Improvements in Apparatus for Measuring Time by Electricity.
Year: 1899

page_text: Date of Application, 10th July, 1899-Accepted, 2nd June, 1900
COMPLETE SPECIFICATION.
Improvements in Apparatus for Measuring Time by Electricity.
I, MAX HOEFT, of 12, Trebbinerstrasse, Berlin,, in the Empire of Germany,
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:-
This invention relates to a device for measuring periods of time by means of
electricity, that is to say the object of the invention is a certain kind of electric
clock or watch. The main arrangement is distinguished by an automatic circuit
breaker, consisting of an electro magnet between the pole pieces of which an
oscillating armature is suspended which being attracted upon the excitement
of the electro magnet breaks the electric current, whereupon the armature being
returned to its normal position by the action of an adjustable spring, the current
is re-established, this action being continuously repeated. The movement of
the armature of the automatic circuit breaker is the actuating medium for the
revolution of the gear of the clock or watch.
In the accompanying drawing illustrating the present invention in two con-
structional modifications:
Fig. 1 is a back view of the electric clock.
Fig. 2 being a side elevation thereof.
Fig. 3 a horizontal section on line A-B of Fig. 1.
Fig. 4 is a back view of a modification adapted for pendulum clocks.
Fig. 5 a side view of the same.
Figs. 6 and 7 show details of construction.
The automatic circuit breaker consists of an electro-magnet 1 bearing pole
pieces 2. Between these pole pieces an armature 3 is arranged rotatable around
a shaft 4 journalled in the metal support (Figs. 2 and 3) in such a manner as.
to permit the rotation of the armature 3 independently of the motion of the
shaft 4 so that it is possible to rotate the armature 3 while the shaft is at rest
Motion is imparted to the armature 3 by means of an antagonistic spiral spring 5
allowing of a most delicate adjustment by the use of a suitable check nut.
Upon an electric impulse passing through the coils of the electro magnet -1
the armature 3 is turned so as to bring its longitudinal axis exactly or nearly
to coincide with the connecting line of the pole pieces.
The device for establishing the circuit consists of the closing pin 9 (Fig. 5)
which by means of a projection is attached to a disc 8 rotatably connected by a
small sleeve to the armature 3. or the shaft 4. The disc is however only allowed
a very small rotation relatively, a narrow notch 11 being provided in the disc 8
with which a pin 10 fastened to. the armature 3 is made to engage.
The current passes to the disc 8 and thence to the closing pin 9 by the medium
of a weak sliding spring attached to the metal support. Another flat spring 12
Price 8d.]

page_text: being likewise fastened to the support and having a pawl 13 attached to it, is
made to engage the rim of the disc!8 which is provided with two indentations 14.
A movable arm 16 rotatable about the pivot 15 is attached to a base plato
suitably insulated from the frame of the watch or clock, said arm 16 being
pressed in contact with the closing pin 9 by a light flat spring 17 and being
screwed into an angle piece 18 provided with a platinum contact. Besides
there is fixed to the underside of said rotatable arm aud insulated therefrom a
small ratchet pawl 19 spring actuated and engaging with the teeth of the ratchet
wheel 7 (Fig. 6) freely rotating upon the shaft 4. A small flat spring 6 acting
as an operating spring and fastened to the side of the armature 3 also engages
said ratcliet wheel 7.
The herein described. device for the establishment of the current acts inter-
mittently as appears from the drawing and description, the armature 3 being
attracted upon the electro-magnet 1' being excited which results in an imme-
diate movement of the spring 6 across the ratchet wheel which is arrested by
the pawl or detent lever 19 of the rotatable arm 16 while the indentations 14
of the disc 8 following the rotation of the armature 3 move past the pawl end
of the flat spring 12. Since the ratchet wheel 7-as has been stated-is inde-.
pendent of the rotation of the armature, the shaft 4 rigidly connected to said
ratchet wheel will remain stationary during the movement of the armature:
As soon as the armature 3 has finished its motion, the spring 6 again engages
the teeth of the ratchet wheel 7 as also is the case with the ratchet pawl 19
attached to the rotatable arm 16. At the same time however the closing pin 9
is moved out of contact with the platinum contact of the angular picce 18 by
the rotation of the disc 8 thus breaking the circuit. The armature 3' is now
free to follow the action of the helical spring 5 by which the said armature is
withdrawn, the said spring 5 frictionally moving the ratchet wheel 7 and the
shaft 4 turning the latter for a certain definite angle.
