US2172060A

US2172060A - Printing telegraph system

Info

Publication number: US2172060A
Application number: US178016A
Authority: US
Inventors: Clyde J Fitch
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1937-12-04
Filing date: 1937-12-04
Publication date: 1939-09-05
Anticipated expiration: 1956-09-05

Description

5, 1939. c, Frrc 2,172,060

I PRINTING TELEGRAPH SYSTEM 7 Filed Dec. 4, 1937 7 Sheets -Sheet 1 27 J I lNVE T I H E0 ATTORNEY Sept. 5, 1939. FITC 2, 0

A PRINTING TELEGRAPH SYSTEM Filed Dec. 4, 1937 7 Sheets-Sheei 4 'llll-llllw m n "lll-llljl In FIG. 2

1. 1| up mus ill-ll llL ATTORNEY p 5', c. J FITCH I PRINTING TELEGRAPH sYs'rz'u 7 Sheets-Sheet 5 Filed Dec. 4, 193'! VEN 4W ATTORNEY Sept. 5, 1939. c, J F|TH 2,172,050

PRINTING TELEGRAPH SYSTEM Filed Dec. 4, 19137 7 Sheets-Sheet e ATTORN EY Sept. 5, 1939.' c. J. FITCH PRINTING TELEGRAPH SYSTEM 7 Sheets-Sheet 7 Filed Dec. 4, 1937 m Fri. v

lli I lu WHHHHI I H w BW L MI II .l llll LIIII w r l mi l nwT Patented Sept. 5, 1939 UNl'lED STATES- PATENT OFFICE 2,172,060 i PRINTING TELEGRAPH SYSTEM Clyde J. Fitch, Endlcott, N. Y., ,assignor gm Intel-national Business Machines Corporation, New York, N. Y., a corporation of New York Application December 4, 1937, Serial No. 178,016

10 Claims. (01. 178-25) This invention relates to printing telegraph systems and more particularly to novel means embodied therein to effect selection of a particular. group of printing instrumentalities from a plurality of such groups.

More specifically, the illustration of the principles of the presentinvention is shown to embody a standard form of typewriting mechanism wherein the printing instrumentalities comprise typebars having two types, one for lower and the other for upper case printing and associated mechanism to effect shifting of the typebars relatively to the platen for changing case. The said latter mechanism being of known construction whereby upon depression of the controlling shift keybar the type basket is shifted to upper case position and returned to lower case position, when the keybar is released; and it is -therefore customary to hold the-key depressed while writing upper case characters.

It has been proposed heretofore to provide control means so that upon successive reception of control signals the said means is effective to alter the positioning of the type basket and thereby effect the desired selection of the printing instrumentalities. In the present invention it is proposed to utilize a single control Signal, the transmission of which is prolonged as long as the printing of the selected group of instrumentalities is desired, that is, the control or shiftsignal is applied continuously to the control circuits as long, for example, as upper case printing is desired to be effected."

It is, therefore, an object of the present invention to provide means whereby control signals are applied continuously to a transmission medium in contradistinction to the aperiodic character signals.

Another object of the present invention is to provide means to maintain the control contacts operated continuously during a desired control period, whereas the character control contacts are operated aperiodically during the said control period.

Another object of the invention is to provide means whereby the initiation of the control signals are under control of the shift determining means.

Further objects of the instant invention reside in any novel feature of construction or operation or novel combination of parts present in the embodiment of the invention described and shown in the accompanying drawingswhether 5 within or without the scope of the appended claims and irrespective of other specific statements as, to the scope of the invention contained herein.

In the drawings 10 Fig. 1 is a sectional view of one standard type of typewriting mechanism.

Fig. 2 is an exploded view of certain control elements; the structural features of which are exaggerated to show clearly the normal operating 15 positions thereof.

Fig. 3 is a transverse sectional view of the shifting mechanism of the illustrated typewriter.

Fig. 3a is a detail view of the type basket shift control cam.

