Improvements in and relating to Telegraphic Transmitting and Receiving Apparatus.
Year: 1894

page_text: Date of Application, 11th Dec., 1894
Complete Specification Lef:, 12th Aug., 1895-Accepted, 2nd Nov., 1395
PROVISIONAL SPECIFICATION:
3
Improvements in and relating to Telegraphic Transmitting and
Receiving Apparatus.
I, BERNHARD HOFFMANN of 16 Rue Monthyon, Paris, France, Contractor
for Public Works, do hereby declare the nature of this invention to be as
follows:-
-
My invention relates to telegraphic transmitting and receiving apparatus and has
reference more especially to the particular construction and arrangement of the
transmitter and receiver to the transmission of messages to a distance and to the
reproduction of such messages in the form of letters or characters at the receiving
station or at both the transmitting and receiving stations.
My invention comprises an instrument which may appropriately be called a
telewriter and is so arranged as to be used either as a transmitter or as a receiver;.
also the mode of escapement and the arrangement of electro magnets, armatures
and batteries and method of procuring an impression on a tape or band; also the
combination of the receiver and transmitter with a typewriter all as hereinafter
set forth.
While my invention can easily be varied in details of execution especially in point
of form, material and dimensions of the essential parts 1 will proceed to describe
one way of carrying the same into effect :-
On one spindle there may be mounted the following parts.
(a) A type wheel having engraved on its periphery the letters of the alphabet,
figures and such other characters as may be desired.
(b) A ratchet wheel.
(c) The last wheel of a clock movement.
(d) An arm carrying at its outer extremity a brush capable of rubbing or coming
into contact with successively a series of divisions on a dial hereinafter referred to
as the principal divisions.
This arm also carries a second brush which is insulated from the arm and so
arranged that it brings into communication two supplementary divisions.
The principal divisions which may for example be 48 in number are insulated
from one another and are so arranged that every division is connected with one of
the keys on the key board. The number of divisions may be more or less so long
as they are even in number.
These keys are alternately earthed by means of suitable contacts and insulated.
By pressing on the keys in communication with earth they are insulated; on
pressing on the insulated keys they are earthed by means of other suitable
contacts.
The key communicating with the principal divisions opposite the supplemental
divisions should always be in communication with earth in its normal position.
The ratchet wheel carries an anchor escapement movement, the escapement being
furnished with a pin or projection which forms an armature suitable to the electro
inagnet of a relay hereinafter referred to as electro magnet No. 1.
The escapement 'wheel can be mounted on a suitable spindle communicating with

page_text: the first by suitable mechanism in order to obtain for each tooth of the escapement
wheel the advance of a principal division of the dial.
If the electro magnet No. 1 be traversed successively by currents in different
directions the armature oscillates between the poles and the escapement moves
forward one tooth at each change of the current. The brush therefore turns and
comes into communication with each of the principal divisions successively.
Another relay the electro magnet of which hereinafter referred to as No. 2
and having a polarizable armature is introduced in order to send through electro
magnet No. 1 a series of currents in the opposite direction.
In order to effect this a battery which I will call No. 1 is connected from its
centre to the armature of electro magnet No. 2; in the circuit is interposed the
electro magnet No. 1 as also another electro maguet No. 3 whose-armature carries
a roller. A tape-or-band of paper or other suitable material passes between this
roller and the type wheel. When the electro magnet No. 3 attracts its armature
the roller causes the tape to be applied against the type wheel and consequently
.causes the impression of the letter which is opposite. The two extremities of
battery No. 1 are connected with two contacts; between which oscillates the
armature in connection with electro magnet No. 2.
If a current is made to traverse the electro magnet No. 2 and then broken the
armature causes the circuit to be closed first on one contact and then on another
and thus there is sent through electro magnet No. 1 a series of currents first in one
direction, then in another.
A commutator should be provided for the purpose of making the apparatus a
receiving machine or a transmitting machine.
Supposing the machine to be in the position for transmitting that is to say when
a lever of the commutator is (say) lowered and supposing further that the brush on
a principal division communicates with the earth by means of one of the odd keys
the circuit of a second battery hereinafter called battery No. 2 is closed by the
earth, the brush, the brush arm, the battery No. 2 the plates of the commutator,
the electro magnet No. and the line wire.
In the position for receiving (that is where the lever is raised) the current
arrives by the wire and goes to earth by the electro magnet No. 2 which is
connected to earth by means of the plates of the commutator.
