US2181989A - Communication system - Google Patents

Description

Cv R. DOTY Dec. 5, 1939.

COMMUNICATION SYSTEM Filed Feb. 12, 1938 3 Sheets-Sheet l ATTORNEY Dec. 5, 1939. c. R. DOTY 2,131,939

COMMUNICATION SYSTEM Filed Feb. 12, 1938 3 Sheets-Sheet 2 NVE TOR 25% BY V ATTORNEY & Ef e:

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E G1 I n 5 n Dec. 5, 1939. c. R. DOTY 2,181,989

COMMUNICATION SYSTEM Filed Feb. 12, 19:58 s Sheets-Sheet 3 ATTORNEY FIGS.

Patented Dec. 5, 1939 PATENT OFFICE 2,181,989 COMMUNICATION SYSTEM Charles R. Doty, Binghamton, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application February m, 1938, Serial No'. 190,246

7 Claims.

This invention relates to communication systems and more particularly to synchronously operated systems, one well known type of which is the printing telegraph system.

One of the objects of the present invention resides in the provision of a synchronous system in which a predetermined number of impulses, namely three, is employed to represent all characters to be transmitted and received.

Another object of the present invention resides in the provision of a synchronous system in which different characteristics are imparted to the impulses, thereby increasing the number of character permutations and effecting the selection of a single circuit for each permutation for a plurality of selection circuits at the receiver.

Another object of the invention resides in the provision of control means at the receiver which is conditioned by the first of a plurality of impulses representing a character to control selection means, the latter in turn being partially conditioned by the second impulse and completed by the third impulse ata differential time in the cycle, to effect the completion of a single character selection circuit.

Still another object resides in the provision of a synchronous system in which control members are used to initiate impulses at the transmitter, a predetermined number of these, namely three, being operated for each character to be transmitted, and a common control member being operated simultaneously, regardless of the character to be transmitted, to initiate a control impulse to effect the engagement of the normally latched members of a rotary distributing means with its synchronously driven members so as to condition a predetermined number of control circuits for transmitting the character impulses.

Various other objects and advantages of the invention will become obvious from the following description of one form of mechanism embodying the invention or from an inspection of the ac companying drawings; and the invention also constitutes certain new and useful features of construction and combination of par-ts hereinafter set forth and claimed.

In the drawings:

Fig. 1 shows, in part one type of transmitting and receiving control unit. 1

Fig. 2 is a detail perspective of an operating mechanism of the imit shown in Fig. 1.

Fig. 3 shows a rotary distributor means with one type of clutching arrangement which may be employed at the transmitter.

Fig. 4 is a circuit diagram for the transmitting station.

Fig. 5 is a circuit diagram for the receiving station.

For illustrative purposes, this invention is shown as embodying a well known type of recording unit, which may be similar in construction to the Electromatic typewriter, shown and described'in detail in U. S. Patent No. 1,777,055, and hence requires only the following brief descripion. a

I Referring to the drawings and particularly to Fig. 1, well known means are provided for actuating the type bars l6, comprising a constantly rotating roller Hi, cooperating with a series of individual poweru'nits each comprising a cam II, the engagement of the cams being controlled selectively by the character key bars l1.

Any suitable means may be provided to rotate the power roller, in the direction indicated by the arrow, which is adapted to cooperate with two rows of cam units arranged in the front and rear of the roller. Thecam ll may be provided to be pivoted on one arm of a bell crank lever l2 which is pivoted in the frame of the recording unit, as indicated generally by reference character i3, the other arm of the said bell crank lever being operatively connected with an arm of bell crank lever M by means of link l5. Another arm of said lever I4 is connected to the type bars IS in a well known manner, so as to effect operation of the type bars or any other suitable means connected to the bell crank levers-upon selective operation of the controlling key bars H.

The pivoted bell crank lever I2 is operated by r the associated cam H whenever the latter engages the driven roller; the engagement of the cam with the roller is controlled by means of the associated control key bar I! in a manner which will now be briefly described.

