Improved Methods of and Apparatus for Transmitting Signals or Electric Impulses.
Year: 1893

page_text: Date of Application, 1st May, 1893-Accepted, 1st July, 1893
COMPLETE SPECIFICATION.
[Communicated from abroad by CHARLES CUTTRISS, of Drexel Building,
New York, United States of America, Electrician.]
Improved Methods of and Apparatus for Transmitting Signals or
Electric Impulses.
I DAVID YOUNG, Patent Agent of the firm of D. Young & Co. 11 & 12
Southampton Buildings in the County of London, 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 :-
The invention which forms the subject of my present application for Patent is
an improvement in methods of transmitting or controlling the transmission of
electric signals or impulses and in an automatic transmitter for telegraphic systems,
but more particularly designed and adapted for use with submarine or other
insulated cables, by reason of certain features of its construction devised for
conditions that are not met with to any appreciable extent in other systems of
signalling. I shall therefore illustrate my inprovements as applied to cable
transmission. The invention pertains to that class of transmitters in which the
action of the circuit-controlling devices is controlled by a travelling perforated
strip or tape or one of the equivalents therefor, such as a tape with mere
indentations instead of perforations, or having points or portions of its surface
raised or specially prepared so that a trailer in contact with the moving surface
will make or break the circuit whenever it encounters such points or portions
of surface, and it will be understood that when reference is made hereinafter to
a perforated tape, it is as the equivalent of the forms described.
A serious defect common to all automatic transmitters of the class to which my
invention pertains is the liability of the contact points to oxidation and the
difficulty of maintaining them free from impairment due to this and other causes,
mainly the sparking when the points separate in breaking circuit. To remedy
this I interpose between the contacts which make and break the signalling current,
or which control the sending of positive and negative impulses to line, a circuit-
controller which will interrupt the circuit completed through the one or the other
set of said contacts before such contacts separate, in this way transferring the
spark to points which may be made much less delicate, and which may be more
readily got at for repair or removal.
Another object of my invention is to impart to a perforated paper strip used
for operating the trailers of an automatic transmitter, a positive and intermittent
movement and to so arrange the instrument that the signals or impulses which
are caused by the trailers dropping into perforations in or encountering projections
on the paper will be sent during the periods of rest of the paper only. It results
from this that I obtain signals that are much more distinct and clearly defined
than those sent by hand or by any other transmitter of which I am aware.
I have also devised special means for indicating and controlling the rate of
transmission, and for adjusting the duration of earth contact, and in several other
particulars to be more fully hereinafter described I have improved the construction
of the apparatus.
In the accompanying drawings
Fig. 1 is a top plan view of the apparatus.
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page_text: t
Fig. 5 is a similar view of the same in a different position.
Fig. 6 is a horizontal section of the parts in Fig. 4 on line y-y.
Fig. 7 is a diagram of the circuits and devices for controlling the same that are
directly concerned in the transmission of signals: **
Fig. 8 is a diagram of the regulating devices and circuits employed in connection
with the motive power for actuating the transmission.
"
The diagram Fig. 7 will illustrate the main objects of the invention. In this
figure A B designate two keys that work between two conducting bars A" B"
which form the terminals of the line battery C, both being normally in contact
with one of these bars, as for example the bar B1 which is connected with the
negative pole of the battery. One key, as A, is permanently connected with the
cable, the other to earth. This is the ordinary arrangement of cable keys, and it
will be seen that the cable is connected with earth whenever both keys A B are in
contact with bar B"; that a positive current will go to: line when key A is down
and key B up and a negative when key B is down and key A up.
I place under each key an electro-magnet A' and B¹ and connect them with
branches of a local circuit that run to the trailers a, b of the transmitter.
These latter maintain the circuits or branches normally open, but when one or the
other is moved so as to touch its appropriate contact a" or 6 the magnet in the
branch thus closed will operate its key and as long as such circuit remains closed a
positive or negative current, as the case may be, is sent to line. The moment the
circuit of such magnet is broken either by the trailer or any other device the
current to line ceases and the cable is grounded.