' Fig. 4 is a sectional view of one type of signal control means.

Figs. 5 and 6 are detail views showing the mechanism in Fig. 4 in operated positions.

Fig. 7 is a plan view of the mechanism shown in Fig. 4,

Fig. 8 is a sectional view of one type. of signal receiving permutation mechanism.

Fig. 9 is a perspective view of the control elements shown in Fig. 8. 30

Figs. 10 and 11 are detail views of the clutch unit.

Fig. 12 is aplan view of the mechanism shown in Fig. 8.

Fig. 13 is a diagrammatic circuit arrangement 35 of a suitable phase transformer.

Fig. 14 is a circuit diagram of a single control circuit of the signal generator.

Fig. 15 is a circuit diagram showing a complete signal generator and signal receiving system suitable for printing telegraph systems.

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 description.

Referring to the drawings and particularly to Fig. 1, well known means are provided for actuating the typebars I6, comprising a constantly rotating roller l0, cooperating with a series of individual power units each comprising a cam H, the engagement of the cams with the roller ,5;

being controlled selectively by the character keybars 11.

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. The cam H may be provided to be pivoted on,one arm of a bell crank lever 12 which is pivoted in the frame of the recording unit, as indicated generally by reference character t3, the other arm of the said bell crank lever is operatively connected with an arm of bell crank lever it by means of link it. Another arm of the said lever- I4 is connected to the typebars it in a well known manner, so as to effect operation of the typebars or any other suitable means connected to the bell crank levers upon selective operation of the controlling keybars H.

The pivoted bell crank lever II is operated by 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 keybar Ill 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 the units. In this position the impeller-arm I8 is urged, by the associated coil spring l9. against one of the impeller-lugs 20, which at the time is in the lower position, and tends to turn the cam H in a clockwise direction. This is prevented, however, by the engagement of one of the detents 2! on the cam, with the upper stop lug 2 2 on the stop lever 23. If, however, the corresponding keybar is operated, the bifurcated lower end (Fig. l) of extension arm 24 associated with oneof the said keybars l7 engages an arm 25 at the upper end of the stop lever 23 which is provided with an offset projection at its end which extends laterally through an opening in the bell crank lever E2. 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 springurged impeller-arm It. 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 until the high point has been reached and passed. This causes the .whole cam unit to swing around the pivot i3v so as to pull down the corresponding link and actuate one of the typebars or any 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 l8 tends to'continue the rotation thereof by engaging the second impeller-lug 29 of cam H 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 diflicult to release the keybar within this short interval, so that it is the lower lug 28 which is first engaged, but upon the release of the keybar 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 keybar 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 typebars and other operating mechanisms to be operated. It is to be understood that an individual cam unit is provided for each typebar 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 directions of movement, and the order of operation of the stop lugs, is reversed. For example, if the bifurcated arm '24--a is positioned to engage the arm 25-0. at the upper end of stop lever 23-41 by virtue of operation of the associated keybar, the said arm' is positioned rearwardly or to the left as viewed in Fig. l, and the lower end 'of the stop lever 23-11 is moved forwardly, that is, to the right as viewed in the said figure. This said operation is effective to release the cam, by virtue of positioning the lower stop lug 28--a out of the path of detent 2 Ia, thus permitting the springurged' impeller-arm l8--a. to rotate the cam slightly in a clockwise direction to effect engagement of the lower lobe of cam I l and power roller. Upon completion of a half revolution of the cam i I, the second detent 21-41 engages first the upper stop lug 22-a while the stop lever 23-a is in an operated position, but upon release of the associated keybar and the return of the said stop lever to normal position, this lug 22--a disengages the said detent and the impeller-arm rotates the cam slightly so that the said detent then engages the lower stop lug 28-0,, as shown in the figure. In this manner the bell crank lever l2-u is rotated about the pivot I3a to operate the associated typebar or any other mechanism associated therewith. For further structural details of the cam units, reference should be made to the above mentioned patent.