Referring now to Fig. 2, the cams occupy normally the positions as shown in this figure, which represents one of the rear bank of units. In this position the impeller-arm I8 is urged, by the associated coil spring it, against one of the impeller lugs 20, which at the time is in the lower position, and tends to turn the cam I l in a clockwise direction. This is prevented, however, by the engagement of one of the detents 2| on the cam, with the upper stop leg 22 on stop lever 23. If, however, the corresponding key bar is operated, the bifurcated lower end (Fig. 1) of extension arm 24 associated with one of the said key bars l1 engages an arm 25 at the upper end of the stop lever 23 which extends laterally through an opening in the bell crank lever l2. The arm 25 of the stop lever 23 is then swung rearwardly or to the left as viewed in Fig. 1 about the pivot 26 and its lower end forwardly or to the right as viewed in this figure, thus releasing the cam, which then turns under the influence of the spring urged impeller-arm l8. In doing so the upper serrated lobe of the cam is brought into engagement with the power roller which turns in a counterclockwise direction and therefore causes a continued rolling movement of the cam other mechanism with which the cam unit may be connected.

After the high point of the cam is passed the cam loses contact with the roller, but the said impeller-arm it tends to continue the rotation thereof by engaging the second impeller-lug 29 of cam ll until the second detent 21 engages one of the stop lugs. Since the half rotation of the cam consumes only a small fraction of a second, it is 'difiicult to release the key bar within this short interval, so that it is the lower lug 28 which is first engaged, but upon the release of the key bar and the return of the stop lever 23 to normal position, this lug 28 disengages the detent, whereupon the impeller-arm rotates the cam slightly, and the said detent then engages the upper stop lug 22.

It is obvious then that depression of a key bar ,releases the revolubly mounted cam to engage,

and be actuated by the power roller in turn operating the associated bell crank lever and its attached links to cause the associated mechanism such as the type bars and other operating mechanisms, to be operated. It is to be understood that an individual camunit is provided for each type bar or other functional mechanisms associated therewith.

The action of the cam mechanism has been described with respect to one of the rear bank of cam units; in the case of those of the forward bank the operation is analogous, but the (11160. tion of movement, and the order of operation of the stop lugs, is reversed. For example, if the bifurcated arm Ma is positioned to engage the arm 25a at the upper end of stop lever 23w by virtue of operation of the associated key bar, thesaid arm is positioned rearwardly or to the left as viewed in Fig. 1, and the lower end of the. stop lever 23a is moved forwardly, that is, to the right as viewed in said figure. This said operation is efiective to release the cam, by virtue of positioning the lower stop lug 2811. out of the path of detent Zia, thus permitting the spring urged impeller arm ita to rotate the cam slightly in a clockwise direction to effect engagement of the lower lobe' of cam H and the power roller. Upon completion of a half revolution of the cam H, the second detent 21a engages first, in the upper stop lug 22a while the stop lever 23a is in an operated position, but upon'release of the associated key bar and the return of the said stop lever to normal position, this lug 22a. disengages the said detent and the impeller-arm rotates the cam slightly so that the said detent then engages the lower stop-lug 28a, as shown in the figure. In ,this manner the bell crank lever i211 is rotated about the pivot l3a to operate the associated type bar or any other mechanism associated therewith. For further structural details of the cam units, reference should be made to the above mentioned patent.

When the mechanism described above is used as a transmitter, the cam II, when released, is arranged to operate a plurality of control members such as the contacts generally designated 10. An assembly of these contacts is located in the path of each of the cams, so that the depression of any key bar i? will result not only in the actuation of a type bar IE but also in the closing of a corresponding contact assembly for a very brief interval of time. The closing of these conual depression of the key bar l7.

tacts effect the initiation of impulses to represent the character to,be transmitted. I

, When the mechanism described above is used as a receiver, asolenoid 30 is associated with each key bar H so that upon energization of the solenoid the key bar will be drawn down and causethe corresponding type bar It to be actuated for the purpose of recording the character received. Obviously, the operation of the mechanism resulting from the energization of the solenoid 30 will be the same as thatresulting from the man- In the present system, rotary distributor units are located at the'transmitting and receiving stations and are vdriven in synchronism by synchronous motors or other suitable means well known in the art. One type of rotary distributor unit, generally designated 40 (Fig. 3), is shown to comprise two commutators and two control rings each having brushes associated therewith. The commutators, designated il and 42, are identical in every respect and are electrically insulated from 'each other by any suitable means. Commutator brushes 43 and 44 are mounted on an arm 45 and are insulated from each other and the arm by insulating material such as 46. The brush arm 15 is fixed to a constantly rotating shaft 41 which is driven by a synchronous motor (not shown). Thus the commutator brushes are caused to rotate continuously around the peripheries of the commutators ll and t2 and engage successively the individual conductive segments di-I to 6 and it-4 to 6 respectively in a mannerv well known in the art.

