Improvements in Autographic Telegraphs and Automatic Switches for the same.
Year: 1891

page_text: Date of Application, 3rd Feb., 1891-Accepted, 2nd May, 1891
[Communicated from abroad by THE WRITING TELEGRAPH COMPANY, of No. 45,
Murray Street, New York, United States of America.]
Improvements in Autographic Telegraphs and Automatic Switches
for the same.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Fellow of the Institute of Patent Agents, 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 relates to autographic telegraphs, and consists first in improvements
in the transmitter whereby greater certainty and reliability in the variations of
resistance, as well as quicker action, is secured, and oxidation of contacts prevented ;
and second in means for controlling the circuits between subscribers and a central
office in an autographic telegraph exchange system, whereby the switching will be
effected automatically, thus obviating the necessity for the manual adjustment of the
mechanism by the subscriber to make the required connections to throw the
transmitter or receiver into or out of circuit.
In carrying out this latter part of my invention the transmitting stylus is utilized
as a part of the switching means, and in the normal condition of the apparatus the
stylus automatically maintains such a relation to the other elements of the switching
means as to keep only the receiver in circuit, but when the stylus is moved from
its position of rest, when grasped by the hand of the operator to transmit a message,
the connections are automatically so changed as to cut in the transmitter, and when
the writing has been done and the operator releases the stylus it at once assumes its
normal position and thereby cuts the transmitter out of circuit.
In the accompanying drawings forming part of this Specification,
Fig. 1 is a perspective view of a part of my improved transmitter.
Fig. 2 is a side view of the same.
Fig. 3 is a plan view of Fig. 2.
Fig. 4 is a plan of the transmitter.
Fig. 5 is a diagrammatic view, and
Fig. 6 is a side view of the circuit maker and breaker.
Referring to the drawings (Figs. 1 to 4) 1 represents the top plate of the
transmitter, adapted to be held by an enclosing case, (not shown). A rod 2
depends from said top plate and supports the base 3. Secured to said base and
arranged at right angles to each other, as shown, are two receptacles or holders 4
in which two series of steel spring tongues 5, 5, 5b etc. are separately held in a
vertical position by an insulating cement 6. The spring tongues 5, etc. are placed
in line with each other, edge to edge, with a sufficient space between them to
avoid contact. They are hardened and tempered so as to readily return to
normal position after pressure thereon is released. To the lower ends of these
tongues a series of resistances 7, 7, 7, etc. are secured, as shown in Fig. 4 while
their upper ends are provided with platinum contacts 8. Secured in the insulating
cement of each holder are two spring strips 9 which carry a contact bar 10 of
brass, having its side next the spring tongues arranged at an angle thereto, as
shown in Figs. 3 and 4. These two contact bars are each provided with a
platinum strip or surface 11, placed opposite the platinum contacts of the spring
tongues and, by reason of their spring supports, can be brought into contact
with said tongues, each tongue making contact independently of the rest. A
stylus rod 12, screw threaded on its lower end, is screwed into the base 3, being
held tightly in position by a lock nut. Its spring part 13 allows free movement
of the upper end in any direction. A spring 14 is preferably employed to bring
the stylus back to normal position. Said stylus rod carries a pressure block 15

page_text: secured thereto by two set screws 16, the stylus rod passing through a hole in
said block. Two adjustable pressure heads 17 are screwed to the block and can
be held tightly by lock nuts 18 in whatever position they may have been
adjusted. The faces of these pressure heads are hardened and polished to secure
a free and easy action when said heads press against the projections 19 on the
contact bars. These projections are likewise hardened and preferably terminate
in a point so as to present the smallest possible surface to the pressure heads.
When the stylus is in its normal position the pressure heads are so adjusted
that contact is made with the projections 19 whereby any lost motion is prevented.
The pressure heads are uninsulated, as well as the pressure block, from the
stylus rod. When the stylus is operated the contact bar is pressed against the
tongues making contact with all or a lesser number according to the extent of
movement of the stylus, thus cutting in or out the resistances required to regulate the
movement of the receiving pen.
