Improvements relating to the Transmission of Signals through Submarine Telegraph Cables.
Year: 1897

page_text: Date of Application, 1st May, 1897
Complete Specification Left, 28th Feb., 1898-Accepted, 9th Apr., 1898
PROVISIONAL SPECIFICATION.
Improvements relating to the Transmission of Signals through
Submarine Telegraph Cables.
I, FRANCIS LAUDER MUIRHEAD, of Princes Street, in the City of Westminster,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in the construction and arrangement of
the apparatus which constitute the subject matter of Letters Patent No. 19183
of 1893.
In carrying out the method of automatic curb transmission described in the
Specification of the said Letters Patent two sets of apparatus are required namely (1)
an automatic transmitter and (2) an intermediate or local transmitter in electrical
connection therewith. The object of this invention is to make the automatic
transmitter readily adjustable as regards the duration of its lever contacts; to
diminish the lag or magnetic inertia of the local transmitter so that the electro-
magnetic shunt used in connection therewith may have a greater range of
control over the movements of the levers of the transmitter in curbing", and
generally to effect the improvements hereinafter indicated.
In carrying out my invention I sometimes construct each contact lever of the
automatic transmitter of one arm only with an upright steel rod loosely jointed
to it at one end, the other end of the arm which makes contact on an adjustable
stop, terminating in a spring contact. In order to regulate the duration of the
contact of the arms of the contact levers with the limiting stops, I may employ an
adjustable stop to limit the distance through which the upright steel rods can
enter the holes of the perforated paper. The more these rods enter the holes of the
perforated paper the longer will be the time of contact of their respective arms
with the limiting stop towards which they are deflected. In the above arrangement
the rocking-beam of the well-known Wheatstone automatic transmitter is made use
of to withdraw the upright steel rods or the contact levers in connection therewith
from the perforations of the paper strip. When the system of contact levers
of the well-known Wheatstone automatic transmitter is used I cause the rocking-
beam mechanism either to act directly on the lever which carries the steel rods or
to act upon the contact making levers themselves and in order to vary the time
during each space when the rocking beam mechanism comes into contact with these
levers I intercept between the rocking-beam mechanism, and the levers an in-
dependent pivotted wedge shaped lever whose position relatively to the rocking-
beam can be adjusted by means of a tangent screw or otherwise. Or sometimes I
employ the bar which depends from the rocking-beam mechanism of the Wheat-
stone transmitter and arrange it so as to act directly upon the lever carrying the
upright steel rods. The upper surface of the lever on which this bar acts is curved
and the point of application of the bar upon the same is varied by varying the
position of two guide pins between which the bar passes. By means of a tangent
screw the block carrying the two guide pins can be adjusted.
Sometimes I may
give motion to the perforated paper strip itself in the desired manner by means
of a rocking beam of special shape actuating a rod which feeds the paper forward

page_text: through the central perforation of the paper strip intermittently. The duration
of the period of rest of the paper is regulated by means of this mechanism according
to the length of lever contact required; or sometimes I impart intermittent motion
to the spur-wheel itself by means of mechanism which can be adjusted without
stopping the transmitter. The mechanism employed to effect the intermittent
motion is so constructed that the period of rest of the spur-wheel between the
passages of the central holes over the ends of the upright rods can be regulated
without stopping the train of the transmitter.
In the construction of the intermediate or local transmitter I substitute for the
two electromagnets described in the said prior Specification two rectangular coils
pivoted between the poles of permanent magnets as in the well-known Kelvin
Siphon Recorder. The two tongues of the transmitter are fixed eccentrically on
the top of these recorder coils and bias is given to them in one direction or the
other by means of two springs attached at one end to the top of the coils respectively,
ending at the other in a loop of silk cord secured to a regulating pin.
Dated this 1st dose of Move 1007
A. F. SPOONER,
323, High Holborn, London, Agent for the Applicant.
Improvements relating to the Transmission of Signals through
Submarine Telegraph Cables.
I, FRANCIS LAUDER MUIRHEAD, of Princes Street, in the City of Westminster,
Electrical Engineer, 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:-
-
My invention consists of improvements in the construction and arrangement of
the apparatus which constitute the subject matter of Letters Patent No. 19,183
of 1893.
In carrying out the method of automatic curb transmission described in the
Specification of the said Letters Patent two sets of apparatus are required, namely (1)
an automatic transmitter and (2) an intermediate or local transmitter in electrical
connection therewith. The object of this invention is to make the automatic trans-
mitter readily adjustable as regards the duration of its levers upon their contacts;
to diminish the lag or magnetic inertia of the local transmitters so that the electro-
magnetic shunt used in connection therewith may have a greater range of
control over the movements of the levers of the transmitter in "curbing", and
generally to effect the improvements hereinafter indicated.
In the accompanying drawings,
Figures 1, 2 and 3 show in three forms or modifications the parts of automatic
transmitters necessary for the explanation of this invention, it being understood
that the clockwork or other operating mechanism, which may be of the usual or
any convenient character, is between the two side plates of the instrument in the
usual way and that in the figure one set only (the foremost) of the two contact
mechanisms is shown although there are two precisely similar sets employed, one
located behind the other.
Figure 4 is a plan of my improved local transmitter.
Figure 5 shows the instrument in elevation removed from its outer casing, and
looking in the direction of the arrow in Figure 4, and
Figure 6 shows the instrument in elevation part being in section and with the
magnet s removed.