The disc 8 having positive connection with armature 3 by means of the pin 10
as before stated, is compelled to follow this rotation; thus the pin 9 of the said
disc 8 is at last brought in contact with the platinum contact of the angular
piece 18 while the pawl end 13 of the spring 12 intermittently jumps over the
indentations 14 of the said disc 8. Contact is established at the moment of
engagement of the pawl 19 with the corresponding indentation of the ratchet
wheel 7 the rotation of the latter raising the said pawl 19. Thus the circuit is
again established transmitting another impulse of the current and repeating the
process just described over and over again. Fastened to the end of the shaft 4
eituated within the registering device is a pinion 20 which imparts motion to
the gear 21. Since the shaft 4 is only rocked upon the return movement of the
armature 3 the registration device is consequently actuated upon the return of
the armature only, the motion solely originating from the uniform action of
the spring 5. Any possible small variations in the strength of the current used
for exciting the electro-magnet are therefore without influence upon the accuracy
of the movement of the clock work.
In order to as much as possible retard the return movement of the armature 3
and to correspondingly diminish the number of times the current is closed by
the pin 9 in a given period of time and in order to thus economise the electric
energy upon which the operation of the apparatus depends there is provided an
escapement of a well known form: Any escapement may be used with advantage
for instance a cylinder escapement may be employed such as is represented in
Fig. 1-3 in which the pinion 20 engages the toothed wheels 21, 22 and 23 of
the escapement. This form of escapement is of the usual well known kind, the
escapement wheel engaging the cylinder 24 which is connected in the usual
manner with the balance 25 and the spiral spring 26.
The modification shown in Figs. 4 and 5 is distinguished by a pendulum
escapement instead of a cylinder escapement; the cylinder 24 being replaced by
the lever 27 and the balance 25 by the pendulum 28.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. An electrical clock or watch characterized by an armature 3 of soft iron
actuated by the influence of a spiral spring 5 which armature is rotated upon
excitement of the electromagnet 1 in which case the armature winds the spring 5
but does not turn the gear of the clock, whereas the latter is set into motion
controlled by a cylinder or pendulum escapement when the armature 3 returns
to its normal position.
2. An electrical clock or watch as described in Claim 1 distinguished by the
fact that the actuating spring 5 is capable of very delicate adjustment, whereby
great accuracy in the movement of the clock is attained.
3. An electrical clock or watch as described in Claim 1 characterized by an
adjustable spring 5 in combination with any suitable common escapement for
the purpose of obtaining the greatest possible accuracy in indicating the time.
4. A device establishing the circuit for electrical clocks or watches, charac-
terized by a contact lever 16 pivoted at 15 which closes the circuit by means of
a pawl or detent lever 19 engaging the ratchet wheel.7 on shaft 4.
5. In electrical clocks or watches a device for actuating the ratchet wheel, 7
driving the gear of the clock work, consisting of a spring pawl 6 fastened to
the armature 3 and engaging the teeth of the ratchet wheel 7.
6. A device for breaking the circuit in electrical clocks or watches: distin-
guished by the combination of the armature 3 with a disk 8 freely rotatable on
shaft 4 by means of a pin 10 on the armature 3 engaging a slot 11 of the disc 8
and indentations 14 in the said disk 8 in which the spring 12 with pawl 13
enters for the purpose of regulating the exact position of the disc 8 and the
contact piece 9 integral therewith.
Dated this 10th day of July 1800
HERBERT HADDAN & Co.,
Agents to Applicant, 18, Buckingham Street, Strand, W.C.