The control rings, designated 48 and as, are also electrically insulated from each other and are provided with insulating segments 50 and 5! respectively, the purpose of which will be described later in connection with the electrical circuits of the system. Two pairs of insulated brushes 52 and 53 are mounted on a brush arm 54 and are associated with controlrings 48 and 49 respectively. The brush arm 56 is associated with a clutching arrangement, and is thereby held in a latched position except when the clutch coil 55 is energized by a control impulse automatically sent to it simultaneously with the initiation of character impulses to be transmitted. This feature will be explained in detail later in connection with the electrical circuit diagram of the transmitting station. Upon momentary energization of the clutch coil 55 an arm 56 is displaced to the left and allows a dog 51 to be released and, under the impetus of spring 58, the dog will bear on the surface of a clutch member 59 pinned to the continually running shaft 41 until a predetermined time, near the end of the rotary distributor cycle in which the clutch coil was energized, when the dog 5'! will engage in a single tooth 60 of the clutch member. Once engaged with the clutch member, the dog will remain engaged and drive its connected mechanism through one cycle of operation, at end of which it will latch up on latching point 6! of arm 56. The dog 51 is connected by means of a collar .62 to the control ring brush arm 54 and consequently with each engagement of the dog in the clutch member 59, the control ring brushes will be rotated through one complete cycle around the periphery of control rings. This operation is repeated for each character to be transmitted.

At the receiving station, a rotary distributor unit similar to that at the transmitter is employed with the exception that no clutching arrangement is provided, and the receiving control ring brushes are caused to rotate continuously in synchronism with the receiving com- 1 mutator brushes by having the controlling brush arm as well as the commutator brush arm fixed to the continuously rotating shaft. The purpose of the control ring clutch employed at the transmitter was to hold the control ring brushes latched up so that brushes 52 would rest on the insulated portion 58, of control ring 48 to prevent the sending of stray impulses over the line due to commutator brushes 43 and 44 continuously traversing th commutator segments. How this accomplishes its purpose will become apparent from the circuit diagram (Fig. 4) and the description to follow. It is evidentthat if these stray impulses are prevented from getting out to the line from the transmitter, there should be none to guard against at the receiver, so that a receiver control ring clutch in this system is not necessary.

A circuit diagram which may be used at the transmitting station is shown in Fig. 4 and will .now be described with reference to that figure.

As has been previously explained, a plurality of control members such as contacts I8 (Fig. 3) are operated for each character to be transmitted but only four such control member groups (10, II, I2 and 13) are shown in Fig. 4, that being considered representative of the entire transmitter circuit for purposes of explanation. Impulses initiated from the operation of a control member group are stored up and controlled by means of twelve relays designated as RI to R-I2 inclusive. These relays are of the double-wound type, each having an energizing coil and a holding coil.

Assumed, for example, that A is the character to be transmitted. When the character key bar for the character A is depressed, contacts ID are closed for a brief interval of time as previously described, and four circuits are completed. A circuit is established from ground 80, contact Illa now closed, conductor BI, clutch coil 55, to grounded battery 82, thus energizing the clutch coil. At the same time circuits are completed to energize relays R-I, R3, and RIIJ. The R,I relay is energized by a circuit from contact 10b through conductors 83 and 84, R-I relay coil, and via common conductor 85 to grounded battery 82. The R-3 relay is picked up by a parallel circuit from contact 10C, via conductors 86 and 8! to the R--3 coil, common conductor 85 to grounded battery 82. Another parallel circuit energizes the R,III relay as follows: contact 10d, conductors 88 and 89, RI9 coil, common conductor 85, to grounded battery 82. These relays are each provided with three contacts designated generally as 98, 9| and 92, which close when the coils of these relays are energized. Contacts 90 of relays R-I, R-3 and R-Il] close to provide holding circuits for the coils of these relays as follows: grounded battery 82, common conductor 85, coils of relays R I, R-3 and R-I0, contacts 90 of these relays, conductor 93, brushes 53 on control ring 49 to ground 94. This circuit holds relays R-I, R--3 and RI0 energized until a point after the signals have been sent to the line when brushes 53 pass on the insulated portion 5| of their associated ring 49.

