Improvements in and relating to Telegraphic Receiving Apparatus.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to Telegraphic Receiving Apparatus.
I, JOSEPH ARTHUR LOVEL DEARLOVE, of 4, Great Winchester Street,
in the City of London, Telegraph Engineer, do hereby declare the nature of
this invention to be as follows:-
My invention relates to telegraphic apparatus, and more especially to
such apparatus for the reception of messages transmitted over circuits of high
resistance and electrostatic capacity such as long-distance submarine cables and
the like, and comprises certain improvements hereinafter described whereby I
am enabled to render practicable relay working over such telegraphic circuits or
cables at a comparatively high rate of speed.
"
Hitherto it has been usual to receive signals over such circuits by Thomson
recorders or by what is known as the Mirror system" and it has heretofore
been found impossible to employ, with long cables, receiving relays by reason
of the arrival current being inadequate to actuate at a reasonable speed of work-
ing a receiving relay as at present known and constructed. It is true that a
light tongue may be thus sufficiently moved but the contact so made has been
found to be too slight to efficiently and with certainty close the local battery
circuit through either a Morse or other recording apparatus. Moreover with the
code of signals employed where currents of like polarity are successively sent
to line, "sticktion, and a failure to respond to more than the first signal, is
well known.
By my invention I am enabled to overcome these difficulties, and to make
relay working over cables practicable at a comparatively high rate of speed.
In carrying my said invention into practice I adopt the syphon recorder type
of receiver, but instead of using a glass syphon I provide a metallic wire which
may be mounted similarly to the syphon now in use and well insulated from the
body of the instrument. I provide, moreover, one, two, or more adjustable stops
which latter may be fixed in such a manner that on the arrival of a current
from the distant station the metallic wire will approach to one or the other stop
"
"dash" or a
dot." The said wire
according to whether the signal represents a
and stops form part of a highly-charged circuit produced by the use of either
frictional or inductional electricity as in the "Mousemill" and similar apparatus,
or by an induction coil, and the said adjustable stops are arranged in such a
manner that when the metallic wire is deflected a discharge from the wire to
either stop may take place.
35
In conjunction with the above described circuit I may place either one or more
"coherers" of the Branley or any other suitable type, which coherer or coherers
is or are connected in such a manner that, on a discharge taking place between
the metallic wire and one or other of the above mentioned stops the said "coherer'
"coherers" will be actuated, and form a relay to work a local recording or
other circuit, and will be "decohered" in the now well-known manner or in any
other way that may be found suitable.
or

page_text: In some cases I may employ, in lieu of and for the same purpose as the
coherer," a partially exhausted chamber with two balls or electrodes enclosed
therein, and take advantage of the fact that a high discharge through such an
arrangement will open the path for the passage of a current of normal quantity
and potential which may be caused to actuate a local recording or other apparatus
as required.
It will be seen that an important feature of my invention is that I am enabled
thereby to bring into use a local battery by means of which I avoid the necessity
of making actual metallic contact between the moving part actuated by the
received current and such stops as are usually provided in a receiving relay,
and that to effect this purpose I use the metallic wire as a moving part, and thus
in conjunction with high tension currents, and suitably arranged stops, coherers,
partially exhausted vacuum and insulated points mounted therein, or induction
coils, so arrange or adapt the apparatus that a local circuit will be brought into
effective action thereby."
It will be understood that the relay may be adapted for use either for the
reception of signals as at present employed with the syphon recorder, for transla-
tion from circuit to circuit, or in such cases where a typewriter, Morse or other
synchronous systems are in use.
DJ 1
111
1
1
1007
Improvements in and relating to Telegraphic Receiving Apparatus.
I, JOSEPH ARTHUR LOVEL DEARLOVE, of 4, Great Winchester Street,
in the City of London, Telegraph Engineer, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
-
My invention, relates to telegraphic receiving apparatus and more especially to
such apparatus for the reception of messages transmitted over circuits of high
resistance and electrostatic capacity such as long-distance submarine cables and
the like, and comprises certain improvements hereinafter described whereby I
am enabled to render practicable relay working over such telegraph circuits or
cables at a comparatively high rate of speed.
Hitherto it has been usual to receive signals over such circuits by Thomson
Syphon recorders or by what is known as the "Mirror system" and it has heretofore
been found impossible to employ, with long cables, receiving relays by reason
of the arrival current being inadequate to actuate at a reasonable speed of work-
ing a receiving relay as at present known and constructed. It is true that a
light tongue may be thus sufficiently moved but the contact so made has been
found to be too slight to efficiently and with certainty close the local battery
circuit through either a Morse or other recording apparatus. Moreover with the
code of signals employed where currents of like polarity are successively sent
to line, sticktion " and a failure to respond to more than the first signal, is
<
well known.
By my invention I am enabled to overcome these difficulties, and to make
relay working over cables practicable at a comparatively high rate of speed.
In carrying my said invention into practice adopt the syphon recorder type
of receiver and the coil of such instrument is indicated at A in the accompanying