Referring now to Figs. 3 and 3a., a brief description of the type basket shift mechanism employed in the said typewriter will now follow; for a detailed description of this known structure reference should be made to U. S. Patent No. 1,945,097. This mechanism comprises a movably mounted type basket 30 upon which the typebars it are pivotally mounted for cooperation with the printing'point on the platen. Each of the typebars l6 has two types 3|, one for lower and the other for upper case printing. With the parts in the normal position shown in the figure, the lower one of the types engages the platen for printing when the typebar is actuated, and upon shifting the type basket the other type engages the platen for printing.

-The type basket is resiliently supported and guided in its case shift movements on the free ends of the

springs

32 and 33. Power actuated key controlled means are provided for shifting the type basket and comprises two toggles so arranged that one or the other is in its straightened position when the type basket is shifted to one or the other of its printing positions. One of said toggles comprises the link 34 pivoted at one end to a bracket 35 projecting rearwardly from the type basket. The other end of link 34 is pivoted to an arm of bell crank lever 36 fixed to one end of rock shaft 31 which extends to the other side of the type basket. The other arm of the bell crank lever 36 is connected with a toggle lever 38 by means of a link 39. By this arrangement the link 34 and associated arm of bell crank 36 constitute in effect a toggle moved in its straight position when the type basket is in its upper or normal position as shown inthe figure. The toggle lever 36 and link 39 constitute in effect a second toggle movable from the broken position shown to a straightened position. By means of the described toggle arrangements the type basket is given either a downward or upward movement respectively, thus efiectingselection of a certain group of instrumentalities from a plurality of such groups.

Power driven key controlled means are provided for actuating said toggles to shift the type basket. This said means is similar to the cam control units described hereinabove, except, however, the detent arrangement on the double lobe cam, so

that the type basket may be shifted to upper and 42 projecting laterally therefrom on opposite sides of its pivot, so that one or the other of which is engaged by the spring urged impeller-arm 43 tending to turn the cam into engagement with the roller. The cam also has a pair of laterally projecting

detents

44 and 45 arranged on opposite sides 'of and at different distances from its pivot and adapted to cooperate with a stop lug 46 provided on the lower end of stop lever 41.

It will be understood now, upon depression of the shift keybar 48, that the lower end of stop lever 41 is positioned to the right as viewed in the figure, moving the stop lug 46 from the path of detent 44 and into the path of detent 45, permitting the cam 49 to move into engagement with the roller under the action of impeller-arm 43.

By depressing the keybar, and by the engagement of its arm 49 with the interponent 50, therear end of the interponent is raised and maintained in this position as long as the keybar is held depressed. The cam 46 is turned through one-half a revolution until its detent 45 moves into engagement with the stop lug 46 on stop lever. During this movement of the cam the bell crank lever is tilted and swings arm 52 for-- wardly and with it interponent 56, which by its position engages the lug 53 and swings the lever 38 about its pivot 54 to straighten the

toggle

36 and 39 and break the toggle 34 and 36, thus swinging the type basket downwardly against the tension of the

spring arms

32 and 33. A shift lock mechanism 55 of known construction is shown to maintain the parts in the described position. Upon release of the shift keybar 46, the stop lever 41 is returned to the normal position shown in the figure, releasing detent 45 and positioning the stop lug 46 in the path of detent 43, so that again the cam 40 is rotated a half revolution. The interponent 50 is returned to the position shown in Fig. 3 when the keybar is released, so that the cam during its rotation causes the interponent 56 again to be actuated and engage the lug 56 on lever 38 to swing the lever to break its

toggle

36 and 39 and at the same time straighten the toggle 34 and 36 against the tension of

springs

32 and 33 to return the type basket to the normal lower case position.

