Improvements in Alarm Clocks.
Year: 1899

page_text: Date of Application, 4th Dec., 1899 -Accepted, 6th wall, rovd
COMPLETE SPECIFICATION.
Improvements in Alarm Clocks.
I, LUDWIG SCHIFF, of 1-3, Bingerstrasse, Wilmersdorf, near Berlin, in the
Empire of Germany, Engineer, do hereby declare the nature of my said invention
nd in what manner the same is to be performed, to be particularly described
nd ascertained in and by the following statement ;-
In alarm clocks of ordinary construction, the release of the spring mechanism
operating the alarm, is effected by an eccentric fast on one of the time indi-
cating spindles and its hand (thus for instance the hour or minute hand) the
moment the hand in question (or the eccentric) which is driven by the clock-
The position occupied by the various
work has attained a certain position.
parts of the mechanism in order to effect the alarm is either permanent
(i.e. it may correspond with the position to which the hand is adjusted), or it
is of itself adjustable, in which case it is generally indicated by means of a
The eccentric may be variously shaped, it may consist
separate alarm hand.
of a disc having a peripheral notch or a cylinder having a facial depression
or a disc provided with a pin or the like. The release of the alarm device is
generally effected directly, by the movement of the detent lever into the
notch or depression, or it may take place owing to a movement of the
release disc or eccentric at the expiration of the predetermined period.
The notch, which either directly or indirectly allows of the movement of the
detent lever, has a sharp fall at one side and a gradual incline at the other,
in order to effect, the release of the detent lever, suddenly whilst the further
movement of the release eccentric will arrest the alarm device by moving back
the detent lever. It is however in many cases, advisable to avoid arresting
the alarm mechanism by the continued rotation of the shaft to which the
5 release eccentric is keyed.
This is effected, according to the present invention by connecting the release
eccentric to the shaft, driven by the clockwork, by means of a coupling, which
is automatically uncoupled as soon as the alarm mechanism has been released,
thus, enabling the release eccentric to remain in its freed or released position
30 during the further rotation of the spindle driven by the clockwork, whilst the
arrest of the alarm mechanism can only be effected by the further movement of
the release eccentric by hand.
In order to render the present specification easily intelligible reference is
had to the accompanying drawing in which similar letters of reference denote
35 similar parts throughout the several views;-
40
-
Fig. 1 is a front elevation of the parts of an alarm device necessary for
properly illustrating the object of the present invention and Fig. 2 a sectiona
side elevation of Figure 1. Fig. 3 is a front elevation of a modified form o
the device and Figure 4 a sectional side or end elevation of Figure 3.
For the purpose of the present specification it has been assumed that th
release of the alarm lever is effected by a cam notch in the release disc i.e. b
of a cam disc a is the detent lever for the alarm mechanism, which

page_text: held against the releasing disc or came by means of a spring b. The alarm
mechanism is not illustrated, not forming part of the present invention. The
detent lever will release the alarm mechanism as soon as the notch of the cam
comes into contact with its free end. This position of the cam will be attained
as soon as the hand d reaches the point indicated by O of the dial e. The cam
or eccentric is loosely mounted on the spindle and the said spindle f is
mounted in the axial boring of the wheel so as to move with the said wheel g,
when the latter is driven by the clockwork. The parts hitherto described are
exactly the same in both modifications. In the device shown in Figures 1
and a ratchet gear is mounted at the rear of the eccentric or cam c on
the spindle f, said gear being, however, fast on the said spindle. On the rear
face of the came a pawl is mounted, which is retained against the teeth of
the ratchet wheel by means of a spring, thus coupling the came with the
wheel e. the spindle f. Shortly after the parts have attained the release
position, the ratchet will strike a pin m and be turned on its pivot, thus
releasing the wheel h. Thus the cam will remain stationary and the alarm
will continue to operate. If however the hand or the eccentric is turned by hand
in the direction of the arrow (Fig. 1),. the pawl i will be forced past the pin m
and will then be free to engage the ratchet wheel again thus coupling the
cam and spindle. The detent lever a will also be moved into operative position
by the cam surface of the notch or the cam. When the came is moved by
hand, as soon as it and the spindle have been coupled, the latter will have
to overcome the friction in the boring of the wheel I, the parts being so
adjusted that this friction shall be sufficient to move the spindle with the
wheel when the latter is driven by the clockwork as herein before set forth.
According to the device illustrated in Figures 3 and 4, the rear face of the
cam e carries a brake band o, which is tightened on to the brake disc
on the spindle f, by turning the lever which is pivotally mounted on the
said cam face. The lever is a sort of tumbler, one finger of which is operated
by the spring to operate or tighten the brake band and thus to couple the
came to the spindle f. Shortly after the alarm has been set in operation the
other finger of the tumbler strikes the pin r, which is stationary, and thus
releases or loosens the brake band o, throwing the brake out of operation and
uncoupling the came from the spindle f. Thus the cam will remain stationary
and the alarm device will remain freed, however, many revolutions the spindle f
may be rotated.
fast
If, however the hand or the cam c is turned by hand in the direction of the
arrow (Fig. 3) the tumbler n will pass the pin and the spring will again
cause the brake bando to couple the cam and brake disc q.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1 An alarm clock, having a coupling between a spindle driven by the
clockwork and the release cam for the alarm device, which is connected to the
hand for adjusting the alarm, characterised by the automatic disengagement of
the coupling after the alarm has been operated, which coupling may only be
re-engaged by hand, substantially as described.
2: In the device of the class covered by Claim 1 the combination of a
release cam for the alarm mechanism, having mounted thereon a tumbler pawl,
said cam being loosely mounted on the clockwork spindle, and a ratchet wheel
fast on the said spindle, and a stationary pin to disengage the said pawl from
its ratchet wheel as soon as the alarm mechanism has been released substantially
as described.
3: A modification of the device covered by Claim 2, according to which the
parts are coupled by means of a brake disc fast on the spindle and a brake
band, the latter being operated by a tumbler lever, on the release cam, normally

page_text: spring pressed to effect the coupling, said lever weig
the coupling by means of a stationary pin in the manner and for the purp
Labetantially
described.
LASH
Dated this 4th day of Decembe
TONGUE & BIRKBECK,
Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.