The trailers are light and delicate levers and one of the main difficulties in the
practical use of machines of this character is in keeping their contact points clean
and perfect. To prevent, therefore, the occurrence of sparks between them,
I include in the part of the circuite which extends from the back contacts to the
magnets A¹ B¹ and which includes the local battery C, a circuit-breaker consisting
of a spring bar D' bridging two terminals in the circuit and which is adapted to he
raised out of contact with one terminal by a cam. By means hereinafter explained
the action of the cam is so timed with respect to the period within which the
trailers may be in contact with their stops, that the circuit is broken by the bar D
before the trailers leave their stops. It is evident that the sparking is thus con-
fined to a single contact which may be made of substantial form and easily renewed
and repaired. The spark may also be reduced by the employment of a high
resistance coil forming a shunt around the contact points.
་
Referring now to Figs. 1.to 3, E designates the armature of any suitable motor,
but preferably an electro-magnetic motor with permanent field magnets D₁ the
shaft E of which is mounted in suitable bearings in standards E".
"
On the shaft E¹ is a worm thread or cam Ę that engages with a wheel Fi
provided with peripheral teeth or pins, the relations of these two elements being
such that every revolution of the shaft E' imparts to the wheel F¹ during the
period of the engagement of its worm thread therewith a movement through the
space of one tooth, allowing it to remain stationary during a portion of the period
of each revolution determined by the character or break in the worm thread
or cam.
The wheel F is carried by a shaft F" upon which, and generally outside the
case of the instrument, is fixed a wheel G provided with a like number of pins g
correspondingly placed. In the periphery of this wheel are a series of perforations
or indentations g g on opposite sides of the line of pins.
The trailers a, b are right-angled metallic levers pivoted side-by-side in an
insulating block e, and carrying in their ends pins e with points bevelled on the
forward side, and lying directly over the lines of perforations in the wheels G.
To the vertical ends or arms of the trailers are connected spiral springs f to an
arm extending from the block e, and by the adjustment of these springs the
horizontal ends of the levers are forced downward so that the pins el have a
tendency to enter the perforations in the wheel G. A presser blade f" is secured

page_text: to the block e and bears upon the periphery of the said wheel, being property
to permit the passage of the pins g and the play of the pins el.
A bifurcated arm or plate H is pivoted to the side of the case or frame of the
instrument and when in its normal position its two arms lie on opposite sides of the
wheel G and on a level with the uppermost edge of the same.
The paper strip or tape K is made with a central line of equidistant per-
forations h. It is then prepared for the transmitter by a suitable perforating
machine which forms two lines of perforations or indentations h¹ on opposite sides
of the central line of perforations, the side on which the perforations occur
depending upon the direction of the impulses which they are designed to transmit,
but every perforation is exactly in line with one of the central perforations, or at
a point in some other definite and fixed relation thereto.
A tape thus prepared is led through a guide L and is drawn over the wheel G
under the presser blade f" and with the pins a passing through the central line of
perforations. The motor being then started the wheel G is rotated intermittently,
the period of rest being so timed as to occur at the moment when the pins el come
over the perforations ¹g". If there be no perforation in the paper under either
pin they are prevented from dropping down, but whenever a perforation occurs
one of the pins passes through the paper and causes its lever to touch its
contact all or
On the shaft Eis fixed a sleeve D' having a raised portion L' which serves as
When by the
a cam to engage with a lug l' on the under side of the bar D.
rotation of the shaft E' the lug and projection I' are in engagement the bar D
is raised from one of the terminals which it bridges. The edge of the pro-
jection L' which meets the lug is oblique to the axis of the shaft, while the other
edge or that which the lug leaves after passing over the projection is straight
or parallel to the axis, so that by adjusting the bar D bodily at right angles to the
axis of the shaft the period of engagement between the lug and projection L' may
be varied according as the lug passes over a narrower or wider part of the projection.
