An Improved Electric Central Alarm or Call Apparatus.
Year: 1894

page_text: COMPLETE SPECIFICATION.
An Improved Electric Central Alarm or Call Apparatus.
I, CONRAD CHRISTGAU of No. 1 Kirchenstrasse, Scharmbeck, near Bremen,
in the German Empire, Hotel Proprietor, 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 an electric alarm or call apparatus for hotels and similar
institutions, the object of which is to operate a bell or bells in a certain room or
rooms from a central clock at four short intervals at any desired time or at
various times.
In order that my invention may be the better understood, I now proceed to
describe the same, reference being had to the accompanying drawings and to the
letters and figures marked thereon.
The drawings Figs. 1 and 2 show a back elevation of the central clock and
adjoining switch board with a diagrammatic view of the circuits, and Fig. 3 is a
transverse section of the switchboard through line a―b.
. On the back of the central clock a are arranged 48 contact pieces 6 on an
insulated ring preferably made of india-rubber. These 48 contact pieces correspond
to the 48 quarter hours during one revolution of the hour hand c. The hand c
attached to the hollow hour spindle or arbor slides over the contact pieces b and
closes on them the circuit, every quarter of an hour. As soon as the clockwork
operates the disengaging lever of the striking mechanism upon the striking of the
quarter hour, the circuit is closed at this place at the same time by means of two
leverse and f; one above the other, the lower levere being insulated on its
lower side by vulcanised india-rubber, and lifted by the disengaging lever of the
striking mechanism, thus making contact with the upper lever f. It is necessary
for this purpose, that the striking mechanism is not disengaged five minutes, as is
usual, but only one minute, before striking each quarter hour. In order to operate
the alarm apparatus four times during this minute, the circuit is continued to
a sliding contact g, situated over the seconds wheel of the clock work. For
this purpose the seconds wheel h is provided with four pins at equal intervals
on the periphery, which, in consequence, effect the closure of the circuit a similar
number of times during the rotation of the wheel, by means of the sliding
contact g.
l
Each of the before-mentioned contact pieces b on the insulated ring of vulcanised
india-rubber is connected with corresponding contact strips i of copper on a contact
or switch board k situated beside the clock. Below these contacts i, and insulated
from one another, there are situated as many concentric copper rings as there are
rooms in which a bell is to be placed. The radial contacts as well as the
concentric rings of the contact or switch board kare. perforated at their
crossing points, placed above the other. Into these perforations is placed a
plug for switching on a certain room.
As shown in the diagrammatic view of the circuits, the current passes, at the
striking of each quarter hour from the battery m, in the room concerned, over the
bell mechanism n in such room, to the copper ring provided for such room on
the switch board k, thence to the plug of the quarter hour contact i of the switch
board, connected to the corresponding quarter hour contact 6 of the clock, thence
over the double lever ef of the striking mechanism to the sliding contact g of the
seconds-hand, back to the other pole of the battery m.

page_text: Having now particularly described the nature of this invention and in what
manner the same is to be performed, I declare that what I claim is :-
An electric central alarm apparatus, consisting of a central clock with three
contacts be g of which the first is effected by the hour hand, the second by the
disengaging lever of the striking mechanism, and the third by the second hand of
the clockwork, whereby an alarm or bell is sounded in a certain room switched on
by a switch board beside the central clock at a certain desired time, also
indicated on the switch board.
Dated this 12th day of April 1894.
FELL & WILDING,
Agents for the Applicant.