In each machine then (that is to say the machine at the transmitting end and
the machine at the receiving end) the armature of the electro magnet No. 2 is
attracted; the armature closing the local circuit thereby causing the armature of
electro magnet No. 1 to be attracted by one of its poles; the escapement therefore
moves one tooth. At the same time the brush arm moves one division on the dial.
At the transmitting machine the following division being insulated' the armature
'of the electro magnet No. 2 is drawn back by a suitably placed spring, the circuit
closes by the other contact the armature of electro magnet No. 1 is attracted by
the other pole and the escapement of each machine again moves one tooth.
There is thus obtained a synchronous movement of the two brush arms and
consequently a synchronous movement of the type wheel. Supposing now that the
brush leaving a division in communication with the earth, comes upon a division
which instead of being insulated is likewise in communication with the earth or
the reverse, the armature of the electro magnet No. 2 remains attracted,
consequently the escapement does not move a tooth and the whole arrangement
stops.
At this moment the electro magnet No. 3 attracts its armature and a letter is
therefore impressed upon the tape. This armature does not act during the rapid
changes of the current not having the time to respond to the attraction on account
of the weight of the armature being heavy.
This is what happens when the operator presses on a key. The division of the
dial, if it be insulated, is earthed; if on the other hand it is in communication with
the earth it is insulated and the letter corresponding to the key and a division is
impressed upon the tape at each of the two machines.
FI "

page_text: If it be desired to avoid making an impression at the transmitting office the
electro magnet No. 3 should be short, circuited by means of a suitable additional
commutator. The advance of the tape after each impression is effected by means
of a feed apparatus operated by an electro magnet which is itself brought into
action by the movement of the keys.
The arrangement of the first commutator has been referred to. By means of
this arrangement the current traverses the electro magnet No. 2 always in the
same direction whether the machine is used as a receiver or transmitter. This
direction I term the normal direction of the current.
A special arrangement allows synchronism to be established at any moment.
For this purpose the second brush on the arm puts into communication at a point
of the circumference of the dial corresponding to a predetermined letter the two
supplemental divisions which close through electro magnet No. 4 the circuit of a
local battery the armature of the electro magnet No. 2 being thus polarized. At
the same moment the electro magnet No. 2 is traversed by a current by virtue
of a division in connection with the earth. If the current which traverses the
electro magnet No. 2 is of the normal direction the polarizations of the electro
magnets Nos. 2 and 4 are of contrary direction and the armature being attracted
the advance of the escapement takes place as usual. If the current is not of the
normal direction, which is caused by changing the direction by means of a button
or plug the two polarizations are of the same character the armature is not attracted
and the position is the same as if two consecutive divisions were of the same
character and everything stops.
If then two machines are in communication the operator of the transmitting
machine commences by pressing down the commutator lever and the two machines
are put into operation.
The operator presses on the button or plug and sends a current (contrary to the
normal current) through the two apparatus. Supposing that the receiving machine
is in advance of the transmitting machine, the machines work until at the receiving
machine the second brush comes on to the supplementary divisions. At this
moment the receiving instrument stops, the transmitting instrument proceeds until
its second brush comes equally in contact with its supplementary divisions when
it is only necessary to let go a suitable stop and the two machines work
synchronously.
If on the contrary the transmitting machine is in advance of the receiving
machine the two machines will be stopped when at the transmitting machine, the
second brush has been put into communication with the supplementary divisions
since it is this machine which should produce the current and the break in the
current. The plug should be raised an instant, then let go, the machines will
have advanced one tooth, and will again commence to work but the transmitting
machine will be behind the receiving machine.
Before then commencing to transinit a message the operator at the transmitting
machine has to press twice on the plug thus forcibly establishing synchronism,
He has then only to manipulate the keys on the key board in order to impress as
required by the machine at the receiving station only or by the machines at both
the receiving and the transmitting stations.
A second type wheel may be mounted on the same spindle as the first and be
brought into operation when required by moving the tape laterally; this can be
effected by means of an electro magnet which acts when a special key is
depressed.
Dated this 11th day of December 1894.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Patent Agents.

page_text: Improvements in and relating to Telegraphic Transmitting and
Receiving Apparatus.
I, BERNHARD HOFFMANN of 16 Rue Monthyon, Paris France, Contractor for
Public Works, 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:-
This invention relates to telegraphic transmitting and receiving apparatus and its
special object is to transmit messages to a distance and reproduce them in the form
of letters or characters at the receiving station or at both the transmitting and
receiving stations upon continuous bands of paper the operating machine being
analogous to the keyboard of an ordinary typewriting machine. The two stations
that is to say the receiving station and the transmitting station are connected by a
line wire in the same way as ordinary telegraph instruments.