page_text: Figure 7 is a diagram to aid the understanding of the invention.
The action of automatic transmitters being well-understood the same need not
here be explained beyond stating that a paper strip previously punched with a
central line of equi-distant holes and with side perforations, is fed through the
instrument, the spur wheel a engaging with the central line of holes and the side
perforations governing the movements of the contact levers of the instrument.
According to the first part of my invention I may construct each contact lever of
the automatic transmitter either in one part as shown in Figure 1 or compound as
shown in Figures 2 and 3, but in each form the arrangement is such that improved
means are provided for readily varying the effective distance between that part
of the lever mechanism which enters the side perforations in the paper strip and
that part which effects the electrical contact, so as to render their correlative move-
ments adjustable and thereby varying the moment and duration of contact between
the lever and its stop or stops.
C
In Figure 1b is the lever contact pivoted at b' and terminating in a spring
piece 62. The lever b carries the loosely-mounted upright steel rod c the extremity
of which enters the perforations in the paper strip in the usual way. The spring d
pulls the lever 6 towards the stop but the bar e, presently to be described, or
the paper strip, resists the pull of such spring until the said rod is raised by the
mechanism, which raising is timed to occur when a perforation is (or might have
been) immediately over the upright rod c. The said rod c is maintained under the
influence of a spring c¹ but the pull thereof is resisted by the adjustable stop c².
f is a bell-crank lever pivoted at f¹ and operated through an excentric f2 and
connecting rod f3 by the rocking-beam mechanism of a Wheatstone automatic
transmitter. The bar e is dependent from the extremity of the bell-crank lever f
but it passes freely through a pivotally mounted bearing e¹, which latter is located
upon a sliding guide-frame g. It will be observed that the point--and therefore
the period of contact of the bar e upon the surface of the contact lever b can be
varied by altering the position of the guide-frame by means of the tangent
screw h. The surface of the contact lever b upon which the lower extremity of
the bar e rests is shown curved or sloped in the drawing to avoid a too rapid
adjustment, though such arrangement is but optional. In addition to the adjust-
ment available at this point the battery contact x is itself mounted at the end of a
similar tangent screw h¹ and is thereby rendered adjustable. The battery contact
is shown insulated by a non-conducting piece a¹. Obviously in cases where the
contact levers are required to operate on two stops a second stop similar to the
oner is fixed on the other side of the contact levers.
In Figure 2 each contact mechanism is made in two parts, that is to say is a
compound one. The one part f4 is pivoted at the point f5 and carries a rod cas
before. The other or contact part proper is of similar form to that described with
reference to Figure 1 but it, together with the limiting stops, y,
is mounted upon
a non-conducting sliding block i adjustable by means of a tangent screw h³.
Between that part of the lever mechanism f* (which is shown sloped or wedge-
shaped) and the part b, and mounted on the latter, is a stop j, and it will be seen
that the effective distance between the two parts,. and consequently the moment
and period of contact of the lever b, is governed by the adjustment of the sliding
block and thereby the position of the stop j relatively to the lever f. In this
Figure the pin k, actuated by the rocking beam mechanism, serves to lower the
rod c after it has entered a perforation in the paper strip and to resist at other
times (except when a perforation in the paper strip comes, or might have come,
above the rod c) the pull of the spring d¹.
When the system of contact levers of the well known Wheatstone automatic
transmitter is used I may cause the rocking beam mechanism either to act directly
on the levers which carry the steel rods or to act upon the contact making levers
themselves and in order to vary the time during each space when the rocking beam
mechanism comes into contact with these levers I intercept between the rocking
beam mechanism and the levers an independent pivoted wedge shaped lever whose