When the described typewriter mechanism is used as a transmitting teleprinter embodying the present invention, the normally open contacts 51 may be provided to be suitably positioned-and secured to the frame of the machine, so that the downward movement of the type basket 36 causes the contacts to be closed, and opened when the basket is returned to the normal lower case 'position. When employed as a teleprinter receiver,

suitable solenoid means 56, shown in the dotted section in the figure, may be provided to maintain the keybar depressed during .the period the upper case printing is desired to be effected. The purpose of the contacts 51 and solenoid 56 will be understood as the description progresses. It is obviousfof course, that instead of printing upper and lower case characters upon shifting the type basket, any desired groups of characters or signs can be provided on the type-bars, so that, when the basket is in the normal position shown, one of the groups of characters are printed, and when shifted to the downward or lower position the other group of characters is printed. It is intended that such modifications be encompassed in the scope of the present invention.

Referring now to Figs. 4 to 7, one method of conditioning and controlling signal generating means suitable for printing telegraph systems is shown and is described in detail in the co-pending application Serial No. 113,798, dated December 2,

1936. The bell crank levers l2 associated with the character keybars H are provided with depending arms 59 supporting the cam rollers 60 suitably positioned so as to displace the selector members 6|, when the cam units are released and mounted on suitable slotted guide bars 62 secured to the frame of the typewriter unit. Each selector is provided with equally spaced studs 63 alternately positioned on the selectors, for example, three on each of the sides of the selectors. which are adapted to engage fingers 64 selectively positioned on the permutation bars 65 rotatably mounted in a suitable frame. Certain of the fingers64 extend above the'permutation bars 65 and others below the said bars. The purpose of this arrangement is described in detail in said application and need not be repeated here. The fingers and selectors are so arranged that upon displacement of the latter by the operation of the cam units the fingers and associated bars are rotated in a counterclockwise direction. In Figs. 5 and 6 certain of the selectors 6| are arranged so that the studded section is engaged by the fingers 64 extending below the permutation bars and that these selectors are operated by the forward bank of cam units; and other selectors have the studs 63 disposed so that they engage the fingers 64 extending above the permutation bars so operated. The said selectors 6| are slidably' tion will be given of one type of receiving perg mutation bar unit adapted to control selectively the operation of the printing instrumentaiities. This said unit is described in the co-pending application Serial No. 113,799, dated December 2, 1936, and comprises a plurality of differently slotted permutation bars 68 suitably mounted in is driven by the constantly rotating ratchet gear I3 by means of gears Id and 75 operatively connected to the power roller by suitable means such as belt 16. 5

Normally, the bars 68 are not operated in unison with the driving gear 13, due to the stop 18 engaging the dog lift lever TI which maintains the toothed dog I8 in the position as shown in Fig. 9. However, upon energization of the control magnet 19, the stop 76 is positioned out of the path of the pivoted dog lift lever ll, so that the spring 80 is effective to urge the slidable dog 18 and lever 11 to the right as viewed in Fig. 9

to permit engagement of the tooth 8| on the dog I8 and ratchet gear 13, thus operating the permutation bar 68 and gear I8 in unison.

The signal energizing the magnet 19 lasts momentarily so that upon deenergization thereof, the stop 16 again is positioned in the path of the lever 11 so that upon engagement of the stop 16 by said lever the toothed dog I8 is disengaged from the rotating gear 13. An individual clutch unit and associated magnet is provided for each permutation bar so that upon the energization of the said magnets in various combinations, in accordance with a selected code, different combinations of bars are rotated by the described clutch units to effect the alignment of the differently positioned slots on the permutation bars, thus permitting the levers 69 to be lowered in the aligned slots during the rotation of the bars. The said levers 69 by means of the links 10 are then effective to lower the controlling keybars of the. typewriter to eifect recording of the characters corresponding to the received character signalsby means of the described-power operated units controlled by the associated keybars.

Referring now to Figs. 13 to 15, one type of signal transmitting and receiving means is shown and is described in detail in the co-pending application Serial No. 156,443, and dated December 7, 1934. Briefly, the circuit arrangement shown in the said figures comprises a phase splitting means to generate a plurality of outof-phase voltages and applying the said voltages to individual control circuits, each including electric discharge devices adapted to emit a series of short signal impulses equally spaced with respect to each other. The signal generating circuits may then be applied simultaneously to a transmission medium controlling a receiving system similar in operation to the transmitting circuits.

