IMPROVEMENTS IN APPARATUS EMPLOYED IN TELEPHONIC SIGNALLING
Year: 1880

page_text: LETTERS PATENT to Edward Hibberd Johnson, of Queen Victoria Street, in
the City of London, for an Invention of ""IMPROVEMENTS IN APPARATUS
EMPLOYED IN TELEPHONIC SIGNALLING."
PROVISIONAL SPECIFICATION left by the said Edward Hibberd Johnson
at the Office of the Commissioners of Patents on the 18th June 1880.
EDWARD HIBBERD JOHNSON, of Queen Victoria Street, in the City of London.
"IMPROVEMENTS IN APPARATUS EMPLOYED IN TELEPHONIC SIGNALLING."
My Invention relates to improvements in that description of apparatus employed
in telephonic signalling in which a moveable hook carrying the telephone receiver
is used for the purpose of automatically controlling the connections and effecting
the signals, and the object of my Invention is to increase the efficiency of such
apparatus, and to obviate the defects to which existing apparatus of this character
are subject.
According to one mode of carrying out my Invention, I retard the movement of
the lever carrying the hook, or a lever or other device in connection therewith, by
the employment of an escapement or equivalent mechanical contrivance, thus
affording the requisite time for making one or more effective contacts between the
signalling battery and the line, whether the hook bo moving upwards or downwards.
This result may be conveniently accomplished by providing on the inner extremity
of the hook lever a toothed segment, which engages with a corresponding toothed
segment or pinion forming part of an ordinary escapement, or the extremity of the
lever may be loosely pivotted to a segmental serrated wheel with which engages the
pallet of the escapement or the extremity of the lever may itself be serrated for the
pallet of the escapement to engage therewith, or the hook lever may be arranged to
operate a trip lever forming part of an escapement, or the retarding movement of
the escapement may be applied to the hook lever in any other usual or suitable
manner.
According to another mode of carrying out my Invention, I cause the hook lever
-by-its-movement to put into circuit an electro magnet which operates the retarding
devices, whereby the same effect is obtained.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Hibberd Johnson in the Great Seal Patent Office on the 14th
December 1880.
EDWARD HIBBERD JOHNSON, of Queen Victoria Street, in the City of London.
"IMPROVEMENTS IN APPARATUS EMPLOYED IN TELEPHONIC SIGNALLING."
My said Invention relates to improvements in that description of apparatus
employed in telephonic signalling in which a movable hook or support carrying the
telephone receiver is used for the purpose of automatically controlling the connec-
tions and effecting the signals, and the object of any said Invention is to increase
the efficiency of such apparatus, and to obviate the defects to which existing
apparatus of this character are subject.
In carrying out my said Invention, I retard the movement of the lever carrying
the hook or support, or of a lever or other device in connection therewith, by the
employment of an escapement or equivalent mechanical contrivance, thus affording
the requisite time for making one or more effective contacts between the signalling
battery and the line, whether the hook or support be moving upwards or down-
wards.
This result may be conveniently accomplished by providing on the inner extremity
of the hook lever a toothed segment, which engages with a corresponding toothed
segment or pinion forming part of an ordinary escapement, or the extremity of the
lever may be loosely pivotted to a segmental serrated wheel with which engages
the pallets of the escapement, or the extremity of the lever may itself be serrated
for the pallets of the escapement to engage therewith, or the retarding movement
of the escapement may be applied to the hook lever in any other suitable manner.
And in order that my said Invention may be perfectly understood, I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheets of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings represents a front elevation of a
signalling apparatus constructed according to one modification of my said Invention.
Figure 2 is a back elevation of a portion of the said apparatus shewing the parts in
a different position to Figure 1, and Figure 3 is a sectional elevation of the
apparatus, the view being taken at right angles to Figure 1. Figures 4 and 5 are
elevations illustrating respectively two other modifications.
c is
Referring to Figures 1, 2, and 3, A is a vibrating lever mounted upon a centre or
fulcrum a in a case B, and terminating at its outer extremity in a hook or
support b for carrying the telephone receiver C, Figure 2, in the usual manner.
a binding screw through which the relay D which brings into operation a bell or
other signalling device (not shewn in the Drawings) is placed in circuit with the
line when the lever A is in the position indicated in Figure 2, with the telephone-
receiver C on the hook or support b. d is another binding screw through which
the telephone receiver C is placed in circuit with the line when the telephone is off
its hook or support b, and the lever A is in the position shewn in Figure 1, the bell
or signalling device being then cut out. E is another vibrating lever nounted upon
a centre or fulcrum e. This lever, when the parts are in the position indicated in
Figure 1, is in contact at its upper extremity with a binding screw f, which places
the transmitter F in circuit, the lever being connected at e to a conductor leading
to the battery G, but the lever is out of contact with the said binding screw, and
the transmitter is consequently out of circuit, when the parts are in the position
shewn in Figure 2,

