IMPROVEMENTS IN ALARM CLOCKS
Year: 1885

page_text: COMPLETE SPECIFICATION.
I ARTHUR WILLIAM LOVELL REDDIE of the Office for Patents, 6 Bream's
Buildings, Chancery Lane, in the County of Middlesex, Patent Agent do hereby
declare the nature of the invention for "IMPROVEMENTS IN ALARM CLOCKS," 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 principally to alarm clocks which, for the purpose of
making them of very small size have the alarm bell arranged upon the exterior
of the clock case and have the alarm-striking-mechanism and its actuating spring
within the so arranged bell. In clocks having the alarm bell and its striking
mechanism so arranged, communication must be made, through an opening in the
clock case, between the alarm-striking-nechanism and the trip lever which is
controlled by the time movement within the clock case for releasing the alarm
hammer at the proper time. This communication has been made in some clocks by
making the trip lever long enough to protrude far enough through the opening in
the clock case to reach the alarm-bell, but that length of lever is objectionablo
in clocks the cases of which have their sides or body composed of a hollow cylinder
or polygonal prism made in one piece, as it involves difficulty in putting the
movement into the case.
One object of this invention, so far as it relates to alarm clocks having the
alarm-bell and its striking mechanism and actuating spring årranged as herein
above mentioned, is to avoid the necessity of having the trip lever protrude through
the clock case at all, and to this end one part of the invention consists in providing
the hammer with a downward projection which extends through a slot in the clock
case into engagement with the trip lever which is entirely within the case.
Another object of the invention is to reduce the size of the alarm bell without at,
the same time reducing the size of the alarm movement or its spring. To this end
one improvement consists in constructing or providing the top or upper plate:
of the alarm movement with an upwardly extending and central hub or projection,
having formed within it and on the under side of said plate, a circular cavity,
wherein the alarm-spring is contained. The plates which form part of the frame.

page_text: for the alarm movement are necessarily of greater diameter than the spring, and
the arrangement of the spring in a cavity as described enables the spring to
occupy a position higher up in the bell than would be possible if the upper plate
were flat with the spring below it, and to that extent reduces the size of the bell
necessary to contain the alarm movement.
Another feature of the invention which is not restricted to alarm clocks having
the bell and alarm movement external to the case relates generally to clocks wherein
the alarm index is concentric with the main arbor and which are termed central
setting alarms. In such clocks as heretofore constructed the glass at the front of
the dial (if a glass is used) is set in a sash which must be opened when it is desired
to set the alarm. This movable sash which is generally hinged adds to the cost of
the clock and another object of the invention is to enable a fixed glass to be used
and still have the alarm central setting. To this end the invention also consists in
novel combinations of parts hereinafter described whereby the central setting of the
alarm may be accomplished by a spindle extending through the side of the case.
In the accompanying drawing Fig: 1 represents a partly sectional side elevation
of a clock embodying the whole of the improvements constituting this invention.
Fig: 2 is a front elevation thereof. with a portion of the alarm bell and the
adjacent portion of the case broken away or removed.
...
Fig: 3 is a plan view representing the front plate of the frame of the movement
and the gearing whereby the central setting of the alarm is accomplished, and
Fig 4 is a sectional view in a plane parallel with the main arbor illustrating a
part of the alarm setting devices, and a portion of the dial with their adjacent
parts.
All the views are made on a scale double the actual size of the clock from which
the drawing is made, and in all of the Figures similar letters of reference designate
corresponding parts.
[
A is the body of the case which is shown as consisting of a hollow cylinder of
sheet metal, and B is the back plate of the case which is fitted into the rear part
of the said body and which has the time movement of the clock so attached to it
that the said plate and the movement can be inserted together into the said body.
The time movement forms no part of this invention and therefore only such parts
thereof are shown as are necessary to a clear understanding of the invention. All
other parts may be of any well known or suitable construction.
C is the front plate of the time movement, and D is the main arbor to which is
attached the minute hand d. E is a fixed glass which bears against an inwardly
projecting flange a of the case, and behind which is a bezel or ring b, against which
bears the dial F whereby all said parts are held in place.
G is the hour-wheel having the usual sleeve or pipe G¹ projecting from it and
carrying at its outer end the hour-hand g.
HH are respectively the lower and upper plates which with their connecting
posts c, constitute the frame of the alarm movement. The lower plate Ḥ is
constructed with arms h which are cut or stamped from it, and deflected or bent.
downwards, as shown in Fig: 2 so as to straddle and rest upon the top of the case.
These arms, h, are secured by screws * or other means to the case.
'
The upper plate of the movement has an upward central hub or projection
forming on the underside thereof a circular cavity h' in. which is arranged the alarm
spring e. This spring has one end e* fast in the plate H and by its other end acts
upon the main or winding arbor f of the alarm.
The main wheel e¹ of the alarm-movement drives into a pinion, e² and on the
same arbor with the pinion is an escape wheel e³ which operates the escape pallet e*
on the hammer es, the hammer being pivotted at eº.
In or to the top plate H' is rigidly secured a post or stem f¹ which is shouldered
at f*, and on which is supported the alarm bell L. The bell is held in place by the
nut in which the suspension ring f³ is secured and which is screwed upon the
stem. The winding arbor f extends through the post or stem f¹ which is hollow;
and has at the top a button or head ft wherein it may be turned.