The relative positions of the projection or cam L' and the worm F are such that
the bar D will be raised to interrupt the circuit through either magnet A¹ or B₁
during the periods of rest of the wheel G and the tape which is moved thereby, and
prior to the time when either trailer, if it be in contact with its backstop, can be
separated therefrom by the advance of the tape. The, occurrence of such inter-
ruption, therefore, with relation to the time of separation of the trailers from their
contacts is fixed, and always precedes such separation, but by the adjustment of
the bar D, above described, the duration of the bridging of the terminals ii by the
bar D may be varied as may be found desirable. Thus the circuit may not be
completed until more or less time has elapsed after a trailer has made contact,
the duration of contact being thus regulated according to the requirements of
working.
To arrest the movement of the tape, without interrupting the motor, I pivot the
block e to the side of the casing or frame, maintaining it in operative position by a
spring N attached to the frame and to an arm m fixed to the block. This spring
also serves to depress the plate H which is .acted upon by a spring m¹ but which is
held down by a block m" that impinges against the under side of the block e
forward of its pivot. By means of any suitable device such as a detent N' the
arm m is shifted and held against the force of the spring N which raises the
trailers and plate H, as shown in Fig. 5, and lifts,the tape from the wheel.
I have shown in connection with the apparatus above described a speed regulator,
and an indicator. The former comprises a disk 10 mounted on the motor shaft
or to a smaller disk on said shaft by means of diametrically opposite pivot
pins .o.
At its end the shaft Eis bored out to receive a bar Othat has a free movement
in the shaft in line with its axis. To the bar O¹ is secured an arm 0" that engages
with a 'lug on or enters a recess in the face of the. disk O. A spring plate P, the
portion of which is regulated by a set screw Pl, bears against the end of rod O

page_text: and tilts the disk O. Centrifugal force opposes this action of the spring P, and as
the disk tends to place itself at right angles to the shaft the rod O is forced
outward and the spring P bent back. This movement may be utilized in various
ways for regulating the motor, as by making and breaking the circuit that supplies
current to the motor, as I have illustrated in Fig. 8.
'
On the opposite end of the shaft E' is a similar disk R held in an angular position
by a spring p. This disk moves a sleeve R¹ longitudinally on an extension of the
shaft E' and determines the position of a bell-crank lever R" that carries a rack S
engaging with a pinion on the shaft of a pointer S¹. This latter sweeps over a
graduated dial plate, the divisions of which indicate the number of turns of the
shaft E per unit of time and hence the number of letters being sent or rate of
transmission.
The indicator is set or adjusted once for all, and shows at all times the work the
apparatus is doing. To increase or reduce the rate of transmission, therefore, it is
only necessary to adjust the screw P1 and by it the speed of the motor until the
indicator shows the machine to be doing the work desired.
Heretofore machines of this character have been provided with devices for
indicating the adjustment necessary for given rates of transmission, but the
accuracy of these devices presupposes perfect operative conditions in the machine.
The devices which I employ, however, indicate the work done by the machine
whether in order or not, and any variation from proper conditions is at once
shown.
It will be understood that the machine instead of operating the transmitting keys,
as herein described, could be used with such modifications as are well understood to
send impulses of current directly into a cable, but the plan described I consider
preferable.
Having now particularly described and ascertained the nature of my inven-
tion, and in what manner the same is to be performed as communicated to me by
my foreign correspondent I wish it understood that what I claim is,
1. In a telegraphic transmitting device the combination with the circuit-con-
trolling trailers, of an intermittently-fed perforated strip or tape, timed as to its
movements so that the perforations therein will lie under the trailers during its
periods of rest, as set forth.
2. In a telegraphic transmitter the combination with the circuit-controlling
trailers, of a tape-feeding mechanism capable of intermittent movement and a tape
engaged and fed thereby and having perforations therein at points which lie under
the trailers during the periods of rest of the feed mechanism, as set forth.
3. In a telegraphic transmitter the combination with the circuit-controlling
trailers, a strip or tape containing perforations, and a switch adapted to interrupt
the circuit completed by the trailers and during the period of engagement of either
of said trailers with a perforation in the tape, as set forth.