It is sufficient to press at the transmitting station on one of the keys of the key-
board in order to obtain at the receiving station alone or at both the receiving and
transmitting stations a reproduction of the corresponding letter on a band of paper
which automatically unrolls as the successive impressions of the various characters
which the keys of the operating keyboard present are effected.
By the aid of this apparatus it is easy for a person to transmit a message to u
distance without previous experience.
The apparatus comprises a keyboard mounted on a box enclosing the receiving
mechanism and also comprises a call bell and a series of contact keys, accessories
for the purpose (as in electric telegraphy) of putting the apparatus in circuit and
arranging it for transmission or for the reception of a message.
Figure 1 of the annexed drawings represents diagrammatically the grouping of
the various parts of the apparatus.
Figure 2 is a transverse section of the stand which carries the keys and accessory
buttons for the call; for making the circuit, or for ringing up and for breaking the
circuit as hereinafter fully explained.
Figures 3 and 4 are respectively a front view and a side elevation of the complete
apparatus.
Figure 5 is a longitudinal section of part of the keyboard.
Figure 6 is a front view, Figure 7 a plan Figure 8 a back view and Fig. 10 a
transverse section of the receiver on a larger scale.
Figure 9 shows the clock movement and the mechanism for unrolling
the paper.
Figure 11 shews in front view the dial E hereinafter described with its series of
metallic divisions and the brush-carrying arın D.
Figure 12 shews the arrangement of the contacts to lead the current to the
electro-magnet which regulates the advance of the band of paper.
On one spindle are mounted the following parts:-
(1) A type wheel A having engraved on its periphery the letters of the alphabet,
figures and other such characters.
(2) An escapement wheel B.
(3) The last wheel C of a clock movement.
(4) An arm D carrying at its extremity a brush a capable of rubbing or coming
into contact successively with a series of metallic divisions b', 63, 63... 6 arranged
in a circle on an insulating dial E. The arm D also carries a pair of brushes cc
connected together but insulated from the arm D and so arranged as to bring into
communication two supplementary divisious de on the same radius as the first
division (Figures 1, 10 and 11).

page_text: The divisions 6' &c. ought to be of even number (there are 48 in the drawings); i
they are insulated from one another and every division is connected with a separate
key of the keyboard.
These keys are alternately earthed by the contacts t¹, t, t,.. and insulated.
By pressing on the keys in cominunication with the earth, they are insulated; by
pressing on the keys which are insulated when not acted upon they are earthed by
means of the contacts t³, t, t . . . £48.
The key communicating with 6¹ the position of which corresponds with d and e
ought always to be in communication with the earth in its normal state.
The wheel B carries (see Figures 1 and 8) a wing escapement mounted on the
spindle B' which is furnished with a polarized armature oscillating between the
two poles of the electro magnet G.
If the electro-magnet G be traversed successively by currents in different
directions the armature F oscillates between the poles and the escapement wheel
moves forward one tooth at each change of the current. The brush a then turns
and comes successively into communication with each of the divisions b', b², 63 &c.
H (Figures and 8) is a relay with polarizable armaturef for sending through
the electro-maguet G a series of currents of opposite direction. For this purpose
a battery is connected from its centre to the armature ; in the circuit is
interposed the electro-magnet G as also a secoud electro-maguet K whose armature
carries a roller g (Figures 1, 6 and 8). A tape or band of paper passes between g
and the type wheel A. When the electro magnet K attracts its armature the
roller y causes the tape to be applied against the type wheel A and consequently
causes the impression of the letter which is opposite. The two extremities of the
battery are connected with the two contacts I'm.
If a current is made to traverse the electro magnet H and then broken, the
armature causes the circuit to be closed alternately through and m and thus there
is sent through the electro magnet G a series of currents, first in one direction, then
in another.
I will deal in the first place with the transmitting station. In order to put the
apparatus as shown in Figure 1 into position to act as a transmitting instrument
I press down the keys of the commutators Y and S. By the pressing down of the
key of the commutator Y the spring plate which was previously pushed outwards
by the part Y* of the commutator and was connected with the bell circuit as seen
in Figure 1, is freed from the part Y* (because this is now lowered) moves inwards
and thereby makes contact with the plate. By the pressing down of the key of
the commutator S the spring plate e, which was previously pushed outwards by the
part S* of the commutator and was connected with the circuit of the electro
magnet H as seen in Figure 1, is freed from the part S* (because this is now
lowered) moves inwards and thereby makes contact with the plate d; at the same
time the spring plate n which was also previously pushed outwards by the part S*
and was connected with earth as seen in Figure 1, is similarly freed, moves inwards
and thereby makes contact with the plate t while the plate u' comes into electrical
circuit with the plate v¹.