Contacts 9| and 92 of the above relays also close upon energization of these relays to prepare circuits between a direct current source of potential such as battery 95 and transmitter commutator segments 4II, 4I-3, and 42-2. These circuits are allowed to be completed when brushes 52 pass off the insulated portion 50 and on to the conducting portion of their associated ring 48. The polarity of the outgoing impulses will be plus on brush 43 and minus on brush 44 from segments I and 3, and minus on brush 43 and plus on brush 44 from segment 4. The circuits connecting battery 95 with commutator segments for impressing these polarities is as follows: Positive side of battery 95, conductor 96, contacts 9| of relays RI and R3, to commutator segments 4II and 4I-3 respectively; and from negative side of battery 95, conductor 91, brushes 52 now on metallic portion of ring 48, conductor 98, contacts 92 of the R-I and R3 relays, to commutator segments 42-I and 42-3 respectively. Also, for the impulse through the R,I8 relay, the circuit runs from the positive side of battery 95, conductor 96, contacts 9| of the R |0 relay via conductors 98a and 99 to commutator segment 422; and

from negative side of battery 95, conductor 97,

brushes 52, ring 48, via conductor 98 to contacts 92 of the R,-I9 relay, conductors I88 and NH, to commutator segment 4I4. Impulses are sent over the line from the segments upon which the potentials were impressed as brushes 43 and 44 pass over these segments.

A circuit diagram suitable for use at the receiver is shown in Fig. 5. With this circuit arrangement a total selection of 48' characters is possible from permutations of three impulses representing each character. The selection is effected by the use of relays, each with an energizing coil and a holding coil, a rotary distributor unit similar to that used at the transmitter without the clutch attachment, a polarity distinguishing means for the incoming impulses such as polarized relay II 0 (Fig. 5), a plurality of control and selection circuits, and a solenoid for each of the character keys. Assuming a synchronous system, commutator brushes III and H2 will be rotating correspondingly to brushes 4| and 42 of the transmitter, segment for segment. Also receiver control ring brushes H3 and H4 will be rotating continuously in fixed relation with brushes III and I I2 as has been previously explained.

In receiving the character A, to continue with the above example, the first impulse received is the impulse from transmitter segment 4I-I.

, This impulse was negative to the line leading from brush 44 and positive to the line leading from brush .43 at the transmitter. Consequently, at the receiver, polarized relay I 0 is caused to be energized and shift its armature I01 to the left closing contacts I88 and passing current through brush III to segment II5-I, conductor II'I, R-I3, conductor I I 8 to the other side of the line, thus picking up the R-I3 relay. A holding circuit for this relay is established through its contacts 9 from grounded battery I20, via conductors |2I to R-I3' coil, contacts 9 now closed, via conductor I 22 to brushes II4 on metallic portion of receiver control ring I24 to ground I25. Multiple contacts I26 associated with relay RI3 close, connecting relays RIl to R28 and R--24 to R-21 inclusive to segments 3, 4, 5, and 6 of the receiving commutators II 5 and H6 respectively.v The next impulse will The contacts I29 grounded battery I20, via conductors I30 and I3I to R-II coil, contacts I29 now closed, via conductor I22 to brushes II I on metallic portion of ring H4, to ground I25.

With the energization of relay RI'I, contacts I33 also close to connect one side of six character key solenoids (A, B, C, D, E and F) to one side of brushes l I3 which at this time are still on insulated portion I32 of ring I23. Consequently no circuit is as yet completed to one side of these solenoids from grounded battery I20.

The third impulse to be received in the permutation representing the character A will be of opposite polarity to the first two impulses. Polarized relay IIO will shift its armature I01 to the right, closing contacts I09, and current will pass through brush II2, commutator segment II6 I, then via conductor I34 through contacts I26f to the R-ZB coil, conductors I35 and H8, to the other side of the line. Contacts I36 close to establish a holding circuit for relay R.-25 from grounded battery I20, via conductor I2I to the Rr25 coil, contacts I36, conductor I22, brushes H0 now on conducting portion of ring I 20, to ground I25.

The energization of relay RF-25 causes the multiple contacts I31 associated with it to close and thereby connect one side of six solenoids (A, N, T, Y, U and BS) to ground I38. A battery circuit is now prepared through the coil of the A solenoid and will be completed when brushes II3 pass onto the metallic portion of ring I23. The circuit is as follows: grounded battery I20, via conductor I39 to brushes II3 on metallic portion of ring I23, conductor I40, contacts I33, solenoid A, contacts I31 now closed, conductor MI, to ground I38. The solenoid A is thus energized and is adapted to operate a suitable recording means such as has already been described. Immediately upon the completion of the recording portion of the cycle, the holding circuits for all relays are broken by the receiver control ring brushes passing onto the insulating portion of their respective control rings.

