AN IMPROVED CUT-OUT FOR TELEPHONES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents on the 27th October 1883. Com-
municated to him from abroad by Oliver Benjamin Carter, John Thompson
Fouche, Charles Andrew Fisher and Charles Douglass Wright all of Petersburgh
in the county of Menard and State of Illinois, United States of America
ALEXANDER MELVILLE CLARK of the firm of A. M and W. Clark of 53 Chancery
Lano in the County of Middlesex Fellow of the Institute of Patent Agents "AN
IMPROVED CUT-OUT FOR TELEPHONES" [communicated to him from abroad by
Olivor Benjamin Carter, John Thompson Fouche, Charles Andrew Fisher and
Charles Douglass Wright all of Petersburgh in the county of Menard and State of
Illinois, United States of America]
The object of this invention is to provide a new and improved device for cutting
out all the resistances and telephones on a line between the two telephones which
are to be in communication.
This improved telephone cut-out consists of a clock train combined with a circuit
closer whereby when the train is set in motion the line current is short circuited
and the transmitter and receiver are consequently cut out; a local battery and an
electro magnet in the circuit thereof whose armature is combined with a detent
whereby the clock train is normally held arrested; and a circuit closer in the local
circuit adapted to be operated by the call bell hammer of the telephone in such
manner that when the call bell is operated by the line current, the local circuit is
closed whereupon the electro-magnet by attracting its armature withdraws the
detent thus releasing the clock train which being thereupon set in motion short
circuits the line current thus automatically cutting out the telephone.
The clock work actuates an index hand showing on a dial when and how long
the instrument has been cut out, and upon the same arbor is fixed a notched disc
acting as a cam, against which presses a stud carried by a spring which is connected
with one terminal of the telephone, and whose free end is adapted to be pressed
against an insulated contact connected with the other terminal. So long as the
stud remains in the notch of the disc the spring is held back from the insulated
contact, but immediately the disc commences to be rotated by the clock train the
stud is lifted out of the notch and the spring is pressed against the contact, thus
short circuiting the line current and cutting out the telephone, until the stud

page_text: again falls into its notch whereupon the contact is broken and the telephone is
again brought into the Circuit. The detent which arrests the clock train consists
of a three armed lever the several arms of which are adapted to engage with
notches in three several wheels of the clock train, and the tail end of this lover
forms an armature for the electro magnet.
The circuit closer of the local circuit consists of two levers pivoted on an
insulated support and pendent in close proximity to one another and to one side of
the call bell hammer. Theso levers are respectively drawn against insulated studs
by springs which respectively connect the levers with the opposite poles of the local
circuit. The levers are provided on the adjacent faces of their free ends with
contacts made of pieces of platinum wire fixed longitudinally on the one and
transversely on the other so as to ensure perfect contact. The levers and their
studs and springs are so arranged with respect to the hammer that when the latter
vibrates it will strike an insulating strip fixed to one of the levers and cause said
lever to come into contact with the other lever thus closing the circuit of the local
battery through the electro-magnet which by attracting its armature releases the
clock which actuates the circuit closer that cuts the telephone out of Circuit as
above described.
The several telephones in the same line circuit may be distinguished by numbers
so that any particular one may be called by a corresponding number of strokes of
the call bell. All the bells will be sounded and all the telephones on the circuit
will be cut out including the one called but by lifting the transmitter from the
hook his instrument is again brought into Circuit.
The conversation carried on between two telephones cannot be overheard at
intermediate telephones as they are cut out.
The above described device can also be used in connection with a switch board
where annunciators with covers are used in place of bells, the pawl which holds the
cover up being used to bring the levers of the lino circuit closer in contact.