In Fig. 13, a preferred type of phase-splitter 82 is shown to comprise two transformingmeans including the

primary windings

83 and 84 and the corresponding secondary windings 88-11 to 83-g and 84-11 to 8H. A condenser 85 is provided in the primary circuit of one and an indicator 86 in the primary circuit of the other, so that the voltages in said circuits are de grees out of phase and that the voltages across each of the primaries is the same. It is to be noted that the turns ratio of the individual secondary windings vary for each phase connecelectrical degrees apart, each phase of which is adapted to deliver equal voltages across the free ends of the secondary circuits. The described phase-splitter is employed in both the trans-- mitting and receiving circuits and indicated in these circuits generally by the reference characters 82-A and 82-B, respectively.

Referring to Fig. 14, anindividual tube circuit, which may be associated with any one of the secondary output circuits of the phasesplitter, will now be described and is shown to comprise an electric discharge device '1' equivalent to a full wave rectifier and triode in one envelope and which is well known in the art, commonly referred to as a "duplex diode triode type. The diode plates 81 are joined to the terminals of the secondary winding of transformer 88 and the shunt connected resistor IS, the center tap of which is connected to the grid 90 of the device T and by means of resistor 0| is also joined to the cathode 92 thereof. The

control contacts il-a and transformer Ql-a areinserted in the output circuit of the device.

terminal of the battery. This described condi-' tion exists in the circuit for only a. comparatively short time, because the bias on grid 90 is no longer zero and is not a constant factor, but

varies in a timed relationship with the frequency of the A. 0. supply source. The said supply source by means of transformer 88 is impressed upon the full wave rectifier section of the device and the rectified current impressed upon resistor immediately drives the grid bias negative with respect to the cathode. The value of the resistor 9| is adjusted so that, before the grid bias becomes effective to reduce the plate current to substantially zero value, a pulse is impressed upon the output circuit just traced so that a short signal impulse is impressed on the desired output circuit connected to the secondary winding of transformer Sl-a. It is understood how that, if the contacts are maintained in an operated position, a series of short equally spaced impulses will be continuously impressed upon the said output circuit, and that the frequency of the initiated signals is twice the frequency of the A. 0. supply source.

Referring now to Fig. 15, the operation of the signal generating and transmitting circuits will now be understood; the individual electric discharge devices T-l to T6 and associated cirsuits (the operation of each circuit and device precisely as just described) are connected to the individual output circuits of the phase transforming means 82--A, several circuits are shown only in detail. The contacts 61 (Figs. 4 to 6) included in the associated output circuits are connected in common to signal transmitting means which may be one of any of the known types of signal transmitters. The said contacts 61 represent the signal conditioning or initiating means and may be operated in different combinations by the mechanism described hereinabove to initiate various combinations of out-of-phase impulses representing the character signals.

Upon operation of any of the contacts 51 singly condensers are then effective or in different combinations equally spaced timed impulses will be initiated, the timing of the outof-phase impulses with respect to each other is controlled by the phase displaced voltages impressed upon the input circuits of the electric discharge devices.

The controlled circuits just described related to phase associated with phases l to 6 of the phase-splitter. Phase I is not shown to be included in the transmitting and receiving circuits; this phase may be used for other controlling purposes, not relevant to the present invention. Phase 8 is connected to a circuit arrangement, including discharge device T-8, similar to the ones described, but is shown to be controlled by the contacts 51, connected to the said common circuit, operated by the type basket (Fig. 3), whenever shifted by the shift determining means described.