For any other character to be communicated, the operation of the circuits is similar and can be easily followed from the above description of the circuit operation for the character A. An example of the code which may be used in combining the impulses into permutations representing characters is given in the table below with polarities on each segment of transmitting commutator 42 on which the impulses are to be impressed.

segments A. N D Y mitting commutators. This method is so well known in the art that further description is believed unnecessary.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

circuits, means under control of the distributor means in accordance wtih the first impulse received to condition a predetermined number of said control circuits, means also controlled by the distributor means operating through one of the conditioned control circuits in accordance with the second impulse received to condition a predetermined number of said character selection circuits, and further means controlled by said distributor means operating through another of the conditioned control circuits to effect the completion of a single one of the conditioned selection circuits to select the character represented by said impulses. v

2. A communication system comprising, in combination, means to receive a plurality of impulses comprising rotary distributor means provided with a plurality of segments, control means cooperating with a predetermined number of said segments and arranged to be selectively operated in accordance with the first impulse received by said distributor means, a plurality of groups of control circuits cooperating with the remaining segments, one group of said control circuits being conditioned in accordance with the operated control means, a plurality of groups of selection circuits, means rendered operative upon reception of the second impulse from one of said remaining segments through its related control circuit within the conditioned group to prepare a set of said selection circuits, and means rendered operative upon reception of the second impulse through one of said conditioned control circuits related to another of said remaining segments to prepare another set of selection circuits, thereby completing a single selection circuit which is common to both sets of selection circuits.

3. A synchronous communication system comprising, in combination at the transmitter, rotary distributor means including normally inoperative transmission control rings and a constantly rotating commutator, a plurality of control circuits, key-controlled means for selecting a predetermined number of said control circuits for operation in accordance with the depression of a character key, further means controlled by the key at the same time for energizing another of said control circuits, clutching mechanism including a clutch magnet operated upon energization of the last-mentioned circuit to cause the transmission control rings to rotate with the commutator in a predetermined relation to bring the selected control circuits under the control of said commutator for the purpose of transmitting character impulses at a differential time in the commutator cycle.

4. A synchronous communication system comprising, in combination at the transmitter, rotary distributor means including a normally inoperative transmission control means and constantly rotating commutator, a plurality of control circuits, means for selecting a predetermined number of said control circuits for the operation in accordance with'a character, means to select another of said control circuits at the same time to render the transmission control means operative to subject the selected control circuits to the control of the commutator to transmit impulses representing the character at a differential time in the commutator cycle.

5. A synchronous communication system comprising, in combination at the transmitter, a plurality of groups of control members and a plurality of control circuits associated therewith, means to operate a predetermined group of said control members for selecting the related control circuits for operation in accordance with a character to be transmitted and for operating one of said selected control circuits at the same time, a normally inoperative transmission control means provided with clutching mechanism rendered operative upon the operation of said last mentioned circuit to condition the selected control circuits,

and a rotating commutator cooperating with said selected circuits for transmitting a plurality of timed impulses representing the character.

6. A synchronous communication system comprising, in combination at the transmitter, means to initiate a plurality of impulses representing a character, a plurality of control circuits including a plurality of relays under the control of said initiating means and adapted to be selectively energized thereby in accordance with the character to store the impulses to be transmitted, and a cyclically operating rotary distributor means for transmitting the impulses including a rotary control means for eifecting the deenergization of all relays at a predetermined time after the transmitting portion of the same cycle of the distributor means in which said relays were energized.

7. A synchronous communication system, comprising, in combination at the receiver, control means and selection means each comprising a plurality of relays, rotary distributor means for receiving character impulses and directing them to the control and selection means at a differential time in the rotary distributor cycle to selectively energize a predetermined number of relays therein, and rotary control means included in the distributor means for efiecting the deenergization of all relays at a predetermined time before the end of the rotary distributor cycle.

CHARLES R. DOTY.

CERTIFICATE OF CORRECTION Patent No 2,181,989-

December 5, 1959.

CHARLES 'R. DOTY.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction ere-follows: Page 11,, sect ond column, lines 20 and 21, claim 1, for "the first impulse rerality" read their polarities, aplurality; and that the said Letters- Patent should be read with this correction therein that the same may conform to the record ofthe case in the Patent Office.

Signed and sealed this 2nd day of April, A; D. l9h0.

(Seal) Henry Van Arsdale, Acting Commissioner of 'Pate nts.-

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