Improvements in or applicable to Clocks for Operating Electrical Alarms.
Year: 1894

page_text: Date of Application, 29th May, 1894-Accepted, 21st July, 1894
COMPLETE SPECIFICATION.
Improvements in or applicable to Clocks for Operating Electrical
Alarms.
I FERDINAND FRITZ, of No. 115-116 Leipziger Strasse, Berlin, in the Empire
of Germany, Gasburner Manufacturer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
My said invention which relates to clocks for controlling electrical currents is
distinguished by the arbor carrying the hour hand being solid and working inside a
hollow shaft which carries the minute hand and allows the clock to be set by means
of the hour hand as well as by the minute hand as heretofore.
On the arbor of the hour hand I fix a revolving contact arm which is carried
round an indicator plate at the back of the clock. In the indicator plate are seated
terminals of wires connected from a separate keyboard by means of which any
desired alarm may be rung at any desired hour.
In the accompanying drawings
Figure 1 is a perspective view of the clock and indicator plate.
Figure 2 is a side view seen from the back or left hand of Figure 1.
Figure 3 is an elevation of the back plate of the clock motion showing the upper
end of the pendulum. In this view the indicator plate and its connections are
left off.
Figure 4 is a section showing the arrangement of the arbors of the hour and
minute fingers.
Figures 5 and 5^ are respectively end and side elevations of the keyboard for
making the desired connections.
In accordance with my said invention the hour hand is fixed on the free front
end of a solid arbor a instead of being mounted on a bush or hollow shaft (in com-
bination with the driven hour wheel) as is the case in ordinary clocks. The
arbor a goes through the hollow driving shaft b of the minute hand j (Figures 2
and 4) and is prolonged through to the back where it carries an arm c for making
electrical contacts. The angular position of the arm c on the indicator plate d
corresponds therefore to that of the hour hand. The arm c is provided with a
spring end piece hinged at c¹ for making contact at x x with the electric terminals
in the indicator plate d.
The hour arbor a is driven by a pinion e gearing into a toothed wheel on the
spring barrel. The pinion e is not fixed to the arbor a but only takes it round
by friction. For this purpose the pinion e (which is attached to the toothed
wheel g controlled by the escapement wheels) takes against a conical journal or
shoulder on the arbor a and is held up by a disc h.
The action of the spring barrel on the pinion e only takes place under the
control of the escapement k controlled by the pendulum o. Assuming therefore
the clock to be provided with a suitable escapement mechanism the arbor a will
rotate at its proper speed. By means of the wheelwork p, q, r, s, the twelve fold
increased motion of the hollow minute shaft bis derived from the hour arbor a.
By this arrangement the position of the hand can be regulated by shifting the
hour hand itself (or the arm c) and the minute hand will then automatically
revolve. The setting of the clock hands is not only more rapidly accomplished
than in ordinary clocks where the setting is effected by means of the minute hand
but is more certain inasmuch as there is no risk of wrong setting by accidentally
touching the hour hand of the ordinary construction or producing back play in
the hand. From this arises the advantage which my said invention possesses

page_text: that when in combination with a contact arm c the latter moves in the same
manner as the hour hand and can be used directly for setting the clock. The
metal roller mounted in bearings on the spring part c' of the contact arm c
(Figure 2) passes over the successive terminals on the disc d which may be
-disposed either to correspond to the hours as shown in the drawing or in any
-other convenient way. Each terminal belongs to an electric circuit which has
to be closed at a certain time, e.g. Figure 1 shows the clock as a time keeper
for an electric alarm arrangement working in combination with the keyboard m¹
shown in Figures 5 and 5. The wires have terminals in separate hooks a³ which
are joined by flexible connections to connecting pieces which conduct the
current to the alarms c'. The hooks a' serve to hold the rings of the flexible
connections when not in use.
The hooks a² may be arranged for different intervals of time and correspond
to the divisions of the indicator plate d. If for instance the circuits for the
alarms 1, 2, and 5 are to be closed at two and five o'clock the rings are put ou
the appropriate hooks a² when the circuit is completed from the clock to the
keyboard and the alarms and thence to the battery B.
The return wire of all the circuits to the one battery is attached to the clamping
piece which also holds the piece m made of strong wire which is suitably insulated
from the clockwork and by means of which the contact arm c becomes a conductor.
of the current. For this purpose the free end of the piece m bears against a
metallic boss n connected to the contact arm c (Figure 2). This boss can be
insulated from the arbor a and therefore from the clockwork. The reversed
position of the clamping piece in which the circuit between m and n is interrupted
is shown in dotted lines in Figure 3.
'
The upper part of the pendulum o must be provided with a slot o¹ as shown in
Figure 3 when the pendulum is hung centrally just over the arbor a for the latter
to pass through. The lateral extensions of the slot allow the pendulum to swing.
This arrangement is not necessary in clocks where the pendulum is placed at one
.side or in clocks having a balance escapement.
By means of a plate connection 6' all the alarms may be connected.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
.claim is.-
I. A clock having an adjustable hour hand secured on a solid arbor (passing
through a suitable slot in the pendulum and through the indirectly driven bush
which carries the minute hand) frictionally driven from the pinion e and carrying
at the rear end a contact arm c (provided with a contact roller c²) round an
indicator disc d for directing an electric current from the piece m (hinged at land
bearing on the shaft a) to such of the hooks a² of the keyboard m' as correspond to
the terminals & on the disc d, when the arm c makes contact therewith, and thence
by means of flexible conductors (having rings v) to the alarms 1 to 5.
II. The combination of a clock and keyboard as set forth in Claim I with a
plate contact 1 for operating all the alarms simultaneously.
Dated 28th day of May 1894.
E. T. WHITELOW, A.M. Inst. C.E.,
70, Deansgate, Manchester, Agent for the Applicant.