Heretofore, in autographic telegraph transmitters, the resistances have been
arranged in series. This arrangement is objectionable, for any break of circuit
at the points of contact means a break of the whole circuit and oxidation at the
contact points. To overcome this objection, I arrange the resistances as shown
in the drawings. I employ two series of resistances, 7, 7", 7" etc. and 20", 20", etc.
the former arranged in parallel arc, the latter in series, and I combine these
two in a manner to avoid an electrical break in the circuit. The objection to
the series system is to a considerable extent overcome by the resistances 7, 7", 7",
etc., arranged in parallel are, for as the current is distributed through several
branches, which are broken when the contacts are separated, the possibility of
oxidation at contact points is proportionately reduced. The objection to the series
system is, however, entirely overcome by combining with said resistances 7, 7", 7",
etc., another set of resistances arranged in series, independently considered, both
sets of resistances being connected to the tongues. The resistance 7", is of the
same resistance, measured in ohms as resistance 20". The resistance 7 is less
than 7, but is of the same resistance as 20", and so forth, the resistances continuing
to decrease, that is to say, the resistances are graded from a maximum resistance
arranged farthest from the receiver to a minimum resistance of practically zero.
The operation is as follows: When the tongues are all out of contact with the
contact bar the current circulates in every branch, of course, proportionately to
resistance. When through the movement of the stylus tongue 5 touches contact
bar 10 the resistance 7" placed in parallel arc with resistance 7 while the
resistance 20, of equal resistance with 7" is practically electrically cut out, the
amount of current still circulating in 20 being so extremely little as to be
practically disregarded. The resistance 20, therefore, prevents an open circuit
in 7 when 5 breaks contact with the contact bar, balancing the resistance 7" then
practically cut out, and so preventing an open circuit and consequent sparking.
In other words the resistance 20 offers another and equivalent passage for the
current the moment 7" is separated from 7. The resistance 20 stands in the same
relation to resistance 7" that 20 stands to 7 and so on throughout the remainder
of the arrangement of resistances.
Referring now to Fig. 5 of the drawings 19 indicates the transmitting stylus
grounded at 44 and arranged to pass through an opening in a frame secured to a
table (not shown). In said frame are arranged three insulated contact pieces 11, 12
and 13 all insulated from each other. These contacts are provided with platinum
surfaces, also the stylus, to ensure a satisfactory electrical contact. For the sake
of clearness in the drawing I have shown in Fig. 5 the transmitter sections shown in
United States Patent No. 353,593 granted James H. Robertson, dated Nov. 30, 1886,
but it will be readily seen that the transmitter sections shown in Figs. 1 to 4 can
be substituted therefor, the stylus being substantially the same in both. Referring
again to Fig. 5 which is designed to illustrate the utilization of my invention in an
autographic telegraph exchange system, 24 indicates the central office, and 25 and 26
two sets of apparatus for subscribers. The office batteries are indicated by 27 and 28

page_text: the battery plugs by 29 and 29' and the openings in the switch-board which receive the
battery plugs by 30 and 30'. The line 31 connects the central office switch board
with the magnet 32 of the receiving instrument, said magnet being also connected
by wire 33 with contact 11 of the individual switch mechanism. The transmitter
section for the receiver magnet 32 is indicated by 34 and it is connected by wire 35
to contact piece 11 and is grounded at 36. The transmitter section for the receiver
magnet 37, which latter is connected to contact piece 12, by wire 38, is indicated
by 39 and is connected to contact piece 12 by wire 40 and grounded at 36, as
shown. Line 41 connects the central office switch-board with contacts 42, sec
Fig. 6, at which point is located a circuit breaker and maker, the latter being
connected by wire 43 to receiver magnet 37. Any suitable construction of circuit
breaker and maker may be employed but I prefer to make use of that construction
shown in my United States Patent No. 435,292 dated Aug. 26, 1890, wherein an
arm carrying a pair of armatures is pivoted in such relation to electro-magnets
preferably the receiver magnets-and contacts corresponding to 42 as to be controlled
by said magnets, the circuit being completed by the depression of the pivoted arm
when the magnets are energized and broken by the elevation of said arm when the
current is switched off. The transmitting stylus besides being pivoted as usual in
the base plate of the transmitter is grounded as at 44. A spring 14 (see Fig. 1)
normally holds the stylus in contact with the contact points 11 and 12 (see Fig. 5),
so that when the stylus is released by the operator after a message has been
written, it automatically resumes its normal position with its contact resting against
contact points 11 and 12.