The receiving circuits includethe electric discharge devices R--l to R.6 and R-8 and associated circuits which are similar to the transmitting circuits are shown to be connected to a similar phase transforming means 82--B connected to an A. C. supply source synchronous with the said supply source associated with the transmitting circuits- The individual anodes of the tubes are shown to be connected toa common circuit 96 to a source of plate potential, and the Y individual cathodes are connected to the condensers C! to C-6 and C'8, respectively, which in turn are connected to a common circuit 91 connected to the anode of control tube 98 which is biased so that normally there is no current flow in its output circuit, unless the received signal impulses are impressed on the input circuit thereof. It will now be seen, upon reception of the out-of-phase signal impulses, tube 98 permits current to flow in its output circuit so long'as the individual impulses are impressed thereupon. The circuits associated with the tubes R-I to Rr-6 and R-8 are rendered operative in timed relationship with ,the operation of the circuits associated with tubes T--I to T-6 and T--8 so that the received signal impulses are in phase with the corresponding operated receiving circuits, thereby permitting current to flow in the individual associated cathode circuits including the condensers C-l to C-ii and C8 and charging the corresponding condensers. For example, if the contacts 61 for phases I and 6 were closed momentarily to initiate and cause the corresponding signal impulses to be transmitted, upon reception of these im pulses, the receiving circuits corresponding to phases I and 6 thereat would be energized to charge the associated condensers C-l and C-6 to a predetermined voltage. The said charged to operate the nor mally biased tubes RT-l and RT-6 to energize the magnets 19 included in the output circuits of the said tubes, The magnets 19 '(Figs. 8 to 12) associated with tubes RT-I to RT-B correspond to the receiving permutation unit control magnets, thus operating the receiving recording unit effecting recordingof the characters correspond ing to the received character signal. It is to be noted that the magnet 58 (Fig. 3) associated with tube RT-B corresponds to the magnet described hereinabove to operate the shift determining means of the receiving recording unit. It should be mentioned that the charges on the grids of the tubes RT-l and RT6 and RT-8 are maintained so long as the transmitting contacts are closed, and that due to the time constants of the condensers Cl to C-6 and C8 and the associated resistors the impulses applied to the grids of the said tubes are relatively long, thereby delivering constant andsufiicient power to the said magnets.

The features of the present invention have now been described, and the method and manner of practicing this invention should be evident from the disclosure just set forth; however, a brief summary of operation of the system will now be given.

Let it be assumed that the typewriting or recording units are operated with the type baskets in the normal positions, that is, with the shift keybar in the normal inoperative position, so that upon selective operation of the character keybars I! at the transmitting unit the signal initiating or conditioning means, namely, contacts 67, are operated in different combinations or permutatively to operate the signal generating means'accordingly, thus causing the combinations of phase displaced impulses representing the character signals to be impressed upon the transmission medium.

The combinations of out-of-phase impulses are impressed upon the receiving circuits to charge the condensers CI to C 6 accordingly, thus causing different combinations of the controlling magnets"!!! to be energized, releasing the corre-, sponding permutation bars at the receiving unitand operating the associated keybars to record the characters represented by the received character signals. In this manner recording of the characters of one. particular group is effected. Now, in order to effect printing of the characters in a different group, at any time during the transmission of the abovementioned character signals the shift keybar 48 is operated and by means of shift lock 55 can be maintained in the said operated position for any desired period of time. While the shift keybar remains operated,

' the control contacts 51 are also maintained operative to initiate continuously the phase displaced control signals which are effective to charge the condenser C8 at the receiver and cause the magnet 58 to be energized constantly to depress the shift keybar at the receiving recording unit to shift the type basket in a position to correspond to the basket at the transmitting recording unit. Now, While the shift control contacts remain closed at the transmitting unit and while the shift control signals are continuously transmitted to maintain the shift determining means at the receiver unit operative, the character keybars i! are now operated selectively to initiate the phase displaced character signals which are impressed upon the transmission medium so that the corresponding groups of magnets 19 are energized to-effect recording at the receiver from the other and different group of printing instrumentalities. Printing from the first mentioned group of instrumentalities is effected again when the shift keybar at the transmay be made by those skilled in the art without 15 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.

