Year: 1886

page_text: I EDWARD DAVIS of 8 Hockley Hill Birmingham in the County of Warwick
Clock Manufacturer do hereby declare the nature of my said 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 an improved alarm clock of that class in which the
main spring is employed for actuating the time-movement of the clock as well as
the alarm mechanism of the same, the means employed for this purpose being of
simple construction and so arranged as to be within view, whereby the irregular
functioning of the alarm mechanism is avoided.
The invention consists of an alarm driving wheel placed loosly upon said arbor
and taken along by a pawl-and-ratchet device, a pinion keyed to the winding arbor
and meshing with a stop-gear wheel that is provided at one part of its circum-
ference with segmental tooth and adjoining thereto with a recess of a larger size.
A spring attached to the rear wall of the clock frame engages a pin upon the
stop-gear wheel and causes the latter to skip the teeth of the pinion when the main
spring is wound up, so that the pinion and its stop gear are in a position to admit
the working of the alarm-movement when the alarm is liberated.
In the accompanying drawings Figure 1 represents a sectional side elevation of
an alarm clock with my improved alarm mechanism applied thereto. Figure 2 is
a rear elevation of the clock movement. Figure 3. is a vertical transverse section
through the main-spring, showing the winding arbor and alarm stop motion, and
Figure 4 and 5 are detail views of the alarm stop motion, showing it respectively
in position after the alarm has been sounded and in position ready for starting.
Similar letters of reference indicate corresponding parts.
A represents the movement of an alarm clock of that class in which the main-
spring is employed for actuating the time and alarm movements. B is the winding
arbor and C the mainspring, the inner end of which is attached to the arbor while
the outer end is attached in the usual manner, by a stud or other fastening device,
to the main driving wheel D of the time movement.
The main driving wheel D is loose upon the arbor B so as to turn freely thereon
in following the expansion of the mainspring C but connected thereto by the usual
pawl and ratchet wheel. On the other side of the inain spring is located upon the
arbor B the driving wheel E of the alarm movement.

page_text: This wheel is also loose 'upon the arbor B but connected thereto by a pawl e
which is pivoted to the wheel E and kept by a spring in engagement with a fixed
ratchet wheelf on the winding arbor B.
When the arbor B is turned so as to wind up the main spring C the ratchet
wheel skips past the pawle while, when the winding is interrupted, the pawle
engages the ratchet f, and checks thereby the unwinding of the spring. To the
winding arbor B is further keyed a pinion F which meshes with a stop gear F¹
that is loosly mounted on a short independent shaft F that is secured to the clock
frame. The gear wheel F1 is provided at one point of its circumference with
segmental tooth g of nearly twice the length of a common tooth and adjoining
thereto with a recess h which latter is formed by breaking out a tooth on the
circumference of the gear wheel. The segmental tooth g forms the stopping tooth
of the alarm stop motion while the recess h adjoining the stop tooth g permits the
turn of the arbor B when the main-spring is wound up, without being blocked by
the stop tooth g.
To keep the teeth of the stop gear wheel Fin mesh with the teeth of the
pinion F a spring i that is attached to the rear wall of the clock frame presses by
its free end on a pin ' of the stop gear F¹ and returns the latter into mesh with
the pinion F as shown in Figures 2 and 5. Each tooth of the pinion moves the
stop gear F¹ far enough so that the tooth of the stop gear next to the recess his
cleared after which said tooth is moved by the spring i and pin into contact with
the next following tooth of the pinion F as indicated in Figure 5.
The stop gear F does not therefore interfere with the winding of the clock.
Any well known alarm setting and liberating devices may be used in connection
with my improved stop motion which devices require no special description.
Whenever the alarm is liberated at the time for which the same has been set
by the mechanism arranged for this purpose the main driving wheel E of the
alarm-movement actuates the train of gear wheels which oscillate the hammer that
is fast on the pallet-spindle of the escapement wheel of the alarm movement so
that the gong is sounded.
The action of the inner end of the main spring C on the arbor B and the alarm
driving wheel E rotates the latter and turns simultaneously the pinion F. This.
pinion being in mesh with the stop gear wheel F', turns the same in the direction
of the arrow shown in Figure 5 until the stop tooth g abuts against one of the
teeth of the pinion F as shown in Figure 4 and causes thereby the stopping of the
alarm movement. The stop gear wheel F¹ remains in this position until by
the next winding up of the clock the pinion F is turned in the direction of the
arrow marked thereon in Figure 4, whereby the intermeshing stop gear wheel F¹
is returned from the position shown in Figure 4, to the position shown in Figure 2.
In continuing to wind up the mainspring the spring-acted stop gear skips the teeth
of the pinion F as indicated in Figure 5 until the spring is entirely wound up
leaving the pinion F and stop gear F1 in a position for allowing the alarm
movement to be actuated whenever the alarm is liberated. The alarm movement
continues to act during the time in which the stop tooth g moves around from a
position at one side of the pinion F to its position at the other side of the same
when the locking of the pinion F by the stop tooth g and thereby the stopping
of the alarm movement, takes place. The action of the alarm movement and
consequently the unwinding of the inner end of the main spring is thereby
restricted to the distance through which the stop tooth g travels until it comes
around to its stopping contact with the teeth of the pinion F as shown at Figure 4.
It will be seen that the alarm movement is restricted to less than a single turn
of the arbor B so as to require but a small portion of the force of the mainspring
to actuate the alarm movement. If it is desired to use even a smaller part of the
power of the main spring the solid portion g is extended along a greater part of
the circumference of the stop gear F whereby the action of the alarm movement
is restricted to a fractional part of a rotation of the alarm driving-wheel E.

page_text: In my improved alarm stop motion the ringing of the gong is not confined to
one entire alarm driving wheel or to a fractional rotation of the same but the alarm
may be kept striking for several turns of the alarm driving wheel by simply
establishing the proper proportion of the number of teeth of the pinion to the
number of teeth of the stop gear. If for instance the pinion has six and the stop
gear twelve teeth the alarm will be kept ringing for two turns of the driving
wheel while with four teeth of the pinion and twelve of the stop gear the alarm
will be continued for three turns of the driving wheel and so on.
alarm movement is started and has completed its motion it is stopped positively
When the
and uniformly by the stop-tooth 3 when it abuts against the teeth of the pinion.
The resetting of the stop gear F into a position to admit the operating of the
alarm movement is accomplished by winding up the clock as before describe !.
I prefer to arrange the alarm stop motion composed of the pinion F stop gear F¹
and spring i on the outside of the clock frame as shown is Figure 2 instead of at
the inside whereby said can readily be seen and any irregular position be readily
corrected.
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
The combination of the winding arbor B mainspring C and alarm driving
wheel E connected by pawl and ratchet to the winding arbor, of a pinion F keyed
to the winding arbor, a stop gear F¹ meshing with the pinion and having an
enlarged tooth g an adjoining space and a pin i¹ engaged by a spring i attached
to the clock frame substantially as and for the purpose herein set forth.
Dated this 11th day of January 188:
GEORGE BARKER,
Agent for Applicant.