At the central office, 45 indicates the location of the annunciators, 46 battery,
and 47 annunciator magnets connected to the batteries 46 and grounded at 48.
Wire 49 is connected to the central office switch-board, and also to the line 41 as
shown. The line 41 where it is joined to the binding post 50 has an extension 51
which is connected to contact 13 as shown, and it is brought into play to effect the
dropping of the annunciator shutter at the central office when the stylus 19 is moved
over in contact with said contact piece 13, as presently explained.
From the above description of the construction of the mechanism, and the
disposition of its various elements, the following explanation of the circuits will be
readily understood.
In Fig. 5 of the drawings both sets of apparatus, 25 and 26, are in condition for
receiving, my switching instrumentalities automatically maintaining the receivers in
circuit. If the subscriber controlling apparatus 26 desires to call up the central
office he takes hold of his transmitting stylus 19, and moving it away from
contacts 11 and 12 brings it for a moment in contact with contact point 13 and then
permits it to resume its normal position in contact with points 11 and 12. The
momentary contact of stylus 19 with contact piece 13 causes the annunciator shutter
at the central office to drop, the circuit being completed through the stylus 19 to
effect that result as follows:-Beginning at ground 48, to which battery 46 is
connected, the circuit is through annunciator magnet 47 and wire 49, thence through
line 41 to binding post 50, and through wire 51 to contact piece 13 and to stylus 19
to ground 44. Upon receiving the signal communicated in manner just explained,
the central office attendant plugs in the subscriber calling (another office battery-
plug being in, or may be put in, the office connection to the office instrument) and
said subscriber is then enabled to communicate with the central office, the circuits
being as follows when thus communicating: From the ground of the central office
instrument and through said instrument and by line 31 to receiver magnet 32 which
when energized closes contacts at 42, from thence through wire 33 to contact piece!!
and through wire 35, transmitter-section 34 to ground 36: and from the ground of
the central office instrument and through said instrument and through line 41 to
receiver magnet 37: from thence through wire 38 to contact piece 12 and through
wire 40, transmitter-section 39 to ground 36. The central office attendant having
plugged in the called subscriber, the calling subscriber moves his stylus away from
contact with contact-pieces 11 and 12, in order to manipulate the same within the

page_text: :
square in forming the characters to be traced by the pen of the receiver, and in this
movement he cuts in his transmitter, the circuits then being from ground 36 (of
apparatus 26) to transmitter-section 34, through wire 35 to contact point 11, through
wire 33 to receiver magnet 32, through line 31 to battery plug 29 to upper
battery 28 from thence to battery-plug 29' through line 31 to the called subscriber's
apparatus (25) to receiver magnet 32 wire 33 to contact piece 11, to stylus 19 in
contact therewith and to ground 44. The second circuit starting from ground 36
of the calling subscriber's apparatus, passes to transmitter-section 39, by wire. 40 to
contact-point 12, from thence by wire 38 to receiver. magnet 37 and to binding
post 50 from thence through line 41 to outside contact of battery plug 29, through
lower battery 27 to outside contact of battery-plug 291: from thence through line 41
to binding post 50 of the called subscriber's apparatus (25) then to receiver magnet 37,
and by wire 38 to contact point 12 to stylus 19 and to ground 44. When the calling
subscriber has finished writing and releases his transmitting stylus, the moment it
assumes its normal position in contact with contact-points 11 and 12, his transmitter
is thrown out of circuit, his instrument being again in normal condition and in readiness
to receive a message.