What is claimed is as follows:

1. In a system of the character described, a plurality of typewriting mechanisms, each having a positionable type basket and controlling keybars therefor to position the basket from a normal position, signal control means controlled by the positioned type basket of one typewriting mechanism to initiate control signals as long as the type basket is positioned from the said normal position, and means controlled by said signals to operate the controlling keybar of the other typewriting mechanism to position the type basket thereof so as to correspond to the positioning of the type basket of the first mentioned mechanlsm.

2. In a system of the character described, a plurality of recording units, each having groups of printing instrumentalities shiftable to different positions and shifting control means for said instrumentalities, signal control means, controlled by said shifting control means when the printing-instrumentalities of one unit are shifted to effect printing of a certain group thereof, to initiate control signals as long as said printing instrumentalities remain in said shifted position, and means controlled by said signals to control the operation of the shifting control means of the other recording unit as long as the signals are initiated thereby maintaining the printing instrumentalities of the last mentioned unit shifted to correspond to those of the first said unit.

3. In a system of the character described, means to initiate control signals for a prolonged period, a remotely controlled recording nnitcomprising shiftable printing instrumentalities and control means therefor, and means controlled by the said control signals to control the said control means as long as the signals are initiated, including means for shifting the printing instrumentalities for a prolonged period of time.

4. A system of the character described comprising means to transmit aperiodic character signals and means to initiate shift control signals continuously, recording means having shiftable printing :instrumentalities and control means therefor, means controlled by the character signals to control the selective operation of the printing instrumentalities, and means controlled by the shift signals to control the said control means to shift the printing instrumentalities and maintain the printing instrumentalities in said shifted positionas long as the shift signals are initiated.

5. A system of the character described comprising means to initiate aperiodic character signals, shift determining means and means controlled thereby to initiate shift control signals continuously, recording means having shiftable printing instrumentalities and control means for the said instrumentalities and shift determining means therefor, means controlled by the aperiodic signals to control said printing instrumentalities control means selectively, and means controlled by the shift signals to control the second said shift determining means to shift the instrumen talities and maintain them in the shifted position -as long as the shift signals are initiated.

6. A system of the character described comprising a plurality of recording units, each having printing means and a shiftable member for said printing means, means controlled by one of said units to initiate aperiodic character signals and means controlled by the shiftable member thereof to initiate shift control signals continuously, means included in another recording unit, controlled by the aperiodic signals to control selectively the operation of the printing means, means controlled by the continuously initiated shift signals to control the operation of the shiftable member of the last mentioned recording unit, and means to maintain the said shiftable member operated as long as the shift signals are initiated.

7. A system of the character described comprising means to initiate aperiodic character signals and means to initiate periodic shift control signals, a recording unit having shiftable printing elements and means to control the shifting thereof, means controlled by said aperiodic signals to control selectively the operation of the printing elements, and means controlled by the periodic shift control signals to control the operation of said shifting control means including means for maintaining the last said means operative as long as the shift signals are initiated.

8. A system of the character described comprising character control contacts operated aperiodicallyto initiate character signals and shift control contacts operated constantly to initiate shift signals, a recording unit having shiftable printing elements and means to control the shifting thereof, means controlled by the character signals to control selectively the operation of the printing elements, and means controlled by the shift signals to control the operation of the shifting control means including means for maintaining the last mentioned means operative as long as the shift signals are initiated.

9. A system of the character described comprising means to initiate aperiodic character signals, and means to initiate periodic control signals, a recording unit having shiftable printing elements and means to control the shifting thereof, circuit means operated by the aperiodic signals to control selectively the operation of the printing elements, and a. circuit including means whereby the circuit is operated continuously by signals and means energized periodically by the signals to control the operation of the shifting control means including means for effecting shifting of the printing elements as long as the said last mentioned means is energized periodically.

CLYDE J. FITCH.