page_text: position relatively to the rocking-beam can be adjusted by means of a tangent
screw or otherwise. But I prefer to simplify the construction of the transmitters
made according to this invention by substituting for the levers which carry the
steel rods, levers I made in one piece and of shape as shown in Figure 3. In this
case I provide for each set a wedge or mitre ended lever or arm m which is pivoted
at m¹ and adjusted in its relation to the lever by means of an excentric n.
Between
the arm m and the contact lever b is a sliding rod or bar p. The duration of the
contact lever b on the limiting battery stops a, y depends upon the height to which
the wedge shaped terminus of the lever m is adjusted by means of the excentric n
relatively to the similar terminus of the lever l.
The intermediate or local transmitter or relay consists, as seen in Figures 4, 5
and 6, of a circular or suitable base q from which rises a cylindrical metallic
or other suitable casing q' and a glass topped cover or lid r. The working parts are
all contained upon a separate block as clearly shown in Figure 5 where one of the
usual magnets s is seen. For the two electromagnets of the polarized relay des-
cribed in the said prior specification, I substitute two rectangular or other suitable
coils of wire within each of which is a fixed soft-iron core u. The said coils t
16
are retained between the poles of the said permanent magnet s; they may be
pivoted in suitable bearings in a manner similar to the like coil used in the well-
known Kelvin siphon recorder or they may be suspended bifilarly by silken or
other threads as shown at t¹, t2 respectively. The lower cords pass over guide
pulleys t³, and are attached to a regulating pin v. Springs to, to may be interposed
if required. By turning the regulating pin v the suspension is tightened or
loosened. Upon the top of each coil t the tongue w of the local transmitter is
mounted and it plays between two adjustable limiting stops w¹ and w². The
springs and serve to give bias in one direction or the other to the said
tongue.
I find that by the substitution of the pivoted or suspended coils (and especially
with the bifilar suspensions described) for the electromagnets of the said prior
specification, a much more effective instrument is obtained.
The essential part of the arrangement for transmitting signals into a cable is
depicted in Figure 7. For simplicity a hand-signalling key is there shown but it
will be understood that an automatic transmitter may be substituted.
The coils t, t are joined up in series with a local split battery 1, 2 and signalling
key or its equivalent 3. Between the two coils t, tan electromagnetic shunt 4 is
joined up so that on the cessation of current from either part of the split battery
a reversed or induced current flows through the coils and actuates the tongues w, w
in the reversed manner and thus to send a reversed or curbing current into the
cable. Thus, on depressing, for example, the left hand lever of the key 3 a zinc
current flows through the coils t,t actuating the left hand tongue and thus
sending a copper current from the line battery 5 to the cable or line. On allowing
the said key lever to return to its normal position the current from the local
battery ceases in the coils t, t and the induced current which succeeds it actuates
the right hand tongue w thus putting the cable or line to the zinc pole of the line
battery. By regulating the amount of self-induction in the shunt 4 in any of the
well-known ways the amount of curbing current relatively to the original or
primary current can be varied.
Having now particularly 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 :-
1. In an automatic telegraph transmitter, means, substantially as set forth,
serving to vary the effective distance between that part of the lever mechanism
which enters the side perforations of the paper strip and that part which effects
the electrical contact, so as to render their correlative movements adjustable and
thereby to vary the moment and duration of contact between the lever and its
ston

page_text: 2. The automatic transmitter made substantially as described with reference to
Figure 1, or to Figure 2, or to Figure 3 of the accompanying drawings.
3. In an intermediate or local telegraph transmitter or relay, the coil t either
pivoted or suspended substantially as set forth.
4. An intermediate or local telegraph transmitter or relay comprising two or
more coils of wire such as t, a tongue as w upon each coil, a soft iron core as u
within each coil, suspending threads as t¹, t, guide pulleys as t3, t and means for
regulating the tension of the said threads substantially as set forth.
5. The improved intermediate or local telegraph transmitter or relay constructed
substantially as set forth and as illustrated in the accompanying drawings.
Dated this 28th dor of Rohm 1808
A. F. SPOONER,
323, High Holborn, London, Agent for the Applicant.