It will thus be seen that to normally maintain the receiver
in circuit, and to bring the transmitter into circuit when it is desired to send a
message and to cut out the transmitter when the message has been sent, requires
no calculation or care on the part of the subscriber, the operations being wholly.
automatic.
In Fig. 4 the opening in the top plate 1 for the passage of the stylus rod is
provided with notches 23 and 24 in two of its four corners. Contact pieces 25
and 26 connected to receiver 30 by wires 40 and 41 are arranged in notch 23. and
contact piece 27 connected with line 42 to connect with a central office switch
board is arranged in notch 24. If the corners were not notched (as in Fig. 5) it
will occasionally happen if the operator is not very careful in handling the stylus
that the stylus rod will come accidentally into contact with the contact pieces and
thus disturb the operation of the instrument but by notching or cutting out the
corners of the square opening as shown in Figs. 1 and 4 I avoid this objection
and no matter how careless the operator is in moving his stylus about he cannot.
accidentally bring his stylus rod into contact with said contact pieces.
In Fig. 4, 31 represents a cross-section of the receiving stylus, 32 a part of the
paper feed releasing mechanism, and 33 the contact points closed by said mechanism,
34 the connection from transmitting stylus to ground, 35 and 36 the connections of
the transmitter resistances with ground and 37 and 38 the wires connecting receiver
to transmitter, but these features constitute no part of this invention being fully
described in my United States Patent hereinbefore referred to. I have arranged
the resistances of the transmitter so that the last tongue to make contact with the
contact bar controls the lowest resistance and this resistance is most directly
connected with the receiver.
In the position of the stylus rod shown in Fig. 4 the same makes contact with
contact pieces 25. and 26 and the circuits are then from the batteries A and B
through the magnets 30 of the receiver and by conductors 40 and 41 to contacts
25 and 26 to stylus rod 12 and thence to ground by conductor 34, the transmitter
being cut out. When the stylus rod is pulled over to make contact with contact
piece 27 the circuit is from battery A by conductor 42 to contact piece 27 to
stylus rod 12 and thence to ground by wire 34. When the stylus rod is being
operated to write it is, of course, out of contact with contact points 25, 26 and 27,
and the circuits are from batteries A and B through the magnets 30 of the
receiver and by conductors 37 and 38.through the resistances of the transmitter
in manner as previously hereinbefore explained and by wires 35 and 36 to ground.
Having now particularly described and ascertained the nature of my said in en-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. In an autographic telegraph, two series of contacts in which the contacts of

page_text: each series are separated from each other, two series of resistances cach graded
from a maximum to a minimum resistance and two movable contact bars each
arranged at an angle to its series of contacts, in combination with a stylus arranged
when operated to press against said contact bars, and press the latter against said
contacts, substantially as described.
2. In an autographic telegraph, two series of movable contacts in which the
contacts of each series are arranged in line with but separated from each other,
and are movable at right angles to said line, two series of resistances, each graded
from a maximum to a minimum resistance and two movable contact bars each
arranged at an angle to its series of contacts, in combination with a stylus arranged
when operated to press against said contact bars and press the latter against said
contacts, substantially as described.
3. In an autographic telegraph two series of flexible contacts, in which the
contacts of each series are separated from each other, and two movable contact
bars each carried by flexible supports and arranged at an angle to its series of
contacts, in combination with a stylus arranged when operated to press against
said contact bars and press the latter against said contacts, substantially as
described.
4. In an autographic telegraph transmitter a series of contacts connected to
flexible supports, insulated from each other and arranged in line with and movable
at right angles to said line, in combination with a laterally movable contact bar
arranged at an angle to said contacts and to press laterally against the same,.
substantially as described.
5. The combination with a transmitting stylus, provided with a pressure block,
of two contact bars carried by flexible supports and arranged to be moved by the
operation of said stylus, substantially as described.