page_text: The lever E is morcover also usually made with an insulated and an uninsulated.
portion, in order that as the portion h of the lever in its upward and downward
motion passes over the uninsulated portion of the lever E, the circuit being com-
pleted with the line, a pulsation may be sent to the signalling apparatus of the
station to be communicated with. The different connections are clearly indicated
in the Drawing, and being of a well known arrangement, require no special
description. The levers A, E, in so far as they have been already described, form
also a part of arrangements in common use.
Now it is found in practice that the motion of the lever A is too rapid to obtain
such an effective contact with the uninsulated portion of the lever E as will insuro
a marked or well defined pulsation to act upon the signalling device of the distant
station. According to my said Invention therefore, I remedy this defect by
retarding the movement of the lover A, or of a lever or other device connected
therewith, by the employment of an escapement or equivalent mechanical contrivance,
and I thus afford the requisite time for making one or more effective contacts
between the signalling battery and the line, whether the lever A be moving
upwards or downwards. This result may be conveniently accomplished in the
following manner :-
(Figures 1, 2, and 3) is a spur pinion fast on a spindle k, which is carried in
bearings in attachinents 1, l, to the case B. With this pinion engages a segmental
rack m formed on the end of the lever A, so that as the lever moves upwards
cr downwards motion is imparted to the said pinion. On the spindle of tho
pinion is also secured an escape wheel n, with the teeth of which engage the
pallets of an anchor o pivotted at p to the attachments 1, l'; the anchor carries a
perdulum q, the bob r of which may be adjusted in position so as to vary the
velocity of motion of the escapement as required. The escapement thus exercises a
retarding action upon the lever A; so as to prolong the period during which such
lever is moved upwards or downwards, and sufficient time is thereby obtained to
secure a number of contacts, in order to impart if required a series of distinct
pulsations to the signalling apparatus; at the distant station three contacts are
provided for in the example illustrated, the contact points being marked 8, 8, 8.
It is obvious that many other modifications of apparatus constructed upon the
principle of the escapement may be designed for the purpose of carrying out my
said Invention, two additional types of which I have respectively shewn in
Figures 4 and 5 of the Drawings.
In the modification illustrated in Figure 4, the escape wheel n (which in this
case may be segmentally toothed, as she) is attached to the end of the lever A
by a pin t, a slot u being provided in the lever to enable it and the wheel to
perform their respective movements.
The full lines in this Figure denote one extreme position, and the dotted lines
the other extreme position of the lever A.
In the modification represented in Figure 5, an escape rack n' is provided on the
extremity of the lever A, with the teeth of which rack engage the pallets of the
anchor o.
Other modifications will readily suggest themselves to persons skilled in the arts.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that I do not restrict myself to the precise
arrangements hereinbefore described and illustrated on the accompanying Drawings,
as the same may be greatly varied without departing from the principle of my said
Invention, but what I consider to bo novel and original, and therefore claim as
the Invention secured to me by the hereinbefore in part recited Letters Patent

page_text: employment of an escapement or equivalent mechanical contrivance, substantially
as and for the purpose hereinbefore described.
In witness whereof, I, the said Edward Hibberd Johnson, have to this my
Specification set my hand and seal, this 25th day of June, One thousand
eight hundred and eighty.
EDWARD H. JOHNSON. (L.S.)