page_text: The extent of the upper plate H₁ is necessarily greater than the size of the
spring, and it is obvious that by arranging the spring in a cavity h' formed by an
upward projection on the plate, the spring is brought higher up in the bell, I, than
would be possible if the spring were on the under side of a flat plate. Consequently
the distance between the plates H H at the posts c is less than it otherwise would
be, and the size or height of the bell necessary to contain within it and conceal the
whole alarm movement is reduced.
It will be observed that the hammer e³ is arranged to work in a horizontal plane,
and has a downward projection or arm e* which extends through and plays in a
slot in the lower frame plate H, and a slot a* in the top of the body A of the
case.
The alarm-tipping and setting mechanism will now be described.
On the outer face of the hour wheel G is a hub having a tooth or projection i
which slopes on one side and which constitutes the tripping cam, and which is
capable of entering a notch * of corresponding form in the alarm cam J when
brought opposite the said notch by the rotation of the hour wheel G.
The alarm cam J is constructed with a sleeve or pipe j which extends through
a central opening in the dial plate F, as best shown in Fig: 4. On this sleeve or
pipe j, inside of and against the dial, is secured firmly a contrate or crown wheel K
and on the said sleeve or pipe, outside the dial are a washer k and the alarm index
or hand ; the end of the pipe or sleeve j being rivetted or turned outwards to
hold all in place. As shown best in Fig: 1 the central portion of the wheel K is
concaved or set back in a direction away from the dial, and its elasticity serves to
hold the alarm cam against accidental turning, the outer portion of the wheel
having frictional contact with the inner face of the dial plate F.
On the front of the plate C of the movement is secured a bracket m as shown in
Fig: 3 in which is journalled a setting spindle or arbor m³, on which is a pinion m³
gearing into the contrate wheel K. The spindle or arbor m' projects through the
side of the case, as shown in Fig: 2, and is provided outside the case with a head
or thumb piece m³ whereby it may be turned to turn the alarm cam J and index
or hand , to release the alarm mechanism at any predetermined hour.
Behind the hour wheel G is the trip lever L which is secured to the plate C and
which has elasticity to cause it to spring outward from said plate. The trip lever,
when the alarm is set, is obtruded in the way of the projection e* on the
hammer e as shown in Fig: 1, and so holds the hammer against operation.
The trip lever is held in this position by the cam projection i bearing on the
face of the alarm cam J but when the tooth or projection i reaches the notch *,
the trip lever L is allowed to spring forward, carrying its upper end out of the way.
of the projection e* on the hammer and allowing the alarm to operate.
It will be observed that the end of the trip lever L does not extend quite to the
cylindric case A and hence it does not in any way interfere with slipping the
movement into place from the back of the case.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed, as communicated
to me by my Foreign Correspondents I declare that what I claim is
1st The combination with a clock case and an alarm bell upon the exterior
thereof, of an alarm movement arranged within the bell and comprising a hammer
arranged to operate in a horizontal plane and having an arm or projection
extending downwards through a slot in the case into the interior thereof, and a
trip lever serving to block the alarm hammer by engaging with the downward
projection thereon substantially as herein described.
2nd The combination with a clock case and an alarm bell on the exterior thereof,
of an alarm movement and a frame therefor, all arranged within the bell, one plate
of the alarm movement having a cavity formed in a hub or projection from its
apper side and containing therein the spring of the alarm movement, substantially
s herein described.

page_text: c3rd The combination with the dial plate F having a central aperture of the
alarm căm J having a sleeve extending through the dial plate, the alarm index on
said sleeve outside the dial plate, the contrate wheel K fast on said sleeve inside
the dial plate and the arbor and pinion m² m² for turning said contrate wheel and
alarm cam substantially as herein described.
4th The combination with the clock case A and the bell I, of an alarm
movement contained within the bell and comprising the plate H having arms.h
which extend downwards and outwards in opposite directions and are attached to
the case, substantially as herein described.