4. In a telegraphic transmitter the combination with circuit-controlling trailers,
of an automatic switch in the circuit of the trailers and adapted to interrupt the
circuit in advance of the trailers, as set forth.
5. In a telegraphic transmitter the combination with circuit-controlling trailers,
of a switch in circuit therewith, mechanism automatic in its action for operating
said switch to break contact in advance of the trailers, and means for varying or
adjusting the duration of contact, as set forth.
6. In a telegraphic transmitter the combination with the circuit-controlling
trailers, a perforated tape and a feed mechanism therefor capable of intermittent
movement and timed so that the engagement of the trailers with the perforations
continues during the periods of rest of the feed mechanism, of a switch in circuit
with the trailers and mechanism for causing the same to break contact during the
periods of rest of the tape-feeding mechanism, as set forth.
7. In a telegraph transmitter the combination with circuit-controlling devices or
trailers of a tape-carrier moved or adapted to be moved intermittently and a tape

page_text: provided with perforations or their equivalents, the movements of said carrier and
tape being timed with respect to the spacing of the perforations so that the said
perforations are encountered by or will lie under the trailers during their periods.
of rest, as set forth.
8. In a telegraphic transmitter, the combination with circuit-controlling trailers
of a power-driven shaft, a wheel receiving intermittent rotation therefrom, and
provided with pins at equidistant points on its periphery, a tape having a line of
equidistant perforations with which the pins engage and perforations in the line
of travel of the trailers, and spaced so as to be engaged or encountered by the
trailers during the periods of rest of the wheel.
9. The combination with the circuit-controlling trailers, a power-driven shaft
and a tape-carrying wheel moved step-by-step by the shaft, of a circuit-breaker or
switch in circuit with the trailers and a cam on the shaft for raising or moving the
switch off from its contact and interrupting the circuit during the periods of rest
of the tape-carrying wheel and in advance of the trailers, as set forth.
10. The combination with the circuit-controlling trailers, a power-driven shaft
and a tape-carrying device receiving an intermittent or step-by-step motion from
the same, a switch in the circuit with the trailers and a cam on the shaft for
raising or moving the switch, said cam having the edge that encounters the switch
straight and parallel with the axis of the shaft, and the other edge oblique thereto,
said cam and switch being adjustable with respect to each other in the direction of
the axis of the shaft.
11. In a telegraphic transmitter the combination with the transmitting devices.
of a motor imparting movement thereto, a regulator for adjusting the speed of the
motor and an indicator of the rate at which the motor is running, as set forth.
12. The combination of the motor and its shaft, the worm or cam F on the shaft,
the wheel F with peripheral pins or teeth engaging with the worm, the wheel G
with corresponding pins moving with the wheel F₁ a paper strip with perforations
which are engaged by the teeth of wheel G and the trailers a, b under which the
paper travels, as set forth.
13. The method of transmitting signals or electric impulses by means of circuit-
controlling trailers and a perforated tape which consists in moving the tape under
the trailers with its perforations in the lines of contact of the trailers and permitting
the tape to remain at rest for a given time during the periods of the engagement
of the trailers with the perforations therein.
14. The method of transmitting signals or electric impulses by circuit-controlling
trailers and a perforated tape which consists in moving the tape under the trailers
intermittently, permitting it to remain at rest for a given time during the periods
of the engagement of the trailers with the perforations therein, and interrupting
the circuit closed by the trailers by an independent circuit-breaker and in advance
of the action of the trailers, as set forth.
15. The method of transmitting signals or electric impulses by means of circuit-
controlling trailers and a perforated tape which consists in moving the tape under
the trailers so that they may pass through the tape and close the circuit whenever
a perforation iu the tape is encountered by them, and interrupting the circuit thus
closed by an independent or separate circuit-breaker, and in advance of the action
of the trailers or before they leave a perforation, as set forth.
Dad the 1st dor of M 1902
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.