6. The combination with a transmitting stylus of a pressure block secured
directly thereto and provided with a pressure head a movable contact bar provided
with a projection co-operating with said pressure head, and a series of electrically
separate contacts, substantially as described.
7. The combination with a transmitting stylus, a top plate provided with a
notched opening and contacts in said notch arranged to co-operate with the stylus
rod, of the stylus rod arranged to pass through said opening and a spring for
returning the stylus rod to its normal position in said notch, substantially as
described.
8. The combination with a transmitting stylus and a top plate provided with
a notched opening of contacts in said notch arranged to co-operate with the stylus
rod and a stylus rod arranged to pass through said opening and to be pressed
against said contacts in said notch, substantially as described.
9. In an autographic telegraph transmitter, the combination with two sets of
contacts and connecting means for electrically connecting the contacts of each set,
of two sets of resistances each set arranged to act in parallel arc, and a stylus
rod co-operating with said connecting means, substantially as described.
10. In an autographic telegraph transmitter the combination with two sets of
contacts and connecting means for electrically connecting the contacts, of two
sets of resistances cach set arranged to act in parallel arc, and two sets of resist-
ances each set arranged in series, substantially as described.
11: In an autographic telegraph transmitter two sets of resistances connected
to contacts and each set arranged to act in parallel arc, in combination with
two sets of resistances, each set arranged in series, substantially as described
12. In an autographic telegraph transmitter, the combination with two sets of
contacts of two sets of graded resistances, each set arranged to act in parallel
arc, and graded from a maximum to a minimum resistance substantially as
described.
13. In an autographic telegraph transmitter, the combination with two sets of
contacts, of two sets of graded resistances, each set arranged to act in parallel

page_text: arc, and two sets of graded resistances, each set arranged in series, substantially
as described.
14. In an autographic telegraph, the combination with the receiver and
transmitter of two sets of contacts and two sets of graded resistances, each set
arranged to act in parallel are the lowest resistance of each set arranged nearest
the receiver substantially as described.
15. The combination with the transmitting stylus provided with an uninsulated
pressure block and a contact bar co-operating therewith, of a set of contacts and
à set of graded resistances arranged with the lowest resistance next to the
receiver, said contact bar arranged to make contact with the contact of least
resistance last, substantially as described.
16. In an autographic or writing telegraph the combination with a transmitting
stylus electrically connected to ground of contact points electrically connected to
the line and shifting means arranged to automatically move and press said stylus
against said contact points substantially as described.
17. In a writing telegraph the combination with a transmitting stylus electrically
connected to ground, of contact points electrically connected to the line, and a
spring arranged to automatically press said stylus against said contact points
substantially as described.
18. In a writing telegraph the combination with a transmitting stylus electrically
connected to ground, of contact points electrically connected with the receiving
and transmitting instruments, and a spring arranged to automatically press said
stylus against said contact points, substantially as described.
19. In a writing telegraph the combination with a transmitting stylus electrically
connected to ground, of a contact point connected by a line to a central office
annunciator, said stylus being arranged in proximity to said contact point so that
it can be brought into contact with the same to close the circuit through the
annunciator to drop the shutter substantially as described.
20. In a writing telegraph the combination with a transmitting stylus electrically
connected to ground of two contact points each connected to both receiver and
transmitter and shifting means arranged to automatically move and press said stylus
against said contact points, substantially as described.
21. In a writing telegraph the combination with a transmitting stylus electrically
connected to ground of contact points clectrically connected to receiver and trans-
mitter said receiver being connected to transmitter and through transmitter to
ground, and shifting means arranged to automatically move and press said stylus
against said contact points, substantially as described.
22. In a writing telegraph, the combination with a transmitter and a receiver
of contact points in communication with said receiver, an independent contact
point in communication with the main line, and a grounded stylus normally resting
against the contact points communicating with the receiver-thereby normally
maintaining the apparatus in condition to receive a message and arranged to be
moved against said independent contact point to momentarily close the circuit
through the central office annunciator-magnet, substantially as described.
2001
ABEL & IMRAY,
Agents for the Applicant.