the retaining click f10 the armature of a
small magnet connected in series with the magnet el, by this means we ensure
that the driving wheel f shall be locked while the driving click f is being
withdrawn.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what we
claim is:-
1. A gravity escapement provided with means operated by the pendulum for
mechanically releasing the impulse arms from their respective detents, and with
electromagnetic means for raising and replacing said arms when necessary, either
with or without electromagnetic means for holding the detents clear of the impulse
arms at the movement of replacement.
2. A gravity escapement constructed and operating substantially as described
with reference to Figure 1 of the accompanying drawings.
3. A system of one or more dial movements, electrically operated and controlled
by an electrically wound regulator and so arranged that the electric circuit is
interrupted at a dial movement before being disconnected at the regulator and
cannot be again established until the said dial movement has been operated and
the regulator requires resetting.
5. In an electrical indicator dial movement of the class described, the click f
and its adjacent co-operating parts constructed and operating as described.
6. A dial movement constructed and operating as described with reference to
Figure 2 of the accompanying drawings.
T
1000
1000
UL Danua y 1530
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham,
Patent Agents for the Applicant.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham,
Patent Agents for the Applicant.