page_text: diagrams. The coil is suspended between the threads a, a¹ and is connected up
between the cable C and earth E either with or without a receiving condenser
intervening. According to my invention, however, instead of using a glass
syphon, I provide a metallic needle B which may be mounted similarly to the
syphon now in use and well insulated from the body of the instrument, that is
to say it may either be mounted on the ordinary syphon bridge or it may be
otherwise arranged so that it may be capable of movement about the pivot point b
under the influence of the directive threads b. In the path of the needle B
and in proximity to it, but not in actual contact with it, are three or more fixed
or adjustable plates D, DI, D². Upon the arrival of an impulse from the distant
station through the cable C the needle B will be moved (owing to the deflection
of the coil A) from over the plate D to over either D' or D² according to whether
the signal received represents a dash or a "dot."
66
"
The needle B and plates D1 and D2 form part of a highly-charged circuit pro-
duced by the use of either frictional or inductional electricity as in the "Mouse-
mill" and similar apparatus, such for example as indicated at F in Figure 1
or by an induction coil as indicated at S in Figure 2, and the said plates D'
and D are arranged in such a manner that when the needle B is deflected a
discharge from it through one of such plates may take place. Normally the
discharge is through the plate D to earth.
In the said highly-charged circuit I place a coherer G which is connected up
in such a manner that, on a discharge taking place through the needle B and
(say) through the plate D¹ the coherer will be actuated. The coherer may take
the form of a closed tube of metallic filings or for the same purpose I may
employ a partially exhausted chamber with two balls or electrodes enclosed
therein, and take advantage of the fact that a high discharge through such an
arrangement will open the path for the passage of a current of normal quantity
and potential which may be caused to actuate a local recording or other apparatus
as required or any other similar or suitable apparatus may be employed. The
coherer may be supported by light rod electrodes H, H'. A small Leyden jar
or condenser K may be connected between one terminal of the coherer and earth
as shown.
L in both diagrams represents the mechanism for decohering the coherer.
Its construction is of any usual or suitable character. As depicted it will be seen
that on each " making" of the local current of the relay M the armature L¹ is
sharply attracted to the poles L2, the extension arms L³ in Figure 1 mounted on
the armature L¹, being serrated to give a vibratory motion to the rods H, H'.
In Figure 2, L is shown as a single-stroke hammer. N represents either the
printer or retransmitter and in the latter case n is its sending battery. P is the
relay battery, and R, R1, R2 and R3 are adjustable resistances.
Upon the arrival of a signalling current from the cable C which (say) repre-
sents a
"dot" the needle B is deflected from over the plate D and comes into
proximity with (say) D¹. A discharge from F or S flows through the needle B
to the plate D and thence through the coherer G to earth, the coherer being
affected and becoming a better electrical conductor. Thereupon the circuit of
the battery G¹ becomes closed, energizing the coils of the relay M, the local
circuit through the tongue m of which, containing a battery P, a printer or
translator N and also the decohering means L, are brought into action. The
printer N or its equivalent either, as indicated in Figure 2, records the dot, or
the signal is retransmitted on to the second section of cable C₁ as in Figure 1.
It will be understood that a similar set of apparatus is required to be connected
with the contact 12, which apparatus is similarly operated by the movement of
the needle B, or alternatively a second needle may be employed for that purpose.
In lieu of the "Mouse-mill" apparatus as described with reference to Figure 1,
I may employ a transformer S the primary p of which is joined up to a battery S¹,
resistance R and interrupter T and the secondary s of which is carried through
the needle B,

page_text: It will be seen that an important feature of my invention is that I am enabled
to bring into use a local battery whilst avoiding the necessity of making actual
metallic contact between the moving part actuated by the received current and
such stops as are usually provided in a receiving relay. To effect this purpose I
use the metallic wire or needle as a moving part, and in conjunction with high
tension currents, suitably arranged plates or stops, coherers, partially exhausted
vacuum and insulated points mounted therein, or induction coils, so arrange or
adapt the apparatus that a local circuit will be brought into effective action.
The coherer G may be worked either in series with the secondary coil s or with
the inductional machine F as shown, or it may be worked as a derived circuit,
in which case the pole E' instead of going to earth direct is connected up to the
plate D¹.
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:-
1. In the receiving circuit of a telegraphic system, the combination of a metallic
needle and a recorder coil so arranged that the deflexion of the coil brings about
the movement of the needle and with it the operation of a highly-charged
circuit through a coherer substantially as set forth.
2. A telegraphic receiving apparatus consisting of a recorder coil and a
metallic needle deflected thereby, a highly-charged circuit of which the said
needle and a coherer form part, and a relay circuit completed through such
coherer substantially as set forth.
3. A telegraphic receiving apparatus consisting of a recorder coil and a
metallic needle deflected thereby, a highly-charged circuit of which the said
needle and a coherer form part, a relay circuit completed through such coherer,
and a local circuit through the tongue of such relay serving as a means for
operating the printing or translating instrument substantially as set forth.
recorder coil and a
4. A telegraphic receiving apparatus consisting of a
metallic needle deflected thereby, a highly-charged circuit of which the said
needle and a coherer form part, a relay circuit completed through such coherer,
and a local circuit through the tongue of such relay serving as a means for
operating the printing or translating instrument and for effecting the decohesion
of the coherer substantially as set forth.
5. The telegraphic receiving arrangement substantially as described and as
illustrated in the accompanying drawings.
Dated this 10th day of September 1898.
A F. SPOONER,
323, High Holborn, London, Agent for the Applicant.