AN IMPROVED ELECTRIC ANNUNCIATOR
Year: 1885

page_text: I FREDERICK WALKER of 36 Spondon Road, Tottenham in the County of
Middlesex Engineer, do hereby declare the nature of my Invention for "AN
IMPROVED ELECTRIC ANNUNCIATOR," to be as follows:-
The object of my invention is to produce an electrical annunciating contrivance
or device in which contact is not dependent upon the tension of any description of
spring whatever, but upon a constant force which is not affected by changes of
temperature, nor weakened as in the case of a spring.
In carrying out my invention I employ a weight, which being held in a given
position, causes the electric circuit connecting the bell with the annunciator to be
broken; and, upon said weight being released, it resumes its normal position, and
making electrical contact, rings the bell in connection with the annunciating
device or contrivance aforesaid.
The weight above referred to may be attached to a lever or to levers in such a
manner as to permit of a considerable range of movement as compared with that of
the contact itself.
I may also arrange said weight, lever or levers, and contact, either vertically, or
horizontally; to serve as an electrical alarm attachment for windows, doors, safes;
also, to serve as "floor contacts"; and generally, to replace any electric annun-
ciator wherein contact is effected by the tension of a spring, irrespective of the
application to which the device or contrivance according to my invention may
be put.
JAMES STEVENSON,
Agent for Applicant,
26, Paternoster Square, E.C.

page_text: An Improved Electric Annunciator.
I FREDERICK WALKER of number 36 Spondon Road, Tottenham in the County
of Middlesex, Engineer, do hereby declare the nature of my invention for AN
IMPROVED ELECTRIC ANNUNCIATOR and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
The object of my Invention is to produce an electrical annunciating contrivance
or device in which contact is not dependent upon the tension of any description of
spring whatever, but upon a constant force which is not affected by changes of
temperature nor weakened as in the case of a spring.
In carrying out my Invention I employ a weight which being held in a given
position causes the electrical circuit connecting the bell with the annunciator to be
broken, and upon the said weight being released, it resumes its nomal position,
and making electrical contact, rings the bell in connection with the annunciating
device or contrivance aforesaid.
The weight above referred to may be attached to a lever or to levers in such a
manner as to permit of a considerable range of movement as compared with that
of the contact itself.
I may also arrange said weight, lever or levers and contact either vertically or
horizontally to serve as an electrical alarm attachment for windows, doors, safes,
also to serve as "floor contacts" and generally to replace any electrical annunciator
wherein contact is effected by the tension of a spring irrespective of the application
to which the device or contrivance according to my invention may be put.
Referring to the accompanying sheet of drawings: Upon a base plate D, D of
metal or other suitable material is pivoted at c, a bar b carrying at its extremity a
weight a which protrudes through the base plate D as shewn upon the section at
Fig. 2. A strip of vulcanite, wood, or any insulating substance d is screwed to the
base plate, to which strip d is attached a small band of brass or other metal e in
such a manner that when the base plate D is placed in a vertical position the
action of gravity upon the weight a causes the other extremity of bar b to make
electrical contact with the insulated strip e; such contact being broken when the
weight a is pressed inwards. In arranging for perfect and non-oxidisable contact
between bar b and strip e platinum, or other suitable substance may be employed.
Electrical connection with the circuit is made at ƒ and g respectively; the method
of employment is as follows:-The base plate D being let in to the jamb of a
door or the sash of a window, the closing of a door or window depresses the
weight a and breaks electrical contact at e and such contact remains broken while
the door or window remains shut. Should however the door or window aforesaid,
or other object with which the apparatus according to my Invention is connected,
be opened, the weight a springs forward, by reason of gravitation, and the electrical
contact is established at e, ringing the bell or other signalling apparatus which it
may be desired to work.

page_text: By means of my invention the necessity for a spring is entirely dispensed with,
springs being always liable to strain whilst under constant tension, and frequently
break during changes of temperature; and further, experience having shown that
springs are not reliable for such applications.
Having now particulary 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 electrical contrivance or device to be employed for annunciating purposes,
substantially as herein described and shewn in the accompanying sheet of
drawings.