Suppose now that the brush a is placed on one of the divisions of the dial, 67 for
example; this division being in connection with the earth the current will then
follow the course about to be indicated.
It passes by T, the key of the keyboard, the division of the dial, the
brush a the arm D, the connecting wire a' c d e f g h¹¹, the plates o' and n³ of
the commutator X, the wire j' ', the battery Z, the wire m' no', the plates p¹
and q of the commutator X, the wire 's', the plates t' and n of commutator S,
then the plates of this commutator so as to go by cly to the electro
magnet H, then by a² ²² to the wire f' and then to the plates gh' of the
commutator N, thence by, the plates of the commutator Y, then by wire m³
to the plates n² and ot of the commutator N, and thence to the line wire p³.
Dealing now with the receiving station, at this station the key of the commutator Y
is alone pressed down and the course of the current is as follows: The current

page_text: arrives by the line wire and travels through the plates o' and n' of the
commutator N, the wire m², the plates k² 12 of the commutator Y, the plates ³
and 2 of the commutator N', the wire the plates e and p² of the commutator S,
then proceeds to the electro magnet H by y' z' and returns by a³ ³ the plate n³,
then no and the earth.
In each station the armature f of the electro magnet His attracted (Figure 8);
coming in contact with m closes the local circuit and the armature F of the electro
magnet G is attracted by one of its poles; the wheel B moves one tooth. At the
same time the brush a moves one division on the dial; at the transmitting station
the following division being insulated the armature f is drawn back by the spring p
the circuit is closed by fand 1, F is attracted by the other pole of the electro
magnet G and the wheel B again moves one tooth at each station.
There is thus obtained a synchronous movement of the arms D at each of the
stations and consequently of the type wheels A. Supposing now that the brush a
leaving a division-in-communication with the earth comes upon a division which
instead of being insulated is likewise in communication with the earth (or the
reverse) the armature of the electro-magnet H remains attracted, consequently
the wheel B does not move a tooth and the whole arrangement stops.
At this moment the electro-magnet K attracts its armature and a letter is
therefore impressed upon the tape. This armature does not act during the rapii
changes of the current not having the time to respond to the attraction on account
of the weight of the armature being heavy.
This is what happens when the operator presses upon a key (Figures 1 and 5).
The division of the dial, if it be insulated is earthed; if on the other hand it is in
communication with the earth it is insulated and the letter corresponding to the
key and to the division is impressed upon the tape at each of the two stations.
If it be desired to avoid making an impression at the transmitting station the
electro magnet K should be short circuited by means of the commutator N. The
advance of the tape takes place after each impression by means of the electro-
magnet P (Figures 1 and 9) brought into the circuit of the battery R by the
armature of the electro-magnet K when the latter works (Figures 1 and 12).
It is necessary to notice the arrangement of the commutator S Figure 1. By its
arrangement the current always traverses the electro-magnet H in the same
direction whether the machine is used as a receiver or as a transmitter. This
direction I term the normal direction of the current. The commutator being in the
position represented, the apparatus is ready to act as a receiver; when the key is
pressed down it modifies the ccunections and the apparatus is arranged for
transmission.
A special arrangement allows synchronism to be established at any moment.
For this purpose the double brush c c (Figures 1 and 10) puts into communication
at a point of the circumference of the insulated dial E, the two supplemental
divisions de which close through the electro-magnet T (Figures 1 and 8) the
circuit of the local battery U the armature f of the electro-magnet H being thus
polarized. At the same moment the electro-magnet H is traversed by a current by
virtue of the division &¹ in connection with the earth. If the current which traverses
the electro-magnet H is of the normal direction the polarization of the electro-
magnets H and T are of contrary direction and the armature being attracted the
advance of the escapement wheel takes place as usual. If the current is not of the
normal direction which is caused by changing the direction by means of the button
or plug X the two polarizations are of the same character, the armature is no
longer attracted and the position is the same as if two consecutive divisions were of
the same character, that is to say everything stops.
If then the two stations are in communication the operator at the transmitting
station commences by pressing down the key S and the two machines are put into
operation.
The button X is then pressed down and a current (contrary to the normal
direction) is thus sent through the two machines. Supposing that the receiving

page_text: C
station is in advance of the transmitting station the two machines work until at the
receiving station ce¹ comes into contact with the supplementary divisions d e. At
this moment the receiving instrument stops, the transmitting instrument proceeds
until its brushes e c' come likewise in contact with its supplementary divisions de;
it is then only necessary to free the button X and the two machines work
synchronously. If on the contrary the transmitting station is in advance of the
receiving station the two machines will be stopped when, at the transmitting station
the brushes cc' come in contact with de since it is this machine which produces
the transmissions and breaks off current. The button X should be raised an instant,
then let go immediately; the machines will have advanced one tooth and will again
commence to work but the transmitting machine will be behind the receiving
machine; we are therefore brought back to the position stated in the first case.
Before then commencing to transmit a message it is necessary to press twice on
the button X thus forcibly establishing synchronism.
The spring of the armature is so adjusted that the armaturef is not attracted if
at the moment in which this armature is polarized, the electro-magnet H is not
traversed by any current (which is the case when the key corresponding to ¹ is
pressed down).
The battery Z is that which is in connection with the keyboard through the
intermediation of the divisions 61, 62, 63 &c.
A key N' is arranged so as to be able to stop the working of the apparatus and a.
call button N is arranged to cause the bell at the receiving station to be rung.
In cases where it may be necessary to print a text containing capitals or particular
signs the type wheel A is double; it can slide on its axis so as to present one or
other series of characters to the paper which the wheel g leads to it. This movement.
is regulated by a special electro-magnet W which receives the current by a special
key M. In this case a supplementary line is needed. If one wishes to make use
of the second part of the type wheel it is sufficient to press down the key W' which
introduces the electro magnet W into the circuit of the battery W'.
For facility of working there should be a supplementary key M' (Figure 3) both.
at the right and left of the last row of keys of the keyboard.
In practice the polarizable armature fis mounted with a hinge on the core of its
electro-magnet (Figure 8) placed by the side of the electro-magnet; it oscillates
between the two contacts and m which send the current of the battery J through
the coil of the electro magnet B.
The inking is effected by the wheel. The current is conducted to the brush a
by a rubber r insulated.
The double type wheel is displaced at will by two cams & which push it forward
under the action of the small connecting piece t Figure 10 lowered by the rod t¹ in
connection with the lever t* which is actuated by the armature of the electro.
magnet W. A spring wound on the spindle of the type wheel A tends constantly
to bring back this wheel when one of the supplementary keys M' is not pressed
upon. The paper which is unrolled from a reel above the receiver is led by the
guide rollers to the draw off roller controlled by the electro-magnet P.
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 a machine for reproducing letters or characters at a distance the combination
of the type wheel (A) an escapement controlled by an electro-magnet (G) having
a polarized armature (F) and a brush (a) rubbing on a series of fixed contacts
insulated from one another and arranged in a circle, all the above being mounted on
the same spindle worked by a clock movement; the escapement ceasing to work and
stopping the mechanism when the transmitter sends two currents in succession or
when it produces two breaks in succession through a relay magnet H which then
sends into the electro-magnet of the escapement two currents in succession of the.

page_text: same kind, direct or inverse, which stop the oscillation of the armature (F) which
carries the escapement, substantially as hereinbefore described.
2. In a machine for reproducing letters or characters at a distance the combination
of the special key X allowing the effect of the polarization of the armature of the
electro-magnet of the escapement G to be inactive in the case of the passage of the
current in the normal direction through the relay magnet H and effecting
the stoppage of the apparatus in the case of the passage of the current in the
opposite direction through the same electro-magnet, with the object of producing
synchronous working of the transmitter and the receiver substantially as hereinbefore
described.
1
3. In a machine for reproducing letters or characters-at a distance the-arrange-
ment of the armature carrying the roller g which leads the paper under the type
wheel A with a sufficient weight so that it is not influenced by the interrupted
currents which traverse the coil of its electro magnet K this armature being
attracted when the duration of the current is sufficient, substantially as hereinbefore
described.
4. In a machine for reproducing letters or characters at a distance the arrange-
ment of a double wheel with two series of characters engraved on its periphery,
this wheel being capable of receiving a movement longitudinally in the direction of
its axis to bring one or other of the series of characters opposite the band of paper
by means of a special electro-magnet W the armature of which actuates a
combination of levers and cams in order to displace the type wheel this latter being
brought back to its original position by a spring when the special electro magnet
ceases to act, substantially as herein before described.
Dated this 12th day of August 1895.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.